Stability and melting behavior of boron phosphide under high pressure

Boron phosphide(BP)has gained significant research attention due to its unique photoelectric and mechanical properties.In this work,we investigated the stability of BP under high pressure using x-ray diffraction and scanning electron microscope.The phase diagram of BP was explored in both B-rich and P-rich environments,revealing crucial insight into its behavior at 5.0 GPa.Additionally,we measured the melting curve of BP from 8.0 GPa to 15.0 GPa.Our findings indicate that the stability of BP under high pressure is improved within B-rich and P-rich environments.Furthermore,we report a remarkable observation of melting curve frustration at 10.0 GPa.This study will enhance our understanding of stability of BP under high pressure,shedding light on its potential application in semiconductor,thermal,and light-transmitting devices.

Detection and Identification of Six Foodborne Bacteria by Two-tube Multiplex Real Time PCR and Melting Curve Analysis

Objective This study is aimed to develop a two-tube melting curve-based multiplex real time PCR assay （MCMRT-PCR） for the simultaneous detection of six common foodborne pathogenic bacteria （diarrhoeagenic Escherichia coli, Salmonella, and 5higella in tube 1, Staphylococcus aureus, Vibrio parahaemolyticus, and Listeria monocytogenes in tube 2）. Methods A two-tube MCMRT-PCR assay was performed on 7900HT Fast Real-Time PCR System {Applied Biosystems, USA）. Amplification by PCR was optimized to obtain high efficiency. The sensitivity and specificity of assays were investigated. Results The detection limit of optimized MCMRT-PCR assay was 3.9x102 CFU/mLfor S. aureus, 4.4x102 CFU/mL for L. monocytogenes, 3.0x102 CFU/mL for Salmonella, 2.5x102 CFU/mL for Shigella, 2.1x102 CFU/mL for V. parahaemolyticus, and 1.2x102 CFU/mL for E. coll. The feasibility of MCMRT-PCR was further evaluated using artificially contaminated milk, the sensitivity was at the level of 10s CFU/mL. Conclusion A two-tube MCMRT-PCR assay using six primer sets was developed for detection of multiple pathogens. Our findings demonstrates that the proposed two-tube assay is reliable, useful and rapid for simultaneous detection of six foodborne pathogenic bacteria with an intended application in provincial Centers for Diseases Control and Prevention （CDC）.

Effect of spermine on the melting curve and melting temperature of some tRNAs

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High Resolution Melting Curve Analysis for Rapid Detection of Pyrazinamide Resistance in Mycobacterium tuberculosis Clinical Isolates

Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used for many applications. In this study, HRM assay was developed and evaluated for the detection of PZA resistance in Mycobacterium tuberculosis clinical isolates. Methods: Ninety five M. tuberculosis clinical isolates with different susceptibility patterns to anti-TB drugs were used to evaluate this assay. Isolates were phenotypically (Bactec MGIT 960) and genotypically (HRM and pncA gene sequencing) analysed for PZA resistance. Results: Bactec MGIT 960 analysis revealed that 29 of the 95 M. tuberculosis isolates were PZA resistant. In comparison to the Bactec MGIT 960, HRM showed a sensitivity of 47.7% and specificity of 74.6%, and the overall agreement between the two methods was 68.4%. Based on DNA sequencing, a correlation of 0.67 (significant at p-value pncA mutations was observed. PZA resistance was strongly associated with multi-drug resistant (MDR)-TB as it was shown in 79.3% of the MDR isolates included in the study. Conclusion: HRM is simple and useful for screening clinical M. tuberculosis isolates for PZA resistance, however, further modifications to improve its performance are required.

Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Ⅱ: Material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves

An integral constitutive equation and a set of material functions for describing the strain history of polymer melts were formulated in terms of the Cauchy-Green and Finger tensors. A simple memory function and the dependence of ηo and τt on M3.4 were derived from the theory of non-linear viscoelasticity with constraints of entanglements for polymer melts and substituted into the Oldroye-Walters-Fredickson constitutive equation. An integral constitutive equation for polymer melts was consequently obtained. Some material functions of the constitutive equation related to certain 'test flow' are examined as follows : (1) simple steady shear flow; (2) steady elongation flow; (3) small-amplitude oscillatory shear flow; (4) stress growth upon the inception of steady shear elongation flow; (5) stress relaxation (modulus and compllance). These theoretical relations for simple steady shear flow were compared with experimental data from our laboratory and references for various polymer melts and concentrated solutions. A good agreement between the theory and experiment was achieved.

