Dynamics and optimal control of tuberculosis model with the combined effects of vaccination, treatment and contaminated environments.

Tuberculosis has affected human beings for thousands of years, and until today, tuberculosis still ranks third among 29 infectious diseases in China. However, most of the existing mathematical models consider a single factor, which is not conducive to the study of tuberculosis transmission dynamics. Therefore, this study considers the combined effects of vaccination, treatment, and contaminated environments on tuberculosis, and builds a new model with seven compartments of $ SVEITRW $ based on China's tuberculosis data. The study shows that when the basic reproduction number $ R_{0} $ is less than 1, the disease will eventually disappear, but when $ R_{0} $ is greater than 1, the disease may persist. In the numerical analysis part, we use Markov-chain Monte-Carlo method to obtain the optimal parameters of the model. Through the next generation matrix theory, we calculate that the $ R_{0} $ value of tuberculosis in China is $ 2.1102 $, that is, if not controlled, tuberculosis in China will not disappear over time. At the same time, through partial rank correlation coefficients, we find the most sensitive parameter to the basic reproduction number $ R_{0} $. On this basis, we combine the actual prevalence of tuberculosis in China, apply Pontryagin's maximum principle, and perform cost-effectiveness analysis to obtain the conditions required for optimal control. The analysis shows that four control strategies could effectively reduce the prevalence of TB, and simultaneously controlling $ u_{2}, u_{3}, u_{4} $ is the most cost-effective control strategy.

Global trends and partial forecast of adverse effects of medical treatment from 1990 to 2019: an epidemiological analysis based on the global burden of disease study 2019.

BACKGROUND: The possibility of adverse effects of medical treatment (AEMT) is increasing worldwide, but little is known about AEMT in China. This study analyzed the health burden of AEMT in China in recent years through the Global Burden of Disease Study (GBD) 2019 and compared it with the worldwide average level and those in different sociodemographic index (SDI) regions. METHODS: We calculated the age-standardized rate (ASR) of deaths, disability-adjusted life years (DALYs), years of life lost (YLLs), years lived with disability (YLDs), incidence and prevalence attributed to AEMT in China, worldwide and countries with different sociodemographic indices during 1990-2019 using the latest data and methods from the GBD 2019. RESULTS: From 1990 to 2019, the global age-standardized death rate (ASDR), DALYs, and YLLs for AEMT showed a significant downward trend and were negatively associated with the SDI. By 2040, the ASDR is expected to reach approximately 1.58 (95% UI: 1.33-1.80). From 1990 to 2019, there was no significant change in the global incidence of AEMT. The occurrence of AEMT was related to sex, and the incidence of AEMT was greater among females. In addition, the incidence of AEMT-related injuries and burdens, such as ASR of DALYs, ASR of YLLs and ASR of YLDs, was greater among women than among men. Very old and very young people were more likely to be exposed to AEMT. CONCLUSIONS: From 1990 to 2019, progress was made worldwide in reducing the harm caused by AEMT. However, the incidence and prevalence of AEMT did not change significantly overall during this period. Therefore, the health sector should pay more attention to AEMT and take effective measures to reduce AEMT.

1,3,4-Oxadiazole Derivatives as Plant Activators for Controlling Plant Viral Diseases: Preparation and Assessment of the Effect of Auxiliaries.

Plant viral diseases cause the loss of millions of dollars to agriculture around the world annually. Therefore, the development of highly efficient, ultra-low-dosage agrochemicals is desirable for protecting the health of crops and ensuring food security. Herein, a series of 1,3,4-oxadiazole derivatives bearing an isopropanol amine moiety was prepared, and the inhibitory activity against tobacco mosaic virus (TMV) was assessed. Notably, compound A14 exhibited excellent anti-TMV protective activity with an EC50 value of 137.7 mg L-1, which was superior to that of ribavirin (590.0 mg L-1) and ningnanmycin (248.2 mg L-1). Moreover, the anti-TMV activity of some compounds could be further enhanced (by up to 5-30%) through supplementation with 0.1% auxiliaries. Biochemical assays suggested that compound A14 could suppress the biosynthesis of TMV and induce the plant's defense response. Given these merits, designed compounds had outstanding bioactivities and unusual action mechanisms and were promising candidates for controlling plant viral diseases.

Ozone Degradation of Prometryn in Ruditapes philippinarum: Response Surface Methodology Optimization and Toxicity Assessment.

