The standardized training and assessment system for magnetically controlled capsule gastroscopy (with video).

BACKGROUND AND AIM: To explore the feasibility of a standardized training and assessment system for magnetically controlled capsule gastroscopy (MCCG). METHODS: The results of 90 trainees who underwent the standardized training and assessment system of the MCCG at the First Affiliated Hospital of Xi'an Jiaotong University from May 2020 to November 2023 was retrospectively analyzed. The trainees were divided into three groups according to their medical backgrounds: doctor, nurse, and non-medical groups. The training and assessment system adopted the '7 + 2' mode, seven days of training plus two days of theoretical and operational assessment. The passing rates of theoretical, operational, and total assessment were the primary outcomes. Satisfaction and mastery of the MCCG was checked. RESULTS: Ninety trainees were assessed; theoretical assessment's passing rates in the three groups were 100%. The operational and total assessment passing rates were 100% (25/25), 97.92% (47/48), and 94.12% (16/17), for the doctor, nurse, and non-doctor groups respectively, with no significant difference (χ2 = 1.741, p = 0.419). No bleeding or perforation occurred during the procedure. Approximately, 96.00% (24/25), 95.83% (46/48), and 94.12% (16/17) of the doctor, nurse and non-medical groups anonymously expressed great satisfaction, respectively, without statistically significant difference (χ2 = 0.565, p = 1.000). The average follow-up time was 4-36 months, and 87 trainees (96.67%) had mastered the operation of the MCCG in daily work. CONCLUSIONS: Standardized training and assessment of magnetically controlled capsule endoscopists is effective and feasible. Additionally, a strict assessment system and long-term communication and learning can improve teaching effects.

[Characterization of Metal Elements in Atmospheric PM2.5 and Health Risk Assessment in Heze in Winter from 2017 to 2018].

Atmospheric PM2.5 samples were collected in Heze, Shandong Province, from a total of three sampling sites at Heze College, Huarun Pharmacy, and a wastewater treatment plant between October 15, 2017 and January 31, 2018, to determine the concentrations of 21 metal elements in PM2.5 using inductively coupled plasma mass spectrometry (ICP-MS). The degree of elemental enrichment was also discussed, the health risks and potential heavy metal ecological risks were assessed. The results showed that ρ (PM2.5) ranged from 26.7 to 284.1 µg·m-3 at the three sampling sites during the sampling period, and the concentration values did not differ significantly, all of which were at high pollution levels. The highest concentrations of K were found in the three sampling sites, accounting for 31.03%, 39.47%, and 38.43% of the total, respectively, mainly due to the high contribution of biomass burning in autumn and winter in Heze, a large agricultural city. The highest concentrations of Zn, 89.70, 84.21, and 67.68 ng·m-3, were found in the trace elements at the three sampling sites, respectively. The enrichment factor results showed that the enrichment factor values of Zn, Pb, Sn, Sb, Cd, and Se were higher than 100, among which the enrichment factors of Cd and Se were higher than 2 000 and 4 000, respectively, which were significantly influenced by anthropogenic activities and might have been related to industrial production, metal smelting, road sources, and coal combustion emissions. The health risk results showed that there was some potential non-carcinogenic risk (HQ>0.1 for children and adults) for As and a combined potential non-carcinogenic risk (HI>0.1) and some potential carcinogenic risk (CRT>1×10-6) for both children and adults at the three sampling sites. There was a more significant carcinogenic risk (CRT>1×10-4) for adults at the wastewater treatment plant, and the slightly higher carcinogenic risk for adults than that for children may have been related to the longer outdoor activity and higher PM2.5 exposure for adults. The elements with the highest potential ecological risk values were Cd, As, and Pb, with Cd exhibiting a very high potential ecological risk that should be taken seriously. All three sampling sites showed a very high combined potential ecological risk, with the intensity spatially expressed as Heze College>Huarun Pharmacy>wastewater treatment plant.

Adaptability of water resources development and utilization to social-economy system in Hunan province, China.

