Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin throughhole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183∘C)

Characteristics of alternating current conductivity in ternary zinc calcium phosphate glasses.

Binary (CaO)x(P2O5)1−x glasses with mole fraction x=0.05–0.4 with an interval of 0.05 and ternary (ZnO)x(CaO)0.3−x(P2O5)0.7 glasses with mole fraction x=0.01–0.09 with an interval of 0.02 were synthesized by the melt quenching technique over a wide composition range. The electrical properties of these glasses were investigated by ac impedance spectroscopy from 10 to 1 MHz for temperatures ranging from room temperature to 300°C. The conductivity of both samples shows dispersive behavior at lower temperatures, while at higher temperatures the conductivity is almost constant at the lower end of the frequency, approaching the dc conductivity limit and rises rapidly as the frequency is increased. We also observed that the onset of the dispersion shifted to higher frequencies with the increase in temperature. The dc conductivity (σdc) was found to increase with higher temperatures. The activation energy for electrical conduction, Eσ and activation energy for electrical relaxation, Eτ for (ZnO)x (CaO)0.3−x (P2O5)0.7 were found to be slightly higher than (CaO)x (P2O5)1−x. Observations of the dielectric strength, Δɛ, of (ZnO)x (CaO)0.3−x (P2O5)0.7 glasses showed that Δɛ increased with the increase of ZnO

Self-assembly of quantum dots: effect of neighbor islands on the wetting in coherent Stranski-Krastanov growth

The wetting of the homogeneously strained wetting layer by dislocation-free three-dimensional islands belonging to an array has been studied. The array has been simulated as a chain of islands in 1+1 dimensions. It is found that the wetting depends on the density of the array, the size distribution and the shape of the neighbor islands. Implications for the self-assembly of quantum dots grown in the coherent Stranski-Krastanov mode are discussed.Comment: 4 pages, 6 figures, accepted version, minor change

A metabolite-derived protein modification integrates glycolysis with KEAP1-NRF2 signalling.

Mechanisms that integrate the metabolic state of a cell with regulatory pathways are necessary to maintain cellular homeostasis. Endogenous, intrinsically reactive metabolites can form functional, covalent modifications on proteins without the aid of enzymes1,2, and regulate cellular functions such as metabolism3-5 and transcription6. An important 'sensor' protein that captures specific metabolic information and transforms it into an appropriate response is KEAP1, which contains reactive cysteine residues that collectively act as an electrophile sensor tuned to respond to reactive species resulting from endogenous and xenobiotic molecules. Covalent modification of KEAP1 results in reduced ubiquitination and the accumulation of NRF27,8, which then initiates the transcription of cytoprotective genes at antioxidant-response element loci. Here we identify a small-molecule inhibitor of the glycolytic enzyme PGK1, and reveal a direct link between glycolysis and NRF2 signalling. Inhibition of PGK1 results in accumulation of the reactive metabolite methylglyoxal, which selectively modifies KEAP1 to form a methylimidazole crosslink between proximal cysteine and arginine residues (MICA). This posttranslational modification results in the dimerization of KEAP1, the accumulation of NRF2 and activation of the NRF2 transcriptional program. These results demonstrate the existence of direct inter-pathway communication between glycolysis and the KEAP1-NRF2 transcriptional axis, provide insight into the metabolic regulation of the cellular stress response, and suggest a therapeutic strategy for controlling the cytoprotective antioxidant response in several human diseases

The prevalence of hypertension among Malaysian adults and its associated risk factors: data from Malaysian Community Salt Study (MyCoSS)

Background Hypertension is one of the most common risk factors for cardiovascular disease and leading cause of mortality globally. The aims of this study were to assess the prevalence of hypertension and its associated risk factors among Malaysian population using data from the Malaysian Community Salt Study (MyCoSS). Methods This study was a cross-sectional study using multi-stage stratified sampling method. Data collection was carried out via face-to-face interview at the respondent’s home from October 2017 until March 2018. A total of 1047 respondents aged 18 years and above completed the questionnaires and blood pressure measurement. A person who reported diagnosis of hypertension by a physician and had systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg on three readings was categorised as hypertensive. Risk factors of hypertension were analysed using multiple logistic regression. Results The prevalence of hypertension in the present study was 49.39% (95% CI 44.27–54.51). There was no statistically significant difference in gender. Age, household income, BMI, and diabetes were significantly associated with hypertension. Hypertension found had inverse association with the level of education. Age was the strongest predictor of hypertension (35–44 years old; OR=2.39, 95% CI=1.39–4.09, 45–54 years old; OR=5.50, 95% CI=3.23–9.38, 55–64 years old OR=13.56, 95% CI=7.77–23.64 and 65 years old and above; OR=25.28, 95% CI=13.33–48.66). Those who had higher BMI more likely to be hypertensive as compared to respondents with normal weight (overweight, OR=1.84; 95% CI=1.18–2.86; obese, OR=4.29% CI=2.56–7.29). Conclusion The findings showed that hypertension is prevalent among adults in Malaysia. Those with older age, higher BMI, and diabetes are more likely to have hypertension. Efforts regarding lifestyle modification and education could be important in hypertension management and prevention

