52 research outputs found
Determination of essential and toxic elements in products of milling wheat
The bread wheat bran is used as a raw material rich in dietary fiber in the production. Therefore, it is necessary to monitor the content of essential and toxic elements in the flour and bran. This paper investigates essential (Zn, Cu, Fe and Mn) and toxic (Pb, Cd, Hg and As) elements in products of milling wheat grown in the whole territory of Banat, the region in Serbia. Inductively coupled plasma mass spectrometry was used for analysis. The mean contents of the following elements Pb, Cd, Hg, As, Fe, Mn and Zn in wheat kernels were 0.143, 0.007, 0.017, 35.7643, 50.865 and 21.174 mg/kg, respectively. Cluster analysis (CA) and principal component analysis (PCA) was applied to discriminate and to group the different samples, according to element content. Quality results show that the first two principal components, accounting for 80.17% of the total variance, can be considered sufficient for data representation and the first two principal components of toxic elements and essential microelements. Cd (15.28%), Zn (17.91%), Cu (17.08), Fe (16.91%) and Mn (17.54%), have been found the most influential for the first factor coordinate calculation, while the contribution of Pb (27.93%) and Hg (61.86%) has been the most important variable for the second factor coordinate calculation
Determination of essential and toxic elements in products of milling wheat
The bread wheat bran is used as a raw material rich in dietary fiber in the production. Therefore, it is necessary to monitor the content of essential and toxic elements in the flour and bran. This paper investigates essential (Zn, Cu, Fe and Mn) and toxic (Pb, Cd, Hg and As) elements in products of milling wheat grown in the whole territory of Banat, the region in Serbia. Inductively coupled plasma mass spectrometry was used for analysis. The mean contents of the following elements Pb, Cd, Hg, As, Fe, Mn and Zn in wheat kernels were 0.143, 0.007, 0.017, 35.7643, 50.865 and 21.174 mg/kg, respectively. Cluster analysis (CA) and principal component analysis (PCA) was applied to discriminate and to group the different samples, according to element content. Quality results show that the first two principal components, accounting for 80.17% of the total variance, can be considered sufficient for data representation and the first two principal components of toxic elements and essential microelements. Cd (15.28%), Zn (17.91%), Cu (17.08), Fe (16.91%) and Mn (17.54%), have been found the most influential for the first factor coordinate calculation, while the contribution of Pb (27.93%) and Hg (61.86%) has been the most important variable for the second factor coordinate calculation
Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system
Mixtures of MgO-TiO2 were mechanically activated using high-energy planetary ball mill during 5, 10, 20, 40, 80 and 120 minutes. Sintering process was preformed in air at 1100Ā°-1400Ā°C for 2h. The decrease in powder's particle size was noticed as the time of mechanical activation increased and confirmed by particle size analyzer. XRD analyses were performed in order to acquire the information about phase composition. Different ratio mixtures of MgTiO3 and Mg2TiO4 are present within all sintered samples. The effect of tribophysical activation on microstructure was investigated by scanning electron microscopy. The differential thermal gravimetric analysis has been performed in order to investigate thermal behaviour of the mixtures.SmeÅ”e MgO-TiO2 su mehaniÄki aktivirane u visoko-energetskom planetarnom mlinu tokom 5, 10, 20, 40, 80 i 120 minuta. Fazni sastav je odreÄen rendgenskom difrakcijom. Sa porastom vremena mlevenja, primeÄeno je smanjenje veliÄine Äestica praha. TakoÄe, ispitan je i efekat tribofiziÄke aktivacije na mikrostrukturu praha metodom skenirajuÄe elektronske mikroskopije. Radi ispitivanja termiÄkih svojstava praha, uraÄena je diferencijalna termijska analiza. Proces sinterovanja izveden je u vazduhu u temperaturnom opsegu od 1100Ā°-1400Ā°C tokom 2 sata. U svim sinterovanim uzorcima uoÄeno je prisustvo dve faze MgTiO3 i Mg2TiO4 ali njihov meÄusobni odnos koncentracija varira u odnosu na temperaturu sinterovanja
Genotype and soil type influence on morphological characteristics, Yield and oil content of oil-flax
The three-year trial investigated the individual and the mutual interaction among three genotypes of oil-flax (Olin, Zlatko, Ljupko) and subtype of soil (chernozem with signs of gleyzation and chernozem on sandy loess) and their influence on morpho-physiological traits, yield and oil-flax oil content. The tallest stems (70.3 cm) had the Olin variety in agro-ecological conditions of Southern Banat region. Number of capsules per plant and number of grains per capsule was dependent on agroecological conditions in the investigated year. The largest number of capsules (68) per plant had the Zlatko variety, while the highest average grains number in the capsules (8.2) was at the Olin variety. The obtained values of the studied varieties for these two variables were not statistically significant. On average, the highest oil-flax seed yield gave the Ruben variety (1416.3 kg ha-1), which was higher for about 9.45% compared to the Ljupko variety, and 9.65% compared to the Olin variety. The highest oil content was at the Ljupko variety (41.1%). This value was higher by 1.21 rel.% compared to the Zlatko variety (40.6%), and 0.07 rel.% compared to the Olin variety (40.8%). Three-year average grains yield (Starcevo locality) was 1430.6 kg ha-1. The yield increasing at chernozem with signs of gleyzation compared to plants grown on chernozem on sandy loess (Devojacki Bunar locality) was 17%. On the other hand, the oil content in general was higher in this type of soil than on chernozem with signs of gleyzation (41.0% vs. 40.7%)
Promene ekscitabilnosti motorne kore udružene sa zamorom miÅ”iÄa kod obolelih od Parkinsonove bolesti
Background/Aim. Transcranial magnetic stimulation (TMS) is a standard technique for noninvasive assessment of changes in central nervous system excitability. The aim of this study was to examine changes in responses to TMS in patients suffering from Parkinson's disease (PD) during sustained submaximal isometric voluntary contraction [60% of maximal voluntary contraction (MVC)] of the adductor pollicis muscle, as well as during a subsequent recovery period. Methods. Cortical excitability was tested by single TMS pulses of twice of the motor threshold intensity applied over the vertex. Testing was carried out during the sustained contraction phase every 10 s before and every 5 s after the endurance point, as well as at rest and during brief 60% MVC contractions before (control), immediately after the sustained contraction, and at 5 min intervals during the recovery period. Results. Although the PD patients could sustain the contraction at the required level for as long period of time as the healthy subjects (though contraction level subsided more rapidly after the endurance point), effects of muscle fatigue on the responses to TMS were different. In contrast to the findings observed in the healthy people where motor evoked potentials (MEP) and EMG silent period (SP) in fatigued muscle gradually diminished during contraction up to the endurance point, and increased thereafter, in the majority of patients no changes occurred in MEP size (peak and area) of the adductor pollicis muscle, either before or after the endurance point. On the other hand, changes in the SP of this muscle differed among the subjects, showing a gradual increase, a decrease or no changes in duration. The trends of changes in both MEP size and SP duration in the musculus brachioradialis varied among the tested PD patients, without any consistent pattern, which was in contrast with the findings in the healthy people where both measures showed a gradual increase from the beginning of the sustained contraction. A complete dissociation between changes in MEP and SP during fatigue was also of note, which differed sharply from the findings in the healthy people in who fatigue induced changes in these measures followed identical patterns. Conclusion. These results in the PD patients suggest the presence of impairment and/or compensatory changes in mechanisms responsible for adaptation of voluntary drive as well as for matching between cortical excitation and inhibition which become manifest in demanding motor tasks such as those imposed by muscle fatigue.Uvod/Cilj. Transkranijalna magnetna stimulacija (TMS) je standardna tehnika za neinvazivnu procenu promena ekscitabilnosti centralnog nervnog sistema. Cilj rada je bio da se prikažu promene