深化实验教学体系改革,推进国家级实验教学示范中心高质量发展——化学国家级实验教学示范中心(厦门大学)建设与成效

化学国家级实验教学示范中心(厦门大学)以培养拔尖创新型人才为目标,持续深化实验教学体系改革,全新构建了多学科交叉融合的“中心科学”实验教学新体系,同时,积极探索实验中心建设与管理的新模式,通过整合和共享优质资源,构建具备多学科交叉融合特色的教学团队,打造一个科教协同的育人环境,为学生提供一个培养创新实践能力的平台。通过一系列创新实践,有力推进了实验中心的高质量发展,全面提升人才培养质量,为学校双一流建设提供重要支撑。

A YOLOv8-CE-based real-time traffic sign detection and identification method for autonomous vehicles

Traffic sign detection in real scenarios is challenging due to their complexity and small size,often preventing existing deep learning models from achieving both high accuracy and real-time performance.An improved YOLOv8 model for traffic sign detection is proposed.Firstly,by adding Coordinate Attention(CA)to the Backbone,the model gains location information,improving detection accuracy.Secondly,we also introduce EIoU to the localization function to address the ambiguity in aspect ratio descriptions by calculating the width-height difference based on CIoU.Additionally,Focal Loss is incorporated to balance sample difficulty,enhancing regression accuracy.Finally,the model,YOLOv8-CE(YOLOv8-Coordinate Attention-EIoU),is tested on the Jetson Nano,achieving real-time street scene detection and outperforming the Raspberry Pi 4B.Experimental results show that YOLOv8-CE excels in various complex scenarios,improving mAP by 2.8%over the original YOLOv8.The model size and computational effort remain similar,with the Jetson Nano achieving an inference time of 96 ms,significantly faster than the Raspberry Pi 4B.

普通真空血液采集管对血锌检测结果影响的评估

目的通过比较不同品牌的普通血液采集管与BD公司微量元素专用血液采集管本底锌水平的差异,评估普通血液采集管对血锌检测的影响。方法本研究选择7种不同品牌的普通血液采集管和BD公司微量元素专用血液采集管为研究对象,应用血锌稀释液模拟血液样本,采用火焰原子吸收光谱法检测不同品牌血液采集管本底锌的含量。结果管帽是进口品牌B、C、D和国产品牌A普通血液采集管本底锌的来源;国产品牌B和C本底锌除了主要存在于管帽中外,在管壁和分离胶中也存在少量的锌元素。结论普通血液采集管未经过无锌化处理,其管帽、管壁和分离胶均可能含有不同浓度的本底锌,污染待测血液样本,导致血锌结果偏高;微量元素专用血液采集管经过无锌化处理,可有效避免该情况的发生。

3D printing of calcium phosphate bioceramic with tailored biodegradation rate for skull bone tissue reconstruction

The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.

Project-based Learning in Calculus on The Use of Maple Software Technology

In this article, authors describe how to use the project-based learning （PBL） pedagogy to enhance students＇ Calculus learning based on the first author＇s experimental teaching experience. The ＂2014 BMCC Polar Art Calendar＂ project was completed by Calculus students at Borough of Manhattan Community College （BMCC） during the fall 2013 semester. Students were requested to apply graphs of polar equations to create computer-generated images with a variety of flower patterns by using the Maple technology in a math lab. At the end of this project, students were requested to submit and present their written reports to express their mathematical thinking. Authors also explain in details how to create projects compatible with textbook knowledge learning objectives, how to prepare scaffolding materials for students to use, how to utilize a math lab and to work with lab technicians in Maple Software, and how to design a rubric for project evaluations. Students＇ artwork created in the Polar Art Calendar are presented. Students＇ positive outcomes have proven a success of this project design as well as its execution as an example of PBL. Benefits to students and challenges to teachers on the use of PBL approach have been discussed at the end of this article.

