465 research outputs found
DEGENERATIVE SPINE INJURY ASSOCIATED WITH BACK PAIN: MORPHOGENETIC ASPECTS
Degeneration of the intervertebral disk (IVD) is a pathological process resulting from an interplay between genetic and environmental factors causing structural and functional damage of the IVD and neighboring structures. It is the first stage of degenerative cascade in the vertebral motion segment. Initiation and progression of IVD degenerative processes traditionally involves several factors: inadequate mechanical load, decreased diffusion of nutrients through the arch laminae, and genetic factors playing a significant role in the development of degenerative changes. Three categories of candidate genes whose coding variants are associated with different forms of degenerative changes in the IVD are identified, a conceptual model of genetic interactions in degenerative disease of the disk is developed. The study of the role of structural changes in back pain genesis, evaluation of risk factors allow to optimize the tactics of patient care and find new therapeutic solutions preventing disease progression
Комплексные болевые синдромы в практике врача-интерниста: диагностика, лечение
The paper presents the basic criteria for diagnosing complex regional pain syndromes, the most important links of their pathogenesis and the specific features of their clinical picture. Much attention is given to their treatment options, including these with nonsteroidal anti-inflammatory drugs.Представлены основные критерии диагностики, важнейшие звенья патогенеза и особенности клинической картины комплексных региональных болевых синдромов. Большое внимание уделено способам лечения патологии, в том числе и нестероидными противовоспалительными препаратами
Efficiency Estimation of the Single- and Multicomponent Anti-hydrate Reagents
Different types of technological and technical problems in the oil, gas and chemical industries are connected with the hydrate formation process and with the using of anti-hydrate chemicals. That is why, it is necessary to estimate thermobaric ranges within which reagents does not let hydrate to grow or is their dissociation. Also, to estimate anti-hydrate influence we need to determine the chemicals’ anti-hydrate efficiency and chose the best one.
They make the reagents consisting of several chemical components depending on the purpose of their application – for prevention of formation and (or) elimination of hydrates. It demands calculations of the optimum concentration and expenses and also the intensity (speed) of hydrates dissociation causing with the reagents.
The analytical method of the anti-hydrate chemical reagents efficiency determination containing one or several components from different classes of chemical compounds – alcohols, salts, acids, compounds of nitrogen and oxygen – is presented in this paper. With its help it is possible to define decrease in temperature of hydrate formation from reagents influence, to count key parameters of reagents anti-hydrate efficiency depending on component compositions of hydrate gas and a phase condition of a hydrate-gas system, to select types of chemical components and their quantity in multicomponent reagents, i.e., to make new compounds. The method can be used for express assessment of anti-hydrate chemical reagents efficiency on criteria sign for practical application in oil, gas and processing industry
HIP AND BUTTOCKS PAIN SYNDROME — LOOK OF THE INTERNIST
Differential approach to the diagnosis of diseases associated with pain in the hips and buttocks is presented in this lecture
The Tully-Fisher Relation and H_not
The use of the Tully-Fisher (TF) relation for the determination of the Hubble
Constant relies on the availability of an adequate template TF relation and of
reliable primary distances. Here we use a TF template relation with the best
available kinematical zero-point, obtained from a sample of 24 clusters of
galaxies extending to cz ~ 9,000 km/s, and the most recent set of Cepheid
distances for galaxies fit for TF use. The combination of these two ingredients
yields H_not = 69+/-5 km/(s Mpc). The approach is significantly more accurate
than the more common application with single cluster (e.g. Virgo, Coma)
samples.Comment: 10 pages, including 2 figures and 1 table; uses AAS LaTex. Submitted
to ApJ Letter
The Molecular ISM of Dwarf Galaxies on Kiloparsec Scales: A New Survey for CO in Northern, IRAS-detected Dwarf Galaxies
We present a new survey for CO in dwarf galaxies using the Kitt Peak 12m
telescope. We observed the central regions of 121 northern dwarfs with IRAS
detections and no known CO emission. We detect CO in 28 of these galaxies and
marginally detect another 16, increasing by about 50% the number of such
galaxies known to have significant CO emission. The galaxies we detect are
comparable in mass to the LMC, although somewhat brighter in CO and fainter in
the FIR. Within dwarfs, we find that the CO luminosity, L_CO, is most strongly
correlated with the K-band and the far infrared luminosities. There are also
strong correlations with the radio continuum and B-band luminosities, and
linear diameter. We suggest that L_CO and L_K correlate well because the
stellar component of a galaxy dominates the midplane gravitational field and
thus sets the pressure of the atomic gas, which controls the formation of H_2
from HI. We compare our sample with more massive galaxies and find that dwarfs
and large galaxies obey the same relationship between CO and the 1.4 GHz radio
continuum (RC) surface brightness. This relationship is well described by a
Schmidt Law with Sigma_RC proportional to Sigma_CO^1.3. Therefore, dwarf
galaxies and large spirals exhibit the same relationship between molecular gas
and star formation rate (SFR). We find that this result is robust to moderate
changes in the RC-to-SFR and CO-to-H_2 conversion factors. Our data appear to
be inconsistent with large (order of magnitude) variations in the CO-to-H_2
conversion factor in the star forming molecular gas. [abridged]Comment: 28 pages, 14 figures, 5 tables, ApJ accepte
HI power spectrum of the spiral galaxy NGC628
We have measured the HI power spectrum of the nearly face-on spiral galaxy
NGC628 (M74) using a visibility based estimator. The power spectrum is well
fitted by a power law , with over the
length scale . The slope is found to be
independent of the width of the velocity channel. This value of the slope is a
little more than one in excess of what has been seen at considerably smaller
length scales in the Milky-Way, Small Magellanic Cloud (LMC), Large Magellanic
Cloud (SMC) and the dwarf galaxy DDO210. We interpret this difference as
indicating a transition from three dimensional turbulence at small scales to
two dimensional turbulence in the plane of the galaxy's disk at length scales
larger than galaxy's HI scale height.
