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In this study, a combination of acoustic emission (AE) method (AEM) and wave transmission method (WTM) is used to investigate the behaviors of AE and ultrasonic properties corresponding to initial fracturing in granitic rocks. The relationships of AE characteristics, frequency spectra, and spatial locations with crack initiation (CI) are studied. The anisotropic ultrasonic characteristics, velocity distributions in different ray paths, wave amplitudes, and spectral characters of transmitted waves are investigated. To identify CI stress, damage initiations characterized by strain-based method (SBM), AEM and WTM are compared. For granite samples, it shows that the ratio of CI stress to peak strength estimated by SBM ranges from 0.4 to 0.55, and 0.49–0.6 by WTM, which are higher than that of AEM (0.38–0.46). The CI stress identified by AEM indicates the onset of microcracking, and the combination of AEM and WTM provides an insight into the detection of rock damage initiation and anisotropy.

Chemically protected sodium butyrate (CSB) is a new kind of sodium butyrate. Our previous study found that 1,000 mg/kg of CSB had the potential capacity of improving growth performance and promoting early development of small intestine in broilers. This study aimed to investigate the effect of long-term antibiotics or CSB supplementation for intestinal microflora dynamical regulation in broilers. One hundred ninety-two 1-day-old Arbor Acres male broilers were randomly allocated into 3 dietary treatment (8 replicates per treatment) and fed with a basal diet (CON), a diet supplemented with the antibiotics (enramycin, 8 mg/kg and aureomycin, 100 mg/kg) (ANT), or a diet supplemented with 1,000 mg/kg of CSB, respectively. Results showed that dietary supplementation of CSB or ANT treatment elevated the weight gain and feed conversion ratio (FCR; P< 0.05), as compared with control (CON) group. Additionally, CON, CSB, or ANT administration dynamically altered the gut microbiota composition as time goes on. The increased presence of potential pathogens, such as Romboutsiaand Shuttleworthia, and decreased beneficial bacteria such as Alistipes, Akkermansia, and Bacteroideswere verified in new gut homeostasis reshaped by long-term antibiotics treatment, which has adverse effects on intestinal development and health of broilers. Conversely, CSB supplementation could dynamically enhance the relative abundance of Bacteroides, and decrease Romboutsiaand Shuttleworthiain new microflora, which has positive effects on intestinal bacteria of broilers compared with CON group. Meanwhile, CSB supplementation was significantly increased the concentration of propionic acid and total short chain fatty acids (total SCFA; P< 0.05) in comparison with CON and ANT groups. Moreover, CSB treatment significantly increased anti-inflammatory and antioxidative capacities (P< 0.05) of broilers compared with ANT group. Taken together, we revealed characteristic structural changes of gut microbiota throughout long-term CSB or ANT supplementation in broilers, which provided a basic data for evaluating the mechanism of action affecting intestinal health by CSB or ANT administration and CSB as an alternative to antibiotics in the broilers industry.

A new algorithm of phase field model is developed to simulate polycrystalline dendritic solidification growth in undercooled melts. The algorithm adopts a single phase field order parameter model incorporated with the anisotropy of solid-liquid interfacial energy and mobility. The model validation is performed by comparing the simulations with the theory analytical results and experimental information for both single and multi-grain dendritic growth, which demonstrates the quantitative capabilities of the proposed algorithm.

Filtering has been a major technique used in homogenization-based methods for topology optimization of structures. It plays a key role in regularizing the basic problem into a well-behaved setting, but it has the drawback of a smoothing effect around the boundary of the material domain. In this paper, a diffusion technique is presented as a variational approach to the regularization of the topology optimization problem. A nonlinear or anisotropic diffusion process not only leads to a suitable problem regularization but also exhibits strong “edge”-preserving characteristics. Thus, we show that the use of nonlinear diffusions brings the desirable effects of boundary preservation and even enhancement of lower-dimensional features such as flow-like structures. The proposed diffusion techniques have a close relationship with the diffusion methods and the phase-field methods from the fields of materials and digital image processing. The proposed method is described and illustrated with 2D examples of minimum compliance that have been extensively studied in recent literature of topology optimization.

Minimally invasive approaches for lumbar spinal fusion have advanced considerably over the past decade. The underlying goal of these procedures is to perform a successful arthrodesis while minimizing destruction to normal soft tissues. In this manner, it is anticipated that patients will experience a reduction in postoperative pain, improved physiologic muscle function, and better cosmesis when compared with standard open spinal surgery. Contemporary techniques for minimally invasive posterior lumbar pedicle-screw fusion can be categorized as true percutaneous, through a tubular dilator retractor, and muscle splitting. Each of these approaches is associated with specific advantages and drawbacks.

In this paper we present a new framework to approach the problem of structural shape and topology optimization. We use a level-set method as a region representation with a moving boundary model. As a boundary optimization problem, the structural boundary description is implicitly embedded in a scalar function as its “iso-surfaces.” Such level-set models are flexible in handling complex topological changes and are concise in describing the material regions of the structure. Furthermore, by using a simple Hamilton–Jacobi convection equation, the movement of the implicit moving boundaries of the structure is driven by a transformation of the objective and the constraints into a speed function that defines the level-set propagation. The result is a 3D structural optimization technique that demonstrates outstanding flexibility in handling topological changes, the fidelity of boundary representation, and the degree of automation, comparing favorably with other methods in the literature based on explicit boundary variation or homogenization. We present two numerical techniques of conjugate mapping and variational regularization for further enhancement of the level-set computation, in addition to the use of efficient up-wind schemes. The method is tested with several examples of a linear elastic structure that are widely reported in the topology optimization literature.

