Clostridium Genus Humans

Sample details Pages: 22 Words: 6690 Downloads: 6 Date added: 2017/06/26 Category Science Essay Type Argumentative essay Did you like this example? Chapter 1 General Introduction: Members of the genus Clostridium are anaerobic, motile, Gram-positive, spore-forming rod present in nature especially in the soil. Microscopically, they have a long drumstick like appearance with a bulge situated at their terminal ends. Gram-staining is one of the easiest methods employed to identify them as the cell simply incorporates the dye while the spore does not take up the stain. Clostridium shows ideal growth when they are grown on blood agar at human body temperatures. Under unfavorable conditions for growth, however, the bacterium produces spores to tolerate the stressed environment where in, the active bacteria would not have survived. Clostridial species in their active forms secrete exotoxins responsible for specific and serious conditions such as tetanus, botulism and gas gangrene. The four clinically important species of Clostridium are C. botulinum, C. tetani, C. perfringens and C. difficile. Don’t waste time! Our writers will create an original "Clostridium Genus Humans | Sciences Dissertations" essay for you Create order 1.2 Types of Clostridium species important in humans 1.2.1 C. tetani Clostridium tetani is the bacterium which causes tetanus (lockjaw) in human beings. The spores of C. tetani can be acquired from all kinds of skin trauma and they outgrow in deep, necrotic wounds. In the anaerobic environment, the spores germinate and lead to the formation of active C. tetani cells. If these cells are present at the tissue level, then they release an exotoxin named tetanospasmin which affects the nervous system specifically by transmission via the neurons, eventually to the brain. One of the major effects of the toxin involves constant contraction of the skeletal muscles which occurs as a result of blockage of inhibitory interneurons which controls the contraction of muscles. Prolonged contraction of the muscles eventually leads to respiratory failure which has a high mortality rate if not treated early. One of the best ways to avert infections caused by C. tetani is to immunize oneself. 1.2.2 C. botulinum Clostridium botulinum is identified to generate one of the most powerful toxins till date and is the causative agent of the c food poisoning. Due to the fact that Clostridium spores are ubiquitous, they sometimes find their way into foods placed in anaerobic storages such as cans and bottles. Once the cans are completely sealed, the spores begin to germinate and the bacteria then secretes their toxin which has an effect on the peripheral nerve cells (McLauchlin et al, 2006; McLauchlin, Grant et al.,2006). Patients suffer from muscular flaccid paralysis apart from blurred vision. Immediate administration of an anti-toxin to the patient is necessary to raise the probability of survival. Infantile botulism is also caused in a very similar way but is far milder than its adult counterpart. The most frequent source for the spores which germinate in the infants intestinal tract is however honey. 1.2.3 C. perfringens This is a non-motile bacterium which is an invasive pathogen that can be contracted from dirt via large cuts or wounds. After spore germination takes place, C. perfringens cells proliferate and release their exotoxin which causes necrosis of the surrounding tissue (Clostridial myonecrosis destroys muscular tissues). The bacteria themselves produce gas that leads to a bubbly deformation of the infected tissues (Smedley et al.,2004) (Smedley, Fisher et al.,2004). In the United Kingdom and United States they are the third most common cause of food-borne illness, with poorly prepared meat and poultry being the main culprits in harboring the bacterium (Lin and Labbe 2003). The clostridial enterotoxin mediating the disease is often heat-resistant and can be detected in contaminated food and feces. The bacteria are killed at cooking temperatures, but the heat-resistant spores they produce are able to survive and may actually be stimulated to germinate by the heat. If the food is not eaten at once but is allowed to cool slowly, the bacteria produced when the spores germinate multiply rapidly. Unless the food is reheated so that it is piping hot (at least to 60oC and preferably to 75oC), the bacteria will survive. After ingestion, if there are sufficient numbers present, the bacteria will produce toxins and the toxins will cause symptoms. Infection with Clostridium perfringens normally causes diarrhoea and severe abdominal pain. It may occasionally cause nausea but it rarely causes vomiting or fever. 1.2.4 C. difficile First described in the 1950s, pseudomembranous enterocolitis was thought to be due to either Staphylococcus aureus, an organism that had become prevalent in hospital in-house patients who had received antibiotics (Keidan and Sutherland 1954) or to Candida albicans. In 1974, a prospective study of 200 patients who were treated with clindamycin were detected with diarrhoea in 21% and pseudomembranous colitis in 10%. A toxin produced by a Clostridium species was proposed as the cause of clindamycin-induced ileocaecitis in hamsters in 1977 (Bartlett, Onderdonk et al.,1977); later this toxin was isolated from the samples of patients stool, with evidence and counter-evidence presented for C difficile and Clostridium sordellii as causative organisms. However, by 1978, C difficile had been clearly identified as the causal agent of antibiotic-associated colitis (Chang, Bartlett et al.,1978). 1.3 Microbiology of C. difficile C. difficile is a Gram-positive, motile bacterium, spore-forming rod, toxin-producing, obligate anaerobe that is present in nature. Colonies are relatively large (2à ¢Ã¢â€š ¬Ã¢â‚¬Å"17 ÃŽÂ ¼m in length) rough, grey and fast growing; CCFA medium (consisting of cycloserine, cefoxitin, and fructose agar in an egg-yolk agar base) is highly selective for its growth (Aslam, Hamill et al.,2005). Clostridium also shows optimum growth when plated on blood agar at human body temperatures [Figure 1]. Over the past decade, it has become a very prominent nosocomial infection worldwide. It is notable that C. difficile infection caused ward closures in 5% of UK hospitals in 1993, and by 1996, this figure had risen to 16% (Popoola, Swann et al.,2000). In 1935, Hall and OToole first isolated this organism, designated it to be Bacillus difficilis, from the meconium and faeces of newborn infants (Tabaqchali and Jumaa 1995). The difficult clostridium was resistant to early attempts at isolation and grew very slowly in culture. The organism was shown to produce a lethal toxin in experimental animals, but since it was commonly found in the stools of healthy neonates it was classified as commensal and subsequently attracted little attention until 1974, when a comprehensive study showed that C. difficile was widespread in nature and could be isolated from the stools of several animal species and from patients faeces and genitourinary tracts (Hafiz and Oakley 1976; Bartlett 2007). Clostridium difficile is now the most frequent bacterial enteric pathogen in the developed world. This organism has been the recognized agent of 20% to 25% of cases of antibiotic-associated diarrhea and around 90% of serious pseudomemraneous colitis cases since its discovery in 1978. Disease symptoms are due to the production of tow toxins (A and B). During the past 3 to 4 years there has been the recognition of a new strain designated the NAP-1/ ribotype 027 strain which has been associated with some unique