Classification of supplied components

Bakgrund: Elektroniktillverkaren The Company implementerade för 4-5 år sedan en ABC-klassificeringsmodell för klassificering av de komponenter som de köper in. Nu vill företaget utmana den nuvarande modellen och utvärdera om de använder korrekta parametrar för klassificering, för att undersöka om det finns möjlighet till förbättring. Därför efterfrågar The Company en ny modell som baseras på den teoretiska kunskap som finns inom området för att kunna göra en jämförelse med den befintliga modellen. Syftet med ABC klassificering är att hantera osäkerheter från leverantörer vad gäller leveranskvalitet, ledtidsvariationer och saldofel. Syfte: Syfte med examensarbetet är att föreslå en metod för att klassificera de komponenter som The Company köper in, och ge rekommendationer för hur denna kan användas. Modellen skall vara applicerbar inom alla The Company’s marknadssegment och utmana den nuvarande modellen. Problemdefinition: Vilka parametrar är lämpliga att använda för att klassificera de komponenter som köps in? Hur skall parametrarna kombineras för klassificering? Hur många klasser är rimligt att använda och hur skall dessa klasser delas in för att modellen ska vara användbar? Metod: Detta examensarbete har utförts med ett holistiskt perspektiv på klassificeringsmetoder. Ett abduktivt arbetssätt har applicerats på både kvantitativ och kvalitativ dataanalys genom intervjuer, benchmarking och data från företagets ERP-system. Författarna har använt sig av en iterativ process mellan teori och praktik. Resultat: Volymvärde, leverantörers ledtidsdifferens och artikelpris är de tre parametrar som The Company rekommenderas att använda för klassificering tillsammans med Ngmetoden. Vidare är rekommendationen att The Company ska fortsätta arbeta med tio klasser och att utgå ifrån 80-20 regeln vid klassindelning. Slutsats: Följande slutsatser om klassificering har dragits: - Det finns klassificeringsmetoder både med en och flera kriterier. Dessa metoder har utvecklats för att skapa en bättre klassindelning och vara mer användarvänliga. - De använda parametrarna kan både vara kvalitativa och kvantitativa, där de förstnämnda generellt sätt kräver mer arbete av användaren. - Det finns inga tydliga teoretiska riktlinjer för hur många klasser som ska användas. Klassindelningen beror oftast på vad som är möjligt i ett managementperspektiv. - Antalet artiklar i varje klass bestäms oftast efter 80-20-regeln eller efter tidigare erfarenheter.Background: The electronic manufacturing company The Company implemented a new model for ABC classification of supplied components about 4-5 years ago. Today, they want to challenge this model and evaluate if they have been using the correct parameters, or if improvement can be made. They wish for a new model that is based on the theory in field, to make a comparison with the existing model. The purpose with the ABC classification is to manage uncertainties from suppliers, in terms of delivered quality, variation in lead times and inventory errors. Purpose: The purpose of this thesis is to suggest a method for classification of supplied components at The Company that challenges the model currently used, and give recommendations on how to use it. The new model should be applicable to all The Company’s market segments. Problem definition: Which parameters are suitable to use to classify supplied components at The Company? How should the parameters be combined for classification? How many classes are reasonable to use and how should these classes be divided in order for the model to be useful? Methodology: This thesis has been performed with a systems approach, to capture the holistic view of classification models. The abductive research method is used with both qualitative and quantitative data collection through interviews, benchmarking and data from ERP system. The authors have used an iterative process between theory and practice. Results: This thesis has concluded that volume value, supplier lead time deviation and unit cost are suitable parameters to use for classification at The Company, together with the Ng-method. The recommendation is to continue working with ten classes, and use the 80-20 rule as guideline to divide the components. Conclusions: The following conclusions about classification could be drawn from this thesis: - Both single criterion and multiple criteria methods exist and are further developed to give better result and be more user friendly. - Input parameters could be of both qualitative and quantitative nature, where the former in general requires more work from the user. - There is no clear theoretical guidelines of how many classes to use, and it should depend on what is possible from a management perspective. - The difference in number of components in each class is often divided according to the 80-20 rule or according to experience

Respiratory symptoms and lung function in young adults with severe alpha(1)-antitrypsin deficiency (PiZZ).

