Search

One of the key problems in radio frequency identification (RFID) is security and privacy. Many RFID authentication protocols have been proposed to preserve security and privacy of the system. Nevertheless, most of these protocols are analyzed and it is shown that they cannot provide security against some RFID attacks. Strong authentication and strong integrity (SASI) is the first ultra-lightweight authentication protocol introduced rotation shift operation and RFID authentication protocol with permutation (RAPP) is a new ultra-lightweight authentication protocol with permutation. In this paper, we give the security analysis on these two protocols. An active attack is presented on RAPP, and using the property of the left rotation and permutation operations, we can deduce the relationship of bits of random number or secret keys at different positions, thus obtain all the secrets shared by the reader and the tag. A passive full-disclosure attack is proposed on SASI. Using SASI's construction weakness, our attack can reveal all the secrets shared by the reader and tag by eavesdropping about 48 rounds of the authentication messages. [ABSTRACT FROM AUTHOR]

We report on ordered nanoporous films exhibiting a unique magneto-plasmon based response, fabricated by nanosphere-assisted physical deposition. This work focuses on multi-layer Ag/CoFeB/Ag films as examples of such structures. Their microstructure dependent magnetic properties, localized surface plasmon resonance (LSPR) and magneto-optical Kerr effect were investigated. The observed effects of nanopores and Ag layers on the magnetic properties indicate the synergistic interaction between nanopores and Ag layers leading to an enhancement of the ferromagnetic character of the CoFeB film. LSPR spectra reveal that the introduction of Ag layers enhances the light transmission in the nanoporous CoFeB films (having pore sizes exceeding the wavelength of light) due to an enhanced interaction of light with surface plasmons. Periodic nanoporous Ag/CoFeB/Ag films covered by Ag capped nanospheres show a much larger extinction than uncovered nanoporous Ag/CoFeB/Ag films. The correlation between the magneto-optical Kerr effect and the nanostructures suggests a field-tunable Kerr effect owing to the magneto-electric coupling between the magnetic layer and the Ag layers, which is enhanced by the nanopores. These hybrid nanostructures are expected to offer potential applications in photovoltaic cells and for magneto-optic sensors. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a poly( N-isopropylacrylamide) (PNIPAm) through the polymerization of N-isopropylacrylamide in distilled water with azodiisobutyronitrile as the initiator and a bisadenine-functionalized poly(ethylene oxide) (A-PEO-A) from the reaction of adenine with a difunctionalized toluenesulfonyl-PEO. When blended together in distilled water, PNIPAm and A-PEO-A formed supramolecular aggregates stabilized through complementary multiple hydrogen bonds between the amide groups of PNIPAm and the adenine units of A-PEO-A. Agrawal integral equation and rheometry revealed the rheological kinetics of supramolecular assemblies, which were influenced significantly by the spherical micelles, large associated aggregates of spherical micelles, network structures, and toroid structures formed in aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, we prepared exfoliated nanocomposites from polyvinyl acetate (PVAc) and organic montmorillonite (OMMT) through different synthesis processes. OMMT was exfoliated into layers or sheets of nanoparticles. They dispersed in PVAc matrix randomly. The synthesis processes influenced the dispersion and apparent viscosity significantly. PVAc and PVAc-OMMT both were pseudo-plastic Non-Newtonian fluids and had the normal stress effect (or Weissenberg effect) from pole-climbing phenomenon. By analyzing the apparent viscosity using power-law function equation, Newtonian fluid flow equation, and Cross-Williamson model viscous equation, the synthesis processes and OMMT had a combined effect on the rheology of PVAc and PVAc-OMMT. With the change of synthesis processes and the increase of OMMT content in synthesis system, the calculated molecular weight of PVAc-OMMT increased. [ABSTRACT FROM AUTHOR]

Post-operative cognitive dysfunction (POCD) is associated with increased cost of care, morbidity, and mortality. However, its pathogenesis remains largely to be determined. Specifically, it is unknown why elderly patients are more likely to develop POCD and whether POCD is dependent on general anesthesia. We therefore set out to investigate the effects of peripheral surgery on the cognition and Alzheimer-related neuropathology in mice with different ages. Abdominal surgery under local anesthesia was established in the mice. The surgery induced post-operative elevation in brain β-amyloid (Aβ) levels and cognitive impairment in the 18 month-old wild-type and 9 month-old Alzheimer's disease transgenic mice, but not the 9 month-old wild-type mice. The Aβ accumulation likely resulted from elevation of beta-site amyloid precursor protein cleaving enzyme and phosphorylated eukaryotic translation initiation factor 2α. c-Secretase inhibitor compound E ameliorated the surgery-induced brain Aβ accumulation and cognitive impairment in the 18 month-old mice. These data suggested that the peripheral surgery was able to induce cognitive impairment independent of general anesthesia, and that the combination of peripheral surgery with aging- or Alzheimer gene mutation-associated Aβ accumulation was needed for the POCD to occur. These findings would likely promote more research to investigate the pathogenesis of POCD. [ABSTRACT FROM AUTHOR]

Amorphous carbon is one of the most lubricious materials known, but the mechanism is not well understood. It is counterintuitive that such a strong covalent solid could exhibit exceptional lubricity. A prevailing view is that lubricity of amorphous carbon results from chemical passivation of dangling bonds on surfaces. Here we show instead that lubricity arises from shear induced strain localization, which, instead of homogeneous deformation, dominates the shearing process. Shear localization is characterized by covalent bond reorientation, phase transformation and structural ordering preferentially in a localized region, namely tribolayer, resulting in shear weakening. We further demonstrate an anomalous pressure induced transition from stick-slip friction to continuous sliding with ultralow friction, due to gradual clustering and layering of graphitic sheets in the tribolayer. The proposed shear localization mechanism sheds light on the mechanism of superlubricity, and would enrich our understanding of lubrication mechanism of a wide variety of amorphous materials. [ABSTRACT FROM AUTHOR]