ABSTRACT: This study optimized the method for ozone (O3) degradation of prometryn in the clam Ruditapes philippinarum and evaluated toxicity changes during ozone degradation. The gas chromatography method for the detection of prometryn was appropriately improved. The linear range was 5 to 500 ng/mL, with a correlation coefficient of 0.9964. The addition concentration of prometryn was 0.025 to 0.100 mg/kg, the recovery was 77.97 to 85.00%, the relative standard deviation (n = 6) was 2.36 to 7.86%, and the limit of detection was 0.3 µg/kg. Using the central composite design in two experiments, ozone as gas and ozone dissolved in water, the effect of degradation rate was studied on three variables: ozone concentration, temperature, and exposure time. Ozone as gas and ozone dissolved in water have the same degradation effect on prometryn. The O3 concentration was 4.2 mg/L, the temperature was 40°C, the exposure time was 10 min, and the maximum degradation rate was 89.94 and 89.69% for the two experiments, respectively. In addition, the toxicity of ozone degradation products was evaluated using buffalo rat liver cells. After ozone treatment for 30 min, the toxicity of the ozone degradation products was reduced to 52.15% compared with that of prometryn itself. The toxicity of the ozone degradation products increased slightly when the ozonation time was prolonged; the toxicity at 180 min was greater than that of the parent compound prometryn. Overall, the application of ozone degradation of pesticide residues is a promising new technology. This study determined better degradation conditions for prometryn in R. philippinarum and also provided a theoretical basis for the widespread use of ozone technology in the future.

Modeling the Effects of Meteorological Factors and Unreported Cases on Seasonal Influenza Outbreaks in Gansu Province, China.

Influenza usually breaks out seasonally in temperate regions, especially in winter, infection rates and mortality rates of influenza increase significantly, which means that dry air and cold temperatures accelerate the spread of influenza viruses. However, the meteorological factors that lead to seasonal influenza outbreaks and how these meteorological factors play a decisive role in influenza transmission remain unclear. During the epidemic of infectious diseases, the neglect of unreported cases leads to an underestimation of infection rates and basic reproduction number. In this paper, we propose a new non-autonomous periodic differential equation model with meteorological factors including unreported cases. First, the basic reproduction number is obtained and the global asymptotic stability of the disease-free periodic solution is proved. Furthermore, the existence of periodic solutions and the uniformly persistence of the model are demonstrated. Second, the best-fit parameter values in our model are identified by the MCMC algorithm on the basis of the influenza data in Gansu province, China. We also estimate that the basic reproduction number is 1.2288 (95% CI:(1.2287, 1.2289)). Then, to determine the key parameters of the model, uncertainty and sensitivity analysis are explored. Finally, our results show that influenza is more likely to spread in low temperature, low humidity and low precipitation environments. Temperature is a more important factor than relative humidity and precipitation during the influenza epidemic. In addition, our results also show that there are far more unreported cases than reported cases.

Degradation of prometryn in Ruditapes philippinarum using ozonation: Influencing factors, degradation mechanism, pathway and toxicity assessment.

In recent years, prometryn was utilized as watergrass remover in the aquaculture industry, resulting in the accumulated residual in the aquatic products. The present study focuses on the ozone degradation of prometryn in the Ruditapes philippinarum. The ozone concentration in water increased along with the injection time (60min). The contents of hydroxyl (·OH) and superoxide (O2·-) radicals increased along with the ozone injection time. The effects of temperature, pH, prometryn initial concentration and ozone concentration on the removal efficiency of prometryn were evaluated. The maximum removal efficiency of 86.12% was obtained under the conditions of pH 7, prometryn initial concentration 0.05 mg/kg and the ozone concentration 4.2 mg/L at 28 °C for 30 min. Ion chromatography (IC) and Fourier transform infrared (FT-IR) spectroscopy results show that the S and N atoms in the outer layer of the triazine ring during the prometryn degradation process were oxidized and removed. A total of 30 intermediate compounds were identified using the gas chromatography-mass spectrometry (GC-MS) method. Combined with the IC and FT-IR results, three possible degradation pathways of prometryn were proposed. The prometryn was finally degraded into some small molecules with reduced toxicity by 63.16% for 120 min ozonization treatment. Overall, our work provides a novel approach for prometryn degradation in Ruditapes philippinarum, which can be extended for removing the residues of agricultural and veterinary drugs in other aquatic products.

