Physical–chemical properties

物理化学性质
  • 文章类型: Journal Article
    在制备固定假体(包括单个桥和冠)期间,重要的是选择具有最佳特征和性能的材料以预测成功的临床治疗。这项研究的目的是确定化学和结构特征是否会导致抗断裂性增加,我们用了四种双丙烯酸树脂Luxatemp,Protemp,Structur和Telio.通过弯曲测试在十条中进行三点弯曲,并与Anova测试进行比较。此外,通过扫描电子显微镜分析了双丙烯酸树脂,通过衰减全反射红外光谱对分子的微观结构和形貌进行分析。在Luxatemp和Structur中发现了更高的弯曲强度,本研究组间无显著差异.关于Protemp和Telio,与Luxatemp和Structur相比,这些研究组显示出较低的弯曲强度。这些结果证实了SEM和ATR分析,因为Luxatemp样品在表面上显示出规则尺寸的颗粒,并在化学上呈现长交联聚合物链。与其它基团相比,作为与OH基团相互作用的填料颗粒的CO3、SiO2和N-H基团的存在导致更高的弯曲强度。
    During the preparation of fixed prosthesis (including individual bridges and crowns) it is important to select the materials that have the best features and properties to predict a successful clinical treatment. The objective of this study was to determine if the chemical and structural characteristics could cause to increase the fracture resistance, we used four bis-acryl resins Luxatemp, Protemp, Structur and Telio. Three-points bending by Flexural test were performed in ten bars and they were carried out to compare with Anova test. In addition, the bis-acryl resins were analyzed by scanning electron microscopy, to analyze microstructure and morphology and the molecular structure were performed by Infrared Spectroscopy through Attenuated Total Reflectance. A higher flexural strength was found in Luxatemp and Structur with, no significant differences between this study groups. Regarding Protemp and Telio, these study groups showed a lower flexural strength when were compared with Luxatemp and Structur. These results corroborate SEM and ATR analysis because Luxatemp sample showed a regular size particle on the surface and chemically presents a long cross-linkage polymer chain. The presence of CO3, SiO2 and N-H groups as a fillers particle interacting with OH groups cause a higher flexural strength compared with another groups.
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  • 文章类型: Journal Article
    在葡萄种植中,不正确的水调节将导致大量的水浪费,这反过来会改变土壤结构并破坏土壤养分循环过程。本研究旨在研究不同水分调节处理[通过设置适度的水分胁迫(W1),轻度水分胁迫(W2),和充足的水分可利用性(CK)]在生长季节对温室葡萄的土壤理化性质和酶活性的影响。结果表明,W2处理对溶解有机碳(DOC)的积累有负面影响,硝酸盐氮(NO3-N),和有效磷(AP)。在整个生育期,W1和W2处理降低了土壤微生物生物量碳(MBC)和微生物生物量氮(MBN)含量,MBC更容易受到水分压力的影响。在生长期,脲酶的发展趋势,过氧化氢酶,不同土壤深度的蔗糖酶活性等级为10-20cm>0-10cm>20-40cm。W1和W2处理均抑制了0-10厘米土壤中的脲酶活性,而W1处理下各个土壤层的转化酶活性差异很大。W1处理还降低了葡萄生长季节20-40cm土层中过氧化氢酶的活性。这些发现表明W2处理可以保持水分并增强温室葡萄土壤的微生物生态。因此,W2处理是当地温室葡萄栽培最有效的水分调节措施。
    In grape cultivation, incorrect water regulation will lead to significant water wastage, which in turn will change soil structure and disrupt soil nutrient cycling processes. This study aimed to investigate the effects of different water regulation treatments [by setting moderate water stress (W1), mild water stress (W2), and adequate water availability (CK)] on soil physical-chemical properties and enzyme activity in greenhouse grape during the growing season. The result showed that the W2 treatment had a negative impact on the build-up of dissolved organic carbon (DOC), nitrate nitrogen (NO3-N), and available phosphorus (AP). Throughout the reproductive period, the W1 and W2 treatments decreased the soil\'s microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents, and MBC was more vulnerable to water stress. During the growth period, the trends of urease, catalase, and sucrase activities in different soil depth were ranked as 10-20 cm > 0-10 cm > 20-40 cm. The urease activity in 0-10 cm soil was suppressed by both W1 and W2 treatments, while the invertase activity in various soil layers under W1 treatment differed substantially. The W1 treatment also reduced the catalase activity in the 20-40 cm soil layer in the grape growth season. These findings suggested that W2 treatment can conserve water and enhance microbial ecology of greenhouse grape soils. Therefore, W2 treatment was the most effective water regulation measure for local greenhouse grape cultivation.
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  • 文章类型: Journal Article
    这项研究的目的是调查痕量金属(As,Cr,Cu,Ni,Pb,Fe,和Zn)以及与Ebolowa市政湖(EML)盆地相关的健康和致癌风险。为此,从EML及其两个支流中收集了21个水样,Mfoumou和Bengo\'o,并使用MACHEREY-NAGEL光度计通过Quantofix方法(纳米颜色和可见颜色ECO)进行分析。使用多变量统计对数据进行处理。结果表明,所有的理化参数(pH,EC,和TDS),除了TDS,符合世卫组织的规定。研究的三个地点的痕量金属分布如下:Zn(80-400±1.58µg/L)>Cu(50-150±9.38µg/L)>Fe(10-40±0.71µg/L)>Pb(1-20±3.02µg/L)>As(1-9±0.44µg/L)>Ni(1-9±1.48µg/L)。然而,在EML和Mfoumou河中观察到最高值,注意到铅污染。统计分析表明,人为输入增加了Cr的存在,Cu,Pb,和Zn。所有地点的痕量金属污染指数值均低于15,说明低水平的污染。本戈流的痕量金属评估指数值是纯的(平均值=0.6),在Mfoumou流中受到轻微影响(平均值=2.0),在EML中受到中度影响(平均值=2.2)。毒性负荷指数值表明所研究的水是有毒的。非致癌(HI)和致癌(CR)健康风险指数值表明与LME和Mfoumou水道中的口服摄入有关的风险。后者似乎是输入EML的外来污染物的主要来源。
    The aim of this study was to investigate the status of trace metals (As, Cr, Cu, Ni, Pb, Fe, and Zn) and health and carcinogenic risk associated then in the Ebolowa Municipal Lake (EML) basin. To this end, 21 water samples were collected from the EML and its two tributaries, Mfoumou and Bengo\'o, and analyzed by Quantofix method (nanocolors and visiocolor ECO) by using the MACHEREY-NAGEL photometer. The data were processed using multivariate statistics. The results showed that all the physicochemical parameters (pH, EC, and TDS), with the exception of TDS, comply with were within WHO limits. The distribution of trace metals at the three sites investigated was as follows: Zn (80-400 ± 1.58 µg/L) > Cu (50-150 ± 9.38 µg/L) > Fe (10-40 ± 0.71 µg/L) > Pb (1-20 ± 3.02 µg/L) > As (1-9 ± 0.44 µg/L) > Ni (1-9 ± 1.48 µg/L). However, the highest values were observed in the EML and the Mfoumou River, where Pb pollution was noted. Statistical analysis showed that anthropogenic inputs increase the presence of Cr, Cu, Pb, and Zn. Trace Metal Pollution Index values were below 15 at all sites, illustrating low levels of pollution. The trace metal evaluation index values for the Bengo\'o stream are pure (mean = 0.6), slightly affected in the Mfoumou stream (mean = 2.0), and moderately affected in the EML (mean = 2.2). The toxicity load index values illustrate that the waters studied are toxic. The non-carcinogenic (HI) and carcinogenic (CR) health risk index values suggest a risk linked to oral ingestion in the LME and Mfoumou watercourses. The latter appears to be the main source of allochthonous pollutant input to the EML.
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  • 文章类型: Journal Article
    在所谓的绿色分析化学领域,寻找新的分析方法是一个潜在的现实,旨在将分析需求与环境问题相关联。在使用的方法中,有可能强调绿色溶剂作为危险和常规有机溶剂的替代品,作为最突出的替代品。在过去的几年里,大量的研究集中在深共晶溶剂(DES)的使用已经增长作为替代这些问题。因此,这项工作旨在研究七种不同DES的主要物理化学和生态毒性。结果表明,DESs的评估性质受其前体的化学结构的影响,这可能会调节DES的粘度,肤浅的张力,以及对植物组织和微生物细胞的拮抗作用。这里指出的结论从绿色分析的角度引入了关于DES有意识使用的新视角。
    The search for new analytical methods is a latent reality in the so-called green analytical chemistry area, which aims at correlating analytical demands to environmental issues. Among the approaches used, it is possible to highlight green solvents as substitutes to the dangerous and conventional organic solvents as the most prominent alternative for this purpose. In the last few years, the amount of research focused on the usage of deep eutectic solvents (DESs) has been growing as an alternative to these issues. Thus, this work aimed to investigate the main physical-chemical and ecotoxical properties of seven different DESs. The results showed that DESs\' evaluated properties are influenced by the chemical structure of their precursors, which may regulate DESs\' viscosity, superficial tension, and antagonistic action against vegetable tissues and microbial cells. The constatations pointed here introduce a new perspective about the conscious usage of DESs on a green analytical point of view.
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  • 文章类型: Journal Article
    乳酸菌产生的胞外多糖(EPS)具有多种生物活性和潜在的科学探索和商业开发吸引力。产生EPS的细菌菌株,RSG7以前是从pepino中分离的,并被鉴定为中肠明串珠菌。基于高效尺寸排阻色谱的分析,高效离子色谱法,傅里叶变换红外光谱,核磁共振波谱,甲基化,RSG7EPS被鉴定为分子量为5.47×106Da的葡聚糖,由α-(1→6)糖苷键作为主链和α-(1→2)组成,α-(1→3),α-(1→4),和α-(1→6)糖苷键作为侧链。扫描电子显微镜观察到RSG7葡聚糖的蜂窝状多孔结构,根据原子力显微镜分析,这种右旋糖酐形成了不规则的丘状团块。物理化学研究表明,RSG7葡聚糖在高浓度下具有优异的粘度,低温,和高pH值;测试植物油的乳化能力优于碳氢化合物;在活性炭悬浮固体中具有最大的絮凝活性(10.74±0.23)和絮凝率(93.46±0.07%)。此外,右旋糖酐可以凝结补充蔗糖的牛奶,并暗示了潜在的体外益生菌。一起,这些结果共同描述了一种有价值的右旋糖酐,具有独特的特性,可用于食品应用。
    Exopolysaccharides (EPSs) produced by lactic acid bacteria possess various bioactivities and potential attractions for scientific exploration and commercial development. An EPS-producing bacterial strain, RSG7, was previously isolated from the pepino and identified as Leuconostoc mesenteroides. Based on the analyses of high-performance size exclusion chromatography, high-performance ion chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and methylation, the RSG7 EPS was identified as a dextran with a molecular weight of 5.47 × 106 Da and consisted of α-(1→6) glycosidic linkages as backbone and α-(1→2), α-(1→3), α-(1→4), and α-(1→6) glycosidic linkages as side chains. Scanning electron microscopy observed a honeycomb-like porous structure of RSG7 dextran, and this dextran formed aggregations with irregular hill-shaped lumps according to atomic force microscopy analysis. Physical-chemical investigations suggested that RSG7 dextran possessed excellent viscosity at high concentration, low temperature, and high pH; showed a superior emulsifying capacity of tested vegetable oils than that of hydrocarbons; and owned the maximal flocculating activity (10.74 ± 0.23) and flocculating rate (93.46 ± 0.07%) in the suspended solid of activated carbon. In addition, the dextran could coagulate sucrose-supplemented milk and implied potential probiotics in vitro. Together, these results collectively describe a valuable dextran with unique characteristics for exploitation in food applications.
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  • 文章类型: Journal Article
    Formic acid pretreatment is a promising approach for fractionating biomass, and it has the advantages of efficient recycling and removal of hemicellulose and lignin. Biomass is one of the most plentiful resources on earth, yet its chemical structure differs significantly between woody and herbaceous biomass. The influence of formic acid pretreatment on the fractionation of woody and herbaceous biomasses, as well as changes in physical-chemical properties, was investigated in this study. The results indicated that formic acid is universal in the biorefinery of different biomass, however, herbaceous biomass had greater xylan and lignin removal than woody biomass (especially softwood). Formic acid pretreatment not only considerably improved the enzymatic efficiency of herbaceous biomass, but also had a good effect on the enzymatic efficiency of poplar. This study also found that the correlation between residual xylan content and enzymatic efficiency after pretreatment was much higher than that of lignin content.
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  • 文章类型: Journal Article
    氧化铁纳米颗粒是用于医学(诊断和治疗)和生物相关应用的最有前途的磁响应纳米颗粒系统的基本组成部分。具有高磁矩和明确尺寸的多芯氧化铁纳米颗粒,形状,和功能涂层旨在满足各种生物医学应用的特定要求,如造影剂,加热介质,药物靶向,或磁性生物分离。这篇综述文章总结了制造多核磁性纳米颗粒(MNP)系统的最新成果,强调了合成程序,以铁磁流体(具有单核MNPs)为主要材料,在各种组装方法中获得多核磁性粒子。合成和官能化之后将是先进的物理化学结果,结构,和多核粒子的磁性表征,以及单核和多核粒度分布,形态学,内部结构,团聚体形成过程,以及恒定和可变场的磁特性。该综述提供了对纳米医学和生物技术设想的多芯磁性复合材料的受控合成以及先进的结构和磁性表征的全面见解。
    Iron oxide nanoparticles are the basic components of the most promising magnetoresponsive nanoparticle systems for medical (diagnosis and therapy) and bio-related applications. Multi-core iron oxide nanoparticles with a high magnetic moment and well-defined size, shape, and functional coating are designed to fulfill the specific requirements of various biomedical applications, such as contrast agents, heating mediators, drug targeting, or magnetic bioseparation. This review article summarizes recent results in manufacturing multi-core magnetic nanoparticle (MNP) systems emphasizing the synthesis procedures, starting from ferrofluids (with single-core MNPs) as primary materials in various assembly methods to obtain multi-core magnetic particles. The synthesis and functionalization will be followed by the results of advanced physicochemical, structural, and magnetic characterization of multi-core particles, as well as single- and multi-core particle size distribution, morphology, internal structure, agglomerate formation processes, and constant and variable field magnetic properties. The review provides a comprehensive insight into the controlled synthesis and advanced structural and magnetic characterization of multi-core magnetic composites envisaged for nanomedicine and biotechnology.
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  • 文章类型: Journal Article
    This paper presents phosphorus content, the activity of enzymes, and relationships between chemical properties in former sulphur mine soil ecosystems. Soil sampled 16 years after the completion of open-pit mining works at Machów, and 7 years after sulphur mining by the \"melting\" method was abandoned in the Jeziórko mine. In these soil samples were determined content of total (TP), mineral (MP), organic (OP), available (AP) phosphorus, the activity of catalase (CAT), dehydrogenases (DHA), alkaline (AlP) and acid (AcP) phosphatase, and metabolic metabolic quotient (qCO2). Total phosphorus content in samples from the Machów mine ranged from 0.297 to 0.392 g kg-1. In the soil from the vicinity Jeziórko, TP content was in the range 0.329-0.460 g kg-1. The content of AP in soil from the vicinity of Machów range from 10.77 to 43.44 mg kg-1, and near the Jeziórko mine from 5.73 to 18.03 mg kg-1. Availability factor (AF) for phosphorus was calculated, which was higher in soil under the impact of the Machów mine compared to the soil near the of Jeziórko mine. The activity of AlP in soil around the Jeziórko mine was lower than in soils sampled near the Machów mine. Enzymatic activity and total carbon content were used to calculate the biochemical activity index (BA12), which was higher in soils under the impact of the Machów mine. The value of metabolic quotient (qCO2) was low in the upper layers of the clarifier (Machów) and also 10 and 40 m from the borehole Jeziórko. The highest value of this parameter was observed in soil from the post-process waste dump at Machów (3.6 μgCO2 [μgC mic]-1 h-1). A long-term human impact significantly affected the soil phosphorus under study and the physico-chemical properties, which led to a change in the enzymatic activity of soil.
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  • 文章类型: Journal Article
    UNASSIGNED: This review shows the history of inventions of devices, hygiene products, and methods of dissolution and removal of pus, sulfur plugs, blood crusts, and plaque.
    UNASSIGNED: The search for inventions was carried out in the databases, such as Google Patent, Google Scholar, Scopus, and PubMed. The key words used in this search were as follows: toothbrushes, toothpicks, toothpastes, plaque, cleaning products for teeth and dentures, teeth whiteners and dentures, bleach bruises and blood stains, pus, sulfur plugs, and pus solvents. A total of 24 inventions were evaluated for review.
    UNASSIGNED: In recent years, hygiene products that quickly dissolve and bleach pus, sulfur plugs, blood stains, and plaque because of alkaline saponification of protein-lipid complexes and cold boiling inside the biological masses have been invented. Such an action has a heated above 37°C supersaturated sodium bicarbonate solutions containing hydrogen peroxide in moderate concentrations and gaseous oxygen under excessive pressure. Cold boiling inside the dense biological masses occurs under the action of catalase and/or due to the normalization of internal pressure in the solution.
    UNASSIGNED: Alkalinity, hyperthermia, and hyperoxygenation of solutions with high internal pressure optimize whitening of teeth and dentures because of alkaline saponification and cold boiling.
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  • 文章类型: Journal Article
    Economic value is no longer adequate by itself as a proxy for the value-added benefits (VAB) assumed to be generated by emerging technologies such as engineered nanomaterials (ENMs). This study was conducted to explore the potential to establish an integrated sociotechnical framework with the end goal to assess whether or not ENMs and nano-enabled products contribute VAB. Based on the research in this study, it is suggested that all stakeholders in the larger society-environment-economy (SEE) system should develop an understanding of the multiple interrelationships within and between the diverse constituents along the particle lifecycle trajectory to capture their influence on the system benefit and risk outcomes. Furthermore, the sociotechnical framework establishes an additional three-step process: (1) at the pre-design stage, the test of VAB should be assessed using an expert panel representing the different segments of SEE, the social principles of design are detailed and customized to the needs of ENMs and nano-enabled products, and an economic appraisal is conducted to justify the VAB on material grounds; (2) at the design stage, the technical principles should be examined and detailed to ensure the compatibility of stakeholder needs; and (3) an iterative adaptive cycle should be conducted to re-examine the sociotechnical principles on a periodic basis. Within this context, ENMs are considered sustainable when (a) the conditions of VAB and minimal risk elements are satisfied in a sequential order, with VAB demonstrated at the pre-design stage, then at the design stage ENMs posing no harm greater than minimal levels to the SEE constituents; and (b) ENMs and nano-enabled products are bounded by a finite time limit. In addition, to reach the conditions of sustainability, the role of all SEE stakeholders should be broadened (e.g., regulatory agencies should transform their roles from not only the control of risks of negative implications, but also the establishment of positive implications as well).
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