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Crossed molecular beam scattering and quantum scattering calculations reveal the dynamical mechanisms underlying rotationally inelastic scattering for NO(A) + Kr.

Stereodynamic descriptions of molecular collisions concern the angular correlations that exist between vector properties of the motion of the participating species, including their velocities and rotational angular momenta. Measurements of vector correlations provide a unique view of the forces acting during collisions, and are a stringent test of electronic-structure calculations of molecular interactions. Here, we present direct measurement of the four-vector correlation between initial and final relative velocities and rotational angular momenta in a molecular collision. This property, which quantifies the extent to which a molecule retains a memory of its initial sense of rotation, or handedness, as a function of scattering angle, yields insight into the dynamics of a molecular collision. We report non-intuitive changes in the handedness for specific states and scattering angles, reproduced by classical and quantum scattering calculations. Comparison to calculations on different ab initio potential energy surfaces demonstrates this measurement’s exquisite sensitivity to the underlying intermolecular forces. Measurements of vector correlations provide insight into the forces acting during molecular collisions, and are a stringent test of electronic-structure calculations. Now, non-intuitive dynamics of molecular collisions have been revealed by measuring the correlation between the relative velocities of the colliders and the molecular rotational angular momentum—before and after the collision—for NO(A 2Σ+) + Ne.

In the context of reducing CO2 emissions and balancing energy supply and demand across the electricity grid, energy storage has become an important topic. Therefore, new energy policies are looking for more efficient and environmental friendly technologies. The aim of this research is to assist in the implementation of the renewable energies technologies and to improve the energy efficiency in well-known and established processes by recovering and storing heat. Moreover, the use of a recycled material as a storage media for thermal energy storage applications shows a more sustainable use of resources reducing at the same time the overall cost. In this research a novel composite, a recycled high density polyethylene (HDPE)/graphite(Cg) mixture, for medium temperature thermal energy storage application has been formulated and characterized. One common characteristic of polymers is their low thermal conductivities. This causes a slow thermal response when the PCM is used in high power applications. In this study the thermal conductivity properties of the HDPE/Cg were enhanced by the optimization of its manufacturing process and composition. Graphite content was added in different mass fractions into the PCM, and thermal properties were measured by means of Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC) and Laser Flash Analysis (LFA). The experimental results showed that the thermal conductivities are improved by the higher mass fraction of graphite. When the graphite content was in the ratio of 20 wt%, the thermal conductivity of the PCM increased from 0.51 W m−1 K−1 up to 1.31 W m−1 K−1. The secondary electron microscopy confirms a good homogeneity of the manufacturing process. Further chemical stability analysis was performed by means of charging and discharging processes. The cycled samples present good thermal property reliability at temperatures up to 250 °C.

Einleitung In diesem Beitrag werden Biomonitoring-Ergebnisse vorgestellt sowohl von Arbeitnehmern, die in der Produktion von Isocyanaten beschaftigt sind (Kollektiv 1), als auch von denen, die isocyanathaltige Produkte anwenden (Parkettleger; Kollektiv 2). Folgende Isocyanate werden betrachtet: 4,4-MDI (Diphenylmethandiisocyanat), 2,4- und 2,6-TDI (Diisocyanattoluole) und HDI (Hexamethylen-1,6-diisocyanat). Im Rahmen des Biomonitorings wurden in den Urinproben die entsprechenden Amine der Isocyanate, d. h. MDA, 2,4-TDA, 2,6-TDA und HDA, mittels GC/MS bestimmt. Daruber hinaus fanden bei der Parkettlegerstudie Luftmessungen statt.