features including epidemics in geographically defined areas, more serious forms of disease and relative refractoriness to standard therapy. This 027 strain is linked to several deadly hospital outbreaks of C. difficile-associated diarrhea (CDI) which are now found rather frequently in Canada, the United States, and in greater parts of Europe (Cloud and Kelly 2007). This strain was found to produce greater than 10 times as much of toxin A and toxin B, as historic isolates (Larson, Parry et al.,1977; Cloud and Kelly 2007). The link between clindamycin associated colitis and C. difficile was not made until 1977. Stool filtrate from a patient with pseudomembranous colitis showed a cytotoxic effect on tissue culture cells, which suggested the presence of a toxin of unknown source (Larson, Parry et al.,1977). At the same time investigators in the United States showed that clindamycin and other antibiotics induced a fatal caecitis in hamsters; the caecal contents contained a filterable toxin that was cytopathic in a cell culture assay and would reproduce the typical lesions when injected intracaecally (Bartlett, Onderdonk et al.,1977). An organism identified as C. difficile was isolated from the animals and was shown to be the source of the toxin. Soon after, C. difficile and its toxins were detected in the stools of patients with pseudomembranous colitis (Hopkin 1978; Larson, Price et al.,1978), and oral vancomycin was shown to be an effective treatment in animal models and in patients (Bartlett 1984). C difficile has since become established as a major cause of nosocomial diarrhoeal infection. Figure 2: Coloured transmission electron micrograph of Clostridium difficle forming an endospore (red). Dr Kari Lounatmaa/Science Photo Library 1.4 Genome of C. difficile The genome of C. difficile strain 630 which was known as a virulent and multidrug-resistant strain was completely sequenced by Sebaihia in 2006 (Sebaihia, Wren et al.,2006). A large proportion of the genome (11%) consists of mobile genetic elements, mainly in the form of transposons. These mobile elements are supposed to be responsible for the acquisition of an extensive numbers of genes which are involved in antimicrobial resistance, virulence, and host interaction. The metabolic abilities encoded in the genome show multiple adaptations which enable the bacteria to survive and grow within the gut in low acidic environment. The genome consists of a circular chromosome of 4,290,252 bp with a G+C content of 29.06%, an additional circular plasmid of 7,881 bp with a G+C content of 27.9%, and 3971 genes. There are two separate genes, tcdA and tcdB encoded for enterotoxin A (308kDa) and cytotoxin B (270kDa) (Barroso, Wang et al.,1990; Dove, Wang et al.,1990; Hundsberger, Braun et al.,1997). Both toxins A and B, share 63% of amino acid sequence homology; enzymatic domain, a hydrophobic region believed to be involved in translocation through endocytic vesicles into the cytosol, and a carboxy-terminal domain which contain the so-called clostridial repetitive oligopeptides (CROPs); the latter mediate. TcdA and TcdB are among the largest bacterial toxins reported to date and are joined by Clostridium sordellii lethal toxin (TcsL) and hemorrhagic toxin (TcsH) and Clostridium novyi alpha toxin (TcnÃŽÂ ±) to form the group of large clostridial toxins (Table 1). TcdA and TcdB, located in a 19.6-kb pathogenicity locus (PaLoc), which is a short chromosomal segment carried by pathogenic strains of C. difficile which also encompasses three other small open reading frames [Figure. 2]. Nontoxigenic and nonpathogenic strains of C. difficile contain a 127-bp sequence (Hammond and Johnson 1995). The sequence similarity and its position suggests that the tcdA and tcdB genes are the result of gene duplication (von Eichel-Streiber, Laufenberg-Feldmann et al.,1992). The lack of toxin activity for nontoxigenic strains can be explained by the absence of at least part of the toxin A gene. The expression of these two genes is regulated by tcdC gene. The expression of the tcdC gene and weak transcription of the genes encoding toxin A (tcdA), toxin B (tcdB), a positive regulator (tcdD), and a holin-like protein (tcdE) (Hundsberger, Braun et al.,1997). The inverse is seen during the stationary phase, suggesting that tcdC negatively regulates toxin expression (Hundsberger, Braun et al.,1997) (232 amino acid residues). This gene is believed to result in over expression of tcdA and tcdB and increased production of toxins A and B, which may be responsible for the apparent higher pathogenicity in certain ribotypes (i.e., PCR type 027). Some strains also have cdtA and cdtB which are encoded for binary toxin (Sebaihia, Wren et al.,2006). 1.5 Pathophysiology The pathogenesis of CDI is complex and not fully understood but what is known is that important pathophysiological features of C. difficile include heat-resistance of the spore and toxin production. Also the precipitating event for C. difficile colitis is disruption of the normal colonic microflora which is usually caused by broad-spectrum antibiotics most commonly implicated (Figure 4), (Kyne, Hamel et al.,2002; Wilcox 2003) such as clindamycin, broad-spectrum penicillins, and cephalosporins. There are a number of antibiotics with a reduced propensity to induce infection such as aminoglycosides, metronidazole, antipseudomonals, and vancomycin. The risk of developing antibiotic-associated diarrhea is twice more when antibiotic therapy is received for longer than three days (Wistrom, Norrby et al.,2001). After disruption of the colonic microflora, colonization of C. difficile generally occurs by ingestion of the heat-resistant spores, which in turn switch over to their vegetative forms in the colon. Depending on the immunological status and the host factors, an asymptomatic carrier state or clinical manifestations of C. difficile colitis develop. Manifestation of the disease ranges from mild diarrhea to life-threatening- C. difficile colitis. C. difficile-associated diarrhea can occur up to eight weeks after the discontinuation of antibiotics. In most cases, C. difficile infection occurs on days 4 through 9 of antibiotic therapy (Cloud and Kelly 2007). As the leading cause of hospital-acquired diarrhoea, C. difficile colonizes the large bowel of patients receiving antibiotic therapy and produces two toxins, which are responsible for the disease pathologies. Toxin B is around 1000 times more cytotoxic than toxin A (Kabins and Spira 1975). Toxin A is also an enterotoxin in that it loosens the tight junctions between the epithelial cells that line the colon, which in turn helps toxin B to enter into the epithelial cells. These two toxins, TcdA and TcdB, are encoded on a pathogenicity locus with both negative and positive regulators of their expression. Following expression and release from the bacterium, TcdA and TcdB translocate to the cytosol of target cells and inactivate small GTP-binding proteins, which include Rho, Rac, and Cdc42. Inactivation of these substrates occurs through monoglucosylation of a single reactive threonine, which lies within the effector-binding loop and coordinates a divalent cation critical to binding GTP. By glucosylating small GTPases, TcdA and TcdB cause actin condensation and cell rounding, which is followed by death of the cell. TcdA elicit effects primarily within the intestinal epithelium, while TcdB has a broader cell tropism (Farrell and LaMont 2000; Voth and Ballard 2005). 