697 research outputs found
Индукция циркулирующих CD133+ стволовых лимфоцитов, коммитированных к ткани печени, у пациентов из листа ожидания трансплантации
Studies on the regenerative capabilities of tissues have shown that damaged liver can recover using hematopoietic stem cells (HSCs), which are able not only to replace cells in the target organ, but can also deliver trophic factors that support endogenous liver regeneration. There is practically no data on how organ-derived humoral signals involve such morphogenic/trophic cells in circulation. Objective: to investigate the role of non-invasive vibromechanical percutaneous action on the liver in cirrhosis by quantification of CD133+ lymphoid HSCs with specific hepatic marker alpha-fetoprotein (AFP) in patients awaiting liver transplantation. Materials and methods. In order to increase the number of AFP+ part of CD133+ stem lymphoid cells in the blood, the patient’s cirrhotic liver was mechanically activated by transcutaneous microvibration using electromagnetic vibrophones in contact with the skin. This generated mechanical impulses with a 10 μm amplitude and a smoothly varying frequency from 0.03 kHz to 18 kHz and back to within one cycle lasting 1 minute. The amount of AFP+ lymphocyte fraction in the total content of CD133+ HSCs in lymphocytes of potential recipients was monitored by flow cytometry before and during daily 15-minute sonication of the skin zone corresponding to the liver projection for three weeks with eight synphased vibraphones. Results. Sonication of the liver projection zone significantly increased the number of liver-specific CD133+ AFP+ lymphocytes by 2–3 times compared to the baseline values. Repeated similar sonication of the same site after a three-week break showed a statistically insignificant increase from the initial level. With a similar effect on the spinal projection in the control group of waitlisted patients with cirrhosis, there was no increase in CD133+ AFP+ lymphocytes. Conclusion. Mechanical stress prompts the organ to secrete specific humoral signals that provoke the bone marrow to produce additional lymphoid stem cells committed to the liver and recruit them into circulation.Исследования регенераторных возможностей тканей доказали восстановление поврежденной печени с помощью стволовых гемопоэтических клеток (СГК), которые способны не только замещать клетки в органе-мишени, но также могут доставлять трофические факторы, поддерживающие эндогенную регенерацию печени. Данных о том, как органопроизводные гуморальные сигналы вовлекают такие морфогенные/трофические клетки в циркуляцию, практически нет. Цель: исследовать роль неинвазивного вибро-механического чрескожного воздействия на печень при циррозе с помощью количественного учета в крови фракции CD133+ гемопоэтических стволовых клеток лимфоидного ряда со специфическим печеночным маркером альфа-фетопротеином (АФП) у больных, ожидающих трансплантацию печени. Методы. Для повышения в крови числа АФП-позитивной части CD133+ стволовых лимфоидных клеток механически активировали цирротическую печень пациента путем чрескожной микровибрации с помощью контактирующих с кожей электромагнитных виброфонов, генерирующих механические импульсы амплитудой 10 мкм и плавно меняющейся частотой от 0,03 Гц до 18 кГц и обратно в течение одного цикла продолжительностью 1 минута. Количество АФП-положительной фракции лимфоцитов в общем содержании CD133+ СГК в лимфоцитах потенциальных реципиентов контролировали методом проточной цитометрии до и во время ежедневного 15-минутного сонирования кожной зоны, соответствующей проекции печени, в течение трех недель, восемью синфазированными виброфонами. Результаты. Звуковое воздействие на зону проекции печени достоверно увеличило количество печеночно-специфических АФП-позитивных CD133+ лимфоцитов крови в 2–3 раза по сравнению с базовыми значениями. Повторное аналогичное сонирование той же зоны после трехнедельного перерыва показало статистически не значимое превышение исходного уровня. При аналогичном воздействии на проекцию позвоночника в контрольной группе больных циррозом печени из листа ожидания феномен увеличения альфа-фетопротеин-позитивных CD133+ лимфоцитов не возникал. Вывод. Механический стресс побуждает орган секретировать специфические гуморальные сигналы, провоцирующие костный мозг производить дополнительные коммитированные к печени стволовые лимфоидные клетки и рекрутировать их в циркуляцию
Protons in near earth orbit
The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured
by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at
an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is
parameterized by a power law. Below the geomagnetic cutoff a substantial second
spectrum was observed concentrated at equatorial latitudes with a flux ~ 70
m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated
trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure
A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01
The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics
experiment that will study cosmic rays in the to range and will be installed on the International Space Station
(ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the
space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected
cosmic ray triggers. Part of the \emph{Mir} space station was within the
AMS-01 field of view during the four day \emph{Mir} docking phase of this
flight. We have reconstructed an image of this part of the \emph{Mir} space
station using secondary and emissions from primary cosmic rays
interacting with \emph{Mir}. This is the first time this reconstruction was
performed in AMS-01, and it is important for understanding potential
backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor
stylistic and grammer change
ISOTOPIC COMPOSITION OF LIGHT NUCLEI IN COSMIC RAYS: RESULTS FROM AMS-01
The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios [superscript 2]H/[superscript 4]He, [superscript 3]He/[superscript 4]He, [superscript 6]Li/[superscript 7]Li, [superscript 7]Be/([superscript 9]Be+[superscript 10]Be), and [superscript 10]B/[superscript 11]B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.United States. Dept. of EnergyMassachusetts Institute of Technolog
Search for antihelium in cosmic rays
The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle
Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320
and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity
range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper
limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure
Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01
The variety of isotopes in cosmic rays allows us to study different aspects
of the processes that cosmic rays undergo between the time they are produced
and the time of their arrival in the heliosphere. In this paper we present
measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be)
and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The
measurements are based on the data collected by the Alpha Magnetic
Spectrometer, AMS-01, during the STS-91 flight in 1998 June.Comment: To appear in ApJ. 12 pages, 11 figures, 6 table
Study of Spin and Decay-Plane Correlations of W Bosons in the e+e- -> W+W- Process at LEP
Data collected at LEP at centre-of-mass energies \sqrt(s) = 189 - 209 GeV are
used to study correlations of the spin of W bosons using e+e- -> W+W- -> lnqq~
events. Spin correlations are favoured by data, and found to agree with the
Standard Model predictions. In addition, correlations between the W-boson decay
planes are studied in e+e- -> W+W- -> lnqq~ and e+e- -> W+W- -> qq~qq~ events.
Decay-plane correlations, consistent with zero and with the Standard Model
predictions, are measured
Ultrarelativistic sources in nonlinear electrodynamics
The fields of rapidly moving sources are studied within nonlinear
electrodynamics by boosting the fields of sources at rest. As a consequence of
the ultrarelativistic limit the delta-like electromagnetic shock waves are
found. The character of the field within the shock depends on the theory of
nonlinear electrodynamics considered. In particular, we obtain the field of an
ultrarelativistic charge in the Born-Infeld theory.Comment: 10 pages, 3 figure
Measurement of the Cross Section for Open-Beauty Production in Photon-Photon Collisions at LEP
The cross section for open-beauty production in photon-photon collisions is
measured using the whole high-energy and high-luminosity data sample collected
by the L3 detector at LEP. This corresponds to 627/pb of integrated luminosity
for electron-positron centre-of-mass energies from 189GeV to 209GeV. Events
containing b quarks are identified through their semi-leptonic decay into
electrons or muons. The e+e- -> e+e-b b~X cross section is measured within our
fiducial volume and then extrapolated to the full phase space. These results
are found to be in significant excess with respect to Monte Carlo predictions
and next-to-leading order QCD calculations
Search for Branons at LEP
We search, in the context of extra-dimension scenarios, for the possible
existence of brane fluctuations, called branons. Events with a single photon or
a single Z-boson and missing energy and momentum collected with the L3 detector
in e^+ e^- collisions at centre-of-mass energies sqrt{s}=189-209$ GeV are
analysed. No excess over the Standard Model expectations is found and a lower
limit at 95% confidence level of 103 GeV is derived for the mass of branons,
for a scenario with small brane tensions. Alternatively, under the assumption
of a light branon, brane tensions below 180 GeV are excluded
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