首页 > 最新文献

Journal of physical chemistry & biophysics最新文献

英文 中文
Radiological Impacts of Natural Radioactivity in Locally Produced Tobacco Products in Oyo State, Nigeria 尼日利亚奥约州当地生产的烟草制品中天然放射性的辐射影响
Pub Date : 2018-01-01 DOI: 10.4172/2161-0398.1000262
Akinyose Fc, P. Tchokossa, Orosun Mm, Mark Ib, K. K. Ochommadu, S. Oluyide
Radionuclides are found naturally in air, water and soil. They are even found in vegetation, consumer products and in human body. Everyone on the planet is exposed to some background level of ionizing radiation through external exposures that occurs as a result of irradiation, and internal exposures that occurs as a result of ingestion and inhalation. Studies have shown that tobacco contains minute quantities of radioisotopes from uranium and thorium-decay series which are radioactive and carcinogenic. Tobacco product increases both external and internal exposure due to these radioisotopes. In fact, tobacco products have been considered to be one of the most significant causes of lung cancer. Owing to the large-scale consumption of tobacco in Nigeria at the present time, locally produced tobacco products in Nigeria were collected from the market and the naturally-occurring 238U and 232Th decay series, as well as non-series decay 40K in these products were measured using γ-ray spectrometer. The radiological impacts of the radionuclides in these products were assessed from their specific activities. The average values of the absorbed dose rate were 19.72 and 17.59 nGy h-1 for snuff and cigarette products respectively. The average values of the effective doses due to daily inhalation of smoke by consumers from one (1) stick of cigarette and one (1) wrap of snuff products were 66.62 and 592.32 μSv yr-1 respectively. Similarly, the values of the radium equivalent activity index for snuff and cigarette samples were 40.95 and 38.95 Bq kg-1 respectively. Also, the external radiation hazard index was 0.12 and 0.11 for snuff and cigarette samples respectively while the internal radiation hazard index was 0.17 and 0.15 for the two samples respectively. The average excess lifetime cancer risk (× 10-3) values for daily inhalation of smoke from one (1) stick of cigarette and one (1) wrap of snuff were 0.23 and 2.07 × 10-3 respectively. The estimated values of some of these parameters were found to be lower than the recommended limit by UNSCEAR (2000). However, the effective dose poses a serious health risk to addicted consumers of the product and passive smokers in the environment when three (3) or more wraps of snuff and one (1) or more packs of cigarette products are consumed daily. The mean excess lifetime cancer risks values estimated were also much higher than the recommended limits by UNSCEAR (2000). This then makes the risk of suffering cancer and other radiation injuries to be high.
放射性核素自然存在于空气、水和土壤中。它们甚至存在于植物、消费品和人体中。地球上的每个人都暴露在电离辐射的背景水平下,这是由于辐照造成的外部暴露,以及由于摄入和吸入造成的内部暴露。研究表明,烟草含有微量的铀和钍衰变系列的放射性同位素,这些放射性同位素具有放射性和致癌性。由于这些放射性同位素,烟草制品增加了外部和内部暴露。事实上,烟草制品被认为是导致肺癌的最重要原因之一。由于目前尼日利亚烟草消费规模较大,我们从市场上收集尼日利亚当地生产的烟草制品,利用γ射线光谱仪测量了这些产品中天然存在的238U和232Th衰变系列以及非系列衰变40K。根据这些产品中放射性核素的具体活性,对其放射性影响进行了评估。鼻烟和卷烟产品的吸收剂量率平均值分别为19.72和17.59 nGy h-1。消费者每日从一根香烟和一包鼻烟中吸入烟雾的有效剂量平均值分别为66.62和592.32 μSv -1。同样,鼻烟和卷烟样品的镭当量活度指数分别为40.95和38.95 Bq kg-1。鼻烟和卷烟样品的外辐射危害指数分别为0.12和0.11,内辐射危害指数分别为0.17和0.15。每日吸1支香烟和1包鼻烟的平均终生癌症风险(× 10-3)值分别为0.23和2.07 × 10-3。发现其中一些参数的估计值低于科委会(2000年)建议的限度。然而,当每天消耗三(3)包或更多的鼻烟和一(1)包或更多的卷烟产品时,有效剂量对该产品的成瘾消费者和环境中的被动吸烟者构成严重的健康风险。估计的平均超额终身癌症风险值也远高于联合国科委会(2000年)建议的限值。这使得患癌症和其他辐射伤害的风险很高。
{"title":"Radiological Impacts of Natural Radioactivity in Locally Produced Tobacco Products in Oyo State, Nigeria","authors":"Akinyose Fc, P. Tchokossa, Orosun Mm, Mark Ib, K. K. Ochommadu, S. Oluyide","doi":"10.4172/2161-0398.1000262","DOIUrl":"https://doi.org/10.4172/2161-0398.1000262","url":null,"abstract":"Radionuclides are found naturally in air, water and soil. They are even found in vegetation, consumer products and in human body. Everyone on the planet is exposed to some background level of ionizing radiation through external exposures that occurs as a result of irradiation, and internal exposures that occurs as a result of ingestion and inhalation. Studies have shown that tobacco contains minute quantities of radioisotopes from uranium and thorium-decay series which are radioactive and carcinogenic. Tobacco product increases both external and internal exposure due to these radioisotopes. In fact, tobacco products have been considered to be one of the most significant causes of lung cancer. Owing to the large-scale consumption of tobacco in Nigeria at the present time, locally produced tobacco products in Nigeria were collected from the market and the naturally-occurring 238U and 232Th decay series, as well as non-series decay 40K in these products were measured using γ-ray spectrometer. The radiological impacts of the radionuclides in these products were assessed from their specific activities. The average values of the absorbed dose rate were 19.72 and 17.59 nGy h-1 for snuff and cigarette products respectively. The average values of the effective doses due to daily inhalation of smoke by consumers from one (1) stick of cigarette and one (1) wrap of snuff products were 66.62 and 592.32 μSv yr-1 respectively. Similarly, the values of the radium equivalent activity index for snuff and cigarette samples were 40.95 and 38.95 Bq kg-1 respectively. Also, the external radiation hazard index was 0.12 and 0.11 for snuff and cigarette samples respectively while the internal radiation hazard index was 0.17 and 0.15 for the two samples respectively. The average excess lifetime cancer risk (× 10-3) values for daily inhalation of smoke from one (1) stick of cigarette and one (1) wrap of snuff were 0.23 and 2.07 × 10-3 respectively. The estimated values of some of these parameters were found to be lower than the recommended limit by UNSCEAR (2000). However, the effective dose poses a serious health risk to addicted consumers of the product and passive smokers in the environment when three (3) or more wraps of snuff and one (1) or more packs of cigarette products are consumed daily. The mean excess lifetime cancer risks values estimated were also much higher than the recommended limits by UNSCEAR (2000). This then makes the risk of suffering cancer and other radiation injuries to be high.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75620967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
QSPR and DFT Studies on the Melting Point of Carbocyclic Nitroaromatic Compounds 碳环硝基芳香化合物熔点的QSPR和DFT研究
Pub Date : 2017-12-30 DOI: 10.4172/2161-0398.1000245
B. Elidrissi, A. Ousaa, M. Ghamali, Samir CHTITA, M. A. Ajana, M. Bouachrine, T. Lakhlifi
A quantitative structure-property relationship (QSPR) study was performed to predict the melting points of 60 carbocyclic nitroaromatic compounds using the electronic and topologic descriptors computed respectively, with ACD/ ChemSketch and Gaussian 03W programs. The structures of all 60 compounds were optimized using the hybrid density functional theory (DFT) at the B3LYP/6-31G(d) level of theory. In both approaches, 50 compounds were assigned as the training set and the rest as the test set. These compounds were analyzed by the principal components analysis (PCA) method, a descendant multiple linear regression (MLR) analyses and an artificial neural network (ANN). The robustness of the obtained models was assessed by leave-many-out cross-validation, and external validation through test set. This study shows that the PCA and MLR have served also to predict melting point and some other physicochemical properties, but when compared with the results given by the ANN (R=0.997), we realized that the predictions fulfilled by this latter were more effective and much better than other models.
