Analysis of spatial patterns and influencing factors of farmland transfer in China based on ESDA-GeoDetector.

Farmland transfer is a critical component in facilitating agricultural scale management and improving agricultural production efficiency. This study examines the spatial distribution of farmland transfer in China and identifies the factors influencing it, offering valuable guidance for advancing China's farmland transfer practices. Through the application of mathematical statistics and GIS spatial analysis, the study investigates changes in spatial patterns related to the scale, rate, mode, and recipients of farmland transfer across China's 30 provinces from 2015 to 2020. Geographical detectors are also employed to identify the key factors influencing the extent and pace of farmland transfer. The study reveals that between 2015 and 2020, China's farmland transfer area increased from 29,789 to 37,638 million hectares. Provinces with abundant farmland resources generally experienced larger farmland transfers, while economically developed regions and major grain-producing areas saw higher rates of farmland transfers. The predominant mode of farmland transfer in China was leasing (subcontracting), accounting for over 80% of the total transferred area. Large-scale grain growers and family farms were significant participants in farmland transfers, acquiring approximately 60.1% of the transferred lands, followed by professional cooperatives (21.5%), enterprises (10.4%), and other entities (7.9%). Key factors influencing the farmland transfer area include the "regional farmland area", the "proportion of family farms supported by loans", and the "proportion of non-agricultural population", with explanatory powers of 0.663, 0.319, and 0.225, respectively. Notably, there is a substantial interaction between the "regional farmland area" and factors such as the "proportion of family farms supported by loans" and the "grain yield per unit area", with explanatory powers reaching 0.957 and 0.901, respectively. These findings offer valuable insights for promoting farmland transfer in agriculturally rich regions. Factors affecting the farmland transfer rate include "grain yield per unit area", "GDP per capita", and the "proportion of non-agricultural population", each with an explanatory power above 0.500. Moreover, their interactive explanatory powers with other indicators exceed 0.600, indicating that provinces with high agricultural productivity or economic development levels are more likely to undergo farmland transfer. The paper concludes by proposing strategies and recommendations to promote farmland transfer in both "large agricultural areas" and "metropolitan suburbs."

Statistical Analysis of Morphological Characteristics of Inconel 718 Formed by High Deposition Rate and High Laser Power Laser Cladding.

Laser cladding is one of the emerging additive manufacturing technologies and has been adopted in various industrial fields. In this study, the morphological characteristics of a single clad of Inconel 718 manufactured by coaxial laser cladding with high laser power from 4200 W to 5400 W, powder feeding rate from 25 g/min to 50 g/min, and cladding speed from 20 mm/s to 50 mm/s are studied. The cross-section of the melt pool is analyzed and classified by type into three types: shallow dilution, flat dilution, and fluctuating dilution. Nine parameters are designed to describe the morphological characteristics of the clad, and the corresponding linear regression models are developed to establish a quantitative relationship between the combined process parameters and morphological characteristics. The results indicate that the total area of the cross-section A, the clad area above the substrate Ac, the area of the molten substrate Am, the total height of the cross-section H, the height of the clad above the substrate hc, the penetration depth hm, the clad width W, the dilution ratio D, and the wetting angle θ are determined by complex coupling of energy input and mass accumulation, and they are proportional to PF0.4/V, P0.5F/V, P/F0.2/V0.4, P2F0.6/V, PF0.7/V, P2/F/V0.3, P/V0.8, P/FV0.2, and PF7/V0.8, respectively. The large linear regression coefficients and the analysis residuals indicate the high reliability of the statistical linear regression models. This work aims to provide a comprehensive understanding of the influence of the main processing parameters on the morphological characteristics of the clad, which is of great value in providing a reference and laying a basis for the practical application of laser cladding technology at a high deposition rate.

Prostate tuberculosis mimicking prostate cancer: Case report and literature review.

