1,716 research outputs found
The Value of a College Education: Estimating the Effect of Teacher Preparation on Student Achievement
No full textFederal legislation currently holds institutions of higher education accountable for the quality of teachers that they produce. However research has yet to demonstrate that teacher preparation programs (TPPs) have differential effects on the quality of teachers they produce in terms of student achievement. This study uses data from a sample of 2,582 5th grade math students in an urban school district in Kentucky and a school fixed effects design to explore the variation in average TPP effects. The authors find that TPPs are differentially effective in training teachers, which in turn impacts student performance on 5th grade math scores. There is also some indication that these differential effects converge around teachers’ fifth year of teaching.Student achievement; teacher preparation, teacher effects
Sample Preparation with Nanomaterials: Next Generation Techniques and Applications
No full textDiscover this timely, comprehensive, and up-to-date exploration of crucial aspects of the use of nanomaterials in analytical chemistry Sample Preparation with Nanomaterials: Next Generation Techniques for Sample Preparation delivers insightful and complete overview of recent progress in the use of nanomaterials in sample preparation. The book begins with an overview of special features of nanomaterials and their applications in analytical sciences. Important types of nanomaterials, like carbon nanotubes and magnetic particles, are reviewed and biological sample preparation and lab-on-a-chip systems are presented. The distinguished author places special emphasis on approaches that tend to green and reduce the cost of sample treatment processes. He also discusses the legal, economical, and toxicity aspects of nanomaterial samples. This book includes extensive reference material, like a complete list of manufacturers, that makes it invaluable for professionals in analytical chemistry. Sample Preparation with Nanomaterials offers considerations of the economic aspects of nanomaterials, as well as the assessment of their toxicity and risk. Readers will also benefit from the inclusion of: • A thorough introduction to nanomaterials in the analytical sciences and special properties of nanomaterials for sample preparation • An exploration of the mechanism of adsorption and desorption on nanomaterials, including carbon nanomaterials used as adsorbents • Discussions of membrane applications of nanomaterials, surface enhanced raman spectroscopy, and the use of nanomaterials for biological sample preparation • A treatment of magnetic nanomaterials, lab-on-a-chip nanomaterials, and toxicity and risk assessment of nanomaterials Perfect for analytical chemists, materials scientists, and process engineers, Sample Preparation with Nanomaterials: Next Generation Techniques for Sample Preparation will also earn a place in the libraries of analytical laboratories, universities, and companies who conduct research into nanomaterials and seek a one-stop resource for sample preparation
Method for sample preparation for cryoelectron microscopy (CEM) microreactor and loading platform
No full textA method for sample preparation for cryoelectron microscopy (CEM), wherein the sample is held in a microreactor, wherein the conditions in the microreactor are regulated relative to the environment, wherein the sample in the microreactor is frozen according to a quench freeze process, whereupon the sample, in frozen condition, is placed in the electron microscope. A microreactor for use with cryoelectron microscopy (CEM), comprising a first and second membrane, which membranes, at least in a condition of use, enclose a chamber, while the membranes are configured to last until at least the beginning of a quench freeze process.Applied Science
Development and progress of Ireland's biobank network: Ethical, legal, and social implications (ELSI), Standardized documentation, sample and data release, and international perspective
No full textBiobank Ireland Trust (BIT) was established in 2004 to promote and develop an Irish biobank network to benefit patients, researchers, industry, and the economy. The network commenced in 2008 with two hospital biobanks and currently consists of biobanks in the four main cancer hospitals in Ireland. The St. James's Hospital (SJH) Biobank coordinates the network. Procedures, based on ISBER and NCI guidelines, are standardized across the network. Policies and documents - Patient Consent Policy, Patient Information Sheet, Biobank Consent Form, Sample and Data Access Policy (SAP), and Sample Application Form have been agreed upon (after robust discussion) for use in each hospital. An optimum sequence for document preparation and submission for review is outlined. Once consensus is reached among the participating biobanks, the SJH biobank liaises with the Research and Ethics Committees, the Office of the Data Protection Commissioner, The National Cancer Registry (NCR), patient advocate groups, researchers, and other stakeholders. The NCR provides de-identified data from its database for researchers via unique biobank codes. ELSI issues discussed include the introduction of prospective consent across the network and the return of significant research results to patients. Only 4 of 363 patients opted to be re-contacted and re-consented on each occasion that their samples are included in a new project. It was decided, after multidisciplinary discussion, that results will not be returned to patients. The SAP is modeled on those of several international networks. Biobank Ireland is affiliated with international biobanking groups - Marble Arch International Working Group, ISBER, and ESBB. The Irish government continues to deliberate on how to fund and implement biobanking nationally. Meanwhile BIT uses every opportunity to promote awareness of the benefits of biobanking in events and in the media. Copyright © 2013, Mary Ann Liebert, Inc. 2013
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
Symposium 2: Modern approaches to nutritional research challenges: Targeted and non-targeted approaches for metabolite profiling in nutritional research.
