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NTC thermistor ferrite composite for temperature sensing with reduced humidity influence
Get PDFNegative temperature coefficient (NTC) thermistor semiconducting oxides, such as ferrites used as resistance-based temperature sensors, remain in research focus, as they are basic building blocks of many electronic systems. In this work we have investigated NTC thermistor properties of a ferrite composite (MnFe2O4/Fe2O3) ceramics obtained by solid-state sintering in the form of a bulk sample with a diameter of 8.7 mm and thickness of 1.8 mm. We obtained a thermal (material) constant (B10,90) of 4390 K from measured impedance at 100 Hz in the temperature range 10 - 90 C and temperature sensitivity (alpha) of -4.87 %/K at 25 oC, that was within the range required for a commercial NTC thermistor material (B between 2000 and 5000, between -2 and 6% K at room temperature -25 oC). The influence of relative humidity (RH) in the range 30-90% at 25 and 50 C on impedance in the frequency range 50 Hz – 1 MHz was monitored. The obtained results showed that at 100 Hz the change in impedance was from 8.15 to 3.56 Mohm at 25 oC and 2.81 to 1.65 Mohm for RH from 30 to 90%, indicating that the humidity influence was reduced compared to other NTC thermistor materials. Future work will focus on applying this ferrite composite in flexible printed temperature sensors
A fitness landscape instability governs the morphological diversity of tip-growing cells
Get PDFCellular morphology affects many aspects of cellular and organismal physiology. This makes it challenging to
dissect the evolutionary basis for specific morphologies since various cellular functions may exert competing
selective pressures on this trait, and the influence of these pressures will depend on the specific mechanisms
of morphogenesis. In this light, we combined experiment and theory to investigate the complex basis for
morphological diversity among tip-growing cells from across the tree of life. We discovered that an instability
in the widespread mechanism of ‘‘inflationary’’ tip growth leads directly to a bifurcation in the common fitness
landscape of tip-growing cells, which imposes a strict global constraint on their morphologies. This result rationalizes the morphology of an enormous diversity of important fungal, plant, protistan, and bacterial systems. More broadly, our study elucidates the principle that strong evolutionary constraints on complex traits,
like biological form, may emerge from emergent instabilities within developmental systems
Analysis of allometry and condition factor of the white bream (Blicca bjoerkna) in the Danube river near Belgrade (1168-1170 rkm)
Get PDFThis study was conducted on individuals of White bream from commercial catches carried out between December 2014 and May 2015 at two locations in the Danube near Belgrade, Veliko ratno ostrvo (VRO) – the main canal of the Danube, with fast water flow and Jojkića Dunavac (JD) – an armlet of the Danube, with slow water flow. A total of 377 individuals were analysed. Total body length (L, cm) and body weight (W, g) of each sampled individual were measured, and Fulton's condition factor was calculated. Average TL of the fish individuals from the VRO and JD were 23.8±2.4 and 23.1±1.7, respectively, and average W were 201.0±73.0 and 164.4±42.2, respectively. In general, fish from location VRO were in better condition (K = 1.44±0.16) compared to sample
from JD (K = 1.31±0.11). Individuals in the sample from VRO had a positive allometric growth (a = -2.22, b =
3.28, r² = 0.89), while those from JD had a negative allometric growth (a = -1.79, b = 2.93, r² = 0.85). Based on
the results of this study, positive allometric growth (b > 3) and fish condition indicated that individuals from VRO
increased body mass more than body length. The source of food, its availability, and better habitat conditions at
VRO could be the reason for the differences in the growth and condition of the fish from the investigated locations.
