Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

The large-scale modular BGO detection array(LAMBDA)design and test

Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS detector,the large-scale modular BGO detection array(LAMBDA),tailored for measuringβ-decay intensity distributions of fission products.The modular design allows the LAMBDA detectors to be assembled in various configurations.The final version of LAMBDA consists of 102 identical 60 mm×60 mm×120 mm BGO crystals and exhibits a high full-energy peak efficiency exceeding 80%at 0.5∼8 MeV based on a Monte Carlo simulation.Currently,approximately half of the LAMBDA modules have been manufactured.Tests usingγ-ray sources and nuclear reactions demonstrated favorable energy resolution,energy linearity,and efficiency uniformity across the modules.Forty-eight modules have been integrated into the prototype LAMBDA-I.The capability of LAMBDA-I inβ-delayed-decay experiments was evaluated by commissioning measurements using the ^(152)Eu source.

Novel thick-target inverse kinematics method for the astrophysical ^(12)C+^(12)C fusion reaction

The ^(12)C+^(12)C fusion is one of the most important reactions in modern nuclear astrophysics.The trend and magnitude of the reaction rate within the Gamow window strongly influence various astrophysical processes.However,direct measurement of this reaction is extremely difficult,which makes it necessary to develop indirect methods.In this study,the ^(23)Na+p reaction system was used to study the compound nucleus ^(24)Mg.We employed a thick-target inverse kinematics method combined with the-charged-particle coincidence technique to measure the proton andexit channels of ^(24)Mg.Technical details of the ^(23)Na+p thick-target inverse kinematics experiment and analysis are presented herein.

Numerical simulation of tritium behavior under a postulated accident condition for CFETR TEP system

China Fusion Engineering Test Reactor(CFETR)is China's self-designed and ongoing next-generation fusion reactor project.Tritium confinement systems in CFETR guarantee that the radiation level remains below the safety limit during tritium handling and operation in the fuel cycle system.Our tritium technology team is responsible for studying tritium transport behavior in the CFETR tritium safety confinement systems of the National Key R&D Program of China launched in 2017,and we are conducting CFETR tritium plant safety analysis by using CFD software.In this paper,the tritium migration and removal behavior were studied under a postulated accident condition for the Tokamak Exhaust Processing system of CFETR.The quantitative results of the transport behavior of tritium in the process room and glove box during the whole accident sequence(e.g.,tritium release,alarm,isolation,and tritium removal)have been presented.The results support the detailed design and engineering demonstration-related research of CFETR tritium plant.

内镜下放置金属夹后长期存留在消化道对人体的影响

目的探讨内镜下放置金属夹后长期存留在消化道对人体的影响。方法收集2016年1月-2018年3月该院内镜中心在内镜诊疗中发现消化道有金属夹存留1个月以上的46例患者资料。结果存留时间1个月~5年,平均存留(7.0±0.4)个月。上消化道存留25例,大肠存留21例,共46例,同期使用金属夹的患者共1 498例,占3.1%。上消化道金属夹氧化(锈蚀)8例,占32.0%,大肠存留的金属夹有1枚部分氧化,占4.8%;局部有炎症改变的25例;存留1枚的40例,存留2枚的5例,存留3枚的1例;1例直肠息肉钳除后11个月复查结肠镜发现原部位存留1枚钛夹,并出现1枚新的息肉,病理结果示增生性息肉,局部有明显慢性肉芽肿性炎症改变的13例,占28.3%。上消化道金属夹存留者17例有腹痛症状,占37.0%,大肠金属夹存留患者腹痛1例,占2.2%,腹泻3例,占6.5%。结论金属夹长期存留在消化道有可能导致局部炎症改变及炎性息肉形成,也可引起腹痛、腹泻症状,酸性环境对金属夹有明显氧化(锈蚀)作用,可能诱发毒性反应,应引起内镜及临床医师高度重视。

The clinical features, therapeutic responses, and prognosis of the patients with mantle cell lymphoma

