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Gas–liquid jet flow is proved to be capable of inducing chemical effects which can lead to the decomposition of methylene blue.

Efficient, accurate and reliable detection and monitoring of H2S is of significance in a wide range of areas: industrial production, medical diagnosis, environmental monitoring, and health screening. However the rapid corrosion of commercial platinum-on-carbon (Pt/C) sensing electrodes in the presence of H2S presents a fundamental challenge for fuel cell gas sensors. Herein we report a solution to the issue through the design of a sensing electrode, which is based on Pt supported on mesoporous titanium chromium nitrides (Pt/Ti0.5Cr0.5N). Its desirable characteristics are due to its high electrochemical stability and strong metal-support interactions. The Pt/Ti0.5Cr0.5N-based sensors exhibit a much smaller attenuation (1.3%) in response to H2S than Pt/C-sensor (40%), after 2 months sensing test. Furthermore, the Pt/Ti0.5Cr0.5N-based sensors exhibit negligible cross response to other interfering gases compared with hydrogen sulfide. Results of density functional theory calculation also verify the excellent long-term stability and selectivity of the gas sensor. Our work hence points to a new sensing electrode system that offers a combination of high performance and stability for fuel-cell gas sensors.

Efficient, accurate and reliable detection and monitoring of H

In this work, a unique carbon-doped NiO nanostructure (denoted as C/NiO) was synthesized via a facile precipitation/reduction reaction, followed by a subsequent oxidation process. The successful in...

The electronic structures and optical properties of La, C-codoped TiO2 were investigated by the first-principles plane-wave ultrasoft pseudopotential method. Our calculations suggest that the micro-structures of La-C codoped system is different from that of TiO2, and the hole effective mass is increased by La-doping, which can create holes in the valence band; Nonmetal C doping can narrow the band gap of TiO2 and enhance the photo-catalytic activity by the formation of localized mid-gap state originated from C 2p states above the top of the valence band; Metal La and nonmetal C co-doping could induce a synergistic effect, the doping of La atoms leads the redistribution of C 2p states in C atoms, which provide more electrons to participate into the 3d states of Ti atoms. The charge compensation effects between Ti 3d and C 2p produce impurity levels, which reduce the band gaps and enhance the carrier concentration, meanwhile La ions are not easy to enter the lattice of TiO2, which may form hetero-junction structure of La2O3-TiO2 with better dispersion in the bulk phase of TiO2 to limit the recombination of photo-generated electron hole pairs. The calculated results of optical properties show that C-TiO2 and La-C-TiO2 systems exhibit good visible absorption and the doping is beneficial to the propagation of light in the doped TiO2.

Background: Few studies have examined the association between treatment given time and clinical outcomes, which is indeed of great importance to clinical management of coronavirus disease 2019 (COVID-19). We performed this study to explore whether early treatment brings favorable clinical outcomes. Methods: In this retrospective multicenter study, we included patients aged 18 to 87 years with confirmed COVID-19 on admission from 54 hospitals in nine provinces of China from 21 January to 10 March, 2020. Final date of follow-up was March 17, 2020. All patients were treated by Lung cleansing & detoxifying decoction combined with western medicine. Patients were divided into four groups according to the interval from the first date of onset of symptoms to the date of starting a treatment, i.e., ≤1 week group (≤7 days), 1-2 weeks group (>7 days and ≤14 days), 2-3 weeks group (>14 days and ≤21 days) and >3 weeks group (>21 days). Multivariable Cox proportional hazard ratio (HR) models were used to estimate unadjusted and adjusted HRs and 95% confidence intervals (CIs) for the association between the treatment given time and clinical outcomes (time to recovery, days of viral shedding, duration of hospital stay, course of disease, fever and CT images). Findings: Of the 782 patients (median age was 46 years old, and 405 (52%) were male), there were 321 (41%) patients in ≤1 week group, 221 (28%) in 1-2 weeks group, 123 (16%) in 2-3 weeks group and 117 (15%) in >3 weeks group. Compared to patients in later treatment group (greater than 3 weeks), patients in earlier treatment groups of less than 1 week, 1 to 2 weeks, or 2 to 3 weeks had higher likelihood of recovery, with adjusted HR (95% CI) of 3.81 (2.65-5.48), 2.63 (1.86-3.73) and 1.92 (1.34-2.75), respectively. The median days of viral shedding was 13 days and 12 days in 2-3 weeks group and 3 weeks group (P=0.0137). The median course of disease decreased from 34 days to 24 days, 21 days and 18 days when treatment was given every one week in advance compared to that was given later than 3 weeks from the onset of symptoms (P