BACKGROUND: Neonatal screening for alpha(1)-antitrypsin (AAT) deficiency was undertaken in Sweden between 1972 and 1974 when 129 infants with severe AAT deficiency (phenotype PiZ) were identified. The cohort has been followed up prospectively. METHODS: 124 PiZ subjects, still alive and still living in Sweden, were invited to a follow up examination at about 22 years of age. The check up included a clinical examination, spirometric tests, and a questionnaire on smoking habits and respiratory symptoms. RESULTS: Ninety eight subjects (97 PiZZ and 1 PiZ-) subjects attended the follow up. The mean age of the subjects was 22.5 years (range 19.8-24.8). The mean (SD) forced expiratory volume in 1 second (FEV(1)) was 98 (14)% predicted, vital capacity (VC) was 103 (14)% predicted, and the mean FEV(1)/VC ratio was 83 (7)%. Eighty six subjects had previously undergone spirometric tests. The median follow up time was 4.3 years (range 0.9-7.3). The mean annual change in FEV(1) (% predicted) was -1.2% (95% CI -2.1 to -0.3), in VC (% predicted) was -1.5% (95% CI -2.0 to -0.9), and in the FEV(1)/VC ratio (%) was -0.3% (95% CI -0.7 to 0.2). Twenty eight individuals (29%) reported recurrent wheezing. Fifteen subjects (15%) had been diagnosed by a physician as having asthma. Eighteen subjects reported that they had smoked at some time; 10 were current smokers. The mean number of pack years among the ever smokers was 3.4 (range 0.6-10.5). Ten of 18 ever-smokers and 18 of 80 non-smokers reported recurrent wheezing (p<0.01), while exertional dyspnoea was reported by six ever smokers and 11 non-smokers (p<0.05). Lung function test results did not differ significantly between ever smokers and non-smokers. CONCLUSIONS: Young PiZ adults have essentially normal lung function, but have a high prevalence of asthma symptoms. Smoking in these individuals is associated with an increased frequency of respiratory symptoms

Idiopathic Hemochromotosis and Alpha‐1‐Antitrypsin Deficiency: Coexistence in a Family with Progressive Liver Disease in the Proband

A patient with coexistent hemochromatosis and alpha‐1‐antitrypsin deficiency which led to cirrhosis and death despite adequate therapy for hemochromatosis is reported. Evaluation of the family revealed first degree relatives with iron overload and others with alpha‐1‐antitrypsin deficiency but none with both conditions. The role of family studies in the early recognition and possible prevention of overt clinical disease in individuals with either of these two genetic diseases is discussed. Copyright © 1983 American Association for the Study of Liver Disease

Hereditary alpha-1-antitrypsin deficiency and its clinical consequences

Alpha-1-antitrypsin deficiency (AATD) is a genetic disorder that manifests as pulmonary emphysema, liver cirrhosis and, rarely, as the skin disease panniculitis, and is characterized by low serum levels of AAT, the main protease inhibitor (PI) in human serum. The prevalence in Western Europe and in the USA is estimated at approximately 1 in 2,500 and 1 : 5,000 newborns, and is highly dependent on the Scandinavian descent within the population. The most common deficiency alleles in North Europe are PI Z and PI S, and the majority of individuals with severe AATD are PI type ZZ. The clinical manifestations may widely vary between patients, ranging from asymptomatic in some to fatal liver or lung disease in others. Type ZZ and SZ AATD are risk factors for the development of respiratory symptoms (dyspnoea, coughing), early onset emphysema, and airflow obstruction early in adult life. Environmental factors such as cigarette smoking, and dust exposure are additional risk factors and have been linked to an accelerated progression of this condition. Type ZZ AATD may also lead to the development of acute or chronic liver disease in childhood or adulthood: prolonged jaundice after birth with conjugated hyperbilirubinemia and abnormal liver enzymes are characteristic clinical signs. Cirrhotic liver failure may occur around age 50. In very rare cases, necrotizing panniculitis and secondary vasculitis may occur. AATD is caused by mutations in the SERPINA1 gene encoding AAT, and is inherited as an autosomal recessive trait. The diagnosis can be established by detection of low serum levels of AAT and isoelectric focusing. Differential diagnoses should exclude bleeding disorders or jaundice, viral infection, hemochromatosis, Wilson's disease and autoimmune hepatitis. For treatment of lung disease, intravenous alpha-1-antitrypsin augmentation therapy, annual flu vaccination and a pneumococcal vaccine every 5 years are recommended. Relief of breathlessness may be obtained with long-acting bronchodilators and inhaled corticosteroids. The end-stage liver and lung disease can be treated by organ transplantation. In AATD patients with cirrhosis, prognosis is generally grave

