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Laser surface quenching was conducted on the 1.0C-1.5Cr steel with different initial microstructures. The effects of initial microstructure on the cementite dissolution and grain size were studied, and the distributions of temperature and stress were simulated. The results indicated that the thickness of hardened layer was larger when the initial microstructure is martensite, which is mainly because the martensite-to-austenite transformation is displacive transformation during laser heating. Within hardened layer, the volume fraction of cementite (VFC) increases with the increase of depth. For the initial microstructure composed of ferrite matrix and cementite, the refining of cementite will facilitate its dissolution, and within hardened layer, mean diameter of cementite (MDC) decreases first and then increases with the increase of depth. For the initial microstructure composed of martensite matrix and cementite, the MDC changes slightly at deeper position of hardened layer. Tensile stress will form in the heat affect zone, and due to the high sensitivity to tensile stress, the impact resistance and bending properties of spheroidized microstructure are worse after laser surface quenching. Under identical laser parameters, the impact absorbed energy of spheroidized microstructure is about 50% of tempered sorbite and 60% of martensitic microstructure, and its bending strength is about 60% of tempered sorbite, and 40% of martensitic microstructure. The impact absorbed energy can be increased by at least 26% through preheating at 160 °C. In addition, the refining of initial martensitic microstructure will enhance bending resistance. [ABSTRACT FROM AUTHOR]

Most Simultaneous Localization and Mapping (SLAM) methods assume that environments are static. Such a strong assumption limits the application of most visual SLAM systems. The dynamic objects will cause many wrong data associations during the SLAM process. To address this problem, a novel visual SLAM method that follows the pipeline of feature-based methods called DM-SLAM is proposed in this paper. DM-SLAM combines an instance segmentation network with optical flow information to improve the location accuracy in dynamic environments, which supports monocular, stereo, and RGB-D sensors. It consists of four modules: semantic segmentation, ego-motion estimation, dynamic point detection and a feature-based SLAM framework. The semantic segmentation module obtains pixel-wise segmentation results of potentially dynamic objects, and the ego-motion estimation module calculates the initial pose. In the third module, two different strategies are presented to detect dynamic feature points for RGB-D/stereo and monocular cases. In the first case, the feature points with depth information are reprojected to the current frame. The reprojection offset vectors are used to distinguish the dynamic points. In the other case, we utilize the epipolar constraint to accomplish this task. Furthermore, the static feature points left are fed into the fourth module. The experimental results on the public TUM and KITTI datasets demonstrate that DM-SLAM outperforms the standard visual SLAM baselines in terms of accuracy in highly dynamic environments. [ABSTRACT FROM AUTHOR]

One new Zn(Ⅱ) metal–organic framework, [Zn 3 (tib) 2 (BPT) 2 ·7H 2 O (ZZIT-1) [ZZIT-1 = Zhengzhou Institute of technology, tib = 1,3,5-tris(1-imidazolyl)benzene, H 3 BPT = biphenyl-3,4′,5-tricarboxylic acid], has been synthesized and characterized. ZZIT-1 is a two-fold interpenetrating 3D framework structure. The gas/vapor adsorption behavior and luminescence of the complex have been studied. Notably, ZZIT-1 can selectively adsorb CO 2 over N 2 , and MeOH over EtOH, and these adsorption results have been corroborated by theoretical calculations. Most interestingly, ZZIT-1 shows unique selectivity for the detection of acetone through a fluorescence quenching mechanism in the solid state at room temperature. Image 1 • One new Zn(Ⅱ)-MOF with mixed organic ligands has been obtained. • The framework shows two-fold interpenetrating 3D framework structure. • Luminescence sensing and gas/vapor sorption properties of the framework were investigated. [ABSTRACT FROM AUTHOR]