RATIONALE: Prostate tuberculosis (PTB) has no specific symptoms, or insidious presentation in male reproductive system tuberculosis, and is difficult to detect in the early stage. When PTB develops to the late stage, it leads to disease progression and irreversible organ and tissue damage. At present, the imaging manifestations of prostate tuberculosis vary and are not well known to imaging physicians and urologists. DIAGNOSES AND INTERVENTIONS: This case was a PTB patient, whose main manifestation was elevated serum prostate-specific antigen and the diagnosis was confirmed by ultrasound-guided prostate biopsy. We analyzed the imaging performance of various imaging techniques, and summarized and explored the imaging characteristics reported in the previous literature, with the aim of improving the early detection rate and providing evidence-based practice for early regular antituberculosis treatment in PTB. OUTCOMES: The multiparametric transrectal ultrasound performance of PTB is characteristic, and can be used for the differential diagnosis of prostate cancer causing elevated prostate-specific antigen levels in aged men.

Effect of Laser Beam Profile on Thermal Transfer, Fluid Flow and Solidification Parameters during Laser-Based Directed Energy Deposition of Inconel 718.

The profile of the laser beam plays a significant role in determining the heat input on the deposition surface, further affecting the molten pool dynamics during laser-based directed energy deposition. The evolution of molten pool under two types of laser beam, super-Gaussian beam (SGB) and Gaussian beam (GB), was simulated using a three-dimensional numerical model. Two basic physical processes, the laser-powder interaction and the molten pool dynamics, were considered in the model. The deposition surface of the molten pool was calculated using the Arbitrary Lagrangian Eulerian moving mesh approach. Several dimensionless numbers were used to explain the underlying physical phenomena under different laser beams. Moreover, the solidification parameters were calculated using the thermal history at the solidification front. It is found that the peak temperature and liquid velocity in the molten pool under the SGB case were lower compared with those for the GB case. Dimensionless numbers analysis indicated that the fluid flow played a more pronounced role in heat transfer compared to conduction, especially in the GB case. The cooling rate was higher for the SGB case, indicating that the grain size could be finer compared with that for the GB case. Finally, the reliability of the numerical simulation was verified by comparing the computed and experimental clad geometry. The work provides a theoretical basis for understanding the thermal behavior and solidification characteristics under different laser input profile during directed energy deposition.

Role of Surface-Active Element Sulfur on Thermal Behavior, Driving Forces, Fluid Flow and Solute Dilution in Laser Linear Welding of Dissimilar Metals.

Understanding heat and mass transfer and fluid flow in the molten pool is very helpful in the selection and optimization of processing parameters, and the surface-active element has an important effect on the heat and mass transfer in laser welding of dissimilar metals. A three-dimensional (3D) numerical model coupled with a sub-model of surface tension, which considers the influence of local temperature and the concentration of surface-active element sulfur at the gas/liquid surface, is used to analyze the thermal behavior, driving forces, fluid flow, and solute dilution during laser linear welding of 304SS and Ni. The relationship between surface tension, driving forces, and the temperature coefficient of surface tension with the spatial distribution of temperature and the surface-active element sulfur is quantitatively analyzed. The simulation results show that the molten pool is fully developed at 45 ms, and the collision of inward and outward convection, with the maximum velocity reaching 1.7 m/s, occurs at the isotherm with a temperature between 2200 K and 2500 K. The temperature-gradient term and concentration-gradient term of surface shear stress play different roles in different positions of the free surface. The local sulfur concentration changes the temperature sensitivity of the surface tension at different sides of the free surface and further determines the transition of convection. Complex fluid flow promotes solute dilution, and the distribution of solute becomes uniform from the front to the rear of the molten pool. The Ni element is transferred to 304SS mainly at the rear side. The work provides theoretical support for the control of joint quality by changing the content of surface-active elements in dissimilar welding.

Proteomic profile of polar filament and polar tube from fungal pathogen microsporidium Nosema bombycis provides new insights into its unique invasion organelle.

