The Effect of Substitution of Mn by Pd on the Structure and Thermomagnetic Properties of the Mn1-xPdxCoGe Alloys (Where x = 0.03, 0.05, 0.07 and 0.1).

In the present paper, the influence of partial substitution of Mn by Pd on structure, thermomagnetic properties, and phase transitions in the MnCoGe alloys was investigated. The studies of phase constitution revealed an occurrence of the orthorhombic TiNiSi-type and hexagonal Ni2Ti- type phases. Deep analysis of the XRD pattern supported by the Rietveld analysis allowed us to notice the changes in lattice parameters and quantity of recognized phases depending on the Pd content. An increase of palladium in alloy composition at the expense of manganese induced a rise in the Curie temperature. The values of ΔSM measured for the variation of external magnetic field ~5 T equaled 8.88, 23.99, 15.63, and 11.09 for Mn0.97Pd0.03CoGe, Mn0.95Pd0.05CoGe, Mn0.93Pd0.07CoGe, and Mn0.9Pd0.1CoGe alloy, respectively. The highest magnetic entropy change ΔSM was observed for samples with Pd content x = 0.05 induced by magnetostructural transformation. The analysis of the n vs. T curves allowed confirmation of the XRD and DSC results of an occurrence of the first-order magnetostructural transition in Mn0.95Pd0.05CoGe and Mn0.93Pd0.07CoGe alloys samples.

Sex steroids in diploid and triploid gibel carp (Carassius gibelio) of both sexes in different phases of the reproductive cycle.

The changes in concentrations of 17ß-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT) in the gonads and plasma of diploid and triploid gibel carp (Carassius gibelio) from the Siemianowka Reservoir, the Vistula River drainage were quantified and compared using an enzyme immunoassay. The phase of gonad maturity was based on histological analysis and the gonadosomatic index. All fish had properly developed gonads in the pre-spawning, spawning and late spawning phases of the reproductive cycle in the fish collected in April, June and October, respectively. Diploid and triploid females and males did not differ in mean GSI in all reproductive phases. In October, ovaries of most females contained vitellogenic oocytes, testes had large numbers of spermatozoa. The hormone concentrations in both tissues depended mainly on the reproductive phase, but not on ploidy. The patterns of changes in E2 concentrations was similar in females and males. In the pre-spawning phase, diploid and triploid females showed differences in the concentrations of 11-KT in gonads and plasma, and T in plasma. Diploid males differed in pattern of T concentrations in gonads and plasma, while all males showed a similar pattern of 11-KT plasma concentrations. Spermatozoa observed in triploid males suggest that they participate in reproduction. Gibel carps, regardless of ploidy, had an extended period of reproduction, which makes this invasive species a potentially greater threat to native ichthyofauna. The sex androgen concentrations that differed between 2 n and 3 n females could be physiological factors potentially contributing to the coexistence of gynogenetic C. gibelio females and sexual diploids.

Effect of Sago Starch Modifications on Polystyrene/Thermoplastic Starch Blends.

The preparation of polystyrene/thermoplastic starch (PS/TPS) blends was divided into three stages. The first stage involved the preparation of TPS from sago starch. Then, for the second stage, PS was blended with TPS to produce a TPS/PS blend. The ratios of the TPS/PS blend were 20:80, 40:60, 60:40, and 80:20. The final stage was a modification of the composition of TPS/PS blends with succinic anhydride and ascorbic acid treatment. Both untreated and treated blends were characterized by their physical, thermal, and surface morphology properties. The obtained results indicate that modified blends have better tensile strength as the adhesion between TPS and PS was improved. This can be observed from SEM micrographs, as modified blends with succinic anhydride and ascorbic acid had smaller TPS dispersion in PS/TPS blends. The micrograph showed that there was no agglomeration and void formation in the TPS/PS blending process. Furthermore, modified blends show better thermal stability, as proved by thermogravimetric analysis. Water uptake into the TPS/PS blends also decreased after the modifications, and the structural analysis showed the formation of a new peak after the modification process.

Relation between Density and Compressive Strength of Foamed Concrete.

