共找到 20 条结果
Methanolic extracts of 13 commercially available citrus spp., peels and tissues growing in Iran were investigated for their antioxidant activity by DPPH method. IC50 for antioxidant activity ranged from 0.6-3.8 mg ml(-1). Total phenolic content of the citrus spp. samples (based on folin Ciocalteu method) varied from 66.5 to 396.8 mg gallic acid equivalent/g of extract and flavonoids content (based on colorimetric AlCl3 method) varied from 0.3 to 31.1 mg quercetin equivalent/g of extract. There were no correlation between the total phenolic and/or flavonoids contents and antioxidant activity in tissues and/or peels.
BACKGROUND: The aim of this study was to screen various solvent extracts of whole plant of Torilis leptophylla to display potent antioxidant activity in vitro and in vivo, total phenolic and flavonoid contents in order to find possible sources for future novel antioxidants in food and pharmaceutical formulations. MATERIAL AND METHODS: A detailed study was performed on the antioxidant activity of the methanol extract of whole plant of Torilis leptophylla (TLM) and its derived fractions {n-hexane (TLH), chloroform (TLC) ethyl acetate (TLE) n-butanol (TLB) and residual aqueous fraction (TLA)} by in vitro chemical analyses and carbon tetrachloride (CCl4) induced hepatic injuries (lipid peroxidation and glutathione contents) in male Sprague-Dawley rat. The total yield, total phenolic (TPC) and total flavonoid contents (TFC) of all the fractions were also determined. TLM was also subjected to preliminary phytochemical screening test for various constituents. RESULTS: The total phenolic contents (TPC) (121.9±3.1 mg GAE/g extract) of TLM while total flavonoid contents (TFC) of TLE (60.9 ±2.2 mg RTE/g extract) were found significantly higher as compared to other solvent fractions. Phytochemical screening of TLM revealed the presence of alkaloids, anthraquinones, cardiac glycosides, coumarins, flavonoids, saponins, phlobatannins, tannins and terpenoids. The EC50 values based on the DPPH (41.0±1 μg/ml), ABTS (10.0±0.9 μg/ml) and phosphomolybdate (10.7±2 μg/ml) for TLB, hydroxyl radicals (8.0±1 μg/ml) for TLC, superoxide radicals (57.0±0.3 μg/ml) for TLM and hydrogen peroxide radicals (68.0±2 μg/ml) for TLE were generally lower showing potential antioxidant properties. A significant but marginal positive correlation was found between TPC and EC50 values for DPPH, hydroxyl, phosphomolybdate and ABTS, whereas another weak and positive correlation was determined between TFC and EC50 values for superoxide anion and hydroxyl radicals. Results of in vivo experiment revealed that administration of CCl4 caused a significant increase in lipid peroxidation (TBARS) while decrease in GSH contents of liver. In contrast, TLM (200 mg/kg bw) and silymarin (50 mg/kg bw) co-treatment effectively prevented these alterations and maintained the antioxidant status. CONCLUSION: Data from present results revealed that Torilis leptophylla act as an antioxidant agent due to its free radical scavenging and cytoprotective activity.
The contents of free and total phenolic acids and alk(en)ylresorcinols were analyzed in commercial products of eight grains: oat (Avena sativa), wheat (Triticum spp.), rye (Secale cerale), barley (Hordeum vulgare), buckwheat (Fagopyrum esculentum), millet (Panicum miliaceum), rice (Oryza sativa), and corn (Zea mays). Avenanthramides were determined in three oat products. Free phenolic acids, alk(en)ylresorcinols, and avenanthramides were extracted with methanolic acetic acid, 100% methanol, and 80% methanol, respectively, and quantified by HPLC. The contents of total phenolic acids were quantified by HPLC analysis after alkaline and acid hydrolyses. The highest contents of total phenolic acids were in brans of wheat (4527 mg/kg) and rye (4190 mg/kg) and in whole-grain flours of these grains (1342 and 1366 mg/kg, respectively). In other products, the contents varied from 111 mg/kg (white wheat bread) to 765 mg/kg (whole-grain rye bread). Common phenolic acids found in the grain products were ferulic acid (most abundant), ferulic acid dehydrodimers, sinapic acid, and p-coumaric acid. The grain products were found to contain either none or only low amounts of free phenolic acids. The content of avenanthramides in oat flakes (26-27 mg/kg) was about double that found in oat bran (13 mg/kg). The highest contents of alk(en)ylresorcinols were observed in brans of rye (4108 mg/kg) and wheat (3225 mg/kg). In addition, whole-grain rye products (rye bread, rye flour, and whole-wheat flour) contained considerable levels of alk(en)ylresorcinols (524, 927, and 759 mg/kg, respectively).
