Construction of TiO2/WO3/TiO2 double heterojunction films for excellent electrochromic performance.

Electrochromic devices are applied extensively to camouflages, smart windows, heat insulation layers, and automobile rearview mirrors, etc. The amorphous WO3 is a very attractive electrochromic material, whereas it suffers from degradation of optical modulation and reversibility on ion exchange owing to those deep trapped ions with irreversible reaction behavior. Herein, we designed and, by using magnetron sputtering, prepared a composite film with TiO2/WO3/TiO2 double heterojunctions, which is capable of eliminating the deep trapped ions by itself under ultraviolet light (UV) assistance. The electrochromic device based on this composite film, after being recovery by short-time UV irradiation, can maintain a high transmission modulation of 94.72% after 7000 cycles of the voltammetry measurement. This feature allows the device to maintain its initial electrochromic performance after prolonged use. Moreover, the double heterojunction structure can reduce colouring time and enormously improve the colouration efficiency (CE) of electrochromic devices. Experimental research shows that when the thickness of the bottom and upper TiO2 layer of the WO3 film was 145.5 nm and 97.0 nm, respectively, the CE of electrochromic devices reached a perfectly high value (479.3 cm2/C), being much higher than that of WO3 devices (69.5 cm2/C). Functions of the TiO2/WO3/TiO2 double heterojunction in electrochromic device were investigated by combining theoretical analysis and experiment validation, and these results provide a general framework for developing and designing superior electrochromic materials and devices.

Mild Cognitive Impairment Patients Have Higher Regulatory T-Cell Proportions Compared With Alzheimer's Disease-Related Dementia Patients.

Objectives: The role of neuroinflammation in the pathogenesis of Alzheimer's disease (AD) has attracted much attention recently. Regulatory T-cells (Tregs) play an important role in modulating inflammation. We aimed to explore the Treg-related immunosuppression status at different stages of AD. Methods: Thirty healthy control (HC) subjects, 26 patients with mild cognitive impairment (MCI), 30 patients with mild probable AD-related dementia, and 28 patients with moderate-to-severe probable AD-related dementia underwent detailed clinical history taking, structural MRI scanning, and neuropsychological assessment. Peripheral blood samples were taken to measure the percentage of CD4+CD25+CD127low/- Tregs by flow cytometry and the levels of interleukin (IL-10), interleukin (IL-35), and transforming growth factor ß (TGF-ß) by ELISA. Results: The percentage of Tregs in the blood of MCI patients was the highest (9.24%); there was a significant difference between patients with MCI and patients with probable AD-related dementia. The level of TGF-ß in patients with MCI (47.02 ng/ml) was significantly increased compared with patients with AD-related dementia. There were positive correlations between Treg percentage, IL-35, and Mini-mental state evaluation scores in patients with MCI and probable AD-related dementia. Conclusions: Patients with MCI have stronger Treg-related immunosuppression status compared with patients with probable AD-related dementia.

Immediate and late outcomes of stenting for severe extracranial internal carotid artery stenosis in octogenarian patients.

Background: Multiple studies suggest that internal carotid artery stenting can be performed safely in octogenarians with low periprocedural complication rates. However, great concern still exists as to whether these patients will gain long-term benefits from this procedure given their advanced age and uncertain life expectancy. We decided to conduct a retrospective study to determine short-and long-term clinical outcomes and to analyze survival duration in this population. Methods and Results: Sixty-nine consecutive elderly patients with either symptomatic or asymptomatic stenosis ≥70% underwent 86 procedures. Immediate and late outcomes, as well as survival data, were analyzed retrospectively. Mean age was 83.1 ± 2.7 years. Mean survival was 49.3 ± 10.1 months. A complete neurological assessment was obtained at 1 and 2 years in 100% of patients, at 3 years in 90.7% of patients and at 5 years in 84.8% of patients. Two major and one minor ischemic strokes occurred during the periprocedural period. No death, myocardial infarction or intracranial hemorrhage was recorded. The mean follow-up period was 55.4 ± 24.6 months. Four patients experienced a minimum of 1 year of follow-up, and the longest is 8 years. Among the patients with the longest follow-up time, 6 had ischemic strokes, of which 2 were fatal. In total, 17 deaths occurred. Four patients experienced dementia without stroke. Survival at 3 and 5 years was estimated to be 90% and 73%, respectively. Conclusion: This study demonstrated that stenting in octogenarians was safe and effective during the periprocedural period. Long-term follow-up showed a low rate of fatal and nonfatal stroke, and patients survived long enough to benefit from the procedure. However, it was associated with a relatively high rate of long-term event. Though carotid artery stenting is a minimally invasive procedure, it should still be performed with great caution and only in carefully selected patients. The present study suggested that in this age population, carotid artery stenting might be considered as a revascularization option.

