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

Variation patterns of the mitochondrial 16S rRNA gene with secondary structure constraints and their application to phylogeny of cyprinine fishes (Teleostei : Cypriniformes)

The mitochondrial 16S ribosomal RNA (rRNA) gene sequences from 93 cyprinid fishes were examined to reconstruct the phylogenetic relationships within the diverse and economically important subfamily Cyprininae. Within the subfamily a biased nucleotide composition (A > T, C > G) was observed in the loop regions of the gene, and in stem regions apparent selective pressures of base pairing showed a bias in favor of G over C and T over A. The bias may be associated with transition-transversion bias. Rates of nucleotide substitution were lower in stems than in loops. Analysis of compensatory substitutions across these taxa demonstrates 68% covariation in the gene and a logical weighting factor to account for dependence in mutations for phylogenetic inference should be 0.66. Comparisons of varied stem-loop weighting schemes indicate that the down-weightings for stem regions could improve the phylogenetic analysis and the degree of non-independence of stem substitutions was not as important as expected. Bayesian inference under four models of nucleotide substitution indicated that likelihood-based phylogenetic analyses were more effective in improving the phylogenetic performance than was weighted parsimony analysis. In Bayesian analyses, the resolution of phylogenies under the 16-state models for paired regions, incorporating GTR + G + I models for unpaired regions was better than those under other models. The subfamily Cyprininae was resolved as a monophyletic group, as well as tribe Labein and several genera. However, the monophyly of the currently recognized tribes, such as Schizothoracin, Barbin, Cyprinion + Onychostoma lineages, and some genera was rejected. Furthermore, comparisons of the parsimony and Bayesian analyses and results of variable length bootstrap analysis indicates that the mitochondrial 16S rRNA gene should contain important character variation to recover well-supported phylogeny of cyprinid taxa whose divergences occurred within the recent 8 MY, but could not provide resolution power for deep phylogenies spanning 10-19 MYA. (c) 2008 Published by Elsevier Inc.

Molecular characterization of three Rana grylio virus (RGV) isolates and Paralichthys olivaceus lymphocystis disease virus (LCDV-C) in iridoviruses

Three Rana grylio virus (RGV) isolates and lymphocystis disease virus (LCDV-C) were molecularly characterized by antigenicity comparison, Western blot detection of viral polypeptides, restriction fragment length polymorphism analysis of viral genomes, and MCP sequence analysis. Significant antigenicity differences existed among the three RGV isolates and LCDV-C. Western blot detection indicated that the viral polypeptides of three RGV isolates could be recognized by the anti-RGV9807 serum, whereas no bands were observed in the LCDV-C, and significant differences exist among the band patterns of three RGV isolates. Restriction fragment length polymorphism (RFLP) analysis was performed by digesting genomic DNA of the four iridovirus isolates with restriction endonucleases HindIII, KpnI, XbaI and BamHI. On the whole, obvious discrepancies existed between LCDV-C and RGV isolates, and some significant band pattern differences were also revealed between RGV9808 and RGV9506 (or RGV9807) in the profiles of restriction endonucleases Xbal, Kpn I and BamHI. PCR amplification and sequence analysis of MCP gene sequence further revealed their phylogenetic relationship among the three RGV isolates, LCDV-C and other iridoviruses. RGV9506, RGV9807 and RGV9808 are clustered together with other ranaviruses, such as FV3, BIV, TFV and ENHV, although the RGV9808 is more close to EHNV than to other ranaviruses. Additionally, LCDV-C is clustered with LCDV-1, the type species of genus Lymphocystisvirus. The current study provides clear evidence that significant genetic difference exists among the three RGV isolates. Therefore, further work on comparative genomic studies will contribute significantly to understanding of their taxonomic position and pathological mechanism. (C) 2005 Elsevier B.V. All rights reserved.

