Search

The goal of this paper is to review the pharmacological profile of betahistine and evidence for using it in the treatment of common vestibular disorders. Betahistine is a weak agonist for histamine H1 receptors and strong antagonist for histamine H3 receptors. It demonstrates the maximum benefit in different types of peripheral vertigo, especially in Meniere's disease. The best results in decreasing intensity of vertigo, frequency of attacks and stimulation of vestibular compensation were obtained in daily dose 48 mg during 3 months. In benign paroxysmal positional vertigo betahistine is used to treat residual dizziness after successful treatment of otolithiasis and to reduce the severity of vertigo during repositioning maneuvers. In vestibular neuritis betahistine stimulates central compensation during vestibular rehabilitation. A new once-daily drug formulation of modified-release betahistine is non-inferior to traditional and has a comparable safety profile, and could improve patient adherence. The implication of betahistine in the treatment of central vestibular disorders is under-researched. The efficacy of betahistine in increasing of vestibular compensation in post-stroke central vestibular disorders, persistent postural-perceptual dizziness and its role in vestibular migraine need further investigation.Данной работы — обзор современных представлений о фармакологических свойствах бетагистина, его месте в лечении наиболее распространенных вестибулярных заболеваний. Бетагистин является частичным агонистом гистаминовых H1-рецепторов и сильным антагонистом гистаминовых H3-рецепторов. Наибольшая эффективность этого препарата продемонстрирована при лечении периферических вестибулярных расстройств, особенно болезни Меньера. Наилучшие результаты лечения в виде уменьшения интенсивности головокружения, снижения частоты приступов, стимуляции вестибулярной компенсации получены при приеме суточной дозы 48 мг в течение 3 мес. При доброкачественном пароксизмальном позиционном головокружении бетагистин используется для лечения резидуального головокружения после купирования отолитиаза и уменьшения выраженности головокружения при выполнении репозиционных упражнений. При вестибулярном нейроните бетагистин назначается для стимуляции центральной компенсации в процессе вестибулярной реабилитации. Повышению приверженности пациентов лечению может способствовать применение новой лекарственной формы бетагистина модифицированного высвобождения, назначаемого 1 раз в сутки, обладающего не меньшей эффективностью по сравнению с традиционной формой и сходным профилем безопасности. Роль бетагистина в лечении центральных вестибулярных расстройств недостаточно изучена. Способность бетагистина ускорять вестибулярную компенсацию при постинсультных центральных вестибулярных расстройствах, персистирующем постуральном перцептивном головокружении, а также его роль при вестибулярной мигрени должны быть изучены в дальнейших исследованиях.

The paper addresses issues related to selection of sand control systems applied when producing heavy oil from unconsolidated rocks. A sharp productivity reduction was noticed during the operation of wells with filters. A methodology accounting for subsurface features has been developed for laboratory testing of well-completion systems to reduce uncertainties. Damage related to undesirable drop in flow rate was analyzed. As a result, corrections were promptly introduced to the size of filters used in well completions, which led to increased productivity of newly commissioned wells.

The results of experimental studies of a passive system for removing heat through steam generators which were performed on a large-scale (1/110) stand at the Scientific-Industrial Association for Research and Design of Power-Generation Equipment (NPO TsKTI, St. Petersburg) are presented. The experiments show that the system performs reliably and effectively as designed. The experimental data were used to verify the thermohydraulic codes KORSAR and SOKRAT, which are used to model the thermohydraulic processes in the system at the Leningradskaya nuclear power plant.

The aim of the study was assessment of gait parameters with a laser range finder use in patients with cerebellar ataxia syndrome. There are reliable differences in the relative stride length and stride variability coefficient for the patients with ataxia in comparison with the healthy middle aged people was found.

Researchers performing radiation testing on electronic components often rely on semi-empirical prediction codes for determining the linear energy transfer (LET) (or electronic stopping force) of ions, without paying much attention to their reliability. However, it is seen that estimations calculated with different codes can have over 10% discrepancies, especially in the case of heavy ions with higher LET (e.g., xenon). As a consequence of the modern component fabrication techniques this has become an important issue when studying the radiation durability of electronics. In order to clarify this inconsistency, LET measurements for 131Xe and 82Kr in silicon have been undertaken and obtained results are presented, discussed and compared with earlier predicted data.

Energy loss of 40Ar ions in Au has been measured using two methods: TOF-E and TOF–TOF. The two methods are compared and discussed. The final results cover energy range 2–445 MeV (0.05–11 MeV/u) and give satisfactory agreement with SRIM 2003 predictions. Statistical error of the data is at the level of 1–2%.

