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A method, quantitative analysis of multicomponents by single marker (QAMS), was established and fully verified based on high-performance liquid chromatography (HPLC) for simultaneous determination of six chromone indicators of Saposhnikoviae Radix (SR). In the present study, cimifugin (C), 5-O-methylvisamminol (V), hamaudol (H), and their corresponding glycosides, prim-O-glucosylcimifugin (GC), 4′-O-β-D-glucosyl-5-O-methylvisamminol (GV), and sec-O-glucosylhamaudol (GH), were selected as bioactive constituents and indicators for the quality evaluation of SR. GV was chosen as the unique reference standard, and relative correction factors (RCF) between GV and the other five chromones were calculated. The feasibility of QAMS for the analysis of chromones was investigated by comparing with the traditional external standard method (ESM). Furthermore, the method was proven to have accuracy (96.98%–102.50%), repeatability (RSD <3%), stability (RSD <3%), precision (RSD <3%), and desirable linearity (R2 ≧0.9999). Subsequently, 55 batches of commercial SR from different regions were determined by QAMS, and their contents were analyzed by principal component analysis (PCA), correlation analysis, and hierarchical cluster analysis (HCA), respectively. Based on the results, a more refined quality standard of commercial SR was proposed: SR was qualified when the total contents of six chromones were greater than 3 mg·g−1. Furthermore, SR could initially be regarded as a superior medicine when it satisfied both conditions at the same time: the total content of GC, C, GV, V, GH, and H was greater than 8 mg·g−1, and the proportion of the total content of C, V, and H was greater than 10%. This study demonstrated that the quality of SR could be successfully evaluated by the developed QAMS method; meanwhile, valuable information was provided for improving the quality standard of SR. [ABSTRACT FROM AUTHOR]

It provided a powerful new way for predicting the growth trend of malignant tumor and assisting the treatment of cancer patients. Firstly, a one-dimensional mathematical model for the dynamic proliferation of malignant tumors is established on the premise of related simplification and hypothesis. Secondly, according to the Lie symmetry theory, we deduce the multigroup allowed infinitely small generating elements of partial differential equations and obtain the analytic form of the exact invariant solution. Finally, the influence of the model condition parameters (oxygen concentration and inhibitor concentration) on the tumor multiplication time index T is analyzed and discussed. The results showed that when the concentration of the nutrient substance is higher than the critical concentration, the multiplication time of the tumor region approximately decreased firstly and then increased in the linear form about tumor radius under different oxygen concentrations, and at the same radius, the oxygen concentration is lower, and the multiplication time is longer; the multiplication time of the tumor region approximately decreased in the exponential form about tumor radius under different inhibitor concentrations, and at the same radius, the inhibitor concentration is higher, and the multiplication time is bigger, which are consistent with the experimental and clinical observation. [ABSTRACT FROM AUTHOR]

Branched fatty acid esters of hydroxy fatty acids (FAHFAs) are an important family of endogenous lipids, possessing antidiabetic and anti-inflammatory functions. Therefore, analysis of FAHFAs in biological samples obtained under healthy and disease states can uncover underlying mechanisms of various relevant disorders (e.g., diabetes and autoimmune diseases). Up to now, due to their extremely low abundance, the determination of the changed levels of these species is still a huge challenge, even though great efforts have been made by utilizing liquid chromatography-tandem mass spectrometry with or without derivatization. Herein, we described a novel method for analysis of FAHFAs present in lipid extracts of biological examples after solid-phase extraction and chemical derivatization with one authentic FAHFA specie as an internal standard based on the principles of multi-dimensional mass spectrometry-based shotgun lipidomics. The approach possessed marked sensitivity, high specificity, and broad linear dynamic range of over 3 orders without obvious matrix effects. Moreover, after chemical derivatization, the molecular masses of FAHFAs shift from an overlapped region with ceramide species to a new region without overlaps, removing these contaminating signals from ceramides, and thereby reducing the false results of FAHFAs. Finally, this novel method was successfully applied for determining FAHFAs levels in varieties of representative biological samples, including plasma from lean and overweight/obese individuals of normoglycemia, and tissue samples (such as liver and white adipose tissue from diabetic (db/db) mice). We revealed significant alterations of FAHFAs in samples under patho(physio)logical conditions compared to their respective controls. Taken together, the developed method could greatly contribute to studying altered FAHFA levels under a variety of biological/biomedical conditions, and facilitate the understanding of these lipid species in the patho(physio)logical process. Image 1 • Developed a shotgun lipidomics approach with solid-phase extraction and chemical derivatization for quantitative analysis of FAHFA species. • Compared to previous methods, a smaller amount of biological sample is used. • Successfully applied the developed method for determining FAHFA in representative biological samples. [ABSTRACT FROM AUTHOR]

In this study, a valid and comprehensive evaluation method for assessing the quality of Desmodium styracifolium (Osb.) Merr has been established, based on analysis of high-performance liquid chromatography fingerprint combined with the similarity analysis (SA), hierarchical cluster analysis (HCA), principal component analysis (PCA), discriminant analysis (DA) and the quantitative analysis multi-components by single marker (QAMS) method. Eleven peaks of the common model were obtained and analyzed using SA, HCA, PCA and DA analysis. These methods indicated a similar conclusion that 31 batches of D. styracifolium samples were categorized into two clusters basically coincident with their geographical regions of origin. Four peaks were identified as schaftoside, isoorientin, isoschaftoside and isovitexin. Schaftoside was selected as the internal standard, and the relative correction factors between schaftoside and the other three flavonoids were calculated using the QAMS method. The accuracy of the QAMS method was verified by comparing with the results calculated by the external standard method. No significant difference between the two methods was found. In conclusion, the established methods were scientifically applied in the quality evaluation of D. styracifolium. [ABSTRACT FROM AUTHOR]

Acquisition of classical absorption spectra of liquids in the mid-IR range with quantum cascade lasers (QCLs) is often limited in sensitivity by noise from the laser source. Alternatively, measurement of molecular dispersion (i.e., refractive index) spectra poses an experimental approach that is immune to intensity fluctuations and further offers a direct relationship between the recorded signal and the sample concentration. In this work, we present an external cavity quantum cascade laser (EC-QCL) based Mach–Zehnder interferometer setup to determine dispersion spectra of liquid samples. We present two approaches for acquisition of refractive index spectra and compare the qualitative experimental results. Furthermore, the performance for quantitative analysis is evaluated. Finally, multivariate analysis of a spectrally complex mixture comprising three different sugars is performed. The obtained figures of merit by partial least squares (PLS) regression modelling compare well with standard absorption spectroscopy, demonstrating the potential of the introduced dispersion spectroscopic method for quantitative chemical analysis. [ABSTRACT FROM AUTHOR]

Pantoprazole sodium sesquihydrate, is a proton pump inhibitor, was analyzed by using UV spectrophotometry. The quantification of pantoprazole sodium sesquihydrate in distilled water was performed in the wavelength range of 290 nm at 20 μgmL-1. The linearity range is 5-35 μgmL-1 by using UV spectrophotometry. The developed method was applied directly and easily to the analysis of the pantoprazole sodium sesquihydrate in bulk and pharmaceutical tablet preparations. The developed method was completely validated according to ICH guidelines. The accuracy of the developed method was calculated in terms of percentage recovery (99.20-101.21%) and %RSD values less than 1% were found in precision. The LOD and LOQ were 0.989 and 1.954 μgmL-1, respectively. Because of simplicity, accuracy and cost-effectiveness, this validated method is helpful for a daily laboratory analysis of pantoprazole sodium sesquihydrate. [ABSTRACT FROM AUTHOR]

Despite the pivotal roles played by halide ions (e. g., Cl− and Br−) in directing the evolution of seeds into metal nanocrystals with diverse shapes, it is still unclear how halides affect the reduction kinetics of a salt precursor and thus the outcome of a synthesis. Here we report a quantitative analysis of the multiple roles played by halides in controlling the growth behaviors of Pd seeds with cubic and octahedral shapes, respectively. Our quantitative measurements clearly indicate the existence of a transition point around 10−3 mM min−1 for the reduction rate, which separates the reduction into two distinctive pathways (solution versus surface) for the formation of completely different products. More significantly, we demonstrate that the speciation, reduction kinetics, and reduction pathway of a Pd(II) precursor can all be manipulated by varying the type and/or amount of halides introduced into a synthesis for the deterministic formation of a specific product. This work represents a critical step forward in achieving a quantitative understanding of the multiple roles of halides involved in the shape‐controlled synthesis of Pd nanocrystals, with the knowledge potentially extendible to other noble metals and their alloys. [ABSTRACT FROM AUTHOR]

This paper mainly investigates the influence of self-connection delay on bifurcation in a fractional neural network. The bifurcation criteria for the proposed systems with self-connection delay or without self-connection delay is figured out using time delay as a bifurcation parameter, respectively. The effects of self-connection delay on bifurcation in a fractional neural network are ascertained in this paper. Comparative analysis indicates that the stability performance of the proposed fractional neural networks is overly undermined by self-connection delay, which cannot be disregarded. In addition, the impact of fractional order on the bifurcation point is revealed. To highlight the proposed original results, two numerical examples are finally presented. [ABSTRACT FROM AUTHOR]

The applications of dextran depend not only on the molecular weight but also on the types and number of branches. In this study, dextran generated from Leuconostoc mesenteroides (L.M.CICC-20724) was characterized by fourier-transform infrared spectrum and nuclear magnetic resonance spectroscopy. Our analyses showed that dextran was a polysaccharide composed of d -glucose units with predominantly α(1 → 6) linkages in the main chain and few α(1 → 3) linkages in the branch. Periodate oxidation, a classic chemical method, was usually combined with Smith degradation and gas chromatography to analyze glycosidic linkages in polysaccharide quantitatively. In this study, we calculated the exact straight-chain/branched-chain ratio in the dextran using periodate oxidation only. The ratios obtained by periodate oxidation only were compared to the ratios obtained by nuclear magnetic resonance. The results showed that the ratios of the two groups were nearly equal, and the average relative error between the two groups was 0.83%. This method was evaluated and found to be accurate and stable. This technique provided a convenient and straightforward chemical method for the quantitative analysis of the straight-chains and branched-chains in polysaccharides which had a similar structure. The ratios during the enzymatic synthesis process of dextran were analyzed by this method and were found to be stable with a high level of approximately 95% on average. • Dextran produced by L.M.CICC-20724 contained α(1 → 6) linkages in the main chain and few α(1 → 3) linkages in the branch. • Periodate oxidation was accurate for quantitative analysis of straight-chain/branched-chain ratio in polysaccharides. • The straight-chain/branched-chain ratios during the whole enzymatic synthesis were found to be stable with 95% on average. [ABSTRACT FROM AUTHOR]

Pantoprazole sodium (PPZS) is a selective proton pump inhibitor used in the prevention and treatment of gastric acid-related diseases. Six potentially genotoxic impurities (PGIs) are involved in 5-difluoromethoxy-2-mercapto-1H-benzimidazole (DMBZ), which is the starting material of PPZS. To date, no suitable method has yet been developed for PGI separation and quantification at the threshold of toxicological concern levels. In this study, a sensitive and reliable liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitative analysis of six PGIs in DMBZ according to the guidelines of the International Council for Harmonization (ICH). The calibration curves showed good linearity within the studied range, and the correlation coefficient of fitting exceeded 0.998 for each impurity. The sensitivity of the proposed method was in the range of 0.6–10.0 ng/mL. Good recoveries were observed in the range of 94.32%–107.43% with RSD values below 6.5%. Quantitative analysis of impurities in substance batches of DMBZ showed the high efficiency of the developed method at a low level. Hence, the proposed method is practical and useful in the detection and qualification of PGIs in DMBZ and may be applied to ensure the safe use of PPZS in clinical treatment. [ABSTRACT FROM AUTHOR]

