[Spatial autocorrelation and related factors of stroke mortality in Zhejiang Province based on spatial panel model in 2015-2020].

Objective: To explore the spatial autocorrelation and macro influencing factors of stroke mortality in Zhejiang Province in 2015-2020 and provide a scientific basis for stroke prevention and control strategy. Methods: The data on stroke death were obtained from Zhejiang Chronic Disease Surveillance System. The spatial distribution of stroke mortality was explored by mapping and spatial autocorrelation analysis. The spatial panel model analyzed the correlation between stroke mortality and socioeconomic and healthcare factors. Results: From 2015 to 2020, the average stroke mortality was 68.38/100 thousand. The standard mortality of stroke was high in the areas of east and low in the west, high in the south and low in the north. Moreover, positive spatial autocorrelation was observed (Moran's I=0.274-0.390, P<0.001). Standard mortality of stroke was negatively associated with per capita gross domestic product (GDP) (ß=-0.370, P<0.001), per capita health expenditure (ß=-0.116, P=0.021), number of beds per thousand population (ß=-0.161, P=0.030). Standard mortality of ischemic stroke was negatively associated with per capita GDP (ß=-0.310, P=0.002) and standard management rate of hypertension (ß=-0.462, P=0.011). Standard mortality of hemorrhagic stroke was negatively associated with per capita GDP (ß=-0.481, P<0.001), per capita health expenditure (ß=-0.184, P=0.001), number of beds per thousand population (ß=-0.288, P=0.001) and standard management rate of hypertension (ß=-0.336, P=0.029). Conclusions: A positive spatial correlation existed between stroke mortality in Zhejiang Province in 2015-2020. We must focus more on preventing and controlling strokes in relatively backward economic areas. Moreover, to reduce the mortality of stroke, increasing the investment of government medical and health funds, optimizing the allocation of medical resources, and improving the standard management rate of hypertension are important measures.

[Considerations for the development of adult vaccination in China].

Adult vaccination is an important component of the life-course immunization for all. Strengthening adult vaccination in China contributes to shrinking immunization gaps between regions and groups, enhancing the overall immunity of our population, and promoting health equity and social prosperity. Chinese adults bear the heavy burden of vaccine preventable diseases such as influenza, pneumococcal diseases and shingles, and have low coverage of vaccines against those diseases, so it is necessary to make efforts to improve adult vaccination development. This article focuses on elaborating the values of adult vaccination, introducing the current status of adult vaccination abroad, and analyzing the challenges and existing foundations for China to provide adult vaccination, and makes suggestions for the building and development of adult vaccination.

[A cross-sectional study on economic burden of pulmonary tuberculosis cases from designated tuberculosis hospital].

Objective: To understand the medical expenditure and related household economic burden of pulmonary tuberculosis (TB) patients receiving full course treatment in designated TB hospitals in China and identify the related factors. Method: A cross-sectional study was conducted in 535 consecutive TB patients receiving TB treatment from April 2017 to June 2017 in 5 designated TB hospitals in eastern and western China selected through stratified cluster sampling. A questionnaire was used to collect the information about patients' social economic characteristics and TB diagnosis and treatment expenditure. Results: The average total medical expenditure for TB treatment was 12 635.5 yuan (RMB), in which the direct medical expenditure accounted for 65.3% of the total. Nearly half of the total medical expenditure occurred in pre-treatment period. The expenditure in pre- treatment period was higher in the patients with low education level, newly treated patients, and initial sputum negative patients. The median (quartile) for the ratio of total medical expenditure to annual household income was 22%(10%-57%). Ordinal logistic regression analysis showed that low-level education background, lower household income, hospitalization and suffering from other chronic disease might increase the ratio of medical expenditure to annual household income. Conclusions: Medical expenditure for full course TB treatment is still high in patients in designated TB hospitals. It is suggested to strengthen the capability building of timely found and referral of TB patients in non- designated hospitals and improve fee reduction and exemption policy for some patients.

[Construction and use of big data for health management].

Population-based lifetime health services rely on health management practice. Collection, management and analysis of big data are highly suitable for the huge population base in China. Nowadays, more and more research focus on the methods, security and ethnicity of health management and big data, and a plenty of instructive results have been made, which could be used to guide the future practice and development. Yichang mode has set a precedent for construction and use of big data for health management.

Trabecular microstructure is influenced by race and sex in Black and White young adults.

Lower fracture rates in Black men and women compared to their White counterparts are incompletely understood. High-resolution imaging specific to trabecular bone may provide insight. Black participants have enhanced trabecular morphology. These differences may contribute to the lower fracture risk in Black versus White individuals. INTRODUCTION: Lower fracture rates in Black men and women compared to their White counterparts may be explained by favorable bone microstructure in Black individuals. Individual trabecular segmentation (ITS) analysis, which characterizes the alignment and plate- and rod-like nature of trabecular bone using high-resolution peripheral quantitative computed tomography (HR-pQCT), may provide insight into trabecular differences by race/ethnic origin. PURPOSE: We determined differences in trabecular bone microarchitecture, connectivity, and alignment according to race/ethnic origin and sex in young adults. METHODS: We analyzed HR-pQCT scans of 184 adult (24.2 ± 3.4 years) women (n = 51 Black, n = 50 White) and men (n = 34 Black, n = 49 White). We used ANCOVA to compare bone outcomes, and adjusted for age, height, and weight. RESULTS: Overall, the effect of race on bone outcomes did not differ by sex, and the effect of sex on bone outcomes did not differ by race. After adjusting for covariates, Black participants and men of both races had greater trabecular plate volume fraction, plate thickness, plate number density, plate surface area, and greater axial alignment of trabeculae, leading to higher trabecular bone stiffness compared to White participants and women, respectively (p < 0.05 for all). CONCLUSION: These findings demonstrate that more favorable bone microarchitecture in Black individuals compared to White individuals and in men compared to women is not unique to the cortical bone compartment. Enhanced plate-like morphology and greater trabecular axial alignment, established in young adulthood, may contribute to the improved bone strength and lower fracture risk in Black versus White individuals and in men compared to women.

[Review of survey method for human time-activity pattern and its application in the exposure assessment of air pollutants].

Time activity pattern refers to the time and behavior of people at different locations. The knowledge of time-activity pattern is essential for air pollution exposure assessment when direct personal exposure monitoring can't not be conducted, because air pollutant concentrations may vary significantly by location and activity. This review is focused on the survey method for human time-activity pattern and its application in the exposure assessment of air pollutants. After comparing the diary-reported trips and Global Positioning System (GPS) recording method, we believed that diary-reported trips were more reliable in describing comprehensive and detail records of the behavior and environmental circumstances while GPS-recorded trend to maintain sound information of time, location and transportations. Meanwhile, according to different subjects, the air pollution exposure model could be divided for population and individuals. There were great difference between two types of model in many areas, including the required information about time, activity and microenvironment.

Assessment of bullet effectiveness based on a human vulnerability model.

INTRODUCTION: Penetrating wounds from explosively propelled fragments and bullets are the most common causes of combat injury. There is a requirement to assess the potential effectiveness of bullets penetrating human tissues in order to optimise preventive measures and wound trauma management. METHODS: An advanced voxel model based on the Chinese Visible Human data was built. A digital human vulnerability model was established in combination with wound reconstruction and vulnerability assessment rules, in which wound penetration profiles were obtained by recreating the penetration of projectiles into ballistic gelatin. An effectiveness evaluation method of bullet penetration using the Abbreviated Injury Scale (AIS) was developed and solved using the Monte Carlo sampling method. RESULTS: The effectiveness of rifle bullets was demonstrated to increase with increasing velocity in the range of 300-700 m/s. When imparting the same energy, the effectiveness of the 5.56 mm bullet was higher than the 7.62 mm bullet in this model. CONCLUSIONS: The superimposition of simulant penetration profiles produced from ballistic gelatin simulant has been used to predict wound tracts in damaged tissues. The authors recognise that determining clinical effectiveness based on the AIS scores alone without verification of outcome by review of clinical hospital records means that this technique should be seen more as a manner of comparing the effectiveness of bullets than an injury prediction model.

