Preservation efficiency of new cryoprotectant used for Acidithiobacillus ferrooxidans in liquid nitrogen

The efficiency of a new cryoprotectant,GP,for the preservation of Acidithiobacillus ferrooxidans（A.ferrooxidans） strain DC in liquid nitrogen was investigated.The optimal concentration of this new cryoprotectant for the maximal viable cell recovery and the highest ferrous ion oxidation activity was determined.The results show that 30%（volume fraction） GP is optimal for the cryopreservation with 84.4% of cells surviving,completely oxidizing ferrous ions within 120 h,and growing to a final density of 5.8×107 cell/mL after 6 d in the culture.Furthermore,the optimal residual GP concentration for viable cell recovery after culture of thawed cells in 9K medium for 6 d is 0.6%（volume fraction）.At this concentration,strain DC completely oxidizes ferrous ions within 108 h and grows to a final cell density of 6.8×107 mL-1.Thus,GP is a simple,effective cryoprotectant for the preservation of A.ferrooxidans strain DC in liquid nitrogen.

猪传染性胃肠炎病毒RT-CPA检测方法构建及初步应用

为开发一种猪传染性胃肠炎病毒(Transmissible gastroenteritis virus,TGEV)RT-CPA快速且准确的检测方法。本试验根据TGEV S基因的D序列,设计了3对引物,使用构建的重组质粒作为标准阳性对照,通过优化筛选条件并应用可视化核酸试纸条,成功建立了一种一步法TGEV RT-CPA检测方法。本实验筛选最优条件为:Mg^(2+)浓度1.0 mmol/L,dNTP浓度0.8 mmol/L,Betaine浓度1.0 mol/L,BstDNA聚合酶浓度8.0 U,反应温度63℃,反应时间60 min,AMV逆转录酶5 U。本研究的扩增产物通过凝胶电泳显示出梯形条带,证明了其对TGEV的特异性检测和重复性良好,灵敏度高达10拷贝/μL。初步应用显示,该方法与TGEV抗原快速检测试剂盒的符合率超过90%,显示了高灵敏度。TGEV RT-CPA方法免去了RNA提取和cDNA合成的步骤,能够完成一步检测,且该方法不需要特殊仪器,适用于现场快速检测TGEV,为快速诊断和防控猪传染性胃肠炎提供了新的技术选择。

Effects of cryoprotectant treatments on bovine sperm function and osmolyte content

The hypothesis that addition and removal of cryoprotectants to and from spermatozoa would initiate regulatory volume decrease, and lead to osmolyte loss and reduced sperm function, was tested. Common cryoprotectants, in the absence of freezing and thawing, affected bovine ejaculated spermatozoa by lowering their total and progressive motility in medium, reducing their migration through surrogate cervical mucus, damaging sperm head membranes and inducing sperm tail coiling. Sperm function was slightly better maintained after cryoprotectants were added and removed in multiple small steps rather than in a single step. The intracellular content of the polyol osmolytes, D-sorbitol and myo-inositol, exceeded that of the zwitterion osmolytes, L-carnitine and L-glutamate. Certain cryoprotectants reduced intracellular L-camitine and L-glutamate concentration but not that of myo-inositol or D-sorbitol. Multistep treatments with some cryoprotectants had advantages over one-step treatments in mucus penetration depending on the original amount of intracellular camitine and glutamate in the spermatozoa. Overall, sperm quality was best maintained by multistep treatment with glycerol and propanediols that were associated with decreased intracellular glutamate concentration. Bovine spermatozoa seem to use glutamate to regulate cryoprotectant-induced cell swelling.

