Academic literature on the topic 'GI function'
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Journal articles on the topic "GI function"
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Shklennik, Maria A., and Alexander N. Moiseev. "Method of Markovian summation for study the repeated flow in queueing tandem M|GI|∞ → GI|∞." Izvestiya of Saratov University. New Series. Series: Mathematics. Mechanics. Informatics 21, no. 1 (February 24, 2021): 125–37. http://dx.doi.org/10.18500/1816-9791-2021-21-1-125-137.
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The paper presents a mathematical model of queueing tandem M|GI|∞ → GI|∞ with feedback. The service times at the first stage are independent and identically distributed (i.i.d.) with an arbitrary distribution function B1(x). Service times at the second stage are i.i.d. with an arbitrary distribution function B2(x). The problem is to determine the probability distribution of the number of repeated customers (r-flow) during fixed time period. To solve this problem, the Markov summation method was used, which is based on the consideration of Markov processes and the solution of the Kolmogorov equation. In the course of the solution, the so-called local r-flow was studied — the number of r-flow calls generated by one incoming customer received by the system. As a result, an expression is obtained for the characteristic probability distribution function of the number of calls in the local r-flow, which can be used to study queuing systems with a similar service discipline and non-Markov incoming flows. As a result of the study, an expression is obtained for the characteristic probability distribution function of the number of repeated calls to the system at a given time interval during non-stationary regime, which allows one to obtain the probability distribution of the number of calls in the flow under study, as well as its main probability characteristics.
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Cooper, Simon B., Stephan Bandelow, Maria L. Nute, John G. Morris, and Mary E. Nevill. "Breakfast glycaemic index and cognitive function in adolescent school children." British Journal of Nutrition 107, no. 12 (September 29, 2011): 1823–32. http://dx.doi.org/10.1017/s0007114511005022.
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It has been suggested that a low-glycaemic index (GI) breakfast may be beneficial for some elements of cognitive function (e.g. memory and attention), but the effects are not clear, especially in adolescents. Thus, the aim of the present study was to examine the effects of a low-GI breakfast, a high-GI breakfast and breakfast omission on cognitive function in adolescents. A total of fifty-two adolescents aged 12–14 years were recruited to participate in the study. Participants consumed a low-GI breakfast, a high-GI breakfast or omitted breakfast. A battery of cognitive function tests was completed 30 and 120 min following breakfast consumption and capillary blood samples were taken during the 120 min postprandial period. The findings show that there was a greater improvement in response times following a low-GI breakfast, compared with breakfast omission on the Stroop (P = 0·009) and Flanker (P = 0·041) tasks, and compared with a high-GI breakfast on the Sternberg paradigm (P = 0·013). Furthermore, accuracy on all three tests was better maintained on the low-GI trial compared with the high-GI (Stroop:P = 0·039; Sternberg:P = 0·018; Flanker:P = 0·014) and breakfast omission (Stroop:P < 0·001; Sternberg:P = 0·050; Flanker:P = 0·014) trials. Following the low-GI breakfast, participants displayed a lower glycaemic response (P < 0·001) than following the high-GI breakfast, but there was no difference in the insulinaemic response (P = 0·063) between the high- and low-GI breakfasts. Therefore, we conclude that a low-GI breakfast is most beneficial for adolescents' cognitive function, compared with a high-GI breakfast or breakfast omission.
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Brandoli, Claudio, Cesar Petri, Marcos Egea-Cortines, and Julia Weiss. "Gigantea: Uncovering New Functions in Flower Development." Genes 11, no. 10 (September 28, 2020): 1142. http://dx.doi.org/10.3390/genes11101142.
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GIGANTEA (GI) is a gene involved in multiple biological functions, which have been analysed and are partially conserved in a series of mono- and dicotyledonous plant species. The identified biological functions include control over the circadian rhythm, light signalling, cold tolerance, hormone signalling and photoperiodic flowering. The latter function is a central role of GI, as it involves a multitude of pathways, both dependent and independent of the gene CONSTANS(CO), as well as on the basis of interaction with miRNA. The complexity of the gene function of GI increases due to the existence of paralogs showing changes in genome structure as well as incidences of sub- and neofunctionalization. We present an updated report of the biological function of GI, integrating late insights into its role in floral initiation, flower development and volatile flower production.
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Greenwood-Van Meerveld, B. "Abnormalites in GI function associated with inflammation." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 124 (August 1999): S15. http://dx.doi.org/10.1016/s1095-6433(99)90059-4.
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He, Hongzhi, and Joomyeong Kim. "Regulation and Function of the Peg3 Imprinted Domain." Genomics & Informatics 12, no. 3 (2014): 105. http://dx.doi.org/10.5808/gi.2014.12.3.105.
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Mahdaleny and Febriana Catur Iswanti. "Gut microbiome diversity as adjuvant marker for immune function." Acta Biochimica Indonesiana 5, no. 1 (June 21, 2022): 80. http://dx.doi.org/10.32889/actabioina.80.
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The gastrointestinal (GI) tract represents our most intimate contact with the external environment. The GI tract responsible for extracting the appropriate nutrients we need to thrive, maintaining an appropriate balance of helpful and harmful microbes, and acting as a conduit for waste removal. In essence, the extracellular matrix of gut mucosal biofilm is a complex network of microbes and their secretions, as well as the host's secretions and signals (mainly mucus/mucin). Mucin, bacterial polysaccharides, and protein combine to form a unique mucosal biofilm that serves as a home for a variety of commensal and pathogenic organisms in the host. Maintaining proper mucosal barrier function is vital for both GI and systemic health. The lumen of the gut contains numerous entities that should never reach the bloodstream or lymphatic system. The mucosal barrier's integrity is maintained by a single layer of tightly fitted columnar epithelial, and more than 70% of the immune system components are closely associated with the GI tract.
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Gaesser, Rodriguez, Patrie, Whisner, and Angadi. "Effects of Glycemic Index and Cereal Fiber on Postprandial Endothelial Function, Glycemia, and Insulinemia in Healthy Adults." Nutrients 11, no. 10 (October 6, 2019): 2387. http://dx.doi.org/10.3390/nu11102387.
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Both glycemic index and dietary fiber are associated with cardiovascular disease risk, which may be related in part to postprandial vascular effects. We examined the effects of both glycemic index (GI) and dietary (mainly cereal) fiber on postprandial endothelial function. Eleven adults (5 men; 6 women; age = 42.4 ± 16.1 years; weight = 70.5 ± 10.7 kg; height = 173.7 ± 8.7 cm) consumed four different breakfast meals on separate, randomized occasions: High-Fiber, Low-GI (HF-LGI: Fiber = 20.4 g; GI = 44); Low-Fiber, Low-GI (LF-LGI: Fiber = 4.3 g; GI = 43); Low-Fiber, High-GI (LF-HGI: Fiber = 3.6 g; GI = 70); High-Fiber, High-GI (HF-HGI: Fiber = 20.3 g; GI = 71). Meals were equal in total kcal (~600) and macronutrient composition (~90 g digestible carbohydrate; ~21 g protein; ~15 g fat). The HF-LGI meal resulted in a significant increase in flow-mediated dilation (FMD) 4 hours after meal ingestion (7.8% ± 5.9% to 13.2% ± 5.5%; p = 0.02). FMD was not changed after the other meals. Regardless of fiber content, low-GI meals resulted in ~9% lower 4-hour glucose area under curve (AUC) (p < 0.05). The HF-LGI meal produced the lowest 4-hour insulin AUC, which was ~43% lower than LF-HGI and HF-HGI (p < 0.001), and 28% lower than LF-LGI (p = 0.02). We conclude that in healthy adults, a meal with low GI and high in cereal fiber enhances postprandial endothelial function. Although the effect of a low-GI meal on reducing postprandial glucose AUC was independent of fiber, the effect of a low-GI meal on reducing postprandial insulin AUC was augmented by cereal fiber.
