The dependence of structural stability and tunable gap on the Si components of ZnSe/Si bi-coaxial nanowire heterostructures

The bare and hydrogen-passivated ZnSe/Si bi-coaxial nanowire heterostructures along [110] direction have been investigated by using the first-principle calculations within density functional theory. The structural stability and electronic property of ZnSe/Si bi-coaxial nanowire heterostructures have been shown by changing the Si components. It is found that the ZnSe/Si nanowires have zero gaps at lower Si components, and then they have the increasing gap at higher Si components. It is seen clearly that there is the transition of band gap form zero to nonzero. With increasing Si components, the ZnSe/Si nanowires can be also achieved as n-type or p-type, in agreement qualitatively with the experimental observations. In addition, the structural stabilities and the cohesive energies of ZnSe/Si bi-coaxial nanowires are changed obviously with the different Si components.

No primexine and plasma membrane undulation is essential for primexine deposition and plasma membrane undulation during microsporogenesis in Arabidopsis

Primexine deposition and plasma membrane undulation are the initial steps of pollen wall formation. However, little is known about the genes involved in this important biological process. Here, we report a novel gene, NO PRIMEXINE AND PLASMA MEMBRANE UNDULATION (NPU), which functions in the early stage of pollen wall development in Arabidopsis (Arabidopsis thaliana). Loss of NPU function causes male sterility due to a defect in callose synthesis and sporopollenin deposition, resulting in disrupted pollen in npu mutants. Transmission electronic microscopy observation demonstrated that primexine deposition and plasma membrane undulation are completely absent in the npu mutants. NPU encodes a membrane protein with two transmembrane domains and one intracellular domain. In situ hybridization analysis revealed that NPU is strongly expressed in microspores and the tapetum during the tetrad stage. All these results together indicate that NPU plays a vital role in primexine deposition and plasma membrane undulation during early pollen wall development.

Recipient outcomes after ABO-incompatible liver transplantation: a systematic review and meta-analysis

Background

ABO-incompatible live transplantation (ILT) is not occasionally performed due to a relative high risk of graft failure. Knowledge of both graft and patient survival rate after ILT is essential for donor selection and therapeutic strategy. We systematically reviewed studies containing outcomes after ILT compared to that after ABO-compatible liver transplantation (CLT).

Methodology/Principal Findings

We carried out a comprehensive search strategy on MEDLINE (1966–July 2010), EMBASE (1980–July 2010), Biosis Preview (1969–July 2010), Science Citation Index (1981–July 2010), Cochrane Database of Systematic Reviews (Cochrane Library, issue 7, 2010) and the National Institute of Health (July 2010). Two reviewers independently assessed the quality of each study and abstracted outcome data. Fourteen eligible studies were included which came from various medical centers all over the world. Meta-analysis results showed that no significantly statistical difference was found in pediatric graft survival rate, pediatric and adult patient survival rate between ILT and CLT group. In adult subgroup, the graft survival rate after ILT was significantly lower than that after CLT. The value of totally pooled OR was 0.64 (0.55, 0.74), 0.92 (0.62, 1.38) for graft survival rate and patient survival rate respectively. The whole complication incidence (including acute rejection and biliary complication) after ILT was higher than that after CLT, as the value of totally pooled OR was 3.02 (1.33, 6.85). Similarly, in acute rejection subgroup, the value of OR was 2.02 (1.01, 4.02). However, it was 4.08 (0.90, 18.51) in biliary complication subgroup.

Conclusions/Significance

In our view, pediatric ILT has not been a contraindication anymore due to a similar graft and patient survival rate between ILT and CLT group. Though adult graft survival rate is not so satisfactory, ILT is undoubtedly life-saving under exigent condition. Most studies included in our analysis are observational researches. Larger scale of researches and Randomized-Control Studies are still needed.

[Detection, verification and significance of differentially expressed miRNAs in bladder urothelial carcinoma]

OBJECTIVE

To explore the differentially expressed miRNAs in bladder urothelial carcinoma (BUC) in order to provide rationales for further studies of function and mechanism for their actions.

METHODS

Fresh normal (5 samples) and BUC (30 samples) tissues were collected from September 2008 to September 2009 in our hospital and analyzed by miRNA microarray to find differentially expressed miRNAs; RT-PCR (reverse transcription-polymerase chain reaction) of recollected samples and 4 types of cell strain to verify the selected miRNAs.

