Quantum real-space transfer in a heterostructure overgrown on the cleaved edge of a superlattice

A dispersion relation for an electron in a two-layer (and also multilayer) quantum well (QW) is formed as a result of a certain combination of initial dispersion relations for each of the forming layers. Such a combination can be used to engineer new dispersion relations with desirable properties. The same relates to a two-dimensional electron gas (2DEG) induced in a multilayer medium. In this study, we consider first such a 2DEG in a specific two-layer structure where a superlattice (SL) plays the role of the second half-infinite layer, and electrons with large wave numbers along the SL vector spread from the first ordinary QW layer to this SL. As a result of such a quantum (dynamic) real-space transfer, electrons become heavier, and the dispersion relation achieves an additional negative effective mass (NEM) section. Such NEM dispersion relations were studied for several different material systems, including the two most interesting three-material systems: (1) an isomorphic Al0.15Ga0.85As//GaAs/Al0.5Ga0.5AsAl0.15Ga0.85As//GaAs/Al0.5Ga0.5As structure and (2) a strained In0.53Ga0.47As//InxGa1−xAs/InyAl1−yIn0.53Ga0.47As//InxGa1−xAs/InyAl1−y As structure (x>0.53,(x>0.53, y<0.52)y<0.52) with a strain-balanced InxGa1−xAs/InyAl1−yAsInxGa1−xAs/InyAl1−yAs SL. Most of the results were verified using a simplified 1D model, but some of them were verified by more complicated 2D-model calculations. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70061/2/JAPIAU-93-1-330-1.pd

New NIR-emissive tetranuclear Er(III) complexes with 4-hydroxo-2,1,3-benzothiadiazolate and dibenzoylmethanate ligands: synthesis and characterization

New tetranuclear heteroleptic complexes [Er4(dbm)6(O-btd)4(OH)2] (1) and [Er4(dbm)4(O-btd)6(OH)2] (2) (O-btd = 4-hydroxo-2,1,3-benzothiadiazolate and dbm = dibenzoylmethanide) and their solvates with toluene, THF and CH2Cl2 were prepared using two synthetic approaches. The structures of the products were confirmed by single-crystal X-ray diffraction. Magnetic properties of 1 and 2 are in good agreement with X-ray data. The effective magnetic moment (μeff) values at 300 K for 1 and 2 corresponds to a system of 4 non-interacting Er(III) ions in the ground state 4J15/2 with g = 6/5. At ambient temperature and upon excitation with λexc = 450 nm, complexes 1 and 2 exhibit luminescence at ∼1530 nm, i.e. in the near infra-red (NIR) region. The luminescence intensity grows with increasing the number of the (O-btd)−ligands in the complexes. This observation suggests (O-btd)− as a new efficient antenna ligand for the lanthanide-based NIR luminescence

Micellization of alkylated 1.4-diazabicyclo[2.2.2]octane by nuclear magnetic resonance technique using pulsed gradient of static magnetic field

A phenomenon of micellization of 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2] octane bromide (AB-14) in aqueous solution has been studied by the methods of nuclear magnetic resonance using magnetic field pulse gradient and fluorimetry. The critical micelle concentration is determined; concentration dependences of percentage of free AB-14 molecules and those associated with micelles as well as radii of micelles and numbers of their aggregation are established. Effect of external and internal translational diffusion of molecules on lifetime of AB-14 molecules in micelles is investigated. © 2012 Elsevier B.V

Ультраструктура печени при действии малых доз фтора

In experiment on laboratory rats Wistars by a method of appearing through electronic microscopy of a liver it is established, that at action of small doses of fluorine (0,5 mg/kg of a fluorine-ions within 1 month) hepatocitys are exposed destructions by damp lyses, and endoteliocitys — apoptosis. A special kind destructions is migration mytochondris in kernels hepatocitys with the subsequent formation megaautohpagosomes and them lyses. In basalition to a membrane develops fibrosis and appear pathological message between space Disse and a gleam of sinusoidal capillaries. The conclusion that small doses of fluorine close to used at osteoporosis correction, cause destructive changes in a liver that does necessary to carry out the actions directed on inactivation of fluorine becomes.В эксперименте на лабораторных крысах линии Вистар методом просвечивающей электронной микроскопии печени установлено, что при действии малых доз фтора (0,5 мг фтор-ионов на 1 кг массы тела в течение 1 мес) гепатоциты подвергаются деструкции путем влажного лизиса, а эндотелиоциты — апоптозу. Особым видом деструкции является миграция митохондрий в ядра гепатоцитов с последующим образованием мегааутофагосом и их лизисом. В базальной мембране развивается фиброз и формируются патологические соустья между пространством Диссе и просветом синусоидальных капилляров. Делается вывод о том, что малые дозы фтора, близкие к используемым при коррекции остеопороза, вызывают деструктивные изменения в печени, что делает необходимым проводить мероприятия, направленные на инактивацию фтора

СТРОЕНИЕ АНАЛЬНОГО КАНАЛА И АНАЛЬНЫХ СФИНКТЕРОВ СОБАК В НОРМЕ И ПОСЛЕ ПРОКТЭКТОМИИ С НИЗВЕДЕНИЕМ ОБОДОЧНОЙ КИШКИ

With gistostereometry study the structure of the anal canal and anal sphincter dogs in norm and after proctectomy with bringing down the colon, forming neoanus and neosphinkter. The artificial sphincter is the inevitable process of smooth muscle atrophy can save at least half the volume of smooth muscle, similar to the number in the internal sphincter needed to restore function after holding involuntary proctectomy. Neoanus of mucous and submucosal colon relegated acquired typical smooth relief with the advent of the vertical pleats on the type of anal columns of Morgagni and with the perianal skin was closely associated with the subcutaneous portion of the external sphincter smooth muscle and an artificial sphincter. Thus, the experimental model of the internal sphincter and neoanus created by bringing down the mucous and the formation of smooth cuffs, very similar in quantitative and qualitative terms, the structure of the anal canal and anal sphincter dogs and can be used in clinical practice.С помощью гистостереометрии изучено строение анального канала и анальных сфинктеров собак в норме и после проктэктомии с низведением ободочной кишки, формированием неоануса и неосфинктера. Искусственный сфинктер при неизбежных процессах атрофии гладкой мускулатуры позволяет сохранить не менее половины объема гладкой мускулатуры, аналогичной количеству во внутреннем сфинктере, необходимой для восстановления функции непроизвольного держания после проктэктомии. Неоанус из слизисто-подслизистого слоя низведенной ободочной кишки приобретал типичный сглаженный рельеф с появлением вертикальных складок по типу анальных морганьевых колонн и вместе с перианальной кожей был тесно связанным с подкожной порцией наружного сфинктера и искусственным гладкомышечным сфинктером. Таким образом, экспериментальная модель внутреннего сфинктера и неоануса, созданная путем низведения слизистой и формирования гладкомышечной манжеты, очень напоминает в количественном и качественном выражении строение анального канала и анальных сфинктеров собак и может использоваться в клинической практике

Analysis of recombinant VEGF gene expression by genetically modified umbilical cord blood mononuclear cells in experiment in vivo

To obtain a significant therapeutic effect transplanted genetically modified cells should have an enhanced ability to survive and active expression of the therapeutic gene. In this paper, by using immunofluorescent staining we investigated the functional activity of the gene-cell formulation designed to deliver a therapeutic gene into the area of regeneration. As a model we used transgenic SOD1-G93A mice with amyotrophic lateral sclerosis phenotype which received xenotransplantation of human umbilical cord blood mononuclear cells, genetically modified with adenoviral expression vector encoding vascular endothelial growth factor (VEGF) and the reporter green fluorescent protein (EGFP). Results of the study allowed to establish not only the duration of survival of transplanted cells, but also the efficiency of expression of recombinant genes in genetically modified cells in vivo. Double immunofluorescent staining with antibodies against human nuclear antigen HNA and VEGF detected HNA+/VEGF+ cells in the terminal stage of disease 15 weeks after transplantation. These data suggest that genetically modified umbilical cord blood mononuclear cells, transplanted into SOD1-G93A transgenic mice, are able to penetrate the blood-brain barrier and migrate into the area of degeneration of nerve tissue and survive from the time of transplantation until the death of animals at the terminal stage of disease. At that time adenoviral expression vector encoding therapeutic gene is functionally active in transplanted cells, and secretory products of recombinant gene act on target cells by a paracrine mechanism