Improved cryopreservation of human hepatocytes using a new xeno free cryoprotectant solution

AIM:To optimize a xeno-free cryopreservation protocol for primary human hepatocytes.METHODS:The demand for cryopreserved hepatocytes is increasing for both clinical and research purposes.Despite several hepatocyte cryopreservation protocols being available,improvements are urgently needed.We first compared controlled rate freezing to polystyrene box freezing and did not find any significant change between the groups.Using the polystyrene box freezing,we compared two xeno-free freezing solutions for freezing of primary human hepatocytes:a new medium(STEM-CELLBANKER,CB),which contains dimethylsulphoxide(DMSO) and anhydrous dextrose,both permeating and non-permeating cryoprotectants,and the frequently used DMSO-University of Wisconsin(DMSOUW) medium.The viability of the hepatocytes was assessed by the trypan blue exclusion method as well as a calcein-esterase based live-dead assay before and after cryopreservation.The function of the hepatocytes was evaluated before and after cryopreservation by assessing enzymatic activity of 6 major cytochrome P450 isoforms(CYPs):CYP1A2,CYP2C9,CYP2C19,CYP2D6,CYP3A4 and CYP3A7.RESULTS:The new cryoprotectant combination preserved hepatocyte viability significantly better than the standard DMSO-UW protocol(P < 0.01).There was no significant difference in viability estimation between both the trypan blue(TB) and the Live-Dead Assay methods.There was a correlation between viability of fresh hepatocytes and the difference in cell viability between CB and DMSO protocols(r 2 = 0.69) using the TB method.However,due to high within-group variability in the activities of the major CYPs,any statistical between-group differences were precluded.Cryopreservation of human hepatocytes using the cryoprotectant combination was a simple and xeno-free procedure yielding better hepatocyte viability.Thus,it may be a better alternative to the standard DMSO-UW protocol.Estimating CYP activities did not seem to be a relevant way to compare hepatocyte function between different groups due to high normal variability between different liver samples.CONCLUSION:The cryoprotectant combination may be a better alternative to the standard DMSO-UW protocol in primary human hepatocyte cryopreservation.

EFFECTS OF DIFFERENT COMBINATIONS OF CRYOPROTECTANTS ON SPERMATOZOON VITALITY OF CHINESE SCALLOP,CHLAMYS FARRERI,DURING LOW TEMPERATURE EQUILIBRIUM

The effects of membrane penetrating anti-freezing agents(MPAAs), DMSO(dimethyl sulfoxide),glycerol,EG(ethylene glycol) and methanol in combination with different cryoprotective additives suchas carbohydrates,macromolecules and inorganic compounds on the spermatozoon vitality of Chinesescallop,Chlamys farreri,during 1 h 0℃ equilibrium were investigated.When only MPAAs existed,the detrimental effects of different MPAAs ranked in the following order:DMSO【methanol【EG【glycerol.When carbohydrates were added into MPAAs solution,5% glucose caused larger decrease ofspermatozoon vitality than 2.4% lactose.5% glucose or 2.4% lactose in 7.5% glycerol caused com-plete damage.10% yolk was best in maintaining the spermatozoon vitality except when used incombination with 10% methanol.10% milk significantly decreased spermatozoon vitality in EG andmethanol and enhanced its vitality in glycerol,but did not significantly influence it in DMSO.Glycinewas apparently detrimental to spermatozoon vitality.The average

Exploring novel cell cryoprotectants based on neutral amino acids

Cryoprotectants play a key role in cell cryopreservation because they can reduce cryoinjuries to cells associated with ice formation.To meet the clinical requirements of cryopreserved cells,cryoprotectants should be biocompatible,highly efficient and easily removable from cryopreserved cells.However,integration of these properties into one cryoprotectant still remains challenging.Herein,three biocompatible neutral amino acids,includingβ-alanine,γ-aminobutyric acid andε-aminocaproic acid,are first reported to have the potential as such ideal cryoprotectants.The results demonstrate that they can inhibit ice formation and reduce osmotic stress to provide extracellular and intracellular protection,thereby ensuring high cryopreservation efficiency for both anuclear and nucleated cells.More importantly,due to the remarkable osmotic regulation ability,the neutral amino acids can be rapidly removed from cryopreserved cells via a one-step method without causing observable damage to cells,superior to the current state-of-the-art cryoprotectants—dimethyl sulfoxide and glycerol.This work provides a new perspective to develop novel cryoprotectants,which may have dramatic impacts on solvent-free cryopreservation technology to support the cell-based applications,such as cell therapy and tissue engineering,etc.

