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Vegetation restoration is the primary strategy employed for the purification and restoration of habitats in the Zhegao River wetlands. To investigate the changing characteristics of soil microbial biomass carbon/nitrogen (MBC/MBN) and soil enzyme activities in wetlands undergoing different vegetation restoration treatments, those involving reed and willow restoration were studied in 2014 (WR8) and 2021 (WR1), with a native vegetation wetland (NW) used as a control. This study examined changes in the MBC/MBN, sucrase (Suc), urease (Ure), and acid phosphatase (Acp) in these wetlands. The results indicated that during the restoration of Zhegao River wetlands, reed vegetation had a stronger positive effect on soil properties after one year of restoration than that of willow vegetation. After eight years, the effects of willow vegetation restoration were greater than those of reed vegetation restoration. The activities of MBC, MBN, Suc, Ure, and Acp in the reed and willow wetland soils for different years of vegetation restoration decreased with greater soil depth. Thus, reeds and willows have distinct contributions toward enhancing the ecological service functions of the Zhegao River wetlands for different restoration years, which provides a scientific basis for the selection and protection of ecological wetland restoration. [ABSTRACT FROM AUTHOR]

Explosive devices represent a significant threat to military and civilian structures. Specific design procedures have to be followed to account for this and ensure buildings will have the capacity to resist the imposed pressures. Shrapnel can also be produced during explosions and the resulting impacts can weaken the structure, reducing its capacity to resist the blast pressure wave and potentially causing failures to occur. Experiments were performed by the Defence Science and Technology Agency (DSTA) of Singapore to study this combined loading phenomenon. Slabs were placed on the ground and loaded with approximately 9 kg TNT charges at a standoff distance of 2.1 m. Spherical steel ball bearings were used to reproduce the shrapnel loading. Loading and damage characteristics were recorded from the experiments. A finite element analysis (FEA) model was then created which could simulate the effect of combined shrapnel impacts and blast pressure waves in reinforced concrete slabs, so that its results could be compared to experimental data from the blast tests. Quarter models of the experimental concrete slabs were built using LS-Dyna. Material models available in the software were employed to represent all the main components, taking into account projectile deformations. The penetration depth and damage areas measured were then compared to the experimental data and an analytical solution to validate the models. [ABSTRACT FROM AUTHOR]

In this study, the impact responses of concrete debris against soil are investigated. Three types of concrete debris are shot at soil with different incident conditions in experiments. A numerical modeling for the impact process is established and calibrated by the experimental results. A further study on the effect of debris size is then carried out based on the calibrated numerical modeling. A set of formulation is presented to predict the outgoing velocity and the outgoing angle in terms of the incident velocity and the incident angle. Critical lethality curves are derived based on the assumption of a critical kinetic energy of 79 J. [ABSTRACT FROM AUTHOR]

The boundary finite-element method (BFEM) is extended for steady-state analyses of dam-reservoir system problems. In this study, the dam is assumed to be rigid and subjected to horizontal ground motions, and the liquid in the reservoir is assumed to be semiinfinite. The semiinfinite reservoir domain is partitioned into two subdomains: a near-field domain and a far-field domain. In it, the near-field domain is modeled by using the finite-element method (FEM), whereas the far-field domain is modeled by BFEM and is treated as a layered semiinfinite fluid domain. A BFEM/FEM coupling procedure is employed to solve the steady-state response of the reservoir. The coupling procedure is easy to implement and suitable for all frequencies, be it real or complex. The BFEM/FEM coupling procedure is validated in the frequency domain. Numerical results that are based on the present procedure are in good agreement with analytical and other available numerical solutions. [ABSTRACT FROM AUTHOR]

