Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB). The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP) machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm), and the solder height is the table speed of the SP machine (2.5 mm/s).     

Factors associated with treatment failure of patients with psychiatric diseases and injecting drug users in the treatment of genotype 2 or 3 hepatitis C chronic infection

Background: Genotype 2/3 hepatitis C virus (HCV) has a good response to treatment with peginterferon and ribavirin. Patients with psychiatric disorders and injecting drug users (IDUs) are considered ‘difficult to treat’ and are often excluded from treatment despite the lack of evidence supporting this decision. Aims: To investigate the outcome and factors associated with treatment failure in these groups. Methods: This is an observational study of a cohort of patients infected by genotype 2/3 HCV. IDUs and patients with psychiatric diseases were not excluded from treatment. We performed an intention‐to‐treat analysis to evaluate factors related to treatment failure. Results: A sustained virological response (SVR) was achieved in 91 of the 125 patients treated (72.8%). Patients with chronic psychotic disorders or former IDUs had SVR rates similar to other groups. After multivariate analysis, independent factors associated with treatment failure were liver cirrhosis [odds ratio (OR) 3.4, 95% confidence interval (CI) 1.1–10.4], a history of depression and not being on antidepressants at the commencement of HCV treatment (OR 4.4, 95% CI 1.2–16) and active IDUs (OR 7.3, 95% CI 1.77–30.4). Conclusions: Patients with a history of depression who were not receiving antidepressants and active IDUs are more likely to fail treatment for genotype 2/3 HCV and will need additional support.     

Non-HDL cholesterol is strongly associated with coronary artery calcification in asymptomatic individuals

BackgroundGrowing evidence shows that non-high-density lipoprotein cholesterol (Non-HDL-C) is a strong and independent predictor of cardiovascular disease (CVD). Few studies have assessed the association between traditional lipid measures and subclinical end points. In this study we analyzed the association of Non-HDL-C, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) with coronary artery calcium (CAC), a marker of subclinical atherosclerosis.MethodsThe study population consisted of 1611 consecutive asymptomatic individuals (67% men, mean age: 53 ± 10 years) referred to a single electron beam tomography (EBT) facility for CAC screening. Multivariate logistic regression was used to test the association between increasing quartiles of lipid levels and presence of CAC score (CACS) > 0 and CACS ≥ 100, with the lowest levels (first quartile) of lipid values as reference.ResultsOverall CACS of 0, 1–99, 100–399 and ≥400, were observed in 35%, 44%, 12% and 9% of the study subjects, respectively. The prevalence of CAC increased significantly across increasing quartiles of LDL-C, TG and Non-HDL-C (all p < 0.0001), whereas CACS was significantly lower across increasing quartiles of HDL-C (p < 0.001). In a multivariate model controlling for age, gender, race, cigarette smoking, hypertension, family history of coronary artery disease and obesity, there was a significant increase in the prevalence of CAC with increasing values of each lipid variable. In a multivariate model simultaneously controlling for increasing quartiles of the remaining lipid variables, only the association of Non-HDL-C with CACS > 0 remained statistically significant (p = 0.002). Similar results were observed with CACS ≥ 100 (p = 0.038).ConclusionIn this study Non-HDL-C was more strongly associated with subclinical atherosclerosis than all other conventional lipid values. These data suggests that Non-HDL-C may be an important treatment target in primary prevention.     

Engineering Properties of Waste Sawdust-Based Lightweight Alkali-Activated Concrete: Experimental Assessment and Numerical Prediction

Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.     

Rate of Seroconversion in Repeat Blood Donors at The National Blood Centre,Kuala Lumpur

The World Health Organization (WHO) recommend that all donated blood are to be screened for at least three viral infections [human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV)]. The National Blood Centre, Kuala Lumpur (NBCKL) aims to reduce transfusion transmitted infections (TTI) as it still remains as one of the major risk for blood transfusion. A cross sectional study was conducted at the National Blood Centre, Kuala Lumpur from 1st January 2009 to 31st June 2010. Data from 581,020 donors were analyzed from year 2004 to 2008. All data were retrieved from NBCKL Blood Bank Information System (BBIS). A total of 201 repeat donors were included in the study based on the inclusion criteria but only 132 repeat donors agreed to participate. Information on sociodemographic, risk factors, knowledge of donors and high risk behavior were extracted from standardize questionnaire. Data were analyzed using SPSS version 14.0. The aim of this study was to determine the predictors of the seropositive infectivity among repeat blood donors at the NBCKL. The results showed Syphilis accounts for the highest and increasing seroconversion rate among other infections from 20.83 % in year 2004 to 44.6 % in year in year 2008. HIV and HCV infection also showed increasing seroconversion rate in 5 years’ time from 6.41 % in year 2004 to 17.54 % in year 2008 and 4.8 % in year 2004 to 5.94 % in year 2008 respectively. However, HBV infection alone showed a decreasing seroconversion rate from 20.83 % in year 2004 to 10.4 % in year 2008. Level of donors’ awareness regarding high risk factors (activities or behaviour) can lead to higher risk of TTI with significant p value in this predictors model(p < 0.05). Repeat blood donors with high risk activities are more likely to have seropositive results for HBV, HIV and Syphilis. This study found that the frequency of HCV seropositivity is higher among lapsed donor. Socio demographic factors such as male and working in the private sector predominates in all TTI markers. Majority of the respondents were aware about relation of high risk activities and risk of TTI.     

