Sonochemical route for mesoporous silica-coated magnetic nanoparticles towards pH-triggered drug delivery system

This work reports a pH-triggered release system based on core@shell mesoporous magnetic nanoparticles (MNP@mSiO2) obtained using a simple and rapid ultrasound-assisted method. Performed characterization reveals magnetic cores of Fe2.9Mn0.1O4 (38 ± 6 nm) and specific loss power values adequate for hyperthermia (463 W/g), surrounded by a mesoporous silica shell (10 ± 2 nm) with large surface area (269 m2 g-1) functionalized with hydroxyl groups (-OH). MNP@mSiO2 were loaded with DOX and amino-silane grops, providing pH-triggered DOX release at acidic environments, driving by dipolar intermolecular interactions. The experimental DOX release kinetics at pH 5.5, 6.6 and 7.4 were determined and adjusted to Gompertz dissolution model (Nash–Sutcliffe efficiency coefficient (NSE>0.9)), where the only strongly pH-dependent variable is the percentage of DOX released. The pH-triggered response observed in the system was ~20% of the DOX loaded into the MNP@mSiO2 is released at pH 6.6 or 7.4, whereas up to 80 wt% is released at pH 5.5. Time to 50% of release and dissociation rate of the system remaining constant, suggesting no-pH influence on these parameters. The biological assays highlight negligible hemolytic effect and cytocompatibility of the hybrid material, pointing out the potential use of MNP@mSiO2 as a magnetic driven drug delivery system with pH-triggered drug release kinetics at acidic environments. These results probe the feasibility of sonochemical methods in the elaboration of biocompatible and controlled properties nanomaterials for drug release applications, with the advantage of accurately responses predictions by mathematical model and using minimal processing steps or laboratory equipment. © 2021 The Author

Electromagnetic form factors of light vector mesons

The electromagnetic form factors G_E(q^2), G_M(q^2), and G_Q(q^2), charge radii, magnetic and quadrupole moments, and decay widths of the light vector mesons rho^+, K^{*+} and K^{*0} are calculated in a Lorentz-covariant, Dyson-Schwinger equation based model using algebraic quark propagators that incorporate confinement, asymptotic freedom, and dynamical chiral symmetry breaking, and vector meson Bethe-Salpeter amplitudes closely related to the pseudoscalar amplitudes obtained from phenomenological studies of pi and K mesons. Calculated static properties of vector mesons include the charge radii and magnetic moments: r_{rho+} = 0.61 fm, r_{K*+} = 0.54 fm, and r^2_{K*0} = -0.048 fm^2; mu_{rho+} = 2.69, mu_{K*+} = 2.37, and mu_{K*0} = -0.40. The calculated static limits of the rho-meson form factors are similar to those obtained from light-front quantum mechanical calculations, but begin to differ above q^2 = 1 GeV^2 due to the dynamical evolution of the quark propagators in our approach.Comment: 8 pages of RevTeX, 5 eps figure

Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon

It is shown that the Quark-Level Linear $\sigma$ Model (QLL$\sigma$M) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with the experimental data. The bare mass of the $\sigma$ meson is predicted to be $m_\sigma=666$ MeV and the two-photon width $\Gamma(\sigma\to\gamma\gamma)=(2.6\pm 0.3)$ keV. It is argued that the mass predicted by the QLL$\sigma$M corresponds to the $\gamma\gamma\to\sigma\to NN$ reaction, i.e. to a $t$-channel pole of the $\gamma N\to N\gamma$ reaction. Large -angle Compton scattering experiments revealing effects of the $\sigma$ meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of strong interaction while being part of the constituent quark.Comment: 17 pages, 6 figure

Implante transcateter valve‐in‐valve para disfunção de biopróteses cirúrgicas aórticas