The presented results can be applied in fisheries management plans and sustainable exploitation of this fish species
as it provides information on stock condition
ALBANIAN ROACH Pachychilon pictum (Heckel & Kner, 1858)
No full textŠARADAN, BRCAK, MORANEC Pachychilon pictum (Heckel & Kner, 1858)Telo šaradana je izduženo (Slika 145). Usne su debele, a donja
usna je sastavljena iz tri režnja, pri čemu je srednji režanj dugačak i
dobro razvijen. Prednji deo gornje usne pokriva mesnata rostralna
kapica, razvijenija kod odraslih. Leđa su plavo-siva do crna, bokovi
su svetliji, a trbuh beo. Po telu postoje karakteristične tamnosmeđe
šare različitog oblika i veličine koje nastaju zbog tamnije pigmentacije
pojedinačnih krljušti ili grupa krljušti. Kod juvenilnih jedinki
postoji i tamna pruga koja se gubi sa starošću. Prva negranata žbica
leđnog peraja upadljivo je kraća od ostalih žbica. Peraja: D III + 7–9;
A III + 8–10; P I + 11–16; V II + 7–8. Broj krljušti u bočnoj liniji
iznosi 40–49, a broj kičmenih pršljenova 34–38. Broj branhiospina
je 9–14. Ždrelni zubi su jednoredni, DF 5(4)–(5)6 (Šorić, 1983).
Naraste do 20 cm i dostigne masu tela do 70 g (Kottelat & Freyhof,
2007).
The body of the Albanian roach is elongated (Figure 145). The
lips are thick and the lower lip consists of three lobes with a long and
well-developed median lobe. The anterior part of the upper lip is covered
by the fleshy, overhanging rostral cap, which is more developed
in adults. The back is blue-grey to black, the flanks are lighter and the
belly is white. There are characteristic dark brown marks of various
shapes and sizes on the body, caused by darker pigmentation of individual
scales or groups of scales. Juveniles also have a dark stripe that
disappears with age. The first spine of the dorsal fin is noticeably shorter
than the other spines. Fins: D III + 7–9; A III + 8–10; P I + 11–16; V II
+ 7–8. The number of scales in the lateral line is 40–49 and the number
of vertebrae is 34–38. The number of gill rakers is 9–14. The pharyngeal
teeth are in a single row, DF 5(4)–(5)6 (Šorić, 1983). It grows up to 20
cm and reaches a body mass of up to 70 g (Kottelat & Freyhof, 2007)
An innovative in-situ AFM system for a soft X-ray spectromicroscopy synchrotron beamline
Get PDFMultimodal imaging and spectroscopy like concurrent Scanning
Transmission X-ray Microscopy (STXM) and X-ray Fluorescence
(XRF) are highly desirable as they allow retrieving complementary
information. This paper reports on the design, development,
integration and field testing of a novel in-situ Atomic Force
Microscopy (AFM) instrument for operation in high vacuum in a
synchrotron soft X-ray microscopy STXM-XRF end-station. A
combination of XRF-AFM is demonstrated for the first time in the
soft X-ray regime, with an outlook for the full XRF-STXM-AFM combination
ZnO and Fe2TiO5 Nanoparticles Obtained by Green Synthesis as Active Components of Alginate Food Packaging Films
Get PDFIn this paper, we have systematically studied the structural, morphological, and optical properties of Ni-doped TiO2, synthesized via a simple, cost-effective electrospinning method followed by calcination at 500 C. The nanofibers with a core-shell structure were relatively homogeneous, smooth and randomly oriented, and there were no significant differences in fiber diameters due to Ni2+ content. Core loss mapping using electron energy loss spectroscopy confirmed an even distribution of titanium and relatively uniform nickel in the fibers. It was found that doping with 0.5 mol.% Ni2+ decreased the rutile content, while doping with 1 mol.% Ni2+ resulted in a pure anatase phase with a significantly increased specific surface area (36.6 m2/g). Further increase in Ni2+ content (3-10 mol.%) not only prolonged the response of TiO2 nanofibers to visible light, but also increased the specific surface area (49.5 m2/g), decreased crystallite size (7 nm), and increased rutile content in TiO2 (33 wt.%). Photoluminescence analysis revealed that doping TiO2 with different amounts of Ni2+ leads to a gradual decrease of emission spectra intensity and red shift in the maxima positions. The XPS results confirmed that as the Ni2+ content enlarged, the Ti2+ and Ti3+ content increased significantly, effectively promoting the formation of oxygen vacancies. Raman analysis showed that an increase in nickel content (3-5 mol.%) led to a decrease and shift in peak intensity due to Ti3+ formation and also the possible presence of NiTiO3 phases. HRTEM analysis showed that Ni was doped into the substitution sites of both the anatase and rutile TiO2 lattice but had a stronger influence on the distortion of the anatase phase. The obtained results indicate that Ni-doped TiO2 nanofibers are good candidates for photocatalytic applications