The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.
OBJECTIVE: To determine if the semirecumbent position (45-degree angle) decreases aspiration of gastric contents to the airways in intubated and mechanically ventilated patients. DESIGN: A randomized, two-period crossover trial. SETTING: Respiratory intensive care unit. PATIENTS: Nineteen patients requiring intubation and mechanical ventilation. INTERVENTIONS: Patients were studied in the supine and semirecumbent positions on two separate days. MEASUREMENTS: After technetium (Tc)-99m sulphur colloid labeling of gastric contents, sequential radioactive counts in endobronchial secretions were measured at 30-minute intervals over a 5-hour period. Samples of endobronchial secretions, gastric juice, and pharyngeal contents were obtained for qualitative bacterial cultures. RESULTS: Mean radioactive counts in endobronchial secretions were higher in samples obtained while patients were in the supine position than in those obtained while patients were in the semirecumbent position (4154 cpm compared with 954 cpm; P = 0.036). Moreover, the aspiration pattern was time-dependent for each position: For the supine position, radioactivity was 298 cpm at 30 min and 2592 cpm at 300 min (P = 0.013); for the semirecumbent position, radioactivity was 103 cpm at 30 min and 216 cpm at 300 min (P = 0.04). The same microorganisms were isolated from stomach, pharynx, and endobronchial samples in 32% of studies done while patients were semirecumbent and in 68% of studies done while patients were in the supine position. CONCLUSIONS: We conclude that the supine position and length of time the patient is kept in this position are potential risk factors for aspiration of gastric contents. Elevating the head of the bed for patients who can tolerate the semirecumbent position may be a simple, no-cost prophylactic measure.
Methods for analysing fish stomach contents are listed and critically assessed with a view to their suitability for determining dietary importance—this term is defined. Difficulties in the application of these methods are discussed and, where appropriate, alternative approaches proposed. Modifications which have practical value are also considered. The necessity of linking measurements of dietary importance to stomach capacity is emphasized and the effects of differential digestion upon interpretation of stomach contents outlined. The best measure of dietary importance is proposed as one where both the amount and bulk of a food category are recorded.
INTRODUCTION: The PCR-based analysis of homologous genes has become one of the most powerful approaches for species detection and identification, particularly with the recent availability of Next Generation Sequencing platforms (NGS) making it possible to identify species composition from a broad range of environmental samples. Identifying species from these samples relies on the ability to match sequences with reference barcodes for taxonomic identification. Unfortunately, most studies of environmental samples have targeted ribosomal markers, despite the fact that the mitochondrial Cytochrome c Oxidase subunit I gene (COI) is by far the most widely available sequence region in public reference libraries. This is largely because the available versatile ("universal") COI primers target the 658 barcoding region, whose size is considered too large for many NGS applications. Moreover, traditional barcoding primers are known to be poorly conserved across some taxonomic groups. RESULTS: We first design a new PCR primer within the highly variable mitochondrial COI region, the "mlCOIintF" primer. We then show that this newly designed forward primer combined with the "jgHCO2198" reverse primer to target a 313 bp fragment performs well across metazoan diversity, with higher success rates than versatile primer sets traditionally used for DNA barcoding (i.e. LCO1490/HCO2198). Finally, we demonstrate how the shorter COI fragment coupled with an efficient bioinformatics pipeline can be used to characterize species diversity from environmental samples by pyrosequencing. We examine the gut contents of three species of planktivorous and benthivorous coral reef fish (family: Apogonidae and Holocentridae). After the removal of dubious COI sequences, we obtained a total of 334 prey Operational Taxonomic Units (OTUs) belonging to 14 phyla from 16 fish guts. Of these, 52.5% matched a reference barcode (>98% sequence similarity) and an additional 32% could be assigned to a higher taxonomic level using Bayesian assignment. CONCLUSIONS: The molecular analysis of gut contents targeting the 313 COI fragment using the newly designed mlCOIintF primer in combination with the jgHCO2198 primer offers enormous promise for metazoan metabarcoding studies. We believe that this primer set will be a valuable asset for a range of applications from large-scale biodiversity assessments to food web studies.
