196,657 research outputs found
The relative contributions of physical and microbiological factors to cohesive sediment stability
No full textThe stabilising effects of natural benthic diatom and bacterial assemblages on cohesive sediments were compared with those caused by physico-chemical binding alone. Cohesive sediment beds were reconstructed in 4 annular laboratory miniflumes, using sediment collected at 5–6 m water depth from a local fjord. The sediment was left to stabilise (consolidate) for 1, 2, 5 and 10 days, before being fully resuspended in a series of erosion experiments. The flumes were aerated and subjected to different light/dark conditions; antibiotics were used to isolate diatom from bacteria effects. During consolidation, a constant current velocity was maintained, at a speed well below erosion threshold.‘Natural’ sediment regained 27% of its original stability after 1 day, and 85% after 5 days. Complete ‘natural’ sediment stability was regained within 10 days. Benthic diatoms (mainly Nitzchia sp., Gyrosigma sp. and Pennales sp.) were responsible for about 80% of the biostabilisation, whilst bacteria contributed 12%, indicating the importance of light as a controlling factor for surface sediment stability. Relative to physico-chemical binding, the increase in erosion threshold induced by benthic diatoms was 120%, and by bacteria 20%. Where the assemblage consisted of both diatoms and bacteria, the increase was 150%, indicating that natural bed values are not a simple summation of the two effects, i.e. diatoms plus bacteria. Using the results, a first generation empirical relationship describing the relative contributions of microbenthic and physico-chemical factors in the development of erosion threshold is presented. Empirical relationships containing biostabilisation coefficients are important for better computer model predictions of sediment transport. <br/
The role of economic evaluations in health care decision making
No full textIncreasing health care expenditures, a rapid introduction of new medical technologies and a need for cost containment policies in most countries during the last decades have led to a growing interest in information from economic evaluations for decision making about resource allocation in health care. Economic evaluations can provide valuable information in many types of decision making, e.g. related to the use of drugs, other health care interventions/programs and investments in new technologies or research. These are, however, currently most widely used in pricing and reimbursement decisions for new drugs, in health technology assessment and for development of guidelines for prevention and treatment.This thesis discusses the role of economic evaluations in different types of health care decision making concerning resource allocation. Two of the studies analyse the available costeffectiveness evidence for new drugs. The other four studies discuss and provide costeffectiveness information to be used in the following important types of decision making situations in Sweden: reimbursement of new drugs, investments in new technology, implementation of screening programs and choices between therapies.The publication of economic evaluations increased dramatically during the 1980's and 1990's. This thesis demonstrates that economic evaluations during the 1990's were more likely to be conducted for drugs with improved effectiveness or safety as compared to those of the competitors and for drugs with high sales. Although requirements for economic evaluations for reimbursement decisions may lead to a more cost-effective use of the resources, it is important to recognise that regulations also involve a cost. Increasing requirements for cost-effectiveness in Sweden and Finland may have been associated with a delayed introduction of new drugs on the market, at least the first year after the changed regulations. However, it cannot be ruled out that the observed data might be due to chance or adaptations in the timing of new drug introductions.This thesis discusses four types of decision making where cost-effectiveness information can be of value for the decisions. The four economic evaluations identified patient populations and indications where teriparatide treatment for osteoporosis, proton