An Upgraded Transverse Electromagnetic Parallel Plates for Dielectric Measurement

A new version of transverse electromagnetic parallel plates with irregular plates’ width and plate separation has been developed for dielectric measurement. The separations between the plates are supported by four rectangular Teflon block and 1 mm of groove is proposed at the center of the upper plate to maintain the measurement repeatability. The groove enables the samples which are slightly higher than 2 cm to be fitted well between the plates without introducing extra force to the plates. Theperformance of both parallel plates has been compared in the frequency range from 100 MHz to 1.1 GHz. It is found that the upgraded parallel plate offers better return loss and insertion loss above 500 MHz compared to the previous parallel plate. It is reported from this work that the return loss of the parallel plate must be lower than -15 dB in order to achieve accurate dielectric constant. However, the insertion loss of the parallel plates does not influence the real permeability significantly. The upgraded TEM parallel plateproduces a consistent reading with a standard deviation of less than 0.05 above frequency 200 MHz. The dielectric measurement of Polypropylene (PP) has proven the capability of this upgraded TEM parallelplate

Signal Penetration towards Wooden Building Construction Materials

This paper emphasize on the effect of mobile signal penetration towards wooden building construction materials in Malaysia. The results of signal strength measurement at frequency 900MHz in the anechoic chamber with different types of wooden building construction materials and thickness is presented. The objectives of these experiments are to identify the types of wooden building materials in Malaysia that have significant impact into signal penetration and determine the effect of the identified wooden materials thickness towards signal penetration into building materials. This paper also report on the anechoic chamber and experiment setup that is used in the experimen

Gender disparities in pulmonary hypertension at a tertiary centre in Cameroon

Background. Pulmonary hypertension (PH) is a potent cause of heart failure and has been little investigated in the African setting. Objective. To investigate the effects of gender on the clinical presentation, echocardiographic features and outcomes of patients with PH in Douala, Cameroon. Methods. A prospective cohort study was conducted from March 2012 to December 2013 as part of the Pan African Pulmonary Hypertension Cohort study. PH was diagnosed by echocardiography and defined as a right ventricular systolic pressure >35 mmHg in the absence of acute right heart failure. Patients were followed up for a maximum of 12 months for primary endpoint mortality. Results. In total, 130 patients with PH were recruited; 71 (54.6%) were women. The median age was 59.2 years for men and 58.3 years for women (p=0.76). Active smoking and alcohol use were more frequent in men than women (both p<0.001), but women had greater exposure to indoor cooking fumes than men (p<0.001). Previous tuberculosis infection (11.3% v. 1.7%) and S3 gallop rhythm (30.9% v. 11.9%) were more common in women (both p<0.03). Women had a significantly higher mean systolic blood pressure (134 mmHg v. 125 mmHg; p=0.04) and pulse pressure (53.8 mmHg v. 44.9 mmHg; p=0.01) and a lower mean haemoglobin concentration (10.4 g/dL v. 12.4 g/dL; p<0.05) compared with men. Echocardiographic left ventricular (LV) systolic dysfunction was more frequent in men: mean LV ejection fraction 42.6% v. 51.5% (p=0.01) and mean fractional shortening 21.4% v. 28.6% (p=0.01). The overall mortality rate was 20.3%, and rates were similar in the two groups (Kaplan-Meier log rank 1.1; p=0.30). Conclusions. Despite differences in baseline characteristics including cardiovascular risk factors, mortality rates on follow-up were similar in men and women in this study. However, these different baseline characteristics probably suggest differences in the pathogenesis of PH in men and women in our setting that need further investigation.S Afr Med J 2017;107(10):892-89

