• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1428
  • 714
  • 131
  • 96
  • 66
  • 65
  • 63
  • 26
  • 26
  • 20
  • 20
  • 19
  • 16
  • 16
  • 15
  • Tagged with
  • 3179
  • 711
  • 374
  • 333
  • 319
  • 312
  • 293
  • 287
  • 286
  • 283
  • 273
  • 243
  • 237
  • 237
  • 220
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Unraveling the Role of Phenylethanolamine N-methyltransferase (Pnmt+) Cells In-vivo

Manja, Sanjana 01 January 2019 (has links) (PDF)
Phenylethanolamine N-methyltransferase (Pnmt) is the enzyme that N-methylates norepinephrine to produce the stress hormone/neurotransmitter, epinephrine, which is abundantly expressed in adrenal glands. Developmental studies have also identified Pnmt expression in the embryonic heart and several areas of the brain, including brainstem, cerebellum, and hypothalamus. Thus, we hypothesize that selective ablation of Pnmt+ cells will have detrimental effects on cardiovascular, neuromuscular, and metabolic processes. To uncover the importance of Pnmt+ cells in vivo, we generated a novel Diphtheria Toxin A (DTA) suicide model (Pnmt+/Cre; R26+/DTA) to selectively ablate Pnmt-expressing (Pnmt+) cells in mice. Appearing normal at birth, Pnmt-Cre/DTA mice began to develop apparent cardiovascular, neurological, and metabolic impairments soon thereafter. To measure cardiac function, we performed quantitative echocardiography, electrocardiography (ECG), and blood pressure measurements. Key findings from these assessments indicated decreased left-ventricular performance, slowed atrioventricular conduction, and increased pulse pressure in the Pnmt-Cre/DTA ablation mice. These mice also showed signs of motor control deficits as early as one month, which progressively worsened with age. To assess these effects, we performed standard motor tests including hind-limb clasping, grip strength, and rotarod balance tests. Moreover, we found that the Pnmt-Cre/DTA mice ceased to gain weight shortly after puberty. The motor and metabolic deficits apparent in these animals suggested potential neurological impairments, and we thus undertook immunohistochemical staining experiments to determine the localization of Pnmt+ cells in the brain. Staining revealed Pnmt expression in the Purkinje cells of the cerebellum (motor), paraventricular nucleus of the hypothalamus (metabolic), and surprisingly extensive staining in the cerebral cortex. These results demonstrate that Pnmt+ cell contributions in the brain are much more extensive than previously thought. Overall, this work opens new pathways that will have substantial impacts on our understanding of the roles Pnmt+ cells play in normal development and disorders affecting cardiovascular, motor, and metabolic functions.
92

Extracellular Vesicle-associated Biomolecules as Potential Biomarkers for Alzheimer's Disease Diagnosis

Bedoya Martinez, Lina 15 December 2022 (has links) (PDF)
Alzheimer's disease (AD) involves progressive neurodegeneration leading to the loss of normal neuronal function. Extracellular accumulation of amyloid-beta (Aß), through the abnormal cleavage of the amyloid precursor protein (APP) by ß- and γ-secretases, is one of the hallmarks of AD. Current research focuses on finding potential candidates for biomarkers and techniques with improved sensitivity for early disease detection. Extracellular vesicles (EVs) found in body fluids are a source of biomarkers for AD diagnosis. EVs transport pathologically significant biomolecules, like nucleic acids and proteins, across the blood-brain barrier, mediating local and distant cell-to-cell communication. Therefore, this study evaluated EV-associated DNA and a novel immuno-qPCR (iqPCR) technique for their prospective use in AD diagnosis. In the first part of the study, EVs secreted by AD iPS-derived neural cells (iPS-NCs) were analyzed for deviant sequences of APP DNA. Results indicate that AD EVs carry two nucleotide deletions in the sequence located upstream of the γ-secretase cleavage site, which could affect APP processing. For the second part of the study, various conditions were set up and optimized to test a novel iqPCR model for the detection of Aß. Results confirm the immunocapture of Aß and suggest that the proposed iqPCR model could detect and quantify Aß at concentrations as low as 10 picogram/mL. The differential sequences of EV-associated APP DNA and the highly sensitive iqPCR technique for the detection of Aß presented in this study create a crucial groundwork for research on early diagnosis, prognosis, and assessment of therapy response in AD.
93