Studies on formation and repair of formaldehyde-damaged DNA by detection of DNA-protein crosslinks and DNA breaks.

Formaldehyde (FA) is a genotoxic and mutagenic substance. In 2004, IARC (International Agency for Research on Cancer) concluded that FA is carcinogenic in humans after reevaluating the available evidence on the carcinogenicity of FA. Although many studies have shown that FA had extensive genotoxicity including DNA-protein crosslinks (DPC) and DNA single strand breaks (DSSB), most of these studies only discussed the effects of FA at high levels. In this study, KCl-SDS assay and single cell gel electrophoresis (SCGE) were used to investigate the formation and repair process of FA-induced DPC and DSSB in human peripheral blood lymphocytes and Hela cell lines. KCl-SDS assay was applied to detect DPC induced by liquid FA in human peripheral blood lymphocytes in vitro. The results showed that FA could induce DPC at high levels (> or =50 micro M). By combining the results of KCl-SDS assay and SCGE, it could be determined that FA would induce DNA-DNA crosslinks (DDC) when FA concentration was more than 25 microM. The repair process of FA-induced DPC was studied with KCl-SDS assay in Hela cell lines and the results demonstrated that FA-induced DPC could be significantly repaired after 18 hours. The SCGE was also used to determine FA-induced DSSB and its repair process in Hela cell lines. The results demonstrated that DNA breakages, which is capable of being induced by FA at a low level (<30 microM), enabled to be repaired completely in 90 minutes.

Lactate biosensors for continuous monitoring.

Blood lactate concentration is a highly sensitive measure of tissue oxygen deprivation from ischemia, trauma, and hemorrhage, which can produce life-threatening shock. Significantly, blood lactate is the most reliable end point indicator of resuscitation and predictor of survivability. The need for continuous measurement of blood lactate, and the slowness of discrete conventional photometric assays, is leading to the development of monitoring systems based on electrochemical lactate biosensors. Research and development of both in vivo and ex vivo biosensor systems is ongoing. Ex vivo biosensors are used with implanted microdialysis or ultrafiltration probes. Lactate from the blood diffuses into the dialysate/filtrate is transported outside of the body for measurement. The external biosensors are protected from fouling or contamination from unwanted blood constituents, but at the cost of an inherent delay in response despite system miniaturization. In vivo biosensors provide a direct measurement of blood lactate concentration, providing rapid response to changes in lactate levels. In vivo sensors are placed in the skin or implanted subcutaneously. Response to changes in lactate concentration is rapid, but biocompatibility requirements are more stringent than for ex vivo sensors. As is the case with all microdialysis systems, some in vivo biosensors must be implanted into the body using an insertion needle or surgical means, limiting their use. However, small, inexpensive, disposable in vivo sensors are also being developed which can emplaced and removed by the user.

Oxygen-independent poly(dimethylsiloxane)-based carbon-paste glucose biosensors.

Several silicone oils have been assessed and compared as an internal source of oxygen in connection to their use as binders for carbon-paste glucose biosensors. All four poly(dimethylsiloxane) (PDMS) oils tested a dramatic increase in the oxygen capacity of carbon-paste enzyme electrodes to allow convenient biosensing under severe oxygen-deficit conditions. The resulting oxygen independence is better than that exerted by perfluorocarbon binders or that displayed by mediator-based bioelectrodes. The resistance to oxygen effects is indicated from the identical response (observed in the presence and absence of oxygen) up to 2 x 10(-2) M glucose and the slight (12%) sensitivity loss at 4 x 10(-2) M. The influence of the viscosity of the PDMS binder upon the internal oxygen supply is examined. The PDMS carbon-paste enzyme electrode displays a stable glucose response over prolonged (15 h) operation in an oxygen-free solution. On-line continuous testing indicates favorable dynamic properties with no carry-over effects over the physiological and pathophysiological range (3-12 mM glucose).

