RESUMEN
Main group element coordination polymers (MGE-CPs) are important compounds for the development of multifunctional materials. However, there has been a shortage of studies regarding their structural, optical, catalytic, mechanical, and antibacterial properties. This work presents an exhaustive study of a set of crystalline MGE-CPs obtained from bismuth and indium metals and iminodiacetate, 1,2,4,5-benzenetetracarboxylate, and 2,2'-bipyridine as building blocks. An in-depth topological analysis of the networks was carried out. Additionally, nanoindentation studies were performed on two representative low-dimensional compounds in order to find the relationships between their structural features and their intrinsic mechanical properties (hardness and elasticity). The solid-state photoluminescence (SSPL) properties were also studied in terms of excitation, emission, lifetimes values, and CIE chromaticites. Moreover, the heterogeneous catalytic activities of the compounds were evaluated with the cyanosilylation reaction using a set of carbonylic substrates under solvent-free conditions. Finally, the inhibitory effect of the Bi-CPs on the growth of microorganisms such as Escherichia coli, Salmonella enterica serovar Typhimurium, and Pseudomonas aeruginosa, which are associated with relevant infectious diseases, is reported.
RESUMEN
Recent hydrides-driven advent in the high-pressure phonon-mediated superconductivity motivates research on chemical elements which compound with hydrogen. It is desired that such elements should allow chemical pre-compression of hydrogen to assure the induction of the superconducting phase with the high transition temperature (T C). Herein, we present detailed theoretical insight into the properties of the superconducting state induced under pressure (p) in two of such component elements, namely selenium (Se) and tellurium (Te) at [Formula: see text] GPa and [Formula: see text] GPa, respectively. The assumed external pressure conditions allow us to conduct our analysis just above previously theoretically predicted bcc-fcc structural phase transition of Se and Te, and identify the possible associated discontinuity effect of the critical temperature. In particular, our numerical analysis is conducted within Migdal-Eliashberg formalism, due to the confirmed electron-phonon pairing mechanism and relatively high electron-phonon coupling constant in the materials of interest. We predict that T C values in Se and Te equal 8.13 K and 5.96 K, respectively, and mark the highest critical temperature values for these elements within the postulated fcc phase. Additionally, we supplement these results by the estimated maximum values of the superconducting energy band gap and the effective mass of electrons. We predict that all these parameters can be used as a guidelines for experimental observation of the critical temperature discontinuity and the corresponding bcc-fcc phase transition in Se and Te superconductors. Moreover, we show that the thermodynamics of superconducting phase in both elements may exhibit deviations from the conventional estimates of the Bardeen-Cooper-Schrieffer theory, and suggest existence of the strong-coupling and retardation effects. Finally, we note that our results can be also instructive for future screening of chemical elements for applications in superconducting hydrides.
RESUMEN
Here, the excellent thermal sensing capability of a multinuclear lanthanide polyoxometalate in the cryogenic region (<100 K) is presented for the first time. Up till now, no lanthanide polyoxometalates have been studied for their use as ratiometric luminescent thermometers. The investigated Tb3+ polyoxometalate cluster is doped with 1.6% (P1) and 8.4% (P2) of Eu3+ ions. When excited into the Mo-O charge transfer bands, at room temperature only the emission of the Eu3+ ions is observed suggesting a very efficient energy transfer between Mo-OâTb3+âEu3+. Only in the cryogenic region the emission of Tb3+ is also witnessed.
RESUMEN
Gadolinium dioxycarbonates co-doped with different visible emitting lanthanides were synthesized via a co-precipitation method using oxalic acid as a precipitating agent. Through XRD and DTA/TG investigations, the type-II hexagonal phase of the lanthanide dioxycarbonates was confirmed for all of the samples. The materials constitute of big agglomerates formed by submicrometrical particles. By varying the Ln3+ doping percentages and ratios and by changing the excitation wavelength the gadolinium dioxycarbonates activated with Sm3+, Eu3+, Tb3+, Dy3+ and Tm3+ showed tunable emission colors. Luminescence measurements were performed in order to determine: the luminescence behavior of the ions, the CIE coordinates, the CCT values and potential energy transfer. Interesting results were achieved upon exciting the samples at 351 nm and 365 nm demonstrating the possibility to obtain white emission in the dioxycarbonate matrix.
