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This paper presents rigorous analytical solutions for cavity contraction analysis of a thick-walled cylinder/sphere after an arbitrary magnitude of expansion. Closed-form solutions are given for the distribution of stress and displacement within the cylinder/sphere of soil that is subjected to constant external pressure and monotonically decreasing internal pressure. The soil is modelled as an elastic-perfectly plastic material obeying the Mohr-Coulomb yield criterion and a non-associated flow rule. Large strain effects are taken into account by adopting the logarithmic strain definition in the plastic deformation analysis. The new solutions are validated with published results at first, then parametric studies are carried out. It is shown that the reference stress state (e.g. in-situ, elastic, partially plastic and fully plastic) and the cavity geometry ratio may greatly affect the unloading behaviour, in particular, when the cavity geometry ratio is smaller than a limit value. Finally, three typical applications of the solutions are demonstrated, including (i) design of the thickness of frozen cylinder walls accounting for large deformation effects, (ii) interpretation of laboratory pressuremeter tests with consideration of effect of the constant stress boundary, and (iii) shakedown analysis of a soil cylinder/sphere considering its geometry changes upon cyclic loading and unloading. [ABSTRACT FROM AUTHOR]

Three new mexicanolide limonoids were obtained from the 90% ethanol extract of the seeds of Khaya senegalensis. Their structures were elucidated as senegalenines A–C (1–3) by analysing their 1D/2D NMR and MS spectroscopic analysis. In addition, the isolated limonoids were tested in vitro for antimicrobial potentials against 5 pathogenic microorganisms. Consequently, compounds 1–3 exhibited antimicrobial activity against the tested Gram negative bacteria at the minimum inhibitory concentration values less than 40 μg/ml. [ABSTRACT FROM AUTHOR]

Ottelia acuminata (O. acuminata) is an edible and medicinal submerged plant endemic to southwestern China, yet there is little information available concerning its nutritional or bio-active composition. This study aimed to evaluate in detail the nutritional profile and phenolic composition of O. acuminata (inflorescence, peduncle, and leaf) and investigate a protective activity in phenolic extracts on DNA damage induced by •OH and ROO• radicals. O. acuminata was excellent sources of protein (17.7–24 g/100 g DW), TPC (11.43–19.00 mg GAE/g DW), ascorbic acid, and minerals (especially potassium, calcium, and iron). Interestingly, the protein contained a high amount of EAA with a ratio (EAA11/TAA) in the range of 47.79–50.93%, BCAA and MSG-like AA. The inflorescences and leaves of O. acuminata contained abundant UFA with a ratio of UFA/TFA more than 50%. Five phenolic compounds, with a predominance of luteolin, luteolin-7-O-glucoside and chlorogenic acid, were identified by HPLC. Phenolic extracts of O. acuminata displayed a significant protective effect on DNA damage, which effect was comparable to that of the positive control (trolox). It was concluded that O. acuminata is an excellent vegetable with a high nutritional value and a great potential as a natural antioxidant. [ABSTRACT FROM AUTHOR]

Background: Probiotic lozenges have been developed to harvest the benefits of probiotics for oral health, but their long-term consumption may encourage the transfer of resistance genes from probiotics to commensals, and eventually to disease-causing bacteria. Aim: To screen commercial probiotic lozenges for resistance to antibiotics, characterize the resistance determinants, and examine their transferability in vitro. Results: Probiotics of all lozenges were resistant to glycopeptide, sulfonamide, and penicillin antibiotics, while some were resistant to aminoglycosides and cephalosporins. High minimum inhibitory concentrations (MICs) were detected for streptomycin (>128 µg/mL) and chloramphenicol (> 512 µg/mL) for all probiotics but only one was resistant to piperacillin (MIC = 32 µg/mL). PCR analysis detected erythromycin (erm(T), ermB or mefA) and fluoroquinolone (parC or gyr(A)) resistance genes in some lozenges although there were no resistant phenotypes. The dfrD, cat-TC, vatE, aadE, vanX, and aph(3")-III or ant(2")-I genes conferring resistance to trimethoprim, chloramphenicol, quinupristin/dalfopristin, vancomycin, and streptomycin, respectively, were detected in resistant probiotics. The rifampicin resistance gene rpoB was also present. We found no conjugal transfer of streptomycin resistance genes in our co-incubation experiments. Conclusion: Our study represents the first antibiotic resistance profiling of probiotics from oral lozenges, thus highlighting the health risk especially in the prevailing threat of drug resistance globally. [ABSTRACT FROM AUTHOR]