Microsporidium is a kind of intracellular fungal pathogen that greatly threatens the human health, breeding industry, and food security. All members of microsporidia possess a unique, highly specialized invasion organelle, described as the polar filament. Like "reversing a finger of gloves", the polar filament discharges out of mature spores to transform as the polar tube, and pathogenic sporoplasm is transported to host cell through polar tube to complete infection. During the invasion process, the structure of polar filament and polar tube has changed, so does the protein composition on them? In this study, we firstly proposed a purification method for polar filament and polar tube from microsporidium Nosema bombycis which was infected silkworm Bombyx mori, and it was also found that the structure of polar filament and polar tube was obviously different. Therefore, the proteome of these two structures was comparatively analyzed. A total of 881 and 1216 proteins were respectively identified from the polar filament and polar tube. Ten potential novel polar tube proteins (PTPs) were screened, providing a reference for the novel PTPs identification. Compared with the polar filament, there were 35 upregulated and 41 downregulated proteins on the polar tube. GO and KEGG pathway analysis of all proteins from the polar filament and polar tube provided us with a profound understanding for the microsporidian germination process, which was of great significance for clarifying the infection mechanism of microsporidia. SIGNIFICANCE: Microsporidia are obligate intracellular parasites that infect a wide variety of hosts, including humans. The polar filament is a unique invasion organelle for microsporidia, and it is also one of the important indexes of microsporidian taxonomy. The polar tube is deformed from the primitive polar filament in mature spores. During the germination, the polar filament turns into a polar tube, like "reversing a finger of gloves", through which pathogenic sporoplasm is transported to host cells to complete infection. Since the structure of the polar filament and polar tube has changed, what about their protein composition? In this study, it was the first time to purify the polar filament and the polar tube from microsporidium Nosema bombycis that was infected silkworm Bombyx mori, which provided new insights for studying the invasion organelle of microsporidia. Comparing the fine structure of polar filament and polar tube, we found that their structure was obviously different. Therefore, the protein composition of these two structures is supposed to be varied. In this case, the proteome of these two structures was comparatively analyzed. A total of 881 and 1216 proteins were respectively identified from the polar filament and polar tube. Ten potential novel polar tube proteins (PTPs) were screened, providing a reference for the novel PTPs identification. Compared with the polar filament, there were 35 upregulated and 41 downregulated proteins on the polar tube. GO and KEGG pathway analysis of all proteins from the polar filament and polar tube provided us with a profound understanding for the microsporidian germination process, which was of great significance for clarifying the infection mechanism of microsporidia.

Hole Morphology and Keyhole Evolution during Single Pulse Laser Drilling on Polyether-Ether-Ketone (PEEK).

Polyether-ether-ketone (PEEK), with its superior mechanical, chemical, and thermal properties, as well as high biocompatibility, has been used in aerospace, electronics, and biomedical applications. In this paper, a large number of experiments of single-pulse laser drilling on PEEK were performed to analyze the hole morphology and keyhole evolution, which were characterized by an optical microscope, charge-coupled device (CCD), and high-speed camera. A novel method is proposed to observe and measure the dimension of the processed hole rapidly right after laser drilling for special polymer materials with wear-resistance and non-conductivity. Morphological characteristics of holes are presented to illustrate the effect of pulse width and peak power on hole depth, hole diameter, and aspect-ratio. The obtained maximum drilling depth was 7.06 mm, and the maximum aspect-ratio was 23. In situ observations of the dynamic process of laser drilling, including the keyhole evolution together with ejection and vaporization behavior, were also carried out. The keyhole evolution process can be divided into three stages: rapid increment stage (0−2 ms) at a rate of 2.1 m/s, slow increment stage (2−4 ms) at a rate of 0.3 m/s, and stable stage (>4 ms). Moreover, the variation of dimensionless laser power density with the increase in pulse width was calculated. The calculated maximum drilling depth based on energy balance was compared with the experimental depth. It is proven that the laser−PEEK interaction is mainly influenced by a photothermal effect. Ejection is the dominant material-removal mechanism and contributes to over 60% of the depth increment during the rapid increment stage, while vaporization is dominant and contributes to about 80% of the depth increment during the slow increment stage. The results reveal the material removal mechanism for single-pulse laser drilling on PEEK, which is helpful to understand the dynamic process of keyhole evolution. This not only provides a processing window for future laser drilling of PEEK but also gives a guide for the manufacturing of other polymers.