The 1.0C-1.5Cr steel was subjected to conventional quenching and laser surface quenching treatment. A process combing double quenching and laser surface quenching was proposed for enhancing surface hardness and obtaining finer microstructure. The cementite dissolution and grain growth behavior in the austenitizing process of single quenching, double quenching, and laser surface quenching were studied. The results indicated that compared with single quenching, mean diameter of undissolved cementite particles (UCP) was much finer in double quenching, and the final prior austenite grain size (PAGS) could be decreased by nearly 40% to about 4.5 μm. Both grain and cementite particles near the surface will coarsen after laser surface treatment. Compared with single quenching, the PAGS within hardened layer can be decreased by at least 11% through double quenching, and the mean diameter of UCP at the bottom of hardened layer can be decreased by about 20%. Compared with conventional quenching, surface hardness was enhanced by about 20% through laser surface quenching, contributing to the wear resistance. However, the hard and brittle surface layer tends to be crack source during the impact process, leading to the deterioration of final impact toughness. Under the identical laser parameters, the impact absorbed energy is similar in both single and double quenching, which is about 25% of that before laser surface quenching. The impact absorbed energy can be increased from 22J to 28J by preheating at 160 °C during the laser surface quenching. [ABSTRACT FROM AUTHOR]

A measurement method of 85Kr using an internal gas proportional counter (IGPC) is presented in this study. The operation conditions of the IGPC were determined and optimized, including the operating voltage, pressure, sample volume, interference from other gas components such as nitrogen or air, and mitigation of the memory effect. The IGPC was calibrated using certified standards, and the detection efficiency was approximately 58% for typical samples. A lower limit of detection of approximately 0.11 MBq/m3(Kr) was achieved after counting for 5 h with 1 mL pure Kr, corresponding to the atmospheric activity concentration of 0.18 Bq/m3 (air). It was shown that the IGPC could be used effectively for measuring 85Kr. • A measuring setup of krypton-85 with an internal proportional counter is described. • Operating conditions were tested and optimized. • The performance of the method is presented. [ABSTRACT FROM AUTHOR]

Gap junctions (Gjs), formed by specific protein termed connexins (Cxs), regulate many important cellular processes in cellular immunity. However, little is known about their effects on humoral immunity. Here we tested whether and how Gj protein connexin43 (Cx43) affected antibody production in spleen cells. Detection of IgG in mouse tissues and serum revealed that wild-type (Cx43+/+) mouse had a significantly higher level of IgG than Cx43 heterozygous (Cx43+/−) mouse. Consistently, spleen cells from Cx43+/+ mouse produced more IgG under both basal and lipopolysaccharide (LPS)-stimulated conditions. Further analysis showed that LPS induced a more dramatic activation of ERK and cell proliferation in Cx43+/+ spleen cells, which was associated with a higher pro-oxidative state, as indicated by the increased NADPH oxidase 2 (NOX2), TXNIP, p38 activation and protein carbonylation. In support of a role of the oxidative state in the control of lymphocyte activation, exposure of spleen cells to exogenous superoxide induced Cx43 expression, p38 activation and IgG production. On the contrary, inhibition of NOX attenuated the effects of LPS. Collectively, our study characterized Cx43 as a novel molecule involved in the control of spleen cell activation and IgG production. Targeting Cx43 could be developed to treat certain antibody-related immune diseases. [ABSTRACT FROM AUTHOR]

Background: There is growing literature suggesting a link between vitamin D and asthma lung function, but the results from systematic reviews are conflicting. We conducted this meta-analysis to investigate the relation between serum vitamin D and lung function in asthma patients.Methods: Major databases, including OVID, MEDLINE, Web of Science and PUBMED, were searched until 10th October 2018. All published observational studies related to vitamin D and asthma were extracted. All meta-analyses were performed using Review Manager 5.3.5.Results: This quantitative synthesis found that asthma patients with low vitamin D levels had lower forced expiratory volume In 1 s (FEV1) (mean difference (MD) = - 0.1, 95% CI = - 0.11 to - 0.08,p < 0.01;I2 = 49%, p = 0.12) and FEV1% (MD = - 10.02, 95% CI = - 11 to - 9.04, p < 0.01; I2 = 0%, p = 0.82) than those with sufficient vitamin D levels. A positive relation was found between vitamin D and FEV1 (r = 0.12, 95% CI = 0.04 to 0.2, p = 0.003; I2 = 59%,p = 0.01), FEV1% (r = 0.19, 95% CI = 0.13 to 0.26, p < 0.001; I2 = 42%, p = 0.11), forced vital capacity (FVC) (r = 0.17, 95% CI = 0.00 to 0.34, p = 0.05; I2 = 60%, p = 0.04), FEV1/FVC (r = 0.4, 95% CI = 0.3 to 0.51, p < 0.001; I2 = 48%, p = 0.07), and the asthma control test (ACT) (r = 0.33, 95% CI = 0.2 to 0.47, p < 0.001; I2 = 0%, p = 0.7). Subgroup analysis indicated that the positive correlation between vitamin D and lung function remained significant in both children and adults.Conclusions: Our meta-analysis suggested that serum vitamin D levels may be positively correlated with lung function in asthma patients. Future comprehensive studies are required to confirm these relations and to elucidate potential mechanisms. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses metallogenic regularity of hydrothermal uranium deposits in the migmatite of the Kangdian Axis. It mentions that the uranium mineralization is found in the iron oxide copper gold deposit. It also reveals that spatial distribution of uranium mineralization is controlled by migmatite that related to ductile shear zones.