Background: Novel coronavirus pneumonia (NCP) is often changing rapidly and fatal. Early detection and early triage of coronavirus disease 2019 (Covid-19) is the key to success management of the disease. An easily obtainable yet accurate variable for both diagnosis and prognosis is urgently needed. We aim to report predictive Value of the Neutrophil-to-Lymphocyte Ratio(NLR) for diagnosis and worse clinical course of the COVID-19, which have not been well demonstrated. Methods: Our study consisted of two stages, at the first stage, a retrospective, single-center, cohort study including was conducted in Heilongjiang, on admission, demographic, clinical, and laboratory data were collected and compared between patients with COVID-19 and patients with non COVID-19; we used multivariable logistic regression methods to explore the risk factors associated with COVID-19;A receiver operating characteristic(ROC) analysis was conducted to calculate the area under the curve(AUC) to assess predictive value of NLR for diagnosis of COVID 19. At the second stage, we conducted retrospective, multi-center and large sample study in 43 hospitals from ten provinces of China, COVID-19 patients with laboratory-confirmed divided into three groups including mild cases, ordinary cases and severe cases. Multivariate logistic regression methods were used to identify the risk factors for the deterioration of COVID-19, along with, a receiver operating characteristic (ROC) curve was also drawn to assess impact on the clinical course of the COVID-19. Findings: We recruited a total of 635 patients with COVID-19 and 27 cases with non COVID-19(Viral pneumonia) from 28 January to 25 February. A total of 88 cases were enrolled with a retrospective, single-center, cohort study from Heilongjiang province, of these, COVID-19 cases were 61(69%) and non COVID-19 cases were 27(31%). On admission, fever (69%) was the most common symptoms, cough (56%) and fatigue(53%). An average(SD) of NLR of COVID-19 patients and non- COVID-19 patients were3.48±2.04 and 2.21±1.14, respectively. multivariable regression showed increasing odds of COVID-19 patients associated with NLR(odds ratio 1.752, 95% CI 1.111-2.763, per 1 unit increase; p=0.016). In addition, the area under the curve (AUC) of NLR was 0.707 and cutoff value was 2.22. At the second stage, 635 patients with COVID were enrolled with a retrospective, multi-center, large sample study in the 43 settings from 10 provinces, of these, mild case were 86(14%), ordinary cases [486(76%)],severe cases[63(10%)], common symptoms was at onset of disease were cough[356(56%)], an average of NLR of 635 patients was 4.04±4.68, and elevated NLR with the deterioration of clinical course[mild case(2.73±2.28), ordinary cases(3.58±3.07), severe cases(9.38±10.52), P

A room temperature based environmentally friendly aqueous solution synthesis route was developed to fabricate highly dispersed small SnO2 nanoparticles (3–5 nm) without the application of any pressurized reaction vessel or organic solvents. The subsequent treatments, that is, dialyzing and freezing, allow for the acquision of dual-function nanostructures with sheet-like feature and large aspect ratio except for the ordinary irregular aggregates. Dye-sensitized solar cells (DSCs) constructed with the resultant multifunctional SnO2 showed an outstanding photovoltaic conversion efficiency (PCE) of 6.92% and an unexpected JSC of 19.5 mA cm–2 at an optimized thickness of 14.1 μm. The excellent performance can be ascribed to the effective coordination of the favorable features (i.e., strong light scattering, large dye loading capability, and fast electron transport) via rational film thickness control as indicated by diffused reflectance spectra, UV–vis absorption spectra, and electrochemical impedance spectros...

Multishell, stable, porous metal-oxide microspheres (Ni–Co oxides, Co3O4 and NiO) have been synthesized through the amorphous coordination polymer-based self-templated method. Both oxides of Ni and Co show poor selectivity to xylene, but the composite phase has substantial selectivity (e.g., Sxylene/Sethanol = 2.69) and remarkable sensitivity (11.5–5 ppm xylene at 255 °C). The short response and recovery times (6 and 9 s), excellent humidity-resistance performance (with coefficient of variation = 11.4%), good cyclability, and long-term stability (sensitivity attenuation of ∼9.5% after 30 days and stable sensitivity thereafter) all show that this composite is a competitive solution to the problem of xylene sensing. The sensing performances are evidently due to the high specific surface area and the nano-heterostructure in the composite phase.

In this work, we concentrate on the investigation of the fundamental effects of annealing temperatures on the synthesized polydisperse of ZnO aggregates for the exploration of effective electrode material for dye-sensitized solar cells (DSCs). Systematic characterizations including TEM, SEM, BET analysis, XRD, and r-PL were performed for the ZnO aggregates annealed at various temperatures, and the results revealed that the morphology of aggregates, crystal size of primary particle, crystallinity, specific surface areas and the surface states largely depends on the annealing temperature. The photoelectrical efficiency tests demonstrated that the ZnO aggregates annealed at 450 °C exhibited the highest efficiency of 5.10%. The excellent performance could mainly originate from the more efficient light harvesting property of the resulted ZnO photoanode indicated by the incident photon-to-current efficiency (IPCE) and the accelerated electron transport within the ZnO film testified by electrochemical impedance spectroscopy (EIS). Moreover, the combination of the composition control with the introduction of both a ZnO compact layer (CL) and a TiO 2 protecting layer (PL) was simultaneously integrated into one photoanode film for the first time. As a consequence, an impressive power conversion efficiency of 5.83% was achieved with the new photoanode architecture, an improvement of 39.5% over the unmodified DSC. The synergistically reduced charge-transport resistance and suppressed electron recombination are regarded to be the key element for outstanding performance.

