RESUMEN
We use a combination of low temperature, high field magnetic circular dichroism, absorption, and emission spectroscopy with relativistic time-dependent density functional calculations to reveal a subtle interplay between the effects of chemical substitution and spin-orbit coupling (SOC) in a family of iridium(III) complexes. Fluorination at the ortho and para positions of the phenyl group of fac-tris(1-methyl-5-phenyl-3-n-propyl-[1,2,4]triazolyl)iridium(III) cause changes that are independent of whether the other position is fluorinated or protonated. This is demonstrated by a simple linear relationship found for a range of measured and calculated properties of these complexes. Further, we show that the phosphorescent radiative rate, k(r), is determined by the degree to which SOC is able to hybridize T(1) to S(3) and that k(r) is proportional to the inverse fourth power of the energy gap between these excitations. We show that fluorination in the para position leads to a much larger increase of the energy gap than fluorination at the ortho position. Theory is used to trace this back to the fact that fluorination at the para position increases the difference in electron density between the phenyl and triazolyl groups, which distorts the complex further from octahedral symmetry, and increases the energy separation between the highest occupied molecular orbital (HOMO) and the HOMO-1. This provides a new design criterion for phosphorescent iridium(III) complexes for organic optoelectronic applications. In contrast, the nonradiative rate is greatly enhanced by fluorination at the ortho position. This may be connected to a significant redistribution of spectral weight. We also show that the lowest energy excitation, 1A, has almost no oscillator strength; therefore, the second lowest excitation, 2E, is the dominant emissive state at room temperature. Nevertheless the mirror image rule between absorption and emission is obeyed, as 2E is responsible for both absorption and emission at all but very low (<10 K) temperatures.
RESUMEN
The conformational stabilities of the transition metal complex of Zn (en)3Cl2 were studied using density functional theory (DFT). Deformational potential energy profiles (PEPs), and pathways between the different isomeric conformational energies were calculated using DFT/B3LYP/6-31G. The relative conformational energies of Delta(lambdalambdalambda), Delta(lambdalambdadelta), Delta(lambdadeltadelta) and Delta(deltadeltadelta) are 10.48, 7.08, 3.56, and 0.0 kcal/mol, respectively, which are small compared to the barrier heights for reversible phase transitions (49.56, 49.55, 49.52 kcal/mol, respectively). Frequency assignment was carried out by decomposing Fourier transform infrared (FTIR) spectra using Gaussian and Gaussview. The theoretical IR and vibrational dichroism spectroscopy (VCD) absorption spectra are presented for all conformations within the range of 400-3,500 cm(-1).
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Cloruros/química , Dicroismo Circular , Etilenodiaminas/química , Modelos Moleculares , Compuestos de Zinc/química , Dicroismo Circular/métodos , Estructura Molecular , Espectroscopía Infrarroja por Transformada de Fourier/métodos , TermodinámicaRESUMEN
The structure, stability, and the IR, and EPR spectroscopic properties of bis(methoxyacetato)diaquo-copper(II) were studied both experimentally using FT-IR and theoretically using B3LYP/6-31G**, B3LYP/6-311G, BWP91/6-31G** methods. The same approaches were used to calculate the harmonic frequencies and to compare them to the experimental solid state values. The g-tensors are calculated using the NMR/GIAO computational method.
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Simulación por Computador , Cobre/química , Compuestos Organometálicos/química , Espectroscopía de Resonancia por Spin del Electrón/métodos , Estructura Molecular , Espectroscopía Infrarroja por Transformada de Fourier/métodosRESUMEN
BACKGROUND: Insufficient tissue oxygenation is a likely contribution to weak, inco-ordinate human uterine contractile activity characteristic of prolonged, dysfunctional labour. However, the direct effects of hypoxia on human myometrial contractility has, surprisingly, not yet been detailed. Therefore, we report the influence of hypoxia on spontaneous and agonist-induced carbachol, prostaglandin (PGF2alpha), and oxytocin contractions of myometria from nonpregnant and pregnant women. MATERIALS AND METHODS: Uterine biopsies were obtained from pregnant women at term undergoing elective Caesarean section and nonpregnant women undergoing hysterectomy. Myometrial strips were equilibrated at 37 degrees C in normoxic physiological salt solution (95% air/5% CO(2)) and the influence of hypoxia (95% N(2)/5% CO(2)) on contractility was investigated. RESULTS: Hypoxia resulted in a significant reduction in spontaneous contractile function; nonpregnant tissue was less resistant to the deleterious effects of hypoxia. Agonist-induced contractions, while being more resistant to hypoxia than spontaneous contractions, were also significantly inhibited. In myometria of pregnant women the PGF2alpha- or oxytocin-induced contractility was more resistant to hypoxia than carbachol. Finally, the inhibitory actions of hypoxia were exacerbated with repeated oxytocin administration with a more severe effect on contractile integral than on initial phasic contraction amplitude. CONCLUSIONS: We detail, for the first time, the effects of hypoxia on contractility of human myometria from nonpregnant and pregnant women. Physiologically important uterotonic agents are more resistant to the effects of hypoxia than spontaneous contractions although repeated stimulation with oxytocin during hypoxia results in progressively less force. The results indicate that if significant hypoxia occurs in vivo then it is a likely contributory factor to the pathways underlying prolonged dysfunctional labour.
