ZnO nanorod/GaN light-emitting diodes: The origin of yellow and violet emission bands under reverse and forward bias

ZnO nanorods have been prepared by electrodeposition under identical conditions on various p-GaN-based thin film structures. The devices exhibited lighting up under both forward and reverse biases, but the turn-on voltage and the emission color were strongly dependent on the p-GaN-based structure used. The origin of different luminescence peaks under forward and reverse bias has been studied by comparing the devices with and without ZnO and by photoluminescence and cathodoluminescence spectroscopy. We found that both yellow-orange emission under reverse bias and violet emission under forward bias, which are commonly attributed to ZnO, actually originate from the p-GaN substrate and/or surface/interface defects. While the absolute brightness of devices without InGaN multiple quantum wells was low, high brightness with luminance exceeding 10 000 cd/m 2 and tunable emission (from orange at 2.1 V to blue at 2.7 V, with nearly white emission with Commission internationale de l'éclairage (CIE) coordinates (0.30, 0.31) achieved at 2.5 V) was obtained for different devices containing InGaN multiple quantum wells. © 2011 American Institute of Physics.published_or_final_versio

Revealing the story of an orphan drug: clofazimine speciation and solubilization as a function of pH

Since the introduction of combinatorial chemistry and high-throughput screening in drug discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo complicated reactions in aqueous solution, such as forming precipitates or complexes with buffer species or undergoing self-aggregation (dimer, trimer, etc.)1,2 or micelle formations. Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, determined by a suitable method. In a pH-dependent measurement of a property (e.g. solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of measured values, but paradoxically, such preference can lead to inaccurate rationalization of the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, the use of calculated pKas can substantially wrench the interpretation of solution properties. Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 40 years, exhibits some of the properties of relatively recent drug molecules by being extremely water insoluble and having variable pKa values reported. We have recently combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to water, the dimer would be more water soluble than the monomeric free base. In saturated solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount importance for understanding of CFZ speciation and the future progress in developing its improved formulations which is the subject of our ongoing studies

Revealing the story of an orphan drug: clofazimine speciation and solubilization as a function of pH

Since the introduction of combinatorial chemistry and high-throughput screening in drug discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo complicated reactions in aqueous solution, such as forming precipitates or complexes with buffer species or undergoing self-aggregation (dimer, trimer, etc.) or micelle formations. Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, determined by a suitable method. In a pH-dependent measurement of a property (e.g. solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of measured values, but paradoxically, such preference can lead to inaccurate rationalization of the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, the use of calculated pKas can substantially wrench the interpretation of solution properties. Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 40 years, exhibits some of the properties of relatively recent drug molecules by being extremely water insoluble and having variable pKa values reported. We have recently combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to water, the dimer would be more water soluble than the monomeric free base. In saturated solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount importance for understanding of CFZ speciation and the future progress in developing its improved formulations which is the subject of our ongoing studies

Laboratory Diagnosis of SARS

The virologic test results of 415 patients with severe acute respiratory syndrome (SARS) were examined. The peak detection rate for SARS-associated coronavirus occurred at week 2 after illness onset for respiratory specimens, at weeks 2 to 3 for stool or rectal swab specimens, and at week 4 for urine specimens. The latest stool sample that was positive by reverse transcription–polymerase chain reaction (RT-PCR) was collected on day 75 while the patient was receiving intensive care. Tracheal aspirate and stool samples had a higher diagnostic yield (RT-PCR average positive rate for first 2 weeks: 66.7% and 56.5%, respectively). Pooled throat and nasal swabs, rectal swab, nasal swab, throat swab, and nasopharyngeal aspirate specimens provided a moderate yield (29.7%–40.0%), whereas throat washing and urine specimens showed a lower yield (17.3% and 4.5%). The collection procedures for stool and pooled nasal and throat swab specimens were the least likely to transmit infection, and the combination gave the highest yield for coronavirus detection by RT-PCR. Positive virologic test results in patient groups were associated with mechanical ventilation or death (p < 0.001), suggesting a correlation between viral load and disease severity

Hsa-miRNA-765 as a key mediator for inhibiting growth, migration and invasion in fulvestrant-treated prostate cancer