Microwave Dielectric and Reflection Characterization on Silver Grunter (Pomadasys hasta) and Tilapia (Oreochromisniloticus) Fish Scale for Potential Use as Scaffold

Hydroxyapatite from fish scale was studied and reported of its potential in bone scaffold or regenerative material. Fish scale as a source of collagen and valuable matrix proteins in the pharmaceutical and cosmetic industries is overwhelmingly studied among researchers. In this work, dielectric and reflection measurement was conducted on fish scale from Silver Grunter (Pomadasys hasta) and Tilapia (Oreochromisniloticus) fish ranging from 200 MHz to 20 GHz using Agilent E8362B PNA Network Analyzer in conjunction with an Agilent 85070E High Temperature Probe. The fish scale was prepared as sample under test prior to measurements. Dielectric constant, and loss factor increase with frequency. Meanwhile, the measured magnitude and phase of reflection coefficient that acquired through reflection measurement decrease when frequency increases. On the other hand, both fish scales were characterized as crystalline structure via X-ray diffraction analysis. It is important in analyzing dielectric mechanism occurs in fish scale

Equitable and Effective Climate Policy: Integrating Less Developed Countries into a Global Climate Agreement

ISSN:1612-4804ISSN:1612-481

Structural Insights into TIR Domain Specificity of the Bridging Adaptor Mal in TLR4 Signaling

MyD88 adaptor-like protein (Mal) is a crucial adaptor that acts as a bridge to recruit the MyD88 molecule to activated TLR4 receptors in response to invading pathogens. The specific assembly of the Toll/interleukin-1 receptor (TIR) domains of TLR4, Mal and MyD88 is responsible for proper signal transduction in the TLR4 signaling pathway. However, the molecular mechanism for the specificity of these TIR domains remains unclear. Here, we present the crystal structure of the TIR domain of the human Mal molecule (Mal-TIR) at a resolution of 2.4 Å. Unexpectedly, Mal-TIR exhibits an extraordinarily long AB loop, but no αB helix or BB loop, distinguishing it from other TIR domains. More importantly, the Mal-TIR AB loop is capable of mediating direct binding to the TIR domains of TLR4 and MyD88 simultaneously. We also found that Mal-TIR can form a back-to-back dimer that may resemble the dimeric assembly of the entire Mal molecule. Our data demonstrate the bridge role of the Mal-TIR domain and provide important information about TIR domain specificity

Defining the Boundaries of Normal Thrombin Generation: Investigations into Hemostasis

In terms of its soluble precursors, the coagulation proteome varies quantitatively among apparently healthy individuals. The significance of this variability remains obscure, in part because it is the backdrop against which the hemostatic consequences of more dramatic composition differences are studied. In this study we have defined the consequences of normal range variation of components of the coagulation proteome by using a mechanism-based computational approach that translates coagulation factor concentration data into a representation of an individual's thrombin generation potential. A novel graphical method is used to integrate standard measures that characterize thrombin generation in both empirical and computational models (e.g max rate, max level, total thrombin, time to 2 nM thrombin (“clot time”)) to visualize how normal range variation in coagulation factors results in unique thrombin generation phenotypes. Unique ensembles of the 8 coagulation factors encompassing the limits of normal range variation were used as initial conditions for the computational modeling, each ensemble representing “an individual” in a theoretical healthy population. These “individuals” with unremarkable proteome composition was then compared to actual normal and “abnormal” individuals, i.e. factor ensembles measured in apparently healthy individuals, actual coagulopathic individuals or artificially constructed factor ensembles representing individuals with specific factor deficiencies. A sensitivity analysis was performed to rank either individual factors or all possible pairs of factors in terms of their contribution to the overall distribution of thrombin generation phenotypes. Key findings of these analyses include: normal range variation of coagulation factors yields thrombin generation phenotypes indistinguishable from individuals with some, but not all, coagulopathies examined; coordinate variation of certain pairs of factors within their normal ranges disproportionately results in extreme thrombin generation phenotypes, implying that measurement of a smaller set of factors may be sufficient to identify individuals with aberrant thrombin generation potential despite normal coagulation proteome composition

In silico transcriptional regulation and functional analysis of dengue shock syndrome associated SNPs in PLCE1 and MICB genes

YesSingle nucleotide polymorphisms (SNPs) in PLCE1 and MICB genes increase risk for the development of dengue shock syndrome (DSS). We used Bioinformatics tools to predict alterations at the transcriptional and posttranslational levels driven by PLCE1 and MICB SNPs associated with DSS. Functional and phenotypic analysis conducted to determine deleterious SNPs and impact of amino acid substitution on the structure and function of proteins identified rs2274223 (H1619R) as deleterious to protein coding as it induces structural change in the C2 domain of PLCε, with the mutant residue more positively charged than the wild-type residue (RMSD score, 1.75 Å).Moreover, rs2274223 condenses the chromatinrepressing PLCε expression in DSS. Briefly, this study presents the impact of a single nucleotide transition at SNPs associated with DSS on differential protein binding patterns with PLCE1 and MICB genes and on protein structure modification and their possible role in the pathogenesis of DSS