1.6 Host factors The major host factors predisposing patients to the development of symptomatic C. difficile-associated Infections (CDI) include antibiotic therapy. A cohort study of Sherbrooke inpatients recorded that fluoroquinolone use (especially ciprofloxacin) has emerged as the major risk factor for CDI in the context of ongoing epidemic (Pepin, Saheb et al.,2005). Other risk factors include advanced age, especially people over 65 years; number and severity of underlying diseases and abnormal immune response to C. difficile toxins (Hundsberger, Braun et al.,1997). Patients who recently received immunosuppressive therapy or recently underwent surgical procedures are at the highest risk for fulminant disease, and those with a previous history of CDI. The increased risk may be due partly to the debilitated patients inability to mount an IgG antibody immune response against C. difficile toxin A. The ability to mount an immune response is not protective against C. difficile colonization, but is associated with decreased morbidity, mortality, and recurrence of CDI (Kyne, Hamel et al.,2002; Sebaihia, Wren et al.,2006). 1.7 Clinical presentation The presentation of the infection can range from asymptomatic colonization or self-limiting diarrhea to severe diarrhea, pseudomembranous colitis [Figur7], megacolon, colonic perforation, and death (Larson, Price et al.,1978). The incidence of diarrhea in hospitalized patients who receive antibiotics ranges from 3% to 29%. C difficile has been found as the causative agent in 10à ¢Ã¢â€š ¬Ã¢â‚¬Å"25% of patients with antibiotic-associated diarrhea, 50à ¢Ã¢â€š ¬Ã¢â‚¬Å"75% of those with antibiotic-associated colitis, and 90à ¢Ã¢â€š ¬Ã¢â‚¬Å"100% of those with antibiotic-associated pseudomembranous colitis (Bartlett 1990). Mortality of CDI ranges from 6% to 30% when pseudomembranous colitis is shown to be present (Olson, Shanholtzer et al.,1994; Moshkowitz, Ben et al.,2004; Pepin, Valiquette et al.,2004), and is substantial even in the absence of colitis. Most patients present with passing of large amounts of watery stool which is well known by healthcare workers who can often recognize it from its unique characteristic foul smell (Brazier 1998; Wilcox 1998). It was found in prospective case-controlled study that patients also present with paralytic ileus (21%), abdominal pain (22%), fever (28%) and a raised white cell count (50%) (Gerding, Johnson et al.,1995). Dehydration and electrolyte imbalance are often found due to passing large amount of diarrhea and, when disease is prolonged, significant malnutrition can develop (Brazier 1998). The incubation period for disease after exposure or acquisition is probably 1 week. Infection with C. difficile can be diagnosed up to 4 weeks after discontinuing an implicated antibiotic. It can also be triggered by other drugs such as cytotoxic drugs, antacids, stool softeners and laxatives which may trigger CDI (Hundsberger, Braun et al.,1997). Certain procedures such as nasogastric intubation, enemas and other intensive care procedures may also predispose to the infection (Cunney, Magee et al.,1998). 1.8 Treatment The initial treatment for CDI was oral vancomycin. In the early 1980s, metronidazole was also shown to be effective, perhaps equally so, and a strong preference to avoid the use of vancomycin in hospital inpatients, reinforced by several sets of therapeutic recommendations (Gerding, Johnson et al.,1995), has led to increasing reliance on metronidazole. In 1997, the American Gastroenterology Association published recommendations for treating CDI which include discontinuation of antibiotics to avoid tissue damage, supportive non-specific therapy, and addition of metronidazole for those who failed to respond within 2à ¢Ã¢â€š ¬Ã¢â‚¬Å"3 days (Fekety 1997). However, oral vancomycin was recommended for the following categories of patients: those who were critically ill, unable to tolerate metronidazole, pregnant women, or those under the age of 10 years, those who failed initial therapy with metronidazole, or those whose infecting organism proved to be metronidazole resistant. The past few years have witnessed an increase in the failure rate of antimicrobial therapy (Pepin, Valiquette et al.,2004). Some patients simply fail to respond to conventional therapy, and others relapse after discontinuation of treatment. The Cochrane database reports only nine well-designed randomized trials that have assessed treatments for CDI. Importantly, antimicrobial susceptibility testing of contemporary and historic isolates of NAP1/027 indicates a substantial increase in resistance to all fluoroquinolones (McDonald, Killgore et al.,2005). Fluoroquinolones are now the most widely prescribed antibiotics in many developed countries, (Linder, Huang et al.,2005) and the acquisition of fluoroquinolone resistance has been thought to promote the emergence of NAP1 (McDonald, Killgore et al.,2005). A substantial increase in the proportion of patients who fail to respond to metronidazole and a doubling of the frequency of postmetronidazole relapses have been noted, which could also promote the dissemination of this strain. 1.9Recommendations for treatment Treatment with the offending antibiotic has to be stopped, if possible. Fluids and electrolytes are given to compensate fluid loss during diarrhea. Antimotility agents should not be given. If specific treatment is required, metronidazole 500 mg is given orally every 6à ¢Ã¢â€š ¬Ã¢â‚¬Å"8 hours for 7à ¢Ã¢â€š ¬Ã¢â‚¬Å"10 days. Vancomycin at a dose of 125 mg orally every 6 hours is a second-line alternate agent. If the patient cannot tolerate the drug orally, intravenous metronidazole is used, but this should be switched to oral therapy once the patient is able to tolerate it. In the case of ileus or toxic megacolon, intravenous metronidazole is used, perhaps adding vancomycin retention enemas in a dose of 500 mg mixed in 100 mL normal saline. Vancomycin is avoided unless metronidazole seems to be ineffective, the patient is pregnant or allergic to metronidazole, or true resistance is shown. In case of recurrence, the agent that had been used to treat the initial episode of CDI is re-used, usually metronidazole. In case of multiple recurrences or refractory disease, the use of probiotics, immunoglobulin, or steroid is considered. In all cases, strict contact isolation of the patient is essential in controlling the spread of the disease to other patients. Symptom-free carriers not to be treated. Emergency colectomy reduces mortality in patients with fulminant CDI. Like patient who aged 65 years or more, in those immunocompetent, those with a leukocytosis or=20 x 10(9)/L or lactate between 2.2 and 4.9 mmol/L (Lamontagne, Labbe et al.,2007). 