Background: Early recognition and management of acid‐base, fluid, and electrolyte disorders are crucial for the maintenance of health and performance in equine athletes. Objectives: To analyze changes in acid‐base and electrolyte status associated with exercise during cross‐country competitions at different levels using traditional and quantitative approaches. Animals Thirty‐eight eventing horses. Methods: Prospective observational study. Jugular venous blood samples were collected before and after the cross‐country test of 25 international eventing competitions ranging from 2‐star (formerly 1‐star) to 5‐star (formerly 4‐star) level. Blood gas analysis was performed to determine pH, pCO2, Na+, Cl−, and K+ and calculate HCO3−, tCO2 base excess (BEECF), anion gap (AG), strong ion difference calculated from Na+, K+, Cl−, and lactate− (SID4), strong ion difference calculated from Na+, K+, and Cl− (SID3), strong ion gap (SIG), and total nonvolatile weak buffer concentration (Atot). Postexercise acid‐base imbalances, diagnosed on the basis of the traditional approach, and the simplified strong ion model were compared. Results: Significant decreases in pH, Cl−, SID4, pCO2, HCO3−, tCO2, and BEECF as well as increases in K+, SID3, AG, TP, and Atot were observed between pre‐ and postexercise samples. The changes in acid‐base parameters were significantly affected by the competition level. Using the strong ion approach, a higher proportion of horses was diagnosed with postexercise metabolic acidosis. Conclusions and Clinical Importance: Regarding the complex acid‐base changes in horses competing at cross‐country competitions, the quantitative approach provided a more detailed analysis of the different factors contributing to acid‐base balance than did the traditional approach. [ABSTRACT FROM AUTHOR]

We investigated crude Aster tataricus, vinegar‐processed Aster tataricus, honey‐processed Aster tataricus, and steamed Aster tataricus as a case study and developed a comprehensive strategy integrating quantitative analysis and chemical pattern recognition methods for the evaluation and differentiation of Aster tataricus from different regions, as well as related processed products. In the study, 15 batches of raw Aster tataricus collected from seven provinces were analyzed. A sensitive and rapid ultra‐high performance liquid chromatography with tandem mass spectrometry method for simultaneous determination of 15 compounds was established to evaluate the quality of raw and processed Aster tataricus. Furthermore, multivariate statistical techniques were applied to compare the differences among Aster tataricus samples. As a result, the herbs collected from seven provinces were divided into two categories, and chlorogenic acid was the most important component distinguishing between the regions. Moreover, all of the raw and processed samples were classified by partial least squares discriminant analysis based on the 15 analyzed compounds. Results showed that raw Aster tataricus, vinegar‐processed Aster tataricus, honey‐processed Aster tataricus, and steamed Aster tataricus were clustered in four different areas. Shionone, chlorogenic acid and kaempferol were the significant constituents differentiating the raw and differently processed Aster tataricus samples. [ABSTRACT FROM AUTHOR]

Dimethylsilanediol (DMSD) is a highly water-soluble degradation product of dimethylsiloxane oligomer and polymer materials that may be found in the environment. In this project, we have developed a water analysis method for DMSD based on liquid chromatography-triple quadrupole tandem mass spectrometry (LC/QQQ MS/MS) using 13C-DMSD as an internal standard with and without solid phase extraction (SPE). This included the modification of SPE extraction method for water samples with colloidal particles that may plug the SPE cartridge, the use of a water-based solvent mixture for DMSD elution to promote better ionisation in instrumental analysis and optimisation of instrumental operation conditions for higher sensitivity in QQQ MS/MS analysis. The water method was successfully applied for analysis of DMSD in soil, sediment and biosolids by coupling the water extraction of DMSD from solid samples with the pre-column SPE extraction of the water extracts. The method detection limit (MDL) for direct water analysis was found to be as low as 2 μg L−1, while the current MDLs for sediment, soil and biosolids are in the range of 10 to 100 ng g−1 dw. The matrix spike recovery varied from 79% to 99% for all samples, confirming its general validity of the method. Compared with the published methods, this method requires less sample processing and has lower MDLs for DMSD analysis in environmental samples. [ABSTRACT FROM AUTHOR]

Rice-flavor baijiu is a traditional Chinese liquor that is manufactured using a solid-state saccharification process. In the present study, we investigated the role of the process in making of rice-flavor baijiu using chemical and biological quantitative analysis approaches. More than 70% of starch in rice decomposed to glucose after saccharification. In addition, the number of fungal cells, saccharification activity, and lactic acid concentration increased. Rhizopus oryzae was identified as the major fungus proliferating under saccharification based on denaturing gradient gel electrophoresis analysis targeting the internal spacer transcribed region. Lactic acid bacteria were not detected by 16S rRNA gene-based next-generation sequencing analysis during saccharification. Conversely, R. oryzae , isolated from xiaoqu, exhibited a capacity to produce lactic acid. The results imply that the solid-state saccharification is essential not only for saccharification but also for the culture of R. oryzae , which promote saccharification activity and lactic acid production. We also investigated the most appropriate temperature for solid-state saccharification and 35°C was the optimum temperature for R. oryzae cultivation, enzyme production, and saccharification. The results could facilitate the efficient and stable manufacture of rice-flavor baijiu. [ABSTRACT FROM AUTHOR]

The International Standard Organization (ISO) 20289 provides a method for determining the elemental concentration of impurities dissolved in water samples. It exploits total reflection X‐ray fluorescence (TXRF) spectroscopy to measure a dried residue on an X‐ray reflector. The scope is to provide a chemical metrology for quantitative analysis to obtain traceable results within a defined degree of accuracy and precision according to good practice and in compliance with ISO 17025. Target users include technicians working in laboratories who perform routine analysis of large numbers of samples. The method is specifically focused on determining elements dissolved in drinking, surface and ground water, but it can be also extended to waste waters and eluates if dilution steps are considered. The standard includes the description of all reagents, standards, and materials, including suitable reference materials, which are needed to prepare the sample and ensure quality assurance and control protocols. In addition, the standard presents a detailed description of sample preparation, contributions factors affecting the uncertainty budget, the general procedure to check instrumental calibration, determining limits of detection and quantification, and methods for spectra fitting. [ABSTRACT FROM AUTHOR]

