Reducing noise in computed correlation functions using techniques from signal processing

Time correlation functions invariably suffer from random noise, especially at longer time intervals for which fewer data pairs are available. This noise is particularly of concern when calculating correlations that cannot be averaged over per-molecule contributions, such as stress in molecular simulations. In this work, a set of methods based in signal processing has been developed to reduce the inherent noise that is present in time- and frequency-domain representations of correlation functions. The stress time autocorrelation function, which leads to stress relaxation modulus and complex modulus, is used as an example. The difference between initial and final values of a time correlation function over a finite time domain is found to create so-called ‘leakage’ of noise from disallowed into harmonic frequencies during fast Fourier transformation. Decreasing this leakage effect through reflection to negative time and through applying a window function reduces noise levels significantly. Removing frequency components of insignificant magnitudes also provides significant noise reduction. Applying moving averages in the frequency and time domains also contributes to noise reduction. Specific results obtained by applying these methods to a model asphalt system enable more clear physical interpretations of the underlying relaxations after dramatic noise level reductions were attained.     

人参养荣汤联合穴位贴敷对冠心病PCI术后患者血脂、心功能和Th1/Th2型细胞因子的影响

摘要 目的：观察人参养荣汤联合穴位贴敷对冠心病经皮冠状动脉介入术（PCI）后患者血脂、心功能和辅助性T细胞1（Th1）/Th2型细胞因子的影响。方法：选取2020年2月~2022年12月期间在我院接收的冠心病PCI术后患者142例。采用双色球法将患者分为对照组（71例,常规西医治疗+穴位贴敷）和实验组（71例,对照组的基础上接受人参养荣汤）,均治疗4周。观察并比较两组中医证候积分、心功能指标[左心室射血分数（LVEF）和每分心输出量（CO）]、血脂四项指标[三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）、总胆固醇（TC）]、Th1/Th2型细胞因子[子γ干扰素（IFN-γ）、白细胞介素（IL）-2、IL-4、IL-10]。同时记录两组治疗结束半年内心血管不良事件发生率。结果：两组治疗后主症评分、次症评分、总评分下降,实验组低于照组,数据比较有差异（P<0.05）。治疗后两组LVEF和CO均升高,实验组高于对照组,数据比较有差异（P<0.05）。与对照组相比,实验组治疗后HDL-C高于对照组,TG、TC、LDL-C低于对照组,数据比较有差异（P<0.05）。与对照组相比,治疗后实验组的IL-4、IL-10更高,而IFN-γ、IL-2更低,数据比较有差异（P<0.05）。两组心血管不良事件发生率对比未见统计学差异（P>0.05）。结论：人参养荣汤联合穴位贴敷用于冠心病PCI术后患者,可改善患者的血脂和心功能,调节Th1/Th2型细胞因子,促进临床转归。     

乌龟外周血细胞的显微和超微结构

乌龟血细胞的显微和超微结构研究表明;在外周血细胞中,可分辨出红细胞、单核细胞、淋巴细胞、血栓细胞、嗜酸性粒细胞、嗜碱性粒细胞、嗜中性粒细胞等7种细胞.红细胞核圆形,胞质均匀无细胞器.单核细胞的特征是核内异染色质多聚集于周边,胞质中含有许多囊泡.淋巴细胞的核质比例大.血栓细胞以具细长的指状突起,基本无细胞器为其特征.嗜酸性粒细胞仅含一种圆形颗粒,颗粒质地均匀,电子致密,大小不等.嗜碱性粒细胞颗粒环绕在胞核周围,有三种电子密度、颗粒大小不一的类型.嗜中性粒细胞含有两种电子密度、形态不一的颗粒.       

A continuum mechanics model for the Fåhræus-Lindqvist effect

The decrease in apparent relative viscosity that occurs when blood is made to flow through a tube whose diameter is less than about 0.3 mm is a well-known and documented phenomenon in physiology, known as the Fåhræus-Lindqvist effect. However, since the historical work of Fåhræus and Lindqvist (Amer. J. Physiol. 96(3): pp. 562–568, 1931), the underlying physical mechanism has remained enigmatic. A widely accepted qualitative explanation was provided by Haynes (Amer. J. Physiol. 198, pp. 1193–1200, 1960) according to which blood flows in microvessels with a core-annulus structure, where the erythrocytes concentrate within a central core surrounded by a plasma layer. Although sustained by observations, this conjecture lacks a rigorous deduction from the basic principles of continuum dynamics. Moreover, relations aimed to reproduce the blood apparent relative viscosity, extensively used in micro-circulation, are all empirical and not derived from the analysis of the fluid mechanical phenomena involved. In this paper, we apply the recent results illustrated in Guadagni and Farina (Int. J. Nonlinear Mech. 126, p. 103587, 2020), with the purpose of showing that Haynes’ conjecture, slightly corrected to make it more realistic, can be proved and can be used to reach a sound explanation of the Fåhræus-Lindqvist effect based on continuum mechanics. We propose a theoretical model for the blood apparent relative viscosity which is validated by matching not only the original experimental data reported by Fåhræus and Lindqvist (Amer. J. Physiol. 96(3), pp. 562–568, 1931), but also those provided by several subsequent authors.     

草鱼肾脏和脾脏血细胞发育过程的观察

鱼类肾脏、脾脏是机体造血的主要器官。印迹涂片显示:草鱼肾脏和脾脏内血细胞的发育过程大致经历了三个阶段,即原始阶段、幼稚阶段、成熟阶段。本文着重描述了各阶段细胞的形态特征井对草鱼血细胞的发育及命名等问题作了初步的探讨。       

Preanalytical errors on zinc concentrations caused by single-use gloves

Preanalytical errors causing specimen contamination with zinc (Zn) are disastrous for routine medical diagnostics or scientific studies. The aim of the study presented here is to simulate contamination possibilities when using single-use gloves.The ability to release Zn into the specimen was tested using nitril (A), vinyl (B) and latex (C) gloves with 15 (14) replications. In our first approach, a 1 × 1 cm piece of the glove’s fingertip was incubated for 10 min with serum. Our second approach imitated a very short contact of serum to the glove’s material by letting serum run over the glove from a pipette for 3 cm distance into a tube. The effect of gloves’ contact to liver tissue was examined using glove C only: a block of liver tissue was touched once at one side producing an experimental fingerprint. Zn was analyzed in serum and liver wet weight (ww) using ICP-MS; the basal serum/liver Zn concentration was set as zero for calculation. The calculated addition of Zn is given as median (p25 - p75).The first approach led to distinct contamination with Zn (in μg/L) being evident from all three types of gloves, but depended markedly from the type of material: A: 176.5 (129.7–204); B: 975.1 (663.6–1164.3); C: 2112 (1685–2516). Imitating a very short contact of serum to the glove’s surface resulted in an additional Zn concentration of 105.7 (70.4–168.8), 56.2 (-13.5–121.4) and 955.7 (746–1159) μg/L using gloves A, B and C, respectively. A single fingerprint on liver tissue using glove C resulted an addition of 3995 (861–6435) μg Zn/kg liver ww.The data underline that the dimension of preanalytical contamination of blood and tissue samples for Zn analysis via single-use gloves is relevant for routine diagnostics and scientific studies. Critical steps and possibilities to minimize these effects should be considered seriously for specimen handling in routine laboratory diagnostics as well as in scientific studies to avoid preanalytical errors and, finally, misinterpretation of the data.     

Immunomodulation-mediated anticancer activity of a novel compound from Brugmansia suaveolens leaves

Immunomodulation activity-guided fractionation of ethanol extract of Brugmansia suaveolens leaves was carried out to isolate a novel compound SUPH036-022A (1) by co-culturing the test fraction/compound activated PBMC with MCF7 and A549 cancer cell lines. Assessment of immune markers in PBMC, and analysis of apoptosis markers and cell cycle was carried out for cancer cells. The structure of the isolated compound was elucidated by spectral analysis. Compound 1 enhanced the secretion of immune markers, IL-2 and IFN-γ, from PBMC. Further, compound 1 treated PBMC increased cell death in MCF7 and A549 cell lines and induced ROS production and mitochondrial membrane perturbation, leading to apoptosis. Flow cytometry analysis revealed; compound 1 stimulated PBMC to cause a five-fold increase in cell cycle perturbations in the sub-G1 stage of cancer cells as compared to the negative control. The compound, in the absence of PBMC, only had a weak cytotoxic activity against these cell lines. Thus, compound 1 is a novel lead for immunomodulation-mediated anticancer activity.     

母亲、新生儿和收集相关因素对高质量脐血的影响

目的:探讨母亲、新生儿和收集相关因素对高质量脐血(high-quality cord blood units,HQCBUs)的影响。方法:用logistical回归模型回顾性分析广州脐血库(Guangzhou Cord Blood Bank,GZCBB)库存的4613例脐血的母亲、新生儿和收集相关因素,所有脐血均严格按照操作规程进行供者选择、采集、运送、处理、检测和冻存。结果:影响HQCBUs的因素包括分娩时顺产、孕周大于37周、新生儿为女性、较重的体重(3500 g)、脐血体积大(80 m L)、运送耗时短(12 hr)。α-地贫携带者对处理后细胞数(postprocessing total nucleated cell count,p-TNCC)1.25×109和CD34+细胞数6.01×106有影响,而羊水粪染和母亲分娩年龄小于25岁分别对p-TNCC1.25×109和细胞集落形成单位(colony forming units,CFUs)23.24×105有影响。结论:我们鉴定出影响HQCBUs的因素,为GZCBB更新脐血采集标准、优化处理程序提供参考依据,有助于提高HQCBUs的数量和比例及有效利用脐血库的资源。     

Differential circadian pattern of water and Na excretion rates in the metabolic syndrome

This study comparatively investigated the chronobiology of water and Na excretion rates (W-ExcR and Na-ExcR) in 46 non-diabetic metabolic syndrome (MS) patients. The circadian pattern of W-ExcR was independently associated with the nocturnal dipping of systolic blood pressure (β?=??3.1). During oral glucose tolerance test, the rise in plasma insulin (β?=?34.0) and the insulinogenic index (β?=?4.1) were independently associated with the day/night ratio of W-ExcR. The circadian pattern of Na-ExcR was not significantly associated with the latter variables. This study strongly suggests that the chronobiology of mechanisms involved in the regulation of water excretion may be more specifically altered in the MS.     

Blood groups and red cell enzymes of the Ross River (Northern Tuchone), and Upper Liard (Slave) Indians

A survey of nine blood group systems was conducted as part of a study of health and nutrition among two Athapsakan groups of the Yukon Territory, Canada. Most of the samples were also analyzed for hemoglobin patterns and G-6-PD variants. The only significant difference in allelic frequencies between the two populations occurred at the P locus. An apparent deficit in the observed frequency of type A₁, and hence a departure from equilibrium, at Upper Laird could not be tested for significance due to insufficient degrees of freedom.