Commensal microbiota in the digestive tract:a review of its roles in carcinogenesis and radiotherapy

The human microflora is a complex ecosystem composed of diverse microorganisms mainly distributed in the epidermal and mucosal habitats of the entire body,including the mouth,lung,intestines,skin,and vagina.These microbial communities are involved in many essential functions,such as metabolism,immunity,host nutrition,and diseases.Recent studies have focused on the microbiota associated with cancers,particularly the oral and intestinal microbiota.Radiotherapy,the most effective cytotoxic modality available for solid tumors,contributes to the treatment of cancer patients.Mounting evidence supports that the microbiota plays pivotal roles in the efficacy and prognosis of tumor radiotherapy.Here,we review current research on the microbiota and cancer development,and describe knowledge gaps in the study of radiotherapy and the microbiota.Better understanding of the effects of the microbiome in tumorigenesis and radiotherapy will shed light on future novel prevention and treatment strategies based on modulating the microbiome in cancer patients.

Variations of Raindrop Size Distribution and Radar Retrieval in Outer Rainbands of Typhoon Mangkhut(2018)

The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated.The observations by three two-dimensional video disdrometers deployed in central Guangdong Province were analyzed concurrently.It was found that the radial distribution of the median volume diameter(D_(0))and normalized intercept parameter(N_(w))varied in different stages,and that raindrops smaller than 3.0 mm contributed more than 99%of the total precipitation.Considering the characteristics of precipitation in the typhoon outer rainband,a modified stratiform rain(SR)-convective rain(CR)separator line is proposed based on D_(0) and N_(w) scatterplots.Meanwhile,an“S-C likelihood index”is introduced,which was used to classify three rain types(SR,CR,and mixed rain).The CR results were highly consistent with those of the improved typhoon precipitation classification method based on rain rate.By calculating effectively the radar reflectivity factor(Ze)in the Ku and Ka bands,D0-Ze and N_(w)-D_(0) empirical relations were thereby derived for improving the accuracy of rainfall retrieval.Among the four quantitative precipitation estimators using S-band dual-polarimetric radar parameters simulated by the T-matrix method,the estimator that adopted the specific differential phase and differential reflectivity was found to be the most effective for both SR and CR.