Acceleration of Amphibian Forelimb Regeneration By Polypeptide Growth Factors

Growth factors are potentially important modulators of epimorphic regeneration. This study examined effects of intraperitoneal administration of selected growth factors on limb regeneration of adult newts, Notophthalmus viridescens. These agents stimulated regeneration, producing overlapping but nonidentical effects. Fibroblast growth factor-2 (FGF-2) and insulin-like growth factor I (IGF-I) stimulated bud emergence (8.3 ± 0.6 and 8.3 ± 0.7 days, respectively, vs 11.4 ± 1.1 days for controls). Progression to the cone stage was enhanced by both FGF-2 and transforming growth factor beta 5 ( TGF-~ 5) ; 14.6 ± 0.5 and 15.4 ± 0.4 days with FGF-2 and TGF-~5 , respectively, vs 16.5 ± 0.5 days in controls. Insulin accelerated attainment of the palette stage, 17.0 ± 0.7 days vs 19.0 ± 0.4 days for controls. No treatments affected attaining the digital stage; means between 22.4 and 23.4 days. Histological analysis revealed changes consistent with gross observations. In addition, regenerates from newts treated with FGF-2, TGF-~5. and insulin displayed signs of greater (or earlier) histogenesis than did control animals. These results are consistent with the notion that FGF-2, TGF-~5. and possibly lGF-I stimulate proliferation of blastema cells and that insulin, FGF-2, and TGF-~5 promote differentiation and histogenesis during forelimb regeneration. In conclusion, these results demonstrate that several polypeptide growth factors positively affect the progress of forelimb regeneration, that different growth factors influence the same or similar events of epimorphic regeneration, and that diverse growth factors have nonidentical effects on regeneration

Preparation and Characterizations of Chitosan/Citral Nanoemulsions and their Antimicrobial Activity

Background and Objective: The antimicrobial activity of essential oils has been long recognized, however, they easily evaporate and/or decompose during preparation, owing to direct exposure to heat, pressure and light. The current study deals with the formulation and characterization of bio-based oil in water nanoemulsions and their antimicrobial activity against plant pathogens.Material and Methods: Citral oil and low molecular weight chitosan were used for preparation of nanoemulsions in the presence of sodium tripolyphosphate. Nanoemulsions were prepared by adding dropwise citral at different ratios into an aqueous solution containing chitosan, sodium tripolyphosphate and surfactant with continuous stirring and then ultrasonication. The success of formulation was confirmed by dynamic light scattering and scanning electron microscopy techniques. Physical stability and viscosity were investigated in details. The antimicrobial activity was evaluated against Erwinia carotovora, Aspergillus niger and Rhizopus stolonifer. Results and Conclusion: The nanoemulsions had a polydispersity index ranged from 0.508 to 0.614 and particle size from 27 to 1283 nm. The highest antimicrobial activity was observed with F1 formulation (EC50 = 23, 278 and 221 mg L-1, against Erwinia carotovora, Aspergillus niger and Rhizopus stolonifer, respectively). Based on the antimicrobial activity, the prepared chitosan/citral nanoemulsions can be a cost-effective way to protect crops from microbial pathogens. Because such formulations contain bioactive products, the development of resistant pathogens can be delayed.Conflict of Interest: The authors declare no conflict of interest.

The Impact of Applying ISO Standards Systems on Improving the Quality of the Performance in Higher Educational Institutions in Egypt

