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排序方式: 共有1249条查询结果,搜索用时 125 毫秒
941.
Palacios Natalia; Guttmannova Katarina; Chase-Lansdale P. Lindsay 《Canadian Metallurgical Quarterly》2008,44(5):1381
This article examines whether longitudinal reading trajectories vary by the generational status of immigrant children as they begin formal schooling through the 3rd grade. The results of the hierarchical linear model indicated that 1st and 2nd generation children (i.e., those born in a foreign country and those born in the United States to foreign-born parents, respectively) had higher achievement scores at the spring of kindergarten than did 3rd generation children. Yet, controlling for race/ethnicity and maternal education fully reduced the 1st generation advantage. In addition, 1st generation children grew in reading achievement at a faster rate than did 3rd generation children. Controlling for a host of proximal and distal factors that included demographic, race/ethnic, family, and school characteristics somewhat reduced the association between generational status and rate of growth. First and 2nd generation children continued to increase their reading scores at a faster rate than did 3rd generation children. It is likely that additional factors not measured in the Early Childhood Longitudinal Survey-Kindergarten cohort, such as selection, cultural, or motivational factors, would be useful in further explaining the immigrant advantage. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
942.
The present study reveals the utility of high-performance thin-layer chromatographic (HPTLC) fingerprinting of phenolic constituents for the authentication of monofloral honeys. The obtained data enables a more complete assessment of honey quality and the identification of emerging threats to honey quality. The developed procedure facilitates differentiation of varietal honeys and detection of honey adulterations. We used an HPTLC fingerprint analysis to determine the characteristic patterns of different honey types (willow, buckwheat, heather, pine honeydew, and manuka honey). The HPTLC chromatograms were used to determine the differences in the botanical origin of the honey samples on the basis of the band profiles, which are characteristic for each honey type. Identification of 11 polyphenols was performed by comparison of the color and Rf of the bands with available standards. Additionally, the results were confirmed by an HPLC analysis. 相似文献
943.
Andreja Rajkovic Jelena Jovanovic Silvia Monteiro Marlies Decleer Mirjana Andjelkovic Astrid Foubert Natalia Beloglazova Varvara Tsilla Benedikt Sas Annemieke Madder Sarah De Saeger Mieke Uyttendaele 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1605-1657
Bacterial toxins are food safety hazards causing about 10% of all reported foodborne outbreaks in Europe. Pertinent to Gram‐positive pathogens, the most relevant toxins are emetic toxin and diarrheal enterotoxins of Bacillus cereus, neurotoxins of Clostridium botulinum, enterotoxin of Clostridium perfringens, and a family of enterotoxins produced by Staphylococcus aureus and some other staphylococci. These toxins are the most important virulence factors of respective foodborne pathogens and a primary cause of the related foodborne diseases. They are proteins or peptides that differ from each other in their size, structure, toxicity, toxicological end points, solubility, and stability, types of food matrix to which they are mostly related to. These differences influence the characteristics of required detection methods. Therefore, detection of these toxins in food samples, or detection of toxin production capacity in the bacterial isolate, remains one of the cornerstones of microbial food analysis and an essential tool in understanding the relevant properties of these toxins. Advanced research has led into new insights of the incidence of toxins, mechanisms of their production, their physicochemical properties, and their toxicological mode of action and dose‐response profile. This review focuses on biological, immunological, mass spectrometry, and molecular assays as the most commonly used detection and quantification methods for toxins of B. cereus, C. botulinum, C. perfringens, and S. aureus. Gathered and analyzed information provides a comprehensive blueprint of the existing knowledge on the principles of these assays, their application in food safety, limits of detection and quantification, matrices in which they are applicable, and type of information they provide to the user. 相似文献
944.
Natalia Palacios‐Rojas Laura McCulley Mikayla Kaeppler Tyler J. Titcomb Nilupa S. Gunaratna Santiago Lopez‐Ridaura Sherry A. Tanumihardjo 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1809-1834
Agro‐food systems are undergoing rapid innovation in the world and the system's continuum is promoted at different scales with one of the main outcomes to improve nutrition of consumers. Consumer knowledge through educational outreach is important to food and nutrition security and consumer demands guide breeding efforts. Maize is an important part of food systems. It is a staple food and together with rice and wheat, they provide 60% of the world's caloric intake. In addition to being a major contributor to global food and nutrition security, maize forms an important part of the culinary culture in many areas of Africa, the Americas, and Asia. Maize genetics are being exploited to improve human nutrition with the ultimate outcome of improving overall health. By impacting the health of maize consumers, market opportunities will be opened for maize producers with unique genotypes. Although maize is a great source of macronutrients, it is also a source of many micronutrients and phytochemicals purported to confer health benefits. The process of biofortification through traditional plant breeding has increased the protein, provitamin A carotenoid, and zinc contents of maize. The objective of this paper is to review the innovations developed and promoted to improve the nutritional profiles of maize and outcomes of the maize agro‐food system. 相似文献
945.
946.
