Akcijsko istraživanje predstavlja specifičan proces unaprjeđivanja odgojno-obrazovne prakse djelovanjem aktera te prakse. Da bi akcijsko istraživanje bilo učinkovito, potrebno ga je smjestiti u ...kontekstualni okvir prakse nastavnika. Iako se danas sve više nastoji primijeniti akcijsko istraživanje u školama, čini se da njegova važnost još uvijek nije u potpunosti shvaćena. U radu su prikazani aspekti provedbe i evaluacije aktivnosti usmjerenih na povećanje motivacije nastavnika – refleksivnih praktičara za profesionalni razvoj, provedenih akcijskim istraživanjem s nastavnicima razredne nastave. Istraživanje je provedeno u tri faze. Prva faza uključivala je formuliranje temeljnih polazišta istraživanja, upoznavanje potencijalnih sudionika s okvirnim planom aktivnosti kao i zajedničku konkretizaciju aktivnosti nakon opredjeljenosti nastavnika za sudjelovanje u istraživanju. U drugoj fazi istraživanja realizirane su ukupno tri aktivnosti teorijskog, praktičnog i kreativnog karaktera praćene raspravama usmjerenim na maksimiziranje učinaka procesa, a paralelno s tim tekao je i proces promatranja učinaka i došlo je do formativne evaluacije procesa. Treću fazu istraživanja obilježila je sumativna evaluacija učinaka programa koja je uključivala percepcije nastavnika o učincima provedenih aktivnosti i njihove buduće planove za uključivanje u proces stručnog usavršavanja u području akcijskog istraživanja i refleksivne prakse. Rezultati istraživanja upućuju na mogućnost povećanja motivacije nastavnika – refleksivnih praktičara za profesionalni razvoj u području akcijskog istraživanja i refleksivne prakse.
Action research is a specific process aimed at improving educational practices through active involvement by those within the educational system. For action research to be effective, it needs to be placed within the contextual framework of teacher practice. Although there is an increasing effort to apply action research in schools today, its importance still seems not to be fully understood. The paper presents aspects of implementing and evaluating activities aimed at increasing the motivation of teachers - reflective practitioners for professional development, conducted through action research with classroom teachers. The research was conducted in three phases. The first phase included formulating the basic starting points of the research, familiarising potential participants with the framework plan of activities, and the joint concretisation of the activities after the teachers' commitment to participate in the research. In the second phase of the research, three activities of theoretical, practical and creative character were realised, followed by discussions aimed at maximising the effects of the process. In parallel with this, the process of observing the effects was also carried out, and a formative evaluation of the process took place. The third phase of the research was marked by a summative evaluation of the programme's effects, including the teachers' perceptions of the impacts of the implemented activities and their future plans for inclusion in the professional development process in action research and reflective practice. The research results point to the possibility of increasing the motivation of teachers - reflective practitioners for professional development in action research and reflective practice.
Guttation, the formation of exudation water, is widespread among plants and fungi, yet the underlying mechanisms remain largely unknown. We describe the conditions for inducing guttation in ...sporangiophores of the mucoracean fungus,
Phycomyces blakesleeanus
. Cultivation on peptone-enriched potato dextrose agar elicits vigorous guttation mainly below the apical growing zone, while sporangiophores raised on a glucose-mineral medium manifest only moderate guttation. Mycelia do not guttate irrespective of the employed media. The topology of guttation droplets allows identifying the non-growing part of the sporangiophore as a guttation zone, which responds to humidity and medium composition in ways that become relevant for turgor homeostasis and thus the sensor physiology of the growing zone. Apparently, the entire sporangiophore, rather than exclusively the growing zone, participates in signal reception and integration to generate a common growth output. Exogenous auxin applied to the growing zones elicits two correlated responses: (i) formation of guttation droplets in the growing and transition zones below the sporangium and (ii) a diminution of the growth rate. In sporangiophore populations, guttation-induction by exogenous control buffer occurs at low frequencies; the bias for guttation increases with increasing auxin concentration. Synthetic auxins and the transport inhibitor NPA suppress guttation completely, but leave growth rates largely unaffected. Mutants C2
carA
and C148
carA madC
display higher sensitivities for auxin-induced guttation compared to wild type. A working model for guttation includes aquaporins and mechanosensitive ion channels that we identified in
Phycomyces
by sequence domain searches.