Na+ and K+ transport and maturation stage ameloblast modulation

Introduction: Enamel mineralization requires calcium transport into the extracellular matrix for the synthesis of hydroxyapatite (HA) crystals. Formation of HA releases protons into the matrix, which are then neutralized when ameloblasts modulate from cells with apical invaginations, the so-called ruffle-ended ameloblasts (RE), to smooth-ended ameloblasts (SE). Ameloblast modulation is associated with the translocation of the calcium exchanger Nckx4 to the apical border of RE, to remove Na+ from the enamel matrix in exchange for Ca2+ and K+. As enamel matures, Na+ and K+ in the matrix progressively decrease. However, the transporter to remove K+ from mineralizing enamel has not been identified.Methods: Expression of K+ exchangers and channels in secretory and maturation stage of enamel organs were compared following an RNA-seq analysis. Kcnj15, which encodes the Kir4.2 inwardly rectifying K+ channel, was found to be the most upregulated internalizing K+ transporter in maturation stage of enamel organs. Kir4.2 was immunolocalized in wt, Nckx4−/−, Wdr72−/−, and fluorosed ameloblasts. Regulation of Wdr72 expression by pH was characterized in vitro and in vivo.Results: Kir4.2 immunolocalized to the apical border of wild type (wt) mouse RE and cytosol of SE, a spatial distribution pattern shared by NCKX4. In Nckx4−/− ameloblasts, Kir4.2 also localized to the apical surface of RE and cytosol of SE. However, in fluorosed and Wdr72−/− ameloblasts, in which vesicle trafficking is disrupted, Kir4.2 remained in the cytosol. In vitro, Wdr72 was upregulated in LS8 cells cultured in medium with a pH 6.2, which is the pH of the enamel matrix underlying RE, as compared to pH 7.2 under SE.Conclusion: Taken together these results suggest that Kir4.2 participates in K+ uptake by maturation ameloblasts, and that K+ and Na+ uptake by Kir4.2 and Nckx4, respectively, may be regulated by pH through WDR72-mediated endocytosis and membrane trafficking

Phenotypic Data from Inbred Parents Can Improve Genomic Prediction in Pearl Millet Hybrids

Pearl millet is a non-model grain and fodder crop adapted to extremely hot and dry environments globally. In India, a great deal of public and private sectors’ investment has focused on developing pearl millet single cross hybrids based on the cytoplasmic-genetic male sterility (CMS) system, while in Africa most pearl millet production relies on open pollinated varieties. Pearl millet lines were phenotyped for both the inbred parents and hybrids stage. Many breeding efforts focus on phenotypic selection of inbred parents to generate improved parental lines and hybrids. This study evaluated two genotyping techniques and four genomic selection schemes in pearl millet. Despite the fact that 6· more sequencing data were generated per sample for RAD-seq than for tGBS, tGBS yielded more than 2· as many informative SNPs (defined as those having MAF \u3e 0.05) than RAD-seq. A genomic prediction scheme utilizing only data from hybrids generated prediction accuracies (median) ranging from 0.73-0.74 (1000- grain weight), 0.87-0.89 (days to flowering time), 0.48-0.51 (grain yield) and 0.72-0.73 (plant height). For traits with little to no heterosis, hybrid only and hybrid/inbred prediction schemes performed almost equivalently. For traits with significant mid-parent heterosis, the direct inclusion of phenotypic data from inbred lines significantly (P \u3c 0.05) reduced prediction accuracy when all lines were analyzed together. However, when inbreds and hybrid trait values were both scored relative to the mean trait values for the respective populations, the inclusion of inbred phenotypic datasets moderately improved genomic predictions of the hybrid genomic estimated breeding values. Here we show that modern approaches to genotyping by sequencing can enable genomic selection in pearl millet. While historical pearl millet breeding records include a wealth of phenotypic data from inbred lines, we demonstrate that the naive incorporation of this data into a hybrid breeding program can reduce prediction accuracy, while controlling for the effects of heterosis per se allowed inbred genotype and trait data to improve the accuracy of genomic estimated breeding values for pearl millet hybrids