Fulvestrant (ICI-182,780) has recently been shown to effectively suppress prostate cancer cell growth in vitro and in vivo. But it is unclear whether microRNAs play a role in regulating oncogene expression in fulvestrant-treated prostate cancer. Here, this study reports hsa-miR-765 as the first fulvestrant-driven, ERβ-regulated miRNA exhibiting significant tumor suppressor activities like fulvestrant, against prostate cancer cell growth via blockage of cell-cycle progression at the G2/M transition, and cell migration and invasion possibly via reduction of filopodia/intense stress-fiber formation. Fulvestrant was shown to upregulate hsa-miR-765 expression through recruitment of ERβ to the 5′-regulatory-region of hsa-miR-765. HMGA1, an oncogenic protein in prostate cancer, was identified as a downstream target of hsa-miR-765 and fulvestrant in cell-based experiments and a clinical study. Both the antiestrogen and the hsa-miR-765 mimic suppressed HMGA1 protein expression. In a neo-adjuvant study, levels of hsa-miR-765 were increased and HMGA1 expression was almost completely lost in prostate cancer specimens from patients treated with a single dose (250 mg) of fulvestrant 28 days before prostatectomy. These findings reveal a novel fulvestrant signaling cascade involving ERβ-mediated transcriptional upregulation of hsa-miR-765 that suppresses HMGA1 protein expression as part of the mechanism underlying the tumor suppressor action of fulvestrant in prostate cancer. © 2014 Leung et al

Multiple Gene Polymorphisms in the Complement Factor H Gene Are Associated with Exudative Age-Related Macular Degeneration in Chinese