Stereodynamic descriptions of molecular collisions concern the angular correlations that exist between vector properties of the motion of the participating species, including their velocities and rotational angular momenta. Measurements of vector correlations provide a unique view of the forces acting during collisions, and are a stringent test of electronic-structure calculations of molecular interactions. Here, we present direct measurement of the four-vector correlation between initial and final relative velocities and rotational angular momenta in a molecular collision. This property, which quantifies the extent to which a molecule retains a memory of its initial sense of rotation, or handedness, as a function of scattering angle, yields insight into the dynamics of a molecular collision. We report non-intuitive changes in the handedness for specific states and scattering angles, reproduced by classical and quantum scattering calculations. Comparison to calculations on different ab initio potential energy surfaces demonstrates this measurement's exquisite sensitivity to the underlying intermolecular forces.

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area verified the present biomonitoring method. The described method allows the simultaneous determination of the metabolites of hexamethylene diisocyanate (HDI), 2,4-toluenediamine and 2,6-toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and methylene diphenyl diisocyanate (MDI) in human urine. After acid hydrolysis the released amines, hexamethylenediamine (HDA), 2,4-, and 2,6-toluenediamine (TDA), isophorone diamine (IPDA) and 4,4′-methylenedianiline (4,4′-MDA) are extracted from urine, derivatised using heptafluorobutyric anhydride and quantified by NCI-GC-MS. The method was extensively validated and the reliability data were confirmed by independent laboratories, which have established and cross-checked the whole procedure Keywords: Hexamethylendiisocyanat; HDI; 2,4-Toluylendiisocyanat; 2,4-TDI; 2,6-Toluylendiisocyanat; 2,6-TDI; Isophorondiisocyanat; IPDI; Diphenylmethan-4,4′-diisocyanat; MDI; Hexamethylendiamin; HDA; 2,4-Toluylendiamin; 2,4-TDA; 2,6-Toluylendiamin; 2,6-TDA; Isophorondiamin; IPDA; 4,4′-Diaminodiphenylmethan; MDA; Urin; Biomonitoring; Analysen in biologischem Material; Gaschromatographie

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area verified the present biomonitoring method. The described method allows the simultaneous determination of the metabolites of hexamethylene diisocyanate (HDI), 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and methylene diphenyl diisocyanate (MDI) in human urine. After acid hydrolysis the released amines, hexamethylenediamine (HDA), 2,4-toluenediamine, and 2,6-toluenediamine (TDA), isophorone diamine (IPDA) and 4,4′-methylenedianiline (4,4′-MDA) are extracted from urine, derivatised using heptafluorobutyric anhydride and quantified by NCI-GC-MS. The method was extensively validated and the reliability data were confirmed by independent laboratories, which have established and cross-checked the whole procedure. Keywords: hexamethylene diisocyanate; HDI; 2,4-toluene diisocyanate; 2,4-TDI; 2,6-toluene diisocyanate; 2,6-TDI; isophorone diisocyanate; IPDI; methylene diphenyl diisocyanate; MDI; hexamethylenediamine; HDA; 2,4-toluenediamine; 2,4-TDA; 2,6-toluenediamine; 2,6-TDA; isophorone diamine; IPDA; 4,4′-methylene dianiline; MDA; urine; biomonitoring; analyses in biological materials; gas chromatography

β-Hydroxyethoxyacetic acid (HEAA) in urine The documentation presents the selective detection of β-hydroxyethoxyacetic acid (HEAA), which is considered to be the main metabolite of 1,4-dioxane and diethylene glycol, respectively. The urine sample to be analyzed is diluted with purified water and, after addition of the deuterated internal standard (D4-HEAA), acidified with concentrated hydrochloric acid and then extracted with ethyl acetate. An aliquot of the ethyl acetate phase is evaporated to dryness under a stream of nitrogen. The residue is derivatized by addition of N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and the bis-silylated β-hydroxyethoxyacetic acid is analyzed after electron impact ionization using GC–MS in the Selected Ion Monitoring (SIM) mode. Keywords: β-Hydroxyethoxyessigsaure; HEAA; Diethylenglycol; 2-Hydroxyethoxyessigsaure; Urin; Biomonitoring; 1,4-Dioxan; GC-MS; GC-HR-MS; Biologisches Monitoring