The interplay of water resources with social-economy spheres involves a reciprocal feedback mechanism. With the acceleration of the construction process of modernized water networks in Hunan Province, investigating the adaptation status of the "Water-Social-Economy " composite system (WSE) is crucial for promoting sustainability. This study clarifies the connotation of the adaptability of WSE, and the quantitative analyses were conducted through coupling coordinative degree, harmonious development capacity, and the evolution of development lag types among the 14 cities of Hunan Province from 2005 to 2020. The results show that: (1) The development index of the water resources subsystem (WRS) showed a "downward-fluctuation-upward" trend, while the development index of the social-economy subsystem (SES) showed signs of great improvement, the former didn't catch up with the latter. (2) The coupling coordination degree of WSE developed well, and reached the coordinative development stage by 2020, but the unbalanced spatial pattern between north to south and east to west still exists and is further intensified. (3) The development ability of WSE improved while the harmony ability reduced, and the development rate of WRS and SES hasn't achieved dynamic synchronization. Finally, the policies and suggestions to improve the adaptability are put forward, which is of instructive significance for the sustainable development of water suitability.

Assessment of ForenSeq mtDNA Whole Genome Kit for forensic application.

Mitochondrial DNA (mtDNA) is an indispensable genetic marker in forensic genetics. The emergence and development of massively parallel sequencing (MPS) makes it possible to obtain complete mitochondrial genome sequences more quickly and accurately. The study evaluated the advantages and limitations of the ForenSeq mtDNA Whole Genome Kit in the practical application of forensic genetics by detecting human genomic DNA standards and thirty-three case samples. We used control DNA with different amount to determine sensitivity of the assay. Even when the input DNA is as low as 2.5 pg, most of the mitochondrial genome sequences could still be covered. For the detection of buccal swabs and aged case samples (bloodstains, bones, teeth), most samples could achieve complete coverage of mitochondrial genome. However, when ancient samples and hair samples without hair follicles were sequenced by the kit, it failed to obtain sequence information. In general, the ForenSeq mtDNA Whole Genome Kit has certain applicability to forensic low template and degradation samples, and these results provide the data basis for subsequent forensic applications of the assay. The overall detection process and subsequent analysis are easy to standardize, and it has certain application potential in forensic cases.

Prognostic Significance of Preprocedural N-Terminal Pro-B-Type Natriuretic Peptide Assessment in Diabetic Patients With Multivessel Coronary Disease Undergoing Revascularization.

Background and Aims: The N-terminal pro-B-type natriuretic peptide (NT-proBNP) may predict adverse cardiovascular outcomes in patients with diabetes. However, its prognostic value in patients with multivessel disease (MVD) undergoing coronary revascularization remains unclear. This study aimed to evaluate the prognostic significance of preprocedural NT-proBNP levels in diabetic patients with MVD undergoing coronary revascularization. Methods: A total of 886 consecutive diabetic patients with MVD who underwent coronary revascularization were enrolled in this study. Patients were divided into quartiles according to their pre-procedural NT-proBNP levels. Kaplan-Meier curves and Cox regression analyses were performed to evaluate the risk of cardiovascular events, including all-cause death, cardiovascular death, myocardial infarction (MI), stroke, and major adverse cardiovascular events (MACE), according to the NT-proBNP quartiles. Results: During a median follow-up period of 4.2 years, 111 patients died (with 82 being caused by cardiovascular disease), 133 had MI, 55 suffered from stroke, and 250 experienced MACE. Kaplan-Meier curves demonstrated that NT-proBNP levels were significantly associated with higher incidences of all-cause death, cardiovascular death, MI, and MACE (log-rank test, P < 0.001, respectively). Multivariate Cox regression analysis revealed that NT-proBNP level was an independent predictor of adverse outcomes, including all-cause death (HR, 1.968; 95% CI, 1.377-2.812; P < 0.001), cardiovascular death (HR, 1.940; 95% CI, 1.278-2.945; P = 0.002), MI (HR, 1.722; 95% CI, 1.247-2.380; P = 0.001), and MACE (HR, 1.356; 95% CI, 1.066-1.725; P = 0.013). The role of NT-proBNP in predicting adverse outcomes was similar in patients with stable angina pectoris and acute coronary syndrome. Moreover, preprocedural NT-proBNP alone discriminated against the SYNTAX II score for predicting all-cause death [area under the curve (AUC), 0.662 vs. 0.626, P = 0.269], cardiovascular death (AUC, 0.680 vs. 0.622, P = 0.130), MI (AUC, 0.641 vs. 0.579, P = 0.050), and MACE (AUC, 0.593 vs. 0.559, P = 0.171). The addition of NT-proBNP to the SYNTAX II score showed a significant net reclassification improvement, integrated discrimination improvement, and improved C-statistic (all P < 0.05). Conclusion: NT-proBNP levels were an independent prognostic marker for adverse outcomes in diabetic patients with MVD undergoing coronary revascularization, suggesting that preprocedural NT-proBNP measurement might help in the risk stratification of high-risk patients.

Development of Chinese mesh-type pediatric reference phantom series and application in dose assessment of Chinese undergoing computed tomography scanning.

Pediatric patients are in a growing stage with more dividing cells than adults. Therefore, they are more sensitive to the radiation dose when undergoing computed tomography (CT) scanning. It is necessary and essential to assess the organ absorbed dose and effective dose to children. Monte Carlo simulation with computational phantoms is one of the most used methods for dose calculation in medical imaging and radiotherapy. Because of the vast change of the pediatric body with age increasing, many research groups developed series pediatric phantoms for various ages. However, most of the existing pediatric reference phantoms were developed based on Caucasian populations, which is not conformable to Chinese pediatric patients. The use of different phantoms can contribute to a difference in the dose calculation. To assess the CT dose of Chinese pediatric patients more accurately, we developed the Chinese pediatric reference phantoms series, including the 3-month (CRC3m), 1-year-old (CRC01), 5-year-old (CRC05), 10-year-old (CRC10), 15-year-old male (CRCM15), and a 15-year-old female (CRCF15) phantoms. Furthermore, we applied them to dose assessment of patients undergoing CT scanning. The GE LightSpeed 16 CT scanner was simulated and the paper presents the detailed process of phantoms development and the establishment of the CT dose database (with x-ray tube voltages of 120, 100 and 80 kVp, with collimators of 20, 10, and 5 mm width, with filters for head and body), compares for the 1-year-old results with other results based on different phantoms and analyzes the CT dose calculation results. It was found that the difference in phantoms' characteristics, organ masses and positions had a significant impact on the CT dose calculation outcomes. For the 1-year-old phantom, the dose results of organs fully covered by the x-ray beam were within 10% difference from the results of other studies. For organs partially covered and not covered by the scan range, the maximum differences came up to 84% (stomach dose, chest examinations) and 463% (gonads dose, chest examinations) respectively. The findings are helpful for the dose optimization of Chinese pediatric patients undergoing CT scanning. The developed phantoms could be applied in dose estimation of other medical modalities.

A Newly Designed Seed-Loading Device for Verifying the Safety of 125I Implants to the Canine Carotid Artery.

A seed-loading device was designed and modeled using the Monte Carlo method to verify the biological effect of iodine-125 (125I) particles on blood vessels through animal experiments. The dose distribution characteristics of irradiated vessels were established by adjusting the design variables and geometry. The deviation between the actual value and the theoretical value was verified in vitro by the thermoluminescence dosimetry (TLD) method. After verification, the device was used to examine the biological effect of 125I irradiation of canine carotid arteries in two dogs (and one control dog) for 180 days. The hollow cylinder seed-loading device was constructed with an inner diameter of 0.5 cm and a length of 3.3 cm. When six seeds were loaded into a single layer, the source strength ratio of the intermediate layer to the edge layer was 0.7:1. When six layers of seeds were arranged at 0.45-cm intervals, the deviations between the maximum, minimum and mean energy fluence within 2.25 cm of the vessel wall were 2.19% and -4.12%, respectively, and -9% and 4%, respectively, when verified in vitro using TLD. The carotid arteries showed good tolerance to 0.56 kGy (range of 0.51-0.58 kGy) after 180 days of irradiation. In conclusion, this 125I seed-loading device overcomes the random distribution of seeds and lays an accurate radiophysical foundation for subsequent biological experiments. The preliminary results showed that the carotid artery has good tolerance to 0.56 kGy irradiation.

