532 research outputs found

    Anesthesia for Pediatric Lung Transplantation: Case Presentation and Review of the Literature

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    The first pediatric lung transplant was performed in 1987 at the University of Toronto in a 15-year-old with familial pulmonary fibrosis. Since that time, over 2000 children have received lung transplants worldwide, with an annual number ranging between 99 and 137 over the past decade. For the anesthesiologist charged with managing these rare patients, an understanding of the indications that lead to transplantation, their pathophysiology, and the physiology of the transplanted lungs are critical. To provide a context for the anesthetic management of the child undergoing lung transplantation, we discuss the case of a 2-month-old who underwent bilateral lung transplantation for intractable respiratory failure. Both the unique aspects of this case and pediatric lung transplantation, in general, are presented. Then a review of the literature is discussed

    Daily Rhythms of Physiological Parameters in the Dromedary Camel Under Natural and Laboratory Conditions

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    Camels are well adapted to hot arid environments and can contribute significantly to the economy of developing countries in arid regions of the world. Full understanding of the physiology of camels requires understanding of the internal temporal order of the body, as reflected in daily or circadian rhythms. In the current study, we investigated the daily rhythmicity of 20 physiological variables in camels exposed to natural oscillations of ambient temperature in a desert environment and compared the daily temporal courses of the variables. We also studied the rhythm of core body temperature under experimental conditions with constant ambient temperature in the presence and absence of a light-dark cycle. The obtained results indicated that different physiological variables exhibit different degrees of daily rhythmicity and reach their daily peaks at different times of the day, starting with plasma cholesterol, which peaks 24 minutes after midnight, and ending with plasma calcium, which peaks 3 hours before midnight. Furthermore, the rhythm of core body temperature persisted in the absence of environmental rhythmicity, thus confirming its endogenous nature. The observed delay in the acrophase of core body temperature rhythm under constant conditions suggests that the circadian period is longer than 24 hours. Further studies with more refined experimental manipulation of different variables are needed to fully elucidate the causal network of circadian rhythms in dromedary camels

    FastSurfer-HypVINN: Automated sub-segmentation of the hypothalamus and adjacent structures on high-resolutional brain MRI

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    The hypothalamus plays a crucial role in the regulation of a broad range of physiological, behavioural, and cognitive functions. However, despite its importance, only a few small-scale neuroimaging studies have investigated its substructures, likely due to the lack of fully automated segmentation tools to address scalability and reproducibility issues of manual segmentation. While the only previous attempt to automatically sub-segment the hypothalamus with a neural network showed promise for 1.0 mm isotropic T1-weighted (T1w) MRI, there is a need for an automated tool to sub-segment also high-resolutional (HiRes) MR scans, as they are becoming widely available, and include structural detail also from multi-modal MRI. We, therefore, introduce a novel, fast, and fully automated deep learning method named HypVINN for sub-segmentation of the hypothalamus and adjacent structures on 0.8 mm isotropic T1w and T2w brain MR images that is robust to missing modalities. We extensively validate our model with respect to segmentation accuracy, generalizability, in-session test-retest reliability, and sensitivity to replicate hypothalamic volume effects (e.g. sex-differences). The proposed method exhibits high segmentation performance both for standalone T1w images as well as for T1w/T2w image pairs. Even with the additional capability to accept flexible inputs, our model matches or exceeds the performance of state-of-the-art methods with fixed inputs. We, further, demonstrate the generalizability of our method in experiments with 1.0 mm MR scans from both the Rhineland Study and the UK Biobank. Finally, HypVINN can perform the segmentation in less than a minute (GPU) and will be available in the open source FastSurfer neuroimaging software suite, offering a validated, efficient, and scalable solution for evaluating imaging-derived phenotypes of the hypothalamus.Comment: Submitted to Imaging Neuroscienc

    Natural Radioactivity and Radiological Hazard Effects from Granite Rocks in the Gabal Qash Amir Area, South Eastern Desert, Egypt

