Stress–strain curve for concrete in circular columns based on elastoplastic analysis

This paper presents a stress–strain curve that describes the axial behavior of concrete in circular columns with lateral reinforcement. As opposed to most studies on this subject, which used semiempirical methods, the proposed stress–strain relations are based on a theoretical derivation. They have been derived from analysis of the problem’s full range according to the theories of elasticity and plasticity. Based on these theories, the current study analytically examines the influence of the main variables, such as the volumetric lateral reinforcement ratio and the material properties, on the behavior of circular confined concrete columns and proposes theoretical expressions that describe their stress–strain relations. Application of the proposed curve shows good agreement with published test results. Since these expressions were derived from a theoretical analysis, they can be considered as an analytical verification of existing empirical curves, yet they are also simple enough for practical applications.     

The feasibility of boron removal from water by capacitive deionization

We report on the possibility of removing boron (in the form of boric acid) from water by electrochemical means. We explore capacitive de-ionization (CDI) processes in which local changes in pH near the surface of high-surface-area activated carbon fiber (ACF) electrodes during charging are utilized, in order to dissociate boric acid into borate ions which can be electro-adsorbed onto the positive electrode in the CDI cells. For this purpose, a special flow-through CDI cell was constructed in which the feed solution flows through the electrodes. Local pH changes near the carbon electrode surface were investigated using a MgCl₂ solution probe in three- (with reference) and two-electrode cells, and described qualitatively. We show that, to a certain extent, boron can indeed be removed from water by CDI.     

The assessment of four different correction models applied to the diffuse radiation measured with a shadow ring using global and normal beam radiation measurements for Beer Sheva, Israel

The measurement of the diffuse radiation incident on a horizontal surface, a priori a straightforward task, is fraught with difficulties. It is possible to measure the diffuse radiation by three different techniques: two of which measure it directly and the third indirectly. The most accurate is the indirect one, which is based upon the concurrent measurements of the horizontal global and the normal incidence beam radiation. The disadvantage of this being the relatively expensive tracking system required for measuring the latter. The diffuse radiation can be measured directly with a pyranometer outfitted with either an occulting disk or shadow ring, which prevent the beam radiation from impinging on the pyranometer sensor. The occulting disk can provide accurate measurements of the diffuse radiation but it requires a relatively expensive sun tracking system in the east–west axis. The shadow ring is a stationary device with regard to the east–west axis and blocks the beam radiation component by creating a permanent shadow on the pyranometer sensor. The major disadvantage of the shadow ring is that it also blocks that portion of the diffuse radiation obscured by the shadow ring. This introduces a measurement error that must be corrected to account for that portion of the sky obscured by the shadow band. In addition to this geometric correction factor there is a need to correct for anisotropic sky conditions. Four correction models have been applied to the data for Beer Sheva, Israel and the results have been evaluated both graphically and statistically. An attempt has been made to score the relative performance of the models under different sky conditions.     

Chemo-Enzymatic Fluorescence Labeling Of Genomic DNA For Simultaneous Detection Of Global 5-Methylcytosine And 5-Hydroxymethylcytosine**

5-Methylcytosine and 5-hydroxymethylcytosine are epigenetic modifications involved in gene regulation and cancer. We present a new, simple, and high-throughput platform for multi-color epigenetic analysis. The novelty of our approach is the ability to multiplex methylation and de-methylation signals in the same assay. We utilize an engineered methyltransferase enzyme that recognizes and labels all unmodified CpG sites with a fluorescent cofactor. In combination with the already established labeling of the de-methylation mark 5-hydroxymethylcytosine via enzymatic glycosylation, we obtained a robust platform for simultaneous epigenetic analysis of these marks. We assessed the global epigenetic levels in multiple samples of colorectal cancer and observed a 3.5-fold reduction in 5hmC levels but no change in DNA methylation levels between sick and healthy individuals. We also measured epigenetic modifications in chronic lymphocytic leukemia and observed a decrease in both modification levels (5-hydroxymethylcytosine: whole blood 30 %; peripheral blood mononuclear cells (PBMCs) 40 %. 5-methylcytosine: whole blood 53 %; PBMCs 48 %). Our findings propose using a simple blood test as a viable method for analysis, simplifying sample handling in diagnostics. Importantly, our results highlight the assay‘s potential for epigenetic evaluation of clinical samples, benefiting research and patient management.     

Verbal and visuospatial recall by younger and older subjects: Use of matched tasks.