In this study, we presented the use of polyurethane, ethylene-vinyl acetate hotmelt, and nano hexagonal boron nitride particles to prepare high surface adhesion polymer fibers via an elertrospinning method. The shear strength, dynamic tensile properties, and surface morphology have been investigated. These polymer fibers were found to have high shear strength, high tensile stress, and high tensile strain, which may have a good potential application in the matrix materials for thermal interface materials. Polymer fibers with and without nano hexagonal boron nitride particles showed the shear strength of 6.52 MPa and 5.44 MPa respectively on being heated up at 150°C for 45 min. [ABSTRACT FROM AUTHOR]

Magnetostriction of ferromagnetic materials describes the change of their shape or dimension in response to the reorientation of magnetization under the influence of external magnetic field. Fe100-xGax binary alloys (Galfenol) have large magnetostriction and excellent ductility; and they are very promising rare-earth free materials for applications in sensors, actuators, energy-harvesters and spintronic devices. Here we report results of large-scale ab initio molecular dynamics (AIMD) simulations for Galfenol, especially regarding the mechanism that leads to the sudden drop of tetragonal magnetostriction at x ~ 19, a long-standing puzzle for the community. Based on rigid band analysis, we propose possible ways to further optimize the performance of Galfenol for device applications. For example, we found that the substitution of a small amount of Cu for Ga (1.6%) in certain configuration may double the magnetostriction of Galfenol. [ABSTRACT FROM AUTHOR]

We have designed a novel hybrid nanostructure by coating Fe2O3 nanoparticles with multi-walled carbon nanotubes to enhance the lithium storage capability of Fe2O3. The strategy to prepare Fe2O3@MWCNTs involves the synthesis of Fe nanoparticles wrapped in MWCNTs, followed by the oxidation of Fe nanoparticles under carbon dioxide. When used as the anode in a Li-ion battery, this hybrid material (70.32 wt% carbon nanotubes, 29.68 wt% Fe2O3) showed a reversible discharge capacity of 515 mAhg-1 after 50 cycles at a density of 100 mAg-1 and the capacity based on Fe2O3 nanoparticles was calculated as 1147 mAhg-1, Three factors are responsibile for the superior performance: (1) The hollow interiors of MWCNTs provide enough spaces for the accommodation of large volume expansion of inner Fe2O3 nanoparticles, which can improving the stability of electrode; (2) The MWCNTs increase the overall conductivity of the anode; (3) A stable solid electrolyte interface film formed on the surface of MWCNTs may reduce capacity fading. [ABSTRACT FROM AUTHOR]

In this study, an exfoliated montmorillonite was prepared through click chemistry from a singly azido-functionalized polyhedral oligomeric silsesquioxane derivative and a montmorillonite intercalated with propargyldimethylstearylammonium bromide. This exfoliated montmorillonite was then introduced into a benzoxazine matrix-prepared from paraformaldehyde, aniline, and phenol-to form polymer/exfoliated clay nanocomposites. Thermogravimetric analysis revealed that the pyrolysis kinetics had a close relationship with the structure of montmorillonite, the assembly process, the anchoring effect, the compatibility of the polymer and intercalator, and the char yield. The polymer/exfoliated clay nanocomposites had a same mechanism function, and the kinetic compensation effect equations revealed the pyrolysis essences. [ABSTRACT FROM AUTHOR]

Preferential CO oxidation (PROX) was investigated by using dealloyed nanoporous gold (NPG) catalyst under ambient conditions. Systematic investigations were carried out to characterize its catalytic performance by varying reaction parameters such as temperature and co-existence of CO2 and H2O, which revealed that NPG was a highly active and selective catalyst for PROX, especially at low temperature. At 20°C, the exit CO concentration could be reduced to less than 2 ppm with a turnover frequency of 4.1 ×10-2 s-1 at a space velocity of 120,000 mL h-1 g-1 cat. and its high activity could retain for more than 24 hours. The presence of residual Ag species in the structure did not seem to improve the intrinsic activity of NPG for PROX; however, they contributed to the stabilization of the NPG structure and apparent catalytic activity. These results indicated that NPG might be readily applicable for hydrogen purification in fuel cell applications. [ABSTRACT FROM AUTHOR]

Invisibility devices have attracted considerable attentions in the last decade. In addition to invisibility cloaks, unidirectional invisibility systems such as carpet-like cloaks and parity-time symmetric structures are also inspiring some specific researching interests due to their relatively simplifying design. However, unidirectional invisibility systems worked generally in just one certain illumination direction. Here, based on time-reversal principle, we present the design and fabrication of a kind of all-dielectric device that could directionally cancel objects and create illusions as the illuminating light was from different directions. Our devices were experimentally realized through holographic technology and could work for macroscopic objects with any reasonable size at visible wavelengths, and hence may take directional invisibility technology a big step towards interesting applications ranging from magic camouflaging, directional detection to super-resolution biomedical imaging. [ABSTRACT FROM AUTHOR]

In this study, a matrix resin containing a functional epoxy, a reactive diluent, a silane-coupling agent, and a curing agent was used to fabricate three modal electrically conductive adhesives (ECAs) with micron silver flakes, nano silver spheres, and treated single-wall carbon nanotubes (CNT). Results showed that too many micron silver flakes reduced the bulk resistivity and adhesion strength of uni-modal ECAs (matrix resin and micron silver flakes). As the nano silver spheres increased, the bulk resistivity of bi-modal ECAs (matrix resin, micron silver flakes, and nano silver spheres) firstly decreased, and then increased again. The adhesion strength decreased also. The bulk resistivity and adhesion strength of tri-modal ECAs (matrix resin, micron silver flakes, nano silver spheres, and treated CNT) both were reduced by the treated CNT greatly. These ECAs could be cured at 120°C or any higher temperature than this with different curing time. They all had high temperature stability with a pyrolysis temperature above 350°C and a glass transition temperature around 180°C. [ABSTRACT FROM AUTHOR]