Genes, markets, and the state the emergence of commercial biotechnology in the United States and Japan /

Collins, Steven Wayne. January 1994 (has links)
Thesis (Ph. D.)--University of Virginia, 1994. / Includes bibliographical references.
94

Real options and the management of R & D investment an analysis of comparative advantage, market structure, and industry dynamics in biotechnology /

Lavoie, Brian F. January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiii, 202 p.; also includes graphics. Includes abstract and vita. Advisor: Ian M. Sheldon, Dept. of Agricultural, Environmental and Development Economics. Includes bibliographical references (p. 197-202).
95

Real options and the management of R & D investment : an analysis of comparative advantage, market structure, and industry dynamics in biotechnology /

Lavoie, Brian F. January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Includes bibliographical references (p. 197-202). Also available online.
96

Planning for high technology industry in Hong Kong : a case study of biotechnology industry /

Hui, Chak-hung, Dickson. January 1994 (has links)
Thesis (M. Sc. (Urb. Plan.))--University of Hong Kong, 1994. / Includes bibliographical references (leaves 137-142).
97

Profitability, Volatility, and Risk in the Biotechnology Sector

Zucarelli, Michael, Shauffert, Maurice January 2010 (has links)
Class of 2010 Abstract / OBJECTIVES: (1) To characterize the long-term performance of the biotechnology sector and the overall market using a Sharpe Ratio analysis (excess return/volatility; α/SD). The null hypothesis tested in this paper is the generalized Sharpe ratio characteristic of the biotechnology sector is identical to that of the overall market. METHODS: 337 companies were identified using Standard Industry Classification code 2836 (Biological Products, (No Diagnostic Substances)) lists from the Center for Research and Security Prices (CRSP) and S&P CompuStat databases. Market data on equity and return were derived from securities price data from the CRSP database. Market data were used to characterize the following measures: Mean Excess Return, Mean Excess Return minus 1% of top earners (trimmed), Volatility (SD),Sharpe Ratio and 1% Adjustment RESULTS: The study finds the biotech industry earned excess returns of 13.84% over time when compared to the overall market ( 5.10%). However, these returns are highly concentrated: When the top 1% of sector earners are removed from analysis, excess return declines below the risk free rate (return of -0.05%) suggesting significant barriers to risk diversification. CONCLUSIONS: The results show the biotechnology sector experiences higher volatility compared with the overall market, as well as higher excess returns. The results justify a rejection of the null hypothesis – that the generalized Sharpe ratio of the biotechnology sector is identical to that of the overall market
98

Bioconversion of agricultural products for quality improvement.

