Jurkat/A4 cells with multidrug resistance exhibit reduced sensitivity to quercetin

Background: While multidrug resistance of cancer cells is a well-known phenomenon, little is known on the cross resistance between cytotoxic chemotherapeutical agents and unrelated substances such as natural flavonoids. Aim: To compare the effects of cytotoxic drug, vepeside and natural flavonoid, quercetin in Jurkat cells and their multidrug-resistant subline Jurkat/A4, in particular to analyze the effector mechanisms of apoptosis and the profiles of several pro- and antiapoptotic proteins in these cells upon exposure to vepeside or quercetin. Methods: Apoptosis and poly (ADP-ribose) polymerase cleavage were assessed by flow cytometry. Expression of apoptosisrelated proteins was analyzed by Western blotting. Results: Jurkat/A4 cells are less sensitive to antiproliferative effects of quercetin as compared with the parental Jurkat cell line. While vepeside as well as quercetin initially induces apoptosis in both cell lines, the following survival of the exposed cells is essentially different. In resistant Jurkat/A4 cells, vepeside or quercetin treatment activates significantly less caspase-9 and -3 as compared with that in the parental cells. The expression of Bad and BNip1 proteins in Jurkat/A4 cells is lower than in the parental cell line. At the same time, XIAP and CAS levels in Jurkat/A4 cells increase. Upon apoptosis induction, XIAP and CAS levels in Jurkat cells decrease, this effect being negligible in resistant cells. Conclusion: Multidrug-resistant Jurkat/A4 cells exhibit reduced sensitivity to cytotoxic effects of quercetin. The expression profile of Jurkat/A4 cells is characterized by the increased levels of XIAP and CAS representing the endogenous inhibitors of apoptosis

The pseudo-spin symmetry in Zr and Sn isotopes from the proton drip line to the neutron drip line

Based on the Relativistic continuum Hartree-Bogoliubov (RCHB) theory, the pseudo-spin approximation in exotic nuclei is investigated in Zr and Sn isotopes from the proton drip line to the neutron drip line. The quality of the pseudo-spin approximation is shown to be connected with the competition between the centrifugal barrier (CB) and the pseudo-spin orbital potential (PSOP). The PSOP depends on the derivative of the difference between the scalar and vector potentials $dV/dr$. If $dV/dr = 0$, the pseudo-spin symmetry is exact. The pseudo-spin symmetry is found to be a good approximation for normal nuclei and to become much better for exotic nuclei with highly diffuse potential, which have $dV/dr \sim 0$. The energy splitting of the pseudo-spin partners is smaller for orbitals near the Fermi surface (even in the continuum) than the deeply bound orbitals. The lower components of the Dirac wave functions for the pseudo-spin partners are very similar and almost equal in magnitude.Comment: 22 pages, 9figure

Investigation of «cholesterol + model of biological membrane» complex by NMR spectroscopy

On the basis of the nuclear magnetic resonance (NMR) experiments it was established that molecules of sodium dodecyl sulfate can form micelles in dimethyl sulfoxide solution. The nuclear Overhauser effect between OH-group of cholesterol and "tail" groups of sodium dodecyl sulfate hydrophobic part was observed in 1D selective NOESY experiment. This observation corresponds to close spatial arrangement of these parts of different molecules and the presence of a complex between cholesterol and sodium dodecyl sulfate micelles

Investigation on stability of electrohydrodynamic shock waves

Well-posedness of a linear mixed problem on stability of electrohydrodynamic shock waves is investigated in the paper. Stability of shock waves for a hydrodynamic model of movement of a continuum with a volume electric charge is proved

Test of Nuclear Wave Functions for Pseudospin Symmetry

Using the fact that pseudospin is an approximate symmetry of the Dirac Hamiltonian with realistic scalar and vector mean fields, we derive the wave functions of the pseudospin partners of eigenstates of a realistic Dirac Hamiltonian and compare these wave functions with the wave functions of the Dirac eigenstates.Comment: 11 pages, 4 figures, minor changes in text and figures to conform with PRL requirement

Многослойные углеродные нанотрубки – компонент энергоемких суспензионных реактивных горючих