Screening value for gastrointestinal lesions of magnetic-controlled capsule endoscopy in asymptomatic individuals.

BACKGROUND AND AIM: Most patients with gastric tumors and precancerous lesions are asymptomatic, which often results in delayed diagnosis and treatment. Compared with conventional gastroscopy and capsule endoscopy, magnetic-controlled capsule endoscopy is a non-invasive, effective, and cost-efficient diagnostic modality for gastric examination. We retrospectively investigated magnetic-controlled capsule endoscopy as a screening tool for gastrointestinal lesions (particularly gastric tumors and precancerous lesions) in asymptomatic individuals. METHODS: In this retrospective study, 1757 patients who voluntarily underwent magnetic-controlled capsule endoscopy between January and December 2019 at nine medical centers across Shaanxi province based on strict inclusion and exclusion criteria were enrolled. The primary outcomes were gastric tumor and precancerous lesion detection rates and procedural safety. RESULTS: The upper and lower gastrointestinal lesion detection rates were 98.35% (1728/1757) and 21.61% (78/361), respectively; 2.28% of patients were diagnosed with gastric tumors including gastric cancer (4/1757) and submucosal tumors (36/1757). Three types of precancerous lesions were found in 591 patients (33.64%), including chronic atrophic gastritis (23.16%), gastric polyp (10.98%), and gastric ulcer (2.96%). For patients aged over 40 years, the detection rate of precancerous lesions was higher (14.36% vs 42.58%, P < 0.001). No patient was diagnosed with small intestinal cancer. No adverse events occurred. CONCLUSIONS: Magnetic-controlled capsule endoscopy could be used as a promising novel screening modality for diagnosis of gastrointestinal lesions in asymptomatic individuals, specifically gastric tumors and precancerous lesions, with the advantages of safety, non-invasiveness, effectiveness, and cost-efficiency.

Crizotinib versus chemotherapy: a real-world cost-effectiveness study in China.

Aim: To assess the cost-effectiveness of crizotinib verses platinum-based doublet chemotherapy as the first-line treatment for anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) in the real-world setting. Methods: Data from 163 advanced ALK positive NSCLC patients were collected from West China Hospital, Sichuan University (Chengdu, China). They were categorized into two groups as treated with crizotinib (n = 83) or chemotherapy (n = 80) as a first-line therapy. The progression-free survival (PFS) as the primary clinical outcome, and the direct medical costs were collected from hospital information systems. Incremental cost-effectiveness ratio (ICER) was calculated with costs, quality-adjusted life-years, as well as the costs discounted at 3% annually. Additionally, two different kinds of medical insurance (MI) for pharma-economic assessment were considered. Results: Crizotinib improved PFS versus chemotherapy in ALK positive patients (median PFS 19.67 m vs 5.47 m; p < 0.001). Moreover, crizotinib obtained an ICER of US$36,285.39 before the end of 2016, when crizotinib, pemetrexed and anti-angiogenesis drugs were not MI covered. This is more than the willingness to pay threshold (three-times of gross domestic product per capita in mainland China or Sichuan Province). However, ICER was US$7321.16, which is less than willingness to pay, when crizotinib and all chemotherapy drugs were covered by MI from the end of 2016. Sensitivity analysis demonstrated a 99.7% probability for crizotinib to be more cost-effective than chemotherapy, when crizotinib and all anticancer drugs were MI covered. One-way sensitivity analysis for the reimbursement ratio of crizotinib indicated that cost-effective tendency for crizotinib increased as reimbursement ratio increased. Conclusion: Crizotinib could be an effective, and cost-effective first-line treatment for ALK positive advanced NSCLC with the MI coverage currently available in Chengdu, Sichuan Province, China.

An environmental flow assessment of a river's blocking effect on a lake in a river-lake system: application in the Yangtze-Poyang system.