Comparison of Efficacy and Economic Value of Prandilin 25 and Humalog Mix 25 in Patients with Newly Diagnosed Type 2 Diabetes by a Continuous Glucose Monitoring System.

INTRODUCTION: To determine the clinical efficacy and economic value of insulin lispro 25-Prandilin 25 vs. insulin lispro 25-Humalog mix 25 in treatment of newly diagnosed type 2 diabetes mellitus (T2DM) by a continuous glucose monitoring system (CGMS). METHODS: This was a single-center, randomized, case-crossover clinical trial. Participants were randomly allocated to two groups and underwent two kinds of insulin lispro 25 treatment separated by a 1-day washout period. In total, 81 patients with newly diagnosed T2DM with hemoglobin A1c (HbA1c) above 9% were hospitalized and randomly divided to receive Prandilin 25/Humalog mix 25 or Humalog mix 25/Prandilin 25 treatment. All participants were subjected to metformin therapy simultaneously. Glycemic control was reached after 7-8 days Prandilin 25 or Humalog mix 25 treatment; each patient received continuous glucose monitoring (CGM) for 5 consecutive days (from day 1 to day 5). On day 3 of CGM performance, Prandilin 25 treatment was switched to Humalog mix 25 treatment at the same dosage or vice versa. Parameters representing glycemic variability (GV) and postprandial glucose excursions, including 24-h mean blood glucose (24hMBG), 24-h standard deviation of blood glucose (24hSDBG), 24-h mean amplitude of glycemic excursion (24hMAGE), large amplitude of glycemic excursion (LAGE), incremental area under the curve (AUC) for different glucose levels, and postmeal relative areas under the CGM curve (AUCpp) for 1-4 h of each meal, were calculated for each patient. RESULTS: No significant differences were found in the 24hMAGE, 24hMBG, 24hSDBG, LAGE, mean 1-h preprandial blood glucose and the incidence of hypoglycemia between the Prandilin 25 treatment group and Humalog mix 25 treatment group. Similarly, there were no between-treatment differences for AUC and time when blood glucose was below 3.9 mmol/l, between 3.9 mmol/l and 10.0 mmol/l, or above 10.0 mmol/l. Further analysis showed the AUCpp for 1-4 h of each meal for two kinds of treatments were similar. However, the mean estimated cost of Prandilin 25 was only 85% of Humalog mix 25 in one treatment course. CONCLUSION: Prandilin 25 is non-inferior in clinical efficacy compared with Humalog mix 25. In view of the significant difference in the cost of the two kinds of insulin lispro 25, Prandilin 25 is a much more cost-effective anti-diabetes drug for management of T2DM. TRIAL REGISTRATION: Chinese Clinical Trial Register identifier, ChiCTR1800015829.

Ultrasound Assessment of Intima-media Thickness and Diameter of Carotid Arteries in Patients Undergoing Hemodialysis or Renal Transplantation.

Renal transplant (RT) recipients have a high risk of developing cardiovascular diseases. However, the effects of renal transplantation on the development of arteriosclerosis have been controversial. The carotid intima-media thickness (СШТ) and diameter (CD) are important indicators of vascular remodeling and arteriosclerosis. In this study, 31 patients with hemodialysis (HD), 31 RT recipients and 84 age- and gender-matched control subjects were enrolled. Their CIMT and CD were measured by ultrasonic radiofrequency tracking, and the linear regression models and Z test were used to identify the progression of arteriosclerosis and the risk factors. Compared with HD group, RT group had significantly lower CIMT and CD. CIMT was found to be associated with age, body weight, resistance index and diastolic velocity, while CD was associated significantly with age, body weight, pulsatility index, end diastolic velocity and diastolic blood pressure (DBP), respectively. The correlation curves between CIMT and age showed the slopes of curves were decreased successively in control, RT and HD groups, and the curves between CD and age showed the slopes were decreased in order of RT > control > HD groups. It was concluded that CIMT and CD were significantly correlated with age in RT and moderately with age in HD patients. RT could reduce the progress of arteriosclerosis in patients with end-stage renal disease.

COMPARISON OF ORGAN DOSES IN HUMAN PHANTOMS: VARIATIONS DUE TO BODY SIZE AND POSTURE.