[Correlation between conventional ultrasound features and BRAFV600E gene mutation and central lymph node metastasis in thyroid papillary carcinoma].

Objective:To investigate whether central lymph node metastasis（CLNM） in the central region of thyroid papillary carcinoma（PTC） is related to conventional ultrasound features of the primary lesion and BRAFV600E gene mutation. Methods:A total of 300 patients with PTC confirmed by surgical pathology and central lymph node dissection in the First Affiliated Hospital of Jinzhou Medical University from October 2019 to June 2021 were collected. The subjects were divided into the metastatic group and the non-metastatic group according to whether CLNM occurred. The correlation was determined by analyzing the conventional ultrasound characteristics and BRAFV600E gene test results of the two groups of patients. Results:Among 300 PTC patients, 120（40%） had CLNM. Univariate analysis showed that there were statistically significant differences between groups in gender, nodule maximum diameter line, number of lesions, boundaries, morphology, aspect ratio, proximity to the membrane, calcification and BRAFV600E gene mutation（P<0.05）. Logistic multivariate regression analysis showed that gender, maximum diameter line, aspect ratio, proximity to the membrane, microcalcification and BRAFV600E were the risk factors for CLNM in PTC patients（P<0.05）. ROC curve showed that when the maximum diameter was 8.5 mm, the Yooden index was the maximum. Conclusion:When the risk factors of male, maximum diameter ≥8.5 mm, aspect ratio ≥1, microcalcification, proximity to capsule and BRAFV600E（+） appear in PTC patients, high attention should be paid to preventive CLN dissection as soon as possible.

[Correlation of conventional ultrasound features and related factors with BRAFV600E gene mutation in papillary thyroid carcinoma].

Objective:To investigate the correlation of conventional ultrasound features and related factors with BRAFV600E gene mutation in papillary thyroid carcinoma（PTC）. Methods:A total of 266 nodules in 208 patients with PTC confirmed by operation and pathology in First Affiliated Hospital of Jinzhou Medical University from October 2019 to March 2021 were selected. BRAFV600E gene was detected by real-time fluorescence PCR quantitative technique after operation. According to the results of gene detection, the patients were divided into gene mutation positive group and gene mutation negative group. The routine ultrasound features and clinical data of the patients were collected, and the correlation with BRAFV600E gene mutation was analyzed. Results:Among the 266 samples, 188 cases（70.7%） had gene mutation. Univariate analysis showed that there were significant differences in age, nodular edge, capsule boundary, microcalcification and abnormal cervical lymph nodes between the two groups（P<0.05）. The results of Logistic multivariate regression analysis showed that age, nodular margin and abnormal cervical lymph nodes were independent influencing factors of BRAFV600E gene mutation in patients with PTC. ROC curve showed that when the age was 46.5 years old, the Youden index was the highest. Conclusion:BRAFV600E gene mutation is associated with age≤46.5 years old, uneven edge of nodules and abnormal lymph nodes in neck in patients with PTC. The above characteristics can be used to evaluate BRAFV600E gene mutation and have certain guiding significance for clinical diagnosis, treatment and prognosis.

[Clinical and ultrasonic features of papillary thyroid microcarcinoma and risk factors for central lymph node metastasis].