This study aims to obtain the relationship between density and compressive strength of foamed concrete. Foamed concrete is a preferred building material due to the low density of its concrete. In foamed concrete, the compressive strength reduces with decreasing density. Generally, a denser foamed concrete produces higher compressive strength and lower volume of voids. In the present study, the tests were carried out in stages in order to investigate the effect of sand-cement ratio, water to cement ratio, foam dosage, and dilution ratio on workability, density, and compressive strength of the control foamed concrete specimen. Next, the test obtained the optimum content of processed spent bleaching earth (PSBE) as partial cement replacement in the foamed concrete. Based on the experimental results, the use of 1:1.5 cement to sand ratio for the mortar mix specified the best performance for density, workability, and 28-day compressive strength. Increasing the sand to cement ratio increased the density and compressive strength of the mortar specimen. In addition, in the production of control foamed concrete, increasing the foam dosage reduced the density and compressive strength of the control specimen. Similarly with the dilution ratio, the compressive strength of the control foamed concrete decreased with an increasing dilution ratio. The employment of PSBE significantly influenced the density and compressive strength of the foamed concrete. An increase in the percentage of PSBE reduced the density of the foamed concrete. The compressive strength of the foamed concrete that incorporated PSBE increased with increasing PSBE content up to 30% PSBE. In conclusion, the compressive strength of foamed concrete depends on its density. It was revealed that the use of 30% PSBE as a replacement for cement meets the desired density of 1600 kg/m3, with stability and consistency in workability, and it increases the compressive strength dramatically from 10 to 23 MPa as compared to the control specimen. Thus, it demonstrated that the positive effect of incorporation of PSBE in foamed concrete is linked to the pozzolanic effect whereby more calcium silicate hydrate (CSH) produces denser foamed concrete, which leads to higher strength, and it is less pore connected. In addition, the regression analysis shows strong correlation between density and compressive strength of the foamed concrete due to the R2 being closer to one. Thus, production of foamed concrete incorporating 30% PSBE might have potential for sustainable building materials.

Influence of Sintering Temperature of Kaolin, Slag, and Fly Ash Geopolymers on the Microstructure, Phase Analysis, and Electrical Conductivity.

This paper clarified the microstructural element distribution and electrical conductivity changes of kaolin, fly ash, and slag geopolymer at 900 °C. The surface microstructure analysis showed the development in surface densification within the geopolymer when in contact with sintering temperature. It was found that the electrical conductivity was majorly influenced by the existence of the crystalline phase within the geopolymer sample. The highest electrical conductivity (8.3 × 10-4 Ωm-1) was delivered by slag geopolymer due to the crystalline mineral of gehlenite (3Ca2Al2SiO7). Using synchrotron radiation X-ray fluorescence, the high concentration Ca boundaries revealed the appearance of gehlenite crystallisation, which was believed to contribute to development of denser microstructure and electrical conductivity.

B Chromosomes and Cytogenetic Characteristics of the Common Nase Chondrostoma nasus (Linnaeus, 1758).

Supernumerary B chromosomes (Bs) are very promising structures, among others, in that they are an additional genomic compartment for evolution. In this study, we tested the presence and frequency of B chromosomes and performed the first cytogenetic examination of the common nase (Chondrostoma nasus). We investigated the individuals from two populations in the Vistula River basin, in Poland, according to the chromosomal distribution of the C-bands and silver nucleolar organizer regions (Ag-NORs), using sequential staining with AgNO3 and chromomycin A3 (CMA3). Furthermore, we analyzed the chromosomal localization of two rDNA families (45S and 5S rDNA) using fluorescence in situ hybridization (FISH) with rDNA probes. C. nasus individuals showed a standard (A) chromosome set consisting of 2n = 50: 12 metacentric, 32 submetacentric, and 6 acrocentric chromosomes (NF = 94). Fourteen out of the 20 analyzed individuals showed 1-2 mitotically unstable submetacentric B chromosomes of different sizes. Six of them, in 14.1% of the analyzed metaphase plates, had a single, medium-sized submetacentric B (Bsm) chromosome (2n = 51) with a heterochromatic block located in its pericentromeric region. The other seven individuals possessed a Bsm (2n = 51) in 19.4% of the analyzed metaphase plates, and a second Bsm chromosome (2n = 52), the smallest in the set, in 15.5% of metaphase plates, whereas one female was characterized by both Bsm chromosomes (2n = 52) in 14.3% of the analyzed metaphase plates. AgNORs, GC-rich DNA sites, and 28S rDNA hybridization sites were observed in the short arms of two submetacentric chromosome pairs of A set. The constitutive heterochromatin was visible as C bands in the centromeric regions of almost all C. nasus chromosomes and in the pericentromeric region of several chromosome pairs. Two 5S rDNA hybridization sites in the pericentromeric position of the largest acrocentric chromosome pair were observed, whereas two other such sites in co-localization on a smaller pair of NOR chromosomes indicate a species-specific character. The results herein broaden our knowledge in the field of B chromosome distribution and molecular cytogenetics of C. nasus: a freshwater species from the Leuciscidae family.