A transmission experiment utilizing thin foil targets has been conducted in order to establish the stopping powers of the cobalt-base alloy, havar, for 0.6-5.9 MeV protons and 2.6-24 MeV alpha particles. The basic technique of the novel experimental method used was to record both the projectile energy and the time of flight while alternating measurements with and without the target in place. The uncertainties of the proton and alpha particle data sets ranged from 1.4 to 2.3% and 1.1 to 1.5%, respectively. Modified Bethe-Bloch theory was applied to the measurements in order to ascertain values of the target mean excitation energy (I) and Barkas-effect parameter (b) for each projectile. The extracted values were I = 304.3 ± 2.4 eV and b = 1.37 ± 0.04 for the case of protons, and I = 306.3 ± 2.3 eV and b = 1.47 ± 0.03 for the case of alpha particles. The I-values are somewhat higher than the additivity-based expectation of 295.7 eV, whereas the b-values are clearly consistent with the expected range of 1.4 ± 0.1. The parameter values extracted from the measurements are appraised for compatibility with recently observed trends in values of I and of b with increasing projectile atomic number.

The stopping powers of polycarbonate for protons of energy 0.6–5.9 MeV and α particles of energy 2.0–24.0 MeV have been measured in a transmission experiment employing thin-foil targets. The essence of the novel experimental method employed in the present measurements is to record both projectile energy and time of flight while constantly alternating measurements with and without the target foil in place. The accuracies of the proton data and α-particle data range from 2.0% to 3.0% and 2.2% to 2.7%, respectively. All of the resulting measurements were analyzed in terms of modified Bethe–Bloch theory in order to extract values of the target mean excitation energy (I) and Barkas-effect parameter (b). The composite results for the two projectiles are that I=71.52 eV and b=1.13, the former value lying about one standard deviation below the additivity value and the latter value lying about one standard deviation below the expected value of 1.4±0.1. Previous measurements of the stopping power of polycarbonate f...

Comparing time of flight (TOF) values for α particles and fission fragments measured at different distances between the start- and stop detector we have obtained 60 ps as the upper limit for the TOF error resulting from the assumption of equal and linear time calibrations for both types of particles. While the 60 ps limit relates only to the specific spectrometer, the problem and the suggested verification technique are of general interest.

A new approach to energy loss measurements is proposed. In the same experiment electronic stopping force (power) in gold, nickel, carbon, polycarbonate and Havar for 40 Ar, 28 Si, 16 O, 4 He and 1 H ions in the energy range 0.12–11 MeV/u has been measured. In this paper we give the full results for gold, nickel, and carbon and for 40 Ar, 16 O, 4 He and 1 H ions. Good agreement of the measured stopping force values for light ions with literature data is interpreted as the positive test of the experimental technique. The same technique used with heavy ions yields agreement with the published data only for energies above 1 MeV/u. At lower energies we observe progressively increasing discrepancy. This discrepancy is removed completely as soon as we neglect pulse height defect compensation. This observation makes us believe that the majority of the published results as well as semi-empirical calculations based on them (like the popular SRIM) may be in error at low ion energies. Procedures to evaluate foil quality and to determine pulse height defect for charged ions in semiconductor detectors are given. Our improved MCP-based time pick-off detector is described in detail.

A new procedure to extract simultaneously continuous stopping power curves for several ions and several absorbers over a wide energy range and with statistical errors reduced to negligible level is presented. The method combines our novel time-of-flight based method with the capability of our K130 cyclotron and ECR ion-source to produce the so-called ion cocktails. The potential of the method is demonstrated with a 6.0 MeV/u cocktail consisting of 16O4+, 28Si7+ and 40Ar10+ ions. The stopping power in polycarbonate in the energy range of 0.35–5 MeV/u has been determined with absolute uncertainty of less than 2.3% and with relative below 0.2%. The results are compared with literature data and with SRIM2000 parameterisation including cores and bonds corrections.

