Unveiling the mechanism for selective cleavage of C-C bonds in sugar reactions on tungsten trioxide-based catalysts.

Conversion of naturally occurring sugars, the most abundant biomass resources on Earth, to fuels and chemicals provides a sustainable and carbon-neutral alternative to the current fossil resource-based processes. Tungsten-based catalysts (e.g., WO3) are efficient for selectively cleaving C-C bonds of sugars to C2,3 oxygenate intermediates (e.g., glycolaldehyde) that can serve as platform molecules with high viability and versatility in the synthesis of various chemicals. Such C-C bond cleavage follows a mechanism distinct from the classical retro-aldol condensation. Kinetic, isotope 13C-labeling, and spectroscopic studies and theoretical calculations, reveal that the reaction proceeds via a surface tridentate complex as the critical intermediate on WO3, formed by chelating both α- and ß-hydroxyls of sugars, together with the carbonyl group, with two adjacent tungsten atoms (W-O-W) contributing to the ß-C-C bond cleavage. This mechanism provides insights into sugar chemistry and enables the rational design of catalytic sites and reaction pathways toward the efficient utilization of sugar-based feedstocks.

Evaluation of potential radiological hazards of unfired construction materials containing fly ash in Vietnam.

In this study, the specific activities of 226Ra, 232Th and 40K in the unfired construction materials (solid card bricks, 4-hole bricks, pavement bricks) containing fly ash and bottom ash from a coal-fired thermal power plant in Vietnam were measured using the low-level gamma-ray spectrometer with HPGe detector. Also, the 222Rn concentrations in these materials were analyzed using RAD7 radon monitor and then radon mass exhalation rate and emanation fraction of these materials were calculated. The potential radiological hazards for residents living in the model room made of these materials were evaluated. The average specific activity of 226Ra, 232Th and 40K were found as 67.7, 79.3 and 703.5 Bq kg-1, respectively. The total annual effective dose (due to external gamma exposure and internal radon exposure for resident living in the CEN model room made of the unfired brick samples) was found as 0.9 mSv y-1 which is lower than the worldwide average dose of 2.4 mSv y-1. Calculations from ResRad-Build code showed that the doses due to radon exposure account for from 62.3% (at the first year) to 98.8% (at the next 30 years) of the total gamma and radon dose. Under low air exchange to the outside environment, from the 6th year onwards, the total dose may exceed the average dose value from natural radiation exposure sources.

CuCl-photocatalyzed C-H amination of benzoxazoles.

The direct coupling of benzoxazoles and amines was realized by visible light irradiation and CuCl catalysis. Various aminated benzoxazoles were successfully synthesized under mild conditions with air as an oxidant.

Metal-Free Photosynthesis of Alkylated Benzimidazo[2,1-a]isoquinoline-6(5H)-ones and Indolo[2,1-a]isoquinolin-6(5H)-ones in PEG-200.

A visible-light-induced decarboxylation reaction was developed for the synthesis of alkylated benzimidazo[2,1-a]isoquinoline-6(5H)-ones and indolo[2,1-a]isoquinolin-6(5H)-ones under metal-free conditions. Impressively, metal catalysts and traditionally volatile organic solvents could be effectively avoided.

Cytocompatibility of Ti-xZr alloys as dental implant materials.

Ti-xZr (x = 5, 15, 25, 35, 45% wt%) alloys with low elastic modulus and high mechanical strength were fabricated as a novel implant material. The biocompatibility of the Ti-xZr alloys was evaluated by osteoblast-like cell line (MG63) in terms of cytotoxicity, proliferation, adhesion, and osteogenic induction using CCK-8 and live/dead cell assays, electron microscopy, and real-time PCR. The Ti-xZr alloys were non-toxic and showed superior biomechanics compared to commercially pure titanium (cpTi). Ti-45Zr had the optimum strength/elastic modulus ratio and osteogenic activity, thus is a promising to used as dental implants.

Effect of Evodiamine on CYP Enzymes in Rats by a Cocktail Method.