Study on Cryopreservative Effect of Three Penetrating Cryoprotectants with Three Kinds of Extenders on Rabbit Spermatozoa

Glycerol,dimethyl suffixod (DMSO) and acetamide were adopted to verify the cryoprotective ability of penetrating cryoprotectants with three kinds of extenders for rabbit sperm. Three extenders (A,B and C) and three level of the final concentrations of glycerol and DMSO (2%, 3% and 4% ),and acetamide 2%,4% and 5% were used with Extender A, 4% glycerol had better cryoprotective effect for rabbit sperm motility and 5% acetamide was better with Extender C. 4% acetamide was better in being combined with Extender A for sperm acrosome integrity ratio,5% acetamide was better with Extender B and 2% acetamide was better with Extende C. With extender A,there was not difference among three penetrating cryoprotectants for plasma membrane integrity. With Extender B, 3% glycerol was better than 4% acetamide for plasma membrane in- tegrity,and 3% glycerol with Extender C was better than 2% - 4% DMSO and 2% acetamide.

CPA方程计算醇、水的比热容性质

针对立方型附加缔合项(CPA)状态方程(EoS)对比热容的计算精度不高的问题,采用11种包含不同性质的参数计算方法研究了CPA方程对极性缔合流体甲醇、乙醇、水比热容的计算精度。计算结果表明:不考虑比热容时,CPA方程的参数计算必须考虑蒸汽压性质,且蒸汽压计算精度越高,方程对液相比热容的预测精度越高;在参数计算中加入比热容后,CPA方程无法同时准确描述所有比热容性质,其中对液相比定压热容的计算精度最高;在参数计算过程中比热容性质只考虑液相比定压热容时,方程对蒸汽压、各相密度及液相比定压热容的平均绝对相对偏差都在3%及以内。

ACCA、CPA职业教育与会计学本科教育融合研究

在目前数字经济快速发展中,会计教学的国际化和实践能力是特别重要的内容,该文阐述会计本科教育与职业教育中的CPA和ACCA教育的异同,分析会计本科教育教学中遇到的困难和挑战及建议与对策,并进行会计学本科教育中融入职业教育的路径分析。

Effect of Combinations of Sucrose and Cryoprotectants on the Survival of Catfish Embryos （Pangasidae hypophthamus）

Although cryopreservation of embryos has been used in most terrestrial animals, the application of this technique has not been succeeded for aquatic animals. In this study, the authors investigate the effect of different combinations of sucrose （SUC, C12H22OH） and cryoprotectants （CPAs） on the survival of the catfish embryos （Pangasidae hypophthalmus） at low temperatures （4, 0 and -20 ℃） for short-term storage. For this aim, embryos with somites and optic cups were exposed to different combinations of sucrose with methanol （SUC ＋ MeOH）, 1.2-propylene glycol （SUC ＋ PROH） and ethylene glycol （SUC ＋ EG） at four concentrations ratios： （1） 0.5 M SUC ＋ 0.5 M CPA; （2） 1 M SUC ＋ 0.5 M CPA; （3） 0.5 M SUC ＋ 1 M CPA; （4） 1 M SUC ＋ 1 M CPA for 40 min at 4, 0 and -20 ℃. Embryos kept in water at room temperature （RT）, 4, 0 and -20℃ were used as controls. The survival rate was expressed as a percentage of hatched embryos per total embryos treated. The results showed that the hatching rate declined significantly when embryos were stored in water at 0 ℃ and -20℃. For embryos at 0 ℃ storage, the highest survival rate （87.78%） was obtained with 1 M SUC ＋ 1 M MeOH combination while at -20 ℃, only embryos in the combined treatments of 0.5 M SUC ＋ 1 MEG and 0.5 M SUC ＋ 1 M PROH reached the hatching stage （40% and 83.33%, respectively）. In conclusion, the results showed that the catfish embryos are sensitive to sub-zero temperatures and the combined treatment of 0.5 M sucrose and 1 M propylene glycol can be used to protect catfish embryos from damages caused by low temperature （0 ℃ and -20 ℃）.

