Pasiūlytas mangano nustatymo metodas geriamajame vandenyje inversinės voltamperometrijos metodu naudojant gyvsidabrio plėvelinį elektrodą. Manganui nustatyti vandens mėginio nereikia chemiškai apdoroti. Optimalios nustatymo sąlygos: kaupimo potencialas –1,75 V, kaupimo trukmė 5–30 s, anodinis tirpinimas atliekamas naudojant kvadratinės bangos voltamperometriją. Mangano aptikimo riba kaupiant jį 30 s yra apie 0,4 μg l–1, o santykiniai standartiniai nuokrypiai darbiniame koncentracijų intervale ne didesni kaip 0,10. Realios kalcio, magnio ir geležies jonų koncentracijos geriamojo vandens mėginiuose netrukdo nustatyti manganą. Metodo palyginimas su standartiniu fotometriniu metodu parodė, kad jie yra ekvivalentiški, tačiau elektrocheminis metodas gali būti taikomas labai mažoms mangano koncentracijoms nustatyti, be to, jam netrukdo geriamajame vandenyje esantys geležies jonai. Chromo nustatymui cemente gali būti naudojamas katalitinės adsorbcinės voltamperometrijos metodas naudojant kabančio gyvsidabrio lašo elektrodą. Terpės sudėtis Cr(VI) nustatyti: 0,15 mol l-1 CH3COONa, 5 mmol l-1 dietilentriaminpentaacto rūgšties (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimalios votamperometrijos sąlygos: kaupimo potencialas –0.9 V, kaupimo trukmė 5-10 s, kvadratinės bangos voltamperometrijos režimas. Cr(VI) aptikimo riba yra apie 0,05 µg l 1, santykinis standartinis nuokrypis neviršija 3%. Iš cemento mėginių chromas išekstrahuojamas vandeniu arba azoto rūgštimi. Bendras chromo kiekis... [toliau žr. visą tekstą] / There was proposed method for the determination of manganese in drinking water by inverse voltammetry using a mercury film electrode. The determination of manganese in drinking water does not need chemical treatment of a sample. Optimal detection conditions: accumulation potential of -1.75 V, accumulation time 5-30 s, anodic dissolution is performed using square wave voltammetry. Manganese accumulation by the detection limit of 30 seconds is about 0.4 mg l-1, and the relative standard deviations of the working range of concentrations do not exceed 0.10. Actual calcium, magnesium and iron ion concentration in samples of drinking water does not influence the manganese determination. Method comparison with a standard photometric method showed that they are equivalent, but the electrochemical method can be applied in very small concentrations of the manganese, in addition, it does not influence the iron ions in the drinking water. Determination of chromium in cement can be performed by catalytic adsorption voltammetry method using a hanging mercury drop electrode. The medium composition for Cr (VI) determination: 0.15 mol L-1 CH3COONa, 5 mmol l-1 diethylenetriaminepentaacetic acid (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimal voltammetry conditions: accumulation potential of -0.9 V, accumulation time 5-10 s, square wave voltammetry mode. Cr (VI) detection limit is about 0.05 mg l-1, the relative standard deviation does not exceed 3%. Chromium was extracted from the cement samples... [to full text]

