Long-term stability of hydroxyapatite bone phantoms for the calibration ofx-ray fluorescence spectrometry-based systems of bone lead and strontium quantification.

Hydroxyapatite (HAp) phantoms have been proposed as an alternative to plaster of Paris (poP) phantoms for the calibration of x-ray fluorescence-based systems for thequantification of bone lead and strontium which employ a coherent normalization procedure. The chemical composition of the material becomes critical in the calculation, or omission, of the coherent correction factor (CCF) required in this normalization procedure. This study evaluated the long-term chemical stability of HAp phantoms.

The Therapeutic Value of Hydralazine in Reducing Inflammatory Response, Oxidative Stress, and Mortality in Animal Sepsis: Involvement of the PI3K/AKT Pathway.

Sepsis is an amplified systemic immune-inflammatory response produced by a microorganism, which involves activation of inflammatory cytokine signaling pathways and oxidative stress. A variety of studies have shown that hydralazine (HDZ) has potent antioxidant and anti-inflammatory proprieties. Therefore, we hypothesize that HDZ can improve the clinical outcome of sepsis.

Martial arts technique for control of severe external bleeding.

Objectives: Haemorrhage control is a critical component of preventing traumatic death. Other than the battlefield, haemostatic devices, such as tourniquets or bandages, may not be available, allowing for significant avoidable blood loss. We hypothesised that compression of vascular pressure points using a position adapted from the martial art of Brazilian Jiu-Jitsu could be adapted to decrease blood flow velocity in major extremity arteries.

Assessment of the effect of strontium, lead, and aluminum in bone on dual-energy x-ray absorptiometry and quantitative ultrasound measurements: A phantom study.

Purpose: Dual-energy X-ray absorptiometry (DXA) is the gold standard technique to measure areal bone mineral density (aBMD) for the diagnosis of osteoporosis. Because DXA relies on the attenuation of photon to estimate aBMD, deposition of bone-seeking metallic elements such as strontium, lead, and aluminum that differ in atomic numbers from calcium can cause inaccurate estimation of aBMD. Quantitative ultrasound (QUS) is another technique available to assess bone health by measuring broadband ultrasound attenuation (BUA), speed of sound (SOS), and an empirically derived quantity called stiffness index (SI).

The feasibility of in vivo detection of lanthanum using a Am K x-ray fluorescence system.

Objective: Lanthanum (La) is commonly used in phosphate binders in the form of lanthanum carbonate in patients with end-stage kidney disease undergoing hemodialysis treatments. With this administration, there is the potential for La storage in the body with bone being the main site of concern. However, the long-term effects of residual La in the body on bone health are not yet known.

Calibration of the I-induced x-ray fluorescence spectrometry-based system of in vivo bone strontium determinations using hydroxyapatite as a phantom material: a simulation study.

Objective: The calibration of in vivo x-ray fluorescence systems of bone strontium quantification, based on I excitation, is dependent on a coherent normalization procedure. Application of this procedure with the use of plaster of Paris (poP) as a phantom material requires the application of a coherent conversion factor (CCF) to make the calibration functions transferable between the phantom material and human bone. In this work we evaluate, with the use of Monte Carlo simulation, the potential benefit of employing a newly developed hydroxyapatite phantom material into the calibration protocol.

Technical Note: Bone mineral density measurements of strontium-rich trabecular bone-mimicking phantoms using quantitative ultrasound.

Purpose: Bone quantity, as determined by the current gold standard, dual energy X-ray absorptiometry (DXA), through measured areal bone mineral density (aBMD), is subject to positive biases if bone strontium levels are high. This is of particular concern for populations administered strontium-based compounds for the treatment of osteoporosis. This study investigated the dependence of bone mineral density (BMD) determinations, and associated ultrasound-determined indices, obtained by quantitative ultrasound (QUS), on bone strontium content using a new generation of trabecular bone-mimicking phantoms.

Pure hydroxyapatite phantoms for the calibration of in vivo X-ray fluorescence systems of bone lead and strontium quantification.

Plaster of Paris [poP, CaSO4·(1)/(2) H2O] is the standard phantom material used for the calibration of in vivo X-ray fluorescence (IVXRF)-based systems of bone metal quantification (i.e bone strontium and lead). Calibration of IVXRF systems of bone metal quantification employs the use of a coherent normalization procedure which requires the application of a coherent correction factor (CCF) to the data, calculated as the ratio of the relativistic form factors of the phantom material and bone mineral.

[Adult vaccination coverage: surveys in four populations - Isère (France), 2002-2003].

In order to assess their vaccination policy, the public health authorities in Isère (France) conducted several surveys to determine the vaccination coverage rate among adults. In France, the current state of knowledge in this area is limited. Four separate surveys were conducted in 2002-2003: (1) a telephone survey of 976 adults, 18% of whom had vaccination certificates; (2) a survey of 44 general practitioners (805 patients); (3) a survey of occupational health centers (82 practitioners and 1,119 employees); and (4) a survey of 1,214 patients vaccinated at the international vaccination center in Grenoble (France).

Application of extrapolation chambers in low-energy X-rays as reference systems.

Extrapolation chambers are instruments designed to measure doses of low-energy radiations, mainly beta radiation. In this work, a commercial extrapolation chamber and a homemade extrapolation chamber were applied in measurements using standard radiotherapy X-ray beams. Saturation curves and polarity effect as well as short- and medium-term stabilities were obtained, and these results are within the recommendations of the International Electrotechnical Commission (IEC).

Self-assembly of chiral trans-cyclobutane-containing β-dipeptides into ordered aggregates.

