Density

密度
  • 文章类型: Journal Article
    该研究是在不同浓度和温度下,在乙酸乙酯和丙酮水溶液中,热物理性质对依氟鸟氨酸药物溶质-溶剂相互作用的影响。本研究的目的是加强对依氟鸟氨酸在不同溶剂中的行为的理解,这对于其在药物应用中的有效使用至关重要。密度,摩尔体积,测粘度,在298.15K-318.15K的温度范围内,测量了依氟鸟氨酸药物溶液(0.025、0.05、0.075、0.1和0.125mol/kg)在丙酮和25%(v/v)乙酸乙酯水溶液中的电导率特性。基于确定的密度参数,评估以下参数:粘度(η),等效摩尔电导,极限表观摩尔体积(V0φ),表观转移摩尔体积(V0φtr),和表观摩尔体积(Vφ)。使用Masson经验关系和粘度对Jones-Dole(JD)方程来评估部分摩尔体积(Vφ),实验坡度(SV),粘度,和密度数据。使用温度和浓度来确定每个参数。对于每组稀释,在两种研究溶剂中进行了电导研究。分析收集的数据以评估离子-溶剂相互作用。Walden产品Δomη的正温度系数值表明,药物依氟鸟氨酸在丙酮和乙酰乙酸水溶液系统中起结构改性剂的作用。确定了极性溶剂丙酮和乙酸乙酯的结构形成和破坏特性。
    The study was conducted on the impact of thermophysical properties on eflornithine drug solute-solvent interactions in aqueous ethyl acetate and acetone at different concentrations and temperatures. The aim of this study is to enhance the understanding of eflornithine\'s behavior in different solvents, which is crucial for its effective use in pharmaceutical applications. The density, molar volume, viscometric, and conductometric characteristics of the eflornithine drug solutions (0.025, 0.05, 0.075, 0.1, and 0.125 mol/kg) in acetone and 25% (v/v) aqueous ethyl acetate were measured within a temperature range of 298.15 K-318.15 K. Based on the determined density parameters, the following parameters were assessed: viscosity (η), equivalent molar conductance, limiting apparent molar volume (V0φ), apparent molar volume of transfer (V0φtr), and apparent molar volume (Vφ). The Masson empirical relationship and the viscosity-to-Jones-Dole (JD) equation were used to evaluate the partial molar volume (Vφ), experimental slope (SV), viscosity, and density data. Temperature and concentration were used to determine each parameter. For each set of dilutions, conductometric studies were conducted in both study solvents. The gathered data was analyzed in order to evaluate the ion-solvent interactions. The Walden product Λomηo\'s positive temperature coefficient values indicate that the drug eflornithine functions as a structural modifier in acetone and aqueous acetyl acetate systems. The structure-making and breaking characteristics of the polar solvents acetone and ethyl acetate were identified.
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  • 文章类型: Journal Article
    少年激素(JH),和蜕皮激素一起,调节蜕皮,变态,增长,和节肢动物的繁殖。其类似物用作杀虫剂对非目标物种的影响令人担忧。由于JH和JH类似物(JHAs)在水蚤中诱导雄性后代,通常通过孤雌生殖繁殖,以雄性子代比率为终点的短期JH活性筛选试验(JHASA)已被开发为JHA的检测方法.然而,雄性后代的产生也是由环境压力如温度引起的,短日长度,人满为患,和食物限制。因此,在测试过程中,必须防止非化学应激诱导雄性后代,以准确检测具有潜在JH活性的化学物质。因此,我们研究了温度(低和高)的影响,硬度,高密度,低进料,以及利用JHASA进行男性生产的日长。在JHASA中,雄性后代没有受到任何压力的强烈诱导,尽管在高密度(≥70daphnid/L)和持续黑暗的预培养中观察到4-12%的男性比率。与国家环境研究所(NIES)的菌株相比,克隆A菌株对高密度和日长相对更敏感。建议选择在非化学胁迫下很少产生雄性的菌株,并找到适合不诱导雄性后代的每个菌株的培养条件,以控制和防止JHASA期间的雄性后代诱导。
    Juvenile hormone (JH), together with ecdysone, regulates molting, metamorphosis, growth, and reproduction in arthropods. The effects of its analogs used as insecticides on nontarget species are of concern. Since JH and JH analogs (JHAs) induce male offspring in daphnids, which generally reproduce by parthenogenesis, short-term JH activity screening assay (JHASA) using the male offspring ratio as an endpoint has been developed as a detection method for JHA. However, the production of male offspring is also induced by environmental stresses such as temperature, short-day length, overcrowding, and food limitation. Thus, it is vital to prevent non-chemical stresses from inducing male offspring during the test to detect chemicals with potential JH activity accurately. Therefore, we investigated the effects of temperature (low and high), hardness, high density with low feeding, and day length on male production utilizing JHASA. Male offspring were not strongly induced by any stresses in JHASA, although the male ratios of 4-12% were observed in the preculture under high density (≥70 daphnid/L) and constant darkness. The Clone A strain was relatively more sensitive to high density and day length compared with the strain from National Institute for Environmental Studies (NIES). The selection of strains that rarely produce males under non-chemical stresses and finding the culturing conditions for each strain appropriate for not-inducing male offspring are recommended to control and prevent male offspring induction during JHASA.
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  • 文章类型: Journal Article
    我们旨在评估接受输尿管软镜治疗(fURS)治疗肾结石的患者的CT扫描中内窥镜乳头异常(PA)与高肾乳头Hounsfield密度(PHD)之间的相关性。我们回顾性评估了2016年5月至2020年10月期间接受fURS治疗肾结石的患者。PHD是由放射科医师在术前CT扫描中测量的,该放射科医师对乳头的术中情况视而不见。检查了fURS中描述的高PHD(≥43HU)和PA之间的相关性,石头成分,代谢异常,...在159例连续病例中,131例符合术前CT扫描分析条件。中位年龄为55岁(IQR43-67),中位PHD为40岁(IQR36-45)。80例患者(61%)PHD<43,51例患者(39%)PHD≥43。在单变量和多变量分析中,只有年轻的年龄(p值=0.017)和利尿不足(p值=0.008)与高PHD相关.与内窥镜检查期间描述的PA没有发现显著相关性,包括兰德尔斑块的强度。在这项研究中,高PHD似乎只是利尿不足的征兆,与潜在PA无显著相关性。
    We aimed to evaluate the correlation between endoscopic papillary abnormalities (PA) and high renal papilla Hounsfield density (PHD) on CT scan in patients who underwent flexible ureteroscopic treatment (fURS) for renal stones. We retrospectively assessed patients from a prospectively collected database who were treated with fURS for renal stones between May 2016 and October 2020. PHD was measured on preoperative CT-scan by a radiologist blinded from the intraoperative aspect of the papillae. Correlation was examined between high PHD (≥ 43 HU) and PA described in fURS, stone composition, metabolic abnormalities, … Out of 159 consecutive cases, 131 were eligible for analysis with available preoperative CT-scan. Median age was 55 years (IQR 43-67) and median PHD was 40 (IQR 36-45). Eighty patients (61%) had PHD < 43, and 51 patients (39%) had PHD ≥ 43. In univariate and multivariate analysis, only young age (p-value = 0.017) and insufficient diuresis (p-value = 0.008) were correlated with high PHD. No significant correlation was found with PA described during endoscopy, including the intensity of Randall\'s plaques. In this study, high PHD appears to be only a sign of insufficient diuresis, with no significant correlation with potential PA.
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  • 文章类型: Journal Article
    COVID-19大流行强调了创造和研究具有改善亲脂性和抗菌特性的新物质的必要性,如离子液体(IL),具有易于调节的物理化学性质。大多数IL具有很强的抗菌作用,但含有咪唑鎓阳离子的IL甚至比阳性对照更有效。因此,在这项研究中,三种具有1-丁基-3-甲基咪唑阳离子和各种羧酸根阴离子的离子液体(苯乙酸,苯甲酸盐,和4-甲氧基苯基乙酸酯)的合成和充分表征。根据实验密度讨论了阳离子和阴离子之间的相互作用,粘度,和导电性。从测量的电导率和粘度,构造了Walden图,并讨论了所研究IL的离子性。通过应用层次聚类分析和计算机计算性质,分析了所研究的IL及其理化性质之间的异同。在两种细菌(E.大肠杆菌和铜绿假单胞菌)和三种真菌(P.疣,A.黄花,和寄生虫)菌株,发现与单个成分相比,它们显示出改善的抗菌活性。
    The COVID-19 pandemic highlighted the need to create and study new substances with improved lipophilicity and antimicrobial properties, such as ionic liquids (ILs), with easily tunable physicochemical properties. Most ILs possess strong antibacterial effects, but ILs containing the imidazolium cation are even more effective than the positive control. Thus, in this study, three ionic liquids with 1-butyl-3-methylimidazolium cation and various carboxylate anions (phenylacetate, benzoate, and 4-methoxyphenylacetate) were synthesized and fully characterized. The interactions between the cations and anions were discussed based on the experimental density, viscosity, and electrical conductivity. From the measured electrical conductivity and viscosity, the Walden plot is constructed and ionicity of the studied ILs is discussed. The similarities and dissimilarities among the studied ILs and their physicochemical properties are analyzed by applying the hierarchical cluster analysis and in silico calculated properties. The antimicrobial activity of the studied ionic liquids is tested on two bacterial (E. coli and P. aeruginosa) and three fungi (P. verrucosum, A. flavus, and A. parasiticus) strains, finding that they showed improved antimicrobial activity compared to the individual components.
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  • 文章类型: Journal Article
    在混凝土建成结构的情况下,静态割线弹性模量(Ec,s)通常是根据通过超声脉冲速度法测得的其动态值(Ed)来估算的,而不是在钻取的岩心上进行的直接测试。同时,用于估计Ec的主要方程,我们经常忽略混凝土水分的影响。这项研究旨在阐明两个抗压强度不同(51.6和71.4MPa)的正常重量结构混凝土的水分影响。仅对较弱的混凝土,水分含量的影响才更加明显。根据动态模量测量。在其他情况下,与文献报道和预期相反,这种影响被证明是微不足道的。这些观察结果可以通过两个因素来解释:测试混凝土的相对致密和均匀的结构以及Ec的灵敏度降低。与使用超声波方法获得的Ed测量相比,对混凝土湿度条件的测量。此外,建立了估算Ec的公式,s得到了验证。还将在不同湿度条件下测试的正常重量混凝土的模量结果与先前在单独研究中获得的相同体积组成的轻质骨料混凝土的模量结果进行了比较。
    In the case of concrete built into a structure, the static secant modulus of elasticity (Ec,s) is often estimated based on its dynamic value (Ed) measured by the ultrasonic pulse velocity method instead of direct tests carried out on drilled cores. Meanwhile, the prevailing equations applied to estimate Ec,s often overlook the impact of concrete moisture. This study aimed to elucidate the moisture impact across two normal-weight structural concretes differing in compressive strength (51.6 and 71.4 MPa). The impact of moisture content was notably more evident only for the weaker concrete, according to dynamic modulus measurements. In other cases, contrary to the literature reports and expectations, this effect turned out to be insignificant. These observations may be explained by two factors: the relatively dense and homogeneous structure of tested concretes and reduced sensitivity of Ec,s measurements to concrete moisture condition compared to Ed measurements obtained using the ultrasonic method. Additionally, established formulas to estimate Ec,s were verified. The obtained modulus results tested under different moisture conditions of normal-weight concretes were also compared with those of lightweight aggregate concretes of identical volume compositions previously obtained in a separate study.
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  • 文章类型: Journal Article
    宽带科学回声测深仪被认为在浮游动物监测方面具有巨大潜力。在这项研究中,南海两种常见的浮游动物,hopilemahispidumandAceteschinensis,使用宽带科学回声测深仪连续监测。结果表明,芦苇和A.chinensis的回波之间具有明显的体积散射强度(SV)光谱特征。同时,使用k-均值聚类算法对芦苇和A.chinensis的回声进行分类,达到83.4%的准确率。在R.hispidum的标称频率下的SV值变化比A.chinensis的变化更剧烈,这表明R.hispidum的密度变化更显著。这项研究证明了使用宽带科学回声测深仪监测R.hispidum和A.chinensis爆发的优势。
    The broadband scientific echosounder is considered to have great potential for zooplankton monitoring. In this study, two common types of zooplankton in the South China Sea, Rhopilema hispidum and Acetes chinensis, were continuously monitored using a broadband scientific echosounder. The results revealed distinct volume scattering strength (SV) spectral characteristics between the echoes of R. hispidum and A. chinensis. Meanwhile, echoes of R. hispidum and A. chinensis were classified using the k-means clustering algorithm, achieving an 83.4% accuracy rate. The SV value at a nominal frequency of R. hispidum changes more sharply than that of A. chinensis, suggesting that the density of R. hispidum changes more dramatically. This study demonstrates the advantages of monitoring R. hispidum and A. chinensis outbreaks with a broadband scientific echosounder.
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  • 文章类型: Editorial
    暂无摘要。
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  • 文章类型: Journal Article
    许多历史工作都集中在建立地理和生态规则,以广泛解释大小变化的模式。我们使用几何形态计量学和空间统计学检查了斑点鬣狗头骨大小的地理变化。我们量化了头骨的大小变化和性别大小二象性,并评估了温度的影响,降水,土地覆盖类型,和人口密度对头骨大小的影响。我们发现雌性斑点鬣狗平均比雄性稍大。我们对区域差异的分析并未表明性别大小二态性的地理差异。斑点鬣狗的头骨大小随地理位置而变化,但不遵守伯格曼规则。男女最小的个体出现在-5.00°至10.00°和东经28.50°之间,在其他地方发现了更大的个体。尽管斑点鬣狗头骨的大小在某些观点上与栖息地类型和气候指标等变量共同变化,该物种的头骨大小与人口密度的变化最强烈。最高的人口密度与最小的头骨大小有关,可能反映了人口密度高和资源获取之间的关系。这些结果表明,与Bergmann规则相比,能量等效规则可以更好地解释斑点鬣狗头骨大小的地理变化。
    Much historic work has focused on establishing geographical and ecological rules that broadly explain patterns in size variation. We examined geographic variation in Spotted Hyena skull size using geometric morphometrics and spatial statistics. We quantified size variation and sexual size dimorphism of the skull, and evaluated the influence of temperature, precipitation, land cover type, and population density on skull size. We found that female spotted hyenas are slightly larger on average than males. Our analysis of regional differences did not indicate geographic variation in sexual size dimorphism. Skull size of Spotted Hyenas varies with geography but does not adhere to Bergmann\'s Rule. The smallest individuals of both sexes occur between -5.00° and 10.00° latitude and east of 28.50° longitude, with larger individuals being found elsewhere. Although Spotted Hyena skull size co-varies in some views with such variables as habitat type and climate indicators, skull size in this species most strongly co-varies with population density. The highest population densities are associated with the smallest skull size, possibly reflecting a relationship between high population density and access to resources. These results suggest that geographic variation in Spotted Hyena skull size is better explained by the energetic equivalence rule than Bergmann\'s Rule.
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  • 文章类型: Journal Article
    最近的研究表明,心外膜脂肪组织(EAT)是独立的房颤(AF)预后标志物,对心肌功能有影响。在计算机断层扫描(CT)中,EAT体积(EATv)和密度(EATd)是经常用于量化EAT的参数。虽然已发现EATv升高与消融治疗后房颤的患病率和复发相关。较高的EATd与由于脂质成熟停滞引起的炎症以及斑块存在和斑块进展的高风险相关。量化任务的自动化减少了不同观察者在手动量化中引入的读数的可变性,并导致研究的高可重复性和耗时较少的分析。我们的目标是使用深度学习(DL)框架开发EATv和EATd的全自动量化。
    我们提出了一个框架,该框架由图像分类和分割DL模型组成,并执行从为患者采集的所有CT图像中选择EAT图像的任务,以及从上一个任务的输出图像中分割EAT的任务。使用分割掩模估计EATv和EATd以限定感兴趣区域。对于我们的实验,300名患者的数据集被分为两个子集,每个由150名患者组成:数据集1(41,979个CT切片),用于训练DL模型,和Dataset2(36,428CT切片)用于评估EATv和EATd的定量。
    分类模型的精度达到了98%,召回和F1得分,分割模型在平均值(±std。)和中值骰子相似系数得分分别为0.844(±0.19)和0.84。使用评估集(数据集2),我们的方法导致标签和预测的EATV之间的皮尔逊相关系数为0.971(R2=0.943),标签与预测EATd的相关系数为0.972(R2=0.945)。
    我们提出了一个框架,该框架为准确的EAT细分提供了快速而强大的策略,和体积(EATv)和衰减(EATd)量化任务。该框架将对临床医生和其他从业人员有用,用于在患者水平上进行可重复的EAT量化或用于大型队列和高通量项目。
    UNASSIGNED: Recent studies have shown that epicardial adipose tissue (EAT) is an independent atrial fibrillation (AF) prognostic marker and has influence on the myocardial function. In computed tomography (CT), EAT volume (EATv) and density (EATd) are parameters that are often used to quantify EAT. While increased EATv has been found to correlate with the prevalence and the recurrence of AF after ablation therapy, higher EATd correlates with inflammation due to arrest of lipid maturation and with high risk of plaque presence and plaque progression. Automation of the quantification task diminishes the variability in readings introduced by different observers in manual quantification and results in high reproducibility of studies and less time-consuming analysis. Our objective is to develop a fully automated quantification of EATv and EATd using a deep learning (DL) framework.
    UNASSIGNED: We proposed a framework that consists of image classification and segmentation DL models and performs the task of selecting images with EAT from all the CT images acquired for a patient, and the task of segmenting the EAT from the output images of the preceding task. EATv and EATd are estimated using the segmentation masks to define the region of interest. For our experiments, a 300-patient dataset was divided into two subsets, each consisting of 150 patients: Dataset 1 (41,979 CT slices) for training the DL models, and Dataset 2 (36,428 CT slices) for evaluating the quantification of EATv and EATd.
    UNASSIGNED: The classification model achieved accuracies of 98% for precision, recall and F 1 scores, and the segmentation model achieved accuracies in terms of mean ( ± std.) and median dice similarity coefficient scores of 0.844 ( ± 0.19) and 0.84, respectively. Using the evaluation set (Dataset 2), our approach resulted in a Pearson correlation coefficient of 0.971 ( R 2 = 0.943) between the label and predicted EATv, and the correlation coefficient of 0.972 ( R 2 = 0.945) between the label and predicted EATd.
    UNASSIGNED: We proposed a framework that provides a fast and robust strategy for accurate EAT segmentation, and volume (EATv) and attenuation (EATd) quantification tasks. The framework will be useful to clinicians and other practitioners for carrying out reproducible EAT quantification at patient level or for large cohorts and high-throughput projects.
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  • 文章类型: Journal Article
    背景:来自各种来源的胶原肽在体外和临床试验中都显示出对健康和福祉的益处。然而,金枪鱼胶原蛋白肽对皮肤健康的研究很少。
    目的:研究来自金枪鱼的胶原蛋白肽(Katsuwonuspelamis和Thunnusalbacares)对皮肤健康的影响,利用体外生物学研究和随机对照试验。
    方法:在胶原和弹性蛋白合成和衰老细胞抑制方面评价了人真皮原代成纤维细胞的体外生物学研究。一个随机的,安慰剂对照,对72名妇女进行了双盲临床试验,这些妇女被随机分配接受金枪鱼胶原蛋白肽(n=36)或安慰剂(n=36)口服8周和2周后通过测量皮肤水合作用,经皮水分流失(TEWL),皮肤弹性,和皮肤密度。
    结果:体外生物学效应表明,在增加胶原蛋白和弹性蛋白合成以及减少衰老细胞方面具有剂量依赖性的阳性结果。对胶原蛋白和衰老细胞的影响在高浓度时趋于稳定。一项临床试验表明,测试组皮肤水合作用显着增加,弹性,和密度,与基线相比,TEWL下降。除了面部的TEWL之外,测试组和安慰剂组在8周时显示出所有参数的统计学显著差异。即使在停药2周后,所有的积极作用也基本上得以保留。
    结论:这些发现证明了金枪鱼胶原蛋白肽促进人类皮肤健康的巨大潜力,作为一种潜在的营养品,有必要进行进一步的调查。
    BACKGROUND: Collagen peptides from various sources demonstrate benefits in health and well-being both in vitro and in clinical trials. However, there is a scarce study of collagen peptides from Tuna on skin health.
    OBJECTIVE: To investigate the impact of collagen peptides derived from Tuna (Katsuwonus pelamis and Thunnus albacares) on skin health, utilizing in vitro biological studies and a randomized controlled trial.
    METHODS: In vitro biological studies on human dermal primary fibroblasts were evaluated in terms of collagen and elastin synthesis and senescent cell inhibition. A randomized, placebo-controlled, double-blind clinical trial was conducted on 72 women who were randomly assigned to receive either tuna collagen peptides (n = 36) or a placebo (n = 36) orally for 8 weeks and 2 weeks post-ingestion by measuring skin hydration, transepidermal water loss (TEWL), skin elasticity, and skin density.
    RESULTS: In vitro biological effects demonstrated dose-dependent positive results in increasing collagen and elastin synthesis and reducing senescent cells. The effects on collagen and senescent cells plateaued at high concentrations. A clinical trial showed that the test group experienced a significant increase in skin hydration, elasticity, and density, along with a decrease in TEWL compared to the baseline. The test and placebo groups showed statistically significant differences at 8 weeks for all parameters except for the TEWL at the face. All positive effects were substantially retained even after 2 weeks of discontinuation.
    CONCLUSIONS: These findings demonstrate the significant potential of tuna collagen peptides to promote human skin health, warranting further investigation as a potential nutraceutical.
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