Adipose tissue (AT) optical properties for physiological temperatures and in vivo conditions are still insufficiently studied. The AT is composed mainly of packed cells close to spherical shape. It ...is a possible reason that AT demonstrates a very complicated spatial structure of reflected or transmitted light. It was shown with a cellular tissue phantom, is split into a fan of narrow tracks, originating from the insertion point and representing filament-like light distribution. The development of suitable approaches for describing light propagation in a AT is urgently needed. A mathematical model of the propagation of light through the layers of fat cells is proposed. It has been shown that the sharp local focusing of optical radiation (light localized near the shadow surface of the cells) and its cleavage by coupling whispering gallery modes depends on the optical thickness of the cell layer. The optical coherence tomography numerical simulation and experimental studies results demonstrate the importance of sharp local focusing in AT for understanding its optical properties for physiological conditions and at AT heating.
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We study a two-dimensional (2-D) potential flow of an ideal fluid with a free surface with decaying conditions at infinity. By using the conformal variables approach, we study a particular solution ...of the Euler equations having a pair of square-root branch points in the conformal plane, and find that the analytic continuation of the fluid complex potential and conformal map define a flow in the entire complex plane, excluding a vertical cut between the branch points. The expanded domain is called the ‘virtual’ fluid, and it contains a vortex sheet whose dynamics is equivalent to the equations of motion posed at the free surface. The equations of fluid motion are analytically continued to both sides of the vertical branch cut (the vortex sheet), and additional time invariants associated with the topology of the conformal plane and Kelvin's theorem for a virtual fluid are explored. We called them ‘winding’ and virtual circulation. This result can be generalized to a system of many cuts connecting many branch points, resulting in a pair of invariants for each pair of branch points. We develop an asymptotic theory that shows how a solution originating from a single vertical cut forms a singularity at the free surface in infinite time, the rate of singularity approach is double exponential and supersedes the previous result of the short branch cut theory with finite time singularity formation. The present work offers a new look at fluid dynamics with a free surface by unifying the problem of motion of vortex sheets, and the problem of 2-D water waves. A particularly interesting question that arises in this context is whether instabilities of the virtual vortex sheet are related to breaking of steep ocean waves when gravity effects are included.
The influence of ischemia–reperfusion (I/R) action on pancreatic blood flow (PBF) and the development of acute pancreatitis (AP) in laboratory rats is evaluated in vivo by using the laser speckle ...contrast imaging (LSCI). Additionally, the optical properties in norm and under condition of AP in rats were assessed using a modified integrating sphere spectrometer and inverse Monte Carlo (IMC) software. The results of the experimental study of microcirculation of the pancreas in 82 rats in the ischemic model are presented. The data obtained confirm the fact that local ischemia and changes in the blood flow velocity of the main vessels cause and provoke acute pancreatitis.
