Preconcentration of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) with ethylenediamine-modified graphene oxide

We describe a novel solid phase sorbent that was synthesized by coupling graphene oxide (GO) to ethylenediamine (EDA). This nanomaterial (referred to as GO-EDA) is capable of adsorbing the ions of iron, cobalt, nickel, copper, zinc and lead. The ethylenediamine-modified graphene oxide was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. The analytical procedure relies on (a) sorption of metal ions on GO-EDA dispersed in aqueous samples; (b) filtering, and (c) direct submission of the filter paper to energy-dispersive X-ray fluorescence spectrometry. This kind of dispersive micro-solid phase extraction was optimized with respect to pH values, concentration of GO-EDA, contact time, and the effects of interfering ions and humic acid on recovery of determined elements. Under optimized conditions, the recoveries of spiked samples range from 90 to 98 %. The detection limits are 0.07, 0.10, 0.07, 0.08, 0.06 and 0.10 ng mL−1 for Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II), respectively. The method has a relative standard deviation of <6 %, and its accuracy was verified by analysis of two standard reference materials [LGC6016 (estuarine water) and BCR-610 (groundwater)]. It was successfully applied to the determination of trace amounts of these metal ions in water samples

Jakość życia osób po urazie rdzenia kręgowego

Introduction. Each year approximately 250–500 people experience spinal cord injury, most often as a result of a fall from a height or a road accident. The injured are mostly young men. The quality of life is an increasingly popular topic, which in terms of medicine is conditioned by the state of health. Research on the quality of life of people with spinal cord injury provides valuable information on the needs of people with disabilities.Aim. The aim of the study was to determine the quality of life of people after spinal cord injury.Material and Methods. The study was conducted among 30 adults after spinal cord injury from various areas of Poland. The examined group of disabled persons consisted of women and men of various ages and with each level of spinal cord injury. A survey was also conducted among 53 people who were physically fit, matched in terms of gender, age and education. The research tool applied for both groups was the WHOQOL-BREF questionnaire (The World Health Organization, a shortened version of the quality of life survey), distinguishing four areas of the quality of life: somatic, psychological, social and environmental. The analysis of the results was based on: arithmetic mean, standard deviation, distribution normality study with the Shapiro–Wilk test. In order to compare particular variables, Pearson’s linear correlation coefficient was calculated. The Mann–Whitney U test was used to assess the significance of differences between the independent groups.Results. The arithmetic mean of the quality of life result in patients after spinal cord injury was 3.83±0.79, and in the control group 4.00±0.65. The average health assessment in both groups was also slightly different: in patients with spinal cord injury it was 3.4±1.1, and in those with mobility problems respectively 3.7±0.9. The average score obtained by people with spinal cord injury in the somatic field was lower than in those who were physically fit. Also, respondents with spinal cord injuries are less satisfied with the means of transport, health care centres or living conditions, compared to those in the control group.Conclusions. Summing up the results of the study, it can be said that people with spinal cord injury have a slightly lower overall subjective quality of life than those who are physically fit. Worse quality of life of people after spinal cord injury occurs particularly in the somatic and environmental fields. (JNNN 2018;7(2):64–69)Wstęp. Każdego roku na świecie urazu rdzenia kręgowego doświadcza 250–500 tys. osób, najczęściej w wyniku upadku z wysokości lub wypadku drogowego. Poszkodowanymi są przeważnie młodzi mężczyźni. Jakość życia to coraz bardziej popularny temat, który w aspekcie medycznym uwarunkowany jest stanem zdrowia. Badania jakości życia osób po urazie rdzenia kręgowego dostarczają cennych informacji na temat potrzeb osób niepełnosprawnych.Cel. Celem badań było określenie jakości życia osób po urazie rdzenia kręgowego.Materiał i metody. Badania przeprowadzono wśród 30 osób pełnoletnich po urazie rdzenia kręgowego z różnych obszarów Polski. Badana grupa osób niepełnosprawnych składała się z kobiet i mężczyzn w różnym wieku i z każdym poziomem uszkodzenia rdzenia kręgowego. Przeprowadzono również sondaż wśród grupy kontrolnej, 53 osób sprawnych ruchowo, dobranych pod względem płci, wieku i wykształcenia. Narzędzie badawcze dla obu grup stanowił kwestionariusz WHOQOL-BREF (ang. The World Health Organization Quality of Life, skrócona wersja ankiety oceniającej jakość życia), rozróżniająca cztery dziedziny jakości życia: somatyczną, psychologiczną, socjalną i środowiskową. Do analizy wyników stosowano: średnią arytmetyczną, odchylenie standardowe, badanie normalności rozkładu testem Shapiro–Wilka. W celu porównania poszczególnych zmiennych liczono współczynnik korelacji liniowej Pearsona. Do oceny istotności różnic między grupami niezależnymi stosowano test U Manna–Whitneya.Wyniki. Średnia arytmetyczna wyniku z jakości życia u osób po urazie rdzenia kręgowego wynosiła 3,83±0,79, a w grupie osób z grupy kontrolnej 4,00±0,65. Średnia ocena stanu zdrowia w obu grupach również różniła się nieznacznie: u osób po urazie rdzenia kręgowego wynosiła 3,4±1,1, a u osób sprawnych ruchowo 3,7±0,9. Średni wynik uzyskany przez osoby po urazie rdzenia kręgowego w dziedzinie somatycznej był niższy niż u osób sprawnych ruchowo. Także osoby z uszkodzonym rdzenia kręgowego są mniej zadowolone ze środków transportu, placówek ochrony zdrowia czy warunków bytowych, w porównaniu z osobami z grupy kontrolnej.Wnioski. Podsumowując wyniki badań można powiedzieć, że osoby po urazie rdzenia kręgowego mają nieznacznie niższą ogólną subiektywną jakość życia niż osoby sprawne ruchowo. Gorsza jakość życie osób po urazie rdzenia kręgowego występuje szczególnie w dziedzinie somatycznej i środowiskowej. (PNN 2018;7(2):64–69