In this study, an exfoliated montmorillonite was introduced into a benzoxazine matrix-prepared from paraformaldehyde, aniline, and phenol-to form polymer/exfoliated clay nanocomposites. Wide-angle X-ray diffraction, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and contact angle measurements revealed the structures and thermal and mechanical properties of these polybenzoxazine/clay nanocomposites; the montmorillonite was exfoliated into nanoparticles (single sheets or layers) that were dispersed in the polybenzoxazine matrix. The incorporation of the exfoliated montmorillonite improved the polymer's glass transition and thermal decomposition temperatures, mechanical properties, and surface hydrophobicity. [ABSTRACT FROM AUTHOR]

One-year-old potted clone plants of four willow species (Salix matsudana × alba, S. babylonica, S. psammophila and S. cheilophila) were cultivated and irrigated with saline solutions of different concentrations, while their electrical impedance spectroscopy (EIS) parameters and other physical parameters were monitored. The results indicate i) that under salt stress, height and basal diameter of all species are inhibited, and ii) that relative conductivity of cellular exudates increases while intracellular resistance (ri) and extracelluar resistance (re) drop. Both ri and re were positively correlated with height growth and basal diameter while they were significantly and negatively correlated with electric conductivity. The concentration of Na+ in the shoots of willows was negatively correlated with both ri and re, whereas the concentration of K+ in the shoots was positively correlated with both ri and re. Hence, electrical impedance spectroscopy is a reliable tool for evaluating the capacity of willow species for tolerance to saline soils, with ri as the most accurate parameter. [ABSTRACT FROM AUTHOR]

High formaldehyde emission and poor water resistance are two main disadvantages of urea formaldehyde (UF) resin. For that reason, a novel polyvinyl acetate (PVAc) type emulsion curing agent was developed in this paper. PVAc type emulsions, including PVAc, the co-polymer of PVAc and N-hydroxymethyl acrylamide (PVAc-NMA), and the ternary co-polymer of PVAc, NMA, and urea (PVAc-NMA-urea), were the main components. Water, aluminum chloride, ammonium dihydrogen phosphate, polypropylene glycol, silicone oil, and urea were the other components. Under heating, aluminum chloride and ammonium dihydrogen phosphate often underwent thermal decomposition and hydrolysis in solution, produce free acid to cure UF resin, so the curing agent could enhance the curing rate, and then shorten the curing time. In this curing agent, ammonium dihydrogen phosphate and urea worked as formaldehyde removers and reacted with free formaldehyde in UF resin, thus the formaldehyde emission exuded from the plywood could be effectively limited and reduced. The bonding strength of plywood was not improved very much, especially the dry bonding strength, but the wet bonding strength was little enhanced for the active hydroxymethyl group contained in PVAc-NMA and PVAc-NMA-urea underwent a self-cross-linking reaction to improve the bonding strength and adhesion force to the bonded substrate. More importantly, the results from the industrial production experiments were shown to be very good. [ABSTRACT FROM AUTHOR]

The information used to build proteins is stored in the genetic material of every organism. In nature, ribosomes use 20 native amino acids to synthesize proteins in most circumstances. However, laboratory efforts to expand the genetic repertoire of living cells and organisms have successfully encoded more than 80 nonnative amino acids in E. coli, yeast, and other eukaryotic systems. The selectivity, fidelity, and site-specificity provided by the technology have enabled unprecedented flexibility in manipulating protein sequences and functions in cells. Various biophysical probes can be chemically conjugated or directly incorporated at specific residues in proteins, and corresponding analytical techniques can then be used to answer diverse biological questions. This review summarizes the methodology of genetic code expansion and its recent progress, and discusses the applications of commonly used analytical methods. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Epoxy molding compound (EMC) has been widely used as a main material for encapsulation and protection of semiconductor packages because of its low cost, high moisture resistance, high heat resistance, and good mechanical performance. Due to the extensive application of lead-free solder in place of Sn-Pb, soldering temperature is higher than before; this demands that EMC, which is usually used for lead-free solder, should have extremely low thermal stress and excellent stability at elevated temperatures. In this work, 1,3-propanediol bis(4-aminobenzoate) (PBA) was added to an EMC product to form a novel epoxy molding compound (FEMC). PBA had very limited effect on the process feasibility of EMC, and caused reduction of the storage modulus by 40% to 50% at high temperatures and reduction of the glass-transition temperature by more than 10°C, which are very helpful to reduce thermal stress buildup during high-temperature soldering processes. The increases of the tab pull force of copper- and silver-plated lead frames within EMC due to PBA were up to 58% and 117%, respectively. With increasing PBA content in the EMC, water absorption increased in a linear fashion, so the amount of PBA added to the EMC should be limited, preferably to not more than 1%. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the clinical significance of real-time contrast-enhanced ultrasonography in the differential diagnosis of breast tumor. Fifty-seven breast tumor patients with 63 lesions were studied. Among the lesions, 34 are malignant and 29 are benign. A Philips iU-22 ultrasound scanner with L12-5 probe was used. Bolus SonoVue was injected via antecubital vein. Dynamic imaging was stored and analyzed with QLAB software. Parameters including initial time of perfusion (ITP), time to peak (TTP), peak intensity (PI), the enhancement pattern and the wash out pattern (WP) of contrast agent were observed. Results showed that about 85.3% of the malignant lesions showed heterogeneous enhancement and 79.3% of the benign ones showed homogeneous enhancement. The persistence time of the contrast agents was clearly longer inside the malignant lesion than inside the benign ones. Nevertheless, there were no significant differences in the value as ITP and TTP between the malignant and the benign lesions, while the PI value of the malignant lesions was significantly higher than the benign lesions. This study suggested that real-time contrast-enhanced ultrasonography is helpful to the differential diagnosis of breast tumors; however, the WP of the contrast agent inside the lesion also seems to be an important factor. [ABSTRACT FROM AUTHOR]