The rapid growth of the Web in the last decade makes it the largest publicly accessible data source in the world.Web mining aims to discover useful information or knowledge from Web hyperlinks, page contents, and usage logs.Based on the primary kinds of data used in the mining process, Web mining tasks can be categorized into three main types: Web structure mining, Web content mining and Web usage mining.Web structure mining discovers knowledge from hyperlinks, which represent the structure of the Web.Web content mining extracts useful information/knowledge from Web page contents.Web usage mining mines user access patterns from usage logs, which record clicks made by every user.The goal of this book is to present these tasks, and their core mining algorithms.The book is intended to be a text with a comprehensive coverage, and yet, for each topic, sufficient details are given so that readers can gain a reasonably complete knowledge of its algorithms or techniques without referring to any external materials.Four of the chapters, structured data extraction, information integration, opinion mining, and Web usage mining, make this book unique.These topics are not covered by existing books, but yet they are essential to Web data mining.Traditional Web mining topics such as search, crawling and resource discovery, and link analysis are also covered in detail in this book.Although the book is entitled Web Data Mining, it also includes the main topics of data mining and information retrieval since Web mining uses their algorithms and techniques extensively.The data mining part mainly consists of chapters on association rules and sequential patterns, supervised learning (or classification), and unsupervised learning (or clustering), which are the three most important data mining tasks.The advanced topic of partially (semi-) supervised learning is included as well.For information retrieval, its core topics that are crucial to Web mining are described.This book is thus naturally divided into two parts.The first part, which consists of Chaps.2-5, covers data mining foundations.The second part, which contains Chaps.6-12, covers Web specific mining.Two main principles have guided the writing of this book.First, the basic content of the book should be accessible to undergraduate students, and yet there are sufficient in-depth materials for graduate students who plan to Many other researchers also assisted in various ways.Yang Dai and Rudy Setiono helped with Support Vector Machines (SVM).Chris Ding helped with link analysis.
The authors investigated the structure of goal contents in a group of 1,854 undergraduates from 15 cultures around the world. Results suggested that the 11 types of goals the authors assessed were consistently organized in a circumplex fashion across the 15 cultures. The circumplex was well described by positioning 2 primary dimensions underlying the goals: intrinsic (e.g., self-acceptance, affiliation) versus extrinsic (e.g., financial success, image) and self-transcendent (e.g., spirituality) versus physical (e.g., hedonism). The circumplex model of goal contents was also quite similar in both wealthier and poorer nations, although there were some slight cross-cultural variations. The relevance of these results for several theories of motivation and personality are discussed.
Cells communicate with each other through secreting and releasing proteins and vesicles. Many cells can migrate. In this study, we report the discovery of migracytosis, a cell migration-dependent mechanism for releasing cellular contents, and migrasomes, the vesicular structures that mediate migracytosis. As migrating cells move, they leave long tubular strands, called retraction fibers, behind them. Large vesicles, which contain numerous smaller vesicles, grow on the tips and intersections of retraction fibers. These fibers, which connect the vesicles with the main cell body, eventually break, and the vesicles are released into the extracellular space or directly taken up by surrounding cells. Since the formation of these vesicles is migration-dependent, we named them "migrasomes". We also found that cytosolic contents can be transported into migrasomes and released from the cell through migrasomes. We named this migration-dependent release mechanism "migracytosis".
