Methodological consensus on clinical proton MRS of the brain: Review and recommendations

© 2019 International Society for Magnetic Resonance in Medicine Proton MRS (1H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi-adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use

Structure evolution in amylopectin/ethylene glycol mixtures by H-bond formation and phase separation studied with dielectric relaxation spectroscopy

The interaction between amylopectin, a starch polysaccharide, and ethylene glycol (EG) was investigated using broad-band dielectric relaxation spectroscopy. Water-free amylopectin (AP) was mixed with 21 wt % ethylene glycol. This resulted in a continuous ethylene glycol phase, as well as a molecularly mixed AP/EG fraction. After storage at room temperature or annealing, the mixture shows dynamic properties typical of a polymer with weak intermolecular interactions, suggesting that EG binds preferentially to AP and forms intrachain H-bridges leading to increased chain stiffness and thus an increased glass transition temperature. This structure evolution is accompanied by a sharp reduction in the size of the ethylene glycol droplets to a few nanometers, as revealed by pronounced confinement effects in the alpha-relaxation of the dispersed EG

Using top-down CAD tools for mixed analog/digital ASICs : a practical design case

A mixed analog/digital ASIC from a real satellite application (a radiation detector front-end) hasbeen designed, simulated and processed according to a hierarchical top-down design methodology. CAD tools(commercial and academic) have been used as much as possible. The top-down methodology is discussed andillustrated by going through the different steps of the ASIC design. At each level the different choices and tradeoffs are briefly discussed and practical difficulties of top-down design are pointed out. One of the most importantproblems in top-down mixed-signal ASIC design-modeling and verification-is highlighted and discussed indetail

Synthesis of hyaluronic-acid-related oligosaccharides and analogues, as their 4-methoxyphenyl glycosides, having N-acetyl-β-D-glucosamine at the reducing end

To contribute to the possibilities to study the ability of oligosaccharide fragments of hyaluronic acid to induce angiogenesis, several hyaluronic-acid-related oligosaccharides and their 6-O-sulfated analogues were synthesised as their 4-methoxyphenyl glycosides having 2-acetamido-2-deoxy-D-glucopyranose at the reducing end. In all syntheses described, the D-glucopyranosyluronic acid residue was obtained by oxidation at C-6 of a corresponding D-glucopyranosyl residue after construction of the oligosaccharide backbone, using pyridinium dichromate and acetic anhydride.</p

Mixed analog/digital silicon compiler for space applications

The goal of the research project that is presented in this paper, is the development of a mixed analog/digital silicon compiler. The compiler is targeted to the architectural design of a mixed analog/digital signal acquisition and processing chain for space applications. The user has to describe the functionality and performance requirements of a system to be de signed. The compiler then translates the system description into an architecture of low level modules such as A/D converters, amplifiers and filters, as well as digital control sections. The layouts of the different modules will be generated by dedicated analog or digital module generators. Finally, the compiler assembles the layout of the total system. The necessary verifications at different levels during the design process will be performed by a mixed signal simulator. The general requirements and design flow of the silicon compiler will be discussed, together with the application domain of the compiler

Mutations in the Glucocorticoid Receptor DNA-binding Domain Mimic an Allosteric Effect of DNA

Introduction The expression of genetic information is governed largely by sequence-specic DNA-binding proteins that activate or repress transcription by RNA polymerase. Although these proteins commonly contain discrete DNA-binding and transcriptional regulatory domains that can be separated articially, experimental evidence suggests that in some regulatory proteins these domains communicate with each other to operate as integrated units (Lefstin &amp; Yamamoto, 1998). Examples of such proteins are found in the intracellular receptors, an extensive superfamily of transcriptional regulatory proteins that is represented in all metazoans. Members of this superfamily are characterized by a conserved DNA-binding domain (DBD) with two zinc ions each coordinated by four cysteine residues. Although some intracellular receptor superfamily members bind DNA as monomers, most known members bind to DNA sites as homodimers, heterodimers with another superfamily member, or in conjunction with unrelate