Objectives. The addition of high-density carbon materials to jet fuels can lead to a significant increase in the volumetric energy of the fuel combustion. The purpose of the current study was to thermodynamically analyze the possibility of obtaining model hydrocarbon fuels from toluene and T-1 using stacked-cup multiwall carbon nanotubes (MWCNTs). Methods. Bomb combustion calorimetry was used to define the combustion energy of the MWCNTs in the crystalline state. The temperature dependence of the MWCNTs’ heat capacity in the range 5–370 K and the fusion parameters were estimated using low-temperature adiabatic calorimetry. The physical density of MWCNTs was measured using the pycnometric method. The sedimentation stability of the mixtures of MWCNTs with liquids was determined using centrifugation at 7000 g. The calculations were carried out in MS Excel. Results. The energy and enthalpy of combustion of a technical sample of MWCNTs in the crystalline state were determined. Based on the smoothed heat capacity values, the standard thermodynamic functions (enthalpy, entropy, and Gibbs reduced energy) of MWCNTs in the crystalline state were obtained in a temperature range of 0–2000 K. The extrapolation of the MWCNTs’ heat capacity was carried out at a temperature of up to 2000 K using the heat capacity of crystalline graphite. It has been established that mixtures of MWCNTs with liquids containing more than 33 mass % of MWCNTs are stable during centrifugal sedimentation at 7000 g. For the toluene–MWCNTs and fuel T-1–MWCNTs model systems, the specific and volumetric combustion energies, the adiabatic combustion temperatures, and the conditional final maximum speed of the model rockets with fuel of various compositions were also calculated. Conclusions. The thermodynamic analysis showed that the addition of MWCNTs can significantly increase the volumetric energy intensity of traditional jet fuels, which can in turn improve the operational characteristics of drones and rockets. Цели. Добавление высокоплотных углеродных материалов в реактивные топлива может привести к значительному увеличению его объемной энергоемкости. Цель работы заключалась в проведении термодинамического анализа возможности получения модельных углеводородных топлив из толуола и Т-1 с многослойными углеродными нанотрубками (МУНТ). Методы. Свойства МУНТ были исследованы при помощи следующих методов: энергия сгорания в кристаллическом состоянии определена методом бомбовой калориметрии, температурная зависимость теплоемкости в интервале 5–370 K – методом адиабатической калориметрии, физическая плотность – пикнометрическим методом, седиментационная устойчивость смесей с жидкостями – центрифугированием при 7000 g. Расчеты проводились в программе MS Excel. Результаты. Определены энергия и энтальпия сгорания технического образца МУНТ в кристаллическом состоянии. На основании сглаженных значений теплоемкости получены стандартные термодинамические функции (энтальпия, энтропия и приведенная энергия Гиббса) МУНТ в кристаллическом состоянии в интервале 0–2000 K. Экстраполяция теплоемкости МУНТ до температуры 2000 K проведена с использованием теплоемкости кристаллического графита. Установлено, что смеси МУНТ с жидкостями, содержащими МУНТ более 33 масс. %, седиментационно устойчивы в центрифуге при 7000 g. Для модельных систем толуол–МУНТ, горючее Т-1–МУНТ вычислены массовые и объемные энергии сгорания, адиабатические температуры горения, условная конечная максимальная скорость модельных ракет с горючим различных составов. Выводы. Термодинамический анализ показал, что добавление МУНТ существенно повышает объемную энергоемкость традиционных реактивных топлив, что должно приводить к улучшению эксплуатационных характеристик летательных аппаратов.

