Search

Hedychin E (1), a novel labdane-type norditerpenoid, and hedychin F (2), a new labdane-type dinorditerpenoid, were isolated from the rhizomes of Hedychium forrestii. Their structures were determined through a combination of spectroscopic analysis and X-ray single-crystal diffractions. Hedychin E (1) is an unprecedented 6-norditerpenoid with a fused tetrahydrofuran-lactone motif, and a reasonable biosynthetic pathway for 1was proposed. Compound 2showed a significant anti-inflammatory effect against LPS-induced NO production in macrophage RAW264.7 cells with an IC50value of 21.0 μM.

A new combination of laser scanning confocal microscope (LSCM) and electron backscattering diffraction (EBSD) with a field-emission scanning electron microscope (SEM) is utilized to study the mechanism of bainite transformation in reheated low carbon bainitic weld metal. The LSCM observations show that laths grow on the surface at various rates, from 30 μm/s to 240 μm/s, which is greatly larger than those referred in literature for bainite. In order to confirm that the laths are bainite and not surface martensite, additional experiments were performed. The crystallographic characteristics of surface bainite were compared with those of bulk bainite obtained during isothermal treatments and those of bulk martensite obtained by water quenching. By means of a dedicated EBSD data-treatment software, orientation relationship, variant selection and packet groups were identified; it was shown that both the surface laths and bulk bainite share the same misorientation, habit plane, and have similar variant distribution. Experiments are running to compare these features with those of bulk martensite. If the distinction between martensite and bainite is successful, the very high growth rates of the surface laths could be used to discuss the displacive/diffusive nature of bainitic transformations.

Background: Given the rising prevalence of depression among older adults and the associated increase in caregiving responsibilities, understanding factors influencing caregiver burden is crucial. Previous research has not extensively explored the impact of caregivers’ attributional styles, that is, how individuals interpret the causes of life events, on their care burden. Aim: This study examined the relationship between caregivers’ attributional styles and their care burden for older patients with depression. Methods: This cross-sectional study enrolled older adults aged ≥ 65 years diagnosed with depression and their caregivers. Depression was diagnosed according to the DSM-V criteria for Major Depressive Disorder or Persistent Depressive Disorder. Caregivers completed the Chinese Depression Caregiver Burden Scale (CDCBS) to assess care burden, the Hamilton Depression Rating Scale (HAM-D) to evaluate patient symptom severity, the Center for Epidemiological Studies Depression Scale (CES-D) for measuring caregivers’ depression, and the Chinese Depression Patient Caregiver Attribution Style Scale (CDPCAS) to assess attributional styles. Hierarchical regression analysis was used to identify the factors independently associated with the caregiver’s subjectively assessed care burden. Results: The sample included 146 caregivers of geriatric patients with depression. Most depression patients were women (74.7%) with a mean age of 74.3 years, whereas the mean age of caregivers was 57.7 years. Hierarchical regression analysis identified that caregivers’ gender (β= − 0.14, p= .044), educational level (β= 0.19, p= .008), caregivers’ own depression assessed by the Center for Epidemiological Studies Depression Scale (β= 0.41, p< .001), and attributional styles, particularly manipulation (β= 0.29, p< .001) and illness/stress attributional style (β= 0.23, p= .002) as independent factors associated with care burden. Patient symptom severity assessed using the Hamilton Depression Scale was not significantly correlated with care burden after controlling for attributional styles. Conclusions: Certain attributional styles, particularly the manipulation and illness/stress attributional styles, significantly increased self-reported care burden. These findings highlight the need for educational resources to change the attribution style, along with support systems and accessible mental health services for caregivers to potentially ease the care burden.

Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates. The specimens with various nickel contents were adopted for the observation. In the specimen with low fraction of Ni (≤2 wt. %), granular bainite microstructure (i. e. broad surface relief) transformation from intragranular nucleation site was in-situ observed, while, lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni (≥ 4 wt. %). With increasing nickel content, the transformation temperature dropped. The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni. The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix. On account of those observations, not only the chemical component, cooling rate and microstructure were systematically correlated, but also the microstructural evolution was definite.

