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Using two focused 1064 nm pump beams with an intensity ratio 3:1 and a small crossing angle θ ≈ 3.1 ∘ , two-photon pumped (2PP) tristable lasing behavior has been observed in a dye (AMSPT) solution in dimethyl sulfoxide (DMSO). When each pump beam is incident alone, the measured pump energy threshold for 2PP lasing is ∼ 3.8 m J . However, when the two pump beams are incident together, the energy of the strong pump beam varies from 4 to 10 mJ and the energy of the weak pump beam varies from 1.3 to 3.3 mJ. We then observe two simultaneous output lasing beams. However, when the strong pump beam is blocked, the weak pump beam is unable to create its own lasing output. This observed dual-beam lasing behavior can be well explained by a physical model of energy transfer between these two pump beams via the reflection of an induced Bragg grating. This observed dual-beam and tristable lasing behavior may be useful for future applications in an optical logical circuit or an optical computing system.

The spectral super-broadening of backward stimulated Raman scattering (SRS) in four liquid samples ( C C l 4 , dimethyl sulfoxide, acetone, and C H 2 C l 2 ) have been observed under the pump conditions of using 532-nm and ∼ 11 - n s pulsed laser beams from a frequency-doubled and multilongitudinal mode Pockels Q-switched Nd:YAG laser device. Under the same pump conditions, in acetone the observed maximum broadening range was ≥ 450 c m − 1 for the backward SRS, while it was ≤ 45 c m − 1 for the forward SRS. The physical origin of this observed effect is essentially related to the detailed temporal structure of the 532-nm pump pulse that consists of a series of subpulse of ∼ 50 p s width, owing to the randomly beating effect among a large number of longitudinal modes of the Pockels Q-switched laser source. Each backward SRS subpulse undergoes multiple cross-phase modulation (XPM) by interacting with a certain number of forward pump subpulses, and consequently manifests a super-broadened spectral distribution. In contrast, each forward SRS subpulse interacts only with a single pump subpulse and therefore experiences a much limited XPM influence, resulting in a much smaller spectral broadening. Furthermore, when the 532-nm pump beam was from a single-longitudinal mode-seeded Nd:YAG laser, there was no beating-effect-induced subpulse structure of the pump pulse, and thereby no noticeable spectral broadening for both backward and forward SRS could be observed.

A ferrocene labeled high molecular weight coenzyme derivative (PEI-Fc-NAD) was prepared by attaching both ferrocene (Fc) and coenzyme (nicotinamide adenine dinucleotide, NAD+) to the backbone of poly (ethylenimine) (PEI). A NAD-dependent glucose-6-phosphate dehydrogenase (G6PDH) was used with PEI-Fc-NAD to fabricate a multilayer film on gold electrode by layer-by-layer self-assembly method. The G6PDH/PEI-Fc-NAD multilayer film was characterized by atom force microscope and electrochemical experiment, which proved that a nanostructure thin film was immobilized by the LBL technique. The modified electrode showed the current response to glucose-6-phosphate in the absence of free coenzyme, and kept about 85% response after storage in buffer for 2 month.

An electrochemical phosphate sensor based on the precipitation of molybdophosphate on electrode surface was developed for the determination of inorganic phosphate. The condition for the formation of the molybdophosphate was studied and cyclic voltammetry and differential pulse voltammetry were utilized for the determination. A detection limit of 10 ppm was obtained and the sensor response was approximate liner in the range between 10-100 ppm.

Coenzyme, nicotinamide adenine dinucle-otide (NAD+) functionalized multi-walled carbon-nanotubes (MWCNTs) were prepared in this work. Carboxylic groups were firstly introduced to MWCNTs by oxidation in a mixture of sulfuric acid and nitric acid, and the NAD moistures were further attached by the formation of amide bonds with carboxylic groups under the help of 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimidehydrochloride and N-hydroxysuccinimide, which resulted in the coenzyme functionalized materials, MWCNTs-NAD. The MWCNTs-NAD was characterized by UV-Vis, FT-IR and TEM, and it was found clearly that the MWCNTs-NAD exhibited coenzyme activity compared with native NAD+ in reaction catalyzed by NAD-dependent alcohol dehydrogenase. The application of MWCNTs-NAD on the construction of dehydrogenase biosensor was further investigated.