Post-thaw Addition of Caffeine and/or Pentoxifylline Affect Differently Motility of Horse and Donkey-Cryopreserved Spermatozoa.

To increase sperm motility, several molecules have been tested in mammals. Methylxanthines have shown effects on sperm motility, capacitation, and on in vitro fertilization processes. The aim of the study was to evaluate if the post-thaw addition of caffeine and/or pentoxifylline changes motility parameters of cryopreserved stallion and donkey spermatozoa. Straws derived from 14 horses and 7 donkeys were thawed and diluted in a milk-based extender to obtain the following final concentrations: CTR (control, no additives), CAF 5 (5 mM caffeine), CAF 10 (10 mM caffeine), PTX 5 (5 mM pentoxifylline), PTX 10 (10 mM pentoxifylline), CAF-PTX (5 mM caffeine and 5 mM pentoxifylline). Samples were evaluated immediately post-thaw and after 60 and 120 minutes of incubation at 37°C. In horses, overall total motility was significantly lower in CTR than in to CAF5, CAF-PTX, PTX5, PTX10, whereas progressive motility increased only in CAF5 and PTX5 (P < .05). No differences between control and treatments were seen for donkey semen. In CTR, during the first hour of incubation horses' sperm cells showed a larger decrease than donkeys' ones in all parameters (P < .05), except for lateral sperm head displacement. Thus, post-thaw motility and velocity decreased more sharply in horses than in donkeys. Caffeine and pentoxifylline-added post-thaw were able to increase the proportion of motile spermatozoa only for stallions and not for donkeys. Whether the improvement in post-thaw motility of equine spermatozoa may have an effect on in vivo or in vitro pregnancy rates remains to be determined.

Different cationic forms of (-)-cytisine in the crystal structures of its simple inorganic salts.

The crystal structures of 13 simple salts of cytisine, an alkaloid isolated from the seeds of Laburnum anagyroides, have been determined, namely cytisinium (6-oxo-7,11-diazatricyclo[7.3.1.02,7]trideca-2,4-dien-11-ium) bromide, C11H15N2O+·Br-, cytisinium iodide, C11H15N2O+·I-, cytisinium perchlorate, C11H15N2O+·ClO4-, cytisinium iodide triiodide, C11H15N2O+·I-·I3-, cytisinium chloride monohydrate, C11H15N2O+·Cl-·H2O, cytisinium iodide monohydrate, C11H15N2O+·I-·H2O, cytisinium nitrate monohydrate, C11H15N2O+·NO3-·H2O, hydrogen dicytisinium tribromide, C22H31N4O23+·3Br-, hydrogen dicytisinium triiodide, C22H31N4O23+·3I-, hydrogen dicytisinium triiodide diiodide, C22H31N4O23+·I3-·2I-, hydrogen dicytisinium bis(triiodide) iodide, C22H31N4O23+·2I3-·I-, cytisinediium (6-oxidaniumylidene-7,11-diazatricyclo[7.3.1.02,7]trideca-2,4-dien-11-ium) bis(perchlorate), C11H16N2O2+·2ClO4-, and cytisinediium dichloride trihydrate, C11H16N2O2+·2Cl-·3H2O. Cytisine has two potential protonation sites, i.e. the N atom of the piperidine ring and the carbonyl O atom of the pyridone ring. Three forms of the cytisinium cation were identified, namely the monocation, which is always protonated at the N atom, the dication, which utilizes both protonation sites, and the third form, which contains two cytisine moieties connected by very short and linear O...H...O hydrogen bonds, with an O...O distance of approximately 2.4 Å. This third form may therefore be regarded as a 3+ species, or sesqui-cation, and is observed solely in the salts with bromide, iodide or triiodide (heavier halogen) anions. The cation is quite rigid and all 19 cytisinium fragments in the studied series have very similar conformations. The crystal structures are determined mainly by Coulombic interactions and hydrogen bonds, and the latter form is determined by different networks. Additionally, some anion-π and lone-pair...π secondary interactions are identified in almost all of the crystal structures. Hirshfeld surface analysis generally confirms the role of different interactions in the determination of the crystal architecture.

Spectral and photophysical properties of cytisine in acetonitrile - Theory and experiment.

Spectral and photophysical properties of (-)-cytisine that is used as a smoking cessation aid, and which derivatives are promising tools in a treatment of neurological diseases, were investigated in acetonitrile, non-specifically interacting solvent with a polarity similar to water. The two chair conformers of cytisine were found the most stable in the ground state S0 and the lowest excited singlet state S1(π,π*), wherein axial one was characterized by a significantly larger abundance, fluorescence lifetime 0.15 ns and fluorescence quantum yield 0.008. The S1(π,π*) excited state of both cytisine conformers deactivated almost exclusively via internal conversion.