Ion acoustic waves (IAWs) in an electron-positron-ion (EPI) plasma are studied as affected by various plasma parameters, e.g., electron density, ion temperature, cold ion cyclotron frequency, nonextensive and nonthermal parameters. Plasma fluid equations have been applied to study the plasma system for which reductive perturbation method (RPM) and small-kexpansion method are used to derive the relevant ZK and modified ZK (mZK) equations and the instability growth rate of IAWs, respectively. The effects of nonextensive and nonthermal parameters, external magnetic field, ion-electron temperature ratio and electron density on the dispersion relation, amplitude and width, energy and multi-dimensional instability of IAWs have been shown. It is found that the dispersion relation increases with the increasing nonthermality parameter, but decreases with the increasing nonextensivity parameter. Increasing nonextensive parameter leads to the decreasing soliton energy and the increasing growth rate. Increasing nonthermal parameter leads to the decreasing growth rate. These results will be helpful in the determination of plasma dynamics for electron-positron-ion plasma systems containing Cairns-Tsallis distributed electrons and positrons in interstellar.

Optogenetics has emerged as a revolutionary technology especially for neuroscience and has advanced continuously over the past decade. Conventional approaches for patterned in vivo optical illumination have a limitation on the implanted device size and achievable spatio-temporal resolution. In this work, we developed a fabrication process for a microfiber array platform. Arrayed poly(methyl methacrylate) (PMMA) microfibers were drawn from a polymer solution and packaged with polydimethylsiloxane (PDMS). The exposed end face of a packaged microfiber was tuned to have a size corresponding to a single cell. To demonstrate its capability for single cell optogenetics, HEK293T cells expressing channelrhodopsin-2 (ChR2) were cultured on the platform and excited with UV laser. We could then observe an elevation in the intracellular Ca^2+ concentrations due to the influx of Ca^2+ through the activated ChR2 into the cytosol. The statistical and simulation results indicate that the proposed microfiber array platform can be used for single cell optogenetic applications.

The wetting of galvanized steel by molten Al alloys was studied in the cold metal transfer process by the sessile drop method using a high speed video camera. The wetting behavior can be divided into two typical cases, trending of non-wetting by using small wire feeding speed and wetting by using large wire feeding speed. The Leiden-frost effect is caused by the volatilization of Zn, which is responsible for the former case. The enhanced wettability of steel by Al and the weakening of the Leidenfrost effect are responsible for the latter case. Zn is the destabilizing factor for Al-steel joining that needs to be avoided by a reasonable design of process.

Short-term load forecasting (STLF) plays a very important role in improving the economy and security of electricity system operations. In this paper, a hybrid STLF method is proposed based on the improved ensemble empirical mode decomposition (IEEMD) and back propagation neural network (BPNN). To alleviate the mode mixing and end-effect problems in traditional empirical mode decomposition (EMD), an IEEMD is presented based on the degree of wave similarity. By applying the IEEMD method, the nonlinear and nonstationary original load series is decomposed into a finite number of stationary intrinsic mode functions (IMFs) and a residual. Among these components, the high frequency (namely IMF1) is always so small that it has little contribution to model fitting, while it sometimes has a great disturbance for the STLF. Therefore, the IMF1is removed in the proposed hybrid method for denoising. The remaining IMFs and residual are forecast by BPNN, and then the forecasting results of each component are combined with BPNN to obtain the final predicted load series. Three groups of studies were done to evaluate the effectiveness of the proposed hybrid method. The results show that the proposed hybrid method outperforms other methods both mentioned in this paper and previous studies in terms of all the three standard statistical indicators considered in this study.

