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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.
41

Thresholds of Hypoxia for Red Sea Corals

Alva Garcia, Jacqueline Victoria 11 1900 (has links)
Over the last four decades, coral reefs have suffered a ~50% decline of across the tropics. Consequently, most research efforts have focused on the impacts of anthropogenic pressures on corals, including ocean warming, ocean acidification, and overfishing. However, recent discoveries indicate that coral reefs are becoming increasingly vulnerable to acute deoxygenation events, which can drive severe and widespread coral bleaching, and in some cases, mortality of corals and other reef organisms. On unimpacted coral reefs, dissolved oxygen (DO) availability can vary between 50% and 200% air saturation, depending on the location, proximity to the open-ocean, and time of the day. During the daytime, Symbiodiniaceae spp. produce more O$_2$ than the coral host can consume, releasing excess O$_2$ to the surrounding tissues. However, at nighttime Symbiodiniaceae spp. cease O$_2$ production. Hence, corals may suffer to O$_2$ deprivation at nighttime when the photosynthesis ceases, and holobiont respiration consumes oxygen. To assess the O$_2$ thresholds and aftereffects of two Red Sea coral species: ${{P. lobata}}$ and ${{G. fascicularis}}$ corals were exposed to reduced DO concentrations. Coral fragments from both species were exposed to one control treatment (6.8 mg O$_2$ l$^{−1}$) and three reduced DO concentrations treatments (5.25 mg O$_2$ l$^{−1}$, 3.5 mg O$_2$ l$^{−1}$, and 1.25 mg O$_2$ l$^{−1}$). Experiments were held at a stable temperature (32°C ± 0.25) and stable pH levels (pH 8.2 ± 0.08). Corals in these experiments displayed different thresholds to low O$_2$ concentrations. ${{P. lobata}}$ coral fragments didn’t exhibit any bleaching symptoms throughout complete experiment. However, ${{G. fascicularis}}$ fragments showed signs of bleaching after the third night of exposure to the low O$_2$ treatment (1.25 mg O$_2$ l$^{−1}$). Physiological variables such as maximum and effective photochemical efficiency, Chl ${{a}}$, cell density, and dark respiration experienced the lowest values under the low O$_2$ treatment for both species. These results highlight the need for further experimental assessments of deoxygenation thresholds for corals across the globe. These assessments are of great importance to create better conservation strategies for the preservation of coral reefs.
42

Modélisation de la plaie chronique : contrôle de la formation de fibres élastiques en conditions hypoxiques / .

Boizot, Jérémy 15 July 2015 (has links)
Pas de résumé / Pas de résumé
43

A descriptive study of suspected perinatal asphyxia at Mitchells Plain District Hospital. A case series

Stofberg, Johannes Petrus Jordaan 16 March 2022 (has links)
Background: South Africa aims to end all preventable deaths of children under the age of five as part of their commitment to the Sustainable Development Goals. More than half of these mortalities occur in the neonatal period with perinatal asphyxia as one of the leading causes. This study investigated and identified the characteristics of perinatal asphyxia and its contributing factors at a district hospital in Cape Town. Methods: A retrospective descriptive case series was performed and included all suspected cases of perinatal asphyxia referred from Mitchells Plain District Hospital (MPH)) to a specialised centre in the years 2016-2018. A data collection tool was used to extract information. Data was processed with SPSS to produce descriptive statistics and to investigate associations between variables using the Chi-square tests. Results: The study included 29 cases of suspected perinatal asphyxia. Ten (34.5%) had abnormal amplitude Electroencephalograms (aEEG's) indicative of Hypoxic Ischaemic Encephalopathy (HIE) and four (13.8%) demised before day seven of life. Non-operative deliveries (p=0.005), lack of a doctor at the time of delivery (p=0.004) and neonatal chest compressions (p=0.044) were associated with abnormal aEEG's. Babies with Thompson score of equal to or more than 12 (p=0.006), neonatal seizures (p=0.036) and delayed arrival at referral hospital (p=0.005) were associated with abnormal aEEG findings. Mortality was associated with Thompson score ≥12 (p=0.007) and the need for neonatal intubation at delivery (p=0.016). Conclusions: Significant reversable factors were identified in the peri-and postpartum periods. More capacitated staff would have the greatest impact on outcomes. The profile of HIE is exceedingly complex and challenges the resources and services of district level of care. Therefore, these factors should be targeted for future development and investment to improve outcomes from district hospitals.
44

Increased Oligodendrogenesis by Humanin Promotes Axonal Remyelination and Neurological Recovery in Hypoxic/Ischemic Brains

