Visible-Light Harvesting SrTiO3 Solid Solutions for Photocatalytic Hydrogen Evolution from Water.

The fabrication of solid solutions represents a compelling approach to modulating the physicochemical properties of materials. In this study, we achieved the successful synthesis of solid solutions comprising SrTiO3 and SrTaO2N (denoted as (SrTiO3)1-x-(SrTaO2N)x, 0≤x≤1) using the magnesium powder-assisted nitridation method. The absorption edge of (SrTiO3)1-x-(SrTaO2N)x is tunable from 500 to 600 nm. The conduction band minimum (CBM) of (SrTiO3)1-x-(SrTaO2N)x comprises the Ti 3d orbitals and the Ta 5d orbitals, while the valence band maximum (VBM) consists of the O 2p and N 2p orbitals. The microstructure of the (SrTiO3)1-x-(SrTaO2N)x consists of small nanoparticles, exhibiting a larger specific surface area than the parent compounds of SrTiO3 and SrTaO2N. In the photocatalytic hydrogen evolution reaction (HER) with sacrificial reagents, the activity of solid solutions is notably superior to that of nitrogen-doped SrTiO3 and SrTaO2N. This superiority is mainly attributed to its broad light absorption range and high charge separation efficiency, which indicates its potential as a promising photocatalytic material. Moreover, the magnesium powder-assisted nitridation method exhibits obvious advantages for the synthesis of oxynitrides and bears instructional significance for the synthesis of other nitrogen-containing compounds and even sulfur-containing compounds.

Insight into the Key Restriction of BiVO4 Photoanodes Prepared by Pyrolysis Method for Scalable Preparation.

Bismuth Vanadate (BiVO4 ) photoanode has been popularly investigated for promising solar water oxidation, but its intrinsic performance has been greatly retarded by the direct pyrolysis method. Here we insight the key restriction of BiVO4 prepared by metal-organic decomposition (MOD) method. It is found that the evaporation of vanadium during the pyrolysis tends to cause a substantial phase impurity, and the unexpected few tetragonal phase inhibits the charge separation evidently. Consequently, suitably excessive vanadium precursor was adopted to eliminate the phase impurity, based on which the obtained intrinsic BiVO4 photoanode could exhibit photocurrent density of 4.2 mA cm-2 at 1.23 VRHE under AM 1.5 G irradiation, as comparable to the one fabricated by the currently popular two-step electrodeposition method. Furthermore, the excellent performance can be maintained on the enlarged photoanode (25 cm2 ), demonstrating the advantage of MOD method in scalable preparation. Our work provides new insight and highlights the glorious future of MOD method for the design of scale-up efficient BiVO4 photoanode.

Metallic Powder Promotes Nitridation Kinetics for Facile Synthesis of (Oxy)Nitride Photocatalysts.

Nitrogen-containing semiconductors (including metal nitrides, metal oxynitrides, and nitrogen-doped metal oxides) have been widely researched for their application in energy conversion and environmental purification because of their unique characteristics; however, their synthesis generally encounters significant challenges owing to sluggish nitridation kinetics. Herein, a metallic-powder-assisted nitridation method is developed that effectively promotes the kinetics of nitrogen insertion into oxide precursors and exhibits good generality. By employing metallic powders with low work functions as electronic modulators, a series of oxynitrides (i.e., LnTaON2 (Ln = La, Pr, Nd, Sm, and Gd), Zr2 ON2 , and LaTiO2 N) can be prepared at lower nitridation temperatures and shorter nitridation periods to obtain comparable or even lower defect concentrations compared to those of the conventional thermal nitridation method, leading to superior photocatalytic performance. Moreover, some novel nitrogen-doped oxides (i.e., SrTiO3- x Ny and Y2 Zr2 O7- x Ny ) with visible-light responses can be exploited. As revealed by density functional theory (DFT) calculations, the nitridation kinetics are enhanced via the effective electron transfer from the metallic powder to the oxide precursors, reducing the activation energy of nitrogen insertion. The modified nitridation route developed in this work is an alternative method for preparing (oxy)nitride-based materials for energy/environment-related heterogeneous catalysis.

Visible-light-responsive Photocatalyst Based on Nitrogen-doped Bulk Oxide YTaO4-x Ny for Z-scheme Overall Water Splitting.

