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OBJECTIVE: To evaluate the protective effect of dexmedetomidine (Dex) against renal ischemia-reperfusion injury (RIRI) in rats through the phosphatidylinositol 3-hydroxy kinase (PI3K)/protein kinase B (Akt)/hypoxia-inducible factor-1α (HIF-1α) signaling pathway. MATERIALS AND METHODS: (1) A Sprague-Dawley rat model of RIRI was established. Thirty rats were divided into Sham group, injury (RIRI) group, and Dex treatment (RIRI + Dex) group. Serum was collected to detect renal function-related indexes, and the levels of serum inflammatory factors were examined via enzyme-linked immunosorbent assay (ELISA). (2) The kidney tissues were separated, and the degree of tissue damage was determined using immunohistochemical staining. (3) Ribonucleic acids (RNAs) were extracted from tissues, and the mRNA levels of inflammatory factors were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). (4) The protein expressions of Akt, phosphorylated (p)-Akt, PI3K, p-PI3K, and HIF-1α were detected via Western blotting. RESULTS: Compared with those in RIRI group, the levels of blood urea nitrogen and creatinine declined (p<0.05), the synthesized mRNAs of inflammatory factors in the kidney tissues were reduced (p<0.05), the secreted serum inflammatory factors was also reduced (p<0.05), and the phosphorylation levels of Akt and PI3K and the HIF-1α level rose (p<0.05) in RIRI + Dex group. CONCLUSIONS: Dex promotes the recovery of renal function and reduces the inflammatory level in RIRI rats through the PI3K/Akt/HIF-1α signaling pathway. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of this study was to explore the association between the expression of mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) pathway and neuronal apoptosis in rats with white matter lesions (WML). MATERIALS AND METHODS: Sprague-Dawley (SD) rats were selected as the research objects. Rat models of ischemic WML were established by bilateral common carotid artery ligation. Subsequently, brain tissues were collected from rats in sham operation group and WML group, respectively. Hematoxylin-eosin (HE) staining assay was conducted to observe the pathological changes in white matters (WMs) (callosum, internal capsule, and optic nerve) and apoptotic cells in brain tissues. The protein expression levels of phosphorylated ERK (p-ERK) and ERK, phosphorylated MAPK (p-MAPK), and MAPK in tissues were measured by Western blotting. Immunohistochemistry was employed to detect the expression levels of p-ERK, ERK, p-MAPK, and MAPK in brain tissues of the two groups. Next, nerve cells were isolated from rats with WML as research objects. The phosphorylation of the MAPK/ERK pathway was suppressed using PD03259019 (a chemical drug, hereafter referred to as PD). Then, the changes in the protein expressions of apoptosis proteins B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were determined before and after MAPK/ERK pathway inhibition. Meanwhile, changes in the messenger ribonucleic acid (mRNA) expression levels were detected via real-time fluorescent quantitative polymerase chain reaction (PCR), and changes in apoptosis were observed. RESULTS: HE staining revealed that in sham operation group, WMs had normal structure and intact morphology. The cells were regularly arranged, with little apoptosis of the nuclei in the center. However, there were abnormally arranged nerve cells, loose cortical structure, swollen cells, aberrant nuclear membrane, pyknosis, signs of cell degeneration and necrosis, apoptotic cells filled most of the field of vision, and relatively evident lesions in WML group. Besides, WML group exhibited significantly up-regulated expressions of p-ERK and p-MAPK, as well as basically unchanged expressions of ERK and MAPK (p<0.05). After PD was added for 1 d, 2 d, and 3 d, the MAPK/ERK pathway was repressed, which was the most significantly at 3 d. Furthermore, the anti-apoptotic phenotype of neurons was detected, which was more pronounced at 3 d (p<0.05). CONCLUSIONS: Rats with WML exhibited elevated MAPK/ERK activity and evident apoptosis. After inhibiting the phosphorylation site of MAPK/ERK in rat neuronal cells, the expression of pro-apoptotic protein decreased, and the apoptosis was relieved. In rats with WML, neuronal apoptosis is promoted by activating the MAPK/ERK pathway, thus worsening the condition. [ABSTRACT FROM AUTHOR]