RESULTS

In grade I, grade II, grade III, grade I + II + III, infiltrating and non-infiltrating groups, hsa-miR-29b-1 was up-regulated while hsa-miR-923 and hsa-miR-300 were down-regulated. When the infiltrating BUC group was compared with the non-infiltrating BUC group, there were 7 differentially expressed miRNAs. In collected samples, the result of RT-PCR was consistent with that of miRNA array. In 4 types of cancer cell strains, only the result of T24 was completely consistent with that of miRNA array.

CONCLUSIONS

There are differentially expressed miRNAs between normal bladder mucosa and BUC, infiltration BUC and non-infiltration BUC. The result of T24 cell strain is completely consistent with that of miRNA array.

[Effect and mechanism of Aconitum vaginatum on the proliferation, invasion and metastasis in human A549 lung carcinoma cells]

OBJECTIVE

To study the effects and mechanism of Aconitum vaginatum on proliferation, invasion and metastasis of human lung adenocarcinoma A549 cell lines.

METHODS

A549 cells were treated with Aconitum vaginatum at different concentrations, and divided into 4 groups: Aconitum vaginatum 0.01, 0.1, 1 mg/mL groups and control group, respectively. MTT assay was used to evaluate cell proliferation; migration and invasion (with matrigel) assay was conducted in the transwell chamber; gelatin zymography was performed to evaluated the impacts of Aconitum vaginatum on matrix metalloproteinase (MMP)-2, MMP-9.

RESULTS

Aconitum vaginatum exhibited a concentration-dependent inhibitory on proliferation and invasion of A549 cells. Aconitum vaginatum was also found to decrease the activity of MMP-2, MMP-9 in a concentration-dependent manner (P < 0.05).

CONCLUSION

Aconitum vaginatum can inhibit the proliferation, invasion and metastasis of human adenocarcinoma A549 cell lines, the mechanism maybe deceasing MMP-2, MMP-9 activity.

Scale and twist effects on the strength of nanostructured yarns and reinforced composites

In this work we investigate the effects of yarn diameter and gauge length on the statistical strength of yarns spun from carbon nanotubes (CNTs). Tensile tests are conducted on a large sample set of nanostructured CNT yarns. The data show that strength varies substantially and both strength and statistical dispersion in strength decreases as yarn diameter increases. To explain these phenomena and forecast their effects on larger-scale structures, a hierarchical set of Monte Carlo simulation models is developed: the lower-scale model aims to predict the relationship between yarn nanostructure and tensile strength and the higher-scale model aims to relate the strength of CNT yarns to the strength of composites reinforced with unidirectionally aligned CNT yarns. Predictions indicate that, for both structures, the mean and statistical variation in strength will decrease as the surface twist angle, number of CNTs in cross section and gauge length of the yarn increases. The predicted reductions in variability due to yarn nanostructure will be important for determining ways to minimize the detrimental effects of increasing length scale on strength.

Photoreactivity of a push-pull merocyanine in static electric fields: a three-state model of isomerization reactions involving conical intersections

The photochemistry of a prototype push-pull merocyanine is discussed using a simple three-state model. As a derivative of butadiene, the model focuses on two isomerization reactions around the two double bonds of the butadiene backbone. As a molecule substituted by an electron donor and electron acceptor at opposite ends, its structure as well as its photochemistry are expected to be strongly affected by the environment. In polar solvents, a zwitterion transition state for each of the isomerization reactions is stabilized, and its energy is on the same order as that of the biradical one; this leads to the symmetry allowed crossing (S(0)/S(1) conical intersection). It is shown that applying an external electric field or varying the solvent polarity changes the relative energies of the different transition states as well as that of the conical intersection, and thus different photochemical products can be obtained. In particular, the very existence of conical intersections is found to depend on these external parameters. This work provides a theoretical foundation for ideas expressed by Squillacote et al. (J. Am. Chem. Soc. 2004, 126, 1940) concerning the electrostatic control of photochemical reactions.

Myosin Vc, a member of the actin motor family associated with Rab8, is involved in the release of DV2 from HepG2 cells

OBJECTIVE

The pathogenesis of the dengue virus (DV) infection has not been well defined. We have reported that actin and Rab8 are involved in DV2 infection. Myosin Vc (Myo5c) is a novel member of the class V myosins and regulates the actin-mediated membrane trafficking associated with Rab8. In this study, the involvement of Myo5c in the release of DV2 was investigated in HpeG2 cells.