Microwave-assisted hydro-distillation (MAHD) at different power levels has been applied for the extraction of essential oil from O. vulgare L. ssp. hirtum. Hydrolats and residual extracts, which present by-products, were also collected. A comparison was done with conventional hydro-distillation (HD) in terms of extraction time, extraction yield, the chemical composition of essential oils and environmental impact. MAHD proved to be a technique with many advantages compared to conventional HD. MAHD had shorter extraction time (24-45 min) compared to HD (136 min), better yields of essential oil (2.55-7.10 % for MAHD compared to 5.81 % for HD), higher content of oxygenated compounds (78.89-85.15 % for MAHD compared to 76.82 for HD), and a more environmentally friendly approach (electrical consumption was from 0.135-0.240kWh for MAHD compared to 1.360kWh for HD). The main component in all essential oils, as well as in hydrolats, was carvacrol. MAHD at the power level of 600 W may be considered as the most promising among the tested power levels with respect to all investigated parameters. Residual extracts after HD and MAHD showed to be valuable by-products rich in phenolic compounds, with rosmarinic acid as dominant. [ABSTRACT FROM AUTHOR]

Results presented are part of a larger mixed-mode study on supplier quality practices focusing on the cross-analysis of interviews, focus groups, and a questionnaire, which collected actual data about timing, costs, practices, and non-conformances associated with purchase orders (POs) from Engineering Procure and Construct (EPC) projects for four material types considered relevant to projects built by EPC contractors based in the United States. The present discussion specifically focuses on the analysis of the non-parametric dataset obtained from the POs to investigate a subset of companies labelled as highly effective companies (HECs). This contribution is unique as it used a mixed-mode approach to collect data beyond construction sites and investigate the product/supplier side of construction processes to advance knowledge of how materials can be sent to construction project sites free of defects and rework and indicates practices that contribute to this goal. When compared to other companies in the dataset, HECs engage in more hours of observation in suppliers' facilities, communicate more often with suppliers, put more effort and time in the planning stages of the project, use more practices related to supplier quality surveillance and supplier quality management, and find non-conformances earlier in the project. [ABSTRACT FROM AUTHOR]

Liquid chromatography (LC) based techniques in combination with mass spectrometry (MS) detection have had a large impact on the development of new pharmaceuticals in the past decades. Continuous improvements in mass spectrometry and interface technologies, combined with advanced liquid chromatographic techniques for high-throughput qualitative and quantitative analysis, have resulted in a wider scope of applications in the pharmaceutical field. LC-MS tools are increasingly used to analyze pharmaceuticals across a variety of stages in their discovery and development. These stages include drug discovery, product characterization, metabolism studies (in vitro and in vivo) and the identification of impurities and degradation products. The increase in LC-MS applications has been enormous, with retention times and molecular weights (and related fragmentation patterns) emerging as crucial analytical features in the drug development process. The goal of this review is to give an overview of the main developments in LC-MS based techniques for the analysis of small pharmaceutical molecules in the last decade and give a perspective on future trends in LC-MS in the pharmaceutical field. [ABSTRACT FROM AUTHOR]

In this study, we aim to determine the chemical constituents of six Chinese medicinal materials from the Citrus genus using high‐performance liquid chromatography and high‐resolution mass spectrometry. Eight flavonoids and one coumarin were identified and further quantified as marker substances by high‐performance liquid chromatography method. The separation was performed on an Agilent TC‐C18 column with 0.1% formic acid and acetonitrile as the mobile phase under gradient elution. The analytical method was fully validated in terms of linearity, sensitivity, intra‐ and inter‐day precision and repeatability, limit of detection, limit of quantitation, and recovery. It was subsequently applied to evaluate the quality of 103 batches of the Chinese medicinal materials from the Citrus genus. In addition, the principal constituent analysis was used to compare the samples of different species from the Citrus genus leading to successful classification of the samples in accordance with their origins. It was found that the contents of nine constituents varied greatly in different ripening stages and varieties of the samples from the Citrus genus. In addition, neoeriocitrin and 5,7‐dimethoxycoumarin were determined as two unique constituents of 'Zhiqiao' and 'Foshou', respectively. In conclusion, this study provides a chemical basis for quality control of Chinese medicinal materials from the Citrus genus. [ABSTRACT FROM AUTHOR]

• 51 rear-end conflicts, from a naturalistic driving study in China, were analyzed. • Kinematic and glance behavior variables were extracted from videos of conflicts. • Before conflicts, Chinese drivers directed most of the off-path gazes towards mirrors. • Chinese drivers kept short headways and responded fast when looking back on path. • Differences in driver behavior between China and Western countries were found. Introduction: Rear-end crashes are one of the most frequent crash types in China, leading to significant economic and societal losses. The development of active safety systems – such as Automatic Emergency Braking System (AEBS) – could avoid or mitigate the consequences of these crashes in Chinese traffic situations. However, a clear understanding of the crash causation mechanisms is necessary for the design of these systems. Method: Manually coded variables were extracted from a naturalistic driving study conducted with commercial vehicles in Shanghai. Quantitative analyses of rear-end crashes and near crashes (CNC) were conducted to assess the prevalence, duration, and location of drivers' off-path glances, the influence of lead vehicle brake lights on drivers' last off-path glance, and driver brake onset, and the influence of off-path glances and kinematic criticality on drivers' response to conflicts. Results: The results indicate that the Chinese truck drivers in our study rarely engage in distracting activities involving a phone or other handheld objects while driving. Instead, they direct their off-path glances mainly toward the mirrors, and the duration of off-path glances leading to critical situations are shorter compared to earlier analyses performed in Western countries. The drivers also often keep small margins. Conclusions: Overall, the combination of short time headway with off-path glances directed toward the mirror originates visual mismatches which, associated to a rapid change in the kinematic situation, cause the occurrence of rear-end CNC. When drivers look back toward the road after an off-path glance, a fast response seems to be triggered by lower values of looming compared to previous studies, possibly because of the short time headways. Practical Application: The results have practical implications for the development of driver models, for the design of active safety systems and automated driving, and for the design of campaigns promoting safe driving. [ABSTRACT FROM AUTHOR]