The task of control synthesis of Markovian jump nonlinear system is well investigated through giving a new fuzzy switching controller aiming at easing the conservatism than before. Compared with previous results, less conservative stabilization conditions for the considered discrete-time Markovian jump fuzzy system can be gained which lead to wider application of the proposed theoretical method. In the analysis and derivation process, some important information hidden in the fuzzy basis function is well utilized and thus a new scheme of fuzzy switching control law is presented to reduce the conservatism that is caused by ignoring those important information hidden in the fuzzy basis function in the literature. Finally, the validity and advantage of the proposed method over the recent one is also demonstrated by controlling an inverted pendulum model.

A facile one-pot approach was developed for the synthesis of ZnO nanorods (NRs)/nanoparticles (NPs) architectures with controllable morphologies. The concrete state of existence of NPs and NRs could rationally be controlled through reaction temperature manipulation, i.e., reactions occured at 120, 140, 160, and 180 &deg, C without stirring resulted in orderly aligned NRs, disordered but connected NRs/NPs, and relatively dispersed NRs/NPs with different sizes and lengths, respectively. The as-obained ZnO nanostructures were then applied to construct photoanodes of dye-sensitized solar cells, and the thicknesses of the resultant films were controlled for performance optimization. Under an optimized condition (i.e., with a film thickness of 14.7 &micro, m), the device fabricated with the material synthesized at 160 &deg, C exhibited the highest conversion efficiency of 4.30% with an elevated current density of 14.50 mA&middot, cm&minus, 2 and an open circuit voltage of 0.567 V. The enhanced performance could be attributed to the coordination effects of the significantly enhanced dye absorption capability arising from the introduced NPs and the intrinsic fast electron transport property of NRs as confirmed by electrochemical impedance spectroscopy (EIS) and ultraviolet&ndash, visible (UV&minus, vis) absorption.

Iodine doped TiO2 with different iodine/Ti molar ratios has been firstly synthesized with a low temperature hydrothermal route and has been studied systematically in photocatalysis under visible light condition. The resulting iodine doped TiO2 were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance investigations were conducted by means of the degradation of Rhodamine B (RhB) under the visible light irradiation in aqueous solution. Under an optimized I/Ti doping ratio of 10 mol%, the photocatalytic performance is greatly better, with degradation efficiency of 95%, which is almost double that of pure TiO2. The superior photocatalytic activity of iodine-doped TiO2 could be mainly attributed to extended visible light absorption originated from the formation of continuous states existed in the band gap of the doped TiO2 introduced by iodine. Active oxygen species, that is, (OH)-O-center dot and O-2(-), were evidenced to be involved in the degradation process and a possible mechanism was also proposed.

The hetero-junctions of LaMnO3 and g-C3N4 nano-materials are expected to have suitable band structure for the Z-scheme mechanism, but the electronic structures and interfaces have been scarcely studied. In this work, g-C3N4/LaMnO3 hetero-junction composed of g-C3N4 and LaMnO3 layers is studied using the DFT calculations with plane-wave ultrasoft pseudopotential basis sets. The calculated g-C3N4/LaMnO3 heterostructure has a small lattice-mismatch compared with LaMnO3 and g-C3N4. There are reformed Mn-N bonds across the interface, which indicates the strong interaction existing in two layers between LaMnO3 and g-C3N4. When g-C3N4 and LaMnO3 are in contact, the electrons will transfer from LaMnO3 layer to g-C3N4 layer. On the basis of the band structure analysis, the photo-generated electrons in LaMnO3 can combine with the photo-induced holes in g-C3N4, which leads the higher reduction ability of photo-generated electrons in g-C3N4, and the stronger oxidation of photo-induced holes in LaMnO3. As a result, the Z-scheme heterojunction could be generated between the g-C3N4 layer and LaMnO3 layer, which not only has the better visible light adsorption capability, but also the more efficient charge carrier separation.