The growing zone (GZ) of the unicellular coenocytic sporangiophore of
Phycomyces blakesleeanus
represents the site of stimulus reception (light, gravity, gas) and stimulus response, i.e., local ...modulations of the elongation growth, which may result, in dependence of the stimulus direction, in tropic bending. Until now, evidence for a possible participation of the columella in sensory reception is absent. We confirm with light microscopy earlier studies that show that the GZ and the columella are not separated by a membrane or cell wall, but rather form a spatial continuum that allows free exchange of cytoplasm and organelle transport. Evidence is presented that the columella is responsive to external stimuli. Columellae, from which spores and sporangial cell wall had been removed, respond to exogenous auxin with a local depolarization of the membrane potential and an increased growth rate of the GZ. In contrast, auxin applied to the GZ causes a decrease of the growth rate irrespective of the presence or absence of sporangia. The response pattern is specific and relevant for the sensory reception of
Phycomyces
, because the light-insensitive mutant C148
carAmadC
, which lacks the RAS-GAP protein MADC, displays abnormal IAA sensitivity and membrane depolarization. We argue that the traditional concept of the GZ as the only stimulus-sensitive zone should be abandoned in favor of a model in which GZ and columella operate as a single entity capable to orchestrate a multitude of stimulus inputs, including auxin, to modulate the membrane potential and elongation growth of the GZ.
•Levan and pullulan coated CeO2 nanoparticles decrease toxicity to V. fischeri.•Coating increased nanoparticles’ bioaccumulation in Daphnia magna.•All coated CeO2 decrease the toxicity of uncoated ...ones at 100 mg L−1 in D. magna.•Glucose-coated CeO2 increased the CO2 production in Daphnia magna at 200 mg L−1.•Uncoated and coated CeO2 did not affect early zebrafish development and mortality.
Cerium oxide nanoparticles (nCeO2) have widespread applications, but they can be hazardous to the environment. Some reports indicate the toxic effect of nCeO2 on tested animals, but literature data are mainly contradictory. Coating of nCeO2 can improve their suspension stability and change their interaction with the environment, which can consequently decrease their toxic effects. Herein, the exopolysaccharides levan and pullulan, due to their high water solubility, biocompatibility, and ability to form film, were used to coat nCeO2. Additionally, the monosaccharide glucose was used, since it is a common material for nanoparticle coating. This is the first study investigating the impact of carbohydrate-coated nCeO2 in comparison to uncoated nCeO2 using different model organisms. The aim of this study was to test the acute toxicity of carbohydrate-coated nCeO2 on the bacterium Vibrio fischeri NRRL B-11177, the crustacean Daphnia magna, and zebrafish Danio rerio. The second aim was to investigate the effects of nCeO2 on respiration in Daphnia magna which was performed for the first time. Finally, it was important to see the relation between Ce bioaccumulation in Daphnia magna and Danio rerio and other investigated parameters. Our results revealed that the coating decreased the toxicity of nCeO2 on Vibrio fischeri. The coating of nCeO2 did not affect the nanoparticles’ accumulation/adsorption or mortality in Daphnia magna or Danio rerio. Monitoring of respiration in Daphnia magna revealed changes in CO2 production after exposure to coated nCeO2, while the crustacean's O2 consumption was not affected by any of the coated nCeO2. In summary, this study revealed that, at 200 mg L−1, uncoated and carbohydrate-coated nCeO2 are not toxic for the tested organisms, however, the CO2 production in Daphnia magna is different when they are treated with coated and uncoated nCeO2. The highest production was in glucose and levan-coated nCeO2 according to their highest suspension stability.
Daphnia magna (D. magna), Danio rerio (D. rerio), Vibrio fischeri (V. fischeri)
The roles of fungal auxins in the regulation of elongation growth, photo-, and gravitropism are completely unknown. We analyzed the effects of exogenous IAA (indole-3-acetic acid), various synthetic ...auxins including 1-NAA (1-naphthaleneacetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid), and the auxin transport inhibitor NPA (N-1-naphtylphtalamic acid) on the growth rate and bending of the unicellular sporangiophore of the zygomycete fungus,
Phycomyces blakesleeanus
. Sporangiophores that were submerged in an aqueous buffer responded to IAA with a sustained enhancement of the growth rate, while 1-NAA, 2,4-D, and NPA elicited an inhibition. In contrast, sporangiophores kept in air responded to IAA with a 20 to 40% decrease of the growth rate, while 1-NAA and NPA elicited an enhancement. The unilateral and local application of IAA in the growing zone of the sporangiophore elicited in 30 min a moderate negative tropic bending in wild type C2 and mutant C148
madC
, which was, however, partially masked by a concomitant avoidance response caused by the aqueous buffer. Auxin transport-related genes ubiquitous in plants were found in a BLAST search of the
Phycomyces
genome. They included members of the AUX1 (auxin influx carrier protein 1), PILS (PIN-LIKES, auxin transport facilitator protein), and ABCB (plant ATP-binding cassette transporter B) families while members of the PIN family were absent. Our observations imply that IAA represents an intrinsic element of the sensory transduction of
Phycomyces
and that its mode of action must very likely differ in several respects from that operating in plants.
