2,713 research outputs found

    Al Qaeda at the bar: coordinating ideologues and mercenaries in terrorist organizations

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    Most terrorist groups have limited lifespans. A number of scholars and casual observers have noted that terrorist organizations often are comprised of two types of participants: ideologues or "true believers" dedicated to the group's cause, and mercenaries, who are adept at raising money through illegal means. The latter are interested primarily in their personal gains and have relatively little ideological commitment. Terrorist groups need both participants in order to function effectively. The purpose of the study is to understand the impact of communication on the compositions of terrorist groups. Three experimental treatments consider a coordination problem, and focus on the behavior of the mercenaries. Participants choose whether or not to participate in a terrorist attack. Payoffs are U-shaped in the number of participants, and increase with the number of successful attacks. The treatments allow communication between a leader and frontline fighters ("leader" treatment) or among the frontline fighters themselves ("communication" treatment). In the first treatment, a group leader can post messages to the members, which has a 19 % coordination success rate. For the communication treatment, all participants can post messages anonymously to each other, which yields a 27 % coordination success rate. By contrast, the baseline ("no communication" treatment) shows a success rate of 11 %. We conclude from our experimental evidence that disrupting communications among the frontline fighters is more effective in terminating terrorist organizations

    Brain Metastases in Soft Tissue Sarcomas: Case Report and Literature Review

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    Background and purpose: Brain metastasis is a relatively uncommon event in the natural history of soft tissue sarcomas. The increasing use of chemotherapy may have caused a reduction in local relapses as well as distant failures leading to an improvement in survival, thereby allowing metachronous seeding of the brain, a sanctuary site. The purpose of this report is to increase awareness amongst clinicians regarding such a possibility

    Efficient assembly of very short oligonucleotides using T4 DNA Ligase

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    <p>Abstract</p> <p>Background</p> <p>In principle, a pre-constructed library of all possible short oligonucleotides could be used to construct many distinct gene sequences. In order to assess the feasibility of such an approach, we characterized T4 DNA Ligase activity on short oligonucleotide substrates and defined conditions suitable for assembly of a plurality of oligonucleotides.</p> <p>Findings</p> <p>Ligation by T4 DNA Ligase was found to be dependent on the formation of a double stranded DNA duplex of at least five base pairs surrounding the site of ligation. However, ligations could be performed effectively with overhangs smaller than five base pairs and oligonucleotides as small as octamers, in the presence of a second, complementary oligonucleotide. We demonstrate the feasibility of simultaneous oligonucleotide phosphorylation and ligation and, as a proof of principle for DNA synthesis through the assembly of short oligonucleotides, we performed a hierarchical ligation procedure whereby octamers were combined to construct a target 128-bp segment of the beta-actin gene.</p> <p>Conclusions</p> <p>Oligonucleotides as short as 8 nucleotides can be efficiently assembled using T4 DNA Ligase. Thus, the construction of synthetic genes, without the need for custom oligonucleotide synthesis, appears feasible.</p

    Inhibition of N-linked glycosylation impairs ALK phosphorylation and disrupts pro-survival signaling in neuroblastoma cell lines

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    <p>Abstract</p> <p>Background</p> <p>The Anaplastic Lymphoma Kinase (ALK) is an orphan receptor tyrosine kinase, which undergoes post-translational N-linked glycosylation. The catalytic domain of ALK was originally identified in the t(2;5) translocation that produces the unglycosylated oncogenic protein NPM-ALK, which occurs in Anaplastic Large Cell Lymphoma (ALCL). Recently, both germline and somatic activating missense mutations of ALK have been identified in neuroblastoma (NB), a pediatric cancer arising from neural crest cells. Moreover, we previously reported that ALK expression is significantly upregulated in advanced/metastatic NB. We hypothesized that ALK function may depend on N-linked glycosylation and that disruption of this post-translational modification would impair ALK activation, regardless the presence of either gene mutations or overexpression.</p> <p>Methods</p> <p>We employed tunicamycin to inhibit N-linked glycosylation. The following ALK-positive NB cell lines were used: SH-SY5Y and KELLY (ALK mutation F1174L), UKF-NB3 (ALK mutation R1275Q) and NB1 (ALK amplification). As a control, we used the NB cell lines LA1-5S and NB5 (no ALK expression), and the ALCL cell line SU-DHL1 (NPM-ALK).</p> <p>Results</p> <p>Tunicamycin treatment of ALK-positive NB cells resulted in a hypoglycosylated ALK band and in decreased amounts of mature full size receptor. Concomitantly, we observed a marked reduction of mature ALK phosphorylation. On the contrary, tunicamycin had no effects on NPM-ALK phosphorylation in SU-DHL1 cells. Moreover, phosphorylation levels of ALK downstream effectors (AKT, ERK1/2, STAT3) were clearly impaired only in ALK mutated/amplified NB cell lines, whereas no significant reduction was observed in both ALK-negative and NPM-ALK-positive cell lines. Furthermore, inhibition of N-linked glycosylation considerably impaired cell viability only of ALK mutated/amplified NB cells. Finally, the cleavage of the Poly-ADP-ribose-polymerase (PARP) suggested that apoptotic pathways may be involved in cell death.</p> <p>Conclusions</p> <p>In this study we showed that inhibition of N-linked glycosylation affects ALK phosphorylation and disrupts downstream pro-survival signaling, indicating that inhibition of this post-translational modification may be a promising therapeutic approach. However, as tunicamycin is not a likely candidate for clinical use other approaches to alter N-linked glycosylation need to be explored. Future studies will assess whether the efficacy in inhibiting ALK activity might be enhanced by the combination of ALK specific small molecule and N-linked glycosylation inhibitors.</p