Simulation of Melting Behavior of the MgSi03 Perovskite Under Lower Mantle Conditions

MgSiO 3 perovskite 的融化的曲线用分子的动力学方法在更低的披风条件下面与有效的对潜力结合被模仿。为 MgSiO 3 perovskite 模仿的州的方程在精确地在大量压力上复制试验性的数据是很成功的，这被显示出。MgSiO 3 perovskite 的模仿的融化的温度的压力依赖与最近的试验性的数据一致。为 MgSiO 3 模仿的融化的曲线首先在在 60 GPa 下面的压力是很陡峭的，然后，它与增加压力变得光滑。在核心披风边界迫使 135 GPa， MgSiO 3 perovskite 融化在 6500 K，它是比从 Zerr 和 Boehler 的试验性的数据的推测的显著地低的。

Toll样受体和白细胞介素-17单核苷酸多态性与口腔扁平苔藓易感性的相关性研究

目的探讨Toll样受体(TLR)和白细胞介素-17(IL-17)基因的遗传多态性及与口腔扁平苔藓(OLP)的相关性。方法选取病例组(OLP组)患者与对照组(未患OLP人群)外周血提取的DNA为研究对象,选取TLR与IL-17上的7个单核苷酸多态性(SNP)位点,分别是TLR3中的rs5743312、TLR2中的rs121917864和IL-17A中的5个SNP位点(rs4711998、rs3819024、rs8193036、rs3748067和rs17878530)。采用高分辨率熔解曲线分析法进行外周血细胞PCR产物基因多态性检测,并与DNA测序结果比对。统计分析SNP位点与OLP发生的相关性。结果rs5743312(TLR3)、rs3819024(IL-17A)与OLP的发生相关,并有统计学意义(P<0.05)。其余5个SNP位点未检测出与OLP相关。结论rs5743312(TLR3)和rs3819024(IL-17A)可能与OLP的易感性相关。

高分辨率熔解曲线检测结核分枝杆菌对氧氟沙星耐药性研究

评价高分辨率熔解曲线法在结核分枝杆菌氧氟沙星耐药性检测的有效性。采用传统比例法、DNA测序法、高分辨率熔解曲线法对84株结核分枝杆菌临床分离株进行氧氟沙星耐药性检测,分别以药敏结果和DNA测序结果为参照,应用卡方检验分析各检测结果之间的差异性,Kappa检验分析检测结果一致性。药敏结果显示,12株菌对氧氟沙星耐药,72株敏感。DNA测序结果显示,10株菌存在gyrA基因耐药相关突变,74株菌不存在gyrA基因耐药相关突变。高分辨率熔解曲线检测结果显示,有14株耐药株,70株敏感株。以比例法药敏结果为参照,DNA测序检测菌株耐药性的敏感性为83.3%、特异性为100%、符合率为97.6%,检测结果具有高度一致性;高分辨率熔解曲线法检测菌株耐药性的敏感性为75%、特异性为93.1%、符合率为90.5%,检测结果具有中度一致性。以DNA测序结果为参照,高分辨率熔解曲线法检测gyrA基因耐药突变的敏感性为80%,特异性为91.9%,符合率为90.4%,检测结果具有中度一致性。本研究结果表明高分辨率熔解曲线法对结核分枝杆菌氧氟沙星耐药性检测的效能良好,可用于氧氟沙星耐药结核分枝杆菌的快速辅助筛查,为早期治疗方案制定提供重要依据。

高分辨率熔解曲线快速检测结核分枝杆菌对链霉素耐药情况的研究

探讨高分辨率熔解曲线(HRM)技术检测结核分枝杆菌对链霉素耐药性的可行性。用传统药物敏感性试验进行结核分枝杆菌链霉素耐药性检测;以Rpsl和rrs的耐药决定区为靶点设计引物进行HRM分析,判断菌株是否对链霉素耐药;以药敏结果为标准,应用SPSS17.0分析两种检测结果之间的符合率;Kappa检验分析两种结果的一致性。药敏结果显示,84株菌株中有20株对链霉素耐药,64株为敏感株;HRM检测结果显示,24株菌株对链霉素耐药,60株为敏感株;以药敏结果为参照,HRM检测结核分枝杆菌对链霉素耐药性的敏感性为75%,特异性为85.9%,经Kappa检验显示,两种方法检测结果具有中度一致性。本研究结果表明HRM可快速检测结核分枝杆菌对链霉素的耐药性,具有较好的灵敏度,在耐药结核病的早期辅助诊断方面具有一定的应用价值。