No full textThe present report discusses targeted and non-targeted approaches to monitor
single nutrients and global metabolite profiles in nutritional research. Non-
targeted approaches such as metabolomics allow for the global description of
metabolites in a biological sample and combine an analytical platform with
multivariate data analysis to visualise patterns between sample groups. In
nutritional research metabolomics has generated much interest as it has the
potential to identify changes to metabolic pathways induced by diet or single
nutrients, to explore relationships between diet and disease and to discover
biomarkers of diet and disease. Although still in its infancy, a number of
studies applying this technology have been performed; for example, the first
study in 2003 investigated isoflavone metabolism in females, while the most
recent study has demonstrated changes to various metabolic pathways during a
glucose tolerance test. As a relatively new technology metabolomics is faced
with a number of limitations and challenges including the standardisation of
study design and methodology and the need for careful consideration of data
analysis, interpretation and identification. Targeted approaches are used to
monitor single or multiple nutrient and/or metabolite status to obtain
information on concentration, absorption, distribution, metabolism and
elimination. Such applications are currently widespread in nutritional research
and one example, using stable isotopes to monitor nutrient status, is discussed
in more detail. These applications represent innovative approaches in
nutritional research to investigate the role of both single nutrients and diet
in health and disease
Measurement of cooling rate during plunge freezing of sample preparation in cryo electron microscopy
No full textPlunge freezing is used as a sample preparation method to freeze biological samples in a vitrified thin water layer of <500nm. Typically sample is loaded on thin (<10nm) carbon membranes of a copper mesh grid. The vitrified biological sample is imaged using high resolution cryogenic transmission electron microscopy (Cryo-EM).The common practice of rapidly plunge freezing biological material prepares it to be placed in the vacuum chamber of the Cryo-EM by cooling it to a vitrified state (causing vitrification). In the present sample preparation methods, 90% of the biological materials used experience some form of contamination or damage during the transfer process and end up unusable. While improvements have been made, such as the automation of sample loading into the Cyro-EM, these improvements have brought on their own set of complications. In want of a better solution for the issues surrounding the cryo-sample preparation and loading, the research and experiments of this thesis focused on the question: is it possible for biological material to be vitrified on an Autogrid with plunge freezing? To answer this question experiments were carried out to measure the cooling rate of EM-grid and Autogrids during plunge freezing with a Vitrobot. A small thermocouple was embedded into an EM standard-grid and Autogrid glued in place with cryo-varnish. The EM-grid was then mounted onto Vitrobot tweezers and plunged into liquid ethane (cryogen). The set-up mimics to the best of its possibilities the same conditions and procedure of the standard Cyro-EM workflow and temperature was recorded at a rate of 32000 samples per second. Cooling rates measured with an EM-grid were as expected. The cooling rate of the Autogrid is slower than that of standard grid, which implies that the Vitrobot is not capable of vitrifying biological materials on an Autogrid. Research and experiments showed that the Vitrobot would probably not be capable of achieving vitrification on Autogrid because the measured cooling rate was slower then that of EM-grid. Cooling rates with the Vitrobot could be improved by a faster and deeper plunger
Robust Sample Preparation of Large-Area In- and Out-of-Plane Cross Sections of Layered Materials with Ultramicrotomy
