Effect of energy relaxation on injected current pulse in high-frequency IMPATT diodes

The effect of energy relaxation on carrier injection in millimetre-wave IMPATT diodes is considered. For this purpose, an approximate formula relating the current pulse injected in the transit region, including the energy relaxation, is derived. Its influence on the RF impedance of the impatt oscillator is discussed.     

One-dimensional extended lines of divacancy defects in graphene

Since the outstanding transport properties of graphene originate from its specific structure, modification at the atomic level of the graphene lattice is needed in order to change its electronic properties. Thus, topological defects play an important role in graphene and related structures. In this work, one-dimensional (1D) arrangement of topological defects in graphene are investigated within a density functional theory framework. These 1D extended lines of pentagons, heptagons and octagons are found to arise either from the reconstruction of divacancies, or from the epitaxial growth of graphene. The energetic stability and the electronic structure of different ideal extended lines of defects are calculated using a first-principles approach. Ab initio scanning tunneling microscopy (STM) images are predicted and compared to recent experiments on epitaxial graphene. Finally, local density of states and quantum transport calculations reveal that these extended lines of defects behave as quasi-1D metallic wires, suggesting their possible role as reactive tracks to anchor molecules or atoms for chemical or sensing applications.     

Assessment of dietary exposure to annatto (E160b), nitrites (E249-250), sulphites (E220-228) and tartaric acid (E334) in the French population: the second French total diet study

The results of the assessment of the dietary exposure to annatto, nitrites, tartaric acid and sulphites within the framework of the second French total diet study (TDS) are reported. These 4 additives were selected from the Bemrah et al. study [Bemrah N, Leblanc JC, Volatier JL. 2008. Assessment of dietary exposure in the French population to 13 selected food colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners. Food Addit Contam B. 1(1):2-14] on 13 food additives which identified a possible health risk for annatto, sulphites and nitrites and a lack of data for tartaric acid. Among the composite samples selected for the whole TDS, 524 were analysed for additives (a sample was analysed for a given additive when it was identified as a major contributor for this additive only): 130 for tartaric acid, 135 for nitrites, 59 for annatto and 200 for sulphites. Estimated concentrations (minimum lower bound to maximum upper bound) vary nationally from 0 to 9 mg/kg for annatto, 0 to 420 mg/kg for tartaric acid, 0 to 108 mg/kg for sulphites and 0 to 3.4 mg/kg for nitrites. Based on the analytical results, the dietary exposure was calculated for adults and children, separately, using lower bound and upper bound assumptions. The European ADIs for these 4 additives were not exceeded except for the dietary exposure for sulphites among 2.9% of the adult population, where the major contributors were alcoholic drinks and especially wine under both hypotheses (lower and upper bound).     

Modulation of placental protein expression of OLR1: implication in pregnancy-related disorders or pathologies

The lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (OLR1) is a newly described receptor for oxidatively modified LDL. The human pregnancy is associated with hyperlipidemia and oxidative stress. It has been reported that modification in maternal lipid profile can induce disturbance during pregnancy. In this study, we have evaluated the expression protein level of OLR1 in human term placenta of women having plasma cholesterol level lower to 7 mM or higher to 8 mM and women of gestational diabetes mellitus (GDM) by western blot analysis. The present study demonstrates that the maternal lipid profile is associated with placental protein expression of OLR1. A significant increase in the protein expression of OLR1 was observed in placenta of women with elevated plasmatic total cholesterol level (>8 mM). In addition, the placental protein expression of OLR1 is increased in mothers having the highest pre-pregnancy body mass index (BMI) and low (<7 mM) plasmatic total cholesterol level at term. Interestingly, the placental protein expression of OLR1 is increased in the presence of GDM pregnancies compared with normal lipids level pregnancies, without the modification of mRNA expression. In conclusion, placental OLR1 protein expression is associated with maternal lipid profile, pre-pregnancy BMI, and pathology of GDM.     

