132 research outputs found
Silver(I) triflate-catalyzed protocol for the post-ugi synthesis of spiroindolines
A silver(I) triflate-catalyzed protocol for the post-Ugi synthesis of tetracyclic spiroindolines has been developed. The protocol worked best for indole-3-carbaldehyde-derived Ugi adducts obtained using anilines and 3-aryl propiolic acids. Thus, it is complementary to the previous cationic gold-catalyzed procedure that was developed for analogues Ugi substrates derived from aliphatic amines and 3-alkyl propiolic acids. Furthermore, we have demonstrated that under our new settings this domino Friedel-Crafts ipso cyclization / imine trapping process could be efficiently combined with the preceding four-component Ugi reaction into a two-step one-pot transformation
U(1)-Symmetry breaking and violation of axial symmetry in TlCuCl3 and other insulating spin systems
We describe the Bose-Einstein condensate of magnetic bosonic quasiparticles
in insulating spin systems using a phenomenological standard functional method
for T = 0. We show that results that are already known from advanced
computational techniques immediately follow. The inclusion of a perturbative
anisotropy term that violates the axial symmetry allows us to remarkably well
explain a number of experimental features of the dimerized spin-1/2 system
TlCuCl3. Based on an energetic argument we predict a general intrinsic
instability of an axially symmetric magnetic condensate towards a violation of
this symmetry, which leads to the spontaneous formation of an anisotropy gap in
the energy spectrum above the critical field. We, therefore, expect that a true
Goldstone mode in insulating spin systems, i.e., a strictly linear
energy-dispersion relation down to arbitrarily small excitations energies,
cannot be observed in any real material.Comment: 6 pages, 3 figure
Relationship between prostate cancer and type 2 diabetes mellitus
Type 2 diabetes mellitus (DM2) and prostate cancer are widespread diseases throughout the world. Type II diabetes mellitus is accompanied by a deterioration in glycemic control, hyperinsulinemia, and insulin resistance (IR). The accumulation of glucose and lipids leads to a decrease in the density of insulin receptors and the development of insulin resistance in adipose tissue. This contributes to the development of hyperinsulinemia, which suppresses the breakdown of fat and leads to the progression of obesity. A vicious circle develops: insulin resistance → hyperinsulinemia → obesity → insulin resistance. Insulin influences the progression of the cell cycle, proliferation, and metastatic activity of the tumor.Recent studies have shown a strong direct correlation between fasting insulin levels and cancer mortality in men. This may be especially true in patients over 65, who are, in the first place, more likely to develop prostate cancer than younger patients. It should be noted that it is insulin, and not glucose, that is associated with the claim for the development of cancer. Hyperinsulinemia, which often occurs as a result of androgen deprivation therapy (ADT), the standard treatment for prostate cancer, is associated with a high tumor aggressiveness and faster treatment failure — the development of castrate-refractory prostate cancer. It is reasonable to assume that hyperinsulinemia — under whatever circumstances it is caused, whether due to ADT or due to inadequate nutrition and other lifestyle factors — can have the same negative effect on cellular signaling.Metabolic syndrome — essentially chronically elevated insulin levels — is closely associated with recurrence of cancer and worse post-treatment outcomes, which has led researchers to question generally accepted dietary guidelines for cancer patients, especially when they are undergoing treatment or recover from treatment, which may include recommendations to consume anything that will help maintain or restore body weight, regardless of sugar or carbohydrate content or its effect on insulin levels. A large number of patients live with hyperinsulinemia, but normoglycemia. Chronic hyperinsulinemia is the main driver of cardiometabolic disease, even when blood sugar levels are within reference values. The scale of this problem is not recognized by the medical and scientific community
The relationship of obesity and prostate cancer (review)
Obesity is a critical risk factor for prostate cancer (PCa). Adipose tissue plays an important role in tumor development, including growth, invasion, and metastasis. Diet and dietary components affect the progression of prostate cancer; however, the mechanisms underlying these associations remain unclear. Extraprostatic prostate tumor cells form a new microenvironment in the periprostatic adipose tissue, which alters these interactions and promotes tumor progression. Hyperinsulinemia leads to an increase in the level of free or biologically active insulin-like growth factor (IGF-1) due to a decrease in the production of IGF-binding proteins. Hypoandrogenism promotes the development of a more aggressive type of prostate cancer (higher Gleason scores). Adipokines of adipose tissue and cytokines (for example, interleukin-6 (IL-6) and