Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffu- sion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially in- creased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion co- efficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3-24 hours after infarction. Apparent diffusion coefficient values at remote regions （cerebellum） varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.

CT Perfusion Imaging Predicts One-Month Outcome in Patients with Acute Spontaneous Hypertensive Intracerebral Hemorrhage

Purpose: Little is known about the relationship between perihematomal perfusion parameters in acute spontaneous hypertensive intracerebral hemorrhage patients and recent outcome. The purpose of this study was to evaluate the relationship between the perfusion parameters of the perihematomal brain tissue and the recent prognosis of patients with acute spontaneous hypertensive intracerebral hemorrhage (shICH) using CT perfusion (CTP) imaging. Methods: Twenty-six patients with clinical and CT diagnosed supratentorial shICH received CTP scanning within 8 - 19 h after symptom onset. At the maximum levels of the hematoma, cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of perihematomal area (isodense within 1cm rim of perilesion area on plain CT) and contralateral mirrored hemisphere were measured, and rCBF, rCBV, rMTT were calculated (ipsilateral/contralateral). The one-month follow-up in accordance with daily living table (Barthel index, BI) by telephone was recorded. Results: The CBV, CBF, and MTT values of perihematoma area were (1.61 ± 1.53) ml·100 g-1, (16.48 ± 12.58) ml·100 g-1·min-1, and (9.12 ± 2.57) s, respectively. (For more information,please refer to the PDF)

Control of mutiple Power Inverters for More Electronics Power Systems:A Review

With the development and utilization of renewable energy,the scaling of microgrid composed of distributed generation systems and energy storing devices,e.g,photovoltaic(PV),wind power,micro gas turbine,fuel cell,are becoming much lager.Research on control of multi-inverter parallel is the focus as the key technique,which can improve the reliability of microgrids.The inverters in the microgrid operate in parallel,which not only facilitates the expansion of the microgrid but also improves the reliability of the operation of the microgrid system in off-grid mode.The key to the parallel operation of the inverter is to achieve even distribution of the load current.In this paper,a comprehensive review on the control strategies of parallel-operated inverters is presented.Also,the detailed analysis,comparison,and discussion on the existing parallel control strategies are investigated.

Magnetic resonance perfusion imaging evaluation in perfusion abnormalities of the cerebellum after supratentorial unilateral hyperacute cerebral infarction

Magnetic resonance imaging （MRI） data of 10 patients with hyperacute cerebral infarction （≤6 hours） were retrospectively analyzed.Six patients exhibited perfusion defects on negative enhancement integral maps,four patients exhibited perfusion differences in pseudo-color on mean time to enhance maps,and three patients exhibited perfusion differences in pseudo-color on time to minimum maps.Dynamic susceptibility contrast-enhanced perfusion weighted imaging revealed a significant increase in region negative enhancement integral in the affected hemisphere of patients with cerebral infarction.The results suggest that dynamic susceptibility contrast-enhanced perfusion weighted imaging can clearly detect perfusion abnormalities in the cerebellum after unilateral hyperacute cerebral infarction.

Self-Assembled Protein Hybrid Nanofibrils for Photosynthetic Hydrogen Evolution

In artificial photosynthesis systems,synthetic diiron complexes are popular[FeFe]-hydrogenase mimics,which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen(H2)generation capability.However,constructing a highly bionic and efficient catalytic hybrid system is a major challenge.Notably,we designed an ideal hybrid nanofibrils system that incorporates the crucial components:(1)a[FeFe]-H2ase mimic,which has a three-arm architecture(named triFeFe)for more interaction sites and higher catalytic activity and(2)uniform hybrid nanofibrils as the biological environment in which cysteine-catalyst coordination and the hydrogen-bonding network play a vital role in both catalyst binding and hydrogen evolution reaction activity.The assembled hybrid nanofibrils achieve efficient H2 generation with a turnover number of 2.3×103,outperforming previously reported diiron catalyst-protein hybrid systems.Additionally,the hybrid nanofibrils work with photosynthetic thylakoids to produce H2,without extra photosensitizers or electron shuttle proteins,which advances the bioengineering of living systems for solar-driven biofuel production.