In this paper, the boundary finite element method (BFEM) is applied to dynamic fluid-structure interaction problems. The BFEM is employed to model the infinite fluid medium, while the structure is modeled by the finite element method (FEM). The relationship between the fluid pressure and the fluid velocity corresponding to the scattered wave is derived from the acoustic modeling. The BFEM is suitable for both finite and infinite domains, and it has advantages over other numerical methods. The resulting system of equations is symmetric and has no singularity problems. Two numerical examples are presented to validate the accuracy and efficiency of BFEM-FEM coupling for fluid-structure interaction problems. [ABSTRACT FROM AUTHOR]

To investigate the joint effect on shock wave propagation and attenuation in jointed rock masses, a small-scale field explosion test is analyzed numerically by using the three-dimensional discrete element method (3D DEM) and the three-dimensional finite difference method (3D FDM). Results show that rock joints act as a kind of filter through which only low frequency shock waves are allowed to pass. This indicates that high frequency shock waves do no harm to far-field structures when they have to travel across joint sets with specific spacing. Results also reveal that the orientation of the joint sets can remarkably affect the amplitude and frequency composition of shock waves. Furthermore, as a discontinuous numerical method, 3D DEM can capture the main features of shock waves, and most importantly, it can simulate the 3D effect of rock joints. It can be concluded that in modelling 3D shock wave propagation and attenuation in jointed rock masses, 3D DEM has unique advantages over 2D modeling, 3D FDM, and even field testing. [ABSTRACT FROM AUTHOR]

The stability problem has prevented the application of the boundary element method/finite element method (BEM/FEM) coupling procedure in dynamic fluid-structure interaction problems for the last 2 decades. It has been proved that the linear θ method can make a significant stability improvement for the time domain BEM scheme. With the use of the linear θ method, the BEM/FEM coupling procedure is applied to two-dimensional time domain fluid-structure interaction problems. The fluid domain is acoustic and modeled by taking advantage of the BEM scheme that is suitable to either finite or infinite domains. An internal source has been considered in BEM formulations, and no artificial boundary needs to be introduced for the infinite domain. The structure is modeled by finite elements that can be either linear or nonlinear. Two classical examples are given to show the validity of the coupling procedure in fluid-structure interaction problems and the significant stability improvement given by the linear θ method to the BEM/FEM coupling procedure. [ABSTRACT FROM AUTHOR]

This paper presents the derivation of the governing equations for the stability of vibration of an integrated system comprising a moving train and the railway track. The train consists of a convoy of articulated two-axle wagons. The equations are applicable to any arbitrary number of axles at arbitrary spacing. Each axle is modelled as a mass–spring–damper vibration unit. The railway track is an infinitely long Euler beam subjected to an axial compressive force and rests on a visco-elastic foundation. The governing equations for the integrated system are coupled differential equations, which can be transformed to algebraic equations by Fourier and Laplace transforms. Subsequent inverse Fourier transform and contour integration yield the instability equation. Critical parameter is identified. It follows by parametric studies on the instability of vibration due to different train configurations. Illustrative examples for trains having up to 20 wagons or 40 axles are given. [Copyright &y& Elsevier]

The Gibbs phenomenon in Fourier series has long been recognized as a drawback in its applications, in particular when it is used to represent a function having discontinuities. One category, namely, intrinsic discontinuities, could be derived from the nature of the physical problems. Another, namely, inherent discontinuities, is created undesirably through the employment of Fourier series. To alleviate these drawbacks, two techniques are developed. The first aims at eliminating the inherent discontinuities. The size of the original domain [0, l] is first doubled with a virtual function φ0 defined over the neighboring domain [-l, 0]. The augmented domain [-l, d] is then further extended periodically. The virtual function &phi0(y) is chosen so that continuities are achieved at y = 0, ±l, ±21,.... Consequently, no Gibbs phenomena will occur at the boundaries. The second aims at reproducing the intrinsic discontinuities in the representation function by incorporating piecewise cubic polynomials into the Fourier base function. The enlarged basis function, namely, the Gibbs-phenomenon-free-Fourier-series function, is able to represent accurately any specific boundary conditions and interior intrinsic discontinuous conditions. Examples of vibration and buckling analysis of complex beams show that the present method is versatile, accurate, and efficient. [ABSTRACT FROM AUTHOR]

The current practice of further exploration for other intra-abdominal pathology only upon finding a normal appendix may leave other organic causes of acute abdomen undetected if the surgeons' on-table diagnostic accuracy is low. In this study, surgeons were unable to make an accurate on-table diagnosis in 14.3% of the cases. The sensitivity for diagnosing normal appendixes is also low at 51.3%, suggesting that almost half of the normal appendixes are misdiagnosed as acute appendicitis and without further exploration for other pathology.

