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Genomic and genetic variation among six Italian chicken native breeds (Livornese, Mericanel della Brianza, Milanino, Bionda Piemontese, Bianca di Saluzzo and Siciliana) were studied using single nucleotide polymorphism (SNP) and copy number variants (CNV) as markers. A total of 94 DNA samples genotyped with Axiom® Genome-Wide Chicken Genotyping Array (Affymetrix) were used in the analyses. The results showed the genetic and genomic variability occurring among the six Italian chicken breeds. The genetic relationship among animals was established with a principal component analysis. The genetic diversity within breeds was calculated using heterozygosity values (expected and observed) and with Wright’s F-statistics. The individual-based CNV calling, based on log R ratio and B-allele frequency values, was done by the Hidden–Markov Model (HMM) of PennCNV software on autosomes. A hierarchical agglomerative clustering was applied in each population according to the absence or presence of definite CNV regions (CNV were grouped by overlapping of at least 1 bp). The CNV map was built on a total of 1003 CNV found in individual samples, after grouping by overlaps, resulting in 564 unique CNV regions (344 gains, 213 losses and 7 complex), for a total of 9.43 Mb of sequence and 1.03% of the chicken assembly autosome. All the approaches using SNP data showed that the Siciliana breed clearly differentiate from other populations, the Livornese breed separates into two distinct groups according to the feather colour (i.e. white and black) and the Bionda Piemontese and Bianca di Saluzzo breeds are closely related. The genetic variability found using SNP is comparable with that found by other authors in the same breeds using microsatellite markers. The CNV markers analysis clearly confirmed the SNP results.
Serum samples collected during the National Health and Nutrition survey (ENSANUT 2006) were obtained from subjects aged 1–95 years (January–October 2010) and analysed to assess the seroprevalence of Bordetella pertussis (BP) in Mexico. Subjects' gender, age, geographical region and socioeconomic status were extracted from the survey and compiled into a subset database. A total of 3344 subjects (median age 29 years, range 1–95 years) were included in the analysis. Overall, BP seroprevalence was 47·4%. BP seroprevalence was significantly higher in males (53·4%, P = 0·0007) and highest in children (59·3%) decreasing with advancing age (P = 0·0008). BP seroprevalence was not significantly different between regions (P = 0·1918) and between subjects of socioeconomic status (P = 0·0808). Women, adolescents and young adults were identified as potential sources of infection to infants. Booster vaccination for adolescents and primary contacts (including mothers) for newborns and infants may provide an important public health intervention to reduce the disease burden.
Recently, bimetallic nanostructures and nanoalloys have received special interest due to their promising chemical and physical properties. Specifically, Cu-Ni nanoparticles have been investigated for biomedical and catalytic applications. This work reports the synthesis of alloys and bimetallic nanoparticles of CuxNi100-x (x = 20, 40, 50, 60 and 80) by sol-gel method, and their morphological, structural and magnetic characterization. A precursor material was prepared using a standard Pechini method and then CuNi nanoparticles were obtained by calcination treatments of the precursor in H2/N2atmosphere at 600 and 700°C for 15 minutes. The resulting nanoparticles were characterized by X-ray diffraction (XRD), which reveals that this method led to the formation of CuNi substitutional nanoalloys and bimetallic nanoparticles with good cristallinity related with the calcination temperatures and Cu:Ni weight ratios. Transmission electron microscopy (TEM) shows nearly monodisperse and uniform spherical nanoparticles with sizes between 40 and 70 nm. The magnetic properties were studied using SQUID magnetometry, according with these results, the CuNi nanoparticles showed a ferromagnetic behavior, the magnetization value increases as a function of the weight percentage of Ni.
We report the synthesis, characterization, and implementation of various naphtho[2,3- b:6,7-b’]dithiophene (NDT)-based donor molecules for organic photovoltaics (OPVs) When NDT(TDPP)2 (TDPP = thiophene-capped diketopyrrolopyrrole) contains all branched 2- ethylhexyl chains and is combined with the electron acceptor PC61BM, a power conversion efficiency (PCE) of 4.06±0.6% is achieved. This respectable PCE is attributed to the broad, high oscillator strength visible absorption, the ordered molecular packing, and a high hole mobility of 0.04 cm2·V-1·s-1. We find utilizing linear C-12 side chains on either the TDPP or NDT framework dramatically increases the d-spacing, which directly correlates with inferior OPV device performance. This leads to the conclusion that the selection of an appropriate side chain plays a key role in determining OPV device performance of a small molecule donor.
To investigate the relationship between dietary patterns and self-perceived body shape silhouette and BMI in a sample of Mexican women.
A cross-sectional analysis of dietary habits from baseline data of a large cohort study (EsMaestra) conducted in 2006–2008.
The state of Veracruz, Mexico.
Mexican teachers (n 20 330) provided information on body shape silhouette at baseline, changes in body shape silhouette and BMI, as well as information on sociodemographic variables and lifestyle.
The median BMI was 26·8 kg/m2; 43 % of women were overweight and 24 % were obese. The carbohydrates, sweet drinks and refined foods pattern was associated with a greater risk of having a large silhouette and a large BMI (BMI ≥ 30·0 kg/m2v. BMI < 25·0 kg/m2; ORT1−3 = 1·86, 95 % CI 1·56, 2·22 and 1·47, 95 % CI 1·28, 1·69, respectively) with a significant trend when comparing the first and third tertiles of intake. The fruit and vegetable pattern was associated with a lower risk of having a large silhouette and a large BMI (ORT1−3 = 0·68, 95 % CI 0·57, 0·82 and ORT1−3 = 0·77, 95 % CI 0·67, 0·88, respectively) with a significant decreasing trend. Similar results were observed when change in silhouette (from 18 years of age to current silhouette) was considered.
High intakes of carbohydrates, sweet drinks and refined foods are related to larger silhouettes. Public health intervention improving access to healthy dietary guidelines, healthy food choice in the work place, promotion of physical activity and regulation of beverages with a high sugar content and of refined foods should be considered.
While it is clear that self-reported racial/ethnic discrimination is related to illness, there are challenges in measuring self-reported discrimination or unfair treatment. In the present study, we evaluate the psychometric properties of a self-reported instrument across racial/ethnic groups in a population-based sample, and we test and interpret findings from applying two different widely-used approaches to asking about discrimination and unfair treatment. Even though we found that the subset of items we tested tap into a single underlying concept, we also found that different groups are more likely to report on different aspects of discrimination. Whether race is mentioned in the survey question affects both frequency and mean scores of reports of racial/ethnic discrimination. Our findings suggest caution to researchers when comparing studies that have used different approaches to measure racial/ethnic discrimination and allow us to suggest practical empirical guidelines for measuring and analyzing racial/ethnic discrimination. No less important, we have developed a self-reported measure of recent racial/ethnic discrimination that functions well in a range of different racial/ethnic groups and makes it possible to compare how racial/ethnic discrimination is associated with health disparities among multiple racial/ethnic groups.
In this paper present experimental results on the quality of AIGaAs material after high concentrations of impurities have been introduced for the purpose of impurity induced disordering. A comparison between Zn and Si diffusion is presented, and the nature of the transition region between uniform alloy and as-grown periodic structure has been characterized both experimentally and theoretically. Device implications of these observations is discussed.
The effectiveness of CVD thin film backside gettering on n-type CZ silicon wafers for CMOS technology has been investigated using optical techniques for bulk microdefect analyses and transmission electron microscopy for interfacial structure study. The deposition of LPCVD polysilicon (500-2000 nm), silicon nitride (150 nm), or poly/nitride films on the backside of Si wafers was found to enhance the bulk precipitation. Bulk microdefect density increased as the thickness of polysilicon increased. At the polysilicon/silicon interface, no extended line defects from polysilicon were observed. Based on the results of minority carrier lifetime and oxide breakdown measurements, the best gettering efficiency was given by 1300 nm polysilicon backside gettering scheme.
The gettering effectiveness of various thin film structures on n-type CZ silicon wafers has been investigated using electron microscopy, synchrotron radiation topography and optical techniques. Polysilicon, silicon nitride, and poly/nitride films were deposited on etched wafer backsurfaces. The various materials characteristics were correlated with gate oxide breakdown voltage, minority carrier lifetime and yield of MOS capacitors. These studies show that the poly/nitride configuration is superior as a gettering technique.
The initial stages of heteroepitaxial growth of GaAs on Si have been observed using a technique of graded-thickness sample deposition. We find that an initial uniform passivating layer is grown, followed by three-dimensional nucleation determined by Ga diffusion and clustering, followed in turn by an interfacial reaction limited island growth mechanism. Results for various substrate temperatures and substrate orientations are consistent with the simple models of nucleation and growth.