Boron fullerenes are one type of important hydrogen storage materials, however, their performance should be further improved. Since ions can provide stronger interactions with H 2 and thus better hydrogen storage capabilities, here, we explored the structure, stabilities and hydrogen storage properties of B 36 Li 6 2 + exohedral fullerene by DFT calculations. The results show that B 36 Li 6 2 + possesses thermodynamic, dynamic and chemical stabilities due to its high geometric symmetry and closed-shell electronic structure. Furthermore, eight H 2 can be adsorbed on a Li atom with ideal adsorption energies (−0.090 ∼ − 0.201eV) and the mass density of 17.2 wt%. The non-covalent interaction between H 2 and B 36 Li 6 2 + is characteris ed and identified as Van der Waals type. The energy decomposition further reveals that the induced and electrostatic interactions mainly contribute to the adsorption energies. Our results not only deepen the understanding of non-covalent interaction in physical adsorption but also suggest that B 36 Li 6 2 + is a potential hydrogen storage material. [ABSTRACT FROM AUTHOR]

With coordinated charging and discharging, electric vehicles (EVs) in smart car parks can be used as energy storage systems and a reserve against unexpected outrage. In this work, a modeling and control framework for EVs in a smart car park has been built up, which includes key factors such as the charging and discharging costs, the battery degradation cost, the driving probability, the feed-in tariff (FIT), and the vehicle-to-grid (V2G) rebates. Each EVs' charging and discharging activities are scheduled through an optimization route with the purpose to minimize the car park electricity cost. Results from comprehensive simulation studies demonstrate the potential benefits of V2G for car park systems with multiple EVs subject to vehicle and battery characteristics, FIT and policy support. [ABSTRACT FROM AUTHOR]

The Changjiang estuary and its adjacent East China Sea (ECS) have been considered as one of the most dynamic areas significantly contributing to elemental exchanges globally. The purpose of this study was to understand the alteration of microbial consortia at the interface of riverine and coastal environments in relation to environmental variations as well as their roles in biogeochemical cycling at this dynamic region. We sampled surface sediment samples at 4 stations from the estuary to coastal regions of the ECS. Along with collections of physicochemical parameters, we sequenced bacterial 16S rRNA genes of clones from each sample. Results showed a distinct transition of bacterial community from typical freshwater sediment phyla (e.g., Betaproteobacteria and Firmicutes) to those commonly inhabited in saline environments (e.g., Deltaproteobacteria and Gammaproteobacteria). The bacterial group at the transition zone characterized by high accumulation of organic matters and intense mixing of riverine and coastal waters was most diverse. Bacterial community structures at two ECS stations showed a similar pattern but contained different dominant taxa, shifting from Deltaproteobacteria-affiliated sulfate-reducing bacteria at the station closer to the shore to Gammaproteobacteria-affiliated nitrate-reducing bacteria further offshore. It suggested that the sedimentary bacterial community structure was related to salinity, sediment type, and substrate availability and composition. [ABSTRACT FROM AUTHOR]

A novel esterase gene (e25) was identified from Altererythrobacter epoxidivorans CGMCC 1.7731T by genome sequence screening. The e25 gene is 948 nucleotides in length and encodes a 315 amino acid protein (E25) with a predicted molecular mass of 33,683 Da. A phylogenetic tree revealed that E25 belongs to the hormone-sensitive lipase (HSL) family of lipolytic enzymes. An activity assay of E25 showed that it exhibited the highest catalytic efficiency when using p-nitrophenyl caproate (C6) as a substrate. The optimum pH and temperature were determined to be approximately pH 9 and 45°C, and the Km and Vmax values were 0.12 mM and 1,772 µmol/min/mg, respectively. After an incubation at 40°C for 80 min, E25 retained 75% of its basal activity. The enzyme exhibited good tolerance to metal cations, such as Ba2+, Ca2+, and Cu2+ (10 mM), but its activity was strongly inhibited by Co2+, Ni2+, Mn2+, and Zn2+. The E25 enzyme was stimulated by glycerol and retained over 60% of its basal activity in the presence of 1% Tween-80 and Triton X-100. Overall, the activity of E25 under alkaline conditions and its organic solvent and detergent tolerance indicate that E25 could be useful as a novel industrial catalyst in biotechnological applications. [ABSTRACT FROM AUTHOR]