In this paper, a strongly nonlinear coupled elliptic-parabolic system modelling a class of engineering problems with heat effect is studied. Existence of a weak solution is first established by Schauder fixed point theorem, where the coupled functions σ(s), k(s) are assumed to be bounded. The uniqueness of the solution is obtained by applying Meyers' theorem and assuming that σ(s), k(s) are Lipschitz continuous. The regularity of the solution is then analyzed in dimension d ≤ 2 under the assumptions on σ(s), k(s) ∈ C²(ℝ) and the boundedness of their derivatives of second order. Finally, the blow-up phenomena of the system are studied. [ABSTRACT FROM AUTHOR]

A gradient structure was synthesized on the surface of Zr55Al10Ni5Cu30 alloy with high glass-forming ability by laser surface melting (LSM). Along the laser incident direction, the surface remelted alloy exhibits gradient microstructure distributed in the sequence of amorphous structure, nanocrystal- reinforced amorphous matrix composite (transitional layer A), dendrites--amorphous phase composite (transitional layer B), and crystalline phases from the top surface to the substrate. The formation mechanism of this gradient structure is discussed based on the experimental results of the microstructure together with the finite volume simulation of the process of LSM treatment. The friction coefficient of the transitional layer A is ∼ 2.5 times lower than those of the other layers under the same sliding friction condition, and possible reasons for this phenomenon are discussed in connection with the rollingmotion and material transfer mechanism. The transitional layer B exhibits the best wear resistance among all the structures studied here, which is related to the optimized ratio of microhardness to reduced Young's modulus (H/Er). [ABSTRACT FROM AUTHOR]

The new in situ seed baiting method using seed packets to assess germination of orchid species within soil provides a means of locating, collecting, and identifying specific fungi that are involved in the lifecycle of orchids in the wild and investigating their relationship with the orchids under natural field conditions. Two isolates (SHH44, SHH53) originating from the seedlings found in the seeds packets in situ were demonstrated to support seed germination and seedling development (in vitro) of two endangered Chinese endemic herbs, Dendrobium officinale and Dendrobium nobile (Orchidaceae). Advanced protocorm development (Stage 3 and greater) in this study of these species of Dendrobium only occurred under the 12/12 h L/D photo-period indicated that illumination may play an important role in seedling recruitment of terrestrial orchid species in their natural environment. The information provided in this study may prove invaluable in the conservation of D. officinale and D. nobile and congener species in China, especially given their rare status. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to estimate publics' willingness to pay (WTP) for environment conservation and analyze factors influencing WTP. A questionnaire survey based on the contingent valuation method (CVM) was carried out at Kanas Nature Reserve, Xinjiang, China. Seventy-three percent of the 412 respondents were willing to pay at different levels, and the mean WTP value was RMB 54.60 ($8.03). The results of this survey struck an optimistic note that publics were willing to contribute to improve environmental quality. Logistic regression analysis was employed to compare the characteristics of those who were and were not willing to pay. Chi-square tests were administered to identify the relationships between various explanatory factors and WTP. Conclusions and implications of the empirical study can be provided to policy makers and site managers. In a wider sense, the findings of this study should make a good contribution to the literature related to WTP for environment conservation of natural attractions. [ABSTRACT FROM AUTHOR]

Laser consolidation (LC) developed by National Research Council's Industrial Materials Institute (NRC-IMI-London) since mid-1990s, is a laser cladding based rapid manufacturing and material additive process that could fabricate a 'net-shape' functional metallic shape through a 'layer-upon-layer' deposition directly from a computer aided design model without using molds or dies. In order to evaluate the LC processability of different materials, some representative nickel-based superalloys (IN-625, IN-718, IN-738, and Waspaloy), stainless steels (austenitic SS316L and martensitic SS420), and lightweight alloys (Ti-6Al-4V titanium alloy and Al-4047 aluminum alloy) have been investigated. Like other laser cladding based processes, due to process-induced rapid directional solidification, the LC alloys have demonstrated certain unique morphological characteristics. Moreover, the 'as-consolidated' LC alloys, in nature, are in the 'as-quenched' state, and some precipitation processes from their matrices, which are sometimes critical to the development of mechanical performance of the materials, could be effectively suppressed or retarded. Post-heat treatments, therefore, could necessarily facilitate the process of achieving their required operational microstructures. In this article, a comprehensive investigation was performed including metallurgical soundness and process-induced morphological characteristics of the LC materials, and microstructure development brought by post-LC heat treatments using optical microscope, scanning electron microscope, and X-ray diffraction. The implications on the mechanical performance of the LC materials were discussed as well in order to provide essential information for potential industrial applications of the LC materials. [ABSTRACT FROM AUTHOR]

Glycine in the hippocampus can exert its effect on both synaptic NMDA receptors (NMDARs) and extrasynaptic functional glycine receptors (GlyRs) via distinct binding sites. Previous studies have reported that glycine induces long-term potentiation (LTP) through the activation of synaptic NMDARs. However, little is known about the potential role of the activated GlyRs that are largely located in extrasynaptic regions. We report here that relatively high levels of glycine achieved either by exogenous glycine application or by the elevation of endogenous glycine accumulation with an antagonist of the glycine transporter induced long-term depression (LTD) of excitatory postsynaptic currents (EPSCs) in hippocampal CA1 pyramidal neurons. The co-application of glycine with the selective GlyR antagonist strychnine changed glycine-induced LTD (Gly-LTD) to LTP. Blocking the postsynaptic GlyR-gated net chloride flux by manipulating intracellular chloride concentrations failed to elicit any changes in EPSCs. These results suggest that GlyRs are involved in Gly-LTD. Furthermore, this new form of chemical LTD was accompanied by the internalization of postsynaptic AMPA receptors and required the activation of NMDARs. Therefore, our present findings reveal an important function of GlyR activation and modulation in gating the direction of synaptic plasticity. [ABSTRACT FROM AUTHOR]