A series of back-coated cotton fabrics comprising varying molar ratios of chlorine, bromine and antimony has been studied using a simulated match ignition test, LOI and thermal analysis (TGA and DTA).Results show that the presence of chlorine alone and in combination with bro mine increases LOI and carbonaceous char values at optimum halogen :anti mony molar ratios of 2.5-3.6:1 and bromine:chlorine molar ratios within the range 0.31-0.42. Only back-coated samples containing bromine pass the simu lated match test although at Br:Sb molar ratios above 4:1, LOI and char residual values decrease. It is evident that condensed and vapour phase flame retardant mechanisms are operating with efficiencies determined by halogen : Sb and Br/Cl molar ratios. Partial and whole replacement of halogen and antimony by phosphorus-containing and other flame retardants in the back-coating formulation that do not function in the vapour phase may be used to pass the simulated match test.

Background: Carotid stenosis is an important, treatable cause of stroke. Several population-based studies have shown ethnic differences in the prevalence of carotid atherosclerosis. This study was performed at a large multiethnic hospital to clarify these differences. Methods: One thousand six carotid artery ultrasounds performed by the Department of Radiology at Los Angeles County General Hospital over a 4-year period were reviewed. Patients were classified as Caucasian (n=151), Hispanic (n=515), Black (n=173), or Asian (n=167) by self-declaration and birthplace. Carotid stenosis was defined as mild (1% to 39%), moderate (40% to 59%), severe (60% to 79%), critical (80% to 99%), or total (100%). Results: Twenty and one-half percent of Caucasian patients had greater than 59% stenosis compared with 10.1% of Hispanics, 8.7% of Blacks, and 10.7% of Asians (P<0.001). Nine and two-tenths percent of Caucasians had greater than 79% stenosis compared with 4.3% of Hispanics, 2.9% of Blacks, and 2.8% of Asians (P<0.001). There were no significant differences in age or gender representations between ethnic groups, and the indications for ordering carotid duplex sonography also did not vary by race. Caucasians and Blacks had a higher prevalence of cardiac disease, smoking, and heavy alcohol abuse. Hispanics had higher rates of diabetes. Conclusions: These results indicate that significant differences in the degree of carotid stenosis exist among ethnic groups. Caucasian patients in our series showed a statistically higher likelihood of having a severe or critical level of stenosis. These findings may have implications for the allocation of health care resources as ethnic minorities compose a greater proportion of the population

A cDNA, Ch-GT2, encoding a glucose transporter was cloned by screening a chicken liver λgt11 cDNA library and by modified polymerase chain reaction (PCR) techniques. The encoded protein is highly homologous to rat and human GLUT 2. Within the predicted amino acid sequence, there are 12 putative transmembrane helices with a relatively large exofacial hydrophilic loop between transmembrane segments 1 and 2, which is characteristic of mammalian GLUT 2. Expression of Ch-GT2 gene in E. coliresults in sixfold increase in the uptake of 2-deoxy-D-glucose uptake, and this increment can be reduced by incubation with phloretin. Thus, Ch-GT2 is a bona fidechicken liver glucose transporter. A deletion mutant generated by PCR was expressed in bacteria and shown to be functional, indicating that the N-terminal seven amino acid residues of Ch-GT2 is not essential for transport of glucose. From Northern blot analysis, Ch-GT2 is prominently expressed in chicken liver with a transcript of 4.0 kb, but not in chicken brain and heart, suggesting that distinct types of glucose transporters are present in various chicken tissues.

DNA of livers or kidneys of rodents contain endogenously modified nucleotides of as yet unknown structure or function. As part of our examination of the origin of endogenous DNA modifications, we examined polar adducts of hamster liver and kidney DNA by 32P-postlabeling analysis (central and upper cuts) and compared them to adducts generated by incubation of DNA with [9Z,11E,(13S)]-13-hydroperoxyoctadecadienoic acid or with malondialdehyde. The central and upper cuts of DNA adduct maps of intact female retired breeder hamsters contained one and three adducts called C1, U1, U2, and U3, respectively, which cochromatographed with similar adducts in DNA incubated with the hydroperoxide or with malondialdehyde. Concentrations of adducts C1, U1, and U2 in organs of 1-month-old hamsters were lower than those in the 5-month-old female retired breeder hamsters. Adduct concentrations increased in tandem with lipid peroxide concentrations in livers and kidneys of hamsters treated with carbon tetrachloride compared to controls. A linear dependence of the concentrations of adducts on those of lipid peroxides was demonstrated independent of the treatment conditions or the organ examined. The polar endogenous adducts U1, U2, and U3 were identified by cochromatography in five different chromatographic systems with adducts induced by linoleic hydroperoxide or malondialdehyde. Adducts U1, U2, or U3 were also formed by incubating malondialdehyde with dAMP or with dGMP, respectively. The dependence of adduct concentrations in vivoon lipid peroxide levels are taken as evidence that decomposition products of lipid peroxides such as malondialdehyde induced endogenous DNA adducts in intact animals. Moreover, these adducts may mediate carcinogenic processes induced by chemicals which raise lipid peroxide levels.

The particle orbits in field-reversed mirrors (FRM) are studied. It is found that the orbit can be expressed in terms of the first and third kind of elliptic integral for particles moving in the centre plane of the Hill vortex configuration. Requirements for absolute confinement are obtained, and four distinct classes of orbits are identified that are bounded by limits on the canonical angular momentum P?. The improvement in confinement over a simple mirror as well as natural divertor properties of the FRM are illustrated by these results.