Уточнить поиск
Результаты 1-8 из 8
Experimental and modeled thermoregulatory costs of repeated sublethal oil exposure in the Double-crested Cormorant, Phalacrocorax auritus
2018
Mathewson, Paul D. | Hanson-Dorr, Katie C. | Porter, Warren P. | Bursian, Steven J. | Dean, Karen M. | Healy, Kate | Horak, Katherine | Link, Jane E. | Harr, K.E. | Dorr, Brian S.
To fully understand the impact of oil exposure, it is important to understand sublethal effects like how increased thermoregulatory costs may affect survival and reproduction. However, it is difficult and time-consuming to measure these effects in wild animals. We present a novel use of a bioenergetics model, Niche Mapper™, to estimate thermoregulatory impacts of oiling, using data from captive Double-crested Cormorants (Phalacrocorax auritus) experimentally exposed to oil. Oiled cormorants had significant increases in surface body temperatures following exposure. Niche Mapper accurately predicted surface temperatures and metabolic rates for unoiled and oiled cormorants and predicted 13–18% increased daily energetic demands due to increased thermoregulatory costs of oiling, consistent with increased food consumption observed in experimentally oiled cormorants. We show that Niche Mapper can provide valuable insight into sublethal oiling effects by quantifying the extent to which thermoregulatory costs divert energy resources away from important life processes like maintenance, reproduction and migration.
Показать больше [+] Меньше [-]An updated review on cattle thermoregulation: physiological responses, biophysical mechanisms, and heat stress alleviation pathways
2021
dos Santos, Mateus Medeiros | Souza-Junior, João Batista Freire | Dantas, Maiko Roberto Tavares | de Macedo Costa, Leonardo Lelis
Heat stress is one of the main obstacles to achieving efficient cattle production systems, and it may have numerous adverse effects on cattle. As the planet undergoes climatic changes, which is predicted to raise the earth’s average temperature by 1.5 °C between 2030 and 2052, its impact may trigger several stressful factors for livestock. Among these, an increase in core body temperature would trigger physiological imbalance, consequently affecting reproduction, animal health, and dry matter intake adversely. Core body temperature increase is commonly observed and poses challenges to livestock farmers. In cattle farming, thermal stress severely affects milk production and weight gain, and can compromise food security in the coming years. This review presents an updated approach to the physiological and thermoregulatory responses of cattle under various environmental conditions. Strategies for mitigating the harmful effects of heat stress on livestock are suggested as viable alternatives for the betterment of production systems.
Показать больше [+] Меньше [-]Heat-related illnesses in a mass gathering event and the necessity for newer diagnostic criteria: a field study
2021
Alkassas, Wesam | Rajab, Ahmad Mamoun | Alrashood, Sara T. | K̲h̲ān, Muḥammad Ayyūb | Dibas, Mahmoud | Zaman, Mohsin
Heat-related illnesses (HRIs), mainly heat exhaustion (HE) and heat stroke (HS), are characterized by an elevation of core body temperature. In this study, we aimed to explore the HRIs’ types and patient characteristics among a sample taken from various representative in-field points in the Hajj season. A cross-sectional study was conducted in 2018 at 80 data collection points distributed in the field. Data related to demographics, features and risk factors were collected and analyzed from all encountered cases with suspected HRIs. Moreover, we developed a diagnostic tree for HRIs by using the XGBoost model. Out of the 1200 persons encountered during the study period, 231 fulfilled the criteria of HRIs spectrum and were included in this study. Around 6% had HS and 20% had HE. All HS cases (100%) were from outside of Saudi Arabia as compared with 72.5% diagnosed with HE (27.5% were from Saudi Arabia). In addition, 16% were considered as heat-induced muscle spasms, and 7% had limb heat edema. Additionally, most of HRIs cases were reported between 11 am and 1 pm. The HRIs diagnostic tree model gave a diagnostic accuracy of 93.6%. This study highlights the magnitude of HRIs among pilgrims in Hajj and provides a diagnostic tree that can aid in the risk stratification and diagnosis of these patients. We advise the implementation of more educational campaigns to pilgrims regarding preventable measures especially for the vulnerable groups (e.g. from outside Saudi Arabia, those with comorbidities and light-skinned people).
