Search

In the presence of catalytic amounts of CeCl 3.7H 2O, [RuCl(benzene)(S)-SunPhos]Cl is a highly effective catalyst for the asymmetric hydrogenation of aromatic alpha-ketoesters. A variety of ethyl alpha-hydroxy-alpha-arylacetates have been prepared in up to 98.3% ee with a TON up to 10,000. Challenging aromatic alpha-ketoesters with ortho substituents are also hydrogenated with high enantioselectivities. The addition of CeCl 3.7H 2O not only improves the enantioselectivity but also enhances the stability of the catalyst. The ratio of CeCl 3.7H 2O to [RuCl(benzene)(S)-SunPhos]Cl plays an important role in the hydrogenation reaction with a large substrate/catalyst ratio.

Cesium phosphate modified zeolite catalysts were prepared by wet impregnation method. The reaction activity of monoethanolamine (MEA) dehydration was evaluated in a fixed-bed flow microreactor at atmosphere. The experimental results revealed the great effects of the zeolite type, Si/Al molar ratio, and cesium content in catalysts on the reaction activity of MEA dehydration. Modified Hβ zeolite catalyst is favor of producing 2-methylpyrazine and 2-ethylpyrazine, and modified H-ZSM-5 zeolite catalyst is favor of producing triethylenediamine. With the increase of Si/Al ratio between 25 and 100 in modified H-ZSM-5 zeolite catalysts, piperazine and ethylenimine (EI) selectivity increased. With the changing of cesium content in modified H-ZSM-5 zeolite catalysts, 84.1% EI selectivity and 84.1% MEA conversion in MEA dehydration reaction were obtained.

Ru-SUNPHOS catalyzed asymmetric hydrogenation of a variety of sulfonyl ketones (R = alkyl, aryl) in the presence of iodine gave enantioenriched hydroxyl sulfones with good catalytic efficiency. Further investigation revealed that the in situ generated anhydrous HI is the operating additive.

The aim of this study was to design novel mixed micelles as an ophthalmic delivery system for alpha-tocopherol (TOC) to prevent its degradation and improve ocular efficacy. The nonionic polymers, Polyoxyl 15 Hydroxystearate (Solutol® HS15) and Pluronic® F127, were discovered to be the most effective agents for retaining the activity and solubilization of TOC, respectively. Prepared by a thin-film hydration method, HS15/Pluronic® F127 yielded good encapsulation percentages of TOC, with a 27.7% drug loading efficiency. Incorporation of cetalkonium chloride (CKC) into HS15/Pluronic® F127 mixed micelles made the zeta potential of the micelles +17 mV, potentially prolonging the residence time of formulations on ocular surfaces. The optimized micelle preparation remained stable when diluted in a synthetic tear solution. It is known that the antioxidant ability of TOC in typical formulations reduces to around 85% of its initial value after 1 month when stored at 4 or 25 °C under an air atmosphere, which limits ophthalmic applications to less than 1 month. However, encapsulated TOC in investigated micelles remained stable for at least 6 months when sealed with N2. Finally, the cationic micelles were well tolerated after multiple administrations in rabbits, and they improved ocular accumulation of TOC. Taken together, these data suggest that the optimized micelle preparations described in this study may be suitable drug carriers for the treatment of ocular oxidant damage.

Electrical capacitance tomography (ECT) is a relatively mature non-invasively imaging technique that attempts to map dielectric permittivity of materials. Recently, 3D ECT has gained interest because of its potential to generate volumetric images. In this paper, two kinds of 3D capacitance imaging sensors with 12 electrodes are researched by Finite Element simulation. The effect of rotation of the electrodes on the sensor output, sensitivity distributions and image reconstruction is studied. Based on comparative analysis, better sensor structure are determined. Keywords-electrical capacitance tomography; 3D ECT sensor; 3D sensitivity distribution; 3D reconstruction

The influence of high magnetic fields up to 10 T on the peritectic temperature of Bi–Mn alloys has been investigated experimentally. A method for measuring the peritectic temperature in a gradient magnetic field has been developed by relating the change of magnetic levitation force to the phase transformation due to the change in magnetic susceptibility while the transformation occurs. By measuring the temperature at which the magnetizing force changes abruptly, the phase transformation can be detected. It is shown that along with the increase of magnetic field, the temperature of the peritectic phase transformation BiMn 1.08 + L→BiMn increased significantly, and in a 10 T field the temperature increase was about 20 ∘ C. It is found that with the high magnetic field, a split and separation of the BiMn grains in the direction perpendicular to the magnetic field occurred, and its morphology changed from flakes to small blocks. This is attributed to the repulsive force among the peritectic BiMn grains generated by the magnetization during the phase transformation. It seems that the precipitation of ferromagnetic phase results in stress in the grains.