Objective:To investigate the clinical and ultrasonic features of papillary thyroid microcarcinoma （PTMC） and the risk factors of central lymph node metastasis （CLNM）, to provide help for individualized treatment. Methods:One hundred and eighty-five patients with PTMC confirmed by surgery and pathology and underwent prophylactic CLN dissection were retrospectively analyzed. According to lymph node metastasis, patients were divided into metastasis group and non metastasis group. The size, shape, echo, aspect ratio, edge, protruding capsule, nodule location, calcification and calcification were analyzed. The relationship between clnm and ultrasonographic features, sex, age, single/multiple, whether or not with Hashimoto thyroiditis was analyzed. Results:Among 185 patients with PTMC, 55 cases had lymph node metastasis, and the metastasis rate was 30.0%. In univariate analysis, clnm of PTMC was significantly correlated with gender, age, tumor size, protruding capsule, type of calcification and single / multiple （all P<0.05）. In multivariate logistic regression analysis, tumor size, single/multiple, protruding capsule, gender and age were the risk factors of clnm. According to the ROC curve, when the age was 49.5 years old and the mass size was 4.8 mm, the diagnostic test yoden index reached the maximum value. Conclusion:When the risk factors of male, ≤49.5 years old, tumor size≥4.8 mm, multiple and protruding capsule appeared in PTMC patients, preventive CLN clearance should be taken actively.

[Effects of root extract of host plants on seed germination and haustorium formation of Cistanche deserticola]. / å¯„ä¸»æ¤ç‰©æ ¹æµ¸ææ¶²å¯¹è‚‰è‹è“‰ç§å­èŒå‘åŠå¸å™¨å½¢æˆçš„å½±å“.

We examined the effects of root extracts of Haloxylon ammodendron and Beta vulgaris in Chenopodiaceae extracted by water and ethanol on seed germination and haustorium formation of Cistanche deserticola by filter paper culture dish method. The results showed that only adding root extract had no effect on seed germination and haustorium formation of C. deserticola. The germination rate of C. deserticola seeds treated by adding 10 mg·kg-1 gibberellin to the root extracted by ethanol was not significantly different from that of the control (GA3), whereas those treated by adding gibberellin to the ethanol extract of two kinds of host root was increased by more than 10 times. The germination rate of C. deserticola seeds in the treatment with adding 1 mg·kg-1 fluridone (FL) to root extract was not significantly different from that in the control with only fluridone, while those in the treatment with B. vulgaris root water extraction was the highest (39.4%). Compared to the treatment of adding gibberellin to the root extract, the germination rate of C. deserticola seeds was only increased. When FL was added to the host root extract, the haustorium was formed on the germination tube, with the formation rate of the ethanol extraction group being the highest (16.2%). Seed germination rate of C. deserticola increased to 52.3% when GA3 and FL were added to the ethanol extract of H. ammodendron, but the formation rate of haustorium was not different from that of FL treatment. Only 6.7% of the seed formation haustorium in the control was significantly lower than that in FL treatment. There were differences in the position and shape of the haustorium of C. deserticola seeds under different treatments. The haustorium produced by adding the extract of the host root mostly appeared at the top of the bud tube, and many papillae raised into claws. The haustorium of FL treatment without adding the extract of the host root mostly appeared at the bottom or the top of the bud tube splitting. The results indicated that ethanol extraction and water extraction could extract the substances that could promote the formation of C. deserticola seeds haustorium from the host root, but did not affect seed germination. GA3 and FL could significantly improve the germination rate of C. deserticola seeds, but the formation of the haustorium was affected by some substances in the host root extract.

Effect of high-quality nursing intervention on the psychological disorder in patients with gastric cancer during perioperative period: A protocol of systematic review and meta-analysis.