Immature faba bean seeds of five varieties were investigated for changes in phenolic composition, antioxidant capacity and inhibitory effects on α-glucosidase and lipase at three edible stages (S1, S2 and S3). Phenolics and antioxidant capacity in seed coats were significantly higher than those in cotyledons, and the highest was found of FD18 at stage S3. While phenolic content in cotyledons decreased steadily with the harvest time delayed. Eight phenolic compounds were confirmed with epicatechin and catechin prominent and their levels showed a great variability depending on varieties, maturation stages and plant parts of faba bean seeds. Unexpectedly, the inhibitory effects of purified phenolics on α-glucosidase were even stronger than that of the positive control acarbose, and the inhibitory effects on lipase in the cotyledons declined gradually from stage S1 to S3. Significant positive correlations between phenolics from seed coats and antioxidant capacity, and phenolics from cotyledons and the enzyme inhibitory effects were observed. Overall, the immature faba bean seed, especially its seed coat, has great potential as a functional food. [ABSTRACT FROM AUTHOR]

Lycopus lucidus root, harvested from two sites at three different times, was analysed for nutritional profiles; phenolics by HPLC-MS and NMR; enzymatic activity of phenylalanine ammonia-lyase (PAL), tyrosine aminotransferase (TAT), cinnamic acid 4-hydroxylase (C4H), and polyphenol oxidase (PPO); and DNA damage protective effect. The results showed that the moisture first increased and then decreased, and the crude fat and crude fibre increased continuously during the harvesting period. Sucrose and fructose were the predominant sugars with different changing patterns. Linolelaidic, linoleic, palmitic, and stearic acids were the predominant fatty acids. No significant difference was observed of vitamin B2 accompany with an increase of vitamin C with the harvest time delayed among the three harvest times investigated. Caffeic, rosmarinic, and protocatechuic acid; rosmarinic acid methylester; protocatechualdehyde; Danshensu; 3, 4-dihydroxyphenyl caffeate; and N-trans-feruloyl tyramine were identified in L. lucidus root and their variations were discrepant in the period of harvest. There was no significant correlation between phenolics and enzymatic activity except for insoluble cell-wall-bound phenolics (ICP) and C4H, as well as protocatechualdehyde and TAT. The FP exhibited higher DNA damage protective activity than ICP. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of dried tangerine peel extract (DTPE) supplementation on the growth performance and immune and antioxidant status of broiler chicks. A total of 525 day-old, male, Arbour Acres (AA) broiler chicks were fed a basal diet (CTR) either with or without 80, 160, 240 and 480 mg DTPE/kg diet. The chicks were randomly assigned into five dietary groups for a 42-day experiment. There were seven replicates per group and 15 chicks per replicate. At 42 days of age, two birds from each cage were selected for blood sampling. The dietary DTPE supplementation linearly increased the body weight and the average daily gain (p = .03;p = .03) and quadratically increased the average daily feed intake (p = .02) during the starter period. In addition, the plasma lysozyme level in the 80 or 160 mg/kg DTPE group increased compared to the CTR group (p = .02 and .07, respectively). Chicks fed 80-mg/kg DTPE reduced the malondialdehyde concentration (p = .02) compared with birds fed the CTR diets. Moreover, the plasma glutathione peroxidase activities in the low DTPE dietary groups (80 and 160 mg/kg) were higher than in the CTR (p < .01) and 240 mg/kg DTPE group (p < .01 andp = .02, respectively). The results of the present study indicate that dietary DTPE with low supplemental dosage (≤160 mg/kg) might positively modulate the systemic antioxidative defence property of chicks. [ABSTRACT FROM AUTHOR]