Associations between tumor necrosis factor-alpha and lymphotoxin-alpha polymorphisms and idiopathic recurrent miscarriage

Heightened expression of tumor necrosis factor (TNF)-alpha and lymphotoxin-alpha (LT-alpha) was associated with pregnancy complications, including idiopathic recurrent miscarriage (RM). Whereas TNF-alpha and LT-alpha gene polymorphisms affect serum cytokine concentrations, their contribution to RM is controversial. The single nucleotide polymorphisms (SNPs) TNF-alpha (-238G/A, -308G/A) and LT-alpha (+252A/G) were investigated in 350 RM women and 200 control women. Higher frequency of the TNF-alpha -238A, but not the TNF-alpha -308A or the LT-alpha+252G, allele was seen in patients, with comparable frequencies of TNF-alpha -238G/A, TNF-alpha -308G/A, and LT-alpha+252A/G genotypes seen between both groups, except for TNF-alpha -238G/G, which was lower in patients. Regression analysis confirmed the association of the TNF-alpha -238G/A SNP with idiopathic RM, and both TNF-alpha -308A/TNF -238G/LT-alpha+252G and TNF-alpha -308G/TNF-alpha -238A/LT-alpha+252G haplotypes played a susceptible role in idiopathic RM. TNF-alpha -238G/A and -238A/A, and LT-alpha+252G/G genotypes were positively associated only with exclusively early RM. This supports the concept of the association of TNF-alpha (-238G/A) and LT-alpha (+252A/G) polymorphic variants in idiopathic RM.     

泥炭的物理特性:基质的关键因子

本研究定义了影响植物根系利用泥炭基质中空气和水分的物理性质指标(持水性、可湿性、稳定性),这些指标广泛用于评估基质原材料性质。泥炭物理性质分析结果证明,弱分解(H1~H5)的藓类泥炭是基质生产不可缺少的,尽管泥炭替代材料可以提高基质通透性能,但尚未有任何材料能够达到泥炭所具有的优良性状。     

Evaluation of Nine Semi-pilot Scale Whey Pretreatment Modifications for Producing Whey Protein Concentrate

Cheese whey was chemically pretreated and subjected to one of nine semi-pilot scale, physical pretreatment modifications involving various combinations of centrifugal clarification (CC) and/or microfiltration (MF) to remove residual lipids and phospholipoprotein complexes. Two pretreatment modifications were most effective for producing whey with least turbidity and lowest lipid and phospholipid contents. Whey given these two pretreatments provided highest ultrfiltration (UF) membrane flux rate and upon drying of the UF retentate resulted in the most highly functional WPCs in terms of solubility, foam expansion, emulsifying activity and gelation.     

A taper filtering finline at millimeter wavelengths for broadband harmonic multiplication

The design of a taper filtering finline aimed at simultaneously mode matching and frequency selecting multifrequency signal is presented. Based on the superimposition of a smoothly corrugated taper and a sinusoidal-shaped filter, a low insertion loss (L<0.1 dB) at W band [75:110] GHz and a high rejected stop band in the third harmonic range (R band [225:330] GHz) are demonstrated. Both sections are numerically optimized using chain matrix techniques and assessed by means of full three-dimensional electromagnetic simulations.     

A highly directive dipole antenna embedded in a Fabry-Perot typecavity

We investigate the origin of the directivity of a dipole antenna embedded in a dielectric slab Fabry-Perot cavity. It is shown that the focusing effect is due to the angular selection rules in the Bragg-type mirror and is directly correlated to the frequency selectivity of the cavity. For a 6 GHz resonant device, having a quality factor of 100, the aperture of the beam pattern (E-H plane) is close to 12° in agreement with the arguments based on frequency and angular selectivities. Hence, this kind of cavity could be used in free-space based communication links     

PHIDEO: High-level synthesis for high throughput applications

This paper describes a new approach to high-level synthesis for high throughput applications. Such applications are typically found in real-time video systems such as HDTV. The method is capable of dealing with hierarchical flow graphs containing loops with manifest boundaries and linear index expressions. The algorithm is based on the model of periodic operations which allows optimizations across loop boundaries. Processing units and storage units are minimized simultaneously. The algorithm is implemented in thePHIDEO system. The major parts of this system are the processing unit synthesis, the scheduler and the memory synthesis including address generation.