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Donor-like defects are activated and acceptor-like defects are passivated when commercial AlGaN/GaN high electron mobility transistors (HEMTs) are irradiated with 10-keV X-rays or 1.8-MeV protons at low fluence. Displacement-damage-induced creation of acceptor-like defects is observed at higher proton fluences. The dehydrogenation of FeGa-H and $\text{O}_{\mathrm {N}}$ -H substitutional impurities and generation of N-vacancy-related defects most likely account for the modest degradation of these devices at high proton fluences. Low-frequency (LF) noise measurements identify FeGa defects as prominent generation–recombination (G–R) centers in these devices. These results enable recalibration of the Dutta–Horn model of LF noise and increased insight into the defect identities and energy distributions in AlGaN/GaN HEMTs.

A self‐consistent regional‐scale seismic velocity model with resolution from seismogenic depth to the surface is crucial for seismic hazard assessment. Though Southern California is the most seismically imaged region in the world, techniques with high near‐surface sensitivity have been applied only in disparate local areas and have not been incorporated into a unified model with deeper resolution. In the present work, we obtain isotropic values for Rayleigh wave phase velocity and ellipticity in Southern California by cross‐correlating daily time series from the year 2015 across 315 regional stations in period ranges 6 to 18 s. Leveraging the complementary sensitivity of the two Rayleigh wave data sets, we combine H/V and phase velocity measurements to determine a new 3‐D shear velocity model in a Bayesian joint inversion framework. The new model has greatly improved shallow resolution compared to the Southern California Earthquake Center CVMS4.26 reference model. Well‐known large‐scale features common to previous studies are resolved, including velocity contrasts across the San Andreas, San Jacinto, Garlock, and Elsinore faults, midcrustal high‐velocity structure beneath the Mojave Desert, and shallow Moho beneath the Salton Trough. Other prominent features that have previously only been imaged in focused local studies include the correct sedimentary thickness of the southern Central Valley, fold structure of the Ventura and Oak Ridge Anticlines, and velocity contrast across the Newport‐Inglewood fault. The new shallow structure will greatly impact simulation‐based studies of seismic hazard, especially in the near‐surface low‐velocity zones beneath densely populated areas like the Los Angeles, San Bernardino, and Ventura Basins. Ambient noise cross‐correlations across Southern California show clear Rayleigh waves with measurable phase and amplitude informationAmplitude information, through Rayleigh ellipticity (H/V), gives new constraint on near‐surface structure due to shallow crust sensitivityShallow crust structures previously only seen in local studies are recovered regionally via joint inversion of phase velocity and H/V

Despite considerable efforts over the past decade, only 34 fast radio bursts—intense bursts of radio emission from beyond our Galaxy—have been reported1,2. Attempts to understand the population as a whole have been hindered by the highly heterogeneous nature of the searches, which have been conducted with telescopes of different sensitivities, at a range of radio frequencies, and in environments corrupted by different levels of radio-frequency interference from human activity. Searches have been further complicated by uncertain burst positions and brightnesses—a consequence of the transient nature of the sources and the poor angular resolution of the detecting instruments. The discovery of repeating bursts from one source3, and its subsequent localization4to a dwarf galaxy at a distance of 3.7 billion light years, confirmed that the population of fast radio bursts is located at cosmological distances. However, the nature of the emission remains elusive. Here we report a well controlled, wide-field radio survey for these bursts. We found 20, none of which repeated during follow-up observations between 185–1,097 hours after the initial detections. The sample includes both the nearest and the most energetic bursts detected so far. The survey demonstrates that there is a relationship between burst dispersion and brightness and that the high-fluence bursts are the nearby analogues of the more distant events found in higher-sensitivity, narrower-field surveys5.