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Hipoxia/fisiopatología , Parto/fisiología , Contracción Uterina/fisiología , Adulto , Carbacol/farmacología , Cesárea , Agonistas Colinérgicos/farmacología , Dinoprost/farmacología , Femenino , Humanos , Histerectomía , Persona de Mediana Edad , Oxígeno/fisiología , Oxitócicos/farmacología , Oxitocina/farmacología , Embarazo , Técnicas de Cultivo de Tejidos , Contracción Uterina/efectos de los fármacosRESUMEN
OBJECTIVE: To assess the prevalence of infestations of lice in sheep flocks and to survey control practices for lice in South Australia DESIGN: A total of 201 managers of sheep flocks, 75 chosen randomly from the high rainfall zone (HR), 76 from the cereal sheep zone (CS) and 50 from the pastoral zone (PA), were surveyed by telephone interview. PROCEDURE: Interviews were conducted between May 19 and May 25, 1999, according to a set questionnaire. Information was collected on presence of lice at last shearing, control practices for lice, factors important for gaining good effect from chemical treatments, sources of information on control practices and property details. Survey results were analysed by agricultural region. RESULTS: The apparent state prevalence of flocks infested with lice was 21%, with 13% infested in the HR, 21% in the CS and 25% in the PA. Ninety one percent of managers claimed to take precautions to prevent the introduction of lice and 91% routinely checked their flocks for lice. Seventy eight percent treated their sheep for lice annually and 85% had treated within the last 12 months. Of those treating in the last year, 69% had used a backline application, 16% had used a shower dip and 17% had used plunge dipping. Only 4% of producers used a long wool treatment. Synthetic pyrethroid (SP) based products were used by 50% of producers who used backline treatments in the preceding 12 months, compared to 42% and 8% for insect growth regulator and organophosphorous (OP) based products, respectively. Only 34% of managers identified SP-based products as having potential resistance problems. Of those producers who used shower or plunge dips in the last 12 months, 75% used an OP based product. Rural newspapers and magazines were by far the most commonly noted source of information for the control of lice on sheep.
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Crianza de Animales Domésticos/estadística & datos numéricos , Infestaciones por Piojos/veterinaria , Enfermedades de las Ovejas/epidemiología , Enfermedades de las Ovejas/prevención & control , Crianza de Animales Domésticos/métodos , Animales , Infestaciones por Piojos/epidemiología , Infestaciones por Piojos/prevención & control , Phthiraptera , Prevalencia , Lluvia , Ovinos , Enfermedades de las Ovejas/etiología , Australia del Sur/epidemiología , Encuestas y Cuestionarios , LanaRESUMEN
Polarized absorption and emission spectra of trigonal single crystals of an Er(III) complex coordinated to a heptadentate tripodal ligand are reported at temperatures between 8 and 298 K. The assigned energy levels below the onset of ligand absorption (< 25 000 cm(-1)) are fitted to a parametrized electronic Hamiltonian. The C(3) site symmetry of the Er(III) ion requires eight parameters for a full description of the ligand field within a one-electron operator description. This compound shows unusually large splittings of the multiplets, and the fitted parameters imply that this heptadentate ligand imparts the largest ligand field reported for an Er(III) complex. The ligand field was also interpreted within the angular overlap model (AOM). We derive the AOM matrix to include both sigma and anisotropic pi bonding and show that a useful description of the C(3) ligand field can be made using only five parameters. The success of the AOM description is encouraging for applications on isomorphous complexes within the lanthanide series and in describing the ligand field of low-symmetry complexes with less parameters than in the usual spherical harmonic expansion.
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A series of novel macrocyclic tetraaza ligands that incorporate a naphthalene moiety as a photoactive chromophore have been prepared and structurally characterized as their Cu(II) complexes. Variable-temperature photophysical studies have concluded that the luminescence quenching evident in the Cu(II) complexes is due to intramolecular electronic energy transfer (EET). In their free-base forms, these ligands undergo reductive luminescence quenching via photoinduced electron transfer (PET) reactions, with proximate amine lone pairs acting as electron donors. Consequently, the emission behavior can be modulated by variations in pH and/or the presence of other Lewis acids such as Zn(II).
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The mixed-halide compound CsCdBrCl2 is studied by X-ray diffraction and by using the Ni(II) ion as an optical probe. Low-temperature absorption, luminescence, and EXFAS spectra of the Ni(II) impurity are recorded. The structure of CsCdBrCl2 is shown to consist of corner-sharing [Cd3X12]6- trimers. Each trimer has a structure of three face-sharing octahedra Cl3CdX3CdX3CdCl3 where X has an equal probability of being a Br- or a Cl- ion. This equal occupancy on the bridging halide positions occurs over the whole crystal rather than within each [Cd3X12]6- trimer unit. Optical spectroscopy shows that the Ni(II) ion exists in all possible [NiBrxCl6 - x]4- isomeric forms (x = 0, 1, ..., 6). The energy of the 3A2g-->1A1g transition is a linear function of x, due to the change in inter-electron repulsion through the differing covalencies of the ligand compositions. The energy of this transition can be varied over 2750 cm-1. The inhomogeneous broadening that results from the halide disorder is discussed from the point of view of the variation of ligand-field strength and inter-electron repulsion. A model including a differential nephelauxetic effect is required to explain the energies of the ligand-field states.
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Team teaching is a strategy which offers an alternative to traditional single teacher methods. However, little has been written about its use in nurse education. This paper examines team teaching and its rationale, discussing possible advantages and disadvantages. The use of this strategy as a means of teaching communication skills to Registered Mental Nurse (RMN) students is described and basic principles related to team teaching are offered as guidelines to enable others to implement this approach in a variety of subject areas.
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Comunicación , Enfermería Psiquiátrica/educación , Enseñanza/métodos , Humanos , Enseñanza/normasAsunto(s)
Antinematodos/uso terapéutico , Bencimidazoles/uso terapéutico , Levamisol/uso terapéutico , Infecciones por Nematodos/veterinaria , Enfermedades de las Ovejas/tratamiento farmacológico , Animales , Antinematodos/farmacología , Bencimidazoles/farmacología , Resistencia a Medicamentos , Heces/parasitología , Levamisol/farmacología , Nematodos/efectos de los fármacos , Infecciones por Nematodos/tratamiento farmacológico , Infecciones por Nematodos/parasitología , Recuento de Huevos de Parásitos/veterinaria , Lluvia , Distribución Aleatoria , Ovinos , Enfermedades de las Ovejas/parasitología , Australia del SurRESUMEN
The Wilmer Information System is a computerized medical information system used for the storage and retrieval of data pertaining to patient demographics, diagnosis, and therapy. The heart of the system is an expandable, hierarchical code based on International Classification of Diseases, 9th Revision (ICD-9) diagnosis codes and Physicians' Current Procedural Terminology procedure codes. Customized coding sheets containing highly specific diagnosis and procedure codes have been designed for each subspecialty area in ophthalmology. Interactive database management software facilitates data entry and retrieval. The system can be used to search for patients who meet very specific criteria, or to produce cumulative visit reports and summary statistics.
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Sistemas de Información , Oftalmología , Computadores , Sistemas de Administración de Bases de Datos , Oftalmopatías/diagnóstico , Oftalmopatías/terapia , Humanos , Programas InformáticosRESUMEN
A factorial-design survey was performed to determine the prevalence of specific antibody against Toxoplasma in young and adult sheep from 6 areas in 3 different geoclimatic zones in South Australia. Serum samples obtained from 1,159 sheep belonging to 59 flocks were tested by a conventional indirect haemagglutination test (IHAT) as well as by an enzyme-linked immunosorbent assay (ELISA) which used class-specific conjugates to detect both IgG and IgM against Toxoplasma. Titres greater than 64 were detected in 7.4%, 9.2% and 25.2% of the sheep by the IHAT, IgG-ELISA and IgM-ELISA respectively. A significant positive correlation was found between the results of the IgG-ELISA and the IHAT with identical results obtained for 1,050 samples. Antibody detected by all 3 tests was more prevalent and higher in titre in adult sheep than in lambs as well as in sheep from Kangaroo Island than in those from mainland South Australia. Although the regional differences in prevalence suggested a relationship with climate, no significant correlations were detected between the prevalence results and any single climatic factor; namely, average annual rainfall, average annual evaporation or mean temperature range.
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Anticuerpos/análisis , Enfermedades de las Ovejas/epidemiología , Toxoplasma/inmunología , Toxoplasmosis Animal/epidemiología , Animales , Formación de Anticuerpos , Australia , Ensayo de Inmunoadsorción Enzimática , Pruebas de Hemaglutinación , Inmunoglobulina G/análisis , Inmunoglobulina M/análisis , Ovinos , Enfermedades de las Ovejas/inmunología , Toxoplasmosis Animal/inmunologíaRESUMEN
Bodyweight responses to subcutaneous injections of vitamin B12 and copper were investigated using Hereford calves in the southeast of South Australia, an area known to produce cobalt and copper deficient sheep. Calves were allocated to one of four groups: control; copper; vitamin B12; copper plus vitamin B12. Responses in bodyweight gain to vitamin B12, and to copper were obtained during the trial of one year. The results of biochemical analysis of blood, hair and faeces from calves and of dam's milk are reported. It is concluded that calves raised on cobalt-deficient pastures will require cobalt or vitamin B12 supplementation prior to weaning.