The aging effect on prostate metabolite concentrations measured by <Superscript>1</Superscript>H MR spectroscopy

Objective

The effects of aging, magnetic field and the voxel localization on measured concentrations of citrate (Cit), creatine (Cr), cholines (Cho) and polyamines (PA) in a healthy prostate were evaluated.

Materials and methods

36 examinations at both 1.5T and 3T imagers of 52 healthy subjects aged 19–71 years were performed with PRESS 3D-CSI sequences (TE = 120 and 145 ms). Concentrations in laboratory units and their ratios to citrate were calculated using the LCModel technique. Absolute concentrations were also obtained after the application of correction coefficients. Statistical analysis was performed using a robust linear mixed effects model.

Results

Significant effects of aging, the magnetic field strength and the voxel position in central (CZ) or peripheral (PZ) zones on all measured metabolites were found. The concentrations (mmol/kg wet tissue) including prediction intervals in a range of 20–70 years were found: Cit: 7.9–17.2; Cho: 1.4–1.7; Cr: 2.8-2.5; PA (as spermine): 0.6–2.1 at 3T in CZ. In PZ, the concentrations were higher by about 10 % as compared to CZ.

Conclusion

Increasing citrate and spermine concentrations with age are significant and correlate well with a recently described increase of zinc in the prostate. These findings should be considered in decision-making if the values obtained from a subject are in the range of control values.

     

Heterobimetallorganische 1,2‐(N,N‐Dimethylaminomethyl)ferrocenyl‐Derivate des vier‐ und zweiwertigen Zinns: Synthesen,Charakteristika und Kristallstrukturen

SnCl₄ reacts with [1,2‐(N,N‐dimethylaminomethyl) ferrocenyl]lithium (FcNLi) under formation of the organo tin compounds of the four valued tin (FcN)_n SnCl _4‐n [n = 1( 1 ), 2( 2 ), 3( 3 ), 4( 4 )]. The heterobimetallic chelate complex bis[1,2‐(N,N‐dimethylaminomethyl)ferrocenyl]tin(II) (FcN)₂ Sn ( 5 ) is formed at the reaction of SnCl₂ with two equivalents of FcNLi. The heterobimetallic tin compounds 1 — 5 were characterized by ¹H NMR‐, ¹³C‐NMR and mass spectroscopy, single crystal x‐ray analyses ( 1,3,4,5 ), ⁵⁷ Fe‐Moessbauer spectroscopy ( 1, 3, 4, 5 ), respectively cyclic voltammetry.     

Genome-Wide DNA Methylation in Policemen Working in Cities Differing by Major Sources of Air Pollution

DNA methylation is the most studied epigenetic mechanism that regulates gene expression, and it can serve as a useful biomarker of prior environmental exposure and future health outcomes. This study focused on DNA methylation profiles in a human cohort, comprising 125 nonsmoking city policemen (sampled twice), living and working in three localities (Prague, Ostrava and Ceske Budejovice) of the Czech Republic, who spent the majority of their working time outdoors. The main characterization of the localities, differing by major sources of air pollution, was defined by the stationary air pollution monitoring of PM2.5, B[a]P and NO₂. DNA methylation was analyzed by a genome-wide microarray method. No season-specific DNA methylation pattern was discovered; however, we identified 13,643 differentially methylated CpG loci (DML) for a comparison between the Prague and Ostrava groups. The most significant DML was cg10123377 (log₂FC = −1.92, p = 8.30 × 10⁻⁴) and loci annotated to RPTOR (total 20 CpG loci). We also found two hypomethylated loci annotated to the DNA repair gene XRCC5. Groups of DML annotated to the same gene were linked to diabetes mellitus (KCNQ1), respiratory diseases (PTPRN2), the dopaminergic system of the brain and neurodegenerative diseases (NR4A2). The most significant possibly affected pathway was Axon guidance, with 86 potentially deregulated genes near DML. The cluster of gene sets that could be affected by DNA methylation in the Ostrava groups mainly includes the neuronal functions and biological processes of cell junctions and adhesion assembly. The study demonstrates that the differences in the type of air pollution between localities can affect a unique change in DNA methylation profiles across the human genome.     

