2,669 research outputs found

    Rapidly Rotating Fermi Gases

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    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

    Post's correspondence problem for hyperbolic and virtually nilpotent groups

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    Post's Correspondence Problem (the PCP) is a classical decision problem in theoretical computer science that asks whether for pairs of free monoid morphisms g,h ⁣:ΣΔg, h\colon\Sigma^*\to\Delta^* there exists any non-trivial xΣx\in\Sigma^* such that g(x)=h(x)g(x)=h(x). Post's Correspondence Problem for a group Γ\Gamma takes pairs of group homomorphisms g,h ⁣:F(Σ)Γg, h\colon F(\Sigma)\to \Gamma instead, and similarly asks whether there exists an xx such that g(x)=h(x)g(x)=h(x) holds for non-elementary reasons. The restrictions imposed on xx in order to get non-elementary solutions lead to several interpretations of the problem; we consider the natural restriction asking that xker(g)ker(h)x \notin \ker(g) \cap \ker(h) and prove that the resulting interpretation of the PCP is undecidable for arbitrary hyperbolic Γ\Gamma, but decidable when Γ\Gamma is virtually nilpotent. We also study this problem for group constructions such as subgroups, direct products and finite extensions. This problem is equivalent to an interpretation due to Myasnikov, Nikolev and Ushakov when one map is injective.Comment: 17 page

    HPTLC assay of nicotine and cotinine in biological samples

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    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

    Rapid communication: Mapping of the Ca2+ ATPase of fast twitch 1 skeletal muscle sarcoplasmic reticulum (ATP2A1) gene to porcine chromosome 3

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    Locus Name. Ca2+ ATPase of fast twitch 1 skeletal muscle sarcoplasmic reticulum. Species. Sus scrofa. Locus Symbol. ATP2A1. Source of Primers. Two sets of PCR primers were designed based on human ATP2A1 sequences (Gen- Bank accession numbers U96773 and U96777) available in the GenBank database. Using pig genomic DNA as a template we used set A primers to amplify approximately 1,100 bp spanning exon 1 to exon 2 and set B primers to amplify 1,200 bp gene segment covering some of exon 8 through part of exon 9. These sequences were deposited in GenBank, accession number AY027797-AY027799

    Histological and immunohistochemical evaluation of mandibular bone tissue regeneration

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    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
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