Ideal cardiovascular health status and its association with socioeconomic factors in Chinese adults in Shandong, China.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the world. In 2010, a goal released by the American Heart Association (AHA) Committee focused on the primary reduction in cardiovascular risk. METHODS: Data collected from 7683 men and 7667 women aged 18-69 years were analyzed. The distribution of ideal cardiovascular health metrics based on 7 cardiovascular disease risk factors or health behaviors in according to the definition of AHA was evaluated among the subjects. The association of the socioeconomic factors on the prevalence of meeting 5 or more ideal cardiovascular health metrics was estimated by logistic regression analysis, and a chi-square test for categorical variables and the general linear model (GLM) procedure for continuous variables were used to compare differences in prevalence and in means among genders. RESULTS: Seven of 15350 participants (0.05 %) met all 7 cardiovascular health metrics. The women had a higher proportion of meeting 5 or more ideal health metrics compared with men (32.67 VS.14.27 %). The subjects with a higher education and income level had a higher proportion of meeting 5 or more ideal health metrics than the subjects with a lower education and income level. A comparison between subjects with meeting 5 or more ideal cardiovascular health metrics with subjects meeting 4 or fewer ideal cardiovascular health metrics reveals that adjusted odds ratio [OR, 95 % confidence intervals (95 % CI)] was 1.42 (0.95, 2.21) in men and 2.59 (1.74, 3.87) in women for higher education and income, respectively. CONCLUSIONS: The prevalence of meeting all 7 cardiovascular health metrics was low in the adult population. Women, young subjects, and those with higher levels of education or income tend to have a greater number of the ideal cardiovascular health metrics. Higher socioeconomic status was associated with an increasing prevalence of meeting 5 or more cardiovascular health metrics in women but not in men. It's urgent to develop comprehensive population-based interventions to improve the cardiovascular risk factors in Shandong Province in China.

The affordability for patients of a new universal MDR-TB coverage model in China.

BACKGROUND: China has piloted a new model of universal coverage for multidrug-resistant tuberculosis (MDR-TB), designed to rationalize hospital use of drugs and tests and move away from fee-for-service payment towards a standard package with financial protection against catastrophic health costs. OBJECTIVE: To evaluate the affordability to patients of this new model. DESIGN: This was an observational study of 243 MDR-TB cases eligible for enrolment on treatment under the project. We assessed the affordability of the project from the perspective of households, with a focus on catastrophic costs. RESULTS: Of the 243 eligible cases, 172 (71%) were enrolled on treatment; of the 71 cases not enrolled, 26 (37%) cited economic reasons. The 73 surveyed cases paid an average of RMB 5977 (US$920) out-of-pocket in search costs incurred outside the pilot model. Within the pilot, they paid another RMB 2094 (US$322) in medical fees and RMB 5230 (US$805) in direct non-medical costs. Despite 90% reimbursement of medical fees, 78% of households experienced catastrophic costs, including indirect costs. CONCLUSION: The objectives of the pilot model are aligned with health reform in China and universal health coverage globally. Enrollment would almost certainly be higher with 100% reimbursement of medical fees, but patient enablers will be required to truly eliminate catastrophic costs.

Development of virtual patient models for permanent implant brachytherapy Monte Carlo dose calculations: interdependence of CT image artifact mitigation and tissue assignment.

This work investigates and compares CT image metallic artifact reduction (MAR) methods and tissue assignment schemes (TAS) for the development of virtual patient models for permanent implant brachytherapy Monte Carlo (MC) dose calculations. Four MAR techniques are investigated to mitigate seed artifacts from post-implant CT images of a homogeneous phantom and eight prostate patients: a raw sinogram approach using the original CT scanner data and three methods (simple threshold replacement (STR), 3D median filter, and virtual sinogram) requiring only the reconstructed CT image. Virtual patient models are developed using six TAS ranging from the AAPM-ESTRO-ABG TG-186 basic approach of assigning uniform density tissues (resulting in a model not dependent on MAR) to more complex models assigning prostate, calcification, and mixtures of prostate and calcification using CT-derived densities. The EGSnrc user-code BrachyDose is employed to calculate dose distributions. All four MAR methods eliminate bright seed spot artifacts, and the image-based methods provide comparable mitigation of artifacts compared with the raw sinogram approach. However, each MAR technique has limitations: STR is unable to mitigate low CT number artifacts, the median filter blurs the image which challenges the preservation of tissue heterogeneities, and both sinogram approaches introduce new streaks. Large local dose differences are generally due to differences in voxel tissue-type rather than mass density. The largest differences in target dose metrics (D90, V100, V150), over 50% lower compared to the other models, are when uncorrected CT images are used with TAS that consider calcifications. Metrics found using models which include calcifications are generally a few percent lower than prostate-only models. Generally, metrics from any MAR method and any TAS which considers calcifications agree within 6%. Overall, the studied MAR methods and TAS show promise for further retrospective MC dose calculation studies for various permanent implant brachytherapy treatments.

Energy expenditure and fitness response following once weekly hill climbing at low altitude.

This work sought to determine the fitness responses and energy expenditure (EE) following once-weekly hill climbing for 16 weeks on different slopes. A cohort of 98 healthy, sedentary subjects (49 female, 49 male) completed the program at their preferred climbing pace. Body composition, resting metabolic rate (RMR) and VO2max were measured. EE was measured on 4 slopes (11.6°, 19.9°, 14.9°, and 28.6°) at the subjects' preferred speed. In males, weight, body mass index, fat mass significantly decreased (P<0.05), and RMR showed an increasing trend, but the difference was not significant (P=0.051). In females, the muscle mass increased significantly, and fat (%) and fat mass significantly decreased (P<0.05). Absolute and relative of VO2max, ventilation (VE) improved significantly in both sexes (P<0.01). Energy expenditure was similar on different slopes, but shows gender-specific values of approximately 50.4 and 33.6 kJ/min for males and females, respectively. The regression equation of EE (kJ/min)=[1.724×(female=1, and male=2)+(-0.072×age)+0.106×weight+0.024×HR+0.136×slope+1.487×velocity]×4.2. In conclusion, hill climbing at a subjects' preferred velocity is a vigorous-intensity physical activity for energy cost and, performed once weekly, enhances cardiorespiratory fitness and reduces fat mass, therefore making it a viable exercise for most people.

Phase transitions in a coevolving snowdrift game with costly rewiring.

We propose and study a dissatisfied adaptive snowdrift game with a payoff parameter r that incorporates a cost for rewiring a connection. An agent, facing adverse local environment, may switch action without a cost or rewire an existing link with a cost a so as to attain a better competing environment. Detailed numerical simulations reveal nontrivial and nonmonotonic dependence of the frequency of cooperation and the densities of different types of links on a and r. A theory that treats the cooperative and noncooperative agents separately and accounts for spatial correlation up to neighboring agents is formulated. The theory gives results that are in good agreement with simulations. The frequency of cooperation f_{C} is enhanced (suppressed) at high rewiring cost relative to that at low rewiring cost when r is small (large). For a given value of r, there exists a critical value of the rewiring cost below which the system evolves into a phase of frozen dynamics with isolated noncooperative agents segregated from a cluster of cooperative agents, and above which the system evolves into a connected population of mixed actions with continual dynamics. The phase boundary on the a-r phase space that separates the two phases with distinct structural, population and dynamical properties is mapped out. The phase diagram reveals that, as a general feature, for small r (small a), the disconnected and segregated phase can survive over a wider range of a(r).

Non-invasive assessment of liver fibrosis using real-time tissue elastography in patients with chronic hepatitis B.