BACKGROUND: This study will be proposed for investigating the effects of high-quality nursing intervention (HQNI) on the psychological disorder in patients with gastric cancer during perioperative period (GC-PPP). METHODS: A cumulative search from inception up to the March 31, 2020 will be performed in the following databases: Cochrane Library, MEDLINE, EMBASE, Web of Science, VIP database, and China National Knowledge Infrastructure. We will search all potential studies from those electronic databases regardless their language and publication status. We will only consider randomized controlled trials (RCTs) for inclusion, which explores the effect of HQNI on the psychological disorder in patients with GC-PPP. Study identification, information extraction, and study quality appraisal will be independently and respectively done by 2 researchers. Any different opinions between 2 researchers will be disentangled by a third researcher after discussion. Cochrane risk of bias tool will be used for study quality assessment, and RevMan 5.3 software will be utilized for statistical analysis. RESULTS: This study will provide a high-quality synthesis of psychological disorder outcomes to evaluate the effects and safety of HQNI for patients with GC-PPP. CONCLUSION: The findings of this study will provide reference and evidence to appraise whether HQNI is an effective on the psychological disorder in patients with GC-PPP STUDY REGISTRATION NUMBER:: INPLASY202040080.

A novel versatile yolk-shell nanosystem based on NIR-elevated drug release and GSH depletion-enhanced Fenton-like reaction for synergistic cancer therapy.

In this study, a versatile doxorubicin (DOX)-loaded yolk-shell nano-particles (HMCMD) assembled with manganese dioxide (MnO2) as the core and copper sulfide (HMCuS) as the mesoporous (∼ 6.4 nm) shell, was designed and synthesized. The resulting HMCMD possess excellent photothermal conversion efficiency. The DOX release from the yolk-shell nanoparticles could be promoted by laser irradiation, which increased the chemotherapy of DOX. Meanwhile, Mn2+ could be released from the HMCMD through a redox reaction between MnO2 and abundant glutathione (GSH) in tumor cells. The released Mn2+ could promote the decomposition of the intracellular hydrogen peroxide (H2O2) by Fenton-like reaction to generate the highly toxic hydroxyl radicals (·OH), thus exhibiting the effective chemodynamic therapy (CDT). Additionally, the efficiency of Mn2+-mediated CDT could be effectively enhanced by NIR irradiation. Further modification of polyethylene glycol (PEG) would improve the water solubility of the HMCMD to promote the uptake by MCF-7 cells. Hence, the HMCMD with synergistic effects of chemotherapy and chemodynamic/photothermal therapy would provide an alternative strategy in antitumor research.

Titanium and zirconium release from titanium- and zirconia implants in mini pig maxillae and their toxicity in vitro.

OBJECTIVE: Titanium (Ti)- and Zirconia (ZrO2)-implants in mini pig maxillae were compared with respect to Ti/zirconium (Zr) release into the surrounding bone tissues, the resulting short term tissue responses and the potential toxicity. METHODS: Ti/Zr release from Ti- and ZrO2-implants in mini pig maxillae was determined with inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). The spatial distribution of Ti and Zr in maxilla tissues near the implant surface was assessed with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). A histological analysis was performed to investigate the tissue responses after 12 weeks of implantation. The cytotoxicity and DNA damage of Ti particles and ZrO2 particles were studied with XTT and Comet assay. RESULTS: The mean Ti content in the bone adjacent to Ti-implants was 1.67 mg/kg-bone weight. The highest Ti content detected was 2.17 mg/kg-bone weight. The mean Zr content in the bone adjected to ZrO2-implants was 0.59 mg/kg-bone weight. The highest Zr content was 0.75 mg/kg-bone weight. The spatial distribution of the Ti and Zr in bone showed mainly a higher intensity of Ti and Zr close to the screw thread outer tip rather. Histological analysis indicated that near both implant-types signs of bone marrow fibrosis were present. EC50 of commercially available ZrO2-nanoparticles (NPs, <100 nm) and ZrO2-microparticles (MPs, <5 µm) was 13.96 mg/ml and 80.99 mg/ml, respectively. ZrO2-NPs and ZrO2-MPs can induce DNA damage at 70 µg/ml and 810 µg/ml, respectively. SIGNIFICANCE: After 12-weeks of implantation, increased concentrations of Ti and Zr can be detected in bone/tissues near Ti- and ZrO2-implants in mini pig maxillae. Ti content released from Ti-implants is two times higher than the Zr content released from ZrO2-implants. ZrO2-NPs showed lower cytotoxicity and DNA damage compared to results reported for Ti-NPs in human cells.