Background:To evaluate the possible relationship between subclinical hypothyroidism (SCH) and metabolic syndrome (MS) and the response to clomiphene citrate (CC) stimulation in women with polycystic ovary syndrome (PCOS). Methods:One hundred and ninety-six women with PCOS were divided into two groups: (1) the SCH group with 92 patients; (2) the euthyroid (EU) group with 104 patients. Physical characteristics and metabolic parameters as well as the reaction to CC stimulating test were compared between these two groups. Results:(1) In the SCH group, significantly higher body mass index, Ferriman–Gallwey score, serum triglyceride, insulin and glucose of oral glucose tolerance test, homeostatic model assessment-insulin resistance (HOMA-IR) and significantly lower serum high-density lipoprotein cholesterol was observed in comparison with those in the EU group (p < 0.05). (2) The prevalence of CC resistance (30.4%), IR (43.5%) and MS (34.8%) in the SCH group was significantly higher than that in the EU group (p< 0.05). Conclusions:SCH was found associated with IR, MS and CC resistance in women with PCOS. PCOS patients with SCH may have a poorer treatment response to ovulation induction with CC. [ABSTRACT FROM PUBLISHER]

Inactivating mutations of the thyrotropin receptor (TSHR) gene are responsible for non-goitrogenic congenital hypothyroidism (CHNG). This study aimed to investigate mutations in theTSHRgene in 20 children with CHNG. Genomic DNA was extracted from peripheral blood leukocytes and was used for mutation screening by direct sequencing. Analyses of theTSHRgene revealed two novel variants in a 2-year-old boy with thyroid hypoplasia: a missense mutation c.1582C>T (p.R528C) and a splice-site deletion c.392+4del4. Bioinformatics analysis demonstrated that both variants are capable of causing disease. Family members of the patient with two mutations and normal controls were also recruited and investigated. Germline mutations from the proband’s family were consistent with an autosomal recessive inheritance pattern. These findings indicate that two novel inactivating mutations (p.R528C and c.392+4del4) in theTSHRgene can cause CHNG. [ABSTRACT FROM AUTHOR]

Peridinium umbonatum causes harmful algal blooms in freshwater ecosystems; however, environmental conditions that promote accelerated growth and blooming of this organism have not been resolved. Increasing global temperatures has been suggested as a possible factor for shifts in phytoplankton composition to more harmful species. Therefore, this study investigated the physiological responses of this freshwater dinoflagellate to different temperatures, a factor that will strongly be affected by future climate change scenarios. Specific growth rates of P. umbonatum were markedly lower at 10°C and 14°C than at 18°C, 25°C and 30°C, with the highest growth rate measured at 18°C. Cell mobility was significantly inhibited at 10°C and 14°C. The maximum photochemical efficiency ( Fv/ Fm) of photosystem II and maximum relative electron transport rate decreased significantly at temperatures below 14°C. However, nonphotochemical quenching significantly increased at 10°C and 14°C. Variable fluorescence at phase J increased in chlorophyll a fluorescence transients for P. umbonatum grown at 10°C and 14°C. The density of reaction centres and quantum energy flux ratios increased with increasing temperature, whereas the absorption and trapping energy flux, as well as the relative variable fluorescence intensity at the J-step, decreased with increasing temperature. These results suggest that low temperatures inhibit photosynthesis in P. umbonatum, resulting in low specific growth rates and increased cell immobility. This finding suggests that exposure to a temperature of 18°C plays an important role in the growth and cyst germination of Peridinium, implying that increasing temperature might promote dinoflagellate Peridinium blooms. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the potential effects of the 5, 10, 15, 20-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP4) on the proliferation and apoptosis of SW480 cells and the underlying mechanisms by which TMPyP4 exerted its actions.Methods: After treated with different doses of TMPyP4, cell viability was determined by MTT method, the apoptosis was observed by flow cytometry (FCM) and the expression of Wnt, GSK-3β, β-catenin and cyclinD1 was measured by RT-PCR and Western blot analysis.Results: The analysis revealed that TMPyP4 potently suppressed cell viability and induced the apoptosis of SW480 cells in a dose-dependent manner. In addition, the downregulation of Wnt, β-catenin and cyclinD1 expression levels was detected in TMPyP4-treated SW480 cells. However, followed by the block of Wnt signaling pathway using siRNA methods, the effects of TMPyP4 on proliferation and apoptosis of SW480 cells were significantly reduced.Conclusion: It indicates that the TMPyP4-inhibited proliferation and -induced apoptosis in SW480 cells was accompanied by the suppression of Wnt/β-catenin signaling pathway. Therefore, TMPyP4 may represent a potential therapeutic method for the treatment of colon carcinoma. [ABSTRACT FROM PUBLISHER]

