Search

The kinetics of dimethyl 1,4‐cyclohexanedicarboxylate (DMCD) hydrogenation, via the half‐hydrogenated product methyl 4‐(hydroxymethyl) cyclohexanecarboxylate (MHMCC), to 1,4‐cyclohexanedimethanol (CHDM) in gas phase was established over CuMnAl catalyst. The intrinsic kinetic experiments were carried out on a fixed‐bed reactor under a wide range of reaction conditions with temperature varied from 493 to 523 K, pressure varied from 4 to 6 MPa, and weight hourly space velocity of DMCD varied from 0.948 to 3.792 h−1. Eight rival possible two‐site LHHW models were proposed to simulate the experimental results. The model involving dissociative adsorption of esters and surface reaction as the rate‐determining step was found to fit the experimental data best. The rather large activation energy values (138.4 and 121.4 kJ·mol−1) of two reactions (DMCD to MHMCC and MHMCC to CHDM) suggest that the reactions are both temperature sensitive. The coefficients of determination (R2) for DMCD conversion and CHDM selectivity were 0.989 and 0.983 respectively. Statistical and thermodynamic test further verified the reliability of the results. [ABSTRACT FROM AUTHOR]

The catalytic activity of an ionic liquid catalyst decreased during the transesterification of propylene carbonate (PC) with methanol to dimethyl carbonate (DMC). The interaction between the strong basic sites of ionic liquid catalyst and carbonyl compounds of PC and/or DMC was considered to attribute to this deactivation. The presence of H2O accelerated this process by the formation of OH–. The strong basic ionic liquid reacted with the trace amount of H2O in the reaction system to generate OH–, which then reacted with the carbonyl structure in PC and/or DMC to form the inactive compound HCO3–, resulting in the deactivation of the ionic liquid catalyst. A plausible mechanism was proposed for the deactivation of the ionic liquid catalyst in this reaction. [ABSTRACT FROM AUTHOR]

Amino‐functionalized halide ionic liquids, aminopropyl‐3‐butyl‐imidazolium ([Apbim]+) with different halogen anions, and their zinc halide mixing catalysts were prepared and used to catalyze the cycloaddition of CO2 to propylene oxide (PO) without solvent. Under ideal conditions, the conversion of PO could reach 93.5 % with the catalysis of [Apbim]Cl. Under optimized conditions of catalyst dosage, reaction temperature, CO2 pressure, and reaction time, with the catalysis of [Apbim]I, [Apbim]Cl/ZnBr2 (3:1), and [Apbim]Br/ZnBr2 (5:1), the conversion of PO and the selectivity of propylene carbonate (PC) both reach > 99 %. From the point of view of preparation process and industrial operation, [Apbim]Cl/ZnBr2 is the most suitable catalyst. This catalyst is characterized by good reusability and catalytic activity, and the yield of PC is about 99 % at least for ten times repeated use. [ABSTRACT FROM AUTHOR]

The transesterification of dimethyl carbonate with phenol to methyl phenyl carbonate (MPC) was investigated on novel catalysts such as titanium diisopropoxide bis(ethyl acetoacetate) and titanium dibutoxide bis(ethyl acetoacetate) in a closed batch reactor at 185–206 °C under high pressure. The produced methanol could be removed efficiently by reactive distillation in order to overcome the equilibrium. The prepared catalysts have higher resistance to water than titanium alkoxides. Phenol conversion as high as 86.4 % with an MPC selectivity of 99.4 % was achieved under optimal reaction conditions within 9 h. Most of the catalytic activity was retained after repeated use for ten times. [ABSTRACT FROM AUTHOR]

The deactivation of Pt/WOx/Al2O3 and Pt-Ru/WOx/Al2O3 catalysts in the glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO) was investigated in autoclave. The selectivity of both catalysts toward 1,3-PDO was within 50–56% after the first five usages at 170 °C for 12 h with a H2 pressure of 9 MPa. With Pt/WOx/Al2O3, the conversion of glycerol decreased from 44.3% (1st reaction) to 27.2% (5th reaction), whereas a conversion of 52.4%, 48.0%, and 48.4% was obtained in the 1st, 5th, and 20th reactions, respectively, when Pt-Ru/WOx/Al2O3 was used. The characterizations of the catalysts showed that the pore structure of the catalyst changed because of the crystal structure of the catalyst support changing from γ-Al2O3 to pseudo-boehmite. However, the changes of the catalyst morphology were not responsible for the catalyst deactivation. Simultaneously, the acidity of catalysts was not shown to be a factor in their deactivation. On the other side, catalysts were not deactivated as a result of the loss of active components. Catalyst deactivation during glycerol hydrogenolysis was finally caused by the aggregation of active metal particles (Pt or Pt-Ru). [ABSTRACT FROM AUTHOR]

The effect of residual chlorine of alumina-supported Ni catalysts on the selective CO methanation reaction was investigated. By chloride addition to the catalyst, CO 2 methanation and the reverse water gas-shift reaction were significantly suppressed in the course of the reaction. FTIR measurements for CO 2 adsorption on a series of modified catalysts with various chlorine-containing additives revealed that chlorine suppressed the dissociation of CO 2 on the catalyst surface, which led to the formation of adsorbed CO species. The FTIR results combined with TPD measurements for CO 2 desorption indicates that chlorine adsorbed on Ni metal diminished the formation of carboxylate species on the same surface under flowing CO 2 conditions. Through the present study, the controlling factor for the selective methanation of CO by chlorine was clarified in high CO 2 concentration-containing hydrogen rich gas. [ABSTRACT FROM AUTHOR]

Abstract: We reported earlier that KNO3- and Pt-impregnated potassium titanate nanobelt (KTN) catalysts exhibit high storage capacity and excellent catalytic cycles for NO x storage-reduction (NSR) reaction. In the present study, we compared the NSR behavior of various alkali-metal-nitrate impregnated KTN catalysts, which revealed that the KNO3-impregnated catalyst exhibited superior performance. The XPS and XRD analyses of the NaNO3-impregnated KTN catalyst showed that the migration of K+ from KTN bulk to the surface nitrate salt took place more predominantly than the migration of Na+. Probably for this reason, KNO3-impregnated KTN materials exhibit the best performance for NSR catalytic cycles. [Copyright &y& Elsevier]

Abstract: Ordered mesoropous Ni–Al and Ni–Mg–Al oxides were prepared by evaporation induce self-assembly method using Pluronic P123 as a soft template. Ni–Al and Ni–Mg–Al oxides without P123 addition were also prepared. The prepared ordered mesoporous catalysts showed much higher activity and durability for dry reforming of methane than those without ordered mesoporous structure. The N2 sorption and transmission electron microscope observation revealed that the ordered structure was kept after reaction at 750°C for 30h. The sintering of Ni was prevented and the coke formation was suppressed on mesoporous catalysts. Although the addition of Mg was not so efficient for improving the activity of mesoporous catalyst, benefit for suppressing coke formation was observed. [Copyright &y& Elsevier]

Abstract: We have identified a new NO x storage/reduction catalyst with the composition of Pt–KNO3 supported on a K-titanate nanobelt (KTN) prepared using hydrothermal method. Isothermal NO x storage experiments at 350°C revealed the highest storage capacity (2.27mmol/g) ever achieved over 33wt.% KNO3 impregnated catalyst, and lean–rich cycles could be operated for more than 15 times with maintaining its high storage capacity. The characterization of the spent catalysts revealed that addition of more than 33wt.% KNO3 caused the gradual destruction of the nanobelt structure during the reaction and the decrease in NO x storage capacity. High temperature operation such as at 500°C also caused the destruction of nanobelt structure. It was demonstrated that the main storage specie of NO x was potassium nitrate. Immigration of K+ from and back to K-rich layers on KTN might be the mechanism for the storage and reduction of NO x on those materials. [Copyright &y& Elsevier]