Энергоемкость углеводородов в жидком и твердом состояниях

Objectives. The increased use of unmanned aerial vehicles necessitates the search for jet fuels based on hydrocarbon materials with high energy intensity and physical density. The purpose of the work was to analyze the influence of various factors on the mass energy intensity of hydrocarbons. This analysis is required to substantiate the algorithm for locating energy-intensive CnHm structures.Methods. Combustion energy was calculated using additive procedures. The calculations were performed using Microsoft Excel.Results. During the analysis of the mass energy intensity of CnHm hydrocarbons, the m/n ratio was discovered to be the decisive factor for achieving high values of the mass energy intensity of hydrocarbons. The energy intensity decreases when moving from alicyclic to cyclic hydrocarbons, and this decrease is not compensated by the production of strain energy. An additive scheme that allows the molar volume of hydrocarbons to be predicted with sufficient accuracy is proposed for calculating the volumetric enthalpies of combustion.Conclusions. According to the thermodynamic analysis, n-alkanes have the highest mass energy intensities. The technology for extracting n-alkanes from oil fractions is well developed, and a decrease in the hydrogen content in the fuel results in a decrease in the mass energy intensity. It appears improbable that the mass and volumetric energy intensities of hydrocarbons seem will reach their maximum values simultaneously. Hydrocarbons that have a high m/n value, 2, 3, 4, 5, 6-membered rings, and phenyl fragments may have relatively high mass and volumetric energy intensities at the same time.Цели. Расширение сфер использования беспилотных летательных аппаратов требует поиска реактивных топлив с высокой энергоемкостью и физической плотностью на основе углеводородных материалов. Цель работы заключалась в проведении анализа влияния различных факторов на массовую энергоемкость углеводородов, необходимого для обоснования алгоритма поиска энергоемких структур CnHm.Методы. Энергия сгорания рассчитывались с использованием аддитивных процедур. Расчеты проводились в программе MS Excel.Результаты. В ходе проведенного анализа массовой энергоемкости углеводородов CnHm было установлено, что решающим фактором для достижения высоких значений массовой энергоемкости углеводородов является отношение m/n. При переходе от алициклических углеводородов к циклическим энергоемкость снижается, и данное снижение не компенсируется возникающей энергией напряжения. Предложена аддитивная схема, позволяющая с достаточной точностью предсказать молярный объем углеводородов для расчета объемных энтальпий сгорания.Заключение. Термодинамический анализ показал, что максимальной массовой энергоемкостью обладают н-алканы, технология извлечения которых из нефтяных фракций хорошо отработана, уменьшение же содержания водорода в топливе приводит к снижению массовой энергоемкости. Одновременное достижение максимальных значений массовых и объемных энергоемкостей углеводородов представляется маловероятным. Возможно, одновременно более высокой массовой и объемной энергоемкостью будут обладать углеводороды с высоким значением m/n, содержащие 2, 3, 4, 5, 6-ти членные циклы и фенильные фрагменты

Distribution and abundance of western gray whales during a seismic survey near Sakhalin Island, Russia

Exxon Neftegas Limited, operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG), on behalf of the Sakhalin-1 consortium, conducted a 3-D seismic survey of the Odoptu license area during 17 August-September 2001. A portion of the primary known feeding area of the endangered western gray whale (Eschrichtius robustus) is located adjacent to the seismic block. The data presented here were collected as part of daily monitoring to determine if there was any measurable effect of the seismic survey on the distribution and abundance of western gray whales. Mitigation and monitoring program included aerial surveys conducted between 19 July and 19 November using the methodology outlined by the Southern California High Energy Seismic Survey team (HESS). These surveys provided documentation of the distribution, abundance and bottom feeding activity of western gray whales in relation to seismic survey sounds. From an operations perspective, the aerial surveys provided near real-time data on the location of whales in and outside the feeding area, and documented whether whales were displaced out of an area normally used as feeding habitat. The objectives of this study were to assess (a) temporal changes in the distribution and abundance of gray whales in relation to seismic survey, and (b) the influence of seismic survey, environmental factors, and other variables on the distribution and abundance of gray whales within their preferred feeding area adjacent to Piltun Bay. Multiple regression analysis revealed a limited redistribution of gray whales southward within the Piltun feeding area when the seismic survey was fully operational. A total of five environmental and other variables unrelated to seismic survey (date and proxies of depth, sea state and visibility) and one seismic survey-related variable (seg3d, i.e., received sound energy accumulated over 3 days) had statistically significant effects on the distribution and abundance of gray whales. The distribution of two to four gray whales observed on the surface (i.e., about five to ten whales in total) has likely been affected by the seismic survey. However, the total number of gray whales observed within the Piltun feeding area remained stable during the seismic survey