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  • 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.
661

Působení aplikace hnojiv na bázi síranu amonného na výnos a olejnatost semen řepky ozimé

Vrtěl, Petr January 2019 (has links)
This thesis follow up influence of fertilization on yield and oil content of oilseed rape (Brassica napus L.). There were used fertilizers based on ammonium sulfate in the regeneration (BBCH 26, spring) and production fertilization (BBCH 31) during vegetation phase of oilseed rape. The issue was solved as a two-year small-plot field experiment carried out in the vegetation seasons 2016/2017 and 2017/2018 at the Field Experimental Station in Žabčice. The following variants were included in the experiment: Control (CAN), Ammonium sulfate (AS), Ammonium sulfate with boron (AS + B), Ammonium sulfate with nitrification inhibitor (AS + IN). Each fertilization variant was applied either as regenerative fertilization (BBCH 26) or first production fertilization (BBCH 31). The yield of seeds and also their oil content was significantly influenced by the vegetation season. Yield in the vegetation season 2017/2018 were higher by 41 % than in the vegetation season 2016/2017 because of weather conditions. The oil content was higher by 4 % in the vegetation season 2017/2018. The yield of seeds and also their oil content were not significantly influenced by the fertilization variant or by the vegetation phase of application. The highest average yield 4,23 t/ha was variant Control. The Control also was the highest average oil content of 40,2 %. High temperatures during both years reduced the efficiency of nitrification inhibitor. Fertilization with a boron-containing fertilizer had no effect because of drought and pH.
662

Electrochemical investigation of "green" film-forming corrosion inhibitors : / Elektrokemisk undersökning av "grön" filmbildande korrosionsinhibitorer :

Wang, Hansheng January 2011 (has links)
In this work, a comparative electrochemical study has been performed to evaluate corrosion inhibition property of several film-forming corrosion inhibitors provide by Akzo Nobel on carbon steel in a chloride solution. For carbon steel exposed to 1 M NaCl solution with and without added inhibitor, electrochemical measurements including electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) at different exposure time intervals, and potentiodynamic polarization at the termination of the exposure, have been performed to investigate the film forming process and to evaluate corrosion inhibition efficiency of the inhibitors, as well as its evolution with time. The corrosion resistance data obtained from the EIS and LPR measurements are in good agreement. The results indicate different inhibition properties of the inhibitors tested. The inhibition effect of SSF CI-1 is negligible in the first hour of exposure, but it increases steadily with time for 1 day, and then remains the same level during the exposure up to one week. SSF CI-2 exhibits a good inhibition effect in the first hour, but the effect decreases with time to a low level after 8 hours, and then increases again with prolonged exposure. SSF CI-4 shows a low inhibition effect during the first day, and then increases to a maximum level after three days’ exposure. For SSF CI-5 and SSF CI-6, the inhibition effect within 8 hours is relative low but higher than that of SSF CI-4, and the effect increases with time during prolonged exposure. The SSF CI-5 seems to be better than SSF CI-6 because of a more stable inhibition effect. The EIS results indicate that most of the inhibitors form a resistive surface film on carbon steel, which becomes more resistive and protective after several days’ of exposure. However, in the initial stage of exposure, the SSF CI-6 does not show an effect of formation of a resistive film on the surface. The potentiodynamic polarization measurements suggest that, SSF CI-1 and SSF CI-2 are anodic type inhibitor, SSF CI-4 is cathodic type inhibitor, and SSF CI-5 and SSF CI-6 are mix type inhibitor. Moreover, the inhibitors tested show a similar corrosion inhibition effect as mussel adhesive protein (MAP) at the low dosage level.
663

Rapid and Temporary Improvement of Depression and Anxiety Observed Following Niraparib Administration: A Case Report

Jewett, Benjamin E., Miller, Merry N., Ligon, Libby A., Carter, Zachary, Mohammad, Ibrahim, Ordway, Gregory A. 15 April 2020 (has links)
Background: Cancer patients are disproportionately affected by generalized anxiety and major depression. For many, current treatments for these conditions are ineffective. In this case report, we present a serendipitous case of anxiety and depression improvement following administration of the poly (ADP-ribose) polymerase (PARP) inhibitor niraparib. Case presentation: A 61-year old woman with a 20-year history of mild depression developed recurrent ovarian carcinoma and was placed on niraparib for maintenance chemotherapy. With the original onset of ovarian cancer, she experienced an episode of major depression that was resolved with sertraline. After recurrence of ovarian cancer, she experienced a recurrence of major depression and a new onset of generalized anxiety that failed to completely respond to multiple medications. After beginning niraparib therapy the patient noticed a rapid resolution of the symptoms of her anxiety and depression, an effect that was limited to 10-14 days. Due to bone marrow suppression, the patient was taken off and restarted on niraparib several times. Each discontinuation of niraparib resulted in return of her depression and anxiety, while each recontinuation of niraparib resulted in an improvement in her mood and anxiety. Conclusions: This case demonstrates rapid and temporary improvement of anxiety and depression following niraparib administration. There is ample preclinical data that PARP signaling may play a role in psychiatric illness. A small amount of indirect data from clinical trials also shows that niraparib may have psychiatric benefits. Further research on PARP inhibition and its potential psychoactive effects is sorely needed.
664