RESUMEN
Entomopathogenic fungi infect insects via penetration through the cuticle, which varies remarkably in chemical composition across species and life stages. Fungal infection involves the production of enzymes that hydrolyse cuticular proteins, chitin and lipids. Host specificity is associated with fungus-cuticle interactions related to substrate utilization and resistance to host-specific inhibitors. The soil fungus Conidiobolus coronatus (Constantin) (Entomophthorales: Ancylistaceae) shows virulence against susceptible species. The larvae and pupae of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae), Calliphora vomitoria (Linnaeus), Lucilia sericata (Meigen) (Diptera: Calliphoridae) and Musca domestica (Linnaeus) (Diptera: Muscidae) are resistant, but adults exposed to C. coronatus quickly perish. Fungus was cultivated for 3 weeks in a minimal medium. Cell-free filtrate, for which activity of elastase, N-acetylglucosaminidase, chitobiosidase and lipase was determined, was used for in vitro hydrolysis of the cuticle from larvae, puparia and adults. Amounts of amino acids, N-glucosamine and fatty acids released were measured after 8 h of incubation. The effectiveness of fungal enzymes was correlated with concentrations of compounds detected in the cuticles of tested insects. Positive correlations suggest compounds used by the fungus as nutrients, whereas negative correlations may indicate compounds responsible for insect resistance. Adult deaths result from the ingestion of conidia or fungal excretions.
Asunto(s)
Exoesqueleto/microbiología , Conidiobolus/fisiología , Dípteros/microbiología , Dípteros/fisiología , Animales , Quitinasas/metabolismo , Conidiobolus/enzimología , Dípteros/crecimiento & desarrollo , Femenino , Proteínas Fúngicas/metabolismo , Moscas Domésticas/crecimiento & desarrollo , Moscas Domésticas/microbiología , Moscas Domésticas/fisiología , Hidrólisis , Larva/crecimiento & desarrollo , Larva/microbiología , Larva/fisiología , Lipasa/metabolismo , Masculino , Péptido Hidrolasas/metabolismo , Pupa/crecimiento & desarrollo , Pupa/microbiología , Pupa/fisiologíaRESUMEN
This study evaluated the effect of electron beam irradiation on the cytotoxic activity of anthracycline antibiotics such as doxorubicin (DOX), epirubicin (EPI), and dunorubicin (DAU) in human acute lymphoblastic leukemia cell line CCRF-CEM and its multidrug-resistant variant CCRF-VCR1000 cell line characterized by the overexpression of ABCB1 gene. Drugs were irradiated at doses of 10 and 25 kGy. Data from EPR studies proved that the highest concentration of free radicals was found in DOX and that the number of stable free radicals is always greater after irradiation. In in vitro studies, a higher cytotoxic activity of irradiated DOX and EPI in multidrug-resistant CCRF-VCR1000 cells was observed. This tendency was maintained during the storage at 4 °C for 90 days. Changes in CCRF-CEM cells' viability were not dependent on the irradiation status and its dose and were only drug-concentration dependent in all measurement time points. It was proved that increased potency of 25 kGy e-beam irradiated drugs results from their enhanced proapoptotic activity. Apoptotic cell death observed in CCRF-VCR1000 cells treated with irradiated drugs was caspase-8, -9, and -3 dependent and related to the increased Bax/Bcl-2 ratio. No significant differences in the effects of irradiated and non-irradiated drugs on p53 and NFκB transcription factor level and their translocation to the nucleus were noted. Increased activity of the irradiated drugs was not dependent on ABCB1 level.
Asunto(s)
Apoptosis/efectos de los fármacos , Doxorrubicina/farmacología , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Múltiples Medicamentos/efectos de la radiación , Electrones , Epirrubicina/farmacología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Apoptosis/efectos de la radiación , Western Blotting , Caspasas/metabolismo , Línea Celular Tumoral , Daunorrubicina/química , Daunorrubicina/farmacología , Doxorrubicina/química , Espectroscopía de Resonancia por Spin del Electrón , Epirrubicina/química , Radicales Libres/metabolismo , Humanos , FN-kappa B/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Three new layered metal-organic frameworks (MOFs) based on 2-phenylsuccinic acid (H2psa) and lanthanide ions with the formula [Ln2(C10H8O4)3(H2O)] (Ln = Eu, Sm and Eu-Gd) have been synthesized under solvothermal conditions and fully characterized by single-crystal X-ray diffraction, thermal and vibrational analyses. The compounds are isostructural featuring 2D frameworks that consist of infinite zigzag chains composed of [LnO8] and [LnO8(H2O)] edge-sharing polyhedra linked by psa ligands leading to layers further connected by weak π-π interactions in an edge orientation. Moreover, a topological study was carried out to obtain the simplified net for better comparison with structurally related compounds. The crystals were exfoliated into nanolayers after miniaturization by addition of sodium acetate as a capping agent in the reaction medium. Scanning electron microscopy was applied to characterize the miniaturized samples whereas the exfoliated hybrid nanosheets were studied by atomic force microscopy. The photoluminescence (PL) properties of the bulk compounds as well as the miniaturized and exfoliated materials were investigated and compared with other related ones. An exhaustive study of the Eu(iii)-based MOFs was performed on the basis of the obtained PL parameters (excitation and emission spectra, kr, knr, intrinsic quantum yields and lifetimes) to explore the underlying structure-property relationships.
Asunto(s)
Elementos de la Serie de los Lantanoides/química , Luminiscencia , Succinatos/química , Cristalografía por Rayos XRESUMEN
The impact of ionizing radiation generated by a beam of electrons of 25-400 kGy on the stability of such analogs of anthracycline antibiotics as daunorubicin (DAU), doxorubicin (DOX), and epidoxorubicin (EPI) was studied. Based on EPR results, it was established that unstable free radicals decay exponentially with the half-time of 4 days in DAU and DOX and 7 days in EPI after irradiation. Radiation-induced structural changes were analyzed with the use of spectrophotometric methods (UV-Vis and IR) and electron microscope imaging (SEM). A chromatographic method (HPLC-DAD) was applied to assess changes in the contents of the analogs in the presence of their impurities. The study showed that the structures of the analogs did not demonstrate any significant alterations at the end of the period necessary for the elimination of unstable free radicals. The separation of main substances and related substances (impurities and potential degradation products) allowed determining that no statistically significant changes in the content of particular active substances occurred and that their conversion due to the presence of free radicals resulting from exposure to an irradiation of 25 kGy (prescribed to ensure sterility) was not observed.
Asunto(s)
Antraciclinas/química , Antibacterianos/química , Radiación Ionizante , Esterilización/métodos , SemividaAsunto(s)
Doxorrubicina/farmacología , Inflamación/inducido químicamente , Inflamación/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Transducción de Señal/fisiología , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Doxorrubicina/administración & dosificación , Inyecciones Intraperitoneales , Ratones , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Transducción de Señal/genética , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Decades of research have indicated that gap junction channels contribute to the propagation of apoptosis between neighboring cells. Inositol 1,4,5-trisphosphate (IP3) has been proposed as the responsible molecule conveying the apoptotic message, although conclusive results are still missing. We investigated the role of IP3 in a model of gap junction-mediated spreading of cytochrome C-induced apoptosis. We used targeted loading of high-molecular-weight agents interfering with the IP3 signaling cascade in the apoptosis trigger zone and cell death communication zone of C6-glioma cells heterologously expressing connexin (Cx)43 or Cx26. Blocking IP3 receptors or stimulating IP3 degradation both diminished the propagation of apoptosis. Apoptosis spread was also reduced in cells expressing mutant Cx26, which forms gap junctions with an impaired IP3 permeability. However, IP3 by itself was not able to induce cell death, but only potentiated cell death propagation when the apoptosis trigger was applied. We conclude that IP3 is a key necessary messenger for communicating apoptotic cell death via gap junctions, but needs to team up with other factors to become a fully pro-apoptotic messenger.
Asunto(s)
Apoptosis , Uniones Comunicantes/metabolismo , Inositol 1,4,5-Trifosfato/metabolismo , Animales , Comunicación Celular , Permeabilidad de la Membrana Celular , Conexina 26 , Conexina 43/metabolismo , Conexinas/genética , Conexinas/metabolismo , Citocromos c/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Ratas , Transducción de SeñalRESUMEN
Anthracycline antibiotics are inducers of an immunogenic form of apoptosis that has immunostimulatory properties because of the release of damage-associated molecular patterns. To study the mechanisms used by the innate immune system to sense this immunogenic form of cell death, we established an in vivo model of cell death induced by intraperitoneal injection of doxorubicin, a prototype of anthracyclines. The acute sterile inflammation in this model is characterized by rapid influx of neutrophils and increased levels of IL-6 and monocyte chemotactic protein-1. We demonstrate that acute inflammation induced by doxorubicin is associated with apoptosis of monocytes/macrophages and that it is specific for doxorubicin, an immunogenic chemotherapeutic. Further, the inflammatory response is significantly reduced in mice deficient in myeloid differentiation primary response gene 88 (MyD88), TLR-2 or TLR-9. Importantly, a TLR-9 antagonist reduces the recruitment of neutrophils induced by doxorubicin. By contrast, the acute inflammatory response is not affected in TRIF(Lps2) mutant mice and in TLR-3, TLR-4 and caspase-1 knockout mice, which shows that the inflammasome does not have a major role in doxorubicin-induced acute inflammation. Our findings provide important new insights into how the innate immune system senses immunogenic apoptotic cells and clearly demonstrate that the TLR-2/TLR-9-MyD88 signaling pathways have a central role in initiating the acute inflammatory response to this immunogenic form of apoptosis.
