2,271 research outputs found

    Mechanisms driving alteration of the Landau state in the vicinity of a second-order phase transition

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    The rearrangement of the Fermi surface of a homogeneous Fermi system upon approach to a second-order phase transition is studied at zero temperature. The analysis begins with an investigation of solutions of the equation ϵ(p)=μ\epsilon(p)=\mu, a condition that ordinarily has the Fermi momentum pFp_F as a single root. The emergence of a bifurcation point in this equation is found to trigger a qualitative alteration of the Landau state, well before the collapse of the collective degree of freedom that is responsible for the second-order transition. The competition between mechanisms that drive rearrangement of the Landau quasiparticle distribution is explored, taking into account the feedback of the rearrangement on the spectrum of critical fluctuations. It is demonstrated that the transformation of the Landau state to a new ground state may be viewed as a first-order phase transition.Comment: 16 pages, 10 figure

    N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine, a new cholinesterase and monoamine oxidase dual inhibitor

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    On the basis of N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)-N-methylprop-2-yn-1-amine (II, ASS234) and QSAR predictions, in this work we have designed, synthesized, and evaluated a number of new indole derivatives from which we have identified N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine (2, MBA236) as a new cholinesterase and monoamine oxidase dual inhibitor.PostprintPostprintPeer reviewe

    OCURRENCIA DE ÁCAROS Y CIGARRITA VERDE (HEMIPTERA, CICADELLIDAE) EN EL CULTIVO DEL PIÑON MANSO (Jatropha curcas L.) EN LAS LOCALIDADES DE SAN LORENZO, SAN ROQUE GONZÁLEZ. Y CAACUPÉ-PARAGUAY

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    La ocurrencia de ácaros y cigarrita verde, fue estudiada en el periodo de marzo a junio de 2009, en el cultivo del Piñón Manso (Jatropha curcas L.) en las localidades de San Lorenzo, San Roque González y Caacupé de la Republica del Paraguay. Las observaciones fueron realizadas semanalmente, en veinte plantas,las cuales fueron divididas en dos estratos (superior y medio), observando tres hojas por estrato, en total seis hojas por planta, considerando los ácaros adultos y ninfas móviles para el caso de la cigarrita. Durante las observaciones fueron detectadas cuatro especies de ácaros y una especie de cigarrita, ácaro blanco (Polyphagotarsonemus latus), ácaro de los cítricos (Panonychus spp), ácaro predador blanco (Amblyseius spp), ácaro predador rojo (Phytoseiulus spp.) y Cigarrita verde (Empoasca spp.). La intensidad de infestación en cada localidad y estrato de la planta fue variable. En general, se presentaron las mayores poblaciones de P.latusy Empoasca spp. en San Roque González,Panonychusspp. en San Lorenzo y Amblyseius spp. en Caacupé

    A basis for variational calculations in d dimensions

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    In this paper we derive expressions for matrix elements (\phi_i,H\phi_j) for the Hamiltonian H=-\Delta+\sum_q a(q)r^q in d > 1 dimensions. The basis functions in each angular momentum subspace are of the form phi_i(r)=r^{i+1+(t-d)/2}e^{-r^p/2}, i >= 0, p > 0, t > 0. The matrix elements are given in terms of the Gamma function for all d. The significance of the parameters t and p and scale s are discussed. Applications to a variety of potentials are presented, including potentials with singular repulsive terms of the form b/r^a, a,b > 0, perturbed Coulomb potentials -D/r + B r + Ar^2, and potentials with weak repulsive terms, such as -g r^2 + r^4, g > 0.Comment: 22 page

    Neuroprotective fragment C of tetanus toxin modulates IL-6 in an ALS mouse model

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    Neuroinflammation plays a significant role in amyotrophic lateral sclerosis (ALS) pathology, leading to the development of therapies targeting inflammation in recent years. Our group has studied the tetanus toxin C-terminal fragment (TTC) as a therapeutic molecule, showing neuroprotective properties in the SOD1G93A mouse model. However, it is unknown whether TTC could have some effect on inflammation. The objective of this study was to assess the effect of TTC on the regulation of inflammatory mediators to elucidate its potential role in modulating inflammation occurring in ALS. After TTC treatment in SOD1G93A mice, levels of eotaxin-1, interleukin (IL)-2, IL-6 and macrophage inflammatory protein (MIP)-1 alpha (ff) and galectin-1 were analyzed by immunoassays in plasma samples, whilst protein expression of caspase-1, IL-1β, IL-6 and NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) was measured in the spinal cord, extensor digitorum longus (EDL) muscle and soleus (SOL) muscle. The results showed reduced levels of IL-6 in spinal cord, EDL and SOL in treated SOD1G93A mice. In addition, TTC showed a different role in the modulation of NLRP3 and caspase-1 depending on the tissue analyzed. In conclusion, our results suggest that TTC could have a potential anti-inflammatory effect by reducing IL-6 levels in tissues drastically affected by the disease. However, further research is needed to study more in depth the anti-inflammatory effect of TTC in ALS