The aim of this study was to assess the influence of evodiamine on the activities of the drug-metabolizing enzymes cytochrome P450 (CYP) 1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 in rats. The activities of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 were measured using specific probe drugs. After pretreatment for 1 week with evodiamine or physiological saline (control group) by oral administration, probe drugs phenacetin (5.0 mg/kg; CYP1A2 activity), tolbutamide (1.0 mg/kg; CYP2C9 activity), omeprazole (10 mg/kg; CYP2C19 activity), metoprolol (20 mg/kg; CYP2D6 activity) and midazolam (10 mg/kg; CYP3A4 activity) were administered to rats by oral administration. The blood was then collected at different times for ultra-performance liquid chromatography-tandem mass spectrometry analysis. The data showed that evodiamine exhibits an inhibitory effect on CYP1A2, CYP2C9 and CYP2D6 by increasing t(1/2), Cmax and AUC(0-∞), and decreasing CL/F compared with those of the control group. However, no significant changes in CYP2C19 and CYP3A4 activities were observed. In conclusion, the results indicated that evodiamine could inhibit CYP1A2, CYP2C9 and CYP2D6, which may affect the disposition of medicines primarily dependent on these pathways. Our work may be the basis of related herb-drug interactions in the clinic.

Surface plasmon resonance sensor based on polymer photonic crystal fibers with metal nanolayers.

A large-mode-area polymer photonic crystal fiber made of polymethyl methacrylate with the cladding having only one layer of air holes near the edge of the fiber is designed and proposed to be used in surface plasmon resonance sensors. In such sensor, a nanoscale metal film and analyte can be deposited on the outer side of the fiber instead of coating or filling in the holes of the conventional PCF, which make the real time detection with high sensitivity easily to realize. Moreover, it is relatively stable to changes of the amount and the diameter of air holes, which is very beneficial for sensor fabrication and sensing applications. Numerical simulation results show that under the conditions of the similar spectral and intensity sensitivity of 8.3 × 10(-5)-9.4 × 10(-5) RIU, the confinement loss can be increased dramatically.

Visible-Light-Promoted Intermolecular ß-Acyl Difunctionalization of Alkenes via Oxidative Radical-Polar Crossover.

A visible-light-induced ß-acyl difunctionalization of alkenes with acyl oxime esters and various nucleophiles was developed to achieve molecular complexity from readily available raw materials via oxidative radical-polar crossover. A variety of nucleophiles, including NH-sulfoximines, indoles, indazole, and trimethoxybenzene, were all effectively applicable to the sustainable reaction system. The novel synthetic strategy features mild reaction conditions, a broad substrate scope (39 examples), easy scale-up, and excellent regioselectivity.

Insights into the volatile flavor and quality profiles of loquat (Eriobotrya japonica Lindl.) during shelf-life via HS-GC-IMS, E-nose, and E-tongue.

Loquat fruits are among the most popular Chinese fruits because of their unique taste and aroma. The quality profiles of these fruits during 18 days of shelf-life at 20 °C were elucidated by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), E-nose, and E-tongue. During shelf-life period, the properties and variations of 43 (20 aldehydes, 7 esters, 6 ketones, 1 alcohol, and 1 furan) volatile flavored compounds were determined by GC-IMS, which showed that the contents of methyl 3-methyl butanoate, ethyl acetate, and dimethyl ketone gradually decrease with prolonged shelf-life time, while (E)-2-heptenal, heptanal, (E)-2-pentenal, 1-penten-3-one 3-pentanone and 2-pentylfuran increase. The PCA based on the signal intensity of GC-IMS and E-nose, revealed that loquat fruits are well distinguished at different shelf-life times. The taste profile alternates as the storage time increases, along with higher pH, and lower amounts of total soluble solids, vitamin C, and total phenolics. The visual plots of GC-IMS, E-nose, and E-tongue had good consistency, and they characterized the aroma characteristics of loquat fruits well during different shelf-life periods. The findings of this research provide a useful understanding of the flavors of loquat fruits during their prolonged shelf-life, and a potential research basis for advancements in the loquat industry.

Grapefruit fiber filled with silver nanowires surface plasmon resonance sensor in aqueous environments.

A kind of surface plasmon resonance sensor based on grapefruit photonic crystal fiber (PCF) filled with different numbers of silver nanowires has been studied in this paper. The surface plasmon resonance modes and the sensing properties are investigated comprehensively using the finite element method (FEM). The simulation results show that the intensity sensitivity is related to nanowire numbers and the distance between two nanowires. The optimum value obtained is 2,400 nm/RIU, corresponding to a resolution of 4.51 × 10(-5) RIU with a maximum distance of 2 µm. To a certain extent, the PCF filled with more nanowires is better than with just one. Furthermore, the air holes of grapefruit PCF are large enough to operate in practice. Moreover, the irregularity of the filled nanowires has no effect on sensitivity, which will be very convenient for the implementation of experiments.

Ce(III)/Photoassisted Synthesis of Amides from Carboxylic Acids and Isocyanates.