Microstructure and Corrosion Resistance of Laser-Welded Crossed Nitinol Wires.

Laser welding has been considered to be one of the most promising joining processes for Nitinol medical device manufacturing. Presently, there is still a limited understanding about how laser welding affects the microstructure and the resultant corrosion behaviors. This work aimed to reveal the microstructural factors that influence the corrosion resistance of laser-welded crossed Nitinol joints. The microstructures within various zones of the joints were characterized by using transmission electron microscopy (TEM), and the corrosion behaviors of the joints in 0.9% NaCl and Hank's solutions were studied. The base metal exhibits a single austenite (B2) phase and the highest corrosion resistance. The phase constituent of the fusion zone is the coexistence of the B2 matrix and some precipitates (T2Ni, TiNi3, and Ti3Ni4 particles), resulting in a slight decrease in corrosion resistance. The heat affected zone (HAZ) shows the austenite matrix but with the precipitation of R-phase, which considerably reduces the corrosion potential, making it the weakest zone.

Ratcheting Strain and Microstructure Evolution of AZ31B Magnesium Alloy under a Tensile-Tensile Cyclic Loading.

In this paper, studies were conducted to investigate the deformation behavior and microstructure change in a hot-rolled AZ31B magnesium alloy during a tensile-tensile cyclic loading. The relationship between ratcheting effect and microstructure change was discussed. The ratcheting effect in the material during current tensile-tensile fatigue loading exceeds the material's fatigue limit and the development of ratcheting strain in the material experienced three stages: initial sharp increase stage (Stage I); steady stage (Stage II); and final abrupt increase stage (Stage III). Microstructure changes in Stage I and Stage II are mainly caused by activation of basal slip system. The Extra Geometrically Necessary Dislocations (GNDs) were also calculated to discuss the relationship between the dislocation caused by the basal slip system and the ratcheting strain during the cyclic loading. In Stage III, both the basal slip and the {11-20} twins are found active during the crack propagation. The fatigue crack initiation in the AZ31B magnesium alloy is found due to the basal slip and the {11-20} tensile twins.

Cytotoxicity and DNA double-strand breaks in human gingival fibroblasts exposed to eluates of dental composites.

OBJECTIVE: Previously, single composite components were used to study cytotoxicity and induction of DNA double-strand breaks (DNA-DSBs) of dental composite resins. In the present study, cytotoxicity and induction of DNA-DSBs in human gingival fibroblasts (HGFs) were investigated with dental composite eluates consisting of multiple components. The eluates were qualified and quantified. METHODS: The composites Esthet.X® HD, Venus®, X-tra fil®, CLEARFIL™ AP-X, Admira® Fusion and QuiXfil® were polymerized and immersed into Dulbecco's modified Eagle's medium (DMEM) for 72h. Subsequently, HGFs were incubated with the corresponding composite eluates. The cell viability of HGFs was obtained from an XTT assay. DNA-DSBs were determined using a γ-H2AX assay. The qualification and quantification of eluates were performed by gas chromatography/mass spectrometry (GC/MS). RESULTS: HGFs exposed to the eluates of all investigated composites showed no significant loss of cell viability, compared to negative control. Significant DNA-DSBs induction could be found in HGFs exposed to the eluates of Esthet.X® HD (0.43±0.05 foci/cell) and Venus® (0.39±0.04 foci/cell), compared to control (0.22±0.03 foci/cell). A total of 12 substances were detected from the investigated composite eluates. Five of them were methacrylates: tetraethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), ethyleneglycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA). The highest concentration of HEMA (110.5µM), HPMA (86.08µM) and TMPTMA (4.50µM) was detected in the eluates of QuiXfil®. The highest concentration of TEGDMA was 1080µM in Venus® eluates and the highest concentration of EGDMA was 3.18µM in Esthet.X® HD eluates. SIGNIFICANCE: Significant DNA-DSBs induction can be found in HGFs exposed to the eluates of Esthet.X® HD and Venus®. The interactive effects among released (co)monomers and additives may influence the cytotoxicity and induction of DNA-DSBs, compared to exposure with single composite component.

