Separate metabolic pathways leading to DNA fragmentation and apoptotic nuclear chromatin condensation

Apoptosis is the predominant form of cell death observed in a variety of physiological and pathological conditions such as cancer involution, insect metamorphosis, the development of the immune and nervous systems, and embryogenesis. The typical nuclear changes taking place in apoptotic cells include extensive condensation of chromatin and internucleosomal DNA fragmentation into units of 200 base pairs. However, the mechanisms responsible for both chromatin condensation and DNA fragmentation have yet to be elucidated. In this study, micrococcal nuclease and the divalent cations, Ca2+ and Mg2+, were applied to isolated nuclei in an attempt to reconstitute in vitro the digestion of genomic DNA associated with apoptosis. Micrococcal nuclease was found to induce a typical pattern of DNA fragmentation, but did not give rise to chromatin condensation, whereas Ca2+/Mg2+ induced both chromatin condensation and DNA fragmentation in isolated mouse liver nuclei. When the endonuclease inhibitor ZnCl2 was used, the DNA fragmentation induced by Ca2+/Mg2+ in nuclei could be completely inhibited, but chromatin condensation still occurred. For comparison, intact liver cells were treated with valinomycin, a potassium ionophore, which gave rise to an atypical cell death, with chromatin condensation appearing without DNA fragmentation. Our results suggest that endonuclease activation in apoptosis is neither necessary nor sufficient to induce chromatin condensation, and that DNA fragmentation and chromatin condensation may be triggered through separate pathways during apoptosis

Microstructures, Mechanical Properties and Transformation Behavior in Ni49.6Ti35.4Hf15 Alloy Produced with High-Pressure Torsion

High-pressure torsion (HPT) was applied for the Ni49.6Ti35.4Hf15 (at.%) alloy up to 1/4, 2 and 16 turns under a pressure of 4.0 GPa. The samples were examined using X-ray diffraction (XRD), transmission electron microscope (TEM) and microhardness measurements. The results indicate that the mixture of an amorphous and nanocrystalline microstructure developed in the investigated NiTiHf alloy as the number of HPT turns was increased to two. The average hardness of the samples increased from 330 Hv to 500 Hv after 16 turns of HPT. Very fine martensite developed when the HPT-processed samples were annealed at 550 ⁰C and the finer microstructures were attained with higher HPT turns. Differential scanning calorimetry (DSC) tests were performed in the post-HPT annealing samples to clarify the transformation behavior after severe plastic deformation in HPT and subsequent annealing, so as to provide an experimental basis for the application of the shape memory alloy. The transformation temperature of the alloy decreased remarkably when the number of turns of HPT reached 16. It is suggested that the deformation extent and annealing temperatures should be considered in order to maintain a high transformation temperature while utilizing the strengthening effect of HPT in the NiTiHf alloy

Differential Gene Expression in Primary Cultured Sensory and Motor Nerve Fibroblasts

Fibroblasts (Fbs) effectively promote Schwann cells (SCs) migration, proliferation, and neurite regeneration. Whether Fbs express different motor and sensory phenotypes that regulate the cell behavior and peripheral nerve function has not been elucidated. The present study utilized the whole rat genome microarray analysis and identified a total of 121 differentially expressed genes between the primary cultured motor and sensory Fbs. The genes with high expression in sensory Fbs were related to proliferation, migration, chemotaxis, motility activation, protein maturation, defense response, immune system, taxis, and regionalization, while those with high expression in motor Fbs were related to neuron differentiation, segmentation, and pattern specification. Thus, the significant difference in the expression of some key genes was found to be associated with cell migration and proliferation, which was further validated by quantitative real-time PCR (qPCR). The cell proliferation or migration analysis revealed a higher rate of cell migration and proliferation of sensory Fbs than motor Fbs. Moreover, the downregulated expression of chemokine (C-X-C motif) ligand 10 (CXCL10) and chemokine (C-X-C motif) ligand 3 (CXCL3) suppressed the proliferation rate of sensory Fbs, while it enhanced that of the motor Fbs. However, the migration rate of both Fbs was suppressed by the downregulated expression of CXCL10 or CXCL3. Furthermore, a higher proportion of motor or sensory SCs migrated toward their respective (motor or sensory) Fbs; however, few motor or sensory SCs co-cultured with the other type of Fbs (sensory or motor, respectively), migrated toward the Fbs. The current findings indicated that Fbs expressed the distinct motor and sensory phenotypes involved in different patterns of gene expression, biological processes, and effects on SCs. Thus, this study would provide insights into the biological differences between motor and sensory Fbs, including the role in peripheral nerve regeneration

Herding in the consumption and purchase of digital goods and moderators of the herding bias