利用ACD/ ChemSketch和Gaussian 03W程序分别计算电子描述符和拓扑描述符,对60种碳环硝基芳香族化合物的熔点进行了定量构效关系(QSPR)研究。在B3LYP/6-31G(d)理论水平上,利用杂化密度泛函理论(DFT)对60个化合物进行了结构优化。在这两种方法中,50种化合物被指定为训练集,其余的作为测试集。通过主成分分析(PCA)、后代多元线性回归(MLR)和人工神经网络(ANN)对这些化合物进行分析。通过留多交叉验证和测试集外部验证来评估模型的稳健性。本研究表明,PCA和MLR也可以用于预测熔点和其他一些物理化学性质,但与ANN给出的结果(R=0.997)相比,我们意识到后者的预测更有效,比其他模型要好得多。
{"title":"QSPR and DFT Studies on the Melting Point of Carbocyclic Nitroaromatic Compounds","authors":"B. Elidrissi, A. Ousaa, M. Ghamali, Samir CHTITA, M. A. Ajana, M. Bouachrine, T. Lakhlifi","doi":"10.4172/2161-0398.1000245","DOIUrl":"https://doi.org/10.4172/2161-0398.1000245","url":null,"abstract":"A quantitative structure-property relationship (QSPR) study was performed to predict the melting points of 60 carbocyclic nitroaromatic compounds using the electronic and topologic descriptors computed respectively, with ACD/ ChemSketch and Gaussian 03W programs. The structures of all 60 compounds were optimized using the hybrid density functional theory (DFT) at the B3LYP/6-31G(d) level of theory. In both approaches, 50 compounds were assigned as the training set and the rest as the test set. These compounds were analyzed by the principal components analysis (PCA) method, a descendant multiple linear regression (MLR) analyses and an artificial neural network (ANN). The robustness of the obtained models was assessed by leave-many-out cross-validation, and external validation through test set. This study shows that the PCA and MLR have served also to predict melting point and some other physicochemical properties, but when compared with the results given by the ANN (R=0.997), we realized that the predictions fulfilled by this latter were more effective and much better than other models.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79763691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Specific Heat of Solution of HCl-NaOH Reaction by a Simple Handmade Calorimeter 用简易手工量热计测定盐酸-氢氧化钠反应溶液比热
Pub Date : 2017-12-01 DOI: 10.4172/2161-0398.1000261
M. Fazal-ur-Rahman, Hafiz Zeshan Haider
A research study was performed by couple of students under the research project of bachelor in chemistry. The main goal to perform this project was to determine the changes in temperature of solution when an acid and a base were mixed together inside the cups of handmade calorimeter and their reaction was proceeded under the lab conditions and to determine either reaction would be exothermic or endothermic. Basically, from these changes in temperature of solution, the specific Heat of solution or Heat of reaction was determining. Temperature changes were observed using analytical thermometer with stop watch and all changes were noted on datasheet, while after completion of the whole experimental work, a thermodynamic equation of specific Heat was applied to calculate the Specific Heat of solution mathematically in numeric value which was 3214.72476 J or 3.21472 KJ. It was seen that as the base was mixed into acid, the temperature of solution was increased to maximum rapidly showing the exothermic reaction. After reaching to maximum range, the temperature decreased gradually to its minimum range being constant and consistent. The consistent temperature range terminated the reaction. All variations in temperature ranges were recorded very carefully and a table with a graph showing all ups and downs in temperature ranges was drawn on MS Excel Data Sheet.
在化学学士的研究项目下,一对夫妇进行了一项研究研究。执行这个项目的主要目标是确定当酸和碱在手工量热计杯中混合在一起并在实验室条件下进行反应时溶液温度的变化,并确定反应是放热的还是吸热的。基本上,从这些溶液温度的变化,决定了溶液的比热或反应热。使用带秒表的分析温度计观察温度变化,并将所有变化记录在数据表上,而在整个实验工作完成后,应用热力学比热方程数学计算溶液比热,其数值为3214.72476 J或3.21472 KJ。可以看出,当碱与酸混合时,溶液温度迅速升高到最大值,表现为放热反应。在达到最大范围后,温度逐渐下降到恒定一致的最小范围。一致的温度范围终止了反应。所有温度范围的变化都非常仔细地记录下来,并在MS Excel数据表上绘制了一个图表,显示温度范围的所有起伏。
{"title":"Specific Heat of Solution of HCl-NaOH Reaction by a Simple Handmade Calorimeter","authors":"M. Fazal-ur-Rahman, Hafiz Zeshan Haider","doi":"10.4172/2161-0398.1000261","DOIUrl":"https://doi.org/10.4172/2161-0398.1000261","url":null,"abstract":"A research study was performed by couple of students under the research project of bachelor in chemistry. The main goal to perform this project was to determine the changes in temperature of solution when an acid and a base were mixed together inside the cups of handmade calorimeter and their reaction was proceeded under the lab conditions and to determine either reaction would be exothermic or endothermic. Basically, from these changes in temperature of solution, the specific Heat of solution or Heat of reaction was determining. Temperature changes were observed using analytical thermometer with stop watch and all changes were noted on datasheet, while after completion of the whole experimental work, a thermodynamic equation of specific Heat was applied to calculate the Specific Heat of solution mathematically in numeric value which was 3214.72476 J or 3.21472 KJ. It was seen that as the base was mixed into acid, the temperature of solution was increased to maximum rapidly showing the exothermic reaction. After reaching to maximum range, the temperature decreased gradually to its minimum range being constant and consistent. The consistent temperature range terminated the reaction. All variations in temperature ranges were recorded very carefully and a table with a graph showing all ups and downs in temperature ranges was drawn on MS Excel Data Sheet.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79106578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The System of Medical Application System Application of the Difference between the Fuzzy Logic and the Neural Networks 模糊逻辑和神经网络在医疗应用系统应用中的区别
Pub Date : 2017-10-25 DOI: 10.4172/2161-0398.1000258
Kadhim Ajeel Obaid
Singled out for this research study the issue of fuzzy logic and use in the medical field to set the values estimated for the data thalassemiapatients, as well as the research involved a study hybridization fuzzy logic with artificial neural networks and the application form hybrid data and note the accuracy of the results between the two systems, which proved to form hybrid superiority large in the accuracy of results compared with the system fuzzy.
本研究专门研究了模糊逻辑的问题,并将其应用于医学领域,对地中海患者的数据进行了数值估计,同时研究了模糊逻辑与人工神经网络的混合,并将其应用于混合数据中,并注意到两种系统之间结果的准确性,证明了与系统模糊相比,形成混合的优势在结果的准确性上较大。
{"title":"The System of Medical Application System Application of the Difference between the Fuzzy Logic and the Neural Networks","authors":"Kadhim Ajeel Obaid","doi":"10.4172/2161-0398.1000258","DOIUrl":"https://doi.org/10.4172/2161-0398.1000258","url":null,"abstract":"Singled out for this research study the issue of fuzzy logic and use in the medical field to set the values estimated for the data thalassemiapatients, as well as the research involved a study hybridization fuzzy logic with artificial neural networks and the application form hybrid data and note the accuracy of the results between the two systems, which proved to form hybrid superiority large in the accuracy of results compared with the system fuzzy.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76384355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Threshold photoelectron and electron-ion coincidence spectroscopies: Past, present and future 阈值光电子和电子-离子重合光谱:过去、现在和未来
Pub Date : 2017-10-20 DOI: 10.4172/2161-0398-C1-025-011
R. Tuckett, T. Baer
{"title":"Threshold photoelectron and electron-ion coincidence spectroscopies: Past, present and future","authors":"R. Tuckett, T. Baer","doi":"10.4172/2161-0398-C1-025-011","DOIUrl":"https://doi.org/10.4172/2161-0398-C1-025-011","url":null,"abstract":"","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86167901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Multidimensional solitons in dispersive complex media: Structure and stability 色散复杂介质中的多维孤子:结构与稳定性
Pub Date : 2017-10-13 DOI: 10.4172/2161-0398-C1-021
V. Belashov
{"title":"Multidimensional solitons in dispersive complex media: Structure and stability","authors":"V. Belashov","doi":"10.4172/2161-0398-C1-021","DOIUrl":"https://doi.org/10.4172/2161-0398-C1-021","url":null,"abstract":"","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76552160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Investigation of Adsorption Process of Hydrogen on Fe-Ti: Theoretical Simulation and Interpretation of Isotherms with Statistical Physics Treatment 氢在Fe-Ti上吸附过程的研究:等温线的理论模拟和统计物理处理解释
Pub Date : 2017-10-01 DOI: 10.4172/2161-0398.1000260
M. Manaa, M. Hachicha, B. Schmaltz, Ben Lamine Abdelmottaleb
Three theoretical expressions for the adsorption isotherms of hydrogen on Fe-Ti at three temperatures 100 K, 80 K and 60 K have been established. Our objective in this modeling is to select the adequate model that presents a high correlation with the experimental curves. The establishment of these new expressions is based on statistical physics formalism. This method has allowed the estimation of physicochemical parameters in the theoretical model. The parameters intervening in the adsorption process have been deduced directly from experimental adsorption isotherms by numerical simulation. We will mainly introduce three main parameters affecting the adsorption process, namely: the density of hydrogen receptor sites Nm, the number of molecules per site n and the pressure at half saturation P1 which characterizes the binding between the hydrogen and receptor sites on Fe-Ti. Then we apply the model to calculate the internal energies in an isothermal transformation, an isobaric transformation and an isosteric transformation.