odgovora na TMS kod obolelih od Parkinsonove bolesti (PB) za vreme trajanja submaksimalne voljne izometrijske kontrakcije [60% maksimalne voljne kontrakcije (MVK)] miÅ”iÄa adductor pollicis, kao i tokom perioda oporavka. Metode. Kortikalna ekscitabilnost testirana je TMS pulsevima dvostruko veÄeg intenziteta od motornog praga. Testiranje je vrÅ”eno za vreme održavanja kontrakcije na svakih 10 s do taÄke izdržljivosti i na svakih 5 s posle toga, a, takoÄe, u miru kao i za vreme kratkotrajnih 60% MVK u periodu pre (kontrola), neposredno posle održavanja kontrakcije, i u intervalima od pet minuta za vreme perioda oporavka. Rezultati. Iako su bolesnici sa PB mogli da održavaju zahtevani nivo kontrakcije jednako dugo kao i zdravi ispitanici (mada je nivo opadao brže nakon taÄke izdržljivosti), efekti miÅ”iÄnog zamora na odgovor izazvan TMS-om bili su razliÄiti. Za razliku od zdravih ispitanika kod kojih se motorni evocirani potencijali (MEP) i trajanje perioda EMG tiÅ”ine (PT) u zamaranom miÅ”iÄu postepeno smanjuju tokom kontrakcije do taÄke izdržljivosti, a zatim rastu, kod veÄine bolesnika nije doÅ”lo do promena veliÄine (maksimalna amplituda i povrÅ”ina) MEP miÅ”iÄa adductor pollicis, bilo pre ili posle taÄke izdržljivosti. S druge strane, promene PT ovog miÅ”iÄa su se razlikovale meÄu ispitanicima, pokazujuÄi bilo postepeno poveÄanje, smanjenje ili odsustvo promena. Promene kako amplitude MEP tako i trajanje PT u EMG miÅ”iÄa brahioradialisa varirale su meÄu bolesnicima sa PB, bez nekog dominantnog obrasca, po Äemu su se, takoÄe, razlikovale od promena naÄenih kod zdravih ispitanika, kod kojih su se oba parametra postepeno poveÄavala od poÄetka održavanja toniÄne kontrakcije. Upadljiva je, takoÄe, i potpuna disocijacija izmeÄu promena MEP i PT tokom zamora, Å”to je u oÅ”troj suprotnosti sa nalazom kod zdravih ispitanika gde su promene ovih parametara pratile identiÄan obrazac. ZakljuÄak. Rezultati kod bolesnika sa PB ukazuju na postojanje oÅ”teÄenja i/ili kompenzatornih promena mehanizmima odgovornih za adaptaciju voljne pobude i usklaÄivanja kortikalne eksitacije i inhibicije, koji se manifestuju tokom miÅ”iÄnog zamora i u drugim zahtevnim motornim zadacima
Maintenance of soil fertility on organic farm by modeling of crop rotation with participation alfalfa
The aim of this paper is to maintain soil fertility on an organic farm without livestock production by using alfalfa green biomass. The research was carried out on the farm of Mokrin PP company, by modeling and sizing of
crop rotation with alfalfa (Medicago sativa L.) on the non-carbonate humoglay. To ensure a cost-effective technical solution, alfalfa seed production was organized. In the autumn of 2015 alfalfa sowing was carried out in a field of 5 ha. Green biomass of the first and third cuttings, as well as crop residue after harvesting of seeds in the second cutting, were
mowed and chopped by harvester for low silage and stored in the silage-pit. After nine months, a mature alfalfa compost was obtained with optimum values
of total nitrogen (5.04%), organic matter (42.56%), C/N, pH, humidity, and EC. Two-year alfalfa utilization is the recommended time in this research because to the following benefits: in crop rotation, alfalfa field is
provided with nitrogen by symbiotic niĀtrogen fixation and the alfalfa is cultivated every five years in the same field, while in the middle of that period the field is fertilized with compost produced on the farm. The amount of compost obtained by crop rotation (2016 - 48.80 t; 2017 - 62.30 t) is enough for about 20% of the arable area per year. Thus, the fields are fertilized every fourth year with 10 t ha-1 of compost. Thanks to alfalfa biomass and seed and also nitrogen fixation, maintaining soil fertility is
resolved in a sustainable and natural way
Mass transfer and microbiological profile of pork meat dehydrated in two different osmotic solutions
The effects of osmotic dehydration on mass transfer properties and microbiological profile were investigated in order to determine the usefulness of this technique as pre-treatment for further treatment of meat. Process was studied in two solutions (sugar beet molasses, and aqueous solution of sodium chloride and sucrose), at two temperatures (4 and 22Ā°C) at atmospheric pressure. The most significant parameters of mass transfer were determined after 300 minutes of the dehydration. The water activity (aw) values of the processed meat were determined, as well as the change of the microbiological profile between the fresh and dehydrated meat. At the temperature of 22Ā°C the sugar beet molasses proved to be most suitable as an osmotic solution, despite the greater viscosity