Rekonstitution der prämaturen Immunoseneszenz-Parameter unter anti-TNF-alpha-Therapie bei juveniler idiopathischer Arthritis / Reconstitution of Premature Immunosenescence in Juvenile Idiopathic Arthritis treated with TNFα Inhibitors

Mutterer, Angelika Christina January 2022 (has links) (PDF)
Bei juveniler idiopathischer Arthritis konnte eine prämature Immunoseneszenz nachgewiesen werden. Ein Erklärungsmodell ist, dass die prämature Immunoseneszenz den primären Defekt darstellt, der das Immunsystem zum Versagen der Selbsttoleranz führt. Eine andere Deutungsmöglichkeit stellt die prämature Immunoseneszenz als Folge von chronischer Stimulation und Aktivierung des Immunsystems durch die Autoimmunerkrankung selbst dar. In dieser Arbeit wurden die Immunoseneszenz-Parameter (naive T-Zellen, RTE, IL-7-Level, TRECs, relative Telomerlänge, Ki-67-Expression) von JIA-Patienten - unterteilt in eine DMARD-Gruppe und eine TNFα-Inhibitor-Gruppe - mit denen von gesunden Vergleichsprobanden verglichen. Eine fortgeschrittenere Immunoseneszenz bei den Gesunden könnte möglicherweise durch vermehrte chronische Virusinfekte erklärt werden, die jedoch in dieser Arbeit nicht erfasst wurden. In der vorliegenden Arbeit konnte eine potenzielle Rekonstitutionsfähigkeit mit Verbesserung der Immunoseneszenz-Parameter bei DMARD-Therapie demonstriert werden. So trat ein höherer Anteil an naiven T-Zellen und an RTE auf, was vermuten lässt, dass der fortschreitende Verlust der Thymusfunktion bei Patienten mit Autoimmunerkrankung reversibel sein könnte. Bei Vergleich der TNFi-Patienten mit der DMARD-Gruppe konnte eine weiter fortgeschrittene Immunoseneszenz festgestellt werden. Dies könnte durch die Ansammlung von schwereren, DMARD-refraktären Patienten, aber auch durch die unterschiedliche, aber nicht-signifikante Altersverteilung bedingt sein. Bei längerer Einnahmedauer des TNFα-Inhibitors zeigte sich ein tendenziell stärkeres Auftreten von naiven T-Zellen und RTE, kombiniert mit geringeren Anteilen differenzierterer Subpopulationen. So scheinen TNFα-Inhibitoren die Fähigkeit zu besitzen, die prämature Immunoseneszenz positiv zu beeinflussen oder zumindest eine Verlangsamung des prämaturen Alterungsvorgangs zu bewirken. / In juvenile idiopathic arthritis, a premature immunosenescence was shown. One possible explanation is that premature immunosenescence causes the primary defect which leads to the break-down of self-tolerance. Another possibility is that premature immunosenescence is the consequence of chronical stimulation and immune activation through the disease itself. For this dissertation, parameters of premature immunosenescence (namely naive T-cells, RTE, IL-7, TREC, RTL, expression of Ki-67) were determined in JIA patients - divided into two distinct groups with and without TNF alpha inhibitor (“DMARD”, “TNFi”) - and compared to healthy controls. More advanced immunosenescence in healthy subjects might be due to increased occurrence of chronic viral infections, which were not examined here. In DMARD, potential reconstitution with improvement of aging parameters was demonstrated. Higher percentages of naive T-cells and RTE could lead to the hypothesis that the progressive loss of thymic function might be reversible in patients with autoimmune diseases. In TNFi, parameters indicated more advanced immunosenescence. This could be explained by more severe cases of JIA, refractory to conventional treatment, or slightly, not-significant differences in the age distribution. With longer intake of TNFi, increased percentages of naive T-cells and RTE with decrease of further differentiated subsets were shown. Hence, TNFα inhibitors seem to have the ability to influence the immune system positively or to lead at least to a deceleration of the premature aging process.
665

Impact of Storage and Cryoprotectants on the Function of Cord Blood Hematopoietic Stem Cells