Optical quality Sr[sub x]Ba[sub 1-x]Nb[sub 2]O[sub 6] (SBN) thin films, both undoped and Eu[sup 3+]-doped, of thickness less than 0.5 μm have been successfully grown on fused quartz substrates using a pulsed laser deposition technique. Optical properties of these films were characterized in high-resolution spectroscopic experiments in time and frequency domains. For undoped SBN thin films, broadband emission in the UV region extending to the visible was observed following excitation at 355 nm. This emission is attributed to exciton luminescence of the SBN film. Nonlinear optical response in the picosecond regime and the third-order nonlinear susceptibility, χ[sup (3)], were studied using degenerate four-wave-mixing methods. In transverse alignment, χ[sup (3)] is enhanced by two orders of magnitude in comparison with its bulk counterpart. A thermal annealing process, monitored via changes in spectral properties of Eu[sup 3+], was employed to convert the as-grown amorphous film into a polycrystalline film. High-resolution spectroscopic measurements in the frequency domain were conducted on a 200-nm-thick film of Eu[sup 3+]-doped SBN. Our spectroscopic results suggest that Eu[sup 3+] ions may substitute for Nb, thereby occupying a normally six-fold coordinated lattice site. At liquid helium temperature, spectral holes in the [sup 7]F[sub 0]–[sup 5]D[sub 0] optical transition were burned in the thermally annealed films. Typical observed hole widths were 70–100 MHz and hole depths were as large as 30% of the peak fluorescence intensity. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report a systematic analysis of the crystal-field spectra of four fluoride compounds containing tetravalent actinide ions. The first part of this work [J. Chem. Phys. 95, 7194 (1991)] provided interpretation of the absorption spectra of UF4, NpF4, and PuF4. To extend our analysis to heavier elements of the series, low-temperature absorption spectra of AmF4 and CmF4, and site selective laser-induced emission and excitation spectra of Cm4+:CeF4 and Bk4+:CeF4 were obtained. A model energy level calculation was found to be in good agreement with the experimental results. It is shown that the crystal-field interaction in combination with spin–orbital coupling results in significant J mixing in the excited states, but ground state wave functions are still relatively pure in J character for the tetravalent actinide ions Am4+, Cm4+, and Bk4+. Trends in the parameters of the effective operator Hamiltonian are compared with those of a Hartree–Fock free-ion model. Interpretation of the ground-state splitting of the nominal S-state ion Bk4+ in CeF4 and color center formation in AmF4 are also discussed. [ABSTRACT FROM AUTHOR]

We report optical-spectroscopic studies of the ground-state splitting of the nominal S-state ion Cm3+ in LaCl3. A total splitting of 1.97±0.05 cm-1 for the 8S7/2 ground state of this system has been measured for the first time. Both electric and magnetic dipole transitions were observed. Energy levels of all four Kramers doublets of the 8S7/2 manifold were resolved by means of the site-selective excitation and emission spectra of 8S7/26D7/2 and 8S7/26P5/2 transitions. Our results show that the lowest component of the ground manifold is a μ=5/2 state dominated by M=|±7/2> in contrast to a previously reported μ=1/2 state. The crystal-field model, established through analyzing optical spectra of the excited states, predicts a ground-state splitting with the right ordering but greater magnitude. In comparison with the lanthanide S-state ion Gd3+, much stronger spin–orbit coupling and reduced electrostatic interaction in concert with greater crystal field interaction significantly influence the characteristics of the ground state of the actinide S-state ion. Contributions from within the 5f7 configuration account for most of the observed splitting. [ABSTRACT FROM AUTHOR]

An interpretation of the low-temperature absorption spectra of AnF4 (An=U, Np, Pu) is presented. Using an effective operator Hamiltonian with orthogonalized free-ion operators and initializing crystal-field parameter values based on a superposition model calculation for An4+ sites with C2 symmetry, good agreement between the model calculations and experimentally observed absorption band structure could be obtained. Correlations with published magnetic and heat capacity measurements are discussed. [ABSTRACT FROM AUTHOR]

Presents a study which focused on Raman heterodyne detection of magnetic resonance in a phosphate glass. Methods; Results; Discussion.

Deals with a study which examined the laser-excitation and emission spectra of TbPO[sub4] and 0.1% Tb-doped YPO4 single crystals. Experimental details; Results and discussion; Neutron-scattering measurements.

Surveys conducted in peanut production areas of China revealed peanut pod rot in several fields in Shandong and Hebei Provinces, China. A large quantity of an unknown stem nematode was isolated from the hulls and seeds of peanuts, herein described as Ditylenchus arachis n. sp. The new species is characterized by a combination of the following features: lateral lip sectors distinctly projected, stylet delicate, 8·4-10 µm in length, six lines in the lateral field, tail elongate-conoid, bursa covering about 68-86% of tail length. Pathogenicity tests showed that D. arachis n. sp. could infect peanut (Arachis hypogaea), but not sweet potato (Ipomoea batatas) or potato (Solanum tuberosum). Morphologically, D. arachis n. sp. appears closest to D. africanus, D. myceliophagus and D. destructor, but can be differentiated based upon a combination of morphological characteristics, host preference and molecular sequence data. The results of the phylogenetic analysis, based on 18S rDNA, the D2-D3 expansion region of 28S rDNA, and the ITS1-5·8S-ITS2 region, confirmed its status as a new species. A sister relationship with D. destructor was appointed, rather than with its ecologically very similar congener D. africanus. [ABSTRACT FROM AUTHOR]