Electron spin control in dilute nitride semiconductors

We report on a study of spin-dependent recombination processes (SDR) for conduction band electrons on deep paramagnetic centers in a series of GaAs(1-y)N(y) epilayers by time-resolved optical orientation experiments. We demonstrate that this dilute nitride compound can be used as an effective electron spin filter under a polarized optical excitation of appropriate intensity. This optimum intensity can moreover be controlled by adjusting the nitrogen composition in the layer.

Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

Generating, manipulating and detecting electron spin polarization and coherence at room temperature is at the heart of future spintronics and spin-based quantum information technology. Spin filtering, which is a key issue for spintronic applications, has been demonstrated by using ferromagnetic metals, diluted magnetic semiconductors, quantum point contacts, quantum dots, carbon nanotubes, multiferroics and so on. This filtering effect was so far restricted to a limited efficiency and primarily at low temperatures or under a magnetic field. Here, we provide direct and unambiguous experimental proof that an electron-spin-polarized defect, such as a Ga(i) self-interstitial in dilute nitride GaNAs, can effectively deplete conduction electrons with an opposite spin orientation and can thus turn the non-magnetic semiconductor into an efficient spin filter operating at room temperature and zero magnetic field. This work shows the potential of such defect-engineered, switchable spin filters as an attractive alternative to generate, amplify and detect electron spin polarization at room temperature without a magnetic material or external magnetic fields.

The relationship between changes in self-rated quality of life after cochlear implantation and changes in individual complaints

OBJECTIVES

To evaluate the changes in self-rated quality of life (QoL) obtained following cochlear implantation in relation to changes in the individual's complaints.

DESIGN

We have used repeated responses over a period of at least 4 years following implantation so as to examine within-subject relationships.

PARTICIPANTS

Twenty-four consecutive post-lingually deafened patients who had been fitted with cochlear implants between 1991 and December 2000 at the University Hospital of Wales were investigated.

MAIN OUTCOME MEASURES

The open-ended problems questionnaire was used to assess what hearing impaired people themselves considered to be the main problems arising from their hearing loss. The participants were asked to rate the severity of each one of these problems as well as QoL on '0' to '100' visual analogue scales. Both the individual problem ratings and the ratings of QoL were re-administered to the subjects at each follow-up session.

RESULTS

Changes in the rated QoL of all patients were significantly associated with changes in specific complaints, for example, the ability to communicate, feeling of isolation, telephone use, self-confidence, enjoyment of music and watching the TV. Multiple stepwise regression analysis showed that, after implantation, improvements in communication abilities, reduced psychological problems and improvements in abilities of daily life were the key determinants of QoL improvement for individual cochlear implant patients. These key predictors reached a plateau at about 1.5-3 years after cochlear implantation.

CONCLUSIONS

The relationships between changes in specific complaints and the QoL in individual implantees were highlighted. We suggest that cochlear implant outcome measures should continue for at least 3 years after implantation.

Predicting metabolizable energy of normal corn from its chemical composition in adult Pekin ducks

Two experiments were conducted to establish an ME content prediction model for normal corn for ducks based on the grain's chemical composition. In Experiment 1, observed linear relationships between the determined ME content of 30 corn calibration samples and proximate nutrients, acid detergent fiber (ADF), and neutral detergent fiber (NDF) were used to develop an ME prediction model. In Experiment 2, 6 samples of corn selected at random from the primary corn-growing regions of China were used for testing the accuracy of ME prediction models. The results indicated that the AME, AME(n), TME, and TME(n) were negatively correlated with crude fiber (r = -0.905), ADF (r = -0.915), and NDF (r = -0.95) contents, and moderately correlated with gross energy (GE; r = -0.55) content in corn calibration samples. In contrast, no significant correlations were found for CP, ether extract, and ash contents. According to the stepwise regression analysis, both NDF and GE were found to be useful for the ME prediction models. Because the maximum absolute difference between the in vivo ME determinations and the predicted ME values was 61 kcal/kg, it was concluded that, for White Pekin ducks, the latter could be used to predict the ME content of corn with acceptable accuracy.

Inhibition of metastasis to lung of a human nasopharyngeal carcinoma cell line CNE- 2L2 transfected with pRc/ CMV-antisense 6A8 cDNA in nude mice

The growth of CNE-2L2 cell, a cloned line of human nasopharyngeal carcinoma with a high potentiality of metastasis to lung was inhibited to a certain extent after transfection with a recombinant antisense expression vector of a cDNA encoding a human alpha-mannosidase (pRc/CMV-antisense 6A8 cDNA) (the Genbank accession number of 6A8 cDNA is U37248) in comparison with that of the cell transfected with the Mock and of the wild cell. Two months after a subcutaneous inoculation of CNE-2L2 cell into the axilla of nude mice metastatic lesions in the lung were observed in 9/10 mice (90%) with grade III in 8 mice and grade II in one mouse in the wild cell group, in 6/8 mice (75 %) with grade III in one mouse, grade II in 2 mice and grade I in 3 mice in the Mock-transfection group, in only 3/10 mice (30%) with all grade I in pRc/CMV-antisense 6A8 cDNA-transfection group.

