Key Parameters for Strength Control of Artificially Cemented Soils

Often, the use of traditional techniques in geotechnical engineering faces obstacles of economical and environmental nature. The addition of cement becomes an attractive technique when the project requires improvement of the local soil. The treatment of soils with cement finds application, for instance, in the construction of pavement base layers, in slope protection of earth dams, and as a support layer for shallow foundations. However, there are no dosage methodologies based on rational criteria as exist in the case of the concrete technology, where the water/cement ratio plays a fundamental role in the assessment of the target strength. This study therefore aims to quantify the influence of the amount of cement, the porosity and the moisture content on the strength of a sandy soil artificially cemented, as well as to evaluate the use of a water/cement ratio and a voids/cement ratio to assess its unconfined compression strength. A number of unconfined compression tests, triaxial compression tests, and measurements of matric suction were carried out. The results show that the unconfined compression strength increased linearly with the increase in the cement content and exponentially with the reduction in porosity of the compacted mixture. The change in moisture content also has a marked effect on the unconfined compression strength of mixtures compacted at the same dry density. It was shown that, for the soil-cement mixture in an unsaturated state (which is usual for compacted fills), the water/cement ratio is not a good parameter for the assessment of unconfined compression strength. In contrast, the voids/cement ratio, defined as the ratio between the porosity of the compacted mixture and the volumetric cement content, is demonstrated to be the most appropriate parameter to assess the unconfined compression strength of the soil-cement mixture studied.     

Effects of repeated practice and contextual-writing experiences on college students' writing skills.

The authors examined the effects of both general and task-specific writing experiences on college students' writing-skill development. On the basis of theories of expertise development and a cognitive process theory of writing-skill development, the authors predicted that repeated practice would be associated with superior writing skills and that after controlling for repeated practice, writing within a specific task domain would be associated with superior writing skills. Undergraduate students participated in a field experiment in which 279 students practiced their writing skills in a professionally relevant task domain, whereas another group of 385 students practiced their writing skills in a more general domain. The results were consistent with the predictions. The authors discuss implications for teaching writing skills and for general theories of expertise development in writing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Zirconium oxide nanotube surface prompts increased osteoblast functionality and mineralization

Electrochemical formation of tunable nanoscale oxide layers on biomedical metallic surfaces has recently drawn much attention in biomaterials research. In this study, we report on the cellular response to a unique vertically aligned, laterally spaced nanotube nanostructure made of zirconium oxide (ZrO₂) fabricated by anodization. The growth, morphology, and functionality of osteoblasts cultured on ZrO₂ nanotubes have been investigated. The initial adhesion and spreading was considerably improved on the nanotube surface as compared to a flat zirconium (Zr) surface without a nanostructure. The morphology of the adhered cells on the nanotube surface elicited a highly organized cytoskeleton with crisscross patterned actin, which was lacking on the flat Zr. Increased alkaline phosphatase activity levels and the formation of calcified extracellular matrix implied improved osteoblast functionality and mineralization on the nanotube substrate. This in vitro study suggests that the ZrO₂ nanotubes provided an enhanced osteoblast response and demonstrated their apparent role in providing a platform for bone growth.     

Effects of a Corneal Anesthetic on Extinction of the Classically Conditioned Nictitating Membrane Response in the Rabbit (Oryctolagus cuniculus).

Rabbits (Oryctolagus cuniculus) were presented with 7 daily sessions of tone-alone training after conditioning. Before the beginning of each of the first 4 extinction sessions, an artificial tear solution or tetracaine hydrochloride was administered to the cornea of rabbits in the control group (n=6) and experimental group (n=1), respectively. There were no between-group differences in the percentage of conditioned responses between both groups. However, the amplitude of the conditioned response was notably reduced in the tetracaine group (M=0.40, SEM±0.216) relative to the control group (M=1.32, SEM ±0.639) early in extinction. Results seem to suggest that although motor output has been found to play an important role in extinction, corneal sensory feedback is not necessary. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structure of maladaptive personality traits in childhood: A step toward an integrative developmental perspective for DSM-V.

The present study describes the construction of a taxonomy of trait-related symptoms in childhood, the Dimensional Personality Symptom Item Pool (DIPSI), and examines the replicability of the taxonomy's higher order structure across maternal ratings of referred (N = 205) and nonreferred (N = 242) children and self-ratings of adolescents (N = 453). The DIPSI's 4 higher order factors--that is, Emotional Instability, Disagreeableness, Introversion, and Compulsivity--showed clear correspondence with the dimensions of personality pathology found in adulthood (Dimensional Assessment of Personality Pathology-Basic Questionnaire; W. J. Livesley, 1990; Schedule for Nonadaptive and Adaptive Personality; L. A. Clark, 1993). These 4 factors can be further organized into 2 superfactors, representing Internalizing and Externalizing Traits, demonstrating empirical and conceptual relationships with psychopathology models in childhood and adulthood. The implications for the assessment and conceptualization of early trait pathology are discussed in the context of an integrative developmental perspective on the construction of the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Empirically supported treatments: Implications for training.