Abstract: A new in situ reduction method has been developed to synthesize a novel structured MnO2/mesoporous carbon composites with MnO2 nanoparticles embedded in the wall of ordered mesoporous carbon CMK-3 materials. KMnO4 was easy to be reduced into MnO2 in a short time in the presence of carbon, meanwhile the carbon atoms on the surface were oxidized into C–OH, CH species, making the surface more hydrophilic, and permanganate ions more readily to access, which leads to the embedded structure. The MnO2/CMK-3 composite materials were characterized using thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), nitrogen sorption, transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) spectroscopy. The results show that different MnO2 contents could be introduced into the pores of CMK-3 treated with an aqueous solution of potassium permanganate, while retaining the ordered mesostructure and larger surface area. Increasing the MnO2 content did not result in a decrease in pore size from the data of nitrogen sorption isotherms, indicating that MnO2 nanoparticles are embedded in the pore wall, as evidenced by TEM observation. [Copyright &y& Elsevier]

Abstract: Mesoporous cerium dioxide has been synthesized using the ordered mesoporous silica KIT-6 as hard template. A series of different amounts of CuO have been modified to this CeO2 replica by wet impregnation. The XRD, SEM, TEM, N2 sorption measurement, and the CO catalytic oxidation reaction have been adopted to characterize those materials. CuO can be homogeneously loaded on this ceria replica. Compared with the porous CeO2 directly decomposed from the cerium nitrate hydrate, this CeO2 shows high catalytic reactivity for the CO oxidation, the T 50 on this ceria replica is 83K lower than on the decomposed ceria, and the CuO-loaded mesoporous ceria show more active for this catalytic reaction, the lowest T 50 is only 389K achieved at the 20% CuO loading. [Copyright &y& Elsevier]

Abstract: We report here a new route to prepare nanocrystalline β-silicon carbide with high specific surface areas and mesoporosity. The preparation method was via the reaction of ordered mesoporous carbons (OMCs, carbon replicas of MCM-48, SBA-15 and KIT-6) with silicon powder at the temperature of 1200–1300°C, which is below the melting point of silicon, 1420°C. The SiC samples were characterized by XRD, SEM, TEM, N2 adsorption and other techniques, which showed that the SiC samples were nanocrystalline and had a high surface area of up to 147m2 g−1 and a mesoporosity in the range of 5–40nm. In addition, the silicon vapor infiltration method at a temperature beyond 1420°C was also brought into comparison. [Copyright &y& Elsevier]

Abstract: A series of manganese-loaded mesoporous materials MCM-41 (MnMCM-x, x =0.005, 0.01, 0.05, and 0.1) were synthesized by a facile in situ reduction method with potassium permanganate (KMnO4) and the surfactant template. It was found from the results of Fourier transform infrared spectroscopy that, as the concentration of KMnO4 solution increased, the amount of remaining surfactant template in the pore channels decreased and meanwhile the content of loaded manganese increased. KMnO4 was found to be reduced to manganese oxides of low charge states of Mn by X-ray photoelectron spectroscopy. These results prove that the permanganate ions were reduced by the surfactant within the pores, rather than ion-exchanged by the D4R (negatively charge silica species) anions. Different contents of manganese species have been introduced by changing the initial concentration of KMnO4, and the ordered mesostructure has been kept with large surface area. [Copyright &y& Elsevier]

In order to prepare polyimide (PI) films with a low dielectric constant and excellent comprehensive performance, a two-step method was employed in this study to integrate β-cyclodextrin into a semi-aromatic fluorine-containing polyimide ternary system. By introducing trifluoromethyl groups to reduce the dielectric constant, the dielectric constant was further reduced to 2.55 at 10 MHz. Simultaneously, the film exhibited noteworthy thermal stability (a glass transition temperature exceeding 300 °C) and a high coefficient of thermal expansion. The material also demonstrated outstanding mechanical properties, boasting a strength of 122 MPa and a modulus of 2.2 GPa, along with high optical transparency (transmittance reaching up to 89% at 450 nm). Moreover, the inherent high transparency of colorless polyimide (CPI) combined with good stretchability contributed to the attainment of a low dielectric constant. This strategic approach not only opens up new opportunities for novel electroactive polymers but also holds potential applications in flexible displays, circuit printing, and chip packaging. [ABSTRACT FROM AUTHOR]