Soil organic carbon (SOC) sequestration impacts on food security and climate change and may be affected by soil microbes in fertilized croplands. A 12-year field experiment under the rice–wheat system was used to evaluate the effect of the long-term fertilization on the SOC accumulation, culturable soil microbes, and their interaction in purple paddy soil. Results showed that varied fertilizations resulted in a significant increase of the SOC content and stock in the plow layer, as well as rise in populations of major soil microbes, including bacteria, actinomycetes, and fungi compared with no fertilization. Soil with combined application of chemical NPK fertilizer and organic amendment (pig manure or rice straw return) on average had the highest organic carbon content and stock, amounts of bacteria, actinomycetes, and fungi, which were 7.8%, 5.8%, 75.8%, 130.5%, and 16.2% higher than the NPK fertilization alone. Fertilization differentially altered populations of the functional anaerobic bacteria in paddy soil. With the combined application of chemical NPK fertilizer and organic amendment, soil displayed higher amounts of anaerobic cellulolytic bacteria, anaerobic fermentative bacteria, hydrogen-producing acetogen, methanogenic bacteria, denitrifying bacteria, and sulphate-reducing bacteria than that with the NPK fertilization alone or no fertilization. Populations of all three major soil microbes showed significantly positive correlations with the SOC content, indicating their interaction was of mutual promotion. Data suggest that the combined application of the NPK fertilizer with organic amendment especially by the rice straw return is recommended to sustain the soil biological fertility and mitigate the emission of the greenhouse gas by the SOC sequestration in purple paddy soil. [ABSTRACT FROM PUBLISHER]

Ultrasound has been successfully used to improve the performance of Mucor miehei lipase (MML) in enantioselective transesterification of N-hydroxymethyl vince lactam with vinyl valerate as acyl donor in methyl tert-butyl ether. The effects of reaction conditions have been investigated. Under the optimum conditions (ultrasound power, 175 W; temperature, 30°C; water activity, 0.22; pH, 7.0), the enzyme activity of MML was 93.7 μmol/g/min and the enantioselectivity ( E value) was 68.2. The results also indicated that the free enzyme was stable under low power ultrasound conditions. [ABSTRACT FROM AUTHOR]

By condensation of amantadine and 4-methoxysalicylaldehyde a new Schiff baseHLwas synthesized. A mixture ofHLand zinc(II) chloride in an alcoholic medium leads to [Zn(HL)2Cl2] (1). However, the same reactants gave another different complex (ZnL2) (2) in the presence of NaOH. The two complexes were characterized by IR,1H NMR, elemental analysis, molar conductance, and single-crystal X-ray diffraction. X-ray diffraction analysis reveals that complex1crystallizes in the triclinic system,P? space group; each asymmetric unit consists of one zinc(II), twoHL, and two chlorides. The tetra coordination of central zinc is attained by two chlorides and two oxygens from the Schiff base, forming a distorted tetrahedral geometry. Complex2crystallizes in the monoclinic system,P21/cspace group; each asymmetric unit consists of one zinc(II) and twoL. The tetra coordination of central zinc is attained by two nitrogens and two oxygens from the Schiff base, forming a distorted tetrahedral geometry. [ABSTRACT FROM PUBLISHER]

A 3×3 factorial arrangement with dietary non-phytate phosphorus (NPP) levels and phytase sources (3- and 6-phytase) was conducted to evaluate the effects of NPP levels, phytase sources and their possible interactions on growth performance, serum biochemical and tibia parameters of broiler chickens from hatch to 42 days of age. A total of 540 1-day-old Arbor Acres male broiler chicks were randomly allocated into nine dietary treatments, each containing 5 replicates pens with 12 birds per pen. Interaction was statistically significant in the performance till day 21 of trial, supplementation of low NPP diet decreased body weight (BW) (P<0.001), depressed average daily gain (ADG) (P<0.001) and deteriorated average daily feed intake (ADFI) (P<0.001) over day 42. During the 8-to-21-day period, even if interaction between NPP levels and phytase sources was significant (P<0.01), BW, ADG and ADFI always increased due to dietary supplementation of phytase, with source not differing. Dietary high NPP enhanced serum calcium and P concentrations on day 21 and 42 (linear contrast, P<0.01), while decreased alkaline phosphatase (AKP) activity on day 42 (linear contrast, P<0.001), and interaction was not significant. Both dietary sources of phytase decreased serum AKP activities on day 42 (P<0.001), and urea nitrogen content on day 21 (P<0.01) and 42 (P<0.001). Both phytase improved ash percentage on day 21 and P content in tibia at 21 and 42 days of age (P<0.001). The results confirmed that dietary supplementation of phytase may enhance P availability during the 8-to-21-day period. Nevertheless, no difference between the two phytase sources was observed. [ABSTRACT FROM AUTHOR]