Spectral and Photophysical Behavior of Cytisine in n-Hexane. Experimental Evidence for the S1(n,π*) → S0 Fluorescence.

Spectral and photophysical properties of (-)-cytisine (the compound used as a smoking cessation aid and a potential drug in Alzheimer's and Parkinson's diseases) were investigated. The two conformers of cytisine, whose presence in the S0 state has been earlier proved by the NMR and IR methods as well as in theoretical calculation, in nonpolar n-hexane show a rarely observed prompt fluorescence from the S1(n,π*) excited state. This observation is unambiguously evidenced by very small radiative rate constants of these two emitting conformers, kF = 7.4 × 105 and 3.0 × 105 s-1. Their lifetimes in the S1(n,π*) state are relatively long, τS1 = 1.9 and 6.7 ns; therefore, their fluorescence quantum yield is relatively high ϕF ∼ 10-3. The long-wavelength band in the cytisine absorption originates from the excitation to the S2(π,π*) state, while the S1(n,π*) state is not observed in this spectrum. Thus, the excited state S2(π,π*) is manifested only in the absorption spectrum, while the excited state S1(n,π*) is seen only in the fluorescence spectrum, so cytisine in n-hexane is characterized by close lying (n,π*) and (π,π*) excited singlet states.

Complexing ability of (-)-cytisine--synthesis, spectroscopy and crystal structures of the new copper and zinc complexes.

For the first time the NMR spectra of quinolizidine alkaloid with Cu(II) are studied. Structures of new complexes of (-)-cytisine with Cu(+2) and Zn(+2) cations are visualized, discussed in detail and characterized by spectroscopic methods: ESI-MS, NMR, UV-vis, EPR and crystallographic methods. In solution metal coordinates through the protonated nitrogen atoms of secondary amino groups (in piperidine ring) of cytisine molecule. While in solid state the most stable structures of the complexes are those in which the coordination of Cu(II) and Zn(II) salts is realized solely through the lactam carbonyl oxygen atom.

The amide protonation of (-)-N-benzoylcytisine in its perchlorate salts.

The (13)C NMR spectrum of (-)-N-benzoylcytisine perchlorate does not show a double set of signals typical of amide compounds, although this effect has been observed for the other diamine derivatives of cytisine. This observation means that in solution there must be the state of equilibrium between two forms of the cation with the protonated amide groups. DFT calculations have indeed indicated two preferred tautomeric forms with protonated oxygen atoms of amide groups. In the solid state however, according to X-ray analysis of perchlorate and perchlorate hydrate of N-benzoylcytisine the oxygen atom of the amide group in the six-membered ring A is preferred protonation site as compared with the oxygen in benzoic moiety. (-)-N-benzoylcytisine salt is the first compound from among the known derivatives of quinolizidine alkaloids that are not N-oxides, in which in solid state only the oxygen atom at cyclic amide is protonated instead of nitrogen atom or oxygen in benzoic moiety.

Statistical Validation of Absolute Configuration Assignment in Vibrational Optical Activity.

Chiroptical spectroscopy usually requires theoretically computed spectra to assist in the elucidation of the absolute configuration of samples for which experimental spectra have been recorded. Due to the inherently different nature of these two types of spectra, perfect agreement is quasi impossible. Several methods exist to quantify the degree of similarity between the two spectra, but rather limited work has been done to evaluate the robustness of the similarity between theory and experiment. In this work, a novel method is described to determine the statistical significance of the numerical degree of similarity between experimental and calculated vibrational circular dichroism spectra and to offer valuable support for performing absolute configuration assignments. The approach is successfully applied to a number of quinolizidine alkaloids.

[Crystal and molecular structure of cytisine salts]. / Struktura krysztalów i czasteczek serii soli cytyzyny.

Cytisine is an alkaloid of plant origin. It is a toxic substance, obtained on an industrial scale from Laburnum anagyroides also known as common laburnum. Today is used in the preparation of anti-smoking products as an agonist of nicotinic receptors nAChR-alpha4beta2. Thanks to crystallographic methods we can examine and describe with high accuracy the actual structure of complex chemical compounds. This work aims to present a series of tests carried out on crystals of cytisine salts, after a prior isolation of cytisine from the seeds of laburnum anagyroides.

Electron impact mass spectral study of halogenated N-acetyl- and N-propionylcytisines.

