Сравнение электрохирургического и радиоволнового способов эксцизии полипов желудка

The work is based on the analysis of treatment of 162 patients with gastric polyps. A comparative analysis of electrosurgical and radio-wave methods of polypectomy was performed. The both methods of excision of gastric polyps were equally effective, and radio-wave polypectomy was accompanied by less number of complications. The results of long-term follow up propose a lower rate of recurrent polyps after radio-wave polypectomy.Статья посвящена актуальной проблеме эндоскопического лечения полипов желудка. В исследование включено 162 пациента с полипами желудка. Проведен сравнительный анализ электрохирургического и радиоволнового способов удаления полипов желудка. Оба способа эксцизии полипов желудка продемонстрировали сходную эффективность при меньшем уровне послеоперационных кровотечений после радиоволновой полипэктомии. Кроме того, применение радиоволнового способа эксцизии полипов желудка позволяет, по данным отдаленного обследования пациентов, уменьшить вероятность развития рецидивов полипов желудка

X-ray and neutron diffraction studies of coupled structural phase transitions in DyBaCo2_{2}O5.5_{5.5}

A structural transition at $T\approx 322$ K from the $Pmmm$ to $Pmma$ phase is found to coincide with an anomaly of resistivity. Another structural phase transition doubling the lattice parameter $c$, which has been postulated earlier to accompany a low-temperature magnetic transition in TbBaCo$_{2}$O$_{5.5}$, is observed in a single crystal DbBaCo$_{2}$O$_{5.5}$ by means of the X-ray and neutron diffraction. The low temperature phase does not belong to the space group $Pcca$ that has been chosen earlier as the highest subgroup of the $Pmma$. The transition is of the first order with the temperature hysteresis, between $T\approx 100$ and $T\approx 200$ K, which probably explains anomalous magnetic properties in this temperature range.Comment: 6 pages, 4 figure

Выбор оптимального метода лечения больных с синдромом Мириззи

Retrospective analysis of treatment of 53 patients with Mirizzi syndrome was made. Diagnostic algorithm included transabdominal ultrasound - 53 (100%), ERCP - 39 (74%). Surgery was performed in 35 patients, in 21 (40%) cases - after endoscopic intervention. Post - ERCP complications were observed in 2 (5,1%) patients, complications after surgery - 2 (5,7%) patients. Lethality was 3 (6,7%).Проведен ретроспективный анализ лечения 53 пациентов с синдромом Мириззи. Диагностический алгоритм у 53 больных включал: УЗИ - 53 (100%) пациентам, ЭРХПГ - в 39 (74,0%) случаях. Оперированы 35 больных, из них 21 (40%) пациент после эндоскопических вмешательств. Осложнения после ЭРХПГ отмечены у 2 (5,1%) пациентов, после хирургических вмешательств осложнения выявлены в 2 (5,7%) случаях. Летальность составила 3 (6,7%)

Bound Chains of Tilted Dipoles in Layered Systems

Ultracold polar molecules in multilayered systems have been experimentally realized very recently. While experiments study these systems almost exclusively through their chemical reactivity, the outlook for creating and manipulating exotic few- and many-body physics in dipolar systems is fascinating. Here we concentrate on few-body states in a multilayered setup. We exploit the geometry of the interlayer potential to calculate the two- and three-body chains with one molecule in each layer. The focus is on dipoles that are aligned at some angle with respect to the layer planes by means of an external eletric field. The binding energy and the spatial structure of the bound states are studied in several different ways using analytical approaches. The results are compared to stochastic variational calculations and very good agreement is found. We conclude that approximations based on harmonic oscillator potentials are accurate even for tilted dipoles when the geometry of the potential landscape is taken into account.Comment: 10 pages, 6 figures. Submitted to Few-body Systems special issue on Critical Stability, revised versio

CONTINUOUS PALEOENVIRONMENTAL SEDIMENT RECORD FROM TWO LAKES ON VALDAY ICE MARGINAL ZONE STARTED SHORTLY AFTER THE ICE RETREAT

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Thermodynamics of Dipolar Chain Systems

The thermodynamics of a quantum system of layers containing perpendicularly oriented dipolar molecules is studied within an oscillator approximation for both bosonic and fermionic species. The system is assumed to be built from chains with one molecule in each layer. We consider the effects of the intralayer repulsion and quantum statistical requirements in systems with more than one chain. Specifically, we consider the case of two chains and solve the problem analytically within the harmonic Hamiltonian approach which is accurate for large dipole moments. The case of three chains is calculated numerically. Our findings indicate that thermodynamic observables, such as the heat capacity, can be used to probe the signatures of the intralayer interaction between chains. This should be relevant for near future experiments on polar molecules with strong dipole moments.Comment: 15 pages, 5 figures, final versio

