Modelling of the estimated contributions of different sub-watersheds and sources to phosphorous export and loading from the Dongting Lake watershed, China.

Considerable growth in the economy and population of the Dongting Lake watershed in Southern China has increased phosphorus loading to the lake and resulted in a growing risk of lake eutrophication. This study aimed to reveal the spatial pattern and sources of phosphorus export and loading from the watershed. We applied an export coefficient model and the Dillon-Rigler model to quantify contributions of different sub-watersheds and sources to the total phosphorus (TP) export and loading in 2010. Together, the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area contributed 60.9% of the TP exported from the entire watershed. Livestock husbandry appeared to be the largest anthropogenic source of TP, contributing more than 50% of the TP exported from each secondary sub-watersheds. The actual TP loading to the lake in 2010 was 62.9% more than the permissible annual TP loading for compliance with the Class III water quality standard for lakes. Three primary sub-watersheds-the Dongting Lake Area, the Xiang River, and the Yuan River watersheds-contributed 91.2% of the total TP loading. As the largest contributor among all sources, livestock husbandry contributed nearly 50% of the TP loading from the Dongting Lake Area and more than 60% from each of the other primary sub-watersheds. This study provides a methodology to identify the key sources and locations of TP export and loading in large lake watersheds. The study can provide a reference for the decision-making for controlling P pollution in the Dongting Lake watershed.

[Determination of Bi in Soils and Sediments by Atomic Fluorescence Spectrometry].

A method for determination of the contents of Bi in soils and sediments by atomic fluorescence spectrophotometry (AFS) was established by using aqua regia as the dissolved medium. In this paper, the instrument parameters, load flow and reducing agent concentration were optimized. Compared with microwave digestion and electric heating plate digestion, water bath digestion demonstrated the better digestion efficiency and was most commonly used. Under the optimal experimental conditions, the detection limit (LOD) was 0.01 mg·kg-1 (sample quantity 0.500 0 g, sample volume 50 mL), and the limit of quantitation (LOQ) was 0.04 mg·kg-1. The results were in good agreement with the centified value, and the relative error was -4.7%~-2.0%. For determination of soil and sediment actual samples, the relative standard deviation (RSD) were 2.5%~3.4% and 3.1%~3.4%, respectively, and the recoveries of the method respectively ranged from 97.6%~102% and 99.5%~104%.

Combination of low-intensity pulsed ultrasound and C3H10T1/2 cells promotes bone-defect healing.

AIMS: We systematically investigated the effect of combined use of low-intensity pulsed ultrasound (LIPUS) and bone mesenchymal stem cells C3H10T1/2 on bone-defect healing. METHODS: C3H10T1/2 cells were first induced into a stationary phase by incubation with low fetal bovine serum (5 ml/l) for five days and then sonicated with LIPUS for ten minutes once every day for five consecutive days. The same LIPUS treatment combined with C3H10T1/2 cells, which were incubated in regular fetal bovine serum (10 ml/l) were used to aid femoral fracture healing in Sprague-Dawley rats during four consecutive weeks. C3H10T1/2 cell proliferation activity was detected by MTT assay. Cell-cycle changes were determined, and cell proliferation index was calculated using flow cytometry. Bone reparation was evaluated by X-ray imaging and hematoxylin and eosin (H&E) staining during the healing process. RESULTS: LIPUS promoted C3H10T1/2 cell proliferation, the mechanism of which was possibly the up-regulation of Bmi-1 gene expression. At the end of week two after combined use of LIPUS and C3H10T1/2, the femoral gap was reduced on X-ray images. According to H&E staining results, new bone had homogeneous and similar density compared with normal surrounding bone after combined use of LIPUS and C3H10T1/2. At the end of week four, bone defects could not be observed by X-ray in all four groups and repaired bone substance in all four groups could be observed by H&E staining. CONCLUSIONS: LIPUS treatment effectively promotes C3H10T1/2 cells to enter the growth/split phase from the stationary phase. This process enhances cell proliferation, which consequently promotes bone-defect healing.

Determination of Beryllium in Soil and Sediment by Graphite Furnace Atomic Absorption with a Microwave-Acid Digestion Method.