Imatinib-induced ophthalmological side-effects, including conjunctiva hemorrhage and periorbital oedema, although very common and still remain relatively little understood. The present study investigated the effects of genetic polymorphisms of drug targets and membrane transporters on these side effects. We found that the minor allele of EGFR rs10258429 and SLC22A1 rs683369 were significant risk determinants of conjunctival hemorrhage with OR of 7.061 (95%CI=1.791-27.837, P=0.005 for EGFR rs10258429 CT+TT vs CC), and 4.809 (95%CI=1.267–18.431, P=0.021 for SLC22A1 rs683369 GG+CG vs CC). The minor allele of SLC22A5 rs274558 and ABCB1 rs2235040 were protective factors to periorbital oedema with OR of 0.313 (95%CI=0.149–0.656, P=0.002 for SLC22A5 rs274558 AA+AG vs GG), and 0.253 (95%CI=0.079–0.805, P=0.020 for ABCB1 rs2235040 CT vs CC). These results indicated that variants in EGFR, SLC22A1, SLC22A5 and ABCB1 influenced the incidence of Imatinib-induced ophthalmological toxicities, and polymorphism analyses in associated genes might be beneficial to optimize Imatinib treatment.

La corrosion-érosion (Flow Accelerated Corrosion - FAC)affecte les composants en acier au carbone des circuits secondaires des centrales REP. L’utilisation du logiciel BRT-CICERO™ permet à EDF de mener des programmes d’inspection efficaces et d’éviter les fuites dans les circuits secondaires. Du fait des conditions de fonctionnement, les circuits ARE de régulation du débit d’eau d’alimentation des générateurs de vapeur peuvent être affectés par la corrosion-érosion.

Triple-negative breast cancer (TNBC) is very aggressive and currently has no specific therapeutic targets; as a consequence, TNBC exhibits poor clinical outcome. In this study, we showed that cancerous inhibitor of protein phosphatase 2A (Cip2a) represents a promising target in TNBC because Cip2a was highly expressed in TNBC cells and tumor tissues, and its expression showed an inverse correlation with overall survival in patients with TNBC. We found that inhibition of Cip2a in TNBC cells induced cell cycle arrest at the G2/M phase, inhibited cell proliferation and delayed tumor growth in the xenograft model. Moreover, Cip2a markedly decreased the expression and nuclear localization of p27Kip1 and this is critical for the ability of Cip2a to promote TNBC progression. Mechanistically, our studies showed that Cip2a promoted p27Kip1 phosphoration at Ser10 via inhibiting Akt-associated PP2A activity, which seems to relocalize p27Kip1 to the cytoplasm in TNBC cells. On the other hand, Cip2a also recruited c-myc to mediate the transcriptional inhibition of p27Kip1. Notably, we observed negative correlation between Cip2a and p27Kip1 expression in TNBC specimens. In addition, our data showed that Cip2a depletion could sensitize TNBC to PARP inhibition. Collectively, these data suggested that Cip2a effectively promotes TNBC cell cycle progression and tumor growth via regulation of PP2A/c-myc/p27Kip1 signaling, which could serve as a potential therapeutic target for TNBC patients.

Acute erythroid leukemia (AEL), characterized by a predominant erythroid proliferation, is a subtype of acute myelogenous leukemia. The genetic basis of AEL remains poorly defined. Through whole-exome sequencing, we identified high frequencies of mutations in CEBPA(32.7%), GATA2(22.4%), NPM1(15.5%), SETBP1(12.1%) and U2AF1(12.1%). Structure prediction analysis revealed that most of the GATA2mutations were located at the DNA-binding N-terminal zinc-finger near the DNA-binding interface, suggesting that mutations could result in at least partial inactivation of GATA2protein. On co-transfection of a GATA-responsive reporter construct together with plasmids expressing either GATA2wild-type or GATA2ZF1 mutants (P304H, L321P and R330X) in 293T cells, we found a reduced transcriptional activation in cells transfected with GATA2 mutants. To determine whether reduced GATA2function is involved in leukemogenesis of AEL, we transfected 32D cells with GATA2mutants and evaluated the impact of GATA2mutations on erythroid differentiation. Our data revealed an increased expression of erythroid-related antigens Ter-119, β-globin and βh1-globin, as well as increased hemoglobin positivity in 32D cells transfected with GATA2mutants compared with control cells. Our results suggest that the decline of GATA2resulting from mutations contributes to the erythroid commitment, differentiation and the development of AEL.