We conducted a study in a Chinese Han population to investigate the role of XRCC1 gene polymorphisms (Arg399Gln and Arg194Trp) with a risk of susceptibility to gliomas. Samples from 115 patients with gliomas and 228 control subjects were consecutively collected between March 2012 and December 2014. Genotype analysis of XRCC1 Arg399Gln and Arg194Trp was performed using polymerase chain reaction-restriction fragment length polymorphism assay. All the analyses were performed using the SPSS 17.0 software package. We observed that the XRCC1 Arg399Gln and Arg194Trp genotype frequencies conformed to the Hardy-Weinberg equilibrium. We observed that the Trp/Trp genotype of XRCC1 Arg194Trp was associated with an increased risk of glioma when compared to the wild-type genotype (odds ratio (OR) = 2.14, 95% confidence interval (CI) = 1.14-3.86, P = 0.03). In the dominant model, we found that the Arg/Trp + Trp/Trp genotype of XRCC1 Arg194Trp could significantly elevate the susceptibility of developing glioma (OR = 1.79, 95%CI = 1.07-0.94). However, we observed that the XRCC1 Arg399Gln genetic polymorphism did not influence the risk of glioma. In summary, we suggest that the XRCC1 Arg194Trp genetic polymorphism could be a predictive biomarker for the susceptibility to glioma in a Chinese population., Competing Interests: The authors declare no conflict of interest.

The present study is designed to investigate the role of peroxisome proliferator-activated receptors delta (PPARdelta) in the action of digoxin in diabetic rats showing cardiac hypertrophy. We used Wistar rats to induce diabetes by injection of streptozotocin (STZ-rat) and examined the effect of digoxin on PPARdelta expression in these hyperglycemic rats (STZ-rat) at 10 weeks later. We measured the changes of body weight, water intake, and food intake in three groups of age-matched rats; the vehicle treated normal control (Wistar rats), the vehicle treated STZ-rats, and the digoxin-treated STZ-rats. Cardiac output, heart rate, and blood pressure in addition to plasma insulin or glucose level were also determined. The mRNA and protein levels of PPARdelta were measured using Northern and Western blotting, respectively. Cardiac output, heart rate, and blood pressure were markedly reduced while food intake, water intake, and blood glucose were raised in STZ-rats showing lower body weight and plasma insulin as compared with the vehicle-treated controls. After a 20-day of digoxin treatment, cardiac output was raised in STZ-rats but the diabetic parameters were not modified. The PPARdelta expressions, both mRNA and protein, were markedly elevated in the hearts of STZ-rats by digoxin treatment. The related signals with PPARdelta, such as carnitine palmitoyltransferase 1B (CPT1B), acetyl-coenzyme A, carboxylase alpha (ACC1), fatty acid synthase (FAS), and troponin I, were also raised. The increase of cardiac output by digoxin was reversed by the combined treatment with PPARdelta antagonist GSK0660. Thus, we suggest a new finding that PPARdelta is involved in digoxin induced cardiac inrotropic action., (Copyright Georg Thieme Verlag KG Stuttgart New York.)