tumor necrosis factor (TNF-α), angiogenic factors (for example, vascular endothelial growth factor (VEGF), apelin (AGTRL1) and other factors (for example, leptin and adiponectin) have multiple effects on prostate cancer cells. Tumor cells interact directly or indirectly with adipocytes. Yellow (inactive) bone marrow is adipose tissue with separate islands of reticular tissue. It is located in the medullary canals of the tubular bones and in parts of the cells of the cancellous bone. Bone tissue is the object of the most frequent metastasis in prostate cancer, and with age, the content of fat cells in it increases. Bone marrow adipose tissue interacts with tumor cells, osteoblasts and other stromal cells and participates in the organization of the tumor microenvironment. Adipokines are key molecules in the interaction between tumor cells and adipose tissue, which is carried out through various mechanisms. A better understanding of the role of adipose tissue in the induction and progression of prostate cancer will lead to effective therapeutic strategies for this disease
Metabolic changes in patients with prostate cancer with androgen deprivation therapy
Prostate cancer is the most common type of cancer among men. Androgen deprivation therapy (ADT) is the most effective treatment for this disease. The cornerstone of prostate cancer treatment is the inhibition of testosterone production, which interrupts testosterone-induced growth of the prostate tumour. A sharp decrease in testosterone, however, has several undesirable effects on the metabolic profile and bone metabolism and can also lead to fatigue, loss of libido, gynecomastia and anaemia, provoke vasomotor hyperaemia and generally affect the quality of life. To increase the good (long-term) survival of patients with prostate cancer, studying the side effects associated with treatment is important, and therefore, in every clinical situation, the benefits of ADT must be compared with the side effects associated with the treatment. This article focuses on the described metabolic complications of ADT, including obesity, diabetes, lipid changes, metabolic syndrome and cardiovascular diseases. It also contains practical recommendations for managing the side effects and complications based on the available guidelines issued by the medical professional community
Quantum fluids of light
This article reviews recent theoretical and experimental advances in the
fundamental understanding and active control of quantum fluids of light in
nonlinear optical systems. In presence of effective photon-photon interactions
induced by the optical nonlinearity of the medium, a many-photon system can
behave collectively as a quantum fluid with a number of novel features stemming
from its intrinsically non-equilibrium nature. We present a rich variety of
photon hydrodynamical effects that have been recently observed, from the
superfluid flow around a defect at low speeds, to the appearance of a
Mach-Cherenkov cone in a supersonic flow, to the hydrodynamic formation of
topological excitations such as quantized vortices and dark solitons at the
surface of large impenetrable obstacles. While our review is mostly focused on
a class of semiconductor systems that have been extensively studied in recent
years (namely planar semiconductor microcavities in the strong light-matter
coupling regime having cavity polaritons as elementary excitations), the very
concept of quantum fluids of light applies to a broad spectrum of systems,
ranging from bulk nonlinear crystals, to atomic clouds embedded in optical
fibers and cavities, to photonic crystal cavities, to superconducting quantum
circuits based on Josephson junctions. The conclusive part of our article is
devoted to a review of the exciting perspectives to achieve strongly correlated
photon gases. In particular, we present different mechanisms to obtain
efficient photon blockade, we discuss the novel quantum phases that are
expected to appear in arrays of strongly nonlinear cavities, and we point out
the rich phenomenology offered by the implementation of artificial gauge fields
for photons.Comment: Accepted for publication on Rev. Mod. Phys. (in press, 2012
Why hyperbolic theories of dissipation cannot be ignored: Comments on a paper by Kostadt and Liu
Contrary to what is asserted in a recent paper by Kostadt and Liu ("Causality
and stability of the relativistic diffusion equation"), experiments can tell
apart (and in fact do) hyperbolic theories from parabolic theories of
dissipation. It is stressed that the existence of a non--negligible relaxation
time does not imply for the system to be out of the hydrodynamic regime.Comment: 8 pages Latex, to appear in Phys.Rev.
Social status and satisfaction of the phlebosurgical patient
The purpose of the study is to give a medical and social characteristic of patients treated for chronic diseases of the veins of the lower extremities in an outpatient phlebological center.Цель исследования – дать медико-социальную характеристику пациентов, лечившихся по поводу хронических заболеваний вен нижних конечностей в амбулаторном флебологическом центре
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