The mechanical sensitivity, the critical thickness of detonation wave propagation and detonation velocity of desensitized PETN film were studied by experiments. The relationship between the mass of desensitizer paraff...The mechanical sensitivity, the critical thickness of detonation wave propagation and detonation velocity of desensitized PETN film were studied by experiments. The relationship between the mass of desensitizer paraffin wax and the friction sensitivity of desensitized PETN film was tested. According to the microstructure of film, the function of desensitizer was explained. It was proved that the explosive film could make explosive element micromation and kept its inherence properties by the result of testing the propagating critical dimension of the desensitized PETN film detonation wave. The explosive velocity of confined desensitized PETN film was tested by the multiplex optical fibre..展开更多
Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accident...Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.展开更多
Objective: The purpose of this study was to investigate the effects of desensitized nicotinic receptors(n ACh Rs) on striatal dopaminergic system in the hemiparkinsonian rats treated with 6-hydroxydopamine(6-OHDA). Me...Objective: The purpose of this study was to investigate the effects of desensitized nicotinic receptors(n ACh Rs) on striatal dopaminergic system in the hemiparkinsonian rats treated with 6-hydroxydopamine(6-OHDA). Methods: We examined the effects of desensitized n ACh Rs on the levels of dopamine(DA) and its metabolites, m RNA expression of dopamine receptor D1,D2 and monoamine oxidase B(MAO-B) in the striatum of 6-OHDA-lesioned rats using high-performance liquid chromatography and reverse transcription-polymerase chain reaction. Results: The results showed that n ACh Rs desensitization following repeated nicotine stimulation could reverse significantly the decrease of striatal DA and its metabolites levels and the increase in DA turnover in lesioned side striatum of hemiparkinsonian rats. Dopamine D1 receptor m RNA expression increased significantly, whereas dopamine D2 receptor m RNA expression remained unchanged in lesioned side striatum of nicotine-treated rats compared to 6-OHDA-lesioned rats when n ACh Rs were desensitized. Meanwhile, nicotine-treated rats displayed a significant decrease in MAO-B m RNA expression in lesioned side striatum compared to 6-OHDA-lesioned rats after n ACh Rs desensitization. Conclusion: These results suggest that n ACh Rs desensitization could promote DA level, upregulate dopamine D1 receptor expression and downregulate MAO-B expression in striatum of hemiparkinsonian rats.展开更多
Desensitization is a process characterized by the loss of cellular response to an agonist when this is present for a long time. α<sub>1D</sub>-adrenergic receptor (α<sub>1D</sub>-AR) desensit...Desensitization is a process characterized by the loss of cellular response to an agonist when this is present for a long time. α<sub>1D</sub>-adrenergic receptor (α<sub>1D</sub>-AR) desensitization is important since this receptor is involved in the contraction of large caliber arteries, such as the aorta. The aim of this research was to evaluate the desensitization of α<sub>1D</sub>-AR due to the endogenous release of norepinephrine in cultured rat aorta. Wistar rat aorta was incubated for 2 h or 24 h in DMEM at 37°C, and then subjected to isometric tension and the action of added norepinephrine, in concentration-response curve (CRC). In some experiments, BMY-7378 (α<sub>1D</sub>-AR antagonist) or 5-methylurapidil (α<sub>1A</sub>-AR antagonist) was used to identify the α<sub>1</sub>-AR involved in the response, or BMY-7378 to protect the α<sub>1D</sub>-AR from desensitization. Results showed that α<sub>1D</sub>-AR was desensitized when the aorta was incubated for 24 h, since the CRC to exogenous norepinephrine showed lower maximal contraction and the curve was displaced to the right, indicating that the receptor involved in contraction was not the α<sub>1D</sub>-AR, as compared to the aorta incubated 2 h. The receptor stimulated by norepinephrine at 24 h was neither the α<sub>1A</sub>-AR, as shown by the lack of displacement of the curve by 5-methylurapidil, but rather it seems that α<sub>1B</sub>-AR is inducing contraction. When the aorta was incubated with BMY-7378 for 24 h, the α<sub>1D</sub>-AR antagonist protected the receptor from desensitization. Endogenous norepinephrine desensitizes α<sub>1D</sub>-AR in the cultured aorta, and the α<sub>1D</sub>-AR is protected by BMY-7378.展开更多
Objective:To establish and verify aβ_(2)-AR desensitization asthma mice model.Methods:A total of 30 SPF male BALB/c mice were randomly divided into blank group,the common asthma group,andβ_(2)-AR desensitization ast...Objective:To establish and verify aβ_(2)-AR desensitization asthma mice model.Methods:A total of 30 SPF male BALB/c mice were randomly divided into blank group,the common asthma group,andβ_(2)-AR desensitization asthma model group.Asthma model was established,and on this basis,the method of atom-izing inhalation and intraperitoneal injections of salbutamol was used to prepareβ_(2)-AR desensitization asthma model.After the last stimulation on the 21st day of modeling,the airway resistance of mice was measured.ELISA was used to detect the content of serum IgE;HE staining was used to observe the lung organization degree of infla-mmatory cell infiltration;Western blot method was used to detect theβ_(2)-AR content in lung tissue,RT-PCR was used to detect theβ_(2)-ARmRNA expressionin lung tissue.Results:Compared with the blank group,as acetyl choline(Mch)levels increased,groups of OVA induced airway resistance increases;but theβ_(2)-AR desensitization asthma model group increased airway resistance was more significant(P<0.05);compared with the blank group,IgE levels of common asthma group andβ_(2)-AR desensitization asthma model group elevated(P<0.01).The pathological histology observation found theβ_(2)-AR desensitization asthma airway inflammation infiltration in mice,the excessive mucus secretion and collagen deposition,and the pathological performance obviously increase compared with the common asthma group;β_(2)-AR content in the lung tissue ofβ_(2)-AR desensitization asthma model in mice,β_(2)-AR mRNA expression level in the blank group and common asthma model group were significantly decreased(P<0.05).Conclusion:Theβ_(2)-AR desensitization asthma mouse model was successfully established,and the buildingcycle was short.展开更多
目的系统评价利妥昔单抗快速脱敏治疗的有效性和安全性。方法检索PubMed、Embase、Cochrane、Web of Science、Scopus、中国知识基础设施工程网(CNKI)、万方数据库数字化期刊和重庆维普中文科技期刊数据库,检索时限均为建库至2023年2月...目的系统评价利妥昔单抗快速脱敏治疗的有效性和安全性。方法检索PubMed、Embase、Cochrane、Web of Science、Scopus、中国知识基础设施工程网(CNKI)、万方数据库数字化期刊和重庆维普中文科技期刊数据库,检索时限均为建库至2023年2月。由2位评价员独立筛选文献、提取数据,并评价纳入文献的质量,对结果数据进行描述性分析或统计性分析。系统评价方案已在PROSPERO注册(CRD:42022306557)。结果纳入25项研究(11个病例报告和14个病例系列),共计138例患者进行脱敏治疗,129例脱敏成功(即至少完成一次目标剂量给药)。脱敏前预处理方案为H1、H2受体拮抗剂,糖皮质激素,镇静剂,NSAIDs和对乙酰氨基酚等药物中2种或以上联合,88%的研究预处理分别包含H1受体拮抗剂或糖皮质激素。16项(64.0%)研究报告患者脱敏前皮试情况,皮肤点刺试验(n=16)和皮内试验(n=59)阳性率分别为12.50%、49.15%。17项研究(68.0%)采用3袋-12步法快速脱敏方案,其余为4袋-16步或2袋-8步等多种方法;利妥昔单抗初始给药浓度(即第一袋脱敏药液浓度)为1/10 X-1/10000 X,第一步输注速率基本为1.5~5 mL·min^(-1),单次脱敏总时长4~10.5 h。23项(92%)研究报告患者脱敏过程中变态反应发生情况,其中5项研究未发生变态反应、18项研究中大部分患者在给予对症处理或修改脱敏方案后完成脱敏治疗。结论当前证据表明,利妥昔单抗快速脱敏治疗具有一定的有效性和安全性,但目前缺乏具体的操作性强的高质量证据或执行标准,有待更多大样本、多中心的研究在脱敏前皮试、预处理、个体化脱敏步骤和脱敏过程中过敏反应处理等方面进一步探索。展开更多
目的:牙本质敏感症(dentin hypersensitivity,DH)作为口腔中常见的一种症状和疾病,可能对患者的生活质量产生较大影响,本研究通过体外实验比较Regesi生物活性材料、Gluma脱敏剂和可乐丽菲露Clearfil SE Bond两步法粘接剂对牙本质小管封...目的:牙本质敏感症(dentin hypersensitivity,DH)作为口腔中常见的一种症状和疾病,可能对患者的生活质量产生较大影响,本研究通过体外实验比较Regesi生物活性材料、Gluma脱敏剂和可乐丽菲露Clearfil SE Bond两步法粘接剂对牙本质小管封闭程度及耐久性的差异,为其用于牙本质敏感症的治疗提供数据支持。方法:体外实验中,用离体牙制作牙本质敏感模型,根据脱敏材料的不同进行随机分组(对照组:人工唾液组;A组:Regesi组;B组:Gluma组;C组:Clearfil SEBond组),通过SEM观察脱敏剂作用后,4组牙本质敏感模型的形貌及牙本质小管封闭效果,分析对比其脱敏效果的差异,并通过耐磨性实验,分析材料间脱敏效果持久性之间的差异及表面硬度的差异。结果:SEM观察可见A、B、C组的牙本质小管封闭效果均优于对照组,结果有统计学差异,其中A组封闭效果最好,较其他两组有统计学差异。耐磨性实验前后,A组的表面硬度均高于其他三组,结果有统计学差异。结论:Regesi生物活性材料较Gluma脱敏剂和Clearfil SE Bond两步法粘接剂对牙本质小管的封闭程度及耐久性能更佳,能更好地治疗牙本质敏感症。展开更多
奥沙利铂是多种恶性肿瘤治疗的基石药物。超敏反应是奥沙利铂令人困扰的不良反应之一,可能危及患者生命,常迫使医师停用奥沙利铂,转寻其他替代方案,而这些替代方案可能效果更差、耐受性更低和(或)价格更昂贵。奥沙利铂超敏反应主要表现...奥沙利铂是多种恶性肿瘤治疗的基石药物。超敏反应是奥沙利铂令人困扰的不良反应之一,可能危及患者生命,常迫使医师停用奥沙利铂,转寻其他替代方案,而这些替代方案可能效果更差、耐受性更低和(或)价格更昂贵。奥沙利铂超敏反应主要表现为经典的Ⅰ型过敏反应,另外还包含细胞因子释放反应及混合型。临床上最关注的是严重过敏反应的管理以及针对发生超敏反应后奥沙利铂再挑战的问题。因此,本专家组基于国内外循证医学证据,结合临床实践经验,对奥沙利铂超敏反应的定义、临床特征、诊断、分类与分级标准、处理以及再挑战进行充分的评估与讨论,最终形成《奥沙利铂超敏反应全程管理中国专家共识(2024年版)》,以便进一步规范对奥沙利铂超敏反应的全程管理。本共识已在国际实践指南注册与透明化平台(Practice guideline REgistration for transPAREncy,PREPARE)上注册,注册编号为PREPARE-2024CN371。展开更多
文摘The mechanical sensitivity, the critical thickness of detonation wave propagation and detonation velocity of desensitized PETN film were studied by experiments. The relationship between the mass of desensitizer paraffin wax and the friction sensitivity of desensitized PETN film was tested. According to the microstructure of film, the function of desensitizer was explained. It was proved that the explosive film could make explosive element micromation and kept its inherence properties by the result of testing the propagating critical dimension of the desensitized PETN film detonation wave. The explosive velocity of confined desensitized PETN film was tested by the multiplex optical fibre..