115462例新生儿葡萄糖-6-磷酸脱氢酶缺乏症筛查及基因突变分析

目的了解贵阳地区葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase,G6PD)缺乏症发病情况和基因突变特点,为贵阳地区G6PD缺乏症的防治提供科学参考。方法募集该地区2020年8月至2023年1月出生的新生儿,应用荧光分析法对其血斑样本进行G6PD酶活性筛查,召回初筛阳性儿,完成G6PD酶活性诊断及多色探针荧光PCR熔解曲线法(Multicolor probe melting curve analysis method,MMCA)基因突变分析。结果共募集115462例新生儿,G6PD酶活性筛查血斑样本共筛出阳性1606例,筛查阳性率为1.39%(1606/115462),其中男性为1.83%(1130/61801)、女性0.89%(476/53661),男女新生儿G6PD酶活性初筛阳性率差异有统计学意义(P<0.01);召回初筛阳性患儿,G6PD基因突变检出率87.07%(909/1044),其中男性为90.09%(764/848),女性为73.98%(145/196),男女间G6PD基因突变检出率差异有统计学意义(P<0.01)。本研究共检出13种类型G6PD基因单一突变型(c.1024 G>T、c.1388 G>A、c.95 A>G、c.1376 G>T、c.592C>T、c.871 G>A、c.519 C>T、c.392G>T、c.493 A>G、c.1004C>A、c.1360C>T、c.383T>C、c.517T>C)和6种复合突变型(c.1376 G>T杂合复合c.95A>G杂合突变、c.1024 G>T杂合复合c.95A>G杂合突变、c.1024 C>T杂合复合c.1388 G>A杂合突变、c.1024 C>T杂合复合c.519C>T杂合突变、c.1376 G>T杂合复合c.1024 C>T杂合突变、c.95A>G杂合复合c.1388 G>A杂合突变)。贵阳地区G6PD缺乏症基因突变类型复杂多样,G6PD突变常见类型为c.1024 C>T、c.1388G>A、c.95 A>G、c.1376G>T这四种类型。结论贵阳地区G6PD基因突变位点具有明显地域性特征,开展G6PD酶活性筛查及相关诊断检测,有利于本地区G6PD缺乏症的筛查、确诊、治疗和防控,有效提高出生人口素质。

Development of a multiplex polymerase chain reaction assay for detection of hepatitis C virus,hepatitis B virus,and human immunodeficiency virus 1

BACKGROUND Hepatitis C virus(HCV),hepatitis B virus(HBV),and human immunodeficiency virus 1(HIV-1)are the most epidemic blood-borne viruses,posing threats to human health and causing economic losses to nations for combating the infection transmission.The diagnostic methodologies that depend on the detection of viral nucleic acids are much more expensive,but they are more accurate than sero-logical testing.AIM To develop a rapid,cost-effective,and accurate diagnostic multiplex polymerase chain reaction(PCR)assay for simultaneous detection of HCV,HBV,and HIV-1.METHODS The design of the proposed PCR assay targets the amplification of a short conserved region featured with a distinguishable melting profile and electro-phoretic molecular weight inside each viral genome.Therefore,this diagnostic method will be appropriate for application in both conventional(combined with electrophoresis)and real-time PCR facilities.Confirmatory in silico investigations were conducted to prove the capability of the approached PCR assay to detect variants of each virus.Then,Egyptian isolates of each virus were subjected to the wet lab examination using the given diagnostic assay.RESULTS The in silico investigations confirmed that the PCR primers can match many viral variants in a multiplex PCR assay.The wet lab experiment proved the efficiency of the assay in distinguishing each viral type through high-resolution melting analysis.Compared to related published assays,the proposed assay in the current study is more sensitive and competitive with many expensive PCR assays.CONCLUSION This study provides a simple,cost-effective,and sensitive diagnostic PCR assay facilitating the detection of the most epidemic blood-borne viruses;this makes the proposed assay promising to be substitutive for the mistakable and cheap serological-based assays.

龟甲配方颗粒的高分辨熔解曲线技术鉴别研究

目的建立一种龟甲配方颗粒高分辨熔解曲线(HRM)技术鉴别方法。方法根据乌龟Chinemys reevesii及其混伪品的细胞色素C氧化酶亚基Ⅰ(cytochrome oxidase subunitⅠ,COI)基因序列上的单核苷酸多态性(single nucleotide polymorphisms,SNP)位点设计鉴别引物,扩增产物直接进行HRM分析,并优化反应体系,根据最佳条件进行适用性验证。结果在模板DNA质量浓度为0.62~374.88 ng/μL、引物浓度为0.1~0.4μmol/L、退火温度为62℃、循环数为45个的条件下,龟甲饮片和配方颗粒的熔解曲线为单峰,其Tm均值分别为(82.39±0.09)、(82.38±0.05)℃,而混伪品和醋龟甲配方颗粒未有扩增。结论该研究建立的高分辨熔解曲线鉴别方法可快速鉴别龟甲原料和配方颗粒的真伪,以及区分其生品和炮制品配方颗粒,为龟甲配方颗粒的质量标准研究提供了理论依据。