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Martínez-Herrero, Sonia, and Alfredo Martínez. "Adrenomedullin: Not Just Another Gastrointestinal Peptide." Biomolecules 12, no. 2 (January 18, 2022): 156. http://dx.doi.org/10.3390/biom12020156.
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Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two bioactive peptides derived from the same precursor with several biological functions including vasodilation, angiogenesis, or anti-inflammation, among others. AM and PAMP are widely expressed throughout the gastrointestinal (GI) tract where they behave as GI hormones, regulating numerous physiological processes such as gastric emptying, gastric acid release, insulin secretion, bowel movements, or intestinal barrier function. Furthermore, it has been recently demonstrated that AM/PAMP have an impact on gut microbiome composition, inhibiting the growth of bacteria related with disease and increasing the number of beneficial bacteria such as Lactobacillus or Bifidobacterium. Due to their wide functions in the GI tract, AM and PAMP are involved in several digestive pathologies such as peptic ulcer, diabetes, colon cancer, or inflammatory bowel disease (IBD). AM is a key protective factor in IBD onset and development, as it regulates cytokine production in the intestinal mucosa, improves vascular and lymphatic regeneration and function and mucosal epithelial repair, and promotes a beneficial gut microbiome composition. AM and PAMP are relevant GI hormones that can be targeted to develop novel therapeutic agents for IBD, other GI disorders, or microbiome-related pathologies.
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NELSON, ROXANNE. "Novel Agent Improves GI Function in Pain Patients." Clinical Psychiatry News 34, no. 10 (October 2006): 58. http://dx.doi.org/10.1016/s0270-6644(06)71839-2.
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Moss, Gerald. "QS70. Automatically Titrating Feeding to Match GI Function." Journal of Surgical Research 144, no. 2 (February 2008): 296–97. http://dx.doi.org/10.1016/j.jss.2007.12.309.
Full textDissertations / Theses on the topic "GI function"
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Han, Jing. "ROLE OF THE REGULATOR OF G PROTEIN SIGNALING 2 (RGS2) FOR NEURONAL AND SYSTEM FUNCTION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=case1175703706.
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Karlgren, Anna, Niclas Gyllenstrand, Thomas Källman, and Ulf Lagercrantz. "Conserved function of core clock proteins in the gymnosperm Norway spruce (Picea abies L. Karst)." Uppsala universitet, Växtekologi och evolution, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192151.
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From studies of the circadian clock in the plant model species Arabidopsis (Arabidopsis thaliana), a number of important properties and components have emerged. These include the genes CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), GIGANTEA (GI), ZEITLUPE (ZTL) and TIMING OF CAB EXPRESSION 1 (TOC1 also known as PSEUDO-RESPONSE REGULATOR 1 (PRR1)) that via gene expression feedback loops participate in the circadian clock. Here, we present results from ectopic expression of four Norway spruce (Picea abies) putative homologs (PaCCA1, PaGI, PaZTL and PaPRR1) in Arabidopsis, their flowering time, circadian period length, red light response phenotypes and their effect on endogenous clock genes were assessed. For PaCCA1-ox and PaZTL-ox the results were consistent with Arabidopsis lines overexpressing the corresponding Arabidopsis genes. For PaGI consistent results were obtained when expressed in the gi2 mutant, while PaGI and PaPRR1 expressed in wild type did not display the expected phenotypes. These results suggest that protein function of PaCCA1, PaGI and PaZTL are at least partlyconserved compared to Arabidopsis homologs, however further studies are needed to reveal the protein function of PaPRR1. Our data suggest that components of thethree-loop network typical of the circadian clock in angiosperms were present beforethe split of gymnosperms and angiosperms.
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Fikree, Asma. "Functional gastrointestinal disorders and the joint hypermobility syndrome." Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8301.
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Despite the fact that functional gastrointestinal disorders (FGID), such as irritable bowel syndrome, are common, our understanding of them is limited. The Joint Hypermobility Syndrome (JHS) is a common non-inflammatory connective tissue disorder which is thought to be associated with FGID although this has never been proven. Thus, further understanding of the link between JHS and GI symptoms is warranted. Our aim was to fully characterise the gastrointestinal (GI) manifestations of JHS, to determine if there is a true association between GI symptoms in JHS and FGID, and to determine the factors that are involved in this association. Using a cross-sectional design I demonstrate in the first study that patients with a known diagnosis of JHS who are referred from rheumatologists to gastroenterologists have significantly increased gastro-oesophageal symptoms, alternating bowel habit, bloating and abdominal pain compared to other patients referred to the GI clinics. Autonomic factors, and to a lesser extent, somatic hypersensitivity factors appear to mediate the association between JHS and gastro-oesophageal symptoms. In the second study, I demonstrate that healthy university students with JHS are more likely to experience postprandial dyspeptic symptoms compared to those without JHS. Although autonomic and somatic symptoms are increased in JHS their presence does not seem to confound the association with GI symptoms in this group of healthy individuals. In a case-control study of patients attending secondary care GI clinics, I demonstrate that JHS is overrepresented in patients with FGID and reflux disease but not in those with organic disease. Furthermore, the association with FGID is specifically with postprandial distress syndrome and this association is dependent on autonomic factors. In the final chapter, I confirm that abnormalities in GI physiology are common in JHS patients with GI symptoms attending a physiology unit. 60% of JHS patients with reflux symptoms have non-erosive pathological acid reflux, 56% with dysphagia have oesophageal hypomotility, and 87% with dyspeptic symptoms have gastroparesis. My studies suggest that there is overlap between JHS, gastro-oeosphageal symptoms, FGID and GI dysmotility. Understanding the mechanisms underlying GI involvement in JHS may further our understanding of FGID.
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Drusiani, Alberto. "Conversione in OCaml della libreria ocaml-gi-gtk." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23335/.
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L’utilizzo in larga scala della libreria grafica GTK implementata in C ha forzato gli sviluppatori della stessa a rendere semplice la creazione di binding ad essa con linguaggi
di alto livello. Esistono due tipi di binding: manuale e automatico. Il binding automatico permette di svincolarsi dalle modifiche che vengono effettuate a GTK, rendendo
il processo di binding più robusto. OCaml, linguaggio di programmazione emergente e
multi-paradigma, non possiede una libreria di binding automatici per GTK scritta in
OCaml, ma una libreria scritta in Haskell chiamata ocaml-gi-gtk e sviluppata all’interno
dell’Università di Bologna.
Questo progetto ha lo scopo di convertire in OCaml questa libreria, in modo che possa
essere addottata dalla community del linguaggio. È spesso infatti presente una sorta di
tendenza all’autarchia nel mondo dei linguaggi di programmazione, che rende riluttanti
gli utilizzatori di un linguaggio nei confronti di uno simile e "concorrente"
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Bojanic, Dragana Dee. "Identification of novel functions for the ATP binding cassette transporters GI and G4 during development and ageing." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1905636841&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Dudi-Venkata, Nagendra Naidu. "The Role of Laxatives in Improving Recovery of Gastrointestinal Function after Colorectal Surgery." Thesis, 2021. https://hdl.handle.net/2440/134166.
