Synergistic effect of Co–Ni co-bridging with MoS2 nanosheets for enhanced electrocatalytic hydrogen evolution reactions

The depletion of fossil fuels and associated environmental problems have drawn our attention to renewable energy resources in order to meet the global energy demand. Electrocatalytic hydrogen evolution has been considered a potential energy solution due of its high energy density and environment friendly technology. Herein, we have successfully synthesized a noble-metal-free Co–Ni/MoS₂ nanocomposite for enhanced electrocatalytic hydrogen evolution. The nanocomposite has been well characterized using HRTEM, elemental mapping, XRD, and XPS analysis. The as-synthesized nanocomposite exhibits a much smaller onset potential and better current density than those of Co–MoS₂, Ni–MoS₂ and MoS₂, with a Tafel value of 49 mV dec⁻¹, which is comparable to that of a commercial Pt/C catalyst. The synergistic effect and interfacial interaction of Co–Ni bimetallic nanoparticles enhances the intrinsic modulation in the electronic structure resulting in an improved HER performance. Moreover, the electrochemical impedance spectroscopic results suggest smaller resistance values for the Co–Ni/MoS₂ nanocomposite, compared to those for the charge transfer of bare nanosheets, which increase the faradaic process and in turn enhance the HER kinetics for a better performance. Our as-synthesized Co–Ni/MoS₂ nanocomposite holds great potential for the future synthesis of noble-metal-free catalysts.

A noble-metal-free Co–Ni/MoS₂ nanocomposite was synthesized, which showed enhanced electrocatalytic hydrogen evolution performance.     

Novel revaprazan-loaded gelatin microsphere with enhanced drug solubility and oral bioavailability

Abstract

To develop a novel revaprazan-loaded gelatine microsphere with enhanced solubility and oral bioavailability, numerous gelatine microspheres were prepared using a spray-drying technique. The impact of gelatine amount on drug solubility in the gelatine microspheres was investigated. The physicochemical properties of the selected gelatine microsphere, such as shape, particle size and crystallinity, were evaluated. Moreover, its dissolution and pharmacokinetics in rats were assessed in comparison with revaprazan powder. Amongst the gelatine microspheres tested, the gelatine microsphere consisting of revaprazan and gelatine (1:2, w/w), which gave about 150-fold increased solubility, had the most enhanced drug solubility. It provided a spherical shape, amorphous drug and reduced particle size. Furthermore, it gave a higher dissolution rate and plasma concentration than did revaprazan powder. Particularly, it gave about 2.3-fold improved oral bioavailability in comparison with revaprazan powder. Therefore, this novel gelatine microsphere system is recommended as an oral pharmaceutical product of poorly water-soluble revaprazan.     

Hemodialysis access success: beyond the operating room

BACKGROUND: Publication of the Kidney Disease Outcomes Quality Initiative (KDOQI) Guidelines has reinforced an already increased focus within the Veterans Health Administration (VHA) on arteriovenous (AV) hemodialysis (HD) vascular access. Meeting these KDOQI goals has been the responsibility of individual VHA centers. We responded by organizing a dedicated HD AV clinic to provide preoperative evaluation and postoperative follow-up. METHODS: The records of 130 patients referred from January 2004 through June 2006 to our AV HD clinic were retrospectively reviewed. A minimum of 6 months of postoperative follow-up was required. RESULTS: AV fistulae were performed in 71% of the patients, with approximately 45% being Brescia-Cimino fistulae. Importantly, only 38% of AV fistulae matured and were used without secondary intervention. The remaining 62% of AV fistulae each required 2.2 +/- .3 interventions. The final AV fistula use rate was approximately 85%. CONCLUSIONS: To meet these KDOQI guidelines, the VHA should continue to support the concept of dedicated AV HD teams and clinics. This is essential because the majority of our new AV fistulae required secondary intervention for AV fistulae maturation and use. A dedicated HD access team should better be able to assess AV fistula maturation and organize subsequent intervention to promote AV fistulae use.     

Management of Advanced Colon Cancer in a Community Hospital—Impact of Age on Clinical Management and Survival

Purpose  

Colon cancer is more common in the elderly than in younger and middle-aged people. Cancer clinical trials focus more on younger patients and the management of elderly patients with advanced disease is still unclear.     

Studies of gastric emptying time in patients with non-ulcer dyspepsia

PURPOSE: To assess the gastric emptying pattern of a standardized solid meal in patients with non-ulcer dyspepsia by using scintigraphic techniques. METHODS: Results for the half-emptying time for solids (T1/2) and percent clearance of solid meal at 60 min (C60) of patients (n=35) having non-ulcer dyspepsia according to Rome II criteria were compared with age- and sex-matched controls (n=28). Gastric emptying was studied by using egg omelette labelled with Tc tin colloid. Data acquisition was done using two protocols: dynamic acquisition was performed for the first 100 min and then static acquisition was carried out for up to 4 h. T1/2 and C60 were calculated from the computer-generated time-activity curve. RESULTS: The normal range of T1/2 was 29-88 min (mean+/-2 SD) among the control group. The mean T1/2 of the patient group was 160.1+/-96.1 min (P<0.01). Twelve of 22 male patients and 11 of 13 female patients had prolonged T1/2. The normal range of C60 was 92-28% (mean+/-2 SD) in the control group. The mean C60 of the patient group was 33.1+/-18.5% (P<0.01). Fifteen of 22 male patients and 11 of 13 female patients had shortened C60. CONCLUSION: Gastric emptying is significantly delayed in both men and women having non-ulcer dyspepsia as the T1/2 is prolonged and the C60 is shortened in a significant number of these patients. Radionuclide tests might offer an objective way of assessing this particular aspect of gastric physiology.     

HPTLC Method for the Simultaneous Estimation of Emtricitabine and Tenofovir in Tablet Dosage Form

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the estimation of emtricitabine and tenofovir simultaneously in combined dosage form. The stationary phase used was precoated silica gel 60F 254. The mobile phase used was a mixture of chloroform: methanol (9:1 v/v). The detection of spots was carried out at 265 nm. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 1000 ng with regression coefficient of 0.9995. The proposed method can be successfully used to determine the drug content of marketed tablet formulation.     

Self-calibration method for radial GRAPPA/k-t GRAPPA.

Generalized autocalibrating partially parallel acquisitions (GRAPPA), an important parallel imaging technique, can be easily applied to radial k-space data by segmenting the k-space. The previously reported radial GRAPPA method requires extra calibration data to determine the relative shift operators. In this work it is shown that pseudo-full k-space data can be generated from the partially acquired radial data by filtering in image space followed by inverse gridding. The relative shift operators can then be approximated from the pseudo-full k-space data. The self-calibration method using pseudo-full k-space data can be applied in both k and k-t space. This technique avoids the prescans and hence improves the applicability of radial GRAPPA to image static tissue, and makes k-t GRAPPA applicable to radial trajectory. Experiments show that radial GRAPPA calibrated with pseudo-full calibration data generates results similar to radial GRAPPA calibrated with the true full k-space data for that image. If motion occurs during acquisition, self-calibrated radial GRAPPA protects structural information better than externally calibrated GRAPPA. However, radial GRAPPA calibrated with pseudo-full calibration data suffers from residual streaking artifacts when the reduction factor is high. Radial k-t GRAPPA calibrated with pseudo-full calibration data generates reduced errors compared to the sliding-window method and temporal GRAPPA (TGRAPPA).     

Suicides among Danish cancer patients 1971-1999

Compared to the general population, the suicide risk among Danish cancer patients diagnosed in 1971-1986 was increased by 50% for men and 30% for women. We updated the earlier study to evaluate both long-term and recent trends in the suicide risk. Cancer patients with a first cancer diagnosed between 1971 and 1999 in Denmark were followed-up for completed suicide through 1999. Excluding nonmelanoma skin cancer, 564 508 cancer patients were included and 1241 suicides observed. Both the standardised mortality ratio (SMR) of suicide relative to the general population and the suicide rates were analysed with Poisson regression methods. The overall SMR was increased to 1.7 (95% CI. 1.6-1.9) for men and 1.4 (95% CI: 1.3-1.5) for women. Following the cancer diagnosis, the suicide risk was highest in the first 3 months for men and between months 3 and 12 for women. The risk was higher for nonlocalized cancer and for cancers with perceived poor prognosis. Breast cancer patients had a higher risk than other cancer patients with similar good prognosis. The suicide rates among cancer patients decreased with calendar time, but less so than the rates in the general population. The suicide risk among cancer patients has not decreased as much as in the Danish population and reasons for this should be explored. Breast cancer might be believed by patients to be more life threatening than it is. Assessment and treatment of depression could improve the quality of life for cancer patients who suffer from unrecognised depressions and in turn reduce the risk of suicide in cancer patients.