The ability of gas-surface dynamics studies to resolve the velocity distribution of the scattered species in the 2D sacattering plane has been limited by technical capabilities and only a few different approaches have been explored in recent years. In comparison, gas-phase scattering studies have been transformed by the near ubiquitous use of velocity map imaging. We describe an innovative means of introducing a surface within the electric field of a typical velocity map imaging experiment. The retention of optimum velocity mapping conditions was demonstrated by measurements of iodomethane-d3 photodissociation and SIMION calculations. To demonstrate the systems capabilities the velocity distributions of ammonia molecules scattered from a PTFE surface have been measured for multiple product rotational states., 8 pages, 5 figures, to be submitted to journal

This article has no abstract. Keywords: biomonitoring; 1,4-dioxane; diethylene glycol; β-hydroxyethoxyacetic acid; HEAA; urine; gas chromatography; mass selective detection; GC–MS; analysis in biological materials; occupational monitoring; analytical method; biomarker; metabolites

OBJECTIVE: Bladder cancer responds favourably to treatment and has a good survival rate, provided it is diagnosed at an early stage. Established methods exist for the early detection, however, their specificity and positive predictive value are not yet satisfactory. Innovative markers have been proposed, but still require validation in prospective studies. We provide a literature-based short overview on the currently available and some proposed markers for the early detection of bladder cancer and evaluate the need for validation in further studies. We further provide some first results of such a recently finished study in an occupational setting. MATERIAL AND METHODS: We conducted a prospective screening study over seven years in 1610 males with former occupational exposure to carcinogenic aromatic amines. Annual bladder cancer screening according to statutory requirements was offered. In addition to the regularly performed check for hematuria and urine cytology, the markers NMP22, UroVysion™ and survivin were performed in voided urine samples of the participants. Positive findings (not for survivin) were further followed through urethrocystoscopy. RESULTS AND CONCLUSIONS: A total of 7219 urine samples were screened. During the study period 16 incidental and 4 recurrent bladder tumours, thereof three papillomas, occurred in a total of 19 participants. 14 out of twenty tumours were marker-positive, and all but two were early stage findings. Cell-based markers (cytology, UroVysion™) und molecular markers (NMP22, survivin) were largely complementary, thus acting as a “multi-marker panel”. Eight of the tumours were identified by a positive cytology. Six tumours were not detected by any of the tumour markers. The results will be further evaluated through the inclusion of confounding factors, which have so far rarely been examined in other studies. This may lead to the development of tiered diagnostic strategies with the aim to reduce the number of invasive diagnostic procedures in the future.

The analytical method describes the specific determination of 3‐methyl‐5‐isopropylhydantoin (MIH), a hemoglobin adduct of N,N‐dimethylformamide. Following addition of 13C5,15N‐3‐methyl‐5‐isopropylhydantoin (13C5,15N‐MIH) as internal standard, isolated globin is subjected to acid hydrolysis for one hour at 110°C. After pH adjustment (pH 3 – 5) the hydrolysate is extracted twice with ethyl acetate. The combined extracts are washed with sodium hydrogen carbonate solution and dried under a stream of nitrogen. The residue is dissolved in ethyl acetate. An aliquot of the solution is analyzed using GC–MS. For calibration purposes, calibration standards are prepared in pooled globin. They are processed in the same way as the samples to be analyzed.