radiation for breast cancer, screening for abdominal aortic aneurysm in men and use of iodixanol in angiography may be considered cost-effective in Sweden.List of scientific papersI. Lundkvist J, Jonsson B, Rehnberg C (2005). Cost-effectiveness of new drugs: a systematic review of published evidence for new chemical entity drugs introduced on the Swedish market 1987-2000. Int J Technol Assess Health Care. 21(2): 187-93. https://pubmed.ncbi.nlm.nih.gov/15921058 II. Lundkvist J, Jonsson B, Rehnberg C (2005). The costs and benefits of increased reimbursement regulations for new drugs. [Manuscript]III. Lundkvist J, Johnell O, Cooper C, Sykes D (2005). Economic evaluation of parathyroid hormone (PTH) in the treatment of osteoporosis in postmenopausal women. Osteoporosis International. [Accepted] https://doi.org/10.1007/s00198-005-1959-4 IV. Lundkvist J, Ekman M, Ericsson SR, Isacsson U, Jonsson B, Glimelius B (2005). Economic evaluation of proton radiation therapy in the treatment of breast cancer. Radiother Oncol. 75: 179-85. https://doi.org/10.1016/j.radonc.2005.03.006 V. Wanhainen A, Lundkvist J, Bergqvist D, Bjorck M (2005). Cost-effectiveness of different screening strategies for abdominal aortic aneurysm. J Vasc Surg. 41(5): 741-51; discussion 751. https://doi.org/10.1016/j.jvs.2005.01.055 VI. Aspelin P, Aubry P, Fransson SG, Strasser R, Willenbrock R, Lundkvist J (2005). Cost-effectiveness of iodixanol in patients at high risk of contrast-induced nephropathy. Am Heart J. 149(2): 298-303. https://doi.org/10.1016/j.ahj.2004.07.020 </p
Importance of organic farming research in Sweden for innovations and increased sustainability in agriculture
No full textOrganic farming is known to be a knowledge intensive production system and there is a strong need for new knowledge and innovations to achieve increased sustainability. Furthermore, many of the research goals defined in national and international research strategies for organic agriculture are addressing questions relating to the development of more sustainable food and farming systems in general. Organic systems can thus be seen as a fore-runner and an innovation system to sustainable food and farming (TP Organics, 2009; EPOK, 2013)
Anti-drug antibodies in patients with multiple sclerosis
No full textMultiple sclerosis (MS) is an inflammatory disease affecting the brain and spinal cord and it is the main cause of neurological disability among young adults. Recombinant interferon beta (IFNβ) and natalizumab are commonly used disease-modifying drugs that reduce disease severity. Even though these treatments show beneficial clinical effects they are associated with the development of anti-drug antibodies (ADAs), which at high titer levels reduce drug efficacy. Although ADAs are known to adversely affect the clinical effect of the treatment on a group level, the treatment response in individual patients is less characterized. In addition, it is unknown why only a subgroup of treated MS patients develops ADAs. The objective of this thesis was to identify biologically relevant ADA titer cut-points that can be used to predict treatment response and persistence of ADAs in individual patients, and to investigate if genetic and immunological factors influence the development of ADAs in MS patients.MS patients analyzed for the presence of ADAs against IFNβ or natalizumab in the routine NAb laboratory at Karolinska Institutet were included in this project. In Sweden, NAb monitoring became clinical practice in 2003 and during 2003-2004 the overall seroprevalence of neutralizing antibodies (NAbs) against IFNβ was 32%. When the NAb seroprevalence was analyzed five years later, in 2009-2010, the overall frequency of NAb-positive patients had decreased significantly to 19%. Importantly, the greatest reduction was observed in patients with high NAb titers (study I). By correlating the in vivo IFNβ bioactivity with patients’ NAb titers we identified that a NAb titer of 150 TRU/ml is a biologically functional cut-point for treatment response, since titers above 150 TRU/ml completely block IFNβ bioactivity (study II). Furthermore, characterization of ADA responses in natalizumab-treated patients revealed that the level of total anti-natalizumab antibodies in a first positive sample can be used