Understanding the Pt-like Catalytic Activity of Transition Metal Carbide Ta4C_(3) for I_(3)^(-) Reduction

This paper attempts to understand the Pt-like catalytic activity of transition metal carbide Ta4C_(3) for IRR(I_(3)^(-)reduction reaction)based on the correlation of adsorption energy to d-band center(εd).Ta4C_(3) was prepared by carbothermal reduction method with a template.Its photoelectrochemical properties were investigated as a CE(counter electrode)in DSSC(dye-sensitized solar cell).Its surface electronic structures,including DOS(density of state)andεd,and adsorption energy were computed by first-principle DFT(density functional theory).In TMC(transition metal carbide)Ta4C_(3),the interaction between Ta and C atoms makes the d-band of Ta broaden and results in the downward shift of itsεd.A moderate absorption energy corresponding to theεd is achieved,which is the nature of the Pt-like catalytic activity of Ta4C_(3).Appropriate change of adsorption energy by adjustingεd is a promising strategy to improve catalytic activity.This work is of great significance to the fundamental and application researches.

Frictional sliding of infilled planar granite fracture under oscillating normal stress

This paper investigates the frictional behavior of the infilled rock fracture under dynamic normal stress.A series of direct shear tests were conducted on saw-cut granite fractures infilled with quartz using a selfdeveloped dynamic shear apparatus,and the effects of normal load oscillation amplitude,normal load oscillation period and sliding velocity were studied.The test results reveal that the shear response can be divided into three stages over a whole loading-unloading process,characterized by different time spans and stress variations.Generally,a smaller oscillation amplitude,a longer oscillation period and a fast shear velocity promote the stability of the friction system,which is also confirmed by the Coulomb failure criterion calculated based on the observed periodic apparent friction coefficient.The dynamic strengthening/weakening phenomenon is dependent on the oscillation amplitude and product of sliding velocity and oscillation period(vT).Also,the rate and state friction law incorporating the parameter a that characterizes the normal stress variation is employed to describe the dynamic friction coefficient but exhibits an incompetent performance when handling intensive variation in normal stress.Finally,the potential seismicity induced by oscillating normal stress based on the observed stress drop is analyzed.This work helps us understand the sliding process and stability evolution of natural faults,and its benefits for relative hazard mitigation.

Mechanical behaviour of fiber-reinforced grout in rock bolt reinforcement

Grouted rock bolts subject to axial loading in the field exhibit various failure modes,among which the most predominant one is the bolt-grout interface failure.Thus,mechanical characterization of the grout is essential for understanding its performance in ground support.To date,few studies have been conducted to characterize the mechanical behaviour of fiber-reinforced grout(FRG)in rock bolt reinforcement.Here we experimentally studied the mechanical behaviour of FRG under uniaxial compression,indirect tension,and direct shear loading conditions.We also conducted a series of pullout tests of rebar bolt encapsulated with different grouts including conventional cementitious grout and FRG.FRG was developed using 15%silica fume(SF)replacement of cement(by weight)and steel fiber to achieve highstrength and crack-resistance to overcome drawbacks of the conventional grout.Two types of steel fibers including straight and wavy steel fibers were further added to enhance the grout quality.The effect of fiber shape and fiber volume proportion on the grout mechanical properties were examined.Our experimental results showed that the addition of SF and steel fiber by 1.5%fiber volume proportion could lead to the highest compressive,tensile,and shear strengths of the grout.The minimum volume of fiber that could improve the mechanical properties of grout was found at 0.5%.The scanning electron microscopy(SEM)analysis demonstrated that steel fibers act as an excellent bridge to prevent the cracks from propagating at the interfacial region and hence to aid in maintaining the integrity of the cementitious grout.Our laboratory pullout tests further confirmed that FRG could prevent the cylindrical grout annulus from radial crack and hence improve the rebar’s load carrying capacity.Therefore,FRG has a potential to be utilized in civil and mining applications where high-strength and crack-resistance support is required.