Methylation-associated silencing of miR-193a-3p promotes ovarian cancer aggressiveness by targeting GRB7 and MAPK/ERK pathways

Human growth factor receptor-bound protein-7 (GRB7) is a pivotal mediator involved in receptor tyrosine kinase signaling and governing diverse cellular processes. Aberrant upregulation of GRB7 is frequently associated with the progression of human cancers. However, the molecular mechanisms leading to the upregulation of GRB7 remain largely unknown. Here, we propose that the epigenetic modification of GRB7 at the post-transcriptional level may be a crucial factor leading to GRB7 upregulation in ovarian cancers. Methods: The upstream miRNA regulators were predicted by in silico analysis. Expression of GRB7 was examined by qPCR, immunoblotting and immunohistochemical analyses, while miR-193a-3p levels were evaluated by qPCR and in situ hybridization in ovarian cancer cell lines and clinical tissue arrays. MS-PCR and pyrosequencing analyses were used to assess the methylation status of miR-193a-3p. Stable overexpression or gene knockdown and Tet-on inducible approaches, in combination with in vitro and in vivo tumorigenic assays, were employed to investigate the functions of GRB7 and miR-193a-3p in ovarian cancer cells. Results: Both miR-193a-3p and its isoform, miR-193b-3p, directly targeted the 3' UTR of GRB7. However, only miR-193a-3p showed a significantly inverse correlation with GRB7-upregulated ovarian cancers. Epigenetic studies revealed that methylation-mediated silencing of miR-193a-3p led to a stepwise decrease in miR-193a-3p expression from low to high-grade ovarian cancers. Intriguingly, miR-193a-3p not only modulated GRB7 but also ERBB4, SOS2 and KRAS in the MAPK/ERK signaling pathway to enhance the oncogenic properties of ovarian cancer cells in vitro and in vivo. Conclusion: These findings suggest that epigenetic silencing of miR-193a-3p by DNA hypermethylation is a dynamic process in ovarian cancer progression, and miR-193a-3p may be explored as a promising miRNA replacement therapy in this disease.published_or_final_versio

The Impact of Chromate on Pseudomonas aeruginosa Molybdenum Homeostasis

Acquisition of the trace-element molybdenum via the high-affinity ATP-binding cassette permease ModABC is essential for Pseudomonas aeruginosa respiration in anaerobic and microaerophilic environments. This study determined the X-ray crystal structures of the molybdenum-recruiting solute-binding protein ModA from P. aeruginosa PAO1 in the metal-free state and bound to the group 6 metal oxyanions molybdate, tungstate, and chromate. Pseudomonas aeruginosa PAO1 ModA has a non-contiguous dual-hinged bilobal structure with a single metal-binding site positioned between the two domains. Metal binding results in a 22° relative rotation of the two lobes with the oxyanions coordinated by four residues, that contribute six hydrogen bonds, distinct from ModA orthologues that feature an additional oxyanion-binding residue. Analysis of 485 Pseudomonas ModA sequences revealed conservation of the metal-binding residues and β-sheet structural elements, highlighting their contribution to protein structure and function. Despite the capacity of ModA to bind chromate, deletion of modA did not affect P. aeruginosa PAO1 sensitivity to chromate toxicity nor impact cellular accumulation of chromate. Exposure to sub-inhibitory concentrations of chromate broadly perturbed P. aeruginosa metal homeostasis and, unexpectedly, was associated with an increase in ModA-mediated molybdenum uptake. Elemental analyses of the proteome from anaerobically grown P. aeruginosa revealed that, despite the increase in cellular molybdenum upon chromate exposure, distribution of the metal within the proteome was substantially perturbed. This suggested that molybdoprotein cofactor acquisition may be disrupted, consistent with the potent toxicity of chromate under anaerobic conditions. Collectively, these data reveal a complex relationship between chromate toxicity, molybdenum homeostasis and anaerobic respiration.Eve A. Maunders, Dalton H. Y. Ngu, Katherine Ganio, Sheikh I. Hossain, Bryan Y. J. Lim, Michael G. Leeming, Zhenyao Luo, Aimee Tan, Evelyne Deplazes, Boštjan Kobe, and Christopher A. McDevit

