Tandem mass spectrometry for the direct assay of lysosomal enzymes in dried blood spots: application to screening newborns for mucopolysaccharidosis II (Hunter Syndrome)

We have developed a tandem mass spectrometry based assay of iduronate-2-sulfatase (IdS) activity for the neonatal detection of mucopolysaccharidosis II (MPS-II, Hunter Syndrome). The assay uses a newly designed synthetic substrate (IdS-S) consisting of α-L-iduronate-2-sulfate, which is glycosidically conjugated to a coumarin and a linker containing a tert-butyloxycarbamido group. A short synthesis of the substrate has been developed that has the potential of being scaled to multigram quantities. Sulfate hydrolysis of IdS-S by IdS found within a 3 mm dried blood spot specifically produces a nonsulfated product (IdS-P) which is detected by electrospray tandem mass spectrometry and quantified using a deuterium-labeled internal standard, both carried out in positive ion mode. Analysis of DBS from 75 random human newborns showed IdS activities in the range of 4.8-16.2 (mean 9.1) μmol/(h L of blood), which were clearly distinguished from the activities measured for 14 MPS-II patients at 0.17-0.52 (mean 0.29) μmol/(h L of blood). The assay shows low blank activity, 0.15 ± 0.03 μmol/(h L of blood). The within-assay coefficient of variation (CV) was 3.1% while the interassay CV was 15%.     

Solvent Polarity Dependent Photophysics of a Fixed-Distance,Symmetric Chlorophyll Dimer. A Model of the Special Pair in Photosynthetic Reaction Centers

The synthesis and properties of a fixed-distance symmetric bis-pyrochlorophyllide-a molecule are described. The molecule, 1 , consists of two methyl pyrochlorophyllide-a (MePChlide-a) moieties which share a common vinyl group at the 2-position of each macrocycle. The two chlorophylls are trans to one another across the vinyl linkage. The dihedral angle between the plane of each macrocycle and the vinyl linkage is about 50°. The Q_y absorption band of this dimer occurs at 689 nm and is essentially independent of solvent. The band is red-shifted by about 27 run relative to that of MePChlide-a. The fluorescence maximum of 1 occurs at 722 nm. This is a red-shift of 49 nm relative to methyl MePChlide-a. The circular dichroism spectrum of 1 shows strong, nonconservative bands in the red region. The fluorescence quantum yield, fluorescence lifetimes, and picosecond transient absorbance kinetics all exhibit a very strong dependence on solvent polarity. The fluorescence quantum yields of 1 in toluene, butyronitrile, and N, N-dimethyl formamide (DMF) are 0.18, 0.008, and 0.002, respectively. The bleach of the 689 nm band (following excitation with a 1.5-ps, 610-nm laser pulse) recovers with single exponential time constants of 2.51 ns, 100 ps, and 64 ps in toluene, butyronitrile, and DMF, respectively. Possible mechanisms for the polarity-dependent increase of the nonradiative decay rate of 1 are considered.     

HEAT EXCHANGER FOR IN-GROUND HEAT STORAGE

The first phase of a research project using undisturbed soil for sensible heat storage is described. A laboratory scale model of a heat exchange system was constructed and tested. Thermal charging and recovery rates, modes of heat transport and transient temperature conditions, as well as over-all heat storage performance of the unit are given. The experimental results are compared with predictions of a numerical model based on mass and heat transport. A prototype field installation has been constructed and preliminary results are presented.     

Frost heave control of a chilled gas pipeline

This paper concerns the investigation of a possibility of controlling frost heave of a buried, chilled gas pipeline by heating cables. Experimental and numerical approaches were used to determine the influence of two heat sources placed underneath slab insulation. Saturated sand and highly frost-susceptible Niagara silt were chosen to represent two soil condition extremes regarding frost heave. Laboratory and mathematical models showed good agreement in predicting the size and shape of the frost bulb with variation of heat output from the cables. Experiments on Niagara silt demonstrated the engineering practicability of this system to control frost heaving of a pipeline.     

Risk Budget management in progressing underground works: International Society for Trenchless Technology (ISTT) and International Tunnelling Association (ITA) Joint Working Group Report

There is a mass of detailed data concerning technical risk assessment methods and practices for underground work. But there is very little advice or guidance on the broad apportionment of the total risk between the various phases of an underground project or general advice on how risk might be managed. The Working Group has produced a generic Risk Budget covering five typical phases of an underground works project, which illustrates the heavy bias of risk towards the early phases. Using a practical example the report illustrates how project risk can be managed in a structured manner.     

