Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.

Main focus of parents of children with attention deficit hyperactivity disorder and the effectiveness of early clinical screening

BACKGROUND Attention deficit hyperactivity disorder(ADHD)is a common mental and behavioral disorder among children.AIM To explore the focus of attention deficit hyperactivity disorder parents and the effectiveness of early clinical screening METHODS This study found that the main directions of parents seeking medical help were short attention time for children under 7 years old(16.6%)and poor academic performance for children over 7 years old(12.1%).We employed a two-stage experiment to diagnose ADHD.Among the 5683 children evaluated from 2018 to 2021,360 met the DSM-5 criteria.Those diagnosed with ADHD underwent assessments for letter,number,and figure attention.Following the exclusion of ADHD-H diagnoses,the detection rate rose to 96.0%,with 310 out of 323 cases identified.RESULTS This study yielded insights into the primary concerns of parents regarding their children's symptoms and validated the efficacy of a straightforward diagnostic test,offering valuable guidance for directing ADHD treatment,facilitating early detection,and enabling timely intervention.Our research delved into the predominant worries of parents across various age groups.Furthermore,we showcased the precision of the simple exclusion experiment in discerning between ADHD-I and ADHD-C in children.CONCLUSION Our study will help diagnose and guide future treatment directions for ADHD.

Back-n white neutron source at CSNS and its applications

Back-streaming neutrons from the spallation target of the China Spallation Neutron Source(CSNS)that emit through the incoming proton channel were exploited to build a white neutron beam facility(the so-called Back-n white neutron source),which was completed in March 2018.The Back-n neutron beam is very intense,at approximately 29107 n/cm2/s at 55 m from the target,and has a nominal proton beam with a power of 100 kW in the CSNS-I phase and a kinetic energy of 1.6 GeV and a thick tungsten target in multiple slices with modest moderation from the cooling water through the slices.In addition,the excellent energy spectrum spanning from 0.5 eV to 200 MeV,and a good time resolution related tothe time-of-flight measurements make it a typical white neutron source for nuclear data measurements;its overall performance is among that of the best white neutron sources in the world.Equipped with advanced spectrometers,detectors,and application utilities,the Back-n facility can serve wide applications,with a focus on neutron-induced cross-sectional measurements.This article presents an overview of the neutron beam characteristics,the experimental setups,and the ongoing applications at Backn.

Measurement of the ^(232)Th(n,f)cross section in the 1-200 MeV range at the CSNS Back-n

The ^(232)Th(n,f)cross section is very important in basic nuclear physics and applications based on the Th/U fuel cycle.Using the time-of-flight method and a multi-cell fast-fission ionization chamber,a novel measurement of the^(232)Th(n,f)cross sec-tion relative to^(235)U in the 1–200 MeV range was performed at the China Spallation Neutron Source Back-n white neutron source(Back-n).The fission event-neutron energy spectra of^(232)Th and^(235)U fission cells were measured in the single-bunch mode.Corrected 232Th/235U fission cross-sectional ratios were obtained,and the measurement uncertainties were 2.5–3.7%for energies in the 2–20 MeV range and 3.6–6.2%for energies in the 20–200 MeV range.The^(232)Th(n,f)cross section was obtained by introducing the standard cross section of^(235)U(n,f).The results were compared with those of previous theoreti-cal calculations,measurements,and evaluations.The measured 232Th fission cross section agreed with the main evaluation results in terms of the experimental uncertainty,and 232Th fission resonances were observed in the 1–3 MeV range.The present results provide^(232)Th(n,f)cross-sectional data for the evaluation and design of Th/U cycle nuclear systems.

Improving efficiency of inverted perovskite solar cells via ethanolamine-doped PEDOT:PSS as hole transport layer

In order to fabricate high-performance inverted perovskite solar cells(Pe SCs), an appropriate hole transport layer(HTL) is essential since it will affect the hole extraction at perovskite/HTL interface and determine the crystallization quality of the subsequent perovskite films. Herein, a facile and simple method is developed by adding ethanolamine(ETA)into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) as HTL. The doping of a low-concentration ETA can efficiently modify the electrical properties of the PEDOT:PSS film and lower the highest occupied molecular orbital(HOMO) level, which is more suitable for the hole extraction from the perovskite to HTL. Besides, ETA-doped PEDOT:PSS will create a perovskite film with larger grain size and higher crystallinity. Hence, the results show that the open-circuit voltage of the device increases from 0.99 V to 1.06 V, and the corresponding power conversion efficiency(PCE)increases from 14.68% to 19.16%. The alkaline nature of ethanolamine greatly neutralizes the acidity of PEDOT:PSS, and plays a role in protecting the anode, leading the stability of the devices to be improved significantly. After being stored for2000 h, the PCE of ETA-doped PEDOT:PSS devices can maintain 84.2% of the initial value, which is much higher than67.1% of undoped devices.