Показать больше [+] Меньше [-]Assessment of airborne transmission from coughing processes with thermal plume adjacent to body and radiators on effectiveness of social distancing
2022
Issakhov, Alibek | Omarova, Perizat | Borsikbayeva, Aliya
The new coronavirus disease COVID-19 has caused a worldwide pandemic to be declared in a very short period of time. The complexity of the infection lies in asymptomatic carriers that can inadvertently transmit the virus through airborne droplets. This kind of viral disease can infect the human body with tiny particles that carry various bacteria that are generated by the respiratory system of infected patients. In this study, numerical results are proposed that demonstrate the effect of human body temperature and temperature from radiators in a room on the spread of the smallest droplets and particles in an enclosed space. The numerical model proposed in this work takes into account the sedimentation of particles and droplets under the action of gravitational sedimentation and transport in a closed room during the processes of breathing, sneezing or coughing. Various cases were considered, taking into account normal human breathing, coughing or sneezing, as well as three different values of the rate of emission of particles from the human mouth. The heat plume, which affects the concentration of particles in the breathing zone, spreads the particle up to a distance of 4.29 m in the direction of the air flow. It can also be seen from the results obtained that the presence of radiators strongly affects the propagation of particles of various sizes in a closed room. From the obtained results, it should be noted that in order to recommend the optimal social distance, it is necessary to take into account many factors, especially momentum, gravity, human body temperature, as well as the process of natural convection, which greatly affect the propagation of particles in a closed room. The conclusions drawn from the results of this work show that, given the environmental conditions, the social distance of 2 m may not be enough.
Показать больше [+] Меньше [-]Transmission of SARS-CoV-2 virus and ambient temperature: a critical review
2021
Mu, Yunsong | Shao, Meichen | Zhong, Buqing | Zhao, Yiqun | Leung, Kenneth M. Y. | Giesy, John P. | Ma, Jin | Wu, Fengchang | Zeng, Fangang
The coronavirus disease 2019 (COVID-19) pandemic has brought unprecedented public health, and social and economic challenges. It remains unclear whether seasonal changes in ambient temperature will alter spreading trajectory of the COVID-19 epidemic. The probable mechanism on this is still lacking. This review summarizes the most recent research data on the effect of ambient temperature on the COVID-19 epidemic characteristic. The available data suggest that (i) mesophilic traits of viruses are different due to their molecular composition; (ii) increasing ambient temperature decreases the persistence of some viruses in aquatic media; (iii) a 1°C increase in the average monthly minimum ambient temperatures (AMMAT) was related to a 0.72% fewer mammalian individuals that would be infected by coronavirus; (iv) proportion of zoonotic viruses of mammals including humans is probably related to their body temperature difference; (v) seasonal divergence between the northern and southern hemispheres may be a significant driver in determining a waved trajectory in the next 2 years. Further research is needed to understand its effects and mechanisms of global temperature change so that effective strategies can be adopted to curb its natural effects. This paper mainly explores possible scientific hypothesis and evidences that local communities and authorities should consider to find optimal solutions that can limit the transmission of SARS-CoV-2 virus.
Показать больше [+] Меньше [-]Evaluation of Pediatric Early Warning System and Drooling Reluctance Oropharynx Others Leukocytosis scores as prognostic tools for pediatric caustic ingestion: a two-center, cross-sectional study
2022
Sharif, Asmaa Fady | Gameel, Dina El Gameel El | Abdo, Sanaa Abd El-Fatah | Elgebally, Elsayed Ibrahim | Fayed, Manar Maher
Caustic chemicals are widely distributed in our environment. Exposure to caustic agents is a lifelong problem associated with severe tissue and mucous membrane injuries. In pediatrics, corrosive exposure is the most common cause of nonpharmaceutical exposure presenting to poison control centers. Therefore, this study evaluated the role of the Pediatric Early Warning System (PEWS) and Drooling Reluctance Oropharynx Others Leukocytosis (DROOL) scores as early in-hospital outcome predictors following corrosive ingestion. The current study was a two-center, retrospective, cross-sectional study carried out among pediatric patients diagnosed with acute caustic ingestion during the past 4 years. Most exposure occurred accidentally among boys (59.4%) living in rural areas (51.9%) of preschool age (50% were 2–4 years old). Residence, body temperature, respiratory rate, vomiting, skin and mucosal burns, retrosternal pain, respiratory distress, Oxygen (O2) saturation, Glasgow Coma Scale score, HCO₃ level, total bilirubin level, anemia, leukocytosis, and presence of free peritoneal fluid were significant predictors of esophageal injuries (p < 0.05). DROOL and PEWS scoring were the most significant predictors of esophageal injuries with worthy predictive power, where odds ratio (95% confidence interval (CI)) was 1.76 (0.97–3.17) and 0.47 (0.21–0.99) for PEWS and DROOL, respectively. At a cutoff of < 6.5, the DROOL score could predict esophageal injuries excellently, with AUC = 0.931; sensitivity, 91.7%; specificity, 72.5%; and overall accuracy, 91.3%. At a cutoff of > 6.5, PEWS could significantly predict unfavorable outcomes, with AUC = 0.893; sensitivity, 94.4%; specificity, 71.9%; and overall accuracy, 89.3%. However, PEWS better predicted the need for admittance to the intensive care unit (ICU). Pediatric Early Warning System (PEWS) and Drooling Reluctance Oropharynx Others Leukocytosis (DROOL) are potentially useful accurate scorings that could predict the esophageal injuries and ICU admission following corrosive ingestion in pediatrics.