A nonlinear dynamic model of a two-span rotor system is constructed based on the Hamilton principle and the finite element method. The Musznyska model and the short bearing model are employed to describe the nonlinear seal force and oil-film force. The fourth-order Runge-Kutta method is used to calculate the numerical solutions. The bifurcation diagrams, time-history diagrams, phase trajectories, and Poincare maps are presented to analyze the dynamic behavior of the bearing center and the disk center in the horizontal direction. The numerical results indicate that the rotational speed, the nonlinear seal force, the oil-film force, and the stiffness of the coupling have a significant effect on the stability of the rotor system. The dynamic behavior of the two-span rotor system is more complicated when impacted by the nonlinear seal force and oil-film force.

All steel laser welded sandwich plates have found their position in the marine and land vehicles. To implement such design accurately, knowledge about its strength properties and the influence of laser weld dimensions on strength is necessary. In this paper, the over-hanging three point bending tests were conducted on the laser welded web-core steel sandwich plate with various weld dimensions by self-designed device, together with the finite element simulations. The results show that the joint is formed on the first plastic hinge when the load is no longer a linear relationship with the deflection, and the joint cracking when the load reaches the maximum bearing capacity of sandwich plate. The joint yield load and the maximum bearing capacity of the sandwich plates increased with the increasing of weld width. Meanwhile, the mode of failure of sandwich plates also changed: When the weld width is smaller, the mode of failure is joint yield, When the weld width is greater than 3mm, the mode of failure is the combination of partial joint yield, face plate and core plate local yield, while the face plate and core plate yield exists in the whole weld joint. It is necessary to consider the weld width in the design and evaluation of the strength of the laser welded web-core sandwich plate.

The carbapenemases have recently emerged as molecules implicated in one of the most feared bacterial resistance mechanisms because of their ability to hydrolyze virtually all lactamase agents and their highly mobile genes. This study aimed to investigate the prevalence of carbapenemase and antimicrobial susceptibilities of Pseudomonas aeruginosaisolated from burn patients in Chongqing, China. Antimicrobial susceptibility of 111 isolates was determined by the disc agar diffusion test and the agar dilution method. Random Amplification of Polymorphic DNA polymerase chain reaction analysis revealed 111 P. aeruginosa42 genotypes. Carbapenemase genes were amplified by polymerase chain reaction and the sequence verified by blast. Ninety-three of 111 (83.8%) isolates were resistant to imipenem; all of them had developed multidrug resistance and exhibited higher resistant rates compared with the imipenem-susceptible Pseudomonas. Ciprofloxacin was the most effective antipseudomonal agent. Thirty-three of the isolates were identified to contain the metallo-ß-lactamase blaIMP-4 gene and belong to different Random Amplification of Polymorphic DNA polymerase chain reactiongenotypes. In conclusion, the high prevalence of multidrug resistance (94.6%) and the production of blaIMP-4 genes in P. aeruginosaisolates in burn patients highlight the necessity of considering these issues in burn hospitals.

Ultrahigh vehicle detection system has been designed which is based on infrared sensor. In application of optical modulation & demodulation, the hardware-circuit is successfully designed by sunlight interference concern. Because of scattering properties of infrared light, software design which is applied of overlapping interference uses algorithm of pulse delay& separation. The later algorithm can well solve the measurement errors of hollow objects, which is basically opposite to the former one, but it costs scan time much more while gets lower efficiency in dynamic measurements of vehicle. The accuracy of this system is 5cm which ranges from 4m to 6m in actual test. The velocity of vehicle can reach 30km/h on the basis of the pulse delay algorithm and 18km/h with the pulse separation algorithm.