In order to better estimate bacterial biomass in marine environments, we developed a novel technique for direct measurement of carbon and nitrogen contents of natural bacterial assemblages. Bacterial cells were separated from phytoplankton and detritus with glass fiber and membrane filters (pore size, 0.8 &mgr;m) and then concentrated by tangential flow filtration. The concentrate was used for the determination of amounts of organic carbon and nitrogen by a high-temperature catalytic oxidation method, and after it was stained with 4',6-diamidino-2-phenylindole, cell abundance was determined by epifluorescence microscopy. We found that the average contents of carbon and nitrogen for oceanic bacterial assemblages were 12.4 +/- 6.3 and 2.1 +/- 1.1 fg cell-1 (mean +/- standard deviation; n = 6), respectively. Corresponding values for coastal bacterial assemblages were 30.2 +/- 12.3 fg of C cell-1 and 5.8 +/- 1.5 fg of N cell-1 (n = 5), significantly higher than those for oceanic bacteria (two-tailed Student's t test; P < 0.03). There was no significant difference (P > 0.2) in the bacterial C:N ratio (atom atom-1) between oceanic (6.8 +/- 1.2) and coastal (5.9 +/- 1.1) assemblages. Our estimates support the previous proposition that bacteria contribute substantially to total biomass in marine environments, but they also suggest that the use of a single conversion factor for diverse marine environments can lead to large errors in assessing the role of bacteria in food webs and biogeochemical cycles. The use of a factor, 20 fg of C cell-1, which has been widely adopted in recent studies may result in the overestimation (by as much as 330%) of bacterial biomass in open oceans and in the underestimation (by as much as 40%) of bacterial biomass in coastal environments.
This study was designed to assess the effects of irrelevant emotional material on the ability to update the contents of working memory in depression. For each trial, participants were required to memorize 2 lists of emotional words and subsequently to ignore 1 of the lists. The impact of irrelevant emotional material on the ability to update the contents of working memory was indexed by response latencies on a recognition task in which the participants decided whether or not a probe was a member of the relevant list. The authors compared response latencies to probes from the irrelevant list to response latencies to novel probes of the same valence (intrusion effect). The results indicate that, compared to control participants in both neutral and sad mood states, depressed participants showed greater intrusion effects when presented with negative words. In an important finding, intrusion effects for negative words were correlated with self-reported rumination. These findings indicate that depression is associated with difficulties removing irrelevant negative material from working memory. Results also indicate that the increased interference from irrelevant negative material is associated with rumination.
暂无摘要(点击查看原文获取完整内容)
This article presents a four-category framework to characterize the contents of prescriptive gender stereotypes. The framework distinguishes between prescriptions and proscriptions that are intensified by virtue of one's gender, and those that are relaxed by virtue of one's gender. Two studies examined the utility of this framework for characterizing prescriptive gender stereotypes in American society (Study 1) and in the highly masculine context of Princeton University (Study 2). The results demonstrated the persistence of traditional gender prescriptions in both contexts, but also revealed distinct areas of societal vigilance and leeway for each gender. In addition, they showed that women are seen more positively, relative to societal standards, than are men. We consider the implications of this framework for research on reactions to gender stereotype deviants and sex discrimination.
This article presents a theory of potentially universal aspects in the content of human values. Ten types of values are distinguished by their motivational goals. The theory also postulates a structure of relations among the value types, based on the conflicts and compatibilities experienced when pursuing them. This structure permits one to relate systems of value priorities, as an integrated whole, to other variables. A new values instrument, based on the theory and suitable for cross‐cultural research, is described. Evidence relevant for assessing the theory, from 97 samples in 44 countries, is summarized. Relations of this approach to Rokeach's work on values and to other theories and research on value dimensions are discussed. Application of the approach to social issues is exemplified in the domains of politics and intergroup relations.