There was proposed method for the determination of manganese in drinking water by inverse voltammetry using a mercury film electrode. The determination of manganese in drinking water does not need chemical treatment of a sample. Optimal detection conditions: accumulation potential of -1.75 V, accumulation time 5-30 s, anodic dissolution is performed using square wave voltammetry. Manganese accumulation by the detection limit of 30 seconds is about 0.4 mg l-1, and the relative standard deviations of the working range of concentrations do not exceed 0.10. Actual calcium, magnesium and iron ion concentration in samples of drinking water does not influence the manganese determination. Method comparison with a standard photometric method showed that they are equivalent, but the electrochemical method can be applied in very small concentrations of the manganese, in addition, it does not influence the iron ions in the drinking water. Determination of chromium in cement can be performed by catalytic adsorption voltammetry method using a hanging mercury drop electrode. The medium composition for Cr (VI) determination: 0.15 mol L-1 CH3COONa, 5 mmol l-1 diethylenetriaminepentaacetic acid (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimal voltammetry conditions: accumulation potential of -0.9 V, accumulation time 5-10 s, square wave voltammetry mode. Cr (VI) detection limit is about 0.05 mg l-1, the relative standard deviation does not exceed 3%. Chromium was extracted from the cement samples... [to full text] / Pasiūlytas mangano nustatymo metodas geriamajame vandenyje inversinės voltamperometrijos metodu naudojant gyvsidabrio plėvelinį elektrodą. Manganui nustatyti vandens mėginio nereikia chemiškai apdoroti. Optimalios nustatymo sąlygos: kaupimo potencialas –1,75 V, kaupimo trukmė 5–30 s, anodinis tirpinimas atliekamas naudojant kvadratinės bangos voltamperometriją. Mangano aptikimo riba kaupiant jį 30 s yra apie 0,4 μg l–1, o santykiniai standartiniai nuokrypiai darbiniame koncentracijų intervale ne didesni kaip 0,10. Realios kalcio, magnio ir geležies jonų koncentracijos geriamojo vandens mėginiuose netrukdo nustatyti manganą. Metodo palyginimas su standartiniu fotometriniu metodu parodė, kad jie yra ekvivalentiški, tačiau elektrocheminis metodas gali būti taikomas labai mažoms mangano koncentracijoms nustatyti, be to, jam netrukdo geriamajame vandenyje esantys geležies jonai. Chromo nustatymui cemente gali būti naudojamas katalitinės adsorbcinės voltamperometrijos metodas naudojant kabančio gyvsidabrio lašo elektrodą. Terpės sudėtis Cr(VI) nustatyti: 0,15 mol l-1 CH3COONa, 5 mmol l-1 dietilentriaminpentaacto rūgšties (DTPA), 0.7 mol l-1 NaNO3, pH = 6. Optimalios votamperometrijos sąlygos: kaupimo potencialas –0.9 V, kaupimo trukmė 5-10 s, kvadratinės bangos voltamperometrijos režimas. Cr(VI) aptikimo riba yra apie 0,05 µg l 1, santykinis standartinis nuokrypis neviršija 3%. Iš cemento mėginių chromas išekstrahuojamas vandeniu arba azoto rūgštimi. Bendras chromo kiekis... [toliau žr. visą tekstą]

Unmyelinated low threshold C-tactile fibers moderate pleasant aspects of touch. These fibers respond optimally to stroking stimulation of the skin with slow velocities (1–10 cm/s). Low threshold mechanoreceptors are arranged around hair follicles in rodent skin. If valid also in humans, hair follicle density (HFD) may relate to the perceived pleasantness of stroking tactile stimulation. We conducted two studies that examined the relation between HFD and affective touch perception in humans. In total, 138 healthy volunteers were stroked on the forearm and rated the pleasantness and intensity. Stimulation was performed by a robotic tactile stimulator delivering C-tactile optimal (1, 3, 10 cm/s) and non-optimal (0.1, 0.3, 30 cm/s) stroking velocities. Additionally, a measure of discriminative touch was applied in study 2. HFD of the same forearm was determined using the Cyanoacrylate Skin Stripping Method (CSSM), which we validated in a pretest. Women had higher HFD than men, which was explained by body size and weight. Furthermore, women rated affective touch stimuli as more pleasant and had higher tactile acuity. Depilation did not affect touch perception. A weak relationship was found between the C-tactile specific aspects of affective touch perception and HFD, and the hypothesis of HFD relating to pleasant aspects of stroking only received weak support.

Unmyelinated low threshold C-tactile fibers moderate pleasant aspects of touch. These fibers respond optimally to stroking stimulation of the skin with slow velocities (1–10 cm/s). Low threshold mechanoreceptors are arranged around hair follicles in rodent skin. If valid also in humans, hair follicle density (HFD) may relate to the perceived pleasantness of stroking tactile stimulation. We conducted two studies that examined the relation between HFD and affective touch perception in humans. In total, 138 healthy volunteers were stroked on the forearm and rated the pleasantness and intensity. Stimulation was performed by a robotic tactile stimulator delivering C-tactile optimal (1, 3, 10 cm/s) and non-optimal (0.1, 0.3, 30 cm/s) stroking velocities. Additionally, a measure of discriminative touch was applied in study 2. HFD of the same forearm was determined using the Cyanoacrylate Skin Stripping Method (CSSM), which we validated in a pretest. Women had higher HFD than men, which was explained by body size and weight. Furthermore, women rated affective touch stimuli as more pleasant and had higher tactile acuity. Depilation did not affect touch perception. A weak relationship was found between the C-tactile specific aspects of affective touch perception and HFD, and the hypothesis of HFD relating to pleasant aspects of stroking only received weak support.