[Spatiotemporal variations of wet-bulb temperature and its impact factors of Nanjing urban neighborhood]. / å—äº¬åŸŽå¸‚è¡—åŒºæ¹¿çƒæ¸©åº¦æ—¶ç©ºå˜åŒ–ç‰¹å¾åŠå ¶å½±å“å› å­.

Global climate change and local urban heat islands enhance urban heat stress. Studies focused at the urban neighborhood scale are limited. Wet-bulb temperature represents the combined effects of both temperature and humidity, and therefore can more accurately reflect human thermal comfort. In this study, air temperature, relative humidity and geographic information of different times, seasons, and sky conditions of the Nanjing Jiangbei New Area were obtained based on mobile measurements. The spatiotemporal variation of wet-bulb temperature at the urban neighborhood scale and the effects of sky conditions, land cover and urban morphology (sky view factor, SVF) were further analyzed. The results showed that: 1) the spatiotemporal variations of wet-bulb temperature at the Nanjing urban neighborhood scale were consistent with that of air temperature. Compared with vapor pressure, air temperature played a dominant role. The extremely high values of wet-bulb temperature in this area were mostly caused by the synergy between air temperature and vapor pressure. 2) The correlation between SVF and wet-bulb temperature was significantly positive in the daytime and negative at night. An increase in the vegetation fraction could reduce wet-bulb temperature, while impervious surfaces had the opposite effect. The wet-bulb temperature significantly decreased and its spatial distribution was much more homogeneous under overcast sky conditions. 3) The horizontal scale effect showed diurnal and seasonal differences and was more sensitive to sky conditions during nighttime than during daytime. Compared with vegetation, the horizontal effect of impervious surfaces was much larger in winter than in the other two seasons. The horizontal scale effects of vege-tation and impervious surfaces on wet-bulb temperature were similar to those of air temperature. These results could provide effective scientific support and a theoretical basis for improving and optimizing the thermal environment of urban neighborhoods, as well as alleviating urban heat stress.

Rutin attenuates isoflurane-induced neuroapoptosis via modulating JNK and p38 MAPK pathways in the hippocampi of neonatal rats.

An increasing number of infants and children undergo surgery and are exposed to anesthesia as a part of medical care each year. Isoflurane is a commonly used anesthetic in the pediatric population. However, previous studies have reported widespread isoflurane-induced neuroapoptosis and cognitive impairments in neonatal animal models, raising concerns over the administration of isoflurane in the pediatric population. The current study investigated the effects of rutin, a flavonoid, on isoflurane-induced neuroapoptosis in a neonatal rodent model. Groups of neonatal rat pups were administered rutin at doses of 10, 20 or 40 mg/kg body weight from postnatal day 1 (P1) to P15. On P7, pups were exposed to 0.75% isoflurane for 6 h. Rat pups in the control groups did not receive rutin, and did not receive anesthesia in one group. Neuroapoptosis following isoflurane exposure was determined by TUNEL assay. The expression levels of cleaved caspase-3, apoptotic pathway proteins [Bcl2-associated agonist of cell death (Bad), phospho-Bad, Bax, B-cell lymphoma 2 (Bcl-2) and Bcl-xL and mitogen-activated protein kinases (MAPK)] signalling pathway proteins [c-Jun N-terminal kinase (JNK), phospho-JNK, extracellular-signal-regulated kinase 1/2 (ERK1/2), phosphoERK1/2, p38, phospho-p38 and phospho-c-Jun], were determined by western blot analysis. The Morris water maze test was used to assess the learning and memory of pups on P30 and P31. The present study found that rutin at the tested doses of 10, 20 and 40 mg significantly reduced (P<0.05) the isoflurane-induced elevation in apoptotic cell count. The expression levels of caspase-3, Bad, Bax and MAPK proteins, which were increased following isoflurane treatment, were rescued by rutin treatment. Furthermore, rutin prevented the increase in Bcl-xL, Bcl-2 and phospho-Bad expression following isoflurane treatment, and enhanced the memory of the rats. Rutin provided neuroprotection against isoflurane-induced neuronal apoptosis and improved the learning and memory of rats by effectively regulating the expression levels of proteins in the MAPK pathway.