Hydrologic regimes are essential to riverine, lacustrine, and wetland ecosystems, and every component of a hydrologic regime has a specific ecological environmental function. In an outflow lake-river system, water levels are reduced by a reservoir constructed at the river, which interferes with the river-lake interrelationships by impairing the river's blocking effect. This increases the lake-river hydraulic gradient and accelerates the lake's drainage to the river, resulting in shrinkage of the lake and damaging environmental issues. To respond to these issues, we propose an environmental flow assessment that considers the river's blocking effect on the lake. This novel methodology consists of four steps: data preparation, assessment of the lake's environmental water level, assessment of the river's environmental water level, and environmental flow assessment. We estimated the river's environmental water level through a hydraulic correlation between the lake and the river, and found that the river's blocking effect could be sustained. The Yangtze-Poyang system was selected as a case study to illustrate the methodology's procedures and applicability. The impoundment of the Three Gorges Reservoir, during the fall retreating season, decreased the Yangtze's water level and weakened the Yangtze's blocking effect on Poyang Lake. Poyang Lake's environmental water level, which ranges from 11.71 to 15.81 m in the month of October, was used to estimate the Yangtze's environmental water level as falling in a range of 11.95 to 16.17 m, which corresponds to an environmental flow range of 16,822 to 32,371 m3/s. This study offers a solution for reservoir-induced accelerated lake drainage, which may be helpful in mitigating the negative impacts of reservoirs and sustaining natural rive-lake interactions.

Assessment of programmed cell death ligand-1 expression with multiple immunohistochemistry antibody clones in non-small cell lung cancer.

BACKGROUND: Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with PD-L1 as a potential predictive biomarker. However, a specific antibody for PD-L1 expression is an immediate requirement. Meanwhile, the clinicopathological identification of patients with positive PD-L1 remains unclear. METHODS: The present study adopted three anti-PD-L1 IHC antibodies, SP142, SP263, and UMAB228 to test PD-L1 expression in 84 non-small cell lung cancer (NSCLC) specimens. The concordance among antibodies was examined by analytical comparison, and the association between PD-L1 expression and clinicopathological factors was assessed. RESULTS: The samples from 41 (48.8%), 51 (60.7%), and 50 (59.5%) patients were detected as PD-L1 positive evaluated by antibody SP142, SP263, and UMAB228, respectively. The kappa coefficient was 0.53, 0.58, and 0.46 for SP263 vs. SP142, SP263 vs. UMAB228, and SP142 vs. UMAB228, respectively. On the other hand, the univariate analysis of consensus cases indicated that the PD-L1 expression was significantly correlated with tobacco use (χ2=4.25, P=0.04). CONCLUSIONS: The analytical comparison showed moderate concordance between SP142, SP263 and UMAB228, whereas SP263 exhibited higher overall positive rate. Moreover, PD-L1 positive rate was significantly higher in patients with smoking history, which might help in identifying patients who would benefit from PD-1/PD-L1 checkpoint inhibitors.

DOSE DISTRIBUTION IN A BREAST UNDERGOING MAMMOGRAPHY BASED ON A 3D DETAILED BREAST MODEL FOR CHINESE WOMEN.

Not only the mean glandular dose (MGD) but also the glandular dose distribution is important in describing the radiation exposure to breast in mammography. For a more precise knowledge of the absorbed dose distribution in the breast, experimental measurements with thermoluminescence dosemeter and Monte Carlo simulations with Geant4 were performed in this study. The experimental measurements with homogeneous physical breast phantoms were used to validate Monte Carlo simulations of homogeneous mathematical breast models undergoing mammography. Then a 3D detailed breast model with a compressed breast thickness of 4 cm and a glandular content of 50%, which has been constructed in previous work, was used to study the absorbed dose distribution inside the breast undergoing mammography. Furthermore, the effects of the glandular tissue distribution on MGD were studied by reversing the breast model in head-toe direction to get a breast model with a different distribution of glandular tissues.

Determination and Safety Assessment of Residual Spirotetramat and Its Metabolites in Amaranth (Amaranthus tricolor) and Soil by Liquid Chromatography Triple-Quadrupole Tandem Mass Spectrometry.