Altered mitochondria and Bcl-2 expression in the hippocampal CA3 region in a rat model of acute epilepsy

BACKGROUND： Previous studies have shown that the mitochondrial structure and function are damaged in animal models of epilepsy. In addition, the Bcl-2 protein is capable of regulating mitochondrial stability. OBJECTIVE： To observe and validate changes in mitochondrial structure and Bcl-2 expression, and to analyze these characteristics in the hippocampal CA3 region of rat models of epilepsy. DESIGN, TIME AND SETTING： This randomized, controlled, animal experiment was performed at the Laboratory of Electron Microscopy and Department of Histology and Embryology, Luzhou Medical College between 2007 and 2008. MATERIALS： Coriamyrtin was provided by the Pharmacy Factory of West China University of Medical Sciences. The primary and secondary antibodies were provided by Zhongshan Goldenbridge Biotechnology, Beijing. METHODS： A total of 44 adult, male, Sprague Dawley rats were randomly divided into control （n = 11） and epilepsy （n = 33） groups. Rats in the epilepsy group were induced by coriamyrtin （50 μ g/kg）, which was injected into the lateral ventricles. The rats were then observed at 3, 6, and 24 hours after epilepsy induction, with 11 rats at each time point. Epilepsy was not induced in rats from the control group. MAIN OUTCOME MEASURES： Pathological changes in the hippocampal CA3 region were observed by light microscopy; Bcl-2 expression was analyzed by immunohistochemistry; and mitochondrial changes in the hippocampus were observed under transmission electron microscopy. RESULTS： （1） The control group displayed very little Bcl-2 protein expression in the hippocampal CA3 region. However, after 3 hours of epilepsy, expression was visible. By 6 hours, expression peaked and then subsequently decreased after 24 hours, but remained higher than the control group （P 〈 0.05）. （2） Mitochondria were damaged to varying degrees in the epilepsy groups. For example, mitochondria edema, cristae space increase, and disappearance of mitochondria were apparent. Moreover, mitochondrial damage occurred prior to pathological changes in the neurons and nucleolus. CONCLUSION： Bcl-2 expression and mitochondrial damage increased in the hippocampal CA3 region in rats with epilepsy. Moreover, mitochondrial damage occurred prior to increased Bcl-2 expression and nucleolus damage.

A phylogeny of the Passerida(Aves: Passeriformes)based on mitochondrial 12S ribosomal RNA gene

Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.

CEPC Technical Design Report

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.

Long-term hepatitis B surface antigen kinetics after nucleos(t)ide analog discontinuation in patients with noncirrhotic chronic hepatitis B

Background and aim Few studies have reported hepatitis B surface antigen(HBsAg)kinetics after nucleos(t)ide analog(NA)discontinuation in patients with noncirrhotic chronic hepatitis B(CHB).The study specifically investigated long-term HBsAg kinetics after NA discontinuation.Methods Between January 2014 to January 2024,this study prospectively enrolled 106 outpatients with noncirrhotic CHB who met the discontinuation criteria after NA consolidation treatment.Demographic,clinical,and laboratory data were collected and analyzed after NA discontinuation.Results Ninety-six patients who finished 5 years of follow-up were included.HBsAg remained undetectable in 29 patients with end of treatment(EOT)HBsAg negativity.Among 67 patients with EOT HBsAg positivity,HBsAg seroclearance occurred in 12(17.9%)patients with an estimated annual incidence of HBsAg seroclearance of 3.6%.Patients with EOT HBsAg levels of≤1000 IU/mL had a higher HBsAg seroclearance rate than those with EOT HBsAg levels of>1000 IU/mL(33.3%vs.5.4%).The proportion of patients with HBsAg≤1000 IU/mL increased during follow-up.Logistic regression analysis indicated that the EOT HBsAg level was an independent factor for HBsAg seroclearance and an HBsAg level decline exceeding 1 log10 IU/mL.The optimal EOT HBsAg cutoff for both HBsAg seroclearance and an HBsAg level decline exceeding 1 log10 IU/mL was 359 IU/mL.Conclusions Patients with EOT HBsAg negativity experienced no relapse and maintained HBsAg seroclearance during 5 years of follow-up after NA discontinuation.A higher HBsAg seroclearance rate can be obtained in patients with EOT HBsAg levels of≤1000 IU/mL during 5 years of follow-up after NA discontinuation.Close monitoring and proper NA retreatment are recommended to guarantee the safety of NA discontinuation.

