Thermally Enhanced Stacked Inductor Design for Voltage Regulator Modules

ASIC power requirements have gone up exponentially due to the demand from IoT computing, AI and big data. The VRM (Voltage regulator module) needs to have high power capabilities and efficiency in order to satisfy the TDP (Thermal Design Power) requirement. High peak power operation mode, has also become an industry practice to improve the ASIC instantaneous throughput. This requires more phase count to support the peak current needed during transient. ASIC chips have also increased in size due to the higher pin count for HSIO (High Speed I/O) and interconnects. In order to fit within the limited VRM placement area, a higher power density VRM design is required. In order to minimize the VRM solution size, and keep good thermal performances, a stacked inductor with a thermal band wrapped around to make contact with the Power Stage (Driver MOS) underneath is introduced. This solves both the space issue and thermal problems from a conventional stacked inductor design. The thermal band, can be either assembled during the inductor manufacturing stage, or can be clipped on to a regular inductor before the SMT stage. This provides a cost effective, reliable and compact VRM structure. Simulation and test results are verified the effectiveness of the proposed structure

Ab initio molecular dynamics simulations of Aluminum solvation

The solvation of Al and its hydrolyzed species in water clusters has been studied by means of ab initio molecular dynamics simulations. The hexa-hydrate aluminum ion formed a stable complex in the finite temperature cluster simulation of one aluminum ion and 16 waters. The average dipole moment of strongly polarized hydrated water molecules in the first solvation shell of the hexa-hydrate aluminum ion was found to be 5.02 Debye. The deprotonated hexa-hydrate complex evolves into a tetra-coordinated aluminate ion with two water molecules in the second solvation shell forming hydrogen bonds to the hydroxyl groups in agreement with the observed coordination.Comment: 12 pages in Elsevier LaTeX, 5 figures in Postscript, 2 last figures are in color, submitted to Chemical Physics Letter

Assessment of the humification degree of peat soil under sago (Metroxylon sagu) cultivation based on Fourier Transform Infrared (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopic characteristics

Sago palm (Metroxylon sagu) is a tropical crop that can survive the acidic conditions of peat soil, which is cultivated at large scale in Sarawak (Malaysia). The performance of sago palm on deep peat is variable, and not all specimens are able to grow to maturity and produce a trunk. It is hypothesised that sago growth may be influenced by peat humification because a positive relationship between the fertility of peat soil and its degree of humification has been well reported. This article investigates the humification degree of peat soil used for cultivation of sago palms, as indicated by spectroscopic characteristics. The peat soil adjacent to trunking and non-trunking palms was sampled and compared with exposed uncultivated peat. The results showed that, where largely undecomposed woody material predominated in the underlying peat, degree of humification decreased with increasing depth. Uncultivated peat was more highly humified than cultivated peat because the latter was continuously replenished with new plant matter. On the basis of FTIR spectroscopy, no significant difference was found between cultivated peat sampled adjacent to trunking and non-trunking palms. On the other hand, the UV-Vis and FTIR data suggested lower humification degree in the underlying peat which may have led to inconsistent growth

Spatial heterogeneity and peptide availability determine CTL killing efficiency in vivo

The rate at which a cytotoxic T lymphocyte (CTL) can survey for infected cells is a key ingredient of models of vertebrate immune responses to intracellular pathogens. Estimates have been obtained using in vivo cytotoxicity assays in which peptide-pulsed splenocytes are killed by CTL in the spleens of immunised mice. However the spleen is a heterogeneous environment and splenocytes comprise multiple cell types. Are some cell types intrinsically more susceptible to lysis than others? Quantitatively, what impacts are made by the spatial distribution of targets and effectors, and the level of peptide-MHC on the target cell surface? To address these questions we revisited the splenocyte killing assay, using CTL specific for an epitope of influenza virus. We found that at the cell population level T cell targets were killed more rapidly than B cells. Using modeling, quantitative imaging and in vitro killing assays we conclude that this difference in vivo likely reflects different migratory patterns of targets within the spleen and a heterogeneous distribution of CTL, with no detectable difference in the intrinsic susceptibilities of the two populations to lysis. Modeling of the stages involved in the detection and killing of peptide-pulsed targets in vitro revealed that peptide dose influenced the ability of CTL to form conjugates with targets but had no detectable effect on the probability that conjugation resulted in lysis, and that T cell targets took longer to lyse than B cells. We also infer that incomplete killing in vivo of cells pulsed with low doses of peptide may be due to a combination of heterogeneity in peptide uptake and the dissociation, but not internalisation, of peptide-MHC complexes. Our analyses demonstrate how population-averaged parameters in models of immune responses can be dissected to account for both spatial and cellular heterogeneity

