Quantum orientational melting of mesoscopic clusters

By path integral Monte Carlo simulations we study the phase diagram of two - dimensional mesoscopic clusters formed by electrons in a semiconductor quantum dot or by indirect magnetoexcitons in double quantum dots. At zero (or sufficiently small) temperature, as quantum fluctuations of particles increase, two types of quantum disordering phenomena take place: first, at small values of quantum de Boer parameter q < 0.01 one can observe a transition from a completely ordered state to that in which different shells of the cluster, being internally ordered, are orientationally disordered relative to each other. At much greater strengths of quantum fluctuations, at q=0.1, the transition to a disordered (superfluid for the boson system) state takes place.Comment: 4 pages, 6 Postscript figure

Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential

The phase diagram of a two-dimensional Josephson array of mesoscopic objects is examined. Quantum fluctuations in both the modulus and phase of the superconducting order parameter are taken into account within a lattice boson Hubbard model. Modulating the average occupation number $n_0$ of the sites in the system leads to changes in the state of the array, and the character of these changes depends significantly on the region of the phase diagram being examined. In the region where there are large quantum fluctuations in the phase of the superconducting order parameter, variation of the chemical potential causes oscillations with alternating superconducting (superfluid) and normal states of the array. On the other hand, in the region where the bosons interact weakly, the properties of the system depend monotonically on $n_0$. Lowering the temperature and increasing the particle interaction force lead to a reduction in the width of the region of variation in $n_0$ within which the system properties depend weakly on the average occupation number. The phase diagram of the array is obtained by mapping this quantum system onto a classical two-dimensional XY model with a renormalized Josephson coupling constant and is consistent with our quantum Path-Integral Monte Carlo calculations.Comment: 12 pages, 8 Postscript figure

Pharmacoeconomic analysis of naft idrofuryl in patients with chronic obliterating diseases of lower limb arteries

Chronic obliterating diseases of lower limb arteries is a large group of socially significant diseases, characterized by persistent chronic progress, high probability of disabling complications as well as the emergence needs for expensive surgical treatment. This disease characterized by the association with other diseases of the cardiovascular system, making the conservative therapy especially relevant. Aim. To perform the pharmacoeconomic analysis (PHe) of the naft idrofuryl in the Russian Federation (RF) in patients aged 66 years and older with peripheral vascular disease, including atherosclerosis of the lower limbs arteries and the clinical picture, corresponding to Stage II of Fontaine. Methodology. Th is PHe is conducted perspective of public health organizations of the RF and considers only direct medical costs. Horizon of PHe adopted for 240 weeks (4.6 years). The source of data on the clinical eff ectiveness was taken from randomized controlled trials and meta-analyzes, which examined the efficacy, safety and tolerability comparable drugs. For criteria of clinical efficacy has been chosen the mean log expression of the maximum distance walk. As a criterion of utility were calculated the quality adjusted life years (QALY). In developed Markov model, the time horizon was broken down into a cycle of length for 1 week. On the basis of existing government standard of care was the assessment of costs in health care system for diagnosis and treatment in simulated groups, taking into consideration the cost of angioplasty. It was conducted cost-eff ectiveness (CEA), cost-utility (CUA), budget impact (BIA) and sensitivity analysis (SA), calculated cost-eff ectiveness threshold. Result. CER per patient at naft idrofuryl was 2,061 rubl., at pentoxifylline — 4,764 rubl. Since naft idrofuryl is not only superior to pentoxifylline in clinical effectiveness, but also was associated with a lower cost, the calculation of the ICER not needed. PHe show that CER per patient did not exceed the «willingness-to-pay ratio» none of the drugs, thus both of the drugs is relevant to reimbursement system. CUA demonstrated superiority naft idrofuryl both in terms of the net impact on the QALY, and in terms of utility costs (CUR), CUR of naft idrofuryl per patient totaled 144,992 rubl., pentoxifylline — 213,854 rubl. SA confi rmed the stability of these results. Analysis of BIA shows that the fi scal burden associated with naft idrofuryl, is lower by 183,9 million rubl. per year for every 3,000 treated patients on pentoxifylline, which can allow one to treat 1,321 patients more via a naft idrofuryl based therapeutic strategy. Conclusion. Excellence naft idrofuryl over pentoxifylline confi rmed in this pharmacoeconomic study. Naft idrofuryl dominates in terms of CER, CUR and reduce budget impact

High-precision measurements of krypton and xenon isotopes with a new static-mode quadrupole ion trap mass spectrometer