Chen, Jing, Sun, Miao, Zhang, Xia, Miao, Zhigang, Chua, Balvin H.L., Hamdy, Ronald C., Zhang, Quan Guang, Liu, Chun Feng, Xu, Xingshun 01 January 2015 (has links)
Oligodendrocytes are the predominant cell type in white matter and are highly vulnerable to ischemic injury. The role of oligodendrocyte dysfunction in ischemic brain injury is unknown. In this study, we used a 24-amino acid peptide S14G-Humanin (HNG) to examine oligodendrogenesis and neurological functional recovery in a hypoxic/ischemic (H/I) neonatal model. Intraperitoneal HNG pre-treatment decreased infarct volume following H/I injury. Delayed HNG treatment 24 h after H/I injury did not reduce infarct volume but did decrease neurological deficits and brain atrophy. Delayed HNG treatment did not attenuate axonal demyelination at 48 h after H/I injury. However, at 14 d after H/I injury, delayed HNG treatment increased axonal remyelination, the thickness of corpus callosum at the midline, the number of Olig2+/BrdU+ cells, and levels of brain-derived neurotrophic factor (BDNF). Our results suggest that targeting oligodendrogenesis via delayed HNG treatment may represent a promising approach for the treatment of stroke.
45

Identified Issues with the Use of Technology in Treatment of Newborn Infants at Risk of Hypoxic Ischemic Encephalopathy : A study done at the largest obstetric hospital in Hanoi, Vietnam / Identifierade problem i användningen av teknik vid behandling av nyfödda barn med risk för hypoxisk ischemisk encefalopati : En studie gjord på det största obstetriksjukhuset i Hanoi, Vietnam

Papworth, Katja, Wessén, Clara January 2019 (has links)
Neonatal asphyxia is the third largest cause of neonatal mortality in Vietnam, and many of the surviving patients suffer from permanent brain damage. A cooling mattress used for treatment of infants suffering from asphyxia has been shown to have problems with providing a stable body temperature for the patients. The main purpose of this project is to assess potential problems with routines and the use of the most central technical equipment used to treat newborns suffering from asphyxia, as well as constructing a phantom to simulate a newborn infant in the process of cooling. The purpose of the simulation is to investigate new methods of using the cooling mattress to achieve a more stable body temperature when cooling the patient. The project was done at Phu San Hostpial and Vietnam National Children's Hospital in Hanoi, Vietnam. The technical evaluation was conducted with observations, interviews and a question form. The results showed that there were issues with the sensors connected to the ventilators, noise level from alarms and routines concerning sanitation. The phantom was based on a water bottle, an interest heater and a pump to mix the water. It proved not possible to construct a phantom that met the necessary criteria. / Asfyxi hos nyfödda är den tredje största orsaken till neonatal dödlighet i Vietnam, och många av de överlevande får permanenta hjärnskador. En nedkylningsmadrass som används till behandling av nyfödda med asfyxi har visat sig ha problem med att hålla patientens kroppstemperatur stabil. Arbetets huvudsakliga syfte är att undersöka potentiella problem med rutiner och användningen av den viktigaste tekniken vid behandling av nyfödda som lider av asfyxi, samt även konstruera en fantom som ska kunna simulera en nyfödd vid nedkylning. Simuleringen har som syfte att undersöka nya användningsmetoder av nedkylningsmadrassen för att uppnå en mer stabil kroppstemperatur hos patienten. Arbetet gjordes vid Phu San Hospital, och National Children’s Hospital i Hanoi, Vietnam. Utvärderingen av teknikens användning gjordes via observationer, intervjuer och ett frågeformulär. Resultaten sammanställdes för att hitta potentiella förbättringar till teknikens användning. Det framkom problem med sensorerna kopplat till ventilatorerna, ljudnivån från alarmer och rutiner kring sanitering. Fantomet baserades på en vattenflaska, en doppvärmare och en pump som blandade vattnet. Det visade sig inte vara möjligt att konstruera en fantom som uppfyllde alla kriterier med de resurser som var tillgängliga.
46

COVID-19-Induced Takotsubo Cardiomyopathy With Concomitant Pulmonary Embolism

Namburu, Lalith V., Bhogal, Sukhdeep S., Ramu, Vijay K. 01 October 2021 (has links)
Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emerged as a global pandemic with an unprecedented death toll worldwide. Although it primarily affects the respiratory tract presenting as pneumonia or acute respiratory failure, it is also known to cause significant cardiovascular complications, including acute coronary syndrome (ACS), arrhythmia, myopericarditis, cardiomyopathy, venous thromboembolism, heart failure, and cardiogenic shock. Morbidity and mortality secondary to cardiovascular complications are higher in patients with preexisting cardiovascular risk factors. Here, we present a case report of a 69-year-old male who was recently diagnosed with COVID-19 illness presenting with ST-elevation myocardial infarction (STEMI) and eventually with Takotsubo cardiomyopathy (TTC), and the course was complicated by right atrial thrombus and a pulmonary embolism (PE).
47

Intermittent Hypoxia and Neonatal Carotid Body Function

Pawar, Anita 21 July 2009 (has links)
No description available.
48

Maternal Diabetes Mellitus and Neonatal Hearing: A Retrospective Study of Hypoxic/Ischemic Related Risk Factors

Wells, Shana Loleta 30 June 2003 (has links)
No description available.
49

Differential Adult and Neonatal Response to Cerebral Ischemia-Hypoxia

Adhami, Faisal January 2007 (has links)
No description available.
50

The Role of AMP-Activated Protein Kinase (AMPK) in Hypoxic Chemotransduction by the Carotid Body

Jordan, Heidi Lynn 13 June 2012 (has links)
No description available.

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