Oxytocin neurones of the rat supraoptic nucleus are osmoresponsive and, with all other things being equal, they fire at a mean rate that is proportional to the plasma sodium concentration. However, individual spike times are governed by highly stochastic events, namely the random occurrences of excitatory synaptic inputs, the probability of which is increased by increasing extracellular osmotic pressure. Accordingly, interspike intervals (ISIs) are very irregular. In the present study, we show, by statistical analyses of firing patterns in oxytocin neurones, that the mean firing rate as measured in bins of a few seconds is more regular than expected from the variability of ISIs. This is consistent with an intrinsic activity‐dependent negative‐feedback mechanism. To test this, we compared observed neuronal firing patterns with firing patterns generated by a leaky integrate‐and‐fire model neurone, modified to exhibit activity‐dependent mechanisms known to be present in oxytocin neurones. The presence of a prolonged afterhyperpolarisation (AHP) was critical for the ability to mimic the observed regularisation of mean firing rate, although we also had to add a depolarising afterpotential (DAP; sometimes called an afterdepolarisation) to the model to match the observed ISI distributions. We tested this model by comparing its behaviour with the behaviour of oxytocin neurones exposed to apamin, a blocker of the medium AHP. Good fits indicate that the medium AHP actively contributes to the firing patterns of oxytocin neurones during non‐bursting activity, and that oxytocin neurones generally express a DAP, even though this is usually masked by superposition of a larger AHP.

Oxytocin secreted by nerve terminals in the posterior pituitary has important actions for ensuring a successful outcome of pregnancy: it stimulates uterine contractions that lead to birth and it is essential in the milk‐ejection reflex, enabling milk to be expelled from the mammary glands into the mouths of suckling young. Oxytocin also has important actions in the brain: released from dendrites of neurones that innervate the posterior pituitary, oxytocin auto‐excites the neurones to fire action potentials in co‐ordinated bursts, causing secretion of pulses of oxytocin. Central oxytocin actions are blocked by an oxytocin antagonist given into the brain and, consequently, milk transfer stops. Systemic peptide oxytocin antagonist (atosiban) treatment is used clinically in management of pre‐term labour, a major obstetric problem. Hence, it is important to know whether an oxytocin antagonist given peripherally can enter the brain and interfere with central oxytocin actions. In the present study, we tested F792, a peptide oxytocin antagonist. In urethane‐anaesthetised suckled rats, we show that the mammary gland responsiveness to oxytocin is blocked by i.v. injections of 7 μg/kg of F792, and the milk‐ejection reflex is blocked when F792 is given directly into the brain at a dose of 0.2 μg. To critically test whether F792 given systemically can enter the brain, we recorded the suckling‐ and oxytocin‐induced burst‐firing of individual antidromically identified oxytocin neurones in the paraventricular nucleus. Given systemically at 100 μg/kg i.v., F792 acted only peripherally, blocking the milk‐ejecting actions of oxytocin, but not the burst‐firing of oxytocin neurones during suckling (n = 5 neurones in five rats). Hence, this peptide oxytocin antagonist does not enter the brain from the circulation to interfere with an essential oxytocin function in the brain. Furthermore, the functions of oxytocin in the brain evidently cannot be explored with a systemic peptide antagonist.

House dust and airborne particles (PM) were sampled before (T1) and 1 day (T2), 4-6 months (T3) as well as 10-12 months (T4) after a pest control operation (PCO). Cyfluthrin was applied in 11, cypermethrin in 1, deltamethrin in three and permethrin in four interiors. The pyrethroid concentrations in house dust and PM were measured by GC/MS with a detection limit for all pyrethroids of 0.5 mg/kg house dust and of 1 ng/m3 PM for deltamethrin and permethrin and 3 ng/m3 PM for cyfluthrin and cypermethrin. A general background concentration of permethrin (95th percentile: 5.9 mg/kg) and cyfluthrin (95th percentile: 34.9 mg/kg) in house dust was found. In general, an appropriately performed PCO lead to an increase of pyrethroids in house dust as well as in PM, in some cases up to 1 year after application. One day after the application the cyfluthrin concentration increased significantly from 0.25 (T1) to 33.8 mg/kg house dust (T2) and up to 4.9 ng/m3 in PM. The permethrin concentration increased significantly from 4.3 to 70 mg/kg in house dust and up to 18.1 ng/m3 in PM, deltamethrin increased to 54.5 mg/kg and 20.8 ng/m3 and cypermethrin to 14 mg/kg and 45.7 ng/m3. Thereafter a continuous decrease could be observed during the time course of 1 year. After 1 year the permethrin concentration in house dust was still 1/5 of the T2 concentration, whereas for cypermethrin and cyfluthrin only 1/14 and 1/23 of the T2 concentration were found. Deltamethrin was not detected at all after T2. Moreover, the data of this study showed significant, positive correlations between pyrethroids in house dust and in airborne particles especially one day after PCO.