In this paper, we intensively collected atmospheric particulate matter (PM) with different diameters (size ranges: <0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2, and >7.2 μm) in Lhasa during the monsoon and non-monsoon seasons. The results clearly showed that the concentrations of PM, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) during the non-monsoon season were much higher than the concentrations during the monsoon season. During the monsoon season, a bimodal size distribution of the OC and WSOC, which were at <0.49 μm and >7.2 μm, respectively, and a unimodal size distribution at <0.49 μm for the EC were observed. However, during the non-monsoon season, there was a trimodal size distribution of the OC and WSOC (<0.49 μm, 1.5–3.0 μm, and >7.2 μm), and a unimodal size distribution of the EC (<0.49 μm). Possible sources of the carbonaceous components were revealed by combining the particle size distribution and the correlation analysis. OC, EC, and WSOC were likely from the photochemical transformation of biogenic and anthropogenic VOC, and the incomplete combustion of biomass burning and fossil fuels at <0.49 μm, whilst they were also likely to be from various types of dust and biogenic aerosols at >7.2 μm. OC and WSOC at 1.5–3.0 μm were likely to have been from the burning of yak dung and photochemical formation. The above results may draw attention in the public and scientific communities to the issues of air quality in the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

isolation, structure elucidation, and antiproliferative activities of two new triterpenoids along with eight known compounds [ABSTRACT FROM AUTHOR]

OBJECTIVES: This study aimed to investigate whether selective antegrade cerebral perfusion or retrograde cerebral perfusion is a better technique for brain protection in deep hypothermic circulatory arrest by obtaining metabolic evidence from microdialysis. DESIGN: Randomized, animal study. SETTING: Assisted circulation laboratory. SUBJECTS: Eighteen piglets of either sex (9.8 ± 3.1 kg). INTERVENTIONS: Animals were randomly assigned to 40 minutes of circulatory arrest at 18°C without cerebral perfusion (deep hypothermic circulatory arrest group, n = 6) or with selective antegrade cerebral perfusion (selective antegrade cerebral perfusion group, n = 6) or retrograde cerebral perfusion (retrograde cerebral perfusion group, n = 6). Reperfusion was continued for 3 hours. MEASUREMENTS AND MAIN RESULTS: Microdialysis (glucose, lactate, pyruvate, and glycerol) variables in the cortex dialysate were measured every 30 minutes. Intracerebral pressure and serum S-100 levels were also monitored. After 3 hours of reperfusion, cortical tissue was harvested for terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. After 40 minutes of circulatory arrest, the deep hypothermic circulatory arrest group presented marked elevations of intracerebral pressure, and serum S-100 levels were higher in the deep hypothermic circulatory arrest group than in the other two groups (p < 0.001, respectively). The selective antegrade cerebral perfusion group exhibited higher glucose, lower lactate, and lower glycerol levels and a lower lactate-to-pyruvate ratio in comparison to the deep hypothermic circulatory arrest group (p < 0.05, respectively); the retrograde cerebral perfusion group had lower lactate and glycerol levels and a lower lactate-to-pyruvate ratio (p < 0.05, respectively) but similar glucose levels compared to deep hypothermic circulatory arrest alone. Furthermore, selective antegrade cerebral perfusion provided better preservation of energy and cell integrity than retrograde cerebral perfusion with higher glucose and lower glycerol levels (p < 0.05, respectively). After 3 hours of reperfusion, fewer apoptotic neurons were found in selective antegrade cerebral perfusion animals than in the other two groups (p < 0.05, respectively). CONCLUSIONS: Both selective antegrade cerebral perfusion and retrograde cerebral perfusion were superior to deep hypothermic circulatory arrest alone during circulatory arrest. Retrograde cerebral perfusion was a moderate technique that had similar advantages with regard to less cerebral edema, better clearance of metabolic waste, and lower levels of biomarkers of injury than selective antegrade cerebral perfusion, but its capacity for energy preservation, maintenance of cellular integrity, and protection against apoptosis was lower than that of selective antegrade cerebral perfusion. [ABSTRACT FROM AUTHOR]