Graphical abstract, The coronavirus disease 2019 (COVID-19) epidemic has been almost controlled in China under a series of policies, including “early diagnosis and early treatment”. This study aimed to explore the association between early treatment with Qingfei Paidu decoction (QFPDD) and favorable clinical outcomes. In this retrospective multicenter study, we included 782 patients (males, 56 %; median age 46) with confirmed COVID-19 from 54 hospitals in nine provinces of China, who were divided into four groups according to the treatment initiation time from the first date of onset of symptoms to the date of starting treatment with QFPDD. The primary outcome was time to recovery; days of viral shedding, duration of hospital stay, and course of the disease were also analyzed. Compared with treatment initiated after 3 weeks, early treatment with QFPDD after less than 1 week, 1-2 weeks, or 2-3 weeks had a higher likelihood of recovery, with adjusted hazard ratio (HR) (95 % confidence interval [CI]) of 3.81 (2.65–5.48), 2.63 (1.86-3.73), and 1.92 (1.34-2.75), respectively. The median course of the disease decreased from 34 days to 24 days, 21 days, and 18 days when treatment was administered early by a week (P < 0.0001). Treatment within a week was related to a decrease by 1-4 days in the median duration of hospital stay compared with late treatment (P

Fe-Doped NiO multi-shelled microspheres have been synthesized via a facile hydrothermal reaction. Various characterization techniques were introduced to investigate the structure and morphology of the as-prepared Fe-doped NiO multi-shelled microspheres. SEM and TEM observations showed that NiO microspheres are about 500 nm in diameter and with three shells. The Fe-doped NiO multi-shelled microspheres were investigated systematically as gas sensing materials for chemiresistive semiconductor-based gas sensors. The results showed that the 1.92 at% Fe-doped NiO (1.92Fe-NiO) multi-shelled microspheres exhibited enhanced gas sensing performance compared to the pure NiO multi-shelled microspheres. The gas response of 1.92Fe-NiO multi-shelled microspheres to 100 ppm butanol was 45.1 at 140 °C, which revealed a remarkable improvement over the pure NiO multi-shelled microspheres (6.80). The increased response of 1.92Fe-NiO multi-shelled microspheres may be attributed to the incorporation of Fe ions into NiO nanocrystals, which adjusted the carrier concentration and caused an increase in the oxygen species on the adsorbed surface. Therefore, the Fe-doped NiO multi-shelled microspheres should be a promising material for high performance butanol gas sensors.

Both pure and Mn(II)-doped ZnO hollow structures were synthesized by a solvothermal reaction, and their phase structures, morphologies and elemental composition were characterized. SEM and TEM observations show the pure ZnO and the Mn(II)-doped ZnO balls to possess similar hollow structure with a particle size of about 1.5 μm. Their sensing properties were investigated, and the composite containing 1 atom% of Mn(II) (1% Mn-ZnO) is found be display the highest selectivity for acetone. The detection limit is 100 ppm acetone at 234 °C which is 4.6 times lower than that of the pure ZnO. In addition, the response time is shorter. Graphical abstract ZnO and Mn-doped ZnO hollow balls were prepared by a hydrothermal method, and their gas-sensing properties were investigated. Zinc(II) oxide doped with 1 atom% Mn(II) demonstrated an outstanding sensing behavior towards acetone vapors.

We report the rational surface engineering of ZnO photoanode films by strict control of the TiO2 precursors for the facile design of hybrid structures and dye-sensitized solar cells (DSSCs) with increased energy conversion efficiencies. The effects of typical Ti sources [i.e., tetrabutyl titanate (TBOT), titanium isopropoxide (TTIP), and titanium tetrachloride (TiCl4)] on the ZnO film morphology, charge transfer, and DSSC performance were investigated systematically. The testing results revealed that TBOT-treated ZnO film exhibited the highest power conversion efficiency (PCE) and short circuit current density (Jsc) of 4.92% and 12.49 mA/cm2, respectively, which were largely improved compared with those of TTIP- and TiCl4-treated ZnO films under the same conditions. The excellent performance of TBOT-treated ZnO is mainly ascribed to improved light harvesting and increased charge-recombination resistance. Therefore, TBOT can be considered as a promising alternative for constructing TiO2/ZnO hybrid structur...

Hierarchical SnO2 nanocrystallites aggregates (NAs) were prepared with a simple room temperature&ndash, based aqueous solution method followed by simple freeze-drying treatment. The as-prepared SnO2 NAs were subsequently combined with SnO2 nanosheet&ndash, based structures from the viewpoint of a function-matching strategy, and under an optimized condition, a power conversion efficiency (PCE) of 5.59% was obtained for the resultant hybrid photoanode, a remarkable 60% enhancement compared to that of dye-sensitized solar cells (DSCs) fabricated with bare SnO2 NAs architecture. The significantly enhanced efficiency can be attributed to the combination of the desirable electron transport property obtained by the intentionally introduced SnO2 nanosheets (NSs) and the effectively retained inherent characteristics of SnO2 NAs, i.e., large surface area and strong light-scattering effect. This work provides a promising approach for the rapid development of highly efficient SnO2 photoanode film-based DSCs with the properties of simplicity of operation and control over the photoanode composition.