Green High Yield and Efficient Cultivation Technique of Rape for Both Vegetable and Oilseed Utilization

This paper introduces a set of green,high-yield and high-efficiency cultivation technique of rape for both vegetable and oilseed utilization,including selection of suitable varieties and sowing methods,seedling raising,timely transplanting,field management,pest and disease control,timely harvest,drying rapeseed into storage and so on.The technique not only improves the yield of rape,but also enriches the citizens’vegetable basket and farmers’pocketbook.

Decitabine in combination with idarubicin within a modified busulfan/cyclophosphamide conditioning regimen for patients with advanced myelodysplastic syndrome:A prospective multicenter clinical cohort study

To the Editor:Allogeneic hemopoietic stem cell transplantation(allo-HSCT)represents the only long-term survival treatment choice for patients with myelodysplastic syndromes(MDS)and MDS/myeloproliferative neoplasm(MPN).Unfortunately,post-hemopoietic stem cell transplantation(HSCT)relapse remains a cause of treatment failure and the results of salvage treatments are poor.Developing better conditioning regimens is urgently needed.Previous studies have shown synergistic antileukemic effects between decitabine(DEC)and idarubicin(IDA).[1]In an attempt to design a conditioning strategy with very low toxicity but considerable myelosuppressive activity and potential immune-enhancing effects for patients with high-risk MDS and MDS/MPN,we combined DEC and IDA with busulfan,cyclophosphamide,andudarabine for a modied myeloablative regimen in this prospective,multicenter cohort study(hereafter referred to as the“DEC/IDA study”).

Simple real-time high-sensitivity heterodyne coherent optical transceiver at intraplane satellite communication

In this paper,we demonstrate a high-sensitivity and real-time heterodyne coherent optical transceiver for intraplane satellite communication,without digital-to-analog converter(DAC)devices and an optical phase lock loop(OPLL).Based on the scheme,a real-time sensitivity of-49 dBm is achieved at 5 Gbps QPSK.Because DAC is not needed at the transmitter,as well as OPLL at the receiver,this reduces the system cost.Furthermore,the least required Rx ADC bit-width is also discussed.Through theoretical analysis and experimental results,our cost-effective transceiver satisfies the scenario and could be a promising component for future application.

Low dose bisphenol A impairs spermatogenesis by suppressing reproductive hormone production and promoting germ cell apoptosis in adult rats

Bisphenol A （BPA）, an estrogenic chemical, has been shown to reduce sperm count; however, the underlying mechanisms remain unknown. Herein, we show that oral administration of BPA （2 μg/kg） for consecutive 14 days in adult rats （BPA rats） significantly reduced the sperm count and the number of germ cells compared to controls. The serum levels of testosterone and follicle-stimulating hormone （FSH）, as well as the level of GnRH mRNA in BPA rats were lower than those of control rats. Testosterone treatment could partially rescue the reduction of germ cells in BPA rats. Notably, the number of apoptotic germ cells was significantly increased in BPA rats, which was insensitive to testosterone. Furthermore, the levels of Fas, FasL and caspase-3 mRNA in the testicle of BPA rats were increased in comparison with controls. These results indicate that exposure to a low dose of BPA impairs spermatogenesis through decreasing reproductive hormones and activating the Fas/FasL signaling pathway.

Heteroatom-doped porous carbon from methyl orange dye wastewater for oxygen reduction

Banana peel-derived porous carbon(BPPC) was prepared from banana peel and used as an adsorbent for methyl orange(MO) wastewater removal. BPPC-MO50 is a N,S-doped BPPC obtained via secondary carbonization. The BPPC-MO50 exhibited a high specific surface area of1774.3 m^2/g. Heteroatom-doped porous carbon(PC) was successfully synthesized from the BPPC absorbed MO at high temperature and used for oxygen reduction. The BPPC-MO50 displayed the highest ORR onset potential among all carbon-based electrocatalysts, i.e., 0.93 V vs.reversible hydrogen electrode(RHE). This is the first report to describe porous carbon-activated materials from agriculture and forestry waste that is used for adsorption of dyes from wastewater via an enhanced heteroatom(N,S) content. These results may contribute to the sustainable development of dye wastewater treatment by transforming saturated PC into an effective material and has potential applications in fuel cells or as energy sources.