A method for determination of beryllium in soils and sediments by microwave-acid digestion/graphite furnace atomic absorption (GFAA) is described. In this paper, the working conditions of the instrument are optimized, the drawing of calibration curve is expounded, the pretreatment process of soil and sediments (including microwave heating process and the selection of digestion system) is discussed, and the interference of coexisting elements is examined. The sample was pretreated by microwave digestion parameters using HNO3/ HCl/HF mixed acid system. The method is fast and simple without matrix modifier, and has no interference by coexisting ions, and has high repeatability and reproducibility. Under the optimal experimental conditions, the limit of detection (LOD) is 0.004 9 mg · kg⁻¹ (sample quantity 0.200 0 g, sample volume 25 mL), and the limits of quantitation (LOQ) is 0.20 mg · kg⁻¹. This method is used to measure the standard samples and actual samples, whether in the laboratory, or between laboratories, has good accuracy and precision.

Perceptions of the role of dentists in human papillomavirus and COVID-19 vaccinations: Results of a cross-sectional validated survey of adults.

BACKGROUND: Human papillomavirus (HPV) and COVID-19 are contagious diseases for which effective vaccines exist. Dental care professionals' involvement in vaccination campaigns for these conditions has been proposed, but there is a lack of understanding of dentists' roles in vaccination, specifically assessing patients' attitudes around dentists as vaccinators for HPV and COVID-19. METHODS: Using a cross-sectional design and convenience sampling, a 12-item validated survey was distributed to community members to determine perceptions about dentists' roles in vaccination for HPV and COVID-19. Demographic characteristics, vaccination status, knowledge of the diseases, vaccination intentions, and willingness to receive education about, recommendations for, and administration of vaccine from a dentist were assessed. Responses were analyzed using bivariate and multivariate analysis. RESULTS: Of 618 participants, most were vaccinated previously against HPV and COVID-19 (n = 462 [75.6%] and n = 371 [61.0%], respectively). Participants responded more favorably to dentist involvement in educating, discussing, and administering COVID-19 vaccines than HPV vaccines (P < .05). Participants' knowledge of HPV was found to be low compared with that of COVID-19. There were significant differences across demographic groups, with race most frequently associated with differences in responses to COVID-19 and HPV-related questions. CONCLUSIONS: Formative data to develop interventions to support dentists' participation in vaccination campaigns are provided. Participants' acceptance of COVID-19 vaccination over HPV vaccination may reflect the public awareness of COVID-19 vs HPV due to daily relevance of this disease, or the lack of knowledge about HPV, particularly its oropharyngeal impacts. PRACTICAL IMPLICATIONS: The authors provide evidence to support dentists' involvement in vaccine education and distribution, expanding previous literature into evaluation of a new disease context (COVID-19). Lack of knowledge of HPV may affect willingness to receive the HPV vaccine, presenting an opportunity for education.

Preparation of starch-palmitic acid complexes by three different starches: A comparative study using the method of heating treatment and autoclaving treatment.

Recent research emphasizes the growing importance of starch-lipid complexes due to their anti-digestibility ability, prompting a need to explore the impact of different starch sources and preparation methods on their properties. In this study, starch-palmitic acid (PA) complexes were prepared by three different starches including Tartary buckwheat starch (TBS), potato starch (PTS), and pea starch (PS) by heating treatment (HT) and autoclaving treatment (AT), respectively, and their physicochemical property and in vitro digestibility were systematically compared. The formation of the starch-PA complex was confirmed through various characterization techniques, including scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction. Among the complexes, the PTS-PA complex exhibited the highest complexation index over 80 %, while the PS-PA complex had the lowest rapid digestible starch content (56.49-59.42 %). Additionally, the complexes prepared by AT exhibited higher resistant starch content (41.95-32.46 %) than those prepared by HT (31.42-32.49 %), while the complexes prepared by HT held better freeze-thaw stability and hydration ability than those prepared by AT. This study highlights the important role of starch sources in the physicochemical and digestibility properties of starch-lipid complex and the potential application of AT in the preparation of novel resistant starch.

Big data analysis of water quality monitoring results from the Xiang River and an impact analysis of pollution management policies.