RESUMOIntroduçãoEstudos recentes têm demonstrado a eficácia do implante transcateter valve‐in‐valve para o tratamento de disfunção de biopróteses em pacientes de alto risco cirúrgico. Apresentamos nossa experiência inicial com o implante valve‐in‐valve.MétodosCaracterizamos o perfil clínico, ecocardiográfico e do procedimento, e reportamos os resultados de médio prazo de pacientes com disfunção de bioprótese submetidos a implante valve‐in‐valve em posição aórtica.ResultadosIncluímos sete pacientes do sexo masculino, com idade de 72,6 ± 10,0 anos. O escore STS foi 9,6 ± 10,5%, e o EuroSCORE logístico foi 22,7 ± 14,7%. Três pacientes apresentavam dupla disfunção; dois tinham insuficiência; e dois exibiam estenose isolada. A via transfemoral foi utilizada em seis casos, e a transapical, em um caso. Os dispositivos implantados incluíram as próteses Sapien XT (n = 5) e CoreValve (n = 2). O sucesso do procedimento foi obtido em seis (85,7%) casos. Após o procedimento, o gradiente médio reduziu‐se de 38,2 ± 9,6mmHg para 20,9 ± 5,9mmHg, e a área valvar elevou‐se de 1,2 ± 0,4cm2 para 1,5 ± 0,5cm2. Ao final de 1 ano, não ocorreram óbitos e nem outros desfechos adversos significativos; 80% dos pacientes encontravam‐se em classe funcional NYHA I/II. Os gradientes transvalvares e a área valvar permaneceram inalterados nesse período.ConclusõesO procedimento valve‐in‐valve foi eficaz na maioria dos pacientes de alto risco cirúrgico com disfunção de bioprótese. Quando realizado em pacientes bem selecionados, resulta em desfechos clínicos e hemodinâmicos satisfatórios.ABSTRACTBackgroundRecent studies have demonstrated the efficacy of the transcatheter valve‐in‐valve implantation for the treatment of bioprosthesis dysfunction in high‐risk surgical patients. This study presents the initial experience with valve‐in‐valve implantation.MethodsClinical, echocardiographic, and procedural profiles were characterized, and the mid‐term results of patients with surgical bioprosthesis dysfunction submitted to valve‐in‐valve implantation in the aortic position were reported.ResultsSeven male patients were included, aged 72.6 ± 10.0 years. The STS score was 9,6 ± 10,5%, and the logistic EuroSCORE was 22.7 ± 14.7%. Three patients had combined aortic bioprosthesis failure; two had isolated regurgitation; and two had isolated stenosis. The transfemoral access was used in six cases, and the transapical access in one case. Implanted devices included Sapien XT (n = 5) and CoreValve (n = 2) prostheses. Procedural success was achieved in six (85.7%) cases. After the procedure, the mean gradient decreased from 38.2 ± 9.6mmHg to 20.9 ± 5.9mmHg, and the valve area increased from 1.2 ± 0.4cm2 to 1.5 ± 0.5cm2. After 1 year, there were no deaths and no other significant adverse outcomes; 80% of patients were in NYHA functional class I/II. The transvalvular gradients and valve area remained unchanged in this period.ConclusionsThe valve‐in‐valve procedure was effective in most high‐risk surgical patients with bioprosthesis dysfunction. When performed in well‐selected patients, it results in satisfactory clinical and hemodynamic outcomes

Fundamental Superstrings as Holograms

The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz light-cone gauge is viewed as a possible boundary hologram of the near horizon region of a small black string. For toroidally compactified strings, the hologram has global symmetries of AdS_3 \times S^{d-1} \times T^{8-d}, (d =3,..,8), only some of which extend to local conformal symmetries. We construct the bulk string theory in detail for the particular case of d=3. The symmetries of the hologram are correctly reproduced from this exact worldsheet description in the bulk. Moreover, the central charge of the boundary Virasoro algebra obtained from the bulk agrees with the Wald entropy of the associated small black holes. This construction provides an exact CFT description of the near horizon region of small black holes both in Type-II and heterotic string theory arising from multiply wound fundamental superstrings.Comment: 46 pages, JHEP style. v2: Comments, references adde

Plantio direto, adubação verde e suplementação com esterco de aves na produção orgânica de berinjela.