We present observations of ten metal-poor halo stars with the metallicity range $-2.3 < [$Fe/H$] < -1.4$and derive their stellar parameters, acquire some elemental abundances relative to iron and discuss the relation between the abundance ratio and the metallicity. It was found that oxygen abundances are nearly constant at a level of 0.6 dex for our metal-poor halo stars when the non-LTE correction is considered. The α-elements (Mg, Si, Ca and Ti) are overabundant relative to Fe and decrease with increasing metallicity. We also obtained a significant underabundant non-LTE [Na/Fe] ratio from Na iD lines which have a large deviation from the LTE assumption. Scandium is marginally overabundant with respect to iron and tends to decrease with increasing metallicity like the α-elements. A nearly solar value of [Cr/Fe] ratio and underabundant [Mn/Fe] ratio are obtained.

Myogenesis is an important biological process that occurs during both skeletal muscle regeneration and postnatal growth. Growing evidence points to the critical role of microRNAs (miRNAs) in myogenesis. Our analysis of miRNA expression patterns reveal that miRNAs of miR-17-92 cluster are dramatically downregulated in C2C12 cells after myogenesis stimulation, are strongly induced in mouse skeletal muscle after injury and decrease steadily thereafter and are downregulated with age in skeletal muscle during mouse and porcine postnatal growth. However, their roles in muscle developmental processes remain elusive. We show that the miR-17-92 cluster promotes mouse myoblast proliferation but inhibits myotube formation. miR-17, -20a and -92a target the actin-associated protein enigma homolog 1 (ENH1). The silencing of ENH1 increased the nuclear accumulation of the inhibitor of differentiation 1 (Id1) and represses myogenic differentiation. Furthermore, the injection of adenovirus expressing miR-20a into the tibialia anterior muscle downregulates ENH1 and delays regeneration. In addition, the downregulation of miR-17-92 during myogenesis is transcriptionally regulated by E2F1. Overall, our results reveal a E2F1/miR-17-92/ENH1/Id1 regulatory axis during myogenesis.

The EVI1gene is a transcriptional regulator of hematopoietic stem cell self renewal and its overexpression is associated with adverse prognosis in de novoAML. Whether the overexpression of EVI1also predicts poor outcome of AML patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first CR (CR1) is still unclear. Thirty-two (21.2%) out of 151 patients were categorized as high EVI1expression (EVI1+), and 119 (78.8%) patients were categorized as low EVI1expression (EVI1−). The frequency of EVI1+ was much higher in the adverse-risk group than the intermediate-risk group (53% vs 19%, P=0.005). EVI1+ patients were significantly likely to harbor with translocations involving the MLLgene on 11q23 (8/9). Significantly poor results were observed in the EVI1+ cohort in terms of leukemia-free survival (LFS) (in 24 months 52.6 vs 71.0%, P=0.027), overall survival (OS) (in 24 months 52.8 vs 72.4%, P=0.012), and cumulative incidence of relapse (in 24 months 39.5 vs 22.5%, P=0.013). Multivariable analysis revealed that low EVI1expression as an independent prognostic factor favoring LFS (hazards ratio=0.47, 95% confidence interval 0.26–0.86, P=0.01) but not OS. Our results indicate high EVI1expression might predict high risk of relapse in AML patients undergoing myeloablative allo-HSCT in CR1.