基金supported in part by the National Natural Science Foundation of China(No.22075146)。
文摘Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.
基金supported by a grant from the National Natural Science Foundations of China(30371641)
文摘Objective: The purpose of this study was to investigate the effects of desensitized nicotinic receptors(n ACh Rs) on striatal dopaminergic system in the hemiparkinsonian rats treated with 6-hydroxydopamine(6-OHDA). Methods: We examined the effects of desensitized n ACh Rs on the levels of dopamine(DA) and its metabolites, m RNA expression of dopamine receptor D1,D2 and monoamine oxidase B(MAO-B) in the striatum of 6-OHDA-lesioned rats using high-performance liquid chromatography and reverse transcription-polymerase chain reaction. Results: The results showed that n ACh Rs desensitization following repeated nicotine stimulation could reverse significantly the decrease of striatal DA and its metabolites levels and the increase in DA turnover in lesioned side striatum of hemiparkinsonian rats. Dopamine D1 receptor m RNA expression increased significantly, whereas dopamine D2 receptor m RNA expression remained unchanged in lesioned side striatum of nicotine-treated rats compared to 6-OHDA-lesioned rats when n ACh Rs were desensitized. Meanwhile, nicotine-treated rats displayed a significant decrease in MAO-B m RNA expression in lesioned side striatum compared to 6-OHDA-lesioned rats after n ACh Rs desensitization. Conclusion: These results suggest that n ACh Rs desensitization could promote DA level, upregulate dopamine D1 receptor expression and downregulate MAO-B expression in striatum of hemiparkinsonian rats.
文摘Desensitization is a process characterized by the loss of cellular response to an agonist when this is present for a long time. α<sub>1D</sub>-adrenergic receptor (α<sub>1D</sub>-AR) desensitization is important since this receptor is involved in the contraction of large caliber arteries, such as the aorta. The aim of this research was to evaluate the desensitization of α<sub>1D</sub>-AR due to the endogenous release of norepinephrine in cultured rat aorta. Wistar rat aorta was incubated for 2 h or 24 h in DMEM at 37°C, and then subjected to isometric tension and the action of added norepinephrine, in concentration-response curve (CRC). In some experiments, BMY-7378 (α<sub>1D</sub>-AR antagonist) or 5-methylurapidil (α<sub>1A</sub>-AR antagonist) was used to identify the α<sub>1</sub>-AR involved in the response, or BMY-7378 to protect the α<sub>1D</sub>-AR from desensitization. Results showed that α<sub>1D</sub>-AR was desensitized when the aorta was incubated for 24 h, since the CRC to exogenous norepinephrine showed lower maximal contraction and the curve was displaced to the right, indicating that the receptor involved in contraction was not the α<sub>1D</sub>-AR, as compared to the aorta incubated 2 h. The receptor stimulated by norepinephrine at 24 h was neither the α<sub>1A</sub>-AR, as shown by the lack of displacement of the curve by 5-methylurapidil, but rather it seems that α<sub>1B</sub>-AR is inducing contraction. When the aorta was incubated with BMY-7378 for 24 h, the α<sub>1D</sub>-AR antagonist protected the receptor from desensitization. Endogenous norepinephrine desensitizes α<sub>1D</sub>-AR in the cultured aorta, and the α<sub>1D</sub>-AR is protected by BMY-7378.