Calibration of the cryogenic measurement system of a resonant haloscope cavity

Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities.In this paper,we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor Q_(1)=10^(4)whose operation at a temperature of 22 mK is based on a dilution refrigerator.Our readout system consists of High Electron Mobility Transistors working as cryogenic amplifiers at 4 K,plus room-temperature amplifiers and a spectrum analyzer for signal power detection.We tested the system with a superconducting two-level system based on a single-photon source in the microwave frequency regime.We obtained an overall 95.6 dB system gain and–71.4 dB attenuation in the cavity's input channel.The effective noise temperature of the measurement system is 7.5 K.

Recent progress and clinical applications of advanced biomaterials in cosmetic surgery

Materials of different allogeneic or xenogeneic or autologous origins are widely used as soft-tissue fillers or structural scaffolds in the field of cosmetic surgery,while complications including prosthesis infection,donor site deformity and filler embolization have always been difficult problems for plastic surgeons.The application of novel biomaterials may bring in hopeful solutions for these problems.Recently,some advanced biomaterials,such as regenerative biomaterials can effectively promote the repair of defective tissues,which have been proven to have good therapeutic as well as cosmetic effects in cosmetic surgery.Therefore,biomaterials with active compounds have drawn significant attention for the tissue regeneration of reconstructive and esthetic treatment.Some of these applications have achieved better clinical outcomes than traditional biological materials.This review summarized recent progress and clinical applications of advanced biomaterials in cosmetic surgery.

Recent advances in metal organic frameworks for the catalytic degradation of organic pollutants

Metal organic frameworks(MOFs)with their large surface area and numerous active sites have attracted significant research attention.Recently,the application of MOFs for the catalytic degradation of organic pollutants has provided effective solutions to address diverse environmental problems.In this review,the latest progress in MOF-based removal and degradation of organic pollutants is summarized according to the different roles of MOFs in the removal reaction systems,such as physical adsorbents,enzyme-immobilization carriers,nanozymes,catalysts for photocatalysis,photo-Fenton and sulfate radical based advanced oxidation processes(SR-AOPs).Finally,the opportunities and challenges of developing advanced MOFs for the removal of organic pollutants are discussed and anticipated.

Applications and challenges for single-bacteria analysis by flow cytometry

Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.

Doxorubicin-loaded bacterial outer-membrane vesicles exert enhanced anti-tumor efficacy in non-small-cell lung cancer

More efficient drug delivery system and formulation with less adverse effects are needed for the clinical application of broad-spectrum antineoplastic agent doxorubicin(DOX). Here we obtained outer-membrane vesicles(OMVs), a nano-sized proteoliposomes naturally released by Gram-negative bacteria, from attenuated Klebsiella pneumonia and prepared doxorubicin-loaded O0MVs(DOX-OMV). Confocal microscopy and in vivo distribution study observed that DOX encapsulated in OMVs was efficiently transported into NSCLC A549 cells. DOX-OMV resulted in intensive cytotoxic effects and cell apoptosis in vitro as evident from MTT assay, Western blotting and flow cytometry due to the rapid cellular uptake of DOX. In A549 tumor-bearing BALB/c nude mice, DOX-OMV presented a substantial tumor growth inhibition with favorable tolerability and pharmacokinetic profile, and TUNEL assay and H&E staining displayed extensive apoptotic cells and necrosis in tumor tissues. More importantly, OMVs’ appropriate immunogenicity enabled the recruitment of macrophages in tumor microenvironment which might synergize with their cargo DOX in vivo. Our results suggest that OMVs can not only function as biological nanocarriers for chemotherapeutic agents but also elicit suitable immune responses, thus having a great potential for the tumor chemoimmunotherapy.