to predict patients at risk of becoming persistently antibody positive (study V).It is known that factors such as protein modifications and/or impurities impact the immunogenicity of IFNβ, which can explain the variation in NAb positivity between IFNβ preparations. In addition, since only a subgroup of IFNβ-treated patients develops NAbs, patient-related factors are likely to influence the immunogenicity of IFNβ. In study III, we hypothesized that MS patients with and without intrathecal production of oligoclonal IgG bands (OCB) have different propensities to induce humoral immune responses. The presence of OCB was found to be associated with NAb development, and this risk was confined to NAbs against IFNβ-1a. From these results we proposed that MS patients with and without OCB differ immunologically, potentially influenced by distinct human leukocyte antigen (HLA) alleles. The role of HLA in the immunogenicity of IFNβ was further investigated in study IV, in which we found that HLA-DRB1*15 carriage was associated with increased risk of developing NAbs. Stratification on type of IFNβ preparation showed that HLA-DRB1*15 increased the risk of NAbs against IFNβ-1a, while HLA-DRB1*04 increased the risk of NAbs against IFNβ-1b, indicating that there is an IFNβ preparation-specific genetically determined risk to develop NAbs.Overall, these results can be used to assist when making decisions about whether treatment should be discontinued or not. In addition, the identification of factors contributing to the immunogenicity of protein therapeutics can increase our understanding of the immunological mechanisms leading to ADA responses, possibly resulting in less immunogenic drugs in the future.List of scientific papersI. Prevalence of anti-drug antibodies against interferon beta has decreased since routine analysis of neutralizing antibodies became clinical practice. Jungedal R, Lundkvist M, Engdahl E, Ramanujam R, Westerlind H, Sominanda A, Hillert J, Fogdell-Hahn A. Multiple Sclerosis Journal 2012 Dec;18(12):1775-81. https://doi.org/10.1177/1352458512446036 II. Anti-interferon beta antibody titers strongly correlate between two bioassays and in vivo biomarker expression, and indicate that a titer greater than 150 TRU/ml is a biologically functional cut-point. Hermanrud C, Lundkvist Ryner M, Engdahl E, Fogdell-Hahn A. [Accepted] https://pubmed.ncbi.nlm.nih.gov/24444338 III. Multiple sclerosis patients lacking oligoclonal bands in the cerebrospinal fluid are less likely to develop neutralizing antibodies against interferon beta. Lundkvist M, Greiner E, Hillert J, Fogdell-Hahn A. Multiple Sclerosis Journal. 2010 Jul;16(7):796-800. https://doi.org/10.1177/1352458510373112 IV. Human leukocyte antigen genes and interferon beta preparation influence on risk of developing neutralizing anti-drug antibodies in multiple sclerosis. Link J, Lundkvist Ryner M, Fink K, Hermanrud C, Lima I, Brynedal B, Kockum I, Hillert J, Fogdell-Hahn A. [Submitted]V. Characterization of anti-natalizumab antibodies in multiple sclerosis patients. Lundkvist M, Engdahl E, Holmén C, Movérare R, Olsson T, Hillert J, Fogdell-Hahn A. Multiple Sclerosis Journal. 2013 May;19(6):757-64. https://doi.org/10.1177/1352458512462920 </p
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
Circadian rhythm dysfunction in the suprachiasmatic nucleus : effects of Trypanosoma brucei brucei infection and inflammatory cytokines
No full textAlterations in the mammalian circadian pacemaker, the hypothalamic suprachiasmatic nuclei (SCN), were studied in an experimental rat model of African trypanosomiasis, or sleeping sickness, caused by infections with subspecies of Trypanosoma brucei (T b). Characteristic signs of the disease are marked disturbances in circadian rhythms, such as a fragmentation of the sleep-wake cycle. Circadian rhythms are mastered from neurons in the SCN, which have an endogenous rhythm of spontaneous firing that is increased during the subjective day. The SCN rhythm can be recorded as spontaneous single unit activity in slice preparations containing the SCN. This activity was recorded in slices from controls and rats infected with T. b. brucei. The rhythm in spontaneous neuronal activity was markedly altered in trypanosome-infectec rats, with a lower average frequency