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91.
Marcin Pisarek Maria Janik-Czachor Tomasz Płociński Mariusz Łukaszewski 《Journal of Materials Science》2009,44(21):5701-5712
Rapidly quenched amorphous alloys—containing metallic or metalloid elements—are precursors for selective catalysts of many
technically important reactions. To increase their activity, various methods of material degradation occurring at the surface
and in the bulk of the rapidly quenched alloys have been used for promoting the catalytic performance of such materials. The
modifications of the structure, composition, and morphology of the substrate proved to be efficient in transforming inactive
metal alloy precursors into active and selective catalysts for hydrogenation, and dehydrogenation of organic compounds, as
well as for other processes like steam reforming of methanol. This article presents several examples of characterization of
such catalysts and discusses their selectivity and activity in a connection with physical and chemical properties of their
surfaces. Moreover, it is shown that scanning electron microscopy, Auger electron spectroscopy, scanning Auger microscopy,
and energy dispersive spectrometry allowed the local changes occurring during the activation process to be identified and
their implications for catalytic function to be considered. 相似文献
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93.
Marcin ?roda Katarzyna Cholewa-KowalskaMarek Ró?ański Marek Nocuń 《Optical Materials》2011,33(3):397-401
Glasses of different matrix (phosphate, borate, silicate and lead-silicate) were studied for their optical properties. The effect of Er dopant on transmittance and luminescence properties was presented. The significant “red shift” and “blue shift” of UV edge absorption were discussed based on the changes in the framework of the borate and phosphate glasses, respectively. It was showed that the integral intensity of the two main optical absorption transitions monotonically increases with the order: phosphate < borate < silicate < lead-silicate. Ellipsometric measurement was applied to obtain the refractive index of the glasses. The correlation between the shift of edge absorption and the change of refractive index was presented. Effect of glassy matrix on luminescence of Er3+ was discussed. 相似文献
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In this paper we present results of detailed spectroscopic studies of Tb3+ luminescence from BaF2:0.075 mol% Tb performed at Superlumi station of Hasylab, DESY, Hamburg and at Institute of Physics, N. Copernicus University, Torun, Poland (IF UMK Torun).We have measured UV/VUV excitation spectra of the dominant blue Tb3+ luminescence and emission spectra under excitation into various bands found from the excitation spectra. The excitation spectra are dominated by the two well known broad bands due to the parity and spin-allowed (SA) 4f8 → 4f75d transitions. The higher energy triple t-band and unresolved single e-band at lower energies are widely separated (10 Dq about 16,500 cm−1) reflecting the single d-electron energy in the high symmetry cubic crystal field with a relatively low contribution from the low symmetry component.In addition to these bands we have also detected a number of weaker bands at lower energy sides of both dominant SA bands. While the structured band with components at 252.8, 252.3, 250.4 and 248.4 nm clearly corresponds to the SF (spin-forbidden) band found earlier in LiYF4:Tb, the bands at 183, 178 and 172 nm have been never, to the best of our knowledge, reported before. We present arguments that these new bands are the SF counterparts of the triple SA t-band at about 158 nm. The d-f exchange energies for d(e) and d(t) electrons are different at 7779 and 8245 cm−1, respectively.Although the energy levels corresponding to the identified high and low spin (HS and LS) states of the 4f75d configuration are, in BaF2, well separated, there are no SA nor SF transitions generating d-f emission in BaF2:Tb. This is because the numerous 4f8 energy levels intercept the excitation energy from 4f75d levels leading to the well known blue and green Tb3+ 4f8 emissions. 相似文献
96.
