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Metals play an essential role in biochemistry, and the use of metals for antimicrobial applications has been well studied. Biomaterials incorporating copper and silver demonstrated high antimicrobial activity while maintaining good cytocompatibility. In this overview, nanostructure processing is underscored as a method to overcome the shortcomings of conventional bioceramics. Restructuring crystalline structures at the nanoscale make it less susceptible to brittle fracture. Furthermore, the bioactivity of the material is significantly improved through nanoscale surface modifications such as coatings. The effectiveness of nanostructured biomaterials featuring copper and silver in combatting bacterial attachment and proliferation is described. Nanoscale copper-containing stainless steel achieved antimicrobial activity by disrupting bacterial metabolism and damaging bacterial membranes while providing a conducive environment for cellular proliferation. Copper-containing stainless steels can be used to prevent marine corrosion, food preservation and combat implant-related infections. It is envisaged that future antimicrobial strategies will continue to feature copper and silver nanostructured biomaterials prominently. [ABSTRACT FROM AUTHOR]

The article aimed to study intestinal absorption and pharmacokinetic characterization of three atractylenolides from low polar component of Atractylodes (LPA). LC-MS method was used to find absorbed components combined with pharmacochemistry and to determine plasma concentration combined with DAS 3.0 to calculate the PK parameters. Moreover, the everted gut sac model was used to investigate rat small intestinal absorption and transport characterization of atractylenolide I, II, III. In total, eight components were identified from the absorbed components, including two lactones (6, 7), three volatile oil (2, 3, 8), acids (1), prenylated dihydrobenzofuran derivative (4) and luteolin (5), respectively. The three atractylenolides are rapidly absorbed with Tmax as 1 h and more compatible with the two-compartment model in rats, and good linearity between Cmax and concentration. The cumulative absorption per unit area Q (ug·cm−2) of three atractylenolides were no significant difference and all linearly absorbed with different time, concentration in different intestinal segments, which indicated its absorption process was passive transport. In addition, the atractylenolides III showed most high absorption rate in all intestinal segments, and the absorption site of atractylenolides II was mainly duodenum segments. LC-MS is a systematically applicable approach for rapid screening, identification and quanlitation of absorbed components derived from atractylodes in vivo. Three atractylenolides showed similar PK characterization and passive transport through all intestinal segments. It looks more safe with less drug interaction. [ABSTRACT FROM AUTHOR]

To advance the reclamation of sewage sludge and evaluate the potential risk during sludge application, wastewater and sludge were sampled from seven secondary wastewater treatment plants seasonally in 2016 and 2017. The influent characteristics and the accumulation of eight toxic heavy metals in sludge were analyzed. According to the results, copper, chromium, nickle and zinc were the main heavy metals constraining reclamation of sewage sludge in Shanghai and they were mainly from domestic wastewater. Influent concentration, treatment process and coexisting elements had significant effects on accumulation of heavy metals in sludge. Lead concentration in sludge from AAC plants was generally higher than that from AAO plants, but for other metals the differences were insignificant or depended on the initial concentrations. Nutrients, suspended solids and coexisting heavy metals had significant effects on heavy metal accumulation in sludge when the initial concentration was controlled. [ABSTRACT FROM AUTHOR]

The method of designing an event-driven observer-based fault-tolerant controller is addressed for a state-dependent system with external disturbance and fault in this paper. An event-driven criterion is proposed to determine the updating of the controller based on the state of the Luenberger-type state-dependent observer. As a result, communication resources can be saved significantly while the desiredH∞performance is preserved. The observer error closed-loop system is rewritten as a time-varying delay system. By employing a state-dependent integral function to be a Lyapunov function candidate, the error system is proved to be asymptotically stable. The observer gain, the controller gain and the event parameters in the event condition can be co-designed and obtained in terms of solution to a set of linear matrix inequalities (LMIs). Finally, a numerical example and the tunnel diode circuit model are shown that the proposed method is effective, and the simulation results can reflect that the event-triggered scheme can lead to a larger release period than time-triggering scheme. [ABSTRACT FROM AUTHOR]

