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The present study investigated the transmission of exhaled particles generated by coughing inside a car cabin, considering eleven different window opening configurations. The results indicated that particle dispersion and removal were mainly affected by the airflow, which was largely determined by the window opening configurations. Notably, efficient ventilation and a large number of open windows did not necessarily result in lower infection risk. Given the complex structure and formation of intricate airflow patterns within the cabin, airborne particles could spread throughout the cabin and deposit on the interior walls. As particles tended to escape or deposit rapidly within the first 10 s, precautionary measures were necessary during this time frame following a passenger's coughing activity. Furthermore, closing the window adjacent to the driver effectively reduced the proportion of exhaled particles passing through the driver's breathing zone due to the rear-in and front-out airflow pattern, thus mitigating the risk of infection. [ABSTRACT FROM AUTHOR]

In this study, the flow boiling heat transfer and pressure drop characteristics of refrigerant R134a in micro-channels were experimentally investigated. The tests were performed in circular horizontal micro-channels with inner diameters of 0.5 mm and 1 mm and a heating length of 300 mm. The mass velocities varied from 500 kg/m²s to 2500 kg/m²s, and the heat fluxes varied from 15 kW/m² to 147 kW/m². The heat transfer coefficient (HTC) and frictional pressure drop (FPD) were measured and discussed in detail. According to the results, HTC was significantly affected by heat flux, whereas it was independent of mass velocity. Nucleate boiling was the dominant heat transfer mechanism for R134a flow boiling in the micro-channels. In comparison to the 1 mm channel, the 0.5 mm channel shows better performance in heat transfer, with a maximum increase of approximately 22 %. In addition, FPD increased with increasing mass velocity and decreasing channel diameter. Finally, several existing correlations for HTC and FPD were evaluated by comparing them with the experimental values. Tran's correlation (1996) presented a better agreement in terms of the average HTC, while for the FPD, the model of Kim and Mudawar (2013b) showed good prediction accuracy. [ABSTRACT FROM AUTHOR]

The flow boiling heat transfer characteristics of R245fa in segmented internally-threaded tubes are studied experimentally. The heat transfer performances of smooth tube, front-threaded tube, rear-threaded tube, and full-threaded tube are compared. The experiments are carried out with heat flux ranging from 14.01 to 48.79 kW·m-2 and mass flux ranging from 125 to 375 kg·m-2·s-1. The experimental results show that the internal thread structure facilitates the heat transfer. At low mass fluxes and low heat fluxes, the heat transfer performance of the full-threaded tube is the best, while at high heat fluxes and high mass fluxes, that of the front-threaded tube is the best. Convective boiling is dominant in the smooth tube and the front-threaded tube, and corresponding heat transfer coefficients increase significantly with increasing mass flux. In contrast, nucleate boiling dominates in the rear- and full-threaded tube, and the heat transfer coefficients almost keep unchanged with increasing mass flux. The front- and rear-threaded tubes exhibit significantly different heat transfer characteristics, although they have the same heat transfer area. The effect of convective perturbation and bubble nucleation caused by the internal thread structure varies with the zone and intensity, leading to the change of the dominant mechanism of boiling heat transfer. [ABSTRACT FROM AUTHOR]

Objective: This study was conducted to analyze the clinical characteristics and pituitary function of patients with primary empty sella (PES). Methods: The clinical data from 123 hospitalized adult patients with PES from January 2010 to May 2016 were retrospectively studied. Results: (1) The average age of the 123 (male 43, female 80) PES patients was (59.2±13.6) years (ranging 24-92 years), among whom 61% patients were in the age group between 50-69 years. (2) The symptoms of the patients included fatigue (56.1%), headache (34.1%), nausea and vomiting (17.9%), gonadal dysfunction (17.1%), visual disturbance (5.7%) and hypopituitarism crisis (3.3%). (3) Hypopituitarism was found in 66 of the 123 patients. Among them, 36.6%, 31.7% and 17.1% were central hypoadrenalism, hypogonadism, and hypothyroidism, respectively.The percentage of hypopituitarism in complete PES was significantly higher than that in partial PES ( P <0.05). (4) Sixteen patients were concomitant with other autoimmune diseases including 11 patients with Graves' disease and 2 with Cushing's syndrome due to adrenal adenoma. Conclusions: The incidence of hypopituitarism in PES was 53.7%, in which the pituitary-adrenal axis hypofunction was more common. An overall evaluation of the pituitary function was essential for the patients who had headache and fatigue, or with suspected PES. The patients with hypopituitarism should be given hormone replacement therapy in time and followed up afterword.

To study the effect of hypoxia on humoral immunity function of rat and Ochotona curzoniae (pika), the specific antibody production to novel antigen IgG and immunoresponse to sheep red blood cell (hemolysin forming) were measured. The results show that hypoxia at altitude of 5 km and 7 km for 10 d resulted respectively in 10.3% (P < 0.05) and 21.9% (P < 0.05) decrement in hemolysin formation in rats, as compared with the control group kept at 2.3 km. When the rats were secondarily immunized and kept at the same hypoxia for 10 d, the reduction in hemolysin formation was 4.2% (P < 0.05) and 4.6% (P < 0.05) for the two respective altitudes. These changes, however, were not found in pikas. When rats were immunized two days before hypoxia, 5 km hypoxia for 5 d and 8 d failed to suppress hemolysin formation. Intracerebroventricular (i.c.v.) injection of CRF (1.0 microgram/rat), decreased hemolysin formation and production of IgG by 8.6% (P < 0.05) and 14.0% (P < 0.05) respectively, but intraperitoneal (i.p.) injection of CRF (1.0 microgram/rat) had no effect. On the other hand, i.c.v. injection of CRF receptor antagonist (alpha-helical CRF (9-41), 50 micrograms/rat) prior to 7 km hypoxia caused a hypoxia-induced suppression of IgG production from 24.2% to 12.1% (P < 0.05). Adrenalectomy in rats lowered hemolysin formation by 6.6% (P < 0.05). The above results demonstrate that hypoxia suppresses humoral immunity function and alters initial antigen processing probably through an increase of CRF in the central nervous system.