Uncertainty relations in curved spaces

Uncertainty relations for particle motion in curved spaces are discussed. The relations are shown to be topologically invariant. New coordinate system on a sphere appropriate to the problem is proposed. The case of a sphere is considered in details. The investigation can be of interest for string and brane theory, solid state physics (quantum wires) and quantum optics.Comment: published version; phase space structure discussion adde

Topological effects in the thermal properties of knotted polymer rings

The topological effects on the thermal properties of several knot configurations are investigated using Monte Carlo simulations. In order to check if the topology of the knots is preserved during the thermal fluctuations we propose a method that allows very fast calculations and can be easily applied to arbitrarily complex knots. As an application, the specific energy and heat capacity of the trefoil, the figure-eight and the $8_1$ knots are calculated at different temperatures and for different lengths. Short-range repulsive interactions between the monomers are assumed. The knots configurations are generated on a three-dimensional cubic lattice and sampled by means of the Wang-Landau algorithm and of the pivot method. The obtained results show that the topological effects play a key role for short-length polymers. Three temperature regimes of the growth rate of the internal energy of the system are distinguished.Comment: 7 pages, 12 figures, LaTeX + RevTeX. With respect to the first version, in the second version the text has been improved and all figures are now in black and whit

Polygonal Structures in the Gaseous Disk: Numerical Simulations

The results of numerical simulations of a gaseous disk in the potential of a stellar spiral density wave are presented. The conditions under which straightened spiral arm segments (rows) form in the gas component are studied. These features of the spiral structure were identified in a series of works by A.D. Chernin with coauthors. Gas-dynamic simulations have been performed for a wide range of model parameters: the pitch angle of the spiral pattern, the amplitude of the stellar spiral density wave, the disk rotation speed, and the temperature of the gas component. The results of 2D- and 3D-disk simulations are compared. The rows in the numerical simulations are shown to be an essentially nonstationary phenomenon. A statistical analysis of the distribution of geometric parameters for spiral patterns with rows in the observed galaxies and the constructed hydrodynamic models shows good agreement. In particular, the numerical simulations and observations of galaxies give $\simeq 120^\circ$ for the average angles between straight segments.Comment: 22 pages, 10 figure

Choice of Tool Material for Frictional Surface Hardening of Structural Steels

Обоснована возможность применения твердого сплава WC–Co (10 %) с хромом Cr (0,4 %) в качестве ингибитора роста зерен при фрикционной поверхностной закалке углеродистых и легированных сталей. Получены зависимости температуропроводности и теплопроводности материала инструмента в диапазоне температур 25…1050 °C.The possibility of using the hard alloy WC–Co (10 %) with chromium Cr (0.4 %) as a grain growth inhibitor in frictional surface hardening of carbon and alloy steels is substantiated. Dependences of thermal diffusivity and thermal conductivity of the tool material are obtained in the temperature range of 25…1050 °C

Revealing weak A and B antigens in patients with knee and hip joint arthroplasty

АНТИГЕНЫКРОВЬАНТИТЕЛА АНТИИДИОТИПИЧЕСКИЕАНТИ-АНТИТЕЛААНТИГАММА-ГЛОБУЛИНОВЫЕ АНТИТЕЛААНТИГЛОБУЛИНЫАНТИИДИОТИПНЫЕ АНТИТЕЛАКОМПЛЕМЕНТКОМПЛЕМЕНТБЕЛКИ КОМПЛЕМЕНТАРНЫЕКОМПЛЕМЕНТА БЕЛКИЭРИТРОЦИТЫЦель. Провести анализ методов выявления слабых А и В антигенов на эритроцитах в системе АВ0. Материал и методы. Проведено обследование пациентов с эндопротезированием коленного и тазобедренного суставов с целью определения группоспецифической принадлежности с выявлением слабых А и В антигенов на эритроцитах. Использованы методы абсорбции, реакция агглютинации, агглютинация в присутствии комплемента и антиглобулиновый тест. Результаты. Антиглобулиновый тест с использованием как поликлональной сыворотки, так и сыворотки, содержащей только IgG антитела, позволил выявить слабые A и B подгруппы на эритроцитах при 37{o}С. В реакции абсорбции с анти-А, анти-В поликлональными сыворотками у некоторых пациентов на эритроцитах выявлены А и В антигены, также проявившиеся в реакции агглютинации при 37{o}С, но не обнаруженные при инкубации при комнатной температуре. Агглютинационный тест с использованием комплемента и сыворотки с IgG антителами также способствовал проявлению слабых антигенов. Присутствие IgG антител было определено после обработки сыворотки унитиолом в антиглобулиновом тесте. Наличие в сыворотке только IgG антител, соответствующих антигенам, при участии комплемента приводило к более выраженным изменениям эритроцитов по сравнению с присутствием обоих классов антител – IgM и IgG. Появление гемолиза ассоциировалось с увеличением размеров эритроцитов и гипохромией. Присутствие слабых подгрупп в большинстве случаев было ассоциировано с гемолизирующими, а не агглютинирующими свойствами сыворотки пациента, а также наличием комплементсвязывающих IgG антител. Заключение. Применение абсорбции, агглютинация при 37{o}С, антиглобулиновый тест при 37{o}С с сывороткой, как подвергшейся, так и не подвергшейся обработке унитиолом, а также реакция агглютинации с использованием комплемента способствовали определению слабых антигенов в системе АВ0.Objective. To analyze the methods of revealing weak A and B antigens on the erythrocytes in AB0 system. Methods. Patients after knee and joint arthroplasty were examined on group-specific characteristics with revealing weak A and B antigens on the erythrocytes. Methods of absorption, agglutination, agglutination with complement and antiglobulin test were used. Results. Antiglobulin test with the use of polyclonal serum as well as serum containing the only IgG allowed revealing weak A and B subgroups on erythrocytes at 37{o}С. In some patients A and B antigens on erythrocytes were found while absorption with anti-A, anti-B polyclonal sera and also revealed in agglutination at 37{o}С, but were not revealed while incubation at the room temperature. Agglutination test with the use of complement and IgG was also helpful in determining the weak antigens. Presence of IgG antibodies was revealed by the treatment of the serum with unithiol in antiglobulin test. Presence of complement and only IgG antibodies corresponding to the antigens led to the more expressed changes of erythrocytes as compared to the presence of both types of antibodies – IgM and IgG. Appearance of hemolysis was associated with the increased sizes of erythrocytes and hypochromia. Presence of weak subgroups was mostly associated with hemolytic rather than agglutinating abilities of the patient’s serum, as well as with the presence of complement binding IgG antibodies. Conclusions. Absorption, agglutination at 37{o}С, antiglobulin test at 37{o}C with serum both treated and non-treated with unithiol and agglutination with use of the complement helped to define weak antigens in AB0 system

Dynamics of Quantum Collapse in Energy Measurements

The influence of continuous measurements of energy with a finite accuracy is studied in various quantum systems through a restriction of the Feynman path-integrals around the measurement result. The method, which is equivalent to consider an effective Schr\"odinger equation with a non-Hermitian Hamiltonian, allows one to study the dynamics of the wavefunction collapse. A numerical algorithm for solving the effective Schr\"odinger equation is developed and checked in the case of a harmonic oscillator. The situations, of physical interest, of a two-level system and of a metastable quantum-well are then discussed. In the first case the Zeno inhibition observed in quantum optics experiments is recovered and extended to nonresonant transitions, in the second one we propose to observe inhibition of spontaneous decay in mesoscopic heterostructures. In all the considered examples the effect of the continuous measurement of energy is a freezing of the evolution of the system proportional to the accuracy of the measurement itself.Comment: 20 pages with figures, compressed and uuencoded ps fil

Gap symmetry and structure of Fe-based superconductors

The recently discovered Fe-pnictide and chalcogenide superconductors display low-temperature properties suggesting superconducting gap structures which appear to vary substantially from family to family, and even within families as a function of doping or pressure. We propose that this apparent nonuniversality can actually be understood by considering the predictions of spin fluctuation theory and accounting for the peculiar electronic structure of these systems, coupled with the likely 'sign-changing s-wave' (s\pm) symmetry. We review theoretical aspects, materials properties and experimental evidence relevant to this suggestion, and discuss which further measurements would be useful to settle these issues.Comment: 86 pages, revie

Linker-extended native cyanovirin-N facilitates PEGylation and potently inhibits HIV-1 by targeting the glycan ligand

Cyanovirin-N (CVN) potently inhibits human immunodeficiency virus type 1 (HIV-1) infection, but both cytotoxicity and immunogenicity have hindered the translation of this protein into a viable therapeutic. A molecular docking analysis suggested that up to 12 residues were involved in the interaction of the reverse parallel CVN dimer with the oligosaccharide targets, among which Leu-1 was the most prominent hot spot residue. This finding provided a possible explanation for the lack of anti-HIV-1 activity observed with N-terminal PEGylated CVN. Therefore, linker-CVN (LCVN) was designed as a CVN derivative with a flexible and hydrophilic linker (Gly4Ser)3 at the N-terminus. The N-terminal α-amine of LCVN was PEGylated to create 10 K PEG-aldehyde (ALD)-LCVN. LCVN and 10 K PEG-ALD-LCVN retained the specificity and affinity of CVN for high mannose N-glycans. Moreover, LCVN exhibited significant anti-HIV-1 activity with attenuated cytotoxicity in the HaCaT keratinocyte cell line and MT-4 T lymphocyte cell lines. 10 K PEG-ALD-LCVN also efficiently inactivated HIV-1 with remarkably decreased cytotoxicity and pronounced cell-to-cell fusion inhibitory activity in vitro. The linker-extended CVN and the mono-PEGylated derivative were determined to be promising candidates for the development of an anti-HIV-1 agent. This derivatization approach provided a model for the PEGylation of biologic candidates without introducing point mutations. © 2014 Chen et al

Application of transradial and transfemoral accesses during hepatic artery chemoembolization in the treatment of patients with malignant liver neoplasms

Introduction Malignant neoplasms of the liver are one of the most common pathologies in oncology. Chemoembolization of the hepatic artery is currently widely used in the treatment of unresectable liver tumors. Transradial vascular access is actively used in interventional cardiology due to fewer local vascular complications. At the same time, until recently, chemoembolization of the hepatic artery was more often performed via transfemoral vascular access. The aim of the work is a comparative analysis of the results of transradial and transfemoral vascular accesses for the purpose of hepatic artery chemoembolization. Material and methods The data of 69 patients who underwent 212 hepatic artery chemoembolization procedures for malignant neoplasms in the liver were analyzed. The group of transradial access included 107 (50.5 %) interventions, the group of transfemoral access – 105 (49.5 %). The groups were comparable in terms of the main initial clinical and anamnestic data. Results Chemoembolization of the hepatic artery was successfully performed in 98.1 % in the transradial access group and 99 % in the transfemoral access group (p = 1.0). The total duration of intervention, time spent on catheterization of the target artery and radiation exposure were significantly shorter in the transradial access group than in the opposite group. The incidence of local vascular complications was not significantly different between the groups: 11 (10.3 %) and 12 (11.4 %) cases, respectively (p = 0.79). According to the results of patient interviews, the use of transradial access was accompanied by significantly less discomfort associated with the procedure. Discussion Traditionally, embolization of peripheral arteries is performed via transfemoral access, and the total incidence of local vascular complications (large subcutaneous hematomas, false aneurysms, arterovenous fistulas, etc.) is relatively high. According to the results of studies, it is possible to reduce the incidence of local vascular complications without increasing the cost of the procedure by performing the same interventions using transradial access. Conclusion Transradial vascular access has a number of significant advantages over transfemoral access, and therefore can be recommended as a priority for performing hepatic artery chemoembolization.Введение. Злокачественные новообразования печени являются одной из наиболее часто встречающихся патологий в онкологии. Химиоэмболизация печеночной артерии в настоящее время широко применяется в лечении нерезектабельных опухолей печени. Трансрадиальный сосудистый доступ активно используется в интервенционной кардиологии в связи с меньшим числом локальных сосудистых осложнений. До недавнего времени химиоэмболизация печеночной артерии чаще выполнялась через трансфеморальный сосудистый доступ. Цель работы – сравнительный анализ результатов применения трансрадиального и трансфеморального сосудистых доступов с целью химиоэмболизации печеночной артерии. Материалы и методы. Проанализированы данные 69 пациентов, которым было выполнено 212 процедур химиоэмболизации печеночной артерии по поводу злокачественных новообразований в печени. В группу трансрадиального доступа вошли 107 (50,5 %) вмешательств, в группу трансфеморального доступа – 105 (49,5 %). По основным исходным клинико-анамнестическим данным указанные группы были сопоставимы. Результаты. Химиоэмболизация печеночной артерии была успешно выполнена в 98,1 % в группе трансрадиального доступа и в 99 % случаев в группе трансфеморального доступа (р = 1,0). Общая продолжительность вмешательства, время, потраченное на катетеризацию целевой артерии, и лучевая нагрузка были достоверно меньше в группе трансрадиального доступа. Частота местных сосудистых осложнений достоверно не различалась между группами: 11 (10,3 %) и 12 (11,4 %) случаев соответственно (р = 0,79). По результатам опроса пациентов, использование трансрадиального доступа сопровождалось достоверно меньшей выраженностью дискомфорта, связанного с процедурой. Обсуждение. Традиционно эмболизация периферических артерий выполняется через трансфеморальный доступ, при этом суммарная частота развития местных сосудистых осложнений (больших подкожных гематом, ложных аневризм, артериовенозных фистул и пр.) относительно высока. Снизить частоту развития местных сосудистых осложнений без увеличения себестоимости процедуры позволяет выполнение тех же вмешательств с использованием трансрадиального доступа. Заключение. Трансрадиальный сосудистый доступ имеет ряд существенных преимуществ по сравнению с трансфеморальным, в связи с чем может быть рекомендован в качестве приоритетного для выполнения химиоэмболизации печеночной артерии