Widespread pandemic, wide-ranging response: student-led virtual telemedicine and digital community-based healthcare provision in a university healthcare Centre in response to coronavirus quarantine measures

Introduction: Isolation and border control measures, with home quarantine measures, are essential to stem the spread of the newly emergent novel Covid-19. Such measures are doomed to fail if reliant on traditional isolation methods, which entail small numbers of overworked healthcare staff screening and surveilling large numbers of well individuals who are potential false positives. Innovative method employed by Hospital UMS to overcome these logistics difficulties. Methods: A total of 440 returning China students to UMS were planned for home quarantine measures for 14 days. In the intervening 14 days, groups of ten quarantined individuals were assigned to 1 Manda¬rin-speaking medical student liaison officer (LO). LOs performed assessment toolkit for 14 consecutive days virtually via WhatsApp and WeChat and reported back to NCOV central command if any symptoms ensued. Results: 45 China students have been put on home quarantine. Two (2) students with symptoms were monitored virtually till resolution of symptoms. Also, five (5) students with uncontactable phone numbers required tracking down, using var¬ious methods eg: retrieval from close contacts through wide-bore virtual search. No cases so far have been positive for NCOV or have required referral to tertiary hospitals. Qualitatively, such methods are a vital public health inter¬vention, as task shifting happens to semi-professionals. Hospital UMS first trial of two cherished founding principles: community-based rather than healthcare-facility center healthcare delivery, and judicious use of digital health com¬munications, applications, and rudimentary telemedicine. Conclusion: Student-led virtual telemedicine and digital health delivery has potential in public health crises like NCOV, freeing frontline healthcare staff to devote energies to their specialties of screening and treatment. Integration of video and biometrics to incorporate true telemedicine, allowing individuals to be “hospitalized” in a community setting in situations of low risk

A Comparison of Assays for Accurate Copy Number Measurement of the Low-Affinity Fc Gamma Receptor Genes FCGR3A and FCGR3B

The FCGR3 locus encoding the low affinity activating receptor FcγRIII, plays a vital role in immunity triggered by cellular effector and regulatory functions. Copy number of the genes FCGR3A and FCGR3B has previously been reported to affect susceptibility to several autoimmune diseases and chronic inflammatory conditions. However, such genetic association studies often yield inconsistent results; hence require assays that are robust with low error rate. We investigated the accuracy and efficiency in estimating FCGR3 CNV by comparing Sequenom MassARRAY and paralogue ratio test-restriction enzyme digest variant ratio (RT-REDVR). In addition, since many genetic association studies of FCGR3B CNV were carried out using real-time quantitative PCR, we have also included the evaluation of that method’s performance in estimating the multi-allelic CNV of FCGR3B. The qPCR assay exhibited a considerably broader distribution of signal intensity, potentially introducing error in estimation of copy number and higher false positive rates. Both Sequenom and PRT-REDVR showed lesser systematic bias, but Sequenom skewed towards copy number normal (CN = 2). The discrepancy between Sequenom and PRT-REDVR might be attributed either to batch effects noise in individual measurements. Our study suggests that PRT-REDVR is more robust and accurate in genotyping the CNV of FCGR3, but highlights the needs of multiple independent assays for extensive validation when performing a genetic association study with multi-allelic CNVs

Tissue Specific Deletion of Inhibitor of Kappa B Kinase 2 with OX40-Cre Reveals the Unanticipated Expression from the OX40 Locus in Skin Epidermis

NF-κB signalling plays an essential role in T cell activation and generation of regulatory and memory populations in vivo. In the present study, we aimed to investigate the role of NF-κB signalling in post-activation T cells using tissue specific ablation of inhibitor of kappa-B kinase 2 expression, an important component of the inhibitor of kappa-B kinase complex in canonical NF-κB signalling. The OX40 antigen is expressed on activated T cells. Therefore, we used previously described mouse strain expressing Cre recombinase from the endogenous OX40 locus. Ablation of IKK2 expression using OX40Cre mice resulted in the development of an inflammatory response in the skin epidermis causing wide spread skin lesions. The inflammatory response was characterised by extensive leukocytic infiltrate in skin tissue, hyperplasia of draining lymph nodes and widespread activation in the T cell compartment. Surprisingly, disease development did not depend on T cells but was rather associated with an unanticipated expression of Cre in skin epidermis, and activation of the T cell compartment did not require Ikbk2 deletion in T cells. Employment of Cre reporter strains revealed extensive Cre activity in skin epidermis. Therefore, development of skin lesions was rather more likely explained by deletion of Ikbk2 in skin keratinocytes in OX40Cre mice

