Plasmon Tuning of Liquid Gallium Nanoparticles through Surface Anodization.

In this work, tunable plasmonic liquid gallium nanoparticles (Ga NPs) were prepared through surface anodizing of the particles. Shape deformation of the Ga NPs accompanied with dimpled surface topographies could be induced during electrochemical anodization, and the formation of the anodic oxide shell helps maintain the resulting change in the particle shape. The nanoscale dimple-like textures led to changes in the localized surface plasmon resonance (LSPR) wavelength. A maximal LSPR red-shift of ~77 nm was preliminarily achieved using an anodization voltage of 0.7 V. The experimental results showed that an increase in the oxide shell thickness yielded a negligible difference in the observed LSPR, and finite-difference time-domain (FDTD) simulations also suggested that the LSPR tunability was primarily determined by the shape of the deformed particles. The extent of particle deformation could be adjusted in a very short period of anodization time (~7 s), which offers an efficient way to tune the LSPR response of Ga NPs.

Student Stress and Online Shopping Addiction Tendency among College Students in Guangdong Province, China: The Mediating Effect of the Social Support.

Online shopping addiction tendency (OSAT) among college students has become too serious to ignore. As a result, it is necessary to carefully examine the relevant factors that shape students' online shopping addiction tendencies. This study aimed to determine whether social support mediates the relationship between college students' stress (academic hassle, personal hassle, and negative life events) and OSAT. In this cross-sectional study using a convenient sampling method, Chinese students from eight universities in Guangdong Province, China, completed self-administered questionnaires in either printed or online format. The survey data includes daily online shopping usage, college student stress, a social support rating scale, an online shopping addiction tendency scale for college students, and demographic information. A total number of verified and valid questionnaires were returned. In a sample of 1123 (mean age = 20.28 years; 58% females). Each individual had online shopping experience. The survey revealed no gender differences in OSAT. There was a statistically significant relationship between student stress (academic hassle, personal hassle, and negative life events) and students' OSAT scores and social support. The latter was negatively correlated with OSAT and mediated the relationship between college students' stress and their OSAT. In conclusion, university students' stress (academic hassle, personal hassle, and negative life events) acts as a trigger for OSAT. A combination of a high stress level and a lack of social support increases the likelihood of developing OSAT. Social support has an effect on the OSAT of college students by relieving their stress; social support is a protective factor against the OSAT for college students.

Arenobufagin activates p53 to trigger esophageal squamous cell carcinoma cell apoptosis in vitro and in vivo.

Esophageal squamous cell carcinoma (ESCC) is often diagnosed at late incurable stage and lacks effective treatment strategy. Bufadienolides are cardiotonic steroids isolated from the skin and parotid venom glands of the toad Bufo bufo gargarizans Cantor with novel anticancer activity. However, there is little information about the effects and action mechanisms of bufadienolides on ESCC cells. In this study, the in vitro and in vivo anti-ESCC activities of bufadienolides, including bufalin (Bu) and arenobufagin (ArBu), were examined and the underlying molecular mechanisms were elucidated. The results showed that ArBu exhibited higher anticancer efficacy than Bu against a panel of five ESCC cells, with IC50 values ranging from 0.8 µM to 3.6 µM. However, ArBu showed lower toxicity toward Het-1A human normal esophageal squamous cells, indicating its great selectivity between cancer and normal cells. Moreover, ArBu effectively induced ESCC cell apoptosis mainly by triggering caspase activation through intrinsic and extrinsic pathways. Treatment of ESCC cells also significantly activated p53 signaling by enhancing its phosphorylation. Interestingly, transfection of cells with p53 small interfering RNA significantly inhibited the ArBu-induced p53 phosphorylation and the overall apoptotic cell death. Furthermore, ArBu also demonstrated novel in vivo anticancer efficacy by inhibiting the tumor growth through activation of p53 pathway. Taken together, these results demonstrate the p53-targeting therapeutic potential of bufadienolides against ESCC.

[Clinical characteristics of and factors related to relapse in chronic hepatitis B patients after nucleoside analogues withdrawal].