Nitrogen doping into oxide has been proved to be an effective strategy to extend visible-light utilization of oxides with layered or channeled structure, but it is shortage for the bulk oxides free of layered or channeled structure. Here, we report a novel nitrogen-doped bulk oxide (denoted as YTaO4-x Ny ) with good visible light response. As benefited from the strong hybridization of N 2p and O 2p electronic state according to the density functional theory (DFT) calculations, the band gap (3.6 eV) of YTaO4 precursor was sharply narrowed to 2.4 eV on YTaO4-x Ny due to the obvious uplift of the valence band maximum (VBM). After decorated with the platinum cocatalyst, the Pt/YTaO4-x Ny was used as the H2 -evolving photocatalyst for assembly of Z-scheme overall water splitting system by coupling with the PtOx /WO3 as the oxygen evolution photocatalyst and using the I- /IO3- as the shuttle ions. This work enriches the material database of nitrogen-doped oxide with wide visible light absorption and shows its promising application in solar-to-chemical conversion.

Layered ß-ZrNBr Nitro-Halide as Multifunctional Photocatalyst for Water Splitting and CO2 Reduction.

Developing mixed-anion semiconductors for solar fuel production has inspired extensive interest, but the nitrohalide-based photocatalyst is still in shortage. Here we report a layered nitro-halide ß-ZrNBr with a narrow band gap of ca. 2.3 eV and low defect density to exhibit multifunctionalities for photocatalytic water reduction, water oxidation and CO2 reduction under visible-light irradiation. As confirmed by the results of electron paramagnetic resonance (EPR) and density functional theory (DFT) calculations, the formation of anion vacancies in the nitro-halide photocatalyst was inhibited due to its relatively high formation energy. Furthermore, performance of ß-ZrNBr can be effectively promoted by a simple exfoliation into nanosheets to shorten the carrier transfer distance as well as to promote charge separation. Our work extends the territory of functional photocatalysts into the nitro-halide, which opens a new avenue for fabricating efficient artificial photosynthesis.

Pyrochlore-structural Nd2Ta2O5N2 photocatalyst with an absorption edge of over 600 nm for Z-scheme overall water splitting.

A pyrochlore-structural oxynitride Nd2Ta2O5N2 with a visible light absorption edge of ca. 620 nm was explored for photocatalytic water splitting. Dual functions of Nd2Ta2O5N2 were confirmed by proton reduction and water oxidation half-reactions through separately loading Pt or CoOx as a cocatalyst in the presence of the corresponding sacrificial reagent. Finally, the platinum modified sample (Pt/Nd2Ta2O5N2) was prepared and employed as the H2-evolving photocatalyst to fabricate an effective photocatalytic Z-scheme overall water splitting together with PtOx/WO3 as the O2-evolving photocatalyst and IO3-/I- as shuttle ions under visible light irradiation.

Water-Stable Nickel Metal-Organic Framework Nanobelts for Cocatalyst-Free Photocatalytic Water Splitting to Produce Hydrogen.

Development of water-stable metal-organic frameworks (MOFs) for promising visible-light-driven photocatalytic water splitting is highly desirable but still challenging. Here we report a novel p-type nickel-based MOF single crystal (Ni-TBAPy-SC) and its exfoliated nanobelts (Ni-TBAPy-NB) that can bear a wide range of pH environment in aqueous solution. Both experimental and theoretical results indicate a feasible electron transfer from the H4TBAPy ligand (light-harvesting center) to the Ni-O cluster node (catalytic center), on which water splitting to produce hydrogen can be efficiently driven free of cocatalyst. Compared to the single crystal, the exfoliated two-dimensional (2D) nanobelts show more efficient charge separation due to its shortened charge transfer distance and remarkably enhanced active surface areas, resulting in 164 times of promoted water reduction activity. The optimal H2 evolution rate on the nanobelt reaches 98 µmol h-1 (ca. 5 mmol h-1 g-1) showing benchmarked apparent quantum efficiency (AQE) of 8.0% at 420 nm among water-stable MOFs photocatalysts.

Prediction of Intracerebral Hemorrhage After Endovascular Treatment of Acute Ischemic Stroke: Combining Quantitative Parameters on Dual-Energy CT with Clinical Related Factors.

