EFFECT OF ADDED DIETARY CALCIUM ON ESOPHAGEAL EPITHELIAL-CELL PROLIFERATION IN SUBJECTS AT HIGH RISK FOR ESOPHAGEAL CANCER: A DOUBLE-BLIND INTER-VENTION STUDY

A randomized double-blind intervention trial was carried determine whether oral calcium supplementation could lower the proliferation of epithelial cells of the esophagus. 41 subjects identified with precancerous lesions by histopathology were randomized to receive oral supplementation of their conventional diets with 0.6 g of calcium as calcium carbonate or placebo. Both at the entry to the study and at the end of the treatment, seven months later, the subjects were examined, with an emphasis on the frequency and distribution of proliferating epithelial cells of the esophagus. Patterns of cell proliferation was defined by dividing the esophageal epithelium into cell columns oriented perpendicularly to the basal cell layer and by comparing the numbers and fractions of tritiated thymidine-labeled epithelial cells in the various cell columns and cell compartments.Before dietary supplementation with calcium, the profile of proliferating epithelial cells in the esophageal compartments in calcium group is similar to that in the placebo group, which is comparable to that previously observed in subjects with high risk for esophageal cancer. Seven months after supplementation having been started, in calcium group, proliferation was significantly reduced and the profile of the esophageal columns approached to that previously observed in subjects at low risk for esophageal cancer, however, in the placebo group, the proliferation and profile maintain at the same level as that before supplementation. Our findings indicate that oral calcium supplementation induces a more quiescent equilibrium in epithelial-cell proliferation in the esophageal mucosa of the subjects at high-risk for esophageal cancer, similar to that observed in subjects at low risk.

The main and added effects of heat on mortality in 33 Chinese cities from 2007 to 2013

Increases in ambient temperatures and the frequency of extreme heat events constitute important burdens on global public health.However,evidence on their effects on public health is limited and inconclusive in China.In this study,data on daily deaths recorded in 33 Chinese cities from 2007 to 2013 was used to evaluate the effect of heat on mortality in China.In addition to the definition of a heatwave established by the China Meteorological Administration,we combined four city-specific relative thresholds(90th,92.5th,95th,and 97.5th percentiles)of the daily mean temperature during the study period and three durations of≽2,≽3,and≽4 days,from which 13 heatwave definitions were developed.Then,we estimated the main and added effects of heat at the city level using a quasi-Poisson generalized additive model combined with a distributed lag nonlinear model.Next,the estimates for the effects were pooled at the national level using a multivariable meta-analysis.Subgroup analysis was performed according to sex,age,educational attainment,and spatially stratified heterogeneity.The results showed that the mortality risk increased from 22.3%to 37.1%due to the effects of the different heatwave definitions.The added effects were much lower,with the highest increase of 3.9%(95%CI:1.7%–6.1%)in mortality risk.Females,the elderly,populations with low educational levels,and populations living inland in China were found to be the most vulnerable to the detrimental effects of heat.These findings have important implications for the improvement of early warning systems for heatwaves.

Effective Force Stabilising Technique for the Immersed Boundary Method

The immersed boundary method has emerged as an efficient approach for the simulation of finite-sized solid particles in complex fluid flows.However,one of the well known shortcomings of the method is the limited support for the simulation of light particles,i.e.particles with a density lower than that of the surrounding fluid,both in terms of accuracy and numerical stability.Although a broad literature exists,with several authors reporting different approaches for improving the stability of the method,most of these attempts introduce extra complexities and are very costly from a computational point of view.In this work,we introduce an effective force stabilizing technique,allowing to extend the stability range of the method by filtering spurious oscillations arising when dealing with light-particles,pushing down the particle-to-fluid density ratio as low as 0.04.We thoroughly validate the method comparing with both experimental and numerical data available in literature.