Vasile I. Pârvulescu Simona M. Coman Natalia Candu Jamal El Haskouri Daniel Beltrán Pedro Amorós 《Journal of Materials Science》2009,44(24):6693-6700
Strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (OTf) was incorporated into previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Catalysts with different Si/Sn ratios in the range 21.8–50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7 were found to be efficient catalysts for the etherification of primary alcohols to symmetrical long chain ethers and the selective etherification of ethylene glycol with 1-octanol to nonionic surfactants structures. The processes are green, environmentally safe, and heterogeneous. 相似文献
947.
Natalia Czaplicka Anna Grzegrska Jan Wajs Joanna Sobczak Andrzej Rogala 《International journal of molecular sciences》2021,22(17)
Providing optimal operating conditions is one of the major challenges for effective heating or cooling systems. Moreover, proper adjustment of the heat transfer fluid is also important from the viewpoint of the correct operation, maintenance, and cost efficiency of these systems. Therefore, in this paper, a detailed review of recent work on the subject of conventional and novel heat transfer fluid applications is presented. Particular attention is paid to the novel nanoparticle-based materials used as heat transfer fluids. In-depth comparison of environmental, technical, and economic characteristics is discussed. Thermophysical properties including thermal conductivity, specific heat, density, viscosity, and Prandtl number are compared. Furthermore, the possible benefits and limitations of various transfer fluids in the fields of application are taken into account. 相似文献
948.
Anna Bogda Andrzej Badeski Magorzata Pac Anna Wjcicka Marta Badeska Agnieszka Didyk Elbieta Trembecka-Dubel Nel Dbrowska-Leonik Magorzata Walaszczyk Natalia Matysiak Aurelia Morawiec-Knysak Tomasz Szczepaski Maria Szczepaska 《International journal of molecular sciences》2021,22(17)
Hemolytic uremic syndrome (HUS) is defined by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI). Atypical HUS (aHUS), distinguished by its etiology, is caused by uncontrolled overactivation of the alternative complement pathway. The correct diagnosis of aHUS is complex and involves various gene mutations. Severe combined immunodeficiency (SCID), characterized by severe T-cell lymphocytopenia and a lack of antigen-specific T-cell and B-cell immune responses, is of seldom occurrence. In 10–15% of pediatric patients, SCID is caused by adenosine deaminase (ADA) deficiency. The authors describe the case of a boy who suffered from both aHUS and ADA-deficient SCID. At the age of 9 months, the patient presented acute kidney injury with anuria and coagulopathy. The diagnosis of aHUS was established on the basis of alternative complement pathway deregulation and disease-associated gene mutations. Further examination revealed immune system failure and, at the age of 13 months, the ADA deficiency was confirmed by genetic tests and the boy was diagnosed with ADA-SCID. ADA SCID has recently been described as a possible triggering factor of aHUS development and progression. However, more research is required in this field. Nevertheless, it is crucial in clinical practice to be aware of these two co-existing life-threatening diseases. 相似文献
949.
Magdalena Chrabszczewska Maria Winiewska-Szajewska Natalia Ostrowska Elbieta Bojarska Janusz Stpiski ukasz Mancewicz Maciej ukaszewicz Joanna Trylska Micha Taube Maciej Kozak Edward Darynkiewicz Renata Grzela 《International journal of molecular sciences》2021,22(20)
Nudt16 is a member of the NUDIX family of hydrolases that show specificity towards substrates consisting of a nucleoside diphosphate linked to another moiety X. Several substrates for hNudt16 and various possible biological functions have been reported. However, some of these reports contradict each other and studies comparing the substrate specificity of the hNudt16 protein are limited. Therefore, we quantitatively compared the affinity of hNudt16 towards a set of previously published substrates, as well as identified novel potential substrates. Here, we show that hNudt16 has the highest affinity towards IDP and GppG, with Kd below 100 nM. Other tested ligands exhibited a weaker affinity of several orders of magnitude. Among the investigated compounds, only IDP, GppG, m7GppG, AppA, dpCoA, and NADH were hydrolyzed by hNudt16 with a strong substrate preference for inosine or guanosine containing compounds. A new identified substrate for hNudt16, GppG, which binds the enzyme with an affinity comparable to that of IDP, suggests another potential regulatory role of this protein. Molecular docking of hNudt16-ligand binding inside the hNudt16 pocket revealed two binding modes for representative substrates. Nucleobase stabilization by Π stacking interactions with His24 has been associated with strong binding of hNudt16 substrates. 相似文献
950.
Jacek Jassem Natalia Maria Marek-Trzonkowska Tomasz Smiatacz ukasz Arcimowicz Ines Papak Ewa Jassem Jan Maciej Zaucha 《International journal of molecular sciences》2021,22(20)
We report a lymphoma patient with profound B-cell deficiency after chemotherapy combined with anti-CD20 antibody successfully treated with remdesivir and convalescent plasma for prolonged SARS-CoV-2 infection. Viral clearance was likely attributed to the robust expansion and activation of TCR Vβ2 CD8+ cytotoxic T cells and CD16 + CD56- NK cells. This is the first presentation of TCR-specific T cell oligoclonal response in COVID-19. Our study suggests that B-cell depleted patients may effectively respond to anti-SARS-CoV-2 treatment when NK and antigen-specific Tc cell response is induced. 相似文献