We obtain abundances of α, iron peak and neutron capture (n-capture) process elements in four Ba stars HD 26886, HD 27271, HD 50082 and HD 98839 based on high resolution, high signal-to-noise spectra. We find that all of these Ba stars are disk stars. Their αand iron peak elements are similar to the solar abundances. The n-capture process elements are overabundant relative to the Sun. In particular, the second peak slow neutron capture process (s-process) elements, Ba and La, are higher than the first peak s-process elements, Y and Zr. Analyzing the abundances of four sample stars, the heavy-element abundances of the strong Ba star HD 50082 are higher than those of other three mild Ba stars. The stellar mass of the strong Ba star HD 50082 is 1.32 $M_{\odot}$(+0.28, $-0.22~M_{\odot}$), which is consistent with the average mass of strong Ba stars (1.5 $M_{\odot}$). For mild Ba star HD 27271, we derive 1.90 $M_{\odot}$(+0.25, $-0.20~M_{\odot}$), consistent with the average mass of mild Ba stars (1.9 $M_{\odot}$, with 0.6 $M_{\odot}$white dwarf companion). For mild Ba star HD 26886, the derived 2.78 $M_\odot$(+0.75, $-0.78~M_{\odot}$) is consistent with the average 2.3 $M_\odot$of mild Ba stars with 0.67 $M_\odot$companion white dwarfs within the errors. Mass of mild Ba star HD 98839 is high to 3.62 $M_\odot$, which inspires more thoughts on the formation of Ba star phenomenon. Using our angular momentum conservation theoretical model of wind accretion of Ba binary systems, we obtain the theoretical heavy-element abundances of Ba stars that best fit our data. The results show that the observed abundances of the typical strong Ba star HD 50082 and the typical mild Ba star HD 27271 are consistent with the theoretical results very well. This suggests that their heavy-element abundances were caused by accreting the ejecta of AGB stars, the progenitors of the present white dwarf companions, through stellar wind. However, wind accretion scenario cannot explain the observed abundance pattern of the mild Ba star HD 26886 with shorter orbital period ($P=$1263.2 d). The mild Ba star HD 98839 with high mass (up to 3.62 $M_{\odot}$) and very long orbital period ($P>$11 000 d) may be either a star with the heavy elements enriched by itself or a “true Ba" star.

Rod-like ZrB2powders were synthesised at 1500°C in vacuum by boro/carbothermal reduction using ZrO2, B4C and graphite as the starting materials. During the heating process, the ZrB2grains primarily grow along the caxis to form a rod-like morphology without any heterogeneous catalyst. The final products are pure rod-like ZrB2particles, which are thought to be promising starting powders to prepare high performance ultrahigh temperature ceramics with unique microstructures such as textured one through tape casting process.

AbstractIn this paper, a new delta-connected autotransformer based 36-pulse AC-DC converter is proposed to feed direct torque controlled induction motor drives. Parameters and winding arrangements of the autotransformer and interphase reactor are given. Mathematical analysis of the input line current and output voltage is presented. The results show that the proposed converter can eliminate less than 35thharmonics in the supply current, and the equivalent kilovoltampere (kVA) rating of the autotransformer is 0.158Po, where Pois the output power of the load. Simulation results confirm that this topology is capable of suppressing less than 35th harmonics in the supply current. The power factor is also improved to near unity under varying loads. Several power quality indices are presented to compare the performance of 12-, 24-and 36-pulse rectifiers.

As environmental temperature decreases, the amount of retained austenite is more likely to greatly reduce due to the thermal austenite–martensite transformation caused by the decreased thermal stability of retained austenite, probably making its amount lower than the required content. In the present study, the thermal stability of retained austenite in Cr–Ni weld metals was investigated to see whether sufficient retained austenite can be maintained at low temperatures. The specific experimental procedure is as follows: briefly, the samples were cooled in turn from room temperature to 0, -20, -40, -60, -80, -100 and -196°C; the amount of retained austenite at the above temperatures was measured using X-ray diffraction. Through investigating the dependence of the content of retained austenite on temperature, it was revealed that when the content of retained austenite is <20, retained austenite can be maintained until -196°C.

Lower deep venous thrombosis (DVT) is one of the major complications of patients with tumors or patients undergoing major surgery. Electrical acupoint stimulation, an established technique of traditional Chinese medicine (TCM), can be well combined with Western medicine to reduce the incidence of postoperative DVT, especially in elderly patients.

To outline the characteristics and outcomes of eye injuries in the Chinese People's Liberation Army.