Jahan, Suria 30 March 2020 (has links)
Cord blood (CB) has emerged as a significant source of hematopoietic stem cells (HSC) for transplantation. Large distances between collection and processing sites combined with staff availability can lead to long processing delays of CB unit (CBU). Standard agencies limit CBU storage at room temperature (RT) to a maximum of 48 hours from collection to freezing. Slow-engraftment and graft failure are major issues related to CB transplantation. I hypothesized that prolonged storage at RT reduces the engraftment activities of CBU due to the loss in HSC numbers. I set to test my hypothesis by performing serial and limiting-dilution transplantation assays in immunodeficient mice. My results showed that the engraftment activity of CBU was significantly perturbed by prolonged storage (>40 hours) at RT. In line with my hypothesis, the transplantation assays suggested that the engraftment deficit originates from loss in HSC numbers. My findings provide results for CB banks to make an informed decision on how long CBU can be stored at RT before processing. Conversely, CBU must be cryopreserved before use, and loss of function can occur due to osmotic shock and mechanical damage from uncontrolled ice-crystal growth (ice-recrystallization) during freezing and thawing. Current cyroprotectants like dimethyl-sulfoxide fail to inhibit ice-recrystallization. However, a novel class of small ice-recrystallization inhibitor (IRI) molecules (N-aryl-D-aldonamides) have been developed. I hypothesized that supplementation of cryopreservation solution with IRIs will improve the post-thaw viability and engraftment activity of CBU. Herein, I identified two IRIs (IRI 2 and IRI 6) that improved the post-thaw recovery of hematopoietic clonogenic and multipotent progenitors. Moreover, supplementation of CB graft with IRI 2 was beneficial to engraftment and had no negative impact on the differentiation and self-renewal activities of HSCs. Taken together, my results demonstrate for the first time that IRI may be beneficial to the engraftment activity of HSC graft and support further investigation.
666

BRAF Inhibitors Stimulate CAFs to Drive Drug Resistance in Melanoma

Liu, Tianyi 04 October 2021 (has links)
No description available.
667

Wortmannin Inhibition of Forskolin-Stimulated Chloride Secretion by T84 Cells

Ecay, Tom W., Dickson, Jeffrey L., Conner, Tracy D. 31 July 2000 (has links)
The time- and dose-dependent effects of wortmannin on transepithelial electrical resistance (R(te)) and forskolin-stimulated chloride secretion in T84 monolayer cultures were studied. In both instances, maximal effects developed over 2 h and were stable thereafter. Inhibition of forskolin-stimulated chloride secretion, as measured by the short-circuit current (I(SC)) technique, had an IC50 of 200-500 nM, which is 100-fold higher than for inhibition of phosphatidylinositol 3-kinase (PI3K), but similar to the IC50 for inhibition of myosin light chain kinase (MLCK) and mitogen-activated protein kinases (MAPK). Previous work demonstrated that 500 nM wortmannin did not inhibit the cAMP activation of apical membrane chloride channels. We show here that 500 nM wortmannin has no affect on basolateral Na/K/2Cl-cotransporter activity, but inhibits basolateral membrane Na/K-ATPase activity significantly. The MLCK inhibitors ML-7 and KT5926 were without affect on forskolin-stimulated I(SC). Similarly, the p38- and MEK-specific MAPK inhibitors SB203580 and PD98059 did not reduce forskolin-stimulated I(SC). In contrast, the non-specific MAPK inhibitor apigenin reduced forskolin-stimulated I(SC) and basolateral membrane Na/K-ATPase activity similar to wortmannin. In isolated membranes from T84 cells, wortmannin did not inhibit Na/K-ATPase enzymatic activity directly. We conclude that one or more MAPK may regulate the functional expression of basolateral membrane Na/K-ATPase by controlling the abundance of enzyme molecules in the plasma membrane.
668

Retrospective Evaluation of Postoperative Bleeding Events in Patients Receiving Rivaroxaban after Undergoing Total Hip and Total Knee Arthroplasty: Comparison with Clinical Trial Data