Effects of TMIn flow on the interface and optical properties of InGaN/GaN mutiple quantum wells

The effects of pre-TMIn flow prior to QW growth and TMIn flow rates during QW growth on the interface and optical properties of InGaN/GaN MQWs were investigated. Pre-depositing indium prior to QW growth and an appropriate TMIn flow rate can improve the interface abruptness and increase the EL intensity. InGaN/GaN MQWs with improved interface abruptness have increasing emission intensity and wavelength. We attribute the interface improvement and the increase of EL intensity to the improvement of the indium compositional profiles. (C) 2004 Elsevier B.V. All rights reserved.

Low-temperature growth of InN by MOCVD and its characterization

Metalorganic chemical vapor deposition growth of InN on sapphire substrate has been investigated between 400 degrees C and 500 degrees C to seek the growth condition of InN buffer layer, i.e. the first step of realization of the two-step growth method. Ex situ characterization of the epilayers by means of atomic force microscope, scanning electron microscope and X-ray diffraction, coupled with in situ reflectance curves, has revealed different growth circumstances at these temperatures, and conclusion has been reached that the most suitable temperature for buffer growth is around 450 degrees C. In addition, the growth rate of InN at the optimized temperature with regard to different precursor flow rates is studied at length. (c) 2004 Elsevier B.V. All rights reserved.

Study on the hydrolysis/precipitation behavior of Keggin Al-13 and Al-30 polymers in polyaluminum solutions

The hydrolysis/precipitation behaviors of Al3+, Al-13 and Al-30 under conditions typical for flocculation in water treatment were investigated by studying the particulates' size development, charge characteristics, chemical species and speciation transformation of coagulant hydrolysis precipitates. The optimal pH conditions for hydrolysis precipitates formation for AlCl3, PAC(A113) and PAC(A130) were 6.5-7.5, 8.5-9.5, and 7.5-9.5, respectively. The precipitates' formation rate increased with the increase in dosage, and the relative rates were AlCl3 >> PAC(A130) > PACA113. The precipitates' size increased when the dosage increased from 50 mu M to 200 mu M, but it decreased when the dosage increased to 800 AM. The Zeta potential of coagulant hydrolysis precipitates decreased with the increase in pH for the three coagulants. The isoelectric points of the freshly formed precipitates for AlCl3, PAC(A113) and PAC(A130) were 7.3, 9.6 and 9.2, respectively. The Zeta potentials of AlCl3 hydrolysis precipitates were lower than those of PAC(A113) and PAC(A130) when pH > 5.0. The Zeta potential of PAC(A130) hydrolysis precipitates was higher than that of PACA113 at the acidic side, but lower at the alkaline side. The dosage had no obvious effect on the Zeta potential of hydrolysis precipitates under fixed pH conditions. The increase in Zeta potential with the increase in dosage under uncontrolled pH conditions was due to the pH depression caused by coagulant addition. Al-Ferron research indicated that the hydrolysis precipitates of AlCl3 were composed of amorphous AI(OH)3 precipitates, but those of PACA113 and PACA130 were composed of aggregates of Al-13 and Al-30, respectively. Al3+ was the most un-stable species in coagulants, and its hydrolysis was remarkably influenced by solution pH. Al-13 and Al-30 species were very stable, and solution pH and aging had little effect on the chemical species of their hydrolysis products. The research method involving coagulant hydrolysis precipitates based on Al-Ferron reaction kinetics was studied in detail. The Al species classification based on complex reaction kinetic of hydrolysis precipitates and Ferron reagent was different from that measured in a conventional coagulant assay using the Al--Ferron method. The chemical composition of Al-a, Al-b and Al-c depended on coagulant and solution pH. The Al-b measured in the current case was different from Keggin Al-13, and the high Alb content in the AlCl3 hydrolysis precipitates could not used as testimony that most of the Al3+ Was converted to highly charged Al-13 species during AlCl3 coagulation.