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Postoperative ileus (POI) is characterised by impairment of bowel motility leading to a delayed return of gastrointestinal (GI) function. It is a common complication after major abdominal surgery, and its clinical features include nausea, vomiting, abdominal distension, and delayed passage of flatus and stool. It predisposes patients to malnutrition, wound failure, and pneumonia, and often requires invasive interventions that significantly impact patient recovery and experience. The occurrence of POI is one of the most important determinants of adverse patient outcome after surgery, often surpassing both preoperative comorbid risk profile and intraoperative factors in the magnitude of its effect on short and long term survival. Delayed return of GI function as a single complication has the largest overall impact on healthcare costs. We do not have cost figures for Australia, but the estimated annual cost in the United States of this complication is approximately $1.5 billion. POI or delayed return of gastro-intestinal function is not a normal or routine part of recovery after abdominal surgery. It arises in around 10-30% of patients and is increasingly regarded as a potentially preventable or treatable problem, the management of which is currently suboptimal. Most published and in-press research on this topic is almost exclusively focused on novel therapeutic medications to treat and prevent ileus. While some of these medications, such as Alvimopan and Prucalopride, may be promising in this regard, they tend to be quite expensive and currently not funded (nor approved) for use in Australia for this indication. There is a major knowledge gap, and significant variability, in the use of readily available “off the shelf” medications and techniques to improve the return of normal GI function. In particular, the use of simple laxatives has been largely overlooked and not subjected to scientific testing despite sporadic worldwide use. This thesis aims to examine the available evidence for laxative use in this clinical setting, document usage patterns in routine clinical practice, and establish their clinical effectiveness and safety profile. A five-step process was adopted to answer these questions. Firstly, a systematic scoping review of Enhanced Recovery After Surgery (ERAS) protocols used in colorectal surgery worldwide was conducted. Second, a systematic review of randomised trials evaluating the safety and efficacy of laxative use after major abdominal surgery was conducted. Third, a global survey to gauge surgeons’ preferences and practice regarding laxative use was undertaken to understand the reasons behind the varied uptake rates of these medications in routine clinical practice. Fourth, a retrospective cohort study was conducted in the colorectal unit at the Royal Adelaide Hospital (RAH), to document the safety and efficacy profile of laxative use in these patients. Finally, an open label randomised controlled trial (RCT) of the combination of simple stimulant and osmotic laxatives to reduce the duration of postoperative Ileus (POI) in patient’s undergoing colorectal surgery (STIMULAX trial) was conducted. Our research found that ERAS protocols commonly recommended laxatives as an intervention targeting POI and return of GI function, but the type and dose were inconsistent, and the evidence quoted was limited. The systematic review of RCT data revealed that while laxative use may result in an earlier passage of a stool after major abdominal surgery, it did not influence other postoperative recovery parameters. There was insufficient data to evaluate the safety profile of laxatives in this setting. Furthermore, this lack of high-quality evidence appeared to be the main reason why most surgeons do not routinely prescribe laxatives after elective colorectal surgery, as shown by the global survey we conducted. This survey also showed that there is wide variability in the type of laxatives used amongst those surgeons who do use laxatives. We then conducted an RCT on the risk-benefit of laxative use after elective colorectal surgery (STIMIULAX trial) to address the knowledge gap. The trial showed that patients receiving multimodal laxatives achieved earlier recovery of GI function after surgery, compared with a control group. There was no difference in major complications, length of stay, or any other key recovery parameters. This paved the way for our final Phase II study (PyRiCo-P). We investigated whether we could safely circumvent the autonomic dysfunction caused after surgery by administering oral Pyridostigmine to reduce the duration of postoperative Ileus after colorectal surgery. Fifteen patients were recruited, and none of the patients had any adverse events. We suggest the next step is to conduct a double-blinded randomised controlled trial to assess the efficacy of Pyridostigmine in this setting. This thesis contributes new evidence on therapeutic effectiveness of laxatives to reduce the duration of ileus after major abdominal surgery and has established a baseline framework upon which future trials of novel medications can be assessed.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2021
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Mbong, Nathan. "Hydrogen peroxide enhances the expression and function of Giα proteins in aortic vascular smooth muscle cells from Sprague-Dawley rats : role of growth factor receptors transactivation." Thèse, 2010. http://hdl.handle.net/1866/12757.
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Nous avons récemment démontré que les espèces réactives oxygénées induisent une augmentation de l’expression des protéines Giα dans les cellules du muscle lisse vasculaire (CMLV) provenant d’aortes de rats spontanément hypertendus (SHR, de l’anglais spontaneously hypertensive rats). La présente étude a pour but d’étudier les effets du peroxyde d’hydrogène (H2O2), un oxydant qui induit le stress oxydatif, sur l’expression de Giα et sur l’activité de l’adénylate cyclase, et d’explorer les voies de signalisation sous-jacentes responsables de cette réponse.
Nos résultats montrent que H2O2 induit une augmentation de l’expression des protéines Giα-2 et Giα-3 de manière dose- et temps-dépendante avec une augmentation maximale de 40-50% à 100 µM après 1 heure, sans affecter l’expression de Gsα. L’expression des protéines Giα a été maintenue au niveau normal en presence de AG 1478, AG1295, PD98059 et la wortmannine, des inhibiteurs d’EGF-R (de l’anglais epidermal growth factor receptor), PDGFR-β (de l’anglais platelet-derived growth factor receptor β), de la voie de signalisation ras-ERK1/2 (de l’anglais extracellular regulated kinase1/2), et de la voie de la PI3Kinase-AKT (de l’anglais phosphatidyl inositol-3 kinase), respectivement. En outre, le traitement des CMLV avec H2O2 a induit une augmentation du degré de phosphorylation d’EGF-R, PDGF-R, ERK1/2 et AKT; et cette expression a été maintenue au niveau témoin par leurs inhibiteurs respectifs. Les inhibiteurs d’EGF-R et PDGF-R ont aussi induit une diminution du degré de phosphorylation de ERK1/2, et AKT/PKB. En outre, la transfection des cellules avec le siRNA (de l’anglais, small interfering ribonucleic acid) de EGF-R et PDGFR-β a atténué la surexpression des protéines Giα-2 et Giα-3 induite par le traitement au H2O2.