Biosafety of a 3D-printed intraocular lens made of a poly (acrylamide-co-sodium acrylate) hydrogel in vitro and in vivo

AIM:To assess the biosafety of a poly(acrylamide-cosodium acrylate)hydrogel(PAH)as a 3D-printed intraocular lens(IOL)material.METHODS:The biosafety of PAH was first evaluated in vitro using human lens epithelial cells(LECs)and the ARPE19 cell line,and a cell counting kit-8(CCK-8)assay was performed to investigate alterations in cell proliferation.A thin film of PAH and a conventional IOL were intraocularly implanted into the eyes of New Zealand white rabbits respectively,and a sham surgery served as control group.The anterior segment photographs,intraocular pressure(IOP),blood parameters and electroretinograms(ERG)were recorded.Inflammatory cytokines in the aqueous humor,such as TNFαand IL-8,were examined by ELISA.Cell apoptosis of the retina was investigated by TUNEL assay,and macro PAHge activation was detected by immunostaining.RESULTS:PAH did not slow cell proliferation when cocultured with human LECs or ARPE19 cells.The implantation of a thin film of a 3 D-printed IOL composed of PAH did not affect the IOP,blood parameters,ERG or optical structure in any of the three experimental groups(n=3 for each).Both TNFαand IL-8 in the aqueous humor of PAH group were transiently elevated 1 wk post-operation and recovered to normal levels at 1 and 3 mo post-operation.Iba1+macroPAHges in the anterior chamber angle in PAH group were increased markedly compared to those of the control group;however,there was no significant difference compared to those in the IOL group.CONCLUSION:PAH is a safe material for 3D printing of personal IOLs that hold great potential for future clinical applications.

Improving efficiency of n–i–p perovskite solar cells enabled by 3-carboxyphenylboronic acid additive

In the past period of time, perovskite solar cells have gained tremendous developments in improving photovoltaic performance, but they still face severe challenges. Defects in perovskite layers, especially at grain boundaries, severely limit the stabilization and efficiency of solar cells. In this work, we adopt 3-carboxyphenylboronic acid(CPBA) for modifying defects in perovskite thin films. Through the interaction among the carboxyl group, boronic acid and lead ions in the perovskite film, the crystallization effect of the perovskite molecular is greatly optimized. Moreover, the film defects are spontaneously passivated and the band gap is reduced, increasing the open circuit voltage and fill factor. Therefore,power conversion efficiency has been increased from 17.25% to 20.20%. This discovery provides a potential strategy for passivating the trap states in perovskite and enhancing the properties of devices.

An-Luo-Hua-Xian Pill Improves the Regression of Liver Fibrosis in Chronic Hepatitis B Patients Treated with Entecavir

Background and Aims:Chronic hepatitis B(CHB)can cause liver fibrosis and lead to cirrhosis and cancer.As the effectiveness of antiviral therapy to reverse liver fibrosis is limited,We aimed to evaluate the effect of An-Luo-Hua-Xian pill(ALHX)on fibrosis regression in CHB patients treated with entecavir(ETV).Methods:Treatment-naïve patients with CHB were randomly treated with ETV alone or combined with ALHX(ETV+ALHX)between October 1,2013 and December 31,2020.Demographic,laboratory,and liver histology data before and after 78 weeks of treatment were collected.The Ishak fibrosis score(F)was used and fibrosis regression required a decrease in F of≥1 after treatment.Results:A total of 780 patients were enrolled,and 394 with a second liver biopsy after treatment were included in the per-protocol population,132 in ETV group and 262 in ETV+ALHX group.After 78 weeks of treatment,the fibrosis regression rate in the ETV+ALHX group was significantly higher than that of the ETV group at baseline F≥3 patients:124/211(58.8%)vs.45/98(45.9%),p=0.035.The percentage of patients with a decreased liver stiffness measurement(LSM)was higher in the ETV+ALHX group:156/211(73.9%)vs.62/98(63.%),p=0.056.Logistic regression analysis showed that ETV combined with ALHX was associated with fibrosis regression[odds ratio(OR)=1.94,p=0.018],and a family history of hepatocellular carcinoma was on the contrary.(OR=0.41,p=0.031).Conclusions:ETV combined with ALHX increased liver fibrosis regression in CHB patients.

Synthesis of gold nanocubes/PEI-wrinkled CoSe_(2) nanomaterials and its application in electrochemical immunosensors for detection of dipropyl phthalate

CoSe_(2) nanosheet materials with a wrinkled sheet structure and large surface area were synthesized via a simple hydrothermal method.Then polyethyleneimine(PEI)was used to functionalize wrinkled CoSe_(2)(w-CoSe_(2))to make gold nanocubes(AuNCs)uniformly anchored onto the surface of PEI-w-CoSe_(2) via Au-N bonds.And its application in electrochemical immunosensors for the detection of dipropyl phthalate(DPrP)was studied.The obtained material was characterized by the Fourier transform infrared spectroscopy(FTIR),transmission electron microscope(TEM),energydispersive spectroscopy(EDS),X-ray diffraction(XRD)and Raman spectroscopy.The effective surface area and conductivity of the electrode were enhanced by the introduction of AuNCs/PEI-w-CoSe_(2) nanocomposite.Cyclic voltammetry(CV),differential pulse voltammetry(DPV)and electrochemical impedance spectroscopy(EIS)were used to characterize the performance of immunosensor.After DPrP binds to antibodies via the antigen-antibody interaction,[Fe(CN)6]3-/4-was used as a signal probe to monitor the change of oxidation current of different DPrP concentrations.Under optimal conditions,the electrochemical responses of the prepared immunosensor were linear when the DPrP concentrations ranged from 1×10^(-11) to 1×10^(-5) mol·L-1,with a detection limit of 1.39×10^(-12) mol·L^(-1).The coefficient of determination(R2)is 0.995,indicating that the degree of fitting is good.Besides,the constructed immunosensor exhibited acceptable reproducibility,selectivity,and stability.Therefore,it may be found that the composite material has good application prospects in the electrochemical sensors field.

Significant Histologic Changes Are Not Rare in Treatment-naive Hepatitis B Patients with Normal Alanine Aminotransferase Level:A Meta-analysis

Background and Aims:Chronic hepatitis B is the main cause of liver cancer.However,the most neglected group has been treatment-naive chronic hepatitis B patients with normal alanine aminotransferase(ALT).People have tended to subjectively assume that the liver lesions of these patients are not serious and do not need antiviral treatment.However,the truth is not as optimistic as we thought.We aimed in this study to analyze the proportion of significant inflammation or fibrosis in aforementioned patients.Methods:Medline,Embase,and Cochrane Library were searched up to January 10th 2020,to identify studies of these patients with liver biopsy.The double arcsine method was used with a random-effect model to combine the proportion of significant inflammation or fibrosis.Potential heterogeneity was explored by subgroup analysis and meta-regression.Outcome of interests included the proportion of significant inflammation or fibrosis and cirrhosis.The secondary outcome was to find the risk factors of significant histological changes.Results:Nineteen eligible studies,with 2,771 participants,were included.The pooled proportion of significant inflammation or fibrosis was 35%[95%confidence interval(CI):27 to 43]and 30%(95%CI:25 to 36),respectively.The pooled proportion of cirrhosis was 3%[95%CI:1 to 5,(12 studies;1,755 participants)].In subgroup analysis,old age[vs.young(<40 years-old),44%vs.26%,p=0.012]was significantly associated with higher fibrosis stage as well as cirrhosis[vs.young(<40 years-old),4.8%vs.1.8%,p<0.001].Conclusions:About 1/3 of the treatment-naive chronic hepatitis B patients with normal ALT show significant histological changes,and some even have cirrhosis.

The relationship between SARS-COV-2 RNA positive duration and the risk of recurrent positive

Background:The management of discharge COVID-19 patients with recurrent positive SARS-CoV-2 RNA is challenging.However,there are fewer scientific dissertations about the risk of recurrent positive.The aim of this study was to explore the relationship between SARS-COV-2 RNA positive duration(SPD)and the risk of recurrent positive.