Nanometer size wear debris generated from ultra high molecular weight polyethylene in vivo

Ultra high molecular weight polyethylene (UHMWPE) wear debris is a major cause of long-term failure of total hip replacements. UHMWPE wear particle sizes range from submicron to several millimeters, but the particles below 10 μm exhibit the highest biological activity. Some in vitro wear particles, produced in joint simulators, were shown to be smaller than 0.2 μm and recently even in vitro particles as small as several tens of nanometers have been detected. This study brings the first evidence that nano-sized wear particles with sizes below 0.05 μm are produced in vivo. UHMWPE wear nanoparticles were revealed by high-resolution, field emission gun scanning electron microscopy (FEGSEM) in the periprosthetic tissues of two different patients. Purity of the isolated wear nanoparticles was confirmed by energy-dispersive analysis of X-rays (EDS) and infrared spectroscopy (IR). Morphology of wear nanoparticles was determined by image analysis of FEGSEM micrographs. The average equivalent diameters of wear particles in the first and the second patient were 18.5 and 21.2 nm, respectively. Nanoscale wear debris could only be reliably detected if the isolation protocol included intensive sonication and if higher-than-usual magnifications were employed during FEGSEM analysis.     

Solid-phase extraction of berries’ anthocyanins and evaluation of their antioxidative properties

Solid-phase extraction (SPE) was used to obtain anthocyanin-rich extracts from five berry species: chokeberry, elderberry, black currant, blackberry and blueberry. During SPE more than 94.4% of the sugars and more than 88.5% of the acids present in the crude extracts were separated. The SPE resulted in 90–95.6% anthocyanins recovery. The antioxidative properties of the anthocyanin-rich extracts were tested by measuring their oxygen radical absorption capacity (ORAC), hydroxyl radical averting capacity (HORAC), total peroxyl radical trapping antioxidant parameter (TRAP), scavenging of nitric oxide and inhibition of lipid peroxidation. Elderberry extract revealed the highest ORAC value of 5783 μmol TE/g. Chokeberry extract was the most potent inhibitor of lipid peroxidation and had the highest TRAP value of 4051 μmol TE/g. Blueberry extract had the highest HORAC result – 1293 μmol GAE/g and was the most powerful scavenger of NO. The high antioxidant activity according to all antioxidant assays revealed opportunities to apply these preparations as antioxidants.     

jSIPRO – Analysis tool for magnetic resonance spectroscopic imaging

Magnetic resonance spectroscopic imaging (MRSI) involves a huge number of spectra to be processed and analyzed. Several tools enabling MRSI data processing have been developed and widely used. However, the processing programs primarily focus on sophisticated spectra processing and offer limited support for the analysis of the calculated spectroscopic maps. In this paper the jSIPRO (java Spectroscopic Imaging PROcessing) program is presented, which is a java-based graphical interface enabling post-processing, viewing, analysis and result reporting of MRSI data. Interactive graphical processing as well as protocol controlled batch processing are available in jSIPRO. jSIPRO does not contain a built-in fitting program. Instead, it makes use of fitting programs from third parties and manages the data flows. Currently, automatic spectra processing using LCModel, TARQUIN and jMRUI programs are supported. Concentration and error values, fitted spectra, metabolite images and various parametric maps can be viewed for each calculated dataset. Metabolite images can be exported in the DICOM format either for archiving purposes or for the use in neurosurgery navigation systems.     

