435 research outputs found
Synthesis and characterization of bis-acylhydrazone derivatives as tetradentate ligands and their dinuclear metal(II) complexes
Two novel bis-acylhydrazone where as 1,4-diacetylbenzene bis(4-hydroxy benzoyl hydrazone) H_2L^1 and 1,4-diacetylbenzene bis(4-nitrobenzoyl hydrazone) H_2L^2 ligands bearing two hydrazone side groups and their metal(II) complexes have been synthesized and characterized by ^1H-NMR^ 13 C-NMR, elemental analysis, FT-IR infrared spectra, magnetic susceptibility measurements and UV-vis electronic absorption spectra. The L_1H_2, L_2H_2) ligands were synthesized by reacting 4-hydroxybenzohydrazide and 4-nitrobenzohydrazide with 1,4-diacetylbenzene, respectively. The ligands H_2L^1, L_2H_2) react with metal(II) chlorides anhydrous to form polymeric dinuclear metal(II) complexes with general formula [(M_2(L_x)_2_n] with a metal to ligand ratio of 1:1 when [x = 1, 2; M = Ni(II), Co(II), Cu(II), Zn(II) and Cd(II)]. In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and nitro
groups of dihyrazone moiety do not participate in coordination
Energetic BEM for the numerical analysis of 2D Dirichlet damped wave propagation exterior problems
Abstract Time-dependent problems modeled by hyperbolic partial differential equations can be reformulated in terms of boundary integral equations and solved via the boundary element method. In this context, the analysis of damping phenomena that occur in many physics and engineering problems is a novelty. Starting from a recently developed energetic space-time weak formulation for 1D damped wave propagation problems rewritten in terms of boundary integral equations, we develop here an extension of the so-called energetic boundary element method for the 2D case. Several numerical benchmarks, whose numerical results confirm accuracy and stability of the proposed technique, already proved for the numerical treatment of undamped wave propagation problems in several dimensions and for the 1D damped case, are illustrated and discussed
Application of Energetic BEM to 2D Elastodynamic Soft Scattering Problems
Abstract
Starting from a recently developed energetic space-time weak formulation of the Boundary Integral Equations related to scalar wave propagation problems, in this paper we focus for the first time on the 2D elastodynamic extension of the above wave propagation analysis. In particular, we consider elastodynamic scattering problems by open arcs, with vanishing initial and Dirichlet boundary conditions and we assess the efficiency and accuracy of the proposed method, on the basis of numerical results obtained for benchmark problems having available analytical solution
Lubich convolution quadratures and their application to problems described by space-time BIEs
A study on spline quasi-interpolation based quadrature rules for the isogeometric Galerkin BEM
Two recently introduced quadrature schemes for weakly singular integrals
[Calabr\`o et al. J. Comput. Appl. Math. 2018] are investigated in the context
of boundary integral equations arising in the isogeometric formulation of
Galerkin Boundary Element Method (BEM). In the first scheme, the regular part
of the integrand is approximated by a suitable quasi--interpolation spline. In
the second scheme the regular part is approximated by a product of two spline
functions. The two schemes are tested and compared against other standard and
novel methods available in literature to evaluate different types of integrals
arising in the Galerkin formulation. Numerical tests reveal that under
reasonable assumptions the second scheme convergences with the optimal order in
the Galerkin method, when performing -refinement, even with a small amount
of quadrature nodes. The quadrature schemes are validated also in numerical
examples to solve 2D Laplace problems with Dirichlet boundary conditions
Caracterização Anatômica de Folhas e Inflorescências de Espécies de Lavanda (lamiaceae) utilizadas como Medicinais no Brasil
http://dx.doi.org/10.5902/2179460X13654Plants of the genus Lavandula denominated communly as lavenders are aromatic originated in Europe, especially from the Mediterranean area and belonging to the Lamiceae group. There is little information about the anatomy of plants of this gender, so we prioritized to identify the anatomical characters of Lavandula angustifolia Mill and Lavandula dentata L. to assist their own identification. For the historical analysis it was performed the middle part of young leaves and inflorescences in full bloom, from transverse sections made freehand with the help of razor and Styrofoam and the help of optical microscope and common digital camera (Olympus SP – 800UZ). It was also performed paradermical scraping with freehand from the abaxial surface of leaves and inflorescences and macerated dried material analysis of these organs. We sought to identify and classify the trichomes, the