In present study, we carried out a systematic record of the relative antioxidant activity in selected Iranian medicinal plant species' extracts. The total phenol varied from 24.1 ± 1 to 289.5 ± 5 mg g -1 in the extracts. Flavonoid contents were between 25.15 ± 0.8 and 78.3 ± 4.5 mg g-1. 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect of the extracts was determined spectrophotometrically. The highest radical scavenging effect was observed in Mellilotus officinalis with IC50 = 0.018 mg ml –1. The potency of radical scavenging effect of M. officinalis extract was about 4 times greater than synthetic antioxidant butylated hydroxy toluene (BHT). The greater amount of phenolic compounds leads to morepotent radical scavenging effect as shown by M. officinalis extract
The assertion that both the content of goals and the motives behind goals affect psychological well-being has been controversial. Three studies examined this issue directly, showing that both what goals people pursue (i.e., whether they strive for extrinsic vs. intrinsic goal contents) and why people pursue them (i.e., whether they strive for autonomous vs. controlled motives) make significant independent contributions to psychological well-being. The pattern emerged in between-person and within-person studies of cross-sectional well-being and also emerged in a year-long study of prospective change in well-being. Implications for prescriptive theories of happiness are discussed.
A modification of the graphical Costello method is proposed for the analysis of stomach contents data. The new method allows prey importance, feeding strategy and the interand intra‐individual components of niche width to be explored using graphical presentation. The analysis is based on a two‐dimensional representation of prey‐specific abundance and frequency of occurrence of the different prey types in the diet. The paper describes the new method and the parameters therein, and also present some examples of the utilization of the method. The method may be particularly well‐suited for the examination of predictions made from optimal foraging, competition and niche theories.
Leaf pigment content and composition provide important information about plant physiological status. Reflectance measurements offer a rapid, nondestructive technique to estimate pigment content. This paper describes a recently developed three‐band conceptual model capable of remotely estimating total of chlorophylls, carotenoids and anthocyanins contents in leaves from many tree and crop species. We tuned the spectral regions used in the model in accord with pigment of interest and the optical characteristics of the leaves studied, and showed that the developed technique allowed accurate estimation of total chlorophylls, carotenoids and anthocyanins, explaining more than 91%, 70% and 93% of pigment variation, respectively. This new technique shows a great potential for noninvasive tracking of the physiological status of vegetation and the impact of environmental changes.
<i>Context.<i/> We present the early installment of the third <i>Gaia<i/> data release, <i>Gaia<i/> EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from <i>Gaia<i/> DR2.<i>Aims.<i/> A summary of the contents of <i>Gaia<i/> EDR3 is presented, accompanied by a discussion on the differences with respect to <i>Gaia<i/> DR2 and an overview of the main limitations which are present in the survey. Recommendations are made on the responsible use of <i>Gaia<i/> EDR3 results.<i>Methods.<i/> The raw data collected with the <i>Gaia<i/> instruments during the first 34 months of the mission have been processed by the <i>Gaia<i/> Data Processing and Analysis Consortium and turned into this early third data release, which represents a major advance with respect to <i>Gaia<i/> DR2 in terms of astrometric and photometric precision, accuracy, and homogeneity. <i>Results. Gaia<i/> EDR3 contains celestial positions and the apparent brightness in <i>G<i/> for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (<i>G<i/><sub>BP<sub/> − <i>G<i/><sub>RP<sub/>) colour are also available. The passbands for <i>G<i/>, <i>G<i/><sub>BP<sub/>, and <i>G<i/><sub>RP<sub/> are provided as part of the release. For ease of use, the 7 million radial velocities from <i>Gaia<i/> DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of <i>Gaia<i/> DR3. Finally, <i>Gaia<i/> EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the <i>Gaia<i/>-CRF3, which is based solely on extragalactic sources. The creation of the source list for <i>Gaia<i/> EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for <i>Gaia<i/> DR2, but it does feature new sources and there are some notable changes. The source list will not change for <i>Gaia<i/> DR3.<i>Conclusions. Gaia<i/> EDR3 represents a significant advance over <i>Gaia<i/> DR2, with parallax precisions increased by 30 per cent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30–40% for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for <i>G<i/>, <i>G<i/><sub>BP<sub/>, and <i>G<i/><sub>RP<sub/> is valid over the entire magnitude and colour range, with no systematics above the 1% level