An Aggregated Optimization Model for Multi-Head SMD Placements

In this article we propose an aggregate optimization approach by formulating the multi-head SMD placement optimization problem into a mixed integer program (MIP) with the variables based on batches of components. This MIP is tractable and effective in balancing workload among placement heads, minimizing the number of nozzle exchanges, and improving handling class. The handling class which specifies the traveling speed of the robot arm, to the best of our knowledge, has been for the first time incorporated in an optimization model. While the MIP produces an optimal planning for batches of components, a new sequencing heuristics is developed in order to determine the final sequence of component placements based on the outputs of the MIP. This two-stage approach guarantees a good feasible solution to the multi-head SMD placement optimization problem. The computational performance is examined using real industrial data.Multi-head surface mounting device;Component placement;Variable placement speed

Preliminary report of hepatitis B virus genotype prevalence in Iran

Aim: To determine the prevalence of hepatitis B virus (HBV) genotypes in Iranian hepatitis B surface antigen (HBsAg) carriers, chronic hepatitis B and cirrhotic patients. Methods: A total of 109 HBsAg-positive patients were included in this study. HBV genotypes were determined by using INNO-LiPA methodology which is based on the reverse hybridization principle. Results: The distribution of patients with different stages of liver disease was as follows: 95 (86.4) chronic hepatitis, 11 (10) liver cirrhosis, and 3 (2.7) inactive carrier. Of the chronic hepatitis and liver cirrhosis patients, 26.4 were HBeAg-positive while 70 were HBeAg-negative. Genotype D was the only detected type found in all patients. Conclusion: Classifying HBV into genotypes has to be cost-effective and clinically relevant. Our study indicates that HBV genotype D prevails in the Mediterranean area, Near and Middle East, and South Asia. Continued efforts for understanding HBV genotype through international co-operation will reveal further virological diffierences of the genotypes and their clinical relevance. © 2006 The WJG Press. All rights reserved

Are serial hematocrit measurements sensitive enough to predict intra-abdominal injuries in blunt abdominal trama?

Objective: Routine serial hematocrit measurements are a component of the trauma evaluation for patients without serious injury identified on initial evaluation. We sought to determine whether serial hematocrit testing was useful in predicting the probable injuries in blunt abdominal trauma. Materials and method: We performed a prospective study of trauma patients admitted in our observation unit over a 12-month period. Patients routinely underwent serial hematocrit testing in 6-hour intervals (two hematocrit levels). We compared trauma patients with a hematocrit drop of 5 and 10 points or more to those without a significant hematocrit drop. Results: Five hundred forty-two isolated blunt abdominal trauma patients were admitted to observation unit, and 468 patients (86.35) had serial hematocrit during their 6-hour stay. Of these patients, 36.11 had a hematocrit drop of 5 or more and 12.61 a drop of 10 or more. Of patients with the hematocrit drop >10, 50.8 have had diagnostic manifestations of intra-abdominal injury in both ultrasonographic and computed tomography scanning (P5 and positive imaging. Conclusion: Although serial hematocrit testing may be useful in specific situations, routine use of serial hematocrit testing in trauma patients at a level I trauma center�s observation unit did not significantly aid in the prediction of occult injuries. © 2019 Mosaddegh et al

BK virus-associated hemorrhagic cystitis in children suffering from malignancies: Report of three cases

BK virus-associated hemorrhagic cystitis (HC) is frequent in patients undergoing bone marrow transplantation, but it rarely occurs among other immunosuppressed patients particularly in those who are receiving chemotherapy for hematologic malignancies. Herein, we report three children with malignancies suffering from hemorrhagic cystitis due to BK virus infection who were successfully improved. Early detection of BK virus using RT-PCR technique was undertaken. With administration of antiviral agents; specifically, IVIG or leflunomide, BK virus-associated HC could be successfully managed in children affected by malignancies and consequently, chemotherapy of underlying disorder might be continued after virus elimination. © 2019, Iranian Pediatric Hematology and Oncology Society. All rights reserved

Supply chain downsizing under bankruptcy:A robust optimization approach

Research on supply chain network design has mainly pursued efficiency oriented objectives for boosting service level and profit. However, the priority of an enterprise facing bankruptcy pressure shifts to fulfill debt obligation with limited financial resources and survive downsizing. In this paper, we define a supply chain downsizing problem (SCDP) under bankruptcy as streamlining a supply chain network in order to balance a business survival and its long term profitability. We formulate a mixed integer programming (MIP) model with specific downsizing features, which maximizes the utilization of investment resources through a combined operation of demand selection and production assets reallocation. The corresponding robust counterparts of the MIP model are further developed based on robust optimization techniques for dealing with uncertainties of demands and exchange rates. We analyze and validate the proposed downsizing MIP model with a series of systematically generated test cases while its robust counterparts are studied extensively using a large generated case. The findings demonstrate the value of our approach in discovering detailed downsizing plans in magnitude and direction and provide valuable insight into how financial debt payback could be arranged, and in a unique way show managers how the reconfigured downsized network would mitigate and lead to a sustainable and higher economic value supply chain