A decision correction scheme is proposed to replace the unconfident decisions in the feedback loops to mitigate the effect of error propagation in a decision feedback scheme. A likelihood based reliability ordering is also introduced to further improve the reliability of feedback stages. With a negligible additional complexity cost, the proposed scheme is able to effectively mitigate the error propagation and achieve significant performance gains. [ABSTRACT FROM AUTHOR]

CdS quantum dots sensitised solar cells were fabricated based on TiO2/carbon nanotube nanocomposite photoanodes obtained by a sol-gel process. An energy conversion efficiency increment of about three times is achieved for the solar cell with carbon nanotube content of 0·36 wt-%, and it was disclosed that the enhanced energy conversion efficiency mainly depends on the carbon nanotube content in nanocomposite photoanodes. With the carbon nanotube content increasing from 0·00 to 0·36 wt-%, the energy conversion efficiency of solar cell significantly improved from 0·38 to 1·15% because of the enhanced photogenerated electron collection efficiency and increased adsorption amount of CdS quantum dots. When the carbon nanotube content is up to 0·48 wt-%, however, the energy conversion efficiency declines to 0·75% because of a decrease of photogenerated electron collection efficiency and sensitiser adsorption. [ABSTRACT FROM AUTHOR]

Targeting drug system (TDS) or targeted drug delivery system (TDDS) is a new kind of drug delivery system which could make drug to be directly concentrated on the target site with high curative effects and low side-effects. As the quintessence of Chinese culture, traditional Chinese medicine (TCM) has a large advantage in many disease clinical treatments, especially in cancer, hypertension and many other intractable diseases owing to their low toxicity and side-effects relative to western medicine. This article reviews literatures on development of TCM-targeted preparations which were published in the past 10 years. TDS including active-targeting, passive-targeting and physical-chemical-targeting preparations were introduced through domestic and overseas literatures to reveal the unique advantages of TCM-targeting preparations in drug delivery system. In this article, we have reviewed some kinds of TCM-targeting preparations and indicated that great attention should be paid to the research on the TCM-targeting preparations. [ABSTRACT FROM AUTHOR]

NASICON (Sodium super ionic conductor) structured Li1·5Al0·5Ge1·5(PO4)3 (LAGP) solid electrolyte is synthesized through a solid state reaction. The total conductivity of the LAGP electrolyte is 7×10-5 S cm-1 with a potential window larger than 6 V. All solid state lithium batteries are fabricated using LiMn2O4 as a cathode, LAGP as an electrolyte and lithium metal as an anode. The LiMn2O4/LAGP/Li cell can deliver a capacity of about 80 mAh g-1 in the first discharge cycle and increases gradually with charge/discharge cycles, indicating that LAGP can be used as a promising electrolyte for lithium rechargeable batteries. [ABSTRACT FROM AUTHOR]

Presented herein is a study on the meshing and the integrated optimisation technique combined with configuration and mechanical behaviour for free-form reticulated shells. It focuses on the realisation of the practical layouts of meshes and improves the evaluation criteria for grid quality. For the preparation for the integrated optimisation, the bicubic quasi-uniform B-spline surface is applied to describe the free-form surface, and the energy method is introduced to smooth free-form reticulated shell through fairing factors. In order to perform optimisation automatically, a novel integrated optimisation system is established including fairing, finite element analysis (FEA) and optimisation programme modules. Based on the relationship between the fairing factors and the structural configuration, the zoned fairing factors are chosen as design variables (DVs). The FEA module is introduced to analyse and calculate the total structural strain energy of the structural components. By using the optimisation module, the optimum structural configuration can be found when the total structural strain energy reaches the minimum. Numerical results demonstrate that the proposed optimisation technique is convenient and feasible. [ABSTRACT FROM PUBLISHER]

