Measurements of neutron fluxes from tokamak plasmas using a compact neutron spectrometer.

A compact neutron spectrometer based on the BC-501A liquid organic scintillator was applied to neutron measurements at the TUMAN-3M tokamak. The spectrometer was calibrated using measurements from the ion beam of the cyclotron accelerator. Neutron spectra were measured during discharges using a neutral deuterium beam injection into the TUMAN-3M D-plasma. An energy distribution of the neutrons from the plasma that hit the spectrometer was obtained from the measured BC-501A instrumental spectra by the DeGaSum code using detector response functions obtained in the course of the calibration. This allowed for the estimation of the 2.45 MeV neutron yield and the evaluation of both the time evolution of the DD fusion rate and the characteristic time of the injected deuterium slowing down in discharges with neutral beam injection heating.

High resolution gamma-ray spectrometer with MHz capabilities for runaway electron studies at ASDEX Upgrade.

A new gamma-ray spectrometer with MHz capabilities has been developed to measure the bremsstrahlung emission spectrum in the gamma-ray energy band generated by MeV range runaway electrons in disruption experiments at ASDEX Upgrade. Properties of the runaway electrons are inferred from the measured bremsstrahlung spectrum by a deconvolution technique, particularly with regard to their maximum energy. Changes induced to the runaway electron velocity space are unambiguously observed both in massive gas injection and resonant magnetic perturbation experiments with the detector.

Ionic liquid crosslinkers for chiral imprinted nanoGUMBOS.

Molecularly imprinted polymers (MIPs) are an important class of selective materials for molecular specific sensors and separations. Molecular imprinting using non-covalent interactions in aqueous conditions still remains a difficult challenge due to interruption of hydrogen-bonding or electrostatic interactions water. Newly developed crosslinking ionic liquids are demonstrated herein to overcome problems of synthesizing aqueous MIPs, adding to previous examples of ionic liquids used as monomers in non-aqueous conditions or used as MIP solvents. Vinylimidazole ionic liquid crosslinkers were synthesized and subsequently explored as matrix supports for fabrication of molecularly imprinted polymeric nanoGUMBOS (nanoparticles derived from a group of uniform materials based on organic salts). Each of the four crosslinkers incorporated a unique functional spacer between the vinylimidazole groups, and the performance of the corresponding molecularly imprinted polymers was evaluated using chiral recognition as the diagnostic. High uptake values for l-tryptophan were found in the 13-87µmol/g range; and chiral recognition was determined via binding ratios of l-tryptophan over d-tryptophan that ranged from 5:1 to 13:1 for polymers made using different crosslinkers. Not only are these materials good for chiral recognition, but the results highlight the utility of these materials for imprinting aqueous templates such as biological targets for theranostic agents.

[Unusual 99(m) Tc-pyrophosphate accumulation in aortic aneurysm detected by bone scintigraphy].

A clinical observation of focal accumulation of 99(m)Tc-pyrophosphate in aortic aneurysm, simulating skeletal pathology of the lumbar vertebra in planar scintigraphy mode, is presented. Additional single-photon emission computed tomography combined with computed tomography-something view allowed to confirm that the radiotracer uptake focus was localized in the distal part of the aneurysm, in the zone of lumen subocclusion by a calcified thrombus. It is suggested that the local tracer accumulation is not only due to calcification but also due to inflammatory, a factor that plays a role in the genesis of aortic aneurysm.

[Phantom kidney at angionephroscintigraphy].

Based on the analysis of the data available in the literature and own clinical observations, the authors consider the diagnostic value of the little known scintigraphic phantom kidney phenomenon, a vascular pool that is detected at the angiographic stage of 99mTc-DTPA dynamic renal scintigraphy and that mimics a removed or absent kidney. The paper describes two cases of the phantom kidney. In one case, the phantom kidney detected on the side of nephrectomy manifested a kidney cancer recurrence in the bed of the removed organ; in the other, the kidney-like vascular pool in the patient with left-sided pelvic dystopic kidney was due to the recording of the intestinal vasculature at the site of the expected kidney location. Adherence to a number of methodical conditions for conducting a study, as well as combined single-photon emission computed tomography/computed tomography examination will be able to avoid interpretation errors and to ensure an adequate further diagnostic algorithm.

Leukaemia cutis in chronic lymphocytic leukaemia following varicella zoster virus reactivation.

We report a case of a 75-year-old male with indolent chronic lymphocytic leukaemia (CLL) for 8 years, who presented with a 6-month history of a painful, zosteriform eruption in a T3-4 distribution that evolved into an unusual crop of papular nodules. Upon biopsy and immunostaining of these lesions CLL was proven consistent with leukaemia cutis related to varicella-zoster virus reactivation. In the absence of other treatment indices, he was commenced on chlorambucil with successful resolution of both his pain and the lesions.

[Single-photon emission computed tomography in the diagnosis of myocardial perfusion abnormalities in patients with rheumatoid arthritis: preliminary data].

Increased cardiovascular morbidity and mortality in patients with rheumatoid arthritis (RA) may be attributed to the fact that a systemic inflammation existing in this disease may trigger the development of atherosclerosis. 99mTC-MIBI (4,2-methoxyisobutyl isonitrile) is a compound that permits myocardial perfusion to be visualized and has been proposed for the evaluation of the latter in patients with RA. Analysis of the results of the studies revealed transient myocardial ischemia areas in patients who did not take methotrexate while those who used it were found to have diminished perfusion areas that were, however, clinical insignificant.

Energy resolution of gamma-ray spectroscopy of JET plasmas with a LaBr3 scintillator detector and digital data acquisition.

