340 research outputs found
Quantum confinement in Si and Ge nanostructures: Effect of crystallinity
We look at the relationship between the preparation method of Si and Ge
nanostructures (NSs) and the structural, electronic, and optical properties in
terms of quantum confinement (QC). QC in NSs causes a blue shift of the gap
energy with decreasing NS dimension. Directly measuring the effect of QC is
complicated by additional parameters, such as stress, interface and defect
states. In addition, differences in NS preparation lead to differences in the
relevant parameter set. A relatively simple model of QC, using a
`particle-in-a-box'-type perturbation to the effective mass theory, was applied
to Si and Ge quantum wells, wires and dots across a variety of preparation
methods. The choice of the model was made in order to distinguish contributions
that are solely due to the effects of QC, where the only varied experimental
parameter was the crystallinity. It was found that the hole becomes
de-localized in the case of amorphous materials, which leads to stronger
confinement effects. The origin of this result was partly attributed to
differences in the effective mass between the amorphous and crystalline NS as
well as between the electron and hole. Corrections to our QC model take into
account a position dependent effective mass. This term includes an inverse
length scale dependent on the displacement from the origin. Thus, when the
deBroglie wavelength or the Bohr radius of the carriers is on the order of the
dimension of the NS the carriers `feel' the confinement potential altering
their effective mass. Furthermore, it was found that certain interface states
(Si-O-Si) act to pin the hole state, thus reducing the oscillator strength.Comment: arXiv admin note: substantial text overlap with arXiv:1111.201
New methods to detect early manifestations of adverse side effects of glucocorticosteroids in children
The article focuses on the early manifestations of adverse side effects in children with nephrotic syndrome receiving glucocorticosteroids. The search for criteria of early side effect manifestations is a real challenge nowadays. The authors developed new diagnostic criteria for early detection of pharmacotherapeutical side effects in children with nephrotic syndrom
Complex therapy of chronic pancreatitis complicated by anxio-depressive disorders in railroad workers
The authors have found out negative impact of anxio-depressive disorders on the course of chronic pancreatitis with the development of stable pain syndrome, gastro-intestinal disorders, resistance to the performed pharmacotherapy, and decrease of reaction rate to presented stimul
HugeNon-Organ Retroperitoneal Tumor inCombination with aCystoma of Uterine Appendages
The article describes the experience of successful diagnostics and treatment of giant non-organ extraperitoneal tumor combined with a cystoma of uterine appendages.Patient P., 43 years old, was hospitalized in the oncology department, diagnosed with “Abdominal tumor, right ovary?” The state was satisfactory, after palpation of the abdomen, a lumpy formation of a densely elastic consistency, from the womb to the epigastric region, was found. An ultrasound revealed a homogeneous tumor formation 30×28 cm from the border of the uterus to the liver. When performing median laparotomy, a dumbbell-shaped tumor (36×26×20 cm) was found in the retroperitoneal space with involvement of the mesentery of the small intestine, lower horizontal portion of the duodenum, mesentery of the transverse colon, superior mesenteric vessels, aorta and jejunum. In the right appendages, a cystoma 12–15 cm in diameter was found, with inversion and necrosis. Adnexectomy was performed. An express lymph node biopsy revealed cells suspicious for malignancy. The tumor was mobilized and removed as a single unit with retroperitoneal tissue, lymph nodes in combination with resection of 70 cm of the jejunum and fenestrated resection of the duodenum. The resulting gut defect 9×7 cm was sutured with a precision single-row suture. Inter-intestinal anastomosis “endto-end” was formed. Nasointestinal intubation was performed. The abdominal cavity was sutured, and two tubular drainages were installed. The postoperative period was uneventful. The histological conclusion: fibrous histiocytoma of the mesentery of the intestine with malignancy in the center of the node, in the ovary – total hemorrhagic infiltration of all layers, edema. The tumor conference consultation was recommended. After 1.5 years, the patient was admitted with the same clinical picture. During laparotomy, a tumor recurrence was discovered, the nodes of which were located in the retroperitoneal space, in the abdominal cavity with invasion to organs and large vessels. The case was recognized as inoperable, the laparotomic wound was closed completely. Sixteen days after surgery the patient was discharged
Information technologies in obrizovatelny process
Use of information technologies allows to switch to effective and economic (resource-saving) educational technologies. It means, we have an opportunity to learn not only to knowledge, but first of all competences, that is abilities and practical experience. To teach not a profession, but professionalismИспользование информационных технологий позволяет перейти на использование эффективных и экономически выгодных (ресурсосберегающих) образовательных технологий. Это значит, мы имеем возможность учить не только знаниям, но прежде всего компетенциям, то есть умениям и практическому опыту. Учить не профессии, а профессионализм
Electromagnetic dissociation of relativistic B nuclei in nuclear track emulsion
Experimental data on fragmentation channels in peripheral interactions of
B nuclei in nuclear track emulsions are presented. A detailed analysis made
it possible to justify selections of events of the electromagnetic-dissociation
process B Be + \emph{p} and to estimate its cross section. Events of
C peripheral dissociation that were observed in the same exposure are
described.Comment: 12 pages, 10 figures, 4 tables, Published in
Phys.Atom.Nucl.72:690-701,200
Solid-phase luminescence determination of tetracycline in bottled water using chemically modified silica
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