Study of distortion effects and clustering of isotopic impurities in solid molecular para-hydrogen by Shadow Wave Functions

We employed a fully optimized Shadow Wave Function (SWF) in combination with Variational Monte Carlo techniques to investigate the properties of HD molecules and molecular ortho-deuterium (o-D_2) in bulk solid para-hydrogen (p-H_2). Calculations were performed for different concentrations of impurities ranging from about 1% to 25% at the equilibrium density for the para-hydrogen crystal. By computing the excess energy both for clustered and isolated impurities we tried to determine a limit for the solubility of HD and o-D_2 in p-H_2.Comment: 4 pages, 4 figure

Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

We have concurrently measured the specific heat, the thermal conductivity, and the longitudinal and transverse sound velocities at low temperature of glasses from different isomers of butanol (n-butanol, sec-butanol and isobutanol), as well as the low-temperature specific heat for the crystals of n-butanol, isobutanol and tert-butanol. Whereas the elastic constants both for crystals and glasses are found to be almost independent of the position of the hydrogen bonds, the thermal properties at low temperatures of these glasses at a few kelvin (around the boson peak in the reduced specific heat or around the plateau in the thermal conductivity) are found to vary strongly. Our experiments clearly contradict other works or models claiming a Debye scaling of the boson peak, and hence of the excess low-temperature specific heat of glasses. Data analysis based upon the soft-potential model and its extensions allows us to estimate the Ioffe-Regel limit in these and other alcohol glasses, finding a correlation with the boson-peak position in agreement with that previously reported by other groupsWe acknowledge financial support by the Spanish Ministry of Science within program CONSOLIDER Nanociencia Molecular CSD2007-00010 and by the Comunidad de Madrid through the project NANOBIOMAGNET S2009/MAT-1726

Phonon scattering in ortho-para hydrogen solid solutions (role of configurational relaxation)

The experimental data on the thermal conductivity of ortho-parahydrogen solutions are analyzed on the basis of a relaxation-time model taking account of configurational relaxation of the ortho subsystem. The influence of configurational relaxation on the thermal conductivity is analyzed using resonance scattering of phonons by pair clusters of orthomolecules taking account of their rotational spectrum.Comment: 7 pages, 4 figure

Low-temperature properties of monoalcohol glasses and crystals

We review and jointly discuss both earlier and recent experiments conducted by us on simple aliphatic glass-forming monoalcohols at low temperatures, including specific heat, thermal conductivity, Brillouin scattering and x-ray diffraction experiments. The family of simple monoalcohols constitutes an interesting model system to explore different relevant issues concerning molecular glass-forming liquids, low-temperature universal proper-ties of glasses, and even the glass transition phenomenon itself. More specifically, we discuss the role played by the molecular aspect ratio in vitrification/crystallization kinetics, the reported appearance of particular cases of polymorphism (in ethanol) and polyamorphism (in butanol), and especially the influence of position isomerism and the location of the hydrogen bond on the lattice dynamics and hence on the low-temperature universal prop-erties of glasses

Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom

The thermal conductivity, specific heat, and specific volume of the orientational glass former 1,1,2-trichloro-1,2,2-trifluoroethane (CCl2F-CClF2, F-113) have been measured under equilibrium pressure within the low-temperature range, showing thermodynamic anomalies at ca. 120, 72, and 20 K. The results are discussed together with those pertaining to the structurally related 1,1,2,2-tetrachloro-1,2-difluoroethane (CCl2F-CCl2F, F-112), which also shows anomalies at 130, 90, and 60 K. The rich phase behavior of these compounds can be accounted for by the interplay between several of their degrees of freedom. The arrest of the degrees of freedom corresponding to the internal molecular rotation, responsible for the existence of two energetically distinct isomers, and the overall molecular orientation, source of the characteristic orientational disorder of plastic phases, can explain the anomalies at higher and intermediate temperatures, respectively. The soft-potential model has been used as the framework to describe the thermal properties at low temperatures. We show that the low-temperature anomaly of the compounds corresponds to a secondary relaxation, which can be associated with the appearance of Umklapp processes, i.e., anharmonic phonon-phonon scattering, that dominate thermal transport in that temperature rangeThis work was financially supported in part by the Spanish Ministry of Science and Innovation (Grant Nos. FIS2014-54734-P, FIS2011-23488, and MAT2014-57866- REDT), by the Catalan Government (Grant No. 2014SGR- 0581) and by the Comunidad de Madrid through program NANOFRONTMAG-CM (No. S2013/MIT-2850), as well as by the joint NAS Ukraine and Russian Foundation for Basic Research project “Metastable states of simple condensed systems” (Agreement No. N 7/-2013