Measuring the abundance and isotopic composition of noble gases in planetary atmospheres can answer fundamental questions in cosmochemistry and comparative planetology. However, noble gases are rare elements, a feature making their measurement challenging even on Earth. Furthermore, in space applications, power consumption, volume and mass constraints on spacecraft instrument accommodations require the development of compact innovative instruments able to meet the engineering requirements of the mission while still meeting the science requirements. Here we demonstrate the ability of the quadrupole ion trap mass spectrometer (QITMS) developed at the Jet Propulsion Laboratory (Caltech, Pasadena) to measure low quantities of heavy noble gases (Kr, Xe) in static operating mode and in the absence of a buffer gas such as helium. The sensitivity reaches 10^(13) cps Torr^(−1) (about 10^(11) cps Pa^(−1)) of gas (Kr or Xe). The instrument is able to measure gas in static mode for extended periods of time (up to 48 h) enabling the acquisition of thousands of isotope ratios per measurement. Errors on isotope ratios follow predictions of the counting statistics and the instrument provides reproducible results over several days of measurements. For example, 1.7 × 10^(−10) Torr (2.3 × 10^(−8) Pa) of Kr measured continuously for 7 hours yielded a 0.6‰ precision on the ^(86)Kr/^(84)Kr ratio. Measurements of terrestrial and extraterrestrial samples reproduce values from the literature. A compact instrument based upon the QITMS design would have a sensitivity high enough to reach the precision on isotope ratios (e.g. better than 1% for ^(129,131–136)Xe/^(130)Xe ratios) necessary for a scientific payload measuring noble gases collected in the Venus atmosphere

КЛИНИКО-ЭКОНОМИЧЕСКАЯ ОЦЕНКА ИСПОЛЬЗОВАНИЯ ИНГАЛЯЦИОННЫХ АНЕСТЕТИКОВ

Sevoflurane is one of the widely used inhalation anesthetics as well as desflurane, which started to be used in Russia in 2012. These drugs possess similar properties; however, desflurane provides faster restoration of cognitive functions and reduces the time to extubation. This study was aimed to investigate the impact of properties of these medications on pharmacoeconomic parameters. The objective is to evaluate pharmacoeconomic parameters of anesthesia with desflurane and sevoflurane in a medical unit, investigating their impact on the performance of surgical teams and opportunity to introduce Fast-track surgery in the Russian Federation. Methods. For the purpose of cost-effectiveness analysis (CEA), the time period for simulation of the compared regimens made 1 year. And the time period for budget impact analysis (BIA) and additional analysis of Fast-Track surgery made 3 years. Results of randomized clinical trials were used as a source of data on safety and clinical efficiency. The simulated groups (100 patients each) were formed for the purpose of analysis. The decision tree was used, including all direct medical costs of anesthesia, and surgery in general (dextral hemicolectomy was analyzed). The number of surgeries performed in case of the maximum load in a medical unit was used as an efficiency criterion for CEA, and the full scope of costs for additional surgeries was also included. Result: Desflurane demonstrated maximum absolute efficiency, expressed as the number of surgeries in case of the maximum load in a medical unit, i.e. the best rate of cost-effectiveness (CER). CER for the regimen with desflurane made 63,251 RUR and CER for the one with sevoflurane made 63,841 RUR, The budget impact analysis showed that use of desflurane reduced the budget costs by 153,467 RUR during 3 years (provided that there are 247 surgeries per year and 3 surgeries per day). Sensitivity analysis confirmed the invariance of the obtained results. Analysis of potential introduction of Fast-Track surgeries showed that its use was associated with reduction of budget costs by 8,013,182 RUR. Conclusion: Use of anesthesia with desflurane resulted in higher effectiveness and was the most cost-effective providing reduction of budget costs. Одним из распространенных современных ингаляционных анестетиков является севофлуран, а также появившийся в российской практике в 2012 г. десфлуран. Данные препараты обладают во многом схожими свойствами, однако десфлуран обеспечивает более раннее восстановление когнитивных функций и сокращает время до экстубации. Влияние этих свойств на фармакоэкономические показатели и стало предметом данного исследования. Цель: оценить фармакоэкономические характеристики анестезии с применением десфлурана и севофлурана в медицинской организации (МО) с изучением влияния на производительность хирургической бригады, а также на возможность внедрения Fast-Track-протокола в условиях РФ. Методика. Горизонт моделирования для сравниваемых схем не превышал 1 года для анализа «затраты–эффективность» (CEA). Для анализа влияния на бюджет (BIA) и дополнительного анализа Fast-Track-протокола горизонт составил 3 года. В качестве источника данных о безопасности и клинической эффективности использованы результаты рандомизированных клинических исследований. Для анализа сформированы симулируемые группы (по 100 пациентов в каждой). Использована модель «древо принятия решений», учитывавшая прямые медицинские затраты на анестезию, а также на хирургическое вмешательство в целом (анализ выполняли при правосторонней гемиколэктомии). В качестве критерия эффективности в рамках СЕА использовано число операций, проводимых при условии максимальной загрузки МО, при этом учитывался также полный объем затрат на дополнительные операции. Результат. Десфлуран показал наибольшую абсолютную эффективность, выраженную как число операций при условии максимальной загрузки МО, и наибольшую эффективность затрат, т. е. наименьший показатель «затраты–эффективность» (СЕR). Показатель СЕR для схемы на основе десфлурана составил 63 251 руб., а севофлурана – 63 841 руб. Анализ влияния на бюджет показал, что использование десфлурана снижает бюджетное бремя на 153 467 руб. за 3 года (при условии 247 операционных дней в год и нагрузки – 3 операции в день). Анализ чувствительности подтвердил устойчивость полученных результатов. Анализ гипотетического внедрения Fast-Track-методологии показал, что его применение ассоциировано со снижением бюджетного бремени на 8 013 182 руб. Вывод. Применение анестезиологических схем на основе десфлурана показало большую эффективность с наилучшим показателем «затраты–эффективность» и снижение бюджетного бремени.

Vimentin is a novel AKT1 target mediating motility and invasion.

The PI3K/AKT signaling pathway is aberrant in a wide variety of cancers. Downstream effectors of AKT are involved in survival, growth and metabolic-related pathways. In contrast, contradictory data relating to AKT effects on cell motility and invasion, crucial prometastatic processes, have been reported pointing to a potential cell type and isoform type-specific AKT-driven function. By implication, study of AKT signaling should optimally be conducted in an appropriate intracellular environment. Prognosis in soft-tissue sarcoma (STS), the aggressive malignancies of mesenchymal origin, is poor, reflecting our modest ability to control metastasis, an effort hampered by lack of insight into molecular mechanisms driving STS progression and dissemination. We examined the impact of the cancer progression-relevant AKT pathway on the mesenchymal tumor cell internal milieu. We demonstrate that AKT1 activation induces STS cell motility and invasiveness at least partially through a novel interaction with the intermediate filament vimentin (Vim). The binding of AKT (tail region) to Vim (head region) results in Vim Ser39 phosphorylation enhancing the ability of Vim to induce motility and invasion while protecting Vim from caspase-induced proteolysis. Moreover, vimentin phosphorylation was shown to enhance tumor and metastasis growth in vivo. Insights into this mesenchymal-related molecular mechanism may facilitate the development of critically lacking therapeutic options for these devastating malignancies

Correlation functions near Modulated and Rough Surfaces

In a system with long-ranged correlations, the behavior of correlation functions is sensitive to the presence of a boundary. We show that surface deformations strongly modify this behavior as compared to a flat surface. The modified near surface correlations can be measured by scattering probes. To determine these correlations, we develop a perturbative calculation in the deformations in height from a flat surface. Detailed results are given for a regularly patterned surface, as well as for a self-affinely rough surface with roughness exponent $\zeta$. By combining this perturbative calculation in height deformations with the field-theoretic renormalization group approach, we also estimate the values of critical exponents governing the behavior of the decay of correlation functions near a self-affinely rough surface. We find that for the interacting theory, a large enough $\zeta$ can lead to novel surface critical behavior. We also provide scaling relations between roughness induced critical exponents for thermodynamic surface quantities.Comment: 31 pages, 2 figure

Public political narratives: developing a neglected source through the exploratory case of Russia in the Putin-Medvedev era

The place of narrative in political science is an issue that resurfaces with regularity, usually focusing on the questions of generalisability, evidence and causality which lie at the heart of the discipline. Most such debate concerns the use of narrative by political scientists. Far less attention has been devoted to the use of narrative by political actors, despite its relative ubiquity. Even where such attention has been given, it concentrates less on the narrative per se, and more on its performance and impact. However, the nature of public political narratives means that analysis of them facilitates a holistic understanding of their narrators' politics. A public political narrative consists of a sequential account given by political actors connecting selected, specific developments so as to impose a desired order on them. Taking contemporary Russia as an exploratory case, narrative analysis draws out the motivations, world view and inconsistencies within the Putin-Medvedev regime. Recurring motifs and symbols identify the regime's political priorities, explaining policy choices and revealing future concerns. Narrative has a predictive aspect, identifying likely policy responses to unexpected events. Narratives capture time, and shifts in their temporalities indicate changes in self-conceptualisation and political priorities. Temporal appropriations include or exclude particular agential and causal explanations. The relationship between their plots and subplots represents a political signalling process. Public political narratives provide temporally and spatially specific exceptionalist accounts, but their combinatory quality also facilitates comparative analysis. The approach essayed here provides methodological generalisability, arguing that the neglect of public political narratives merits correcting

Vortex lattice disorder in YBCO probed using Beta-NMR

Beta-NMR has been used to study vortex lattice disorder near the surface of the high-Tc superconductor YBCO. The magnetic field distribution from the vortex lattice was detected by implanting a low energy beam of highly polarized 8Li into a thin overlayer of silver on optimally doped, twinned and detwinned YBCO samples. The resonance in Ag broadens significantly below the transition temperature Tc as expected from the emerging field lines of the vortex lattice in YBCO. However, the lineshape is more symmetric and the dependence on the applied magnetic field is much weaker than expected from an ideal vortex lattice, indicating that the vortex density varies across the face of the sample, likely due to pinning at twin boundaries. At low temperatures the broadening from such disorder does not scale with the superfluid density.Comment: 10 pages, 6 figure