La surexpression des protéines Giα induite par H2O2 a été corrélée avec une augmentation de la fonction de la protéine Giα. L’inhibition de l’activité de l’adénylate cyclase par de faibles concentrations de GTPγS après stimulation par la forskoline a augmenté de 20% dans les cellules traitées au H2O2. En outre, le traitement des CMLV au H2O2 a aussi accru l’inhibition de l’activité de l’adénylate cyclase par les hormones inhibitrices telles que l’angiotensine II, oxotrémorine et C-ANP4-23. D’autre part, la stimulation de l’adénylate cyclase induite par GTPγS, glucagon, isoprotérénol, forskoline, et le fluorure de sodium (NaF) a été atténuée de façon significative dans les cellules traitées au H2O2. Ces résultats suggèrent que H2O2 induit la surexpression des protéines Giα-2 and Giα-3 via la transactivation des récepteurs des facteurs de croissance EGF-R, PDGFR-β et l’activation des voies de signalisation ras-ERK1/2 et PI3K-AKT
Mot-cles: Protéines Giα, peroxyde d’hydrogène, stress oxydant, récepteurs des facteurs de croissance, MAP kinases, adénylate cyclase, hypertensionWe recently have shown that reactive oxygen species contribute to the enhanced expression of Giα proteins in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR). The present study was undertaken to examine if H2O2, an oxidant that induces oxidative stress could also enhance the expression of Giα proteins and associated adenylyl cyclase signalling in aortic VSMC and to further explore the underlying signaling pathways responsible for this response. Treatment of cells with H2O2 increased the expression of Giα-2 and Giα-3 proteins but not that of Gsα proteins in a concentration- and time-dependent manner. A maximal increase of 40-50% was observed at 100µM and 1h. The enhanced expression of Giα proteins was restored to control levels by AG 1478, AG1295, PD98059 and wortmannin, inhibitors of epidermal growth factor receptor (EGF-R), platelet-derived growth factor receptor (PDGFR-β), the mitogen-activated protein kinase (MEK1/2), and PI3 kinase respectively. In addition, treatment of VSMC with H2O2 also increased the phosphorylation of EGF-R, PDGF-R, ERK1/2 and AKT and this increased phosphorylation was attenuated to control levels by the respective inhibitors, whereas the inhibitors of EGF-R and PDGE-R also attenuated the enhanced phosphorylation of ERK1/2 and AKT to control levels. Transfection of cells with EGF-R and PDGFR-β siRNA followed by H2O2 treatment restored the H2O2-induced enhanced expression of Giα-2 and Giα-3 proteins to control levels. The increased expression of Giα proteins by H2O2 was reflected in the increased Gi functions. The inhibition of forskolin (FSK)-stimulated AC activity by low concentration of GTPγS (receptor- independent Gi functions) was increased by about 20% by H2O2 treatment. Moreover, treatment of cells with H2O2 also resulted in an increased Ang II-, C-ANP4-23, and oxotremorine-mediated inhibition of AC (receptor-dependent functions of Gi). On the other hand, Gsα-mediated stimulation of AC by GTPγS, glucagon, isoproterenol, FSK, and NaF was significantly decreased in H2O2-treated cells. These results suggest that H2O2 increases the expression of Giα-2 and Giα-3 proteins in VSMC through the transactivation of EGF-R, PDGFR-β and associated ERK1/2 and PI3K signalling pathways. Keywords: Giα proteins, hydrogen peroxide, adenylyl cyclase, oxidative stress, MAP kinase, growth factor receptors, hypertension.
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Lin, Cheng-Jui, and 林承叡. "The effects of GI-related protein-bound uremic toxins on endothelial progenitor cell function and clinical outcomes in chronic kidney disease." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/7z7437.
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博士國立臺北科技大學
工程科技研究所
102
Cardiovascular diseases (CVD) are still the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). Development of accelerated atherosclerosis involves multiple risk factors. However, traditional risk factors could not fully account for the high risk of CVD in CKD patients. Recent studies supported the idea of non-traditional risk factors, which included renal anemia, oxidative stress and uremic toxins. Protein-bound uremic toxins including indoxyl sulfate (IS) and p-cresyl sulfate (PCS) accumulated while renal function decline have been reported having adverse effect on endothelial cells (ECs) function by increasing production of oxidative stress and free radical. Endothelial dysfunction has been regarded to be the essential step resulting in CVD. However, recent studies also showed endothelial progenitor cells (EPCs) could function to restore the endothelial function damaged during coronary ischemia. It is still unclear whether IS or PCS will lead to EPCs dysfunction. Thus, our purpose is to further investigate the pathological effects of IS and PCS from in vitro to in vivo study. Our results showed that IS had obvious negative effect on angiogenesis of human umbilical vein endothelial cells (HUVECs) and EPCs. The ability of EPCs migration, colony forming unit and proliferation were also inhibited by IS and PCS in a dose dependent manner. In addition, we also found the human endothelial function evaluated by flow mediate dilation (FMD) was significantly decreased in advanced CKD. The FMD value was negatively correlated to serum IS and PCS levels after adjusting other confounding factors. Moreover, we also explore the effects of IS and PCS on multiple clinical outcomes in CKD. Form our research, it showed IS and PCS were capable of predicting CVD event and kidney function deterioration in patients with CKD stage 3-5. For hemodialysis patients, PCS was strongly associated with CVD event, hospitalization event and vascular access failure. Both toxins were also a valuable surrogate to evaluate the event of CVD, mortality and peritoneal dialysis (PD) failure in PD cohort. From our results above-mentioned, it indicated that higher serum IS and PCS levels were closely related to worse clinical outcomes. We speculate that these adverse outcomes may contribute directly or indirectly to the loss of endothelial cell function owing to inhibition of EPCs function by IS or PCS.
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Shen, Tzu-Yi, and 沈姿儀. "Characterization and Functional Analysis ofGIGANTEA (GI) Orthologues from Arabidopsis andFerns Reveals the Possibly Functional Diversity fortheir C- and N-terminal Portion." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/66be7u.
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碩士國立中興大學
生物科技學研究所
101
GIGANTEA (GI) has been considered to be involved in circadian clock pathway to regulate the flowering in plants. Mutation in GI delays the flowering time and increases the tolerance to oxidative stress in the Arabidopsis thaliana. To further investigate the multiple functions for GI, GI orthologues (PcGI and AcGI) were cloned from non-flowering ferns Adiantum capillus-veneris L. and Pteris cretica cv. Albolineata. The expression of fern’s GIs also showed a circadian rhythm with the highest expression at 8 to 12 h of the light period and the lowest expression at dawn. A partial rescue of late flowering phenotype by activating CONSTANS (CO), FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS (SOC1) was observed in the gi mutant of Arabidopsis ectopically expressed fern’s GIs. This implied the function of GI genes is conserved in flowering and non-flowering plants. Ectopic expression of PcAt-GI which contains the N-terminal of PcGI and C-terminal of AtGI could rescue the late-flowering of gi mutants stronger than AtPc-GI which contains the N-terminal of AtGI and C-terminal of PcGI. Furthermore, ectopic expression of C-terminal portion of GI, PcGI or AcGI promotes flowering in the Arabidopsis gi-1 and gi-2 mutants. By contrast, the N-terminal portion of these three GI orthologues could only weakly promote flowering in gi-1 and gi-2 mutants. These results revealed that the C-terminus of the GI protein is functionally more important in flowering than the N-terminus. Besides flowering time, additional male sterility of the flower due to anther indehiscence was only observed in 35S::AtGI and 35S::AtPc-GI plants. Futher analysis indicated that secondary thickening was absent in the endothecium of anther in 35S::AtGI and 35S::AtPc-GI transgenic Arabidopsis due to the down-regulation of NST1, NST2 and MYB85. Our result implied that the N-terminus of the AtGI contained the function in regulating the anther development once ectopic expressing in Arabidopsis.
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Li, Ya-Chun, and 黎雅君. "Functional Analysis of GIGANTEA(GI) and Its Interacting Proteins in Regulating Flowering Time and Leaf Senescence in Arabidopsis thaliana." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/59569180449887546153.
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碩士國立中興大學
生物科技學研究所
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Mutation in GI caused delayed flowering, high tolerance to paraquat -induced oxidative stress, high resistance to cold stress and delayed leaf senescence. These results reveal that GI should play multiple roles during plant development. To further investigate the different mechanisms regulated by GI, yeast-two hybrid was performed to identify its interacting proteins. Two proteins encoded are a chlorophyll A/B binding protein 4 precursor and an unknown functional gene (At3g51140) which showed strong interaction with GI protein. Further analysis identified an ankyrin repeat family protein (AFT) that interacted with chlorophyll A/B binding protein 4 precursor. A vesicle-associated membrane protein, NAC2 and a stress-inducible protein (At1g62740) that interacted with the unknown functional protein (At3g51140). Functional analyses of genes encoding those proteins are in progress. Furthermore, to investigate the different portions of the GI protein responsible for various function, constructs containing different truncated forms of GI protein were generated and transformed into wild-type and gi mutants for functional analysis. Further analyses of the transgenic plants transformed with these truncated forms of GI protein is in progress. The results obtained should lead a deeper understanding of the function of GI gene in regulating plant development.
