XDS: a flexible beamline for X-ray diffraction and spectroscopy at the Brazilian synchrotron

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe majority of the beamlines at the Brazilian Synchrotron Light Source Laboratory (LNLS) use radiation produced in the storage-ring bending magnets and are therefore currently limited in the flux that can be used in the harder part of the X-ray spectrum (above approximate to 10keV). A 4T superconducting multipolar wiggler (SCW) was recently installed at LNLS in order to improve the photon flux above 10keV and fulfill the demands set by the materials science community. A new multi-purpose beamline was then installed at the LNLS using the SCW as a photon source. The XDS is a flexible beamline operating in the energy range between 5 and 30keV, designed to perform experiments using absorption, diffraction and scattering techniques. Most of the work performed at the XDS beamline concentrates on X-ray absorption spectroscopy at energies above 18keV and high-resolution diffraction experiments. More recently, new setups and photon-hungry experiments such as total X-ray scattering, X-ray diffraction under high pressures, resonant X-ray emission spectroscopy, among others, have started to become routine at XDS. Here, the XDS beamline characteristics, performance and a few new experimental possibilities are described.The majority of the beamlines at the Brazilian Synchrotron Light Source Laboratory (LNLS) use radiation produced in the storage-ring bending magnets and are therefore currently limited in the flux that can be used in the harder part of the X-ray spectrum (above approximate to 10keV). A 4T superconducting multipolar wiggler (SCW) was recently installed at LNLS in order to improve the photon flux above 10keV and fulfill the demands set by the materials science community. A new multi-purpose beamline was then installed at the LNLS using the SCW as a photon source. The XDS is a flexible beamline operating in the energy range between 5 and 30keV, designed to perform experiments using absorption, diffraction and scattering techniques. Most of the work performed at the XDS beamline concentrates on X-ray absorption spectroscopy at energies above 18keV and high-resolution diffraction experiments. More recently, new setups and photon-hungry experiments such as total X-ray scattering, X-ray diffraction under high pressures, resonant X-ray emission spectroscopy, among others, have started to become routine at XDS. Here, the XDS beamline characteristics, performance and a few new experimental possibilities are described.23615381549FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2009/54115-801.05.0721.00-27/0144Sem informaçãoThe authors would like to thank all LNLS staff involved in the design, construction, commissioning and operation of XDS, in particular Regis T. Neuenschwander, Flavio Rodrigues, James F. Citadini, Joacir E. dos Santos, Andre L. Mesa, James R. Piton, Sergio R. Marques and Carlos R. Scorzato. We also acknowledge Dr Agustin Picco for kindly providing the silver nanoparticles. We are grateful for the financial support from FAPESP (project 2009/54115-8) and FINEP (project 01.05.0721.00-27/0144) that covered most of the construction and equipping of the beamline. FAL acknowledges support from CNPq

Chondroitin sulfate and glucosamine in the cartilage and subchondral bone repair of dogs - Histological findings

Chondroitin and glucosamine sulfate nutraceuticals are commonly used in the management of degenerative articular disease in veterinary routine. However, there are controversies on the contribution of these substances to articular cartilage. The purpose of this study was to evaluate the efficiency of a chondroitin and glucosamine sulfate-based veterinary nutraceutical on the repair of an induced osteochondral defect in a dog femoral condyle, by macroscopic, histological and histomorphometric analyses. The nutraceutical was orally administered the day following injury induction, every 24 hours (treated group, TG, n=24), compared with animals that did not receive the product (control group, CG, n=24). Six animals per group were anaesthetized for sample collection at 15, 30, 60 and 90 days after surgery. At 15 days, defects were macroscopically filled with red-pinkish tissue. After 30 days, whitish color tissue was observed, both in TG and CG animals, with firmer consistency to touch at 60 and 90 postoperative days. Histological analysis demonstrated that, in both groups, there was initial blood clot formation, which was subsequently substituted by a fibrin net, with capillary proliferation from the adjacent bone marrow and infiltration of mesenchymal cells in clot periphery. As cellular differentiation developed, repair tissue presented a fibrocartilage aspect most of the time, and new subchondral bone formation occurred in the deepest area corresponding to the defect. Histomorphometry suggested that the nutraceutical did not favor the articular cartilage repair process. It was concluded that nutraceutical did not significantly influence chondrocytes proliferation or hyaline architecture restoration.Os nutracêuticos compostos de sulfato de condroitina e glucosamina são comumente utilizados no manejo da doença articular degenerativa na rotina veterinária. Entretanto, existem controvérsias sobre a contribuição dessas substâncias à cartilagem articular. O objetivo deste trabalho foi avaliar a eficácia de um nutracêutico veterinário à base de sulfato de condroitina e glucosamina na reparação de defeitos osteocondrais induzidos no côndilo femoral de cães, através de análises macroscópica, histológica e histomorfométrica. O nutracêutico foi administrado no dia seguinte à indução da lesão, pela via oral, a cada 24 horas (grupo tratado - GT, 24 animais), sendo comparado a animais que não receberam o produto (grupo controle - GC, de igual número de animais). Aos 15, 30, 60 e 90 dias após a cirurgia, seis animais por grupo foram anestesiados para ser realizada a coleta das amostras. Aos 15 dias, os defeitos eram macroscopicamente preenchidos por tecido de coloração rósea a avermelhada. Já a partir dos 30 dias, observou-se preenchimento por tecido de coloração esbranquiçada, tanto nos animais do GT quanto nos do GC, com consistência mais firme ao toque digital aos 60 e 90 dias de pós-operatório. A análise histológica revelou que, em ambos os grupos, houve inicialmente formação de coágulo sanguíneo que, posteriormente, foi substituído por uma rede de fibrina, com proliferação de capilares a partir da medula óssea adjacente e infiltração de células mesenquimais na periferia do coágulo. À medida que se processou a diferenciação celular, o tecido de reparação se apresentou na maioria das vezes com aspecto de fibrocartilagem e, na região mais profunda da área correspondente ao defeito, ocorreu formação de osso novo subcondral. A histomorfometria sugeriu que o nutracêutico não favoreceu o processo de reparação da cartilagem articular. Concluiu-se que o nutracêutico não influenciou consideravelmente na proliferação de condrócitos nem na restauração da arquitetura hialina

Magnetoelastic and thermal effects in the BiMn2O5 lattice: a high-resolution x-ray diffraction study

High-resolution synchrotron x-ray diffraction measurements were performed on single crystalline and powder samples of BiMn2O5. A linear temperature dependence of the unit cell volume was found between T_{N}=38$K and 100 K, suggesting that a low-energy lattice excitation may be responsible for the lattice expansion in this temperature range. Between T* ~ 65 K and T_{N}, all lattice parameters showed incipient magnetoelastic effects, due to short-range spin correlations. An anisotropic strain along the a-direction was also observed below T*. Below T_{N}, a relatively large contraction of the a-parameter following the square of the average sublattice magnetization of Mn was found, indicating that a second-order spin hamiltonian accounts for the magnetic interactions along this direction. On the other hand, the more complex behaviors found for$b$and$c$ suggest additional magnetic transitions below T_{N} and perhaps higher-order terms in the spin hamiltonian. Polycrystalline samples grown by distinct routes and with nearly homogeneous crystal structure above T_{N} presented structural phase coexistence below T_{N}, indicating a close competition amongst distinct magnetostructural states in this compound.Comment: 23 pages, 7 figure