The CLUE-S model is a widely used method in the aspect of spatial simulation. CLUE-S model to simulate the land use space pattern of Nanchang in 2005, and compare the simulated results with the land use status figure of Nanchang in 2005 was built on the basis of taking Nanchang as research region, analyzing the land use data of Nanchang in 1995 based on GIS technology, combining natural and social economic factors such as railway, highway, river, settlements, DEM, slope, aspect, etc. and filtering decisive driving factors to the spatial change of Nanchang’s main land use types with SPSS Logistic regression analysis. In the basic unit of 150M*150M grid level, KAPPA index reaches 0.870, the experimental result is ideal. At the same time, predicting the land use pattern of the year 2017 is based on the land use data of Nanchang in 2005. Experimental results indicate that CLUE-S model has good predicting ability to urban spatial structure development, and has reference value to driving mechanism research of the urban layout and analyzing urban development.

A method of mixed gas quantitative analysis with near infrared spectroscopy （NIR）is described. A single plane diffraction grating is used in the monochromatic spectrum system. A quantitative analysis system is designed and constructed according to the parameters of the monochromator. The narrowband beam testing and spectral scanning experiments with methane and ethane are carried out. A 10nm narrowband beam is successfully obtained by the monochromatic system when the entrance slit width is 2mm. And a step-scanning resolution of the outgoing beam’s centre wavelength with 0.1nm can be realized within the spectra of 1.0-1.8μm. The results show that methane and ethane have a maxim characteristic absorption spectrum respectively with the centre wavelength of 1653nm and 1690nm existing between the spectra of 1.6-1.8μm, which is consistent with the HITRAN database. Presented approach has a successful application in online mixed gas monitoring with the characteristics of simple structure and low cost.

Malfunctioned gap junctional intercellular communication (GJIC) has been thought associated with malignant transformation of normal cells. However, the role of GJIC‐related proteins such as connexins in sustaining the malignant behavior of cancer stem cells remains unclear. In this study, we obtained tumorspheres formed by glioma stem cells (GSCs) and adherent GSCs and then examined their GJIC. All GSCs showed reduced GJIC, and differentiated glioma cells had more gap junction‐like structures than GSCs. GSCs expressed very low level of connexins, Cx43 in particular, which are key components of gap junction. We observed hypermethylation in the promoter of gap junction protein α1, which encodes Cx43 in GSCs. Reconstitution of Cx43 in GSCs inhibited their capacity of self‐renewal, invasiveness, and tumorigenicity via influencing E‐cadherinand its coding protein, which leads to changes in the expression of Wnt/β‐catenin targeting genes. Our results suggest that GSCs require the low expression of Cx43 for maintaining their malignant phenotype, and upregulation of Cx43 might be a potential strategy for treatment of malignant glioma. STEMCELLS2012; 30:108‐120.

Nowadays P2P is the premier data distribution technology which tops Internet traffic flow chart. It becomes more and more important to optimize the data flow of P2P traffic. However, there is no general standard for measuring which data distribution scheme is better. A network expense model is proposed for this purpose. By observing the data flows which are produced by P2P, we can calculate the network expense of any data distribution scheme. Now there is a unified standard for evaluating the influence of different data distribution schemes to the network. According to this model, the network expense of a few typical P2P data distributions scheme over the Internet is calculated. Judging from the results, a topology-aware P2P can generate more balanced flows to save the bandwidth of backbone network. Network expense model provide a fundamental tool for optimizing the P2P data distribution.

In this study a new dynamic model of a rotor system is established based on the Hamilton principle and the finite element method (FEM). We analyze the dynamic behavior of the rotor system with the coupled effects of the nonlinear oil film force, the nonlinear seal force, and the mass eccentricity of the disk. The equations of the motion are solved effectively using the fourth order Runge-Kutta method in MATLAB. The dynamic behavior of the system is illustrated by bifurcation diagrams, largest Lyapunov exponents, phase trajectory diagrams, and Poincaré maps. The numerical results show that the rotational speed of the rotor, the pressure drop in the seal, the seal length, the seal clearance, and the mass eccentricity of the disk are the key parameters that significantly affect the dynamic characteristics of the rotor system. The motion of the rotor system exhibits complex types of periodic, quasi-periodic, double-periodic, multi-periodic, and chaotic vibrations. This analysis can be used to guide the design of seal parameters and to diagnose the vibration of rotor/bearing/seal systems.