OBJECTIVES: To evaluate the predictive value of dual-energy CT (DECT) quantitative parameters and clinical influence factors for intracerebral hemorrhage (ICH) complications after endovascular treatment in patients with acute ischemic stroke (AIS). METHODS: Seventy-two consecutive patients who underwent brain DECT immediately after endovascular treatment for AIS from November 2017 to October 2019 were included. Retrospectively, the volume of brain parenchymal hyperdensity area (HDA), the maximum iodine concentration, and maximum CT value on DECT images was evaluated and measured by two radiologists blinded to any clinical information independently. Follow-up CT imaging (24-72 h) were used to assess the development of ICH complications. DECT parameters and clinical influence factors were analyzed by Chi-square test or Fisher's exact test and Mann-Whitney U test. Receiver operating characteristic curves were generated for continuous variables. RESULTS: Follow-up CT images confirmed that forty of 72 patients (55.6%) developed ICH. The volume of HDA, median maximum iodine concentration and maximum CT value between ICH group and non-ICH group were significantly different (P < 0.001). Combining the DECT quantitative parameters with clinical predictors, receiver operating characteristic analysis revealed an area under the curve of 0.985, for identifying patients developing ICH with sensitivity, specificity, positive predictive value and negative predictive value were 90%, 100%, 100% and 88.9%, respectively. CONCLUSIONS: Three quantitative parameters of DECT and clinical predictors showed great predictive performance in identifing ICH complications in patients with brain parenchyma HDA after endovascular therapy, which may contribute to better clinical decision-making.

Synthesis of a Visible-Light-Responsive Perovskite SmTiO2 N Bifunctional Photocatalyst via an Evaporation-Assisted Layered-Precursor Strategy.

Development of visible-light-responsive oxynitride photocatalysts has been highly inspired for promising solar-to-chemical conversion, but the number of Ti-based oxynitrides is scarce because of the relatively low thermal stability of Ti4+ ions under ammonia flow. Here, the feasible synthesis of a novel perovskite SmTiO2 N from the layered NaSmTiO4 precursor is demonstrated to exhibit wide visible-light response with a bandgap of ≈2.1 eV and to show effective water reduction and oxidation functionalities under visible-light irradiation. The successful preparation mainly results from the synergistic effect of the layered structure of NaSmTiO4 and the evaporation spillover of Na+ ions, both of which are favorable for ammonia diffusion to accelerate the substitution of nitrogen to oxygen atoms and to shorten the nitridation time. The thermodynamic and kinetic feasibility of SmTiO2 N for water splitting are investigated in detail, and its optimal apparent quantum efficiency (AQE) of water oxidation reaches 16.7% at 420 ± 10 nm, higher by far than that of most previous visible-light-responsive photocatalysts. Interestingly, a series of oxynitrides RTiO2 N (R = La, Pr, Nd) are similarly synthesized by the alkali-metal evaporation-assisted layered-precursor strategy, demonstrating its generality to prepare visible-light-responsive (oxy)nitride photocatalysts containing reducible metals for solar energy conversion.

Detection of bone marrow edema in osteonecrosis of the femoral head using virtual noncalcium dual-energy computed tomography.

PURPOSE: To determine the diagnostic performance of virtual noncalcium (VNCa) dual-energy computed tomography (DECT) in the detection of bone marrow edema (BME) in participants with osteonecrosis of the femoral head (ONFH). METHODS: In this prospective study, 24 consecutive participants (15 men, 9 women; mean age, 44 years, range, 21-72 years) diagnosed with ONFH who underwent DECT and magnetic resonance imaging (MRI) between September 2019 and January 2020 were involved. Two independent readers visually evaluated color-coded VNCa images using a binary classification (0 = normal bone marrow, 1 = BME). MRI served as the reference standard for the presence of BME. Interobserver agreement for the visual evaluation of VNCa DECT images was calculated with κ statistics. We determined computed tomography (CT) numbers on VNCa images and weighted-average CT sets using region-of-interest-based quantitative analysis. The t-test was used to compare the differences of CT values between BME areas and normal bone marrow areas. Receiver operating characteristic (ROC) curve was used to select an optimal CT values of VNCa images for detecting BME. A p value of <0.05 was considered as statistically significant. RESULTS: The sensitivity, specificity, and accuracy of Reader 1 and Reader 2, respectively, in the identification of BME at DECT were 95 % and 89 % (18 and 17 of 19), 96 % and 96 % (25 and 25 of 26), and 93 % (43 and 42 of 45). Interobserver agreement was excellent (κ = 0.86). The VNCa CT numbers of the BME area and the normal bone marrow area were -28.6 (-17.9--39.4) HU and -97.9 (-91.3--104.4) HU, respectively, with statistical significance (t = -10.6, p < 0.001). The weighted-average CT numbers of the BME area and the normal bone marrow area were 152.4(122.2-182.7) HU and 121.1(103.6-183.6) HU, respectively, with no statistical significance (t = -2.0, p > 0.05). The area under the receiver operating characteristic curve was 0.99 in differentiation of the BME from normal bone marrow. A cut-off value of -57.2 HU yielded overall sensitivity, specificity, and accuracy, respectively, of 95 % (18 of 19), 100 % (26 of 26), and 98 % (44 of 45) detection of BME in participants with ONFH. CONCLUSION: Visual and quantitative analyses of VNCa images shows excellent diagnostic performance for assessing BME in participants with ONFH.