CaO&CaSO4 and CaO&Al2(SO4)3 as Pectin PrecipitantsāModel of Overlapping Diffuse Layers
This work is concerned with the theoretical basis of novel sugar beet juice purification method using binary systems CaO&CaSO4 and CaO&Al2(SO4)3. The GouyāChapmanāStern (GCS) model of overlapping of diffuse layers of EDLs on pectin surface and that on Ca2+ and Al3+ ions, theoretically explains this method. The change of the zeta potential was used to quantitatively indicate overlapping of diffuse layers. For the experiment two model solutions of pectin (0.1 % w/w) were prepared, while the concentrations of CaO&CaSO4 and CaO&Al2(SO4)3 in the range of 50ā500 g dm-3 were used. The greater decrease in the absolute value of zeta potential indicated greater overlapping of diffuse layers between pectin particles and Ca2+ and Al3+ ions and faster coagulation of pectin. The overlapping degree increased with increased concentration of these binary systems. Pectin with a greater surface charge and multivalent Al3+ from CaO&Al2(SO4), exerted a greater impact on the zeta potential. Optimal quantities of the applied binary mixtures were as follows: 256ā640 mg g-1 pectin. This is much lower than CaO commonly used in the conventional process of sugar beet juice purification (about 9 g g-1 pectin)
Antioxidant Capacity of Nettle Leaves During Osmotic Treatment
Osmotic treatment (OT) of nettle leaves was assessed in various osmotic solutions (sugar beet molasses ā SBM and ternary aqueous solution ā TAS), at temperatures of 20, 35 and 50 Ā°C, under the atmospheric pressure. The influence of the kind of utilized osmotic solution, process temperature and osmotic time on the antioxidant activity (AOC), expressed with the spectrophotometric assays (ABTS, FRAP and DPPH), as well as two direct current polarographic assays, Hydroxo Perhydroxo Mercury (II) complex assay, based on the decrease of anodic current and assay based on the decrease of a cathodic current of Hg (II) reduction. For determination of the total phenolic content Folin-Ciocalteu assay was used. The Relative Antioxidant Capacity Index (RACI), obtained by setting equal weight for every involved assay was applied in order to get an extensive comparison among analyzed samples and between the used assays. Based on these results, after the OT of nettle leaves in TAS, the AOC decreased, while the OT in SBM increased AOC values. The phenolic antioxidant coefficients (PAC), calculated as the ratio between particular AO capacity and TPC, were used to achieve a more comprehensive comparison between analysed samples, as well as applied assays. The results of RACI evaluation revealed that the most favorable osmotic treatment is the one performed for 5h at 35 Ā°C
Study of Nanosized Hydroxyapatite Material Annealing at Different Retention Times
The aim of the study was to investigate the influence of low heating temperatures with two different retention times to optimize the process for obtaining nanosized hydroxyapatite material that can possibly be used in the fields of biology and pharmacy. Nanosized hydroxyapatite was successfully obtained by wet chemical precipitation. The annealing of the material performed at 300 oC with two different retention times i.e. 3 and 6 hours in air atmosphere. Low annealing temperature with extended retention time was selected in terms to reduce energy consumption. FTIR spectroscopy was used to confirm characteristic vibrational bands of hydroxyapatite samples, and presence of carbonate bands of hydroxyapatite annealed for 3h and 6h. X-Ray powder diffraction analysis were used to examine phase composition, determine the size of unit cells and crystallite sizes, and SEMEDS methods were used to obtain particle size and arrangement also grain growth morphology and confirmed the presence of calcium, phosphorous oxygen and carbonate peaks. The results show that different retention time has influence on particle growth as well as unit cell parameters and crystallite sizes changes of hydroxyapatite material
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