A study of the density of states of ZnCoO:H from resistivity measurements

Understanding the electronic band structure and density of states (DOS) of a material and their relationship to the associated electronic transport properties is the starting point for optimizing the performance of a device and its technological applications. In a hydrogenated Zn_0.8Co_0.2O (ZnCoO:H) film with an inverted thin-film transistor structure, we found ambipolar behavior, which is shown in many field-effect devices based on graphene, graphene nanoribbons, and organic semiconductors. In this study, to obtain information on the DOS of ZnCoO:H to explain the ambipolar behavior in terms of the carrier density and type, resistivity and magnetoresistance measurements of a ZnCoO:H film were performed at 5 K. Our proposed DOS representation of ZnCoO:H explains qualitatively the experimental observations of carrier density modulation and ambipolar behavior. First-principles calculations of the DOS of ZnCoO:H were in good agreement with the proposed DOS representation. Through a comparison of first-principles calculations and experimental data, evidence for the existence of Co–H–Co in ZnCoO:H is suggested.

Ambipolar behavior in a hydrogenated Zn_0.8Co_0.2O (ZnCoO:H) film is investigated via resistivity and magnetoresistance measurements and first-principles calculations of the DOS. Evidence for the existence of Co–H–Co in ZnCoO:H is suggested.     

Medical Rehabilitation: Guidelines to Advance the Field With High-Impact Clinical Trials

The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.     

Mild renal insufficiency and risk of congestive heart failure in men and women > or =70 years of age

Mild renal insufficiency is increasingly recognized as an independent risk factor for cardiovascular disease. However, few data exist regarding its relation to risk of congestive heart failure (CHF), a major public health problem in the elderly. To determine if mild renal insufficiency is associated with risk of incident CHF in the elderly, we analyzed data from 3,618 participants in the prospective, community-based Established Populations for Epidemiologic Studies of the Elderly (EPESE), who had no known CHF and had serum creatinine levels measured from 1987 to 1989. Mean age of the study population was 78.3 +/- 5.4 years; 84% had creatinine values <1.5 mg/dl and 98% had creatinine values < or =2.0 mg/dl. Creatinine clearance (CrCl) was calculated using the Cockcroft-Gault equation. During 3.9 years of follow-up, 488 subjects developed incident CHF as defined by hospital discharge and death certificate data. In a multivariate proportional hazards model, CrCl was inversely associated with CHF risk (p value for trend <0.001). Those in the lowest quartile of CrCl (< or =36.9 ml/min) had a nearly twofold (hazards ratio [HR] 1.99, 95% confidence intervals [CI] 1.43 to 2.79) greater risk of incident CHF compared with those in the highest quartile (>57.4 ml/min). Renal insufficiency, defined as creatinine > or =1.5 mg/dl in men and > or =1.3 mg/dl in women, was also associated with increased CHF risk (multivariate HR 1.43, 95% CI 1.17 to 1.74). Thus, mild renal insufficiency was a strong independent predictor of CHF in this cohort, suggesting that serum creatinine may offer a readily accessible tool to identify elderly patients at risk for CHF.     

Low grade gastric mucosa associated lymphoid tissue lymphoma：Treatment strategies based on 10 year follow-up

AIM: To deduce strategic guidelines of gastric mucosa associated lymphoid tissue lymphoma (MALTOMA) by evaluating the long-term outcome of patients in respect to various treatment modalities. METHODS: A total of 55 patients with MALTOMA from May 1992 to August 2002 were retrospectively reviewed. RESULTS: Complete remission was obtained in 24 (82.8%) of 29 patients treated with anti Helicobacter pylori (H pylori) regimen only. The duration to reach complete remission was 12 months (85 percentile, 2-33 months). Five patients showed complete remission with radiation therapy (26-86 months). Two of them were H pylori treatment failure cases. CONCLUSION: H pylori eradication is an effective primary treatment option for low grade MALTOMA and radiation therapy could be considered in patients with no evidence of H pylori infection or who do not respond to H pylori eradication therapy 12 months after successful eradication.     

Coadministration of angiopoietin-1 and vascular endothelial growth factor enhances collateral vascularization

Using growth factors to induce vasculogenesis is a promising approach in the treatment of ischemic legs and myocardium. Because the vasculogenesis requires a cascade of growth factors, their receptors, and intracellular signals, such therapies may require the application of more than a single growth factor. We examined the effect of 2 endothelial cell-specific growth factors, angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF), on primary cultured porcine coronary artery endothelial cells. VEGF, but not Ang1, increased DNA synthesis and cell number. Ang1 or VEGF induced migration and sprouting activity, increased plasmin and matrix metalloproteinase-2 secretion, and decreased tissue inhibitors of metalloproteinase type 2 secretion. A combination of the submaximal doses of Ang1 and VEGF enhanced these effects and was more potent than the maximal dose of either alone. In a rabbit ischemic hindlimb model, a combination of Ang1 and VEGF gene delivery produced an enhanced effect on resting and maximal blood flow and capillary formation that was greater than that of either factor alone. Angiographic analyses revealed that larger blood vessels were formed after gene delivery of Ang1 or Ang1 plus VEGF than after VEGF gene delivery. These results suggest that combined treatment of Ang1 and VEGF could be used to produce therapeutic vascularization.     

Ethnic variation in hypertension among premenopausal and perimenopausal women: Study of Women's Health Across the Nation

Data are sparse regarding hypertension prevalence, treatment, and control among some ethnic groups of American women. Furthermore, the effects of ethnicity on hypertension, independent of other factors that vary with ethnicity, are poorly understood. We examined the prevalence of hypertension (defined as systolic > or =140 or diastolic > or =90 mm Hg or receiving treatment), treatment, and control (to <140/<90 mm Hg) in a multiethnic study of premenopausal and perimenopausal women. Stepwise multivariable logistic regression was used to select covariates associated with hypertension. Among 3292 women, 46.9% were white, 28.3% were black, 8.7% were Hispanic, 7.6% were Chinese, and 8.5% were Japanese. Among these 5 ethnic groups, respectively, there was substantial variation in prevalence of normal blood pressure levels (<120/<80 mm Hg; 59.9%, 35.4%, 16.8%, 67.2%, and 63.7%) and hypertension (14.5%, 38.1%, 27.6%, 12.8%, and 11.0%). After multivariable adjustment, hypertension prevalence was 2 to 3x higher among black and Hispanic women but similar among Chinese and Japanese women compared with white women. Among hypertensive participants, prevalence of antihypertensive treatment was highest among blacks (58.9%) and whites (55.2%) and lowest among Chinese (34.4%). Prevalence of control to goal blood pressure levels was highest among whites (43.0%) and Japanese (38.7%) and markedly lower among Hispanic women (11.4%). Compared with whites, black and Hispanic women have significantly higher prevalence of hypertension independent of other factors, whereas Chinese and Japanese women have similar prevalence. Treatment and control rates vary considerably across ethnicities. Greater efforts must be made to improve hypertension awareness, treatment, and control in all middle-aged women, particularly those in ethnic minority groups.     

Dissolution of peripheral arterial thrombi by ultrasound

BACKGROUND. We have previously shown that continuous-wave ultrasound can rapidly dissolve human thrombi in vitro, with 99% of all residual particles measuring less than 10 microns in diameter. To assess the effects of pulsed-wave ultrasound energy on whole blood clots, 1) in vitro studies were preformed to assess precisely the rates of clot disruption and to quantify particulate size, and 2) in vivo studies were performed to assess the efficacy and safety of catheter-delivered ultrasound for intra-arterial thrombus dissolution. METHODS AND RESULTS. In vitro, we studied 50 samples of human whole blood clots and using an 89-cm-long wire probe, applied pulse-wave energies from 8 to 23 W. The corresponding peak-to-peak tip displacement range was 63.5 - 102 microns. We studied arterial thrombosis in vivo in 21 canine superficial femoral arteries. To produce an acute thrombosis, 200 units of thrombin followed by 2 ml of 72-hour-old autologous clot were injected into a 5-7-cm segment of femoral artery and left to coagulate for 2 hours. Ultrasound energy was intermittently applied at a frequency of 20 kHz with a prototype ultrasound wire ensheathed in a catheter and directed to clots by fluoroscopy. In nine cases, angioscopic guidance was used to put the probe into direct contact with the intra-arterial thromboses. In vitro clot dissolution times were inversely related to the ultrasound power output (r = 0.95). All in vivo canine thromboses were disrupted in 4 minutes or less. All successful recanalizations were confirmed by angiography and in nine cases by angioscopy as well. Angioscopy demonstrated that probe activation caused rapid clot disruption. Histological studies of the vessels showed no evidence of thermal or cavitation injury, occlusive distal embolization, or perforation. CONCLUSIONS. Our findings in this experimental canine model suggest that ultrasound clot dissolution has the potential to be an effective and safe alternative to current treatment modalities for peripheral arterial thrombosis.