To solve the difficulties in machining toric spectacle lens, the turning method with slow tool servo was discussed. First, the experimental setup was developed, which have X-axis, Z-axis and C-axis, and the movement of the three axes can be simultaneously controlled by numerical control system. Then, the mathematical model of toric was established, and its machining model was analyzed and simulated. Finally, the machining experiments were carried in the experimental setup. The experiments showed that the turning method based on slow tool servo can meet the requirements for machining the toric spectacle lens.

A high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of curcumin and its prodrug, curcumin didecanoate (CurDD), in rat plasma. The analytes were extracted by ethyl acetate following the addition of sodium dodecyl sulfate, and separated on a reverse-phase C(18) column using a gradient mobile phase system of acetonitrile-tetrahydrofuran-water containing 0.1% formic acid. Detection by UV absorption at 425 nm gave a lower limit of quantitation (LLOQ) of 5 and 10 ng/mL for curcumin and CurDD in 50 μL of plasma, respectively. Intra- and inter-day precisions of quality control samples except those at LLOQ were within 15% for curcumin and CurDD, respectively, and the accuracies for both compounds were between 93.9 and 108%. The method was successfully applied to determine plasma concentration-time curves of curcumin and CurDD in rats following intravenous (i.v.) administration of curcumin or CurDD at doses of 1 mg/kg (calculated as curcumin). The results suggested that i.v. dosed CurDD provided sustained plasma levels of curcumin.

Although the effect of a magnetic field on functions of many proteins has been reported, tubulin assembly in a hypogeomagnetic field (HGMF) has not yet been characterized. Here, we show disorder in tubulin self-assembly in an HGMF. Absorbance at 350 nm, commonly used to monitor tubulin self-assembly, was altered in the HGMF, providing evidence for the effects of HGMF on tubulin. Measurements of intrinsic fluorescence (335 nm) also revealed a disordered change in tubulin conformation during assembly in the HGMF. Under the same conditions, microtubule-like filaments were not observed by electron microscopy, with the exception of amorphous oligomers. Incubation of tubulin with tau in the natural geomagnetic field (GMF) yielded microtubule-like filaments, while only amorphous oligomers were observed following the incubation in the HGMF. This distinction suggests that tubulin assembly depends upon the GMF, and that elimination of the GMF induces disorder in tubulin organization.

Neuronal tau, through its proline-rich domain and the microtubule binding domain, binds to RNA non-sequence-specifically via electrostatic interaction. This binding inhibits the activity of tau. Tau and RNA were also found to co-localize in SH-SY5Y cells suggesting that RNA has opportunities to interact with tau in cells.

To explore methods and therapeutic effects of transpedicular bone graft in treating thoracolumbar fractures through Wiltse approach.From March 2009 to February 2012,56 patients with thoracolumbar fractures were treated by transpedicular bone graft through Wiltse approach. Among them, there were 36 males and 20 females, ranging in age from 14 to 55 years old (mean, 41 years old). The time from injury to operation from 2 to 15 d (mean,3 d). Twenty-five cases were caused by falling down, 7 cases were caused by slipping, 20 cases were caused by car accident and 4 cases were caused by crush trauma. MRI was performed before operation to exclude pathological fracture. The distance between multifidus muscle and longissimus to midcourt line was measured. Self-made trocar was applied in operation. According to AO classification,there were 33 cases with type A1 compression fracture,5 cases with type A2 cleavage fracture and 18 cases with type A3 burst fracture. Sixteen cases of the 56 cases combined with spinal cord injury. Based on Frankel neurologic grading system, preoperative neurological function was grade B in 5 cases, grade C in 2 cases, gade D in 9 cases. Preoperative Denis gading were P5. Frankel and lumbago Denis clssification were used to evaluate neurological function and lumbago. The imaging data before, after operation and the latest follow-up were used to evaluate correction vision.All patients were followed up over 24 months. At the time of the latest follow-up, Frankel B were 3 cases, Frankel C were 2 cases, Frankel D were 4 cases and Frankel E were 7 cases. According to lumbago Denis clssification, P1 (painlessness) were 32 cases, P2 ( slight pain without treatment) were 18 cases, P3 ( moderate pain and taking medicine occasionally) were 6 cases. The anterior vertebral height improved from preoperative (13.38 +/- 4.72)mm to postoperative (22.18 +/- 1.44)mm. The Cobb's angle decreased from preoperative (28.39 +/- 2.64) degrees to (10.07 +/- 3.05) degrees. There were no nails broken, rod broken, internal fixation lossen and vertebral body recompression.Transpedicular bone graft for thoracolumbar fractures through Wiltse approach can reduce intraoperative blood loss and postoperative complications, and aviod "eggshell" vertebral body. Mastering revealed way, drafting detailed preoperative plan and eariler exercise is the key to the success of treatment.

Tau, an important microtubule associated protein, has been found to bind to DNA, and to be localized in the nuclei of both neurons and some non-neuronal cells. Here, using electrophoretic mobility shifting assay (EMSA) in the presence of DNA with different chain-lengths, we observed that tau protein favored binding to a 13 bp or a longer polynucleotide. The results from atomic force microscopy also showed that tau protein preferred a 13 bp polynucleotide to a 12 bp or shorter polynucleotide. In a competitive assay, a minor groove binder distamycin A was able to replace the bound tau from the DNA double helix, indicating that tau protein binds to the minor groove. Tau protein was able to protect the double-strand from digestion in the presence of DNase I that was bound to the minor groove. On the other hand, a major groove binder methyl green as a negative competitor exhibited little effect on the retardation of tau-DNA complex in EMSA. This further indicates the DNA minor groove as the binding site for tau protein. EMSA with truncated tau proteins showed that both the proline-rich domain (PRD) and the microtubule-binding domain (MTBD) contributed to the interaction with DNA; that is to say, both PRD and MTBD bound to the minor groove of DNA and bent the double-strand, as observed by electron microscopy. To investigate whether tau protein is able to prevent DNA from the impairment by hydroxyl free radical, the chemiluminescence emitted by the phen-Cu/H(2)O(2)/ascorbate was measured. The emission intensity of the luminescence was markedly decreased when tau protein was present, suggesting a significant protection of DNA from the damage in the presence of hydroxyl free radical.

Background The microtubule associated protein tau is the principle component of neurofibrillar tangles, which are a characteristic marker in the pathology of Alzheimer's disease; similar lesions are also observed after chronic alcohol abuse. Formaldehyde is a common environmental contaminant and also a metabolite of methanol. Although many studies have been done on methanol and formaldehyde intoxication, none of these address the contribution of protein misfolding to the pathological mechanism, in particular the effect of formaldehyde on protein conformation and polymerization. Results We found that unlike the typical globular protein BSA, the natively-unfolded structure of human neuronal tau was induced to misfold and aggregate in the presence of ~0.01% formaldehyde, leading to formation of amyloid-like deposits that appeared as densely staining granules by electron microscopy and atomic force microscopy, and bound the amyloid-specific dyes thioflavin T and Congo Red. The amyloid-like aggregates of tau were found to induce apoptosis in the neurotypic cell line SH-SY5Y and in rat hippocampal cells, as observed by Hoechst 33258 staining, assay of caspase-3 activity, and flow cytometry using Annexin V and Propidium Iodide staining. Further experiments showed that Congo Red specifically attenuated the caspase-3 activity induced by amyloid-like deposits of tau. Conclusion The results suggest that low concentrations of formaldehyde can induce human tau protein to form neurotoxic aggregates, which could play a role in the induction of tauopathies.