探针熔解曲线在耐药结核病快速筛查中的临床应用研究

目的研究探针熔解曲线在耐药结核病快速筛查中的临床应用价值。方法选取2020年1月—2021年3月镇江市第三人民医院收治的378例肺结核患者为研究对象,依次完成传统罗氏固体药物敏感性检测(比例法)、探针熔解曲线技术检测常用的6种药物耐药结果,包含利福平、异烟肼、乙胺丁醇、链霉素、氧氟沙星、阿米卡星,和比例法进行对比,计算探针熔解曲线技术检测6种药物的敏感度、特异度、阳性预测值、阴性预测值、符合率与约登指数。结果与比例法作比较,熔解曲线技术检测利福平耐药性的敏感度、特异度、阳性预测值、阴性预测值、符合率、约登指数分别为91.70%、98.10%、61.10%、99.70%、97.90%、0.898;异烟肼是87.90%、94.20%、59.20%、98.80%、93.65%、0.821;乙胺丁醇是87.50%、97.03%、38.89%、99.72%、96.83%、0.845;链霉素是91.30%、98.19%、87.50%、98.79%、97.35%、0.895;氧氟沙星是94.74%、98.89%、81.82%、99.72%、98.68%、0.936;阿米卡星是80.00%、99.46%、66.67%、99.73%、99.21%、0.795。结论探针熔解曲线在耐药结核病快速筛查中应用,具有较高敏感度及特异度,有利于临床早期识别耐药现象。

Rapid screening for Klinefelter syndrome with a simple high-resolution melting assay： a multicenter study

Klinefelter syndrome （KS） is the set of symptoms that result from the presence of an extra X chromosome in males. Postnatal population-based KS screening will enable timely diagnosis of this common chromosomal disease, providing the opportunity for early intervention and therapy at the time point when they are most effective and may prevent later symptoms or complications. Therefore, through this study, we introduced a simple high-resolution melting （HRM） assay for KS screening and evaluated its clinical sensitivity and specificity in three medical centers using 1373 clinical blood samples. The HRM assay utilized a single primer pair to simultaneously amplify specific regions in zinc finger protein, X-linked （ZFX） and zinc finger protein, Y-linked （ZFY）. In cases of KS, the ratios of ZFX/ZFYare altered compared to those in normal males. As a result, the specific melting profiles differ and can be differentiated during data analysis. This HRM assay displayed high analytical specificity over a wide range of template DNA amounts （5 ng-50 ng） and reproducibility, high resolution for detecting KS mosaicism, and high clinical sensitivity （100%） and specificity （98.1%）. Moreover, the HRM assay was rapid （2 h per run）, inexpensive （0.2 USD per sample）, easy to perform and automatic, and compatible with both whole blood samples and dried blood spots. Therefore, this HRM assay is an ideal postnatal population-based KS screening tool that can be used for different age groups.

Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO_2

Ab initio two-phase molecular dynamics simulations were performed on silica at pressures of 20-160 GPa and temperatures of 2 500-6 000 K to examine its solid-liquid phase boundary. Results indicate a melting temperature （Tin） of 5 900 K at 135 GPa. This is 1 100 K higher than the temperature considered for the core-mantle boundary （CMB） of about 3 800 K. The calculated melting temperature is fairly consistent with classical MD （molecular dynamics） simulations. For liquid silica, the O-O coordination number is found to be 12 along the Tm and is almost unchanged with increasing pressure. The self-diffusion coefficients of O and Si atoms are determined to be 1.3×10^-9-3.3×10^-9 m2/s, and the viscosity is 0.02-0.03 Pa＇s along the Tin. We find that these transport properties depend less on pressure in the wide range up of more than 135 GPa. The eutectic temperatures in the MgO-SiO2 systems were evaluated and found to be 700 K higher than the CMB temperature, though they would decrease considerably in more realistic mantle compositions.