Water pollution prevention and control of the Xiang River has become an issue of great concern to China's central and local governments. To further analyze the effects of central and local governmental policies on water pollution prevention and control for the Xiang River, this study performs a big data analysis of 16 water quality parameters from 42 sections of the mainstream and major tributaries of the Xiang River, Hunan Province, China from 2005 to 2016. This study uses an evidential reasoning-based integrated assessment of water quality and principal component analysis, identifying the spatiotemporal changes in the primary pollutants of the Xiang River and exploring the correlations between potentially relevant factors. The analysis showed that a series of environmental protection policies implemented by Hunan Province since 2008 have had a significant and targeted impact on annual water quality pollutants in the mainstream and tributaries. In addition, regional industrial structures and management policies also have had a significant impact on regional water quality. The results showed that, when examining the changes in water quality and the effects of pollution control policies, a big data analysis of water quality monitoring results can accurately reveal the detailed relationships between management policies and water quality changes in the Xiang River. Compared with policy impact evaluation methods primarily based on econometric models, such a big data analysis has its own advantages and disadvantages, effectively complementing the traditional methods of policy impact evaluations. Policy impact evaluations based on big data analysis can further improve the level of refined management by governments and provide a more specific and targeted reference for improving water pollution management policies for the Xiang River.

A Novel Optical Fiber Terahertz Biosensor Based on Anti-Resonance for The Rapid and Nondestructive Detection of Tumor Cells.

The sensitive and accurate detection of tumor cells is essential for successful cancer therapy and improving cancer survival rates. However, current tumor cell detection technologies have some limitations for clinical applications due to their complexity, low specificity, and high cost. Herein, we describe the design of a terahertz anti-resonance hollow core fiber (THz AR-HCF) biosensor that can be used for tumor cell detection. Through simulation and experimental comparisons, the low-loss property of the THz AR-HCF was verified, and the most suitable fiber out of multiple THz AR-HCFs was selected for biosensing applications. By measuring different cell numbers and different types of tumor cells, a good linear relationship between THz transmittance and the numbers of cells between 10 and 106 was found. Meanwhile, different types of tumor cells can be distinguished by comparing THz transmission spectra, indicating that the biosensor has high sensitivity and specificity for tumor cell detection. The biosensor only required a small amount of sample (as low as 100 µL), and it enables label-free and nondestructive quantitative detection. Our flow cytometry results showed that the cell viability was as high as 98.5 ± 0.26% after the whole assay process, and there was no statistically significant difference compared with the negative control. This study demonstrates that the proposed THz AR-HCF biosensor has great potential for the highly sensitive, label-free, and nondestructive detection of circulating tumor cells in clinical samples.

Scenario analysis of the impacts of socioeconomic development on phosphorous export and loading from the Dongting Lake watershed, China.

Socioeconomic development in lake watersheds is closely related with lake nutrient pollution. As the second largest freshwater lake in China, the Dongting Lake has been experiencing an increase in nutrient loading and a growing risk of eutrophication. This study aimed to reveal the likely impacts of the socioeconomic development of the Dongting Lake watershed on the phosphorous pollution in the lake. We estimated the contributions from different sources and sub-watersheds to the total phosphorous (TP) export and loading from the Dongting Lake watershed under two most likely socioeconomic development scenarios. Moreover, we predicted the likely permissible and actual TP loadings to the Dongting Lake. Under both two scenarios, three secondary sub-watersheds-the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area-are expected to dominate the contribution to the TP export from the Dongting Lake watershed in 2020. Three primary sub-watersheds-the Dongting Lake Area, the Xiang River, and the Yuan River watersheds-are predicted to be the major contributors to the TP loading from the entire watershed. The two scenarios are expected to have a slight difference in TP export and lake TP loading. Livestock husbandry is expected to be the predominant anthropogenic TP source in each of the sub-watersheds under both scenarios. Compared to 2010, permissible TP loading is not expected to increase but actual TP loading is predicted to grow significantly in 2020. Our study provides methodologies to identify the key sources and regions of lake nutrient loading from watersheds with complex socioeconomic context, and to reveal the potential influences of socioeconomic development on nutrient pollution in lake watersheds.