This article discusses the role of empirically supported treatments (ESTs) in the training of clinical psychologists. Training in ESTs can be integrated in ways that vary depending on the level of training and setting. Predoctoral programs, internships, postdoctoral programs, and continuing education are discussed in regard to special challenges and sequencing of training. A preliminary set of guidelines for training in ESTs is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predatory behavior in laboratory mice: Strain and sex comparisons.

Measured latency to attack live crickets in 26 male and 26 female naive, non-food-deprived laboratory mice from a genetically heterogenous stock (HS/Ibg) and in 7 inbred strains (10 male and 10 female Ss for each strain). The HS/Ibg, Is/Crgl, C57BL/Crgl, and C3H/Crgl Ss had the shortest latencies to attack crickets. The RIII/Crgl and BALB/cCrgl Ss were intermediate, while DBA/2Crgl and A/Crgl were slowest. Among the inbred strains sex differences were nonexistent or inconsistent from strain to strain. However, HS/Ibg males were more likely to attack than were females. Enough females attack for cricket killing to be a useful form of attack behavior for genetic experiments. In nearly all Ss latency decreased from the 1st to the 2nd trial, indicating that cricket killing is rapidly learned in adult mice of a wide variety of genotypes. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Survival of Lactobacillus casei (LC-1) adhered to prebiotic vegetal fibers

This study evaluated the survival of Lactobacillus casei (LC-1) when adhered to four different dehydrated prebiotic fibers. After vacuum drying in oat bran with 9% β-glucan and green banana flour, LC-1 viability was 79% and 76%, respectively. Scanning electron microscopy images revealed no morphological changes in the cells adhered to these fibers, and the addition of trehalose as a cell protectant had a positive and significant effect on the survival of LC-1. At different storage temperatures, oat bran had the highest stability as well as in simulated gastrointestinal conditions, where LC-1 that adhered to the oat bran had greater viability (7.1 log CFU g^? 1) than in the free form (2.4 log CFU g^? 1). In the sensory evaluation, the probiotic oat bran added to a dairy fruit beverage was well accepted by consumers.Industrial relevanceThe diversification of food products and the growing interest in health life requires from food industry innovations and new products for this. Probiotic cultures into non-dairy products is still an innovation and a challenge to the functional food segment. The development of an oat bran with LC-1 adhered is important for the functional food industries because the probiotic can be viable during dehydration and storage at room temperature. In addition the LC-1 is protected under simulated gastrointestinal conditions without compromising sensory acceptability.     

A Microfluidic 3D Endothelium-on-a-Chip Model to Study Transendothelial Migration of T Cells in Health and Disease

The recruitment of T cells is a crucial component in the inflammatory cascade of the body. The process involves the transport of T cells through the vascular system and their stable arrest to vessel walls at the site of inflammation, followed by extravasation and subsequent infiltration into tissue. Here, we describe an assay to study 3D T cell dynamics under flow in real time using a high-throughput, artificial membrane-free microfluidic platform that allows unimpeded extravasation of T cells. We show that primary human T cells adhere to endothelial vessel walls upon perfusion of microvessels and can be stimulated to undergo transendothelial migration (TEM) by TNFα-mediated vascular inflammation and the presence of CXCL12 gradients or ECM-embedded melanoma cells. Notably, migratory behavior was found to differ depending on T cell activation states. The assay is unique in its comprehensiveness for modelling T cell trafficking, arrest, extravasation and migration, all in one system, combined with its throughput, quality of imaging and ease of use. We envision routine use of this assay to study immunological processes and expect it to spur research in the fields of immunological disorders, immuno-oncology and the development of novel immunotherapeutics.     

Histological Evaluation and Gene Expression Profiling of Autophagy-Related Genes for Cartilage of Young and Senescent Rats

Autophagy is a cellular mechanism that protects cells from stress by digesting non-functional cellular components. In the cartilage, chondrocytes depend on autophagy as a principal mechanism to maintain cellular homeostasis. This protective role diminishes prior to the structural damage that normally occurs during aging. Considering that aging is the main risk factor for osteoarthritis, evaluating the expression of genes associated with autophagy in senescent cartilage might allow for the identification of potential therapeutic targets for treatment. Thus, we studied two groups of young and senescent rats. A histological analysis of cartilage and gene expression quantification for autophagy-related genes were performed. In aged cartilage, morphological changes were observed, such as an increase in cartilage degeneration as measured by the modified Mankin score, a decrease in the number of chondrocytes and collagen II (Col2a1), and an increase in matrix metalloproteinase 13 (Mmp13). Moreover, 84 genes associated with autophagy were evaluated by a PCR array analysis, and 15 of them were found to be significantly decreased with aging. Furthermore, an in silico analysis based on by two different bioinformatics software tools revealed that several processes including cellular homeostasis, autophagosome assembly, and aging—as well as several biological pathways such as autophagy, insulin-like growth factor 1 (IGF-1) signaling, PI3K (phosphoinositide 3-kinase)/AKT (serine/threonine kinase) signaling, and mammalian target of rapamycin (mTOR) signaling—were enriched. In conclusion, the analysis identified some potential targets for osteoarthritis treatment that would allow for the development of new therapeutic strategies for this chronic disease.