This study investigates a core logging methodology to map rock type using thermal infrared reflectance (TIR) spectra (500–4000 cm–1or 2.5–20.0 μm) for 74 samples encompassing 11 rock types exposed in various mines of the Sudbury Basin, Canada. A continuous wavelet transform (CWT) was used to represent the original reflectance spectra as a suite of wavelets, each capturing spectral features of different scales with the low-scale components containing mineral spectral features and the high-scale components capturing the overall continuum. Classification was driven by the use of endmember spectra and the spectral angle mapper (SAM). Modelling and validation suites were developed and the mapping accuracy evaluated iteratively for random data splits. The results were compared for reflectance and wavelets of low components of power and significance. We found that the variability amongst measurements observed for varying orientation of a sample or due to variable surface roughness can be greatly minimized with the use of low-scale components, thus improving rock type classification. The average accuracy computed for the 11 rock types is highest for the low-scale component of power (72%) data as opposed to the reflectance data (55%). The highest average accuracy per rock type is obtained using the low-scale components (average value of 82%) for seven rock units that are relatively texturally homogeneous and of uniform modal mineralogy. Lower accuracy values are observed for rock units that display pronounced textural heterogeneity at the scale of observation, or variability in modal mineralogy, or are spectrally similar to other rock types. [ABSTRACT FROM PUBLISHER]

A rapid and efficient protocol for the extraction of genomic DNA from plant pathogenic fungi was developed. Key features of the protocol include the SDS-assisted lysis of fungal mycelium with inclusion of a glass bead to help break hyphal walls, followed by isopropanol precipitation of the DNA. The protocol was used to extract genomic DNA from a collection of 26 fungal species, representing many important plant pathogens. Yield of DNA ranged from 2.1-4.9 μg per 20 mg of mycelium or 0.4-0.6 μg per 20 mg of spores. The DNA was of sufficient purity to be digested by restriction enzymes, to serve as a template in the PCR-amplification of genomic fragments as large as 4.9 kb, and to be used in dot-blot hybridization for the detection of multiple- and single-copy genes. [ABSTRACT FROM AUTHOR]

This study focuses on the solid phase extraction method for the enrichment and separation of phenol from coal liquefaction oil. The phenols' separation efficiency was compared on different solid phase extraction (SPE) cartridges, and the effect of solvents with different polarity and solubility parameter on amino-bonded silica was compared for selection of optimal elution solution. The result showed that amino-bonded silica has the highest selectivity and best extraction capability due to two factors, weak anion exchange adsorption and polar attraction adsorption. [ABSTRACT FROM AUTHOR]

Coal chemical formation environment might result in different properties of hydrogen bonds in coal structure. The thermo stability, amount and types of hydrogen bond in six typical Chinese coal macerals were investigated by in situ vacuum Fourier transform infrared spectroscopy (FTIR). It was found that three types of hydrogen bond were involved in coal structure, which were OH-N, OH self associated, and OH tetrapolymer hydrogen bond. There was no correlation between the amount of three types of hydrogen bonds and extraction yield. The thermo stability of hydrogen bond in inertinite was stronger than that of vitrinite, especially the thermo stability of hydrogen bond in Pingshuo inertinite. [ABSTRACT FROM AUTHOR]

In this paper, a new data hiding scheme for halftone images by pixel swapping is proposed, and the decryption process needs no computation. The proposed scheme generates a halftone stego-image with high visual quality, and the secret can be revealed in human vision system by stacking the stego-image with another designated halftone image. The quality of the revealed secret image is better than other existing schemes. In addition, the proposed scheme can cooperate with other existing data hiding schemes for halftone images to further increase the revealed secret quality without losing the characteristic of the original stego-image. [ABSTRACT FROM AUTHOR]

A new lignan named kerinol (1) as well as 12 known compounds were isolated from the twigs of Kerria japonica (L.) DC (Rosaceae). Their structures were elucidated on the basis of spectroscopic analysis. Linariin (3) and isolinariin B (4), two major flavonoids of K. japonica, were found to exhibit significant anti-inflammatory activities in mice in vivo with an inhibitory rate of 25.5% (p < 0.001) and 13.1% (p < 0.05), respectively. [ABSTRACT FROM AUTHOR]