Reliability allocation optimization problem of a complex mechatronic system is a highly nonlinear constrained optimization problem, and hence solution to this kind of problem is of NP-hardness even with moderate scale. Due to the nonlinearity combined with multiple local extreme values, traditional optimization techniques fail to arrive at the global or nearly global optimal solution to the problem. Genetic algorithm incorporated with neighboring domain traversal searching technique is utilized in this paper to solve the complex mechatronic system reliability optimization allocation problem. Reliability allocation optimization of the life-support system in a space capsule, being a typical non serial-parallel system, is specifically demonstrated to show the satisfactory convergence performance as well as the important practical value of hybrid genetic algorithm. The simulation results show that the proposed method may gain better precision in solving the complex mechatronic system reliability optimization problem.

Newly built Jiamusi (JME) radar and Hokkaido East (HOK) radar data reveal statistical features of the mid‐latitude ionospheric irregularities during quiet times. In this paper, the distribution features and seasonal variations of the scattering occurrence rate and convection velocity of the ionospheric, F‐region irregularities between 45°N and 60°N magnetic latitude (MLAT) during geomagnetic quiet times are studied by using one‐year observation data from the JME radar and HOK radar. The results show that the scattering occurrence rate is strongest in summer and weakest in winter in this region, and the highest value always appears on the dusk side, especially in summer and the equinox. Line‐of‐sight (LOS) velocity also shows significant seasonal variation. It is stronger in winter and the equinox than in summer, which is in good agreement with previously reported observations from six midlatitude Super Dual Auroral Radar Network radars in the North American sector. An interesting new finding is that on the night side, LOS velocity decreases first and then increases as the MLAT increases from 45°N to 56°N, particularly in summer and the equinox. This implies that there is a velocity reversal region during the geomagnetic quiet time in regard to night side, mid‐latitude, ionospheric convection. The distribution features and seasonal variations of the scattering occurrence rate and convection velocity of the F‐region irregularities between 45° to 56° magnetic latitude during the geomagnetically quiet time are studied by using one‐year observation data from the Jimausi radar and the Hokkaido East radar. Jiamusi radar data are used to study the statistical features of the quiet time, mid‐latitude, ionospheric irregularitiesSeasonal variations in the scattering occurrence rate and line of sight velocity between 45° and 56°N magnetic latitude during geomagnetic quiet time are studiedAt night side, there is a narrow ionospheric convection velocity reversal region in middle latitudes during geomagnetic quiet time Jiamusi radar data are used to study the statistical features of the quiet time, mid‐latitude, ionospheric irregularities Seasonal variations in the scattering occurrence rate and line of sight velocity between 45° and 56°N magnetic latitude during geomagnetic quiet time are studied At night side, there is a narrow ionospheric convection velocity reversal region in middle latitudes during geomagnetic quiet time

Torsion of a flat-ended elastic bar pressed onto an elastically similar half-space and subject to torsion, in the presence of friction, is used as a vehicle to study complete contact subject to in-plane and anti-plane shearing forces. It is shown that, below a critical coefficient of friction, slip starts at the edge and progress inwards as the torsion is increased, whereas above this critical value slip starts a little way in from the edge and progress both inwards and outwards. Care is taken to preserve frictional orthogonality, with slip modelled as a piecewise-linear distribution of edge and screw dislocations. The solutions may be applied to any complete contact edge, as the problem is solved within the context of a Williams eigenexpansion. [Copyright &y& Elsevier]

A highly pathogenic pig disease emerged in China in 2006, which was characterized by prolonged high fever, red discoloration of the body, and blue ears associated with high mortality. Porcine reproductive and respiratory syndrome virus (PRRSV) was isolated as the single most prominent virus in the samples collected from affected pigs. The full-length genomic sequence of the virus revealed two distinct deletions in the non-structural protein 2 (NSP2) in comparison to all previously reported North American genotype PRRSV. Through extensive surveys in 14 different provinces, 56 additional PRRSV isolates were obtained from affected farms. All of the isolates were found to contain identical deletions in NSP2. To confirm the etiology, eight 60-day-old PRRSV-free pigs were divided into two groups and the test group was intranasally infected at a titer of 2?×?105.0tissue culture infectious dose 50 per pig. The inoculated pigs all died at 7, 8, 12, 16, or 21?days post-inoculation with their clinical and pathological findings similar to those in the field. The viruses recovered from dead pigs were identical to the inoculated virus in NSP2 and GP5 genes. Our study shows that the recently emerged PRRSV in China is characterized by two discontiguous deletions in NSP2 and is the cause for the current epizootics in China.

