Calibration Chamber Studies of Miniature Piezocone Penetration Tests in Cohesive Soil Specimens.

The electronic piezocone penetrometer is potentially a very powerful in-situ testing device used for soil profiling and in the determination of engineering soil properties. The focus of this research is on the laboratory calibration of a miniature piezocone penetrometer in cohesive soil specimens instrumented to monitor the spatial pore pressure distribution. Two automated slurry consolidometers were developed for this research that were successful in preparing homogeneous and reproducible cohesive soil specimens. The results of eight miniature piezocone penetration tests (PCPT) and three miniature quasi-static friction cone penetration tests (QCPT) performed in a flexible double wall calibration chamber system are presented. The influence of soil type, stress history, penetration boundary conditions and filter locations on PCPT data are investigated. The PCPT results are evaluated using some of the existing methods to estimate the undrained shear strength, s\sb{\rm u}; lateral stress coefficient, K\sb{\rm o}; over-consolidation ratio, OCR; and the radial coefficient of consolidation, c\sb{\rm r}. The influence of lateral stress and soil type on the empirical cone factor and the pore pressure factor used to estimate s\sb{\rm u} are investigated. The influence of lateral stress on penetration pore pressures is investigated and the validity of a recent method for K\sb{\rm o}-profiling is verified. The OCR and the K\sb{\rm o} are found to influence the penetration depth required to attain a steady excess pore pressure value. An existing model to predict OCR from PCPT data is modified to include the influence of K\sb{\rm o}. The method is used to evaluate the OCRs of the chamber specimens and its validity is further verified by application to well documented field sites. The need to base the interpretation of c\sb{\rm r} on the initial dissipation values of the excess pore pressure instead of the penetration pore pressure and also the need to include the influence of stress history on the proposed time factors are realized. The importance of the rate of penetration and the pore pressure dissipation that occurs even during piezocone penetration while interpreting dissipation data on the piezocone shaft is recognized

CPT Evaluation of Liquefaction Potential Using Neural Networks

The increasing popularity of the cone penetration test (CPT) for site investigations has led to several methods for predicting liquefaction potential from CPT data. This paper describes a feed-forward neural network model trained by back-propagation for predicting liquefaction potential. The model requires the following seven input variables: cone resistance, total vertical stress, effective vertical stress, earthquake magnitude, maximum horizontal acceleration at ground surface, the mean grain size D50, and the seismic shear-stress ratio. A total of ninety-six data sets from different sites around the world were used for training, and eighty-two data sets were used for testing and validating the neural network model. The model gave an overall success rate of 96% for correctly predicting the liquefaction potential

Effects of Prenatal Drug Exposure on Adolescent Brain Activation During a Visuospatial Working Memory Task

Background: Previous research examining effects of prenatal drug exposure (PDE) has yielded mixed results regarding cognitive performance during school age years. Associations between PDE and tests of global functioning (IQ and academic achievement) tend to be minimal and are typically attenuated by environmental variables (e.g., caregiving environment). On the other hand, significant negative associations have been reported in tests of executive functioning (sustained attention, inhibitory control, and behavioral regulation), even with covariate control. These findings are consistent with animal models of PDE that report developmental abnormalities in brain regions associated with strong dopaminergic innervation including the striatum, anterior cingulate cortex, and prefrontal cortex. In humans, these regions are putatively involved in executive functions that coordinate the basic cognitive processes required for goal-directed action (e.g., attention inhibitory control, planning, working memory). The objective of the present study was to assess the effects of PDE on brain functioning during adolescence. Methods: fMRI was used to examine visuospatial working memory (VSWM) in 35 adolescents (mean: 14.3 years); 20 with intrauterine exposure to cocaine, heroin, or both and 15 unexposed children from the same community. All participants performed a 2-back VSWM paradigm that required dynamic storage and manipulation of spatial information. Whole-brain functional EPI scans were acquired using a 3T Siemens Scanner with standard parameters. Participants completed one 6-minute block-design run that alternated between a 30 second control condition (which required observation of visual stimuli, sustained attention, and a motor response) and 30 seconds of the VSWM condition. Brain responses were analyzed using the AFNI software package with appropriate contrasts and p < 0.05 corrected for multiple comparisons. Results: Across all participants, the VSWM task activated the frontal-parietal attention network including bilateral superior parietal lobules, precuneus, middle frontal gyri, superior frontal gyri, and insular cortex. Significant deactivations were observed in regions of the “default network,” including the left anterior cingulate gyrus, medial frontal gyrus, posterior cingulate, and bilateral parahippocampal cortices. Whole-brain between group comparisons with both age and gender entered as covariates revealed 3 regions that were differentially activated in the drug-exposed compared to the non-exposed group. These regions included right inferior parietal lobe, right precentral gryus, and left cuneus. The drug-exposed group showed deactivation of the right inferior parietal lobule compared to no change in the non-exposed group. The non-exposed group showed activations in both the right precentral gyrus and left cuneus compared to no change in the drug-exposed group. These differences in activations were detected despite equivalent behavioral performance on the task (i.e., accuracy and response time) and after statistically controlling environmental variables that differed between the groups, including placement in nonmaternal care, maternal age at time of birth and prenatal exposure to cigarettes. Discussion: Despite similar task performance, adolescents with a history of PDE showed different neural activations than the comparison group. Regions that were differentially activated are implicated in sequencing task information (i.e., right parietal lobe), working memory performance in healthy control children (i.e., right precentral gyrus), and visual attention (i.e., left cuneus). These results suggest regions and components of working memory processing that may be differentially affected by PDE in adolescence.This study was supported by the National Institute on Drug Abuse (NIDA) – Intramural Research Program and NIDA grants R01-DA07432 and R01-DA021059

