388 research outputs found

    Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome <em>c</em>

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    Apoptosis, or programmed cell death, is a conserved and highly regulated pathway by which cells die1. Apoptosis can be triggered when cells encounter a wide range of cytotoxic stresses. These insults initiate signaling cascades that ultimately cause the release of cytochrome c from the mitochondrial intermembrane space to the cytoplasm2. The release of cytochrome c from mitochondria is a key event that triggers the rapid activation of caspases, the key cellular proteases which ultimately execute cell death3-4

    Eliciting a predatory response in the eastern corn snake (Pantherophis guttatus) using live and inanimate sensory stimuli: implications for managing invasive populations

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    North America's Eastern corn snake (Pantherophis guttatus) has been introduced to several islands throughout the Caribbean and Australasia where it poses a significant threat to native wildlife. Invasive snake control programs often involve trapping with live bait, a practice that, as well as being costly and labour intensive, raises welfare and ethical concerns. This study assessed corn snake response to live and inanimate sensory stimuli in an attempt to inform possible future trapping of the species and the development of alternative trap lures. We exposed nine individuals to sensory cues in the form of odour, visual, vibration and combined stimuli and measured the response (rate of tongue-flick [RTF]). RTF was significantly higher in odour and combined cues treatments, and there was no significant difference in RTF between live and inanimate cues during odour treatments. Our findings suggest chemical cues are of primary importance in initiating predation and that an inanimate odour stimulus, absent of simultaneous visual and vibratory cues, is a potential low-cost alternative trap lure for the control of invasive corn snake populations

    Giant pulses of pulsar radio emission

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    Review report of giant pulses of pulsar radio emission, based on our detections of four new pulsars with giant pulses, and the comparative analysis of the previously known pulsars with giant pulses, including the Crab pulsar and millisecond pulsar PSR B1937+21.Comment: Proceedings of the 363. WE-Heraeus Seminar on: Neutron Stars and Pulsars (Posters and contributed talks) Physikzentrum Bad Honnef, Germany, May.14-19, 2006, eds. W.Becker, H.H.Huang, MPE Report 291, pp.72-7

    ASC deficiency suppresses proliferation and prevents medulloblastoma incidence

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    Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is silenced by promoter methylation in many types of tumors, yet ASC’s role in most cancers remains unknown. Here, we show that ASC is highly expressed in a model of medulloblastoma, the most common malignant pediatric brain cancer; ASC is also expressed in human medulloblastomas. Importantly, while ASC deficiency did not affect normal cerebellar development, ASC knock-out mice on the Smoothened (ND2:SmoA1) transgenic model of medulloblastoma exhibited a profound reduction in medulloblastoma incidence and a delayed tumor onset. A similar decrease in tumorigenesis with ASC deficiency was also seen in the hGFAP-Cre:SmoM2 mouse model of medulloblastoma. Interestingly, hyperproliferation of the external granule layer (EGL) was comparable at P20 in both the wildtype and ASC-deficient SmoA1 mice. However, while the apoptosis and differentiation markers remained unchanged at this age, proliferation makers were decreased, and the EGL was reduced in thickness and area by P60. This reduction in proliferation with ASC deficiency was also seen in isolated SmoA1 cerebellar granule precursor cells in vitro, indicating that the effect of ASC deletion on proliferation was cell autonomous. Interestingly, ASC deficient SmoA1 cerebella exhibited disrupted expression of genes in the TGF-β pathway and increased level of nuclear Smad3. Together, these results demonstrate an unexpected role for ASC in Sonic hedgehog-driven medulloblastoma tumorigenesis, thus identifying ASC as a promising novel target for anti-tumor therapy

    Ripples in a pond: Do social work students need to learn about terrorism?

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    In the face of heightened awareness of terrorism, however it is defined, the challenges for social work are legion. Social work roles may include working with the military to ensure the well-being of service-men and women and their families when bereaved or injured, as well as being prepared to support the public within the emergency context of an overt act of terrorism. This paper reviews some of the literature concerning how social work responds to confl ict and terrorism before reporting a smallscale qualitative study examining the views of social work students, on a qualifying programme in the UK, of terrorism and the need for knowledge and understanding as part of their education

    History of Stepped Channels and Spillways: a Rediscovery of the 'Wheel'

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    Recently, spillways with a stepped profile have regained interest and favor among design engineers to pass flood waters over the dams. The stepped geometry enhances the energy dissipation above the spillway and reduces the size of a downstream stilling basin. In this paper, the author shows that the technique of stepped channels has been developed since Antiquity. Spillways and irrigation channels with stepped profiles were developed by several civilisations around the Mediterranean sea and in America. The main characteristics of the stepped spillways along the ages suggest a regular evolution rather than a revolution. Present stepped spillways are designed to pass similar discharges as two hundred years ago
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