Profit-oriented disassembly-line balancing

As product and material recovery has gained importance, disassembly volumes have increased, justifying construction of disassembly lines similar to assembly lines. Recent research on disassembly lines has focused on complete disassembly. Unlike assembly, the current industry practice involves partial disassembly with profit-maximization or cost-minimization objectives. Another difference between assembly and disassembly is that disassembly involves additional precedence relations among tasks due to processing alternatives or physical restrictions. In this study, we define and solve the profit-oriented partial disassembly-line balancing problem. We first characterize different types of precedence relations in disassembly and propose a new representation scheme that encompasses all these types. We then develop the first mixed integer programming formulation for the partial disassembly-line balancing problem, which simultaneously determines (1) the parts whose demand is to be fulfilled to generate revenue, (2) the tasks that will release the selected parts under task and station costs, (3) the number of stations that will be opened, (4) the cycle time, and (5) the balance of the disassembly line, i.e. the feasible assignment of selected tasks to stations such that various types of precedence relations are satisfied. We propose a lower and upper-bounding scheme based on linear programming relaxation of the formulation. Computational results show that our approach provides near optimal solutions for small problems and is capable of solving larger problems with up to 320 disassembly tasks in reasonable time

Gastroprotective activity of chloroform extract of Muntingia calabura and Melastoma malabathricum leaves

Context: Muntingia calabura L. (family Muntingiaceae) and Melastoma malabathricum L. (family Melastomaceae) are traditionally used to treat gastric ulcer. Objective: The present study determines the mechanisms of gastroprotective activity of the chloroform extract of leaves obtained from both the plants using several in vitro and in vivo assays. Materials and methods: Phytochemical screening, HPLC analysis, and antioxidant activity of the respective extract were carried out. Gastroprotective activity was determined using ethanol-induced gastric ulcer assay while the mechanisms of gastroprotection were determined using the pyloric ligation assay. The test solutions [8% Tween-80 (vehicle), 20 mg/kg omeprazole, and different doses of extracts (50, 250, or 500 mg/kg] were administered orally once daily for 7 consecutive days before the animals were subjected to ethanol induced gastric ulcers. Results: The chloroform-extracted M. calabura (CEMC) contains tannins, polyphenolics, triterpenes, and steroids while the chloroform-extracted M. malabathricum (CEMM) contains only triterpenes and steroids. CEMC, but not CEMM, exerted remarkably strong antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH)- (86% versus 16%) and superoxide- (73% versus 36%) radical scavenging assays. Both extracts demonstrated significant (p < 0.05) gastroprotection with the EC50 value recorded at 192.3 or 297.7 mg/kg, respectively. In the pylorus ligation assay, CEMC and CEMM significantly (p < 0.05) reduced the total and free acidity and volume; while increased the pH of gastric juice as well as the gastric wall mucus content in comparison with the vehicle-treated group. Discussion and conclusion: CEMC and CEMM exert gastroprotective effects in animals with ethanol-induced gastric ulcers via antioxidant and anti-secretory effects

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

KARAKTERISTIK FISIKO KIMIA DAN AKTIVITAS ANTIOKSIDAN TAUCO LAMTORO GUNG (Leucaena leucocephala) ANGKAK

Abstrak Tauco is shaped pasta products are yellowish and have a slightly salty flavor. Tauco making process is done by means of fermentation. Tauco used as a natural food seasoning as distinctive smell and taste. Tauco usually made from soybean. Unfortunately, soybean production can not meet the needs of domestic soybean that still need to import from other countries. To reduce dependence on it can be used soy substitutes, one of which is leucaena. This study aims to determine the proportion of soybean leucaena with long fermentation on the characteristic physico-chemical of leucaena_angkak tauco. The study used a completely randomized design (CRD) with 2 factors. The first factor, proportion soybean-leucaena 70%:30%, 50%:50% 30%:70%. The second factor, fermentation time of 3 weeks, 4 weeks and 5 weeks. The results showed that the best treatment was the treatment of soybean-leucaena (70:30) proportion and fermentation time 5 weeks resulted tauco with criteria that had a moisture content 24.952%. The ash 5.081%, soluble protein 79250 µg/ml, fat 4.075%, total acid 7.620%, total solids 18.167% brix, phenol 2781,25 ppm, antioxidant activity 45,68% and 76 favorite color,taste 76,and flavor 71. Key words : leucaena, soybean,  tauco, fermentation time Abstrak Tauco adalah produk berbentuk pasta yang berwarna kekuning–kuningan dan mempunyai rasa yang agak asin. Proses pembuatan tauco dilakukan dengan cara fermentasi. Tauco digunakan sebagai penyedap masakan alami karena bau dan rasanya yang khas. Tauco biasanya terbuat dari kedelai. Namun sayangnya, produksi kedelai tidak dapat memenuhi kebutuhan kedelai dalam negeri sehingga masih perlu mengimpor kedelai dari negara lain. Untuk mengurangi ketergantungan pada kedelai maka dapat digunakan bahan pengganti, salah satunya adalah lamtoro gung. Penelitian ini bertujuan untuk mengetahui proporsi kedelai:lamtoro gung dengan lama fermentasi terhadap kualitas tauco lamtoro gung-angkak. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan 2 faktor dan 3 kali ulangan, Faktor 1 proporsi kedelai:lamtoro gung 70%:30%,50%:50%,30%:70%. Faktor II lama fermentasi 3 minggu, 4 minggu, dan 5 minggu. Hasil penelitian menunjukkan bahwa perlakuan terbaik adalah pada perlakuan proporsi kedelai:lamtoro gung (70:30) dan lama fermentasi 5 minggu yang menghasilkan tauco dengan kriteria lama fermentasi 5 minggu yang memiliki kadar air 24,952%, kadar abu 5,081%, protein terlarut 79250 µg/ml, lemak 4,075%, total asam 7,620%, total padatan 18,167% brix,  Fenol 2781,25 ppm,aktivitas antioksidan 45,68%,dan tingkat kesukaan warna 76, rasa 76, dan aroma 71.   Kata kunci : lamtoro gung, kedelai, tauco, waktu fermentasi</p

Research challenges, quality control and monitoring strategy for Wire Arc Additive Manufacturing

Metal additive manufacturing is a high-growth process owing to the capability of producing parts with complicated geometries and custom facets for various applications. The low material input ratio to final part output, in which minimum raw materials are needed to produce complex parts and thin-walled components with a large volume envelop-to-volume ratio, is advantageous compared to the conventional method. The Wire Arc Additive Manufacturing (WAAM) method has undergone significant research and advancement because it can be utilised to produce large metal components at high deposition rates as well as low cost and with better mechanical and microstructural properties than other AM techniques. Because of the significant amounts of processing temperature, various issues and defects arise during the process, hampering high-quality component manufacturing in WAAM. In addition, these components often have an insufficient and poor surface, affecting the metal components' quality. This article reviews common defects and research challenges associated with manufacturing different metal and alloy components using the WAAM process. Various control strategies in WAAM methods, which are essential to reduce or minimise defects to form high-quality metal parts, are summarised. Recent research on implementing artificial intelligence (AI) in quality improvement is discussed. The strategy for quality control using the multi-sensor-based closed-loop system is proposed in conclusion. This strategy could serve as a roadmap for ensuring the deposit efficiency and quality of WAAM components under complex, high-volume manufacturing circumstances