Analyzing Key Factors Influencing Water Transport in Open Air-Cooled PEM Fuel Cells.

The current limitations of air-cooled proton exchange membrane fuel cells (AC-PEMFCs) in water and heat management remain a major obstacle to their commercialization. A 90 cm full-size AC-PEMFC multi-physical field-coupled numerical model was constructed; isothermal and non-isothermal calculations were performed to explore the effects of univariate and multivariate variables on cell performance, respectively. The isothermal results indicate that lower temperature is beneficial to increase the humidity of MEA, and distribution uniformity at lower stoichiometric ratios and lower temperatures is better.

Continuous double-strand break induction and their differential processing sustain chiasma formation during Caenorhabditis elegans meiosis.

Faithful chromosome segregation into gametes depends on Spo11-induced DNA double-strand breaks (DSBs). These yield single-stranded 3' tails upon resection to promote crossovers (COs). While early Mre11-dependent end resection is the predominant pathway in most organisms, Exo1 or Dna2/BLM can also contribute to the efficient processing of meiotic DSBs.

Effect of mobile learning on academic achievement and attitude of Sudanese dental students: a preliminary study.

Background: Despite the great development of smart phone programs and applications, and the wide-spread of these devices among students, their use for the educational purposes remains weak. The study aimed to investigate to what extent utilizing mobile learning as an adjunct to classic classroom lectures affect students' academic achievement and, to assess their attitude toward using mobile application as an instructional method in dental education.

Methods: A quasi-experimental study was conducted among undergraduate dental students from two Sudanese universities.

Atypical purpura location in a Sudanese infant with Henoch-Schönlein purpura.

Henoch-Schönlein purpura (HSP) is a self-limited systemic vasculitis seen most commonly in paediatric group with multi organ involvements. We report a case of an infantile female who presented with cough, diarrhoea and vomiting. Two days later, she suddenly developed an erythematous, non-pruritic rash involving feet, thighs, buttocks and face; the lesion spared the trunk.