Introduction and Aims:Mucin 1 (MUC1) is a transmembrane glycoprotein that is overexpressed in many tumor types, including breast, pancreatic, and ovarian cancer. The aim of this study was to create a construct containing sodium-iodide symporter (NIS) under the control of the 0.8-kb MUC1 promoter to infect pancreatic cancer cells both in vitro and in vivo, to investigate the potential for radioiodide imaging and ablation of this disease. Methodology:We amplified the 797-bp MUC1 promoter by two-step nested PCR. Subsequently, a replication-deficient adenoviral construct was created containing the MUC1 promoter followed by the human NIS gene. Iodide uptake assays and immunofluorescence were used to confirm NIS expression and function. Pancreatic cancer xenografts in mice were infected with Ad/MUC1/NIS and then imaged and treated using radioiodide. Results:A 23- and 15.5-fold increase in iodide uptake was observed in Ad/MUC1/NIS-infected MUC1-positive Capan-2 and SW1990 cells with no significant increase observed in MUC1-negative Hela cells or in cells infected with the control virus. The in vivo study showed a clear image of Ad/MUC1/NIS-infected tumor xenografts using 125I. Administration of a therapeutic dose of 131I resulted in a regression in size to 76 ± 15% of their original volume, whereas control tumors continued to increase in size to 200% of their original volume. Conclusions:These results show that the 0.8-kb MUC1 promoter was successfully used to drive human NIS-targeted expression in pancreatic cancer cells, and Ad/ MUCI/NIS-mediated radiotherapy can make pancreatic cancer xenografts in mice shrinking. This could potentially have applications for both imaging and therapy in other MUC1-positive tumors. Copyright © 2007 S. Karger AG, Basel and IAP

This paper proposes an optimal interpolation approach to generate cutter paths in the form of polar coordinate for machining noncircular contours. The cutter path obtained with the approach consists of a series of Archimedes’ spiral segments and the number of segments is the fewest under the condition that the interpolation error completely satisfies the specified limit value. It can be also evidenced that the profile error of the machined contour due to the cutter path is perfectly controlled within the specified interpolation accuracy limit. The result of applying the approach to the contour machining of a disc cam sufficiently illustrates the effectiveness of the proposed approach.

Abstract: The evaporation process of a multi-component droplet has been studied utilizing optical diagnostic techniques. Investigation focused on the measurements of the different volatility mixtures and the variation of the mass fraction within a droplet of different components. The method for determining the temperature of a multicomponent droplet containing nonvolatile and volatile compositions has been proposed. For a droplet with two volatile compositions, such as water and ethanol mixture, the model of evaporation for droplet temperature measurements was also suggested based on the experimental data. Droplets with different mass fractions of each component under different temperature conditions were measured utilizing a primary rainbow refractometer and a recently improved phase-Doppler analyzer. It was also found that the droplet temperature could hardly reach its saturation temperature within the droplet unlike explained by previous researchers. The effects of temperature gradient within an evaporating microdroplet and the temperature discontinuity on the evaporating surface have been discussed.