With the purpose of guaranteeing the safe use of spirotetramat and preventing its potential health threats to consumers, a QuEChERS extraction method coupled with LC triple-quadrupole tandem MS was applied in this study to determine residual spirotetramat metabolites in different tissues of amaranth (Amaranthus tricolor) and in soil. The results indicate that the spirotetramat degraded into different types of metabolites that were located in different tissues of amaranth and in soil. B-keto, B-glu, and B-enol were the three most representative degradation products in the leaf of amaranth, and B-glu and B-enol were the two major degradation products found in the stem of amaranth; however, only B-enol was detected in the root of amaranth. B-keto and B-mono were the two products detected in the soil in which the amaranth grew. The cytotoxicity results demonstrate that spirotetramat and its metabolite B-enol inhibited cellular growth, and the toxicity of spirotetramat and its metabolite B-enol exceeded than that of the metabolites B-keto, B-mono, and B-glu. This investigation is of great significance to the safe use of spirotetramat in agriculture.

Dosimetric characterization of GMS BT-125-1 125 I radioactive seed with Monte Carlo simulations and experimental measurement.

PURPOSE: To investigate the dosimetric characteristics of the new GMS BT-125-1 125 I radioactive seed, including dose rate constant, radial dose functions, and anisotropy functions. METHODS: Dosimetric parameters of GMS BT-125-1 125 I seed including dose rate constant, radial dose functions, and anisotropy functions were calculated using the Monte Carlo code of MCNP5, and measured with thermoluminescent dosimeters (TLDs). The results were compared with those of PharmaSeed BT-125-1, PharmaSeed BT-125-2 125 I, and model 6711 125 I seeds. RESULTS: The dose rate constant of GMS BT-125-1 125 I seed was 0.959 cGy·h-1·U-1, with the difference of 0.94%, 0.83%, and 0.73% compared with the PharmaSeed BT-125-1 125 I seed, PharmaSeed BT-125-2 125 I seed, and Model 6711 125 I seed, respectively. For radial dose function, the differences between the Monte Carlo and the experimental g(r) results were mostly within 10%. Monte Carlo results of g(r) for GMS BT-125-1 125 I seed were found in agreement (within 3.3%) with corresponding results for the PharmaSeed BT-125-2 125 I seed. The largest differences were 8.1% and 6.2% compared with PharmaSeed BT-125-1 125 I seed and model 6711 125 I seed, respectively. For anisotropy function, the difference between GMS BT-125-1 125 I seed and PharmaSeed BT-125-2 125 I seed was typically <10%. CONCLUSIONS: The measured dose rate constant, radial dose functions, and two-dimensional anisotropy functions for the GMS BT-125-1 125 I seed showed good agreement with the Monte Carlo results. The dose rate constant of the GMS BT-125-1 125 I seed is similar to that of the PharmaSeed BT-125-1 125 I seed, the PharmaSeed BT-125-2 125 I seed, and the model 6711 125 I seed. For radial dose functions and two-dimensional anisotropy functions, the GMS BT-125-1 125 I seed is similar to the PharmaSeed BT-125-2 125 I seed but different from the PharmaSeed BT-125-1 125 I seed and the model 6711 125 I seed.

Monte Carlo calculation of conversion coefficients for dose estimation in mammography based on a 3D detailed breast model.