OBJECTIVE: To investigate the clinical characteristics of and factors related to relapse in chronic hepatitis B (CHB) patients who had previously achieved cessation criteria and had been withdrawn from nucleoside analogues treatment. METHODS: Sixty CHB patients who experienced relapse after nucleoside analogues withdrawal based on cessation criteria were enrolled in the study retrospectively. Each patient's data on biochemical, serological and viral characteristics corresponding to baseline (treatment initiation), withdrawal and relapse were collected. COX proportional hazard modeling was used to evaluate the factors related to relapse. RESULTS: The hepatitis B e antigen (HBeAg)-positive and -negative patients had similar median antiviral treatment times (38 months (range: 24 - 80) vs. 35 months (30 - 60); Z = -1.313, P more than 0.05). For all patients, the median follow-up time was 12 months (2 - 72), during which 49 (81.7%) patients developed virological breakthrough and 17 (28.3%) developed HBeAg recurrence. The patients who experienced virological breakthrough or HBeAg recurrence had significantly higher baseline levels of HBV DNA than those patients who remained disease-free (t = 2.15 and -2.54 respectively; P less than 0.05). The median relapse time of the HBeAg-positive patients was significantly longer than that of the HBeAg-negative patients (14 months (3 - 72) vs. 6 months (3 - 36); Chi-square test = 7.045, P less than 0.01). HBeAg status at baseline was identified as an independent factor associated with relapse (relative risk = 1.937, 95% confidence interval = 1.14-3.28, P less than 0.05). CONCLUSION: HBeAg-positive and-negative patients showed distinct clinical characteristics of relapse, with the latter being more prone to relapse soon after nucleoside analogues withdrawal. Prolonging the treatment course may be beneficial to HBeAg-negative patients, even if cessation criteria are achieved.

[The impact of early rapid virological response on the outcomes of hepatitis B associated acute on chronic liver failure during antiviral treatment].

OBJECTIVE: To investigate the impact of early rapid virological response on the outcomes of hepatitis B associated acute on chronic liver failure during antiviral treatment. METHODS: 106 acute on chronic liver failure patients in our hospital from January 2008 to July 2010 were enrolled in present study retrospectively. Besides internal medicine therapy, all patients received lamivudine (100 mg/d) or entecavir (0.5 mg/d) treatment. The profile of liver biochemistry, prothrombin time activity and viral load were detected at baseline and week 4, respectively. The patients were divided into HBV DNA negative group and HBV DNA positive group according to the viral load at week 4. The clinical features and treatment outcomes were compared between groups. Frequency variables were compared by x2 test or Fisher's exact test. Continuous variables were compared using independent samples T-test. The factors that impact on the treatment outcomes were determined using stepwise multivariate logistic regression analysis. RESULTS: At the week 4, the TBil and PTA in HBV DNA positive group [(261.6+/-205.6)mumol/L and 44.7%+/-19.7%, respectively] were significantly different from those in HBV DNA negative group [(160.1+/-173.4) mumol/L and 56.8%+/-23.1%, respectively] ( t = 2.190 and -2.077, respectively, P less than 0.05). The non-effective rate of HBVDNA positive group (50%, 9/18) was significantly higher than that of HBV DNA negative group (14.8%, 13/88) (x2 = 9.235, P less than 0.01). By using stepwise multivariate logistic regression analysis, the disease stage and HBV DNA undetectable at week 4 were the independent factor. The OR values of disease stage and HBV DNA undetectable were 6.559 and 0.209, respectively, and 95% CI was 2.316~18.576 and 0.058~0.747, respectively. CONCLUSION: The rapid suppression of viral load by nucleotide analogue may improve the efficacy of hepatitis B associated acute on chronic liver failure treatment. The early rapid virological response within first 4 weeks may contribute to the prediction of the treatment outcomes.

Molecular-scale soft imprint lithography for alignment layers in liquid crystal devices.

We describe molecular-scale soft nanoimprint lithographic replication of rubbed polyimide substrates to form alignment layers for liquid crystal devices. Systematic studies of the surface relief morphology of the polyimide and molded structures in three different polymers illustrate good lithographic fidelity down to relief heights of several nanometers, and with some capabilities at the level of approximately 1 nm. Collective results of experiments with several polymer formulations for molds and molded materials and process conditions indicate that this molecular-scale fidelity in replication can be used to produce surfaces that will effectively align liquid crystal molecules. Good electro-optical responses from liquid crystal light modulators that are formed in this manner suggest utility for fundamental studies and potential practical application.