In order to improve the efficiency of distillers' grains converting to ethanol, 13 dilute solution explosions were evaluated based on the optimization of pure water explosion. To decrease residual inhibitor content, the exploded slurry was dried at 105°C. Using a 1.1 mol/L butanone solution explosion, with the explosion temperature set at 160°C (pressure at 1.9 MPa), the residence time at 10 min, and the dried distillers' grains-to-water ratio at 1:2 (w/w), the yields of total sugar, glucose, and xylose were 86%, 89%, and 84% (w/w), respectively, and the ethanol yield was 25.3 g/100 g distillers' grains dry matter. Moreover, the eight other reagent solution explosions improved the efficiency of enzymatic hydrolysis, and of simultaneous saccharification and co-fermentation, and the residual contents of furfural, 5-hydroxymethylfurfural, and acetic acid decreased to an acceptable concentration range after detoxification by drying. The results suggested that compared with pure water explosions, the use of volatile solutions lowered the explosive temperature and improved the sugar yield. This study offers a reference for the further study of lignocellulosic materials with higher starch and hemicelluloses contents as raw materials for converting biomass to bioethanol. [ABSTRACT FROM PUBLISHER]

Previously, we developed an orthotopic xenograft model of human glioblastoma multiforme (GBM) with high EGFR expression and invasiveness in Balb/c nu/nu nude mice. Now we also developed the same orthotopic xenograft model in transgenic nude mice with green fluorescent protein (GFP) expression. The present orthotopic xenografts labeled by phycoerythrin fluorescing red showed high EGFR expression profile, and invasive behavior under a bright green-red dual-color fluorescence background. A striking advantage in the present human GBM model is that the change of tumor growth can be observed visually instead of sacrificing animals in our further antitumor therapy studies. [ABSTRACT FROM AUTHOR]

We investigated the reaction mechanism and thermochemical property of conjugated dienes or mono-olefins with nickel dithiolenes (Ni(S2C2R2)2) using density functional theory. The reactions between conjugated dienes and nickel dithiolenes are concerted reactions. The thermochemical property study shows that the introduction of electron-withdrawing groups (–CF3 or –CN) to nickel dithiolene (Ni(S2C2H2)2) not only significantly lowers the activation energy barrier but also strongly stabilises the products. The introduction of electron-donating group (–CH3) to butadiene has the same effect. So, we conclude that the reactions between nickel dithiolenes and conjugated dienes are electrophilic cycloaddition. Mono-olefins can add to nickel dithiolenes through interligand pathway, which is a two-step process or through intraligand pathway, which is a one-step process. The thermochemical property study shows that the activation enthalpy for the reaction of butadiene with Ni(S2C2(CF3)2)2 is much lower than those of C4 mono-olefins with Ni(S2C2(CF3)2)2 for both interligand addition and intraligand addition. The Gibbs free energy for the reaction of butadiene with Ni(S2C2(CF3)2)2 is also more favourable than those of C4 mono-olefins with Ni(S2C2(CF3)2)2. It is the very preferential pathway for Ni(S2C2(CF3)2)2 to bind butadiene than C4 mono-olefins. [ABSTRACT FROM PUBLISHER]

Oxidative decarboxylation of N-acyl amino acids induced by Ag+/S2O82- in formamide afforded N-acyl-N'-formyl aminal in 52-74% yields. [ABSTRACT FROM AUTHOR]