Background and Aims: Postoperative nausea and vomiting (PONV), one of the common complications following strabismus surgery, would delay the ambulatory discharge time. The aim of this retrospective study was to determine the risk factors of PONV in patients undergoing ambulatory strabismus surgery under general anaesthesia, with the treatments of dexamethasone and 5-HT3antagonist combination. Methods: We reviewed 721 consecutive patients (12–60 years old) undergoing ambulatory strabismus surgery under general anaesthesia at an academic eye centre between December 2016 and January 2019. Patients received prophylactic treatment of dexamethasone and 5-HT3antagonist combination during anaesthesia induction, and PONV was evaluated during the early recovery period before discharge. Results: The dexamethasone and 5-HT3antagonist combination effectively reduced the incidence of PONV (3.05%, 22/721), and the patients who experienced PONV had statistically prolonged phase II recovery time as compared those who did not (P = 0.006). The sum of the extraocular muscles manipulated and the use of nalbuphine (vs flurbiprofen axetil) were the independent risk factors for PONV (P < 0.05). Conclusion: The sum of the extraocular muscles manipulated and the use of nalbuphine are potentially modifiable risk factors for PONV after strabismus surgery with the treatments of dexamethasone and 5-HT3antagonist combination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Higher yield achieved on Zn-Al oxide than on ZnO and Al 2 O 3. • Zn and Al complex formed as homogeneous catalysts. • Precipitate continuously separated from the reactant after the consumption of urea. • Zn complex catalyze the main reaction and Al species delay the precipitation. ZnO, Al 2 O 3 , and Zn-Al oxide prepared from hydrotalcite-like compound, were evaluated for the catalysis of carbonylation of 1,2-propylene glycol (PG) with urea to propylene carbonate (PC) under the reduced pressure of 40 kPa at 170 °C. Zn-Al oxide achieved highest yield of PC (96.6%) among three catalysts when 0.5 wt% of catalyst was used. It was found that ZnO and Al 2 O 3 could be dissolved into the reactant to form Zn and Al complex during the reaction, but the dissolved amount of ZnO was much larger than Al 2 O 3. The reaction was experienced three states of catalyst dissolution, homogeneous catalysis and catalyst re-depositing. The essential role of Zn was to produce Zn(NCO) 2 (NH 3) 2 which in fact catalyzed the (2- or 4-)hydroxypropyl carbamate cycling to PC. Although Al 2 O 3 showed negligible catalytic activity for this reaction, the dissolved Al species (probably Al(NH 3)(NCO) 3) could delay the re-deposition of Zn complex and hence achieve high yield of PC on Zn-Al oxide. The re-deposited catalyst of ZnO and Zn-Al oxide contained counter anions of OH, CO 3 , and NCO. Some techniques were used for the characterizations of the spent catalysts. [ABSTRACT FROM AUTHOR]

In carbonylation of ethylene glycol to ethylene carbonate with urea catalyzed by ZnO, which was considered as a heterogeneous catalyst. ZnO is observed to be dissolved in the reactants probably due to the formation of Zn(NCO) 2 (NH 3 ) 2 making the reaction homogeneously catalyzed. To our knowledge, it is firstly reported that the reaction experienced three states including ZnO dissolution, homogeneous catalysis, and precipitate formation. The precipitate was characterized to be a mixture containing Zn(OH) 2 , ZnCO 3 , and Zn(NCO) 2 with a ratio of 8.5:6.1:1. Possible mechanisms of ZnO dissolution and precipitation were proposed. [ABSTRACT FROM AUTHOR]

A mesoporous silica-coated Ni-based catalyst was developed for selective CO methanation, which is a promising candidate as a new hydrogen purification process for residential polymer electrolyte fuel cell systems. The catalytic activity and CO removal ability of the Ni/AlVO x catalyst were significantly improved by the coating of mesoporous silica on the Ni/AlVO x . The Ni-V species transported from the Ni/AlVO x to the coating layer may also act as active sites for CO methanation and thus may have an essential role in the improvement of the catalytic activity. Fe addition to the catalyst was effective for the improvement of catalyst durability due to suppression of the deposition of carbonaceous species during the reaction. [ABSTRACT FROM AUTHOR]