Mantle cell lymphoma(MCL), a special type of non-Hodgkin's lymphoma, is incurable through conventional treatment. This study aimed to analyze the clinical features, therapeutic responses, and prognosis of patients with MCL. Clinical data of 30 patients with MCL treated in our hospital between April 2006 and July 2011 were analyzed. Eighteen patients were treated with CHOP plus rituximab (R-CHOP) regimen, 12 underwent conventional chemotherapy. The median age of the 30 patients was 58 years, 23 were men, all patients had Cyclin D1 overexpression, 29 (96.7%) had advanced disease, 11 (36.7%) had bone marrow involvement, 9 (30.0%) had gastrointestinal involvement, and 15 (50.0%) had splenomegaly. The complete response(CR) rate and overall response rate(ORR) were significantly higher in patients undergoing R-CHOP immunochemotherapy than in those undergoing conventional chemotherapy (38.9% vs. 16.7%, P = 0.187; 72.2% vs. 41.4%, P = 0.098). The difference of 2-year overall survival rate between the two groups was not significant (P = 0.807) due to the short follow-up time. The 2-year progression-free survival (PFS) rate was higher in R-CHOP group than in conventional chemotherapy group (53% vs. 25%, P = 0.083), and was higher in patients with a lower mantle cell lymphoma international prognostic index (MIPI) (51% for MIPI 0-3, 33% for MIPI 4-5, and 0% for MIPI 6-11, P = 0.059). Most patients with MCL were elderly; in an advanced stage; showed a male predominance; and usually had bone marrow involvement, gastrointestinal involvement, or splenomegaly. R-CHOP regimen could improve the CR rate and ORR of MCL patients. MIPI can be a new prognostic index for predicting the prognosis of advanced MCL.

First proof-of-principle experiment with the post-accelerated isotope separator on-line beam at BRIF:measurement of the angular distribution of ^(23)Na+^(40)Ca elastic scattering

The reaction dynamics of exotic nuclei near the drip line is one of the main research topics of current interest.Elastic scattering is a useful probe for investigating the size and surface diffuseness of exotic nuclei.The development of rare isotope accelerators offers opportunities for such studies.To date,many relevant measurements have been performed at accelerators using the projectile fragmentation technique,while the measurements at accelerators using isotope separator on-line(ISOL)systems are still quite scarce.In this work,we present the first proof-of-principle experiment with a post-accelerated ISOL beam at the Beijing Radioactive Ion Beam Facility(BRIF)by measuring the angular distribution of elastic scattering for the stable nucleus^(23)Na from the doubly magic nucleus^(40)Ca at energies above the Coulomb barrier.The angular distribution measured by a silicon strip detector array in a scattering chamber using the ISOL beam at BRIF is in good agreement with that measured by the high-precision Q3 D magnetic spectrograph using the nonISOL beam at nearly the same energy.This work provides useful background for making BRIF a powerful tool for the investigation of the reaction dynamics of exotic nuclei.

Recovery of copper from copper slag using a microbial fuel cell and characterization of its electrogenesis

The microbial fuel cell, which can convert the chemical energy of organic matter into electricity via the catalytic action of microorganisms, is a novel environmentally friendly technology for wastewater treatment and energy generation. The electrical energy generated by the microbial fuel cell can be used as an alternative to a traditional external power source required to extract copper via electrolytic treatment. A dual-chamber microbial fuel cell(DMFC) for the treatment of copper slag sulfuric acid leach liquor was constructed. The electrogenesis performance of the DMFC and its ability to extract copper from the copper slag leachate were investigated. The results demonstrated that the maximum voltage was 540 mV when the DMFC achieved steady-state operation. The removal rate of copper ions was greater than 80.0%, and the maximum value was 92.1%. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the cathodal products. The results showed that the product deposited onto the cathode was copper and that its morphology was similar to that of the electrolytic copper powder. The DMFC can generate electricity and recover copper from copper slag simultaneously.

Diagnostic significance of TCR gene clonal rearrangement analysis in early mycosis fungoides

Mycosis fungoides(MF),the most common type of cutaneous T-cell lymphoma,has various unspecific clinical and histological characteristics.Its early diagnosis is challenging.The application of T-cell receptor(TCR) gene clonal rearrangement to the diagnosis of MF has been widely studied.In this study,we used polymerase chain reaction(PCR) to investigate the diagnostic significance of detecting TCR-γ and-β gene clonal rearrangement in the early diagnosis of mycosis fungoides.PCR for TCR-γ and TCR-β gene rearrangement was performed on 19 patients with suspected early MF,6 with typical MF,and 6 with chronic dermatitis.Of the 19 patients with suspected early MF,13 had TCR-γ gene clonal rearrangement,whereas none had TCR-β gene clonal rearrangement.All patients with typical MF had TCR gene clonal rearrangement,in which 4 showed TCR-γ clonal rearrangement,1 showed TCR-β gene clonal rearrangements,and 1 showed both.No patients with chronic dermatitis had TCR gene clonal rearrangement.These results indicate that TCR gene clonal rearrangement analysis is a useful tool in diagnosing early MF.TCR-γ gene is recommended to the routine analysis,whereas TCR-β gene has potential in combination toward intractable cases.

Hepatitis B surface antigen seroconversion after HBV reactivation in non-Hodgkin's lymphoma

Reactivation of hepatitis B virus(HBV)can occur in lymphoma patients infected with HBV when they receive chemotherapy or immunotherapy.Prophylactic administration of lamivudine(LAM)reduces the morbidity and mortality associated with HBV reactivation.However,what defines HBV reactivation and the optimal duration of treatment with LAM have not yet been clearly established.HBV reactivation may occur due to the cessation of prophylactic LAM,although re-treatment with nucleoside analogs may sometimes result in hepatitis B surface antigen(HBsAg)seroconversion,which is a satisfactory endpoint for the management of HBV infection.We report a case of HBV reactivation in a 68-year-old HBsAg-positive patient who received rituximab-based immunochemotherapy for follicular lymphoma.HBV reactivation developed following cessation of prophylactic LAM therapy.The patient subsequently received treatment with entecavir(ETV),which led to a rapid and sustained suppression of HBV replication and HBsAg seroconversion.We also appraised the literature concerning HBV reactivation and the role of ETV in the management of HBV reactivation in lymphoma patients.A total of 28 cases of HBV reactivation have been reported as having been treated with ETV during or after immunosuppressive chemotherapy in lymphoma patients.We conclude that ETV is an efficacious and safe treatment for HBV reactivation following LAM cessation in lymphoma patients treated with rituximab-based immunochemotherapy.

Relapsed/refractory classical Hodgkin lymphoma effectively treated with low-dose decitabine plus tislelizumab:A case report

BACKGROUND Academic studies have proved that anti-programmed death-1(PD-1)monoclonal antibodies demonstrated remarkable activity in relapsed/refractory classical Hodgkin lymphoma(cHL).However,most patients ultimately experienced failure or resistance.It is urgent and necessary to develop a novel strategy for relapsed/refractory cHL.The aim of this case report is to evaluate the combination approach of low-dose decitabine plus a PD-1 inhibitor in relapsed/refractory cHL patients with prior PD-1 inhibitor exposure.CASE SUMMARY The patient was a 27-year-old man who complained of enlarged right-sided cervical lymph nodes and progressive pain aggravation of the right shoulder over the past 3 mo before admission.Histological analysis of lymph node biopsy was suggestive of cHL.The patient experienced failure of eight lines of therapy,including multiple cycles of chemotherapy,PD-1 blockade,and anti-CD47 antibody therapy.Contrast-enhanced CT showed that the tumors of the chest and abdomen significantly shrunk or disappeared after three cycles of treatment with decitabine plus tislelizumab.The patient had been followed for 11.5 mo until March 2,2021,and no progressive enlargement of the tumor was observed.CONCLUSION The strategy of combining low-dose decitabine with tislelizumab could reverse the resistance to PD-1 inhibitors in patients with heavily pretreated relapsed/refractory cHL.The therapeutic effect of this strategy needs to be further assessed.

Secondary lymphoma develops in the setting of heart failure when treating breast cancer: A case report

BACKGROUND Cardiovascular side effects occur frequently during anti-cancer treatment, and there is a growing concern that they may lead to premature morbidity and death. CASE SUMMARY A 32-year-old woman was diagnosed with breast cancer. After comprehensive treatment with neoadjuvant chemotherapy, surgery, postoperative adjuvant chemotherapy, postoperative adjuvant radiotherapy, and endocrine therapy, her breast cancer was cured. However, heart failure associated with anti-cancer treatment presented, most probably related to chemotherapy containing anthracycline. After active treatment, her cardiac function returned to normal. Unfortunately, follow-up visits revealed a second primary malignancy, lymphoma. After multiple courses of chemotherapy combined with targeted therapy, her lymphoma acquired complete remission and no cardiotoxicity was observed again. Heart failure related to breast treatment may be reversible. CONCLUSION Using alternatives to anthracycline in patients with lymphoma who are at risk of cardiac failure may preserve cardiac function.

Resolving Deep Sub-Wavelength Scattering of Nanoscale Sidewalls Using Parametric Microscopy

The quantitative optical measurement of deep sub-wavelength features with sub-nanometer sensitivity addresses the measurement challenge in the semiconductor fabrication process.Optical scatterings from the sidewalls of patterned devices reveal abundant structural and material information.We demonstrated a parametric indirect microscopic imaging(PIMI)technique that enables recovery of the profile of wavelength-scale objects with deep sub-wavelength resolution,based on measuring and filtering the variations of far-field scattering intensities when the illumination was modulated.The finite-difference time-domain(FDTD)numerical simulation was performed,and the experimental results were compared with atomic force microscopic(AFM)images to verify the resolution improvement achieved with PIMI.This work may provide a new approach to exploring the detailed structure and material properties of sidewalls and edges in semiconductor-patterned devices with enhanced contrast and resolution,compared with using the conventional optical microscopy,while retaining its advantage of a wide field of view and relatively low cost.

New determination of the^7Be ground state spectroscopic factor and the^6Li(p,γ)^7Be astrophysical S(E)factors

The ＇lithium problem, in Big Bang nucleosynthesis（BBN） has recently focused on reactions involving ^7 Be.The ^6 Li（p,γ）^7 Be reaction can provide us not only with information about ^6 Li destruction but also with information about ^7 Be production. In the present work, the proton spectroscopic factor in ^7 Be is extracted to be 0.70 ± 0.17 from the angular distribution of ^7 Be（d, ^3 He）^6 Li at Ec.m. = 6.7 MeV. This value is then used to compute the direct component of the astrophysical ^6 Li（p,γ）^7 Beg.s. S（E） factors and determine the resonance parameters from the total S（E） factors.

Measurement of the^2H(^7Be,^6Li)^3He reaction rate and its contribution to the primordial lithium abundance

In the standard Big Bang nucleosynthesis （SBBN） model, the lithium puzzle has attracted intense interest over the past few decades, but still has not been solved. Conventionally, the approach is to include more reactions flowing into or out of lithium, and study the potential effects of those reactions which were not previously considered. 7Be（d, 3He）6Li is a reaction that not only produces 6Li but also destroys 7Be, which decays to 7Li, thereby affecting 7Li indirectly. Therefore, this reaction could alleviate the lithium discrepancy if its reaction rate is sufficiently high. However, there is not much information available about the 7Be（d, 3He）6Li reaction rate. In this work, the angular distributions of the 7Be（d, 3He）6Li reaction are measured at the center of mass energies Ecm=4.0 MeV and 6.7 MeV with secondary 7Be beams for the first time. The excitation function of the 7Be（d, 3He）6Li reaction is first calculated with the computer code TALYS and then normalized to the experimental data, then its reaction rate is deduced. A SBBN network calculation is performed to investigate its influence on the 6Li and 7Li abundances. The results show that the 7Be（d, 3He）6Li reaction has a minimal effect on 6Li and 7Li because of its small reaction rate. Therefore, the 7Be（d, 3He）6Li reaction is ruled out by this experiment as a means of alleviating the lithium discrepancy.

Direct measurement of the resonance strengths and branching ratios of low-energy(p,γ)reactions on Mg isotopes

Proton capture reactions on Mg isotopes are significant in the Mg-Al cycle in stellar H-burning.In particular,the resonance strengths and branching ratios of low-energy resonances in 23Mg(p,γ)26Al reactions determine the production of which is one of the most important long-lived radioactive nuclei in nuclear astrophysics.In this article,we report our first experiment using the intense proton beam of approximately 2 mA provided by the JUNA accelerator ground laboratory and a new technique that can minimize the composition change of targets under intense beam irradiation.The resonance strengths and branching ratios of E=214,304,and 326 keV resonances in the reactions of 2~4Mg(p,γ)25Al,25Mg(p,γ)26Al,and 26Mg(p,γ)27Al,respectively,were measured with high accuracy.The success of this experiment provides a good calibration for the nuclear astrophysical experiment at the Jinping underground laboratory.

Astrophysical 22Mg(p,γ)23Al reaction rates from asymptotic normalization coefficient of 23Ne→22Ne+n

The radionuclide 22Na generates the emission of a characteristic 1.275 MeVγ-ray.This is a potential astronomical observable,whose occurrence is suspected in classical novae.The 22Mg(p,γ)23Al reaction is relevant to the nucleosynthesis of 22Na in Ne-rich novae.In this study,employing the adiabatic distorted wave approximation and continuum discretized coupled channel methods,the squared neutron asymptotic normalization coefficients(ANCs)231 for the virtual decay of Ne→22Ne+n were extracted,and determined as(0.483±0.060)fm-1 and(9.7±2.3)fm-1 for the ground state and the first excited state from the experimental angular distributions of 22Ne(d,p)23Ne populating the ground state and the first excited state of 23Ne,respectively.Then,the squared proton ANC of 23Alg.s.was obtained as Cd5/22(23Al)(2.65±0.33)×103 fm-1 according to the charge symmetry of the strong interaction.The astrophysical S-factors and reaction rates for the direct capture contribution in 22Mg(p,γ)23Al were also presented.Furthermore,the proton width of the first excited state of 23Al was derived to be(57±14)eV from the neutron ANC of its mirror state in 23Ne and used to compute the contribution from the first resonance of 23Al.This result demonstrates that the direct capture dominates the 22Mg(p,γ)23Al reaction at most temperatures of astrophysical relevance for 0.33<T9<0.64.

The angular distributions of elastic scattering of^12,13C+Zr

To obtain the neutron spectroscopic amplitudes for 90-96Zx overlaps experimental data of elastic scatter-ing with small experimental errors and precise optical potentals were anary exin othe hiohpyecision o3D magneticangular distributions of^12,^13C+^AZr(A=90,91,92,94,96)were measured using the high-precision Q3D magnetic spectrometer in the Tandem accelerator.The Sao Paulo potential was used for the optical potential.The optical mod-el and coupled channel calculations were compared with the experimental data.The theoretical results were found tobe very close to the experimental data.In addition,the possible effects of the couplings to the inelastic channels of the^AZr targets and 12,13^C projectiles on the elastic scattering were studied.It was observed that the couplings to the in-elastic channels of the^12,^13C projectiles could improve the agreement with the experimental data,while the inelasticcouplings to the target states are of minor importance.The effect of the one-neutron stripping in the^13C+^AZr elasticscattering was also studied.The one-neutron stripping channel in^13C+^AZr was found to be not relevant and did notaffect the elastic scattering angular distributions.Our results also show that in the reactions with the considered zir-conium isotopes,the presence of the extra neutron in^13C does not influence the reaction mechanism,which is gov-erned by the collective excitation of the^12C core.