Role of AAO template filling process parameters in controlling the structure of one-dimensional polymer nanoparticles

Solution template wetting is a common technique used to fabricate elongated polymer nanostructures; however, the parameters controlling the resulting morphology remain unclear. The purpose of this investigation was to elucidate the effects of process variables on the types of nanostructures obtained and to understand the physical mechanisms associated with structure development. 1 wt% polystyrene-THF solutions were infiltrated into commercial and homemade anodized aluminum oxide (AAO) templates. The wetting interaction between the AAO template and the polymer solution was examined through contact angle measurements. In general, for moderate dipping times (<18 h), the morphology of the nanopolymer was rod-like at low molecular weights, while tubes were observed at high molecular weight, even at this low concentration. Nanorods were obtained for all molecular weights for extended dipping times. The data suggest that phase separated layers may grow sequentially from the pore walls and yield nanotubes if the growth is interrupted or produce nanorods for unhindered deposition over long periods.

A Rac1/PAK1 cascade controls β-catenin activation in colon cancer cells

P21-activated kinase 1 (PAK1) is associated with colon cancer progression and metastasis, whereas the molecular mechanism remains elusive. Here, we show that downregulation of PAK1 in colon cancer cells reduces total β-catenin level, as well as cell proliferation. Mechanistically, PAK1 directly phosphorylates β-catenin proteins at Ser675 site and this leads to more stable and transcriptional active β-catenin. Corroborating these results, PAK1 is required for full Wnt signaling, and superactivation of β-catenin is achieved by simultaneous knockdown of adenomatous polyposis coli protein and activation of PAK1. Moreover, we show that Rac1 functions upstream of PAK1 in colon cancer cells and contributes to β-catenin phosphorylation and accumulation. We conclude that a Rac1/PAK1 cascade controls β-catenin S675 phosphorylation and full activation in colon cancer cells. Supporting this conclusion, overexpression of PAK1 is observed in 70% of colon cancer samples and is correlated with massive β-catenin accumulation.

Pharmacokinetics of antofloxacin hydrochloride in healthy male subjects after multiple intravenous dose administration

The purpose of the study was to evaluate pharmacokinetic characteristics of antofloxacin hydrochloride, a new fluoroquinolone antibiotic, during a multiple, intravenous dosing regimen. Twelve healthy, Chinese male volunteer subjects were each given 300 mg of antofloxacin by intravenous infusion once daily for 7 days. Blood and urine samples were taken at designated time points for analysis of antofloxacin concentration by high-performance liquid chromatography (HPLC). Safety and tolerability were assessed by evaluation of subject complaints, vital signs, electrocardiograms, electroencephalograms, clinical chemistry parameters, haematology and urinalysis and prothrombin time. The serum steady concentration of antofloxacin was obtained in 96 h after the administration of a daily intravenous dose of 300 mg of the drug. In the present study, the following pharmacokinetic parameters after 7 days of treatment with antofloxacin were determined to be: C(max) 3.81 ± 0.66 mg/L, C(min) 0.85 ± 0.19 mg/L, AUC(0-24) 60.51 ± 8.30 mg/L·h, C(av) 2.52 ± 0.35 mg/L, PTF 87.45 ± 3.37%, t(1/2)β 20.34 ± 1.88 h. The C(max) and AUC(0-24) after 7-day treatment were both higher than after the first dose (by 43% and 110%, respectively). The cumulative urinary elimination of antofloxacin within 96 h after the last dose was about 56%. During the study, there were neither subject complaints nor significant adverse clinical findings. Antofloxacin, administered intravenously as a single, daily 300 mg dose for 7 days, demonstrated favourable pharmacokinetic characteristics and tolerability. The results of this study indicate that antofloxacin hydrochloride is suitable for further clinical study.

Body fat distribution and their associations with cardiovascular risk, insulin resistance and β-cell function: are there differences between men and women?

OBJECTIVE

The objective was to examine the independent and gender-specific effects of WC and BMI on CVD risk factors, insulin resistance and β-cell function.

DESIGN

A cross-sectional study of 2931 adults aged 20-79 years was carried out in Fujian province by multi-stratified sampling from July 2007 to May 2008. Gender-specific differences of WC and BMI on CVD risk factors, insulin resistance and β-cell function were displayed jointly by WC and BMI tertiles. The homeostasis model assessment of insulin resistance (HOMA-IR) index and the quantitative insulin-sensitivity check index (QUICKI): l/(log G0 ± log I0) were used to estimate insulin sensitivity; insulin secretion was assessed using the HOMA-β index; β-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 min during the OGTT (△I30/△G30). The oral disposition index (DIo) was calculated as ΔI(30) /ΔG(30) × 1/fasting insulin. The Matsuda index is defined as 10,000/sqrt (FBG × FPI × [G × I]) where FPG is fasting glucose, FPI is fasting insulin, G is mean glucose during the OGTT (calculated from glucose samples at 0, 30, and 120 min), and I is mean insulin during the OGTT (calculated from insulin samples at 0, 30, and 120 min).