A palldium(0)-catalyzed tandem cyclization/Suzuki coupling reaction of various 1,6-enyne substrates was developed. This Pd-catalyzed enyne cyclization reaction represents a new process for the synthesis of stereodefined alpha-arylmethylene-gamma-butyrolactones, lactams, multifunctional tetrahydrofurans, pyrrolidines, and cyclopentanes. The mechanism of the reaction was studied by the employment of different enyne isomers and boronic acids; a pi-allyl palladium intermediate was suggested to explain the formation of the cyclic products. The stereochemistry of this reaction can be well explained by a chairlike transition state.

Three new biaryl phosphine ligands 4a – c have been prepared and their application in the Ru-catalyzed asymmetric hydrogenation of β-ketoesters investigated. Ruthenium catalysts containing these ligands are highly effective in the hydrogenation of β-ketoesters with up to 99.9% ee being obtained.

OH radical-initiated atmospheric oxidation of ethyl acrylate (ethyl 2-propenoate, EA) has been investigated by performing density functional theory (DFT) calculations. Optimizations of the reactants, intermediates, transition states and products were carried out at the MPWB1K/6-31+G(d,p) level. Single-point energy calculations were performed at the MPWB1K/6-311+G(3df,2p) level of theory. The detailed oxidation mechanism was presented and discussed. The results show that the OH addition is more energetically favorable than the H abstraction. Rice–Ramsperger–Kassel–Marcus (RRKM) theory was used to predict the rate constants over the possible atmospheric temperature range of 180–370 K. The Arrhenius expression adequately describes the total rate constant: k (EA+OH) = (1.71 × 10 −12 )exp(805.42/ T ) cm 3 molecule −1 s −1 . At 298 K, the atmospheric lifetime of ethyl acrylate determined by OH radicals is about 16.2 h. In order to find out the effect of alkyl substitution on the reaction activity, rate constants for the reactions of methyl acrylate, methyl methacrylate and butyl acrylate with OH radicals were also discussed. Calculation results show that the reaction activity may increase with the increased electron-donating substitution for electrophilic addition reaction.

Ontology, as a knowledge representation approach, continues to evolve over time as the domain develops. It is of particular importance when introducing ontologies into the information integration field, to eliminate semantic conflicts brought about by changes along the time axis. This paper first introduces a temporal ontology model which can be used to express and deal with time related information, then defines a set of rich query operators and a basic reasoning operator. Further, a prototype Temporal Ontology Management System (TOMS) enhanced with the above operators is applied to an information integration background with temporal semantic conflicts. Testing shows that TOMS is both capable of managing temporal ontologies and supporting temporal queries and basic reasoning.

[reaction: see text] An efficient asymmetric hydrogenation of alpha-ketoesters is reported with use of a catalyst prepared from [Ru((S)-3)(benzene)Cl]Cl and CeCl(3).7H(2)O. Alpha-hydroxy esters are obtained in up to 96% ee. The addition of CeCl(3).7H(2)O not only improves the enantioselectivity, but also enhances the stability of the catalyst. As a result, the hydrogenation of methyl benzoylformate affords the product with 92% ee with a substrate/catalyst ratio of 10 000. Hydrolysis of 2 provides the final compound with 83% yield at 99% ee after a single recrystallization from 1,2-dichloroethylene.

The aim of the present study was to investigate the underlying mechanism(s) involved in reversing multidrug resistance (MDR) of SK-N-SH/MDR1 by low-intensity pulsed ultrasound (LIPUS). Membrane alteration of SK-N-SH/MDR1 cells exposed to LIPUS was analyzed by scanning electron microscopy (SEM). Immunofluorescence and western blotting were used\ to detect changes in the expression of the MDR-related proteins P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1) and glutathione-s-transferase-π (GST-π) after the optimum ultrasonic. The optimum ultrasonic conditions were 0.3 MHz, 1.0 W/cm², 40 sec and the chemosensitivity of SK-N-SH/MDR1 cells was significantly increased (P0.05). The optimum ultrasonic-induced perforation of the irradiated cell membranes was observed by SEM. The expression of P-gp was significantly decreased in the group treated by optimum ultrasonic (P0.05), but not the expressions of MRP1 or GST-π (P0.05). We demonstrated that LIPUS effectively reverses the MDR of SK-N-SH/MDR1, presumably via augmenting membrane permeability and decreasing the P-gp expression of SK-N-SH/MDR1.