The Ce(III)-photocatalyzed synthesis of amides from carboxylic acids and aryl isocyanates was developed. The reaction includes the formation of alkyl radicals from carboxylic acids followed by radical addition to the electron-deficient carbon of isocyanate.

Naphthalimide-based a highly selective two-photon fluorescent probe for imaging of hydrogen sulfide in living cells and inflamed tissue of mouse model.

Hydrogen sulfide (H2S) is a very important third endogenously generated gaseous signaling molecule and plays a key role in physiological and pathological regulation processes of living biosystems. Although a lot of H2S fluorescent probes have been reported, the relationship between the physiology and pathology of H2S in inflamed tissues remains unclear. Herein, by adopting a donor-π-acceptor (D-π-A)-structured naphthalimide derivative as the two-photon (TP) fluorophore and a 4-dinitrobenzene-ether (DNB) with a strong intramolecular charge transfer (ICT) effect as the recognition moiety, we reported a novel TP bioimaging probe NP-H2S for H2S with improved sensitivity. The NP-H2S exhibits very low background fluorescence in the absence of H2S, and a significant 258-fold fluorescence intensity enhancement was observed in the presence of H2S, resulting in a high sensitivity and selectivity to H2S in aqueous solutions with a detection limit of 18.8 nM observed. The probe also shows a wide linear response concentration range (0-10.0 µM) to H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in tissues of inflammation model with satisfactory sensitivity, indicating it has the latent capability in further biological applications for investigation of the interaction H2S with inflammation.

Cytocompatibility, stability and osteogenic activity of powder metallurgy Ta-xZr alloys as dental implant materials.

Tantalum (Ta) and zirconium (Zr) alloys were found to had low elastic modulus and similar biomechanical characteristics as the human bone. However, the biocompatibility and osteogenic potential of Ta-xZr alloyswith different proportions (20, 30, 40 and 50% Zr by atom) remains to be investigated. In this study, the biocompatibility of Ta-xZr alloys and commercially pure titanium (cpTi) was evaluated in vitro by cell counting kit-8 assay. The adhesion of MG63 osteoblasts to the surface of the alloys was observed by fluorescence microscopy, and their morphology was analyzed by scanning electron microscopy (SEM). The expressions of alkaline phosphatase (ALP), Ki67, osteocalcin (OC), collagen-I (Col-I) and Integrin ß1 mRNA in the cultured cells were determined by RT-PCR. As a result, Ta-xZr (x = 20, 30, 40 and 50 at%) alloys were non-toxic and supported proliferation of the MG63 cells. The osteoblasts adhered to the Ta-xZr alloys, and subsequently spread and proliferated rapidly. Furthermore, the cells grown on Ta-20Zr and Ta-30Zr expressed high levels of ALP, Col I and OC, indicating that the Ta-xZr alloys can induce osteogenesis. In conclusion, Ta-xZr alloys promoted the adhesion, proliferation and osteogenic differentiation of MG63 cells. The Ta-xZr composites with a higher proportion of Ta exhibited superior osteogenic activity, and Ta-30Zr is therefore a promising alternative for Ti implants.

Evaluation of biocompatibility and osseointegration of Nb-xTi-Zr alloys for use as dental implant materials.

The aim of this study was to evaluate the biocompatibility and osteogenic potential of 50%Nb-xTi-Zr (NTZ,x= 20%, 30%, 40% by weight) alloys as compared with dental commercial pure titanium (cpTi). Cell cytotoxicity assay, fluorescence microscopy and electron microscopy were used to measure thein vitrobiocompatibility of NTZ. The expression of alkaline phosphatase (ALP), integrin ß1, osteocalcin (OC), Ki67 and collagen-I (Col-I) at the mRNA level was measured by real-time reverse transcription-polymerase chain reaction. Osseointegration ability was determined using x-ray evaluation and histological analysisin vivo. Compared with the MG63 cells grown on cpTi on day 3, the viability, adherence and proliferation rates of cells cultured on NTZ alloys were significantly improved (p< 0.05). Furthermore, similar expression levels of Ki67, Col-I, OC and ALP were found in the MG63 cells grown on NTZ alloys and those grown on cpTi. The Cbfα1 level was significantly higher for the 50%Nb-30%Ti-Zr (NTZ3) than for the cpTi group on day 6 (p< 0.01), indicating that NTZ alloys can induce osteogenesis. A considerable amount of new bone formation and osseointegration was observed around NTZ3 implants compared with cpTi implantsin vivo. Collectively, NTZ3 showed superior biocompatibility and osteogenic activity; therefore, NTZ3 may be an excellent replacement for dental Ti implants.

