The effects of disc degeneration and muscle dysfunction on cervical spine stability from a biomechanical study

Disc degeneration and muscle dysfunction are common spinal degenerations in the elderly. This in vitro study was carried out to investigate the effects of these two degenerative changes on spinal stability. The stability of nine porcine cervical spines (C2-T1) with mechanically simulated cervical muscles (sternocleidomastoid (SCM), splenius capitis (SPL), semispinalis capitis (SSC)) was tested before and after experiment-induced disc degeneration. The patterns of muscle recruitments included: no muscle recruitment, normal recruitment of SCM/SPL/SSC, and SCM/SPL/SSC muscle dysfunctions. The neutral zone (NZ) and the range of motion (ROM) in the sagittal plane were measured to determine spinal stability. The results showed that the NZ and the ROM of a degenerative spine were larger than those of an intact spine under no muscle recruitment, but not under muscle recruitments. For both intact and degenerative spines, the NZ and the ROM were greatest under no muscle recruitment, followed by SSC dysfunction, SCM dysfunction, and SPL dysfunction, and smallest under normal muscle recruitment. In conclusion, muscle recruitments stabilize both intact and degenerative cervical spines, while dysfunctional muscles do not maintain stability efficiently as normal muscles do. Thus, spinal stability is more significantly affected by muscle dysfunction than by disc degeneration. Muscle training is suggested for the elderly with spinal degeneration to improve stability.     

High efficiency multichannel collimator for structural studies of liquids and low-Z materials at high pressures and temperatures

A high efficiency multichannel collimator (MCC) device has been developed at the high pressure beamline ID27 of the European Synchrotron Radiation Facility to drastically reduce the x-ray background from the sample environment in the Paris-Edinburgh press. The main technical difficulty, which resides in the minimum slits size achievable using the classical mono-bloc design, has been resolved using an original concept based on a set of independent slits. Then, a very small slit size of 50 μm was manufactured resulting in a great improvement of the signal to background ratio. In addition, the transfer function of the MCC has been measured using the x-ray diffusion signal of a metal doped glass and efficiently applied to correct the raw data. The potential of this new device is illustrated in two challenging examples: iron-sulfur liquid structures and C(60) polymerization process at high pressure and high temperature.     

小浪底大坝防渗墙和灌浆工程特殊处理技术

本文介绍了在小浪底水利枢纽工程建造中地下混凝土防渗墙体系的不同施工技术。大坝的地下截渗和上游围堰防渗灌浆采用了不同的施工，包括岩石灌浆、帷幕灌浆、冲积地层中建造地下混凝土防渗墙和高压旋喷灌浆等技术。特别要说明的是在建造地下混凝土防治在墙体系中采用了许多新技术，进行了多项的技术革新，缩短了施工工期，解决了河床底底部地形轮廓条件下清的施工技术难题。     

Benefits, limitations and uncertainty of in situ spectrometry.

In situ spectrometers are comparable robust instruments and can be operated long term with relatively low maintenance demand. The decisive factor for their applicability is the development of a medium and installation location specific correlation model, which estimates the concentration of the requested target parameter from the measured absorption values. In some cases it might turn out, that the development of a single site specific correlation model is not sufficient, due to frequent and substantial variations of the (waste) water composition.In order to assess the total uncertainty of in situ spectrometry, a comprehensive lab test was carried out. It includes a detailed investigation of the uncertainty of CODreference methods (DIN and small tube tests), a precision analysis of the absorption spectra and the impact of those two factors on the total uncertainty of the COD(EQ) correlation model.     

Comparison of and uncertainties in raw sewage COD measurements by laboratory techniques and field UV-visible spectrometry.

A comprehensive investigation of the uncertainty of different COD analysis methods (DIN, small tube tests (STT) and UV-visible spectrometry methods) has been carried out on potassium hydrogen phthalate standard solutions and raw sewage samples from a large wastewater treatment plant. The UV-visible method allows estimating COD equivalent concentration from the measured absorption spectra by means of site specific regression and correlation functions. CODdin and CODstt methods showed equivalent global results but specific calibration relationships are necessary when high accuracy is required. The CODstt method is suitable for immediate COD analysis in the field. Sub-sampling is the main source of uncertainty. Spectrometry is able to estimate CODeq with an uncertainty of the same order of magnitude as the uncertainty in CODdin.     

Effect of Composition and Stirring on the Grain Structure of Aluminium Alloys solidified in Ingots

Abstract

Solidification experiments have been performed on a series of industrial aluminium alloys in a rectangular vertical ingot mould, in which an electromagnetic linear motor activated a recirculating flow. Results include macrographs, grain size measurements, and high resolution temperature records on 14 thermocouples. The refinement effect is clearly demonstrated. It is strong when stirring changes from zero to some moderate level, then its increment decreases asymptotically. In most of the temperature records, the recalescence behaviour due to the formation of equiaxed crystals can be followed in detail. Under good stirring conditions, equiaxed crystallisation starts simultaneously in all the volume elements and all of them follow the same thermal history, which explains the very good uniformity in grain structure. Non-uniform or coarse grain structures which are observed when stirring conditions are poor can be correlated to dissimilarities in the thermal history of the different volume elements. A theoretical model explains these observations and allows the effects of stirring and of composition on the equiaxed grain size to be predicted.     

Rennet-induced gelation of calcium and phosphate supplemented skim milk subjected to CO2 treatment

A Doehlert design was performed to study the effect of calcium and phosphate supplementation at 0 to 25 mmol/kg and 0 to 16 mmol/kg, respectively, on the rennet gelation of reconstituted skim milk subjected to pH-reversible CO(2) acidification. Supplemented reconstituted skim milk samples were acidified to pH 5.80 by the addition of CO(2) under pressure and depressurized under vacuum to restore the initial pH value. The second-order polynomial models satisfactorily predicted the effect of salt addition on the micellar molar Ca:P ratio and the average diameter of the casein micelles, whereas only trends were used in the analysis of the rennet-clotting behavior of salt-supplemented, CO(2)-treated milk. Whether added Ca was the most determinant factor on the micellar molar Ca:P ratio, added Pi (a mixture of Na(2)HPO(4) and NaH(2)PO(4)) was the most determinant factor on the other responses studied, and its effect was most pronounced when Ca was simultaneously added. By comparison with control samples, changes observed in this study were essentially due to salt supplementation and not to the CO(2) treatment. Therefore, this CO(2) treatment could be considered as an entirely reversible treatment rather than only pH-reversible, and predictions might be applied to untreated milk. In the case of Ca-supplemented milk, the micellar molar Ca:P ratio increased, the average micellar diameter decreased, and the rennet-clotting properties were improved, whereas opposite effects were observed upon Pi supplementation. Since modification of the micellar molar ratio is the result of change in the chemical composition of micellar calcium phosphate, the effect of calcium and phosphate supplementation on the rennet clotting of milk was found to be also dependent on the nature of the interaction between caseins and colloidal calcium phosphate.     

Fat volatiles tracers of grass feeding in sheep

Volatile compounds were analysed in subcutaneous fat from lambs raised and finished on grass (GG); raised and finished on concentrates (SS); raised on grass and finished on concentrates for a long (GS1) or a short (GS2) period. Whereas 3-methylindole (skatole), a compound that has been described as a good discriminator of grass feeding, was unaffected by the diet (P>0.05), 2,3-octanedione was lower (P<0.01) in the fat from animals that spent a period in stall with a concentrate diet than in those finished on grass. Among the 20 monoterpenes detected, only p-cymene was affected by the treatment, being higher (P<0.05) in the fat from animals raised and finished on grass (GG) than in the other treatments. Eight among the 13 detected sesquiterpenes were affected by the diet treatment. In particular β-caryophyllene, not detected in the fat from animals raised and finished on concentrates (SS group), was at basal levels in the animals raised on pasture and finished for different durations on concentrates (GS1 and GS2 treatments) and was present at high levels in the animals raised and finished on grass (P<0.0005). From a factorial discriminant analysis, four of the 33 terpenes detected discriminated perfectly those animals raised and finished on pasture (GG) from all the other groups (SS, GS1, GS2).     

Impact of a pulsed electric field on damage of plant tissues: effects of cell size and tissue electrical conductivity

Efficiency of pulsed electric field (PEF) induced permeabilization at 293 K in selected fruit and vegetable plant tissues (apple, potato, carrot, courgette, orange, and banana) at electric field strength (E) of 400 V·cm(-1), 1000 V·cm(-1) and pulse duration (t(p)) of 1000 μs was studied experimentally. The mean cell radius (〈r〉) was within 30 to 60 μm, and the ratio of electrical conductivities of the intact and damaged tissues (σ(i)/σ(d)) was within 0.07 to 0.79 for the studied tissues. Electroporation theory predicts higher damage for tissue with larger cells; however, the direct correlation between PEF damage efficiency and size of cell was not always observed. To explain this anomaly, a theoretical Monte Carlo model was developed and checked for parameters typical for potato tissue. The model showed a strong dependence of PEF damage efficiency and power consumption (W) on σ(i)/σ(d) ratio. The optimum value of electric field strength (E(opt)) was an increasing function of σ(i)/σ(d), and plant tissues with high σ(i)/σ(d) ratio (σ(i)/σ(d) ≈ 1) required application of a rather strong field (for example, E(opt) ≈ 3000 V·cm(-1) for σ(i)/σ(d) ≈ 0.8). However, the PEF treatment at a lower field (E ≈ 400 V·cm(-1)) allowed regulation of the selectivity of damage of cells in dependence of their size. A good qualitative correspondence between experimental data and simulation results were observed.     

Pitfalls and modelling inconsistencies in computational radiation dosimetry: lessons learnt from the QUADOS intercomparison. Part I: Neutrons and uncertainties

The QUADOS EU cost shared action conducted an intercomparison on the usage of numerical methods in radiation protection and dosimetry. The eight problems proposed were intended to test the usage of Monte Carlo and deterministic methods by assessing the accuracy with which the codes are applied and also the methods used to evaluate uncertainty in the answer gained through these methods. The overall objective was to spread good practice through the community and give users information on how to assess the uncertainties associated with their calculated results.