Applying ISO 21001:2018 standard ensures that universities have a competitive advantage as well as the achievement of their objectives. This study aims to identify the impact of implementing ISO 21001: 2018 management systems standards on the performance quality of higher education institutions. The study investigates the reasons why private higher education institutions seek ISO standards certificates in general and the specifications of management systems for educational institutions in particular. The study applied a set of statistical testing methods on paired samples as well as independent samples to ensure quality assurance. The study also proposes the required prerequisites that should be considered. The study investigated a hypothesis stating that "there are no statistically significant differences before and after applying the ISO 21001:2018 management systems specification for educational institutions in improving the quality of performance in higher education institutions" which was rejected by conducting an experiment in Future University in Egypt and accepting the alternative hypothesis. The study confirmed the impact of quality which was previously investigated by prior research that has been discussed in this study. The study further presented the need to apply quality based on determined criteria which were not considered in prior studies. Moreover, the study proposed the impact of ISO standards in educational institutions in general and in Egypt in specific. This recommendation is proved by this study to enhance the quality level in educational institutions

Methylene tetrahydrofolate reductase, transforming growth factor-β1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis

AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-β1 (TGF-β1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-β1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population

Polimorfismos dos genes metilenotetrahidrofolato redutase, fator de crescimento transformador β1 e linfotoxina‐α e susceptibilidade à artrite reumatoide

ResumoAntecedentesA artrite reumatoide é uma doença autoimune amplamente prevalente com sugerida predisposição genética.ObjetivosDetectar o padrão de polimorfismo dos genes metilenotetrahidrofolato redutase (MTHFR C677T e A1298C), fator de crescimento transformador β1 (TGF‐β1 T869C) e linfotoxina‐α (LT‐α A252G) em pacientes com artrite reumatoide e correlacionar esses padrões com a atividade da doença e os níveis séricos de fator de necrose tumoral alfa (TNF‐α), fator ativador de linfócitos B (BAFF) e osteopontina.MétodosForam genotipados 194 indivíduos – 90 controles e 104 com artrite reumatoide – à procura de polimorfismos dos genes MTHFR C677T e A1298C, TGF‐β1 T869C e LT‐α A252G com uma metodologia baseada na PCR‐RFLP. Mensuraram‐se também os níveis séricos de TNF‐α, osteopontina e BAFF com kits de Elisa.ResultadosO genótipo CT e o alelo T do MTHFR C677T e o genótipo GG e alelo G do LT‐α A252G estão associados ao risco de AR e a níveis mais elevados da citocina pró‐inflamatória TNF‐α em pacientes com artrite reumatoide.ConclusãoOs achados do presente estudo sugerem que há associação entre os polimorfismos dos genes MTHFR C677T e LT‐α A252G e um risco aumentado de AR nessa amostra da população egípcia.AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677T and A1298C), transforming growth factor‐β1 (TGF‐β1 T869C) and lymphotoxin‐α (LT‐α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor‐alpha (TNF‐α), B‐Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677T and A1298C, TGF‐β1 T869C and LT‐α A252G polymorphisms using a methodology based on PCR‐RFLP. Also serum levels of TNF‐α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677T and GG genotype and G allele of LT‐α A252G are associated with the risk of RA and with higher levels of the pro‐inflammatory cytokine, TNF‐α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677T and LT‐α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population

Measuring the brightness temperature distribution of extragalactic radio sources with space VLBI

We have used VSOP space very long baseline interferometry observations to measure the brightness temperature distribution of a well-defined sub-set of the Pearson-Readhead sample of extragalactic radio sources. VLBI which is restricted to Earth-diameter baselines is not generally sensitive to emitting regions with brightness temperatures greater than approximately $10^{12}$ K, coincidentally close to theoretical estimates of brightness temperature limits, $10^{11} - 10^{12}$ K. We find that a significant proportion of our sample have brightness temperatures greater than $10^{12}$ K; many have unresolved components on the longest baselines, and some remain completely unresolved. These observations begin to bridge the gap between the extended jets seen with ground-based VLBI and the microarcsecond structures inferred from intraday variability, evidenced here by the discovery of a relationship between intraday variability and VSOP-measured brightness temperature, likely due to the effects of relativistic beaming. Also, lower limits on jet Lorentz factors, estimated from space VLBI observations, are starting to challenge numerical simulations that predict low Lorentz factor jets.Comment: 4 pages + 1 figure, ApJ letters, accepte