Acyl Radicals from α-Keto Acids: Metal-Free Visible-Light-Promoted Acylation of Heterocycles.

A general and metal-free visible-light-induced decarboxylative arylation procedure at room temperature was described for the construction of acylated heterocyclic derivatives, such as benzimidazo/indolo[2,1-a]isoquinolin-6(5H)-ones, aroylazaspiro[4.5]trienones, thioflavones, and so on. This practical arylation procedure was conducted by using 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst under mild conditions, which avoided the use of an additional base, traditional heating, and metal reagents.

Effect of Bushen Huoxue decoction on inhibiting osteogenic differentiation of vascular smooth cells by regulating OPG/RANK/RANKL system in vascular calcification.

BACKGROUND: To investigate the effects of Bushen Huoxue Decoction (BSHXD) and its underlying molecular mechanisms on inhibiting osteogenic differentiation of vascular smooth muscle cells (VSMCs) in vascular calcification via regulating the mRNA expression of osteoprotegerin (OPG) and the receptor activator of the nuclear factor-kappa B ligand (RANKL). METHODS: VSMCs from the aortas of rats were cultured in vitro. Osteogenic differentiation of VSMCs was induced by high levels of an inorganic phosphate medium (2.4 mM). BSHXD-containing serum was prepared using the serum-pharmacological method. VSMCs were plated using 6-well plates at an approximate density of 4.0×104 cells/mL and cultured for 10 days. This was followed by the application of different concentrations of BSHXD-containing serum. The percentage of concentrations of BSHXD-containing serum in high, middle and low dosage group was 20%, 10% and 5%, respectively. Calcium nodules were evaluated by alizarin red S staining, and alkaline phosphatase (ALP) activity and calcium deposition were both examined as per the instruction of the test kits on the 3rd, 6th, and 10th days. Protein expression level of ALP and α-smooth muscle actin (α-SMA) were detected by Western blot on the 3rd, 6th, and 10th days. The mRNA expression of the OPG and RANKL were also detected by real-time PCR on the 3rd, 6th, and 10th days. RESULTS: Compared with the control group, BSHXD significantly attenuated the calcium nodules that were examined by alizarin red-S staining. Protein expression levels of α-SMA were up-regulated and ALP were down-regulated on the BSHXD group (P<0.05). BSHXD also attenuated the ALP activity and calcium deposition of the VSMCs (P<0.05). These changes were associated with the effect of BSHXD on up-regulating the expression of OPG mRNA and down-regulating the expression of RANKL mRNA in the process of osteogenic differentiation of VSMCs. CONCLUSIONS: BSHXD has a beneficial effect on inhibiting osteogenic differentiation of VSMCs induced by high levels of phosphate. The underlying mechanism appears to be related to the modulation of expressions of OPG mRNA and RANKL mRNA in the VSMCs, thereby preventing the phenotypic changes of VSMCs to an osteogenic phenotype.

Downregulation of p66Shc can reduce oxidative stress and apoptosis in oxidative stress model of marginal cells of stria vascularis in Sprague Dawley rats.

BACKGROUND: p66Shc, a Src homologue and collagen homologue (Shc) adaptor protein, mediates oxidative stress signaling. The p66Shc-null mice have increased lifespan and enhanced resistance to oxidative stress. Studies have also indicated its potential role in inner ear aging, which can lead to deafness. OBJECTIVE: The aim of this study was to determine the effects of p66Shc down-regulation on the marginal cells (MCs) of the inner ear stria vascularis. METHODS: Primary MCs were isolated from neonatal rats and treated with glucose oxidase to induce oxidative stress. The cells were transduced with adenovirus expressing siRNA, and the knockdown was verified by Western blotting. The reactive oxygen species (ROS) levels and apoptosis were analyzed using the DCFH-DA probe and Annexin-V/7-AAD staining respectively. The ultrastructure of the differentially-treated cells was examined by transmission electron microscopy (TEM).Results: The in vitro oxidative stress model was established successfully in rat MCs. Knockdown of p66Shc alleviated the high ROS levels and apoptosis in the glucose oxidase-treated cells. In addition, glucose oxidase significantly increased the number of peroxisomes in the MCs, which was decreased by p66Shc inhibition. CONCLUSION: Oxidative stress increases p66Shc levels in the marginal cells of the inner ear, which aggravates ROS production and cellular injury. Blocking p66Shc expression can effectively reduce oxidative stress and protect the MCs.