The reactivity of electron-donating substituted anilines with ethyl trifluoropyruvate is studied. [ABSTRACT FROM AUTHOR]

Background: The atrial fibrillation (AF) associated microRNAs (miRNAs) were found in the right atrium (RA) and left atrium (LA) from patients with rheumatic mitral valve disease (RMVD). However, most studies only focus on the RA; and the potential differences of AF-associated miRNAs between the RA and LA are still unknown. The aim of this study was to perform miRNA expression profiles analysis to compare the potential differences of AF-associated miRNAs in the right atrial appendages (RAA) and left atrial appendages (LAA) from RMVD patients.Methods: Samples tissues from the RAA and LAA were obtained from 18 RMVD patients (10 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Then, the results were validated using qRT-PCR analysis for 12 selected miRNAs. Finally, potential targets of 10 validated miRNAs were predicted and their functions and potential pathways were analyzed using the miRFocus database.Results: In RAA, 65 AF-associated miRNAs were found and significantly dysregulated (i.e. 28 miRNAs were up-regulated and 37 were down-regulated). In LAA, 42 AF-associated miRNAs were found and significantly dysregulated (i.e. 22 miRNAs were up-regulated and 20 were down-regulated). Among these AF-associated miRNAs, 23 of them were found in both RAA and LAA, 45 of them were found only in RAA, and 19 of them were found only in LAA. Finally, 10 AF-associated miRNAs validated by qRT-PCR were similarly distributed in RAA and LAA; 3 were found in both RAA and LAA, 5 were found only in RAA, and 2 were found only in LAA. Potential miRNA targets and molecular pathways were identified.Conclusions: We have found the different distributions of AF-associated miRNAs in the RAA and LAA from RMVD patients. This may reflect different miRNA mechanisms in AF between the RA and LA. These findings may provide new insights into the underlying mechanisms of AF in RMVD patients. [ABSTRACT FROM AUTHOR]

Background: MicroRNAs were enrolled in various cardiovascular disease especially ischemic heart diseases, but the microRNA changes during myocardial ischemia reperfusion injury underwent cardiopulmonary bypass are still unknown. This study screens the microRNA differences in CPB canines and evaluates the relationship of microRNAs with myocardial ischemia reperfusion injury.Methods: 13 healthy canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest, followed by 90 minutes reperfusion. Left ventricular myocardial samples, blood samples and hemodynamic data were taken at different time points. We performed microRNAs microarray experiments upon the left ventricle myocardium tissue of canines before CPB and after reperfusion for 90 minutes by pooling 3 tissue samples together and used qRT-PCR for confirmation.Results: Statistically significant difference was found in mir-499 level before CPB and after reperfusion (T1 vs. T4, p=0.041). We further examined the mir-499 levels by using qRT-PCR in all 13 canines at 4 different time points (T1 vs. T4, p=0.029). Mir-499 expression was negatively correlated with cardiac troponin T (cTnT) and creatine kinase- MB (CK-MB) levels of canines in all time points samples (r=0.469, p<0.001 and r=0.273, p=0.050 respectively). Moreover, higher mir-499 expression level was associated with higher dP/dtmax at 25 minutes and 90 minutes after reperfusion.Conclusion: Myocardial ischemic reperfusion injury with cardiopulmonary bypass results in declining level of mir-499 expression in left ventricle myocardium of canines, suggesting mir-499 would be a potential therapeutic target in cardiac protection during open heart surgery. [ABSTRACT FROM AUTHOR]

Based on a new semisynthetic route, a series of phosphotriester 7-alkyl-homocamptothecin derivatives are designed and synthesized. Cytotoxic activity assays show that compounds 12a and 14c with a methyl in position C7 of the homocamptothecin are more potent than the other derivatives and the positive drug irinotecan against A-549, MCF-7, and LOVO cell lines. Moreover, compound 14c shows potent tumour inhibitory activity in a Colo205 xenograft model. [ABSTRACT FROM AUTHOR]