Methods for physical separation and characterization of soil organic matter fractions

Turnover of soil organic matter (SOM) is coupled to the cycling of nutrients in soil through the activity of soil microorganisms. Biological availability of organic substrate in soil is related to the chemical quality of the organic material and to its degree of physical protection. SOM fractions can provide information on the turnover of organic matter (OM), provided the fractions can be related to functional or structural components in soil. Ultrasonication is commonly used to disrupt the soil structure prior to physical fractionation according to particle size, but may cause redistribution of OM among size fractions. The presence of mineral particles in size fractions can complicate estimations of OM turnover time within the fractions. Densiometric separation allows one to physically separate OM found within a specific size class from the heavier-density mineral particles. Nutrient contents and mineralization potential were determined for discrete size/density OM fractions isolated from within the macroaggregate structure of cultivated grassland soils. Eighteen percent of the total soil C and 25% of the total soil N in no-till soil was associated with fine-silt size particles having a density of 2.07-2.21 g/cm3 isolated from inside macroaggregates (enriched labile fraction or ELF). The amount of C and N sequestered in the ELF fraction decreased as the intensity of tillage increased. The specific rate of mineralization (mug net mineral N/mug total N in the fraction) for macroaggregate-derived ELF was not different for the three tillage treatments but was greater than for intact macroaggregates. The methods described here have improved our ability to quantitatively estimate SOM fractions, which in turn has increased our understanding of SOM dynamics in cultivated grassland systems.

Hydrogen Bonding and Crystallization in Biodegradable Multiblock Poly(ester urethane) Copolymer

The hydrogen bonding and crystallization of a biodegradable poly(ester urethane) copolymer based on poly(L-lactide) (PLLA) as the soft segment were investigated by FTIR. On slow cooling from melt, the onset and the progress of the crystallization of the urethane hard segments were correlated to the position, width, and relative intensity of the hydrogen-bonded N-H stretching band. The interconversion between the "free" and hydrogen-bonded N-H and C=O groups in the urethane units in the process was also revealed by 2D correlation analysis of the FTIR data. The crystallization of the PLLA soft segments was monitored by the ester C=O stretching and the skeletal vibrations. It was revealed that the PLLA crystallization was restricted by the phase separation and the urethane crystallization, and at cooling rates of 10 degrees C/min or higher, the crystallization of the PLLA soft segments was prohibited.

Crystallization behavior of poly(epsilon-caprolactone) in poly(epsilon-caprolactone) and poly(vinyl methyl ether) mixtures

The morphological development and crystallization behavior of poly(epsilon-caprolactone) (PCL) in miscible mixtures of PCL and poly(vinyl methyl ether) (PVME) were investigated by optical microscopy as a function of the mixture composition and crystallization temperature. The results indicated that the degree of crystallinity of PCL was independent of the mixture composition upon melt crystallization because the glass-transition temperatures of the mixtures were much lower than the crystallization temperature of PCL. The radii of the PCL spherulites increased linearly with time at crystallization temperatures ranging from 42 to 49 degrees C. The isothermal growth rates of PCL spherulites decreased with the amount of the amorphous PVME components in the mixtures. Accounting for the miscibility of PCL/PVME mixtures, the radial growth rates of PCL spherulites were well described by a kinetic equation involving the Flory-Huggins interaction parameter and the free energy for the nuclei formation in such a way that the theoretical calculations were in good agreement with the experimental data. From the analysis of the equilibrium melting point depression, the interaction energy density of the PVME/PCL system was calculated to be -3.95 J/cm(3).

Syntheses of fully sulfonated polyaniline nano-networks and its application to the direct electrochemistry of cytochrome c