Soft lithography using acryloxy perfluoropolyether composite stamps.

This paper describes composite patterning elements that use a commercially available acryloxy perfluoropolyether (a-PFPE) in various soft lithographic techniques, including microcontact printing, nanotransfer printing, phase-shift optical lithography, proximity field nanopatterning, molecular scale soft nanoimprinting, and solvent assisted micromolding. The a-PFPE material, which is similar to a methacryloxy PFPE (PFPE-DMA) reported recently, offers a combination of high modulus (10.5 MPa), low surface energy (18.5 mNm(-1)), chemical inertness, and resistance to solvent induced swelling that make it useful for producing high fidelity patterns with these soft lithographic methods. The results are comparable to, and in some cases even better than, those obtained with the more widely explored material, high modulus poly(dimethylsiloxane) (h-PDMS).

Addressable electric fields for size-fractioned sample extraction in microfluidic devices.

Fraction collection following electrophoresis is of major importance for a variety of biological analyses. These assays typically need to identify specific fractions in the separated sample for further processing and require extraction of one or a group of fragments. In this paper, we have developed and characterized a technique to generate addressable electric fields for improved extraction during electrophoresis in microfluidic devices. The addressable electric field is achieved by applying a low bias voltage (1-2 V) to microelectrode pairs within the electrophoresis microchannel. Theoretical analysis shows the purity of the extracted sample can be improved as much as 30% over extraction without the shaped electric fields, and nearly 100% predicted yield can be achieved. We also describe the theoretical design of shaped electric fields by characterizing the optimal electrode geometry, field strength, channel configuration, and electrophoretic migration behavior needed for efficient band extraction.

Selective extraction of size-fractioned DNA samples in microfabricated electrophoresis devices.

We have designed and constructed a microfabricated device for separation of double-stranded DNA fragments using a crosslinked sieving medium and spatially selective extraction of the desired fraction. Based on measuring the width and spacing of migrating bands, a narrow side channel is constructed perpendicular to the separation channel to collect the DNA fragments of interest. This selective collection technique was tested using a 100 base pair double-stranded DNA ladder. We successfully demonstrate selective extraction of the desired fragment with minimal interference from the adjacent bands in an electric field of 31 V/cm. We also achieve extraction of multiple DNA fragments using an array of microelectrodes in this side channel. The device uses cross-linked polyacrylamide gel matrix, allowing the separation to be performed in a distance of 1 cm or less and at a low electric field strength. Together with on-chip electrode, this design is amenable to integration with reaction chambers into a single device for portable genetic-based analysis.

A versatile microfabricated platform for electrophoresis of double- and single-stranded DNA.

We demonstrate a versatile microfabricated electrophoresis platform, incorporating arrays of integrated on-chip electrodes, heaters, and temperature sensors. This design allows a range of different sieving gels to be used within the same device to perform separations involving both single- and double-stranded DNA over distances on the order of 1 cm. We use this device to compare linear and cross-linked polyacrylamide, agarose, and thermo-reversible Pluronic-F127 gels on the basis of gel casting ease, reusability, and overall separation performance using a 100 base pair double-stranded DNA ladder as a standard sample. While cross-linked polyacrylamide matrices provide consistently high-quality separations in our system over a wide range of DNA fragment sizes, Pluronic gels also offer compelling advantages in terms of the ability to remove and reload the gel. Agarose gels offer good separation performance, however, additional care must be exercised to ensure consistent gel properties as a consequence of the need for elevated gel loading temperatures. We also demonstrate the use of denaturing cross-linked polyacrylamide gels at concentrations up to 19% to separate single-stranded DNA fragments ranging in size from 18 to 400 bases in length. Primers differing by 4 bases at a read length of 30 bases can be separated with a resolution of 0.9-1.0 in under 20 min. This level of performance is sufficient to conduct a variety of genotyping assays including the rapid detection of single nucleotide polymorphisms (SNPs) in a microfabricated platform. The ability to use a single microelectrophoresis system to satisfy a wide range of separation applications offers molecular biologists an unprecedented level of flexibility in a portable and inexpensive format.