DEGRADATION OF TETRACYCLINE ANTIBIOTICS IN AQUATIC ENVIRONMENT BY UV IRRADIATION AND FERRIC ION PHOTOLYSIS
No full textTetracyclines are largely used antibiotics in human and veterinary medicine due to their wide
spectrum of antibacterial activity. Besides the benefits of their use in defense from pathogenic
microorganisms their presence in surface water, groundwater, wastewater treatment plant, effluent
and influents, and sludge is a growing problem for the environment. Understanding of interactions
between tetracyclines and metal ions in aqueous ecosystems are of special importance for
development of methods for their removal, especially advanced oxidation processes initiated or
enhanced by UV irradiation. The influence of pH and the presence of ferric ions on photosensitivity of
tetracycline antibiotics tetracycline and doxycycline to UV A and UV B irradiation were investigated
by UV–Vis, Raman and EPR spectroscopy, MS, HPLC, and cyclic voltammetry. The formation of
Fe3+-tetracycline complexes is pH dependent. UV-Vis and Raman spectra showed Fe3+ binding with
both tetracycline antibiotics through amide and OH groups in tricarbonylamide moiety of A ring and
phenolic diketone oxygen atoms of BCD system at acidic solutions pH≤5. MS showed 1:1
stoichiometry of Fe3+-tetracycline antibiotic complexes. Coordination interactions between Fe3+ and
tetracyclines are reversible. Tetracyclines are released unchanged from their Fe3+ complexes by pH
increase. The effect of UV irradiation on tetracyclines, their Fe3+ complexes and tetracyclines in the
presence of Fe3+ prior the formation of the complexes was investigated at pH 5. The results showed
that coordination of tetracyclines with Fe3+ makes them less susceptible to oxidation with hydroxyl
radical generated by UV-induced photolysis of Fe3+–OH- complexes. The exposure of tetracyclines to
UV-A and UV-B irradiation led to their photodegradation at neutral and basic pH, while acidic pH
preserved tetracyclines from photodegradation. Redox properties of tetracyclines are pH dependent
and related to deprotonation of phenolic diketone moiety of BCD system which makes them more
susceptibile to oxidation at higher pH
Raman microspectroscopy of “tensile flexure wood” in Populus x euramericana
No full textWoody plants in response to gravitropic or phototropic environmental stimuli develop a reaction
wood to overcome stem lean. Reaction wood in Angiosperms is called tension wood (TW). TW
contains more cellulose and less lignin. TW fibers, gelatinous fibers (G-fibers), differ anatomically from
normal wood (NW) fibers formed in the absence of stimuli. Typical G-fibers are characterized by an
inner gelatinous (G) cell wall (CW) layer. On the other hand, in response to mechanical stress, such
as strong wind or artificial bending treatments, woody plants develop “flexure wood”. “Flexure wood”
formed under tension in Angiosperms is termed “tensile flexure wood” (TFW). In comparison with
TW, TFW fibers are characterized by a thinner G-layer but also a thinner S-layer. TFW, similarly to TW,
represents an increased source of non-recalcitrant cellulose for biofuel production. The efficiency
of bioethanol production depends on lignocellulose composition. It increases with higher cellulose
content, lower cellulose crystallinity (hemicellulose/cellulose ratio), lower lignin content, higher
coniferaldehyde content, higher syringyl (S) to guaiacyl (G) ratio, and lower ash content. We performed
histochemical, SEM, and Raman microspectroscopic analysis of NW and TFW on the cross sections
of juvenile Populus x euramericana trees formed as a response to severe long-term static bending.
Histochemical analysis shows the difference in lignin distribution in different CW layers of NW and
TFW fibers and the presence of phenolic or lignin-like substances in the G-layer. SEM micrographs
present the differences in CW shape, thickness, and ultrastructure between NW and TFW fibers.
Raman microspectroscopy provides a spatial distribution of CW components in NW and TFW fibers.