The distribution, size, and appearance of Peyer's patches vary according to species. In order to determine the anatomical characteristics of Peyer's patches in small intestine of Bactrian camel, and age-related changes in the number of Peyer's patches, 40 Bactrian camels of the following four age groups were studied: young (0.5-2 years), pubertal (3-5 years), middle-aged (6-16 years), and old (17-20 years). The exact number of Peyer's patches was recorded, and the appearance of Peyer's patches was described in detail. The results indicated that Peyer's patches of Bactrian camels not only have a particular anatomical location and distinct appearance but also change with age. They were distributed in the whole small intestine and there were four distinct types of Peyer's patches: nodular, faviform, cup-shaped, and cystic form Peyer's patches. However, the nodular and cystic form Peyer's patches are specific to Bactrian camel, which have not been found in other animals including Dromedary camel. In addition, the distribution density of Peyer's patches in ileum was the maximum, then was jejunum and duodenum. Further statistical analysis showed that the number of Peyer's patches was altered with age. The number peaked in 5-year-old camels and declined subsequently with age. However, there was little change in the size of Peyer's patches in different age groups; no age-related macroscopic variations in the shape or size of the Peyer's patches were found. Results obtained from this study provide the basic information to further study on the gastrointestinal mucosal immunity of Bactrian camel. [ABSTRACT FROM AUTHOR]

The pluronic block copolymers are able to enhance the ultrasound-induced gene delivery in vitro. In the present study, the effects of pluronics on the efficiency of gene transfer into skeletal muscle in vivo under sonoporation were investigated. Plasmid DNA encoding green fluorescent protein (GFP) in combination with three different pluronics, F127, L61, and P85, was injected into the tibialis anterior (TA) muscle of mice with and without adjunct ultrasound (1 MHz, 3 W/cm 1 min, 20% duty cycle). Mice were killed 1 week after injection. The TA muscles were removed and snap frozen immediately in isopentane cooled by liquid nitrogen and sections of 7 μm thick were cut. Transfection efficiency was assessed by counting the number of GFP-positive fibers under fluorescence microscopy, and tissue damage by hematoxylin and eosin staining. The results suggested that all three pluronics significantly enhanced transgene expression in skeletal muscle ( P < 0.01), especially the P85 showed significantly higher efficiency than the other two pluronics ( P < 0.05). Ultrasound synergistically enhanced the gene delivery efficiency with P85 ( P < 0.01), but was unable to do so with F127 and L61 groups. In short, P85 displays significantly synergistic effect with ultrasound for enhancing plasmid DNA transduction in skeletal muscle of mice in vivo. [ABSTRACT FROM AUTHOR]

The northeastern margin of the Qinghai-Tibetan Plateau is typically a vulnerable eco-environment where an overload of alpine meadows and serious soil degeneration have led to vulnerability to natural disasters. Consequently, this vulnerable eco-environment does not allow for rapid socioeconomic development, resulting in weak potential for sustainable development. The northeastern margin of the Qinghai-Tibetan Plateau in China is used for this case study, which sets up 17 impact factors of eco-environment vulnerability (EEV) to assess the indexes, including natural impact factors, economic impact factors and social impact factors. Subsequently, the study uses an analytic hierarchy process to endow index weights and proposes an assessment model of $$ G = 1 - \sum\nolimits_{i = 1}^{n} {{{P_{i} \cdot W_{i} } /{( {\max \sum\nolimits_{i = 1}^{n} {P_{i} \cdot W_{i} } + \min \sum\nolimits_{i = 1}^{n} {P_{i} \cdot W_{i} } } )}}} $$ to analyze and assess the dynamic changes in the EEV of the study area from 1987-2008. Finally, the correlation of the EEV and 17 impact factors is analyzed. [ABSTRACT FROM AUTHOR]

In the study, a fast and selective method based on magnetic separation has been developed for the extraction of nicotine from human plasma using magnetic strong cation exchange (MSCX) resins as adsorbent. MSCX resins were prepared using hydrophobic FeO magnetite as magnetically susceptible component, styrene and acrylic acid as polymeric matrix components, and acetyl sulfonate as the sulfonation agent. The extraction procedure was carried out in a single step by stirring the mixture of diluted plasma sample and MSCX resins in the vortex for 5 min. Then, the resins with adsorbed nicotine were separated from the sample matrix by applying an appropriate magnetic field. Main factors affecting the extraction of nicotine such as the amount of MSCX resins, pH value of the extraction solvent, extraction time, and washing and eluting conditions were optimized. The nicotine eluted from the resins was determined by liquid chromatography-tandem mass spectrometry. The calibration curve obtained by analyzing matrix-matched standards shows excellent linear relationship ( r = 0.9998) in the concentration range of 10-2,500 ng mL. The limit of detection and quantification obtained are 2.9 and 9.7 ng mL, respectively. The relative standard deviations of intra- and inter-day obtained are in the range of 1.9-6.9% and 2.5-7.8% with the recoveries ranging from 78.7% to 99.1%. The proposed method was successfully applied to determine nicotine in human plasma phlebotomized from ten male smokers. Nicotine was detectable with the contents ranging from 44.4 to 221.9 ng mL in five samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Various lithographic approaches have been developed to generate patterns on flat and non-flat surfaces. However, it still remains a challenge to produce patterns on irregular surfaces, such as on the curved tip of a glass micropipette. To overcome this challenge, we have developed two new approaches in this work, and explored the possibility of applying them to generate Au microlines on the outer surfaces of glass micropipettes. A glass micropipette includes a straight tube and a curved tip. In either approach, the outer surface of the glass micropipette was first thermally coated with a thin Au film. A photoresist (PR)-coated membrane was then pushed against this glass micropipette when the PR was still wet. During the contact, part of the PR was transferred from the membrane to the micropipette. After the membrane was removed, a continuous PR line was left on the outer surface of the glass micropipette. This line extended from the straight tube to the end of the curved tip. Another PR line was further generated on the other side of this micropipette using the same process. Finally, after the Au film was etched using the two PR lines as the masking patterns, followed by the removal of the PR using acetone, two Au lines were generated on the outer surface of the glass micropipette. The two approaches mainly differed in the ways of pressing the PR-coated membrane against the curved tip of the micropipette. In the first approach, a clip was applied for this purpose, while in the second approach a nitrogen flux was employed to make the membrane have intimate contact with the curved tip. To date, we have successfully fabricated Au lines on glass micropipettes of tip sizes down to 35 and 5 μm, respectively, using the two approaches. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is required for plant systemic acquired resistance (SAR) to viruses. However, SA-deficient plants adapt to RNA virus infections better, which show a lighter symptom and have less reactive oxygen species (ROS) accumulation. The virus replication levels are higher in the SA-deficient plants during the first 10 days, but lower than the wild-type seedlings after 20 dpi. The higher level of glutathione and ascorbic acid (AsA) in SA-deficient plants may contribute to their alleviated symptoms. Solo virus-control method for mortal viruses results in necrosis and chlorosis, no matter what level of virus RNAs would accumulate. Contrastingly, early and high-dose AsA treatment alleviates the symptom, and eventually inhibits virus replication after 20 days. ROS eliminators could not imitate the effect of AsA, and could neither alleviate symptom nor inhibit virus replication. It suggests that both symptom alleviation and virus replication control should be considered for plant virus cures. [ABSTRACT FROM AUTHOR]