建立了氢在Fe-Ti上在100k、80k和60k三种温度下吸附等温线的三个理论表达式。我们建模的目的是选择与实验曲线高度相关的适当模型。这些新表达式的建立是基于统计物理的形式主义。这种方法可以估计理论模型中的物理化学参数。通过数值模拟,直接从实验吸附等温线推导出影响吸附过程的参数。我们将主要介绍影响吸附过程的三个主要参数,即:氢受体位点的密度Nm,每个位点的分子数n和表征氢与Fe-Ti受体位点结合的半饱和压力P1。然后应用该模型计算了等温转换、等压转换和等压转换的热力学能。
{"title":"Investigation of Adsorption Process of Hydrogen on Fe-Ti: Theoretical Simulation and Interpretation of Isotherms with Statistical Physics Treatment","authors":"M. Manaa, M. Hachicha, B. Schmaltz, Ben Lamine Abdelmottaleb","doi":"10.4172/2161-0398.1000260","DOIUrl":"https://doi.org/10.4172/2161-0398.1000260","url":null,"abstract":"Three theoretical expressions for the adsorption isotherms of hydrogen on Fe-Ti at three temperatures 100 K, 80 K and 60 K have been established. Our objective in this modeling is to select the adequate model that presents a high correlation with the experimental curves. The establishment of these new expressions is based on statistical physics formalism. This method has allowed the estimation of physicochemical parameters in the theoretical model. The parameters intervening in the adsorption process have been deduced directly from experimental adsorption isotherms by numerical simulation. We will mainly introduce three main parameters affecting the adsorption process, namely: the density of hydrogen receptor sites Nm, the number of molecules per site n and the pressure at half saturation P1 which characterizes the binding between the hydrogen and receptor sites on Fe-Ti. Then we apply the model to calculate the internal energies in an isothermal transformation, an isobaric transformation and an isosteric transformation.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74238141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Chitosan Hydrogels and their Glutaraldehyde-Crosslinked Counterparts as Potential Drug Release and Tissue Engineering Systems - Synthesis, Characterization, Swelling Kinetics and Mechanism 壳聚糖水凝胶及其戊二醛交联对应物作为潜在药物释放和组织工程系统的合成、表征、溶胀动力学和机理
Pub Date : 2017-09-30 DOI: 10.4172/2161-0398.1000256
O. Akakuru, B. Isiuku
Snail shells had been utilized to prepare chitosan and hydrogels of the chitosan were also prepared and crosslinked with varying amounts of glutaraldehyde to achieve different crosslink densities between 0.75 and 1.50. The materials were characterized in terms of the dependence of their swellabilities on time and pH. FTIR analysis was also carried out on the hydrogels and the results obtained show a band at 3451 cm-1, attributed to O-H stretching of the chitosan. The crosslinked hydrogels also showed an N-H bending vibration at 1635 cm-1 which has a reduced intensity and has moved to a lower wavenumber when compared to the N-H bending vibration of the uncrosslinked chitosan hydrogels at 1652 cm-1. The swelling studies showed that the extent of swelling of the hydrogels was dependent on the crosslink density (CD), increasing as CD increased. Uncrosslinked chitosan hydrogel had maximum swelling of 162.71% while that for the crosslinked chitosan hydrogels with CD of 0.75, 1.00 and 1.50 were 119.87%, 93.21% and 87.65% respectively. In all cases, their crosslinked counterparts had decreased swellabilities suggesting that, the crosslinked chitosan hydrogels can be used for a more controlled delivery of drugs and as efficient materials for tissue engineering. The chitosan hydrogels showed maximum percent swellability in highly acidic medium (pH2) equally suggesting the potential of these hydrogels as drug release systems in this medium. The swelling of the chitosan hydrogels followed second-order kinetics and their swelling diffusion exponents ranged from 0.142 to 0.155, indicative of a Less Fickian diffusion or transport mode.
以蜗牛壳为原料制备壳聚糖,制备壳聚糖水凝胶,并与不同量的戊二醛交联,交联密度在0.75 ~ 1.50之间。材料的溶胀性随时间和ph值的变化而变化。FTIR分析结果显示,在3451 cm-1处有一个条带,这是壳聚糖的O-H拉伸引起的。与未交联壳聚糖水凝胶在1652 cm-1处的N-H弯曲振动相比,交联壳聚糖水凝胶在1635 cm-1处的N-H弯曲振动强度降低,且波数更低。溶胀研究表明,水凝胶的溶胀程度与交联密度(CD)有关,随交联密度的增大而增大。未交联壳聚糖水凝胶最大溶胀率为162.71%,而CD为0.75、1.00和1.50的交联壳聚糖水凝胶最大溶胀率分别为119.87%、93.21%和87.65%。在所有情况下,它们的交联对应物的溶胀性都降低了,这表明,交联壳聚糖水凝胶可以用于更可控的药物输送,并作为组织工程的有效材料。壳聚糖水凝胶在高酸性介质(pH2)中具有最大的溶胀性,这表明壳聚糖水凝胶在高酸性介质中具有作为药物释放系统的潜力。壳聚糖水凝胶的溶胀服从二级动力学,溶胀扩散指数在0.142 ~ 0.155之间,属于Less Fickian扩散或输运模式。
{"title":"Chitosan Hydrogels and their Glutaraldehyde-Crosslinked Counterparts as Potential Drug Release and Tissue Engineering Systems - Synthesis, Characterization, Swelling Kinetics and Mechanism","authors":"O. Akakuru, B. Isiuku","doi":"10.4172/2161-0398.1000256","DOIUrl":"https://doi.org/10.4172/2161-0398.1000256","url":null,"abstract":"Snail shells had been utilized to prepare chitosan and hydrogels of the chitosan were also prepared and crosslinked with varying amounts of glutaraldehyde to achieve different crosslink densities between 0.75 and 1.50. The materials were characterized in terms of the dependence of their swellabilities on time and pH. FTIR analysis was also carried out on the hydrogels and the results obtained show a band at 3451 cm-1, attributed to O-H stretching of the chitosan. The crosslinked hydrogels also showed an N-H bending vibration at 1635 cm-1 which has a reduced intensity and has moved to a lower wavenumber when compared to the N-H bending vibration of the uncrosslinked chitosan hydrogels at 1652 cm-1. The swelling studies showed that the extent of swelling of the hydrogels was dependent on the crosslink density (CD), increasing as CD increased. Uncrosslinked chitosan hydrogel had maximum swelling of 162.71% while that for the crosslinked chitosan hydrogels with CD of 0.75, 1.00 and 1.50 were 119.87%, 93.21% and 87.65% respectively. In all cases, their crosslinked counterparts had decreased swellabilities suggesting that, the crosslinked chitosan hydrogels can be used for a more controlled delivery of drugs and as efficient materials for tissue engineering. The chitosan hydrogels showed maximum percent swellability in highly acidic medium (pH2) equally suggesting the potential of these hydrogels as drug release systems in this medium. The swelling of the chitosan hydrogels followed second-order kinetics and their swelling diffusion exponents ranged from 0.142 to 0.155, indicative of a Less Fickian diffusion or transport mode.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91320727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 63
Radioactivity: An Introduction to Mysterious Science 放射性:神秘科学导论
Pub Date : 2017-09-08 DOI: 10.4172/2161-0398.1000254
N. Khan
Materials that undergo decay process to attain a stable configuration followed by the emission of particles such as alpha, beta and gamma are termed as radioactive elements. Radioactivity is measured in Curie (Ci) and Becquerel (Bq) SI units. Though radioactive elements are abundant on Earth and constantly decays to produce stable nuclei but such nuclear decay process may pose serious health threats to living beings. Therefore, must be regulated when working in vitro. Biosafety levels should be strictly observed when engaged in radioactive experiments to minimize contamination exposure.
