196,832 research outputs found
Directing stem cell differentiation with antibodies.
No full textStem cells are highly specialized cells endowed with unlimited replicative self-renewing potential. These cells are capable of either limited multipotent (adult stem cells, ASC) or unlimited pluripotent (embryonic stem cells, ESC) differentiation to somatic cell lineages. Control of this differentiation process holds great promise in areas such as tissue regeneration and the treatment of chronic degenerative diseases. The medical exploitation of this phenomenon is carried out using stem cells derived from different sources (e.g., ASC/ESC), developmental stages (e.g., mesenchymal cells), cellular reprogramming (e.g., induced pluripotent stem cells), or even nonstem cells in a process known as transdifferentiation (Fig. 1). Despite this wide diversity, all of the differentiation steps that drive these cells to the desired somatic cell lineage rely on the directed manipulation of endogenous pathways. This process is achieved primarily by direct ligand signaling to cell-surface receptors, or use of distinct combinations of transcription factors derived from these signals. Now in PNAS, Melidoni et al. (1), building upon earlier reports (2, 3), raise the exciting possibility of using combinatorial library-derived antibodies intimately linked to stem-cell phenotype as a powerful tool in controlling these differentiation events
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Glycosylation and the immune system
No full textAlmost all of the key molecules involved in the innate and adaptive immune response are glycoproteins. In the cellular immune system, specific glycoforms are involved in the folding, quality control, and assembly of peptide-loaded major histocompatibility complex (MHC) antigens and the T cell receptor complex. Although some glycopeptide antigens are presented by the MHC, the generation of peptide antigens from glycoproteins may require enzymatic removal of sugars before the protein can be cleaved. Oligosaccharides attached to glycoproteins in the junction between T cells and antigen-presenting cells help to orient binding faces, provide protease protection, and restrict nonspecific lateral protein-protein interactions. In the humoral immune system, all of the immunoglobulins and most of the complement components are glycosylated. Although a major function for sugars is to contribute to the stability of the proteins to which they are attached, specific glycoforms are involved in recognition events. For example, in rheumatoid arthritis, an autoimmune disease, agalactosylated glycoforms of aggregated immunoglobulin G may induce association with the mannose-binding lectin and contribute to the pathology
Structure and dynamics in oligomannose-type oligosaccharides. Biochemistry
No full textABSTRACT: Using a combination of 'H N M R nuclear Overhauser effect measurements, molecular orbital calculations, and molecular dynamics simulations, we have determined the tertiary structure and dynamic properties of the oligomannose oligosaccharide Mana6(Mana3)Mana6(Mana3)Manp4GlcNAc~4GlcNAc. While the calculated potential surfaces for the majority of the glycosidic linkages could be described by a single deep potential well, similar calculations for the M a n a l d M a n a and Mana 1-6Manp linkages described a diffuse, shallow well, suggesting that a larger degree of flexibility exists about the latter. These conclusions are supported by the results of molecular dynamics simulations, which suggest that the N M R data should be interpreted in terms of a degree of flexibility about the M a n a l d M a n p and Manal-6Mana linkages. In contrast, a similar series of investigations suggests that the conformation of the M a n a l d M a n B linkage in Mana2Man6(Mana2Man~3)Mana6(Mana2Mana2Mana3)Man~4GlcNAc~4GlcNAc is more restricted, resulting in an overall structure that is "restrained". High-resolution *H nuclear magnetic resonance is a well-established method for the derivation of the three-dimensional structures of biomolecules in solution. The use of two-di-mensional coherence-transfer methods such as 'H-lH corre
Direct deprotected glycosyl-asparagine ligation
No full textA simple and efficient synthesis of N-linked glycoamino acids and glycopeptides from deprotected sugars using the Staudinger reactio
The dust budget crisis in high-redshift submillimetre galaxies
No full textKR acknowledges support from the European Research Council Starting Grant (P.I. V. Wild). HLG acknowledges support from the Science, Technology and Facilities Council.We apply a chemical evolution model to investigate the sources and evolution of dust in a sample of 26 high-redshift (z > 1) submillimetre galaxies (SMGs) from the literature, with complete photometry from ultraviolet to the submillimetre. We show that dust produced only by low-intermediate-mass stars falls a factor 240 short of the observed dust masses of SMGs, the well-known 'dust-budget crisis'. Adding an extra source of dust from supernovae can account for the dust mass in 19 per cent of the SMG sample. Even after accounting for dust produced by supernovae the remaining deficit in the dust mass budget provides support for higher supernova yields, substantial grain growth in the interstellar medium or a top-heavy IMF. Including efficient destruction of dust by supernova shocks increases the tension between our model and observed SMG dust masses. The models which best reproduce the physical properties of SMGs have a rapid build-up of dust from both stellar and interstellar sources and minimal dust destruction. Alternatively, invoking a top-heavy IMF or significant changes in the dust grain properties can solve the dust budget crisis only if dust is produced by both low-mass stars and supernovae and is not efficiently destroyed by supernova shocks.Peer reviewe
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
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