Digital goods are increasingly produced by average individuals in a serialized fashion. However, it is unclear whether users engage in herding in the consumption and purchase of such digital goods and what the moderators of the herding effect are. Thus, we propose a simultaneous equations model based on herding theory to theoretically examine users’ potential herding behavior through two competing effects: the private signal effect and the sequential actions effect, which refer to the impact of the private signals and observed sequential actions of others on user quality inference and herding, respectively. The model is implemented in a hierarchical Bayes framework, and it is estimated using data from the top Chinese literature site. The empirical results suggest that users engage in rational herding in both digital book consumption and purchase on the focal site and that the herding bias is surprisingly stronger for purchasing. Product features significantly mitigate the herding bias, while the reputation of the producer and competition exacerbate the herding effect. The impact of this rational herding is also quantified. This study offers new insights and important theoretical and managerial implications for marketing researchers, amateur producers, marketing managers, and publishers

Learning user real-time intent for optimal dynamic web page transformation

Many e-commerce websites struggle to turn visitors into real buyers. Understanding online users\u27 real-time intent and dynamic shopping cart choices may have important implications in this realm. This study presents an individual-level, dynamic model with concurrent optimal page adaptation that learns users\u27 real-time, unobserved intent from their online cart choices, then immediately performs optimal Web page adaptation to enhance the conversion of users into buyers. To suggest optimal strategies for concurrent page adaptation, the model analyzes each individual user\u27s browsing behavior, tests the effectiveness of different marketing and Web stimuli, as well as comparison shopping activities at other sites, and performs optimal Web page transformation. Data from an online retailer and a laboratory experiment reveal that concurrent learning of the user\u27s unobserved purchase intent and real-time, intent-based optimal interventions greatly reduce shopping cart abandonment and increase purchase conversions. If the concurrent, intent-based optimal page transformation for the focal site starts after the first page view, shopping cart abandonment declines by 32.4% and purchase conversion improves by 6.9%. The optimal timing for the site to intervene is after three page views, to achieve efficient learning of users\u27 intent and early intervention simultaneously

Perforin binding to cells and lipid membranes determined by a simple competition assay

Perforin-mediated lysis consists of at least three steps: perforin binding to the target cell, insertion into the plasma membrane, and polymerization to form pores. Perforin binding, the first step, is critical for pore formation. Accordingly, a competition assay was here established for detecting the perforin-binding activities of nucleated cells and lipid membrane vesicles such as cytoplasts or liposomes. The competition assay has certain advantages over the 51Cr release assay, since no isotope and less perforin are needed for the competition assay, and the perforin-binding activity of liposomes and proteolytic enzyme-treated and fixed nucleated cells can also be detected. The competition assay was used to study the mechanism of resistance of cytolytic T lymphocytes (CTL) to perforin-mediated lysis. The results from this assay indicate that perforin-binding activity is not a function of membrane rigidity, and that there is a direct correlation between the ability of cells to bind perforin and their susceptibility to lysis by perforin, i.e., resistant CTL and their corresponding cytoplasts bind perforin much less effectively than susceptible tumor cells and their cytoplasts. A model is proposed whereby a surface molecule or complex of molecules on CTL interferes with perforin-binding activity, thus protecting CTL from perforin-mediated lysis

"Endemol Turkey launches drama unit" - C21 Media

"Endemol Turkey has set up a drama unit and has appointed an executive from one of the country’s biggest free-to-air broadcasters to head it. Hulya Vural, who was head of drama at ATV and previously held the same post at Turkey’s Star network, started in the newly created head of drama role at Endemol Turkey in January. The company now aims to launch a drama project in the next 12 months, as it aims to cash in on the country’s booming scripted market, Endemol Turkey MD Ansi Elagoz told C21. “..

A novel strategy for fabricating phase transforming NiTi shape memory alloy via multiple processes of severe plastic deformation

NiTi shape memory alloy was successfully fabricated from Ni/Ti multilayers via aninnovatively combinative route consisting of accumulative roll bonding (ARB), highpressure torsion (HPT) and annealing. Due to the severe plastic deformation induced by ARB and HPT, the subsequently post annealing time was significantly reduced. Differential scanning calorimetry (DSC) analysis confirms the occurrence ofaustenitic and martensitic transformations during heating and cooling process,implying that the shape memory effect was obtained

Purification of a membrane-associated serine esterase from murine cytotoxic T lymphocytes by a single reverse phase column

The plasma and organelle membranes of a cytotoxic T lymphocyte line, CTLL-R8, were isolated by subcellular fractionation. After dissolving in detergent-containing buffer, the membrane proteins were isolated by high-performance liquid chromatography on a single reverse-phase column. The serine esterase activity in the fractions was detected by measuring hydrolysis of the ester compound Nα-benzyloxycarbonyl-l-lysine thiobenzyl ester. A major band was revealed in the fraction with highest serine esterase activity. Under sodium dodecyl sulfate-polyacrylamide gel electrophoresis, this band assumes a molecular weight of about 30 kDa. The amino-terminal sequence of the protein was analyzed and shows 100% identity with that of MCSP-3/granzyme F, a soluble serine esterase previously identified in the cytoplasmic granules of cytotoxic T lymphocytes. Modifications of this reverse-phase column method would thus represent a simple, convenient strategy for obtaining high yields of all the lymphocyte surface proteases, which could then be further characterized for function