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  • Author: M. Sobiesiak x
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Preparation of nanostructured carbons for solid phase extraction

Preparation of nanostructured carbons for solid phase extraction

Nanostructured carbons have been obtained by the template method using silica gel and zeolite as structure directing agents. Carbons were characterised by nitrogen adsorption, acid-base titration, XRD and TEM, thermogravimetric analysis and IR spectroscopy. All carbons show developed and uniform porous structure with the mean size range mesopore 3.4 and 4.8 nm for silica gel derived carbons and in the micropore range 1.1 nm for zeolite derived carbon. The BET surface area of silica gel derived carbons is in the range 1230-1280 m2/g while zeolite derived carbon possesses very high BET surface area 3000 m2/g. Acid-base titration shows that carbons obtained by the template method contain a significant number of surface groups. Silica gel derived carbons possess mainly carboxylic and phenolic groups with small contribution of lactone/enol groups which totals 1.1-1.5 mmol/g. Extremely high number of surface groups (mainly phenolic) demonstrates carbon derived from zeolite - 11.3 mmol/g. The presence of phenolic groups was confirmed by IR spectroscopy. To study adsorption-desorption properties of nanostructured carbons towards phenol and chlorophenols a solid phase extraction method was used. High recoveries of chlorophenols were obtained (75-93%) at the breakthrough volumes 1200-1400 mL. The recoveries are much higher these that obtained with commercially available carbon ACC (Supelco).

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The Effects of Cryotherapy on Knee Joint Position Sense and Force Production Sense in Healthy Individuals

Abstract

The proprioceptive information received from mechanoreceptors is potentially responsible for controlling the joint position and force differentiation. However, it is unknown whether cryotherapy influences this complex mechanism. Previously reported results are not universally conclusive and sometimes even contradictory. The main objective of this study was to investigate the impact of local cryotherapy on knee joint position sense (JPS) and force production sense (FPS). The study group consisted of 55 healthy participants (age: 21 ± 2 years, body height: 171.2 ± 9 cm, body mass: 63.3 ± 12 kg, BMI: 21.5 ± 2.6). Local cooling was achieved with the use of gel-packs cooled to -2 ± 2.5°C and applied simultaneously over the knee joint and the quadriceps femoris muscle for 20 minutes. JPS and FPS were evaluated using the Biodex System 4 Pro apparatus. Repeated measures analysis of variance (ANOVA) did not show any statistically significant changes of the JPS and FPS under application of cryotherapy for all analyzed variables: the JPS’s absolute error (p = 0.976), its relative error (p = 0.295), and its variable error (p = 0.489); the FPS’s absolute error (p = 0.688), its relative error (p = 0.193), and its variable error (p = 0.123). The results indicate that local cooling does not affect proprioceptive acuity of the healthy knee joint. They also suggest that local limited cooling before physical activity at low velocity did not present health or injury risk in this particular study group.

Open access