CPA高管、过度自信与企业避税

文章以2012-2021年我国沪深A股上市企业为研究对象,研究了CPA高管与企业避税的关系。结果表明:高管团队中具有CPA背景的高管数量越多,企业越倾向于实施更高强度的避税行为;高管的CPA背景可能会对其信念认知产生影响,使其出现过度自信的心理偏差,产生过激避税倾向;相较于国有企业,CPA高管在非国有企业中对企业避税行为的促进作用更显著;CPA高管与公司价值正相关,但是CPA高管对企业避税的促进作用会显著损害公司价值。

基于误差修正和VMD-ICPA-LSSVM的短期风速预测建模

精准的风速预测是将风能大规模应用到电力系统中的关键,而风速序列的随机性和波动性等特点使得风速预测难度增加.为增强风速序列的可预测性,采用Logistic混沌映射策略、自适应参数调整策略以及引入变异策略对食肉植物算法(CPA)进行改进,并提出了基于误差修正和VMD-ICPA-LSSVM的短期风速预测模型.首先将气象因子作为最小二乘支持向量机(LSSVM)的输入对风速进行预测,获得误差序列.再利用K-L散度自适应地确定变分模态分解(VMD)的参数,并对误差序列进行分解.结合改进食肉植物算法(ICPA)优化LSSVM可调参数的方法来预测分解的子序列.叠加各子序列预测结果后对原始预测序列进行误差修正,进而得到最终风速预测值.实验结果表明,与其他模型相比,所提模型有着更好的预测精度和泛化性能.

R1233zd(E)制冷剂CPA状态方程

R1233zd(E)属于氢氟烯烃类(HFOs)物质,是一种新型替代制冷工质。为更加精确地描述其热力学性质,以CPA状态方程为基础,利用文献公开报道的R1233zd(E)的饱和液相密度、饱和气体密度及饱和蒸气压测量数据,拟合获取到CPA状态方程的5个参数。基于MATLAB,实现了利用CPA状态方程计算工质的热力学性质。研究结果表明:CPA状态方程在求解饱和气相密度时,精度与SRK方程相比有所降低;计算饱和液体密度和单相液体密度时的精度显著提升。

AI大模型的财务能力测评与启示——基于CPA考试的ChatGPT与国产大模型实测

在当前学界业界,尚缺乏关于AI大模型财务能力的规范化评估体系。基于该背景,本文选择CPA考试作为评估体系,针对ChatGPT、智谱清言、讯飞星火三款AI大模型财务能力展开深度测评,希望在数据可验证的范围内,呈现大模型应用于财务场景的优势与不足,并通过深入分析,处一隅而观全局,从整体层面把握AI大模型在财务行业的应用可行性及未来发展趋势。研究结果显示,三款参评大模型在2023年CPA六门真题的单科测试中均未及格,但在侧重于零散化知识理解、记忆、应用以及文本撰写能力的《税法》《经济法》《公司战略与风险管理》科目上展现出相当潜力,在需要复杂链式思维能力、高度计算准确性、文本细节深度理解的《会计》《财务成本管理》《审计》科目上存在明显不足。本文认为,在整体层面,财会行业对未来大模型的应用可持谨慎的乐观态度,并进一步从学习备考辅助、会计职能转型、财务应用场景、教学及科研四个维度,提炼了本次测评对大模型财务应用的具体借鉴及启发,以期为在校学生、CPA考生、会计专业人士、研究学者及软件开发商等提供有益参考。

基于CPA《会计》教材的会计领域分词词典构建

中文分词是会计领域文本研究的一项基本任务,在会计文本形式特征研究中发挥着重要作用。会计领域文本分词面临的一个挑战是缺乏符合会计领域用语习惯的分词词典,尤其是面向术语、常用语等领域特色的分词词典。为对会计领域的文本数据进行高效分析,基于书籍文本2023年中国注册会计师考试辅导教材《会计》,采用“jieba”中文分词模块分词和人工标注的方式,构建会计领域分词词典并对分词效果进行检验。检验结果表明,所构建的会计领域分词词典明显提升了分词效果,切分的词语体现了会计领域用语习惯,可以为会计文本研究提供参考。

新时期CPA审计质量控制刍议

CPA(注册会计师)审计质量控制在新时期面临着诸多挑战,但同时也充满机遇。论文针对新时期的CPA审计质量控制问题进行了深入探讨,梳理了新时期CPA审计质量控制的问题与面临的挑战。接着,论文提出针对上述挑战的应对策略,包括完善审计准则与质量控制标准、提升审计人员的专业能力与职业道德、完善审计质量控制体系、加强先进信息技术在审计中的应用等,以期为提高我国CPA审计质量、促进审计行业健康发展提供有益的参考。

数智时代注册会计师行业高质量发展与高校CPA人才培养研究

近年来,随着数字化技术的飞速发展和人工智能的普及,注册会计师行业面临前所未有的挑战和机遇。针对新技术对注册会计师行业的影响,分析了注册会计师行业未来发展趋势及面临的挑战,从注册会计师行业发展现状和高校CPA人才培养的方向出发,探讨如何培养符合数智化时代要求的高素质复合型人才,以推动注册会计师行业高质量发展。

基于CPA状态方程计算天然气-甲醇-水气液相平衡

采用考虑了极性分子间氢键缔合作用的立方型附加缔合项(CPA)状态方程计算了天然气-甲醇-水体系气液相平衡。根据实验测试的甲烷-水、乙烷-水、丙烷-水、正己烷-水、甲醇-水二元体系气液相平衡实验数据,拟合了CPA状态方程中甲烷、乙烷、丙烷、正己烷、甲醇与水的二元交互作用系数,提出了与烷烃摩尔质量相关的烷烃-水二元交互作用系数关联式。在此基础上,预测了天然气-甲醇-水多组分体系的气液相平衡。结果表明:在温度为283—298 K,压力为5.86—34.34 MPa的范围内,预测的气相水含量、甲醇含量与实验值之间的平均相对偏差分别为5.55%和8.09%。CPA状态方程不仅为准确预测天然气-甲醇-水体系的气液相平衡提供了依据,还可应用于其他含极性物质体系的热力学物性参数和相平衡的计算。

CPA-紫外分光光度法测定轧钢废水中的微量油含量

建立了ＣＰＡ－紫外分光光度法测定冷轧废液中油含量的新方法。该方法能准确地测定水样中的微量油含量，且能同时测定乳化剂含量。避免了常规紫外分光光度法中乳化剂对油含量测定的干扰。由于该方法采用了多波长方法，降低了个别点的偶然测量误差引起较大计算误差的可能。对合成水样进行分析，结果相对误差小于±６％。该方法操作简便，测量迅速，结果可靠。

创业板上市公司管理层舞弊行为动因及其CPA审计策略

如同其他上市公司那样,创业板上市公司是我国资本市场的一支重要且新生的力量,其管理层舞弊行为不仅会影响这些公司自身资金的有效流动,还会损害广大投资者的合法利益和资本市场的正常秩序与健康发展。本文主要针对创业板上市公司舞弊行为,分析其危害和形成原因,并从CPA审计的角度探讨如何加强审计监督才能治理和抑制其舞弊行为,以更好地维护公司各利益相关方的合法权益。