AIM: To evaluate the utility of the elastic ratio calculated using real-time tissue elastography for assessing liver fibrosis in patients with chronic hepatitis B (CHB). MATERIALS AND METHODS: Ninety-six patients with CHB were enrolled between September 2012 and August 2013. The elastic ratio of the liver for the intrahepatic venous small vessel was calculated to measure liver stiffness. Diagnostic performance of the elastic ratio and aminotransferase-to-platelet ratio index (APRI) were compared with histological fibrosis stage at liver biopsy. In addition, 45 healthy adult volunteers were participated in intra- and interobserver reliability studies. RESULTS: There was no significant influence of hepatitis B e antigen (HBeAg) status or hepatitis B virus DNA levels on the elastic ratio measurements in CHB patients. The elastic ratio was significantly correlated with histological fibrosis stage (r = 0.873, p < 0.001). Cut-off values were 2.62 for stage 2 and over (S ≥ 2), 3.20 for state 3 and over, and 3.86 for stage 4, respectively. The areas under the receiver operating characteristic (ROC) curves for elastic ratio and APRI diagnosis of significant fibrosis (S ≥ 2) was 0.91 (95% CI: 0.84-0.98) and 0.71 (95% CI: 0.57-0.86), and 0.94 (95% CI: 0.89-0.99) and 0.81 (95% CI: 0.71-0.91) for cirrhosis (S = 4), respectively. The elastic ratio measurements had good reproducibility: 0.838 for intra-observer reliability and 0.805 for inter-observer reliability, respectively (p < 0.001). CONCLUSION: Elastic ratio determined using real-time tissue elastography was an accurate and reproducible method for evaluating liver fibrosis in patients with CHB.

Establishment of tacrolimus-induced diabetes in rat model and assessment of clinical treatments for post-transplant diabetes mellitus in liver transplant recipients.

BACKGROUND: To establish a tacrolimus-induced diabetes rat model and assess efficacy and safety of insulin glargine combined with repaglinide in Chinese patients with diabetes after liver transplantation. METHODS: Animal experiments and clinical trial were conducted. Animal experiments: Male SD rats were randomly divided into tacrolimus (4 mg/kg daily) and control group (saline). Rats were sacrificed after five months of treatment and blood was collected through heart puncture. Patients who underwent liver transplantation were selected and followed up regularly. If HbA1c was < 9%, repaglinide was administered; if HbA1c was > or = 9%, glargine plus repaglinide was administered. RESULTS: For rat model studies, in the tacrolimus group, fasting blood glucose (FBG) levels were increased after three months (p < 0.01). After five months, the insulin secretion index and the sensitivity index in the tacrolimus group was significantly lower than in the control group (p < 0.01). For studies of post-transplant diabetes mellitus (PTDM), eighty-six liver transplant recipients were enrolled. 51 were given repaglinide and 35 were given repaglinide combined with glargine. After treatment for 1, 6, and 12 months, FBG, post-prandial blood glucose (PPBG), and HbA1c levels decreased (p < 0.05) in both groups, and no statistically significant changes were observed in the liver and kidney function indicators (p > 0.05). No severe hypoglycemia episodes were reported. CONCLUSIONS: Tacrolimus caused islet cell necrosis, reduced insulin secretion, increased insulin resistance, and increased blood glucose in the model. The blood glucose levels increased in a time-dependent manner. Combination of glargine and repaglinide was effective and safe for Chinese patients with post liver transplant diabetes mellitus.

The remote assessment of melanocytic skin lesions: a viable alternative to face-to-face consultation.

BACKGROUND: The incidence of melanoma continues to rise in the Western world, prompting health care professionals to search for novel tools that may increase rates of early detection. Here we focus on one such tool: remote specialist diagnosis of melanocytic lesions utilising mobile-phone camera patient-generated clinical images. OBJECTIVE: We aim to test the hypothesis that patient-generated clinical images utilising mobile phones are of acceptable quality, and that digital image diagnostic outcomes are comparable with face-to-face (FTF) diagnostic outcomes. METHODS: Study participants were asked to photograph, using their mobile-phone camera any number of their own melanocytic naevi, and then upload these clinical images to a central server. Diagnostic accuracy of the management decision based on assessing these digital images was tested by comparing results from digital image assessment with results from FTF assessments. RESULTS: We provide evidence that suggests potential patients are capable of uploading good quality clinical images of melanocytic lesions for diagnostic purposes, and we show that good concordance rates can be achieved with respect to digital image and FTF diagnostic outcomes. With respect to the latter, exact agreement was found in 116 of 167 assessable lesions (69%). CONCLUSIONS: This work suggests that specialist remote diagnosis of patient-generated clinical images of melanocytic lesions utilising mobile-phone cameras may be a viable alternative to traditional FTF assessments.