Prevalence and risk factors of prolonged grief disorder among bereaved survivors seven years after the Wenchuan earthquake in China: A cross-sectional study

Background:This study aimed to determine the prevalence and predictive factors of prolonged grief disorder(PGD)among those bereaved by the Wenchuan earthquake in Southwestern China seven years after the event.Methods:A cross-sectional survey based on census tracts was conducted on the bereaved earthquake survivors.Responses to the questionnaire regarding PGD and its potential associated factors were obtained either through face-to-face or telephone interview.PGD was screened by a validated Chinese version of the PGD questionnaire-13(PG-13).Bivariate and multivariate regression analyses were used to determine the prevalence and associated risk factors of PGD.Results:A total of 1464 bereaved earthquake survivors,with a response rate of 97.6%,were included in the study.Of the 1464 respondents studied,124(8.47%)were diagnosed with PGD.Multivariate regression analysis demonstrated that PGD in the bereaved earthquake individuals was significantly associated with several factors,including age,economic burden,close kinship with the deceased,and living with the deceased before the loss.Wenchuan earthquake bereaved aged 41e60 years were more likely to develop PGD compared to those aged younger than 40 or older than 60(OR=2.075,95%CI=1.297e3.319).Those who had a close kinship with the deceased had a higher tendency to develop PGD(OR=5.144,95%CI=2.716e9.740).The odds of PGD among the earthquake bereaved with economic burdens were higher relative to those who did not experience an economic burden(OR=8.123,95%CI=2.657e24.831).Those who living with the deceased before loss also had a higher tendency to develop PGD(OR=0.179,95%CI=0.053e0.602).Conclusions:This study revealed that a significantly high proportion(8.47%)of the Wenchuan earthquake-bereaved remain grieving seven years after the event.Those diagnosed with PGD should receive appropriate interventions from clinical psychologists.The risk factors identified in this study are crucial for the early screening and prevention of PGD in future nursing and psycho-clinical practices.

Home Planting Techniques of Green and Healthy Rape Sprouts

With the continuous development of society and the continuous improvement of people s income levels,consumers demand for agricultural products has also changed.Rape sprouts as a new type of green and pollution-free health food meet people s needs.In this paper,we summarized a set of home cultivation techniques for green and healthy rape sprouts.The techniques are simple to operate and low in cost.Growers can notonly experience the fun of planting and but also taste green and healthy food.

Microcrack fracturing of coal specimens under quasi-static combined compression-shear loading

Coal pillars are usually loaded under combined compression-shear stresses at underground coal mines.Their long-term stability is critical to the utilization of underground structures,such as underground reservoirs at coal mines.In this study,a modified rock property testing system was used to explore the mechanical properties of coal specimens under quasi-static combined compression-shear loading conditions.The acoustic emission technique was applied to investigating the microcrack fracturing of coal specimens at various inclination angles.The experimental results show that specimen inclination has remarkable effects on the microcrack initiation,microcrack damage and ultimate failure of the coal specimen.The failure mode of the coal specimen tends to transit from axial splitting to shear failure with increasing specimen inclination,and its peak strength is closely associated with the microcrack damage threshold.In practice,it is recommended to consider coal strength under combined compression-shear loading when using empirical pillar strength formulae so that the effect of pillar inclination can be included.

Faulty Feeder Identification and Fault Area Localization in Resonant Grounding System Based on Wavelet Packet and Bayesian Classifier