anatomical characteristics of leaves and inflorescences (flowers and bracts), and the powder of these agencies to compare the results obtained. In the anatomical characters examined, both from fresh material as the macerated material, there were similarities between the two species and morphology of epidermal cells, cuticle, stomata types, and heterogeneous dorsiventral mesophyll, and glandular trichomes in the leaves. L. dentata presents two larger secondary vessels conductors in the middle part of the leaves, while in angustifolia L. these vessels are all identical and with smaller gauges.http://dx.doi.org/10.5902/2179460X13654Plantas do gênero Lavandula denominadas comumente de alfazemas ou lavandas, são aromáticas originárias da Europa, especificamente da região do Mediterrâneo e pertencentes à Lamiaceae. Em função da escassez de informações acerca da anatomia de plantas deste gênero, objetivou-se conhecer os caracteres anatômicos de Lavandula angustifolia Mill. e Lavandula dentata L. para auxiliar na identificação das mesmas. Para a análise histológica foi utilizada a parte mediana de folhas adultas e de inflorescências (flores e brácteas) em plena floração, a partir de secções transversais feitas à mão livre com o auxílio de lâmina de barbear e isopor, visualizadas e analisadas a partir de microscópio óptico e câmera digital, marca Olympus SP – 800 UZ. Realizou-se raspagem paradérmica também à mão livre da face abaxial das folhas e inflorescências e análise de material seco macerado destes órgãos. Buscou-se identificar e classificar os tricomas, estudar as características anatômicas de folhas e inflorescências (flores e brácteas), além do pó destes órgãos para confrontar os resultados obtidos. Nos caracteres anatômicos analisados, tanto do material fresco quanto do material macerado, verificou-se semelhanças entre as duas espécies como morfologia das células epidérmicas, cutícula, tipos de estômatos, mesofilo dorsiventral e heterogêneo, tricomas tectores e glandulares observados nas folhas. L. dentata apresentou dois vasos condutores secundários de maior porte na parte mediana das folhas, enquanto que em L. angustifolia todos estes vasos são menores e de calibres idênticos
Microfluidic-based immunohistochemistry for breast cancer diagnosis: a comparative clinical study.
Breast cancer is a highly heterogeneous disease. The efficacy of tailored therapeutic strategies relies on the precise detection of diagnostic biomarkers by immunohistochemistry (IHC). Therefore, considering the increasing incidence of breast cancer cases, a concomitantly time-efficient and accurate diagnosis is clinically highly relevant. Microfluidics is a promising innovative technology in the field of tissue diagnostic, enabling for rapid, reliable, and automated immunostaining. We previously reported the microfluidic-based HER2 (human epidermal growth factor receptor 2) detection in breast carcinomas to greatly correlate with the HER2 gene amplification level. Here, we aimed to develop a panel of microfluidic-based IHC protocols for prognostic and therapeutic markers routinely assessed for breast cancer diagnosis, namely HER2, estrogen/progesterone receptor (ER/PR), and Ki67 proliferation factor. The microfluidic IHC protocol for each marker was optimized to reach high staining quality comparable to the standard procedure, while concomitantly shortening the staining time to 16 min-excluding deparaffinization and antigen retrieval step-with a turnaround time reduction up to 7 folds. Comparison of the diagnostic score on 50 formaldehyde-fixed paraffin-embedded breast tumor resections by microfluidic versus standard staining showed high concordance (overall agreement: HER2 94%, ER 95.9%, PR 93.6%, Ki67 93.7%) and strong correlation (ρ coefficient: ER 0.89, PR 0.88, Ki67 0.87; p < 0.0001) for all the analyzed markers. Importantly, HER2 genetic reflex test for all discordant cases confirmed the scores obtained by the microfluidic technique. Overall, the microfluidic-based IHC represents a clinically validated equivalent approach to the standard chromogenic staining for rapid, accurate, and automated breast cancer diagnosis
d-Wave Spin Density Wave phase in the Attractive Hubbard Model with Spin Polarization
We investigate the possibility of unconventional spin density wave (SDW) in
the attractive Hubbard model with finite spin polarization. We show that
pairing and density fluctuations induce the transverse d-wave SDW near the
half-filling. This novel SDW is related to the d-wave superfluidity induced by
antiferromagnetic spin fluctuations, in the sense that they are connected with
each other through Shiba's attraction-repulsion transformation. Our results
predict the d-wave SDW in real systems, such as cold Fermi atom gases with
population imbalance and compounds involving valence skipper elements
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