1.10 Epidemiology CDI is increasingly recognised as one of the most important healthcare associated infections. A number of aspects classify CDI as a severe potential threat associated with receiving healthcare. The number of cases reported on a weekly basis has steadily increased in Scotland over the last 10 years. Increasing numbers of outbreaks in hospitals and other healthcare institutions have been observed in Scotland as well as the rest of the UK. Some of these outbreaks have included cases of severe disease and deaths. Mortality rates for all deaths mentioning CDI as underlying or direct cause of disease have more than doubled from 1999-2004 in England and Wales. Reports indicate that patients complicated with CDI spend 1-3 weeks longer in hospitals than control group patients. Frequent relapses of the disease are contributing to difficulties with the treatment and may cause adverse health effects. The increasing numbers of elderly is furthermore expected to increase the risk of epidemics in t he future (Health Protection Scotland) Toxin-producing strains of C. difficile are carried in the normal colonic microflora of only about 5% of healthy adults (Kelly, Pothoulakis et al.,1994). However, 15% to 70% of neonates are carriers of C. difficile (Riley 1998). This percentage varies as a result of the degree of hospital exposure, birth in an environment where C. difficile is abundant, or if the neonate obtained maternal antibodies through breast milk. Although neonates are more frequent carriers of C. difficile, they do not often develop pseudomembranous colitis unless gastrointestinal motility disorders or other conditions (eg, severe neutropenia with leukemia) are present to increase the risk. Neonatal resistance to C. difficile colitis is believed to be due to the inability of the toxins to attach to the mucosa of newborns, because of immature membrane toxin receptors, or the protection from the toxins by maternally-acquired antibodies. After the first year of life, the carrier rate gradually decreases, reachin g adult levels by three years of age (Reinke and Messick 1994; Matsuki, Ozaki et al.,2005; Tonooka, Sakata et al.,2005; Trejo, Minnaard et al.,2006). Clostridium difficile-associated diarrhea (CDI) has become an increasing clinical problem as a nosocomial disease affecting mainly the elderly, patients with serious underlying diseases, and surgical patients (Bignardi 1998; Brazier 1998; Karlstrom, Fryklund et al.,1998). C. difficile probably represents the most common current cause of bacterial diarrhea in developed countries and, besides caliciviruses, the most common nosocomial diarrheal pathogen (Samore, DeGirolami et al.,1994; Karlstrom, Fryklund et al.,1998). Based on laboratory reports, at least 5,000 cases of CDI occur every year in Sweden, corresponding to 60 cases per 100,000 inhabitants per year, and more than 70% of the cases are associated with a hospital stay (Karlstrom, Fryklund et al.,1998). Currently over 6,000 cases were reported in Scotland from October 2006 until September 2007 (Health Protection Scotland). Clusters of nosocomial cases of CDI have been attributed to transmission of C. difficile between patients but also indirectly through the hands of health care workers or via contaminated surfaces or vomit (McFarland, Mulligan et al.,1989; Clabots, Johnson et al.,1992). Furthermore, some strains may be more transmissible and also more virulent than others and thus be associated with higher attack rates and a high local incidence of CDI (Johnson, Samore et al.,1999). A study performed over 10 years ago reported a low frequency of CDI in the community (7.7 cases/100 000 person-years of observation) (Hirschhorn, Trnka et al.,1994). A more recent report from the Centers for Disease Control and Prevention estimated that the minimum annual incidence of community-acquired CDI in the Philadelphia area between July 2004 and June 2005 was 7.6 cases/100 000 population (2005). Nine percent of patients in the present study had no previous exposure to the healthcare system, and were considered to be genuine cases of community-acquired CDI (Price, Dao-Tran et al.,2007). It was difficult to ascertain genuine cases of community-acquired CDI admitted to this tertiary care hospital. C. difficile is now the first organism suspected by health care personnel when a hospitalized patient develops diarrhea. C. difficile infection is a nosocomial disease that spread primarily by the medical staff, and hospital epidemics are relatively common. Usually, patients acquire the organism from the hospital and not from their own flora. C. difficile-associated disease (CDI) is increasingly being reported in many regions throughout the world. Moreover, severe disease has been reported in non-traditional hosts (e.g. younger age, seemingly healthy, non-institutionalized individuals residing in the community, and some without apparent antimicrobial exposure). In addition to the sudden increase in frequency of CDI, an increased rate of relapse/recurrence, disease severity and resistance to traditional treatment have also been noted. Much of this change was due to the emerg ence of one toxigenic strain, classified according to PCR as ribotype 027/toxinotype III and pulsed-field gel electrophoresis (PFGE) as NAP1 (Warny, Pepin et al.,2005) (Figure 8). This epidemic strain represented 2à ¢Ã¢â€š ¬Ã¢â‚¬Å"3% of hospital isolates of C difficile (Rupnik, Avesani et al.,1998; Rupnik, Brazier et al.,2001; Geric, Rupnik et al.,2004). By using restriction endonuclease analysis, the same genotype as NAP1/027 (also known as type BI) was found in only 14 of more than 6000 US historic isolates obtained before 2001 (McDonald, Killgore et al.,2005). NAP1/027 was not reported to cause either severe disease or outbreaks until recently, when it was identified as the cause of several outbreaks in the USA (McDonald, Killgore et al.,2005). In Sherbrooke, between 2003 and 2004, it was found that as many as a sixth of inpatients with health-care-associated C difficile as a direct or indirect consequence of this infection (Pepin, Valiquette et al.,2005). On June 4, 2004 tow outbreaks of NAP1 were reported in Montreal, Quebec and Calgary, Alberta, in Canada (Eggertson 2004). Sources put the death count as low as 36 and high as 89, with approximately 1,400 cases in 2003 and within the first few months of 2004.C .difficile infection continues to be a problem in the Quebec health care system in the 2004. As of March 2005, it has spread into the Toronto, Ontario area, hospitalizing 10 people. One has died while the others have been discharged. A dominant strain that was pulsed-field gel electrophoresis (PFGE) type NAP1, toxinotype III, and contained a tcdC deletion and ctdB was also discovered in samples from a Stoke Mandeville Hospital in the United Kingdom between 2003 and 2005 and from other outbreaks which were associated with increased morbidity, frequent need for colectomy, and mortality in the USA (McEllistrem, Carman et al.,2005). This strain has also been implicated in an epidemic at two Dutch hospitals (Harderwijk and Amersfoort, both 2005). Moreover, retrospectively the strain has been identified in isolates from sporadic US cases obtained in the early 1980s (McDonald, Killgore et al.,2005). The finding of an association between NAP1/027 (or BI) and high toxin production in the context of an epidemic associated with a high case-fatality ratio confirms the suspicion that the epidemic in Quebec and UK is caused by a more virulent strain (Pepin, Valiquette et al.,2005). In the UK, where the number of reported cases of CDI doubled over 3 years, NAP1/027 is the cause of ongoing outbreaks in at least three hospitals with a high case-fatality ratio (health protection agency). The appearance of this virulent strain, in association with certain environmental and antimicrobial exposure factors, may be combining to create the perfect storm (Owens 2007). In 2005 C. difficile spores was isolated from 12 (20%) of 60 retail ground meat samples purchased over a 10-months in Canada. Eleven isolates were toxigenic, and 8 (67%) were classified as toxinotype III. which suggests that C. difficile also could be responsible for food poisoning or at least be foodborne. Previously, a study investigating the role of psychrotrophic clostridia on blown pack spoilage of commercial packages of chilled vacuum-packed meats and dog rolls reported 2 incidental isolates of C. difficile (Moorhead and Bell 1999). In Bacteriological evaluation of commercial canine and feline raw diets C. difficile was isolated on direct culture from 1 turkey-based food (Weese, Rousseau et al.,2005). In terms of cost and productivity, C. difficile is a major burden to our health care system. There are estimated to be 250,000 to 300,000 cases of C. difficile a year in U.S. hospitals, which cost hundreds of millions of dollars for hospital care. Hospital costs for this condition in the USA (Kyne, Hamel et al.,2002) and UK (Wilcox, Cunniffe et al.,1996) exceed US$4000 per case. A typical case results in 1 to 2 extra weeks of patient care costing roughly $10,000. This price assumes that the patient responds to treatment and does not relapse or develops complications (Wilkins and Lyerly 2003). The incidence of CDI has increased in the past decade, with a 10-fold increase reported in Quebec (Pepin, Valiquette et al.,2004), as has the proportion of patients who have severe, refractory, or recurrent disease (Musher, Aslam et al.,2005). The successful control of C. difficile will require healthcare systems (including administrators, and leadership within several departments such as environmental services, infection control, infectious diseases, gastroenterology, surgery, microbiology and nursing), clinicians, long-term care and rehabilitation facilities, and patients themselves to be proactive in a collaborative effort (Owens 2007). 1.11 Reservoirs, sources, and transmission of C. difficile The major reservoirs for C. difficile in the hospital and community infection are patients with CDI or asymptomatic carriers of C. difficile. Patients with symptomatic disease heavily contaminate their immediate hospital environment and the spores can persist for several months on surfaces. Shedding of C. difficile into the environment depends on the patients status. In one study, they compared the rate of environmental contamination in rooms of patients with C. difficile-associated diarrhea to that of contamination in rooms of C. difficile asymptomatic carriers. They showed that contamination was significantly higher in rooms of patients with diarrhea compared to asymptomatic carriers. They also analyzed contamination in rooms without C. difficile-positive patients and found a contamination rate of 8%, showing that spores of C. difficile can persist, despite routine cleaning of rooms (McFarland, Surawicz et al.,1990). C. difficile diarrhea was reported as a community acquired infection in Ireland in 1998 (Kyne, Merry et al.,1998). CDI has also been reported in the community as an emerging pathogen in animals. Early typing comparisons did not identify animals as an important source for human Infection. In 1983 C. difficile was isolated in household pets such as dogs and cats in the UK (Borriello, Honour et al.,1983). In 2001 in Canada C. difficile was also associated with diarrhea in dogs and cats (Weese, Staempfli et al.,2001) but recent report in 2006 from Canada have shown a marked overlap between isolates from calves and humans, including two of the predominant outbreak types, 027 and 017 which suggested that C. difficile may be associated with calf diarrhea, and cattle may be reservoirs of C. difficile for humans (Rodriguez-Palacios, Stampfli et al.,2006). C. difficile has also been found in retail meat samples, suggesting that food could be involved in the transmission of C. difficile from animals to humans (Rupnik 2007). Over the past 5 years, C. difficile has emerged as a major cause of neonatal enteritis in pigs. Piglets 1à ¢Ã¢â€š ¬Ã¢â‚¬Å"7 days of age are affected (Songer and Anderson 2006; Yaeger, Kinyon et al.,2007), with gross lesions frequently including mesocolonic edema. Colonic contents may be pasty-to-watery and yellow, although some piglets are constipated or obstipated. In 2007 a study was carried out to assess the correlation between the presence of C. difficile toxins (TCd) in the colon contents of neonatal pigs and a number of parameters, including gross evidence of diarrhea mesocoloninc edema, typhlitis, and colitis. They found C. difficile may represent an important subclinical issue in neonatal swine (Yaeger, Funk et al.,2002). In 2006 study from Zimbabwe was to determine the prevalence of C. difficile in faeces of domestic animals (chickens, rabbits ,cattle, and goat), soil and drinking water in a rural community. The results of the study have shown that 95% of the samples were positive for C. difficile and chickens are a major reservoir of C. difficile in rural communities in Zimbabwe, where it was isolated in 17.4% of chicken feces samples. Detection of C. difficile in well water and household-stored water demonstrates the potential of water as a source of infection. Some of the water contamination may have been through faecal material of some domestic animals such as chickens, cattle and goats, which are kept as free-range animals in the community studied. Also it was found that C. difficile was not-uncommon cause of enteric disease in mature horses, mostly when they are treated with antimicrobials and hospitalized (Baverud, Gustafsson et al.,2003; Baverud 2004). In 2006 a first report of C. difficile as the main cause of fatal enterocolitis in elephant came from Denmakr when they retorted two cases of fatal enteritis caused by C. difficile in captive Asian elephants are reported from an outbreak affecting five females in the same zoo. It is speculated that the feeding of large quantities of broccoli, a rich source of sulforaphane, which has been shown to inhibit the growth of many intestinal microorganisms may have triggered a subsequent overgrowth by C. difficile (Bojesen, Olsen et al.,2006). Transmission of C. difficile is thought to occur via the oroà ¢Ã¢â€š ¬Ã¢â‚¬Å"fecal route. Outbreaks in hospitals and typing of strains suggested that transmission is probably via staff hands. A study documented positive hand cultures in 59% of hospital personnel caring for patients with positive culture (Samore, Venkataraman et al.,1996). Transmission can also occur by direct contact with contaminated surfaces. Some reports also suggested a transmission by direct inoculation into the bowel via contaminated materials such as thermometers (Jernigan, Siegman-Igra et al.,1998). Factors that may explain the ease of transmission include resistance of the spores to the most commonly used disinfectants and antiseptics, the antibiotic pressure in hospitalised patients and the promiscuity of patients. Unrecognized patients with C. difficile, or re-admissions of patients with C. difficile, can contribute to the reintroduction and spread of C. difficile to other patients or the environment. By using restriction endonuclease as a typing method, showed that 84% of cases of nosocomial acquisition of C. difficile strains were preceded by a documented introduction of the strain to the ward by another asymptomatic admission (Clabots, Peterson et al.,1988). 