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    The existence of radioactivity linked to the heavy-bearing minerals in building materials—such as granite—has increased attention to the extraction procedure. Granite rocks play an essential economic role in various areas of Egypt. Thus, this study intended to detect the 238U, 232Th, and 40K activity concentrations in the examined granite samples and to determine the corresponding radiological risks associated with the granite. The studied rocks were collected in the Gabal Qash Amir area (south Eastern Desert, Egypt). The obtained results of the activity concentrations for 238U (193 ± 268) Bq/kg, 232Th (63 ± 29) Bq/kg, and 40K (1034 ± 382) Bq/kg indicated that there were moderate concentrations in the investigated samples, which were greater than the worldwide average. The radioactivity levels in the studied granite samples are due to the secondary alteration of radioactive-bearing minerals associated with cracks of granites (secondary minerals in muscovite granites are wolframite, uraninite, uranophane, beta-uranophane, autunite, xenotime, columbite, zircon, and monazite). The radiological risk assessment for the public from the radionuclides that were associated with the studied granite samples was predicted via estimating the radiological hazard factors, such as the radium equivalent content (362 Bq kg−1), compared with the recommended limit. The dosing rate Dair in the air (169.2 nGy/h), the annual effective dose both outdoors (AEDout ~ 0.21 ± 0.17 mSv) and indoors (AEDin ~ 0.83 ± 0.67 mSv), the annual gonadal dose equivalent (AGDE ~ 1.18 ± 0.92 mSv), as well as the external (Hex) and internal (Hin) hazard indices (>1), and another factor were associated with excess lifetime cancer risk. According to the statistical investigation, the studied granites were inappropriate for use in construction and infrastructure fields. They may induce health problems due to the radioactivity levels, which exceed the recommended limits. © 2022 by the authors.King Khalid University, KKU: KKU/RCAMS/22The authors would like to thank the Nuclear Materials Authority, Egypt. This work was supported by King Khalid University through a grant (KKU/RCAMS/22) under the Research Center for Advanced Materials Science (RCAMS) at King Khalid University, Saudi Arabia

    Direct heat stress-induced effects on rumen fermentation characteristics and nutrients degradability in sheep pair-fed alfalfa hay

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    Aim of the study: To investigate the direct effect of heat stress on rumen fermentation characteristics and nutrients degradability of pair-fed rams to subsequently eliminate the confounding effects of dissimilar feed intake induced by heat stress exposure.Area of study: Saudi Arabia.Material and methods: Five rumen-cannulated desert rams (45 ± 1.63 kg body weight; 2–3 years of age) were placed individually in controlled climatic-chambers to be exposed to two successive periods. The 1st period was a control thermoneutral period (TN; 23.64 ± 0.14 °C; extended for 21 days) followed by a 2nd period of heat stress (HS; 44.26 ± 1.70 °C, for another 21 days). Each period was consisted of a temperature acclimation phase (7 days) and a data collection phase (14 days). Alfalfa hay was offered twice daily during both periods in a pair-fed manner (800 g DM per head and day).Main results: Exposing pair-fed desert rams to elevated ambient temperature had (p<0.05) elevated their respiration rate and skin temperature, without noticeable (p>0.05) changes in their rectal temperature. Most of the rumen fermentation characteristics and nutrients degradability were not affected by HS (p>0.05). However, exposure to HS increased (p<0.05) pre-feeding rumen total volatile fatty acids concentrations, pre-feeding molar proportion of acetate, and post-feeding rumen osmolality.Research highlights: HS had no direct effect on post-feeding rumen fermentation characteristics and nutrients degradability in desert sheep. This implies that strategic approaches to mitigate the adverse effects of HS have to be directed towards promoting feed intake and nutrients utilization under such conditions

    Role of evolutionary epidemiology in the determination of the risk factors associated with some equine viral diseases

