Suppression of steady-state, but not stimulus-induced NF-kappaB activity inhibits alphavirus-induced apoptosis.

Recent studies have established cell type- specific, proapoptotic, or antiapoptotic functions for the transcription factor NF-kappaB. In each of these studies, inhibitors of NF-kappaB activity have been present before the apoptotic stimulus, and so the role of stimulus- induced NF-kappaB activation in enhancing or inhibiting survival could not be directly assessed. Sindbis virus, an alphavirus, induces NF-kappaB activation and apoptosis in cultured cell lines. To address whether Sindbis virus- induced NF-kappaB activation is required for apoptosis, we used a chimeric Sindbis virus that expresses a superrepressor of NF-kappaB activity. Complete suppression of virus-induced NF-kappaB activity neither prevents nor potentiates Sindbis virus-induced apoptosis. In contrast, inhibition of NF-kappaB activity before infection inhibits Sindbis virus-induced apoptosis. Our results demonstrate that suppression of steady-state, but not stimulus-induced NF-kappaB activity, regulates expression of gene products required for Sindbis virus-induced death. Furthermore, we show that in the same cell line, NF-kappaB can be proapoptotic or antiapoptotic depending on the death stimulus. We propose that the role of NF-kappaB in regulating apoptosis is determined by the death stimulus and by the timing of modulating NF-kappaB activity relative to the death stimulus

Building a Stronger CASA: Extending the Computers Are Social Actors Paradigm

The computers are social actors framework (CASA), derived from the media equation, explains how people communicate with media and machines demonstrating social potential. Many studies have challenged CASA, yet it has not been revised. We argue that CASA needs to be expanded because people have changed, technologies have changed, and the way people interact with technologies has changed. We discuss the implications of these changes and propose an extension of CASA. Whereas CASA suggests humans mindlessly apply human-human social scripts to interactions with media agents, we argue that humans may develop and apply human-media social scripts to these interactions. Our extension explains previous dissonant findings and expands scholarship regarding human-machine communication, human-computer interaction, human-robot interaction, human-agent interaction, artificial intelligence, and computer-mediated communication

The Frontiers of Microcredit Programs in Bangladesh: An Empirical Review

Panel survey data indicated that about 47 percent of total land-poor (defined as household owning less than half an acre of land) rural households were non-participants in microcredit programs in Bangladesh. This exploratory study was conducted to have an appraisal of microfinance institutions’ (MFIs) peer-monitoring model or group-based activities in Bangladesh that would help to identify key access barriers to micro-entrepreneurship and microcredit initiatives. The sample was taken on a random basis from Gazipur, Savar and Narayanganj around Dhaka city. The respondents (non-members of MFIs) were asked to evaluate their judgments on different objects selected in the questionnaire. Respondents ranked the attributes on a number of itemized five-point scale ratings bounded at each end by one of two bipolar adjectives. The result of this study indicated that two types of forces are active in this dissociation of the rural ultra-poor with MFIs. One is self-exclusion and the other is indirect-push-exclusion by the MFIs. Besides, there have been some identified factors in principal component factor analysis that are heavily weighted by the respondents as the key access barriers such as tight repayment methods of loan, high costs of credit, disciplinary imperatives, loan use opportunity, risk of loan and religious restrictions. The regression analysis shows that loan repayment method, loan utilization opportunities and religious restrictions are significant variables that play major role in the nonparticipation of the rural poor in microcredit programs in rural Bangladesh. Hence, similar to many others, the findings of this study conclude that microcredit is not the only way out for all the rural poor to resolve poverty

Paraplegia induced by mild trauma in a child with thoracic spinal arachnoid cyst

AbstractSpinal arachnoid cysts are rare entities that often present with progressive myelopathy and are treated via surgical excision and fenestration. The acute onset of symptoms from these lesions is not well described in the literature. We report an 18-month-old child with acute onset of paraplegia following a mild trauma, who was found to have a compressive dorsal thoracic intradural spinal arachnoid cyst and emergently treated via surgical decompression and cyst resection. After several months of physical therapy the child achieved meaningful neurologic recovery. Spinal arachnoid cysts can cause acute decompensation in children with serious neurological injury following mild trauma, this risk should be weighed when managing asymptomatic lesions

Study on viscosity induced contrast in ultrasound color flow imaging of carotid atherosclerosis

Efficient imaging of blood flow disturbances resulted from carotid atherosclerosis plays a vital role clinically to predict brain stroke risk. Carotid atherosclerosis and its development is closely linked with raised blood viscosity. Therefore, study of viscosity changing hemodynamic effect has importance and it might be useful for improved examination of carotid atherosclerosis incorporating the viscosity induced contrast in conventional ultrasound imaging. This work considered the design of realistic models of atherosclerotic carotid artery of different stages and solved to compute the hemodisturbances using computational fluid dynamics (CFD) by finite element method (FEM) to investigate viscosity changes effect. Ultrasound color flow image of velocities of blood have been constructed using phase shift information estimated with autocorrelation of Hilbert transformed simulated backscattered radiofrequency (RF) signals from moving blood particles. The simulated ultrasound images have been compared with CFD simulation images and identified a good match between them. The atherosclerosis stages of the models have been investigated from the estimated velocity data. It has been observed that the blood velocities increase noticeably in carotid atherosclerotic growths and velocity distribution changes with viscosity variations. It is also found importantly that the viscosity induced contrast associated to atherosclerosis is detectable in ultrasound color flow imaging. The findings of this work might be useful for better investigation of carotid atherosclerosis as well as prediction of its progression to reduce the stroke risk

Dissociative Autoionization in (1+2)-photon Above Threshold Excitation of H2 Molecules

We have theoretically studied the effect of dissociative autoionization on the photoelectron energy spectrum in (1+2)-photon above threshold ionization(ATI) of H2 molecules. We have considered excitation from the ground state X-singlet-Sigma-g+(v=0,j) to the doubly excited autoionizing states of singlet-Sigma-u+ and singlet-Pi-u+ symmetry, via the intermediate resonant B-singlet-Sigma-u+(v=5,j) states. We have shown that the photoelectron energy spectrum is oscillatory in nature and shows three distinct peaks above the photoelectron energy 0.7 eV. This feature has been observed in a recent experiment by Rottke et al, J. Phys. B, Vol. 30, p-4049 (1997).Comment: 11 pages and 4 figure

Compression of X-ray Free Electron Laser pulses to attosecond duration

State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration. Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency. Pulses of this type may pave the way for routine time resolution of electrons in nm size potentials. Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration