Energy sensitive X-ray phase contrast imaging with a CdTe-Timepix3 detector

The Timepix3 is a photon counting semiconductor detector that enables to simultaneously measure the energy and time of arrival of each incident X- ray photon. These properties, along with the high spatial resolution and high efficiency, due to the CdTe sensor material, can be exploited for several imaging applications, such as X-ray phase contrast imaging (XPCI). XPCI relies on the phase shift suffered by X-rays when traversing the sample. This study focuses on the free-space propagation XPCI and single mask edge illumination XPCI methods, which are two approaches that are well suited for laboratory implementations. Since both techniques are highly sensitive to charge-sharing, the Timepix3 energy and time information for each photon are used to minimize this effect by using pixel clustering methods. In addition, the performance of both XPCI techniques across a 30kVp source spectrum is studied using the energy-resolving capabilities of the detector. In both cases, the phase contrast and signal-to-noise ratio (SNR) are assessed as a function of different energy. Finally, it is demonstrated that phase contrast enhancement is feasible with pixel clustering and energy-selection for both XPCI techniques

Diabetes insipidus in a pacient with multiple sclerosis

Multiple Sclerosis (ME) is a chronic progressive disease characterized by relapses of demyelination that can occur anywhere in the brain stem, spinal cord and optic nerve. Since central diabetes insipidus (DI) is mainly caused by central nervous system damage (such as trauma, surgery, tumor, infection, sarcoidosis), ME is included among its possible etiologies. However, this association is not commonly described. The clinical suspicion must be made in the presence of polyuria and polydipsia or refractory hypernatremia (in patients without free access to water) during the evolution of ME. We will describe a clinical report in which this association occurred and, after the beginning of desmopressin therapy, the clinical findings were reverted.A esclerose múltipla (EM) é uma doença crônica e progressiva que se caracteriza por surtos de desmielinização que podem atingir qualquer topografia do cérebro, medula espinhal e nervo óptico. Sendo o diabetes insípido (DI) central causado, principalmente, em virtude de danos do sistema nervoso central (tais como trauma, cirurgia, tumor, infecção, sarcoidose), a EM está inclusa entre suas possíveis etiologias. Entretanto, a ocorrência dessa associação não é comumente descrita. A suspeita clínica deve ser feita na presença de poliúria e polidipsia ou hipernatremia refratária (em pacientes privados do acesso à água) durante a evolução da EM. Descreveremos um caso em que essa associação ocorreu e, após o início da terapêutica com desmopressina, a paciente reverteu o quadro clínico.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Monitoring of historical masonry structures with operational modal analysis: Two case studies

Two monuments in Portugal are being monitoring by the University of Minho: the Clock Tower of Mogadouro and the Church of Jerónimos Monastery, in Lisbon. Vibration sensors and temperature and relative air humidity sensors are installed in the two monuments. Operational modal analysis is being used to estimate the modal parameters, followed by statistical analysis to evaluate the environmental effects on the dynamic response. The aim is to explore damage assessment in masonry structures at an early stage by vibration signatures as a part of a heath monitoring process to preserve the historical constructions. The paper presents all the preceding dynamic analysis steps before the monitoring task, which includes the installation of the monitoring system, the system identification and subsequent FE model updating analysis, the automatic modal identification and the investigation of the influence of the environment on the identified modal parameters.(undefined

Dextran-Coated Magnetic Supports Modified with a Biomimetic Ligand for IgG Purification

The authors thank the financial support from Fundacao para a Ciencia e a Tecnologia through Grant PEst-C/EQB/LA0006/2011 and contracts no. PTDC/EBB-BIO/102163/2008, PTDC/EBB-BIO/098961/2008, PTDC/EBB-BIO/118317/2010, SFRH/BD/72650/2010 for V.L.D, and Santander Totta Bank - Universidade Nova de Lisboa for the Scientific Award 2009/2010. The authors are grateful to Dr. Abid Hussain and M. Telma Barroso (REQUIMTE, FCT-UNL, Portugal) for the preparation of the synthetic affinity ligands, to Lonza Biologics, U.K. (Dr. Richard Alldread), and the Animal Cell Technology Unit of ITQB-UNL/IBET (Dr. Paula M Alves and Dr. Ana Teixeira) for providing the cells and the culture bulks and to Mr. Filipe Cardoso and Prof. Paulo Freitas (INESC-MN, Lisbon, Portugal) for the help with the VSM measurements.Dextran-coated iron oxide magnetic particles modified with ligand 22/8, a protein A mimetic ligand, were prepared and assessed for IgG purification. Dextran was chosen as the agent to modify the surface of magnetic particles by presenting a negligible level of nonspecific adsorption. For the functionalization of the particles with the affinity ligand toward antibodies, three methods have been explored. The optimum coupling method yielded a theoretical maximum capacity for human IgG calculated as 568 ± 33 mg/g and a binding affinity constant of 7.7 × 10⁴ M⁻¹. Regeneration, recycle and reuse of particles was also highly successful for five cycles with minor loss of capacity. Moreover, this support presented specificity and effectiveness for IgG adsorption and elution at pH 11 directly from crude extracts with a final purity of 95% in the eluted fraction.proofpublishe