To investigate the association between plasma leptin and adiponectin and insulin sensitivity in children, 580 school children (294 boys and 286 girls) with mean age of 13.3 years (12-16 years) were randomly selected from the Taipei Children Heart Study. Baseline measurements included body weight, body mass index (BMI), plasma glucose, insulin, proinsulin, leptin and adiponectin levels. Insulin resistance and beta-cell function were assessed using the method of homeostatic model, HOMA-IR and HOMA-beta, respectively. We found that girls had higher levels of plasma leptin, adiponectin and HOMA-beta than boys. There was no significant difference in HOMA-IR between boys and girls. Plasma leptin concentrations were positively correlated with body weight, BMI, insulin and proinsulin concentrations, HOMA-IR and HOMA-beta, whereas plasma adiponectin levels were inversely associated with body weight, BMI and proinsulin levels in both sexes. In girls, adiponectin concentrations were negatively correlated with insulin concentration and HOMA-IR. In multiple regression analyses, plasma leptin was more positively associated with insulin and proinsulin levels, HOMA-IR and HOMA-beta than was adiponectin in boys. This association persisted even after adjusting for body weight, BMI and pubertal status. In conclusion, plasma leptin was more strongly associated with insulin sensitivity and beta-cell function than was adiponectin among children, particularly in boys.

In this paper, we demonstrate that the spinal vertebral body (VB) remodels (as per Wolf's law) such that its shape and dimensions enable it to be a light-weight high-strength structure. The VB is modeled as a hyperboloid shell, whose generators are shown to sustain (and transmit) all the loadings on the VB as axial forces. Upon minimizing the sum of the forces in the hyperboloid VB generators with respect to its shape parameters theta (the angle between pairs of generators), we obtain the optimal shape-dimensions of the VB which corresponds to its measured shape-dimensions. This parameter theta is deemed to be the prime shape parameter of the hyperboloid VB.

A new insertion sequence (IS), IS1405, was isolated and characterized from a Ralstonia solanacearum race 1 strain by the method of insertional inactivation of the sacB gene. Sequence analysis indicated that the IS is closely related to the members of IS5 family, but the extent of nucleotide sequence identity in 5' and 3' noncoding regions between IS1405 and other members of IS5 family is only 23 to 31%. Nucleotide sequences of these regions were used to design specific oligonucleotide primers for detection of race 1 strains by PCR. The PCR amplified a specific DNA fragment for all R. solanacearum race 1 strains tested, and no amplification was observed with some other plant-pathogenic bacteria. Analysis of nucleotide sequences flanking IS1405 and additional five endogenous IS1405s that reside in the chromosome of R. solanacearum race 1 strains indicated that IS1405 prefers a target site of CTAR and has two different insertional orientations with respect to this target site. Restriction fragment length polymorphism (RFLP) pattern analysis using IS1405 as a probe revealed extensive genetic variation among strains of R. solanacearum race 1 isolated from eight different host plants in Taiwan. The RFLP patterns were then used to subdivide the race 1 strains into two groups and several subgroups, which allowed for tracking different subgroup strains of R. solanacearum through a host plant community. Furthermore, specific insertion sites of IS1405 in certain subgroups were used as a genetic marker to develop subgroup-specific primers for detection of R. solanacearum, and thus, the subgroup strains can be easily identified through a rapid PCR assay rather than RFLP analysis.

The mammalian anterior pituitary is known to be regulated by humoral factors only, no direct neural influence having ever been discovered. Our recent studies have shown in several species that there are substantial amounts of substance P and calcitonin-gene-related peptide-like immunoreactive (CGRP-LI) nerve fibers in the anterior pituitary and that they can make synaptic contacts with secretory cells, among which corticotropes. In the present study, we investigated changes in CGRP-LI nerve fibers of the anterior pituitary after bilateral adrenalectomy in the rat. The results show that the number of CGRP-LI nerve fibers increases significantly. In parallel, they cover a wider area of the gland after the operation, suggesting a direct neural influence.

A study of all births in Switzerland during the years 1979-81 is used to illustrate the advantages of the case-cohort design for this epidemiologic analysis of neonatal mortality. The example shows that familiar associations between infant mortality and explanatory variables such as sex and weight at birth can be precisely estimated using only a sample from the full cohort.