Asunto(s)
Apoptosis/inmunología , Doxorrubicina/farmacología , Inflamación/inducido químicamente , Inflamación/inmunología , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 9/inmunología , Animales , Antibióticos Antineoplásicos/farmacología , Caspasa 1/genética , Caspasa 1/inmunología , Femenino , Macrófagos/citología , Macrófagos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Monocitos/citología , Monocitos/inmunología , Factor 88 de Diferenciación Mieloide/genética , Factor 88 de Diferenciación Mieloide/inmunología , Transducción de Señal/inmunología , Receptor Toll-Like 2/genética , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/inmunología , Receptor Toll-Like 9/antagonistas & inhibidores , Receptor Toll-Like 9/genéticaRESUMEN
The potato cyst nematodes (PCN) G. rostochiensis (Woll.) and G. pallida (Stone) are the most economically important pests of potato (Solanum tuberosum L.) in the UK and are widespread in ware potato growing regions in Europe. The new EU directive 2007/33/EC which came into effect July 1, 2010 aims to control their spread and limit further increases in populations. We are investigating the role of temperature in the life cycle of PCN to assess how this effects population multiplication in relation to managing PCN. Hatching and nematode development are stages in the life cycle that are affected by temperature and thus are important life stages that can be examined to determine the impact of temperature on the length of time required for one generation to be completed and the potential for final populations to increase on different potato genetic backgrounds. In some conditions a partial or complete second generation has also been observed within the growing season. Females have been observed on the surface of tubers and "pecking" skin damage can occur which may be a result of a second generation. We are investigating the influence of temperature on the potential for a second generation or the induction of diapause.
Asunto(s)
Enfermedades de las Plantas/parasitología , Solanum tuberosum/parasitología , Tylenchoidea/crecimiento & desarrollo , Animales , Femenino , Estadios del Ciclo de Vida , Masculino , TemperaturaRESUMEN
BAC (bacterial artificial chromosome) clones from the genomic BAC library of the narrow-leafed lupin (Lupinus angustifolius) were used for cytogenetic mapping of mitotic metaphase chromosomes of that species by the BAC-FISH technique. Location of the clones, together with cytogenetic markers localised earlier by FISH (fluorescence in situ hybridisation) and PRINS (primed in situ DNA labelling), was combined with computer-aided chromosome measurements, to construct the first idiogram of the narrow-leafed lupin. The chromosomes are meta- or submetacentric; the mean absolute chromosome lengths range from 1.9 microm to 3.8 microm, and mean relative lengths from 1.6% to 3.3%. Data concerning linkage of resistance to 2 fungal pathogens as well as assignment of the second linkage group to the appropriate chromosome are given for the first time.
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Cromosomas de las Plantas/genética , Hibridación Fluorescente in Situ , Cariotipificación , Lupinus/genética , Cromosomas Artificiales Bacterianos/genética , ADN de Plantas , Genoma de Planta , Lupinus/clasificación , Hojas de la Planta , Etiquetado in Situ PrimedRESUMEN
The results of computations of spectroscopic parameters of lowest-lying electronic excited states of azobenezene derivatives are presented. The analysis of experimentally recorded spectra was supported by quantum chemical calculations using density functional theory. The theoretically determined resonant (two-photon absorption probabilities) and non-resonant (first-order hyperpolarisability) nonlinear optical properties are also discussed, with an eye towards the performance of recently proposed long-range corrected (LRC) schemes (LC-BLYP and CAM-B3LYP functionals).