Two chiral synthetic β-dipeptides have been constructed, one with two trans-cyclobutane residues and the other with one trans and one cis fragment, 1 and 2, respectively, and investigated to get insight into the non-covalent interactions responsible for their self-assembly to form ordered aggregates, as well into parameters such as their morphology and size. Experimental evidence of the formation of these assemblies was provided by spectroscopy, microscopy and X-ray diffraction experiments that suggest the formation of nanoscale helical aggregates. This process involves a conformational change in the molecules of each dipeptide with respect to the preferred conformation of the isolated molecules in solution.

Aluminium and strontium in calcium supplements and antacids: a concern to haemodialysis patients?

Trace elements, most notably aluminium and strontium, have been noted for their role in the development of secondary bone disorders in haemodialysis patients. Due to the large dosages of calcium required for the maintenance of dialysis patients, this study investigated whether the source of calcium chosen for supplementation, including the form of administration (i.e.

A deep tetranuclear metallo-cavitand with bis(aryl) palladium bridges.

A neutral metallo-cavitand based on cis bis-perhaloaryl Pd(II) bridges co-ordinated at the corners of a deep calix[4]arene. Both the metallo-cavitand and its inclusion complexes with other calix[4]arenes were investigated by means of (1)H and (19)F NMR experiments.

Folding and self-assembling with beta-oligomers based on (1R,2S)-2-aminocyclobutane-1-carboxylic acid.

Improved methodologies are provided to synthesize (1R,2S)-2-aminocyclobutane-1-carboxylic acid derivatives and their incorporation into beta-peptides of 2-8 residues bearing different N-protecting groups. The conformational analysis of these oligomers has been carried out by using experimental techniques along with theoretical calculations. This study shows that these oligomers adopt preferentially a strand-type conformation in solution induced by the formation of intra-residue six-membered hydrogen-bonded rings, affording cis-fused [4.

Prevalence of eight-membered hydrogen-bonded rings in some bis(cyclobutane) beta-dipeptides including residues with trans stereochemistry.

Three new bis(cyclobutane) beta-dipeptides have been synthesized from appropriate derivatives of cis- and trans-2-aminocyclobutane-1-carboxylic acid, respectively. The predominance of eight-membered hydrogen-bonded rings has been manifested for (trans,trans)- and (trans,cis)-beta-dipeptides while the formation of six-membered rings is preferred for the (cis,trans)- beta-dipeptide similarly to the previously described (cis,cis)-diastereomer.

Characterization of the three major polymorphic forms and liquid state of tristearin by Raman spectroscopy.

Raman spectroscopy was used to distinguish the differences in the molecular organization of the alpha, beta' and beta polymorphs, as well as the liquid state, of tristearin with focus placed on the C=O, C-H and C-C Raman-active stretching regions. The ester carbonyl stretching region permitted polymorphic discrimination due to significant differences in the number of modes, their relative frequencies and their full-widths at half-maximum. In the liquid state, the absence of obvious signatures in this region indicated that many local micro-environments likely exist about the ester carbonyl of molten tristearin.

Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy.

The conformational and thermodynamic behavior of five monoacid saturated triglycerides (TGs) before, during, and above the beta polymorph --> liquid phase transition was studied using Raman spectroscopy. The Raman ratio I[upsilon(s)(CH(2))]/I[upsilon(as)(CH(2))], used to identify intramolecular order about TG hydrocarbon chains, demonstrated that a single conformation, geometry and symmetry existed in liquid-state TGs. The Raman ratio I(1080)/I(1130), used to determine the intermolecular order/disorder about the hydrocarbon chains and relative trans/gauche content, remained constant for TGs in the crystalline state, but steadily increased as a function of temperature in the liquid state.

A new packing motif for para-sulfonatocalix[4]arene: the solid state structure of the para-sulfonatocalix[4]arene D-arginine complex.

The solid-state structure of the complex of para-sulfonatocalix[4]arene with d-arginine, contains a water channel diagonal to a zigzag bilayer of the host, within the bilayer six crystallographically independent molecules of arginine are present, four being included in the calix cavities.

Haemolytic properties of some water-soluble para-sulphonato-calix-[n]-arenes.

In this paper, we describe the haemolytic effect of parent para-sulphonato-calix-[n]-arenes and their derivatives bearing one pendant group at the lower rim of calix-arene towards human erythrocytes. A maximum of 30% of haemolysis has been observed for para-sulphonato-calix-[8]-arene for a concentration of 200 mM representing 300 g of calix-arene per liter of human blood, para-sulphonato-calix-[4]-arene and para-sulphonato-calix-[6]-arene show much lower haemolytic effects, 0.5 and 8%, respectively at 200 mM concentration.

The structure of a self-assembled calixarene aqua-channel system.

The crystal structure of the complex 12.calix-[4]-arene dihydroxyphosphonic acid, 12.propane diammonium, 12.

Para-acyl-calix-arene based solid lipid nanoparticles (SLNs): a detailed study of preparation and stability parameters.

The preparation and stability parameters of para-acyl-calix[4]arene based solid lipid nanoparticles (SLNs) have been investigated. Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) show a mean particle size of 130 nm. In terms of preparation parameters, using the solvent displacement method, the nature and the volume of the organic solvent, the concentration of the amphiphile and the presence of a co-surfactant in the organic phase have been shown to affect significantly the size of the produced SLNs.

Gallic esters of sucrose as efficient radical scavengers in lipid peroxidation.

Three tests of increasing complexity were used to assess the antioxidant activity of five synthetic gallic esters of sucrose bearing 3, 6, 7, or 8 galloyl units. In addition, two of these compounds had 1 or 2 hydrocarbon (C10-C12) acyl chains. Reaction with the DPPH radical led to the evaluation of the number of radicals trapped per galloyl unit n (3-4), as well as the apparent second-order rate constant for H atom donation k (1200-1500/M/s).