4,757 research outputs found

    How a single stretched polymer responds coherently to a minute oscillation in fluctuating environments: An entropic stochastic resonance

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    Within the cell, biopolymers are often situated in constrained, fluid environments, e.g., cytoskeletal networks, stretched DNAs in chromatin. It is of paramount importance to understand quantitatively how they, utilizing their flexibility, optimally respond to a minute signal, which is, in general, temporally fluctuating far away from equilibrium. To this end, we analytically study viscoelastic response and associated stochastic resonance in a stretched single semi-flexible chain to an oscillatory force or electric field. Including hydrodynamic interactions between chain segments, we evaluate dynamics of the polymer extension in coherent response to the force or field. We find power amplification factor of the response at a noise-strength (temperature) can attain the maximum that grows as the chain length increases, indicative of an entropic stochastic resonance (ESR). In particular for a charged chain under an electric field, we find that the maximum also occurs at an optimal chain length, a new feature of ESR. The hydrodynamic interaction is found to enhance the power amplification, representing unique polymer cooperativity which the fluid background imparts despite its overdamping nature. For the slow oscillatory force, the resonance behavior is explained by the chain undulation of the longest wavelength. This novel ESR phenomenon suggests how a biopolymer self-organizes in an overdamping environment, utilizing its flexibility and thermal fluctuations

    Radiculopathy as Delayed Presentations of Retained Spinal Bullet.

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    Bullet injuries to the spine may cause injury to the anatomical structures with or without neurologic deterioration. Most bullet injuries are acute, resulting from direct injury. However, in rare cases, delayed injury may occur, resulting in claudication. We report a case of intradural bullet at the L3-4 level with radiculopathy in a 30-year-old male. After surgical removal, radicular and claudicating pain were improved significantly, and motor power of the right leg also improved. We report the case of intradural bullet, which resulted in delayed radiculopathy

    Assets, ‘Asset?ness’ and Graduation

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    Asset?based approaches – usually involving asset transfers and/or asset building – are increasingly central to thinking about poverty alleviation, social protection, graduation and livelihood resilience. Although the notion of assets is well established in the literature, the meanings of and relationships between asset(s), livelihood capital(s), risks(s), welfare and wellbeing, and graduation need further analysis. We examine issues arising from asset?based approaches to poverty reduction and introduce the idea of ‘asset?ness’ – the qualities and characteristics of different assets – which have received little attention from those promoting or designing asset?based social protection programmes. We argue that asset?ness provides a key to understanding differences in the impacts of asset?based social protection and associated processes and dynamics of graduation. As such the article aims to advance understanding of graduation theory. We develop this argument with reference to domestic livestock, which are commonly distributed to poor people as part of asset?based poverty alleviation and social protection programmes

    Lymphangiography to treat postoperative lymphatic leakage: a technical review.

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    In addition to imaging the lymphatics and detecting various types of lymphatic leakage, lymphangiography is a therapeutic option for patients with chylothorax, chylous ascites, and lymphatic fistula. Percutaneous thoracic duct embolization, transabdominal catheterization of the cisterna chyli or thoracic duct, and subsequent embolization of the thoracic duct is an alternative to surgical ligation of the thoracic duct. In this pictorial review, we present the detailed technique, clinical applications, and complications of lymphangiography and thoracic duct embolization

    Efekat uključivanja u hranljive smeše aditiva različitog porekla na rast, telesni sastav i otpornost mlađi crnog morskog grgeča (sebastes schlegeli)

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    U radu je tvrđen efekat uključivanja u hranljive smeše aditiva različitog porekla [đumbir (CG), fermentisana sojina pasta (CJ), borovnica (BB), japanska jabuka (PM), paradajz (TT), brokoli (BC) i jakon (YC)] na rast, telesni sastav i otpornost mlađi crnog morskog grgeča. Hiljadu šesto osamdeset riba je nasumično raspoređeno u 24 protočna tanka zapremine 200 L. Pripremljeno je osam oglednih smeša za ishranu: kontrolna bez dodataka (Con) i smeše sa dodatkom GG, CJ, BB, PM, TT, BC i YC. Svaka od smeša korišćena je u tri tanka, a ribe su 7 nedelja ručno hranjene do sitosti. Posle isteka ovog perioda, dvadeset riba iz svakog tanka inficirano je sa Streptococcus parauberis i praćeno narednih 10 dana. Prirast i specifična stopa rasta (SGR) bili su veći kod riba koje su u hrani dobijale jakon (YC) nego kod onih koje su hranjene drugim smešama. Kumulativni mortalitet do 5. dana posle infekcije bio je niži kod riba koje su hranjene smešama sa dodatkom GG, BB i YC nego kod ostalih jedinki. U zaključku, smeša sa dodatkom YC pokazala se kao najbolja u smislu poboljšanja prirasta i SGR kod crnog morskog grgeča. Osim toga, dodatak GG, BB i YC u smeše bio je najefikasniji u smanjivanju mortaliteta crnog morskog grgeča usled infekcije sa S. parauberi
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