Books on the topic "GI function"
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Hongō, Michio, editor of compilation, ed. Functional and GI motility disorders. Basel: Karger, 2014.
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Keshav, Satish, and Alexandra Kent. Normal gastrointestinal function. Edited by Patrick Davey and David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0193.
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The gastrointestinal (GI) system accomplishes the tasks of digestion, absorption of nutritional compounds, and removal of waste products. This is a complex process, involving the hollow GI tract and the hepatic, pancreatic, and biliary systems. Symptoms and signs of disease relate directly to the digestive and/or absorptive processes they interrupt. This chapter discusses normal GI function, following the progress of food through the GI tract. It starts with a brief introduction, which is followed by a section on the action of swallowing. It then discusses the anatomy and function of the oesophagus, the stomach, the duodenum, the jejunum, the ileum, the pancreas, the biliary tree, the colon, the rectum, and the anus.
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GOMEZ, SHARON PEIRCE. Patients Who Need Help With Gi Function 6 Disk Set. Lippincott Williams & Wilkins, 1995.
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Blaser, Annika Reintam, and Adam M. Deane. Normal physiology of the gastrointestinal system. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0172.
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The gastrointestinal (GI) system is responsible for digestion and absorption, but also has important endocrine, immune and barrier functions. Additionally, the GI system plays a major role in fluid, electrolyte and acid-base balance. The GI system is regulated by complex myogenic, neural and humoral mechanisms, and, in health, these are affected by the presence of luminal nutrient, thereby modulating function of the GI system. Accordingly, GI function varies depending on whether a person is fasted or in the postprandial state. Adequate fasting and postprandial perfusion, motility and exocrine secretion are required for ‘normal’ functioning. The protective mechanisms of the GI system consist of physical (intact gut mucosa), non-immune (gastric acid, intestinal mucin, bile and peristalsis) and immune (gut-associated lymphoid tissue, GALT) elements. Disruption of GI protection is a putative mechanism underlying the development of multiple-organ dysfunction syndrome. Maintenance of GI function is increasingly recognised as an important factor underlying survival in critical illness.
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Function of receptor tyrosine kinases in Gi-deficient cells: Preferential suppression of insulin signalling. Ottawa: National Library of Canada, 2000.
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Rogler, Gerhard. Gastrointestinal system. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199642489.003.0021.
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Rheumatic diseases and diseases of the gastrointestinal (GI) tract are connected in two ways. The extraintestinal manifestations of inflammatory GI diseases such as inflammatory bowel disease affect joints in up to one-third of patients. On the other hand, several rheumatic diseases such as vasculitis or systemic lupus erythematosus (SLE) induce a wide spectrum of gastrointestinal manifestations. The GI tract constitutes a huge area in contact with the environment. It is exposed to billions of food antigens, commensal bacteria, and potential pathogens. Some of those antigens are thought to play a role in the pathogenesis of rheumatic diseases. The intestinal barrier function and the gut immune system are tightly regulated, as on one hand tolerance for food antigens and the resident commensal flora needs to be maintained, and on the other hand pathogens need to be rapidly and effectively eliminated. Non-infectious, chronic inflammatory diseases of the small and large intestine with rheumatic manifestations have been well known for decades. Among the susceptibility genes for Crohn's disease and ulcerative colitis are some that also cause susceptibility to rheumatoid arthritis or SLE, indicating a shared susceptibility and overlapping pathological mechanisms. Subsequently, similar therapeutic principles have successfully been applied in autoimmune GI and rheumatological diseases such as steroids, immunosuppressants, and anti-TNF (tumour necrosis factor) antibodies.
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Quigley, E. M. M., M. Hongo, and S. Fukudo, eds. Functional and GI Motility Disorders. S. Karger AG, 2014. http://dx.doi.org/10.1159/isbn.978-3-318-02579-8.
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Waldmann, Carl, Neil Soni, and Andrew Rhodes. Neurological drugs. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199229581.003.0013.
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Opioid and non-opioid analgesics in the ICU 206Sedation management in ICU 208Muscle relaxants 210Anticonvulsant drugs 212Cerebroprotective agents 214Mannitol and hypertonic saline 216Opioid analgesic drugs remain the mainstay of pain relief in the Critical Care Unit. Abnormal GI function in the critically sick consequently makes enteral administration undesirable. IV administration remains the mainstay. Pharmacokinetic considerations consequent upon organ dysfunction leading to altered absorption, distribution and metabolism usually play the most important role in the choice of agent....
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Keshav, Satish, and Alexandra Kent. Psychiatry in gastrointestinal medicine. Edited by Patrick Davey and David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0206.
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This chapter discusses psychiatric conditions with gastrointestinal (GI) consequences (including eating disorders, depression, and side effects of psychiatric medications), and GI diseases with psychiatric symptoms (including hepatic encephalopathy, coeliac disease, Wilson’s disease, acute intermittent porphyria, functional GI disease, and inflammatory bowel disease).
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Rosh, Joel R., Leo A. Heitlinger, and Walter D. Rosenfeld, eds. AM:STARs: Clinical GI Challenges in the Adolescent, Vol. 27, No. 1. American Academy of Pediatrics, 2016. http://dx.doi.org/10.1542/9781581109382.
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It is now recognized that the prevalence of atopic disorders including (EoE) and immune based conditions such as celiac disease and inflammatory bowel disease are on the rise. This changing epidemiology coupled with advancements in the diagnosis of these conditions have led to greater numbers of adolescents needing treatment. Topics include: Swallowing disorders and eosinophilic esophagitis Celiac and gluten-related disorders Functional GI disorders Advances in inflammatory bowel disease Advances in hepatology Obesity Fad diets, FODMAPS Vitamin D and bone health Gut microbiome and probiotics GI issues in adolescents with eating disorders Health maintenance in adolescents with chronic GI disorders Transition of care
Book chapters on the topic "GI function"
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Nakamura, Futoshi. "Concept and Application of Green and Hybrid Infrastructure." In Ecological Research Monographs, 11–30. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6791-6_2.
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AbstractRecently, Japan has suffered extraordinary damage from typhoons, heavy rains, and megafloods, each of which has exceeded the upper limit of control by managed infrastructure for flood mitigation. First, I present a conceptual framework of hybrid infrastructure at the watershed scale, combining (1) fundamental green infrastructure (GI), composed of forests and wetlands in the watershed; (2) additional multilevel GI, such as flood control basins; and (3) existing engineered disaster prevention infrastructure, such as dams and artificial levees. Second, I introduce the disaster risk reduction function of natural forests and wetlands and three representative traditional flood control measures: discontinuous levees, overflow embankments, and flood protection forests. This GI should be properly allocated and maintained at the watershed scale to reduce damage by megafloods. The multiple types and functions of GI may provide essential habitats for wildlife and recreational opportunities for local residents and others. Finally, I address key points for planning, implementation, and governance of GI at the watershed scale.
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Nakamura, Futoshi. "Introduction." In Ecological Research Monographs, 1–7. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6791-6_1.