WereportonresultsofefficiencytestsforMIPsandtimingresolutionstudiesobtainedwithdifferentlayoutsofmicro-channelplate(MCP)detectorprototypesatCERNPStestbeams.ThedetectoriscomposedofanMCPstackand multipad readout anodes integrated with a passive isochronal summator. Several types of setups were tested,includingMCPswithdifferentgain.Also,averyfirsttestoftheMicroSpherePlatesdetectorwasperformed.TheperformanceoffastelectronicsincludingDoubleThresholdDiscriminatorsandafastmultiplicitydiscriminatorforshort2nssignalswasstudied.Currently,thebestexperimentalresultsforMCPdetectorsshow75pstimingresolutionobtainedat75%efficiencyfortheregistrationofasinglemuon.Weexpectfurtherenhancements,mostlythroughimprovementsinthefastelectronics.r 2002ElsevierScienceB.V.Allrightsreserved. 1. IntroductionA Micro-Channel Plate (MCP) disk detectorsystem with integrated isochronal signal readoutandprecisetimingcapabilitiesisconsideredasoneof the options for the ALICE pre-trigger T0/centralitydetector.MCPsareawell-knowndevicefor the registration of charged particles due totheir excellent timing properties (20–50ps), highinternalgain(10

A new method has been developed for obtaining continuous stopping power curves in transmission geometry. In the method both the incident energy of the particle and its energy after passing through the sample foil are extracted directly from the semiconductor detector. Full range of energies is measured simultaneously eliminating step-by-step measurements and providing continuous data. A time-of-flight (TOF) spectrometer provides unambiguous matching of relevant particle groups from the run with and without absorber. Suitable energy distribution of incident particles was achieved by choosing the right thickness and tilting angle of a scattering foil. The method is very fast and reliable. Sample results for stopping power values for 40 Ar in Au, Ni, and polycarbonate are presented and compared with SRIM-2000 calculations. It is proposed to adopt a suitable standard for specific energy loss measurements to avoid possible discrepancies in energy calibration. For instance, Au or C would be good reference materials and all the new high precision data should be quoted not only in absolute values but also relative to the standard material that was measured with the same set-up. Our new method provides sufficient accuracy and speed to make such an approach feasible.

In the present paper we describe an experiment performed on the reaction 238U + 4He (40 MeV) using a two‐arm TOF‐E (time‐of‐flight vs. energy) spectrometer with micro‐ channel plate detectors and mosaics of PIN diodes. This experiment has aimed at searching for fine structures in the total kinetic energy vs. fragment mass (TKE ‐ M) distributions of binary events, and disclosing rare ternary decay modes others than already known from ternary fission. Details of the procedures of data handling are briefly described as well.

Fast timing and trigger detector T0 for the ALICE experiment at CERN LHC is described. Performance of T0 prototype measured with a mixture of 6 GeV/c negative pions and kaons is given. The best time resolution (28 ps r.m.s.) was reached with radiator diameter matching that of the photo cathode. The results for all the tested radiator sizes are considerably better than 50 ps - the baseline requirement for ALICE experiment.

Flerov Laboratory of Nuclear Reactions, JINR, 141 980 Dubna, Russia 'Universite Libre de Bruxelles, Bruxelles, Belgique 'Institut de Recherches Subatomiques, CNRS-IN2P3, Strasbourg, France 'Deparment of Physics, University of Jwiiskyla, FIN-40351, Jyvaskyla, Finland V. G. Khlopin Radium Institute, St.-Petersburg 194021, Russia 'Texas A&M lJniversi& Cyclotron Institute, College Station, Texas, 77843-3366, USA

Fig. 1. Relation of the rheochor Rch to the pa rachor Pch for boil ing organic liquids. The open c i rc les are saturated aliphatic hydrocarbons, the open t r iangles are aromat ic hydrocarbons, the open squares are n i t r i les , the black c i rc les are chlorine and bromine derivat ives of alkanes, the c ro s se s are saturated, monoatomic alcohols, the inverted black t r iangles are simple ethers , the inverted open t r iangles are aldehydes and ketones, the black squares are nitrocompounds, the pluses are amines, and the black t r iangles are monobasic acids of a se r ies of fats. Fig. 2. Corre la t ion of heat t r ans fe r coefficients for the boiling of water and organic liquids in ver t ical copper boi lers . The open t r iangles are for water, the open c i rc les a r e for alkanes, the black c i rc les are for monoatomic saturated alcohols, and the c ros se s are for mixtures of a lcohols.

The method of preparing monolithic linings consists of preparing the castable mixtures, casting the monolithic lining, and subsequent heat treatment. During development of the method and wide production testing of it, the siliceous filler was First Ural crystalline quartzite containing not less than 97% silica with a refractoriness of not less than 1730~ (Technical Specification 14-8-99-74) of the following composition: 5% over 3 mm fraction, 15-25% 2-3 mm fraction, 40-45% under 0.5 mm fraction including 25-30% under 0.i mm fraction.