High Diversity of Cryptosporidium Subgenotypes Identified in Malaysian HIV/AIDS Individuals Targeting gp60 Gene

BACKGROUND: Currently, there is a lack of vital information in the genetic makeup of Cryptosporidium especially in developing countries. The present study aimed at determining the genotypes and subgenotypes of Cryptosporidium in hospitalized Malaysian human immunodeficiency virus (HIV) positive patients. METHODOLOGY/PRINCIPAL FINDINGS: In this study, 346 faecal samples collected from Malaysian HIV positive patients were genetically analysed via PCR targeting the 60 kDa glycoprotein (gp60) gene. Eighteen (5.2% of 346) isolates were determined as Cryptosporidium positive with 72.2% (of 18) identified as Cryptosporidium parvum whilst 27.7% as Cryptosporidium hominis. Further gp60 analysis revealed C. parvum belonging to subgenotypes IIaA13G1R1 (2 isolates), IIaA13G2R1 (2 isolates), IIaA14G2R1 (3 isolates), IIaA15G2R1 (5 isolates) and IIdA15G1R1 (1 isolate). C. hominis was represented by subgenotypes IaA14R1 (2 isolates), IaA18R1 (1 isolate) and IbA10G2R2 (2 isolates). CONCLUSIONS/SIGNIFICANCE: These findings highlighted the presence of high diversity of Cryptosporidium subgenotypes among Malaysian HIV infected individuals. The predominance of the C. parvum subgenotypes signified the possibility of zoonotic as well as anthroponotic transmissions of cryptosporidiosis in HIV infected individuals

A de novo transcriptome of the Asian tiger mosquito, Aedes albopictus, to identify candidate transcripts for diapause preparation

<p>Abstract</p> <p>Background</p> <p>Many temperate insects survive the harsh conditions of winter by undergoing photoperiodic diapause, a pre-programmed developmental arrest initiated by short day lengths. Despite the well-established ecological significance of photoperiodic diapause, the molecular basis of this crucial adaptation remains largely unresolved. The Asian tiger mosquito, <it>Aedes albopictus </it>(Skuse), represents an outstanding emerging model to investigate the molecular basis of photoperiodic diapause in a well-defined ecological and evolutionary context. <it>Ae. albopictus </it>is a medically significant vector and is currently considered the most invasive mosquito in the world. Traits related to diapause appear to be important factors contributing to the rapid spread of this mosquito. To generate novel sequence information for this species, as well as to discover transcripts involved in diapause preparation, we sequenced the transcriptome of <it>Ae. albopictus </it>oocytes destined to become diapausing or non-diapausing pharate larvae.</p> <p>Results</p> <p>454 GS-FLX transcriptome sequencing yielded >1.1 million quality-filtered reads, which we assembled into 69,474 contigs (N50 = 1,009 bp). Our contig filtering approach, where we took advantage of strong sequence similarity to the fully sequenced genome of <it>Aedes aegypti</it>, as well as other reference organisms, resulted in 11,561 high-quality, conservative ESTs. Differential expression estimates based on normalized read counts revealed 57 genes with higher expression, and 257 with lower expression under diapause-inducing conditions. Analysis of expression by qPCR for 47 of these genes indicated a high correlation of expression levels between 454 sequence data and qPCR, but congruence of statistically significant differential expression was low. Seven genes identified as differentially expressed based on qPCR have putative functions that are consistent with the insect diapause syndrome; three genes have unknown function and represent novel candidates for the transcriptional basis of diapause.</p> <p>Conclusions</p> <p>Our transcriptome database provides a rich resource for the comparative genomics and functional genetics of <it>Ae. albopictus</it>, an invasive and medically important mosquito. Additionally, the identification of differentially expressed transcripts related to diapause enriches the limited knowledge base for the molecular basis of insect diapause, in particular for the preparatory stage. Finally, our analysis illustrates a useful approach that draws from a closely related reference genome to generate high-confidence ESTs in a non-model organism.</p