MR-compatible Electrophysiology Recording System for Multimodal Imaging

Simultaneous acquisition of functional magnetic resonance imaging (fMRI) and electrophysiological recordings is an emerging multimodal neuroimaging strategy for studying brain functions. However, the strong magnetic field generated during fMRI greatly degrades the electrophysiological signal quality during simultaneous acquisition. Here, I developed a low powered, miniaturized, system – “ECHO” which delivers a hardware and software solution to overcome the challenges presented by multimodal imaging. The device monitors fluctuations in electromagnetic field during fMRI and synchronizes amplification and sampling of electrophysiological signals to minimize effects of gradient and RF artifacts (electromagnetic artifacts). Furthermore, I introduced a concept of wirelessly transmitting recorded data through the MRI receiver coil. ECHO transmits the data at a frequency visible to the MRI receiver coil, after which the transmitted data is readily separable from the MRI image in the frequency domain. The MR-compatibility of the recorder was evaluated through a series of experiments with a phantom to study its effects on the MRI image quality. To further evaluate the effectiveness of ECHO, I recorded electrocardiogram and local field potential (evoked potential) in live rats during concurrent fMRI acquisition. In summary, ECHO offers a ‘plug and play’ solution to capture artifact-free electrophysiological data without the need of expensive amplifiers or synchronization hardware which require physical connection to the MRI scanner. This device is expected to make multimodal imaging more accessible and be applied for a broad range of fMRI studies in both the research and clinical fields

Modeling and Generating Tailored Distribution Middleware for Embedded Real-Time Systems

International audienceDistributed real-time embedded (DRE) systems are becoming increasingly complex. They have to meet more and more stringent requirements, either functional or non-functional. Because of this, DRE systems development makes use of formal methods for verification; and, in some cases, generation of proven code. The distribution aspects are typically handled by a middleware, which must meet the system constraints. In this article, we describe our approach to model and generate middleware-based distributed systems for DRE applications. Our methodology is a three-step approach. First, we model the high-level inter-component interactions using connectors. We then use the Architecture Analysis and Design Language (AADL) as a pre-implementation description language to capture all the non-functional aspects of the system. Finally, we generate actual application code and the appropriate middleware from the AADL description. In order to demonstrate the feasibility of our approach, we created an application generator, Gaia. It is part of the Ocarina AADL tool suite and generates application source code for use with the PolyORB middleware

Antiendomysium antibodies assay in the culture medium of intestinal mucosa: an accurate method for celiac disease diagnosis

Background Celiac disease (CD) diagnosis is becoming more difficult as patients with no intestinal histology lesions may also be suffering from CD. Aim To evaluate the diagnostic accuracy of antiendomysium (EmA) assay in the culture medium of intestinal biopsies for CD diagnosis. Patients and methods The clinical charts of 418 patients with CD and 705 non-CD controls who had all undergone EmA assay in the culture medium were reviewed. Results EmA assay in the culture medium had a higher sensitivity (98 vs. 80%) and specificity (99 vs. 95%) than serum EmA/antibodies to tissue transglutaminase (anti-tTG) assay. All patients with CD who were tested as false-negatives for serum EmA and/or anti-tTG (32 adults and 39 children) carried the human leukocyte antigen alleles associated to CD. Furthermore, during the follow-up, four patients with negative-serum EmA/anti-tTG, normal villi architecture, and positive-EmAs in the culture medium, developed villous atrophy and underwent gluten-free diet with consequent resolution of the symptoms and complete intestinal histology recovery. Conclusion EmA assay in the culture medium should be included in the diagnostic criteria for CD diagnosis in 'seronegative' patients. Eur J Gastroenterol Hepatol 23:1018-1023 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

Sox10 is required for Schwann cell identity and progression beyond the immature Schwann cell stage

The Sox10 transcription factor is required to maintain as well as specify glial identity, adding new causes for the neuropathies associated with SOX10 mutations

Broadband anti-reflection coating for the meter class Dark Energy Spectroscopic Instrument lenses

The Dark Energy Spectroscopic Instrument (DESI), currently under construction, will be used to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers, in turn, feed ten broad-band spectrographs. We will describe the broadband AR coating (360 nm to 980nm) that was applied to the lenses of the camera system for DESI using ion assisted deposition techniques in a 3 m coating chamber. The camera has 6 lenses ranging in diameter from 0.8 m to 1.14 m, weighing from 84 kg to 237 kg and made from fused silica or BK7. The size and shape of the surfaces provided challenges in design, uniformity control, handling, tooling and process control. Single surface average transmission and minimum transmission met requirements. The varied optical surfaces and angle of incidence considerations meant the uniformity of the coating was of prime concern. The surface radius of curvature (ROC) for the 12 surfaces ranged from nearly flat to a ROC of 611 mm and a sag of 140 mm. One lens surface has an angle of incidence variation from normal incidence to 40°. Creating a design with a larger than required bandwidth to compensate for the non-uniformity and angle variation created the ability to reduce the required coating uniformity across the lens and a single design to be used for all common substrate surfaces. While a perfectly uniform coating is often the goal it is usually not practicable or cost effective for highly curved surfaces. The coating chamber geometry allowed multiple radial positions of the deposition sources as well as substrate height variability. Using these two variables we were able to avoid using any masking to achieve the uniformity required to meet radial and angle performance goals. Very broadband AR coatings usually have several very thin and optically important layers. The DESI coating design has layers approaching 3 nm in thickness. Having sensitive thin layers in the design meant controlling layer thickness and azimuthal variation were critical to manufacturing repeatability. Through use of strategically placed quartz crystal monitors combined with stable deposition plumes, the manufacturing variability was reduced to acceptable levels. Low deposition rates and higher rotation rates also provided some stability to azimuthal variation

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Comparative Studies of the Desert Rodent Dipodomys Merriami and Munich Wistar Rat Urine Concentrating Mechanisms

Comparative studies of the mammalian renal medulla suggest that variations in the architecture of the thin limb of Henle’s loop contribute to variations in ability to produce concentrated urine. For this study, tubules and blood vessels of the renal inner medulla were identified by indirect immunofluorescence using antibodies and lectins that recognize segmentspecific proteins. Variations in axial expression of the water channel aquaporin 1 and the Cl channel ClC-K1 in the descending thin limb, suggest that equilibration of luminal fluid by water reabsorption occurs along a greater proportion of each loop length, and Cl reabsorption occurs along a shorter proportion of each prebend loop length in Dipodomys than in the Munich-Wistar rat. Interstitial nodal spaces adjacent to CDs exist in both species and preferential solute diffusion into these spaces may play a significant role in driving fluid reabsorption from CDs. In the terminal papilla, the ATL-to-CD surface area ratio is markedly greater in the Munich-Wistar rat, suggesting that NaCl reabsorption may have less of an impact on water reabsorption from terminal CDs in Dipodomys