NMR shieldings from density functional perturbation theory: GIPAW versus all-electron calculations

We present a benchmark of the density functional linear response calculation of NMR shieldings within the Gauge-Including Projector-Augmented-Wave method against all-electron Augmented-Plane-Wave$+$local-orbital and uncontracted Gaussian basis set results for NMR shieldings in molecular and solid state systems. In general, excellent agreement between the aforementioned methods is obtained. Scalar relativistic effects are shown to be quite large for nuclei in molecules in the deshielded limit. The small component makes up a substantial part of the relativistic corrections.Comment: 3 figures, supplementary material include

Rupture of the arterial wall causes deflection in pressure time course during ex vivo balloon angioplasty

A relation between restenosis and arterial lesions resulting from balloon angioplasty has been suggested in literature. Nevertheless, it is unclear to what extent angioplasty-induced arterial wall lesions contribute to the occurrence of restenosis. One problem is that arterial ruptures cannot be detected during balloon inflation. This study describes a method to detect ruptures in the arterial wall, based on deflections observable in the development of the balloonpressure. We performed ex vivo angioplasty with constant strain rate on 28 human femoral artery segments, showing deflections in 21 cases. In 20 cases wall rupture was confirmed histologically. From seven cases not showing deflections, four showed intact wall at microscopy. These figures result in a selectivity of the proposed method of 87 ± 7% and a predictive value of the positive test of 95 ± 5%. We conclude that this method can enhance detection of arterial rupture during ex vivo angioplasty and may become important clinically

Prediction of core body temperature from multiple variables

This paper aims to improve the prediction of rectal temperature (Tre) from insulated skin temperature (Tis) and micro-climate temperature (Tmc) previously reported (Richmond et al., Insulated skin temperature as a measure of core body temperature for individuals wearing CBRN protective clothing. Physiol Meas 2013; 34:1531–43.) using additional physiological and/or environmental variables, under several clothing and climatic conditions. Twelve male (25.8±5.1 years; 73.6±11.5kg; 178±6cm) and nine female (24.2±5.1 years; 62.4±11.5kg; 169±3cm) volunteers completed six trials, each consisting of two 40-min periods of treadmill walking separated by a 20-min rest, wearing permeable or impermeable clothing, under neutral (25°C, 50%), moderate (35°C, 35%), and hot (40°C, 25%) conditions, with and without solar radiation (600W m−2). Participants were measured for heart rate (HR) (Polar, Finland), skin temperature (Ts) at 11 sites, Tis (Grant, Cambridge, UK), and breathing rate (f) (Hidalgo, Cambridge, UK). Tmc and relative humidity were measured within the clothing. Tre was monitored as the 'gold standard' measure of Tc for industrial or military applications using a 10cm flexible probe (Grant, Cambridge, UK). A stepwise multiple regression analysis was run to determine which of 30 variables (Tis, Ts at 11 sites, HR, f, Tmc, temperature, and humidity inside the clothing front and back, body mass, age, body fat, sex, clothing, Thermal comfort, sensation and perception, and sweat rate) were the strongest on which to base the model. Using a bootstrap methodology to develop the equation, the best model in terms of practicality and validity included Tis, Tmc, HR, and 'work' (0 = rest; 1 = exercise), predicting Tre with a standard error of the estimate of 0.27°C and adjusted r2 of 0.86. The sensitivity and specificity for predicting individuals who reached 39°C was 97 and 85%, respectively. Insulated skin temperature was the most important individual parameter for the prediction of Tre. This paper provides novel information about the viability of predicting Tc under a wide range of conditions, using predictors which can practically be measured in a field environment

Geophysical investigation and dynamic modelling of unstable slopes: case-study of Kainama (Kyrgyzstan)

