Universal properties of the U(1) current at deconfined quantum critical points: comparison with predictions from gauge/gravity duality

The deconfined quantum critical point of a two-dimensional SU(N) antiferromagnet is governed by an Abelian Higgs model in $d=2+1$ spacetime dimensions featuring $N$ complex scalar fields. In this context, we derive for $2\leq d\leq 4$ an exact formula for the central charge of the U(1) current in terms of the gauge coupling at quantum criticality and compare it with the corresponding result obtained using gauge-gravity duality. There is a remarkable similarity precisely for $d=2+1$. In this case the amplitude of the current correlation function has the same form as predicted by the gauge-gravity duality. We also compare finite temperature results for the charge susceptibility in the large $N$ limit with the result predicted by the gauge-gravity duality. Our results suggest that condensed matter systems at quantum criticality may provide interesting quantitative tests of the gauge-gravity duality even in absence of supersymmetry.Comment: 4.5 pages, 1 figure; v2: accepted in PRD, text restructured to make presentation/discussion clearer, references adde

Site-selective protein modification via disulfide rebridging for fast tetrazine/trans-cyclooctene bioconjugation

An inverse electron demand Diels–Alder reaction between tetrazine and trans-cyclooctene (TCO) holds great promise for protein modification and manipulation. Herein, we report the design and synthesis of a tetrazine-based disulfide rebridging reagent, which allows the site-selective installation of a tetrazine group into disulfide-containing peptides and proteins such as the hormone somatostatin (SST) and the antigen binding fragment (Fab) of human immunoglobulin G (IgG). The fast and efficient conjugation of the tetrazine modified proteins with three different TCO-containing substrates to form a set of bioconjugates in a site-selective manner was successfully demonstrated for the first time. Homogeneous, well-defined bioconjugates were obtained underlining the great potential of our method for fast bioconjugation in emerging protein therapeutics. The formed bioconjugates were stable against glutathione and in serum, and they maintained their secondary structure. With this work, we broaden the scope of tetrazine chemistry for site-selective protein modification to prepare well-defined SST and Fab conjugates with preserved structures and good stability under biologically relevant conditions

Evaluation of erythrocyte filtrability and its relation to globular membrane (Na+, K+)--dependent ATPase in hypertensive patients

The values of erythrocyte filtration index and erythrocyte membrane (Na+, K+) – dependent ATPase activity were evaluated in 21 hypertensive patients (12 men and 9 women) aged 46.3 ± 9.7 years. The patients suffered from essential hypertension and the blood pressure values recorded were 171.9 ± 21.3 mmHg systolic and 110.6 ± 12.2 mmHg diastolic. The activity of erythrocyte membrane Na+, K+ ATPase is significantly lower (p < 0.001) among the patients (0.074 ± 0.029 μmoles Pi/mg prot/h) than in the healthy controls (0.160 ± 0.045 μmoles Pi/mg prot/h). The rate of erythrocyte filtrability was also significantly lower (p < 0.001) in respect to the controls (12.84 ± 2.40 μl. seg.-1 and (15.80 ± 1.75, respectively). However, no correlation was found between the two parameters evaluated.This study was supported by a grant from INIC (MbL2)

The emergence of <i>Pax7</i>-expressing muscle stem cells during vertebrate head muscle development

Pax7 expressing muscle stem cells accompany all skeletal muscles in the body and in healthy individuals, efficiently repair muscle after injury. Currently, the in vitro manipulation and culture of these cells is still in its infancy, yet muscle stem cells may be the most promising route towards the therapy of muscle diseases such as muscular dystrophies.It is often overlooked that muscular dystrophies affect head and body skeletal muscle differently. Moreover, these muscles develop differently. Specifically, head muscle and its stem cells develop from the non-somitic head mesoderm which also has cardiac competence. To which extent head muscle stem cells retain properties of the early head mesoderm and might even be able to switch between a skeletal muscle and cardiac fate is not known. This is due to the fact that the timing and mechanisms underlying head muscle stem cell development are still obscure. Consequently, it is not clear at which time point one should compare the properties of head mesodermal cells and head muscle stem cells.To shed light on this, we traced the emergence of head muscle stem cells in the key vertebrate models for myogenesis, chicken, mouse, frog and zebrafish, using Pax7 as key marker. Our study reveals a common theme of head muscle stem cell development that is quite different from the trunk. Unlike trunk muscle stem cells, head muscle stem cells do not have a previous history of Pax7 expression, instead Pax7 expression emerges de-novo. The cells develop late, and well after the head mesoderm has committed to myogenesis. We propose that this unique mechanism of muscle stem cell development is a legacy of the evolutionary history of the chordate head mesoderm

Microviscosity of erythrocyte membrane in hypertensive patients

Twenty eight ambulatory patients (16 men and 12 women), suffering from essential hypertension, whose ages averaged 46.9 ± 9.6 years, were studied; the patients presented blood pressure values of 174.0 ± 22.7 mmHg systolic and 110.5 ± 11.7 mmHg diastolic. It was detected a significant rise of erythrocyte membrane microviscosity (p < 0.01) and a significant decrease of erythrocyte filtrability (p < 0.001). However, no significant correlation was observed between these two parameters. The results obtained suggest that essential hypertension induces or may be associated to intrinsic abnormalities of erythrocyte membrane eventually acting on globular flexibility

A pesquisa em fixação biológica do nitrogênio na Embrapa Soja: passado, presente e perspectivas futuras.

O passado. O presente. Pensado em sistemas agrícolas. Economia em fertilizantes e divisas. O futuro

On the Integrability and Chaos of an N=2 Maxwell-Chern-Simons-Higgs Mechanical Model

We apply different integrability analysis procedures to a reduced (spatially homogeneous) mechanical system derived from an off-shell non-minimally coupled N=2 Maxwell-Chern-Simons-Higgs model that presents BPS topological vortex excitations, numerically obtained with an ansatz adopted in a special - critical coupling - parametric regime. As a counterpart of the regularity associated to the static soliton-like solution, we investigate the possibility of chaotic dynamics in the evolution of the spatially homogeneous reduced system, descendant from the full N=2 model under consideration. The originally rich content of symmetries and interactions, N=2 susy and non-minimal coupling, singles out the proposed model as an interesting framework for the investigation of the role played by (super-)symmetries and parametric domains in the triggering/control of chaotic behavior in gauge systems. After writing down effective Lagrangian and Hamiltonian functions, and establishing the corresponding canonical Hamilton equations, we apply global integrability Noether point symmetries and Painleveproperty criteria to both the general and the critical coupling regimes. As a non-integrable character is detected by the pair of analytical criteria applied, we perform suitable numerical simulations, as we seek for chaotic patterns in the system evolution. Finally, we present some Comments on the results and perspectives for further investigations and forthcoming communications.Comment: 18 pages, 5 figure