METHODS

Distributions of actin, Myo5c, DV2 and Rab8 were revealed by fluorescent staining. HepG2(Myo5c-tail) cells expressing a dominant-negative mutant of Myo5c were constructed by transfection and were assessed by Western blotting. The viral titers were detected by plaque assay, and the expression of Rab8 was analyzed by flow cytometry.

RESULTS

DV2 infection altered the distribution pattern of Myo5c, which might be associated with the depolymerization of actin, though colocalization rates of Myo5c with DV2 or actin were low. Furthermore, the release of DV2, but not the intracellular viral production, was reduced from HepG2(Myo5c-tail) cells. Moreover, Myo5c colocalized with Rab8 and an increase of Rab8 was associated with the decrease of the viral release caused by the Myo5c tail.

CONCLUSIONS

Our data suggest that Myo5c associated with Rab8 is involved in the release of DV2 from HepG2 cells.

Entry of dengue virus serotype 2 into ECV304 cells depends on clathrin-dependent endocytosis, but not on caveolae-dependent endocytosis

Caveolae- and clathrin-mediated endocytosis are major internalization pathways used by several pathogens; however, their distinctive roles in dengue virus (DV) entry have not been addressed. In this study, we compared the involvement of caveolae- and clathrin-mediated endocytosis in the infectious entry of DV serotype 2 (DV2) into human endothelial-like ECV304 cells. Confocal microscopy study on DV2-infected cells showed that viral antigens were co-localized with clathrin heavy chains, epidermal growth factor pathway substrate clone 15 (Eps15), and adaptin-alpha, but not with caveolin-1. Treatment with chlorpromazine, which inhibits clathrin-dependent endocytosis, led to reduced virus entry into cells, whereas treatment with nystatin, a caveolae inhibitory agent, did not. Furthermore, gene silencing of Eps15 resulted in an average of 75% reduced infection of ECV304 cells by DV2. Our results demonstrated that DV2 enters ECV304 cells by clathrin-dependent endocytosis, not by caveolae-dependent endocytosis.

The prevalence of household second-hand smoke exposure and its correlated factors in six counties of China

Objective:

To study the prevalence of, and discuss factors contributing to, household second-hand smoke exposure in six counties in China, providing scientific support for the need to establish tobacco control measures in these areas.

Methods:

A cross-sectional survey was performed. Investigators conducted face-to-face interviews using a standardised questionnaire to collect information on demographics, passive smoking behaviours and knowledge, and attitudes towards tobacco control. The setting was six counties from the three provinces: Mianzhu and Xichong counties in Sichuan Province; Anyi and Hukou counties in Jiangxi Province; and Xinan and Yanshi counties in Henan Province. A total of 8142 non-smokers (aged 18–69) in 2004 were included in the data analysis. Household second-hand smoke exposure rate as defined as the proportion of household passive smokers in the non-smoker population was used as the measure of household second-hand smoke exposure.

Results:

The analysis of 8142 non-smokers revealed that, in these selected counties, the household second-hand smoke exposure rate was 48.3%. Respondents had positive attitudes towards tobacco control. Of 6972 respondents, 84.4% supported all the three tobacco control policies (banning smoking in public places, banning the selling of cigarettes to minors, banning all cigarette advertisements). In 3165 families with smokers, 87.2% of respondents reported that smokers would smoke in front of them. In 2124 families with smokers and children, 76.5% of respondents reported that smokers would smoke in front of children. As many as 42.1% of non-smokers would offer cigarettes to their guests, and only 46.8% of respondents would ask smokers to smoke outdoors. Only 6.3% of families completely forbade smoking at home. Multivariate logistic regression analysis revealed high second-hand smoke exposure for the following demographic groups: Jiangxi Province inhabitants, females, those with low education level, farmers and married respondents.

Conclusions:

Household second-hand smoke exposure rates in the selected counties were high. A high percentage of respondents reported that smokers would smoke in front of them and children. The pressure from non-smokers against smoking was relatively low, although offering cigarette was prevalent. Households that were completely smoking-free were rare, Further studies on these correlated factors could help us establish effective measures to reduce household second-hand smoke exposure.

