918 research outputs found

    Critical behavior of 3D Z(N) lattice gauge theories at zero temperature

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    Three-dimensional Z(N)Z(N) lattice gauge theories at zero temperature are studied for various values of NN. Using a modified phenomenological renormalization group, we explore the critical behavior of the generalized Z(N)Z(N) model for N=2,3,4,5,6,8N=2,3,4,5,6,8. Numerical computations are used to simulate vector models for N=2,3,4,5,6,8,13,20N=2,3,4,5,6,8,13,20 for lattices with linear extension up to L=96L=96. We locate the critical points of phase transitions and establish their scaling with NN. The values of the critical indices indicate that the models with N>4N>4 belong to the universality class of the three-dimensional XYXY model. However, the exponent α\alpha derived from the heat capacity is consistent with the Ising universality class. We discuss a possible resolution of this puzzle. We also demonstrate the existence of a rotationally symmetric region within the ordered phase for all N≄5N\geq 5 at least in the finite volume.Comment: 25 pages, 4 figures, 8 table

    The phase transitions in 2D Z(N) vector models for N>4

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    We investigate both analytically and numerically the renormalization group equations in 2D Z(N) vector models. The position of the critical points of the two phase transitions for N>4 is established and the critical index \nu\ is computed. For N=7, 17 the critical points are located by Monte Carlo simulations and some of the corresponding critical indices are determined. The behavior of the helicity modulus is studied for N=5, 7, 17. Using these and other available Monte Carlo data we discuss the scaling of the critical points with N and some other open theoretical problems.Comment: 19 pages, 8 figures, 10 tables; version to appear on Phys. Rev.

    Evaluation of the Efficacy and Safety of a Compound of Micronized Flavonoids in Combination With Vitamin C and Extracts of Centella asiatica, Vaccinium myrtillus, and Vitis vinifera for the Reduction of Hemorrhoidal Symptoms in Patients With Grade II and III Hemorrhoidal Disease: A Retrospective Real-Life Study

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    Background and Aim: Several evidences have shown how, in hemorrhoidal disease, phlebotonic flavonoid agents such as quercetin reduce capillary permeability by increasing vascular walls resistance, how rutin and vitamin C have antioxidant properties, and that Centella asiatica has reparative properties towards the connective tissue. A retrospective study was designed in order to evaluate the efficacy and safety of a compound consisting of micronized flavonoids in combination with vitamin C and extracts of C. asiatica, Vaccinium myrtillus, and Vitis vinifera for grade II and III hemorrhoidal disease. Patients and Methods: Data of 49 patients, over 18, who were following a free diet regimen, not on therapy with other anti-hemorrhoid agents, treated with a compound consisting of 450 mg of micronized diosmin, 300 mg of C. asiatica, 270 mg of micronized hesperidin, 200 mg of V. vinifera, 160 mg of vitamin C, 160 mg of V. myrtillus, 140 mg of micronized quercetin, and 130 mg of micronized rutin (1 sachet or 2 tablets a day) for 7 days were collected. Hemorrhoid grade according to Goligher’s scale together with anorectal symptoms (edema, prolapse, itching, thrombosis, burning, pain, tenesmus, and bleeding) both before treatment (T0) and after 7 days of therapy (T7) were collected. Primary outcomes were the reduction of at least one degree of hemorrhoids according to Goligher’s scale assessed by proctological examination and compound safety. The secondary outcome was the reduction of anorectal symptoms assessed by questionnaires administered to patients. Results: Forty-four patients (89.8%) presented a reduction in hemorrhoidal grade of at least one grade (p < 0.001). No adverse events with the use of the compound were noted. A significant reduction was observed in all anorectal symptoms evaluated (p < 0.05). No predictors of response to the compound were identified among the clinical and demographic variables collected. Conclusion: The compound analyzed was effective and safe for patients with grade II and III hemorrhoidal disease according to Goligher’s scale

    Mecanismos de transferĂȘncia de massa na desidratação osmĂłtica de goiaba em soluçÔes de sacarose, sucralose e açĂșcar invertido.

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    O objetivo deste trabalho foi avaliar o efeito da concentração de soluçÔes de sacarose, sucralose e açĂșcar invertido sobre a cinĂ©tica da desidratação osmĂłtica de pedaços de goiaba. FraçÔes de 1/12 do fruto foram imersas em soluçÔes de sacarose a 0,5 e 0,4 g mL-1, de sacarose a 0,3 g mL-1 + sucralose a 0,2 g L-1 e em xarope de açĂșcar invertido, a 50 ÂșC, por 2 h, sob agitação de 60 min. A solução de açĂșcar invertido promoveu maior perda de ĂĄgua e redução de massa nas amostras de goiaba submetidas Ă  desidratação osmĂłtica. O melhor desempenho foi obtido para o tratamento em solução de sacarose a 0,4 g mL-1, com perda de ĂĄgua e redução de massa semelhantes aos valores obtidos na imersĂŁo em solução de sacarose a 0,5 g mL-1 e ganho de sĂłlidos similar ao observado em solução de sacarose a 0,3 g mL-1

    Oral microbiota and salivary levels of oral pathogens in gastro‐intestinal diseases: Current knowledge and exploratory study

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    Various bi‐directional associations exist between oral health and gastro‐intestinal diseases. The oral microbiome plays a role in the gastro‐intestinal carcinogenesis and fusobacteria are the most investigated bacteria involved. This paper aims to review the current knowledge and report the preliminary data on salivary levels of Fusobacterium nucleatum, Porphyromonas gingivalis and Candida albicans in subjects with different gastro‐intestinal conditions or pathologies, in order to determine any differences. The null hypothesis was “subjects with different gastro‐intestinal diseases do not show significant differences in the composition of the oral microbiota”. Twenty‐one subjects undergoing esophagastroduodenoscopy or colonscopy were recruited. For each subject, a salivary sample was collected before the endoscopy procedure, immediately stored at ‐20°C and subsequently used for genomic bacterial DNA extraction by real‐time PCR. Low levels of F. nucleatum and P. gingivalis were peculiar in the oral microbiota in subjects affected by Helicobater pylori‐negative chronic gastritis without cancerization and future studies will elucidate this association. The level of C. albicans did not statistically differ among groups. This preliminary study could be used in the future, following further investigation, as a non‐invasive method for the search of gastrointestinal diseases and associated markers

    Sulodexide counteracts endothelial dysfunction induced by metabolic or non-metabolic stresses through activation of the autophagic program

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    OBJECTIVE: Endothelial dysfunction (ED) predisposes to venous thrombosis (VT) and post-thrombotic syndrome (PTS), a long-term VT-related complication. Sulodexide (SDX) is a highly purified glycosaminoglycan with antithrombotic, pro-fibrinolytic and anti-inflammatory activity used in the treatment of chronic venous disease (CVD), including patients with PTS. SDX has recently obtained clinical evidence in the “extension therapy” after initial-standard anticoagulant treatment for the secondary prevention of recurrent deep vein thrombosis (DVT). Herein, we investigated how SDX counteracts ED. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVEC) were used. Metabolic and non metabolic-induced ED was induced by treating with methylglyoxal (MGO) or irradiation (IR), respectively. Bafilomycin A1 was used to inhibit autophagy. The production of reactive oxygen species (ROS), tetrazolium bromide (MTT) assay for cell viability, terminal de-oxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for cell apoptosis, Real-time PCR and Western blot analysis for gene and protein expression were used. RESULTS: SDX protected HUVEC from MGO- or IR-induced apoptosis by counteracting the activation of the intrinsic and extrinsic caspase cascades. The cytoprotective effects of SDX resulted from a reduction in a) ROS production, b) neo-synthesis and release of pro-inflammatory cytokines (TNFα, IL1, IL6, IL8), c) DNA damage induced by MGO or IR. These effects were reduced when autophagy was inhibited. CONCLUSIONS: Data herein collected indicate the ability of SDX to counteract ED induced by metabolic or non-metabolic stresses by involving the intracellular autophagy pathway. Our experience significantly increases the knowledge of the mechanisms of action of SDX against ED and supports the use of SDX in the treatment of CVD, PTS and in the secondary prevention of recurrent DVT
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