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We address the problem of the potential motion of an ideal incompressible fluid with a free surface and infinite depth in a two-dimensional geometry. We admit the presence of gravity forces and ...surface tension. A time-dependent conformal mapping
$z(w,t)$
of the lower complex half-plane of the variable
$w$
into the area filled with fluid is performed with the real line of
$w$
mapped into the free fluid’s surface. We study the dynamics of singularities of both
$z(w,t)$
and the complex fluid potential
$\unicodeSTIX{x1D6F1}(w,t)$
in the upper complex half-plane of
$w$
. We show the existence of solutions with an arbitrary finite number
$N$
of complex poles in
$z_{w}(w,t)$
and
$\unicodeSTIX{x1D6F1}_{w}(w,t)$
which are the derivatives of
$z(w,t)$
and
$\unicodeSTIX{x1D6F1}(w,t)$
over
$w$
. We stress that these solutions are not purely rational because they generally have branch points at other positions of the upper complex half-plane. The orders of poles can be arbitrary for zero surface tension while all orders are even for non-zero surface tension. We find that the residues of
$z_{w}(w,t)$
at these
$N$
points are new, previously unknown, constants of motion, see also Zakharov & Dyachenko (2012, authors’ unpublished observations,
arXiv:1206.2046
) for the preliminary results. All these constants of motion commute with each other in the sense of the underlying Hamiltonian dynamics. In the absence of both gravity and surface tension, the residues of
$\unicodeSTIX{x1D6F1}_{w}(w,t)$
are also the constants of motion while non-zero gravity
$g$
ensures a trivial linear dependence of these residues on time. A Laurent series expansion of both
$z_{w}(w,t)$
and
$\unicodeSTIX{x1D6F1}_{w}(w,t)$
at each poles position reveals the existence of additional integrals of motion for poles of the second order. If all poles are simple then the number of independent real integrals of motion is
$4N$
for zero gravity and
$4N-1$
for non-zero gravity. For the second-order poles we found
$6N$
motion integrals for zero gravity and
$6N-1$
for non-zero gravity. We suggest that the existence of these non-trivial constants of motion provides an argument in support of the conjecture of complete integrability of free surface hydrodynamics in deep water. Analytical results are solidly supported by high precision numerics.
To explain the nature of the high reddening (A
V
≃ 10 mag) towards one of the most luminous stars in the Galaxy – Cyg OB2 #12 (B5 Ia-0), also known as MT304, we carried out spectrophotometric ...observations of 24 stars located in its vicinity. We included five new B-stars among the members of Cygnus OB2, and for five more photometrically selected stars we spectroscopically confirmed their membership. We constructed the map of interstellar extinction within 2.5 arcmin radius and found that interstellar extinction increases towards MT304. According to our results the most reddened OB-stars in the association after MT304 are J203240.35+411420.1 and J203239.90+411436.2, located about 15 arcsec away from it. Interstellar extinction towards these stars is about 9 mag. The increase of reddening towards MT304 suggests that the reddening excess may be caused by the circumstellar shell ejected by the star during its evolution. This shell absorbs 1 mag, but its chemical composition and temperature are unclear. We also report the detection of a second component of MT304, and discovery of an even fainter third component, based on data of speckle interferometric observations taken with the Russian 6-m telescope.
Fused 2-amino-3-cyano-4
H
-pyrans were synthesized by the tandem Knoevenagel—Michael reaction. A previously unknown version of the ring opening of 2-amino-3-cyano-4
H
-pyrans giving substituted ...2,6-dicyanoaniline was discovered. The structure of the latter compound was established by X-ray diffraction.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The multicomponent condensation of cyclopentylidene- or cyclohexylidenemalononitrile, cyanoacetic acid amides or thioamides, and alkylating agents affords 4-spirocyclopentane- and ...4-spirocyclohexanenicotinic acid nitriles and amides. The structures of several reaction products were determined by X-ray diffraction.
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New nicotinamide derivatives have been synthesized by reactions of enamino ketones, aryl(hetaryl)methylidenecyanothioacetamides, alkylating agents, formamide, and cycloalkanones. The structure of ...some of the synthesized compounds has been determined by X-ray analysis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
10.
New Synthesis of Tetrahydroisoquinolines Dyachenko, I. V.; Dyachenko, V. D.; Dorovatovskii, P. V. ...
Russian journal of organic chemistry,
05/2022, Volume:
58, Issue:
5
Journal Article
Peer reviewed
The reaction of cyclohexylidenecyanothioacetamide with
N
,
N
-dimethylformamide dimethyl acetal was studied. This transformation, depending on the reaction conditions, leads to different results: ...when the starting reagents are refluxed without a solvent, 3-(methylsulfanyl)-5,6,7,8-tetrahydroisoquinoline-4-carbonitrile is formed, and refluxing in benzene leads to 2-cyano-3-(dimethylamino)prop-2-enethioamide. The structure of these products was studied by XRD analysts.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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