    Effects of photoperiod on epididymal and sperm morphology in a wild rodent, the viscacha (Lagostomus maximus maximus)

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    The viscacha (Lagostomus maximus maximus) is a seasonal South American wild rodent. The adult males exhibit an annual reproductive cycle with periods of maximum and minimum gonadal activity. Four segments have been identified in the epididymis of this species: initial, caput, corpus, and cauda. The main objective of this work was to relate the seasonal morphological changes observed in the epididymal duct with the data from epididymal sperm during periods of activity and gonadal regression using light and scanning electron microscopy (SEM). Under light and electron microscopy, epididymal corpus and cauda showed marked seasonal variations in structural parameters and in the distribution of different cellular populations of epithelium. Initial and caput segments showed mild morphological variations between the two periods. Changes in epididymal sperm morphology were observed in the periods analyzed and an increased number of abnormal gametes were found during the regression period. During this period, anomalies were found mainly in the head, midpiece, and neck, while in the activity period, defects were found only in the head. Our results confirm that the morphological characteristics of the epididymal segments, as well as sperm morphology, undergo significant changes during the reproductive cycle of Lagostomus.Fil: Cruceño, A. M.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Cátedra de Histología; ArgentinaFil: De Rosas, J. C.. Consejo Nacional de Investigaciones Científicas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Foscolo, Mabel Rosa. Consejo Nacional de Investigaciones Científicas y Tecnicas. Centro Cientifico Tecnologico Mendoza. Instituto Histologia y Embriologia de Mendoza "Dr. M. Burgos"; ArgentinaFil: Chaves, E. M.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Cátedra de Histología; ArgentinaFil: Scardapane, L.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Cátedra de Histología; ArgentinaFil: Dominguez, S.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Cátedra de Histología; ArgentinaFil: Aguilera Merlo, C.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Cátedra de Histología; Argentin

    A Review of Penile Cancer

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    Cancer of the penis is a rare tumour in Europe and mainly affects the elderly patient population. The aim of this paper was to analyse and study the characteristics of this tumour, in our patient population. Materials and Methods. A retrospective study was conducted on penile tumours diagnosed and treated in the Urology Department of the Hospital Universitario La Paz, Madrid, in the last ten years. Results. A total of 34 patients were diagnosed and treated. The mean age at presentation was 71.27 years. The mean time between symptoms and the first consultation was 12.54 months with a median of 6 months. The most common form of presentation was balanoposthitis (32%) and the most common site in our series was the glans. Partial penectomy was performed in 22 cases, total amputation in 8, and local excision in 3. Discussion. Carcinoma of the penis is a pathology which mostly affects elderly patients; in our series, the highest incidence was observed in patients in the group aged 75–84 years. The most common histological type was epidermoid carcinoma in its various forms of presentation. We recorded a mortality of 23%. Conclusion. Penile carcinoma is a rare pathology which affects elderly persons and is diagnosed late

    Development of Tropical Spastic Paraparesis in Human T-Lymphotropic Virus Type 1 Carriers Is Influenced by Interleukin 28B Gene Polymorphisms

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    Producción CientíficaInterleukin 28B (IL28B) rs12979860 polymorphisms were examined in 41 individuals with human T-lymphotrophic virus type 1 (HTLV-1). The alleles CT/TT were more frequent in 12 individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis than in 29 asymptomatic carriers (80% vs 20%; P = .03), and median HTLV-1 proviral load was greater in CT/TT than CC carriers (P = .01). Thus, IL28B testing and closer follow-up of HTLV-1 asymptomatic CT/TT carriers is warranted.Fundación Investigación y Educación en Sida Grant (IES) FIS (CP05/00300)Red de Investigación en SIDA Grant (RIS, ISCIII-RETIC RD06/006)Proyecto europeo NEAT Grant (LSHP-CT-2006-037570
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