22 research outputs found
Spectrum of confining strings in SU(N) gauge theories
We study the spectrum of the confining strings in four-dimensional SU(N)
gauge theories. We compute, for the SU(4) and SU(6) gauge theories formulated
on a lattice, the string tensions sigma_k related to sources with Z_N charge k,
using Monte Carlo simulations. Our results are consistent with the sine formula
sigma_k/sigma = sin k pi/N / sin pi/N for the ratio between sigma_k and the
standard string tension sigma.
For the SU(4) and SU(6) cases the accuracy is approximately 1% and 2%,
respectively. The sine formula is known to emerge in various realizations of
supersymmetric SU(N) gauge theories. On the other hand, our results show
deviations from Casimir scaling. We also discuss an analogous behavior
exhibited by two-dimensional SU(N) x SU(N) chiral models.Comment: Latex, 34 pages, 10 figures. Results of new SU(4) simulations added.
The new data are included in the analysis, leading to improved final
estimates for SU(4). Conclusions unchange
Color superconductivity, Z_N flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories
We study the Z_N flux tubes and monopole confinement in deformed N=2* super
Yang-Mills theories. In order to do that we consider an N=4 super Yang-Mills
theory with an arbitrary gauge group G and add some N=2, N=1 and N=0
deformation terms. We analyze some possible vacuum solutions and phases of the
theory, depending on the deformation terms which are added. In the Coulomb
phase for the N=2* theory, G is broken to U(1)^r and the theory has monopole
solutions. Then, by adding some deformation terms, the theory passes to the
Higgs or color superconducting phase, in which G is broken to its center C_G.
In this phase we construct the Z_N flux tubes ansatz and obtain the BPS string
tension. We show that the monopole magnetic fluxes are linear integer
combinations of the string fluxes and therefore the monopoles can become
confined. Then, we obtain a bound for the threshold length of the
string-breaking. We also show the possible formation of a confining system with
3 different monopoles for the SU(3) gauge group. Finally we show that the BPS
string tensions of the theory satisfy the Casimir scaling law.Comment: 18 pages, 2 figures, typo corrections. Version to appear in Phys.
Rev.
Memory retrieval improvement by Heteropterys aphrodisiaca in aging rats
Few data exists about the pharmacological properties of Heteropterys aphrodisiaca O. Mach. (Malpighiaceae), which is native to the scrubland regions of Brazil. The present study investigated the effects of oral treatment with H. aphrodisiaca extract (BST0298) on the learning and memory of young (3-6 months) and aged (21-23 months) rats, and compared the in vitro antioxidant activity of three lots collected in different years. An improvement in the number of sessions to learn the task was observed in the left/right discrimination test in aged rats treated for 45 days with 25 mg/kg (7.0 ± 0.5; p=0.005) or 50 mg/kg (7.6 ± 0.6; p=0.012) compared with control old rats (11.0 ± 1.6). On the other hand, pre-treatment did not improve the performance of scopolamine-treated mice in the passive avoidance test. The in vitro malondialdehyde test showed that all three different extracts presented similar antioxidant activity. The flavonoids astilbin, isoastilbin and neoastilbin were isolated from the extract and may contribute to the biological activity. These results suggest that repeated treatment with H. aphrodisiaca improves learning and memory, probably by a non-muscarinic mechanism.Existem poucos dados disponíveis sobre as propriedades farmacológicas da Heteropterys aphrodisiaca O. Mach. (Malpighiaceae), nativa da região do pantanal brasileiro. O presente estudo investigou o efeito do tratamento oral com um extrato de H. aphrodisiaca (BST0298) sobre a memória e aprendizagem de ratos jovens (3-6 meses) e idosos (21-23 meses) e comparou a atividade antioxidante in vitro de três lotes, coletados em diferentes anos. Melhora quanto ao número de sessões necessárias para aprender a tarefa foi observada no teste de discriminação direita/esquerda em ratos idosos tratados por 45 dias com doses de 25 mg/kg (7,0 ± 0,5; p=0,005) e 50 mg/kg (7,6 ± 0,6; p=0,012) comparados com ratos idosos controle (11,0 ± 1,6). Por outro lado, o pré-tratamento com o extrato não melhorou o desempenho de camundongos tratados com escopolamina no teste da esquiva passiva. Em relação à avaliação da atividade antioxidante in vitro pelo teste do malonodialdeído, os três lotes analisados apresentaram atividade antioxidante semelhante. Os flavonóides astilbina, isoastilbina e neoastilbina foram isolados do extrato e podem contribuir para a atividade biológica. Estes resultados sugerem que a administração repetida de H. aphrodisiaca melhora a memória e aprendizagem provavelmente por um mecanismo não muscarínico
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Collagen-infilled 3D printed scaffolds loaded with miR-148b-transfected bone marrow stem cells improve calvarial bone regeneration in rats
Differentiation of progenitors in a controlled environment improves the repair of critical-sized calvarial bone defects; however, integrating micro RNA (miRNA) therapy with 3D printed scaffolds still remains a challenge for craniofacial reconstruction. In this study, we aimed to engineer three-dimensional (3D) printed hybrid scaffolds as a new ex situ miR-148b expressing delivery system for osteogenic induction of rat bone marrow stem cells (rBMSCs) in vitro, and also in vivo in critical-sized rat calvarial defects. miR-148b-transfected rBMSCs underwent early differentiation in collagen-infilled 3D printed hybrid scaffolds, expressing significant levels of osteogenic markers compared to non-transfected rBMSCs, as confirmed by gene expression and immunohistochemical staining. Furthermore, after eight weeks of implantation, micro-computed tomography, histology and immunohistochemical staining results indicated that scaffolds loaded with miR-148b-transfected rBMSCs improved bone regeneration considerably compared to the scaffolds loaded with non-transfected rBMSCs and facilitated near-complete repair of critical-sized calvarial defects. In conclusion, our results demonstrate that collagen-infilled 3D printed scaffolds serve as an effective system for miRNA transfected progenitor cells, which has a promising potential for stimulating osteogenesis and calvarial bone repair. © 2019 Elsevier B.V.National Science Foundation: 1600118 National Institutes of Health: RDE024790A Osteology Foundation: 15-042 BIDEP 2219 International Team for Implantology: 1275_2017 Türkiye Bilimsel ve Teknolojik Araştirma KurumuThis research was funded by Osteology Foundation ( 15-042 ), International Team for Implantology (1275_2017) , and National Science Foundation ( 1600118 ) and National Institutes of Health ( RDE024790A ). Dr. R. Seda Tigli Aydin acknowledges a grant provided by the Scientific and Technological Research Council of Turkey (TUBITAK) ( BIDEP 2219 ). The authors are also thankful to The Huck Institute of The Life Sciences and Materials Research Institute at the Pennsylvania State University in providing support for the core facility use
Role of Sonic hedgehog signaling and the expression of its components in human embryonic stem cells
10.1016/j.scr.2009.09.002Stem Cell Research4138-4