A mesoporous silica-coated Ni/alumina-based catalyst was developed for selective CO methanation, which is a promising candidate as a new hydrogen purification process for a residential PEFC system. Over the new catalyst, CO removal activity and durability were dramatically improved. In this study, the structure of the catalyst and mechanism for the improvement of catalytic performance will be discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] SHP2 is required for EGFR inhibitor resistant NSCLC H1975 cell proliferation. [•] SHP2 inhibitor blocks EGF-stimulated ERK1/2 activation and proliferation. [•] SHP2 inhibitor exhibits marked anti-tumor activity in H1975 xenograft mice. [•] SHP2 inhibitor synergizes with PI3K inhibitor in suppressing cell growth. [•] Targeting SHP2 represents a novel strategy for EGFR inhibitor resistant NSCLCs. [ABSTRACT FROM AUTHOR]

This paper describes the scientific objectives and payloads of Tianwen-1, China's first exploration mission to Mars. An orbiter, carrying a lander and a rover, lifted-off in July 2020 for a journey to Mars where it should arrive in February 2021. A suite of 13 scientific payloads, for in-situ and remote sensing, autonomously commanded by integrated payload controllers and mounted on the orbiter and the rover will study the magnetosphere and ionosphere of Mars and the relation with the solar wind, the atmosphere, surface and subsurface of the planet, looking at the topography, composition and structure and in particular for subsurface ice. The mission will also investigate Mars climate history. It is expected that Tianwen-1 will contribute significantly to advance our scientific knowledge of Mars. [ABSTRACT FROM AUTHOR]

Procedural sedation for non-painful pediatric examinations outside the operating room remains a challenge, this study was designed to compare the safety and effectiveness of sedation provided by dexmedetomidine versus other sedatives including chloral hydrate, midazolam, and pentobarbital for pediatric patients to complete diagnostic examinations. Systematic review and meta-analysis of RCTs. Pediatric procedural sedation. Comparison of sedation by dexmedetomidine and chloral hydrate, or pentobarbital, or midazolam for pediatric non-painful sedation. The PubMed, Embase, and Cochrane Library databases and the Cochrane Controlled Trials Register for randomized clinical trials were searched and limited the studies to those published in English through July 30, 2018. Prospective randomized clinical trials (RCTs) comparing dexmedetomidine to chloral hydrate, pentobarbital, and midazolam for pediatric procedural examinations outside the operating room were included in the meta-analysis. Search terms included dexmedetomidine, precede, adrenergic alpha-2 receptor agonists, adrenergic alpha 2 agonists, adrenergic alpha-agonists, adrenergic alpha 2 receptor agonists, chloral hydrate, pentobarbital, midazolam, AND sedation. A total of 1486 studies were screened and nine RCTs were identified; 1076 patients were analyzed. Sedation with dexmedetomidine provided statistically higher incidences in completing examinations with fewer episodes of desaturation than the other sedatives did (OR 2.90, 95% CI: 1.39–6.07, P = 0.005, I2 = 77%; OR 0.29, 95% CI: 0.15–0.57, P = 0.0004, I2 = 0%, respectively). The meta-analysis shows that sedation by dexmedetomidine has lower incidence of respiratory depression and provides higher success rates in completing examinations than other traditional sedatives without compromising safety, indicating a prospective clinical use for procedural sedation. • Dexmedetomidine provides higher success rate in procedural sedation than chloral hydrate, pentobarbital and midazolam. • Dexmedetomidine in non-painful pediatric procedural sedation would not increase the respiratory adverse events. • Dexmedetomidine would be an optimal sedative for non-painful pediatric examinations. [ABSTRACT FROM AUTHOR]

