Drug Abuse And Dependence Among Adolescents In Malaysia.

Laporan ini menunjukkan hasil kajian daripada penganalisaan data yang telah dikumpul oleh Sistem Kawalan Penyalahgunaan Dadah Kebangsaan (SKPDK) mengenai penyalahguna dadah golongan muda, dalam lingkungan umur 21 tahun dan ke bawah, di antara tahun 1978 sehingga tahun 1987. Tujuan kajian ini adalah untuk mengkaji mengenai masalah penyalahguna dadah yang berada dalam lingkungan umur 21 tahun dan ke bawah

TEM Study on the Evolution of Ge Nanocrystals in Si Oxide Matrix as a Function of Ge Concentration and the Si Reduction Process

Growth and evolution of germanium (Ge) nanocrystals embedded into a silicon oxide (SiO₂) system have been studied based on the Ge content of co-sputtered Ge-SiO₂ films using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. It was found that when the proportion of Ge relative to Ge oxide is 20%, TEM showed that annealing the samples at 800°C for 60 min resulted in the formation of a denuded region between the silicon/silicon oxide (Si/SiO₂) interface and a band of Ge nanocrystals towards the surface of the film. By introducing a 20nm thick thermal oxide barrier on top of the silicon (Si) substrate on which the film is deposited, no denuded region in the bulk of this sample is observed. It is proposed that this barrier is effective in reducing both Ge diffusion into the Si substrate and Si diffusion from the substrate into the film. Si diffusing from the Si substrate reduces the Ge oxide into Ge which can subsequently diffuse into the Si substrate. However, the oxide barrier is able to confine the Ge within the oxide matrix so that the denuded region in the bulk of the film cannot form. However the reduction in diffusion should be more significant for Ge as its diffusion coefficient is lower than Si due to its larger size. It is suggested that the denuded region consists of amorphous Ge diffusing towards the Si/SiO₂ interface. When the Ge content is increased to slightly more than 70%, TEM showed that Ge nanocrysyals formed after annealing at 800°C for only 30 min for samples with and without the oxide barrier. There is no denuded region between the Ge nanocrystals band and the Si/SiO₂ interface for both samples but it was observed that coarsening effects were more prominent in the film deposited on top of the oxide barrier. The reduction effect of Si on Ge oxide should not play a significant role in these samples as the Ge content is high.Singapore-MIT Alliance (SMA

Application of Pauli-Villars regularization and discretized light-cone quantization to a single-fermion truncation of Yukawa theory

We apply Pauli-Villars regularization and discretized light-cone quantization to the nonperturbative solution of (3+1)-dimensional Yukawa theory in a single-fermion truncation. Three heavy scalars, including two with negative norm, are used to regulate the theory. The matrix eigenvalue problem is solved for the lowest-mass state with use of a new, indefinite-metric Lanczos algorithm. Various observables are extracted from the wave functions, including average multiplicities and average momenta of constituents, structure functions, and a form factor slope.Comment: 21 pages, 7 figures, RevTeX; published version: more extensive data in the tables of v

Analysis of shared heritability in common disorders of the brain

ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

A delayed payment method in co-ordinating a single-vendor multi-buyer supply chain

In this paper, we consider a co-ordinated single-vendor multi-buyer supply chain model by synchronizing ordering and production cycles with delayed payments that are based on the buyers' order intervals. It can be shown that the synchronized cycles policy works better, in terms of total system costs, than independent optimization. While the vendor is benefited from the co-ordination by synchronized cycles, this research proposes a co-ordination mechanism that incorporates a delayed payment method which can guarantee that a buyer's total relevant cost of co-ordination will not be increased when compared with independent optimization. Most importantly, the vendor does not require any cost information from the buyers when applying this co-ordination mechanism.Synchronization Cost sharing Multiple buyers Delayed payment

Effects of native human zona pellucida glycoproteins 3 and 4 on acrosome reaction and zona pellucida binding of human spermatozoa

Acrosome reaction is crucial to the penetration of spermatozoa through the zona pellucida (ZP). Glycosylation of ZP glycoproteins is important in spermatozoa-ZP interaction. Human ZP glycoprotein-3 (ZP3) is believed to initiate acrosome reaction. Recently, human ZP4 was also implicated in inducing acrosome reaction. These studies were based on recombinant human ZP proteins with glycosylation different from their native counterparts. In the present study, the effects of native human ZP3 and ZP4 on acrosome reaction and spermatozoa-ZP binding were investigated. Native human ZP3 and ZP4 were immunoaffinity-purified. They induced acrosome reaction and inhibited spermatozoa-ZP binding time- and dose-dependently to different extents. These biological activities of human ZP3 and ZP4 depended partly on their glycosylation, with N-linked glycosylation contributing much more significantly than O-linked glycosylation. Studies with inhibitors showed that both human ZP3- and ZP4-induced acrosome reactions were protein kinase-C, protein tyrosine kinase, T-type Ca2+ channels, and extracellular Ca2+ dependent. G-protein also participated in human ZP3- but not in ZP4-induced acrosome reaction. On the other hand, protein kinase-A and L-type Ca 2+ channels took part only in human ZP4-induced acrosome reaction. This manuscript describes for the first time the actions of purified native human ZP3 and ZP4 on acrosome reaction and spermatozoa-ZP binding. © 2008 by the Society for the Study of Reproduction, Inc.link_to_subscribed_fulltex

Derivation of a prognostic score for identifying critically ill patients in an emergency department resuscitation room

Introduction Several prognostic scores exist for critically ill patients, including APACHE II, Revised Trauma Score (RTS), Rapid Emergency Medicine Score (REMS) and Modified Early Warning Score (MEWS). However, there is no widely used score specifically designed to predict the likelihood of early intensive care unit (ICU) admission or death in undifferentiated emergency department (ED) resuscitation room patients. We aimed to derive such a score and compare it with other similar scores. Methods This was a single centre study of consecutive adult resuscitation room patients over one month. Physiological and blood test variables were compared according to the composite primary outcome: admission to ICU or death within 7 days of attendance. Multivariate logistic regression was used to derive a prediction score which was compared with other scores using ROC (receiver operating characteristic) analysis. Results 330 patients were included in the study, of whom 77 were admitted to ICU or died within 7 days. A prediction score was derived using the following parameters: systolic blood pressure; Glasgow coma score; blood glucose; bicarbonate; white cell count; and a history of metastates. This score significantly out-performed APACHE II, RTS, REMS and MEWS with an area under the ROC curve of 0.909 (95% CI 0.872–0.938). Conclusion The Prince of Wales Emergency Department Score (PEDS) is a new prognostic score to predict the likelihood of early ICU admission or death in undifferentiated resuscitation room patients. Further studies are needed to validate and refine this potentially useful tool