Infective diseases have become health threat of a global proportion due to appearance and spread of microorganisms resistant to majority of therapeutics currently used for their treatment. Therefore, ...there is a constant need for development of new antimicrobial agents, as well as novel therapeutic strategies. Quinolines and quinolones, isolated from plants, animals, and microorganisms, have demonstrated numerous biological activities such as antimicrobial, insecticidal, anti-inflammatory, antiplatelet, and antitumor. For more than two centuries quinoline/quinolone moiety has been used as a scaffold for drug development and even today it represents an inexhaustible inspiration for design and development of novel semi-synthetic or synthetic agents exhibiting broad spectrum of bioactivities. The structural diversity of synthetized compounds provides high and selective activity attained through different mechanisms of action, as well as low toxicity on human cells. This review describes quinoline and quinolone derivatives with antibacterial, antifungal, anti-virulent, antiviral, and anti-parasitic activities with the focus on the last 10 years literature.
Previously, we performed population pharmacokinetic analysis and indicated age, mycophenolate mofetil (MMF)/mycophenolic acid (MPA) daily dose, and presence of nifedipine in patient therapy as ...significant predictors of MPA apparent clearance (CL/F) variability. This study aimed to determine the reliability of previously published population pharmacokinetic models derived from similar studies. Furthermore, this study investigated correspondence between chosen population models from the literature.
By means of the Monte Carlo simulation method, pharmacokinetic models from different studies are simulated and analysed in the range of standard deviations of measured system parameters as well as the range of observed model parameters taken from the comparison studies.
The 1000 numerical simulations were performed for every analysed model in order to calculate the most possible MPA CL/F values according to the expected values from the performed experiment. Fitting our results with other models showed how the presence of nifedipine makes difference in MPA CL/F values.
By testing the data from selected studies into our model, a similar range of expected CL/F values was obtained, which may confirm the validity of our model. The results of our population pharmacokinetic study are partially applicable in models by other researchers.
It was demonstrated that cetuximab-induced tumor regression is based on the effects exerted by immune cells included mainly in the innate immune response. Therefore, the focus of this study was to ...explore the alterations in the percentages of CD16+, and/or CD56+ lymphocytes, which are comprised of NK cells, and minority of CD56+CD3+ cells, in patients with metastatic colorectal cancer before or 2 months after the treatment with cetuximab-based regimens associated with the response to therapy. The changes in the percentages of lymphocytes and granulocytes in these patients were evaluated as well. We enrolled 50 patients with
metastatic colorectal cancer. Disease progression was observed in 11/50 patients (non-responders), while other patients achieved partial response or stable disease (responders). Control groups included up to 72 healthy individuals. A significant decrease in the percentages of CD56+ and CD16+CD56+ lymphocytes together with a significant decrease in the percentage of lymphocytes and an increase in the ratio of granulocyte to lymphocyte percentages were observed in patients with metastatic colorectal cancer before therapy, compared with those in the healthy individuals. In contrast to those in the responders, the percentage of CD16+ lymphocytes in the overall white blood cell pool was shown to be significantly decreased in the non-responders, together with a significantly decreased percentage of lymphocytes, a significantly increased percentage of granulocytes, and an increased ratio of granulocyte to lymphocyte percentages before treatment compared with those in the healthy controls. Two months after the initiation of the treatment, significantly decreased percentages of CD16+, CD56+, and CD16+CD56+ lymphocytes were observed in patients, compared with those determined in the healthy controls. The same changes in the amounts of circulating immune cells were also observed in the responder subgroup, but the percentages of CD16+, CD56+, and CD16+CD56+ lymphocytes 2 months after treatment in the non-responder group did not differ significantly in comparison with healthy individuals. Considerable alterations of immune cell percentages observed in patients with metastatic colorectal cancer with disease progression indicate that the assessment of peripheral white blood cell architecture before treatment initiation may be clinically relevant.
The concentrations of zinc (Zn), iron (Fe) and copper (Cu) in both human milk and infant formula were determined using a new sample preparation method, by inductively coupled plasma - optical ...emission spectometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). Human milk samples were diluted in ultrapure water. The infant formula of powder samples (suitable for an infant 1-6 months of age) and standard reference material (SRM-1849) were analyzed in parallel. The results have shown that FAAS method was more sensitive for Fe determination in human milk while ICP-OES was more sensitive for both Zn and Cu detection. The limit of quantification for both Zn and Cu was 5 μg L-1 and 10 μg L-1 for Fe and the recovery for Zn, Fe and Cu was ranged from 90% to 94%, 97% to 103% and 90% to 102%, respectively. Mean concentrations of Zn, Fe, and Cu in human milk samples were 5.35, 0.47 and 0.83 mg L-1, respectively while these values in infant formula were ranged from 3.52-4.75 mg L-1, 3.37-4.56 mg L-1 and 0.28-0.41 mg L-1, respectively. Despite the sample complexity, the proposed method using dilution of milk samples with water was simple, rapid, effective and accurate. ICP-OES was a better method for Zn determination while FAAS was a better method for Fe determination. In the case of Cu both methods were comparable.
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