Biofuel cells are devices that use biocatalysts (enzymes or microbes) to convert biochemical energy directly into electrical energy. Microfluidic biofuel cells exploit the lack of active mixing at microscale dimensions to eliminate the use of proton exchange membranes that separate anolyte and catholyte streams. Simulation of this system, by solving the governing 3-D conservation equations (flow, species transport), reveals that oxygen availability limits the performance of the cathode. An exponential decay in the availability of oxygen at the cathode is observed along the length of the microchannel, indicating that increasing the number of electrode pairs reduces the overall current density. This conclusion is consistent with experimental observations. Increasing electrolyte flow rates can reduce the mass transport limitations by decreasing the diffusion boundary-layer thickness, but disparity between the flow rates of the anolyte and catholyte can induce wastage of dissolved oxygen. [ABSTRACT FROM AUTHOR]

Pyrolysis of peat could convert this material into useful fuels and valuable hydrocarbons. A study of peat pyrolysis can also serve as a useful bridge between studies of coal pyrolysis and biomass pyrolysis. Using an analytical model of pyrolysis that has previously been applied to biomass and to coal, we present here the results of applications of this model to a representative peat. The analysis suggests means of organizing and processing rate and yield data that should be useful in applications of pyrolysis for the production of fuels and chemicals. [ABSTRACT FROM AUTHOR]

Interactions of anionic polyelectrolyte (PE) with cationic monomeric (MS) and dimeric surfactants (DS) have been investigated by coarse-grained molecular dynamics (MD) simulation. A PE/surfactant mixture is observed to evolve over time into micellar complex of increasing size. The critical aggregation concentration (CAC) is qualitatively found to be much lower than the critical micellization concentration (CMC) of the free surfactant. Compared to the monomeric analog, a DS interacts more strongly with the oppositely charged polyion chain. The equilibrium complex size becomes larger with increasing surfactant concentration. Simulation results are consistent with experimental observations and reveal that the electrostatic and hydrophobic interactions play an important role in the formation of micellar complex. [ABSTRACT FROM AUTHOR]

The microphase-separation behaviors of two types of star-diblock copolymers (A) 4 (B) 4 and (AB) 4 are investigated through the dissipative particle dynamics (DPD). The simulated phase diagrams show similar ordered mesostructures as those of corresponding linear and cyclic ones, such as lamellas (LAM), perforated lamellas (PL), hexagonal (HEX) cylinders and body-centered-cubic (BCC) spheres, besides, a series of gyroid (GR) morphologies predicted by theoretical research have been identified. In the regions between the totally ordered and disordered phases, we have found some melted morphologies that can be thought as locally ordered, such as micelles (M), liquid rods (LR) and random network (RN), which have not been identified in relevant theoretical predictions. The simulated threshold for a totally ordered mesostructure to appear is higher than theoretical predictions, which can be ascribed mainly to the increasing fluctuation with finite chain length, and the star architecture can facilitate microphase separation, which is in agreement with the theoretical predictions. In addition, it is easier for the (A) n (B) n copolymers than for corresponding (AB) n ones to trigger microphase separation under the same conditions. The relations between the root-mean-square radius of gyration (RMSGR) and the composition f A in the two types of star copolymers are almost contrary, which can be attributed to the differences in their structural characteristics. [ABSTRACT FROM AUTHOR]