This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment (TUC) problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modern power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm (IA) is used as the initial solution of the tabu search (TS) algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry.

A small population of stem cell-like precursors in solid tumors are linked to histological composition, progression, angiogenesis, metastasis, recurrence and drug resistance of a variety of malignant tumors. Oligoastrocytoma is the most common brain mixed glioma composed of mixed cells of oligodendroglial and astrocytic phenotypes. Identification and characterization of stem cell-like precursors in oligoastrocytoma may shed light on the oncogenesis of this unique type of tumor and assist in the design of novel therapeutic strategy. Here, tumor stem cell-like precursors were identified from primary human anaplastic oligoastrocytomas by labeling of the tumor sections with nestin and CD133. Tumor cells were cultured in vitro in stem cell medium with growth factors and the capacity of the surviving stem cell-like precursors to form tumor spheres was tested. The tumor spheres were further injected subcutaneously into nude mice to observe the contribution of stem cell-like precursors to histological composition and tumor progression. We found that primary human oligoastrocytoma tissues contained nestin+/CD133+stem cell-like precursors. These cells differentiated into tumor cells with both oligodendroglial and astrocytic characteristics and formed tumor spheres in vitro, which upon implantation in nude mice, grew into tumor nodules containing nestin +/CD133+cells at levels higher than in the primary tumor tissues. This study revealed for the first time that anaplastic human oligoastrocytomas contained stem cell-like precursors, which exhibit neural stem cell properties with tumorigenicity. These stem cell-like precursors may be responsible for the oligodendroglial and astrocytic components of human oligoastrocytoma and should be considered as therapeutic targets.Modern Pathology (2007) 20, 1061–1068; doi:10.1038/modpathol.3800942; published online 27 July 2007

In order to study the damage mechanism under different stress states of aluminum alloy components, two kinds of representative triaxial stress states were adopted, namely notch tensile and pure shear. The results of study showed: During the notch tensile test, stress triaxiality in the least transverse-section was relatively higher. With increasing applied stress, the volume fraction of the microvoid in notch root was increasing constantly. When microvoid volume fraction reached the critical value, the specimen fractured. During the pure shear test, stress triaxiality almost came up to zero, and there was almost no micro-void but localized shear bands within the specimen. The shear bands resulted from non-uniform deformation constantly under the shear stress. With stress concentrating, the cracks were produced in the shear bands and later coalesced. When the equivalent plastic strain reached the critical value, the specimen fractured. The modified Gurson damage model and the Johnson-Cook model were used to simulate the notch tensile and shear test respectively. Simulated engineering stress-strain curves fit the measured engineering stress-strain curves very well. In addition, the empirical damage evolution equation for the notch specimen was obtained from the experiment data and FEM simulations.

Combining in-situ tensile tests with detailed observations of fracture surfaces of a two-phase TiAl alloy, the fracture process and fracture mechanisms of TiAl alloys are investigated. The results reveal that Cracks prefer to initiate and propagate along lamellar interfaces, which are the weakest link in the near fully lamellar microstructure. The interlamellar strength calculated is less than the translamellar strength. The tensile stress is the driving force for crack initiation and propagation. In specimens with a slit notch, most cracks are initiated directly from the notch root and extended along lamellar interfaces. The main crack can be stopped or deflected into a delamination mode by a barrier grain with a lamellar interface orientation deviated from the direction of crack propagation. In this case, new cracks are nucleated along lamellar interfaces of grains with favorable orientation ahead the barrier grain. The main crack and a new crack are then linked by the translamellar cleavage fracture of the barrier grain with increasing applied load. In order to extend the main crack, further increases of the applied load are needed to move the high stress region into the ligament until final fracture. The process of a new crack nucleation with a bridging ligament formation decreases the crack propagation resistance rather than increases it.