1.12 C. difficile typing methods 1.12.1 Phenotyping method: C. difficile has been typed by using different methods based on phenotypic properties; one of these methods was antibiograms, which was one of the early methods. Isolates resistant to three different antibiotics were found in one of the first documented outbreak investigations (Burdon 1982). Those isolates were found in the surgical ward and were distinct from isolates in the rest of the hospital. However, this method is at best only preliminary, and more detailed approach was tried by WÃÆ' ¼st and co-workers who combined soluble protein polyacrylamide gel electrophoresis (PAGE), plasmid analysis, immunoelectrophoresis of extracellular antigens and antibiograms to a number of isolates from related cases of C. difficile infection (Wust, Sullivan et al.,1982). By using these methods, they showed that 12 of the 16 strains were similar, showing strong evidence, that cross-infection had taken place. A combination of bacteriophage typing and bacteriocin methods has been used which showed a high percentage of non-typeable strains (Sell, Schaberg et al.,1983). In 1981 the immuno-chemical fingerprinting of EDTA-treated cell extracts of C. difficile was evaluated (Poxton and Byrne 1981). Nakamura and co-workers were the first investigators to use serum agglutination as a typing method by raising three antisera against C. difficile (Nakamura, Mikawa et al.,1981). This method could differentiate four marked serovars among 79 isolates from healthy carriers. In 1985 DelmÃÆ' ©es group improved this method and developed a serotyping scheme that could recognise 19 distinct sero-groups (Delmee, Homel et al.,1985). This method is repeatedly used as the standard by which other typing methods are compared. These early typing methods were developed to understand the epidemiology of C. difficile infection at a local level, which were adequate for local use; there was a need for typing schemes that could be implemented to further understanding of the epidemiology of C. difficile disease on a wider scale. To facilitate this, comparisons between typing schemes were performed, and in 1988 Mulligan and co-workers found good correlation between the types recognised by serotyping, PAGE, plasmid profiling of cell surface antigens and immunoblotting (Mulligan, Peterson et al.,1988). Sodium dodecyl sulfate (SDS)-PAGE of whole-cell proteins was applied to 79 isolates in an outbreak investigation, which yielded a maximum of approximately 40 bands ranging in size from 18 to 100 kilo-daltons (kDa). This investigation showed 60 of the 79 isolates was similar. Serogrouping was compared to SDS-PAGE of EDTA-extracted cell surface antigens and 61 isolates were analyzed (Ogunsola, Ryley et al.,1995). This method showed bands of sizes between 30 and 67 kDa and distributed their 79 isolates into 17 groups, which were similar to the results of serogrouping. A method of whole-cell fingerprinting by pyrolysis mass spectrometry (PMS) has been successfully used in investigating C. difficile outbreaks which had the advantage that it could cope with a large number of strains and had a high degree of differentiation (Magee, Brazier et al.,1993). However, the disadvantages of this method were the high cost of the equipment and its inability to assign a permanent type to a strain. 1.12.2 Molecular typing methods: In terms of the stability of marker expression and providing greater levels of typeability, molecular typing methods are generally regarded as superior to phenotypic methods and a number of molecular methods have been used in C. difficile. Due to the sparse distribution of the extra-chromosomal genetic elements within the species, plasmid profiling proved largely unsuccessful. However, in 1987 Kuijpers group analyzed the chromosomal DNA of C. difficile by using whole cell DNA restriction endonuclease analysis (REA) in which HindIII was used in the investigation which showed cross-infection between two patients in the same room (Kuijper, Oudbier et al.,1987). REA is a highly reproducible and discriminatory method; however, the disadvantages are it is very labor-intensive and a technically demanding procedure, especially for large numbers of isolates. An alternative genotypic method (Saiki, Scharf et al.,1985) called the restriction fragment length polymorphism (RFLP) which involves initial REA digestion followed by gel electrophoresis and Southern blotting was used to detect specific restriction site heterogeneity. RFLP, however, is also a very labor-intensive method and REA/RFLP methods have generally been replaced by methods based on the polymerase chain reaction (PCR). Another genotypic method is called arbitrarily primed PCR (AP-PCR) which permits the detection of polymorphisms within the target genome without prior knowledge of the target nucleotide sequence. A closely related method is called random amplified polymorphic DNA (RAPD). This method commonly uses two oligonucleotide primers which are arbitrary sequences and short in length (c.10 bp). In 1994, a method was evaluated by Barbut and co-workers using two 10-bp primers in an investigation of antiobiotic-associated diarrhea (AAD) in AIDS patients (Barbut, Mario et al.,1994). The discriminating ability of t this method was virtually unlimited as it was always possible to use other random primers. It is also simpler and more rapid than the other molecular methods which came later on such as restriction enzyme analysis or pulsed field gel electrophoresis. PCR ribotyping was first applied to C. difficile by using specific primers complementary to sites within the RNA operon this was carried out by Gurtler who targeted the amplification of the spacer region between the 16S and 23S rRNA regions (Gurtler 1993). C. difficile was shown to possess many copies of the rRNA genes, which differ in number and size between strains and also within the same genome. This approach was modified by Cartwright and co-workers who tested it in 102 isolates obtained from 73 symptomatic patients (Cartwright, Stock et al.,1995). The primers used in this study were the same primers used by Gurtler, and instead of using denaturing PAGE gels, their PCR fragments were separated by straightforward agarose gel electrophoresis. Furthermore, they showed that the quantity of DNA used in the reaction does not affect the banding patterns which was a problem associated with AP-PCR and RAPD methods. This approach was modified for the routine use by ONeill and co-workers who improved and simplified the DNA extraction method by using modified primers to the 16Sà ¢Ã‹â€ Ã¢â‚¬â„¢23S spacer region. This method was able to produce fragments ranging from 250 to 600 bp separated by agarose gel electrophoresis (Cartwright, Stock et al.,1995). Since 1995, this method has been used routinely by the UK Anaerobe Reference Unit in Cardiff, which provides a C. difficile typing service for the UK. A library consisting of 116 distinct ribotypes from over 3000 strains from all sources examined, has been constructed (Stubbs, Brazier et al.,1999). Contrary to the other methods, the whole genome is analyzed by pulsed field gel electrophoresis (PFGE) after digestion with rare cutting restriction endonucleases, such as SmaI, KspI, SacII or NruI, which result in 10 fragment length polymorphisms per strain. PFGE has been applied successfully to investigate 30 epidemiologically unrelated isolates and 22 isolates of C. difficile from an outbreak in an elderly care centre (Talon, Bailly et al.,1995). PCR ribotyping was considered more distinctive than AP-PCR and PFGE methods in a study (Collier, Stock et al.,1996). The disadvantages of PFGE include the initial cost of the equipment, the slowness of the procedure and its complexity. Bidet and co-workers compared all three methods and concluded that PCR ribotyping, is the best technique for C. difficile ribotyping (Bidet, Lalande et al.,2000). It was noted that some strains are untypeable by PFGE due to degradation of the extracted DNA and those strains belong to serogroup G, which corresponds to PCR ribotype 1 in the Stubbs group library (Stubbs, Brazier et al.,1999). Rupnik has developed the toxinotyping method by describing 11 toxinotypes and has been compared to PCR ribotyping (Rupnik, Brazier et al.,2001). Good correlation has been noted between the two methods, whilst applying toxinotyping to each type in the PCR ribotype library, five novel toxinotypes were discovered (Brazier 2001).