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AbstractWorldwide, Green Infrastructure (GI) has mainly been discussed from an adaptation strategy perspective in cities and urban areas. However, we believe that GI can also function in rural and suburban areas where depopulation is prominent. From 2015 to 2021, my colleagues and I have launched two projects, titled “Green Infrastructure with a Declining Population and Changing Climate: Assessment of Biodiversity, Disaster Prevention, and Social Values” and “Complementary Role of Green and Gray Infrastructures: Evaluation from Disaster Prevention, Environment, and Social and Economic Benefit,” which were supported by the Environment Research and Technology Development Funds (4-1504 and 4-1805) of the Ministry of the Environment of Japan. This volume introduces some of our achievements in the projects. Additionally, I invited active foreign scientists from the United Kingdom and the United States to contribute their experiences and knowledge to this volume. As suggested by the studies, one of the important characteristics of GI is multifunctionality, which maintains biodiversity and traditional landscapes. Using a natural and seminatural GI network in a watershed, we are able to adapt to elevated disaster risks in a changing climate while sustaining traditional land use and restoring natural ecosystems that provide a suite of ecosystem services and human welfare.
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Morimoto, Junko, Susumu Goto, Akito Kuroyanagi, Motoko Toyoshima, and Yuichiro Shida. "Natural Succession of Wetland Vegetation in a Flood-Control Pond Constructed on Abandoned Farmland." In Ecological Research Monographs, 209–24. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6791-6_13.
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AbstractCan a flood-control basin be considered a component of green infrastructure (GI) with not only disaster prevention functions but also biodiversity conservation functions? We studied the succession of wetland vegetation in a flood-control basin constructed in a floodplain. The number of species composing the buried seeds depended on the depth of the soil layer, with shallower (recent) layers having more species. Plants germinated from buried seeds in deep (ancient) soil layers were small and difficult to identify based on morphology alone, but DNA-based analyses made it possible to identify these species. The occurrence of three species of Juncus and Cyperus in the peat layer that developed between 840 and 1215 years ago indicates that it is possible to regenerate wetland plants from the past if the buried seeds are well preserved and in good condition. The excavated section of the experimental site, which was set in part of the flood-control basin, received dispersed seeds from the surrounding agricultural land and contained more species than did the soil layer itself. The shallower the water depth was (the shallower the excavation depth), the greater the number of species that occurred. In addition, species with different life forms occurred depending on the water depth. More species occurred in the entire flood-control basin than in the experimental site. The factors that determined the type of plant community were years since excavation, water depth, and water quality. Finally, we discussed the management practices concerning the supply of propagules and the management of suitable habitats as essential factors for flood-control basins constructed on fallow land to function as GI.
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Tack, Jan, and Sébastien Kindt. "GI Immune Response in Functional GI Disorders." In Frontiers of Gastrointestinal Research, 118–25. Basel: KARGER, 2009. http://dx.doi.org/10.1159/000258287.
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Ishiyama, Nobuo, Satoshi Yamanaka, Keita Ooue, Masayuki Senzaki, Munehiro Kitazawa, Junko Morimoto, and Futoshi Nakamura. "Flood-Control Basins as Green Infrastructures: Flood-Risk Reduction, Biodiversity Conservation, and Sustainable Management in Japan." In Ecological Research Monographs, 189–207. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6791-6_12.
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AbstractGreen infrastructure (GI) is a strategic planning infrastructure that uses the functions of ecosystems. Under an increased river flood risk, flood-risk management utilizing GI is gaining attention from managers and ecologists in Japan. Flood-control basins are facilities that temporarily store river water in adjacent reservoirs to mitigate flood peaks and gradually drain the water back to the main channels after a flood. GI is expected to provide multiple functions, such as flood-risk reduction and habitat provisions. However, there are limited studies on the ecological functions of flood-control basins. In this article, we first introduce the characteristics of flood-control basins constructed in Japan. Next, we show the ecological importance of flood-control basins in terms of wetland organism biodiversity conservation. Finally, to aid the integration of GI into conventional flood-control measures, we highlight ecological and social issues about introducing and managing flood-control basins.
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Cassiday, Karen Lynn. "Exposure Therapy for Functional GI Disorders." In Using Central Neuromodulators and Psychological Therapies to Manage Patients with Disorders of Gut-Brain Interaction, 143–74. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-18218-2_6.
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Gamboa, Heidi E., and Manu R. Sood. "The Spectrum of Functional GI Disorders." In Textbook of Pediatric Gastroenterology, Hepatology and Nutrition, 255–64. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-80068-0_19.
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Parnas, David Lorge. "Functional Specifications for Old (and New) Software." In GI - 20. Jahrestagung I, 3–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76118-8_1.
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Rainsford, K. D. "Introduction: Advances in the Biochemical Pharmacology of Gastrointestinal (GI) Functions as an Approach to Understanding GI Disorders." In Biochemical Pharmacology as an Approach to Gastrointestinal Disorders, 1–4. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5390-4_1.
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Giachetti, A., E. Monferini, A. Schiavone, R. Micheletti, R. Hammer, and H. Ladinsky. "Functional and Biochemical Evidence for Muscarinic Receptor Subtypes in the Gastrointestinal Tract." In Muscarinic Receptor Subtypes in the GI Tract, 14–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-70668-4_2.
Full textConference papers on the topic "GI function"
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Gonzalez-Perez, Ignacio, Alfonso Fuentes, Faydor L. Litvin, and Kenichi Hayasaka. "Computerized Design of Muti-Gear Drives for Function Generation." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86252.
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A new approach for generation of functions based on application of a multi-gear drive is proposed. The approach provides solution to the functional Ψ(α) = gn(gn−1(⋯(g1(α)))) wherein Ψ(α) is the function assigned for generation and gi(α), i = 1,⋯,n, is the transmission function of pair i of conjugated non-circular gears. The specifics characteristics of the proposed approach are: (a) integrated impact by application of n synchronized gear drives, (b) favourable shape of centrodes, and (c) observation of limits of pressure angle. The developed theory is illustrated with several detailed numerical examples.
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Li, Hongyan, Herman Kucharavy, Carla Hajj, Guoqiang Hua, Ryan Glass, Zhaoshi Zeng, Zvi Fuks, et al. "Abstract 3347: Radiation-induced gastrointestinal (GI) syndrome as a function of age." In Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-3347.
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Fields, Aaron J., Susan M. Millard, Jeannie F. Bailey, Dylan O’Carroll, Jeffrey C. Lotz, and Robert A. Nissenson. "Bone Biomechanical Behavior in Adult Mice is Regulated by Osteoblast Gi Signaling in a Sex- and Site-Specific Manner." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53773.
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Osteoporosis decreases bone strength owing to loss of bone mass and deterioration in bone microstructure. The maintenance of bone mass and microstructure depends, at least in part, on the signaling and function of osteoblasts. For example, Gi-coupled signaling by G-protein coupled receptors endogenous to osteoblasts has been shown to restrict cortical and trabecular bone formation in female mice [1,2]. This suggests that inhibiting Gi-coupled signaling in osteoblasts may be an effective strategy for the development of anabolic osteoporosis therapies. However, it remains unclear whether inhibiting Gi-coupled signaling improves bone biomechanical behavior. Thus, the objectives of this study were to: 1) quantify the effect of Gi-coupled signaling on bone strength and bone stiffness; and 2) determine the effects of this signaling mechanism on cortical and trabecular microstructure and on the relationship between mechanical behavior and microstructure.
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Cipolla, Russell C., and Darrell R. Lee. "Technical Basis for Equations for Stress Intensity Factor Coefficients in ASME Section XI Appendix A." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2708.
