Metallic liquids and glasses: atomic order and global packing

In this Letter, we have revealed the common structural behavior of metallic glasses through scrutinizing the evolution of pair distribution functions from metallic liquids to glasses and statistically analyzing pair distribution functions of 64 metallic glasses. It is found that the complex atomic configuration in metallic glasses can be interpreted globally as a combination of the spherical-periodic order and local translational symmetry. The implications of our study suggest that the glass transition could be visualized mainly as a process involving in local translational symmetry increased from the liquid to glassy states.

Prevalence of erectile dysfunction among Chinese men with type 2 diabetes mellitus

The aims of this study were to investigate the prevalence of ED in Chinese men with type 2 diabetes mellitus, and evaluate the efficacy and safety of sildenafil citrate in these patients. Patients from 42 outpatient diabetes clinics with type 2 diabetes mellitus and ED as defined by the International Index of Erectile Function (IIEF)-5 were studied. Participants with ED received three doses (100 mg each) of sildenafil citrate for use over 3 months. Efficacy of sildenafil citrate was assessed using the IIEF-5 and the Global Efficacy Questionnaire (GEQ). Adverse events were recorded by patients in a daily diary. A total of 5477 participants were evaluated, and 75.2% had ED. Age, duration of diabetes and glycosylated hemoglobin (HbA(1)c) >6.5% were independently and significantly associated with the presence and degree of ED. Patients who received pharmacotherapy (N=389) reported significant improvements. The rate of erections as determined by the GEQ was also significantly improved following treatment. ED is a common complication in Chinese men with type 2 diabetes mellitus, and certain risk factors are associated with the presence of ED and severity. Sildenafil citrate is a safe and effective treatment for these patients.

A common variant of NOS1AP is associated with QT interval duration in a Chinese population with Type 2 diabetes

AIMS

Electrocardiographic ventricular repolarization QT parameters are independent risk factors for cardiovascular events and sudden cardiac death in diabetic patients. The aim of the study was to investigate the association of polymorphisms of the nitric oxide synthase 1 adaptor protein (NOS1AP) gene with QT interval in Chinese subjects with or without Type 2 diabetes.

METHODS

Three single nucleotide polymorphisms (SNPs) (rs10494366, rs12143842 and rs12029454) were genotyped in 1240 Type 2 diabetic patients (631 men and 609 women) and 1196 normal controls (433 men and 763 women). Individuals with overt diseases other than diabetes were excluded. Heart-rate corrected QT interval (QTc) was determined by standard 12-lead ECG and Bazett formula. Sex-pooled analysis and sex-specific analysis for genotype-phenotype association were both conducted.

RESULTS

In the diabetic group, the rs12143842 T allele was associated with a 3.87-ms (P = 0.014, empirical P = 0.039) increase in QTc duration for each additional allele copy, while rs10494366 and rs12029454 exhibited no significant association with QTc. We found no evidence of association for the three SNPs in subjects with normal glucose regulation. No significant SNP-gender and -diabetes affection interaction was observed.

CONCLUSIONS

The genetic variant rs12143842 in NOS1AP is associated with QT interval duration in a Chinese population with Type 2 diabetes. Future studies in different populations are needed to validate this finding and to evaluate the impact of NOS1AP variants on cardiovascular events and sudden cardiac death in diabetic patients.

Atomistic free-volume zones and inelastic deformation of metallic glasses

The amorphous nature of metallic glasses and their mechanical properties make them interesting for structural applications. However, the interplay between the nature of atomic structures in metallic glasses and mechanical properties remains poorly understood. In this study, high-frequency dynamic micropillar tests have been used to probe both atomic clusters and flow defects in metallic glasses. We show that loosely bonded atomistic free-volume zones that are enveloped elastically by tightly bonded atomic clusters show a deformation character similar to supercooled liquids. At room temperature, the effective viscosity of these free-volume zones is of the order of 1 x 10(8) Pa s before the occurrence of shear banding. The confined liquid-like deformation of free-volume zones leads to significant mechanical hysteresis in micropillars under dynamic loading, providing important insight into how atomistic structural features affect the deformation behaviours in metallic glasses in the apparent elastic regime. The inelastic behaviour also serves as the basis for the superior damping resistance of metallic glasses.