Adsorptive properties of alluvial soil for arsenic(V) and its potential for protection of the shallow groundwater among Changsha, Zhuzhou, and Xiangtan cities, China.

The study area is among Changsha, Zhuzhou, and Xiangtan cities, which was under agricultural use and natural conditions about 10 years ago and now is becoming part of the metropolis because of the urban expansion. This study aims to investigate the mechanisms and capabilities of the local alluvial soil layer for protecting the local shallow groundwater from arsenic pollution by field surveys and batch experiments. The field surveys showed that there was an acidic tendency of the groundwater, and phosphate, nitrate, and arsenic in the groundwater significantly increased comparing to their reference values. It indicates that the disturbance of the former agricultural land due to the change of land use may be responsible for these changes. From the experimental results, the maximum adsorption capacity of the soil for As(V) was as low as 0.334 mg/g, and lower As(V) adsorption capacities were obtained at higher As(V) concentration, higher pH, and lower temperature. The presence of H2PO4- and SiO32- posed negative, while HCO3- slight positive, and SO42-, NO3- and Cl- negligible influences on the As(V) adsorption. The surface-derived organic matter played a negative role in the adsorption process, and low specific surface area influenced adsorption capacity of the soil. The study reveals that the local soil layer shows poor potential for protection of the local shallow groundwater from As(V) pollution, and the change trends of the groundwater environments due to more intensive anthropogenic activities will further weaken this potential and increase the risk of the groundwater contamination.

Treatment effect of low intensity pulsed ultrasound on leukopenia induced by cyclophosphamide in rabbits.

OBJECTIVE: This study aims to examine the effects of low intensity pulsed ultrasound (LIPUS) on leukopenia induced by cyclophosphamide in a rabbit model. METHODS: The leukopenia model in New Zealand rabbit was established by injecting cyclophosphamide into the ear vein. Forty leukopenia model rabbits were randomly allocated to control group (n = 20) and LIPUS group (n = 20). LIPUS group underwent 20 minutes of daily ultrasound treatment at femoral metaphysis for 7 days while control group received sham treatment. Diarrhea rate, mortality and blood cell count were calculated. IgA, IgG and IgM levels were measured by ELISA. Flow cytometry was used to detect CD44, CD49d, and PU.1. HE staining was performed to analyze bone marrow hyperplasia and changes of skin and muscle. RESULTS: LIPUS treatment significantly promoted the proliferation of bone marrow nucleated cells, increased the number of WBC, IgA, IgG and IgM in the peripheral blood, and reduced the diarrhea rate and mortality. The irradiated skin and muscle tissues showed no obvious damages. LIPUS treatment promoted the migration of hematopoietic cells to peripheral blood by decreasing the expression of CD49d and CD44 on the surface of CD34 positive cells. It also promoted the differentiation of hematopoietic stem cells into granulocytes and lymphocytes by decreasing the expression of PU.1. CONCLUSION: LIPUS can be used as a safe and effective clinical treatment for cyclophosphamide induced leukopenia.

[Establishment of New Zealand rabbit models of aplastic anemia].

OBJECTIVE: To screen for the optimal dose of benzene and cyclophosphamide using an orthogonal design for establishment of New Zealand rabbit models of aplastic anemia. METHODS: Following an orthogonal experimental design, the effects of 3 levels of 4 factors, namely the dose of benzene (A), the dose of cyclophosphamide (B), the number of benzene injections (C), and the number of cyclophosphamide injections (D) were tested in the establishment of New Zealand rabbit models of aplastic anemia using a L9 (34) orthogonal table, and the optimal protocol for the model establishment was selected from the 9 experimental groups. Each rabbit received subcutaneous injection of benzene on the back every other day, followed by daily cyclophosphamide injection via the ear vein for prescribed times. The blood routine was examined every 6 days, and before modeling and at 36 days after modeling, a small sample of the femoral bone was collected for bone marrow histopathological examination. RESULTS: Comparison of the white blood cell, erythrocyte and platelet counts among the 9 groups showed successful modeling in Groups 4-9, and daily mean reduction rates of the cell counts in Groups 7, 8, and 9 differed significantly from those in the other groups (P<0.05). In Group 7, bone marrow sections showed low myelodysplasia, reduced hematopoietic tissue, reduced or even absence of megakaryocytes, and increased fat cells. Further observation found that the rabbits in Group 7 had sustained bone marrow suppression, consistent with the clinical characteristics of the disease. CONCLUSION: Stable models of aplastic anemia can be established efficiently in New Zealand rabbits by a combination of 8 subcutaneous injections of benzene at 1.5 mL/kg and 4 intravenous injections of cyclophosphamide at 10 mg/kg.