The presence of massive Quaternary loess units at the eastern border of the Fergana Basin (Kyrgyzstan, Central Asia) makes this area particularly prone to the development of catastrophic loess earthflows, causing damages and injuries almost every year. Efficient disaster management requires a good understanding of the main causes of these mass movements, that is, increased groundwater pressure and seismic shaking. This paper focuses on the Kainama earthflow, mainly composed of loess, which occurred in 2004 April. Its high velocity and the long run-out zone caused the destruction of 12 houses and the death of 33 people. In summer 2005, a field survey consisting of geophysical and seismological measurements was carried out along the adjacent slope. By combination and geostatistical analysis of these data, a reliable 3-D model of the geometry and properties of the subsurface layers, as shown in the first part of the paper, was created. The analysis of the seismological data allowed us to point out a correlation between the thickness of the loess cover and the measured resonance frequencies and associated amplification potential. The second part of this paper is focused on the study of the seismic response of the slope by numerical simulations, using a 2-D finite difference code named FLAC. Modelling of the seismic amplification potential along the slope confirmed the results obtained from the seismological survey—strong amplifications at the crest and bottom of the slope where there is a thick loess cover and almost no amplification in the middle part of the slope. Furthermore, dynamic slope stability analyses were conducted to assess the influence of local amplifications and increased groundwater pressures on the slope failure. The results of the dynamic modelling, although preliminary, show that a combination of seismic and hydrologic origin (pore pressure build-up during the seismic shaking) is the most probable scenario responsible for the 2004 failur

A novel heteroditopic terpyridine-pincer ligand as building block for mono- and heterometallic Pd(II) and Ru(II) complexes

A palladium-catalyzed Stille coupling reaction was employed as a versatile method for the synthesis of a novel terpyridine-pincer (3, TPBr) bridging ligand, 4'-{4-BrC6H2(CH2NMe2)(2)-3,5}-2,2':6',2 ''-terpyridine. Mononuclear species [PdX(TP)] (X = Br, Cl), [Ru(TPBr)(tpy)](PF6)(2), and [Ru(TPBr)(2)](PF6)(2), synthesized by selective metalation of the NCNBr-pincer moiety or complexation of the terpyridine of the bifunctional ligand TPBr, were used as building blocks for the preparation of heterodi- and trimetallic complexes [Ru(TPPdCl)(tpy)](PF6)(2) (7) and [Ru(TPPdCl)(2)]-(PF6)(2) (8). The molecular structures in the solid state of [PdBr(TP)] (4a) and [Ru(TPBr)(2)](PF6)(2) (6) have been determined by single-crystal X-ray analysis. Electrochemical behavior and photophysical properties of the mono-and heterometallic complexes are described. All the above di- and trimetallic Ru complexes exhibit absorption bands attributable to (MLCT)-M-1 (Ru -> tpy) transitions. For the heteroleptic complexes, the transitions involving the unsubstituted tpy ligand are at a lower energy than the tpy moiety of the TPBr ligand. The absorption bands observed in the electronic spectra for TPBr and [PdCl(TP)] have been assigned with the aid of TD-DFT calculations. All complexes display weak emission both at room temperature and in a butyronitrile glass at 77 K. The considerable red shift of the emission maxima relative to the signal of the reference compound [Ru(tpy)(2)](2+) indicates stabilization of the luminescent (MLCT)-M-3 state. For the mono- and heterometallic complexes, electrochemical and spectroscopic studies (electronic absorption and emission spectra and luminescence lifetimes recorded at room temperature and 77 K in nitrile solvents), together with the information gained from IR spectroelectrochemical studies of the dimetallic complex [Ru(TPPdSCN)(tpy)](PF6)(2), are indicative of charge redistribution through the bridging ligand TPBr. The results are in line with a weak coupling between the {Ru(tpy)(2)} chromophoric unit and the (non)metalated NCN-pincer moiety

Endothermic salts integrated in impermeable suits do not reduce heat strain during exercise