Characterization of nestin expression in the spinal cord of GFP transgenic mice after peripheral nerve injury

Many studies have shown that activation and increase in the number of astrocytes and microglia in the spinal cord participate in the initiation and maintenance of neuropathic pain, but little attention has been paid to the responses of neural progenitor cells to peripheral nerve injury. Nestin, a class VI intermediate filament protein, is expressed both in neuronal and glial progenitors as well as in their common precursors; and nestin-positive cells appear in the brain and spinal cord following various forms of damage to these regions. To clarify the responses of neural progenitor cells to nerve injury, we applied L5 spinal nerve transection (L5-SNT) to nestin-promoter GFP (pNestin-GFP) transgenic mice to narrow the target to them. While pNestin-GFP expression was strongly retained in the ependyma lining the central canal of the transgenic spinal cord even in adulthood, it was markedly reduced in the dorsal horn during postnatal development by day 7. Increases in pNestin-GFP expression and labeling by the proliferation marker 5-bromodeoxyuridine were broadly found in the dorsal horn of adult mice on day 3 after L5-SNT. On the other hand, the activation and increase in number of microglia and astrocytes are restricted to the superficial layer of the dorsal horn, the central terminal of injured primary afferent fibers. Purinergic P2X agonist α, β-MeATP increased [Ca(2+)]i in nestin-positive cells in the superficial layer ipsilateral to nerve injury and P2 receptor antagonists suramin and pyridoxalphosphate-6-azophenyl-2,4-disulphonic acid (PPADS) blocked the expression and elongation of pNestin-GFP fibers in the slice culture of the spinal cord. These results with pNestin-GFP transgenic mice demonstrate that nestin-positive cells proliferate in the dorsal horn in response to peripheral nerve injury and suggest that ATP may contribute to the expression of nestin and activation of neural progenitor cells after nerve injury.

Using support vector regression coupled with the genetic algorithm for predicting acute toxicity to the fathead minnow

The potential toxicity of chemicals may present adverse effects to the environment and human health. The quantitative structure-activity relationship (QSAR) provides a useful method for hazard assessment. In this study, we constructed a QSAR model based on a highly heterogeneous data set of 571 compounds from the US Environmental Protection Agency, for predicting acute toxicity to the fathead minnow (Pimephales promelas). An approach coupling support vector regression (SVR) with the genetic algorithm (GA) was developed to build the model. The generated QSAR model showed excellent data fitting and prediction abilities: the squared correlation coefficients (r(2)) for the training set and the test set were 0.826 and 0.802, respectively. Only eight critical descriptors, most of which are closely related to the toxicity mechanism, were chosen by GA-SVR, making the derived model readily interpretable. In summary, the successful case reported here highlights that our GA-SVR approach can be used as a general machine learning method for toxicity prediction.

Requirement of the histone demethylase LSD1 in Snai1-mediated transcriptional repression during epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) has pivotal roles during embryonic development and carcinoma progression. Members of the Snai1 family of zinc finger transcription factors are central mediators of EMT and induce EMT in part by directly repressing epithelial markers such as E-cadherin, a gatekeeper of the epithelial phenotype and a suppressor of tumor invasion. However, the molecular mechanism underlying Snai1-mediated transcriptional repression remains incompletely understood. Here we show that Snai1 physically interacts with and recruits the histone demethylase LSD1 (KDM1A) to epithelial gene promoters. LSD1 removes dimethylation of lysine 4 on histone H3 (H3K4m2), a covalent histone modification associated with active chromatin. Importantly, LSD1 is essential for Snai1-mediated transcriptional repression and for maintenance of the silenced state of Snai1 target genes in invasive cancer cells. In the absence of LSD1, Snai1 fails to repress E-cadherin. In cancer cells in which E-cadherin is silenced, depletion of LSD1 results in partial de-repression of epithelial genes and elevated H3K4m2 levels at the E-cadherin promoter. These results underline the critical role of LSD1 in Snai1-dependent transcriptional repression of epithelial markers and suggest that the LSD1 complex could be a potential therapeutic target for prevention of EMT-associated tumor invasion.