Organ dose calculations performed using human phantoms can provide estimates of astronauts' health risks due to cosmic radiation. However, the characteristics of such phantoms strongly affect the estimation precision. To investigate organ dose variations with body size and posture in human phantoms, a non-uniform rational B-spline boundary surfaces model was constructed based on cryosection images. This model was used to establish four phantoms with different body size and posture parameters, whose organs parameters were changed simultaneously and which were voxelised with 4 × 4 × 4 mm3 resolution. Then, using Monte Carlo transport code, the organ doses caused by ≤500 MeV isotropic incident protons were calculated. The dose variations due to body size differences within a certain range were negligible, and the doses received in crouching and standing-up postures were similar. Therefore, a standard Chinese phantom could be established, and posture changes cannot effectively protect astronauts during solar particle events.

Assessment of flavonoids and volatile compounds in tea infusions of water lily flowers and their antioxidant activities.

Water lily, a member of the Nymphaeaceae family, can be made into tea on the basis of outstanding fragrance characteristics and health care functions. In this study, 16 flavonoids were identified and quantified in tea infusions prepared from the petals of 33 water lily cultivars using HPLC-DAD and HPLC-ESI-MS/MS. The infusions were analyzed with HS-SPME coupled with GC-MS; 29 volatile compounds were detected, of which nine were found to be scent components. The cultivars were clustered into three clusters characterized according to scent components. The 'Conqueror' and 'Virginia' cultivars had the highest antioxidant activities. The concentrations of polyphenols and flavonoids showed significant positive correlations with antioxidant activity as measured by DPPH, ABTS(+), and FRAP assays. This study is valuable for a fuller understanding of this important tea and can also be used for the development of water lily.

Systematic qualitative and quantitative assessment of fatty acids in the seeds of 60 tree peony (Paeonia section Moutan DC.) cultivars by GC-MS.

Seeds from Paeonia ostii and Paeoniarockii have been recently identified as novel resources of α-linolenic acid (ALA) in China. To assess whether tree peony cultivars can be used as oil resource, fatty acids (FAs) in 60 cultivars were monitored and evaluated in this study. The results indicated that the composition and content of FAs varied dramatically among different cultivars, in which ALA, linoleic acid, oleic acid, palmitic acid, and stearic acid were the dominant. The 60 cultivars were classified into six clusters by hierarchical cluster analysis, and they were quite distinct from each other. Finally, six cultivars with high yield and high quality were screened out, comprising of 'Liuliguanzhu', 'Hongguanyupei', 'LSS-2', 'LSS-1', 'Jingshenhuanfa' and 'LSS-11'. These cultivars were appropriately applied in practical oil production. Overall, tree peony oil with abundant unsaturated fatty acids especially ALA was proved to be a top-grade source for edible oil and nutritional supplements.

The complex fluctuations of probabilistic Boolean networks.

Probabilistic Boolean networks (PBNs) are extensions of Boolean networks (BNs), and both have been widely used to model biological systems. In this paper, we study the long-range correlations of PBNs based on their corresponding Markov chains. PBN states are quantified by the deviation of their steady-state distributions. The results demonstrate that, compared with BNs, PBNs can exhibit these dynamics over a wider and higher noise range. In addition, the constituent BNs significantly impact the generation of 1/f dynamics of PBNs, and PBNs with homogeneous steady-state distributions tend to sustain the 1/f dynamics over a wider noise range.

Onartuzumab (MetMAb): using nonclinical pharmacokinetic and concentration-effect data to support clinical development.