Highly Ordered N‐Doped Carbon Dots Photosensitizer on Metal–Organic Framework‐Decorated ZnO Nanotubes for Improved Photoelectrochemical Water Splitting

In spite of having several advantages such as low cost, high chemical stability, and environmentally safe and benign synthetic as well as operational procedures, the full potential of carbon dots (CDs) is yet to be explored as photosensitizers due to the challenges associated with the fabrication of well‐arrayed CDs with many other photocatalytic heterostructures. In the present study, a unique combination of metal–organic framework (MOF)‐decorated zinc oxide (ZnO) 1D nanostructures as host and CDs as guest species are explored on account of their potential application in photoelectrochemical (PEC) water splitting performance. The synthetic strategy to incorporate well‐defined nitrogen‐doped carbon dots (N‐CDs) arrays onto a zeolitic imidazolate framework‐8 (ZIF‐8) anchored on ZnO 1D nanostructures allows a facile unification of different components which subsequently plays a decisive role in improving the material's PEC water splitting performance. Simple extension of such strategies is expected to offer significant advantages for the preparation of CD‐based heterostructures for photo(electro)catalytics and other related applications.     

Energetic and Environmental Optimization of the Biomass Using

Biomass energy conversion can be done in several ways-combustion, gasification, pyrolysis or anaerobic fermentation （biogas production）. Each of these technologies has certain advantages and disadvantages from the point of view of energy generation for final consumption. In parallel, each of them has certain environmental impact in terms of emissions. The proposed EU directive prefers utilization of primary energy sources by application of highly efficient co-generation. Such change in assessment of energy effectiveness also means a completely new approach in assessment of current technologies. This report presents a guide for optimization of biomass energy conversion technologies assuming application of this new condition and minimal environmental impact. Specific values of emissions from particular technologies are used for the evaluation.     

Low-loss high entropy relaxor-like ferroelectrics with A-site disorder

Relaxor ferroelectric ceramics are good candidates for capacitor, sensor and actuator applications because of their high dielectric permittivity, high piezoelectric constant and high value of field induced strain, respectively. However, their dielectric loss is usually relatively high, which is a problem for actual applications. The introduction of the high entropy concept opens up the possibility of developing new multi-element relaxor-like ferroelectric materials with short-range ordered polar structures having short relaxation times to decrease their loss. Here we present a new high entropy A-site disordered perovskite (Pb_0.25Ba_0.25Sr_0.25Ca_0.25)TiO₃ relaxor-like ferroelectric. Moreover, the ceramic has low loss (<0.015) from room temperature to 125 °C. The relaxor-like nature of the material is proved by dielectric and ferroelectric measurements. This work demonstrates the great potential of high entropy perovskites as relaxor-like ferroelectrics with a wide compositional window for tuning their properties for different applications.     

Imipenem-resistant Ps. aeruginosa bacteraemia in cancer patients: risk factors, clinical features and outcome

Ninety nine patients with 101 bacteraemic episodes due to Ps. aeruginosa (PA) within 6 years were divided into two groups according to their resistance to imipenem-91 due to imipenem sensitive (ISPA) and 10 due to resistant (IRPA). Risk factors, the clinical course and the outcome were evaluated and compared. Acute leukaemia, prolonged neutropenia, previous therapy with amikacin, third generation of cephalosporins, imipenem and prophylaxis by quinolones were significantly more frequently associated with IRPA. Imipenem resistant PA bacteraemia were associated with higher incidence of septic shock (40% vs 19.8%, p < 0.02) and death (33.3%) than ISPA bacteraemias. Since 1992, when first IRPA appeared, the incidence of imipenem resistance increased tenfold, and in 1994, up to 10% of PA causing bloodstream infections in cancer patients in our center were imipenem resistant. (Tab. 3, Ref. 8.).     

Radioprotective effects of basic copper carboxylate complexes

The radioprotective activity of eight selected copper (II) carboxylates--Cu (RCOO)2.nL (R = alkyl, aryl, 2-furyl and 2-thienyl; L usually represents water)--was assayed in a model of lethally gamma-irradiated (9 Gy, 0.97 Gy/min) mice. The compounds tested were applied (as solutions in saline) s.c. in three single doses of 20 mumol/kg 48.24 and 6 h before irradiation. The highest radioprotective effects were measured by survival of mice achieved after premedication of animals with copper (II) 2-thenoate monohydrate (77%), copper (II) acetylsalicylate (64%), copper (II) 2-methoxybenzoate monohydrate (62%) and copper (II) acetate monohydrate (54%). On the other hand, survival of vehicle-pretreated mice was only 10%. The observed biological properties of complexes are discussed in relation to their structures.