We report a numerical simulation of continuous terahertz beam induced transient thermal effects on static water. The terahertz wave used in this paper has a Gaussian beam profile. Based on the transient heat conduction equation, the finite element method (FEM) is utilized to calculate the temperature distribution. The simulation results show the dynamic process of temperature change in water during terahertz irradiation. After about 300 s, the temperature reaches a steady state with a water layer thickness of 5 mm and a beam radius of 0.25 mm. The highest temperature increase is 7 K/mW approximately. This work motivates further study on the interaction between terahertz wave and bio-tissue, which has a high water content. [ABSTRACT FROM AUTHOR]

We report a widely tunable, narrow linewidth, pulsed Ti:sapphire laser pumped by an all-solid-state Q-switched intra-cavity frequency-doubled Nd:YAG laser. By using four dense flint glass prisms as intra-cavity dispersive elements, the output wavelength can be continuously tuned over 675-970 nm and the spectral linewidth is shortened to 0.5nm. The maximum output power of 6.65 W at 780nm is obtained under 23.4 W pump power with repetition rate of 5.5kHz; corresponding to an conversion efficiency of 28.4%. Due to the gain-switching characteristics of the Ti:sapphire laser, the output pulse duration is as short as 17.6 ns. [ABSTRACT FROM AUTHOR]

Dipolar and quadrupolar resonance wavelengths of SiO2/Au nanoshell surface plasmons are designed at 560 nm to enhance the light trapping in thin film solar cells. In order to quantitatively describe the light trapping effect, the forward-scattering efficiency (FSE) and the light trapping efficiency (LTE) are proposed by considering the light scattering direction of SiO2/Au nanoshells. Based on the Mie theory, the FSE and the LTE are calculated for SiO2/Au nanoshells of different dimensions, and the contributions of the dipolar and quadrupolar modes to the light trapping effect are analyzed in detail. When the surface coverage of nanoshells is 5%, the LTEs are 21.7% and 46.9% for SiO2/Au nanoshells with sizes of (31 nm, 69 nm) and (53 nm, 141 nm), respectively. The results indicate that the SiO2/Au nanoshell whose quadrupolar mode peak is designed to the strongest solar energy flux density of the solar spectrum facilitates the further enhancement of light harvesting in thin film solar cells. [ABSTRACT FROM AUTHOR]

Based on a Type II non-critically phase-matched KTA crystal, a low-threshold and high conversion efficiency mid-infrared optical parametric oscillator (OPO) pumped by a diode-end-pumped Nd:YVO4 laser is demonstrated. The OPO threshold is only 0.825 W. The maximum output power of 435mW at 3.47 mm is achieved with the repetition rate of 30 kHz, corresponding to an optical-to-optical conversion efficiency of 4.4%. The photon conversion efficiency is as high as about 64%. The pulse width is 3.5 ns with a peak power of 4kW for the maximum output power. [ABSTRACT FROM AUTHOR]

A cw diode side-pumped Nd:YAG laser is frequency doubled to 532nm with an intracavity KTP crystal in a V-shaped arrangement, achieving an output power of 40 W corresponding to an optical-optical conversion efficiency of 9.7%. The instabilities and the M2 -parameters of the laser are measured at different output powers after the beam is filtered. [ABSTRACT FROM AUTHOR]

Fe-doped CeO2 is synthesized by ceramic method and the effects of Fe doping on the structure and properties are characterized by ordinary methods and terahertz-time domain spectrometer (THz-TDS) technique. Our results show that pure CeO2 only has a small dielectric constant [?] of 4, while a small amount of Fe (0.9 at. %) doping into CeO2 promotes densification and induces a large e of 23. From the THz spectroscopy, it is found that for undoped CeO2 both the power absorption and the index of refraction increase with frequency, while for Fe-doped CeO2 we measure a remarkable transparency together with a flat index curve. The absorption coefficient of Fe-doped CeO2 at frequency ranging from 0.2 to 1.8 THz is less than 0.35 cm[?]1, implying that Fe-doped CeO2 is a potential THz optical material. [ABSTRACT FROM AUTHOR]