Athens V.Sparta Compare/Contrast Essay - 848 Words

Athens vs. Sparta Ancient Greece was comprised of small city-states, of which Sparta and Athens were two. Athens was renowned as a center of wisdom and learning. The people of Athens were interested in arts, music, and intellectual pursuits. Sparta, on the other hand, was recognized for its military strength. A Spartans life was centered on the state, because he lived and died to serve the state. Although the competing city-states of Sparta and Athens were individually different as well as governmentally diverse, they both managed to become dominating powers in Ancient Greece. Athens became a democracy under the rule of Solon in 594 B.C. In addition to eliminating serfdom, Solon altered the stringent laws of a previous ruler,†¦show more content†¦He did not retire until age sixty. On the contrary, in the Athenian military, a soldiers rank was decided by his social or economic status before he entered the army. Instituted by Solon in the sixth century B.C., four classes made up the Athenian social ladder. Defined by income, each class had a certain measure of political responsibility. The wealthiest class supplied the army with leaders. Called the hippeis or horsemen,† the second class made up the Athenian cavalry. The third class, called the zeugitai, made up the foot soldier, or hoplite section of the army. Finally, the poorest class, called the thetes, served either as oarsmen for the Athenian fleet, or as archers on land. In addition, while Spartan soldiers trained for thirteen years, Athenian soldiers only trained for two years. Thus, while Spartan military rank was determined by a persons performance after entering the army, the soldier’s social class predetermined Athenian military status. Unlike their husbands, Athenian women were forced to stay indoors at all times. They were controlled by their fathers through childhood and by their husbands after marriage. Mostly uneducated, except for learning how to read, they spent their time managing the household and slaves. They were only allowed to leave the house to attend certain religious festivals. In contrast with Athenian women, Spartan women led a free life and

Extension Lightweight Design Thinking Tools â€Myassignmenthelp.Com

Question: Discuss About The Extension Lightweight Design Thinking Tools? Answer: Introduction The conceptualization of a new product service is one of the most demanding and mentally taxing things in todays world. In a market competition that is so fierce and an unforgiving market conditions make it even harder to be able to penetrate any market or industry with something new. It is vital to come up with something that would be able to grab the consumers attention easily and ensure itself a proper and extended market share. Even though it is virtually impossible to invent something entirely new in a marketing scenario where technology dominates everything and has almost every single need of the consumers covered, it is still possible to innovate on something already existing in the market. The innovation should be something revolutionizing, nonetheless, or the customers would be reluctant to opt for the new product and stop using the product they already use. This innovation motive has led the desire to design the app that would help the customers to avail necessary products, while still keeping the environmental needs in mind. There are many restaurants in almost all parts of the country, which close down relatively early in the evening. This makes it very difficult for some of their customers to avail the food from their preferred restaurants because their work is not wrapped up by then or maybe due to being stuck elsewhere or simply because of traffic (Papargyropoulou et al., 2014). Swinton has made an app that would help the customers to be able to avail these food items even after the restaurants are closed. Moreover, the items will be priced at half of their actual prices so that even a bigger customer faction can be used. Furthermore, this would be beneficial for the restaurants as well because their food products will not be wasted. The app would be aiming to balance the market needs as well as the environmental aspects of running a business. Currently there are no other apps or services that offer this benefit and Swinton hopes that their uniqu e services would be hugely popular. The prime objectives and vision of the innovation Food wastage is a major issue in todays world (Lawrence, Richards Lyons, 2013). Where there are people and children in parts of the world, who are so unprivileged that, they cannot afford even the basic necessities, the first world countries waste food at an alarming rate, daily. This is a serious issue and needs to be dealt with at an earliest. Swinton is focused to contribute even a small part in this global problem and try to reduce food wastage. While adhering to the environment is important, at the core of any business lays the interest of the customers and the motive to generate a profit. Swinton believes that their initiative will show a positive outcome and both the customers and the planet will be benefited from the initiative. The business plan It has been noticed that many people in the country hold grievances for not being able to order their favorite food from their favorite diners because many of them close at about 6 pm. This makes even the restaurants incur a loss as their daily food go to waste and they have to restock everything again the next day as the country has strict laws about fresh food products (Farr-Wharton, Choi Foth, 2014, December). Swinton has been conducting financial surveys to understand whether the customers would be interested in being able to avail the food items at their preferred time, after the restaurants have closed for the night, at a price lower than the actual prices. It has also been conducting surveys to get an insight about the collective mindset of the restaurants to fathom whether they are interested to sell the food at a lower price. Market results are showing positive results: both parties have shown genuine interest in the idea. The restaurants are going to be benefited because t heir food will not go to waste (Cannone Ughetto, 2014). The customers are happy because their favorite food will not elude them because of traffic anymore; as well as they will be available at half of the prices. Restaurants will have to pay a certain amount as subscription for the app, which will highlight the products of each restaurant to the customers, based on the location of the customer. This would further enable the customers to choose from an array of options. Above all, the environment will be taken care of as no excess food will have to be disposed off. The humanitarian grounds of the app will surely make it attractive for many (Armstrong et al., 2015). Launch plans and tools to be used Swinton has already designed a basic form of the app and market tests are soon to be executed. The company knows that just designing the app is not the final goal, rather it is just the beginning of the journey. The app has to be launched into the market in a proper way. It has to exploit advertising and other marketing tools to ensure maximum market exposure and the most market share possible (Liedtka, 2015). In order to achieve this Swinton still has to carry out a number of tasks to reap the benefits of the app. Launching the app into the market requires just as much as designing, thinking, planning and execution as it needs to create the product itself. Rather, market launching is a more complex and extensive process, because it has to take care of a number of aspects and market surveys are incredibly taxing. The tools that are supposed to be used by Swinton are: The first basic things that are to be understood are the three questions of What? How? Why? These are the three primary questions that are used to understand why would something be produced or innovated in the first place: the market demands for it (Manzini Coad, 2015). Visualization: In order to create the solution of a problem, one must first understand the problem in depth and in its entirety. Interviews, market observations must be done to understand the market, and they yield a huge amount of data. These data have to be analyzed to properly, and coherently, understand what are the drawbacks of the sector and what can be done to help solve the problems. Visualization is the first step towards of creating any product, as well as understanding how to market a new product so that the customers can understand the extra benefits the product is offering, which is not provided by the other similar products (Norman Verganti, 2014). Swinton is using all the data collected to understand the market needs and hope to advertise the app into the market in such a way that would help the customers to understand the difference easily. Journey mapping: Mapping the journey means that the entire path that is to be taken towards success has to be understood before even setting off to the new venture. This may be considered as an extensive part of the visualization process itself. It is essential to have a prior knowledge about how would the product serve the customers, or how would it have to be projected on to the market so that maximum people opt for it. This journey planning is being extensively done by Swinton to understand the customer mentality and how would that be met. The market introduction plan will be helped if the company knows exactly what issues is the product going to solve. Value chain analysis: This tool would enable the company to cohesively understand why would their app be opted for by the customers: what would the value be for the customers against the money they are going to spend (Amit Zott, 2014). It also would help the company to understand its own value from delivering the app to the market. Mind mapping: The journey begins with a single idea revolving around the notion to help the customers and give them a service they should be getting