Gender disparities in pulmonary hypertension at a tertiary centre in Cameroon

Background. Pulmonary hypertension (PH) is a potent cause of heart failure and has been little investigated in the African setting.Objective. To investigate the effects of gender on the clinical presentation, echocardiographic features and outcomes of patients with PH in Douala, Cameroon.Methods. A prospective cohort study was conducted from March 2012 to December 2013 as part of the Pan African Pulmonary Hypertension Cohort study. PH was diagnosed by echocardiography and defined as a right ventricular systolic pressure >35 mmHg in the absence of acute right heart failure. Patients were followed up for a maximum of 12 months for primary endpoint mortality.Results. In total, 130 patients with PH were recruited; 71 (54.6%) were women. The median age was 59.2 years for men and 58.3 years for women (p=0.76). Active smoking and alcohol use were more frequent in men than women (both p<0.001), but women had greater exposure to indoor cooking fumes than men (p<0.001). Previous tuberculosis infection (11.3% v. 1.7%) and S3 gallop rhythm (30.9% v. 11.9%) were more common in women (both p<0.03). Women had a significantly higher mean systolic blood pressure (134 mmHg v. 125 mmHg; p=0.04) and pulse pressure (53.8 mmHg v. 44.9 mmHg; p=0.01) and a lower mean haemoglobin concentration (10.4 g/dL v. 12.4 g/dL; p<0.05) compared with men. Echocardiographic left ventricular (LV) systolic dysfunction was more frequent in men: mean LV ejection fraction 42.6% v. 51.5% (p=0.01) and mean fractional shortening 21.4% v. 28.6% (p=0.01). The overall mortality rate was 20.3%, and rates were similar in the two groups (Kaplan-Meier log rank 1.1; p=0.30).Conclusions. Despite differences in baseline characteristics including cardiovascular risk factors, mortality rates on follow-up were similar in men and women in this study. However, these different baseline characteristics probably suggest differences in the pathogenesis of PH in men and women in our setting that need further investigation.

International Study of the Epidemiology of Paediatric Trauma : PAPSA Research Study

Objectives: Trauma is a significant cause of morbidity and mortality worldwide. The literature on paediatric trauma epidemiology in low- and middle-income countries (LMICs) is limited. This study aims to gather epidemiological data on paediatric trauma. Methods: This is a multicentre prospective cohort study of paediatric trauma admissions, over 1 month, from 15 paediatric surgery centres in 11 countries. Epidemiology, mechanism of injury, injuries sustained, management, morbidity and mortality data were recorded. Statistical analysis compared LMICs and high-income countries (HICs). Results: There were 1377 paediatric trauma admissions over 31 days; 1295 admissions across ten LMIC centres and 84 admissions across five HIC centres. Median number of admissions per centre was 15 in HICs and 43 in LMICs. Mean age was 7 years, and 62% were boys. Common mechanisms included road traffic accidents (41%), falls (41%) and interpersonal violence (11%). Frequent injuries were lacerations, fractures, head injuries and burns. Intra-abdominal and intra-thoracic injuries accounted for 3 and 2% of injuries. The mechanisms and injuries sustained differed significantly between HICs and LMICs. Median length of stay was 1 day and 19% required an operative intervention; this did not differ significantly between HICs and LMICs. No mortality and morbidity was reported from HICs. In LMICs, in-hospital morbidity was 4.0% and mortality was 0.8%. Conclusion: The spectrum of paediatric trauma varies significantly, with different injury mechanisms and patterns in LMICs. Healthcare structure, access to paediatric surgery and trauma prevention strategies may account for these differences. Trauma registries are needed in LMICs for future research and to inform local policy