Multiferroic six-layer Aurivillius type Bi7Fe3Ti3O21 ceramics was obtained by conventional mixed oxides method. The final sintering process was taken in several different sintering times, which determined changes in properties of discussed ceramic material. The structure and dielectric properties of the material are reported. In order to examine the technological conditions on the crystal structure, XRD analysis was carried out. The microstructure, as well as the quantitative and qualitative analysis of the chemical composition were investigated by scanning electron microscope with an energy dispersion spectrometer. The main purpose of the paper is to present the effect of sintering time on the microstructure, crystallographic structure and dielectric properties of Bi7Fe3Ti3O21 ceramics. [ABSTRACT FROM AUTHOR]

Texture is the orientation distribution of crystallites in polycrystalline materials. Given the discrete orientations, Schaeben suggested to adopt statistics for quantitative analysis of texture from discrete orientations, and he also conceived a clustering algorithm to facilitate the applications of statistical methods (H. Schaeben, J Appl Crystal 26:112–121, 1993). This data-driven scheme becomes more urgent and more necessary for the oncoming fourth paradigm: data-intensive scientific discovery, which follows after experimental science, theoretical science, and computational science paradigm. This research adopts a density-based clustering algorithm, DBSCAN, to process the orientation data from an austenitic stainless steel 316 L sample fabricated by selective laser melting. It is validated that the algorithm can robustly identify the orientation cluster (or texture component or preferred orientation). The statistical methods can successfully quantify the features of the identified orientation cluster with quantified uncertainty (statistical significance), which is often lacked in the general method of orientation distribution function. It is believed that this data-driven scheme can be applied to the many aspects of texture analysis. [ABSTRACT FROM AUTHOR]

Background: Amphotericin B (AmB) is widely used against fungal infection and produced mainly by Streptomyces nodosus. Various intracellular metabolites of S. nodosus were identified during AmB fermentation, and the key compounds that related to the cell growth and biosynthesis of AmB were analyzed by principal component analysis (PCA) and partial least squares (PLS). Results: Rational design that based on the results of metabolomics was employed to improve the AmB productivity of Streptomyces nodosus, including the overexpression of genes involved in oxygen-taking, precursor-acquiring and product-exporting. The AmB yield of modified strain S. nodosus VMR4A was 6.58 g/L, which was increased significantly in comparison with that of strain S. nodosus ZJB2016050 (5.16 g/L). This was the highest yield of AmB reported so far, and meanwhile, the amount of by-product amphotericin A (AmA) was decreased by 45%. Moreover, the fermentation time of strain S. nodosus VMR4A was shortened by 24 h compared with that of strain. The results indicated that strain S. nodosus VMR4A was an excellent candidate for the industrial production of AmB because of its high production yield, low by-product content and the fast cell growth. Conclusions: This study would lay the foundation for improving the AmB productivity through metabolomics analysis and overexpression of key enzymes. [ABSTRACT FROM AUTHOR]

Access to clean water have great importance for a healthy life. It should not directly or indirectly pose any physical, chemical, microbiological or even radioactive risks in terms of human health and should not cause various diseases/poisonings. Water safety is ensured and kept under control with the results of chemical and microbiological analysis of the samples, which were sampling. With the reliability of these analysis results, access of safe water is provided. Accreditation have great importance in ensuring reliable results in chemical and microbiological analysis services. In our country, accreditation procedures of the water laboratories are carried out with the TS EN ISO/IEC 17025 standard. TS EN ISO/IEC 17025 standard which was renewed on 18.12.2017. With the renewal of the TS EN ISO/IEC 17025 standard, changes in the practices of the services of accredited water laboratories have occurred. In this study, with the renewed TS EN ISO/IEC 17025: 2017 standard, it is aimed to define the requirements of the water laboratories accredited and/or will be accredited, to determine the practices for their activities and to reveal the changes. The basic change with TS EN ISO/IEC 17025: 2017 standard was the clause configuration. In the TS EN ISO/IEC 17025: 2017, one of the most important basic changes is the introduction of risk-based thinking in water laboratories. With this renewed standard, emphasis is placed on impartiality while conducting laboratory activities, and confidentiality. Under this standard, definition of laboratory was comprised of testing, calibration and sampling associated with subsequent testing or calibration. Only an organization, that performs sampling activities can be accredited within the scope of TS EN ISO/IEC 17025: 2017 with this activity. Where a declaration of conformity to requirement, specification or standard is specified in the reports of chemical and microbiological quantitative analysis results; the establishment of the decision rule, which is an indicator of the application of measurement uncertainties of laboratories, has been described. With TS EN ISO/IEC 17025: 2017 revision standard; expressions such as focusing on information technologies, usage of computer systems, production of electronic results, electronic records and reports, and the validity of the software are more frequent, but it has also importance to ensure its security. In addition, by clarifying the terminology with this standard, terms such as verification, validation and metrological traceability have been clarified. [ABSTRACT FROM AUTHOR]

In this study, we propose a method to quantitatively analyze the concentration of VOCs adsorbed on zeolite filters via gas chromatography (GC). The sampled VOCs from the filters with ethanol as a solution were characterized using GC to determine the concentration of the adsorbed VOCs by comparing the areas of GC peaks of the detected VOCs and ethanol. The proposed method also enabled determination of the desorption (regeneration) conditions of the zeolite filters according to heating temperature and time for various VOCs. Repeated adsorption and desorption of VOCs on zeolite filters and GC analyses allow us to evaluate the durability and reusability of the filter and could help predict the lifetime of zeolite filters in practice. [ABSTRACT FROM AUTHOR]

Nano-flow liquid chromatography tandem mass spectrometry (nano-flow LC–MS/MS) is the mainstay in proteome research because of its excellent sensitivity but often comes at the expense of robustness. Here we show that micro-flow LC–MS/MS using a 1 × 150 mm column shows excellent reproducibility of chromatographic retention time (<0.3% coefficient of variation, CV) and protein quantification (<7.5% CV) using data from >2000 samples of human cell lines, tissues and body fluids. Deep proteome analysis identifies >9000 proteins and >120,000 peptides in 16 h and sample multiplexing using tandem mass tags increases throughput to 11 proteomes in 16 h. The system identifies >30,000 phosphopeptides in 12 h and protein-protein or protein-drug interaction experiments can be analyzed in 20 min per sample. We show that the same column can be used to analyze >7500 samples without apparent loss of performance. This study demonstrates that micro-flow LC–MS/MS is suitable for a broad range of proteomic applications. Mass spectrometry-based proteomics typically relies on highly sensitive nano-flow liquid chromatography (LC) but this can reduce robustness and reproducibility. Here, the authors show that micro-flow LC enables robust and reproducible high-throughput proteomics experiments at a very moderate loss of sensitivity. [ABSTRACT FROM AUTHOR]