Not Available

Fracture behavior of fully lamellar (FL) and duplex phase (DP) TiAl alloys is reported in this paper. It was found that the inverse behavior of coarse FL TiAl alloy showing inferior tensile properties but superior fracture toughness resulted from the different fracture mechanisms of these two types’ tests. In tensile specimens, the final fracture happened at a section that was most heavily damaged by the accumulation of large interlamellar microcracks and arbitrarily located within the gauge-limited volume. In 3PB notch specimens, the propagation of the main crack was constrained within a narrow strip nearby the centerline where the normal stress was the highest. Large lamellar grains caused serious damage in tensile tested specimens. However multi-oriented large lamellar grains formed seriously bifurcated crack tips, which made the crack propagation more difficult in 3PB notched specimen. The main mechanisms of toughening in FL specimens were the deflection of main crack, bifurcation and blunting of crack tip and formation of a diffuse zone of microcracks. These phenomena reduced the driving force for crack extending and then increased the fracture toughness.

This paper uses the small punch test (SPT) to some performance of the materials, have put forward basic method to test the material tensile mechanics performance from an inverse FE method with SPT. The research shows that some tensile mechanics performance and stress of each district of welding seam can be accurate determined by small punch test. This research has offered the theoretical foundation for characterizing of the welded joint with mechanical heterogeneity

A mixed fractional–fractional version of Black–Scholes model with Hurst exponents varying in (0,1) is established, and the corresponding Itoˆ's formula is obtained. The option pricing formulas with Hurst exponents being in (1/3,1) are derived. [Copyright &y& Elsevier]

Not Available

As for fuzzy closed loop control systems composed of fuzzy relation de scribed process and controller this paper proposes an analytical method for the stability of fuzzy closed loop control systems using fuzzy relations and a design method for constructing a stable fuzzy controller As a result the paper develops the theory of fuzzy control systems Examples are given to illustrate how to use the method for the analysis and design of fuzzycontrol systems

An aqueous base-soluble polyimide (BAPAF/6FDA) was obtained from the polycondensation of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BAPAF) and 4,4'-(hexafluoroisopropylidene)–bis(phthalic anhydride (6FDA). It exhibits high thermal stability and high transparency at 365 nm. A novel positive photoresist was prepared by protecting BAPAF/6FDA with a trimethylsilyl group while using diazonaphthoquinone as the photosensitizer. In addition, the silylated polyimide was converted to aqueouse base-soluble polyimide in the presence of an acid and a slight amount of water. This photoresist yields a sensitivity of 110 mJ/cm² and a contrast of 3.24. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 67:1313–1318, 1998

We report a rare mutation on the α2-globin gene, HBA2: c.91_93delGAG and its potential functions.

We investigate the stability of the memory state of the silica-nanoparticle-doped hybrid aligned nematic (SN-HAN) cell. The memory stability of the cell is attributed to the employed planar substrate, which is coated with a homogeneous polyimide (H-PI) film. A H-PI film with a low H-PI solid concentration gives the cell high memory stability. This is because the low H-PI solid concentration causes the film to have a high polar surface energy, trapping polar silica nanoparticles on the planar substrate tightly. The low H-PI solid concentration also gives the substrate a bumpy surface, which has a large surface area for trapping silica nanoparticles.

We investigate the switching characteristics of a silica nanoparticle-doped dual-mode liquid crystal (LC) display. In the multistable mode, aggregated silica networks impede the relaxation of LCs and increase the response time of the cell. A low-frequency AC pulse voltage rotates LCs and breaks aggregated silica networks. The breaking of silica networks accelerates the relaxation of LCs and hence decreases the response time of the cell. The low-frequency AC pulse voltage gives the cell a fast response time of ${\sim}23$ ms, which is ${\sim}4$% of our previous result.