Theoretical and experimental analysis of the fine structure and hyperfine structure in the configurations 5p6s and 5p6p of the antimony II spectrum

From 17 transitions in the singly ionized Sb II spectrum the hyperfine structure (A andB splitting constants) of the complete excited configurations 5p6s and 5p6p were determined by means of optical interference spectroscopy. In addition, a theoretical analysis both of the fine structure and also of the hyperfine structure was carried out (in the case of 5p6p of the general typenpn′p for the first time in literature). For the 3 levels 5p6p ³ P ₁, 5p7p ³ D ₂ and 5p6p ¹ P ₁ a different classification was found and consistent values for the fine structure parameters, mixing coefficients and single electron hyperfine structure splitting parametersa _nl ^ik andb _nl ^ik were obtained. The three new determinations in Sb II of the quadrupole moment (in barn) of¹²¹Sb (Q(5p6s)=?0.55(5);Q(5p6p)=?0.57(5) from the 5p-electron andQ(5p6p)=?0.7(2) from the 6p-electron) are well agreeing with each other but differ to former values from SbI. The core polarization and isotope shift of the lines, however, are compatible with our former results in SbI.     

Copolymerization of acrylic acid to nylon-6 by trapped radicals—I. Vapour phase grafting

Film of nylon-6 has been γ-irradiated in vacuo to various doses D. Grafting has been effected by subsequent exposure in vacuo to vapour at 50° of composition 9.1 wt% acrylic acid and 90.9 wt% water. Determinations have been made of total vapour uptake as well as the individual swellings due to monomer and water. For D ? ca. 2 Mrad, the initial rate of grafting R_g increased with D in accord with R_g ∝ D^β with β = 0.45 ± 0.05, thus suggesting bimolecular chain termination. However, for D ? ca. 2 Mrad, there is no further increase in R_g. This is attributed in part to the fact that the radical yield is proportional to dose only for D ? ca. 2.5 Mrad. Diffusion controlled grafting has been predicted elsewhere to be characterized by β = 0.67. Grafting proceeds from the surface and the initial stages are concluded to be essentially free from diffusion control, since (a) β ≠ 0.67, (b) the rate of uptake of monomer vapour >R_g and (c) a large change in film thickness yields only a very small change in R_g.     

Effect of Soil Type: Qualitative and Quantitative Analysis of Phytochemicals in Some Browse Species Leaves Found in Savannah Biome of South Africa

In semi-arid regions, browse plant species are used as feed and for medicinal purposes for both animals and humans. The limitation of the utilization of these species to medicinal purposes or as feed for livestock is a lack of knowledge on the concentration level of phytochemicals and other bioactive compounds found in these plants. The study sought to assay the qualitative and quantitative bioactive constituents of some browse species found in the savannah biome of South Africa, viz. Adansonia digitate, Androstachys johnsonii, Balanites maughamii, Berchemia discolor, Berchemia zeyheri, Bridelia mollis hutch, Carissa edulis, Catha edulis, Colophospermum mopane, Combretum Imberbe, Combretum molle, Combretum collinum, Dalbergia melanoxylon, Dichrostachys cinerea, Diospros lycioides, Diospyros mespiliformis, Euclea divinorum, Flueggea virosa, Grewia flava, Grewia flavescens, Grewia monticola, Grewia occidentalis, Melia azedarach, Peltophorum africanum, Prosopis velutina, Pseudolachnostylis maprouneifolia, Pterocarpus rotundifolius, Schinus molle, Schotia brachypetala, Sclerocarya birrea, Searsia lancea, Searsia leptodictya, Searsia pyroides, Senegalia caffra, Senegalia galpinii, Senegalia mellifera, Senegalia nigrescens, Senegalia polyacantha, Strychnos madagascariensis, Terminalia sericea, Trichilia emetic, Vachellia erioloba, Vachellia hebeclada, Vachellia karroo, Vachellia nilotica, Vachellia nilotica subsp. Kraussiana, Vachellia rechmanniana, Vachellia robusta, Vachellia tortilis, Vachellia tortilis subsp. raddiana, Vangueria infausta, and Ziziphus mucronata. These browse species’ leaf samples were harvested from two provinces (Limpopo and North-West) of South Africa. The Limpopo province soil type was Glenrosa, Mispah, and Lithosols (GM-L), and the soil types in the North-West Province were Aeolian Kalahari Sand, Clovelly, and Hutton (AKS-CH). The harvested browse samples were air dried at room temperature for about seven days and ground for analysis. The methanol and distilled water extracts of the browse species leaves showed the presence of common phytoconstituents, including saponins, flavonoids, tannins, phenols, cardio glycosides, terpenoids, and phlobatannins, as major active compounds in browse species leaves. In the quantitative analysis, phytochemical compounds, such as soluble phenols, insoluble tannins, and condensed tannins, were quantified for common species found in both sites. Two-way ANOVA and multivariate analysis were used to test soil type and species effect on soluble phenols, insoluble tannins, and condensed tannins of woody species. Dichrostachys cinerea (0.1011% DM) in GM-L soil type and Z. mucronata (0.1009% DM) in AKS-CH soil type showed the highest (p < 0.05) concentration of soluble phenols. In AKS-CH soil type, D. cinerea (0.0453% DM) had the highest insoluble tannins concentration, while V. hebeclada had the lowest (0.0064% DM) insoluble tannins content. Vacchelia hebeclada had lower (p < 0.05) condensed tannins concentration levels than all other browse plants in both soil types. Under multivariate analysis tests, there was a significant effect (p < 0.001) of soil type, species, and soil type x species interaction on soluble phenols, insoluble tannins, and condensed tannins of woody species. In this study, most of the woody species found in GM-L soil type showed a lower amount of tannins than those harvested in AKS-CH soil type. There is a need to identify the amount of unquantified phytochemicals contained in these browse species and valorize the high-bioactive-compound browse species to enhance and maximize browsing of these browse species for animal production.     

Synthesis of S,S-dialkyl-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)sulfoximides and specificities of their base-catalyzed intramolecular heterocyclizations into naphtho[1,2,3-cd]-indol-6(2H)-ones

Heating of 6H-anthra[1,9-cd][1,2]oxazol-6-ones with dialkyl sulfoxides in sulfolane gave S,S-dialkyl-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)sulfoximides which underwent cyclization to naphtho-[1,2,3-cd]indol-6(2H)-one derivatives on heating in boiling tetrahydrofuran in the presence of sodium methoxide. p-Toluenesulfinic acid was isolated as by-product in the cyclization of S-methyl-S-(4-methylphenyl)-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)sulfoximide. The heterocyclizations of S,S-dipropyl- and S,S-dibutyl-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)sulfoximides to 1-ethyl- and 1-propylnaphtho[1,2,3-cd]-indol-6(2H)-ones were accompanied by formation of the corresponding 1-[1-hydroxyethyl(propyl)]naphtho-[1,2,3-cd]indol-6(2H)-ones.     

Hyperfine structure in the configurations4f 4 6s 2 and4f 4 5d 6s of Nd I

The high resolution laser-atomic-beam technique was used to investigate the hyperfine structure in Nd I 4f ⁴6s ^{2 5} I,⁵ F,⁵ S and 4f ⁴5d6s ⁷ L,⁷ K,⁷ I,⁷ H. The metastable states were populated by an arc discharge burning in the atomic beam. The measured hyperfine constantsA andB of the levels of 4f ⁴6s ² and 4f ⁴5d6s allow a parametric analysis to be performed using the effective tensor operator formalism. The experimental radial integrals of the 4f and 5d electrons fit with those of the other lanthanides. The 4f radial integrals are in agreement with values of optimized Hartree-Fock-Slater calculations. The spectroscopic quadrupole moments of¹⁴³Nd and¹⁴⁵Nd are deduced from the 4f parameters:Q _I =?0.610(21) b and ?0.314(12) b, respectively. TheQ _I resulting from the 5d parameter are in satisfactory agreement with these values. The hyperfine anomaly due to thes electron in 4f ⁴5d 6s amounts to about 1%.     

Theoretical study of the static Jahn-Teller effect—III. Type of vibronic coupling in hexahalo complexes

Three types of vibronic coupling in hexacoordinate complexes are compared: the T_ig−(a_1g + e_g) type in the group O_h, the E_g−(α_1g + e_g) type in the group D_3d, and the E_g−(α_1g + b_1g) type in the group D_4h. It is shown that the group with the highest symmetry (O_h) does not imply the best model of vibronic coupling. Numerical applications were obtained for 29 complexes of the MX^q₆ type having a triply degenerate electronic state in an octahedral geometry on the CNDO-UHF level of the MO-LCAO-SCF method. Characteristics of these Jahn-Teller active systems are calculated and discussed.     

A model for transitional plane Couette flow

A simplified model of plane Couette flow is derived by means of a cross-stream (y) Galerkin expansion in terms of trigonometric functions appropriate for idealized stress-free boundary conditions at the plates. A set of partial differential equations is obtained, governing the in-plane (x–z) space-dependence of a velocity field taken in the form: u=U₀(x,z,t)+[1+U₁(x,z,t)]sin(πy/2), v=V₁(x,z,t)cos(πy/2), w=W₀(x,z,t)+W₁(x,z,t)sin(πy/2). Beyond Lorenz-like Waleffe's modeling (Waleffe 1997), this Swift–Hohenberg type of approach is expected to give an access to the microscopic mechanism of spatiotemporal intermittency typical of the transition to turbulence in plane Couette flow (Pomeau 1986, Bergé et al. 1998).     

Molar excess volumes of ternary mixtures of nonelectrolytes

Molar excess volumes V^E_ijk of methylenebromide i + pyridine j + β-picoline (k, cyclohexane (i) + pyridine (j) + β-picoline(K), benzene(i)+toluene(j)+1,2-dichloroethane(k), benzene(i) + 0-xylene(j) + 1,2-dichloroethane(k) and benzene(i) + p-xylene(j) + 1,2-dichloroethane(k) mixtures have been determined dilatometrically at 298.15 K. The data have been examined in terms of Sanchez and Lacombe theory and the graph-theoretical approach, and it is found that they are described well by the latter. Self- and cross-volume interaction coefficients V_jk, V_jjk and V_jkk, etc., have also been evaluated and the values utilised to study molecular interactions between the jth and kth molecular species in the presence of the ith in these i + j + k mixtures.     

Engineering of Yeast Old Yellow Enzyme OYE3 Enables Its Capability Discriminating of (E)-Citral and (Z)-Citral

The importance of yeast old yellow enzymes is increasingly recognized for direct asymmetric reduction of (E/Z)-citral to (R)-citronellal. As one of the most performing old yellow enzymes, the enzyme OYE3 from Saccharomyces cerevisiae S288C exhibited complementary enantioselectivity for the reduction of (E)-citral and (Z)-citral, resulting in lower e.e. value of (R)-citronellal in the reduction of (E/Z)-citral. To develop a novel approach for the direct synthesis of enantio-pure (R)-citronellal from the reduction of (E/Z)-citral, the enzyme OYE3 was firstly modified by semi-rational design to improve its (R)-enantioselectivity. The OYE3 variants W116A and S296F showed strict (R)-enantioselectivity in the reduction of (E)-citral, and significantly reversed the (S)-enantioselectivity in the reduction of (Z)-citral. Next, the double substitution of OYE3 led to the unique variant S296F/W116G, which exhibited strict (R)-enantioselectivity in the reduction of (E)-citral and (E/Z)-citral, but was not active on (Z)-citral. Relying on its capability discriminating (E)-citral and (Z)-citral, a new cascade reaction catalyzed by the OYE3 variant S296F/W116G and glucose dehydrogenase was developed, providing the enantio-pure (R)-citronellal and the retained (Z)-citral after complete reduction of (E)-citral.     

Helicity of N,N′-diaryl-trans-1,2-diaminocyclohexane derivatives. Implications for molecular helicity manipulations

Derivatives of trans-1,2-diaminocyclohexane (DACH), useful as chiral ligands, scaffolds and building blocks, differ in their conformation. The conformation of N,N′-diaryl-DACH derivatives was studied by the semiempirical and DFT computational methods and by exciton-coupled circular dichroism. It was found that, contrary to M-helical N,N′-diimine, N,N′-diimide and N,N′-diamide derivatives, the aromatic residues in N,N′-diphenyl derivatives are oriented to form a P-helix for the (R,R)-DACH absolute configuration. The helicity of the bis-aryl system is modified in the case of 1-naphthyl or 2-naphthyl derivatives. Further switching of helicity has been demonstrated by either protonation or mono-N-acetylation of N,N′-diaryl DACH derivatives.     

Toll-like Receptors Gene Expression in the Gastrointestinal Tract of Salmonella Serovar Pullorum-Infected Broiler Chicken

Salmonella enterica serovar Pullorum causes substantial mortality in chicks as well as results in persistent infection and vertical transmission in layer birds. An effective innate immune response in the early stages of infection could reduce bacterial colonization and mortality in chicks and persistency of infection in later stages. Toll-like receptors (TLRs), important components of innate immune response, plays a pivotal role in early recognition of pathogen as well as in the initiation of robust and specific adaptive immune response. In the present study, we quantified the expression levels of chicken TLRs (1LA, 1LB, 2A, 2B, 3, 4, 5, 7, 15, and 21) mRNA by quantitative real-time PCR in the gastrointestinal (GI) tissues (duodenum, jejunum, ileum, and cecum) of 3-day-old broiler chicks after 24 h of oral infection with S. enterica serovar Pullorum. We found significant upregulation of TLRs (TLR2, TLR4, TLR21) mRNA expressions in GI tract tissues after S. Pullorum infection. The exceptions were for TLR3 and TLR15 with decrease in the expression levels in the jejunum after infection. TLR4 gene expression was significantly (P?<?0.05) upregulated in the duodenum and ileum of infected chicks. Gene expression for some of the TLRs (TLR1LA, ILB, 2B, and TLR5) remained unchanged after infection with S. Pullorum in all the GI tissues studied. Most substantial change in gene expression was found for TLR21, being significantly (P?<?0.05) upregulated in all the tissues investigated. The differential expression levels of TLRs shed light on tailored innate immune response induced by S. Pullorum during the early stages of infection in chicks.     

Rearrangement with oxide ion transfer in reactions of 4-chloro-2-oxo-2,3-dihydrothiazole-5-carbaldehyde with ureas. cis-(Z)-trans-(E) isomerism of N-(2,4-dioxothiazolidin-5-ylidenemethyl)ureas

4-Chloro-2-oxo-2,3-dihydrothiazole-5-carbaldehyde reacted with monosubstituted ureas to give cis-(Z)-and trans-(E)-N-(2,4-dioxothiazolidin-5-ylidenemethyl)ureas via rearrangement involving oxide ion transfer, cis (Z) Isomers were formed in methanol or dimethylformamide, while both individual cis (Z) and trans (E) isomers and their mixtures were isolated in the reaction performed in acetic acid.     

Ultrasonic speed in compressed liquid by a sing-around method

A new apparatus for the measurement of ultrasonic speed in compressed liquid was constructed. The reliability of this instrument was confirmed by measuring the speeds in pure benzene in the ranges from 283.15 to 323.15 K and pressures up to near freezing pressure, and by comparing the results with literature values. The isentropic compressibilities κ_S were also determined using the experimental speeds and densities, and the results κ_S(u) were compared with those observed directly elsewhere κ_S(d) and those calculated thermodynamically κ_S(c) from (p, V_m, T). At atmospheric pressure, the present results, while agreeing with κ_S(u) reported in the literature, show differences from κ_S(d) and κ_S(c), while those for higher pressures close on a simple curve with κ_S(c).     

Electronic spectra of o-, m- and p-tolunitrile—substituent effect on internal rotation of the methyl group

The S₁ ← S₀ fluorescence excitation spectra and the S₁→S₀ dispersed fluorescence spectra of o-, m-and p-tolunitrile were measured in supersonic jets. Low-frequency bands due to internal rotation of the methyl group were observed in m- and p-tolunitrile. Observed band positions and relative intensities of the internal rotational bands were reproduced by a calculation using a free rotor basis set. From the analysis, the potential curve of the internal rotation was determined in both S₁ and S₀. It was found that the barrier height increases in going from S₀ to S₁ in m-tolunitrile, while it decreases in p-tolunitrile. In contrast, no low-frequency band was found in o-tolunitrile. It is concluded that the potential curve in o-tolunitrile does not change in going from S₀ to S₁. The change of the barrier height by electronic excitation in tolunitriles differs greatly from that observed in other toluene derivatives. It is suggested that the electronic properties of a substituent are important for the methyl rotation in the excited state.     

Enhanced Green Fluorescent Protein Expression in Pleurotus ostreatus for In Vivo Analysis of Fungal Laccase Promoters

The laccase family of Pleurotus ostreatus has been widely characterized, and studies of the genes coding for laccase isoenzymes in P. ostreatus have so far led to the identification of four different genes and the corresponding cDNAs, poxc, pox1, poxa1b and poxa3. Analyses of P. ostreatus laccase promoters poxc, pox1, poxa1b and poxa3 have allowed identification of several putative response elements, and sequences of metal-responsive elements involved in the formation of complexes with fungal proteins have been identified in poxc and poxa1b promoters. In this work, development of a system for in vivo analysis of P. ostreatus laccase promoter poxc by enhanced green fluorescent protein expression is performed, based on a poly ethylene glycol-mediated procedure for fungal transformation. A quantitative measurement of fluorescence expressed in P. ostreatus transformants is hereby reported for the first time for this fungus.     

Conversion-time curves in the diffusion-controlled free radical polymerization of styrene

In order to calculate conversion-time curve in radical polymerization, the termination rate constant for interacting polymer radicals with chain lengths n and s is written as: k_t,ns = k(ζ_n + ζ_s) where k ∝ exp(−0.40/v_f) (v_f: free volume), and ζ = 1 at n ⩽ n_c and ζ = (n_c/n)^1,5 at n ⩾ n_c + 1 (n_c: a critical chain length of polymer moving by reptation). The curves are applicable to the experimental data obtained from 20°C to 154°C in the thermal polymerization of styrene. Further, it is shown that the curves can be applied to the experimental data for polymerization in the presence of initiator.     

Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for N-tert-butoxycarbonylation of amines under solvent-free conditions at room temperature

Commercially available copper(II) tetrafluoroborate hydrate was found to be a highly efficient catalyst for chemoselective N-tert-butoxycarbonylation of amines with di-tert-butyl dicarbonate under solvent-free conditions and at room temperature. Various aromatic amines were protected as their N-tert-butyl carbamates in high yields and in short times. No competitive side reactions such as isocyanate, urea, and N,N-di-t-Boc formation was observed. Chemoselective N-tert-butoxycarbonylation was achieved with substrates bearing OH and SH groups. Chiral α-amino acid esters afforded the corresponding N-t-Boc derivatives in excellent yields.     

Antibacterial activity of N-quaternary chitosan derivatives: Synthesis, characterization and structure activity relationship (SAR) investigations

Quaternary N-(2-(N,N,N-tri-alkyl ammoniumyl and 2-pyridiniumyl) acetyl) derivatives of chitosan polymer, chitooligomer, and glucosamine (monomer) were synthesized for the purpose of investigating the structure activity relationship (SAR) for the antibacterial effect. Novel methods were used in the synthesis. The final chitosan and chitooligomer derivatives could thus be obtained in two steps without prior protection of the hydroxyl groups. However, in order to obtain chitosan derivatives with the bulky N,N-dimethyl-N-dodecyl- and N,N-dimethyl-N-butyl side chains three steps were needed, starting from 3,6-O-di-tert-butyldimethylsilyl chitosan (3,6-O-di-TBDMS chitosan) as the key intermediate. The quaternary ammoniumyl acetyl derivatives of glucosamine were synthesized from glucosamine or tetra-O-acetylglucosamine. N,N,N-trimethyl chitosan (TMC) was used as reference compound for investigation of antibacterial activity. Clinical Laboratory Standard Institute (CLSI) protocols were used to determine MIC and MLC for activity against clinically important Gram-positive strains Staphylococcus aureus (ATCC 25923), and S. aureus (MRSA) (ATCC 43300), and Gram-negative strains of Escherichia coli (ATCC 25922), P. aeriginosa (ATCC 27853) and Enterococcus facialis (ATCC 29212). The MIC values for the compounds ranged from 8 to ?8192 mg/L. In general the N-(2-(N,N-dimethyl-N-dodecyl ammoniumyl) acetyl) derivatives of chitooligomer and glucosamine monomer were more active against bacteria than derivatives with shorter alkyl chains. In contrast the N-(2-(N,N-dimethyl-N-dodecyl ammoniumyl) acetyl) derivatives of chitosan were less active than derivatives with N-(2-N,N,N-trimetylammoniumyl) acetyl or N-(2-(N-pyridiniumyl) acetyl) quaternary moiety. N,N,N-trimethyl chitosan (TMC) was the most active compound in this study.