Polyampholytes are charged polymers containing both positively and negatively charged monomers widely used in colloid stabilization, wetting, adhesion, lubrication, etc. Due to the randomly distributed positive and negative charges on polymer backbone, polyampholyte chains have both the contraction tendency by counter charges and the stretch tendency by similar charges, which causes difficulty to develop a reliable molecular thermodynamic model. In this work, osmotic coefficients of solutions containing neutral or non-neutral polyampholyte chains with different segment sizes and charged sequences were obtained by molecular dynamics (MD) simulation, in which the Langevin equation considering both the viscous force from solvent and the stochastic force from heat-bath is used. A molecular thermodynamic model based on chemical association theory was developed where the polyampholyte molecules are modeled as positively and negatively charged hard-sphere chains with a chain length l . Those chains and counter-ions are embedded in a continuum medium. The l -particle cavity correlation function for a polyion chain is linearly approximated by a product of nearest-neighbor two-particle cavity correlation functions, density dependence of which is analytically expressed as a function of a scaling parameter from the mean-spherical approximation (MSA). It is shown that the predicted osmotic coefficients by the model agree satisfactorily with those obtained from MD simulation for neutral polyampholytes. [ABSTRACT FROM AUTHOR]

Alternating and diblock polyampholytes confined in a slit with and without an electric field have been simulated by the molecular dynamics method with a Langevin thermostat. It is shown that the slit has a strong effect on the properties of the polyampholyte. The effect is stronger when the electric field is weak, or the temperature is not too high. When a polyampholyte chain moves close to the slit wall, its radius of gyration perpendicular to the wall becomes smaller but that parallel to the wall becomes larger. Owing to the confinement of the slit, the polyampholyte chain closer to the slit wall tends to lie on the wall and becomes more flat. The width of the slit has only a little influence on the properties of solutions near the slit wall, values of several physical statistics are very close with different widths. However, when the electric field strength is strong enough in a narrow slit, the obtained properties obviously differ. [ABSTRACT FROM AUTHOR]

Co-gasification of coal and biomass is an effective way to utilize coal of low rank to alleviate problems of energy shortage and environmental pollution. In order to investigate the product distribution resulting from the co-gasification of coal and biomass in a fluidized-bed reactor, experiments were conducted at varying biomass ratios, oxygen equivalent ratios, steam/carbon ratios, and also gasification temperatures. With an increase of biomass ratio, the amount of CO and CH4increased while H2and CO2contents decreased. The amount of H2increased obviously with an increase of gasification temperature ranging from 650 to 1000°C, whereas the CO and CO2amount decreased. An increase of the steam/carbon ratio was beneficial to promote H2formation and decrease CO and hydrocarbon compounds. With an increase of the gasification temperature, the steam/carbon ratio and oxygen equivalent ratio can promote the elements with low reaction activity in biomass gasification to be useful gas compositions. [ABSTRACT FROM PUBLISHER]

The release behavior of As, Hg, Pb, and Cd in Yima during coal gasification was investigated in a fixed-bed reactor. Their modes of occurrence in coal and residues after gasification were determined by XRD and sequential chemical extraction. Pb is mostly associated with mineral matter formations in parent coal. A large proportion of Cd and As is stably associated with organic matter and sulfides. Hg is mainly that of being bound to organic matter but could be easily changed during coal gasification. It is found that bleeding ratios of As, Hg, Pb, and Cd increased with an increase of the gasification temperature, especially for Pb and As under CO2 atmosphere at high temperature. Among the toxic trace elements studied herein, Hg and Cd were found to be more volatile and enriched in the gas phase while Pb and As were mainly relegated to the solid phase during coal gasification. [ABSTRACT FROM AUTHOR]

The chemical oxygen demand (COD) and NH3-N in the coke-plant wastewater were treated by an immobilized-microbial-cell anaerobic-aerobic system. Compared with activated sludge system and immobilized nitrifiers system, the immobilized-microbial-cell anaerobic-aerobic system was more promising. When the inlet content of COD and NH3-N in the wastewater was about 1,350 mg/l and 287 mg/l, the removal efficiency of COD and NH3-N can yield up to 90.2% and 91.6%, respectively, after it was treated by the immobilized-microbial-cell anaerobic-aerobic system for 48 h. The pollutant concentration of COD and NH3-N would meet the required discharge state standard GB8978-1996 in China. Results showed that the immobilized-microbial-cell anaerobic-aerobic system had better effluent quality than the activated sludge system and immobilized nitrifiers system in terms of the simultaneous removal of COD and NH3-N in the coke-plant wastewater. [ABSTRACT FROM AUTHOR]