Accurate fault area localization is a challenging problem in resonant grounding systems(RGSs).Accordingly,this paper proposes a novel two-stage localization method for single-phase earth faults in RGSs.Firstly,a faulty feeder identification algorithm based on a Bayesian classifier is proposed.Three characteristic parameters of the RGS(the energy ratio,impedance factor,and energy spectrum entropy)are calculated based on the zero-sequence current(ZSC)of each feeder using wavelet packet transformations.Then,the values of three parameters are sent to a pre-trained Bayesian classifier to recognize the exact fault mode.With this result,the faulty feeder can be finally identified.To find the exact fault area on the faulty feeder,a localization method based on the similarity comparison of dominant frequency-band waveforms is proposed in an RGS equipped with feeder terminal units(FTUs).The FTUs can provide the information on the ZSC at their locations.Through wavelet-packet transformation,ZSC dominant frequency-band waveforms can be obtained at all FTU points.Similarities of the waveforms of characteristics at all FTU points are calculated and compared.The neighboring FTU points with the maximum diversity are the faulty sections finally determined.The proposed method exhibits higher accuracy in both faulty feeder identification and fault area localization compared to the previous methods.Finally,the effectiveness of the proposed method is validated by comparing simulation and experimental results.

Recent advances of two-dimensional materials in smart drug delivery nanosystems

Smart drug delivery nano-systems show significant changes in their physical or chemical properties in response to slight change in environmental physical and/or chemical signals,and further releasing drugs adjusted to the progression of the disease at the right target and rate intelligently.Two-dimensional materials possess dramatic status extend all over various scientific and technological disciplines by reason of their exceptional unique properties in application of smart drug delivery nano-systems.In this review,we summarized current progress to highlight various kinds of two-dimensional materials drug carriers which are widely explored in smart drug delivery systems as well as classification of stimuli responsive two-dimensional materials and the advantages and disadvantages of their applications.Consequently,we anticipate that this review might inspire the development of new two-dimensional materials with smart drug delivery systems,and deepen researchers’understanding of smart nano-carries based on two-dimensional materials.

Thin,soft,skin-integrated electronics for real-time and wireless detectionof uricacid in sweat

Wearable sweat sensors are gaining significant attention due to their unparalleled potential for noninvasive health monitoring.Sweat,as a kind of body fluid,contains informative physiological indicators that are related to personalized health status.Advances in wearable sweat sampling and routing technologies,flexible,and stretchable materials,and wireless digital technologies have led to the development of integrated sweat sensors that are comfortable,flexible,light,and intelligent.Herein,we report a flexible and integrated wearable device via incorporating a microfluidic system and a sensing chip with skin-integrated electronic format toward in-situ monitoring of uric acid(UA)in sweat that associates with gout,cardiovascular,and renal diseases.The microfluidic system validly realizes the real-time capture perspiration from human skin.The obtained detection range is 5-200μM and the detection limit is 1.79μM,which offers an importance diagnostic method for clinical relevant lab test.The soft and flexible features of the constructed device allows it to be mounted onto nearly anywhere on the body.We tested the sweat UA in diverse subjects and various body locations during exercise,and similar trends were also observed by using a commercial UA assay kit.

Stretchable,skin-conformable neuromorphic system for tactile sensory recognizing and encoding

Expanding wearable technologies to artificial tactile perception will be of significance for intelligent human-machine interface,as neuromorphic sensing devices are promising candidates due to their low energy consumption and highly effective operating properties.Skin-compatible and conformable features are required for the purpose of realizing wearable artificial tactile perception.Here,we report an intrinsically stretchable,skin-integrated neuromorphic system with triboelectric nanogenerators as tactile sensing and organic electrochemical transistors as information processing.The integrated system provides desired sensing,synaptic,and mechanical characteristics,such as sensitive response(~0.04 kPa^(-1))to low-pressure,short-and long-term synaptic plasticity,great switching endurance(>10000 pulses),symmetric weight update,together with high stretchability of 100%strain.With neural encoding,demonstrations are capable of recognizing,extracting,and encoding features of tactile information.This work provides a feasible approach to wearable,skin-conformable neuromorphic sensing system with great application prospects in intelligent robotics and replacement prosthetics.