Fully sulfonated polyaniline nano-particles, nano-fibrils and nano-networks have been achieved for the first time by electrochemical homopolymerization of orthanilic acid using a three-step electrochemical deposition procedure in a mixed solvent of acetonitrile (ACN) and water. The diameter of the uniform nano-particles is about 60nm, and the nano-fibrils can be organized in two-dimensional (21)) or three-dimensional (313) non-periodic networks with good electrical contact. Average distance between contacts is about 850 and 600 nm for a 2D and 3D system, respectively. The details of the poly(orthanilic acid) (POA) nano-structure were examined with a field emission scanning electron microscope (SEM). The structure and properties of POA were characterized with FTIR, UV-vis and electrochemical methods. The 3D POA nano-networks coated platinum electrode gave a direct electrochemical behavior of horse heart cytochrome c (Cyt c) immobilized on this electrode surface, a pair of well-defined redox waves with formal potential (E-ol) of -0.032 V (versus Ag/AgCl) was achieved. The interaction between Cyt c and POA makes the formal potential shift negatively compared to that of Cyt c in solution. Spectrophotometric and electrochemical methods were used to investigate the interaction of Cyt c with POA.

Isothermal and non-isothermal crystallization kinetics of syndiotactic polypropelene

Isothermal and non-isothermal crystallization kinetics of a syndiotactic polypropylene(sPP) sample synthesized by new metallocene catalyst at different annealing temperatures and different cooling rates have been investigated by using differential scanning calorimetry(DSC) and density analysis. The equilibrium melting temperature( T-m(0)) is 158 degrees C by Hoffman-Weeks method. The equilibrium heat of fusion(Delta H-m(0)) is 88J/g in terms of the density analysis and DSC methods. The lateral and end surface free energies derived from the Lauritzen-Hoffman spherulitic growth rate equation are sigma = 5.2erg/cm(2) and sigma(e) = 69erg/cm(2), respectively. The work of chain folding is determined to be q = 33.75kJ/mol. Modified Avrami equation and Ozawa equation can be used to describe the non-isothermal crystallization behavior. And a new and convenient approach by combining the Avrami equation and Ozawa equation in a same crystallinity is used to describe the non-isothermal behavior as well. The crystallization activation energies are evaluated to be 73.7kJ/mol and 73.1kJ/mol for isothermal crystallization and non-isothermal crystallization, respectively. The Avrami exponent n is 1.5 similar to 1.6 for isothermal crystallization procedure, while the Avrami exponent n,is 2.5 similar to 3.5 for non-isothermal crystallization procedure. This indicated the difference of nucleation and growth between the two procedures.

The rheological and extrusion behaviour of blends based on phenolphthalein poly(ether-ether-sulfone) and thermotropic liquid crystalline polymer

A novel engineering thermoplastic, phenolphthalein poly (ether-ether-sulfone) (PES-C) was blended with a commercial thermotropic liquid crystalline polymer(TLCP), Vectra A950, up to 30 weight percent of TLCP. A rheometrics dynamic spectrometer (RDS-I) and a CEAST capillary rheometer, a rheoscope 1000 were employed to investigate the melt rheology and extrusion behaviour at both the low and high shearing rates. The morphologies of the blends under different shearing were observed with a scanning electron microscope(SEM) and correlated to the observed rheology. The principal normal stress differences measured with cone-and-plate geometry give a temperature-independent correlation for both blend and PES-C when they are plotted against shear stress. But the extrudate swell of the blends showed a strong temperature dependence at each shear stress. The concentration dependence of extrudate swell shows a contrary behaviour to that of the inorganic filled system. A reasonable hypothesis based on the relaxation and disorientation of TLCP during flowing in the capillary and exiting was given to explain it. The melt fracture was checked after extrusion from capillary and was discussed.

Tip-induced dynamic characterization of multilayers and variable morphologies of cytochrome c molecules on highly oriented pyrolytic graphite revealed by in-situ scanning tunnelling microscopy

The dynamic states of cytochrome c multilayers on electrochemically pretreated highly oriented pyrolytic graphite (HOPG) have been studied by in-situ scanning tunnelling microscopy (STM) under potential control of both the tip and the substrate in cytochrome c and phosphate buffer solution. The dynamic characterization of cytochrome c multilayers and relatively stable adsorbed single cytochrome c molecules scattered on HOPG imply that physically adsorbed multilayers were more easily influenced by the STM tip than those of chemically adsorbed single molecules. In-situ STM images of chemically adsorbed cytochrome c molecules with discernible internal structures on HOPG revealed that morphologies of cytochrome c molecules also suffered tip influence; possible tip-sample-substrate interactions have been discussed.