Short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type VI adult degenerative scoliosis.

BACKGROUND: The effect of short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type VI adult degenerative scoliosis (ADS) has not been clarified. This study aimed to compare the clinical and radiographic results of short-segment fusion vs. long-segment fusion and osteotomy for patients with Lenke-Silva type VI ADS. METHODS: Data of 28 patients who underwent spinal surgery for ADS from January 2012 to January 2014 in the General Hospital of Northern Theater Command were reviewed. Of the 28 patients, 12 received long-segment fusion and osteotomy and 16 received short-segment fusion. Radiographic imaging parameters and clinical outcomes, including the sagittal vertical axis (SVA), lumbar lordosis (LL) angle, pelvic tilt (PT), sacral slope (SS), the visual analog scale (VAS), Japanese Orthopedic Association (JOA), Oswestry disability index (ODI), and lumbar stiffness disability index (LSDI) scores, were recorded. The difference between groups was compared using the dependent t test or Chi-squared test. RESULTS: The Cobb and LL angles and SVA improved in both groups; however, PT and SS angles did not improve following short fusion. There were significant differences in the post-operative SVA (26.8 ±â€Š5.4 mm vs. 47.5 ±â€Š7.6 mm, t = -8.066, P < 0.001), PT (14.7 ±â€Š1.8° vs. 29.1 ±â€Š3.4°, t = -13.277, P < 0.001), and SS (39.8 ±â€Š7.2° vs. 26.1 ±â€Š3.3°, t = 6.175, P < 0.001) between the long and short fusion groups. All patients had improved ODI, JOA, and VAS scores post-operatively (all P < 0.001), with no significant difference between the groups (all P > 0.05). The post-operative LSDI score was 3.5 ±â€Š0.5 in the long fusion group, which was significantly higher than that of the short fusion group (1.4 ±â€Š0.7; P < 0.001). CONCLUSIONS: The clinical outcomes of patients with Lenke-Silva type VI ADS who underwent short-segment decompression/fusion were comparable to those of patients who underwent long-segment decompression/fusion and osteotomy despite poor correction of sagittal imbalance. Moreover, short-segment decompression/fusion showed a short operation time and reduced surgical trauma.

Clinical features of HIV/AIDS patients presenting to an inner city clinic in Ho Chi Minh City, Vietnam.

An outpatient HIV clinic was opened in March 2005 in Binh Thanh District, a poor section of Ho Chi Minh City, Vietnam. Over 1500 patients were seen in the first year. The average age of patients was 27 years. Men represented 77% of the clinic population, women, 23% and children under the age of 16 years of age, 5% of the population. The most common risk factor among men was being an injecting drug user (IDU), 76%, and among women, being married to an IDU HIV-positive man, 35%. Physical signs of disease were uncommon: lymphadenopathy in 24% and hepatomegaly and splenomegaly in 4% and 3%, respectively. Men and women were anaemic at presentation, with a mean haemoglobin of 11.9 g/dL and 11.1 g/dL, respectively. An overwhelming majority of patients had profound immunodeficiency. The mean CD4+ cell count was 164 cells/mL and the median was 69 cells/mL. No correlation was found between the World Health Organization's stage of disease and the CD4+ cell count. Thus, the former is a poor predictor of immunity in this population. Data regarding opportunistic infections diagnosed at the first visit were studied. Candidiasis of the oral pharynx, oesophagus or vagina was found in 34.5% of the patients, and pulmonary and extrapulmonary tuberculosis was found in 32% of the patients. Pneumocystis carinii pneumonia (PCP) was diagnosed in only 3% of the patients. Cotrimoxazole prophylaxis is advocated for HIV-infected Vietnamese, but the incidence of PCP is negligible and resources could be spent elsewhere. The various opportunistic infections seen in this resource-poor clinic setting is likely to be a pattern of presentation of HIV-infected Vietnamese for some time to come.

Ultrasound assisted synthesis of 5,9-dimethylpentadecane and 5,9-dimethylhexadecane--the sex pheromones of Leucoptera coffeella.

Racemic 5,9-dimethylpentadecane and 5,9-dimethylhexadecane, the major and minor constituents, respectively, of the sex pheromone of Leucoptera coffeella, have been synthesized from citronellol in 56-58% overall yield through six steps. Ultrasound irradiation efficiently supported tosylation of alcohols (two steps) as well as the subsequent cross coupling reactions with the pertinent Grignard reagents (also two steps).