Cyclopentadienyl-free disilyl amide complexes [(Me2N)3M(SiBu^tPh2)2]^- (M = Zr, 1; Hf, 2 as [Li(THF)4]⁺ salts), K(18-crown-6)3/2{(Me2N)3M[(Me3Si)2Si-(CH2)2-Si(SiMe3)2]} (M = Zr, 3; Hf, 4), (Me2N)3Ta[Si(SiMe3)3]2 (5), (Me2N)3Ta(SiBu^tPh2)2 (6), and (Me2N)3Ta(SiBu^tPh2)[Si(SiMe3)3] (7) have been prepared. The structures of 1−4 have been determined by X-ray single-crystal diffraction. The two −Si(SiMe3)3^- ligands in (Me2N)3Ta[Si(SiMe3)3]2 (5) were replaced sequentially by the −SiBu^tPh2^- anions to give (Me2N)3Ta(SiBu^tPh2)[Si(SiMe3)3] (7) and (Me2N)3Ta(SiBu^tPh2)2 (6). The silyl ligand in (Me2N)3Zr-Si(SiMe3)3 was found to undergo a reversible exchange with SiBu^tPh2^-, probably through a disilyl intermediate, to reach the following equilibrium:  (Me2N)3ZrSi(SiMe3)3 + SiBu^tPh2^- &rlhar2; (Me2N)3ZrSiBu^tPh2 + Si(SiMe3)3^- with ΔH° = 4.6(0.5) kcal/mol and ΔS° = −7(2) eu. A similar exchange involving [(Me2N)3M(SiBu^tPh2)2]^- (M = Zr, 1; Hf, 2) was observed:  (Me2N)3ZrSiBu^tPh2 + SiBu^tPh2^- &rlhar2; 1 with the estimated free energy of activation ΔG^&thermod; = 14.1(0.5) kcal/mol. (Me2N)3Ta(SiBu^tPh2)2 (6) and (Me2N)3Ta(SiBu^tPh2)[Si(SiMe3)3] (7) are thermally unstable. Kinetic studies give the activation parameters of the decomposition of 7:  ΔH^&thermod; = 22.8(1.3) kcal/mol and ΔS^&thermod; = −3(5) eu.

Poly-dl-lactide end-capped by a protected thiol was synthesized by bulk ring-opening polymerization (ROP) of dl-lactide initiated by the reaction product of aluminum isopropoxide [Al (ⁱOPr) 3] with α- (2,4-dinitrophenylsulfenyl) ethanol. After the thiol deprotection, PLA-SH was used to stabilize gold nanoparticles. Either these nanoparticles were prepared in the presence of PLA-SH, or PLA-SH was substituted for part of the undecanethiol (C11SH) that stabilized preformed gold nanoparticles. In contrast to C11SH-coated nanoparticles, those stabilized by PLA-SH were successfully entrapped into 100-nm PLA nanocarriers prepared by nanoprecipitation. This is an easy technique to label PLA biocarriers and therefore trace their fate in vivo.

This article presents the development of a dynamic path search algorithm for an intelligent navigator used to guide an autonomous agricultural tractor to track the desired path and make turns at the end of field. This dynamic path search algorithm uses posture sensors to determine the current tractor position and a tractor dynamics model to estimate the future tractor position. The posture sensors include a real-time kinematic global positioning system (RTK-GPS) receiver and a fiber-optic gyroscope (FOG). The outputs from the dynamic path search algorithm are tractor lateral deviation and the desired yaw angle. Based on these outputs, an intelligent navigator will create appropriate steering angles to guide the tractor along the desired path. The developed dynamic path search algorithm was first evaluated in computer simulation and then validated via field tests. The path tracking results obtained from field tests indicated that the root mean squared (RMS) error of the tractor lateral deviation was less than 0.03 m, and the maximum lateral deviation was less than 0.1 m when the tractor was traveling on straight or slightly curved paths at speeds up to 3.5 m/s. The results verified that this dynamic path search algorithm could satisfy the need to navigate an autonomous tractor accurately tracking the desired path to perform agricultural operations. [ABSTRACT FROM AUTHOR]

High order refractions have been found to have a great impact on optical particle sizing using phase-Doppler anemometry (PDA) especially when the relative refractive index of the media is less than one. The high order refractions cannot be neglected because of the differences in spatial frequencies and motion directions of each order. A model of phase-size correlation is proposed that considers these high order refractions. By using the conversion factors of the high order refractions, the particle diameter can be determined. The capability of the newly developed method was evaluated by using generalized Lorenz Mie theory (GLMT), which was validated by experiments. The results of the simulation and experiments are compared with those based on the conventional method. An optimization method for accurately sizing air bubbles in water has been suggested.High order refractions have been found to have a great impact on optical particle sizing using phase-Doppler anemometry (PDA) especially when the relative refractive index of the media is less than one. The high order refractions cannot be neglected because of the differences in spatial frequencies and motion directions of each order. A model of phase-size correlation is proposed that considers these high order refractions. By using the conversion factors of the high order refractions, the particle diameter can be determined. The capability of the newly developed method was evaluated by using generalized Lorenz Mie theory (GLMT), which was validated by experiments. The results of the simulation and experiments are compared with those based on the conventional method. An optimization method for accurately sizing air bubbles in water has been suggested.