(-)-Cytisine and its derivatives, characterised by high affinity to neuronal nicotinic acetylcholine receptors with specificity for the α4ß2 subtype, have been shown to be important probes in central nervous system (CNS) research. Electron impact mass spectral (EI-MS) fragmentations of halogenated derivatives of N-acetylcytisine and N-propionylcytisine have been investigated. Detailed fragmentation pathways have been identified for all significant ions including a few characteristic fragment ions. The principal mass spectral fragmentation routes of iodine and bromine compounds have been determined on the basis of low (EI), high resolution (HRD) and B(2)/E linked scan mass spectra as well as linked scans at constant B/E.

Facile synthesis of 3-nitro-2-substituted thiophenes.

A new approach to 3-nitro-2-substituted thiophenes has been developed. Exposure of commercially available 1,4-dithane-2,5-diol to nitroalkenes in the presence of 20% triethylamine results in a tandem Michael-intramolecular Henry reaction to form the corresponding tetrahydrothiophene. Subsequent microwave irradiation on acidic alumina in the presence of chloranil effects the solvent free dehydration and aromatization to form 3-nitro-2-substituted thiophenes cleanly and rapidly. A simple workup procedure removes the requirement for purification by chromatography in most cases.

N-Methyl-2-thio-cytisine.

The rings of the three-ring cytisine system in the title compound [systematic name: (1R,5S)-1,2,3,4,5,6-hexa-hydro-1,5-methano-8H-pyrido[1,2-a][1,5]diazo-cine-8-thione], C(12)H(16)N(2)S, have planar [maximum deviation 0.0170 (7) Å], half-chair and chair conformations. In the crystal structure, relatively short and directional C-H⋯π inter-actions and weaker secondary C-H⋯S contacts join the mol-ecules into helical chains along the [001] direction.

Probes for narcotic receptor mediated phenomena. 37. Synthesis and opioid binding affinity of the final pair of oxide-bridged phenylmorphans, the ortho- and para-b-isomers and their N-phenethyl analogues, and the synthesis of the N-phenethyl analogues of the ortho- and para-d-isomers.

In the isomeric series of 12 racemic topologically rigid N-methyl analogues of oxide-bridged phenylmorphans, all but two of the racemates, the ortho- and para-b-oxide-bridged phenylmorphans 20 and 12, have remained to be synthesized. The b-isomers were very difficult to synthesize because of the highly strained 5,6-trans-fused ring junction that had to be formed. Our successful strategy required functionalization of the position para (or ortho) to a fluorine atom on the aromatic ring using an electron-withdrawing nitro group to activate that fluorine. The racemic N-phenethyl analogues 24 and 16 were moderately potent kappa-receptor antagonists in the [(35)S]GTPgammaS assay. We synthesized the N-phenethyl-substituted oxide-bridged phenylmorphans in the ortho- and para-d-oxide-bridged phenylmorphan series (51 and 52) which had not been previously evaluated using contemporary receptor binding assays to see whether they also have higher affinity for opioid receptors than their N-methyl relatives 46 and 47.

Synthesis and pharmacological effects of the enantiomers of the N-phenethyl analogues of the ortho and para e- and f-oxide-bridged phenylmorphans.

The N-phenethyl analogues of (1R*,4aR*,9aS*)-2-phenethyl-1,3,4,9a-tetrahydro-2H-1,4a-propanobenzofuro[2,3-c]pyridin-6-ol and 8-ol and (1R*,4aR*,9aR*)-2-phenethyl-1,3,4,9a-tetrahydro-2H-1,4a-propanobenzofuro[2.3-c]pyridin-6-ol and 8-ol, the ortho- (43) and para-hydroxy e- (20), and f-oxide-bridged 5-phenylmorphans (53 and 26) were prepared in racemic and enantiomerically pure forms from a common precursor, the quaternary salt 12. Optical resolutions were accomplished by salt formation with suitable enantiomerically pure chiral acids or by preparative HPLC on a chiral support. The N-phenethyl (-)- para-e enantiomer (1S,4aS,9aR-(-)-20) was found to be a mu-opioid agonist with morphine-like antinociceptive activity in a mouse assay. In contrast, the N-phenethyl (-)-ortho-f enantiomer (1R,4aR,9aR-(-)-53) had good affinity for the mu-opioid receptor (K(i) = 7 nM) and was found to be a mu-antagonist both in the [(35)S]GTP-gamma-S assay and in vivo. The molecular structures of these rigid enantiomers were energy minimized with density functional theory at the level B3LYP/6-31G* level, and then overlaid on a known potent mu-agonist. This superposition study suggests that the agonist activity of the oxide-bridged 5-phenylmorphans can be attributed to formation of a seven membered ring that is hypothesized to facilitate a proton transfer from the protonated nitrogen to a proton acceptor in the mu-opioid receptor.