Study Objective: Procedural sedation for non-painful pediatric examinations outside the operating room remains a challenge, this study was designed to compare the safety and effectiveness of sedation provided by dexmedetomidine versus other sedatives including chloral hydrate, midazolam, and pentobarbital for pediatric patients to complete diagnostic examinations.Design: Systematic review and meta-analysis of RCTs.Setting: Pediatric procedural sedation.Interventions: Comparison of sedation by dexmedetomidine and chloral hydrate, or pentobarbital, or midazolam for pediatric non-painful sedation.Patients: The PubMed, Embase, and Cochrane Library databases and the Cochrane Controlled Trials Register for randomized clinical trials were searched and limited the studies to those published in English through July 30, 2018.Measurements: Prospective randomized clinical trials (RCTs) comparing dexmedetomidine to chloral hydrate, pentobarbital, and midazolam for pediatric procedural examinations outside the operating room were included in the meta-analysis. Search terms included dexmedetomidine, precede, adrenergic alpha-2 receptor agonists, adrenergic alpha 2 agonists, adrenergic alpha-agonists, adrenergic alpha 2 receptor agonists, chloral hydrate, pentobarbital, midazolam, AND sedation.Main Results: A total of 1486 studies were screened and nine RCTs were identified; 1076 patients were analyzed. Sedation with dexmedetomidine provided statistically higher incidences in completing examinations with fewer episodes of desaturation than the other sedatives did (OR 2.90, 95% CI: 1.39-6.07, P = 0.005, I2 = 77%; OR 0.29, 95% CI: 0.15-0.57, P = 0.0004, I2 = 0%, respectively).Conclusions: The meta-analysis shows that sedation by dexmedetomidine has lower incidence of respiratory depression and provides higher success rates in completing examinations than other traditional sedatives without compromising safety, indicating a prospective clinical use for procedural sedation. [ABSTRACT FROM AUTHOR]

To develop and apply new type catalyst is an effective route for reducing the NOx emission. The catalytic reduction of NO by H 2 without O 2 could be used as a model reaction for the evaluation of a given catalyst. Cobalt doped nanoporous nickel phosphate VSB-5 is a recently developed catalyst and is firstly applied to catalytically reduce NO by H 2 in the absence of O 2 . NO can be catalytic reduced by H 2 on the prepared samples. The catalytic performance has close relations with the amount of doped cobalt and enhanced catalytic performance has been observed on cobalt substituted samples. Large amount of NO could be adsorbed on the surface of Co-VSB-5 which works as the active component during the catalytic process. Accordingly, a reaction mechanism is also proposed. The prepared catalyst may have potential application in the de-NOx process. [ABSTRACT FROM AUTHOR]

Background and aim Pediatric ophthalmic examinations can be conducted under sedation either by chloral hydrate or by dexmedetomidine. The objective was to compare the success rates and quality of ophthalmic examination of children sedated by intranasal dexmedetomidine vs oral chloral hydrate. Methods One hundred and forty-one children aged from 3 to 36 months (5-15 kg) scheduled to ophthalmic examinations were randomly sedated by either intranasal dexmedetomidine (2 μg·kg−1, n = 71) or oral chloral hydrate (80 mg·kg−1, n = 70). The primary endpoint was successful sedation to complete the examinations including slit-lamp photography, tonometry, anterior segment analysis, and refractive error inspection. The secondary endpoints included quality of eye position, intraocular pressure, onset time, duration of examination, recovery time, discharge time, any side effects during examination, and within 48 h after discharge. Results Sixty-one children were sedated by dexmedetomidine with a success rate of 85.9%, which is significantly higher than that by chloral hydrate (64.3%) [ OR 3.39, 95% CI: 1.48-7.76, P = 0.003]. Furthermore, children in the dexmedetomidine group displayed better eye position in anterior segment analysis than in chloral hydrate group median difference. All children displayed stable hemodynamics and none suffered hypoxemia in both groups. Oral chloral hydrate induced higher percentages of vomiting and altered bowel habit after discharge than dexmedetomidine. Conclusions Intranasal dexmedetomidine provides more successful sedation and better quality of ophthalmic examinations than oral chloral hydrate for small children. [ABSTRACT FROM AUTHOR]