Digital oedema, adhesion formation and resistance to digital motion after primary flexor tendon repair

The development of digital oedema, adhesion formation, and resistance to digital motion at days 0, 3, 5, 7, 9 and 14 after primary flexor tendon repairs using 102 long toes of 51 Leghorn chickens was studied. Oedema presented as tissue swelling from days 3 to 7, which peaked at day 3. After day 7, oedema was manifest as hardening of subcutaneous tissue. The degree of digital swelling correlated with the resistance to tendon motion between days 3 and 7. At day 9, granulation tissues were observed around the tendon and loose adhesions were observed at day 14. Resistance to digital motion increased significantly from day 0 to day 3, but did not increase between days 3 and 9. The early postoperative changes appear to have three stages: initial (days 0-3, increasing resistance with development of oedema), delayed (days 4-7, higher resistance with continuing oedema) and late (after day 7-9, hardening of subcutaneous tissue with development of adhesions).

Band-dependent normal-state coherence in Sr2RuO4: evidence from Nernst effect and thermopower measurements

We present the first measurement on the Nernst effect in the normal state of the odd-parity, spin-triplet superconductor Sr2RuO4. Below 100 K, the Nernst signal was found to be negative, large, and, as a function of magnetic field, nonlinear. Its magnitude increases with the decreasing temperature until reaching a maximum around T* approximately equal to 20-25 K, below which it starts to decrease linearly as a function of temperature. The large value of the Nernst signal appears to be related to the multiband nature of the normal state and the nonlinearity to band-dependent magnetic fluctuation in Sr2RuO4. We argue that the sharp decrease in the Nernst signal below T* is due to the suppression of quasiparticle scattering and the emergence of band-dependent coherence in the normal state.

Security enhancement of double-random phase encryption by amplitude modulation

Conventional double-random phase encoding is vulnerable to a chosen or known plaintext attack owing to the linearity of the system. We introduce a technique to break down this linearity with an undercover amplitude modulation in the encryption scheme. As an additional key, this operation can significantly enhance the security of the system. A series of computer simulations have shown the effectiveness of this method and its resistance against the known plaintext attack. The design and parameter choice of the amplitude modulator is also discussed.

Simple direct extraction of unknown phase shift and wavefront reconstruction in generalized phase-shifting interferometry: algorithm and experiments

An algorithm to extract the arbitrary unknown phase shift and then reconstruct the complex object wave in generalized phase-shifting interferometry (GPSI) without the iteration process and measurement of object wave intensity is proposed. This method can be used for GPSI of any frame number >or=2. Both computer simulations with smooth and diffusing object surfaces and optical experiments have verified the effectiveness of this method over a wide range of phase shifts with very satisfactory results.

The gliding force and work of flexion in the early days after primary repair of lacerated flexor tendons: an experimental study

We measured the resistance to tendon mobilisation within the first 5 days after primary repair of digital flexor tendons of chickens. Forty-six long toes of 23 chickens were assigned to six surgical groups and one unoperated control group. The tendons were partially lacerated and surgically repaired. The resistance to simulated active digital flexion was assessed in six operated groups at 0, 1, 2, 3, 4 and 5 days postoperatively. The force of tendon motion and work of flexion increased gradually from day 0 to day 5. The force and work at days 4 and 5 were significantly higher than those at days 0 and 1. No statistical difference was found in the resistance at days 0, 1, 2 and 3. Our results indicate that the gliding resistance gradually increases over the first 5 days after surgery and suggest that tendon motion may be started after the first 3 days, to avoid moving during this period of increased resistance with increased risk of tendon rupture.

RNA interference-mediated silencing of the PAR gene inhibits the growth of PC3 cells via the induction of G2/M cell cycle arrest and apoptosis

BACKGROUND

The prostate androgen-regulated (PAR) gene is ubiquitously overexpressed in prostate cancer (PCa) cells and is involved in proliferation of PCa. However, the mechanism by which the modulation of PAR gene expression elicits its biological effects on PCa cells is not well documented. Here, we investigate the mechanism of PAR depletion inhibiting PCa cell growth.

METHODS

PAR expression was depleted by small interfering RNA (siRNA) and its subsequent effects on proliferation of PC3 cells were determined by the trypan blue exclusion assay. Flow cytometric analysis provided the evidence for the progression of cell cycle and the induction of apoptosis which was further confirmed by the observation of cleavage of poly(ADP-ribose) polymerase. Western blot analysis was performed to investigate the involvement of critical molecular events known to regulate the cell cycle and the apoptotic machinery.