The 1/2+ ground state and a 11/2- isomer of very neutron-deficient isotope 143Dy were produced by irradiation of an enriched target of 106Cd with 40Ca and studied by using a helium-jet fast tape-transport system in combination with proton-γ, X-γ and γ-γ coincidence measurements. A simple ( EC + β+) decay scheme of 143mDy with a half-life of 3.0(3) s and a tentative ( EC + β+) decay scheme of 143gDy with a half-life of 5.6(10) s are proposed. As a by-product, the 347- and 545-keV γ transitions in 138Sm following the β-delayed proton emission of 139Gd decay and the 323-keV γ transition in 139Eu following the β-delayed proton emission of 140Tb decay could be observed for the first time.

A prospective epidemiological study with respect to pyrethroid exposure was carried out combining clinical examination, indoor monitoring and biological monitoring. The results of the biological monitoring are presented. Biological monitoring was performed in 57 persons before (T1) as well as 1 day (T2), 3 days (T3), 4-6 months (T4), and 10-12 months (T5) following a pest control operation (PCO) with pyrethroid containing products such as cyfluthrin, cypermethrin, deltamethrin or permethrin. Pyrethroids in blood were measured by GC-ECD. The respective metabolities cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (DBCA), 3-phenoxybenzoic acid (3-PBA) and fluorophenoxybenzoic acid (FPBA) were measured in urine using GC/MS. For all cases the concentrations of pyrethroids in blood were found to be below the detection limit of 5 micrograms/l before and after the PCO. With a detection limit of 0.2 microgram/l of the investigated metabolites, the percentage of positive samples were 7% for cis-DCCA, 3.5% for trans-DCCA and 5.3% for 3-PBA before PCO. One day after PCO (T2) the percentage of positive samples increased remarkably for cis-DCCA (21.5%), trans-DCCA (32.1%) and 3-PBA (25%) showing significantly increased internal doses as compared to pre-existing values. This holds also true for T3, whereas at T4 and T5 the significant increase was no more present. FPBA and DBCA concentrations were below the respective detection limit before PCO and also in most cases after PCO. In 72% of the subjects the route of pyrethroid uptake (measured by determining the DCCA isomeric ratio) was oral/inhalative and in 28% it was dermal. Based on the biological monitoring data it could be shown that appropriately performed pest control operations lead to a significant increase of pyrethroid metabolite concentration in the early phase (1 and 3 days) after pyrethroid application as compared to the pre-exposure values. However, evaluated metabolite concentrations 4-6 months after PCO did not exceed values of published background levels.

The β-delayed proton precursor 149Yb was synthesized in the reaction 112Sn(40Ca, 3n) and identified by using a proton-gamma coincidence measurements in combination with a helium-jet fast tape transport system. Its β-delayed proton spectrum was observed. The half-life of 149Yb was determined to be 0.7±0.2 s. The 253, 101, and 365 keV γ transitions in 147Dy, following β-delayed proton emission of 148Ho decay, were reported for the first time.

