Influence of laser preconditioning on the capacity of optical films to resist laser-induced damage

As a technique to improve the ability of optical films to resist laser-induced damage (ARLID), laser preconditioning has been investigated broadly. In this paper, the laser preconditioning effect has been analyzed based on the defect-initialized damage mechanism that the author had put forward previously. Theoretical results show that an energy density scope (PEDS) exists in which the preconditioning laser can effectively improve the ARLID of optical films. In addition, when the energy density of the testing laser pulse is altered, the boundary of PEDS will change accordingly. Experimental results have verified these theoretical assumptions. PEDS will also become wider if the critical energy density of the preconditioning laser that can induce films' micro-damage increases, or the critical energy density of the preconditioning laser that can cause laser annealing decreases. In these cases, it is relatively easy to improve the ARLID of optical films. Results of the current work show great significance in enhancing the ARLID of optical films through the laser preconditioning technique. (C) 2008 Elsevier B.V. All rights reserved.

Investigation of annealing effects on the laser-induced damage threshold of amorphous Ta2O5 films

Ta2O5 films were deposited using the conventional electron beam evaporation method and then annealed at temperatures in the range 373-673 K. Chemical composition, scattering and absorption were examined by X-ray photoelectron spectroscopy (XPS), total integrated scattering (TIS) measurement and the surface thermal lensing (m) technique, respectively. The laser-induced damage threshold (LIDT) was assessed using the output from an Nd:YAG laser with a pulse length of 12 ns. The results showed that the improvement of the LIDT after annealing was due to the reduced substoichiometric and structural defects present in the film. The LIDT increased slightly below 573K and then increased significantly with increase in annealing temperature, which could be attributed to different dominant defects. Moreover, the root mean square (RMS) roughness and scattering had little effect on the LIDT, while the absorption and the LIDT were in accord with a general relation. (c) 2008 Elsevier Ltd. All rights reserved.

Surface plasmon resonance transmission filters at 1053 nm based on metallic grating with narrow slit

Metallic gratings with narrow slits can lead to special optical properties such as strongly enhancing the transmission and considerably strengthening the polarized effect. A narrow-band filter suitable for application in optical communication is designed by sandwiching a metallic grating between two identical dielectric films. The maximum transmission can reach 96% after optimizing the parameters of films and grating at a central wavelength of 1053 nm. It is the first time, to our knowledge, that such high transmission has been reported since the discovery of the extraordinarily high transmission through periodic holes or slits; moreover, the extremely polarized effect is also found in P mode of this symmetric grating.

Influence of substoichiometer on the laser-induced damage characters of HfO2 thin films

HfO2 is one of the most important high refractive index materials for depositing high power optical mirrors. In this research, HfO2 thin films were prepared by dual-ion beam reactive sputtering method, and the laser-induced damage thresholds (LIDT) of the sample were measured in 1-on-1 mode for laser with 1064 nm wavelength. The results indicate that the LIDT of the as-grown sample is only 3.96 J/cm(2), but it is increased to 8.98 J/cm(2) after annealing under temperature of 200 degrees C in atmosphere. By measuring the laser weak absorption and SIMS of the samples, we deduced that substoichiometer is the main reason for the low LIDT of the as-grown sample, and the experiment results were well explained with the theory of electronic-avalanche ionization. (C) 2008 Elsevier B.V. All rights reserved.

Association of haplotypes spanning PDZ-GEF2, LOC728637 and ACSL6 with schizophrenia in Han Chinese

Background: Schizophrenia is a complex genetic disorder caused by multiple genetic and environmental factors. Several lines of linkage and association studies have repeatedly suggested that the chromosome 5q22-33 region is implicated in the aetiology of s

Rapid evolution of mammalian X-linked testis microRNAs

Background: MicroRNAs (miRNAs), which are small, non-coding RNAs approximately 21-nucleotides in length, have become a major focus of research in molecular biology. Mammalian miRNAs are proposed to regulate approximately 30% of all protein-coding genes. P

Diversity and evolution of MicroRNA gene clusters

microRNA (miRNA) gene clusters are a group of miRNA genes clustered within a proximal distance on a chromosome. Although a large number of miRNA clusters have been uncovered in animal and plant genomes, the functional consequences of this arrangement are

Small but influential: the role of microRNAs on gene regulatory network and 3 ' UTR evolution

MicroRNAs (miRNAs) are endogenous similar to 22 nucleotide noncoding RNAs that regulate the expression of complementary messenger RNAs (mRNAs). Thousands of miRNA genes have been found in diverse species, and many of them are highly conserved. With the mi

Characterization and Comparison of the Tissue-Related Modules in Human and Mouse

Background: Due to the advances of high throughput technology and data-collection approaches, we are now in an unprecedented position to understand the evolution of organisms. Great efforts have characterized many individual genes responsible for the interspecies divergence, yet little is known about the genome-wide divergence at a higher level. Modules, serving as the building blocks and operational units of biological systems, provide more information than individual genes. Hence, the comparative analysis between species at the module level would shed more light on the mechanisms underlying the evolution of organisms than the traditional comparative genomics approaches. Results: We systematically identified the tissue-related modules using the iterative signature algorithm (ISA), and we detected 52 and 65 modules in the human and mouse genomes, respectively. The gene expression patterns indicate that all of these predicted modules have a high possibility of serving as real biological modules. In addition, we defined a novel quantity, "total constraint intensity,'' a proxy of multiple constraints (of co-regulated genes and tissues where the co-regulation occurs) on the evolution of genes in module context. We demonstrate that the evolutionary rate of a gene is negatively correlated with its total constraint intensity. Furthermore, there are modules coding the same essential biological processes, while their gene contents have diverged extensively between human and mouse. Conclusions: Our results suggest that unlike the composition of module, which exhibits a great difference between human and mouse, the functional organization of the corresponding modules may evolve in a more conservative manner. Most importantly, our findings imply that similar biological processes can be carried out by different sets of genes from human and mouse, therefore, the functional data of individual genes from mouse may not apply to human in certain occasions.