The Pearson-Readhead Survey of Compact Extragalactic Radio Sources From Space. II. Analysis of Source Properties

We have performed a multi-dimensional correlation analysis on the observed properties of a statistically complete core-selected sample of compact radio-loud active galactic nuclei, based on data from the VLBI Space Observing Programme (Paper I) and previously published studies. Our sample is drawn from the well-studied Pearson-Readhead (PR) survey, and is ideally suited for investigating the general effects of relativistic beaming in compact radio sources. In addition to confirming many previously known correlations, we have discovered several new trends that lend additional support to the beaming model. These trends suggest that the most highly beamed sources in core-selected samples tend to have a) high optical polarizations; b) large pc/kpc-scale jet misalignments; c) prominent VLBI core components; d) one-sided, core, or halo radio morphology on kiloparsec scales; e) narrow emission line equivalent widths; and f) a strong tendency for intraday variability at radio wavelengths. We have used higher resolution space and ground-based VLBI maps to confirm the bi-modality of the jet misalignment distribution for the PR survey, and find that the sources with aligned parsec- and kiloparsec-scale jets generally have arcsecond-scale radio emission on both sides of the core. The aligned sources also have broader emission line widths. We find evidence that the BL Lacertae objects in the PR survey are all highly beamed, and have very similar properties to the high-optically polarized quasars, with the exception of smaller redshifts. A cluster analysis on our data shows that after partialing out the effects of redshift, the luminosities of our sample objects in various wave bands are generally well-correlated with each other, but not with other source properties.Comment: 21 pages, 10 figures. Accepted for publication in the Astrophysical Journal. Part I can be found at astro-ph/010227

Discovery of the Galaxy Proximity Effect and Implications for Measurements of the Ionizing Background Radiation at Low Redshifts

We present an analysis of galaxy and QSO absorption line pairs toward 24 QSOs at redshifts between z~0.2 and 1 in an effort to establish the relationship between galaxies and absorption lines in physical proximity to QSOs. We demonstrate the existence of a galaxy proximity effect, in that galaxies in the vicinities of QSOs do not show the same incidence and extent of gaseous envelopes as galaxies far from QSOs. We show that the galaxy proximity effect exists to galaxy-QSO velocity separations of ~ 3000 km/s, much larger than the size of a typical cluster (~ 1000 km/s), i.e. it is more comparable to the scale of the sphere of influence of QSO ionizing radiation rather than the scale of galaxy-QSO clustering. This indicates that the QSO ionizing radiation rather than some dynamical effect from the cluster environment is responsible for the galaxy proximity effect. We combine previous findings that (1) many or most Lya absorption lines arise in extended galaxy envelopes, and (2) galaxies cluster around QSOs to show that the magnitude of the Lya forest proximity effect is underestimated. Consequently, determinations of the UV ionizing background intensity using the proximity effect are likely overestimated. We use the galaxy-QSO cross-correlation function measured from our data to estimate the magnitude of this overestimate and find that it could be as high as a factor of 20 at z<1. This can have strong implications for models of the origin and evolution of the ionizing background, and may indicate that QSOs produce sufficient ionizing flux at all redshifts to account for the entire background radiation field.Comment: 26 pages, 3 figures, to appear in ApJ, October 20, 200

Electrical transport between epitaxial manganites and carbon nanotubes

The possibility of performing spintronics at the molecular level may be realized in devices that combine fully spin polarized oxides such as manganites with carbon nanotubes. However, it is not clear whether electrical transport between such different material systems is viable. Here we show that the room temperature conductance of manganite-nanotube-manganite devices is only half the value recorded in similar palladium-nanotube-palladium devices. Interestingly, the former shows a pseudogap in the conductivity below the relatively high temperature of 200 K. Our results suggest the possibility of new spintronics heterostructures that exploit fully spin polarized sources and drains