January 2004 (has links)
Ho Wing Yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 110-123). / Abstracts in English and Chinese. / Chapter 1 --- Introduction / Chapter 1.1 --- Bioconversion --- p.1 / Chapter 1.2 --- Functional foods & quality improvement in fermentation Edible mushroom --- p.2 / Chapter 1.3 --- Substrates --- p.4 / Chapter 1.4 --- Edible mushroom --- p.6 / Chapter 1.5 --- Nutritional value of food and feed --- p.9 / Chapter 1.6 --- Protein digestibility --- p.16 / Chapter 1.7 --- Problem caused by fungal contamination --- p.17 / Chapter 1.8 --- Antioxidant --- p.18 / Chapter 1.9 --- Research objectives --- p.20 / Tables and figures --- p.21 / Chapter 2 --- Materials and Methods / Chapter 2.1 --- Materials --- p.32 / Chapter 2.2 --- Sample preparation --- p.33 / Chapter 2.3 --- Fungal growth measurement --- p.34 / Chapter 2.4 --- Proximate compositions --- p.34 / Chapter 2.4.1 --- Moisture determination --- p.34 / Chapter 2.4.2 --- Ash determination --- p.35 / Chapter 2.4.3 --- Crude lipid determination --- p.35 / Chapter 2.4.4 --- Dietary fiber determination --- p.36 / Chapter 2.4.5 --- Crude protein determination --- p.38 / Chapter 2.4.6 --- Carbohydrate determination --- p.38 / Chapter 2.4.7 --- Glucose determination --- p.39 / Chapter 2.4.8 --- Chitin determination --- p.40 / Chapter 2.4.9 --- Phytic acid determination --- p.41 / Chapter 2.5 --- In vitro protein digestibility --- p.42 / Chapter 2.6 --- Aflatoxin determination --- p.43 / Chapter 2.7 --- Antioxidant ability --- p.45 / Chapter 2.7.1 --- Ferric reducing antioxidant powder (FRAP) assay --- p.45 / Chapter 2.7.2 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.46 / Chapter 2.8 --- Statistical analysis --- p.47 / Table --- p.48 / Chapter 3 --- Results / Chapter 3.1 --- Mycelia growth --- p.49 / Chapter 3.1.1 --- Growth diameter --- p.49 / Chapter 3.1.2 --- Chitin content --- p.50 / Chapter 3.2 --- Weigh loss in sample preparation --- p.51 / Chapter 3.3 --- Proximate composition --- p.52 / Chapter 3.3.1 --- Moisture --- p.52 / Chapter 3.3.2 --- Ash --- p.52 / Chapter 3.3.3 --- Crude lipid --- p.53 / Chapter 3.3.4 --- Dietary fiber --- p.54 / Chapter 3.3.5 --- Crude protein --- p.55 / Chapter 3.3.6 --- Carbohydrate content --- p.56 / Chapter 3.3.7 --- Glucose content --- p.56 / Chapter 3.3.8 --- Phytic acid --- p.56 / Chapter 3.4 --- In vitro protein digestibility (IVPD) --- p.57 / Chapter 3.5 --- Aflatoxin --- p.53 / Chapter 3.6 --- Antioxidant ability --- p.58 / Chapter 3.6.1 --- Ferric reducing antioxidant powder (FRAP) assay --- p.58 / Chapter 3.6.2 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.60 / Tables and figures --- p.62 / Chapter 4 --- Dissusions / Chapter 4.1 --- Mycelia growth --- p.89 / Chapter 4.2 --- Weigh loss in sample preparation --- p.90 / Chapter 4.3 --- Proximate composition --- p.90 / Chapter 4.3.1 --- Moisture --- p.90 / Chapter 4.3.2 --- Ash --- p.91 / Chapter 4.3.3 --- Crude lipid --- p.92 / Chapter 4.3.4 --- Dietary fiber --- p.93 / Chapter 4.3.5 --- Crude protein --- p.96 / Chapter 4.3.6 --- Glucose concentration --- p.98 / Chapter 4.3.7 --- Phytic acid --- p.99 / Chapter 4.4 --- In vitro protein digestibility (IVPD) --- p.101 / Chapter 4.5 --- Aflatoxin --- p.102 / Chapter 4.6 --- Antioxidant activity --- p.103 / Chapter 4.7 --- Bioconversion ability --- p.105 / Chapter 4.8 --- Best substrate --- p.105 / Chapter 4.9 --- Functional foods --- p.106 / Chapter 4.10 --- Limitation of the methodology and future development --- p.107 / Table --- p.108 / Chapter 5 --- Conclusion --- p.109 / References
99

Studies on the molecular biology of the cyanobacteria Spirulina maxima

Lee, Clark P January 1989 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1989. / Includes bibliographical references (leaves 159-172) / Microfiche. / xvii, 172 leaves, bound ill. 29 cm
100

A critical evaluation of Taiwan's biotechnology industry /

Liu, Brian Chiahao. Unknown Date (has links)
Biotechnology is one of the most important emerging technologies of the 21st century and has already attracted worldwide interest. Biotechnology has been touted as the next revolution in the high technology industry following the computer-telecommunications boom. Modern biotechnology is now widely applied to almost all areas of human life, such as medicine, pharmaceuticals, agriculture, food products, energy, and environmental ecology. However, biotechnology can be said to be still in its early developmental stage and both developed and developing countries recognize its potential contribution. / Thesis (DBA(DoctorateofBusinessAdministration))--University of South Australia, 2005.

Page generated in 0.9603 seconds