[Pollution Characteristics Analysis in Shallow Groundwater of Typical Farmland Area, Southern China].

To analyze the characteristics of shallow groundwater pollution in farmland ecosystem in south China and geochemical behavior of major pollutants in the environment, taking the typical farmland in Taihu River Basin as the object, combined with conventional analysis method of the water quality, fluorescence spectrum technology and multivariate statistical analysis method, the characteristics of the water chemistry in shadow groundwater and the distribution of the dissolved organic matter and the heavy metals were studied. The reasons for all the phenomena were researched as well. The result showed that, water body in the study area showed the reducing atmosphere, the main chemical types of shallow groundwater were HCO3-Ca·Na, and compared to the contents of NH3--N and NH2--N, the concentration of NH4+-N was higher. Dissolved organic matter of the shallow groundwater was composed of humic acid, tryptophan and tyrosine. And they were mainly derived from terrestrial and biological source. The distribution was affected by the flow direction of the surface water supplies and groundwater. In the detection of nine kinds of heavy metal elements, the average concentrations of Fe and Cr were higher than the national groundwater environmental quality in class Ⅲ standard. And the contents of Fe, Cr, Mn, Zn elements at some points exceeded the standard. The results showed that fluorescent organic matter characteristics could better reflect the status of shallow groundwater pollution, in which the kind of protein-like substances was closely related to the ammonia nitrogen. The heavy metal elements Cu and Ni were associated with the dissolved organic matter and they were mainly complexed in small molecular fluorescent organic matter.

Permissible value for vanadium in allitic udic ferrisols based on physiological responses of green Chinese cabbage and soil microbes.

Greenhouse experiments were conducted to study the permissible value of vanadium (V) based on the growth and physiological responses of green Chinese cabbage (Brassica chinensis L.), and effects of V on microbial biomass carbon (MBC) and enzyme activities in allitic udic ferrisols were also studied. The results showed that biomass of cabbage grown on soil treated with 133 mg V kg(-1) significantly decreased by 25.1% compared with the control (P < 0.05). Vanadium concentrations in leaves and roots increased with increasing soil V concentration. Contents of vitamin C (Vc) increased by 10.3%, while that of soluble sugar in leaves significantly decreased by 54.0% when soil V concentration was 133 mg kg(-1), respectively. The uptake of essential nutrient elements by cabbage was disturbed when soil V concentration exceeded 253 mg kg(-1). Soil MBC was significantly stimulated by 15.5%, while dehydrogenase activity significantly decreased by 62.8% and urease activity slightly changed at treatment of 133 mg V kg(-1) as compared with the control, respectively. Therefore, the permissible value of V in allitic udic ferrisols is proposed as 130 mg kg(-1).

3D antibody immobilization on a planar matrix surface.

The amount of active capture antibodies immobilized per unit square is crucial to developing effective antibody chips, biosensors, immunoassays and other molecular recognition technologies. In this study, we present a novel yet simple method for oriented antibody immobilization at high density based on the formation of an orderly, organized aggregation of immunoglobulin G (IgG) and staphylococcal protein A (SPA). Following the chelation of His-tag with Ni(2+), antibodies were immobilized on a solid surface in a three-dimensional (3D) manner and exposed the analyte receptor sites well, which resulted in a substantial enhancement of the analytical signal with more than 64-fold increase in detection sensitivity. Pull-down assays confirmed that IgG antibody can only bind to Ni(2+) matrix indirectly via a SPA linkage, where the His-tag is responsible for binding Ni(2+) and homologous domains are responsible for binding IgG Fc. The immobilization approach proposed here may be an attractive strategy for the construction of high performance antibody arrays and biosensors as long as the antibody probe is of mammalian IgG.