经过衰变过程以获得稳定构型的物质,随后会发射出诸如α、β和γ等粒子,这些物质被称为放射性元素。放射性的测量单位是居里(Ci)和贝克勒尔(Bq) SI。虽然地球上放射性元素丰富,并不断衰变产生稳定的原子核,但这种核衰变过程可能对生物的健康造成严重威胁。因此,在体外工作时必须加以调节。在进行放射性实验时应严格遵守生物安全水平,以尽量减少污染暴露。
{"title":"Radioactivity: An Introduction to Mysterious Science","authors":"N. Khan","doi":"10.4172/2161-0398.1000254","DOIUrl":"https://doi.org/10.4172/2161-0398.1000254","url":null,"abstract":"Materials that undergo decay process to attain a stable configuration followed by the emission of particles such as alpha, beta and gamma are termed as radioactive elements. Radioactivity is measured in Curie (Ci) and Becquerel (Bq) SI units. Though radioactive elements are abundant on Earth and constantly decays to produce stable nuclei but such nuclear decay process may pose serious health threats to living beings. Therefore, must be regulated when working in vitro. Biosafety levels should be strictly observed when engaged in radioactive experiments to minimize contamination exposure.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86345789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Kinetics and Solvent Effect in Hydrolysis of Ethyl Cinnamate in Water- Methanol Mixture 肉桂酸乙酯在水-甲醇混合物中水解动力学及溶剂效应
Pub Date : 2017-08-14 DOI: 10.4172/2161-0398.1000252
S. Ak
The solvent effect of ethanol on the alkali catalyzed solvolysis reaction was studied by carring out of the hydrolysis of ester namely ethyl cinnamate in water-methanol media of varying composition consisting of 30 to 70% of methanol (v/v) at different Temperature ranging from 20°C to 70°C. The Specific rate constant values of the reaction were found to depleted with increasing concentration of methanol in reaction media. Enhancement in ΔG* with simultaneous depletion in ΔH* and ΔS* of the reaction, it has been concluded that reaction is enthalpy stimulating and entropy inhibiting and specific salvation take place in water- methanol media. From the evaluated value of Iso kinetic temperature, which is less than 300 indicates that this reaction in water-methanol media obey Barclay-Butler rule and there is weak but considerable solvent –solute interaction taking place in reaction media.
以肉桂酸乙酯为溶剂,在甲醇含量为30 ~ 70% (v/v)的水-甲醇介质中,在20 ~ 70℃的温度范围内进行水解,研究了乙醇对碱催化溶剂解反应的溶剂效应。随着反应介质中甲醇浓度的增加,反应的比速率常数值逐渐减小。在ΔG*中增强,同时在ΔH*和ΔS*中减弱,可以得出在水-甲醇介质中发生焓激发和熵抑制反应和特异性拯救的结论。从等动力学温度的评定值来看,小于300表明该反应在水-甲醇介质中服从Barclay-Butler规则,反应介质中发生了微弱但相当大的溶剂-溶质相互作用。
{"title":"Kinetics and Solvent Effect in Hydrolysis of Ethyl Cinnamate in Water- Methanol Mixture","authors":"S. Ak","doi":"10.4172/2161-0398.1000252","DOIUrl":"https://doi.org/10.4172/2161-0398.1000252","url":null,"abstract":"The solvent effect of ethanol on the alkali catalyzed solvolysis reaction was studied by carring out of the hydrolysis of ester namely ethyl cinnamate in water-methanol media of varying composition consisting of 30 to 70% of methanol (v/v) at different Temperature ranging from 20°C to 70°C. The Specific rate constant values of the reaction were found to depleted with increasing concentration of methanol in reaction media. Enhancement in ΔG* with simultaneous depletion in ΔH* and ΔS* of the reaction, it has been concluded that reaction is enthalpy stimulating and entropy inhibiting and specific salvation take place in water- methanol media. From the evaluated value of Iso kinetic temperature, which is less than 300 indicates that this reaction in water-methanol media obey Barclay-Butler rule and there is weak but considerable solvent –solute interaction taking place in reaction media.","PeriodicalId":94103,"journal":{"name":"Journal of physical chemistry & biophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90326187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
期刊
Journal of physical chemistry & biophysics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1