Distinct regulatory mechanism of immunoglobulin gene transcription in epithelial cancer cells

The restriction of immunoglobulin(Ig)expression to B lymphocytes is well established.However,several reports have confirmed that the Ig gene can be expressed in many non-B cancer cells and/or some normal cells.Our aim is to determine whether the Ig gene promoter can be activated in non-B cancer cells and to identify the regulatory mechanism for Ig gene expression.Our results show that the Ig promoter of VH4-59 was activated in several non-B cancer cell lines.Moreover,two novel positive regulatory elements,an enhancer-like element at 2800 to 2610 bp and a copromoter-like element at 2610 to 2300 bp,were identified in two epithelial cancer cell lines,HeLa S3 and HT-29.The octamer element(59-ATGCAAAT-39)located in the Ig promoter,a crucial element for B-cell-derived Ig gene transcription,was also very important for non-B-cell-derived Ig gene transcription.More importantly,we confirmed that octamer-related protein-1(Oct-1),but not Oct-2,was a crucial transcriptional factor for Ig gene transcription due to its ability to bind to the octamer element of the Ig promoter in epithelial cancer cells.These results suggested the presence of a distinct regulatory mechanism for Ig gene expression in non-B cancer cells.

A green synthesis of carbon nanoparticles from honey and their use in real-time photoacoustic imaging

Imaging sentinel lymph nodes （SLN） could provide us with critical information about the progression of a cancerous disease. Real-time high-resolution intrao- perative photoacoustic imaging （PAI） in conjunction with a near-infrared （NIR） probe may offer opportunities for the immediate imaging for direct identification and resection of SLN or collecting tissue samples. In this work a commercially amenable synthetic methodology is revealed for fabricating luminescent carbon nanoparticles with rapid clearance properties. A one-pot ＂green＂ technique is pursued, which involved rapid surface passivation of carbon nanopartides with organic macromolecules （e.g., polysorbate, polyethyleneglycol） in solvent-free conditions. Interestingly, the naked carbon nanoparticles are derived for the first time, from commercial food grade honey. Surface coated particles are markedly smaller （-7 nm） than previously explored particles （gold, single-walled carbon nanotubes, copper） for SLN imaging. The results indicate an exceptionally rapid signal enhancement （-2 min） of the SLN. Owing to their strong optical absorption in the NIR region, tiny size and rapid lymphatic transport, this platform offers great potential for faster resection of SLN and may lower complications caused in axillary investigation by mismarking with dyes or low-resolution imaging techniques.

财政政策与企业投资

本文基于中国A股上市公司1999—2017年的数据,研究中国财政政策对企业投资行为的影响。研究发现:(1)积极财政政策的实施能够提升企业的投资水平,但会降低企业投资的资源配置效率;(2)财政政策对企业投资的影响具有较好的时效性,能够在短期内迅速生效且效果能够长期持续,而且在各地区、各行业表现出一定的普适性;(3)关于积极的财政政策对企业投资水平的促进作用,非国有企业强于国有企业,而关于企业投资对未来业绩的促进作用,国有企业强于非国有企业。上述结果表明,积极财政政策能够提高企业投资水平,而政府对企业投资的指导作用能够提高企业投资的科学性和合理性,加强投资转化为收入和产出的能力,避免投资过量和产能过剩。本文的研究结论可以为政府部门财政政策的制定和实施以及企业管理者投资决策的制定提供一定的借鉴。