Wearing impermeable garments during work inherently leads to heat strain, even in cold environments [1]. Phase change materials (mainly paraffin’s or salt [4]) may be used as a thermal buffer (e.g. [2]) to reduce initial heat stress. Salts can also be used to absorb sweat, which may enhance the cooling power from the skin. Recently, specific encapsulated salts utilising KSCN (potassium thiocyanate) have been developed that consume energy when the KSCN dissolves in water. The heat consumed when the KSCN (present inside 150 g of capsules containing 60% KSCN salt) dissolves in water is 22410 J (249 J/g * 60% * 150 g). When this solving takes place over a period of 30 minutes, the average power transfer is 12 W. One (1) g of KSCN-containing capsules absorbs close to 1 g of moisture. If we assume that 150 g sweat extra can be evaporated from the skin, this yields an extra cooling power of 182 W for 30 minutes. However this evaporated water from the skin is subsequently absorbed by the KSCN in the capsules. During this absorption from the gas phase, the condensation heat is released to the KSCN salt: about 182 W for 30 minutes. However, we hypothesise that this condensation heat will be partly transferred to the body and partly to the environment [3], providing a net benefit to the body. Thus, the total cooling effect due to the salt capsules is composed of two parts: • The cooling effect of about 12 W due to the heat consumption by the dissolving of the salts in water; • The cooling effect of maximal 182 W, which equals the difference between the evaporative heat and the condensation heat. The latter is generated in the salt capsules that transfer part of the heat to the environment. The overall cooling effect should therefore be in between 12 W and 194 W. The purpose of our study was to test the efficacy of a KSCN-based absorbing salt as a PCM for use within impermeable protective clothing. We tested the PCM during 20 min of moderate exercise in a hot (35°C, 40% relative humidity) environment, and hypothesized that thermal strain would be lower in the PCM compared to the non-PCM condition

Effects of cooling before and during simulated match play on thermoregulatory responses of athletes with tetraplegia

Objectives: Athletes with high level spinal cord injuries (tetraplegia) are under greater thermal strain during exercise than the able-bodied. The purpose of this study was to investigate the effectiveness of pre-cooling using an ice vest and the combination of pre-cooling and cooling during play using water sprays in athletes with tetraplegia. Design: Counter-balanced, cross-over design. Methods: Eight wheelchair rugby players with tetraplegia completed a 60 min intermittent sprint protocol (ISP) on a wheelchair ergometer in 20.2 °C ± 0.2 °C and 33.0% ± 3.1% relative humidity. The ISP was conducted on three occasions; no cooling (NC), pre-cooling with an ice vest (P) and pre-cooling with an ice vest and water sprays between quarters (PW). Gastrointestinal (Tgi) temperature, mean skin temperature (Tsk) and perceptual responses were measured throughout. Results: At the end of pre-cooling, the change in Tgi was not significantly different between conditions (P > 0.05) but the change in Tsk was significantly greater in P and PW compared to NC (P 0.05). Conclusions: Water spraying between quarters combined with pre-cooling using an ice vest lowers thermal strain to a greater degree than pre-cooling only in athletes with tetraplegia, but has no effect on simulated wheelchair rugby performance or perceptual responses

Thermoregulatory responses during competitive wheelchair rugby match play

The purpose of this study was to determine whether a player’s physical impairment or activity profile was related to the amount of thermal strain experienced during wheelchair rugby match play. 17 elite wheelchair rugby players played a competitive match, whilst activity profiles, measures of core and skin temperature, heart rate and perceptual responses were taken. Players were divided into 2 groups depending on their physical impairment: players with a cervical spinal cord injury, (n=10) or non-spinal related physical impairment (n=7). Total distance was lower (4 842±324 vs. 5 541±316 m, p<0.01, ES=2.2) and mean speed slower (1.13±0.11 vs. 1.27±0.11 m∙s−1, p<0.03, ES=1.3) in players with a spinal cord injury. Yet, the change in core temperature (1.6±0.4 vs. 0.7±0.3°C, p<0.01, ES=2.5) was significantly greater in players with a spinal cord injury. In conclusion, players with a spinal cord injury were under greater thermal strain during wheelchair rugby match play, as a result of their reduced heat loss capacity, due to their physical impairment and not because of their activity profile