Assessing spatial variability of extreme hot weather conditions in Hong Kong: A land use regression approach.

The number of extreme hot weather events have considerably increased in Hong Kong in the recent decades. The complex urban context of Hong Kong leads to a significant intra-urban spatial variability in climate. Under such circumstance, a spatial understanding of extreme hot weather condition is urgently needed for heat risk prevention and public health actions. In this study, the extreme hot weather events of Hong Kong were quantified and measured using two indicators - very hot day hours (VHDHs) and hot night hours (HNHs) which were counted based on the summertime hourly-resolved air temperature data from a total of 40 weather stations (WSs) from 2011 to 2015. Using the VHDHs and HNHs at the locations of the 40 WSs as the outcome variables, land use regression (LUR) models are developed to achieve a spatial understanding of the extreme hot weather conditions in Hong Kong. Land surface morphology was quantified as the predictor variables in LUR modelling. A total of 167 predictor variables were considered in the model development process based on a stepwise multiple linear regression (MLR). The performance of resultant LUR models was evaluated via cross validation. VHDHs and HNHs were mapped at the community level for Hong Kong. The mapping results illustrate a significant spatial variation in the extreme hot weather conditions of Hong Kong in both the daytime and nighttime, which indicates that the spatial variation of land use configurations must be considered in the risk assessment and corresponding public health management associated with the extreme hot weather.

Acute Myocardial Infarction and Concomitant Stroke as the Manifestations in a Patient with Type A Aortic Dissection: A Case Report with Three Years of Follow-Up.

A 55-year-old male patient presented with repeated acute retrosternal chest pain. Twelve-lead electrocardiogram and cardiac enzymes revealed non-ST elevation myocardial infarction. He was treated as non-ST elevation myocardial infarction at first. The symptoms of left-sided hemiparesis and aphasia occurred later on after admission. The results of emergent brain computed tomography and magnetic resonance imagining demonstrated acute stroke. The unusual presentation warned us of the possibility of aortic dissection. Besides the reports of heart and vessels computed tomography indicated aortic dissection as the underlying cause. Emergent surgical repair with preservation of the aortic valve led to a good recovery of heart and cerebral function. To the best of our knowledge, there were only three cases in the review of literature presenting with acute myocardial infarction and concurrent stroke resulting from acute aortic dissection.

Real-time subpixel-accuracy tracking of single mitochondria in neurons reveals heterogeneous mitochondrial motion.

Mitochondria are essential for cellular survival and function. In neurons, mitochondria are transported to various subcellular regions as needed. Thus, defects in the axonal transport of mitochondria are related to the pathogenesis of neurodegenerative diseases, and the movement of mitochondria has been the subject of intense research. However, the inability to accurately track mitochondria with subpixel accuracy has hindered this research. Here, we report an automated method for tracking mitochondria based on the center of fluorescence. This tracking method, which is accurate to approximately one-tenth of a pixel, uses the centroid of an individual mitochondrion and provides information regarding the distance traveled between consecutive imaging frames, instantaneous speed, net distance traveled, and average speed. Importantly, this new tracking method enables researchers to observe both directed motion and undirected movement (i.e., in which the mitochondrion moves randomly within a small region, following a sub-diffusive motion). This method significantly improves our ability to analyze the movement of mitochondria and sheds light on the dynamic features of mitochondrial movement.

Prolonged non-survival in PICU: does a do-not-attempt-resuscitation order matter.

BACKGROUND: Etiologies of pediatric intensive care unit (PICU) mortality are diverse. This study aimed to investigate the pattern of PICU mortality in a regional trauma center, and explore factors associated with prolonged non-survival. METHODS: Demographic data of all PICU deaths in a regional trauma center were analyzed. Factors associated with prolonged nonsurvival (length of stay) were investigated with univariate log rank and multivariate Cox-Regression forward stepwise tests. RESULTS: There were 88 deaths (males 61%; infants 23%) over 10 years (median PICU stay = 3.5 days, interquartile range: 1 and 11 days). The mean annual mortality rate of PICU admissions was 5.8%. Septicemia with gram positive, gram negative and fungal pathogens were present in 13 (16%), 13 (16%) and 4 (5%) of these patients, respectively. Viruses were isolated in 25 patients (28%). Ninety percent of these 88 patients were ventilated, 75% required inotropes, 92% received broad spectrum antibiotic coverage, 32% received systemic corticosteroids, 56% required blood transfusion and 39% received anticonvulsants. Thirty nine patients (44%) had a DNAR (Do-Not-Attempt-Resuscitation) order with their deaths at the PICU. Comparing with non-trauma category, trauma patients had higher mortality score, no premorbid disease, suffered asystole preceding PICU admission and subsequent brain death. Oncologic conditions were the most prevalent diagnosis in the non-trauma category. There was no gunshot or asthma death in this series. Prolonged non-survival was significantly associated with DNAR, fungal infections, and mechanical ventilation but negatively associated with bacteremia. CONCLUSIONS: Death in the PICU is a heterogeneous event that involves infants and children. Resuscitation was not attempted at the time of their deaths in nearly half of the patients in honor of parents' wishes. Parents often make DNAR decision when medical futility becomes evident. They could be reassured that DNAR did not mean "abandoning" care. Instead, DNAR patients had prolonged PICU stay and received the same level of PICU supports as patients who did not respond to cardiopulmonary resuscitation.