On the structure of the Si(103) surface

Although (103) is a stable nominal orientation for both silicon and germanium, experimental observations revealed that in the case of silicon this surface remains disordered on an atomic scale even after careful annealing. We report here a set of low-energy reconstruction models corresponding to $1\times 2$, $2\times 2$, and $1\times 4$ periodicities, and propose that the observed disorder stems from the presence of several coexisting reconstructions with different morphologies and nearly equal surface energies. These models also suggest that the model structures previously reported in the literature for the (103) orientation have very high surface energies and are thus unlikely to be experimentally observed.Comment: 4 pages, 3 figures, submitted for publicatio

Tuberculous synovitis of the knee in a 65-year-old man

Introduction. Tuberculous (TB) synovitis is a rare, treatable, potentially lethal form of extrapulmonary TB resulting from massive lymphohematogenous dissemination of Mycobacterium tuberculosis (M. tuberculosis). We presented a case of TB synovitis of the knee in a Caucasian HIV negative man from Romania, a high TB incidence country. Case report. A 65-year old man presented with cough, high fever, mild wheezing, and swelling of the left knee. Chest radiography was normal. Sputum smears were Acid Fast Bacilli negative and Löwenstein-Jensen (L-J) culture negative for M. tuberculosis. Tuberculin skin test was negative. Respiratory symptoms disappeared in a week under antibiotics. Positive L-J cultures of knee punctation and favourable treatment outcome following standardized antituberculous treatment regimen confirmed the diagnosis of specific synovitis, which was also demonstrated by Magnetic Resonance Imaging (MRI). Conclusion. Tuberculous synovitis is important differencial diagnosis in patients with arthropathies and risk factors for TB in all the countries and all patients' ages even when tuberculin skin test is negative

Rapidly Rotating Fermi Gases

We show that the density profile of a Fermi gas in rapidly rotating potential will develop prominent features reflecting the underlying Landau level like energy spectrum. Depending on the aspect ratio of the trap, these features can be a sequence of ellipsoidal volumes or a sequence of quantized steps.Comment: 4 pages, 1 postscript fil

Quantum Phase Transition of Spin-2 Cold Bosons in an Optical Lattice

The Bose-Hubbard Hamiltonian of spin-2 cold bosons with repulsive interaction in an optical lattice is proposed. After neglecting the hopping term, the site-independent Hamiltonian and its energy eigenvalues and eigenstates are obtained. We consider the hopping term as a perturbation to do the calculations in second order and draw the phase diagrams for different cases. The phase diagrams show that there is a phase transition from Mott insulator with integer number bosons to superfluid when the ratio $c_0/t$ ($c_0$ is the spin-independent on-site interaction and $t$ the hopping matrix element between adjacent lattice sites) is decreased to a critical value and that there is different phase boundary between superfluid and Mott insulator phase for different Zeeman level component in some ground states. We find that the position of phase boundary for different Zeeman level component is related to its average population in the Mott ground state.Comment: 16 pages, 6 figure

Histological and immunohistochemical evaluation of mandibular bone tissue regeneration

The purpose of the study was to perform an immunohistochemical and histological evaluation of samples taken from different bone regeneration procedures in atrophic human mandible. 30 patients (15 men and 15 women, age range of 35-60 years), non-smokers, with good general and oral health were recruited in this study and divided into three groups. The first group included patients who were treated with blood Concentration Growth Factors (bCGF), the second group included patients who were treated with a mixture of bCGF and autologous bone, while the third group of patients was treated with bCGF and tricalcium phosphate/hydroxyapatite (TCP-HA). Six months after the regenerative procedures, all patients undergone implant surgery, and a bone biopsy was carried out in the site of implant insertion. Each sample was histologically and immunohistochemically examined. Histological evaluation showed a complete bone formation for group II, partial ossification for group I, and moderate ossification for group III. Immunohistochemical analysis demonstrated a statistically significant difference between the three groups, and the best clinical result was obtained with a mixture of bCGF and autologous bone

HPTLC assay of nicotine and cotinine in biological samples

This study presents the development of a simple high-performance thin layer chromatography (HPTLC) method for the determination of nicotine and its metabolite cotinine in human plasma and urine. The following mobile phases: methanol: ammonia (100:1.5, v:v), chloroform: acetone: ammonia (48.75: 48.75: 2.5, v:v:v), methanol: chloroform: ammonia (48.75: 48.75: 0.5, v:v:v) and glass plates precoated with silicagel 60 F254 (20x20) as a stationary phase were used. Densitometric scanning was performed at 263 nm. Two different extraction procedures have been applied: liquid-liquid extraction using dichloromethane at alkaline pH and solid-phase extraction using C18 cartridges. Preliminary tests in order to establish the system of solvents for development, as well as the range of linearity, were conducted. The best separation of nicotine and cotinine was obtained by using methanol: chloroform: ammonia (48.75: 48.75: 0.5, v:v:v) as the mobile phase. The liquid-liquid extraction technique led to better results than solid phase extraction. The regression curves were linear (with a corresponding correlation coefficient higher than 0.99) in the quantities range of 200 ng–1000 ng/spot for both nicotine and cotinine. The UV spectra confirm the identification of nicotine and cotinine both in the standards and in the extracts after liquid-liquid extraction. The proposed method can be applied for the simultaneous evaluation of nicotine and cotinine in biological samples at toxic/lethal levels. Thus, the method may be applicable in lethal nicotine intoxication cases in forensic toxicological analysis

Topological defects in spinor condensates

We investigate the structure of topological defects in the ground states of spinor Bose-Einstein condensates with spin F=1 or F=2. The type and number of defects are determined by calculating the first and second homotopy groups of the order-parameter space. The order-parameter space is identified with a set of degenerate ground state spinors. Because the structure of the ground state depends on whether or not there is an external magnetic field applied to the system, defects are sensitive to the magnetic field. We study both cases and find that the defects in zero and non-zero field are different.Comment: 10 pages, 1 figure. Published versio

Multiscale Bone Remodelling with Spatial P Systems

Many biological phenomena are inherently multiscale, i.e. they are characterized by interactions involving different spatial and temporal scales simultaneously. Though several approaches have been proposed to provide "multilayer" models, only Complex Automata, derived from Cellular Automata, naturally embed spatial information and realize multiscaling with well-established inter-scale integration schemas. Spatial P systems, a variant of P systems in which a more geometric concept of space has been added, have several characteristics in common with Cellular Automata. We propose such a formalism as a basis to rephrase the Complex Automata multiscaling approach and, in this perspective, provide a 2-scale Spatial P system describing bone remodelling. The proposed model not only results to be highly faithful and expressive in a multiscale scenario, but also highlights the need of a deep and formal expressiveness study involving Complex Automata, Spatial P systems and other promising multiscale approaches, such as our shape-based one already resulted to be highly faithful.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005