    Rib head protrusion into the central canal in type 1 neurofibromatosis

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    Intraspinal rib head dislocation is an important but under-recognized consequence of dystrophic scoliosis in patients with neurofibromatosis 1 (NF1). To present clinical and imaging findings of intraspinal rib head dislocation in NF1. We retrospectively reviewed clinical presentation, imaging, operative reports and post-operative courses in four NF1 patients with intraspinal rib head dislocation and dystrophic scoliosis. We also reviewed 17 cases from the English literature. In each of our four cases of intraspinal rib head dislocation, a single rib head was dislocated on the convex apex of the curve, most often in the mid- to lower thoracic region. Cord compression occurred in half of these patients. Analysis of the literature yielded similar findings. Only three cases in the literature demonstrates the MRI appearance of this entity; most employ CT. All of our cases include both MRI and CT; we review the subtle findings on MRI. Although intraspinal rib head dislocation is readily apparent on CT, sometimes MRI is the only cross-sectional imaging performed. It is essential that radiologists become familiar with this entity, as subtle findings have significant implications for surgical management

    A Method for Serial Tissue Processing and Parallel Analysis of Aberrant Crypt Morphology, Mucin Depletion, and Beta-Catenin Staining in an Experimental Model of Colon Carcinogenesis

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    The use of architectural and morphological characteristics of cells for establishing prognostic indicators by which individual pathologies are assigned grade and stage is a well-accepted practice. Advances in automated micro- and macroscopic image acquisition and digital image analysis have created new opportunities in the field of prognostic assessment; but, one area in experimental pathology, animal models for colon cancer, has not taken advantage of these opportunities. This situation is primarily due to the methods available to evaluate the colon of the rodent for the presence of premalignant and malignant pathologies. We report a new method for the excision and processing of the entire colon of the rat and illustrate how this procedure permitted the quantitative assessment of aberrant crypt foci (ACF), a premalignant colon pathology, for characteristics consistent with progression to malignancy. ACF were detected by methylene blue staining and subjected to quantitative morphometric analysis. Colons were then restained with high iron diamine–alcian blue for assessment of mucin depletion using an image overlay to associate morphometric data with mucin depletion. The subsequent evaluation of ACF for beta-catenin staining is also demonstrated. The methods described are particularly relevant to the screening of compounds for cancer chemopreventive activity

    Yes, research can inform health policy; but can we bridge the 'Do-Knowing It's Been Done' gap?

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    Copyright @ 2011 Hanney and Gonzalez.Provisional Abstract: This editorial introduces a new Supplement in Health Research Policy and Systems and highlighs the importance of assessing the impact of health research by examining whether we can move from 'Know-Do' to 'Do-Knowing It's Been Done'This article is made available through the Brunel Open Access publishing fund

    Co-Administration of IL-1+IL-6+TNF-α with Mycobacterium tuberculosis Infected Macrophages Vaccine Induces Better Protective T Cell Memory than BCG

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    BCG has been administered globally for more than 75 years, yet tuberculosis (TB) continues to kill more than 2 million people annually. Further, BCG protects childhood TB but is quite inefficient in adults. This indicates that BCG fails to induce long-term protection. Hence there is a need to explore alternative vaccination strategies that can stimulate enduring T cell memory response. Dendritic cell based vaccination has attained extensive popularity following their success in various malignancies. In our previous study, we have established a novel and unique vaccination strategy against Mycobacterium tuberculosis (M. tb) and Salmonella typhimurium by utilizing infected macrophages (IM). In short-term experiments (30 days), substantial degree of protection was observed. However, remarkable difference was not observed in long-term studies (240 days) due to failure of the vaccine to generate long-lasting memory T cells. Hence, in the present study we employed T cell memory augmenting cytokines IL-1+IL-6+TNF-α and IL-7+IL-15 for the induction of the enhancement of long-term protection by the vaccine. We co-administered the M. tb infected macrophages vaccine with IL-1+IL-6+TNF-α (IM-1.6.α) and IL-7+IL-15 (IM-7.15). The mice were then rested for a reasonably large period (240 days) to study the bona fide T cell memory response before exposing them to aerosolized M. tb. IM-1.6.α but not IM-7.15 significantly improved memory T cell response against M. tb, as evidenced by recall responses of memory T cells, expansion of both central as well as effector memory CD4 and CD8 T cell pools, elicitation of mainly Th1 memory response, reduction in the mycobacterial load and alleviated lung pathology. Importantly, the protection induced by IM-1.6.α was significantly better than BCG. Thus, this study demonstrates that not only antigen-pulsed DCs can be successfully employed as vaccines against cancer and infectious diseases but also macrophages infected with M. tb can be utilized with great efficacy especially in protection against TB

    Liquid-gas phase transition in nuclear multifragmentation

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    The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been a very important focal point of experimental endeavours in heavy ion collisions, in the last fifteen years. Simultaneously theoretical models have been developed to provide information about the equation of state and reaction mechanisms consistent with the experimental observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos corrected, minor text change
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