Technical note: Evaluation of the dose enhancement effect for a novel transmission-type x-ray tube using the Monte Carlo method.

PURPOSE: Transmission-target x-ray tubes generate more x-rays than reflection thick-target x-ray tubes. A transmission x-ray tube combined with radiosensitizers has a better radiation enhancement effect. This study investigated the feasibility of using a transmission x-ray tube with radiosensitizers in clinical radiotherapy and its effect on radiation dose enhancement. METHODS: This study used MCNP6.2 to simulate the model of a transmission x-ray tube and Co-60 beam.   The radiation enhancement effect of radiosensitizers was examined with iodine-127 (I-127), radioiodinated iododeoxyuridine (IUdR), and gold nanoparticles (GNPs). RESULTS: The study results showed that the dose enhancement factor (DEF) of the transmission x-ray tube with GNPs was 10.27, which was higher than that of I-127 (6.46) and IUdR (3.08). The DEF of the Co-60 beam with GNPs, I-127, and IUdR was 1.23, 1.19, and 1.2, respectively. The Auger electron flux of the transmission x-ray tube with GNPs was 1.19E+05 particles/cm2 . CONCLUSIONS: This study found that a transmission x-ray tube with appropriate radiosensitizers could produce a high rate of Auger electrons to fulfill the radiation enhancement effect, and this procedure has the potential to become a radiotherapy modality.

Integrated assessment of differentially expressed plasma microRNAs in subtypes of nonsyndromic orofacial clefts.

BACKGROUND: Orofacial clefts include cleft lip only (CLO), cleft palate only (CPO), and cleft lip with palate (CLP). Previously, we reported the expression profile of plasma microRNAs in CLO, CPO, and CLP, respectively. However, the interaction of each subtype remains poorly investigated. METHODS: In this study, we integrated the expression profiles of plasma miRNAs in these 3 subtypes, and assessed the distinct and overlapping dysregulated miRNAs using Venn diagrams. Their respective target genes reported in the literature were further analyzed using pathway analysis. RESULTS AND CONCLUSION: The results showed that distinct or overlapping signaling pathways were involved in CLO, CPO, and CLP. The common key gene targets reflected functional relationships to the Wnt, Notch, TGF-beta, and Hedgehog signaling pathways. Further studies should examine the mechanism of the potential target genes, which may provide new avenues for future clinical prevention and therapy.

Exposure inequality assessment for PM2.5 and the potential association with environmental health in Beijing.

Fine particulate matter (PM2.5) pollution exposure has an adverse impact on public health, and some vulnerable social groups suffer from unfair exposure. Few studies have been conducted to estimate and to compare the exposure and inequality of different residential demographics at multiple time scales. This study assessed the exposures level of age and education subgroups on the whole city and the exposure inequalities of these subgroups within a concentration interval area for PM2.5 pollution at multiple time scales in Beijing in 2015. The potential association of PM2.5 with cancer morbidity was also explored through spatial analysis. Comparing the model performance of the ordinary kriging (OK) interpolation method with that of the land use regression (LUR) model method, the OK method was applied to estimate the PM2.5 concentrations at 1 km resolution. The exposure and inequality assessments for PM2.5 pollution were conducted by calculating the population-weighted exposure level and the inequality index, respectively. The spatial correlation of PM2.5 with cancer morbidity was investigated by spatial autocorrelation and grey correlation degree analysis. Overall, for the highest 1-h concentration, older people (age ≥ 60) and residents with tertiary education were the most disproportionately exposed to PM2.5. For the higher PM2.5 concentration during the annual average, spring, autumn and winter periods, exposures to PM2.5 were disproportionately high for children (age ≤ 4) and residents with primary or secondary education. Moreover, exposures to PM2.5 were disproportionately low for the illiterate due to their geographical distribution characteristics. Additionally, the spatial distribution of cancer morbidity was similar to the spatial pattern of PM2.5, manifesting a potential spatial association between PM2.5 and cancer morbidity. These findings provide scientific support for air pollution exposure assessments and environmental epidemiology.

[Effects of nitrogen application on canopy vertical structure, grain-leaf ratio and economic benefit of winter wheat under drip irrigation.] / æ–½æ°®é‡å¯¹æ»´çŒå†¬å°éº¦å† å±‚åž‚ç›´ç»“æž„ç‰¹å¾ã€ç²’å¶æ¯”åŠç»æµŽæ•ˆç›Šçš„å½±å“.

To optimize the fertilization rate of winter wheat under drip irrigation in Xinjiang region, a field investigation was carried out to assess effects of nitrogen (N) applications on canopy vertical structure, grain-leaf ratio, yield and economic benefit of winter wheat. Four rates of nitrogen application, 0 kg·hm-2(N0), 104 kg·hm-2(N1), 173 kg·hm-2(N2) and 242 kg·hm-2(N3) were set in a randomized block experimental design. Meantime, leaf and stem morphological characters, canopy temperature and humidity in flowering stage, grain-leaf area ratio, yield and yield components, economic benefits of winter wheat were observed under different treatments. The results showed that the leaf length and width at different positions of wheat under the nitrogen fertilization treatments were significantly higher than that without nitrogen fertilization (P<0.05), and plant height ranged from 65.57 to 81.58 cm. With an increasing rate of nitrogen fertilization, both leafarea index and stem diameter presented a trend of first increasing and then decreasing, and reached the maximum under N2 treatment, which was 5.48 and 0.49 cm, respectively. Diurnal variation of canopy temperature and humidity were "convex" and "concave" shape, followed an order of N0>N1>N2>N3 in temperature, but reversely in canopy humidity. The duration of high temperature higher than 35 ℃ were shorten 1 hour to 3.5 hours as the nitrogen application level increased, and there was significant difference between N1 and N3 on grain-leaf ratio. Yield and economic be-nefit decreased initially and then increased with increasing nitrogen application. Yield and economic benefit of treatment N2 were 32.8% and 77.7% higher than those of treatment N0, 12.6% and 5.4% higher than those of treatment N1, and 5.2% and 4.2% higher than those of treatment N3, respectively. These results indicated that nitrogen application at about 173 kg·hm-2 could be recommended as the optimum rate for winter wheat, which had good leaf and plant morphology, appropriate canopy temperature and humidity, high yield and economic efficiency in the experiment area.

Changes in drug prescription utilization for diabetic and hypertensive outpatients after initiation of the National Health Insurance's Global Budget Program in Taiwan.

BACKGROUND: To examine changes in medicine utilization and prescription trends for diabetic (DM) and hypertensive (HT) patients upon initiation of the National Health Insurance (NHI) global budget (GB) program in Taiwan. MATERIAL/METHODS: Data on hospital-based outpatient prescriptions for DM and HT from the Taipei branch before and after the GB were analyzed from January 2002 to December 2004. A secondary analysis of reimbursed data, with descriptive and trend analyses of the four indicators, daily oral medication cost, daily tablets used, medicine items per prescription, and tablet cost, was conducted. RESULTS: The comparisons of before and after the GB were as follows: Daily oral medication cost increased from US $0.585 to $0.956 (64%) for the DM group and from $1.01 to $1.07 (6.12%) for the HT group. The increments for daily used tablets, medicine items per prescription, and tablet cost were 33.3%, 17.9%, and 26.5% for the DM group and 6.65%, 3.31%, and 0.27% for the HT group. Indicators for the DM group not only increased significantly compared with those of the HT group, but also had higher adjusted beta coefficients. The comparisons of before and after the GB showed that the increments for the DM group decreased slightly, but not those for the HT group. CONCLUSIONS: The indicators for DM were significantly higher than those of HT group during the implementation phase of the GB. The GB program implemented by the NHI in Taiwan slightly slowed the trend of hospital-based ambulatory prescription costs of DM, but not HT.