The comparison between the effectiveness of six different tooth brushing methods on removing dental bacterial plaque

Statement of Problem: There are different tooth brushing methods for removing dental plaque from tooth surfaces. The effectiveness of these methods, and the time needed for instruction, learning and using seem to be different. Also, it is possible that the effectiveness of each method reduces with time, based on its difficulty level and the reduction of the patient s attention in following the given instructions. Purpose: The aim of this research was to compare the effectiveness of six different accepted tooth brushing methods on total and specific teeth, as well as on special tooth surfaces. The research also compared the time needed for instruction, learning and using the methods. Materials and Methods: The study was designed as a single blind randomised controlled trial protocol to compare the six accepted tooth brushing methods: Roll, Bass, Charters (C), Modified Stillman (MS), and Modified Bass in two ways (MB1-MB2). 15 volunteers were selected from the basic science level dental students at Tehran University of Medical Sciences. All the six methods were instructed to each volunteer, using a randomly selected sequence. Each participant should, therefore, pass six consequent courses, by the same sequences as follow: 1st Visit: After polishing the teeth, the participant was asked to abstain any kind of tooth cleaning. - 2nd visit (48-72 hours later): O Leary Plaque Index (PI) was recorded and then the randomised selected method was instructed. Then, the participant brushed his/her teeth and PI was registered again. The time needed for instruction and using the method was registered too. The participant was then asked to use this newly learned tooth brushing method twice a day for 7±1 days. - 3rd visit (7±1 days later): PI was recorded. The teeth were polished. The participant was asked to abstain any kind of tooth cleaning for 48-72 hours, as washout period of the previous method and preparation period for the next method (2nd visit of the next course). The final stage was comparing the results, in which the effectiveness of each method was evaluated based on the mean percentage of plaque reduction after the first usage, and also the mean percentage of the plaque remained after using the method for 7±1 days. The time needed for instruction, learning and using the methods were also compared. The statistical analysis was done using the SPSS software and variance analysis (randomised block design). Results: Considering all the teeth and their total surfaces; after 1st usage, the methods of C and MB1 were statistically more effective than the other methods. But the difference between these two methods was not significant. Also after 7±1 days, the differences between all methods were not statistically significant. On the posterior teeth, after 1st usage and also after 7±1 days, the method of C was significantly more effective than the others, with the exception of MB1 for which their differences were not significant. Also MB1 was significantly more effective than the methods of Bass and Roll, but only after the 1st usage. On the anterior teeth, after 1st usage, method of C was statistically more effective than the methods of Bass, MB2 and MS. Also MB1 was significantly more effective than MB2 and MS. But after 7±1 days, the differences proved insignificant. Considering the specific surfaces of the teeth; on the proximal surfaces, after the 1st usage of the methods, the methods of C and MB1was significantly more effective than the others, except each other, which their difference was not significant. But after 7±1days the method of C was statistically more effective only than the methods of Bass, MB2 and MS, and the method of MB1was significantly more effective than MB2. On the buccal and lingual surfaces the differences were not statistically significant at both stage of evaluation. When statistically considering the time needed for instruction, learning and usage, the method of C needed more time than Bass and Roll methods. In the same way, MB1 needed more time than Roll method. The most time needed was related to MB2 which was more than the time needed for the methods of Bass, Roll and MS (P<0.001 and α=0.05). Conclusion: The tooth brushing methods of Charters’ and a kind of Modified Bass method (in which Bass and Roll methods are used separately and consequently) were evaluated as the most effective methods

The redesign of a warranty distribution network with recovery processes

A warranty distribution network provides aftersales warranty services to customers and resembles a closed-loop supply chain network with specific challenges for reverse flows management like recovery, repair, and reflow of refurbished products. We present here a nonlinear and nonconvex mixed integer programming model for the design of the warranty distribution network of a semiconductor company which is operated by an outsourced third party logistics service provider. The application of the model to the real-life case provides an improved distribution network flow and rearranged warehouse and recovery locations, and resulted in weekly cost savings of 3.4% for the considered item