Wireless whispering-gallery-mode sensor for thermal sensing and aerial mapping

The Internet of Things(IoT)1,2 employs a large number of spatially distributed wireless sensors to monitor physical environments,e.g.,temperature,humidity,and air pressure,and has many applications,including environmental monitoring3,health care monitoring4,smart cities5,and precision agriculture.A wireless sensor can collect,analyze,and transmit measurements of its environment1,2.Currently,wireless sensors used in the IoT are predominately based on electronic devices that may suffer from electromagnetic interference in many circumstances.Being immune to the electromagnetic interference,optical sensors provide a significant advantage in harsh environments6.Furthermore,by introducing optical resonance to enhance light–matter interactions,optical sensors based on resonators exhibit small footprints,extreme sensitivity,and versatile functionalities7,8,which can significantly enhance the capability and flexibility of wireless sensors.Here we provide the first demonstration of a wireless photonic sensor node based on a whisperinggallery-mode(WGM)optical resonator,in which light propagates along the circular rim of such a structure like a sphere,a disk,or a toroid by continuous total internal reflection.The sensor node is controlled via a customized iOS app.Its performance was studied in two practical scenarios:(1)real-time measurement of the air temperature over 12 h and(2)aerial mapping of the temperature distribution using a sensor node mounted on an unmanned drone.Our work demonstrates the capability of WGM optical sensors in practical applications and may pave the way for the large-scale deployment of WGM sensors in the IoT.

Graph convolution machine for context-aware recommender system

The latest advance in recommendation shows that better user and item representations can be learned via performing graph convolutions on the user-item interaction graph.However,such finding is mostly restricted to the collaborative filtering(CF)scenario,where the interaction contexts are not available.In this work,we extend the advantages of graph convolutions to context-aware recommender system(CARS,which represents a generic type of models that can handle various side information).We propose Graph Convolution Machine(GCM),an end-to-end framework that consists of three components:an encoder,graph convolution(GC)layers,and a decoder.The encoder projects users,items,and contexts into embedding vectors,which are passed to the GC layers that refine user and item embeddings with context-aware graph convolutions on the user-item graph.The decoder digests the refined embeddings to output the prediction score by considering the interactions among user,item,and context embeddings.We conduct experiments on three real-world datasets from Yelp and Amazon,validating the effectiveness of GCM and the benefits of performing graph convolutions for CARS.

Quasi-Situ Characterization of Deformation in Low-Carbon Steel with Equiaxed and Lamellar Microstructure Treated by the Quenching and Partitioning Process

The relationship between microstructure morphology and mechanical properties of the low-carbon steel(Fe-0.20 C-2.59 Mn-2.13 Si)treated by diff erent intercritical annealed quenching and partitioning(Q&P)processes was investigated through interrupted tensile tests plus quasi-situ electron backscatter diff raction measurements.Results show that size and distribution of retained austenite(RA)directly aff ect the sequence of deformation induced martensitic transformation.As strain increases,the equiaxed RA grains wrapped by ferrite transform fi rst,followed by the equiaxed and fi lm-like RA grains adjacent to martensite.Compared with traditional intercritical annealed Q&P steel with equiaxed structure,the steel with quenching pretreatment contains uniform lamellar structure and the relatively fi lm-like type of RA,leading to the higher yield strength,tensile strength,and elongation,as well as the steady increase in dislocation density upon straining.

Intermediate phase-enhanced Ostwald ripening for the elimination of phase segregation in efficient inorganic CsPbIBr_(2)perovskite solar cells

Mixed halide perovskites with the ability to tune bandgaps exhibit attractive applications in tandem solar cells,building integrated photovoltaic and wavelength-tunable light-emitting devices.However,halide demixing under illumination or in the dark with a charge-carrier injection in both hybrid and inorganic perovskites results in bandgap instability and current-density-voltage(J-V)hysteresis,which can significantly hamper their application.Here,we demonstrate that halide segregation and J-V hysteresis in mixed halide inorganic CsPbIBr_(2)solar cells can be effectively mitigated by introducing an intermediate phase-enhanced Ostwald ripening through the control of the chemical composition in the CsPbIBr_(2)precursor solution.Excess amounts of either PbBr_(2)or CsI are incorporated into originally even molar amounts of PbBr_(2)and CsI precursor solutions.With the PbBr_(2)-excess,we observed an enlarged perovskite grain size,no detectable halide phase segregation at the grain boundaries nor the perovskite/TiO2 interface,an increased minority carrier lifetime,a reduced J-V hysteresis,and an improved solar-cell performance.However,different CsI:PbBr_(2)stoichiometric ratios were found to have different effects on the performance of the perovskite solar cell.The excessive lead phase is reactive with the dimethyl sulfoxide(DMSO)in the precursor solution to form the Pb(I,Br)2·DMSO complex and the quasi-twodimensional(2D)CsPb_(2)(I,Br)5,which are conducive to Ostwald maturation and defect extinction.Finally,the CsPbIBr_(2)solar cell with a PbBr_(2)-excess precursor composition reaches a power conversion efficiency(PCE)of 9.37%(stabilized PCE of 8.48%)and a maximum external quantum efficiency of over 90%.