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Compuestos Azo/química , Modelos Moleculares , Espectrofotometría/métodos , Algoritmos , Simulación por Computador , Modelos Químicos , Estructura Molecular , Teoría CuánticaRESUMEN
BACKGROUND: Mild anaemia frequently occurs in patients with chronic heart failure (CHF), particularly in the advanced stages of the disease. The correction of anaemia with erythropoietin is a therapeutic possibility. The aim of this study was to assess prospectively the relationship between the prevalence of anaemia (haemoglobin level
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Anemia/etiología , Insuficiencia Cardíaca/complicaciones , Análisis de Varianza , Anemia/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Estadísticas no ParamétricasRESUMEN
Sensitivity to antibiotics of the most common pathogens isolated from the upper airways in north-west part of Poland shown significant regional variation. The rise in resistance to penicillin for Streptococcus pneumoniae (to 22%) and to macrolides for Streptococcus pyogenes, Streptococcus pneumoniae and Staphylococcus aureus was observed. No differences in sensitivity have been found between pathogens isolated from hospital and ambulatory patients.
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Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Penicilinas/uso terapéutico , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Infecciones del Sistema Respiratorio/microbiología , Infecciones Bacterianas/epidemiología , Áreas de Influencia de Salud , Humanos , Macrólidos , Pruebas de Sensibilidad Microbiana , Polonia/epidemiología , Infecciones del Sistema Respiratorio/epidemiologíaAsunto(s)
Vacunas contra el Cáncer/uso terapéutico , Interleucina-6/metabolismo , Melanoma/terapia , Receptores de Interleucina-6/biosíntesis , Adulto , Anticuerpos Antineoplásicos/biosíntesis , Antígenos de Neoplasias/genética , Autoantígenos/genética , Vacunas contra el Cáncer/genética , Vacunas contra el Cáncer/inmunología , Femenino , Humanos , Interleucina-6/genética , Isoantígenos/genética , Masculino , Melanoma/genética , Melanoma/inmunología , Antígenos Específicos del Melanoma , Persona de Mediana Edad , Monofenol Monooxigenasa/genética , Proteínas de Neoplasias/genética , Pronóstico , Receptores de Interleucina-6/genética , SolubilidadRESUMEN
Since melanoma is a model immunogenic malignancy incurable in the disseminated phase of its natural course different immunotherapeutic approaches are tested in clinical trials. A number of tumour vaccines genetically modified (GMTV), with various immunostimulatory factors, are tested in phase I/II clinical trials. These factors include cytokines, tumour antigens (TA), costimulatory molecules or HLA antigens. We have designed a novel, mixed auto/allogeneic cellular melanoma vaccine modified with the IL-6 and the sIL-6R genes. Preclinical studies in a mouse model demonstrated that the IL-6/sIL-6R based vaccine is able to elicit efficient anti-tumour responses, mediated by CD8+ and NK cells, which resulted in inhibition of the tumour growth, metastases formation and prolonged survival of the animals treated. Irradiation of vaccine cells does not only lead to their sterilisation but also causes increased secretion of exogenous IL-6 and sIL-6R. Since January 1996 we have vaccinated more than one hundred metastatic melanoma patients. Promising clinical results (22% CR+PR, 32% SD) and the evidence of immune responses in the vaccinated patients have prompted us to design a phase III clinical trial which is to be open in 2000.
Asunto(s)
Vacunas contra el Cáncer/uso terapéutico , Ensayos Clínicos como Asunto , Ingeniería Genética , Inmunoterapia Activa , Melanoma/terapia , Vacunas Sintéticas/uso terapéutico , Animales , Vacunas contra el Cáncer/genética , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/efectos de la radiación , Modelos Animales de Enfermedad , Humanos , Inmunoterapia Activa/métodos , Interleucina-6/genética , Interleucina-6/inmunología , Melanoma/inmunología , Receptores de Interleucina-6/genética , Receptores de Interleucina-6/inmunología , Solubilidad , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/efectos de la radiaciónRESUMEN
The role of mandibular dysfunction in the etiology of headache is still underestimated in the medical literature. For this reason an analysis of own questionnaire investigations published in the years 1983 to 1999 was done. These investigations were carried out in 3915 subjects aged 15-66. In order to determine the prevalence of headache associated with mandibular dysfunction in the analysis mandibular parafunctions and clicking in the temporomandibular joints (TMJs) were selected. The comparison of the prevalence of headache in groups with and without mandibular parafunctions and in groups with and without clicking in the TMJs has shown that the prevalence of headache was significantly higher in groups with mandibular parafunctions and with clicking in the TMJs than in groups without these disturbances. The difference in the prevalence of headache in the investigated groups has shown that headaches noted in the population can be associated with mandibular parafunctions in 18.2% and dependent on the age with clicking in the TMJs in 9.7% to 25%.