The Experimental Bioengineering of Complete Spinal Cord Injury in Adult Rats

The chapter is devoted to the research of experimental complete mechanical spinal injury in adult rats and attempts at bioengineering restoration of the structure and function of the spinal cord using a protein-polysaccharide construct that includes bovine collagen, highly purified crab chitosan ascorbate, nanostructuring additives in the form of sodium chondroitin sulfate, sodium hyaluronate, heparin sulfate in the presence of complete nutrient medium DMEM, neural supplement N2, conditioned nutrient medium, obtained about brain cell mouse embryos and mouse embryonic stem cells, retinoic acid, and mouse neural progenitor cells derived from embryonic stem cells. After a complete intersection of the spinal cord at the level of the ninth thoracic vertebra, the authors directly implanted a collagen-chitosan construct into the gap between the ends of the spinal cord. Analysis of the recovery of motor and sensory and vegetative functions of the spinal cord for 20 weeks after surgery using the cytological immune-fluorescent method showed a high viability of the transplanted neural cell precursors during the entire observation period and the early emergence of activity of mediators of nerve signal transmission in the implantation zone of the structure with accompaniment active dynamics of reducing neurodeficiency

Structural materials modification during plasmochemical synthesis enriched with nanoparticles

The chemical composition of nanodispersed compositions was determined: SiC, TiC, TiN, Ti(CN), AlN, Mg₂Si, Mg₃N₂. The chemical composition of the synthesized compounds corresponded to the stoichiometric composition. An analysis of particles microdiffraction patterns was carried out, it was shown that nanopowders belongs to solid crystalline bodies with a metallic bond. It has been established that Ti(CN) titanium carbonitride particles are facecentered, and silicon carbide (SiC) have a hexagonal crystal lattice. Experiments on the surface modification of steels with nanopowder compositions based on Ti(CN) and SiC have been carried out. The effectiveness of using nanodispersed compositions in the smelting of structural steels has been established. As a result of the 09G2S steel modification with Ti(CN) nanopowder, the strength, plastic properties and toughness were increased. The choosing of nanodispersed Ti(CN) carbonitride powders with a fraction less than 100 nm as modifiers of low-alloy steels was substantiated. The necessary criteria for the selection of nanopowder modifiers were obtained: insolubility in melt, conformity of the crystal lattices with the matrix of steel, proportionality with the critical radius of the austenite nucleus during crystallization. The mechanism of a steel melt interaction with a layer of a nanodisperse composition was determined.Визначено хімічний склад нанодисперсних композицій: SiC, TiC, TiN, Ti(CN), AlN, Mg₂Si, Mg₃N₂. Хімічний склад синтезованих сполук відповідав стехіометричному складу. Проведено аналіз мікродифракційних картин частинок, показана належність нанопорошків до твердих кристалічних тіл з металевим зв'язком. Встановлено, що частинки карбонітриду титану Ti(CN) мають гранецентровану, а карбіду кремнію SiC гексагональну кристалічні решітки. Були проведені експерименти з поверхневого модифікування сталей нанопорошковими композиціями на основі Ti(CN) і SiC. Встановлено ефективність застосування нанодисперсних композицій при виплавці конструкційних сталей. В результаті модифікування сталі 09Г2С нанопорошком Ti(CN) підвищені характеристики міцності, пластичності і ударна в'язкість. Обґрунтовано вибір нанодисперсних порошків карбонітриду титану Ti(CN) фракції менше 100 нм в якості модифікаторів низьколегованих сталей. Отримані необхідні критерії вибору нанопорошкових модифікаторів: нерозчинність у розплаві, відповідність кристалічних решіток з матрицею сталі, співмірність з критичним радіусом зародка аустеніту при кристалізації. Встановлено механізм взаємодії сталевого розплаву з шаром нанодисперсної композиції.Определен химический состав нанодисперсных композиций: SiC, TiC, TiN, Ti(CN), AlN, Mg₂Si, Mg₃N₂. Химический состав синтезированных соединений соответствовал стехиометрическому составу. Проведен анализ микродифракционных картин частиц, показана принадлежность нанопорошков к твердым кристаллическим телам с металлической связью. Установлено, что частицы карбонитрида титана Ti(CN) имеют гранецентрированную, а карбида кремния SiC гексагональную кристаллические решетки. Проведены эксперименты по поверхностному модифицированию сталей нанопорошковыми композициями на основе Ti(CN) и SiC. Установлена эффективность применения нанодисперсных композиций при выплавке конструкционных сталей. В результате модифицирования стали 09Г2С нанопорошком Ti(CN) повышены прочностные, пластические свойства и ударная вязкость. Обоснован выбор нанодисперсных порошков карбонитрида титана Ti(CN) фракции менее 100 нм в качестве модификаторов низколегированных сталей. Получены необходимые критерии выбора нанопорошковых модификаторов: нерастворимость в расплаве, соответствие кристаллических решеток с матрицей стали, соразмерность с критическим радиусом зародыша аустенита при кристаллизации. Установлен механизм взаимодействия стального расплава со слоем нанодисперсной композиции

Electron beam size measurements in the Fermilab Electron Cooling System

The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide maximum cooling of the antiprotons in the Recycler. A measurement system was developed using movable apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper will focus on results of these measurements of the beam size and the difficulties in making those measurements

Optical method for detecting variations of the magnetic field strength

A method of detecting the magnetic field variation is proposed and implemented experimentally. The method employs the rotation of the speckle pattern of light transmitted through an optical fiber that is placed into a longitudinal magnetic field and the recording of a holographic grating in a photorefractive crys-tal using the speckle field. The possibility of detecting the shape of a 0.15-s magnetic field pulse is demon-strated experimentally. © Pleiades Publishing, Ltd., 2011

Polarized light propagation along a helical trajectory

The results of experimental observation of a speckle pattern of light propagating through multimode optical fibers coiled into spiral are presented. The rotation of the speckle pattern has been observed. It has been shown that the angle of the speckle pattern rotation (in radians) is numerically equal to the solid angle (in steradians) subtended by the trajectory tangential vector at the unit sphere. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).Consejo Nacional de Ciencia y Tecnologia;Centro de Investigaciones en Optica, A.C.;Instituto Nacional de Astrofisica, Optica y Electronica;Universidad Nacional Autonoma de Mexico;Cent. Invest. Cient. Educ. Super. Ensenad

Magnetic properties of the natural and isotope-modified diamond and silicon carbide

The magnetic properties of single crystals of synthetic diamond and crystals of silicon carbide were studied. High-purity samples of diamonds synthesized with HPHT and CVD technologies were used. The crystals of silicon carbide were grown by sublimation and industrial technology. Along with samples with a natural isotopic composition, monoisotopic crystals of diamond (99.96% 12C and 99.96% 13C) and silicon carbide (99.993% of 28Si) were studied. On the basis of the data obtained, the diamagnetic susceptibility was determined and the concentration of paramagnetic centers and the content of the ferromagnetic component were evaluated. The results are discussed

Titanium-based high-melting nanodispersed compositions obtaining and study

Crystallographic characteristics of nanodispersed materials obtained by plasma-chemical synthesis were studied. Using industrial equipment for plasma-chemical synthesis the nanodispersed powders of high-melting carbide, nitride, carbonitride and silicide class compounds based on titanium, magnesium, aluminium, silicon were obtained. Technology for synthesis of powder fraction less than 100 nm was developed. The efficiency of nanodisperse compositions use in smelting of structural steels was determined. In the result of 10Γ2C steel modification with Ti(CN) nanopowder properties may by notice ably enhanced. Elemental composition of nanodispersed composition was determined: SiC, TiC, TiN, Ti(CN), AlN, Mg2Si, Mg3N2. The elemental composition of synthesized compounds corresponded to stoichiometric composition. Microdiffractional patterns of the particles were analyzed; it was shown that nanopowders belong to the solid crystalline bodies with metallic bond. It has been found, that titanium carbonitride Ti(CN) particles have face-centered crystal lattice, while silicon carbide (SiC) particles have hexagonal lattice. Experiments for steel 10Γ2 and 10Γ2C modifying with nanopowder compositions on base of Ti(CN) and SiC were carried out. The efficiency of nanodisperse compositions use in smelting of structural steels was determined. In the result of 10Γ2C steel modification with Ti(CN) nanopowder strength, plastic properties and impact toughness were improved. The choice of nanodisperse titanium carbonitride Ti(CN) powders with 100 nm fraction for light alloy steels modifying was justified. The required criteria for choice of nanopowder modifiers were obtained: insolubility in smelt, correspondence of crystal lattice to steel matrix, commensurability with austenite germ critical radius in crystallizing

Magnetic properties of the natural and isotope-modified diamond and silicon carbide

The magnetic properties of single crystals of synthetic diamond and crystals of silicon carbide were studied. High-purity samples of diamonds synthesized with HPHT and CVD technologies were used. The crystals of silicon carbide were grown by sublimation and industrial technology. Along with samples with a natural isotopic composition, monoisotopic crystals of diamond (99.96% 12C and 99.96% 13C) and silicon carbide (99.993% of 28Si) were studied. On the basis of the data obtained, the diamagnetic susceptibility was determined and the concentration of paramagnetic centers and the content of the ferromagnetic component were evaluated. The results are discussed

Behavioral Studies and Genetic Alterations in Corticotropin-Releasing Hormone (CRH) Neurocircuitry: Insights into Human Psychiatric Disorders

To maintain well-being, all organisms require the ability to re-establish homeostasis in the presence of adverse physiological or psychological experiences. The regulation of the hypothalamic-pituitary adrenal (HPA) axis during stress is important in preventing maladaptive responses that may increase susceptibility to affective disorders. Corticotropin-releasing hormone (CRH) is a central stress hormone in the HPA axis pathway and has been implicated in stress-induced psychiatric disorders, reproductive and cardiac function, as well as energy metabolism. In the context of psychiatric disorders, CRH dysfunction is associated with the occurrence of post-traumatic stress disorder, major depression, anorexia nervosa, and anxiety disorders. Here, we review the synthesis, molecular signaling and regulation, as well as synaptic activity of CRH. We go on to summarize studies of altered CRH signaling in mutant animal models. This assembled data demonstrate an important role for CRH in neuroendocrine, autonomic, and behavioral correlates of adaptation and maladaptation. Next, we present findings regarding human genetic polymorphisms in CRH pathway genes that are associated with stress and psychiatric disorders. Finally, we discuss a role for regulators of CRH activity as potential sites for therapeutic intervention aimed at treating maladaptive behaviors associated with stress