Design and Experimental Study of an Over-Under TBCC Exhaust System.

Turbine-based combined-cycle (TBCC) propulsion systems have been a topic of research as a means for more efficient flight at supersonic and hypersonic speeds. The present study focuses on the fundamental physics of the complex flow in the TBCC exhaust system during the transition mode as the turbine exhaust is shut off and the ramjet exhaust is increased. A TBCC exhaust system was designed using methods of characteristics (MOC) and subjected to experimental and computational study. The main objectives of the study were: (1) to identify the interactions between the two exhaust jet streams during the transition mode phase and their effects on the whole flow-field structure; (2) to determine and verify the aerodynamic performance of the over-under TBCC exhaust nozzle; and (3) to validate the simulation ability of the computational fluid dynamics (CFD) software according to the experimental conditions. Static pressure taps and Schlieren apparatus were employed to obtain the wall pressure distributions and flow-field structures. Steady-state tests were performed with the ramjet nozzle cowl at six different positions at which the turbine flow path were half closed and fully opened, respectively. Methods of CFD were used to simulate the exhaust flow and they complemented the experimental study by providing greater insight into the details of the flow field and a means of verifying the experimental results. Results indicated that the flow structure was complicated because the two exhaust jet streams interacted with each other during the exhaust system mode transition. The exhaust system thrust coefficient varied from 0.9288 to 0.9657 during the process. The CFD simulation results agree well with the experimental data, which demonstrated that the CFD methods were effective in evaluating the aerodynamic performance of the TBCC exhaust system during the mode transition.

Stroke-prone renovascular hypertensive rat as an animal model for stroke studies: from artery to brain.

High blood pressure is a main risk factor for both initial and recurrent stroke. Compared to the post stroke situation in normotension, the brain lesion is larger in hypertension, and the treatments may not be as effective. Thus, the results from healthy individuals may not be directly applied to the hypertensive. In fact, the high prevalence of hypertension in stroke patients and its devastating effect urge the necessity to integrate arterial hypertension in the study of stroke in order to better mimic the clinical situations. The first step to do so is to have an appropriate hypertensive animal model for stroke studies. Stroke-prone renovascular hypertensive rat (RHRSP) introduced in 1998, is an animal model with acquired hypertension independent of genetic deficiency. The blood pressure begins to increase during the first week after constriction of bilateral renal arteries, and becomes sustained since around the 3rd month. Because the morphological and physiological changes of cerebral arteries are similar to those in hypertensive patients, the rats represent a higher than 60% incidence of spontaneous stroke. The animal model has several advantages: one hundred percent development of hypertension without gene modification, high similarity to human hypertension in cerebrovascular pathology and physiology, and easy establishment with low cost. Thus, the model has been extensively used in the investigation of ischemic stroke, and has been shown as a reliable animal model. This paper reviewed the features of RHRSP and its applications in the treatment and prevention of stroke, as well as the investigations of secondary lesions postischemic stroke.

Acid stability of carbon paste enzyme electrodes.

This note reports on the unusual protection of several enzymes against harsh pH conditions provided by carbon paste electrodes. Both glucose oxidase and polyphenol oxidase carbon paste amperometric biosensors display a remarkable resistance to acid deactivation compared to conventional biosensors prepared by electropolymeric entrapment of enzymes. For example, the carbon paste enzyme electrodes fully retain their activity upon stressing in strongly acidic conditions (pH approximately 2.0-2.5) for prolonged periods, where conventional (polymer-based) biosensors rapidly lose most of their response. Such unusual acid stability of carbon paste enzyme electrodes is attributed to the "pH memory" of enzymes in the hydrophobic paste environment, to the barrier to hydronium ions provided by the pasting liquid and to decreased conformational mobility.