A new high efficiency, high resolution, fast γ-ray spectrometer was recently installed at the JET tokamak. The spectrometer is based on a LaBr3(Ce) scintillator coupled to a photomultiplier tube. A digital data acquisition system is used to allow spectrometry with event rates in excess of 1 MHz expected in future JET DT plasmas. However, at the lower rates typical of present day experiments, digitization can degrade the energy resolution of the system, depending on the algorithms used for extracting pulse height information from the digitized pulses. In this paper, the digital and analog spectrometry methods were compared for different experimental conditions. An algorithm based on pulse shape fitting was developed, providing energy resolution equivalent to the traditional analog spectrometry method.

Gamma ray spectroscopy at high energy and high time resolution at JET.

In fusion plasmas gamma ray emission is caused by reactions of fast particles, such as fusion alpha particles, with impurities. Gamma ray spectroscopy at JET has provided valuable diagnostic information on fast fuel as well as fusion product ions. Improvements of these measurements are needed to fully exploit the flux increase provided by future high power experiments at JET and ITER. Limiting aspects are, for instance, the count rate capability due to a high neutron/gamma background combined with slow detector response and a modest energy resolution due to the low light yield of the scintillators. This paper describes the solutions developed for achieving higher energy resolution, signal to background, and time resolution. The detector design is described based on the new BrLa3 scintillator crystal. The paper will focus on hardware development, including a photomultiplier tube capable of stable operation at counting rate as high as 1 MHz, the magnetic shielding, and the fast digital data acquisition system.

Polymerized lyotropic liquid crystal assemblies for materials applications.

The development of functional materials with nanometer-scale architectures and the effect of these architectures on their chemical and physical properties are currently of great interest in materials design. Polymerizable lyotropic liquid crystal (LLC) assemblies provide a facile entry into this area by allowing one to fix the inherent order in these systems using covalent bonds to create robust, nanostructured materials. The use of the cross-linked inverted hexagonal phase in templated nanocomposite formation and heterogeneous catalysis has been demonstrated. Additionally, the polymerization of LLC mesogens in the regular hexagonal and bicontinuous cubic phases is being targeted for future developments in functional materials. Future directions for new applications of these materials are also discussed.

Sulfide-mediated dehydrative glycosylation.

The development of a new method for glycosylation with 1-hydroxy glycosyl donors employing dialkyl sulfonium reagents is described. The process employs the reagent combination of a dialkyl sulfide and triflic anhydride to effect anomeric bond constructions. This controlled dehydrative coupling of various C(1)-hemiacetal glycosyl donors and nucleophilic acceptors proceeds by way of a sulfide-to-sulfoxide oxidation process in which triflic anhydride serves as the oxidant.

Supramolecular chemistry: functional structures on the mesoscale.

Supramolecular chemistry deals with the chemistry and collective behavior of organized ensembles of molecules. In this so-called mesoscale regime, molecular building blocks are organized into longer-range order and higher-order functional structures via comparatively weak forces. As one of the modern frontiers in chemistry, supramolecular chemistry heralds many promises that range from biocompatible materials and biomimetic catalysts to sensors and nanoscale fabrication of electronic devices.

Stereoselective synthesis of 2-hydroxy-alpha-mannopyranosides from glucal donors.

[figure: see text] Direct synthetic access to 2-hydroxy-alpha-mannopyranosides from glucal donors is accomplished via a one-pot stereoselective oxidative glycosylation reaction, employing the reagent combination of dibenzothiophene bis(triflate) and dibenzothiophene-5-oxide.

Synthesis and determination of absolute configuration of the bicyclic guanidine core of batzelladine A.

[reaction: see text] The synthesis of a selectively protected form of the bicyclic guanidine fragment of batzelladine A from L-aspartic acid is reported, thereby establishing the absolute configuration of the bicyclic guanidine ring system within the natural product.

A new C(1)-auxiliary for anomeric stereocontrol in the synthesis of alpha-sialyl glycosides.

The installation of the novel N,N-dimethylglycolamide ester auxiliary onto the C(1)-position of protected neuraminic acid donors allows for the exploitation of C(1)-neighboring group participation to generate sialoside conjugates with good to excellent alpha-selectivity under a variety of sialylation protocols, including those that would otherwise lead to nonselective or beta-selective sialoside products.

Synthesis of the trisaccharide portion of the immunologic adjuvant QS-21A via sulfonium-mediated oxidative and dehydrative glycosylation.

[see structure]. The first synthesis of the trisaccharide fragment of the potent immunologic adjuvant QS-21A is reported. The key steps involve the application of sulfonium-mediated oxidative and dehydrative glycosidic couplings to construct the anomeric linkages in a short and convergent assembly of the branched trisaccharide.

Synthesis of glycosyl-1-phosphates via dehydrative glycosylation.

[reaction: see text] Direct synthetic access to glycosyl-1-phosphates is accomplished with the dehydrative coupling of carbohydrate hemiacetals and dialkyl phosphates, employing dibenzothiophene-5-oxide and triflic anhydride. The procedure offers a new and versatile method for efficient preparation of a host of glycosyl-1-phosphates of variable structure with good control over anomeric selectivity.

Acetamidoglycosylation with Glycal Donors: A One-Pot Glycosidic Coupling with Direct Installation of the Natural C(2)-N-Acetylamino Functionality.

Nitrogen transfer to glycals: A new method for direct C2-aza-glycosylation with glycal donors has been developed (see scheme), employing the new reagent combination of thianthrene-S-oxide and trifluoroacetic anhydride for glycal activation, in an overall one-pot procedure.