In this study, 18 older (over age 65, M?=?75.61 years) and 18 younger (below age 40 and over age 17, M?=?26.44 years) healthy volunteers were tested on verbal and visuospatial recall. Tasks were matched on discriminating power. Older Ss performed worse than younger Ss on both tasks. The older Ss also showed a larger deficit in visuospatial than in verbal recall, relative to the younger Ss. These results are consistent with the theory of aging according to which verbal tasks are more resistant to deterioration than are nonverbal tasks. A psychological explanation based on lifetime experience with verbal material is preferred over the physiological explanation advocating faster aging of the right hemisphere. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of display methods for spatial point layout

. A series of six experiments compared several approaches to displaying 3D point information on a CRT screen. The methods used included perspective, motion, stereo, and numeric information, in various combinations. Measures included error rate and reaction times on three tasks, which all involved deciding whether a given configuration of dots exhibits a given property (collinearity, coplanarity, acute angle). Stereo proved to be the best method, being both faster and more accurate than the others. Simply presenting two perspective views is also effective, yet adding azimuthal motion under the subject's control is better on the most demanding task (coplanarity detection), while digital height information combined with a traditional top view (PPI) is slow, and especially inaccurate for coplanarity detection. Finally, the worst methods are the rotational interactive displays. Accuracy does not improve, whereas reaction times are considerably slower.     

Predicting behavior: Combining intention with investment.

In recent years, several social researchers have focused on ways to improve the prediction of behavior from attitudes. We examined the use of a measure of investment from the Rusbult and Farrell model of commitment as a means for enhancing prediction in the Ajzen and Fishbein intention model. Analysis of data collected from 95 subjects who were asked about their intention to participate in music-related activities over the next week and month showed that investment and its interaction with intention explain additional behavior variance beyond intention alone. The full model consisting of intention, investment, and their interaction explained, for the one-week period, nearly 53% of the criterion variance, and for the one-month period, nearly 78% of the criterion variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tyrosine phosphorylation of the novel protein-tyrosine kinase RAFTK during an early phase of platelet activation by an integrin glycoprotein IIb-IIIa-independent mechanism

A key regulatory event controlling platelet activation is mediated through the phosphorylation of several cellular proteins by protein-tyrosine kinases. The related adhesion focal tyrosine kinase (RAFTK) is a novel cytoplasmic tyrosine kinase and a member of the focal adhesion kinase (FAK) gene family. FAK phosphorylation in platelets is integrin-dependent, occurs in a late stage of platelet activation, and is dependent on platelet aggregation. In this study, we have investigated the involvement of RAFTK phosphorylation during different stages of platelet activation. Treatment of platelets with thrombin induced, in as early as 10 s, a rapid tyrosine phosphorylation of RAFTK in a time- and concentration-dependent manner. Treatment of platelets with thrombin in the absence of stirring or pretreatment of platelets with RGDS peptide prevented platelet aggregation, but not RAFTK phosphorylation. Furthermore, phosphorylation of RAFTK did not require integrin engagement since platelets treated with the 7E3 inhibitory antibodies that block fibrinogen binding to glycoprotein IIb-IIIa did not inhibit RAFTK phosphorylation. Similarly, platelets treated with LIBS6 antibodies, which specifically activate glycoprotein IIb-IIIa, did not induce RAFTK phosphorylation. Stimulation of platelets by several agonists such as collagen, ADP, epinephrine, and calcium ionophore A23187 induced RAFTK phosphorylation. Tyrosine phosphorylation of RAFTK in platelets is regulated by calcium and is mediated through the protein kinase C pathway. Phosphorylation of RAFTK is dependent upon the formation of actin cytoskeleton as disruption of actin polymerization by cytochalasin D significantly inhibited this phosphorylation. The RAFTK protein appears to be proteolytically cleaved by calpain in an aggregation dependent manner upon thrombin stimulation. These results demonstrate that RAFTK is tyrosine-phosphorylated during an early phase of platelet activation by an integrin- independent mechanism and is not dependent on platelet aggregation, suggesting different mechanisms of regulation for FAK and RAFTK phosphorylation during platelet activation.     

Asymptotic behaviour of infinite chains of coupled kinematic points: second-order equations

The behaviour of infinite chains of coupled kinematic points is studied. The points are second order, that is, they have mass. The chains could have been designed in any number of ways, including linear-quadratic optimal control. Behaviour means what happens as time goes to infinity. It is not assumed that the initial state is in the Hilbert space \(l^{2}\) because it has been seen in our previous work that in some situations this assumption has anomalous results. Instead, the initial state taken to be \(l^{\infty }\) . The finite-dimensional version of the infinite second-order system we study arises in physics in the theory of phonons.