The ultrastructures of the upper surface layer of rat articular cartilage were studied with our "in vivo cryotechnique" followed by freeze-substitution method for scanning electron microscopy (SEM) or transmission electron microscopy (TEM). Rat hip or knee articular cartilage was quickly frozen by the in vivo cryotechnique with liquid isopentane-propane cryogen (-193 degrees C), and surface areas of some frozen specimens were freeze-fractured with a scalpel in liquid nitrogen. They were freeze-substituted and freeze-dried, ion-sputtered, and then observed in SEM. Other frozen specimens were routinely freeze-substituted and embedded in epoxy resin for TEM. Many globular structures were detected in the thick upper surface layer that had not been revealed by the conventional fixation methods. Their sizes were reduced by Triton X-100 treatment, and their localization was also detected in synovial fluid, as revealed by SEM. Such globular lipid-like structures in the upper surface layer of hip or knee articular cartilage might contribute to joint lubrication.

When the natural zeolite ceramsite (NZC) is added to cellular concrete, using the natural-zeolite powder as a gas carrier, natural-zeolite ceramsite cellular concrete is formed. It is a new type of concrete. Its compressive strength at 28 days is 12–14 MPa, while its density is 900–1000 kg/m3. It has a double capillary structure of cellular concrete and ceramsite. The NZC absorbs water and its capillaries are full of water when the concrete is mixed. But after concrete hardening, the capillaries in the NZC undergo ‘self-vaccumization’ owing to dehydration, so that the adhesion between the ceramsite and cellular concrete is increased.

The modern environmental awareness leads to the realisation that the human metabolism is stressed by a huge number of chemical substances. Generally, these background exposures, consisting predominantly from natural and partly from industrial as well as life style sources, are tolerated without any adverse effects. Pesticides are chemicals intentionally introduced to the environment and have become necessities in modern agriculture as well as in indoor pest control. Their residues, therefore, is attracting more and more concern. For the majority of pesticides neither occupational nor environmental medical risk evaluations are so far available. Therefore, at the moment the occupational as well as the environmental supported preventive concept may only be achieved, if binding instructions upon experience and guide values are developed for the assessment of the individual risk of handling pesticides. In the occupational and environmental pesticide prophylaxis the ubiquitous background exposure levels in consideration with individual susceptibility factors should be recommended as provisional biological tolerance guide values. The suitability of this guide values concept for pesticides is demonstrated by determining the background exposure and the biomarkers of susceptibility of 250 unexposed persons as well as of more than 1200 occupationally exposed persons. As a result, a significant dependence of their health fidelity from the background exposure profile impressed on the individual polymorphism of the key enzymes was observed. Especially, the cumulative adducts of electrophilic substances and their metabolites with macromolecules like HSA and Hb turned out to be sensitive markers for the capacity of the individual metabolic rate. For alkylating and arylating pesticides the observed interindividual susceptibility to their adverse effects depends on the variability of the individual 'toxifying' and 'detoxifying' metabolic rates. Until scientific evaluation of official biological tolerance values for pesticides is carried out, it is advisable for risk prophylaxis to orientate the assessment of any individual tolerable stress and strain from pesticides to the synergism between background exposure, life style factors and biomarkers of specific susceptibility. They may be examined by a monitoring of conjugates and polymorphism marked by the individual metabolic rate. The monitoring and surveillance of pesticide exposures is mainly introduced by the recommendation of tolerable biological values from the reference value concept. This concept is an essential contribution to an objective risk discussion with regard to individual stress and strain profiles in environmental exposure scenarios.

The aim of this study was to find a suitable biomarker for pyrethroid adverse effects. It was shown that there is a correlation between the half-life time (t(1/2)) of pyrethroids in plasma and the clinical findings. We hypothized that this finding indicates an interindividual different amount of total esterase activity or even a polymorphism. By in vitro experiments it was demonstrated that pyrethroids are cleaved by carboxylesterases. After it turned out that carboxylesterase activity in human plasma is too low for detection, a method for specific determination of carboxylesterase activity in human isolated lymphocytes was developed. As a substrate for carboxylesterase activity, cyfluthrin was added to the lymphocyte suspension. As a proof for cyfluthrin degradation by carboxylesterases the produced hydrocyanic acid was determined by GC/MS. First hints for interindividual differences in carboxylesterase activity in lymphocytes were found.