Plasma levels of alpha1-antichymotrypsin and secretory leukocyte proteinase inhibitor in healthy and chronic obstructive pulmonary disease (COPD) subjects with and without severe α1-antitrypsin deficiency

BACKGROUND: Individuals with severe Z α1-antitrypsin (AAT) deficiency have a considerably increased risk of developing chronic obstructive lung disease (COPD). It has been hypothesized that compensatory increases in levels of other protease inhibitors mitigate the effects of this AAT deficiency. We analysed plasma levels of AAT, α1-antichymotrypsin (ACT) and secretory leukocyte protease inhibitor (SLPI) in healthy (asymptomatic) and COPD subjects with and without AAT deficiency. METHODS: Studied groups included: 71 asymptomatic AAT-deficient subjects (ZZ, n = 48 and SZ, n = 23, age 31 ± 0.5) identified during Swedish neonatal screening for AAT deficiency between 1972 and 1974; age-matched controls (MM, n = 57, age 30.7 ± 0.6); older asymptomatic ZZ (n = 10); healthy MM (n = 20, age 53 ± 9.6); and COPD patients (ZZ, n = 10, age 47.4 ± 11 and MM, n = 10, age 59.4 ± 6.7). Plasma levels of SLPI, AAT and ACT were analysed using ELISA and immunoelectrophoresis. RESULTS: No significant difference was found in plasma ACT and SLPI levels between the healthy MM and the ZZ or SZ subjects in the studied groups. Independent of the genetic variant, subjects with COPD (n = 19) had elevated plasma levels of SLPI and ACT relative to controls (n = 153) (49.5 ± 7.2 vs 40.7 ± 9.1 ng/ml, p < 0.001 and 0.52 ± 0.19 vs 0.40 ± 0.1 mg/ml, p < 0.05, respectively). CONCLUSION: Our findings show that plasma levels of ACT and SLPI are not elevated in subjects with genetic AAT deficiency compared MM controls and do not appear to compensate for the deficiency of plasma AAT

Survival in severe alpha-1-antitrypsin deficiency (PiZZ)

<p>Abstract</p> <p>Background</p> <p>Previous studies of the natural history of alpha-1-antitrypsin (AAT) deficiency are mostly based on highly selected patients. The aim of this study was to analyse the mortality of PiZZ individuals.</p> <p>Methods</p> <p>Data from 1339 adult PiZZ individuals from the Swedish National AAT Deficiency Registry, followed from 1991 to 2008, were analysed. Forty-three percent of these individuals were identified by respiratory symptoms (respiratory cases), 32% by liver diseases and other diseases (non-respiratory cases) and 25% by screening (screened cases). Smoking status was divided into two groups: smokers 737 (55%) and 602 (45%) never-smokers.</p> <p>Results</p> <p>During the follow-up 315 individuals (24%) died. The standardised mortality rate (SMR) for respiratory cases was 4.70 (95% Confidence Interval (CI) 4.10-5.40), 3.0 (95%CI 2.35-3.70) for the non-respiratory cases and 2.30 (95% CI 1.46-3.46) for the screened cases. The smokers had a higher mortality risk than never-smokers, with a SMR of 4.80 (95%CI 4.20-5.50) for the smokers and 2.80(95%CI 2.30-3.40) for the never-smokers. The Rate Ratio (RR) was 1.70 (95% CI 1.35-2.20). Also among the screened cases, the mortality risk for the smokers was significantly higher than in the general Swedish population (SMR 3.40 (95% CI 1.98-5.40).</p> <p>Conclusion</p> <p>Smokers with severe AAT deficiency, irrespective of mode of identification, have a significantly higher mortality risk than the general Swedish population.</p

Lack of association between HLA antigen DR3 and α<inf>1</inf> deficiency in liver transplant recipients

The relationship between α1-antitrypsin deficiency (α-ATD) and the HLA antigen system was studied in 32 liver transplant recipients. Despite previous reports of an association of HLA antigen DR3 with homozygosity for α-AT ZZ, no such association was seen in this population of α-ATD homozygous ZZ patients with advanced hepatic disease. Thus, the reported association of HLA class II antigens and homozygosity for the Z allele for α-AT may be an artifact of either a small study population or geographic inbreeding and a coincidental association of certain HLA antigens with the presence of homozygosity for the Z allele of α-AT. © 1993 Plenum Publishing Corporation

Prevalence of genetic polymorphisms in the promoter region of the alpha-1 antitrypsin (SERPINA1) gene in chronic liver disease: a case control study

Contains fulltext : 89639.pdf (publisher's version ) (Open Access)BACKGROUND: Alpha-1 antitrypsin (A1AT) deficiency, caused by the Z allele (p.E342K) and S allele (p.E264V) in the SERPINA1 gene, can induce liver and pulmonary disease. Different mechanisms appear to be responsible for the pathogenesis of these divergent disease expressions. The c.-1973T >C polymorphism located in the SERPINA1 promoter region is found more frequent in A1AT deficiency patients with liver disease compared to patients with pulmonary disease, but data are lacking regarding contribution to the development of liver diseases caused by other aetiologies. AIM: To study the prevalence of c.-1973T >C, Z allele and S allele in a cohort of patients with liver disease of various aetiologies compared with healthy controls and to evaluate its effect on disease progression. METHODS: A total of 297 patients with liver disease from various aetiologies and 297 age and gender matched healthy controls were included. The c.-1973T >C polymorphism and Z and S alleles of the SERPINA1 gene were analyzed by real-time PCR. RESULTS: c.-1973T >C was similarly distributed between patients with liver disease of various origins and healthy controls. Furthermore, the distribution of c.-1973T >C was independent from aetiology subgroup. In patients with liver disease mean ages at of onset of liver disease were 44.4, 42.3 and 40.7 years for the c.-1973 T/T, T/C and C/C genotype respectively (NS). S allele heterozygosity was increased in patients with drug induced liver injury (DILI), (OR 4.3; 95%CI 1.1-17.2). CONCLUSION: In our study, c.-1973T >C polymorphism was not a risk factor for liver disease of various aetiologies. In addition, S allele heterozygosity might contribute to the development of DILI

Alpha-1-antitrypsin phenotypes in adult liver disease patients

Alpha-1-antitrypsin (AAT) is an important serine protease inhibitor in humans. Hereditary alpha-1-antitrypsin deficiency (AATD) affects lungs and liver. Liver disease caused by AATD in paediatric patients has been previously well documented. However, the association of liver disease with alpha-1-antitrypsin gene polymorphisms in adults is less clear. Therefore, we aimed to study AAT polymorphisms in adults with liver disease. We performed a case-control study. AAT polymorphisms were investigated by isoelectric focusing in 61 patients with liver cirrhosis and 9 patients with hepatocellular carcinoma. The control group consisted of 218 healthy blood donors. A significant deviation of observed and expected frequency of AAT phenotypes from Hardy-Weinberg equilibrium (chi-square = 34.77, df 11, P = 0.000) in the patient group was caused by a higher than expected frequency of Pi ZZ homozygotes (f = 0.0143 and f = 0.0005, respectively, P = 0.000). In addition, Pi M homozygotes were more frequent in patients than in controls (63% and 46%, respectively, P = 0.025). Our study results show that Pi ZZ homozygosity in adults could be associated with severe liver disease. Presence of Pi M homozygosity could be associated with liver disease via some mechanism different from Z allele-induced liver damage through accumulation of AAT polymers