Many shore crabs exhibit juvenile colour pattern polymorphism on their carapace, which helps avoid predation through camouflage. However, colour pattern polymorphism has been described only in a limited number of species, and its quantitative descriptions are rare. Here, we studied the Asian grapsid crab Hemigrapsus penicillatus to describe its polymorphic dichromatic carapace patterns. We specifically examined how dichromatic patterns and the degree of pattern polymorphism change as size increases and whether sexual/size differences exist in carapace patterns. Our results showed that H. penicillatus exhibits polymorphic forms in both the juvenile and adult stages. Additionally, compared with males, females were more likely to exhibit dichromatic carapace patterns and had a larger light-coloured area on their carapace. Estimation of the likelihood of the carapace being light or dark coloured suggested that certain areas on the carapace are less variable than other areas. We discuss potential adaptive explanations for our results. [ABSTRACT FROM AUTHOR]

The formation of DNA adducts by genotoxic agents is an early event in cancer development, and it may lead to gene mutations, thereby initiating tumor development. The measurement of DNA adducts can provide critical information about the genotoxic potential of a chemical and its mechanism of carcinogenesis. In recent decades, liquid chromatography coupled with mass spectrometry has become the most important technique for analyzing DNA adducts. The improvements in resolution achievable with new chromatographic separation techniques coupled with the high specificity and sensitivity and wide dynamic range of new mass spectrometry systems have been used for both qualitative and quantitative analyses of DNA adducts. This review discusses the challenges in qualitative and quantitative analyses of DNA adducts by liquid chromatography coupled with mass spectrometry and highlights recent developments towards overcoming the limitations of liquid chromatography coupled with mass spectrometry methods. The key steps and new solutions, such as sample preparation, mass spectrometry fragmentation, and method validation, are summarized. In addition, the fundamental principles and latest advances in DNA adductomic approaches are reviewed. [ABSTRACT FROM AUTHOR]

In order to help predict the properties of molten salts electrolytes and aluminium brazing flux used in the Hall–Héroult process and in aluminium brazing, the microstructure of binary KF‐AlF3 system from 298 K to its molten states was explored by in situ high‐temperature Raman spectroscopy in argon atmosphere. Comparing with experimental Raman spectra in molten system, quantum chemistry ab initio simulations were used to calculate the symmetric stretching vibrational modes of probable clusters in the melts. The molten KF‐AlF3 system was found to comprise monomer [AlF6]3−, [AlF5]2−, [AlF4]−, and dimer [Al2F7]− clusters. With the increase of KF content in the melts, the major species changes from [AlF4]− tetrahedra to [AlF6]3− octahedra. From the deconvoluted measured Raman spectra, the mole fractions of varied clusters in the system were also calculated. As the KF:AlF3 ratio was increased from 1 to 3, the content of [AlF6]3− in the melt increased from 22.30 to 98.83 mol%, whereas the [AlF4]− content decreased from 68.92 to 0.33 mol%. [AlF5]2− and [Al2F7]− clusters were also found in small amounts in the melts. [ABSTRACT FROM AUTHOR]

Stopping power (SP) and inelastic mean free path (IMFP) of electrons in Ti, Fe, Ni, and Pd have been determined by using dielectric models. We have used energy loss function (ELF) determined from quantitative analysis of experimental reflection electron energy loss spectroscopy (REELS) spectra as the input parameter for this model. ELF in this study was determined from the previously published quantitative analysis of REELS spectra. The SP of Fe, Ni, Pd, and Ti was compared with several calculation methods for energies from 100 eV to 10 keV and shows SP in this study, which are in best agreement for medium to high energies (greater than or equal to 300 eV). The IMFP obtained in this study shows the best agreement with online database TPP2M and NIST and also calculation by Tanuma with a root mean square (rms) less than 12%. The present approach shows ELF from quantitative analysis of REELS spectra has a high potential for the experimental determination of SP and IMFP of metals. [ABSTRACT FROM AUTHOR]

Aiming at the classic problem of pilling of polyester-cotton blended woven fabrics, pilling grades were evaluated by image analysis method to study the effects of yarn twist, spinning method, warp, and weft density, fabric cover factor and fabric singeing on pilling performance. The length and density distribution of fabric hairiness was studied by Nano measurer software. The respective roles of polyester and cotton fibers were studied by using scanning electron microscope and quantitative chemical analysis method. The experimental results showed that the factors for the best anti-pilling fabric are that yarn twist is 950 N/m, the spinning method is siro-compact spinning, warp density is 394 N/10cm, weft density is 265 N/10cm, fabric cover factor is 103.9%, and fabric should be singed. Cotton hairiness is fractured, which is wrapped by polyester hairiness to form pills. The frequency distribution of hairiness is approximately given by Gauss distribution. Mass ratio of polyester and cotton hairiness is nearly 66%/34%. [ABSTRACT FROM AUTHOR]

This paper presents the implementation of a tool that can be used to characterise chromatic attributes of an urban area. The challenge is to provide statistical and quantitative answers to these questions: how is colour organised, how does it develop its own structure in the city? How can colour appear as an indicator of homogeneity and spatial coherence? We use a K-means statistical clustering technique to produce chromatic types of building façades. Once the chromatic categories are defined, the question of spatial coherence is investigated using the Shannon entropy value as an indicator. Our method was tested through an application to 18 urban fragments of the city of Liège (Belgium). The research highlights the differences between compact urban areas (historic centre, nineteenth century developments) and new urban configurations (city entrances, commercial and peri-urban zones). [ABSTRACT FROM AUTHOR]

