Theoretical investigation of nonlinear optical behavior for rod and T-Shaped phenothiazine based D-π-A organic compounds and their derivatives

The exploration of novel materials with excellent nonlinear optical (NLO) features is an area of frontline investigation for scientific community from technological point of view. This study reports the novel phenothiazine-based rod-shaped and T-shaped NLO molecules which are quantum chemically designed from synthesized compounds: rod-shaped (CFA and CBA) and T-shaped (CTA, CCA and CPA). Structural tailoring was performed on D-π-π-A centered CPA chromophore and the effect of various π-spacers, as well as solvents on NLO response properties is investigated. Density functional theory (DFT) along with time dependent DFT (TDDFT) calculations have been executed at B3LYP/6-311G(d,p) functional to examine entire analysis. Results showed a smaller energy gap in structurally modified compounds as compared to reference CPA. Global reactivity parameters analysis revealed smaller hardness and larger softness values in T-shaped compounds. UV–Vis analysis of investigated molecules displayed a red shift in absorption maximum value as compared to CPA. Natural bond orbital (NBO) and frontier molecular orbital (FMO) analysis revealed the stability and intra-molecular electron transferring (ICT) process in investigated molecules. ICT showed the effective charge shift from donor to acceptor via π-spacers. Overall, promising NLO response exists in gas phase and different solvents (acetonitrile, ethyl alcohol and water). Interestingly, proposed molecule CPP presented a maximum value of linear polarizability < α > as 1518.23 a.u and first hyperpolarizability (β_tot) as 755322.39 a.u in acetonitrile solvent. In short, entitled chromophores exhibited excellent NLO properties due to their lower charge transport resistance. This NLO study may open a new topic for researchers to discover novel NLO for hi-tech submissions of modern era.     

Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale

Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.     

Comparative Studies of Selected Criteria Enabling Optimization of the Extraction of Polar Biologically Active Compounds from Alfalfa with Supercritical Carbon Dioxide

The aim of this research was to provide crucial and useful data about the selection of the optimization criteria of supercritical carbon dioxide extraction of alfalfa at a quarter-technical plant. The correlation between more general output, including total phenolics and flavonoids content, and a more specified composition of polar constituents was extensively studied. In all alfalfa extracts, polar bioactive constituents were analyzed by both spectrometric (general output) and chromatographic (detailed output) analyses. Eight specific phenolic acids and nine flavonoids were determined. The most dominant were salicylic acid (221.41 µg g⁻¹), ferulic acid (119.73 µg g⁻¹), quercetin (2.23 µg g⁻¹), and apigenin (2.60 µg g⁻¹). For all seventeen analyzed compounds, response surface methodology and analysis of variance were used to provide the optimal conditions of supercritical fluid extraction for each individual constituent. The obtained data have shown that eight of those compounds have a similar range of optimal process parameters, being significantly analogous for optimization based on total flavonoid content.     

基于核酸的纸基荧光生物传感器的设计及应用

纸基生物传感器由于其具有成本低、操作方便、生物可降解、识别元件用量低等优点,近年来受到了广泛的关注。其中,以功能核酸作为识别元件的纸基荧光生物传感器具有较高的灵敏度、瞬时响应以及实时检测等特性,在便携式传感设备方面展现出巨大的潜力。此外,将核酸作为识别元件的纸基无细胞蛋白合成平台,通过条件合成的报告荧光蛋白可实现对病毒、重金属等目标物的特异性检测,具有良好的应用前景。首先,本文介绍了基于核酸的纸基荧光生物传感器的设计,特别是基于核酸的识别元件与纸基材料的结合方式。其次,总结了基于核酸的纸基荧光生物传感器在临床诊断、食品安全检测、环境污染物检测等不同领域的最新研究进展,讨论了其优势与局限性。最后,探讨了基于核酸的纸基荧光生物传感器的发展方向与应用前景,以期为相关领域的研究提供参考。     

Frequency-selective quantitation of short-echo time 1H magnetic resonance spectra

Accurate and efficient filtering techniques are required to suppress large nuisance components present in short-echo time magnetic resonance (MR) spectra. This paper discusses two powerful filtering techniques used in long-echo time MR spectral quantitation, the maximum-phase FIR filter (MP-FIR) and the Hankel-Lanczos Singular Value Decomposition with Partial ReOrthogonalization (HLSVD-PRO), and shows that they can be applied to their more complex short-echo time spectral counterparts. Both filters are validated and compared through extensive simulations. Their properties are discussed. In particular, the capability of MP-FIR for dealing with macromolecular components is emphasized. Although this property does not make a large difference for long-echo time MR spectra, it can be important when quantifying short-echo time spectra.     

The regulation of biothiol-responsive performance and bioimaging application of benzo[c][1,2,5]oxadiazole dyes

The different oxidation states of sulphur atom play a significant role on functional materials. In this work, a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to determine thiol-containing amino acids. The result of selectivity experiments showed they detected the cysteine and homocysteine under physiological condition with negligible interference from other amino acids. In comparison to the thioether dye, the sulphone-based dye exhibited much faster response time for Cys and Hcy. However, the sulphone restricted its thiol-reactivity and bioimaging performance in living cells. By reducing the oxidation state of sulphur atom, we amazedly found that the sulfoxide-based dye still maintained high selectivity ultrafast response time for Cys/Hcy under physiological condition. It was worth mentioning that it also had high reactivity and good bioimaging performance that sulfone compounds did not have.     

装备使用与保障研究数据的生成方法研究

装备使用与保障数据是开展装备科学研究的重要依据,而由于管理不善、保密、样本过少等原因常常导致相关数据缺少应有的积累,无法满足实际研究的需要。为了克服这一困难,文章提出通过算法生成数据予以解决。首先根据数据的应用特性,将装备使用与保障数据看作简单数据、规律已知数据和规律未知数据三类,分别制定生成策略。对于简单数据和规律已知数据,通过已有的商用软件或简单的自定义方法生成;对于规律未知数据,采用模式注入或特性继承的方法生成。在某大型装备管理综合信息系统的设计开发中,对这些生成方法进行了工程实践,结果表明了方法的正确性和可行性。     

太阳运动模拟平台的单片机控制

针对用太阳运动模拟平台实现太阳运行位置的全面预测和重现这一问题,提出了采用单片机对该平台进行控制,电机通过变频实现不同时间段不同速率运动模拟太阳运行轨迹的方法。根据输入日期计算出太阳的高度角和方位角,并转换为驱动电机的脉冲数和频率,电机带动执行机构运动使模拟光源到达预定位置。用编码器测量电机实际脉冲,定期进行误差校正来提高系统的稳定性和精度,减少误差。经过实验验证,该平台能够使模拟光源按照预计的轨迹运动,得出该方法是可行的,所设计的程序具有可靠性的结论。     

Fenna-Matthews-Olson捕光复合物中的冗余结构

研究了绿色硫细菌中捕光天线复合物Fenna-Matthews-Olson的一个子单元和反应中心的能量传递.通过细菌叶绿素分子的能量和耦合强度,构建了包含反应中心的哈密顿量及约化模型.通过级联运动方程研究了不同分子间和反应中心的激子布居演化.计算了Fenna-Matthews-Olson及其约化模型的二维三阶光子回波谱,获得能量传榆过程中不同激子态间的相干性.结果表明在能量捕获过程中,Fenna-Matthews-Olson复合物存在冗余结构.