Лимфорея в послеоперационном периоде у онкохирургических больных

Purpose: to evaluate the influence of postoperative lymphatic leakage volume and duration on homokinesis and incidence of postoperative complications in oncosurgury patients underwent different operative interventions.Material and methods. The results of treatment of 310 patients subjected to standard elective surgical intervention for a malignant pathology of different organs with regional lymph node dissection were evaluated. The selection criterion was prolonged (more than 7 days) and prominent (over 50 ml a day) lymphatic leakage during the postoperative period. The fluid discharged during the postoperative period was identified as a lymph by cytology. The diagnosis of a malignant pathology was verified in all patients after histological examination and patients were distributed according to established diagnosis.Results. The duration of lymphatic leakage including the outpatient treatment stage varied from 9 days to 1 year and 2 months depending on the type of surgery. The longest lymphatic leakage occurred in 2 patients after radical mastectomy. During the 1st week of observation in patients with daily lymph losses up to 100 ml, no changes in the blood composition were noted. Prolonged lymphatic leakage (1–2 weeks after operation) in a volume over 100 ml a day resulted in reduced protein content in blood plasma, severe lymphocytopenia, increased platelet count. During the postoperative period, complications were detected in 31 patients; at that, during the 1st week of observation, 27 patients experienced initial lymphatic leakage over 100 ml a day. Analysis of fatal outcomes (7 patients) showed that in all patients the lymphatic leakage exceeded 150 ml a day and lasted 1 to 2 weeks. The longest inpatient time was typical for patients after Wertheim's hysterectomy and cystectomy, whereas the longest outpatient treatment was experienced by patients after radical mastectomy and inguinofemoral lymph node dissection.Conclusion. In case of lymphatic leakage over 100 ml a day in oncosurgury patients, it was necessary to make up protein losses and after 7 days of persistent lymphatic leakage it became necessary to consider use of active surgical tactics aimed at liquidation of lymph losses.Цель: определить влияние объема и длительности послеоперационной лимфореи на гомеокинез и частоту развития послеоперационных осложнений у онкологических больных при различных хирургических вмешательствах.Материал и методы. Оценили результаты лечения 310 пациентов, которым проводили стандартное плановое хирургическое вмешательство по поводу злокачественной патологии различных органов с регионарной лимфодиссекцией. Критерием отбора была длительная (более 7 дней) и выраженная (более 50 мл в сутки) лимфорея в послеоперационном периоде. Отделяемую в послеоперационном периоде жидкость идентифицировали как лимфу цитологически. Диагноз злокачественной патологии верифицировали у всех пациентов после гистологического исследования и больных распределили по нозологическим формам.Результаты. Продолжительность лимфореи, включая амбулаторный этап лечения, в зависимости от вида операции составила от 9 дней до 1 года 2 месяцев. Максимально продолжительная лимфорея имелась у 2-х пациенток после радикальной мастэктомии. В течение 1-й недели наблюдения пациентов с ежедневными лимфопотерями до 100 мл изменений в составе крови не отметили. Продолжительная лимфорея (1–2 недели после операции) объемом более 100 мл в сутки приводила к снижению содержания белка в плазме крови, выраженной лимфоцитопении, увеличению количества тромбоцитов. Осложнения в послеоперационном периоде выявили у 31 пациента, при этом у 27 больных в течение 1-й недели наблюдения исходная лимфорея была более 100 мл в сутки. Анализ смертельных исходов (7 человек) показал, что у всех пациентов лимфорея превышала 150 мл в сутки, длилась от 1 до 2 недель. Наиболее продолжительным пребыванием в стационаре характеризовались пациенты после операции Вертгейма и цистэктомии, амбулаторно дольше всего лечились пациенты после радикальных мастэктомий и пахово-бедренных лимфодиссекций.Заключение. При лимфорее более 100 мл в сутки у пациентов онкохирургического профиля необходимо восполнение белковых потерь, а после 7 суток, при некупируемой лимфорее в таких объемах, возникает необходимость в постановке вопроса о применении активной хирургической тактики, направленной на ликвидацию лимфопотерь