The non-equilibrium structural and dynamical properties of semiflexible polymers confined to two dimensions are investigated by molecular dynamics simulations. Three different scenarios are considered: the force-extension relation of tethered polymers, the relaxation of an initially stretched semiflexible polymer, and semiflexible polymers under shear flow. We find quantitative agreement with theoretical predictions for the force-extension relation and the time dependence of the entropically contracting polymer. The semiflexible polymers under shear flow exhibit significant conformational changes at large shear rates, where less stiff polymers are extended by the flow, whereas rather stiff polymers are contracted. In addition, the polymers are aligned by the flow, thereby the two-dimensional semiflexible polymers behave similarly to flexible polymers in three dimensions. The tumbling times display a power-law dependence at high shear rate rates with an exponent comparable to the one of flexible polymers in three-dimensional systems. [ABSTRACT FROM AUTHOR]

To model intermolecular excitation transfer between organic chromophores in the framework of Förster theory, the interaction matrix element is needed for all relative orientations and separations of chromophores. Simulations of extended multi-chromophoric systems thus require a fast but reliable approximation scheme to calculate these dipole interactions. By means of a comparative study of the dipole approximation with quantum chemistry, we demonstrate that the usual line-dipole theory, while suitable for short molecules, breaks down for longer molecules with inter-molecular separations similar to or smaller than the length of the interacting chromophores; a limit that is typically found in conjugated polymer thin films. As a remedy, we propose an improved way of distributing the sub-dipole moments within a line which provides results in very good agreement with the quantum chemistry, and is still simple enough to be used in large scale simulations. [ABSTRACT FROM AUTHOR]

Measurements of diffusion and driven motion by probe particles in polymer solutions constrain theoretical models of polymer solution dynamics. In this paper, motions of large, intermediate (smaller than a polymer chain, larger than a solvent molecule), and small (solvent, ion) probes through polymer solutions and viscous small-molecule solvents are analyzed. The resulting constraints limit the physical models that can plausibly be used to describe polymer motion and separately limit the mathematical structures that might be used to obtain quantitative predictions from those models. A transition in small-molecule mobility through polymer solutions, at polymer concentrations near 400 g/l, is explained in terms of the size of a solvent molecule relative to the gaps between pairs of chain segments on adjacent polymer molecules. [ABSTRACT FROM AUTHOR]

Nuclear magnetic shieldings of both carbon and hydrogen atoms of haluro methyl molecules are highly influenced by the substitution of one or more hydrogen by halogen heavy atoms. We applied the linear response elimination of small components, LRESC, formalism to calculate such shieldings and learn whether including only few terms is enough for getting quantitative reproduction of the total shieldings or not. First, we discuss the contribution of all leading relativistic corrections to σ(C), in CHX2I molecular models with X = H, F, and Cl, and show that spin-orbit (SO) effects are the main ones. After adding the SO effects to the non-relativistic (NR) results, we obtain ∼ 97% (93%) of the total LRESC values for σ(C) (σ(H)). The magnitude of SO terms increases when the halogen atom becomes heavier. In this case, such contributions to σ(C) can be extrapolated as a function of Z, the halogen atomic number. Furthermore, when paramagnetic spin-orbit (PSO) contributions are also considered, we obtain results that are within 1% of the total LRESC value. Then we study in detail the main electronic mechanisms involved to contribute C and H shieldings on CHnX4 - n (n = 1, 3), and CHXYZ (X, Y, Z = F, Cl, Br, I) model compounds. The pattern of σ(C) for all series of compounds follows a normal halogen dependence (NHD), though with different rate of increase. A special family of compounds is that of CHF2X for which σnr(C) follows an inverse halogen dependence though the total shielding have a NHD due to the SO contributions. For the series CH3X (X = F, Cl, Br and I), we found that σSO ∼ ZX2.53. Another important finding of this work is the logarithmic dependence of σSO(C) with the substituent atomic number: ln σSO(C) = AX + aX ZY for both family of compounds CH2XY and CHX2Y. We also performed four-component calculations using the spin-free Hamiltonian to obtain SO contributions within a four-component framework. [ABSTRACT FROM AUTHOR]

Quantitative Fourier-transform infrared spectra for low-temperature (160-200 K) aerosols of clathrate-hydrate nanoparticles that contain large-cage catalysts and small-cage nonpolar guests have been extended to a broad range of vapor compositions and sampling conditions. The data better reveal the stages by which room-temperature vapor mixtures, when cooled below ∼220 K, instantly generate aerosols with particles composed exclusively of the corresponding clathrate hydrates. In particular the quantitative data help relate the nature of the hydrates that form to the composition of the aqueous nanodroplets of the first stages of the rapid transition from the all-vapor mixture. The overall transition from an all-vapor mixture to 'gas'-hydrate nanocrystals is a multistage one that has been characterized as homogeneous nucleation and growth of solution nanodroplets (∼240 K) followed by nucleation and growth of the gas-hydrate particles (∼220 K); all occurring within a subsecond that follows pulsing of the warm vapor into a sampling cold chamber. This may serve well as a general description of the instantaneous generation of the gas-hydrate aerosols, but closer consideration of the nature of the sampling method, in context with recent computation-based insights to (a) gas-hydrate nucleation stages/rates and (b) the lifetimes of trapped small nonpolar molecules in cold aqueous nanodroplets, suggests a more complex multistage transition. The simulated lifetimes and extensive new quantitative infrared data significantly broaden the knowledge base in which the instantaneous transition from vapor to crystalline hydrate particles is viewed. The apparent need for a high occupancy of large-cage catalytic guest molecules currently limits the practical value of the all-vapor method. Only through greater clarity in the molecular-level description of the transition will the ultimate limits be defined. [ABSTRACT FROM AUTHOR]

As a physical model of the surface of cells coated with densely packed, non-crystalline proteins coupled to lipid anchors, we functionalized the surface of phospholipid membranes by coupling of neutravidin to biotinylated lipid anchors. After the characterization of fine structures perpendicular to the plane of membrane using specular X-ray reflectivity, the same membrane was characterized by grazing incidence small angle X-ray scattering (GISAXS). Within the framework of distorted wave Born approximation and two-dimensional Percus-Yevick function, we can analyze the form and structure factors of the non-crystalline, membrane-anchored proteins for the first time. As a new experimental technique to quantify the surface density of proteins on the membrane surface, we utilized grazing incidence X-ray fluorescence (GIXF). Here, the mean intermolecular distance between proteins from the sulfur peak intensities can be calculated by applying Abelé's matrix formalism. The characteristic correlation distance between non-crystalline neutravidin obtained by the GISAXS analysis agrees well with the intermolecular distance calculated by GIXF, suggesting a large potential of the combination of GISAXS and GIXF in probing the lateral density and correlation of non-crystalline proteins displayed on the membrane surface. [ABSTRACT FROM AUTHOR]