ABSTRACT Biomimetic polyelectrolyte of Dopa modified poly(acrylic acid) (PAADopa) was synthesized taking advantage of Dopa, the major unit of marine adhesive proteins. Zinc crosslinked PAADopa (PAADopa-Zn) were formed at acidic pH for more compact structure and assembled with the positively charged polyethylenimine (PEI) to build robust polyelectrolyte multilayers at high salt concentration. Effects of pH, crosslinking degree, and salt concentration on polymer structure, film building process, and morphology were investigated, respectively. An 'odd-even' effect was observed by quartz crystal microbalance with dissipation and AFM in the presence of zinc ion, which becomes more obvious with an optimum crosslinking degree (Zn/Dopa = 2.0) under high salt concentration (0.6 M NaCl). It indicates the different swollen properties of PEI chain and PAADopa-Zn complexes during the layer-by-layer building process under optimum crosslinking degree of PAADopa-Zn at high salt concentration. Such odd-even phenomenon of the biocompatible system is of critical importance for understanding the mechanism of layer formation and film structures. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 245-255 [ABSTRACT FROM AUTHOR]

Study Objectives: This study aimed to test the hypothesis that premedication with a single dose of intranasal dexmedetomidine (DEX) could not only reduce preoperative anxiety but also minimize the emergence agitation in children undergoing cataract surgery with sevoflurane anesthesia.Design: Single-blinded, randomized, placebo-controlled clinical comparison study.Setting: Academic medical center.Patients: Ninety American Society of Anesthesiologists physical status 1 and 2 children scheduled for cataract surgery.Interventions: Patients were randomized into 3 groups: group D1, group D2, and saline group (group C), in which the children received 1 or 2 μg/kg of intranasal DEX or saline, respectively, and each group comprises 30 patients.Measurements: The mask induction score and the incidences of postoperative emergence agitation evaluated by the Pediatric Anesthesia Emergence Delirium scale were assessed. The emergence time, postanesthesia care unit (PACU) stay time, and any adverse events were recorded.Main Results: The mask induction scores were significantly higher in the saline group than those in the D1 and D2 groups (P<.001). The incidences of emergence agitation in the D1 and D2 groups were significantly lower than that in the saline group (7/30 in group D1 and 3/30 in group D2 vs 24/30 in group C, P<.001). The emergence time and PACU stay time were comparable among the 3 groups (P>.05). The emergence time and PACU stay time did not differ significantly in DEX-treated groups as compared with the saline group; there were no differences between 1- and 2-μg/kg groups. None of the patients exhibited significant clinical complications.Conclusion: Intranasal DEX (1 or 2 μg/kg) dose independently improves the incidences of mask acceptance and prevents the incidences of postoperative emergency agitation mainly from sevoflurane without delaying the emergency time or inducing severe adverse events. [ABSTRACT FROM AUTHOR]

To develop new catalyst for controlling NO emission is important for pollution control. The investigation of NO or CO adsorption could contribute the fundamental understanding the reaction mechanism of de-NOx process and the coordinate state of the specific catalyst. Nanoporous nickel phosphate VSB-5 is an attractive catalyst and is firstly employed as the active component for the adsorption of NO and/or CO. In situ FT-IR and temperature programmed desorption (TPD) are used to characterize the adsorption behaviors. A large amount of NO and/or CO can be adsorbed in the pores of VSB-5 and strong bands from different adsorbed species are observed by in situ FT-IR investigation, which is confirmed by isotopic labeled adsorption. The amount of adsorption at room temperature unusually increases by raising the adsorption temperature to 100–200 °C. The possible reason may be explained by the generation of more active sites at elevated temperature which plays a more important role than corresponding desorption. The adsorption of CO and NO is competitive and the adsorbed CO may be replaced by NO due to a stronger bonding strength of the latter. This report contributes to monitor the active sites in the pores of VSB-5 and also makes VSB-5 to be an active candidate for NO or CO related catalytic process. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Many studies have suggested that adiponectin gene might be involved in the development of coronary artery disease (CAD). However, the results have been inconsistent. In this study, the authors performed a meta-analysis to assess the associations of +45T/G, +276G/T and −11377C/G polymorphisms in adiponectin gene with CAD susceptibility. Methods: Published literature from PubMed and EMBASE databases were searched. Pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were calculated using fixed- or random-effects model. Results: Sixteen studies (4394 cases / 8187 controls) for +45T/G polymorphism, fifteen studies (3569 cases / 7463 controls) for +276G/T polymorphism, and thirteen studies (3531 cases / 7072 controls) for −11377C/G polymorphism were included in the meta-analysis. The overall results showed that there was a statistically significant association between −11377C/G polymorphism and CAD (G vs. C: OR=1.15, 95%CI 1.07-1.24).Similar results were observed among European (G vs. C: OR=1.11, 95%CI 1.02-1.20) and East Asian populations (G vs. C: OR=1.27, 95%CI 1.11-1.45). However, no significant association was found for +45T/G or +276G/T polymorphism with CAD susceptibility. Conclusions: The meta-analysis indicated the significant association of −11377C/G polymorphism, but not +45T/G or +276G/T polymorphism, with CAD susceptibility. However, large-scale studies with the consideration of gene-gene and gene-environment interactions should be conducted to investigate the associations in future. [Copyright &y& Elsevier]