Copper(II)-selective chelation improves function and antioxidant defences in cardiovascular tissues of rats as a model of diabetes: comparisons between triethylenetetramine and three less copper-selective transition-metal-targeted treatments

AIMS/HYPOTHESIS

Treatment with the Cu(II)-selective chelator triethylenetetramine (TETA) improves cardiovascular disease in human patients, and cardiac and vascular/renal disease in rats used as a model of diabetes. Here we tested two hypotheses: first, that TETA elicits greater improvement in organ function than less Cu-selective transition-metal-targeted treatments; second, that the therapeutic actions of TETA are consistent with mediation through suppression of oxidative stress.

METHODS

Rats were made diabetic with streptozotocin (55 mg/kg, i. v.) and treated from 8 weeks after disease induction for the following 8 weeks with effective dosages of oral TETA, or one of three less Cu-selective transition-metal-targeted treatments: D-penicillamine, deferiprone or Zn acetate. Treatment effects were measured in ex vivo cardiac and aortic tissues, plasma and urine.

RESULTS

Diabetes damaged both cardiac and renal/vascular function by impairing the ability of cardiac output to respond physiologically to rising afterload, and by significantly elevating the urinary albumin/creatinine ratio. Diabetes also lowered total antioxidant potential and heparan sulphate levels in cardiac and arterial tissues, and serum ferroxidase activity, whereas it elevated urinary heparan sulphate excretion. TETA treatment rectified or partially rectified all these defects, whereas the other three experimental treatments were ineffectual. By contrast, none of the four drug treatments lowered diabetes-mediated elevations of plasma glucose or lipid concentrations.

CONCLUSIONS/INTERPRETATION

TETA may limit the cardiac and renal/vascular damage inflicted by diabetes through its actions to reinforce antioxidant defence mechanisms, probably acting through selective chelation of 'loosely-bound'/chelatable Cu(II). It may also improve heparan sulphate homeostasis and bolster antioxidant defence by increasing vascular extracellular superoxide dismutase activity. Urinary albumin/creatinine ratio might prove useful for monitoring TETA treatment.

Improving emergency preparedness capability of rural public health personnel in China

OBJECTIVES

Since the outbreaks of severe acute respiratory syndrome and avian influenza, improving the emergency preparedness capability of rural public health personnel has become a new priority in building the infrastructure needed to address public health emergencies. The Chinese Government has carried out a series of emergency preparedness education and training programmes to improve the emergency preparedness capability of rural public health personnel nationwide. The purpose of this study was to evaluate and develop a participatory emergency preparedness training programme for rural public health personnel.

STUDY DESIGN

The research emphasizes the major components of instructional design, including assessing, designing, delivering and evaluating training. The approach is an integrated system with results from one phase influencing the next, so that a series of steps are followed when developing, implementing and evaluating emergency preparedness training.

METHODS

The 226 participants were rural public health personnel from 84 different rural centres for disease control and prevention in China. The programme was evaluated by anonymous questionnaires and semi-structured interviews held prior to training, immediately post-training and 12-months after training (follow-up).

RESULTS

The emergency preparedness training resulted in positive shifts in knowledge and skills for rural public health personnel. At follow-up, the knowledge and skill scores of participants declined slightly compared with the post-test levels (P>0.05). However, there was a significant increase compared with the pre-test levels (P<0.01). Moreover, more than 90% of participants reported that this training provided a valuable learning experience and reinforced the importance of emergency preparedness.

CONCLUSIONS

The emergency preparedness training programme was effective and feasible in improving the performance of rural public health personnel on emergency response. Further studies are needed to test the efficacy of the training approach for competency improvement.