PURPOSE: At present, the Chinese specification for testing of quality control in x-ray mammography is based on a simple breast model, and does not consider the glandular tissue distribution in the breast. In order to more precisely estimate the mean glandular dose (MGD) in mammography for Chinese women, a three-dimensional (3D) detailed breast model based on realistic structures in the breast and Chinese female breast parameters was built and applied in this study. METHODS: To characterize the Chinese female breast, Chinese female breast parameters including breast size, compressed breast thickness (CBT), and glandular content were investigated in this study. A mathematical model with the detailed breast structures was constructed based on the Chinese female breast parameters. The mathematical model was then converted to a voxel model with voxels. The voxel model was compressed in craniocaudal (CC) view to obtain a deformation model. The compressed breast model was combined with the Chinese reference adult female whole-body voxel phantom (CRAF) to study the effects of backscatter from the female body. Monte Carlo simulations of the glandular dose in mammography were performed with Geant 4. The glandular tissue dose conversion coefficients for breasts with different glandular contents (5%, 25%, 50%, 75%, and 100% glandularity) and CBTs (3 cm, 4 cm, 5 cm, and 6 cm) were calculated, respectively, at various x-ray tube voltages (25 kV, 28 kV, 30 kV, 32 kV, and 35 kV) for various target/filter combinations (Mo/Mo, Mo/Rh, Rh/Rh, and W/Rh). RESULTS: A series of glandular tissue dose conversion coefficients for dose estimation in mammography were calculated. The conversion coefficients calculated in this study were compared with those estimated with the simple breast model. A discrepancy of 5.4-38.0% was observed. This was consistent with the results obtained from the realistic breast models in the literature. CONCLUSIONS: A 3D detailed breast model with realistic structures in the breast was constructed based on the Chinese female breast parameters. It was used to calculate glandular tissue dose conversion coefficients for mammography. Although the accuracy of the proposed model could not be directly assessed, the consistency of the obtained results with previously performed analyses increases the confidence in the applicability of the proposed model. The proposed model could be used in dose estimation and dose optimization for mammography of Chinese women.

Calculation of conversion coefficients using Chinese adult reference phantoms for air submersion and ground contamination.

The effective and organ equivalent dose coefficients have been widely used to provide assessment of doses received by adult members of the public and by workers exposed to environmental radiation from nuclear facilities under normal or accidental situations. Advancements in phantom types, weighting factors, decay data, etc, have led to the publication of newer results in this regard. This paper presents a new set of conversion coefficients for air submersion and ground contamination (with the use of Geant4) for photons from 15 keV to 10 MeV using the Chinese and International Commission on Radiological Protection (ICRP) adult reference male and female phantoms. The radiation fields, except for energy spectrum at low energies, were validated by the data obtained from the Monte Carlo code YURI. The effective dose coefficients of monoenergetic photons, obtained for the ICRP adult reference phantoms, agree well with recently published data for air submersion and ground contamination with a plane source at a depth of 0.5 g cm-2 in soil, but an average difference of 36.5% is observed for ground surface contamination with the abovementioned radiation field. The average differences in organ equivalent dose coefficients between the Chinese and the ICRP adult reference phantoms are within 6% for most organs, but noticeable differences of up to 70% or even higher are found at photon energies below 30 keV under air submersion. The effective dose coefficients obtained with the Chinese adult reference phantoms are greater than those of the ICRP adult reference phantoms above 30 keV and 0.5 MeV for ground contamination and air submersion, respectively; the average differences from the Chinese adult reference phantoms are about 3.6% and 0.4% in the whole energy range with maximum differences of 31.8% and 27.6% at 15 keV for air submersion and ground contamination respectively. These differences are attributed to anatomical discrepancies in overlying tissue mass of an individual organ and the body mass between the Chinese and the ICRP adult reference phantoms. These monoenergetic photon conversion coefficients are subsequently used to evaluate radionuclides with decay data from ICRP publication 107.

Establishment of the Detailed Breast Model of Chinese Adult Female and Application in External Radiation Protection.

Breast is one of the most sensitive organs to radiation. In 2007, International Commission on Radiological Protection (ICRP) increased the tissue weighting factor for the breast from 0.05 to 0.12, which made the accurate evaluation of breast dose more important. But in the existing human voxel phantom, the structure of breast is not elaborate enough because of the limitation of image resolution used for phantom modeling. This will probably affect the accuracy of breast dose calculated in simulation. Some researches on detailed breast modeling have been carried out, but there is no such research in this field in China. A detailed breast model for Chinese adult female is established in this article using the mathematical modeling method. It is voxelized and merged with the Chinese reference adult female voxel model for breast dosimetry. Dose conversion coefficients of breast gland for external photon exposures in antero-posterior geometry are calculated as an example of the application and the results are compared with those calculated by the old voxel phantom and ICRP reference adult female voxel phantom.

Enhanced volatile fatty acid production from excess sludge by combined free nitrous acid and rhamnolipid treatment.

VFA production from excess sludge (ES) was greatly enhanced by a low-cost and high-efficient treatment: 0.67mg/L free nitrous acid (FNA) pretreatment combined with 0.04g/g TSS rhamnolipid (RL) addition (FNA+RL), which significantly shortened fermentation time to 3days and increased VFA production to 352.26mgCOD/g VSS (5.42 times higher than raw ES). Propionic and acetic acids were the two leading components (71.86% of the total VFA). Mechanism investigation manifested FNA+RL improved the biodegradability of ES, achieved positive synergetic effect on solubilization, hydrolysis and acidification efficiencies, and inhibited methanation. Microbial community distribution further explained the above phenomena. The bacteria related to polysaccharides/protein utilization and VFA generation, including Clostridium, Megasphaera and Proteiniborus, were mainly observed in FNA+RL, whereas gas-forming bacteria Anaerolineae and acid-consuming bacteria Proteobacteria were assuredly suppressed. Besides, Propionibacterineae associated with propionic acid generation was exclusively enriched in sole RL and FNA+RL.

A preliminary risk assessment of potential exposure to naturally occurring estrogens from Beijing (China) market milk products.

This study was conducted to determine the occurrence of the natural steroid hormones estrone (E1), 17α-estradiol (αE2), 17ß-estradiol (ßE2) and estriol (E3) in 38 commercial milk samples obtained from markets in Beijing, China. Liquid Chromatography coupled with tandem mass spectrometry (LC-MS/MS) was employed to determine estrogens levels. The concentrations of E1, αE2, ßE2 and E3 in different milk products varied from 0-146.12 ng/L, 0-70.12 ng/L, 0-31.85 ng/L to 0-2.18 ng/L, respectively. We compared exposures to estrogens through milk consumption with acceptable daily intakes (ADIs) and threshold for toxicological concern (TTC) to determine whether estrogen intakes from milk consumption are larger or smaller than the toxicity-based benchmarks. The combined margin of safety MOS (MOST) for total estrogens are about 72-99, 118-161, 539-1104, for 2-4, 4-7 year-old residential children, and adults, respectively. The lowest MOST for children of 2-4 years old result from comparing total of estrogens with the lowest TTC value (0.15 µg/person/day) (MOS=3.5). The MOS values suggest that the individual and total estrogens that may present in milk are not causing a health risk for the local residents, including young children.

An epidemiological analysis of paediatric burns in urban and rural areas in south central China.

OBJECTIVE: This study aims to analyse the epidemiology of paediatric burns in south central China, illustrate the differences between rural and urban areas, and discern prevention measures to reduce paediatric burns. METHODS: Data were obtained from all paediatric patients admitted to Department of Burns unit of Xiangya Hospital during 2009-2012. A retrospective review was performed, including cause of burn, pre-hospital treatment, place of burn occurrence, anatomical areas involved, extent of burn, date of injury, number of operations, complications, length of hospital stay, hospitalisation cost and cure rate. RESULTS: A total of 278 hospitalised paediatric patients were admitted in this study. The majority (56.47%) were 1-3 years old. Rural patients accounted for 67.99% in total; the ratio of boys to girls was 2.05. Scalding with hot fluids was the most common cause of burns in children (62.59%), followed by flame (17.63), fireworks (9.71%), electricity (5.76%) and other factors such as contact and chemical (4.32%). The living room was the location with the highest frequency of burns in children (53.24%). Burns were more likely to happen in winter and the upper extremities were the most involved anatomic site (53.24%). Total burn surface area (TBSA) ranging from 0% to 9% accounted for 55.4% in total. Rural patients underwent more operations and had longer and costlier hospital stays than urban patients. CONCLUSION: Compared with treatment in urban areas, rural burn patients received less first-aid treatment, underwent more surgery, had more complications and longer and more costly hospital stays. This finding strongly suggests that it is necessary to make more efforts to prevent burns, especially in rural areas.