Phase segregation in inorganic mixed-halide perovskites:from phenomena to mechanisms

Halide perovskites,such as methylammonium lead halide perovskites(MAPbX3,X=I,Br,and Cl),are emerging as promising candidates for a wide range of optoelectronic applications,including solar cells,light-emitting diodes,and photodetectors,due to their superior optoelectronic properties.All-inorganic lead halide perovskites CsPbX3 are attracting a lot of attention because replacing the organic cations with Cs+enhances the stability,and its halide-mixing derivatives offer broad bandgap tunability covering nearly the entire visible spectrum.However,there is evidence suggesting that the optical properties of mixed-halide perovskites are influenced by phase segregation under external stimuli,especially illumination,which may negatively impact the performance of optoelectronic devices.It is reported that the mixed-halide perovskites in forms of thin films and nanocrystals are segregated into a low-bandgap I-rich phase and a high-bandgap Br-rich phase.Herein,we present a critical review on the synthesis and basic properties of all-inorganic perovskites,phase-segregation phenomena,plausible mechanisms,and methods to mitigate phase segregation,providing insights on advancing mixed-halide perovskite optoelectronics with reliable performance.

Parity-time-symmetric whispering-gallery mode nanoparticle sensor[Invited]

We present a study of single nanoparticle detection using parity-time （PT） symmetric whispering-gaUery mode （WGM） resonators. Our theoretical model and numerical simulations show that, with balanced gain and loss, the PT-symmetric WGM nanoparticle sensor, tailored to operate at PT phase transition points （also called exceptional points）, exhibits significant enhancement in frequency splitting when compared with a single WGM nanopartide sensor subject to the same perturbation. The presence of gain in the PT-symmetric system leads to narrower linewidth, which helps to resolve smaller changes in frequency splitting and improve the detection limit of nanoparticle sensing. Furthermore, we also provide a general method for detecting multiple nanopartides entering the mode volume of a PT-symmetric WGM sensor one by one. Our study shows the feasibility of PT-symmetric WGM resonators for ultrasensitive single nanoparticle and biomolecule sensing.

Oxygen-deficient bismuth tungstate and bismuth oxide composite photoanode with improved photostability

A homogeneous layer of Bi_2O_3-Bi_(14)WO_(24) composite(BWO/Bi_2O_3) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi14 WO24 component within the Bi_2O_3 layer was found to be important in stabilising the photoelectrochemical performances of Bi_2O_3 photoanode by promoting the photoelectron transport. The unmodified Bi_2O_3 suffered from severe photocorrosion as proven by X-ray diffraction(XRD) and inductively coupled plasma(ICP) analyses while the composite thin film was active without noticeable activity decay for at least 3 h of illumination. This strategy might be applicable to other photocatalysts with stability issues.

Signal-on bimodal sensing glucose based on enzyme product-etching MnO_(2)nanosheets for detachment of MoS_(2)quantum dots

The sensitive and rapid detection of blood glucose is very important for monitoring and managing diabetes.Herein,a fluorescent/magnetic bimodal sensing strategy is proposed for glucose detection using a multifunction-responsive nanocomposite(MoS_(2)QDs-MnO_(2)NS).MoS_(2)QDs act as fluorescent probes,and MnO_(2)nanosheets are used as both quenchers and recognizers in this sensing platform.In the presence of glucose-mediated enzyme product(H_(2)O_(2)),MnO_(2)nanosheet is etched,thus releasing MoS_(2)QDs and Mn^(2+)ions,which causes the significantly enhancement of fluorescent and magnetic signals.Furthermore,MoS_(2)QDs-MnO_(2)NS-based fluorescent test paper is constructed for H_(2)O_(2)sensing with the naked eyes.Under optimal conditions,the dual linear ranges of 20-300μmol/L and 40-250μmol/L toward glucose detection are obtained for the fluorescent and magnetic mode,respectively.Furthermore,this bimodal assay exhibits good reproducibility and acceptable accuracy in glucose detection of clinical samples,demonstrating great versatility and flexibility of multifunctional probes in glucose detection.