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    The evolutionary epidemiology is crucial as it does not only help in tracking the origin, spreading, prediction, and control of viruses but also explains the failure causes of some vaccines and serological diagnostic tools. To keep animal welfare, it is essential to raise awareness of the multiple risk factors associated with the different epidemics. Arthropod-borne viruses like African horse sickness virus (AHSV) and equine infectious anaemia virus (EIAV) are related to vectors multiplication. Accordingly, their seasonal occurrence was attributed to the environmental climatic conditions. While equine influenza virus (EIV) and equine herpes virus (EHV) were found to occur in winter and spring (foaling seasons), respectively. The management risk factors resulted in the occurrence and reactivation of latently infected cases. The RNA viruses are characterized by genetic assortment which results in increasing pathogenicity, and failure of the used vaccines. The EHVs able to establish infection in different host tissues adding to their immune evasion strategies. Most of the diseases occurred at the age over 2 years although the EIAV takes long time to appear. The hard work of males and other stress factors render them more liable for infection with equine viral arteritis (EVA), EIAV, and EHV. Genetically, some breeds of horses were at risk of AHSV, EVA, and EHV infection. Most of the donkeys, mules, and zebra develop subclinical forms that magnifies their role in the epidemiological situation. Different phenomena like overwintering in AHSV, hard work in EIV, virus hidden nature and latency in EHV should be more analysed

    Improving the elevated-temperature mechanical properties of AA3004 hot-rolled sheets by microalloying with Mo and optimizing the process route

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    The present work investigated the influence of Mo addition and thermomechanical process routes on microstructural evolution and elevated-temperature mechanical properties of Al–Mn–Mg 3004 alloys. Various combinations of heat treatment and hot rolling were applied to fabricate hot-rolled sheets. The results revealed that microalloying with Mo and two-step heat treatment increased the number density and volume fraction of dispersoids and decreased the volume fractions of dispersoid-free zones. The different processing routes had important impacts on microstructural evolution. The alloys processed with heat treatment followed by hot rolling had finer and better distributions of dispersoids than those subjected to hot rolling prior to heat treatment. The former resulted in higher tensile strengths at room and elevated temperatures. Among all conditions, the Mo-containing alloy subjected to two-step heat treatment followed by hot rolling exhibited the highest elevated-temperature properties and reached a yield strength of 93 MPa at 300 °C. Both the base and Mo-containing alloys subjected to two-step heat treatment followed by hot rolling showed excellent thermal stabilities up to 350 °C and almost no significant change in yield strengths after thermal exposure at 300–350 °C for 100 h

    Epidemiological aspects of some equine viral diseases

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    Although different equine viruses’ outbreaks have been recorded. However, the most important ones in are the African horse sickness virus (AHSV), equine influenza virus (EIV), equine viral arteritis (EVA), Equine infectious anaemia virus (EIAV), and equine herpes viruses (EHV). To combat these diseases, it is imperative to understand their epidemiological aspects. So, the current review aims to highlight some epidemiological aspects including; causative agents, clinical forms, history, prevalence and geographical distribution, source of infection, and methods of transmission. The AHSV mainly causes pulmonary, and cardiac forms with high morbidity and mortality rates in Africa. The EIV is found all over the world and results in respiratory signs. The EVA has low morbidity and mortality rates and is mainly found in the Americas and Europe, its significance is due to the reproductive problems as abortion in mares and subfertility in stallions. The EIAV has low morbidity and mortality rates and causes long time course disease mainly of fever, and chronic anaemia or death. The EHVs are the current most important pathogens due to their endemicity all over the world and their high morbidity. It causes respiratory, abortion, neonatal, and sometimes neurological manifestations. Aerosols and body excretions are the main sources of infection with EIV, EVA, and EHV. Venereal EVA transmission occurs through natural breeding or artificial insemination with the semen of infected or carrier stallions. The spreading of arboviruses is greatly affected by the vector activity like the AHSV which transmitted by the the Culicoide. imicola biting midges, and the EIAV by family Tabanidae. In general, it is recommended to take all epidemiological measures, including vaccinations and vector control, to limit the spread of such diseases and reduce economic losses
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