The influences induced by various terminal substituents and solvents on the reaction mechanism and chemical dynamics of complexing ethylene with Ni dithiolene are theoretically studied by using B3LYP method and Onsager model. It is shown that the reaction should be a two-step process, and the first step is the rate-determining step. We find that the rate constant of the rate-determining step becomes small when the electron-donating ability of the substituents is increased, while it becomes large when the electron-withdrawing ability of the substituents is increased. Subsequently, we consider the solvent effects on the reaction adding ethylene to the simplified hydrogen-substituted nickel dithiolene. It is found that the solvents will make slight changes to the geometries of the reactants, transition states, intermediates and products. However, the corresponding molecular dipole moments become large with the increase of the solvent polarity, which is beneficial to accelerate the reaction. Moreover, we show that, as the solvent polarity becomes large, the activation energies of the reaction decrease exponentially, while the reaction rate constants increase exponentially. These results demonstrate that in polar solvents, the reaction complexing ethylene with Ni dithiolene may become easier and faster to occur, and the product rate is improved. We believe that this research can be seen as a reference for complex and solvent selection in olefin separation process. [ABSTRACT FROM AUTHOR]

Nodal accessibility of air transportation is determined by both the location of a city and the structure of airline networks. Since the deregulation of airline industry in the United States in 1978, major carriers have increased hub‐and‐spoke operations. This study examines whether or not the increased hub‐and‐spoke operations affected nodal accessibility of air transportation during the period between 1985 and 1989. Three measures of accessibility are defined in this study: the Relative Shimbel Index (α), the First‐order Accessibility Index (β), and the Second‐order Accessibility Index (γ). Among them, the γindex is most appropriate for evaluating nodal accessibility of air transportation. The spatial pattern of changes in nodal accessibility during the study period suggests that such changes are due to the national trend in economic and demographic growth, rather than caused by the increased hub‐and‐spoke operations since deregulation. [ABSTRACT FROM PUBLISHER]

Understanding the process of decision‐making by which an individual chooses a travel mode is important for transportation researchers in constructing disaggregate travel behavior models and estimating aggregate travel demand. In order to determine if a common decision process applies to the mode‐choice behavior of the majority travellers, the data of a transportation attitudinal survey was examined in a cluster analysis. Four basic decision models were tested: the linear additive model, the conjunctive‐maximin model, the lexicographic model, and the lexicographic‐conjunctive model. The cluster analysis identified three homogeneous groups, based on their distinctive patterns of decision‐making. This suggests that different processes of decision‐making exist in travel mode‐choice behavior. Comparisons between different clustering criteria indicate that decision rules are more effective than travel attributes in differentiating travellers’ mode‐choice behavior. [ABSTRACT FROM PUBLISHER]

Since the airline deregulation of 1978, major airlines in the United States have experienced rising competition and consequently placed greater emphasis on hub‐and‐spoke operation. The locations of hub facilities thus are becoming increasingly important to determining the cost‐effectiveness of major carriers. Previous models of multiple‐hub location are limited in empirical applicability. This paper presents a model named the Hierhub model which is based on the hierarchical structure of hub‐and‐spoke networks. An important advantage of this model is that it does not require an exogenous number of hub facilities. The optimal number is derived endogenously. A modified version, the capacitated Hierhub model, can be used to expand hierarchical hub‐and‐spoke networks into more realistic multiple‐hub systems. [ABSTRACT FROM PUBLISHER]

A novel esterase gene (e25) was identified from Altererythrobacter epoxidivorans CGMCC 1.7731T by genome sequence screening. The e25 gene is 948 nucleotides in length and encodes a 315 amino acid protein (E25) with a predicted molecular mass of 33,683 Da. A phylogenetic tree revealed that E25 belongs to the hormone-sensitive lipase (HSL) family of lipolytic enzymes. An activity assay of E25 showed that it exhibited the highest catalytic efficiency when using p-nitrophenyl caproate (C6) as a substrate. The optimum pH and temperature were determined to be approximately pH 9 and 45°C, and the Km and Vmax values were 0.12 mM and 1,772 µmol/min/mg, respectively. After an incubation at 40°C for 80 min, E25 retained 75% of its basal activity. The enzyme exhibited good tolerance to metal cations, such as Ba2+, Ca2+, and Cu2+ (10 mM), but its activity was strongly inhibited by Co2+, Ni2+, Mn2+, and Zn2+. The E25 enzyme was stimulated by glycerol and retained over 60% of its basal activity in the presence of 1% Tween-80 and Triton X-100. Overall, the activity of E25 under alkaline conditions and its organic solvent and detergent tolerance indicate that E25 could be useful as a novel industrial catalyst in biotechnological applications. [ABSTRACT FROM AUTHOR]