Ultrafast all-optical wavelength conversion in silicon waveguides using femtosecond pump-probe pulses

Experimental results on ultrafast all-optical wavelength conversion in silicon-on-insulator waveguides are presented. Red and blue shifts of 10nm have been observed in femtosecond pump-probe experiments. Alloptical switching and the importance of waveguide dispersion are discussed

Quelques remarques concernant l'influence de la culture sur le développement du profil pédogénétique

The process of natural profile development, which is often to be brought to a standstill in cultivated soils, seems on the contrary to continue in a specific direction ( at least in many parts of Belgium). The effect of profile development in cultivated soils was studied in the Belgian polder area on sandy sediments, cultivated very soon after their deposition towards the VIIIth century. It seems impossible to classify these soils with one of the known Great Soil Groups of the temperate regions. It is thought that the described development in cultivated soils tends to change, although very slowly, the morphology of many of the Belgian gray brown podzolic soils on medium textured parent materials

Recurrent Plasmodium falciparum Malaria Infections in Kenyan Children Diminish T-Cell Immunity to Epstein Barr Virus Lytic but Not Latent Antigens

Plasmodium falciparum malaria (Pf-malaria) and Epstein Barr Virus (EBV) infections coexist in children at risk for endemic Burkitt's lymphoma (eBL); yet studies have only glimpsed the cumulative effect of Pf-malaria on EBV-specific immunity. Using pooled EBV lytic and latent CD8+ T-cell epitope-peptides, IFN-γ ELISPOT responses were surveyed three times among children (10 months to 15 years) in Kenya from 2002–2004. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated in association with Pf-malaria exposure, defined at the district-level (Kisumu: holoendemic; Nandi: hypoendemic) and the individual-level. We observed a 46% decrease in positive EBV lytic antigen IFN-γ responses among 5–9 year olds residing in Kisumu compared to Nandi (PR: 0.54; 95% CI: 0.30–0.99). Individual-level analysis in Kisumu revealed further impairment of EBV lytic antigen responses among 5–9 year olds consistently infected with Pf-malaria compared to those never infected. There were no observed district- or individual-level differences between Pf-malaria exposure and EBV latent antigen IFN-γ response. The gradual decrease of EBV lytic antigen but not latent antigen IFN-γ responses after primary infection suggests a specific loss in immunological control over the lytic cycle in children residing in malaria holoendemic areas, further refining our understanding of eBL etiology

An experimental investigation on mass transfer in presence of chemical reactions on a graphite cylinder in crossflow

In connection with analyses of hypothetical massive air ingress accidents in HTGR ($\underline{H}$igh $\underline{T}$emperature $\underline{G}$as-Cooled $\underline{R}$eactor), in which it is assumed that the air is transported through the hot region of graphite core support posts, experiments on mass transfer and in-pore diffusion with homogeneous and heterogeneous chemical reactions were performed on a graphite cylinder in crossflow. Two BLMR ($\underline{B}$oundary $\underline{L}$ayer $\underline{M}$ass transfer controlled $\underline{R}$egime) runs and two runs in an intermediate regime between BLMR and IPDR ($\underline{I}$n-$\underline{P}$ore-$\underline{D}$iffusion controlled $\underline{R}$egime) were executed at atmospheric pressures, Reynolds numbers ranging from 533 to 2490, and cylinder temperatures from 848°C to 1120°C. The nuclear grade graphite cylinder having a diameter of 100 mm and a porosity of 21.2 % was corroded in a nitrogen gas flow containing approximately 5 % oxygen. Mean and local mass transfer coefficients and corrosion rates were obtained to examine the influences of the chemical reactions on the mass transfer. As a result it can be concluded that the chemical reactions and small changes in shape do not significantly influence the mass transfer under conditions to be expected in HTGR air ingress accidents and that thus the analogy between heat and mass transfer can be used for safety calculations

Malaria enhances expression of CC chemokine receptor 5 on placental macrophages

Malaria and human immunodeficiency virus (HIV) coinfections are common in pregnant women in sub-Saharan Africa. The current study shows that placentas of malaria-infected women contain 3 times as much CC chemokine receptor 5 (CCR5) RNA as placentas of women without malaria. By immunohistochemistry, CCR5(+) maternal macrophages were seen in placentas from malaria-infected women but not in placentas from malaria-uninfected women. In addition, CCR5 also was found on fetal Hofbauer cells in placentas from both groups. Thus, malaria infections increase the potential reservoir for HIV in the placenta by increasing the number of HIV target cells