Comparative study on heat extraction performance of three enhanced geothermal systems

Enhanced geothermal systems(EGSs)in this study are classified as fracturing-EGS(F-EGS),pipe-EGS(P-EGS)and excavation-EGS(E-EGS)according to reservoir stimulation strategies.However,the heat extraction performances of three EGSs employing different stimulation strategies are not fully understood.Here,we define the region where the pore pressure increment calculated by a hydraulic fracturing process is higher than rock tensile strength as the stimulation region for establishing a more accurate F-EGS model,and then compare three geothermal systems to select a appropriate reservoir stimulation strategy.We find that the F-EGS model assuming an entire stimulated region significantly exaggerates the heat extraction results.The optimal conditions for P-EGS are low injection rates and short operation times,which is suiTablefor seasonal heating or multi-energy co-generation projects including a thermal recovery phase.Theoretically,E-EGS has better geothermal extraction performance than F-EGS based on existing model assumptions,but its construction feasibility and economics need further exploration.H2O is more suiTableas a heat exchange fluid in E-EGS than supercritical CO_(2).This study provides a reference for geothermal mining simulation and reservoir stimulation strategy selection.

Versatile Ti_(3)C_(2)T_(x)MXene for free-radical scavenging

MXene,as an emerging two-dimensional(2D)material with ultrathin structure and fascinating physiochemical properties,has been widely explored in broad applications.Versatile functions of MXenes are continuously explored.This work presents distinctive feature of MXene-Ti_(3)C_(2)T_(x)nanosheets for free-radical(FRs)scavenging that never reported before.We demonstrated the mechanism and equation in regard to the reaction between Ti_(3)C_(2)T_(x)and H_(2)O_(2),which was applied to design colorimetric H_(2)O_(2)strip assay with good performance.The good FRs scavenging capability of Ti_(3)C_(2)T_(x),including a series of reactive oxygen species(ROS)and reactive nitrogen species(RNS),was systemically confirmed.The antioxidation capability of Ti_(3)C_(2)T_(x)for protecting cells from oxidative damage was demonstrated using the oxidative damage model of alpha mouse liver 12(AML-12)cells.This original work provides huge opportunities for MXenes in FR-related biomedical applications.

Paper-Based Electrochemical Biosensors for Point-of-Care Testing of Neurotransmitters

Abstract Neurotransmitters are important biological molecules related to several nervous system diseases(NSDs).Point-of-care test-ing(POCT)of neurotransmitters is of great importance in preclinical research and early diagnosis of NSDs.Among various POCT platforms,paper-based electrochemical biosensors have achieved great advances in detection of neurotransmitters,thus taking a significant role in POCT of neurotransmitters nowadays.This review gives an overview of the recent advances of paper-based electrochemical biosensors for POCT of neurotransmitters.We first introduce the types of neurotransmitters and biological sample sources mainly used for neurotransmitter detection.Second,we review the components and the traditional fabrication technologies for paper-based electrochemical POCT biosensors,and then the functional modification methods of biosensor surfaces and three-dimensional fabrication methods for further enhancement of their detection performance.Then,we list examples of paper-based electrochemical biosensors used for detecting different neurotransmitters in biologi-cal samples.Last,we give a conclusion and promising development direction of paper-based electrochemical biosensors for neurotransmitters detection.The purpose of this review is to introduce the paper-based electrochemical biosensors as an emerging technology for POCT of neurotransmitters,offering a reference for readers and researchers for early diagnosis of NSDs using POCT technologies.

Flexible sensors based on assembled carbon nanotubes

Flexible sensors have attracted significant attention as they could be directly attached to/implanted into the body or incorporated into textiles to monitor human activities and give feedbacks for healthcare.A typical fabrication method is the direct use of intrinsically flexible active materials such as carbon nanotubes(CNTs).CNTs are generally assembled into aligned structures to extend their remarkable chemical,mechanical,and electrical properties to macroscopic scale to afford high sensing performances.In this review,we present the recent advance of CNT assemblies as electrodes or functional materials for flexible sensors.The realizations of aligned CNTs are firstly investigated.A variety of flexible sensors based on the aligned CNTs are then carefully explored,with an emphasis on understanding the working mechanism for their high sensing properties.The main attention is later paid to comparing two main categories of flexible sensors with fiber and film shapes.The remaining challenges are finally highlighted to offer some insights for future study.