On Maps of Period 2 on Prime and Semiprime Rings

A map f of the ring R into itself is of period 2 if f2x=x for all x∈R; involutions are much studied examples. We present some commutativity results for semiprime and prime rings with involution, and we study the existence of derivations and generalized derivations of period 2 on prime and semiprime rings

Absorbing photonic crystals for thin film photovoltaics

The absorption of thin hydrogenated amorphous silicon layers can be efficiently enhanced through a controlled periodic patterning. Light is trapped through coupling with photonic Bloch modes of the periodic structures, which act as an absorbing planar photonic crystal. We theoretically demonstrate this absorption enhancement through one or two dimensional patterning, and show the experimental feasibility through large area holographic patterning. Numerical simulations show over 50% absorption enhancement over the part of the solar spectrum comprised between 380 and 750nm. It is experimentally confirmed by optical measurements performed on planar photonic crystals fabricated by laser holography and reactive ion etching.Comment: 6 pages. SPIE Photonics Europe pape

ORFV virus manipulation of type I interferon expression

Orf virus (ORFV) is the type species of the Parapoxvirus genus that belongs to the Poxviridae family. ORFV is an epitheliotropic virus inducing cutaneous pustular skin lesions in sheep and goats and is transmissible to humans. Type I interferons (IFN) are critical in the host defence against viruses. They induce hundreds of interferon stimulated genes (ISGs) many of which have an antiviral role. The aim of this study was to investigate whether ORFV modulates the type I IFN response. Previous studies suggested a role for the ORFV gene ORF116 in modulating the ISG response using a recombinant ORF116 deletion mutant. These preliminary findings were validated in this study by constructing an ORF116 revertant recombinant virus. The approach taken was to generate a revertant virus in which the ORF116 gene was re-inserted at the same locus as the deleted ORF116 gene in the knockout virus by homologous recombination and then infecting HeLa cells with the two recombinant viruses and the wt strain and studying specific changes in ISG expression by qRT-PCR. The data suggested that ORFV was either directly modulating the expression of about 10 ISGs involved in the anti-viral response or indirectly modulating ISG expression by inhibiting IFN production or both. The ability of ORFV to modulate type I IFN production in several cell types was undertaken to investigate whether ORFV could inhibit IFN-β via dsRNA and dsDNA dependant signalling pathways. HEK293 cells were utilized to model an RNA sensing system. It has been shown that these cells respond to poly(dA:dT), that is converted to dsRNA via RNA polymerase III and poly(I:C) and produce high fold IFN-β expression of RIG-I-dependent signalling as confirmed by siRNA knock-down of RIG-I and RNA polymerase III. HEK293 cells are permissive for ORFV replication and ORFV caused a potent inhibition of IFN-β mRNA when stimulated with poly(dA:dT) or poly(I:C) in a dose-dependent manner. THP-1 cells and human dermal fibroblasts (hNDF) were used to investigate the effects of ORFV on a cytoplasmic DNA sensing system. These cells respond to transfected poly(dA:dT) or poly(I:C) by producing high levels of IFN-β expression in a dose-dependent manner. Both cells are permissive for ORFV early gene synthesis and only hNDFs are permissive for ORFV replication. ORFV infection resulted in strong inhibition of IFN-β in hNDFs treated with either poly(I:C) or poly(dA:dT). The IFN signalling pathway in hNDFs was characterized by RNA interference. siRNA knock-down of STING, a critical adaptor for cytosolic DNA sensing, resulted in a reduction in IFN-β expression in cells stimulated with poly(dA:dT) and this inhibition was further enhanced when both STING and RIG-I were knocked down. Although it was clearly shown that IFN induction was via DNA sensing, cytosolic DNA sensing has yet to be confirmed. Preliminary findings suggest that the two early genes ORF116 and ORF020 expressed from plasmid vectors are potentially involved in antagonising IFN expression. Overall, this study has shown for first time the ability of ORFV to counteract type I IFN expression by antagonising dsRNA and dsDNA activated IFN signalling pathways. This study suggests that ORFV early genes are involved in ISG modulation and IFN-β inhibition

Nutritional status of sub-Saharans residing in the city of El Jadida - Morocco: weight in relation to socio-economic status

Background. Onset of overweight and obesity has been previously reported as a result of population migration to western countries. Objective. To determine the nutritional status, weight status and their association with socioeconomic status in sub- Saharan settled in El Jadida city in a Mediterranean country Morocco. Materials and methods. A descriptive study was carried out in 2018 on 256 sub-Saharans migrants living in the city of El Jadida in Morocco. Information on socio-economic and socio-demographic characteristics as well as anthropometric measurements was collected. The body mass index (BMI) and abdominal obesity by measuring waist circumference (WC) and waist circumference to hip ratio (WHR) and the distribution of body fat by calculating the sum of skin folds are determined. Results. Analysis results indicate that height, waist circumference, hip circumference, sum of trunk skinfolds, total sum of skinfolds, and BMI increase with age. The prevalence of underweight decreases with age, overweight was 38.7% in the youngest age group (18-25 years) and reached higher values after 35 years (44.10%). In addition, the prevalence of general obesity (based on BMI) increased with age and abdominal obesity (based on WHR and WC) was more marked in sub-Saharan people aged 26 to 35 years. These results also reveal the coexistence of underweight, overweight and obesity in all age groups. The analysis revealed a significant association between several variables and obesity. Significant associations were found between age and BMI (P=0.04), between level of education (university) and WHR (p=0.02), between sex and WHR, and between sex and WC (p=0.049). The study revealed also that the majority of the study sample gained weight after their settling in the host country. Conclusions. The study data show that obesity including overweight and abdominal obesity were prevalent among sub- Saharan migrants residing in the city of El Jadida. This prevalence is associated with socio-demographic and socio- economic factors