Prevalence of and risk factors for isolated systolic hypertension in the rural adult population of Liaoning Province, China

The prevalence of and associated risk factors for isolated systolic hypertension, as defined by the Joint National Committee (JNC)-6 classification, were investigated in the rural population of Liaoning Province, China. A total of 45,925 people aged 35 years or older were examined in a cross-sectional study. Overall, the prevalence of isolated systolic hypertension was 10.6% (males 10.1%; females 11.2%). The prevalence of isolated systolic hypertension was positively correlated with age, gender, smoking status, alcohol intake, body mass index, salt intake and Mongolian race. This study showed that isolated systolic hypertension was very common in rural Chinese people and that many risk factors are linked with isolated systolic hypertension.

Osteogenic behavior of alginate encapsulated bone marrow stromal cells: an in vitro study

Sodium alginate is a useful polymer for the encapsulation and immobilization of a variety of cells in tissue engineering because it is biocompatible, biodegradable and easy to process into injectable microbeads. Despite these properties, little is known of the efficacy of calcium cross-linked alginate gel beads as a biodegradable scaffold for osteogenic cell proliferation and differentiation. In this study, we investigated the ability of rabbit derived bone marrow cells (BMCs) to proliferate and differentiate in alginate microbeads and compared them with BMCs cultured in poly-L-lysine (PLL) coated microbeads and on conventional 2D plastic surfaces. Results show that levels of proliferation and differentiation in microbeads and on tissue culture plastics were comparable. Cell proliferation in microbeads however diminished after fortification with a coating layer of PLL. Maximum cell numbers observed were, 3.32 x 10(5) +/- 1.72 x 103; 3.11 x 10(5) +/- 1.52 x 10(3) and 3.28 x 10(5) +/- 1.21 x 10(3 ) for the uncoated, PLL coated and plastic surface groups respectively. Alkaline phosphatase and protein expressions reflected the stage of cell differentiation. We conclude that calcium cross-linked alginate microbeads can act as a scaffold for BMC proliferation and osteogenic differentiation and has potential for use as 3D degradable scaffold.

Effects of DNAzymes targeting Aurora kinase A on the growth of human prostate cancer

Aurora kinase A has been demonstrated to be involved in the malignant progression of many types of cancer including prostate cancer, we therefore hypothesized that Aurora kinase A might work as a valuable target for prostate cancer treatment. To test this hypothesis, we used DNAzyme technology to inhibit Aurora kinase A expression and evaluated the effects of DNAzymes as therapeutic agents to treat prostate cancer. In an in vitro cleavage assay, we found that a DNAzyme (DZ2) targeting Aurora kinase A could effectively cleave Aurora kinase A mRNA. When transfected into the prostate cancer cell line PC3, DZ2 was found to strongly inhibit the expression of Aurora kinase A examined by western blot analysis, and thus suppressed cell growth, arrested the progression of cell cycle, induced cell apoptosis and attenuated cell migration, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay, flow cytometry and Boyden chamber assay. Through in vivo study, we also found that DZ2 could significantly inhibit the growth of human prostate cancer xenografts in nude mice. In conclusion, DZ2 could effectively attenuate malignant progression of prostate cancer both in vitro and in vivo, suggesting that DNAzyme targeting Aurora kinase A may be used as a valuable therapy to treat prostate cancer.

Strain field measurements on mouse carotid arteries using microscopic three-dimensional digital image correlation

A stereomicroscope system is adapted to make accurate, quantitative displacement, and strain field measurements with microscale spatial resolution and nanoscale displacement resolution on mouse carotid arteries. To perform accurate and reliable calibration for these systems, a two-step calibration process is proposed and demonstrated using a modification to recently published procedures. Experimental results demonstrate that the microscope system with three-dimensional digital image correlation (3D-DIC) successfully measures the full 3D displacement and surface strain fields at the microscale during pressure cycling of 0.40-mm-diameter mouse arteries, confirming that the technique can be used to quantify changes in local biomechanical response which may result from variations in extracellular matrix composition, with the goal of quantifying properties of the vessel.

Prevalence of metabolic syndrome in Han and Mongolian rural population with hypertension

The prevalence of metabolic syndrome, as defined by the International Diabetes Federation, was compared in two rural populations with hypertension in China. A total of 6326 subjects aged >or= 35 years were included: 5043 Han and 1283 Mongolian. Metabolic syndrome was identified in 33.9% (men: 16.1%; women: 47.8%) of the Han and 37.6% (men: 14.7%; women: 55.0%) of the Mongolian populations. In men, prevalence of metabolic syndrome showed no obvious ethnicity differences; however, in women, prevalence was significantly higher in the Mongolian than in the Han population. This study showed high prevalence and ethnic differences in prevalence of metabolic syndrome in these two Chinese hypertensive populations.