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The stress intensity factor (KI) equations in ASME Section XI, Appendix A are based on non-dimensional coefficients (Gi) that allow for the calculation of stress intensity factors for a cubic varying stress field for a surface crack, and linear varying stress field for a sub-surface crack. Currently, the coefficients are in tabular format for the case of a surface crack in a flat plate geometry. For the buried elliptical flaw, the Gi coefficients are in graphical format. The tabular/graphical form makes the computation of KI tedious when determination of KI for various crack sizes is pursued. In this paper, closed-form equations are developed based on a weight function representation for the KI solutions for a surface crack. These equations permit the calculation of the Gi coefficients without the need to perform tabular interpolation within the current tables in Article 3320 of Appendix A. The equations are complete up to a fourth order polynomial representation of applied stress, so that the procedures in Appendix A have been expanded. The fourth-order representation for stress will allow for more accurate fitting of highly non-linear stress distributions, such as those depicting high thermal gradients and weld residual stress fields. It is expected that the equations developed in this paper will be added to the Appendix A procedures. With the inclusion of equations to represent Gi, the procedures of Appendix A for the determination of KI can be performed more efficiently. This is especially useful in performing flaw growth calculations where repetitive calculations are required in the computations of crack size versus time. The equations are relatively simple in format so that the KI computations can be performed by either spreadsheet analysis or by simple computer programming languages. The format of the equations is generic in that KI solutions for other geometries can be added to Appendix A relatively easily.
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Sinningen, Kathrin, Alina Drozdowska, Michael Falkenstein, Thomas Lücke, and Mathilde Kersting. "P 235. Short-Term Effects of Lunch with Varying Glycemic Index on Children’s Cognitive Function—CogniDo GI-II." In Abstracts of the 44th Annual Meeting of the Society for Neuropediatrics. Georg Thieme Verlag KG, 2018. http://dx.doi.org/10.1055/s-0038-1676010.
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Sun, Zixiang, Nicholas J. Hills, and Richard Scott. "A CFD Assessment of Engine Core Zone Casing Heat Transfer." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90381.
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Abstract A systematic CFD investigation was conducted to assess the core zone (CZ) casing heat transfer of a large civil aircraft engine. Three key engine operating conditions, maximum takeoff (MTO), cruise (CRZ) and ground idle (GI) were analyzed. Steady flows were assumed. Turbulence was simulated using the realizable k-epsilon model in conjunction with the scalable wall function. Buoyancy effect was taken into account. Radiation was calculated using the discrete ordinate (DO) model. It was shown that the forced convection heat transfer dominates in most of the casing surface in the core zone, and radiation is of second importance in general. However, in some areas where both convection and radiation heat transfer are weak but the latter is relatively greater in magnitude than the former, radiation heat transfer could thus become dominant. In addition, the overall impact of radiation on casing heat transfer increases from MTO to CRZ and GI conditions, as the strength of engine load decreases. The overall effect of buoyancy on casing heat transfer is small, but could be noticeable in some local areas where flow velocity is low. The insight into heat transfer features on the engine core zone casing supported by quantified CFD evidences is the first in the public domain, as far as authors are aware.
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Wang, Rubin, and Kimihiko Yasuda. "Exact Stationary Response Solutions of Nine Classes of Nonlinear Stochastic Systems Under Stochastic Parametric and External Excitations." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/vib-8096.
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Abstract In this paper, a systematic procedure is developed to obtain the stationary probability density function for the response of a general nonlinear system under parametric and external Gaussian white noise excitations. In reference [15], nonlinear function of system was expressed to the polynomial formula. The nonlinear system described here has the following form: x¨+g(x,x˙)=k1ξ1(t)+k2xξ2(t), where g(x,x˙)=∑i=0∞gi(x)x˙i and ξ1,ξ2 are Gaussian white noises. Thus, this paper is a generalization for the results studied in reference [15]. The reduced Fokker-Planck (FP) equation is employed to get the governing equation of the probability density function. Based on this procedure, the exact stationary probability densities of many nonlinear stochastic systems are obtained, and it is shown that some of the exact stationary solutions described in the literature are only particular cases of the presented generalized results.
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Cipolla, Russell C., and Darrell R. Lee. "Closed Form Solutions for Stress Intensity Factor Coefficients for Circumferential ID Surface Flaws in Cylinders in ASME Section XI Appendix A." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78187.
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The stress intensity factor (KI) equations for a surface crack in ASME Section XI, Appendix A are based on non-dimensional coefficients (Gi) that allow for the calculation of stress intensity factors for a cubic varying stress field. Currently, the coefficients are in tabular format for the case of a surface crack in a flat plate geometry. The tabular form makes the computation of KI tedious when determination of KI for various crack sizes is pursued and a flat plate geometry is conservative when applied to a cylindrical geometry. In this paper, closed-form equations are developed based on tabular data from API 579 (2007 Edition) [1] for circumferential cracks on the ID surface of cylinders. The closed-form equations provide G0 and G1 coefficients while G2 through G4 are obtained using a weight function representation for the KI solutions for a surface crack. These equations permit the calculation of the Gi coefficients without the need to perform tabular interpolation. The equations are complete up to a fourth order polynomial representation of applied stress, so that the procedures in Appendix A have been expanded. The fourth-order representation for stress will allow for more accurate fitting of highly non-linear stress distributions, such as those depicting high thermal gradients and weld residual stress fields. It is expected that the equations developed in this paper will be added to the Appendix A procedures. With the inclusion of equations to represent Gi, the procedures of Appendix A for the determination of KI can be performed more efficiently without the conservatism of using flat plate solutions. This is especially useful in performing flaw growth calculations where repetitive calculations are required in the computations of crack size versus time. The equations are relatively simple in format so that the KI computations can be performed by either spreadsheet analysis or by simple computer programming. The format of the equations is generic in that KI solutions for other geometries can be added to Appendix A relatively easily.
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Lee, Darrell R., Russell C. Cipolla, and Michael C. Liu. "Stress Intensity Factor Coefficients for Circumferential OD Surface Flaws in Cylinders for Appendix A of ASME Section XI." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84381.
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Linear elastic fracture mechanics based flaw evaluation procedures in Section XI of the ASME Boiler and Pressure Vessel Code require calculation of the stress intensity factor (KI). The 2015 Edition of ASME Section XI [1] implemented a number of significant improvements in Article A-3000, including closed-form equations for calculating stress intensity factor influence coefficients (Gi) for circumferential flaws on the inside surface of cylinders. In the 2017 Edition [2], closed-form equations for axial flaws on the inside and outside surfaces of cylinders have been implemented. In this paper, closed-form equations are developed for circumferential cracks on the OD surface of cylinders, based on tabular data from API 579 (2007 Edition) [3]. The equations presented, represent a complete set of Ri/t, a/t, and a/ℓ ratios. The closed-form equations provide G0 and G1 coefficients while G2 through G4 are obtained using a weight function representation for the KI solutions for a surface crack. These equations permit the calculation of the Gi coefficients without the need to perform tabular interpolation. The equations are complete up to a fourth order polynomial representation of the applied stress. The fourth-order representation for stress will allow for more accurate fitting of highly non-linear stress distributions, such as those depicting high thermal gradients and weld residual stress fields.
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Cipolla, Russell C., and Darrell R. Lee. "Stress Intensity Factor Coefficients for Circumferential ID Surface Flaws in Cylinders for Appendix A of ASME Section XI." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97734.