Pediatric acute care nurses questioned the practice of weighing disposable infant diapers immediately after voiding. This study asked the research question, "Does volume of saline, diaper configuration, and/or size of diaper statistically effect changes in diaper weights over time?" The method was an experimental, laboratory model. Pre-set volumes of saline were added to disposable diapers that were then left folded or unfolded. Each diaper was weighed immediately post-wetting and re-weighed at hourly intervals for seven hours. Data were analyzed using a repeated measures analysis of variance (RMANOVA) with balanced data (F-test). Diaper weight changes over time were statistically significant for all time points and for all volumes regardless of diaper size; however, the changes in weight were small and without clinical significance. It is appropriate to weigh diapers at the end of eight hours without risk of altering subsequent fluid management of patients in open-air, non-humidified environments. This practice has led to more efficient use of nurses' time with fewer interruptions for patients and families.

Density functional theory (DFT) and ab initio method are employed to elucidate the mechanisms for O 3 -initiated oxidation of n -butyl vinyl ether ( n -BVE) and its isomers ( i -BVE and t -BVE). For each BVE, the reactions proceed via O 3 cycloaddition resulting in the formation of primary ozonides (POZs) and then two self-decomposition pathways of POZs are followed. Major products are identified to be formaldehyde and butyl formates (CH 3 CH 2 CH 2 CH 2 OCHO for n -BVE, (CH 3 ) 2 CHCH 2 OCHO for i -BVE and (CH 3 ) 3 COCHO for t -BVE). The total and individual rate constants for main product channels have been calculated using the modified multichannel Rice–Ramsperger–Kassel–Marcus (RRKM) approach. At 298 K and 101 kPa, the calculated total rate constants are 2.50 × 10 −16 , 3.41 × 10 −16 and 4.17 × 10 −16 cm 3 molecule −1 s −1 for n -BVE + O 3 , i -BVE + O 3 and t -BVE + O 3 , respectively, which are in perfect agreement with experimental results. The total rate coefficients are almost pressure independent in the range of 0.001–101 kPa but obviously positive temperature dependent over the whole study temperature range (200–400 K). Also, the favorable reaction pathways have been determined through the estimation of branching ratios. Moreover, the influence of alkoxy group structure on the reactivity of vinyl ethers was examined.

To measure reader agreement in determining whether lung nodules detected at baseline screening computed tomography (CT) had changed at subsequent screening examinations and to evaluate the variability in recommendations for further follow-up.All subjects were enrolled in the National Lung Screening Trial (NLST), and each participant consented to the use of their de-identified images for research purposes. The authors randomly selected 100 cases of nodules measuring at least 4.0 mm at 1-year screening CT that were considered by the original screening CT reader to be present on baseline CT scans; nodules considered by the original reader to have changed were oversampled. Selected images from each case showing the entire nodule at both examinations were preloaded on a picture archiving and communication system workstation. Nine radiologists served as readers, and they evaluated whether the nodule was present at baseline and recorded the bidimensional measurements and nodule characteristics at each examination, presence or absence of change, results of screening CT, and follow-up recommendations (high-level follow-up, low-level follow-up, no follow-up).On the basis of reviews during case selection, five nodules seen at follow-up were judged not to have been present at baseline; for 19 of the remaining 95 cases, at least one reader judged the nodule not to have been present at baseline. For the 76 nodules that were unanimously considered to have been present at baseline, 21%-47% (mean ± standard deviation, 30% ± 9) were judged to have grown. The κ values were similar for growth (κ = 0.55) and a positive screening result (κ = 0.51) and were lower for a change in margins and attenuation (κ = 0.27-0.31). The κ value in the recommendation of high- versus low-level follow-up was high (κ = 0.66).Reader agreement on nodule growth and screening result was moderate to substantial. Agreement on follow-up recommendations was lower.

The novel gene HA117 is a multidrug resistance (MDR) gene in all-trans retinoic acid resistance HL-60 cells. The transduction of adenovirus vectors encoding HA117 conferred breast cancer cell line 4T1 MDR not only to MRP1 substrate drugs but also to MRP1 non-substrate drugs and the MDR strength of HA117 was similar to that of multidrug resistance-associated protein-1 (MRP1) for MRP1 substrate, but HA117 had no daunorubicin-excretion function.

