A quantum fluid of metallic hydrogen suggested by first-principles calculations

It is generally assumed that solid hydrogen will transform into a metallic alkali-like crystal at sufficiently high pressure. However, some theoretical models have also suggested that compressed hydrogen may form an unusual two-component (protons and electrons) metallic fluid at low temperature, or possibly even a zero-temperature liquid ground state. The existence of these new states of matter is conditional on the presence of a maximum in the melting temperature versus pressure curve (the 'melt line'). Previous measurements of the hydrogen melt line up to pressures of 44 GPa have led to controversial conclusions regarding the existence of this maximum. Here we report ab initio calculations that establish the melt line up to 200 GPa. We predict that subtle changes in the intermolecular interactions lead to a decline of the melt line above 90 GPa. The implication is that as solid molecular hydrogen is compressed, it transforms into a low-temperature quantum fluid before becoming a monatomic crystal. The emerging low-temperature phase diagram of hydrogen and its isotopes bears analogies with the familiar phases of 3He and 4He, the only known zero-temperature liquids, but the long-range Coulombic interactions and the large component mass ratio present in hydrogen would ensure dramatically different propertiesComment: See related paper: cond-mat/041040

Синдром Мэя - Тернера: современные методы диагностики и лечения

May-Turner syndrome is a condition where the left common iliac vein is compressed between the lumbar spine and the overlying right common iliac artery. Left iliac vein compression is common (up to 24%) in the general population, but clinical manifestations occur in a few patients. This syndrome should be considered in case of unexplained edema of the left lower extremity since routine duplex ultrasound does not possess optimal sensitivity and specificity in the study of the iliac veins and the inferior vena cava. Intravascular ultrasound is the most accurate diagnostic method. However, the advent of computed tomography angiography and magnetic resonance angiography providing high-quality images of the vasculature have become a promising alternative to invasive intravascular ultrasound. Treatment for May-Turner syndrome usually involves stenting of the left common iliac vein along with medical therapy, including antithrombotic (anticoagulant and antiplatelet) therapy combined with phlebotonics. Our review reports modern methods of diagnosis and treatment of May-Turner syndrome.Синдром Мэя - Тернера (СМТ) является симптомокомплексом, который возникает при сдавлении левой общей подвздошной вены между поясничным отделом позвоночника и правой общей подвздошной артерией. Компрессия левой общей подвздошной вены распространена в общей популяции (24%), однако клинические проявления наступают у значительно меньшего количества пациентов. Заподозрить данный синдром следует при необъяснимом отеке левой нижней конечности, так как классическое ультразвуковое дуплексное сканирование не обладает необходимыми чувствительностью и специфичностью при исследовании подвздошных вен и нижней полой вены. Внутрисосудистое ультразвуковое исследование (ВСУЗИ) является наиболее точным методом диагностики, однако компьютерная томографическая и магнитно-резонансная ангиографии с высоким качеством изображения представляют эффективную альтернативу инвазивному ВСУЗИ. Основным методом лечения СМТ является стентирование левой общей подвздошной вены на фоне приема медикаментозной терапии, включающей антитромбо-тическую (антикоагулянтную и антиагрегантную) терапию в комбинации с флеботонизирующими препаратами. Цель данного обзора состоит в описании современных методов диагностики и лечения синдрома Мэя - Тернера

Polarizable Water Model for the Coarse-Grained MARTINI Force Field

Coarse-grained (CG) simulations have become an essential tool to study a large variety of biomolecular processes, exploring temporal and spatial scales inaccessible to traditional models of atomistic resolution. One of the major simplifications of CG models is the representation of the solvent, which is either implicit or modeled explicitly as a van der Waals particle. The effect of polarization, and thus a proper screening of interactions depending on the local environment, is absent. Given the important role of water as a ubiquitous solvent in biological systems, its treatment is crucial to the properties derived from simulation studies. Here, we parameterize a polarizable coarse-grained water model to be used in combination with the CG MARTINI force field. Using a three-bead model to represent four water molecules, we show that the orientational polarizability of real water can be effectively accounted for. This has the consequence that the dielectric screening of bulk water is reproduced. At the same time, we parameterized our new water model such that bulk water density and oil/water partitioning data remain at the same level of accuracy as for the standard MARTINI force field. We apply the new model to two cases for which current CG force fields are inadequate. First, we address the transport of ions across a lipid membrane. The computed potential of mean force shows that the ions now naturally feel the change in dielectric medium when moving from the high dielectric aqueous phase toward the low dielectric membrane interior. In the second application we consider the electroporation process of both an oil slab and a lipid bilayer. The electrostatic field drives the formation of water filled pores in both cases, following a similar mechanism as seen with atomistically detailed models

INCOMPLETE PROJECT of the ENLIGHTENMENT: METHODOLOGICAL ASPECT

A search for ways to overcome modern methodological crisis of humanitarian knowledge is one of the most urgent and pressing research challenges. Its solution, on one hand, must ensure the breakthrough of humanitaristics towards new clearly visible but still not yet developed boundaries. On the other hand, the crisis in question is so extensive that it seems there is no possibility to overcome it. The way out of the crisis to the post-crisis stage is found in a traditional way: by making a clear diagnosis. Clarification of it paradoxically allows us to find support for a methodological breakthrough in the very painful "nerve" of the crisis. Spiritual freedom of personality acquired in XX century is a notion included in textbooks but not yet incorporated into the framework of categories and concepts of modern methodology. Detailed analysis shows that this category specifically, concretized by a series of definitions, can change our perspective on the ways of overcoming the methodological crisis. In this context, the view on the Enlightenment, which methodological potential is far from being exhausted, changes significantly. Moreover, it is absolutely clear that humanity is facing the necessity and imminence of its new turn

Successful endoscopic treatment of diverticular disease complicated by paracolic abscess

Aim of clinical case presentation. To evaluate potential of intraluminal endoscopy for the treatment of diverticulitis, complicated by paracolic abscess. Summary. The clinical case of complicated colonic diverticula treatment by intraluminal endoscopy is presented. Patient at urgent admission was diagnosed to have “strangulated postoperative ventral hernia”; however the complex laboratory and instrumental investigations revealed inflammatory infiltrate in the right iliac area with signs of abscess formation. Attempts to carry out abscess drainage under ultrasound control were unsuccessful. To rule out potential neoplastic disease and determine the scope of surgical intervention videoassisted colonoscopy was carried out that revealed ascending colon diverticulum as a cause for paracolic abscess. Results. Endoscopic procedure provided successful surgical intervention that resulted in adequate internal drainage of the abscess was subsequent resolution of inflammatory infiltrate and complete patient recovery. Conclusion. Internal endoscopic drainage of the paracolic abscess that developed on the background of colonic diverticulitis can be successful alternative to urgent surgery due to reduction of treatment cost and improvement of quality of life of patients