Effects of the SAPO-11 synthetic process on dehydration of ethanol to ethylene

The effects of the synthetic condition of SAPO-11 molecular sieves on ethanol dehydration to ethylene were studied.Product-compositions,ethanol conversion,and selectivity to ethylene of synthesized and commercial SAPO-11 molecular sieves were compared.Results are as follows:the optimal synthetic conditions for SAPO-11 molecular sieves are adding pseudoboehmite before orthophoshporic,using di-npropylamine as the template,having a mass fraction of 40%colloidal silica as the silica source and the starting gel obtained,and running at 200℃ for 48 h.From the patterns of NH3-TPD,the amount of acid synthesized by SAPO-11 molecular sieves is less than that by commercial SAPO-11 molecular sieves,and has a stronger weak acid.Also,ethanol conversion and selectivity to ethylene reached 99%at 280℃ on synthesized SAPO-11,lower by 20℃ compared to commercial SAPO-11.For two SAPO-11 molecular sieves,the by-products in the gas phase are mainly ethane,propane,propene,isobutane,n-butane,propadiene,butylene and some higher hydrocarbons.The by-products in the liquid phase are ethyl ether and acetaldehyde.

A low-cost and high-efficiency 10-in-1 test for the PCR-based screening of SARS-CoV-2 infection in low-risk areas

To the Editor:As of August 9,2020,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has infected 19,432,244 people and caused 721,594 deaths globally.To timely identify the infected persons,nucleic acid detection screenings have been carried out for high-infection risk groups in areas known to have coronavirus disease 19(COVID-19)cases,such as Wuhan,Beijing,and Xinjiang.The rapid identification of infected patients and the implementation of quarantine measures play an important role in preventing the transmission of SARS-CoV-2.However,there are some issues associated with large-scale screening for this virus.The consumption of equipment and reagents for specimen collection and detection is high,resulting in elevated screening costs.Moreover,with the increase in the number of samples collected,the testing capabilities of medical institutions have reached a saturation point,hindering the speed and scope of large-scale screenings.For this reason,the mixed detection after RNA extraction(detection in a mixture of nucleic acids extracted from several patients)or before RNA extraction(detection in a mixture of pharyngeal swab transfer buffer obtained from different patients before nucleic acid extraction)has been proposed in many regions.[1]However,both the pooling of swab transfer buffer before nucleic acid extraction and pooling of RNA after nucleic acid extraction inevitably cause dilution of samples and decrease of detection sensitivity.However,there is still a lack of research on how to effectively improve the screening efficiency and control the decrease of sensitivity caused by dilution in an appropriate range.In this study,we designed a novel 10-in-1 test(ten pharyngeal swab samples from ten individuals were placed in one custom-made virus collection tube[CMT]for nucleic acid extraction and testing)by optimizing the current mixed acquisition technique,and after a promising pilot test.

The upper bound on the tensor-to-scalar ratio consistent with quantum gravity

We consider the polynomial inflation with the tensor-to-scalar ratio as large as possible which can be consistent with the quantum gravity(QG) corrections and effective field theory(EFT). To get a minimal field excursion ΔΦ for enough e-folding number N, the inflaton field traverses an extremely flat part of the scalar potential, which results in the Lyth bound to be violated. We get a CMB signal consistent with Planck data by numerically computing the equation of motion for inflaton Φ and using Mukhanov–Sasaki formalism for primordial spectrum. Inflation ends at Hubble slow-roll parameter ε_(1)^(H)=1 or a=0. Interestingly, we find an excellent practical bound on the inflaton excursion in the format a+b√r, where a is a tiny real number and b is at the order 1. To be consistent with QG/EFT and suppress the high-dimensional operators, we show that the concrete condition on inflaton excursion is M_(PI)/△_(Ф)<0.2×√10≈0.632. For n_(s)= 0.9649,N_(e)= 55, and M_(PI)/△_(Ф)<0.632 MPl, we predict that the tensor-to-scalar ratio is smaller than 0.0012 for such polynomial inflation to be consistent with QG/EFT.