Summary: SHP2 phosphatase is a positive transducer of growth factor and cytokine signaling. SHP2 is also a bona fide oncogene; gain-of-function SHP2 mutations leading to increased phosphatase activity cause Noonan syndrome, as well as multiple forms of leukemia and solid tumors. We report that tautomycetin (TTN), an immunosuppressor in organ transplantation, and its engineered analog TTN D-1 are potent SHP2 inhibitors. TTN and TTN D-1 block T cell receptor–mediated tyrosine phosphorylation and ERK activation and gain-of-function mutant SHP2-induced hematopoietic progenitor hyperproliferation and monocytic differentiation. Crystal structure of the SHP2⋅TTN D-1 complex reveals that TTN D-1 occupies the SHP2 active site in a manner similar to that of a peptide substrate. Collectively, the data support the notion that SHP2 is a cellular target for TTN and provide a potential mechanism for the immunosuppressive activity of TTN. Moreover, the structure furnishes molecular insights upon which therapeutics targeting SHP2 can be developed on the basis of the TTN scaffold. [ABSTRACT FROM AUTHOR]

Abstract: Hollow silica nanospheres containing various precious metal clusters such as Rh, Ir and Ru were synthesized by solubilizing corresponding metal ammine complexes into NP-6/cyclohexane reversed micelle system. The condensation and nucleation of the metal ammine complex in the reversed micelles took place and the resulting nanocrystals of the ammine complexes acted as a structure-directing agent for the formation of hollow cavity in silica spheres. The nano-hollow spheres were stable for thermal treatment up to 1073K. By this method, bimetallic nanoparticles, i.e. Rh–Co–SiO2 and Ir–Co–SiO2, were also easily synthesized and both metal elements containing in the hollows may be alloyed after thermal treatment. The Ir– and Rh–SiO2 nano-hollows exhibited excess hydrogen uptake. In particular, over Ir–SiO2 sample, the H/Ir ratios reached 3.3 under 200Torr of hydrogen at room temperature. At higher pressure, the H/M value reached 11.6 at 2.6MPa. [Copyright &y& Elsevier]

Abstract: Hollow mesoporous silica spheres with uniform size and morphology have been successfully synthesized in a facile route using PVP and CTAB as co-templates at room temperature. XRD, N2 adsorption–desorption analysis, FE-SEM, TEM and UV–vis are used for the characterization. The hexagonally ordered pore channels are formed on the shell. These hollow mesoporous silica spheres have been proven to store much more guest molecules than conventional MCM-41, with more than half of them being held in the hollow cores. [Copyright &y& Elsevier]

One-dimensional (1D) ZnO nanostructures were grown in amorphous SiO2 matrix by a co-templating method under hydrothermal condition. Using ethylenediamine (EDA) groups grafted mesoporous silica MCM-41 as a co-template, the growth of 1D ZnO nanostructures was oriented by soft EDA groups and confined inside the hard mesochannels of MCM-41. The microstructure and morphology of the 1D-ZnO-nanostructures/SiO2 composite were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). All these results indicate that the 1D ZnO nanostructures were synthesized and highly dispersed in the amorphous SiO2 matrix. Blue-shifted exciton absorption was observed from the co-templating synthesized sample. [Copyright &y& Elsevier]