No full textLayered materials (LMs) such as graphene or MoS2 have attracted a great deal of interest recently. These materials offer unique functionalities due to their structural anisotropy characterized by weak van der Waals bonds along the out-of-plane axis and covalent bonds in the in-plane direction. A central requirement to access the structural information on complex nanostructures built upon LMs is to control the relative orientation of each sample prior to their inspection, e.g., with transmission electron microscopy (TEM). However, developing sample preparation methods that result in large inspection areas and ensure full control over the sample orientation while avoiding damage during the transfer to the TEM grid is challenging. Here, we demonstrate the feasibility of deploying ultramicrotomy for the preparation of LM samples in TEM analyses. We show how ultramicrotomy leads to the reproducible large-scale production of both in-plane and out-of-plane cross sections, with bulk vertically oriented MoS2 and WS2 nanosheets as a proof of concept. The robustness of the prepared samples is subsequently verified by their characterization by means of both high-resolution TEM and Raman spectroscopy measurements. Our approach is fully general and should find applications for a wide range of materials as well as of techniques beyond TEM, thus paving the way to the systematic large-area mass-production of cross-sectional specimens for structural and compositional studies.QN/Conesa-Boj La
Automated high throughput IgG N-glycosylation sample preparation method development on the Tecan Freedom EVO platform
No full textGraphical abstract
Highlights
• An automated immunoglobulin G (IgG) N-glycan method was developed leveraging positive pressure technology
• In general, automated method showed satisfactory precision and agreement with manual method that is in current use
• The automated method holds the possibility to significantly streamline sample preparation, enhancing throughput and improving laboratory safety
IntroductionGlycomics, focusing on the role of glycans in biological processes, particularly their influence on the folding, stability and receptor interactions of glycoconjugates like antibodies, is vital for our understanding of biology. Changes in immunoglobulin G (IgG) N-glycosylation have been associated with various physiological and pathophysiological conditions. Nevertheless, time-consuming manual sample preparation is one of the limitations in the glycomics diagnostic implementation. The study aimed to develop an automated method for sample preparation on the Tecan Freedom Evo 200 platform and compare its efficiency and precision with the manual counterpart.
Materials and methodsThe initial method development included 32 pooled blood plasma technical replicates. An additional 24 pooled samples were used in the method comparison along with 78 random duplicates of plasma samples collected from 10,001 Dalmatians biobank to compare the manual and automated methods.
ResultsThe development resulted in a new automated method. For the automated method, glycan peaks comprising 91% of the total sample glycan showed a variation of less than 5% while 92% of the total sample showed a variation of less than 5% for the manual method. The results of the Passing-Bablok regression indicated no differences between the automated and manual methods for 12 glycan peaks (GPs). However, for 8 GPs systematic difference was present, while both systematic and proportional differences were present for four GPs.
ConclusionsThe developed automated sample preparation method for IgG glycan analysis reduced exposure to hazardous chemicals and offered a simplified workflow. Despite slight differences between the methods, the new automated method showed high precision and proved to be highly comparable to its manual counterpart
Novel nanomaterials used for sample preparation for protein analysis
No full textSample preparation is of vital importance for proteomic analysis because of the high complexity of biological samples. The rapid development of novel nanomaterials with various compositions, morphologies, and proper surface modifications provides a category of powerful tools for the sample preparation for protein analysis. In this paper, we have summarized recent progresses for the applications of novel nanomaterials in sample preparation for the analysis of proteomes, especially for phosphoproteomes, glycoproteomes, and peptidoms. Several kinds of novel nanomaterials were also discussed for their use in other kinds of proteomics analysis.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000329092900010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemical Research MethodsChemistry, AnalyticalSCI(E)[email protected]
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