Stimulated wave of polarization in spin chains

Stimulated wave of polarization, triggered by a flip of a single spin, presents a simple model of quantum amplification. Previously, it has been found that such wave can be excited in a 1D Ising chain with nearest-neighbor interactions, irradiated by a weak resonant transverse field. Here we explore models with more realistic Hamiltonians, in particular, with natural dipole-dipole interactions. Results of simulations for 1D spin chains and rings with up to nine spins are presented.Comment: 15 pages, 5 figure

The TRC8 E3 ligase ubiquitinates MHC class I molecules before dislocation from the ER

Human cytomegalovirus uses an E3 ubiquitin ligase to divert MHC I molecules into the ER-associated degradation pathway for destruction

FIEFDom: a transparent domain boundary recognition system using a fuzzy mean operator

Protein domain prediction is often the preliminary step in both experimental and computational protein research. Here we present a new method to predict the domain boundaries of a multidomain protein from its amino acid sequence using a fuzzy mean operator. Using the nr-sequence database together with a reference protein set (RPS) containing known domain boundaries, the operator is used to assign a likelihood value for each residue of the query sequence as belonging to a domain boundary. This procedure robustly identifies contiguous boundary regions. For a dataset with a maximum sequence identity of 30%, the average domain prediction accuracy of our method is 97% for one domain proteins and 58% for multidomain proteins. The presented model is capable of using new sequence/structure information without re-parameterization after each RPS update. When tested on a current database using a four year old RPS and on a database that contains different domain definitions than those used to train the models, our method consistently yielded the same accuracy while two other published methods did not. A comparison with other domain prediction methods used in the CASP7 competition indicates that our method performs better than existing sequence-based methods

Оценка биомеханики позвоночно-двигательного сегмента у больных с множественными грыжами шейного отдела позвоночника, оперированных методикой пункционной лазерной микродискэктомии

Нами проведен анализ основных параметров позвоночно-двигательного сегмента у 55 пациентов, оперированных в условиях ГУ «Институт нейрохирургии им. А. П. Ромоданова НАМН Украины» в период с 1997 по 2016 гг. по поводу множественных грыж шейного отдела позвоночника методикой пункционной лазерной микродискэктомии. Результаты нашего исследования свидетельствуют об отсутствии биомеханических изменений в оперированном позвоночно-двигательном сегменте в разные сроки наблюдений. Таким образом, методика пункционной лазерной микродискэктомии является малоинвазивным методом хирургического лечения больных с множественными грыжами шейного отдела позвоночника и не вызывает изменения биомеханики на уровне оперированного позвоночно-двигательного сегмента.According to the literature, the stability of the vertebral-motion segment by 40–60% is provided by the intervertebral disc . Disruption of the structure of the intervertebral disc leads to a disruption in the stability of the vertebral-motion segment. Puncture laser microdiscectomy opened the era of outpatient surgery in the treatment of patients with discogenic neurocompression syndromes. Regression of pain syndrome in discogenic spine syndromes occurs as a result of the creation of decompression, derepression, and microfenestration of the intervertebral disc. Performing laser vaporization also stimulates the development of fibrosis in the intervertebral disc, and subsequently contribute to the stabilization of the vertebral-motion segment. To evaluate the biomechanics of the vertebral-motion segment in patients with discogenic neurocompression syndromes, caused by multiple hernias of the cervical spine, operated by the method of puncture laser microdiscectom

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Initial Decomposition Reactions of Bicyclo-HMX [BCHMX or cis

We investigated the initial chemical reactions of BCHMX [cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole] with the following procedure. First we used density functional theory molecular dynamics simulations (DFT-MD) on the periodic crystal to discover the initial reaction steps. This allowed us to determine the most important reactions through DFT-MD simulations at high temperatures. Then we started with the midpoint of the reaction (unimolecular or bimolecular) from the DFT-MD and carried out higher quality finite cluster DFT calculations to locate the true transition state of the reaction, followed by calculations along the reaction path to determine the initial and final states. We find that for the noncompressed BCHMX the nitro-aci isomerization reaction occurs earlier than the NO2-releasing reaction, while for compressed BCHMX intermolecular hydrogen-transfer and bimolecular NO2-releasing reactions occur earlier than the nitrous acid (HONO)-releasing reaction. At high pressures, the initial reaction involves intermolecular hydrogen transfer rather than intramolecular hydrogen transfer, and the intermolecular hydrogen transfer decreases the reaction barrier for release of NO2 by ∼7 kcal/mol. Thus, the HONO-releasing reaction takes place more easily in compressed BCHMX. We find that this reaction barrier is 10 kcal/mol lower than the unimolecular NO2 release and ∼3 kcal/mol lower than the bimolecular NO2 release. This rationalizes the origin of the higher sensitivity of BCHMX compared to RDX (1,3,5-trinitrohexahydro-1,3,5-triazine) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). We suggest changes in BCHMX that might help decrease the sensitivity by avoiding the intermolecular hydrogen-transfer and HONO-releasing reaction

Enterocolitis necrotizante en recién nacidos ingresados en el Servicio de Neonatología del Hospital Escuela "Carlos Roberto Huembes" en el período comprendido de Enero 2011 a Diciembre 2013

La enterocolitis necrotizante en el recién nacido presenta un amplio espectro de manifestaciones clínicas, caracterizándose principalmente por la tríada de distensión abdominal, sangramiento gastrointestinal y neumatosis intestinal. A pesar del avance en el cuidado intensivo neonatal, persiste como una enfermedad grave, que afecta habitualmente al recién nacido pretérmino, especialmente de muy bajo peso