Poly(epsilon-caprolactone)/poly(ethylene oxide) diblock copolymer .1. Isothermal crystallization and melting behavior

The isothermal crystallization and melting behavior of the poly(epsilon-caprolactone) (PCL)/poly(ethylene oxide)(PEO) diblock copolymer has been studied by WAXD, SAXS, and DSC methods. Only the PCL block is crystallizable; the PEO block of weight fraction 20% cannot crystallize, although its corresponding homopolymer has strong crystallizability. The long period, amorphous layer, and crystalline lamella of the PCL/PEO block copolymer all increase with the rise in the crystallization temperature, and the thickness of the amorphous layer is much larger than that of crystalline lamella due to the existence of the PEO block in the amorphous region. The isothermal crystallization of the PCL/PEO block copolymer is investigated by using the theory of Turnbull and Fischer. It is found that the amorphous PEO block has a great influence on the nucleation of PCL block crystallization, and the extent of this influence depends on crystallization conditions, especially temperature. The outstanding characteristics are the phenomenon of the double melting peaks in the melting process of the PCL/PEO block copolymer after isothermal crystallization at different temperatures and the transformation of melting peaks from double peaks to a single peak with variations in the crystallization condition. They are related mainly to the existence of the PEO block bonding chemically with the PCL block. In summing up results of investigations into the crystallization and melting behavior of the PCL/PEO block copolymer, it is interesting to notice that when the PCL/PEO block copolymer crystallizes at three different crystallization temperatures, i.e., below 0 degrees C, between 0 and 35 degrees C, and above 35 degrees C, the variation of peak melting temperature is similar to that of overall crystallization rates in the process of isothermal crystallization. The results can be elucidated by the effect of the PEO block on the crystallization of the PCL block, especially its nucleation. (C) 1996 John Wiley & Sons, Inc.

Effects of ultra-violet irradiation on sperm motility and diploid gynogenesis induction in large yellow croaker (Pseudosciaena crocea) undergoing cold shock

Large yellow croaker, Pseudosciaena crocea, exhibit sexually dimorphic growth, with females growing faster and reaching larger adult sizes than males. Thus, development of techniques for preferentially producing females is necessary to optimize production of these species. We have established a protocol to produce all-female croaker P. crocea through induction of meiotic gynogenesis with homologous sperm. The first set of experiments investigated the ultra-violet (UV) irradiation on sperm motility and duration of sperm activity to determine the optimal UV dosage for genetic inactivation of sperm, yet retaining adequate motility for activation of eggs. Milt from several males was diluted 1: 100 with Ringer's solution and UV irradiated with doses ranging from 0-150 J cm (-2). The results indicated that motility and duration of activity generally decreased with increased UV doses. At UV doses greater than 105 J cm(-2), after fertilization, motility was < 10% and fertilization rates were significantly lower. Highest hatching rate was obtained at 75 J cm -2. A second set of experiments was carried out to determine appropriate conditions of cold shock for retention of the 2nd polar body in P. crocea eggs after fertilization with UV-inactivated sperm by altering the timing, temperature and duration of shock. At 208 degrees C, shock applied at 3 min after fertilization resulted in higher survival rate of larvae at 6 h after hatching. Results of different combinations of three shock temperatures ( 28 degrees C, 38 degrees C or 48 degrees C) and five shock durations ( 4 min, 8 min, 12 min, 16 min or 20 min) at 3 min after fertilization demonstrated that shocks of 12 min gave highest production of diploid gynogens. Statistical analysis revealed that maximum production of diploid gynogens (44.55 +/- 2.99%) were obtained at 38 degrees C. The results of this study indicate that the use of UV-irradiated homologous sperm for activation of P. crocea eggs and cold shock for polar body retention is an effective method for producing gynogenetic offspring.