Rapid detection of H5 avian influenza virus by TaqMan-MGB real-time RT-PCR.

AIMS: Real-time reverse transcription-polymerase chain reaction (RT-PCR) assay based on a TaqMan-minor groove binder (MGB) probe was developed for the rapid detection of avian influenza virus subtype H5. METHODS AND RESULTS: Conserved regions in the haemagglutinin genes of avian influenza viruses subtype H5 served as targets for the primers and TaqMan-MGB probe design. Concentrations of primers and probe were optimized to improve the sensitivity and specificity of the reactions. A plasmid containing the haemagglutinin gene was constructed and in vitro transcribed for a quantitative assay of copy numbers of the target gene. The results revealed that the optimal concentration of primers and probe was 640 and 480 nmol l(-1), respectively. The threshold of 100 copies of target molecules could be detected. The linear range for detection was determined as 10(2) to 10(8) molecules in reaction. CONCLUSIONS: It took less than 3 h to complete the detection from viral RNA extraction, with good sensitivity and repeatability. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time RT-PCR assay with MGB probe was an effective means for quick and quantitative laboratory detection and monitoring of H5 avian influenza viruses.

Simultaneous improvement for four quality traits of Zhenshan 97, an elite parent of hybrid rice, by molecular marker-assisted selection.

"Zhenshan 97" is the female parent of a number of widely used hybrids for rice production in China. However, this line is of poor quality because of a high amylose content (AC), a hard gel consistency (GC) and a low gelatinization temperature (GT), together with a chalky endosperm. It had been determined that the three traits for cooking and eating quality, AC, GC and GT, are controlled by the Waxy locus and/or the tightly linked genomic region. In this study we improved the eating and cooking quality of Zhenshan 97 by introgressing the Waxy gene region from Minghui 63 (wx-MH), a restorer line, that has medium AC, soft GC and high GT. The wx-MH fragment was transferred to Zhenshan 97B by three backcrosses and one selfing, then from Zhenshan 97B to Zhenshan 97A by a cross and a backcross. Molecular marker-assisted selection was applied in the series to select for individuals carrying wx-MH, to identify recombination between the Waxy and flanking markers, and also to recover the genetic background of the recurrent parent. According to the marker genotypes, the improved versions of Zhenshan 97B and Zhenshan 97A, or Zhenshan 97B(wx-MH) and Zhenshan 97A(wx-MH), were the same as the originals except for the Waxy region of less than 6.1 cM in length. The selected lines and their hybrids with Minghui 63, or Shanyou 63(wx-MH), showed a reduced AC and an increased GC and GT, coupled with a reduced grain opacity. Field examinations of agronomic performance revealed that Zhenshan 97B(wx-MH) and Shanyou 63(wx-MH) were essentially the same as the originals except for a significant decrease in grain weight. The simultaneous improvement of AC, GA, GT and opacity, indicated that the Waxy region had major effects on the four quality traits. The improved versions of Zhenshan 97 A and B should be immediately useful in hybrid rice production.

Determination of peripheral blood stem cells by the Sysmex SE-9500.