Malaria and pregnancy: placental cytokine expression and its relationship to intrauterine growth retardation

Malaria infections during pregnancy can lead to the delivery of low-birth-weight infants. In this study, cytokine mRNA was measured in placentas from 23 malaria-infected and 21 uninfected primigravid women who had delivered in Mangochi, Malawi, a region with a high rate of transmission of falciparum malaria. Significantly increased expression of interleukin (IL)-1beta, IL-8, and tumor necrosis factor (TNF)-alpha and decreased expression of IL-6 and transforming growth factor-beta1 were found in malaria-infected compared with uninfected placentas. TNF-alpha and IL-8 were produced by maternally derived hemozoin-laden placental macrophages. Increased TNF-alpha expression was associated with increased placental hemozoin concentrations. Increased TNF-alpha or IL-8 expression in the placenta was associated with intrauterine growth retardation but not with preterm delivery. The results suggest that malaria infections induce a potentially harmful proinflammatory response in the placenta

Microgeographic variations in Burkitt's lymphoma incidence correlate with differences in malnutrition, malaria and Epstein–Barr virus

BACKGROUND: Endemic Burkitt\u27s lymphoma (eBL) has been associated with Epstein-Barr virus (EBV) and holoendemic Plasmodium falciparum malaria. But recent evidence suggests that other risk factors are involved. METHODS: We hypothesised that selenoprotein glutathione peroxidase (GPx), a surrogate of nutritional status, is an important biomarker for eBL risk. We measured plasma GPx, anthropometric markers of malnutrition, EBV viral loads and malaria parasitaemia in children aged 1-9 years (n=258) from two locations in Nyanza Province, Kenya, with higher-than-expected and lower-than-expected incidence of eBL. The study participants were malaria asymptomatic children from the community. RESULTS: Children from eBL high-incidence areas had significantly lower GPx levels, high EBV viral load and more evidence of chronic malnutrition than children from eBL low-incidence areas (all P\u3c0.001). Additionally, GPx levels were significantly lower in children with the highest EBV viral load and for those with P. falciparum infections (P=0.035 and P=0.004, respectively). CONCLUSIONS: These results suggest that selenium deficiency may be a risk factor for eBL

Організаційно-економічні основи розвитку соціальної відповідальності промисловго підприємства

Сучасний етап розвитку суспільства характеризується суттєвими змінами в усіх сферах соціального та економічного життя. Довготривалий економічний спад після відновлення незалежності України обумовив зниження соціальної активності підприємств, а сучасні кризові тенденції негативно позначаються на виконанні соціальних функцій державою. Це, поряд з постійними трансформаційними процесами, призводить до зниження якості життя й негативно впливає на розвиток економіки. Впровадження принципів соціальної відповідальності в бізнес- процеси виступає чинником подальшого розвитку підприємства та набуває першочергового значення при вирішенні ряду соціальних проблем. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/1581

Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity

Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-gamma) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-gamma responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-gamma responses rarely correlated with each other; however, MSP1-specific IFN-gamma response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia

Mutations in the M-Gene Segment Can Substantially Increase Replication Efficiency of NS1 Deletion Influenza A Virus in MDCK Cells

Influenza viruses unable to express NS1 protein (delNS1) replicate poorly and induce high amounts of interferon (IFN). They are therefore considered as candidate viruses for live-attenuated influenza vaccines. Their attenuated replication is generally assumed to result from the inability to counter the antiviral host response, as delNS1 viruses replicate efficiently in Vero cells, which lack IFN expression. In this study, delNS1 virus was parallel passaged on IFN competent MDCK cells, which resulted in two strains that were able to replicate to high virus titres in MDCK cells due to adaptive mutations in especially the M-gene segment, but also the NP and NS gene segments. Most notable were clustered U-to-C mutations in the M segment of both strains and clustered A-to-G mutations in the NS segment of one strain, which presumably resulted from host cell mediated RNA editing. The M segment mutations in both strains changed the ratio of M1 to M2 expression, probably by affecting splicing efficiency. In one virus, 2 amino acid substitutions in M1 additionally enhanced virus replication, possibly through changes in the M1 distribution between the nucleus and the cytoplasm. Both adapted viruses induced equal levels of IFN as delNS1 virus. These results show that the increased replication of the adapted viruses is not primarily due to altered IFN induction, but rather related to changes in M1 expression or localization. The mutations identified in this paper may be used to enhance delNS1 virus replication for vaccine production