Indirect response (IDR) models have been widely applied to pharmacodynamic (PD) modeling, particularly when delayed response (hysteresis) is present. This paper proposes a class of nonlinear discrete-time autoregressive (AR) models with drug concentrations acting as a time-varying covariate on the asymptote parameter or the autocorrelation parameter of the AR models as an alternative modeling approach for delayed response data. The mathematical derivations revealed the inherent connection between IDR models and nonlinear AR models, and showed that the nonlinear AR models approximate the IDR models when the time interval between response data is small. Simulations demonstrate that the IDR models and the corresponding AR models produce similar temporal response profiles, and as the time interval decreased (i.e., more intensive sampling designs), the AR model based parameter estimates were more comparable to those estimated from the IDR models. In conjunction with mixed-effects modeling, the nonlinear AR models have been shown to well describe a set of simulated longitudinal PK/PD data for a clinical study. Further extensions of the proposed nonlinear AR models are warranted to model irregular and sparse PK/PD data. [ABSTRACT FROM AUTHOR]

In the present work, effects of trace amount of Pr on the microstructure, wettability and mechanical properties of Sn-9Zn solder were studied. The range of Pr content in Sn-9Zn solder alloys varied from 0.01 to 0.25 wt%. Test results indicate that adding appropriate amount of Pr can evidently improve the wettability and mechanical properties of the Sn-9Zn solder alloy. The Sn-9Zn-0.08Pr solder shows the best comprehensive properties compared to other solders with different Pr content. At the same time, notable changes in microstructure were found compared with the Pr-free alloy. The needle-like Zn-rich phase in the Sn-9Zn solder was refined and became more uniform. Moreover, the thickness of the IMC layer at Sn-9Zn/Cu substrate was remarkably depressed with Pr addition. [ABSTRACT FROM AUTHOR]

This study investigated the relative efficiencies of a stereographic display and two monoscopic display schemes for detecting lung nodules in chest computed tomography (CT). The ultimate goal was to determine whether stereoscopic display provides advantages for visualization and interpretation of three-dimensional (3D) medical image datasets. A retrospective study that compared lung nodule detection performances achieved using three different schemes for displaying 3D CT data was conducted. The display modes included slice-by-slice, orthogonal maximum intensity projection (MIP), and stereoscopic display. One hundred lung-cancer screening CT examinations containing 647 nodules were interpreted by eight radiologists, in each of the display modes. Reading times and displayed slab thickness versus time were recorded, as well as the probability, location, and size for each detected nodule. Nodule detection performance was analyzed using the receiver operating characteristic method. The stereo display mode provided higher detection performance with a shorter interpretation time, as compared to the other display modes tested in the study, although the difference was not statistically significant. The analysis also showed that there was no difference in the patterns of displayed slab thickness versus time between the stereo and MIP display modes. Most radiologists preferred reading the 3D data at a slab thickness that corresponded to five CT slices. Our results indicate that stereo display has the potential to improve radiologists' performance for detecting lung nodules in CT datasets. The experience gained in conducting the study also strongly suggests that further benefits can be achieved through providing readers with additional functionality. [ABSTRACT FROM AUTHOR]

To investigate the novel role of lipocalin 2 and its concernment with human nonmetastatic clone 23 type 1 (nm23-H1) and p53 in cervical carcinogenesis, SiHa cervical cancer cells were knocked down for nm23-H and lipocalin 2 or overexpressed by lipocalin 2 genes. We found that the overexpression of lipocalin 2 or knockdown of nm23-H1 genes increased the proliferation of SiHa cancer cells, while knocking down of lipocalin 2 decreased the proliferation of SiHa. Furthermore, knockdown of nm23-H1 or overexpression of lipocalin 2 was associated with reduced expression of p53 and its downstream gene p21. Using tissue microarrays, lipocalin 2 immunoreactivity was significantly elevated in cancer tissues as compared with it in high- or low-grade dysplasia or normal tissues. Serum secreted form lipocalin 2 from patients with cervical cancer increased in comparison with normal controls. Conclusively, secreted form lipocalin 2 reflects its implication in cervical cancer tissues and may be utilized as an adjuvant biomarker. [ABSTRACT FROM PUBLISHER]