and a phase advance of the peak. No structural differences in the retinal afferents were detected.The spontaneous postsynaptic activity was analyzed in slices by whole cell patch clamp recordings of S CN neurons. The inhibitory and excitatory postsynaptic events were identified as primarily gamma- ammobutyric acid (GABA) A and alpha-amino-hydroxy-5-mothyhsoxazole-4propionic acid (AMPA) receptor- dependent. The inhibitory and excitatory activity was compared between the subjective day and night in control rats. No significant difference was detected in amplitude or frequency of inhibitory synaptic events, but die frequency of excitatory events was significantly increased during the subjective day. In slices from rats infected with T. b. brucei, the frequency of excitatory events was significantly lower during the subjective day as compared with control rats. In addition, the protein expressions of AMPA glutamate receptor subunit 2 & 3, and N-methyl-D-aspartate receptor channel subunit zeta1 (NMDAR1), were decreased in trypanosome-infected rats.Invasion of trypanosomes causes a substantial release of several cytokines as an immune response to the infection, for instance tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma, which act in synergy. TNF-alpha and IFN-gamma in combination with bacterial lipopolysaccharide were added to SCN slices and the spontaneous firing was examined. The cytokines altered the rhythm in firing frequency; i. c. caused an abolishment or shift of the peak.The transcript and protein of the IFN-gamma receptor (IFN-gammaR) was detected in the SCN. The molecular identity of the receptor transcript was determined, confirming that the receptor molecule was identical to the IFN-gammaR in the immune system. The expression of the receptor, protein showed daily variations with a peak of expression during the early subjective night. The cyclic variation was abolished and the protein levels were increased in rats held in constant darkness. The postnatal development of the IFN- gammaR protein was studied. At postnatal day (P) 1 the protein was distributed throughout the entire nuclei, but relocated to the ventrolateral retinorecipient subdivisions of the SCN between P l 1 and P20.In conclusion, the present findings demonstrate that T. b. brucei dysregulates the endogenous rhythm in SCN activity, which probably alters the circadian output and may be manifested as a fragmentation of the sleep-wake cycle. Further, the SCN contain glutamatergic synapses that display an increase in activity during the subjective day in vitro. This activity is decreased in slices from trypanosome-infected rats, possibly explaining the observed alteration in spontaneous firing. Cytokines released during trypanosome- infections, such as IFN-gamma may affect protein expression of glutamate receptors and glutamatergic postsynaptic transmission via its receptor, which is located in the ventralateral regions of the SCN.List of scientific papersI. Lundkvist GB, Christenson J, ElTayeb RA, Peng ZC, Grillner P, Mhlanga J, Bentivoglio M, Kristensson K (1998). "Altered neuronal activity rhythm and glutamate receptor expression in the suprachiasmatic nuclei of Trypanosoma brucei-infected rats. " J Neuropathol Exp Neurol 57(1): 21-9 https://pubmed.ncbi.nlm.nih.gov/9600194II. Lundkvist GB, Kristensson K, Hill RH (2001). "The suprachiasmatic nucleus exhibits diurnal variations in spontaneous excitatory postsynaptic activity." (Submitted)III. Lundkvist GB, Hill RH, Kristensson K (2001). "Trypanosoma brucei brucei infection and pro-inflammatory cytokines alter synaptic activity and firing frequency in the rat suprachiasmatic nuclei." (Manuscript)IV. Lundkvist GB, Robertson B, Mhlanga JD, Rottenberg ME, Kristensson K (1998). "Expression of an oscillating interferon-gamma receptor in the suprachiasmatic nuclei. " Neuroreport 9(6): 1059-63 https://pubmed.ncbi.nlm.nih.gov/9601667V. Lundkvist GB, Andersson A, Robertson B, Rottenberg ME, Kristensson K (1999). "Light-dependent regulation and postnatal development of the interferon-gamma receptor in the rat suprachiasmatic nuclei. " Brain Res 849(1-2): 231-4 https://pubmed.ncbi.nlm.nih.gov/10592307</p
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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