The structural, compositional and electronic properties of the a-Si:H/a-SiNx:H interface are reported. High resolution TEM and light/dark ESR studies conclude that the interface has a finite width of the order of 10 Å. In addition, there is a high density of charges residing near the interface. Band bendings occur in both a-Si:H and a-SiNx:H, resulting in few neutral dangling bonds in the a-Si:H/a-SiNx:H multilayer structure. The depletion width in the nitride is of the order of 100 Å. The slow decay of the LESR in multilayers with thin sublayers is attributed to charges trapped in the slow states in the nitride.
Zinc selenide films have been grown heteroepitaxially on Si(100) substrates by molecular beam epitaxy. The growth has been carried out for raised substrate temperatures and also at room temperature followed by solid-phase epitaxial (SPE) regrowth. The ZnSe films have been characterized by a number of surface-sensitive techniques and both the interface and the bulk material have been examined with high resolution transmission electron microscopy (HRTEM). We find that an interlayer, which is most likely SiSex, is present between the ZnSe film and the Si substrate for growths made at 300 °C and causes loss of epitaxy. In the case of room temperature deposition and SPE, it is absent, leading to good epitaxy. In the latter situation, the films are very uniform and there is a 4° rotation of the ZnSe crystal axes relative to those of the Si substrate.
Metal-insulator-semiconductor capacitors are fabricated from a YBa2Cu3O7-δ (YBCOVYttria-Stabilized Zirconia(YSZ)/Si structure. Current-voltage(I-V) measurements reveal that thicker YBCO films(≤150Å) tend to result in more stable capacitors. Results of capacitance-voltage(C-V) measurements during bias-temperature cycling suggest the presence of a thermally activated process in the YSZ and/or YSZ/Si interface. This process is probably related to trapping/detrapping mechanisms in the SiOx, layer formed between YSZ and Si. It is shown that the distribution of mobile ions in YSZ can be “set” with biases at room temperature and then “frozen” by lowering the temperature, giving rise to adjustable threshold voltages at 80K.
The transition from amorphous to crystalline silicon in films prepared in a hydrogen-diluted silane plasma has been studied. Emphasis was placed on the role played by hydrogen during film growth. Hydrogen is found to govern the film formation process by promoting the reverse process, ‘etching’. By preferentially eliminating energetically unfavorable configurations during the film growth, hydrogen controls the atomic structure, hydrogen incorporation, and grain growth of the film. It affects the total hydrogen content in the film, as well as the way hydrogen is bonded to the silicon. Excessive hydrogen dilution, however, reduces the grain size by changing the columnar grain growth to a more spherical-like grain growth, and eventually eliminates film growth. With appropriate hydrogen dilution, plasma deposition was found to yield ‘polycrystalline’ silicon films which has a large distribution of grain sizes, with the largest grains being about 2000 Å.
The initial nucleation processes for reactions of Pd and Ti on Si are studied by Raman scattering, and Auger electron spectroscopy. The epitaxial nature of the structures is verified by high resolution TEM. A model of the interface reaction is presented which describes the initial interdiffusion and subsequent nucleation. The aspects of nucleation in a thin film reaction are compared to nucleation processes in vacuum deposition. For Pd/Si a critical depostion thickness is observed which is related to a critical nuclei size. For Ti/Si higher annealing temperatures are required to bring about conditions for nucleation of the suicide.
In this paper we introduce the technique of graded thickness sample deposition to study the heteroepitaxial growth mechanisms of GaAs on Si. We can observe the continuous evolution from the initial clean surface, through nucleation, growth and coalescence of the deposited material.
The results of a transmission electron microscopy (TEM) study of excimer laser crystallized a-Si:H thin films are described in this paper. High resolution TEM has shown the crystallization threshold of 10−2 P a-Si:H, grown by PECVD, to be 85 mj/cm2. TEM reveals that PECVD a-Si:H films crystallize in a stratified structure at laser energy densities greater than 120 mj/cm2. This stratified structure consists of a polycrystalline Si region near the surface, a microcrystalline region below the polycrystalline region and uncrystallized a-Si near the substrate. The depth of the crystallized region increases as the laser energy density increases. Spherical voids are also present in the film in the microcrystalline region. These voids are formed by H2 evolving from the film during crystallization. TEM also reveals that thermal annealing a 50 nm film of a-Si:H followed by laser crystallization produces 100 nm Si grains with low defect density.