Reliability of a handgrip test for evaluating heart rate and pressor responses in multiple sclerosis

PURPOSE: The purpose of this study was to determine the test-retest reliability of an isometric handgrip exercise protocol designed to evaluate heart rate and arterial pressure responses in individuals with multiple sclerosis (MS). METHODS Three males and eleven females, aged 24 through 51, performed isometric handgrip contractions at 30% of maximal voluntary contraction (MVC) to the point of fatigue (defined as inability to maintain the target force for three consecutive seconds). During this exercise, rate of perceived exertion (RPE) was recorded every 30 s. Heart rate and beat-to-beat systolic, diastolic, and mean arterial pressures were recorded continuously throughout the duration of exercise. Surface EMG was monitored continuously via loudspeaker to provide feedback on extraneous muscular activity. Each subject performed three trials. A repeated measures ANOVA was used to calculate interclass reliability estimates for each dependent variable. RESULTS: Reliability estimates for MVC and time to fatigue were 0.98 and 0.84, respectively. Reliability estimates for the following dependent variables at the point of fatigue were: RPE, 0.90; delta HR, 0.97; delta systolic pressure, 0.92; delta diastolic pressure, 0.87; and delta MAP, 0.88. CONCLUSIONS: We conclude that this isometric handgrip protocol is a reliable method for evaluating heart rate and blood pressure responses in MS patient.     

Time-gated transillumination of objects in highly scattering mediausing a subpicosecond optical amplifier

We have developed an optical system that simultaneously selects and amplifies photons in a time window of less than 10 ps. This new subpicosecond optical amplifier allowed us to realize one-dimensional images of a striped pattern with a spatial resolution of 200-μm through a 30-mm liquid scattering medium. Monte Carlo simulations were performed to study the relative importance of parameters characterizing the medium and the time-gated amplifying system in relation to the image sharpness. The potential application of this system in medical imaging is discussed     

A comparison of five heuristics for the multiple depot vehicle scheduling problem

Given a set of timetabled tasks, the multi-depot vehicle scheduling problem consists of determining least-cost schedules for vehicles assigned to several depots such that each task is accomplished exactly once by a vehicle. In this paper, we propose to compare the performance of five different heuristics for this well-known problem, namely, a truncated branch-and-cut method, a Lagrangian heuristic, a truncated column generation method, a large neighborhood search heuristic using truncated column generation for neighborhood evaluation, and a tabu search heuristic. The first three methods are adaptations of existing methods, while the last two are new in the context of this problem. Computational results on randomly generated instances show that the column generation heuristic performs the best when enough computational time is available and stability is required, while the large neighborhood search method is the best alternative when looking for good quality solutions in relatively fast computational times.     

Determination of key parameters responsible for polymeric liner collapse in hyperbaric type IV hydrogen storage vessels

Depressurization tests at a laboratory scale, coupled with numerical modelling, are used to determine the key parameters responsible for the polymeric liner collapse in hyperbaric type IV hydrogen storage vessels. X-ray tomography allows to determine the damages suffered by the sample during the depressurization step. Results show that the differential pressure induced during the depressurization step between the liner/composite interface and the free surface of the liner is the main factor responsible for the collapse of the liner. For a given temperature, this pressure gradient can be modified by changing the maximum H₂ pressure, the emptying rate or by adding a residual pressure plateau. Temperature is also of prime importance by influencing the yield point of the liner, the interface resistance and the amount of gas dissolved into the vessel. Thus, increasing temperature also increases the risk of liner collapse for the same gas exposure conditions.     

The crystal chemistry of cerium in the monazite structure-type phase of tailored-ceramic nuclear waste forms

Monazite prepared at 1200°C in air was observed to incorporate cerium as 3+ and not 4+ even when charge compensation mechanisms for Ce⁴⁺ inclusion were present. The consequences of this phenomenon for the use of monazite structure-type solid solutions for transuranic nuclide isolation in radioactive waste management are discussed. The use of cerium as a substitute for the actinides is also considered.     

Effect of Carnobacterium piscicola on aroma formation in sausage mince

The metabolites from leucine degradation play a key role in sausage aroma. Leucine catabolism is particularly important in Carnobacterium piscicola. The purpose of the study was to determine the effect of C. piscicola inoculation on the aroma of a sausage model and on leucine catabolism. Sensory analysis and implantation of Carnobacterium were performed. Aromatic compound production from (3)H leucine added to the sausage model was measured by high-performance liquid chromatography. After 18 days of ripening, the level of Carnobacterium species was 10-fold higher in sausages inoculated with C.?piscicola than in the control sausages. Addition of C.?piscicola enhanced the development of sausage aroma. The leucine was 10% more degraded in the models inoculated with C. piscicola. 3-Methyl butanoic acid was the main metabolite detected and the highest production of α-ketoisocaproic acid and hydroxy α-ketoisocaproic acid were detected in the sausage model inoculated with C. piscicola.     

Analysis of the survival of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in food-grade lubricants

Listeria monocytogenes is a ubiquitously occurring Gram-positive bacterium, which is associated with raw ready-to-eat foods, in particular with smoked or graved salmon. Due to its tenacity and psychrotrophic growth properties, it may persist on the equipment and machinery used in food production. In this study, we analysed the survival of three L. monocytogenes strains in eight H1 lubricants, seven greases and one oil, applicable for food-processing machinery. None of the native lubricants contained Listeria spp. above the detection limit of 10³ cfu/g. In artificially contaminated lubricants, the viable counts of different L. monocytogenes strains decreased by more than 99.9% within 7 days, and the reduction rates were found to dependent on the composition of the respective lubricant as well as on the L. monocytogenes strain. Chemical binding of either benzoate or acetate to native grease 3 caused a similar anti-listerial activity, but a decreased effect was observed when stearic acid was used. When benzoate, acetate, salicylate or parabene was added at a concentration of 0.5% to native grease 1, similar anti-listerial effects were observed. The water content (0, 1 and 5%) and the age of the lubricant did not influence the results. Used lubricants originating from dismantled industrial machinery did not contain L. monocytogenes, though this microorganism was re-isolated from the lubricants following artificial contamination. Thus, there is no evidence that L. monocytogenes replicate or persist in the H1 lubricants used in this study.     

Screen-printable silver pastes with metallic nano-zinc and nano-zinc alloys for crystalline silicon photovoltaic cells

Silver metallization pastes for crystalline silicon PV cells containing nanosized metallic zinc were found to be superior to commercial pastes containing micrometer-sized metallic zinc and micrometer sized zinc oxide in terms of efficiency and firing window. Efficiency performance decreases as the size of the particles increases: nano-Zn > 3.6 μm Zn > 4.4 μm Zn. Advanced electron microscopy techniques were used to investigate the interfacial microstructure between the front-side contact and the Si emitter of nanosized zinc additive based cells fired at temperatures from below to above optimal. These microstructural observations confirmed the possibility of a tunneling mechanism of current flow (a "nano-Ag colloid assisted tunneling" model) in the absence of Ag crystallites. Contact resistance maps were used to guide sampling, leading to a better understanding of the relationship between microstructure and contact resistance. Low contact resistance and higher cell efficiency, especially at under- and overfiring temperature conditions, are due to more uniform silicon nitride etching obtained through the use of nanosized metallic zinc additives.     

Hardness of moist agglomerates in relation to interparticle friction, capillary and viscous forces

Wet agglomerates deform plastically until they break through crack propagation. On the particulate level, liquid bridges are responsible for the strength of the wet agglomerate as they hold the particles together. Recent micro-scale studies have identified the role of liquid surface tension, bridge Laplace pressure and liquid viscosity, which, in combination, explain the axial strength of pendular liquid bridges. Different situations exist depending on the degree the liquid wets the particles and on the saturation of the agglomerate mass.On the wet agglomerate level, the hardness is related to three factors: the liquid binder surface tension and viscosity and the interparticle friction. A simple model is developed in this paper, based on the powder and liquid binder properties, which shows that the forces due to interparticle friction are generally predominant in wet agglomerates made from non-spherical particles. Although mechanical interlocking is not accounted for, the model yields accurate prediction of wet agglomerate hardness independently measured on wet masses of varying composition. This theoretical hardness could prove an interesting tool for wet granulation research and technology.