already. More ideas are subsequently attached to it as the venture progresses. Currently, the company understands that their product would enable the customers, the restaurants and the environment to be benefited. Further plans and ideas would be developed along the journey, based on the needs or requirements that would be noticed (Carlgren, Rauth Elmquist, 2016). Brainstorming: Considering a lot of ideas and holding extensive meetings so that no information is left out or no0 stone is left unturned, would make sure that Swinton explores all the aspects of running a business before being introduced into the market. Swinton has teams that are specifically aimed to keep discussing different ideas which would help the company to explore different paths and marketing tactics to further help the motive of making the app in the first place. Concept development: Being able to rapidly develop upon a single idea or concept is essential for keep the business interesting and appealing to the customers. The product has to be constantly upgraded, in lieu with the changing customer demands. Swinton will be first establishing a proper idea about the purpose of the app and the customer interests in question and then decide upon the marketing strategies accordingly. Assumption testing: This tool is a mode to understand the key assumptions, which serve as a guideline to understand the reason for creating a service. This tool will be extensively used by Swinton to fathom and bridge the gap between the customer demands and the services offered. These are all hypothetical scenarios and have to be assessed carefully and properly before randomly jumping into a decision (Frow et al., 2015). Prototyping: Every product has to be tested in reality and on-hand, before being rolled out to the market. Swinton has created prototypes of the app, that will enable the company to make necessary changes along the way, as new problems are faced or shortcomings are observed. Co-creation: There are no other better to understand the market demands than the customers themselves. Swinton hopes to get help from the customers they aim to serve to gain insights about what features can the app have to be successful in the market. Launch planning: The final step would be requiring the company to use these very same tools once again to effectively launch the app into the market so that maximum business is ensured. Currently, the company believes that most of the tools are being used in a way that is revealing about the market requirements and the advertizing process is being shaped in accordance. Resources plan A resource plan is a tool to understand all the resources that are needed to create a successful business plan (Posner, Binz Roth, 2015). The resources that are to be used by Swinton are Teams to execute market analysis and conduct surveys Understanding the tools to be used to create the launch plan and to develop the app Where will the chosen locations be The response of the people who have been given the prototype app as a test Long-term planning The only motive of Swinton is to keep serving its customers. In the long-run it hopes to continue generating a profit an d develop the app even further, so that the ever changing customer requirements are always met. The other biggest long-term goal is to be able to help the environment by successfully reducing food wastage. This motive drives the company more than anything else. Recommendations Swinton should take a more analytical approach towards the launch planning of the product, so that the introduction would be flawless and the app would generate the maximum profit, while keeping the environment in mind and being sure not to cause any harm by its activities and operations. Conclusion From the above discussion, it can be concluded that, Swinton is on the right path to be successful in the market with the new food delivery app. The app has a huge advantage of being introduced into a market that does not have many competitors. This advantage, coupled with a proper launching plan, would be sure to become a successful business. The tools that will be used by the company look assuring in terms of solidifying the position of the app in the market. All the necessary tasks involving the creation and perfecting the app is being done. The launching plan is also on the cusp of completion. For now, the plan seems to be progressing according to the original blueprint of the company. The launching plan hopes that maximum market attention is ensured, which would help the company to serve the consumers keeping the ideals of Swinton in mind: balancing business and the environment. References Amit, R., Zott, C. (2014). Business model design: a dynamic capability perspective.J. Manage. Armstrong, G., Kotler, P., Harker, M., Brennan, R. (2015).Marketing: an introduction. Pearson Education. Cannone, G., Ughetto, E. (2014). Born globals: A cross-country survey on high-tech start-ups.International Business Review,23(1), 272-283. Carlgren, L., Rauth, I., Elmquist, M. (2016). Framing design thinking: The concept in idea and enactment.Creativity and Innovation Management,25(1), 38-57. Farr-Wharton, G., Choi, J. H. J., Foth, M. (2014, December). Food talks back: exploring the role of mobile applications in reducing domestic food wastage. InProceedings of the 26th Australian Computer-Human Interaction Conference on Designing Futures: the Future of Design(pp. 352-361). ACM. Frow, P., Nenonen, S., Payne, A., Storbacka, K. (2015). Managing co?creation design: A strategic approach to innovation.British Journal of Management,26(3), 463-483. Lawrence, G., Richards, C., Lyons, K. (2013). Food security in Australia in an era of Answer:ural Studies,29, 30-39. Liedtka, J. (2015). Perspective: Linking design thinking with innovation outcomes through cognitive bias reduction.Journal of Product Innovation Management,32(6), 925-938. Manzini, E., Coad, R. (2015).Design, when everybody designs: An introduction to design for social innovation. MIT press. Norman, D. A., Verganti, R. (2014). Incremental and radical innovation: Design research vs. technology and meaning change.Design issues,30(1), 78-96. Papargyropoulou, E., Lozano, R., Steinberger, J. K., Wright, N., bin Ujang, Z. Psychology. The food waste hierarchy as a framework for the management of food surplus and food waste.Journal of Cleaner Production,76, 106-115. Posner, B., Binz, H., Roth, D. (2015). Extension of the Lightweight Design Thinking Tools for the application on more complex problems. InDS 80-5 Proceedings of the 20th International Conference on Engineering Design (ICED 15) Vol 5: Design Methods and Tools-Part 1, Milan, Italy, 27-30.07. 15.

Properties of Organic Compounds free essay sample

The temperature of the gas phase rises again until it reaches the boiling point of a second content in the mixture and so on. By simple microscale distillation, we purified an unknown organic compound and then identified the unknown organic compound by using the boiling point and density measurements. Procedure/Results 5 mL of the unknown impure organic A was collected in an Erlenmeyer flask. A simple distillation apparatus was assembled and 3 mL of the unknown impure organic A was transferred into the distillation flask along with 3 boiling chips. A thermometer was then suspended down the middle of the condenser to record the distillation temperature. The mixture was heated gently and a pure solvent started to collect in the distillation flask. Two different fractions were collected. The first one was the forerun, which was collected before the temperature stabilized and the second one was when the temperature of the boiling compound began to stabilize. We will write a custom essay sample on Properties of Organic Compounds or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The unknown impure organic A was identified using density and boiling point measurements collected. Another simple distillation apparatus was assembled to find the boiling point of the unknown impure organic A. 3 mL of the unknown impure organic A and 3 boiling chips were transferred into the distillation flask and heated gently until the substance started to boil. The unknown impure organic A produced 0. 3 mL with a boiling point of 55Â °C for fraction one, which resulted in the density to be 0. 86 g/mL. 1. 2 mL was produced for fraction two with a boiling point of 58Â °C, resulting in a density of 0. 3 g/mL. The unknown impure organic A was then identified as acetone. Acetone has a boiling point range of 56-57Â °C and a density of 0. 791 g/mL. The observed boiling point range was 49-52Â °C with a volume of 2. 4 mL and a mass of 1. 71 g, resulting in a density of 0. 713 g/mL. Discussion: Acetone has a boiling point range of 56-57Â °C and a density of 0. 791 g/mL. The unknown impure organic A was identified as acetone due to having a boiling point range of 49-52Â °C and a den sity of 0. 713 g/mL. The boiling point range of the unknown impure organic A was lower than acetone’s actual boiling point range by 4-7Â °C, but was close enough to be identified as acetone because the density was only 0. 078 g/mL lower also. Therefore, both the density and boiling point measurements were good methods to use to identify the unknown impure organic A. Since the product wasn’t in exact value to acetone, errors could’ve occurred in the experiment. The boiling point could have still been trying to increase when we thought it had stabilized at 52Â °C, or liquid could’ve been lost due to spillage in transferring it to the distillation flask. Conclusion The objective of the experiment was to identify the unknown impure organic A with the boiling point and density measurements by using a simple microscale distillation to purify it. Our results correctly identified the unknown impure organic A (with few errors) and proved the distillation process valid. This experiment could be improved by recording more fractions, or repeating the fractions several times and recording the boiling point more than once to improve accuracy.