Full textAbstract:
The stress intensity factor (KI) equations for a surface crack in ASME Section XI, Appendix A are based on non-dimensional coefficients (Gi) that allow for the calculation of stress intensity factors for a cubic varying stress field. Currently, the coefficients are in tabular format for the case of a surface crack in a flat plate geometry. The tabular form makes the computation of KI tedious when determination of KI for various crack sizes is required and a flat plate geometry is conservative when applied to a cylindrical geometry. In this paper, closed-form equations are developed based on tabular data from API 579 (2007 Edition) [1] for circumferential cracks on the ID surface of cylinders. The equations presented, represent a complete set of Ri/t, a/t, and a/l ratios and include those presented in the 2012 PVP paper [8]. The closed-form equations provide G0 and G1 coefficients while G2 through G4 are obtained using a weight function representation for the KI solutions for a surface crack. These equations permit the calculation of the Gi coefficients without the need to perform tabular interpolation. The equations are complete up to a fourth order polynomial representation of applied stress, so that the procedures in Appendix A have been expanded. The fourth-order representation for stress will allow for more accurate fitting of highly non-linear stress distributions, such as those depicting high thermal gradients and weld residual stress fields. The equations developed in this paper will be added to the Appendix A procedures in the next major revision to ASME Section XI. With the inclusion of equations to represent Gi, the procedures of Appendix A for the determination of KI can be performed more efficiently without the conservatism of using flat plate solutions. This is especially useful when performing flaw growth evaluations where repetitive calculations are required in the computations of crack size versus time. The equations are relatively simple in format so that the KI computations can be performed by either spreadsheet analysis or by simple computer programming. The format of the equations is generic in that KI solutions for other geometries can be added to Appendix A relatively easily.
Reports on the topic "GI function"
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Dudley, Lynn M., Uri Shani, and Moshe Shenker. Modeling Plant Response to Deficit Irrigation with Saline Water: Separating the Effects of Water and Salt Stress in the Root Uptake Function. United States Department of Agriculture, March 2003. http://dx.doi.org/10.32747/2003.7586468.bard.
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Standard salinity management theory, derived from blending thermodynamic and semi- empirical considerations leads to an erroneous perception regarding compensative interaction among salinity stress factors. The current approach treats matric and osmotic components of soil water potential separately and then combines their effects to compute overall response. With deficit water a severe yield decrease is expected under high salinity, yet little or no reduction is predicted for excess irrigation, irrespective of salinity level. Similarly, considerations of competition between chloride and nitrate ions have lead to compensation hypothesis and to application of excess nitrate under saline conditions. The premise of compensative interaction of growth factors behind present practices (that an increase in water application alleviates salinity stress) may result in collateral environmental damage. Over-irrigation resulting in salinization and elevated ground water threatens productivity on a global scale. Other repercussions include excessive application of nitrate to compensate for salinity, unwillingness to practice deficit irrigation with saline water, and under-utilization of marginal water. The objectives for the project were as follows: 1) To develop a database for model parameterization and validation by studying yield and transpiration response to water availability, excessive salinity and salt composition. 2) To modify the root sink terms of an existing mechanism-based model(s) of water flow, transpiration, crop yield, salt transport, and salt chemistry. 3) To develop conceptual and quantitative models of ion uptake that considers the soil solution concentration and composition. 4) To develop a conceptual and quantitative models of effects of NaCl and boron accumulation on yield and transpiration. 5) To add a user interface to the water flow, transpiration, crop yield, salt transport, chemistry model to make it easy for others to use. We conducted experiments in field plots and lysimeters to study biomass production and transpiration of com (Zeamays cv. Jubilee), melon (Cucumismelo subsp. melo cv. Galia), tomato (Lycopersiconesculentum Mill. cv. 5656), onion (Alliumcepa L. cv. HA 944), and date palms (Phoenix Dactylifera L. cv. Medjool) under salinity combined with water or with nitrate (growth promoters) or with boron (growth inhibitor). All factors ranged from levels not limiting to plant function to severe inhibition. For cases of combined salinity with water stress, or excess boron, we observed neither additive nor compensative effects on plant yield and transpiration. In fact, yield and transpiration at each combination of the various factors were primarily controlled by one of them, the most limiting factor to plant activity. We proposed a crop production model of the form Yr = min{gi(xi), where Yr = Yi ym-1 is relative yield,Ym is the maximum yield obtained in each experiment, Xi is an environmental factor, gi is a piecewise-linear response function, Yi is yield of a particular treatment. We selected a piecewise-linear approach because it highlights the irrigation level where the response to one factor ceases and a second factor begins. The production functions generate response "envelopes" containing possible yields with diagonal lines represent response to Xi alone and the lines parallel to the X-axis represent response to salinity alone. A multiplicative model was also derived approximating the limiting behaviour for incorporation in a hydrochemical model. The multiplicative model was selected because the response function was required to be continuous. The hydrochemical model was a better predictor of field-measured water content and salt profiles than models based on an additive and compensative model of crop response to salinity and water stress.
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Weiss, David, and Neil Olszewski. Manipulation of GA Levels and GA Signal Transduction in Anthers to Generate Male Sterility. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7580678.bard.
Full textAbstract:
The original objectives of the research were: i. To study the role of GA in anther development, ii. To manipulate GA and/or GA signal transduction levels in the anthers in order to generate male sterility. iii. To characterize the GA signal transduction repressor, SPY. Previous studies have suggested that gibberellins (GAs) are required for normal anther development. In this work, we studied the role of GA in the regulation of anther development in petunia. When plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to: study GA responses. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development. Spy acts as a negative regulator of gibberellin (GA) action in Arabidopsis. We cloned the petunia Spy homologue, PhSPY, and showed that it can complement the spy-3 mutation in Arabidopsis. Overexpression of Spy in transgenic petunia plants affected various GA-regulated processes, including seed germination, shoot elongation, flower initiation, flower development and the expression of a GA- induced gene, GIP. In addition, anther development was inhibited in the transgenic plants following microsporogenesis. The N-terminus of Spy contains tetratricopeptide repeats (TPR). TPR motifs participate in protein-protein interactions, suggesting that Spy is part of a multiprotein complex. To test this hypothesis, we over-expressed the SPY's TPR region without the catalytic domain in transgenic petunia and generated a dominant- negative Spy mutant. The transgenic seeds were able to germinate on paclobutrazol, suggesting an enhanced GA signal. Overexpression of PhSPY in wild type Arabidopsis did not affect plant stature, morphology or flowering time. Consistent with Spy being an O-GlcNAc transferase (OGT), Spy expressed in insect cells was shown to O-GlcNAc modify itself. Consistent with O-GlcNAc modification playing a role in GA signaling, spy mutants had a reduction in the GlcNAc modification of several proteins. After treatment of the GA deficient, gal mutant, with GA3 the GlcNAc modification of proteins of the same size as those affected in spy mutants exhibited a reduction in GlcNAcylation. GA-induced GlcNAcase may be responsible for this de-GlcNAcylation because, treatment of gal with GA rapidly induced an increase in GlcNAcase activity. Several Arabidopsis proteins that interact with the TPR domain of Spy were identified using yeast two-hybrids screens. One of these proteins was GIGANTEA (GI). Consistent with GI and Spy functioning as a complex in the plant the spy-4 was epistatic to gi. These experiments also demonstrated that, in addition to its role in GA signaling, Spy functions in the light signaling pathways controlling hypocotyl elongation and photoperiodic induction of flowering. A second Arabidopsis OGT, SECRET AGENT (SCA), was discovered. Like SPY, SCA O-GlcNAc modifies itself. Although sca mutants do not exhibit dramatic phenotypes, spy/sca double mutants exhibit male and female gamete and embryo lethality, indicating that Spy and SCA have overlapping functions. These results suggest that O-GlcNAc modification is an essential modification in plants that has a role in multiple signaling pathways.