Pleural effusion and ascites in extrarenal lymphangiectasia caused by post-biopsy hematoma: A case report.

BACKGROUND: The renal system has a specific pleural effusion associated with it in the form of "urothorax", a condition where obstructive uropathy or occlusion of the lymphatic ducts leads to extravasated fluids (urine or lymph) crossing the diaphragm via innate perforations or lymphatic channels. As a rare disorder that may cause pleural effusion, renal lymphangiectasia is a congenital or acquired abnormality of the lymphatic system of the kidneys. As vaguely mentioned in a report from the American Journal of Kidney Diseases, this disorder can be caused by extrinsic compression of the kidney secondary to hemorrhage. CASE SUMMARY: A 54-year-old man with biopsy-proven acute tubulointerstitial nephropathy experienced bleeding 3 d post hoc, which, upon clinical detection, manifested as a massive perirenal hematoma on computed tomography (CT) scan without concurrent pleural effusion. His situation was eventually stabilized by expeditious management, including selective renal arterial embolization. Despite good hemodialysis adequacy and stringent volume control, a CT scan 1 mo later found further enlargement of the perirenal hematoma with heterogeneous hypodense fluid, left side pleural effusion and a small amount of ascites. These fluid collections showed a CT density of 3 Hounsfield units, and drained fluid of the pleural effusion revealed a dubiously light-colored transudate with lymphocytic predominance (> 80%). Similar results were found 3 mo later, during which time the patient was free of pulmonary infection, cardiac dysfunction and overt hypoalbuminemia. After careful consideration and exclusion of other possible causative etiologies, we believed that the pleural effusion was due to the occlusion of renal lymphatic ducts by the compression of kidney parenchyma and, in the absence of typical dilation of the related ducts, considered our case as extrarenal lymphangiectasia in a broad sense. CONCLUSION: As such, our case highlighted a morbific passage between the kidney and thorax under an extraordinarily rare condition. Given the paucity of pertinent knowledge, it may further broaden our understanding of this rare disorder.

Comparative analysis of radiation dose and image quality between organ dose modulation and 3D smart mA modulation during head-neck CT angiography.

OBJECTIVE: To assess the difference in absorbed organ dose and image quality for head-neck CT angiography using organ dose modulation compared with 3D smart mA modulation in different body mass indices (BMIs) using an adaptive statistical iterative reconstruction (ASiR-V) algorithm. METHODS: Three hundred patients underwent head-neck CTA were equally divided into three groups: A (18.5 kg/m2≦BMI < 24.9 kg/m2), B (24.9 kg/m2≦BMI < 29.9 kg/m2) and C (29.9 kg/m2≦BMI≦34.9 kg/m2). The groups were randomly subdivided into two subgroups (n = 50): A1-A2, B1-B2 and C1-C2. The patients in subgroups A1, B1 and C1 underwent organ dose modulation with the ASiR-V algorithm, while other patients underwent 3D smart mA modulation. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of all head-neck CT angiography images were calculated. Images were then subjectively evaluated. Mean values of several indices including dose-length product (DLP) were computed. The DLP was converted to the effective dose (ED). SNR, CNR and ED in groups A, B, and C were compared in statistical data analysis. RESULTS: SNR, CNR, and subjective image scores show no statistical differences in three groups (P  >  0.05). However, there is significant difference of ED values (P  <  0.05) . For example, in subgroup A1 mean ED values are 15.30% and 23.66% lower than those in subgroup A2 at thyroid gland and eye lens, respectively. Similar patterns also exist in groups B (B1 vs. B2) and C (C1 vs. C2). CONCLUSIONS: Using organ dose modulation and applying the ASiR-V algorithm can more effectively reduce the radiation dose in head-neck CT angiography than using 3D smart mA modulation, while maintaining image quality. Thus, using organ-based dose modulation has the additional benefit of reducing dose to the thyroid gland and eye lens.