1. The pharmacokinetics and disposition of GDC-0879, a small molecule B-RAF kinase inhibitor, was characterized in mouse, rat, dog, and monkey. 2. In mouse and monkey, clearance (CL) of GDC-0879 was moderate (18.7-24.3 and 14.5 ± 2.1 ml min-1 kg-1, respectively), low in dog (5.84 ± 1.06 ml min-1 kg-1) and high in rat (86.9 ± 14.2 ml min-1 kg-1). The volume of distribution across species ranged from 0.49 to 1.9 l kg-1. Mean terminal half-life values ranged from 0.28 h in rats to 2.97 h in dogs. Absolute oral bioavailability ranged from 18% in dog to 65% in mouse. 3. Plasma protein binding of GDC-0879 in mouse, rat, dog, monkey, and humans ranged from 68.8% to 81.9%. 4. In dog, the major ketone metabolite (G-030748) of GDC-0879 appeared to be formation rate limited. 5. Based on assessment in dogs, the absorption of GDC-0879 appeared to be sensitive to changes in gut pH, food and salt form (solubililty), with approximately three- to four-fold change in areas under the curve (AUCs) observed. [ABSTRACT FROM AUTHOR]

Nitrogen-doped porous carbon is synthesised from mineral-rich egg yolks. Pores are produced via successive chemical etching. As anode for sodium ion batteries, the as-prepared carbon showed an initial reversible capacity of 208 mAh g−1 and a high capacity retention of 86% after 200 cycles with good rate capability. [ABSTRACT FROM AUTHOR]

In this paper, the weld appearance, microstructures and mechanical properties of electron beam welding-welded joints of SiCp/Al composite and Ti-6Al-4V were studied. The results showed that the weld appearance and mechanical properties were poor when the heat source was located at the middle of the butt joint. The weld was mainly composed of Ti3Al intermetallic compounds, but large amounts of Al4C3 brittle phase appeared at the fusion line close to the SiCp/Al composite. The weld appearance was improved by deviating the heat source towards the Ti-6Al-4V side. The microstructures of the weld changed into an α( α')+ β dual-phase structures and the amounts of Al4C3 brittle phase decreased. A well-formed joint with a tensile strength of 108·9 MPa, 60% that of the base metal, was obtained when the heat source was deviated by 0·3 mm towards the Ti-6Al-4V side. [ABSTRACT FROM AUTHOR]

The present study describes the performance of the HZSM-5 zeolite catalyst modified by Cu, Zn, Ga, La, P, Ag, and other ions for the conversion of methanol to aromatics in a fixed-bed reactor, and the influences of the system pressure and temperature on methanol aromatization are in discussion. The results show that the optimum single ion for the modification of catalyst was Zn or Cu. The optimum combined ions were Zn and Ga. The yield of aromatics could reach up to 66.6% on the catalyst modified with Ga2% and Zn10%. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy (XAS) is a versatile technique for studying the electronic structure and/or the local geometry of matter, and time-resolved XAS has been developed into a powerful tool for studying the dynamics of materials [1, 2]. The temporal resolution of this technique is usually determined by the X-ray pulse duration in pump and probe geometries. Although this technique has been developed in the synchrotron environment and takes advantage of existing X-ray beamlines, the study of ultrafast dynamics on time scales on the order of a picosecond or faster is limited because typical pulse durations from third-generation light sources is on the order of tens of picoseconds. In addition, XAS typically requires the integration of a large number of X-ray pulses to get quality data. These features make it difficult to apply this technique to research areas in which samples undergo irreversible processes. [ABSTRACT FROM AUTHOR]

In a core displacement experiment, simulated oil, formation water, injected water, and distillated water were used as fluids to measure and analyze the threshold pressure gradient (TPG) for both a single- and two-phase fluid flow. A certain Chinese oil field core sample was used, which represents a typical ultra-low permeability reservoir: “block 119.” The study indicates that different types of fluids give a different TPG versus permeability power function, with index equal to approximately -1. The study also indicates that, due to the capillary pressure and the Jamin effect, the TPG for the two-phase oil and water is greater than that for the single-phase flow. By combining laboratory and field data, the effect of the TPG in the development of the ultra-low permeability reservoirs can be explained. [ABSTRACT FROM AUTHOR]