OBJECTIVE: Population-based asthma detection is a potential strategy to reduce asthma morbidity in children; however, the burden of respiratory symptoms and health care use among children identified by case detection is not well known. METHODS: Data come from a school-based asthma case detection validation study of 3539 children. Respiratory symptoms, emergency department (ED) visits, and hospitalizations were assessed by questionnaire for children whose case detection result and physician study diagnosis agreed. RESULTS: Physician evaluation of 530 case detection results yielded 420 cases of agreement (168 children with previously diagnosed asthma, 39 with undiagnosed asthma, and 213 without asthma). Children with previously diagnosed asthma were more likely to be male (P < .0001). No differences in severity were observed in children with previously and undiagnosed asthma (P = .31). Children with undiagnosed asthma reported less frequent daytime and nighttime symptoms than children with previously diagnosed asthma but more than those without asthma (P < .0001). The proportion of children with at least 1 respiratory-related ED visit in the past year was 32%, 3%, and 3% for those with previously diagnosed, undiagnosed, and no asthma, respectively (P < .0001). The proportion with at least 1 respiratory-related hospitalization was 8%, 0%, and 0%, respectively (P < .0001). There were no differences in nonrespiratory ED visits (P = .93). CONCLUSIONS: Despite similar physician-rated severity, children with undiagnosed asthma reported significantly less frequent respiratory symptoms and health care use than children with previously diagnosed asthma. These findings suggest that the potential health gains from case detection may be smaller than expected.

Twenty-four–hour dietary recalls are used frequently to study homebound older adults' eating behaviors. However, the reliability and predictive validity of this method have not been established in this population. The purpose of this study was to examine whether homebound older adults provide reliable and valid measures of total energy intake in 24-hour dietary recalls. Two hundred thirty homebound older adults were interviewed in their homes using a questionnaire to assess eating behaviors and factors that could affect those behaviors. Participants completed three 24-hour dietary recalls at baseline and again at 6-month follow-up. Two subsamples were identified for analyses. For participants who were not hospitalized during the 6-month interval and had their weight measured at both assessments (n=52), sufficient test–retest reliability of energy intake was observed ( r =0.59), but energy intake deficiencies relative to estimated energy requirements did not predict actual weight loss ( r =0.08). When this sample was supplemented with 91 participants who experienced any adverse event (weight loss of 2.5% or more, hospitalization, institutionalization, or mortality) in the 6-month period (n=143), adverse events were more likely to occur for those with insufficient energy intake (odds ratio 3.49, P =0.009), and in white participants compared to African-American participants (odds ratio 3.13, P =0.016). Adequate test–retest reliability of the 24-hour dietary recall was demonstrated, but additional research with larger samples and longer follow-up intervals is needed to better evaluate the predictive validity of energy intake measures for this population.

In the presence of catalytic amounts of CeCl3·7H2O, [RuCl(benzene)(S)-SunPhos]Cl is a highly effective catalyst for the asymmetric hydrogenation of aromatic α-ketoesters. A variety of ethyl α-hydroxy-α-arylacetates have been prepared in up to 98.3% ee with a TON up to 10 000. Challenging aromatic α-ketoesters with ortho substituents are also hydrogenated with high enantioselectivities. The addition of CeCl3·7H2O not only improves the enantioselectivity but also enhances the stability of the catalyst. The ratio of CeCl3·7H2O to [RuCl(benzene)(S)-SunPhos]Cl plays an important role in the hydrogenation reaction with a large substrate/catalyst ratio.

Ru-SUNPHOS catalyzed asymmetric hydrogenation of a variety of sulfonyl ketones (R = alkyl, aryl) in the presence of iodine gave enantioenriched hydroxyl sulfones with good catalytic efficiency. Further investigation revealed that the in situ generated anhydrous HI is the operating additive.

Copolymerization of tetrahydrofuran and propylene oxide catalyzed by modified H2SO4.SO3 system has been studied. Sodium perchloride was used to replace perchloric acid as co-catalyst. The copolymerization rate was obviously accelerated when using the new H2SO4.SO3−NAClO4 catalyst system. The reaction became less sensitive to the moisture.