Wood, Robert C., Stewart, David W., Slusher, Lindsey, El-Bazouni, Hadi, Cluck, David, Freshour, Jessica, Odle, Brian 01 July 2015 (has links)
Study Objective Although data from the Regulation of Coagulation in Orthopedic Surgery to Prevent Deep Venous Thrombosis and Pulmonary Embolism (RECORD) 1-4 trials have shown a similar postoperative bleeding risk between rivaroxban and enoxaparin in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA), anecdotal observations from local institutions have suggested that postoperative bleeding rates seemed higher in patients who received rivaroxaban than those reported in the RECORD trials. Thus, the objective of this pilot study was to assess postoperative bleeding events observed in clinical practice in patients receiving rivaroxaban after undergoing THA and TKA and to compare their results with those published in the RECORD trials. Design Retrospective cohort study with a comparator group of patients from the RECORD 1-4 trials. Setting Two institutions within a regional health care system. Patients Four hundred forty adults who received at least one dose of rivaroxaban 10 mg daily after undergoing THA or TKA in the two institutions between August 2011 and October 2013 (cohort group), and 6183 patients who received rivaroxaban in the RECORD 1-4 trials (comparator group). Measurements and Main Results Postoperative bleeding was assessed in the cohort patients versus the patients in the RECORD trials. The primary outcome, occurrence of any postoperative bleeding, was a composite of major and clinically relevant nonmajor bleeding as defined in the RECORD trials. Any postoperative bleeding occurred in 6.8% of the cohort patients versus 3.2% of the RECORD trial patients (p<0.0001); 1.4% of the cohort patients versus 0.38% of the RECORD trial patients suffered a major bleed (p=0.013). Within defined major bleeding, bleeding leading to reoperation and clinically overt extrasurgical site bleeding resulting in either a hemoglobin level decrease of at least 2 g/dl or transfusion of 2 units or greater of packed red blood cells were reported in 0.68% versus 0.19% (p=0.073) and 0.68% versus 0.13% (p=0.032), respectively, of the cohort patients versus the RECORD trial patients. Conclusion Overall, any postoperative bleeding in the cohort patients occurred significantly more frequently than that observed in the RECORD trial patients. The major bleeding rate was also significantly higher in the cohort patients, influenced by higher rates of bleeding leading to reoperation and clinically overt extrasurgical site bleeding resulting in either a hemoglobin decrease of at least 2 g/dl or transfusion of two units or greater of packed red blood cells. These findings from our pilot study are thought provoking and, thus, invite further investigation.
669

Twice-Daily Proton Pump Inhibitor Therapy Does Not Decrease the Frequency of Reflux Episodes During Nocturnal Recumbency in Patients With Refractory GERD: Analysis of 200 Patients Using Multichannel Intraluminal Impedance-pH Testing

Clayton, S. B., Rife, C. C., Singh, E. R., Kalbfleisch, John H., Castell, D. O. 01 November 2012 (has links)
Over half of patients with gastroesophageal reflux disease (GERD) report nocturnal symptoms. Proton pump inhibitors (PPIs) are the main medications used to treat GERD. Multichannel intraluminal impedance with pH (MII-pH) monitoring is the most sensitive method for detection and characterization of GERD. The aim of this study was to assess and compare reflux frequency in patients with refractory GERD symptoms on and off PPI therapy during the nocturnal recumbent period, as assessed by MII-pH testing. We analyzed 24-hour MII-pH studies performed in 200 patients monitored either on twice-daily (n=100) or off (n=100) PPI therapy. Demographic analysis of the on-therapy group revealed a mean age of 52 years (24-78 years) with 37% males, and the off-therapy group revealed a mean age of 49 years (18-84 years) with 40% males. All studies were interpreted to assess and characterize the number of acid and nonacid reflux episodes in the nocturnal recumbent period identified by each patient on an overnight recorder (Zephyr, Sandhill Scientific, Inc., Highlands Ranch, CO, USA). The nocturnal recumbent period was the period documented by patients during which they lie in the recumbent period at night to sleep with average periods lasting 456 and 453 minutes for patients on and off PPI therapy. There were more mean recumbent reflux episodes in the on-therapy group in comparison with the off-therapy group (3.76 mean reflux episodes [mre] per patient in the recumbent vs. 2.82 mre); the difference was not statistically significant (P=0.187). When the reflux events are classified into acid and non-acid reflux episodes, the relative occurrence of acid reflux events is less in the on-therapy group (P=0.047), while the off-therapy group have fewer nonacid reflux episodes (P=0.003). PPIs decrease the acidity of esophageal refluxate but do not decrease the relative frequency of reflux episodes in the recumbent position in patients with refractory GERD despite twice-a-day treatment with PPI therapy. The explanation for the finding of numerically increased, although not statistically significant, amount of reflux episodes in the PPI treatment group in this study, and previous studies is unclear and warrants further evaluation.
670

DNA Damage Responses in Progeroid Syndromes Arise From Defective Maturation of Prelamin A

Liu, Yiyong, Rusinol, Antonio, Sinensky, Michael, Wang, Youjie, Zou, Yue 15 November 2006 (has links)
The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their early replication arrest. Treatment of patient cells with a protein farnesyltransferase inhibitor (FTI) did not result in reduction of DNA double-strand breaks and damage checkpoint signaling, although the treatment significantly reversed the aberrant shape of their nuclei. This suggests that DNA damage accumulation and aberrant nuclear morphology are independent phenotypes arising from prelamin A accumulation in these progeroid syndromes. Since DNA damage accumulation is an important contributor to the symptoms of HGPS, our results call into question the possibility of treatment of HGPS with FTIs alone.

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