A quantitative theory of hydrodynamic interactions in unentangled polymer melts and concentrated solutions is presented. The study is focussed on the pre-Rouse transient time regimes (t < τR, the Rouse relaxation time) where the hydrodynamic response is governed mainly by the viscoelastic effects. It is shown that transient viscoelastic hydrodynamic interactions are not suppressed (screened) at large distances and are virtually independent of polymer molecular mass. A number of transient regimes of unusual and qualitatively different behavior of isotropic and anisotropic hydrodynamic response functions are elucidated. The regimes are characterized in terms of two main length-scale dependent characteristic times: momentum spreading time τi ∝ r4/3 and viscoelastic time τ* ∝ r4. It is shown that for t > τi the viscoelastic hydrodynamic interactions can be described in terms of the time or length scale dependent effective viscosity which, for t < τR and/or for r < Rcoil, turns out to be much lower than the macroscopic 'polymer' viscosity ηm. The theory also involves a quantitative analysis of the length-scale dependent stress relaxation in polymer melts. The general predictions for hydrodynamic interactions in thermostated systems with Langevin friction are obtained as well. [ABSTRACT FROM AUTHOR]

We introduce a compact finite-temperature density functional model to study electron self-trapping in both liquid and vapor 3He and 4He. This model can quantitatively reproduce the most essential thermodynamic properties of 3He and 4He along their liquid-vapor coexistence lines. The structures and energetics of self-trapped electron bubbles on the 1S ground state and 1P excited state are particularly investigated. Our results show that 1S and 1P bubbles exist in liquid at any temperature, whereas 1S bubbles exist in vapor only above 1.6 K in 3He and above 2.8 K in 4He, 1P bubbles exist in vapor only above 2.5 K in 3He and 4.0 K in 4He. An initially spherical 1P bubble is unstable against deformation towards a peanut shape. In liquid, a peanut-shaped 1P bubble is held from fission by surface tension until reaching the liquid-vapor critical point, whereas in vapor it always splits into two smaller bubbles. The existence of 1P bubbles in finite-temperature liquid helium and their fission instability in helium vapor reveal interesting physics in this system. [ABSTRACT FROM AUTHOR]

Force-extension curves (FECs), which quantify the response of a variety of biomolecules subject to mechanical force (f), are often quantitatively fit using worm-like chain (WLC) or freely jointed chain (FJC) models. These models predict that the chain extension, x, normalized by the contour length increases linearly at small f and at high forces scale as x ∼ (1 - f-α), where α = 0.5 for WLC and unity for FJC. In contrast, experiments on single-stranded DNA (ssDNA) show that over a range of f and ionic concentration, x scales as x ∼ ln f, which cannot be explained using WLC or FJC models. Using theory and simulations we show that this unusual behavior in FEC in ssDNA is due to sequence-independent polyelectrolyte effects. We show that the x ∼ ln f arises because in the absence of force the tangent correlation function, quantifying chain persistence, decays algebraically on length scales on the order of the Debye length. Our theory, which is most appropriate for monovalent salts, quantitatively fits the experimental data and further predicts that such a regime is not discernible in double-stranded DNA. [ABSTRACT FROM AUTHOR]

Drift velocity and driving force are not directly proportional in the case of inhomogeneous suspensions, where a space dependent mobility induces an additional contribution to the drift velocity. Similarly, particle flux and drift velocity are related not only by the gradient of density but also by an additional contribution given by the gradient of the self-diffusion coefficient. We provide quantitative support to this scenario in a non-equilibrium system by means of computer simulations with a temperature gradient. Moreover, our simulation results demonstrate that the temperature gradient-induced mass transport coefficient, namely thermal diffusion coefficient, is not directly proportional to the drift velocity so that the well-accepted relation of proportionality is just an approximation. [ABSTRACT FROM AUTHOR]

We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles. Our results shed light on whether commonly used models of the bath calculated via detailed electronic structure calculations can reproduce the key dynamics. For the systems we model, the time scales of coherent transport are experimentally known from time-dependent polarization anisotropy measurements, and so we can directly assess whether current techniques are predictive for modeling coherent transport. The coupling of the electronic degrees of freedom to the nuclear degrees of freedom is calculated from first-principles rather than assumed, and the fluorescence anisotropy decay is directly reproduced. Surprisingly, we find that although time-dependent density functional theory absolute energies are routinely in error by orders of magnitude more than the coupling energy between monomers, the coherent transport properties of these dimers can be semi-quantitatively reproduced from these calculations. Future directions which must be pursued to yield predictive and reliable models of coherent transport are suggested. [ABSTRACT FROM AUTHOR]

Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies. [ABSTRACT FROM AUTHOR]

In the present work, the effect of Dy3+ substitution on the structural and magnetic properties of CoFe2-xDyxO4 (x = 0.00 to 0.1 in step of 0.025) system synthesized by solution combustion method were investigated. The thermal decomposition process was investigated by means of differential and thermal gravimetric analysis that showed that the precursor could yield the final product after calcination above 600 °C. The phase purity and crystal lattice symmetry were estimated from X-ray diffraction studies. The microstructural features were observed by scanning electron microscopy that demonstrates the fine clustered particles with an increase of average grain size with Dy3+ content. The existence of constituent's, i.e., Co, Fe, and Dy were authenticated by energy dispersive X-ray analysis. An infrared spectroscopy study shows the presence of two absorption bands in the frequency range around 590 cm-1 (ν1) and around 480 cm-1 (ν2); which indicate the presence of tetrahedral and octahedral group complexes, respectively, within the spinel lattice. Room temperature magnetization measurements showed that the saturation magnetization and hysteresis losses (coercivity) decreases with Dy3+ addition, which implies that these materials may be applicable for magnetic data storage and recording media. [ABSTRACT FROM AUTHOR]