Показать больше [+] Меньше [-]Virucidal activity of microalgae extracts harvested during phycoremediation of swine wastewater
2022
Michelon, William | Zuchi, Isabella Dai Pra | Reis, Jacqueline Graff | Matthiensen, Alexandre | Viancelli, Aline | da Cruz, Ariadne Cristiane Cabral | Silva, Izabella Thaís | Fongaro, Gislaine | Soares, Hugo Moreira
Phycoremediation of swine wastewater is a promising treatment since it efficiently removes nutrients and contaminants and, simultaneously, its biomass can be harvested and used to obtain a wide range of valuable compounds and metabolites. In this context, biomass microalgae were investigated for the phycoremediation of swine wastewater, and biomass extracts for its virucidal effect against enveloped and non-enveloped viruses. Microalgae were cultivated in a pilot scale bioreactor fed with swine wastewater as the growth substrate. Hexane, dichloromethane, and methanol were used to obtain the microalgae extracts. Extracts were tested for virucidal potential against HSV-1 and HAdV-5. Virucidal assays were conducted at temperatures that emulate environmental conditions (21 °C) and body temperature (37 °C). The maximum production of microalgae biomass reached a concentration of 318.5 ± 23.6 mgDW L⁻¹. The results showed that phycoremediation removed 100% of ammonia-N and phosphate-P, with rates (k₁) of 0.218 ± 0.013 and 0.501 ± 0.038 (day⁻¹), respectively. All microalgae extract reduced 100% of the infectious capacity of HSV-1. The microalgae extracts with dichloromethane and methanol showed inhibition activities at the lowest concentration (3.125 µg mL⁻¹). Virucidal assays against HAdV-5 using microalgae extract of hexane and methanol inhibited the infectious capacity of the virus by 70% at all concentrations tested at 37 °C. At a concentration of 12.5 µg mL⁻¹, the dichloromethane microalgae extract reduced 50–80% of the infectious capacity of HAdV-5, also at 37 °C. Overall, the results suggest that the microalgae can be an attractive source of feedstock biomass for the exploration of alternative virucidal compounds.
Показать больше [+] Меньше [-]Influence of pH, particle size and crystal form on dissolution behaviour of engineered nanomaterials
2017
Solubility is a critical component of physicochemical characterisation of engineered nanomaterials (ENMs) and an important parameter in their risk assessments. Standard testing methodologies are needed to estimate the dissolution behaviour and biodurability (half-life) of ENMs in biological fluids. The effect of pH, particle size and crystal form on dissolution behaviour of zinc metal, ZnO and TiO₂ was investigated using a simple 2 h solubility assay at body temperature (37 °C) and two pH conditions (1.5 and 7) to approximately frame the pH range found in human body fluids. Time series dissolution experiments were then conducted to determine rate constants and half-lives. Dissolution characteristics of investigated ENMs were compared with those of their bulk analogues for both pH conditions. Two crystal forms of TiO₂ were considered: anatase and rutile. For all compounds studied, and at both pH conditions, the short solubility assays and the time series experiments consistently showed that biodurability of the bulk analogues was equal to or greater than biodurability of the corresponding nanomaterials. The results showed that particle size and crystal form of inorganic ENMs were important properties that influenced dissolution behaviour and biodurability. All ENMs and bulk analogues displayed significantly higher solubility at low pH than at neutral pH. In the context of classification and read-across approaches, the pH of the dissolution medium was the key parameter. The main implication is that pH and temperature should be specified in solubility testing when evaluating ENM dissolution in human body fluids, even for preliminary (tier 1) screening.
Показать больше [+] Меньше [-]