PURPOSE: We characterized the pharmacokinetics of onartuzumab (MetMAb) in animals and determined a concentration-effect relationship in tumor-bearing mice to enable estimation of clinical pharmacokinetics and target doses. EXPERIMENTAL DESIGN: A tumor growth inhibition model was used to estimate tumoristatic concentrations (TSC) in mice. Human pharmacokinetic parameters were projected from pharmacokinetics in cynomolgus monkeys by the species-invariant time method. Monte Carlo simulations predicted the percentage of patients achieving steady-state trough serum concentrations (Ctrough ss) ≥TSC for every 3-week (Q3W) dosing. RESULTS: Onartuzumab clearance (CL) in the linear dose range was 21.1 and 12.2 mL/d/kg in mice and cynomolgus monkeys with elimination half-life at 6.10 and 3.37 days, respectively. The estimated TSC in KP4 pancreatic xenograft tumor-bearing mice was 15 µg/mL. Projected CL for humans in the linear dose range was 5.74 to 9.36 mL/d/kg with scaling exponents of CL at 0.75 to 0.9. Monte Carlo simulations projected a Q3W dose of 10 to 30 mg/kg to achieve Ctrough ss of 15 µg/mL in 95% or more of patients. CONCLUSIONS: Onartuzumab pharmacokinetics differed from typical bivalent glycosylated monoclonal antibodies with approximately 2-times faster CL in the linear dose range. Despite this higher CL, xenograft efficacy data supported dose flexibility with Q1W to Q3W dose regimens in the clinical setting with a TSC of 15 µg/mL as the Ctrough ss target. The projected human efficacious dose of 10 to 30 mg/kg Q3W should achieve the target TSC of 15 µg/mL. These data show effective pharmacokinetic/pharmacodynamic modeling to project doses to be tested in the clinic.

[Analysis on research projects for acupuncture and moxibustion supported by NSFC during the 11th 5-year-plan].

In the present paper, the authors introduce the approved and finished research projects for acupuncture and moxibustion therapies supported by the National Natural Science Foundation of China (NSFC) during the 11th 5-year-plan. A total of 194 research projects were subsidized by NSFC from 2006 to 2010. These projects include 6 aspects: meridian-collaterals, acupoint theory, acupuncture analgesia, mechanisms underlying improvement of different clinical problems, clinical trials, and moxibustion therapy. The research on acupoints has been becoming a new hotspot in recent years. Majority of the research projects focus on the mechanism of acu-moxibustion underlying improvement of different clinical problems, while fewer projects on clinical trials. During the 11th 5-year-plan, 119 projects were completed; most of them involved meridian-collateral theory, acupoint theory, mechanism of acu-moxibustion underlying improvement of clinical problems and acupuncture manipulations. Following analysis of the finished research projects, we find that 1) many neurobiological methods and techniques are commonly used in the research on meridian-collateral theory; 2) the research on acupoint theory is changing from observing the local morphological structure to identifying characteristics of the regional activated receptors, particularly under the circumstances of visceral pathological conditions and efficacies of acupoints; 3) researches on the underlying mechanism of acu-moxibusiton for improving clinical disorders mainly focused on its cerebral protective effects against cerebral ischemia, in addition, researches about other diseases on clinical conditions have been also carried out, but the related mechanisms are far from understanding; 4) In many research projects, various new methods and techniques, such as fMRI, position emission tomography, genomics, proteomics, molecular biology, nerve stem cell, etc. were widely used; 5) Randomized controlled multi-center clinical trials are definitely insufficient. Only two clinical projects were finished during the 11th 5-year-plan. Moreover, it should be noted that in the subject of acu-moxibustion, independent innovation researches are fewer; the foundation of competitive ability is relatively weaker; the supporting conditions for finishing the research projects are poorer in some institutes or districts; and the interrelations among the theoretical, experimental and clinical researches are not intimately close, leading to relative lag in the subject development.

[Construction and biological assessment of tissue engineering intervertebral disc].

OBJECTIVE: To investigate the value of bone marrow-mesenchymal stem cells (BM-MSCs) transformed by nucleus pulposus (NPs) for construction of tissue engineering disc. METHODS: BM-MSCs and fetal NPs were cultured in vitro, planted on polylactic acid-polyglycolic acid copolymer (PLGA), and observed with inverted microscope and scanning electronic microscope. PLGA scaffolds with adherent BM-MSCs and NPs, as well as BM-MSCs and NPs suspension were implanted into intervertebral discs of New Zealand white rabbits, respectively. Intervertebral signal intensity was evaluated by Thompson grading 12 weeks later. Proteoglycan and type IIcollagen were determined by spectrophotometric method and immunohistochemistry, respectively. RESULTS: Spindle or multi-angular BM-MSCs turned into fibro-like phenotype coculture of BM-MSCs and NPs, which grew well with normal morphology when they attached on PLGA scaffolds. There was statistical difference in intervertebral signal intensity, and the expression of proteoglycan and type IIcollagen between PLGA scaffolds group and control group (P < 0.05), the content of proteoglycan was (3.93 ± 0.31) mg/100 mg in the PLGA scaffolds group whereas (3.52 ± 0.26) mg/100 mg in the control group. CONCLUSIONS: BM-MSCs can be induced into NPs by cocultivation, and PLGA scaffolds can provide good growing conditions, and maintain high mechanical properties and spacial structure which meet the requirement of tissue engineering disc to prevent degeneration.

Assessment of the determination of azodicarbonamide and its decomposition product semicarbazide: investigation of variation in flour and flour products.

Azodicarbonamide, as a bleaching agent and improving agent, is a permitted food additive in certain countries and can be determined by high-performance liquid chromatography. However, it partially degrades with the heat of processing to form trace amounts of semicarbazide, which shows carcinogenicity and also has been shown to cause tumors. The concentration of semicarbazide in azodicarbonamide-treated flour was determined by isotope dilution ((13)C, (15)N(2)-semicarbazide) liquid chromatography electrospray tandem mass spectrometry (LC-MS/MS). The quantification was obtained utilizing the homologous internal standard. The limits of detection were 1 mg/kg for azodicarbonamide and 0.5 × 10(-3) mg/kg for semicarbazide. The rates of recovery were 82.3-103.1% for azodicarbonamide and 72.4-116.5% for semicarbazide. This study prepared four different types of flour products to investigate the variation of semicarbazide. The concentration of semicarbazide in all types of flour products is higher than that in flour, and the concentration of semicarbazide in outside of flour products is slightly higher than that in the inside. As the problem of food safety hazard aggravates daily, we should be more concerned about food security and human health.

Assessment of glomerular filtration rate by serum cystatin C in patients undergoing coronary artery bypass grafting.

BACKGROUND: Assessment of renal function in patients undergoing coronary artery bypass grafting (CABG) is important. Cystatin C has been proposed as an improved indicator of renal function. The aim of this study was to assess cystatin C as an early marker of changes in glomerular filtration rate (GFR) after CABG. METHODS: Blood samples were collected from 61 CABG patients at different time points. Using (51)Cr-ethylenediaminetetraacetic acid ((51)Cr-EDTA) clearance as a 'gold standard', we compared the correlations and non-parametric receiver operator characteristic curves of serum cystatin C, serum creatinine and 24 h creatinine clearance (Ccr). RESULTS: The inverse of cystatin C correlated better with (51)Cr-EDTA than those of serum creatinine and Ccr (r = 0.8578, 0.6771 and 0.6929, respectively). Cystatin C exhibited significantly superior diagnostic accuracy for detecting GFR <80 mL/min/1.73 m(2) compared with serum creatinine (P = 0.013) and Ccr (P = 0.025); for detecting GFR <60 mL/min/1.73 m(2), cystatin C had similar diagnostic accuracy to Ccr (P = 0.812) but was superior to creatinine (P = 0.033). At the best cut-off value, cystatin C had sensitivity 89% and specificity 93% for detecting GFR <80 mL/min/1.73 m(2), sensitivity 86% and specificity 96% for detecting GFR <60 mL/min/1.73 m(2). CONCLUSIONS: Cystatin C is a better marker for detecting small temporary changes of GFR in CABG patients. This may allow better identification of patients with renal impairment.

[Roles of risk assessment and Ki-67 index in judging prognostic of gastrointestinal stromal tumors].

OBJECTIVE: To investigate the roles of risk assessment and Ki-67 index in judging prognostic of gastrointestinal stromal tumors (GISTs). METHODS: The clinical data of 102 patients of GIST, 60 with gastric stromal tumor and 42 with small intestinal stromal tumor were collected. The relations of disease free survival rate and disease specific overall survival rate to Ki-67 index and risk assessment were analyzed. RESULTS: Risk assessment showed that 2 cases were at very low risk, 14 at low risk, 16 at intermediate risk, and 28 at high risk. As classified by the Ki-67 index system, 13 cases were in the group of Ki-67 index > or =5%, and the other 47 cases were in the group of Ki-67 index <5%. The patients with high risk or Ki-67 index > or =5% had significantly lower disease-free survival rates (Pki-67 = 0.001, P risk assessment = 0.044) and disease specific overall survival rates (Pki-67 = 0.001, P risk assessment = 0.007). The high-risk patients had significantly lower survival rate than the patients of other grades (P disease-free = 0.044, P over all = 0.012). In the 42 patients with small intestinal stromal tumor 9 were at low risk, 11 at intermediate risk, and 22 at high risk;and there were 12 cases with Ki-67 index > or =5% and 30 cases with Ki-67 index <5%. Risk assessment had no relationship with disease specific overall survival rate. The overall survival rate of the intestinal stromal tumor patients with the Ki-67 index > or =5% was significantly lower than that of those with the K-67 index <5% (P = 0.039), however, Ki-67 index was not related to disease free survival rate. Four of the gastric stromal tumor patients at low and intermediate risk and with Ki-67 index > or =5% suffered recurrence or metastasis; and 2 similar cases were found in the small intestinal stromal tumor cases. CONCLUSION: Risk assessment and Ki-67 index are good prognostic indicators for gastric stromal tumors. In small intestinal stromal tumors, risk assessment is only related to disease free survival rate, and Ki-67 index is related to disease specific overall survival rate. In the GIST patients at low and intermediate risk, Ki-67 can be a good complimentary indicator to predict the recurrence or metastasis.

Build-up and surface dose measurements on phantoms using micro-MOSFET in 6 and 10 MV x-ray beams and comparisons with Monte Carlo calculations.

This work is intended to investigate the application and accuracy of micro-MOSFET for superficial dose measurement under clinically used MV x-ray beams. Dose response of micro-MOSFET in the build-up region and on surface under MV x-ray beams were measured and compared to Monte Carlo calculations. First, percentage-depth-doses were measured with micro-MOSFET under 6 and 10 MV beams of normal incidence onto a flat solid water phantom. Micro-MOSFET data were compared with the measurements from a parallel plate ionization chamber and Monte Carlo dose calculation in the build-up region. Then, percentage-depth-doses were measured for oblique beams at 0 degrees-80 degrees onto the flat solid water phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm below the surface. Measurements were compared to Monte Carlo calculations under these settings. Finally, measurements were performed with micro-MOSFET embedded in the first 1 mm layer of bolus placed on a flat phantom and a curved phantom of semi-cylindrical shape. Results were compared to superficial dose calculated from Monte Carlo for a 2 mm thin layer that extends from the surface to a depth of 2 mm. Results were (1) Comparison of measurements with MC calculation in the build-up region showed that micro-MOSFET has a water-equivalence thickness (WET) of 0.87 mm for 6 MV beam and 0.99 mm for 10 MV beam from the flat side, and a WET of 0.72 mm for 6 MV beam and 0.76 mm for 10 MV beam from the epoxy side. (2) For normal beam incidences, percentage depth dose agree within 3%-5% among micro-MOSFET measurements, parallel-plate ionization chamber measurements, and MC calculations. (3) For oblique incidence on the flat phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm, measurements were consistent with MC calculations within a typical uncertainty of 3%-5%. (4) For oblique incidence on the flat phantom and a curved-surface phantom, measurements with micro-MOSFET placed at 1.0 mm agrees with the MC calculation within 6%, including uncertainties of micro-MOSFET measurements of 2%-3% (1 standard deviation), MOSFET angular dependence of 3.0%-3.5%, and 1%-2% systematical error due to phantom setup geometry asymmetry. Micro-MOSFET can be used for skin dose measurements in 6 and 10 MV beams with an estimated accuracy of +/- 6%.

Strategy formulation for schistosomiasis japonica control in different environmental settings supported by spatial analysis: a case study from China.

With the aim of exploring the usefulness of spatial analysis in the formulation of a strategy for schistosomiasis japonica control in different environmental settings, a population-based database was established in Dangtu county, China. This database, containing the human prevalence of schistosomiasis at the village level from 2001 to 2004, was analyzed by directional trend analysis supported with ArcGIS 9.0 to select the optimum predictive approach. Based on the approach selected, different strata of prevalence were classified and the spatial distribution of human infection with Schistosoma japonicum was estimated. The second-order ordinary kriging approach of spatial analysis was found to be optimal for prediction of human prevalence of S. japonicum infection. The mean prediction error was close to 0 and the root-mean-square standardised error was close to 1. Starting with the different environmental settings for each stratum of transmission, four areas were classified according to human prevalence, and different strategies to control transmission of schistosomiasis were put forward. We conclude that the approach to use spatial analysis as a tool to predict the spatial distribution of human prevalence of S. japonicum infection improves the formulation of strategies for schistosomiasis control in different environmental settings at the county level.