An explicit carrier-based compact model for the nanowire surrounding-gate (SRG) Metal-oxide-Semiconductor Field Effect Transistor (MOSFET) simulation is presented in this paper in the formulation of an accurate yet analytic approximate solution of the carrier concentration. It is shown that the analytic approximation solution of the carrier concentration has been derived from a simplified Taylor expansion of the exact solution of the Poisson's equation of the SRG MOSFETs, instead to resorting to the Newton-Raphson numerical iterative calculation. This analytic approximation also gives accurate dependences of the carrier concentration on the geometry structures and the bias, compared with the Newton-Raphson numerical results. Further, the obtained analytic approximation solution is combined with the Pao-Pah current formulation to get an explicit physics based current-voltage model of the SRG MOSFETs, and the model predictions also show in a good agreement with the result of the Newton-Raphson iterative. [ABSTRACT FROM AUTHOR]

Shape descriptors used in 3D QSAR studies naturally take into account chirality; however, for flexible and structurally diverse molecules such studies require extensive conformational searching and alignment. QSAR modeling studies of two datasets of fragrance compounds with complex stereochemistry using simple alignment-free chirality sensitive descriptors developed in our laboratories are presented. In the first investigation, 44 α-campholenic derivatives with sandalwood odor were represented as derivatives of several common structural templates with substituents numbered according to their relative spatial positions in the molecules. Both molecular and substituent descriptors were used as independent variables in MLR calculations, and the best model was characterized by the training set q 2 of 0.79 and external test set r 2 of 0.95. In the second study, several types of chirality descriptors were employed in combinatorial QSAR modeling of 98 ambergris fragrance compounds. Among 28 possible combinations of seven types of descriptors and four statistical modeling techniques, k nearest neighbor classification with CoMFA descriptors was initially found to generate the best models with the internal and external accuracies of 76 and 89%, respectively. The same dataset was then studied using novel atom pair chirality descriptors (cAP). The cAP are based on a modified definition of the atomic chirality, in which the seniority of the substituents is defined by their relative partial charge values: higher values correspond to higher seniorities. The resulting models were found to have higher predictive power than those developed with CoMFA descriptors; the best model was characterized by the internal and external accuracies of 82 and 94%, respectively. The success of modeling studies using simple alignment free chirality descriptors discussed in this paper suggests that they should be applied broadly to QSAR studies of many datasets when compound stereochemistry plays an important role in defining their activity. [ABSTRACT FROM AUTHOR]

Poly(ethylene terephthalate) (PET) microfiber was in-situ formed by compounding PET with polyethylene (PE) through a single screw extruder of a Haake rheometer system, where a rod die with comparatively smaller diameter (2.1 mm) was used, and the extrudate was drawn in a certain drawing ratio (3.1:1) and quickly cooled in cold water. Subsequently, the in-situ PET/PE composite was injection molded into specimens at temperatures that were lower than the melting temperature of the PET to keep the original shape of the PET fibers. The result from morphology observations of the composite showed that when the die diameter of the extruder is 2.1 mm and the drawing ratio of the extrudate is 3.1:1, PET was more or less changed into microfibers. The PET almost changed into fibers when the concentration was 15 wt%; concentrations below and above which decreased the fiber content. For the PET/PE blend prepared by conventional mixing technology, the dispersed PET formed spheres and no microfibrilar structure were found. The reinforcing effect of the PET fibers on the corresponding composite was significant at 15 wt% PET concentration observed from the correlation between the PET content and the tensile properties of the PET/PE in-situ composite. Besides, in general, the tensile strength and modulus of the composite increased with the PET concentration, and was higher than the conventional PET/PE blend without microfibers. [ABSTRACT FROM AUTHOR]