RESULTS

siRNA transfection results in a dose-dependent inhibition of cell growth in PC3 cells by causing G2/M phase cell cycle arrest and apoptosis. The G2/M arrest by PAR depletion was associated with decreased levels of cyclin B1, pCdc2 (Tyr15), Cdc2 and Cdc25C. PAR depletion also was found to result in inhibition of procaspases 9, 8, 6 and 3 with significant increase in the ratio of Bax : Bcl-2.

CONCLUSIONS

Our data indicate that PAR depletion induces G2/M arrest via the Cdc25C-Cdc2/cyclin B1 pathway. Furthermore, the results of the present study point toward involvement of pathways mediated by both caspase 8 and caspase 9 in apoptosis induction by PAR depletion.

Effects of myakuryu on hemorheological characteristics and mesenteric microcirculation of rats fed with a high-fat diet

There is evidence that hyperlipidemia can induce hemorheological and microcirculatory disturbances. Myakuryu, a Chinese traditional medicine is efficacious in promoting lipid metabolism and protecting oxidative stress, but whether this drug can ameliorate rheologic disturbances caused by hyperlipidemia is still unknown. The present study was conducted to investigate the effects of myakuryu on hemorheological and microcirculatory disturbances induced by hyperlipidemia. Wistar rats were divided into a group on control diet (n=8) and a group on high-fat diet (HFD, n=44). Eight weeks later, plasma triglyceride (TG) and total cholesterol (TC) were determined. Sixteen animals with the highest levels of hyperlipidemia from the HFD group were randomly divided into two sub-groups: the untreated hyperlipidemia group (n=8) and the group treated with myakuryu (n=8). At the end of the sixteenth week, rheological and microcirculatory parameters were measured. Chemical analysis showed that myakuryu treatment caused significant reductions of plasma TG and TC levels (P<0.01), and the cholesterol/phospholipid ratio in the erythrocyte membrane (P<0.05). Rheological and microcirculatory measurements showed that myakuryu treatment led to a significant decrease in the erythrocyte aggregation index, plasma viscosity and blood viscosity at shear rates of 50, 100 and 150 s(-1) and in adherent leukocytes in mesenteric venules. There was a significant increase in erythrocyte deformation, electrophoretic mobility, membrane fluidity and F-actin content in the erythrocyte membrane as well as in red cell velocity in mesenteric venules. Our findings suggest that myakuryu treatment can improve blood flow and reduce adherent leukocytes in the venules of rats fed with HFD by ameliorating blood viscosity, erythrocyte deformability and aggregation, and other hemorheological characteristics.

[Research progress in epigenetics of sperm]

Epigenetics is defined as the study of the heritable phenotype change that is not strictly dependent on DNA sequence. It involves DNA methylation, histone modifications, regulations of non-coding RNAs, and so on. Great epigenetic changes take place during the spermatogenesis and fertilization, so it is very important for us to understand the epigenetic messages. This paper provides an overview of the latest researches on epigenetics of male germ cells, and briefly discusses the possible genetic risks of the assisted reproductive technology (ART).

Negative refractions in two-dimensional photonic crystals formed by holographic lithography

We present a study on negative refractions in the four lowest bands of two-dimensional (2D) square lattices formed by holographic lithography (HL) and compare these features with those of a lattice of the same kind but with regular dielectric columns. The plane wave calculations and FDTD simulations have shown that in some bands or for some interfaces the negative refraction can only happen in holographic structures, and generally the rightness of holographic structures and regular structures of the same kind may be different.

Holographic design and band gap evolution of photonic crystals formed with five-beam symmetric umbrella configuration

We propose a holographic design of five-beam symmetric umbrella configuration, where there are a central beam and four ambient beams symmetrically scattered around the central one with the same apex angle, for fabrication of three-dimensional photonic crystals with tetragonal or cubic symmetries, and systematically analyzed the band gap properties of resultant photonic crystals when the apex angle is continuously increased. Our calculations reveal that large complete photonic band gaps exist in a wide range of apex angle for a relatively low refractive index contrast. Specifically, the face-centered cubic structure with a relative band gap of 25.1% for epsilon = 11.9 can be obtained with this recording geometry conveniently where all the beams are incident from the same half-space. These results will provide us with more understanding of this important recording geometry and give guidelines to its use in experiments.