Preparation of facilities for fundamental research with ultracold neutrons at PNPI

The WWR-M reactor of PNPI offers a unique opportunity to prepare a source for ultracold neutrons (UCN) in an environment of high neutron flux (about 3*10^12 n/cm^2/s) at still acceptable radiation heat release (about 4*10^-3 W/g). It can be realized within the reactor thermal column situated close to the reactor core. With its large diameter of 1 m, this channel allows to install a 15 cm thick bismuth shielding, a graphite premoderator (300 dm^3 at 20 K), and a superfluid helium converter (35 dm^3). At a temperature of 1.2 K it is possible to remove the heat release power of about 20 W. Using the 4pi flux of cold neutrons within the reactor column can bring more than a factor 100 of cold neutron flux incident on the superfluid helium with respect to the present cold neutron beam conditions at the ILL reactor. The storage lifetime for UCN in superfluid He at 1.2 K is about 30 s, which is sufficient when feeding experiments requiring a similar filling time. The calculated density of UCN with energy between 50 neV and 250 neV in an experimental volume of 40 liters is about 10^4 n/cm^3. Technical solutions for realization of the project are discussed.Comment: 10 pages, more detail

Sub-collision hyperfine structure of nonlinear-optical resonance with field scanning

Some experimental evidences for methane are produced that the simple transition from frequency scanning of nonlinear-optical resonances to magnetic one may be accompanied with transition from sub-Doppler collisionally broadened structure to sub-collision hyperfine one. It is conditioned by nonlinearity of splitting of hyperfine sublevel for molecules in the adiabatically varied magnetic field and respectively breaking the analogy of magnetic and frequency scannings. The exact calculation of the resonance structure is considered for molecules with only one spin subsystem. The approximately spin-additive calculation of the structure is given for sufficiently fast rotating molecules with greater number of spin subsystems. Within the same approximation an example of hyperfine doubling in the magnetic and electric spectra of nonlinear-optical resonance is considered for fluoromethane.Comment: 56 pages, 10 figures, accepted for publication in J. Mol. Spectrosc

Density Waves in Layered Systems with Fermionic Polar Molecules

A layered system of two-dimensional planes containing fermionic polar molecules can potentially realize a number of exotic quantum many-body states. Among the predictions, are density-wave instabilities driven by the anisotropic part of the dipole-dipole interaction in a single layer. However, in typical multilayer setups it is reasonable to expect that the onset and properties of a density-wave are modified by adjacent layers. Here we show that this is indeed the case. For multiple layers the critical strength for the density-wave instability decreases with the number of layers. The effect depends on density and is more pronounced in the low density regime. The lowest solution of the instability corresponds to the density waves in the different layers being in-phase, whereas higher solutions have one or several adjancet layers that are out of phase. The parameter regime needed to explore this instability is within reach of current experiments.Comment: 7 pages, 4 figures. Final version in EPJD, EuroQUAM special issue "Cold Quantum Matter - Achievements and Prospects

Экспериментальное исследование антибактериальной активности литического стафилококкового бактериофага ph20 и литического бактериофага синегнойной палочки ph57 при моделировании их импрегнации в ортопедические полимерные конструкции из полиметилметакрилата (костного цемента)

Background: The problem of bacterial colonization of implants used in medical practice continues to be relevant regardless of the material of the implant. Particular attention deserves polymeric implants, which are prepared ex tempore from polymethyl methacrylate, for example - duting orthopedic surgical interventions (so-called "bone cement"). The protection of such implants by antibiotic impregnation is subjected to multiple criticisms, therefore, as an alternative to antibiotics, lytic bacteriophages with a number of unique advantages can be used - however, no experimental studies have been published on the possibility of impregnating bacteriophages into polymethyl methacrylate and their antibacterial activity assessment under such conditions.Aims: to evaluate the possibility of physical placement of bacteriophages in polymethylmethacrylate and to characterize the lytic antibacterial effect of two different strains of bacteriophages when impregnated into polymer carrier ex tempore during the polymerization process in in vitro model.Materials and methods:  First stage - Atomic force microscopy (AFM) of polymethyl methacrylate samples for medical purposes was used to determine the presence and size of caverns in polymethyl methacrylate after completion of its polymerization at various reaction  temperatures (+6…+25°C and +18…+50°C).The second stage was performed in vitro and included an impregnation of two different bacteriophage strains (phage ph20 active against S. aureus and ph57 active against Ps. aeruginosa) into polymethyl methacrylate during the polymerization process, followed by determination of their antibacterial activity.Results: ACM showed the possibility of bacteriophages placement in the cavities of polymethyl methacrylate - the median of the section and the depth of cavities on the outer surface of the polymer sample polymerized at +18…+50°C were 100.0 and 40.0 nm, respectively, and on the surface of the transverse cleavage of the sample - 120.0 and 100.0 nm, respectively, which statistically did not differ from the geometric dimensions of the caverns of the sample polymerized at a temperature of +6…+25°C.The study of antibacterial activity showed that the ph20 bacteriophage impregnated in polymethyl methacrylate at +6…+25°C lost its effective titer within the first six days after the start of the experiment, while the phage ph57 retained an effective titer for at least 13 days.Conclusion: the study confirmed the possibility of bacteriophages impregnation into medical grade polymethyl methacrylate, maintaining the effective titer of the bacteriophage during phage emission into the external environment, which opens the way for the possible application of this method of bacteriophage delivery in clinical practice. It is also assumed that certain bacteriophages are susceptible to aggressive influences from the chemical components of "bone cement" and / or polymerization reaction products, which requires strict selection of bacteriophage strains that could be suitable for this method of delivery.Обоснование. Проблема бактериальной колонизации используемых в медицинской практике имплантатов из различных материалов продолжает оставаться актуальной, независимо от использованного для их изготовления материала. Отдельного внимания заслуживают имплантируемые в организм человека полимерные имплантаты, которые изготовляют ex tempore (по мере надобности) из полиметилметакрилата, например при ортопедических хирургических вмешательствах (так называемый костный цемент). Защита таких имплантатов путем импрегнации в них антибиотиков подвергается множественной критике, поэтому в качестве альтернативы антибиотикам могут быть использованы литические бактериофаги, обладающие рядом уникальных преимуществ, однако экспериментальных работ по изучению возможности импрегнации бактериофагов в полиметилметакрилат и антибактериальной активности в таких условиях в литературе не опубликовано. Цель исследования ― изучить возможность физического размещения бактериофагов в полиметилметакрилате и в модели in vitro охарактеризовать литический антибактериальный эффект двух различных штаммов бактериофагов при их импрегнации в изготавливаемый ex tempore полимерный носитель на этапе полимеризации. Методы. Первым этапом была проведена атомно-силовая микроскопия (АСМ) образцов полиметилметакрилата медицинского назначения для выяснения наличия и размеров каверн, образовавшихся после завершения полимеризации при различном диапазоне температур реакционной смеси (+6…+25 °C и +18…+50 °C). Вторым этапом in vitro было проведена импрегнация двух различных штаммов бактериофагов (ph20, активного в отношении Staphylococcus aureus, и ph57, активного в отношении Pseudomonas aeruginosa) в полиметилметакрилат на этапе полимеризации с последующим определением их антибактериальной активности. Результаты. В ходе выполнения АСМ установлена возможность размещения бактериофагов в кавернах полиметилметакрилата: медиана сечения и глубины каверн на внешней поверхности образца, полимеризованного при температуре +18…+50 °C, составила 100,0 и 40,0 нм соответственно, а на поверхности поперечного скола образца ― 120,0 и 100,0 нм соответственно, что статистически не отличалось от геометрических размеров каверн образца, полимеризованного при температуре +6…+25 °C. Изучение антибактериальной активности показало, что импрегнированный при +6…+25 °C в полиметилметакрилат стафилококковый бактериофаг ph20 утратил эффективный титр уже в течение первых шести суток с момента начала эксперимента, тогда как синегнойный бактериофаг ph57 сохранял эффективный титр как минимум в течение 13 сут. Заключение. В исследовании была подтверждена возможность импрегнации бактериофагов в полиметилметакрилат медицинского назначения с поддержанием эффективного титра бактериофага при его эмиссии во внешнюю среду, что открывает пути возможного применения такого способа доставки бактериофагов в клинической практике. Также сделаны предположения о вероятной подверженности некоторых бактериофагов агрессивным воздействиям со стороны химических компонентов «костного цемента» и/или продуктов реакции полимеризации, что требует строгого отбора пригодных для подобного способа доставки штаммов бактериофагов