Effects of antioxidants on DNA double-strand breaks in human gingival fibroblasts exposed to dental resin co-monomer epoxy metabolites.

OBJECTIVE: Eluted dental resin co-monomers can be metabolized to intermediate methacrylic acid (MA) and, further, to epoxy metabolites. Antioxidants have been studied previously, with the intention of decreasing the DNA double-strand breaks (DNA-DSBs) in human gingival fibroblasts (HGFs). In this study, the effects of the antioxidants, ascorbic acid (Asc) and N-acetylcysteine (NAC), were investigated on co-monomer metabolite-induced DNA-DSBs. METHODS: HGFs were incubated with MA, 2,3-epoxy-2-methyl-propionicacid-methylester (EMPME) and 2,3-epoxy-2-methylpropionic acid (EMPA), respectively, in the presence or absence of antioxidants (Asc or NAC). EC50 Values were obtained from an XTT-based viability assay. DNA-DSBs were determined using a γ-H2AX assay. RESULTS: The cytotoxicity of the compounds could be ranked in the following order (mean±SEM; n=4): EMPA>EMPME>MA. The average number of DSBs-foci/cell induced by each substance at EC50-concentration could be ranked in the following order (mean±SD; n=4): EMPA>EMPME>MA. EMPA (1.72mM) and EMPME (2.58mM) induced the highest number of DSBs-foci, that is 21-fold and 13-fold, respectively, compared to control (0.48±0.08 foci/cell). The addition of Asc (50; 100; 200µM) or NAC (50; 100; 200; 500µM) to MA (15.64; 5.21mM), EMPME (2.58mM), and EMPA (1.72; 0.57mM) significantly reduced the number of foci/cell in HGFs. The highest reduction could be found in HGFs with 1.72mM EMPA, the addition of NAC (50; 100; 200; 500µM) induced a 15-fold, 17-fold, 14-fold and 14-fold lower number of DSBs-foci/cell, respectively. SIGNIFICANCE: Dental co-monomer epoxy metabolites, EMPME and EMPA, can induce DNA-DSBs. The addition of antioxidants (Asc or NAC) leads to reduction of DNA-DSBs, and NAC leads to more prominent reduction of DNA-DSBs compared to Asc.

[Multi-organ lesions of C57BL/6J mouse models with immune-mediated Sjogren's syndrome].

Objective To observe multi-organ damages at different stages in immune-mediated mouse models of Sjogren's syndrome. Methods Eighty C57BL/6J mice were divided randomly into 2 groups, a blank control group and a model group. Sjogren's syndrome was induced in the 40 mice in the latter group by immune injury. Every 10 mice were killed at 4, 6, 8 and 10 weeks. The submandibular gland, thymus, lung, spleen and kidney were isolated under sterile condition. HE staining was used to observe the pathological changes of the organs under a light microscope. Results Compared with the blank control group, the organs of the model group appeared obvious pathological changes since the 6th weeks, which were characterized by submandibular gland damage and infiltrating lymphocytes, as well as the damages of the lung, kidney, spleen and other organs. The most severe damage was observed at the 8th and 10th week. Conclusion C57BL/6J mouse models of Sjogren's syndrome show the characteristics of multi-system damage, especially obvious at the 8th weeks.