Down-regulation of BDNF in cell and animal models increases striatal-enriched protein tyrosine phosphatase 61 (STEP61) levels

Brain-derived neurotrophic factor (BDNF) regulates synaptic strengthening and memory consolidation, and altered BDNF expression is implicated in a number of neuropsychiatric and neurodegenerative disorders. BDNF potentiates N-methyl-D-aspartate receptor function through activation of Fyn and ERK1/2. STriatal-Enriched protein tyrosine Phosphatase (STEP) is also implicated in many of the same disorders as BDNF but, in contrast to BDNF, STEP opposes the development of synaptic strengthening. STEP-mediated dephosphorylation of the NMDA receptor subunit GluN2B promotes internalization of GluN2B-containing NMDA receptors, while dephosphorylation of the kinases Fyn, Pyk2, and ERK1/2 leads to their inactivation. Thus, STEP and BDNF have opposing functions. In this study, we demonstrate that manipulation of BDNF expression has a reciprocal effect on STEP61 levels. Reduced BDNF signaling leads to elevation of STEP61 both in BDNF(+/-) mice and after acute BDNF knockdown in cortical cultures. Moreover, a newly identified STEP inhibitor reverses the biochemical and motor abnormalities in BDNF(+/-) mice. In contrast, increased BDNF signaling upon treatment with a tropomyosin receptor kinase B agonist results in degradation of STEP61 and a subsequent increase in the tyrosine phosphorylation of STEP substrates in cultured neurons and in mouse frontal cortex. These findings indicate that BDNF-tropomyosin receptor kinase B signaling leads to degradation of STEP61 , while decreased BDNF expression results in increased STEP61 activity. A better understanding of the opposing interaction between STEP and BDNF in normal cognitive functions and in neuropsychiatric disorders will hopefully lead to better therapeutic strategies. Altered expression of BDNF and STEP61 has been implicated in several neurological disorders. BDNF and STEP61 are known to regulate synaptic strengthening, but in opposite directions. Here, we report that reduced BDNF signaling leads to elevation of STEP61 both in BDNF(+/-) mice and after acute BDNF knockdown in cortical cultures. In contrast, activation of TrkB receptor results in the degradation of STEP61 and reverses hyperlocomotor activity in BDNF(+/-) mice. Moreover, inhibition of STEP61 by TC-2153 is sufficient to enhance the Tyr phosphorylation of STEP substrates and also reverses hyperlocomotion in BDNF(+/-) mice. These findings give us a better understanding of the regulation of STEP61 by BDNF in normal cognitive functions and in neuropsychiatric disorders

BDNF Induces Striatal-Enriched Protein Tyrosine Phosphatase 61 Degradation Through the Proteasome