STUDIES ON MELTING CURVE OF NOBLE METAL

Ⅰ. INTRODUCTIONMelting of metals is a very interesting physical phenomenon. The exact theoretical calculation about it involves the calculation of free energy in solid and liquid states, which is very difficult. Starting from the vibration amplitude of atoms, Lindemann gave the well-known melting law, which has been extensively applied to the melting phenomenon. The depen-

Multi-locus identification of Psilocybe cubensis by high-resolution melting(HRM)

Hallucinogenic mushroom is a kind of toxic strain containing psychoactive tryptamine substances such as psilocybin,psilocin and ibotenic acid,etc.The mushrooms containing hallucinogenic components are various,widely distributed and lack of standard to define,which made a great challenge to identification.Traditional identification methods,such as morphology and toxicology analysis,showed shortcomings in old or processed samples,while the DNA-based identification of hallucinogenic mushrooms would allow to identify these samples due to the stability of DNA.In this paper,four primer sets are designed to target Psilocybe cubensis DNA for increasing resolution of present identification method,and the target markers include largest subunit of RNA polymerase II(marked as PC-R1),psilocybin-related phosphotransferase gene(marked as PC-PT),glyceraldehyde 3-phosphate dehydrogenase(marked as PC-3)and translation EF1α(marked as PC-EF).Real-time PCR with high-resolution melting(HRM)assay were used for the differentiation of the fragments amplified by these primer sets,which were tested for specificity,reproducibility,sensitivity,mixture analysis and multiplex PCR.It was shown that the melting temperatures of PC-R1,PC-PT,PC-3 and PC-EF of P.cubensis were(87.93±0.12)℃,(82.21±0.14)℃,(79.72±0.12)℃ and(80.11±0.19)℃ in our kinds of independent experiments.Significant HRM characteristic can be shown with a low concentration of 62.5pg/µL DNA sample,and P.cubensis could be detected in mixtures with Homo sapiens or Cannabis sativa.In summary,the method of HRM analysis can quickly and specifically distinguish P.cubensis from other species,which could be utilized for forensic science,medical diagnosis and drug trafficking cases.

4例ABO和Rh血型嵌合体的血清学及分子生物学基础研究

目的研究血型嵌合体的血清学特征分子生物学确认方法。方法对4例医院输血科送检做ABO和RhD血型的患者,进行ABO和Rh血型鉴定、毛细管离心分离新生红细胞、吸收试验、DTT处理凝集红细胞试验,同时对患者1的血样进行分子生物学研究。结果患者1:ABO血型为AB/B型嵌合,Rh血型为RhCE基因嵌合;患者2:Rh血型为RhD基因嵌合;患者3:ABO血型为AB/B型嵌合,Rh血型为RhD基因嵌合;患者4:ABO血型为O/B型嵌合,Rh血型为RhCE基因嵌合。结论在血型血清学上,排除患者有近期输血史,同时又不存在使患者抗原减弱的疾病情况下,ABO和Rh血型出现混合外观现象是其主要特征,实验人员可依据此怀疑患者是有血型嵌合体的可能通过血清学和分子生物学方法进行确认。

棕榈油基抗融型冰淇淋油脂的研制和应用

以滑动熔点、固体脂肪含量曲线和熔化-结晶行为为考察指标,采用物理混合和酶法酯交换两种方式制备棕榈基抗融型冰淇淋油脂,并对油脂制备工艺进行优化;然后利用所得油脂制作出冰淇淋,并对冰淇淋的膨胀率、融化率和感官评价进行分析。结果表明,在椰子油:40℃棕榈油中间分提物混合质量比为5:5,脂肪酶Lipozyme TL IM添加量为10%,反应时间为4 h,反应温度为60℃条件下的酯交换油脂显示出令人满意的熔点、SFC曲线和熔融结晶曲线。利用该油脂制作的冰淇淋融化率低于50%,膨胀率为58.36%,感官评价得分为81.6分,高于物理混合组。本文通过酶法酯交换技术获得的棕榈基抗融型冰淇淋油脂,显著提高了冰淇淋产品的热稳定性和抗融性,为抗融型冰淇淋专用油脂的开发提供理论依据。

基于PCR-HRM的水稻氮高效基因NRT1.1B功能标记开发及应用

水稻对氮肥的高效与合理利用是发展绿色农业的重要保障。培育含有氮高效基因的水稻品种,是提高氮肥利用率最经济有效的途径。本研究开发了一个用于HRM(高分辨率熔解曲线)高通量检测硝酸盐转运蛋白基因NRT1.1B的分子功能标记。利用此标记对78份山东地方水稻品种进行NRT1.1B基因分型,发现有13个水稻品种为含有NRT1.1B的高效单倍型,表明NRT1.1B在山东省水稻品种中分布较少。利用测序分析验证,测序结果与本标记分型结果一致。可见,本研究开发的功能标记能够快速准确鉴定出NRT1.1B基因型,可为筛选和培育氮高效水稻新品种提供有力的技术支撑。