Electrical and magnetic characterization of ZnCr2-x V xSe4 spinel semiconductors

Single crystals of ZnCr2Se4 spinel doped with vanadium were prepared by chemical vapour transport. The chemical compositions of three crystals have been determined by X-ray diffraction. The structure refinement using the SHELXL-93 program system determine the cation distribution in the system as ZnCr2¡xVxSe4. For x values equal to 0.03, 0.1 and 0.13 the observed symmetry was cubic, space group Fd3m. Based on the structural data, influence of the V ions on the magnetic and electrical properties has been analyzed

Hopkinson-like effect in single-crystalline CdCr 2Se 4 and Cd[Cr 1.89Ti 0.08]Se 4

The static (dc) and dynamic (ac) magnetic measurements of CdCr2Se4 and Cd[Cr1:89Ti0:08]Se4 showed their ferromagnetic properties with a Curie temperature TC 130 K and revealed on the real component of ac susceptibility curve, the peaks near TC at 200 Oe, 450 Oe and 1 kOe, characteristic for the Hopkinson ones. The meaningful reduction of saturation moment to 4.73 B/f.u. for Cd[Cr1:89Ti0:08]Se4 suggests the diamagnetic con guration of Ti ions, which dilutes the ferromagnetic sublattice of Cr ones and causes reducing of the energy losses visible on the imaginary components of ac susceptibility curve. Close for zero values of higher susceptibility harmonics above TC are pointing out to the lack of the spin uctuations in the paramagnetic state

Critical behaviour of the mean-field ferromagnet Cu1.02[Cr 1.77Ti0.24]Se4

Magnetization, M, and susceptibility, , measurements showed both strong lowering of magnetic moment in comparison with CuCr2Se4 matrix and zero- eld-cooling eld-cooling susceptibility splitting characteristic for the spin-glass behaviour. Isothermal magnetization curves, M(H), easy saturate and large values both of the Curie TC = 253 K and Curie Weiss = 283:5 K temperatures indicate the ferromagnetic order which coexists with the spin-glass state. The critical behaviour investigated around the paramagnetic ferromagnetic phase transition revealed that the values of critical exponents are close to those predicted by the mean eld model for long-range magnetic interactions

Electrical and magnetic studies of the CdxCryV zSe4 Spinels

The electrical and magnetic investigations carried out on the polycrystalline spinels with the general chemical formula CdxCryVzSe4 (where z = 0:06, 0.12, 0.24, and 0.31) revealed semiconducting and ferromagnetic properties with a Curie temperature of 127.5 K. A step-like structure of the electrical conductivity, ¾(T), was observed for the polycrystal containing 6% V ions in the octahedral sites while the remaining samples showed a typical Arrhenius behaviour of ¾(T). These effects are interpreted in terms of ferromagnetic spin clusters which finally dissolve on going towards the paramagnetic limit including non-stoichiometry