Brain-derived neurotrophic factor (BDNF) promotes synaptic strengthening through the regulation of kinase and phosphatase activity. Conversely, striatal-enriched protein tyrosine phosphatase (STEP) opposes synaptic strengthening through inactivation or internalization of signaling molecules. Here, we investigated whether BDNF regulates STEP levels/activity. BDNF induced a reduction of STEP61 levels in primary cortical neurons, an effect that was prevented by inhibition of tyrosine kinases, phospholipase C gamma, or the ubiquitin-proteasome system (UPS). The levels of pGluN2B(Tyr1472) and pERK1/2(Thr202/Tyr204), two STEP substrates, increased in BDNF-treated cultures, and blockade of the UPS prevented STEP61 degradation and reduced BDNF-induced GluN2B and ERK1/2 phosphorylation. Moreover, brief or sustained cell depolarization reduced STEP61 levels in cortical neurons by different mechanisms. BDNF also promoted UPS-mediated STEP61 degradation in cultured striatal and hippocampal neurons. In contrast, nerve growth factor and neurotrophin-3 had no effect on STEP61 levels. Our results thus indicate that STEP61 degradation is an important event in BDNF-mediated effects

QUALITY OF WORK-LIFE ON EMPLOYEE RETENTION AND JOB SATISFACTION: THE MODERATING ROLE OF JOB PERFORMANCE

Purpose: A work-life balance leads employees’ texture towards job satisfaction for they can well-work whereas in the institutions; consequently they do not require to be hampered by outside problems. In the recent competitive world, among the companies, it is aggregate along with the global economic growth. This study intended to discover the impact of quality of work-life on employee retention and job satisfaction with the moderation of job performance. Methods: This study has 383 as a sample by using a simple random sample technique. A structured measurement scale was used. The researcher framed the conceptual framework with the support of literature. Basic analysis was tested and multiple linear regression was used to validate the constructed hypotheses. Findings: The result found that there is an impact of quality of work-life on employee retention and job satisfaction among the faculty members in higher education institutions. Job performance plays a moderation role in the relationship among the variables. Quality of the work-life and employee retention leads to better satisfaction among the employees

OCR Prediction Using Support Vector Machine Based on Piezocone Data

The determination of the overconsolidation ratio (OCR) of clay deposits is an important task in geotechnical engineering practice. This paper examines the potential of a support vector machine (SVM) for predicting the OCR of clays from piezocone penetration test data. SVM is a statistical learning theory based on a structural risk minimization principle that minimizes both error and weight terms. The five input variables used for the SVM model for prediction of OCR are the corrected cone resistance (qt), vertical total stress (sigmav), hydrostatic pore pressure (u0), pore pressure at the cone tip (u1), and the pore pressure just above the cone base (u2). Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. From the sensitivity analysis, it is clear that qt=primary in situ data influenced by OCR followed by sigmav, u0, u2, and u1. Comparison between SVM and some of the traditional interpretation methods is also presented. The results of this study have shown that the SVM approach has the potential to be a practical tool for determination of OCR

Early squamous neoplasia of the esophagus: The endoscopic approach to diagnosis and management

Considerable focus has been placed on esophageal adenocarcinoma in the last 10 years because of its rising incidence in the West. However, squamous cell cancer (SCC) continues to be the most common type of esophageal cancer in the rest of the world. The detection of esophageal SCC (ESCC) in its early stages can lead to early endoscopic resection and cure. The increased incidence of ESCC in high-risk groups, such as patients with head and neck squamous cancers, highlights the need for screening programs. Lugol's iodine chromoendoscopy remains the gold standard technique in detecting early ESCC, however, safer techniques such as electronic enhancement or virtual chromoendoscopy would be ideal. In addition to early detection, these new “push-button” technological advancements can help characterize early ESCC, thereby further aiding the diagnostic accuracy and facilitating resection. Endoscopic resection (ER) of early ESCC with negligible risk of lymph node metastases has been widely accepted as an effective therapeutic strategy because it offers similar success rates when compared to esophagectomy, but carries lesser morbidity and mortality. Endoscopic submucosal dissection (ESD) is the preferred technique of ER in lesions larger than 15 mm because it provides higher rates of en bloc resections and lower local recurrence rates when compared to endoscopic mucosal resection (EMR)