Loading-unloading shear behavior of rammed earth upon varying clay content and relative humidity conditions

This paper investigates the impact of clay and moisture contents on the shear behavior of compacted earth taking into account loading-unloading cycles. Fine sand was added to a natural soil, thereby obtaining three different soils with clay contents of 35%, 26%, and 17%, respectively. A series of triaxial tests was conducted on samples previously equilibrated at three different values of relative humidity (RH). The evolution of failure strength f_c, Young's modulus E, and residual strain ε_res was investigated according to the clay content and the RH, the last two parameters being measured during the loading-unloading cycles. Firstly, the relative humidity at which the samples were fabricated and conditioned was seen to have a strong impact on the mechanical characteristics of the earthen material. An increase in RH led to a decrease in both failure strength f_c and Young’s modulus E, and an increase in plastic strain. The tendencies were found to depend on the clay content of the samples. Secondly, with an increasing stress level, a progressive decrease in Young’s modulus and an increase in residual strain ε_res (after a loading-unloading cycle) appeared. Thirdly, within the range of the investigated clay contents, both failure strength f_c and residual strain ε_res increased with an increasing clay content at constant values of RH and confining pressure, the rate of this increase being a function of the RH. Young’s modulus E was relatively insensitive to changes in the clay content, its variation being less than 20% for all cases. Finally, based on a particular definition of Bishop's effective stress, involving a specific functional form χ(s), the failure states of all the samples were observed to lie approximately on a unique failure line crossing the origin in the (p′-q) plane regardless of the matric suction and confining pressure.     

Optimization of the strength of SOFC anode supports

During operation solid oxide fuel cells are stressed by temperature gradients and various internal and external mechanical loads, which must be withstood. This work deals with the optimization of the strength of as-sintered anode supported half-cells by imposing changes to production parameters, such as powder milling and sintering temperature. The strength was measured with the ball-on-ring method, and analyzed with a large displacement finite element model. Weibull statistics were used to describe the distribution of strengths. The influence on the Weibull strength of the many different processing parameters was found to be quantifiable in terms of cell porosity to a large extent. The results were validated with an independent set of measurements of strength and stiffness by uniaxial tension and the impulse excitation technique, respectively. For application of the finding in relation to the SOFC technology a mathematical frame to determine the optimal porosity of a SOFC system is presented.     

Compilation of mechanical properties for the structural analysis of solid oxide fuel cell stacks. Constitutive materials of anode-supported cells

The mechanical failure of one cell is sufficient to lead to the end of service of a solid oxide fuel cell (SOFC) stack. Therefore, there is growing interest in gaining knowledge on the mechanical properties of the cell materials for stress analysis.This study compiles available data from the literature on the mechanical properties of the most common materials used in intermediate-temperature anode-supported cells: nickel and yttria-stabilized zirconia (Ni–YSZ) anodes, YSZ electrolytes, yttria (YDC) or gadolinia-doped ceria (GDC) compatibility layers and lanthanum strontium manganite (LSM) or lanthanum strontium cobalt ferrite (LSCF) cathodes. The properties for the simulation of stresses, i.e. coefficient of thermal expansion (CTE), Young's modulus, Poisson's ratio, creep behaviour and strength are reported, with an emphasis on temperature and porosity dependence and the evolution upon aging or cycling when available. Measurements of our Ni(O)–YSZ anode material includes the CTE (oxidised and reduced state), Young's modulus and strength at room temperature (oxidised and reduced) and 1073 K (oxidised).     

An active heat-based restoring mechanism for improving the reliability of RF-MEMS switches

We propose an active mechanism to retrieve the functionality of RF-MEMS ohmic switches after stiction occurs. The mechanism exploits a micro-heater, embedded within the switch topology, to induce restoring forces on the stuck membrane (thermal expansion) when a current is driven through it. Our experimental investigations prove that driving a pulsed rather than a DC current into the heater, enables a successful release of the tested RF-MEMS stuck devices. The release of stuck RF-MEMS ohmic switches is demonstrated for a cantilever-type micro relay. The mechanism is suitable for a large variety of switch topologies, and it can be embedded with small changes and effort within most of the already existing RF-MEMS ohmic switches, increasing their reliability.