Effects of dietary metabolizable energy and crude protein content on the activities of digestive enzymes in jejunal fluid of Peking ducks

The response of digestive enzymes activities in the jejunal fluid of Peking ducks to dietary ME and CP content was investigated. In experiment 1, jejunal digesta from 24 cannulated male white Peking ducks of 18 wk of age were collected for 1 h out of every 4 h beginning at 0930 h on d 16, 18, and 20 of the experiment. The activities of amylase, trypsin, and chymotrypsin in jejunal fluid were determined. In experiment 2, 72 male cannulated ducks were randomly sorted into 4 groups. Four treatments consisted of combinations of 3,050 and 2,800 kcal/kg of ME, and 17.50 and 14.40% CP content were available ad libitum. Jejunal digesta samples were collected for 1 h every 4 h from 0930 to 1830 h on d 31, 33, and 35 of the experiment according to the results of experiment 1. The activities of amylase, trypsin, chymotrypsin, lipase, sucrase, and maltase in jejunal fluid were determined. In experiment 1, significant differences were found in the average activities of amylase and chymotrypsin among days. The collection time significantly affected the 3 enzyme activities, and average enzyme activities during the day were higher and more stable than during the night. In experiment 2, the effect of dietary ME content on the 6 digestive enzymes activities was not significant. But the dietary protein content significantly changed amylase, trypsin, and chymotrypsin activities.

TRED: a transcriptional regulatory element database, new entries and other development

Transcriptional factors (TFs) and many of their target genes are involved in gene regulation at the level of transcription. To decipher gene regulatory networks (GRNs) we require a comprehensive and accurate knowledge of transcriptional regulatory elements. TRED (http://rulai.cshl.edu/TRED) was designed as a resource for gene regulation and function studies. It collects mammalian cis- and trans-regulatory elements together with experimental evidence. All the regulatory elements were mapped on to the assembled genomes. In this new release, we included a total of 36 TF families involved in cancer. Accordingly, the number of target promoters and genes for TF families has increased dramatically. There are 11,660 target genes (7479 in human, 2691 in mouse and 1490 in rat) and 14,908 target promoters (10,225 in human, 2985 in mouse and 1698 in rat). Additionally, we constructed GRNs for each TF family by connecting the TF-target gene pairs. Such interaction data between TFs and their target genes will assist detailed functional studies and help to obtain a panoramic view of the GRNs for cancer research.

Glucose levels predict hospitalization for congestive heart failure in patients at high cardiovascular risk

BACKGROUND

Patients with diabetes mellitus (DM) are at high risk of developing congestive heart failure (CHF). However, the relationships between glucose levels and CHF in people with or without a history of DM have not been well characterized.

METHODS AND RESULTS

We evaluated the associations between fasting plasma glucose and risk of hospitalization for CHF during follow-up in patients at high cardiovascular risk and without CHF enrolled in a large-scale clinical trials program. Baseline fasting plasma glucose levels were assessed in 31,546 high-risk subjects with > or = 1 coronary, peripheral, or cerebrovascular disease or DM with end-organ damage who are participating in 2 ongoing parallel trials evaluating the effects of telmisartan, ramipril, or their combination (Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial [ONTARGET]; n=25,620) and the effects of telmisartan against placebo in angiotensin-converting enzyme-intolerant patients (Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease [TRANSCEND]; n=5926). Interim analyses blinded for randomized treatment were performed to compare baseline fasting plasma glucose with the adjusted CHF event rate at a mean follow-up of 886 days. Multivariable Cox regression models were performed, and associations were reported as hazard ratios and 95% confidence intervals. Among all subjects (mean age, 67 years; 69% men), of whom 11,708 (37%) had known DM and 1006 (3.2%) had newly diagnosed DM at baseline, 668 patients were hospitalized for CHF during follow-up. After adjustment for age and sex, a 1-mmol/L-higher fasting plasma glucose was associated with a 1.10-fold-increased risk of CHF hospitalization (95% confidence interval, 1.08 to 1.12; P<0.0001). The association persisted after adjustment for age, sex, smoking, previous myocardial infarction, hypertension, waist-to-hip ratio, creatinine, DM, and use of aspirin, beta-blockers, or statins (hazard ratio, 1.05; 95% confidence interval, 1.02 to 1.08; P<0.001).

CONCLUSIONS

Fasting plasma glucose is an independent predictor of hospitalization for CHF in high-risk subjects. These data provide theoretical support for potential direct beneficial effects of glucose lowering in reducing the risk of CHF and suggests the need for specific studies targeted at this issue.