Elbieta mudzka Klaudia Lustyk Monika Guch-Lutwin Barbara Mordyl Alicja Zakrzewska-Sito Pawe Mierzejewski Jolanta Jakowska Marcin Koaczkowski Jacek Sapa Karolina Pytka 《International journal of molecular sciences》2022,23(24)
Schizophrenia is a chronic mental illness, which remains difficult to treat. A high resistance to the available therapies, their insufficient efficacy, and numerous side effects are the reasons why there is an urgent need to develop new antipsychotics. This study aimed to assess the antipsychotic-like effects of JJGW08, a novel arylpiperazine alkyl derivative of salicylamide, in rodents. First, considering the JJGW08 receptor profile, we investigated the compound’s intrinsic activity towards dopamine D2 and serotonin 5-HT1A, 5-HT2A, and 5-HT7 receptors using functional assays. Next, we assessed the effect of JJGW08 on MK-801- and amphetamine-induced hyperlocomotion, its risk of inducing catalepsy and impairing motor coordination, as well as the anxiolytic-like effects in the four-plate and marble burying tests in mice. Finally, we investigated the antipsychotic-like properties of JJGW08 in rats using MK-801-induced hyperlocomotion and prepulse inhibition tests. We found that JJGW08 showed antagonistic properties at dopamine D2 and serotonin 5-HT1A, 5-HT2A, and 5-HT7 receptors. However, the effect on the 5-HT2A and 5-HT7 receptors was very weak. Moreover, the tested compound showed an antipsychotic-like effect in MK-801- and amphetamine-induced hyperlocomotion but not in a prepulse inhibition test in rats. Notably, JJGW08 demonstrated anxiolytic-like properties in both behavioral tests. Importantly, the compound did not induce catalepsy or motor coordination impairment in mice at antipsychotic-like doses. Our study suggests it is worth searching for new potential antipsychotics among arylpiperazine alkyl derivatives of salicylamide. 相似文献
97.
Lesaw Bernard Lahuta Joanna Szabliska-Piernik Karolina Staanowska Katarzyna Gowacka Marcin Horbowicz 《International journal of molecular sciences》2022,23(21)
The phytotoxicity of silver nanoparticles (Ag NPs) to plant seeds germination and seedlings development depends on nanoparticles properties and concentration, as well as plant species and stress tolerance degrees. In the present study, the effect of citrate-stabilized spherical Ag NPs (20 mg/L) in sizes of 10, 20, 40, 60, and 100 nm, on wheat grain germination, early seedlings development, and polar metabolite profile in 3-day-old seedlings were analyzed. Ag NPs, regardless of their sizes, did not affect the germination of wheat grains. However, the smaller nanoparticles (10 and 20 nm in size) decreased the growth of seedling roots. Although the concentrations of total polar metabolites in roots, coleoptile, and endosperm of seedlings were not affected by Ag NPs, significant re-arrangements of carbohydrates profiles in seedlings were noted. In roots and coleoptile of 3-day-old seedlings, the concentration of sucrose increased, which was accompanied by a decrease in glucose and fructose. The concentrations of most other polar metabolites (amino acids, organic acids, and phosphate) were not affected by Ag NPs. Thus, an unknown signal is released by small-sized Ag NPs that triggers affection of sugars metabolism and/or distribution. 相似文献
98.
Maria Bialik Joanna Proc Anna Zgadzaj Karolina Mulas Marzena Kuras Marcin Sobczak Ewa Oledzka 《International journal of molecular sciences》2022,23(22)
Thermosensitive liquid suppositories (LSs) carrying the model antihypertensive drug metoprolol tartrate (MT) were developed and evaluated. The fundamental purpose of this work was to produce, for the first time, liquid MT suppositories based on biodegradable nanoparticles and optimize their rheological and mechanical properties for prospective rectal administration. The nanoparticle system was based on a biodegradable copolymer synthesized by ring opening polymerization (ROP) of glycolide (GL) and L,L-lactide (LLA). Biodegradable nanoparticles loaded with the model drug were produced by the o/o method at the first stage of the investigation. Depending on the concentration of the drug in the sample, from 66 to 91% of MT was released over 12 h, according to first-order kinetics. Then, thermosensitive LSs with MT-loaded biodegradable nanoparticles were obtained by a cold method and their mechanical and rheological properties were evaluated. To adjust the thermogelling and mucoadhesive properties for rectal administration, the amounts of major formulation components such as poloxamers (P407, P188), Tween 80, hydroxypropylcellulose (HPC), polyvinylpyrrolidone (PVP), and sodium alginate were optimized. The in vitro release results revealed that more than 80% of the MT was released after 12 h, following also first-order kinetics. It was discovered that the diffusion process was dominant. The drug release profile was mainly governed by the rheological and mechanical properties of the developed formulation. Such a novel, thermosensitive formulation might be an effective alternative to hypertension treatment, particularly for unconscious patients, patients with mental illnesses, geriatric patients, and children. 相似文献
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