Sob manejo orgânico, foram avaliados, em Seropédica, RJ, os sistemas de plantio direto da berinjela(Solanum melongena) nas palhadas de Crotalaria juncea (crotalária), Pennisetum glaucum (milheto, cv. BRS 1501)e vegetação espontânea (pousio), em comparação com o plantio convencional (aração e gradagem ou enxada rotativa). Simultaneamente, foram avaliados três tipos de cultivo: berinjela em monocultura, em consórcio com crotalária e em consórcio com caupi (Vigna unguiculata, cv. Mauá). Não houve diferença entre os sistemas de plantio direto e convencional quanto à produção comercial da berinjela. A palhada da crotalária foi mais eficiente que a do milheto e do pousio para cobertura morta do solo e conseqüentemente o controle de plantas espontâneas foi maior. O cultivo simultâneo com as leguminosas não acarretou redução da produtividade da berinjela.Em um segundo estudo, foram comparados plantio direto (palhadas de crotalária e da vegetação espontânea) e plantio convencional, combinados com doses crescentes de cama de aviário (0, 100, 200 e 400 kg ha-1 de N)aplicada em cobertura. Em termos de aporte de biomassa, a crotalária foi novamente superior à vegetação espontânea.A berinjela respondeu à adubação orgânica, com produtividade máxima de 50,6 t ha-1 , correspondendo à maior dose empregada, contra 36,9 t ha-1 referentes ao controle

New constraints on protostellar jet collimation from high-density gas UV tracers

The analysis of high-resolution profiles of the semiforbidden UV lines of C III](1908) and Si III](1892) in the spectra of T Tauri stars (TTSs) shows the following : (1) There is C III](1908) and Si III](1892) emission at velocities that are similar to those observed in the optical forbidden lines formed in the TTSs jets. The luminosity of the UV lines is comparable to that of the optical lines. (2) The comparison between the optical and UV light curves indicates that the C III](1908) and Si III](1892) emission of RY Tau is not associated with accretion shocks, but it is produced farther than 2 R-* from the star. (3) The profiles of the UV semiforbidden lines are significantly broader than those of the optical forbidden lines. These profiles cannot be produced in a narrow collimated beam, and they are most likely produced in a bow-shaped shock wave formed at the base of the optical jet, where the hot gas emits in a broad range of projected radial velocities. (4) The atmosphere of RU Lup contributes significantly to the Si III](1892) emission. (5) A puzzling narrow feature is observed close to the C III](1908) line. The feature is blueshifted by -260 km s(-1), which corresponds to the wind terminal velocity measured in the P Cygni profile of the Mg II (UV1) lines. Moreover, constraints are derived on the characteristics of the C III](1908) and Si III](1892) emitting region in RY Tau. It is shown that 4.7 less than or equal to log T-e less than or equal to 5.0 and 10(9) cm(-3) less than or equal to N-e less than or equal to 10(11) cm(-3) provided that the emission is produced in a collisional plasma and that the 1665 Angstrom feature observed in low-dispersion International Ultraviolet Explorer (IUE) spectra is confirmed to be O III](1665) emission produced in the wind. These very high densities are difficult to generate in the shocks produced by the magnetic pinching of centrifugally driven magnetized disk winds. The data also suggest that the shocked layer has a radius of some few stellar radii and it is closer than similar to 38 R-* to the star

Soil organisms in organic and conventional cropping systems.

Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas

Approximate solution of the Duffin-Kemmer-Petiau equation for a vector Yukawa potential with arbitrary total angular momenta

The usual approximation scheme is used to study the solution of the Duffin-Kemmer-Petiau (DKP) equation for a vector Yukawa potential in the framework of the parametric Nikiforov-Uvarov (NU) method. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for arbitrary total angular momentum in closed form. Further, the approximate energy equation and wave function spinor components are also given for case. A set of parameter values is used to obtain the numerical values for the energy states with various values of quantum levelsComment: 17 pages; Communications in Theoretical Physics (2012). arXiv admin note: substantial text overlap with arXiv:1205.0938, and with arXiv:quant-ph/0410159 by other author