Hyponatremia as the Initial Presentation of Cryptococcal Meningitis After Liver Transplantation

Introduction:

Meningoencephalitis is the most common clinical manifestation of cryptococcal infection, as the organism has a propensity to invade the CNS. Patients often present with elevated intracranial pressure, focal motor deficits, altered mentation and internal hydrocephalus. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been reported as a notable cause of euvolemic hyponatremia in immunocompromised patients.

Case Presentation:

A 67-year-old male with liver transplantation due to hepatitis C (HCV) related liver cirrhosis developed severe hyponatremia four months after liver transplantation, which was discovered during routine clinic visit. Patient was referred to the emergency department, treated and discharged with normal serum sodium level. Few days later, he presented with dizziness, confusion, ataxia, abnormal muscle movements and leg pain. Laboratory investigations were consistent with SIADH and revealed a sodium level of 115 mmol/L. Brain MRI showed a leptomeningeal enhancement in the superior cerebellar sulci suspicious for infection. Lumbar puncture was performed and consistent with Cryptococcus neoformans infection; therefore, cryptococcal meningitis was diagnosed. Amphotericin B was started for the patient for six weeks followed by fluconazole for one year. His level of consciousness improved significantly, and his serum sodium level slowly returned to its normal baseline over three weeks after starting amphotericin B.

Conclusions:

Symptomatic hyponatremia secondary to SIADH remains a rare complication of cryptococcal meningitis.     

Human neutrophil antigen profiles in Banjar,Bugis, Champa,Jawa and Kelantan Malays in Peninsular Malaysia

Background

Human neutrophil antigens (HNA) are polymorphic and immunogenic proteins involved in the pathogenesis of neonatal alloimmune neutropenia, transfusion-related acute lung injury (TRALI) and transfusion-related alloimmune neutropenia. The characterisation of HNA at a population level is important for predicting the risk of alloimmunisation associated with blood transfusion and gestation and for anthropological studies.

Materials and methods

Blood samples from 192 healthy, unrelated Malays were collected and genotyped using polymerase chain reaction-sequence specific primers (HNA-1, -3, -4) and polymerase chain reaction-restriction fragment length polymorphisms (HNA-5). The group comprised 30 Banjar, 37 Bugis, 51 Champa, 39 Jawa and 35 Kelantan Malays.

Results

The most common HNA alleles in the Malays studied were HNA-1a (0.641–0.765), -3a (0.676–0.867), -4a (0.943–1.000) and -5a (0.529–0.910). According to principal coordinate plots constructed using HNA allele frequencies, the Malay sub-ethnic groups are closely related and grouped together with other Asian populations. The risks of TRALI or neonatal neutropenia were not increased for subjects with HNA-1, -3 and -4 loci even for donor and recipient or pairs from different Malay sub-ethnic groups. Nonetheless, our estimates showed significantly higher risks of HNA alloimmunisation during pregnancy and transfusion between Malays and other genetically differentiated populations such as Africans and Europeans.

Discussion

This study reports HNA allele and genotype frequencies for the five Malay sub-ethnic groups living in Peninsular Malaysia for the first time. These Malay sub-ethnic groups show closer genetic relationships with other Asian populations than with Europeans and Africans. The distributions of HNA alleles in other lineages of people living in Malaysia (e.g. Chinese, Indian and Orang Asli) would be an interesting subject for future study.     

Molecular Characterization of G6PD Deficient Variants in Nineveh Province,Northwestern Iraq

Glucose-6-phosphate dehydrogenase (G6PD) deficiency considered to be the commonest inherited enzymopathies disorders worldwide including Iraq. Studies have addressed its prevalence and molecular characterization in several parts of the country, but no data were available from Nineveh province, northwestern-Iraq regarding molecular basis of this inherited enzymopathy. To determine the molecular basis of G6PD deficient variants in Nineveh province. A total of 61 G6PD deficient male individuals from Nineveh province were enrolled in this study. DNA from all enrolled individuals were extracted and analyzed for four deficient molecular variants using a polymerase chain reaction–restriction fragment polymorphism method. These deficient variants were G6PD-Mediterranean (563 C→T), G6PD-Chatham (1003 G→A), G6PD-A-(202 G→A) and G6PD-Cosenza (1376 G→C). Also enrolled individuals were screened for silent 1311 (C→T) mutation. It was found that 46 (75.41 %) were G6PD-Mediterranean, 1(1.64 %) were G6PD-Chatham, another 1(1.64 %) were G6PD-A-, and 13 (21.31 %) were remained uncharacterized. Also all G6PD-Mediterranean as well as one uncharacterized individuals were carriers of silent 1311 (C→T) mutation. This study documented that G6PD-Mediterranean constitute the bulk of G6PD deficient variants in this province and G6PD-Chatham and A- were encountered less frequently. Also that silent 1311 (C→T) mutation were common among G6PD-Mediterranean deficient variants individuals.