A novel method for fabrication of highly oriented polyaniline (PANI) nanowires without removal of the template was developed by combining self‐assembly and template synthesis techniques. By using a self‐assembly process under inhibition conditions, oriented arrays of PANI nanowires growing out of the nanoporous template were obtained, with nanowire diameters ranging from 110 to 190 nm and lengths of several micrometers. The lengths of these wires can be roughly controlled by the polymerization time.

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On the basis of high-resolution echelle spectra obtained with the Coudé Echelle Spectrograph attached to the 2.16 m telescope at the Beijing Astronomical Observatory (Xinglong, China) for Sirius and Vega, we performed an elemental abundance analysis of 29 ions, in which 23 elements are included, with Teff= 9880, log g= 4.40, [Fe/H] = 0.50, and ?t= 1.85 km s-1for Sirius and Teff= 9430, log g= 3.95, [Fe/H] = -0.57, and ?t= 1.50 km s-1for Vega. The results show different abundance patterns for these two stars. The iron peak elements seem to be enhanced by about 1.0 dex in Sirius relative to Vega. Comparison with previous investigations is present.

Due to the influence of the welding thermal cycle, the toughness of structural steel generally degenerates. Recently, the intercritically reheated coarse-grained heat-affected zone (IC CG HAZ) was found to demonstrate the worst toughness in welded joint, which was associated with its fracture mechanism. In this article, two IC CG HAZs of a structural steel were prepared by welding thermal-cycle simulation techniques. For the two IC CG HAZs, the static and dynamic fracture toughness were evaluated; the fracture mechanism was also studied. Under both static and dynamic loading, cracks in the IC CG HAZ were found to initiate at the intersection of bainitic ferrite αB/0packets with different orientations, followed by propagation in cleavage. In some crack propagation regions, adjacent cleavage facets are connected by shear, thus producing dimple zones. Though the brittle fracture initiation mechanism remains unchanged, the cleavage facet size, the proportion of the dimple zones between facets, and the distance from the cracking initiation site to the crack tip vary with loading speed and welding conditions. These changes were found to be related to the variations caused by strain rate and welding conditions in fracture toughness for the IC CG HAZs.

A novel method for determining the mutual diffusion coefficient using rheometry is presented. The method includes mathematical modeling for mutual diffusion at polymer/polymer interfaces and experimental determination of material parameters for the model. The model combines the concepts of the reptation theory and the fast-mode model applied to miscible dissimilar polymers brought into intimate contact in the molten state. The material parameters for the model are obtained from experiments in which the dynamic complex shear modulus, G*, is measured in parallel-plate geometry under small amplitude of deformation as a function of time and frequency for a sandwich-like assembly. The technique was applied to the poly(methyl methacrylate) (PMMA)/poly(styrene acrylonitrile) (SAN) system, and the measured mutual diffusion coefficient was found to be in agreement with the values reported in the literature for the same system.

A practical approach towards evaluating form deviations of 2D complex contour profiles from the coordinate measurement data of discrete points is proposed. In this approach, a 2D complex contour is represented approximately by the combination of straight line and circular arc segments under the condition of satisfying the prespecified interpolation accuracy. The form deviation of a measured point is calculated relative to the approximate contour and the form deviation of the whole contour is evaluated using either the minimum zone criterion (MZC) or the least squares criterion (LSC). It has been demonstrated that the difference between the deviation definitions, one relative to the original contour and the other to the approximate contour, is not larger than the prespecified accuracy value, i.e. the evaluation precision of the form deviation can be sufficiently guaranteed. The effectiveness and the efficiency of the approach are verified with a practical example of a planar cam contour. Moreover, a weighted LSC technique is proposed in order to obtain a rational evaluation result for the measured points with non-uniform length interval.: