Niobium-doped nanofibers elaborated by facile, single-step electrospinning present a higher rate capability in electrochemical cycling experiments than nondoped materials. This is attributed to the ...reduction of Li+ diffusion path lengths and enhanced intimate interparticle contact, in combination with improved intraparticle conductivity. Niobium doping has a significant effect on the electronic structure and provokes a substantial decrease in particle size.
Electrospun carbon and Nb-doped TiO2 nanofibres (CNFs, TNFs) have been investigated as electrocatalyst supports for polymer electrolyte membrane fuel cells (PEMFC). The optimal Nb doping amount has ...been identified for TNFs, and thermal treatment of titanium oxide fibres optimised to balance the surface area and electronic conductivity requirements. The most highly conducting material is characterised by a high concentration of surface Ti3+ and Nb4+ (and oxygen vacancies). Pt nanoparticles of average diameter of 2.3 nm were loaded onto 10%at Nb doped-TiO2, retained as the best candidate for further electrochemical analysis, and on CNFs, using a microwave-assisted polyol method. Significantly higher electrochemically active surface area was retained after voltage cycling to 1.2 V for Pt supported on TNF (73%) than on CNFs, where only 8% of the original ECSA was conserved after 1000 voltammetric cycles. The mass activity was also slightly higher for the titanium oxide based electrodes in the oxygen reduction reaction.
•TiO2 (TNF) and carbon nanofibres (CNF) were obtained by electrospinning/calcination.•Electronic conductivity of TNF was improved by doping and specific thermal treatments.•Pt loaded TNF and CNF were investigated as electrocatalyst supports for PEMFC.•Pt/TNF showed superior electrochemical stability compared to Pt/CNF.
Sodium borohydride NaBH₄-reduced cobalt is a very attractive material in catalyzing NaBH₄ hydrolysis, as it is highly reactive and cost-effective. However, the nature of its catalytically active ...phase is still unknown although it has been mostly suggested as being either cobalt boride such as Co₂B or an alloy Co–B. With the objective to contribute to highlight the real nature of the catalytically active phase, we performed a systematic study focusing on synthesizing different Co catalysts, characterizing them by ICP-AES, N₂ adsorption/desorption, EDS, FTIR, DSC, SEM, TEM and XRD, and testing them in NaBH₄ hydrolysis. Herein, it is showed that, to be highly reactive, the Co catalyst has to be reduced by a boron-containing reducing agent such as NaBH₄ and ammonia borane NH₃BH₃. Furthermore, it has to be amorphous. None of both features were observed in the case of the hydrazine N₂H₄-reduced cobalt. Hence, it is suggested that the presence of boron is necessary to achieve better reactivity through electronic and geometric effects.
The activity/stability towards the ORR of Pt
x
Gd/C nanoalloys has been enhanced by controlling the atmosphere during the dealloying process. By minimising the formation of porous nanoarchitectures, ...the ORR activity is increased, and is accompanied by higher activity retention and attenuation of metal dissolution on cycling to high voltage.
The activity/stability towards the ORR of Pt
x
Gd/C nanoalloys has been enhanced by controlling the atmosphere during the dealloying process.
Background: The potential of autofluorescence bronchoscopy (AFB) to detect precancerous lesions in the central airways and its role in lung cancer screening is uncertain. A study was undertaken to ...evaluate the prevalence of moderate/severe dysplasia (dysplasia II–III) and carcinoma in situ (CIS) using a newly developed AFB system in comparison with conventional white light bronchoscopy (WLB) alone. Methods: In a prospective randomised multicentre trial, smokers ⩾40 years of age (⩾20 pack-years) were stratified into four different risk groups and investigated with either WLB+AFB (arm A) or WLB alone (arm B). Results: 1173 patients (916 men) of mean age 58.7 years were included. Overall (arms A and B), preinvasive lesions (dysplasia II–III and CIS) were detected in 3.9% of the patients. The prevalence of patients with preinvasive lesions in the WLB arm was 2.7% compared with 5.1% in the WLB+AFB arm (p = 0.037). For patients with dysplasia II–III, WLB+AFB increased the detection rate by a factor of 2.1 (p = 0.03), while for CIS the factor was only 1.24 (p = 0.75). The biopsy based sensitivity of WLB alone and WLB+AFB for detecting dysplasia II–III and CIS was 57.9% compared with 82.3% (1.42-fold increase). The corresponding specificity was 62.1% compared with 58.4% (0.94-fold decrease). Conclusions: This first randomised study of AFB showed that the combination of WLB+AFB was significantly superior to WLB alone in detecting preneoplastic lesions. Our findings do not support the general use of AFB as a screening tool for lung cancer, but suggest that it may be of use in certain groups. The precise indications await further study.
Tracheal stenosis is a common complication of intubation with or without subsequent tracheotomy whose management remains poorly defined. Over 600 post-intubation tracheal stenoses have been treated ...in our centre since 1982: the aim of this study was to determine the safety and efficacy of our endoscopic approach.
This retrospective study includes 113 new cases treated between 1998 and 2001. We chose this period to have a standardised technique and a significant number of cases with a sufficiently long follow up (28-78 months). Forty patients who did not meet the criteria for "true stenosis" (granulomas, pseudoglottic stenosis, etc.) were excluded from the study.
73 patients (50+/-21 years) entered the study: 13 (18%) web-like and 60 (82%) complex stenoses. Most web-like stenoses were successfully treated with Laser Assisted Mechanical Dilation (LAMD) alone; among complex stenoses LAMD was sufficient to treat 13 patients (22%), whereas 47 patients (78%) required stent placement: 22 had their stent removed after one year and did not require any further therapy, 13 inoperable patients required permanent stent and 12 were referred to surgery after failure of multiple endoscopic treatments. No permanent complications secondary to endoscopic treatment were observed. 48 patients (66%) obtained a stable, good result with the endoscopic procedure, 13 (18%) required a permanent stent while 12 patients (16%) were referred to surgery.
Our results indicate that the endoscopic treatment of post-intubation tracheal stenoses performed in an expert setting can be considered a safe first-line therapy, leaving some selected cases and the relapsing stenoses, for surgical resection.
We have developed a facile synthesis route to 1D structures of ultrathin polycrystalline hematite and goethite−hematite core−shells. One-dimensional structures of pure hematite and the ...goethite−hematite core−shell with very small diameters were synthesized in aqueous solution at low temperature with a simple, rapid method based on the oxidation of Fe3O4 nanoparticles without using surfactants.
Patients with severe mental illness are falsely characterized as aggressive by the media, perpetuating stigma. While exaggerated, some patients with severe mental illness are more aggressive without ...treatment. Clozapine may have a unique anti-aggressive effect in patients with schizophrenia-related disorders, independent of antipsychotic or sedative effects. Limited data in forensic and involuntary committed patients is currently available.
This study evaluates clozapine's effects on hostility and aggression in court-ordered Black patients.
This study analyzes a subgroup of Black patients from a larger prospective 24-week open-label clozapine study. All patients were involuntarily committed and enrolled from two participating state psychiatric hospitals. The primary outcome measured was total use of ‘as needed’ (PRN) or ‘immediate need’ (STAT) medications for aggression/hostility. Secondary outcomes included number and duration of seclusion and restraint (S/R) episodes, and changes in Brief Psychiatric Rating Scale (BPRS) hostility factor score.
Sixty-nine patients were included in our analysis. Significant reductions were noted in PRN/STAT medication use over time (χ2 = 6.90; p = 0.008) and the BPRS hostility factor score was reduced by 30% over the 24 weeks (F = 4.34, df = 62, p = 0.002).
Treatment with clozapine effectively reduced hostility and aggression within this cohort of involuntarily committed Black patients with mental illness compared to baseline. Specifically, it helped lower the total number of PRN/STAT medication administrations and improved clinician-rated hostility factor scores on the BPRS. Our findings are pertinent as data in forensic settings is lacking and Black patients have been infrequently included in large prospective clinical trials with clozapine.
NCT02404155.
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