The Sysmex SE-9500 automated haematology analyser provides an estimate of immature cells, referred to as 'haematopoietic progenitor cells' (HPC). The aim of this study was to evaluate the reliability and usefulness of the SE-9500 HPC parameter as compared with the CD34 + cell count and to determine whether the HPC count was of value in predicting the optimal harvesting time for peripheral blood stem cells (PBSC). Studies were performed on 112 samples from 21 patients with haematological malignancies and 13 healthy donors undergoing progenitor cell mobilisation. Coefficients of variation for the HPC count were 30%, 23.8%, 12.4% and 8.3% respectively for samples with low (4 x 106/l), medium (13 x 106/l), high (250 x 106/l) and very high (2413 x 106/l) counts. There was good linearity for HPC measurement in both peripheral blood (PB) and purified CD34 + cell suspensions (r > 0.995), and no detectable carryover was observed. There was an acceptable correlation between HPC and CD34 + cell counts for PB samples (r=0.669) and for CD34 + cell suspensions (r=0.859). Analysis of purified CD34 + cells using the SE-9500 HPC mode revealed that they appear both in the blast cell area and the immature granulocyte area of the analyser cell display. Quantitation of CD34 + cells and HPC during PBSC mobilisation showed good agreement between these parameters with regard to the optimal time for PBSC harvesting. These findings suggest that HPC counting with the Sysmex SE-9500 may be clinically useful for optimising the timing of PBSC collection.

Assessment of electrokinetic removal of heavy metals from soils by sequential extraction analysis.

Electrokinetic remediation of metal-contaminated soils is strongly affected by soil-type and chemical species of contaminants. This paper investigates the speciation and extent of migration of heavy metals in soils during electrokinetic remediation. Laboratory electrokinetic experiments were conducted using two diverse soils, kaolin and glacial till, contaminated with chromium as either Cr(III) or Cr(VI). Initial total chromium concentrations were maintained at 1000mg/kg. In addition, Ni(II) and Cd(II) were used in concentrations of 500 and 250mg/kg, respectively. The contaminated soils were subjected to a voltage gradient of 1 VDC/cm for over 200h. The extent of migration of contaminants after the electric potential application was determined. Sequential extractions were performed on the contaminated soils before and after electrokinetic treatment to provide an understanding of the distribution of the contaminants in the soils. The initial speciation of contaminants was found to depend on the soil composition as well as the type and amounts of different contaminants present. When the initial form of chromium was Cr(III), exchangeable and soluble fractions of Cr, Ni, and Cd ranged from 10 to 65% in kaolin; however, these fractions ranged from 0 to 4% in glacial till. When the initial form of chromium was Cr(VI), the exchangeable and soluble fractions of Cr, Ni and Cd ranged from 66 to 80% in kaolin. In glacial till, however, the exchangeable and soluble fraction for Cr was 38% and Ni and Cd fractions were 2 and 10%, respectively. The remainder of the contaminants existed as the complex and precipitate fractions. During electrokinetic remediation, Cr(VI) migrated towards the anode, whereas Cr(III), Ni(II) and Cd(II) migrated towards the cathode. The speciation of contaminants after electrokinetic treatment showed that significant change in exchangeable and soluble fractions occurred. In kaolin, exchangeable and soluble Cr(III), Ni(II), and Cd(II) decreased near the anode and increased near the cathode, whereas exchangeable and soluble Cr(VI) decreased near the cathode and increased near the anode. In glacial till, exchangeable and soluble Cr(III), Ni(II), and Cd(II) were low even before electrokinetic treatment and no significant changes were observed after the electrokinetic treatment. However, significant exchangeable and soluble Cr(VI) that was present in glacial till prior to electrokinetic treatment decreased to non-detectable levels near the cathode and increased significantly near the anode. In both kaolin and glacial till, low migration rates occurred as a result of contaminants existing as immobile complexes and precipitates. The overall contaminant removal efficiency was very low (less than 20%) in all tests.

Current methods in medical image segmentation.

Image segmentation plays a crucial role in many medical-imaging applications, by automating or facilitating the delineation of anatomical structures and other regions of interest. We present a critical appraisal of the current status of semi-automated and automated methods for the segmentation of anatomical medical images. Terminology and important issues in image segmentation are first presented. Current segmentation approaches are then reviewed with an emphasis on the advantages and disadvantages of these methods for medical imaging applications. We conclude with a discussion on the future of image segmentation methods in biomedical research.