RESULTS

Waist circumference and BMI correlated with each other in both men (0.756, p < 0.001) and women (0.728, p < 0.001). The two indexes were independently associated with CVD risk factors (such as hypertension, metabolic syndrome, and dyslipidaemia) in both men and women. BMI was better than WC in assessing the risk of diabetes in men (p = 0.003 for BMI, and p = 0.234 for WC), while WC was better than BMI in predicting diabetes in women (p < 0.001 for WC, and p = 0.831 for BMI). There were significant associations between BMI and insulin resistance or β-cell function even after adjustment for WC except for DIo in male subjects, but WC only associated with HOMA-IR positively or the Matsuda index and QUICKI negatively after adjustment for BMI. For women, associations between WC and insulin resistance or β-cell function remained strong even after adjustment for BMI besides DIo. However, there were no independent relations of BMI to insulin resistance and β-cell function except for Matsuda index with a significant negative association after adjustment for WC in women.

CONCLUSION

Body mass index and WC were independently associated with CVD risk factors. There were differences in the gender-specific relevance of measures of body fat distribution in assessing the insulin resistance, β-cell function and thus the risk of diabetes. Therefore, WC should be measured in addition to BMI to assess CVD risk accurately and implement efficient treatment strategies.

The correlation between the oral glucose tolerance test 30-minutes plasma glucose and risk factors for diabetes and cardiovascular diseases: a cross-sectional epidemiological study of diabetes in Fujian Province in the South-East of China

OBJECTIVE

To investigate the correlation between abnormal oral glucose tolerance test (OGTT) 30-min plasma glucose (PG) and risk factors and metabolic abnormalities of diabetes and cardiovascular diseases (CVD).

METHODS

Participants (no.=2457) underwent a physical examination, blood biochemistry examination, OGTT, and a 12-lead electrocardiogram. We measured fasting PG (FPG) and PG at 30 min (30minPG) and 1 h (1hPG) of the OGTT. The association between an increase in 30minPG (by 1 SD) and the metabolic abnormalities of diabetes and CVD such as hypertension, overweight and obesity, central obesity, and hyperlipidemia; osteoporosis was assessed by logistic regression analysis after controlling for FPG and 2hPG.

RESULTS

This analysis showed that an increase of 30minPG by 1 SD (1.92 mmol/l) significantly increased the risk of chronic metabolic abnormalities in diabetes and CVD such as hypertension, overweight, and obesity, central obesity, hyperlipidemia, and osteoporosis. Stepwise multiple regression analysis also showed that 30minPG was significantly correlated with male gender, smoking, FPG, 2hPG, total cholesterol, waist/hip ratio, and blood pressure.

CONCLUSIONS

An elevation of 30minPG increased the risk of diabetes and CVD. The increased risk was independent of FPG, 2hPG, age, sex, and smoking status.

Relaxation of a Strained Elastic Film on a Viscous Layer

Experiments were conducted with SiGe film islands on a layer of borophosphorosilicate glass (BPSG). Initially the SiGe is under compression. Upon annealing, the glass flows and the SiGe islands relax by both inplane expansion and wrinkling. This paper provides a two-dimensional (2D) model for inplane expansion. The results from the model are compared with the experiments with small SiGe islands. The effect of winkling, which is ignored in the present model, is discussed qualitatively.

Creep Study for Fatigue Life Assessment of Two Lead-Free High Temperature Solder Alloys

Creep of two lead-free high temperature solder alloys, 95Sn-5Ag and 99Sn-1.0Cu was studied in this investigation. Room and high temperature creep tests were performed to examine deformation mechanisms and to establish mathematical models of creep deformation for the alloys. A state variable creep model was introduced to model both primary and secondary creep deformation of these two alloys which show a very significant primary creep. Fatigue life models of the alloys were established based on an energy-based failure criteria, which was deduced from variable strain amplitude tests at a constant strain rate of 0.003/sec, and from variable strain rates tests with two constant strain amplitudes of 0.005 and 0.01. Applications of the creep model includes determination of peak loads and hysteresis strain energy density in strain-controlled fatigue tests. It is demonstrated that the creep model can be very helpful to establish fatigue failure criteria and to assess fatigue lives of these two alloys.