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We develop a numerical scheme for solving the one-dimensional (1D) time-dependent Schrödinger equation (TDSE), and use it to study the strong-field photoionization of the atomic hydrogen. The photoelectron energy spectra obtained for pulses ranging from XUV to near infrared are compared in detail to the spectra calculated with our well-developed code for accurately solving the three-dimensional (3D) TDSE. For XUV pulses, our discussions cover intensities at which the ionization is in the perturbative and nonperturbative regimes. For pulses of 400 nm or longer wavelengths, we distinguish the multiphoton and tunneling regimes. Similarities and discrepancies between the 1D and 3D calculations in each regime are discussed. The observed discrepancies mainly originate from the differences in the transition matrix elements and the energy level structures created in the 1D and 3D calculations. [ABSTRACT FROM AUTHOR]

In this paper, 2024 Al alloy and AZ31B Mg alloy were brazed with aid of stirring without flux in air. The effects of the brazing temperature on microstructure and shear strength of the joint were investigated. The diffusion zone is found at joint interface near Al base metal, which consists of Al-Zn-Sn solid solution. At the same time, continuous intermetallic compounds (IMCs) phase and broken ones are found at joint interface near Mg base metal, which mainly consists of the MgSn phase. With the increase of the brazing temperature, the shear strength at the joint interface near Al base metal rises gradually. On the contrary, that of the joint interface near Mg base metal obviously decreases. [ABSTRACT FROM AUTHOR]

AZ31B magnesium alloy and 2024 aluminum alloy were successfully jointed at aid of mechanical stirring with Sn–Zn–Al filler metal. The microstructure, fracture morphologies, and mechanical properties of joint were investigated. The results show that Mg–Al intermetallic compounds can be avoided by the process. But, a small quantity of porosity is found in the joint. The shearing strength of joint interface adjacent to magnesium alloy is 35.4 MPa for formation of Mg–Sn intermetallic compounds, which is about 46 % of that of filler metal. While, the shearing strength of joint interfaces adjacent to aluminum alloy is 70.4 MPa for formation of Zn–Sn–Al solid solution, which is about 92 % of that of filler metal. [ABSTRACT FROM AUTHOR]

Biothiols, such as cysteine (Cys) and homocysteine (Hcy), play very crucial roles in biological systems. Abnormal levels of these biothiols are often associated with many types of diseases. Therefore, the detection of Cys (or Hcy) is of great importance. In this work, we have synthesized an excellent 'OFF-ON' phosphorescent chemodosimeter 1 for sensing Cys and Hcy with high selectivity and naked-eye detection based on an IrIII complex containing a 2,4-dinitrobenzenesulfonyl (DNBS) group within its ligand. The 'OFF-ON' phosphorescent response can be assigned to the electron-transfer process from IrIII center and C^N ligands to the DNBS group as the strong electron-acceptor, which can quench the phosphorescence of probe 1 completely. The DNBS group can be cleaved by thiols of Cys or Hcy, and both the 3 MLCT and 3LC states are responsible for the excited-state properties of the reaction product of probe 1 and Cys (or Hcy). Thus, the phosphorescence is switched on. Based on these results, a general principle for designing 'OFF-ON' phosphorescent chemodosimeters based on heavy-metal complexes has been provided. Importantly, utilizing the long emission-lifetime of phosphorescence signal, the time-resolved luminescent assay of 1 in sensing Cys was realized successfully, which can eliminate the interference from the short-lived background fluorescence and improve the signal-to-noise ratio. As far as we know, this is the first report about the time-resolved luminescent detection of biothiols. Finally, probe 1 has been used successfully for bioimaging the changes of Cys/Hcy concentration in living cells. [ABSTRACT FROM AUTHOR]

An excellent red-emissive BODIPY dye containing a benzo[2,1,3]thiadiazole bridge was synthesized, and its sensing ability toward metal cations was investigated in detail. It can work as a highly selective probe for Hg2+detected by the naked eye, with evident solution color and photoluminescence changes. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs) are known to play a critical role in tissue disintegration, and an elevated level of MMPs is observed in synovium and synovial fluid of joints with rheumatoid arthritis. During joint movement, synovial tissue receives various mechanical stimuli, but effects of mechanical challenges on regulation of MMPs in rheumatic synovium are poorly understood. Focusing on cellular responses to oscillatory fluid shear in human synovial cells, we determined the expression of MMP-1 and MMP-13 by polymerase chain reaction and immunoblotting as well as proteolytic activities of total MMPs by a fibril degradation assay and zymography. The results revealed that ∼0.5 dyn/cm 2 oscillatory shear at 1 Hz not only reduced an mRNA level and a protein level of MMP-1 and MMP-13, but it also decreased collagenase and gelatinase activities of total MMPs. Furthermore, the induction of the MMP expression and activities by interleukin-1 was suppressed by the oscillatory shear. Interestingly, the oscillatory shear upregulated the mRNA expression of TIMP-1 and TIMP-2. Our results support a potential role of oscillatory shear in regulating expression and activities of MMPs in the presence and the absence of proinflammatory cytokine. [ABSTRACT FROM AUTHOR]

Presents information on a study which focused on identification of cytokine-inducible gene, related to melanocyte-specific gene, through mRNA differential display of interleukin. Materials and methodology; Results; Discussion on the results.

PURPOSE: To observe the effect of three protective agents on edge closeness of glass ionomer cements filling in vitro. METHODS: Eighty- freshly extracted human molars were randomly divided into A and B groups(40 molars each group). The teeth cavities were prepared at 1/3 part to buccal gingiva of each molar and those of A group were filled with GC Fuji IX and those of B group with another glass ionomer cement. A and B groups were respectively divided into three experiment groups and one control group(A1/B1). The filling surfaces of three experimental groups were separately coated with vaseline (A2/B2), cocoa butter (A3/B3), biscover (A4/B4). After thermal cycling (x30, 5 -55°C), the depth of dye penetrating into the teeth was observed through an optical microscope. The data was analyzed with rating information on diverse groups of the rank and testing, using SPSS13.0 software package. RESULTS: Different dye penetration degrees were shown between filling material and cavity walls among each group, while the degrees of dye penetration of experimental groups were significantly slighter than those of corresponding control group (P<0.05), and there was no difference among experimental groups (P>0.05). CONCLUSION: The three protective agents can increase the edge closeness of glass ionomer cement filling. [ABSTRACT FROM AUTHOR]

Background: Moderate loads with knee loading enhance bone formation, but its effects on the maintenance of the knee are not well understood. In this study, we examined the effects of knee loading on the activity of matrix metalloproteinase13 (MMP13) and evaluated the role of p38 MAPK and Rac1 GTPase in the regulation of MMP13.Methods: Knee loading (0.5-3 N for 5 min) was applied to the right knee of surgically-induced osteoarthritis (OA) mice as well as normal (non-OA) mice, and MMP13 activity in the femoral cartilage was examined. The sham-loaded knee was used as a non-loading control. We also employed primary non-OA and OA human chondrocytes as well as C28/I2 chondrocyte cells, and examined MMP13 activity and molecular signaling in response to shear at 2-20 dyn/cm².Results: Daily knee loading at 1 N for 2 weeks suppressed cartilage destruction in the knee of OA mice. Induction of OA elevated MMP13 activity and knee loading at 1 N suppressed this elevation. MMP13 activity was also increased in primary OA chondrocytes, and this increase was attenuated by applying shear at 10 dyn/cm². Load-driven reduction in MMP13 was associated with a decrease in the phosphorylation level of p38 MAPK (p-p38) and NFκB (p-NFκB). Molecular imaging using a fluorescence resonance energy transfer (FRET) technique showed that Rac1 activity was reduced by shear at 10 dyn/cm² and elevated by it at 20 dyn/cm². Silencing Rac1 GTPase significantly reduced MMP13 expression and p-p38 but not p-NFκB. Transfection of a constitutively active Rac1 GTPase mutant increased MMP13 activity, while a dominant negative mutant decreased it.Conclusions: Knee loading reduces MMP13 activity at least in part through Rac1-mediated p38 MAPK signaling. This study suggests the possibility of knee loading as a therapy not only for strengthening bone but also preventing tissue degradation of the femoral cartilage. [ABSTRACT FROM AUTHOR]