This paper presents a versatile detail editing approach for triangular meshes based on filtering the Laplacian coordinates. More specifically, we first compute the Laplacian coordinates of the mesh vertices, then filter the Laplacian coordinates, and finally reconstruct the mesh from the filtered Laplacian coordinates by solving a linear least square system. The proposed detail editing method includes not only feature preserving smoothing but also enhancing. Furthermore, the proposed approach allows interactive editing of some user-specified frequencies and regions. Experimental results demonstrate that our method is much more versatile and faster than the existing methods. [ABSTRACT FROM AUTHOR]

total of 11 sediment samples were collected from the sites along Haihe River-Bohai Bay, with site 1 at the beginning of Haihe River and site 11 in Bohai Bay, about 150 km away from site 1. Quinone profiles were used for the analysis of microbial community as influenced by pollutants in water and sediments, such as heavy metals, and other environmental factors. Nineteen species of quinones were found at site 1 while only six species at sites 10 and 11. Both the diversity of quinone species (DQ) and the number of quinones were higher in the sediments from Haihe River and the near-sea area of Bohai Bay than in those from the deep-sea area. The β diversity values were significantly higher, while Jaccard indexes of similarity were much lower among non-contiguous pairs of sites as compared with the contiguous ones. Cluster analysis indicated that quinone profiles may be grouped into two main clusters (sites 1-7 and sites 8-11), and there were higher similarities within the groups than between groups. Quinone species composition varied at different sites. Ubiquinones such as UQ-8, UQ-9, and UQ-10 and menaquinones such as MK-6, MK-7, MK-8 were isolated from all the sites and accounted for the largest proportions. Pearson correlation analysis revealed that both the number of quinone species and DQ correlated positively with total organic carbon contents in water and sediments, but negatively correlated with salinity and electroconductivity and did not correlate significantly with heavy metal contents in water. [ABSTRACT FROM AUTHOR]

Toxic metal pollution in bodies of water is a source of danger to the health of people living in developing countries. The untreated mine wastes located near some Chinese ore mines may cause water pollution, which ultimately results in various diseases. The aim of the present study is to assess the response of testate amoebae communities to pollution by toxic metals in groundwater, stream water, and aquatic bryophytes in Lanmuchang stream located in the Hg-Tl mineralized area in southwestern Guizhou Province, China. Measurements were made of the levels of Hg, As, Cd, Tl, Cu, Zn, and Pb in three mosses: Hyophila propagulifera, Rhynchostegium riparioides, and Hygroamblystegium tenax. Mean moss concentrations of Hg, As, Cu, Pb, and Zn were significantly higher than stream water values and testate amoebae species richness and abundance were significantly lower in the 'polluted' group. We then studied the correlation between toxic metals and testate amoebae. The total species abundance is correlated negatively to Hg and Cu concentrations. Our results indicated that testate amoebae are sensitive to toxic metal pollution and aquatic bryophytes are bioaccumulators of trace metals, and results also showed potential microecosystem health risks. [ABSTRACT FROM AUTHOR]

Effects of trace amount addition of rare earth Nd on the properties of eutectic Sn-Zn solder were studied in this paper. Results indicate that adding trace rare earth element Nd could remarkably improve the solderability and mechanical properties of Sn-9Zn solder joints. Especially when the content of Nd was 0.06 wt%, the wettability of the solder was improved significantly, and the shear force of Sn-9Zn-0.06Nd solder joint was enhanced by 19.6% as well as pull force increased by 26.6% compared to that of Sn-9Zn solder joint,respectively. It is also found that addition of rare earth Nd could refine the microstructure of the solder and some NdSn phase appeared in the solder matrix. Moreover, the IMCs thickness at the solder/Cu interface was reduced. NdSn phase appeared at the interface with excessive addition of Nd, which is the key reason that deteriorates the mechanical properties of soldered joint. [ABSTRACT FROM AUTHOR]

Background, aim, and scope: The Jiangsu section of the Yangtze River is the downstream of the whole river, serving as an important drinking water source. Persistent toxic substances (PTS), from the industries such as automobile, textile, chemical, and electronic production, are not listed in the National Standard yet and not monitored and controlled. However, pollution of PTS can threaten the environment and human health. In order to understand the pollution status of the PTS contamination and recommend future rationalization of countermeasure, the PTS including organochlorine pesticides (OCPs), polyaromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and phthalates (PAEs) were investigated. Materials and methods: Samples were collected at 15 sites from five main stream sections of the Yangtze River in Jiangsu Province. PTS were extracted using solid phase extract method. The analysis of OCPs, PCBs was performed using GC/ECD and PAHs, PAEs was performed by GC/MS. Results and discussions: The method detection limits are low and the recoveries are from 58.1% to 110.3%. The total concentrations of OCPs, PCBs, PAHs, and PAEs were 0.27∼2.15 ng l, <0.21∼44.4 ng l, 0.012∼3.576 μg l and 0.178∼1.474 μg l, respectively. γ-HCH, PCB28, PCB101, phenanthrene, anthracene, di-n-butyl phthalate, diethyl phthalate, and di-(2-ethylhexyl) phthalate are the major detected PTS. The concentration of most of the PTS was below the environmental quality standards for surface water of China. Conclusions: The pollution status of OCPs, PCBs, PAHs, and PAEs were analyzed. PTS contamination levels of the five main stream sections were relatively low. [ABSTRACT FROM AUTHOR]

Even though the crystal structure of lead telluride (PbTe) has been extensively studied for many years, we discovered that the structure has a strong tendency to form Pb-depleted disks on {001} planes. These disks are around 2-5 nm in diameter and less than 0.5 nm in thickness, with a volume density of around 9 x 1017 cm-3, resulting in lattice strain fields (3-20 nm) on both sides of the disks along their normal directions. Moreover, such disks were also observed in Pb-rich Pb1.3Te, Pb-deficient PbTe1.3, and thallium (Tl)-doped Tl0.01Pb0.99Te and Tl0.02Pb0.98Te crystals. Because of the effects of diffraction contrast imaging by transmission electron microscopy and orientations of the crystals, these native lattice strain fields were incorrectly recognized as precipitates or nanoinclusions in PbTe-based materials. This discovery provides new insight into the formation mechanism of the precipitates or nanoinclusions in PbTe-based materials. [ABSTRACT FROM AUTHOR]

Generation of firebrands from a wildland fire and their distribution downwind are studied using an analytical approach. The processes considered include emission of firebrands, wind-driven transport and the associated spot ignition. Emission of the firebrands from a fire front is treated as a stochastic process reflecting the interaction between gas flow plume and the burning fuel debris formed, with the emission rate being dominated by the rate of fuel consumption, emission factor and a function of firebrand sizes. Analogous to the random distribution of non-burning windborne particles, the transient distribution of firebrands downwind is described by a statistical pattern of Rayleigh form. Number and mass of firebrands landed downwind within the maximum travel distance are then determined by integration over the entire impact period during fire spread and burning-out processes. Application of the model to the bushfire occurred in Canberra, Australia in 2003 indicates that this model provides reasonable prediction in the distribution of firebrands downwind, and quantitatively exhibits the role of ember attack in massive destruction of houses at urban interface. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPB) refer to the bacteria beneficial to plants, and they may affect the growth and development of plants directly or indirectly. This article studied the activities of nitrogen fixation and colonization of a strain of PGPB, Klebsiella pneumoniae NG14, which was isolated from the rice root surface. The results showed that NG14 harbouring the nifH gene had nitrogenase activity, N-fixing activity, and was able to colonize on the root surface and within the cavity of root vascular tissues of rice. Using proteomics technology to study the differences and changes of membrane proteins (MP) of NG14 bacterial biofilm in non-biological surface, 28 proteins showing significant differences before and after the formation of bacterial biofilm have been identified, in which the precursors of membrane pore protein OmpC relevant to osmotic stress resistance was up-regulated. This study would have positive significance on further understanding of the direct and indirect promotion effects of PGPB and related mechanisms. [ABSTRACT FROM AUTHOR]

Content-based image retrieval approach was used in our computer-aided detection (CAD) schemes for breast cancer detection with mammography. In this study, we assessed CAD performance and reliability using a reference database including 1500 positive (breast mass) regions of interest (ROIs) and1500 normal ROIs. To test the relationship between CAD performance and the similarity level between the queried ROI and the retrieved ROIs, we applied a set of similarity thresholds to the retrieved similar ROIs selected by the CADschemes for all queried suspicious regions, and used only the ROIs that were above the threshold for assessing CAD performance at each threshold level. Using the leave-one-out testing method, we computed areas under receiver operating characteristic (ROC) curves ( A) to assess CAD performance. The experimental results showed that as threshold increase, (1) less true positive ROIs can be referenced in the database than normal ROIs and (2) the A value was monotonically increased from 0.854±0.004 to 0.932±0.016. This study suggests that (1) in order to more accurately detect and diagnose subtle masses, a large and diverse database is required, and (2) assessing the reliability of the decision scores based on the similarity measurement is important in application of the CBIR-based CAD schemes when the limited database is used. [ABSTRACT FROM AUTHOR]

The measured strains in the continuously reinforced concrete pavement (CRCP) cannot simply be used to calculate the concrete stresses by multiplying the elastic modulus of concrete, because the measured strains include both the stress dependent and independent strains. The setting temperature of concrete and the measured strain at this temperature should be used to calculate the temperature difference and the strain increment. The early-age strains in the concrete and steel of CRCP were measured in this paper. The measured concrete strains include the total strain, the stress independent strain and the initial strain at setting temperature. These measured values can be used not only to accurately calculate the stresses in concrete and steel but also to determine the accurate boundary conditions in the numerical modeling of CRCP subject to environmental loading. On the boundary conditions used in analysis of the early-age CRCP under environmental loading, epoxy coated steel is not completely bonded with concrete. Additionally, the perfectly free or restrained boundary condition across cracking is not true, and the longitudinal steel strains across cracking will help develop the proper boundary condition across cracking. The calculated stress was verified from the comparison between the calculated stress at the instant of cracking and the measured tensile strength. [ABSTRACT FROM AUTHOR]

Pseudomonas putida KT2442 has been a well-studied producer of medium-chain-length (mcl) polyhydroxyalkanoate (PHA) copolymers containing C6 ~ C14 monomer units. A mutant was constructed from P. putida KT2442 by deleting its phaG gene encoding R-3-hydroxyacyl-ACP-CoA transacylase and several other β-oxidation related genes including fadB, fadA, fadB2x, and fadAx. This mutant termed P. putida KTHH03 synthesized mcl homopolymers including poly(3-hydroxyhexanoate) (PHHx) and poly(3-hydroxyheptanoate) (PHHp), together with a near homopolymer poly(3-hydroxyoctanoate- co-2 mol% 3-hydroxyhexanoate) (PHO*) in presence of hexanoate, heptanoate, and octanoate, respectively. When deleted with its mcl PHA synthase genes phaC1 and phaC2, the recombinant mutant termed P. putida KTHH08 harboring pZWJ4-31 containing PHA synthesis operon phaPCJ from Aeromonas hydrophila 4AK4 accumulated homopolymer poly(3-hydroxyvalerate) (PHV) when valerate was used as carbon source. The phaC deleted recombinant mutant termed P. putida KTHH06 harboring pBHH01 holding PHA synthase PhbC from Ralstonia eutropha produced homopolymers poly(3-hydroxybutyrate) (PHB) and poly(4-hydroxybutyrate) using γ-butyrolactone was added as precursor. All the homopolymers were physically characterized. Their weight average molecular weights ranged from 1.8 × 10 to 1.6 × 10, their thermal stability changed with side chain lengths. The derivatives of P. putida KT2442 have been developed into a platform for production of various PHA homopolymers. [ABSTRACT FROM AUTHOR]