The difference in the structure of cellulose, hemicellulose and pectin, but also lignin, is suggested
in CWs of TFW compared to NW, based on the shifts of the bands at 1100 cm-1, 835 and 655 cm-1
characteristic for cellulose, hemicellulose and pectin, the band at 1587 cm-1 assigned to lignin, and
the band at 1687 cm-1 assigned to coniferyl alcohol and coniferaldehyde. In addition, the higher S/G
ratio in TFW compared to NW is suggested. Presented preliminary data encourage further work on P.
euramericana TFW examination for biofuel production. Planting P. euramericana windbreak forests
could provide TFW as an increased source of non-recalcitrant cellulose for biofuel production
Aliens Among Us: Sensitivity of the Invasive Alien Fish Black Bullhead Ameiurus melas as a Bioindicator of Pollution and Its Safety for Human Consumption
No full textThis study aims to evaluate the black bullhead Ameiurus melas, an invasive alien fish (IAF)
in Serbia, as a bioindicator organism and assess the safety of natural and aquaculture specimens for human consumption. A set of biomarkers was analysed to assess the bioindicator potential at a site exposed to agricultural activities. The genotoxic response was determined by an alkaline comet assay and micronucleus assay in fish erythrocytes, and the metal pollution index (MPI) was calculated to assess the toxic element burden on fish. Water quality was evaluated using physicochemical parameters and faecal indicator bacteria, while sediment was analysed for the presence of pesticides. The concentration of metals and metalloids in fish muscle was monitored to assess the safety for human consumption, and the corresponding indices (MAC, THQ, HI) were calculated. All biomarker responses were linked by the integrated biomarker response (IBR). Water analyses indicated the absence of communal wastewater, while sediment analysis revealed the presence of paclobutrazol, bifenthrin, and cyfluthrin. The IBR showed that June and September had the highest stress indices, coinciding with peak pesticide use and precipitation. All indices confirmed the safety of black bullhead for human consumption. This study highlighted the uses of nature-based solutions to the problem of IAF
WOUND HEALING POTENTIAL OF BLACK RASPBERRY SEED OIL
No full textThe skin is subject to various influences from the external environment that lead to minor or serious
problems and diseases. Among the most prevalent is trauma, an injury characterized by disrupting
the normal anatomical structure and function of the skin caused by a cut, a blow or a burn, which
consequently makes the body become more susceptible to infection. On the basis of numerous
animal experiments and human studies, plant oils are recognized to play an important role in
regenerative processes, whether they are used as an integral part of the diet or an active ingredient
in pharmaceutical preparation intended for local application. This study aimed to investigate the
wound-healing potential of black raspberry (Rubus occidentalis L., Rosaceae) seed oil, as well as its
chemical characterization and antimicrobial activity against the most common skin pathogens. GCMS analysis was performed to identify the chemical composition of fatty acids in the black
raspberry seed oil and revealed that polyunsaturated fatty acids (PUFA) dominated – the most
abundant were linoleic (C18:2n-6; 39.30%) and α-linolenic (C18:3n-3; 30.49%) acids, followed by
monounsaturated oleic acid (C18:1n-9; 18.94%). The amount of saturated fatty acids (SFA) was
notably lower, including palmitic (C16:0; 2.91%), arachidic (C20:0; 1.37%) and behenic (C22:0;
1.01%) acids as the main representatives. The black raspberry seed oil demonstrated significant
antimicrobial activity against the bacterial strains Salmonella Typhimurium, Escherichia coli and
Bacillus cereus, in addition to antifungal activity against micromycetes Aspergillus fumigatus, A.
niger, A. versicolor and Trichoderma viride. After examination of the relative growth rate (%) of
HaCaT cells treated with different concentrations of black raspberry seed oil (20–400 µg/mL), by
cell viability assay, no cytotoxicity was found (IC50 > 401 µg/mL). The wound healing activity, in
terms of migratory ability, was evaluated by scratch assay in the same cell line, whereby cell
migration into the wounded area was monitored using an Inverted Microscope. The closure of the
gap distance (wound closure) was found to be approximately 2-fold higher in cells treated with 200
µg/mL of black raspberry seed oil (41.77%) than in non-treated cells (17.34%). The results showed
that black raspberry seed oil is a rich source of PUFA, with promising potential in the treatment of
skin wounds associated with infections