The slope measured here is similar to that found at large scales in the LMC.
Our analysis also places an upper limit to the galaxy's scale height at $800\
{\rm pc}$ .Comment: 4 Pages, 2 Figures, 1 Table. Accepted for Publication in MNRAS
LETTER
Chronic Heart Failure and Pulmonary Hypertension: Difficulties in Assessment of Prognosis and Potential Solutions
Pulmonary hypertension and right heart dysfunction often complicate the course of chronic heart failure. At the same time, the addition of these pathological conditions significantly increases the frequency of hospitalizations and worsens survival prognosis. That is why the assessment of the unfavorable outcome’s risk in the group of such patients is extremely important. This problem draws an interest for a more detailed study, considering the fact that the most convenient, accessible and minimally invasive prognosis marker has still being searched for nowadays. In this review article, which is based on the analysis of literature over the past 20 years dedicated to the problem of pulmonary hypertension and chronic heart failure, right ventricular-arterial coupling, has been considered as a relatively new parameter and as an example of one of these prognostic markers. This parameter can be assessed by echocardiography examination and our article describes several options of calculating it, including one of the most popular and valuable ratio of tricuspidal anular plane systolic excursion to the systolic pulmonary artery pressure (TAPSE/sPAP)
Discovery of Recent Star Formation in the Extreme Outer Regions of Disk Galaxies
We present deep Halpha images of three nearby late-type spiral galaxies
(NGC628, NGC1058 and NGC6946), which reveal the presence of HII regions out to,
and beyond, two optical radii (defined by the 25th B-band isophote). The
outermost HII regions appear small, faint and isolated, compared to their inner
disk counterparts, and are distributed in organized spiral arm structures,
likely associated with underlying HI arms and faint stellar arms. The
relationship between the azimuthally--averaged Halpha surface brightness
(proportional to star formation rate per unit area) and the total gas surface
density is observed to steepen considerably at low gas surface densities. We
find that this effect is largely driven by a sharp decrease in the covering
factor of star formation at large radii, and not by changes in the rate at
which stars form locally. An azimuthally--averaged analysis of the
gravitational stability of the disk of NGC6946 reveals that while the existence
of star formation in the extreme outer disk is consistent with the Toomre-Q
instability model, the low rates observed are only compatible with the model
when a constant gaseous velocity dispersion is assumed. We suggest that
observed behaviour could also be explained by a model in which the star
formation rate has an intrinsic dependence on the azimuthally-averaged gas
volume density, which decreases rapidly in the outer disk due to the vertical
flaring of the gas layer.Comment: 10 pages, 2 embedded postscript files, 3 jpeg images; accepted for
publication in ApJ Letter
Thrombotic Lesion of the Pulmonary Vessels in Patients with Pulmonary Embolism
After suffering pulmonary embolism (PE), doctors are confronted with various consequences of the disease, from asymptomatic residual pulmonary thrombosis to the formation of chronic thromboembolic pulmonary hypertension (CTEPH). There is also a subgroup of patients who have undergone pulmonary embolism, who experience shortness of breath during physical exertion, absent before pulmonary embolism, or shortened dyspnea preceding PE, combined with residual thrombosis of pulmonary artery (PA) and normal average pressure in PA at rest during catheterization of the right heart (CRH). This condition is defined as chronic thromboembolic pulmonary disease or post thromboembolic syndrome. Pathogenetic aspects of this condition are not fully investigated. It is important to predict the development of postembolic syndrome and to develop algorithms for the diagnosis, treatment and rehabilitation of patients with symptoms and residual pulmonary thrombosis. In case of the development of pulmonary vasculopathy in some patients who have undergone pulmonary embolism, a severe life-threatening condition forms - CTEPH, characterized by an increase in pressure in the pulmonary artery, right heart failure due to the presence of organized blood clots that have entered the pulmonary vascular bed during PE. The volume of thrombotic masses does not always correlate with clinical symptoms, which indicates the importance of microvascular remodeling. If CTEPH is suspected, a diagnostic algorithm is required, including ventilation-perfusion scintigraphy, CT angiopulmonography and catheterization of the right heart. Treating a patient with CTEPH is a difficult task fora doctor. The timely referral of the patient to the center where they are involved in treatment, including surgery and CTEPH is extremely important. Timely performed thrombendarterectomy in some cases allows to completely cure the patient. In the case of inoperable CTEPH or residual pulmonary hypertension after thrombendarterectomy, balloon angioplasty of the PA is used as well as drug treatment with specific drugs that reduce the pressure in the PA (riociguat), endothelin receptor antagonists (bosentan, macitentan), prostanoids (inhalant illoprost) phosphodiesterase-5 inhibitor and combined therapy. In this article we considered some consequences directly related to PE: asymptomatic residual pulmonary thrombosis, chronic thromboembolic pulmonary disease, chronic thromboembolic pulmonary hypertension
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