Aldehyde compounds exhibit very high reactivities towards ceric salt in initiating polymerization of acrylamide. In the presence of aldehyde compounds, the rate of polymerization is 8 times as high as the rate initiated by ceric salt alone. In nitric acid solution, the rate of polymerization decreases, but the accelerating effect of aldehyde compound becomes more obvious. Polyether prepolymer with aldehyde and groups also shows high activity towards ceric salt, with a relative rate of polymerization up to ca. 15, which can initiate acrylamide polymerization to form a block copolymer. The polymerization of acrylonitrile and methyl methacrylate initiated with ceric salt/aldehyde were also investigated.

Meng Bu,1,2 Jingling Tang,3 Yinghui Wei,4 Yanhui Sun,1 Xinyu Wang,1 Linhua Wu,2 Hongzhuo Liu1 1School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China; 2Department of Pharmacy, the Second Affiliated Hospital, 3School of Pharmacy, Harbin Medical University, Harbin, People’s Republic of China; 4College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China Purpose: Supplementation of exogenous nerve growth factor (NGF) into the cochlea of deafened animals rescues spiral ganglion cells from degeneration. However, a safe and potent delivery of therapeutic proteins, such as NGF, to spiral ganglion cells remains one of the greatest challenges. This study presents the development of self-assembled cubic lipid-based crystalline nanoparticles to enhance inner ear bioavailability of bioactive NGF via a round window membrane route.Methods: A novel nanocarrier-entrapped NGF was developed based on phytantriol by a liquid precursor dilution, with Pluronic® F127 and propylene glycol as the surfactant and solubilizer, respectively. Upon dilution of the liquid lipid precursors, monodispersed submicron-sized particles with a slight negative charge formed spontaneously.Results: Biological activity of entrapped NGF was assessed using pheochromocytoma cells with NGF-loaded reservoirs to induce significant neuronal outgrowth, similar to that seen in free NGF-treated controls. Finally, a 3.28-fold increase in inner ear bioavailability was observed after administration of phytantriol lipid-based crystalline nanoparticles as compared to free drug, contributing to an enhanced drug permeability of the round window membrane. Conclusion: Data presented here demonstrate the potential of lipid-based crystalline nanoparticles to improve the outcomes of patients bearing cochlear implants. Keywords: nerve growth factor, lipid-based crystalline nanoparticles, PC12 cells, inner ear drug delivery, bioavailability

The synthesis and resolution of a bulky and electron-rich derivative of SEGPhos and its application in Ru-catalyzed asymmetric hydrogenation reaction of beta-ketoesters are reported. Up to 99.5% ee was achieved. Under solvent-free reaction conditions, acetoacetates could be reduced with good enantioselectivity and high efficiency; a TON of 20 000 was obtained within 3.5 h. The results obtained were comparable to those when SEGPhos was applied.

An efficient Pd-catalyzed Sonogashira coupling reaction was achieved in the absence of a copper salt or amine with an inorganic base and easily prepared, air-stable aminophosphine ligands in commonly used organic solvents; good to excellent yields were obtained. Under optimized reaction conditions, the Sonogashira coupling reaction occurred selectively when an enyne substrate was employed and no Heck reaction product was detected; acetone-masked acetylene and trimethylsilylacetylene can also be efficiently coupled, providing a method to make terminal alkynes.

A convenient and practical method for the selective reduction of C=O bond of a wide spectrum of α-keto β,γ-unsaturated esters via transfer hydrogenation reaction under the catalysis of Ru(p-cymene)(TsDPEN) (TsDPUN: monotosylated 1,2-diphenylethylene-1,2-diamine) was developed.

Structure tailoring of hybrid nanoparticles is highly desirable for a number of applications, due to their controllable physical properties. Here, a family of Ag–Fe3O4 nanohybrids is synthesized via a simple one-step reaction of silver acetate and iron acetylacetonate in the presence of 1,2-dodecanediol, oleylamine and oleic acid. The as-obtained Ag–Fe3O4 nanohybrid could be finely tuned from heterodimer nanoparticles to flower-like or core–shell nanoparticles, by controlling the experimental conditions. The structural differences between these nanohybrids greatly affect their optical properties. The intense surface plasmon resonance (SPR) peak allows the heterodimer nanoparticles to act as a superior surface-enhanced Raman scattering (SERS) substrate, which has been demonstrated by using 2-naphthalenethiol as a probe molecule. It is noted that the SERS signal of 2-naphthalenethiol on the heterodimer nanoparticles is much stronger than those on the core–shell nanohybrid and Ag nanoparticles alone, indicating its potential in the fields of ultrasensitive detection and biological imaging.