基金General Projects of National Natural Science Fund(81873338)Key Scientific and Technological Projects in Henan Province(202102310491)Training Subjects of Leading Talents in the Department of Traditional Chinese Medicine in Henan Province(Yuweizhongyihan[2021]No.8)。
文摘Objective:To establish and verify aβ_(2)-AR desensitization asthma mice model.Methods:A total of 30 SPF male BALB/c mice were randomly divided into blank group,the common asthma group,andβ_(2)-AR desensitization asthma model group.Asthma model was established,and on this basis,the method of atom-izing inhalation and intraperitoneal injections of salbutamol was used to prepareβ_(2)-AR desensitization asthma model.After the last stimulation on the 21st day of modeling,the airway resistance of mice was measured.ELISA was used to detect the content of serum IgE;HE staining was used to observe the lung organization degree of infla-mmatory cell infiltration;Western blot method was used to detect theβ_(2)-AR content in lung tissue,RT-PCR was used to detect theβ_(2)-ARmRNA expressionin lung tissue.Results:Compared with the blank group,as acetyl choline(Mch)levels increased,groups of OVA induced airway resistance increases;but theβ_(2)-AR desensitization asthma model group increased airway resistance was more significant(P<0.05);compared with the blank group,IgE levels of common asthma group andβ_(2)-AR desensitization asthma model group elevated(P<0.01).The pathological histology observation found theβ_(2)-AR desensitization asthma airway inflammation infiltration in mice,the excessive mucus secretion and collagen deposition,and the pathological performance obviously increase compared with the common asthma group;β_(2)-AR content in the lung tissue ofβ_(2)-AR desensitization asthma model in mice,β_(2)-AR mRNA expression level in the blank group and common asthma model group were significantly decreased(P<0.05).Conclusion:Theβ_(2)-AR desensitization asthma mouse model was successfully established,and the buildingcycle was short.
文摘目的:牙本质敏感症(dentin hypersensitivity,DH)作为口腔中常见的一种症状和疾病,可能对患者的生活质量产生较大影响,本研究通过体外实验比较Regesi生物活性材料、Gluma脱敏剂和可乐丽菲露Clearfil SE Bond两步法粘接剂对牙本质小管封闭程度及耐久性的差异,为其用于牙本质敏感症的治疗提供数据支持。方法:体外实验中,用离体牙制作牙本质敏感模型,根据脱敏材料的不同进行随机分组(对照组:人工唾液组;A组:Regesi组;B组:Gluma组;C组:Clearfil SEBond组),通过SEM观察脱敏剂作用后,4组牙本质敏感模型的形貌及牙本质小管封闭效果,分析对比其脱敏效果的差异,并通过耐磨性实验,分析材料间脱敏效果持久性之间的差异及表面硬度的差异。结果:SEM观察可见A、B、C组的牙本质小管封闭效果均优于对照组,结果有统计学差异,其中A组封闭效果最好,较其他两组有统计学差异。耐磨性实验前后,A组的表面硬度均高于其他三组,结果有统计学差异。结论:Regesi生物活性材料较Gluma脱敏剂和Clearfil SE Bond两步法粘接剂对牙本质小管的封闭程度及耐久性能更佳,能更好地治疗牙本质敏感症。
文摘奥沙利铂是多种恶性肿瘤治疗的基石药物。超敏反应是奥沙利铂令人困扰的不良反应之一,可能危及患者生命,常迫使医师停用奥沙利铂,转寻其他替代方案,而这些替代方案可能效果更差、耐受性更低和(或)价格更昂贵。奥沙利铂超敏反应主要表现为经典的Ⅰ型过敏反应,另外还包含细胞因子释放反应及混合型。临床上最关注的是严重过敏反应的管理以及针对发生超敏反应后奥沙利铂再挑战的问题。因此,本专家组基于国内外循证医学证据,结合临床实践经验,对奥沙利铂超敏反应的定义、临床特征、诊断、分类与分级标准、处理以及再挑战进行充分的评估与讨论,最终形成《奥沙利铂超敏反应全程管理中国专家共识(2024年版)》,以便进一步规范对奥沙利铂超敏反应的全程管理。本共识已在国际实践指南注册与透明化平台(Practice guideline REgistration for transPAREncy,PREPARE)上注册,注册编号为PREPARE-2024CN371。