Global distribution of Y-chromosome haplogroup C reveals the prehistoric migration routes of African exodus and early settlement in East Asia

The regional distribution of an ancient Y-chromosome haplogroup C-M130 (Hg C) in Asia provides an ideal tool of dissecting prehistoric migration events. We identified 465 Hg C individuals out of 4284 males from 140 East and Southeast Asian populations. We genotyped these Hg C individuals using 12 Y-chromosome biallelic markers and 8 commonly used Y-short tandem repeats (Y-STRs), and performed phylogeographic analysis in combination with the published data. The results show that most of the Hg C subhaplogroups have distinct geographical distribution and have undergone long-time isolation, although Hg C individuals are distributed widely across Eurasia. Furthermore, a general south-to-north and east-to-west cline of Y-STR diversity is observed with the highest diversity in Southeast Asia. The phylogeographic distribution pattern of Hg C supports a single coastal 'Out-of-Africa' route by way of the Indian subcontinent, which eventually led to the early settlement of modern humans in mainland Southeast Asia. The northward expansion of Hg C in East Asia started similar to 40 thousand of years ago (KYA) along the coastline of mainland China and reached Siberia similar to 15 KYA and finally made its way to the Americas. Journal of Human Genetics (2010) 55, 428-435; doi:10.1038/jhg.2010.40; published online 7 May 2010

Assessment of cattle genetic introgression into domestic yak populations using mitochondrial and microsatellite DNA markers

Hybridization between yak Poephagus grunniens and taurine Bos taurus or indicine B. indicus cattle has been widely practiced throughout the yak geographical range, and gene flow is expected to have occurred between these species. To assess the impact of cattle admixture on domestic yak, we examined 1076 domestic yak from 29 populations collected in China, Bhutan, Nepal, India, Pakistan, Kyrgyzstan, Mongolia and Russia using mitochondrial DNA and 17 autosomal microsatellite loci. A cattle diagnostic marker-based analysis reveals cattle-specific mtDNA and/or autosomal microsatellite allele introgression in 127 yak individuals from 22 populations. The mean level of cattle admixture across the populations, calculated using allelic information at 17 autosomal microsatellite loci, remains relatively low (mY(cattle) = 2.66 +/- 0.53% and Q(cattle) = 0.69 +/- 2.58%), although it varies a lot across populations as well as among individuals within population. Although the level of cattle admixture shows a clear geographical structure, with higher levels of admixture in the Qinghai-Tibetan Plateau and Mongolian and Russian regions, and lower levels in the Himalayan and Pamir Plateau region, our results indicate that the level of cattle admixture is not significantly correlated with the altitude across geographical regions as well as within geographical region. Although yak-cattle hybridization is primarily driven to produce F-1 hybrids, our results show that the subsequent gene flow between yak and cattle took place and has affected contemporary genetic make-up of domestic yak. To protect yak genetic integrity, hybridization between yak and cattle should be tightly controlled.

Proteomic Analysis of Proteins Involved in Spermiogenesis in Mouse

Spermiogenesis is a unique process in mammals during which haploid round spermatids mature into spermatozoa in the testis. Its successful completion is necessary for fertilization and its malfunction is an important cause of male infertility. Here, we report the high-confidence identification of 2116 proteins in mouse haploid germ cells undergoing spermiogenesis: 299 of these were testis-specific and 155 were novel. Analysis of these proteins showed many proteins possibly functioning in unique processes of spermiogenesis. Of the 84 proteins annotated to be involved in vesicle-related events, VAMP4 was shown to be important for acrosome biogenesis by in vivo knockdown experiments. Knockdown of VAMP4 caused defects of acrosomal vesicle fusion and significantly increased head abnormalities in spermatids from testis and sperm from the cauda epididymis. Analysis of chromosomal distribution of the haploid genes showed underrepresentation on the X chromosome and overrepresentation on chromosome 11, which were due to meiotic sex chromosome inactivation and expansion of testis-expressed gene families, respectively. Comparison with transcriptional data showed translational regulation during spermiogenesis. This characterization of proteins involved in spermiogenesis provides an inventory of proteins useful for understanding the mechanisms of male infertility and may provide candidates for drug targets for male contraception and male infertility.

Bacillus pallidus sp nov., isolated from forest soil

A Gram-positive bacterium, designated strain CW 7(T), was isolated from forest soil in Anhui Province, south-east China. Cells were strictly aerobic, motile with peritrichous flagella and rod-shaped. The strain grew optimally at 30-37 degrees C and pH 7.0-8.0. The major fatty acids of strain CW 7(T) were anteiso-C-15:0, iso-C-15:0 and anteiso-C-17:0. The predominant menaquinone was MK-7. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The G + C content of the genomic DNA was 42.3 mol%. Phylogenetic analysis indicated that strain CW 7(T) belonged to a monophyletic cluster within the genus Bacillus and showed 16S rRNA gene sequence similarities of less than 96.5% to recognized species of the genus Bacillus. The results of the polyphasic taxonomic study, including phenotypic, chemotaxonomic and phylogenetic analyses, showed that strain CW 7(T) represents a novel species of the genus Bacillus, for which the name Bacillus pallidus sp. nov. is proposed. The type strain is CW 7(T) (=KCTC 13200(T)=CCTCC AB 207188(T)=LMG 24451(T)).