PURPOSE. Variants in the complement factor H (CFH) gene have been shown to be strongly associated with age-related macular degeneration (AMD). In this study, sequence alterations in CFH were investigated in 163 Chinese patients with exudative AMD and 155 unrelated Chinese control subjects. METHODS. All the 22 CFH exons, intron-exon boundaries, and promoter sequences were screened by polymerase chain reaction and DNA sequencing. RESULTS. Fifty-eight sequence changes, 42 of them novel, were identified. Six SNPs with an allele frequency Ͼ30% were significantly associated with exudative AMD. SNP rs3753396 was novel; the rest had been reported: rs3753394, rs551397, rs800292, rs2274700, and rs1329428. Two haplotype blocks were constructed. The TG haplotype for rs551397 and rs800292 was the major haplotype that conferred a significantly increased susceptibility to exudative AMD (P corr ϭ 0.0001, OR ϭ 1.91, 95% CI ϭ 1.36 -2.68). CONCLUSIONS. The findings support prior evidence that the CFH gene is one of the AMD-associated genes. There is a different distribution pattern of CFH variants in the Chinese compared with other populations. Individual SNP and haplotype analyses revealed that the ancient alleles at the 5Ј end of CFH contribute to an increased susceptibility to exudative AMD. (Invest Ophthalmol Vis Sci. 2008;49:3312-3317) DOI:10.1167/iovs.07-1517 A ge-related macular degeneration (AMD; MIM 603075; Mendelian Inheritance in Man) is a major cause of irreversible visual impairment and blindness in people older than 65 years in developed countries. 1,2 The occurrence of AMD is pan ethnic, and a high prevalence AMD has been reported in the elderly Chinese population. 5 Therefore, a greater understanding of the primary pathophysiology is needed to advance treatment and preventive measures. The etiology of AMD is complex and multifactorial, probably resulting from interactions between environmental and multigenetic factors. 6 Genetic association studies have revealed that single nucleotide polymorphisms (SNPs) in the complement factor H gene (CFH; MIM 134370; e.g., Tyr402His) are significantly associated with susceptibility to AMD. 25 A fine-scale linkage disequilibrium mapping of AMD in the CFH region detected a point location of a causal variant between exons 1 and 2 of CFH other than exon 9 for Tyr402His. MATERIALS AND METHODS Patients and Control Subjects 21 Also recruited and given complete ophthalmic examinations were 155 unrelated control subjects, 72 men and 83 women ranging in age at recruitment from 60 to 99 years (mean Ϯ SD, 73.1 Ϯ 6.5 years). They matched the patients by age and gender and had no sign of AMD or other eye diseases, except mild myopia or senile cataract. The study protocol was approved by the Ethics Committee on Human Research, the Chinese University of Hong Kong. All the procedures used conformed to the tenets of the Declaration of Helsinki. Informed consent was obtained from all study subjects after explanation of the nature of the study. Sample Collection, PCR Amplification, DNA Sequencing, and SNP Genotyping Venous blood was obtained from each study subject, and genomic DNA was extracted with a DNA blood kit (QIAamp; Qiagen, Hilden, Germany). The promoter sequence up to Ϫ867 upstream and all coding sequences of the CFH gene, including intron-exon boundaries, were screened for sequence alterations. Primers were generated based on the GenBank sequence of CFH (NM_000186.2; http://www.ncbi. nlm.nih.gov/Genbank; provided in the public domain by the National Center for Biotechnology Information, Bethesda, MD). PCR was performed on a thermal cycler (model 9700; Applied Biosystems, Inc. [ABI], Foster City, CA) with optimized protocols 27 Statistical Analysis Hardy-Weinberg equilibrium (HWE) for each polymorphism was tested by 2 test. Allele or genotype frequencies between cases and control subjects were compared by 2 analysis or the Fisher exact test. The odds ratios (ORs) of the alleles and haplotypes were estimated by 2 test (SPSS ver.15.0; SPSS Inc., Chicago, IL). Population attributable risk (PAR) of the risk genotype was calculated with the formula f(R Ϫ 1)/R, where f is the faction of cases with the risk genotype and R is the measure of OR 8 . A pair-wise linkage disequilibrium (LD, DЈ) estimation between polymorphisms with a minor allele frequency (MAF) Ͼ 1%, and EM-based haplotype association analysis were performed with Haploview (ver. 3.32, from http://www.broad.mit.edu/mpg/ haploview/ provided in the public domain by the Broad Institute, Massachusetts Institute of Technology, Cambridge, MA). For multiple comparison, probabilities were corrected by permutation test (iterations, 10,000). Statistical significance was defined as a corrected P (P corr ) Ͻ 0.05. RESULTS CFH Variants in the Study Subjects A total of 58 sequence variations were identified, all of which followed Hardy Weinberg Equilibrium Six of the seven common variants Six SNPs were identified in the promoter, all supported decreased susceptibility to AMD Haplotype Association Analysis LD analysis revealed extension of LD throughout the CFH gene. We included SNPs with MAF Ͼ 5% and two missense changes, rs1061170 (Tyr402His) and Val837Ile, in our haplotype association analysis. Two distinct haplotype blocks were detected The haplotypes H3 and H4, which were defined by all six AMD-associated SNPs, conferred significantly reduced or increased AMD susceptibility (H3: OR ϭ 0.56, 95% CI ϭ 0.39 -0.80; H4: OR ϭ 1.63, 95% CI ϭ 1.19 -2.23). When a G allele of rs1065489 (Asp936Glu) was included in these two haplotypes, the H5, which contained all the alleles in H3, remain significantly associated with the disease (P corr ϭ 0.0012). However, when a G allele or a T allele was added to the H4, the newly constructed H6 and H7 were no longer AMD associated (P corr ϭ 0.052 and 0.177, respectively). We constructed two-allele haplotypes by using rs800292 (Val62Ile) with the uncommon SNPs rs1061170 (Tyr402His) and Val837Ile, to investigate the effects of the minor variants. H10 and H11, containing a T allele of rs1061170 (Tyr402His), remained significantly associated with AMD. However, the haplotypes containing a C allele of rs1061170 DISCUSSION Although the pathogenesis of exudative AMD has not been definitively elucidated, studies in the past few years have revealed important information on its genetic basis. Polymorphisms in the CFH gene have been shown to be AMD associated in different ethnic groups, although there are obvious differences in the occurrence of disease-susceptible SNPs between Caucasian and Oriental populations. 26 mapped a point location for a causal variant between exons 1 and 2, which approximates block 1 in our present study, suggesting that the 5Ј region of the CFH (N-terminal of factor H) is commonly associated with AMD in both Chinese and Caucasians. We found haplotype block 2 spanning a region from exon 10 to intron 15 and containing SNP rs2274700 (Ala473Ala, exon 10), which have recently been shown to have a strong association with AMD in Caucasians and Japanese. Besides the haplotypes in the two haplotype blocks, the haplotypes defined by the six common SNPs (H3, H4) were also significantly associated with exudative AMD. However, when Asp936Glu (in exon 18) was included in the at-risk haplotype H4 for association analysis, the haplotypes H6 and H7, including a G or a T allele respectively, were no longer significantly associated with the disease (P corr Ͼ 0.05). Thus, Asp936Glu is less likely to be a risk factor for exudative AMD in Chinese individuals, indicating the C-terminal of the factor H contributes less than other parts of the polypeptide to the development of exudative AMD. This observation is consistent with the findings of Hageman et al

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts