1,991 research outputs found
Competition between local potentials and attractive particle-particle interactions in superlattices
Naturally occuring or man-made systems displaying periodic spatial
modulations of their properties on a nanoscale constitute superlattices. Such
modulated structures are important both as prototypes of simple
nanotechnological devices and as particular examples of emerging spatial
inhomogeneity in interacting many-electron systems. Here we investigate the
effect different types of modulation of the system parameters have on the
ground-state energy and the charge-density distribution of the system. The
superlattices are described by the inhomogeneous attractive Hubbard model, and
the calculations are performed by density-functional and density-matrix
renormalization group techniques. We find that modulations in local electric
potentials are much more effective in shaping the system's properties than
modulations in the attractive on-site interaction. This is the same conclusions
we previously (Phys. Rev. B 71, 125130) obtained for repulsive interactions,
suggesting that it is not an artifact of a specific state, but a general
property of modulated structures.Comment: 8 pages, 2 figure
Management of Ocular Setariasis in Ponies with Local Ocular Ivermectin Injection
Equine ocular Setariasis is a vision threatening disease of equine, caused by Setaria spp. This clinical communication describes two equine ocular Setariasis cases which were successfully treated with a single dose of ocular Ivermectin injection. Two ponies were referred to the Ambulatory clinic, Faculty of Veterinary Medicine, Peradeniya, Sri Lanka with the complaint of observation of a moving worm inside the anterior chamber of the eye since few days. The cloudiness of the cornea has been gradually increasing since the day the owner observed the worm inside the eye. Upon the clinical examination, both ponies were normal except the signs related to the eye condition including extent lacrimation, and moderate, unilateral corneal opacity. On close examination of the affected eye, the swirling movements of white thread like worm swimming continuously in aqueous humor of anterior chamber of the eye was evident in both cases. The ponies were properly restrained. 0.05ml of 1% ivermectin was loaded in to a sterile 1cc syringe with a 29G needle and was double diluted with normal saline. While the pony’s head was held firm, the needle was inserted in to the anterior chamber of the eye and the drug was released slowly. Prophylactic eye ointment containing an antibiotic i.e. 3% Tetracycline Hydrochloride (Galentic®) ointment was prescribed to be applied in the eye twice daily. Within an hour after the ivermectin treatment, the movements of the worm became sluggish and the movements were restricted to the most ventral part of the anterior chamber. The worm which was in the anterior chamber died on the same day of treatment. But few days later, the dead worms had triggered an inflammatory reaction in the eye, thus the animals were treated with an ophthalmic preparation containing NSAID i.e. 0.5% Ketorolac Tromethamine (Ketrosan®) ophthalmic solution. The condition recovered without any impairments of the vision or damages to the eye. Treatment of ocular Setariasis is always being a challenge. There are reported cases of successful surgical and medical interventions for ocular Setariasis in equids. This method would provide a less invasive, quick method done using only a single dose of ocular ivermectin injection in order to treat equine ocular Setariasis
Probing singularities in quantum cosmology with curvature scalars
We provide further evidence that the canonical quantization of cosmological
models eliminates the classical Big Bang singularity, using the {\it
DeBroglie-Bohm} interpretation of quantum mechanics. The usual criterion for
absence of the Big Bang singularity in Friedmann-Robertson-Walker quantum
cosmological models is the non-vanishing of the expectation value of the scale
factor. We compute the `local expectation value' of the Ricci and Kretschmann
scalars, for some quantum FRW models. We show that they are finite for all
time. Since these scalars are elements of general scalar polynomials in the
metric and the Riemann tensor, this result indicates that, for the quantum
models treated here, the `local expectation value' of these general scalar
polynomials should be finite everywhere. Therefore, we have further evidence
that the quantization of the models treated here eliminates the classical Big
Bang singularity. PACS: 04.40.Nr, 04.60.Ds, 98.80.Qc.Comment: 9 pages, 6 figure
In vitro culture of Annona emarginata: a rootstock for commercial annonaceae species
Annona emarginata is a native fruit tree in the Brazilian Cerrado which, unlike the commercial species, does not present a high fruit quality. On the other hand, it stands out based on its rootstock value. However, there are some problems that hinder the largescale production of Annona emarginata seedlings for use as a rootstock. In order to overcome these difficulties, micropropagation has become a viable alternative for the rapid and efficient propagation of Annona spp, but Annona emarginata micropropagation has not yet been reported. Therefore, the aim of this study was to initiate Annona emarginata in vitro growth. For axillary shoot proliferation, in vitro nodal segments of 0.5 cm were transferred to MS or WPM supplemented with BA at different concentrations. Nodal segments were also cultured on WPM medium with ranging concentrations of different plant growth regulators, aiming for either shoot elongation or rooting. The results showed that the use of 1 µM BA in WPM medium is recommended for in vitro multiplication of Annona emarginata. This is based on the low adventitious shoot formation, combined with a higher number of buds and leaves. The use of GA3 at any concentration tested induced the formation of malformed plants. Root formation could not be stimulated, regardless the duration of auxin treatment
Laparoscopic antireflux surgery in patients with extra esophageal symptoms related to asthma
Asthma, laryngitis and chronic cough are atypical symptoms of the gastroesophageal reflux disease. To analyze the efficacy of laparoscopic surgery in the remission of extra-esophageal symptoms in patients with gastroesophageal reflux, related to asthma. Were reviewed the medical records of 400 patients with gastroesophageal reflux disease submitted to laparoscopic Nissen fundoplication from 1994 to 2006, and identified 30 patients with extra-esophageal symptoms related to asthma. The variables considered were: gender, age, gastroesophageal symptoms (heartburn, acid reflux and dysphagia), time of reflux disease, treatment with proton pump inhibitor, use of specific medications, treatment and evolution, number of attacks and degree of esophagitis. Data were subjected to statistical analysis, comparing the pre- and post-surgical findings. The comparative analysis before surgery (T1) and six months after surgery (T2) showed a significant reduction on heartburn and reflux symptoms. Apart from that, there was a significant difference between the patients with daily crises of asthma (T1 versus T2, 45.83% to 16.67%, p=0.0002) and continuous crises (T1, 41.67% versus T2, 8.33%, p=0.0002). Laparoscopic Nissen fundoplication was effective in improving symptoms that are typical of reflux disease and clinical manifestations of asthma.Asthma, laryngitis and chronic cough are atypical symptoms of the gastroesophageal reflux disease. To analyze the efficacy of laparoscopic surgery in the remission of extra-esophageal symptoms in patients with gastroesophageal reflux, related to asthma. W2729295sem informaçãosem informaçã
Development of β-TCP-Ti6Al4V structures: Driving cellular response by modulating physical and chemical properties
Acknowledgments
This work was supported by FCT (Fundação para a Ciência e Tecnologia) through the grants SFRH/BD/140191/2018; SFRH/BPD/112111/2015, SFRH/BD/128657/2017, SFRH/BD/141056/2018; SFRH/BPD/97701/2013, PD/BDE/127836/2016, and the projects PTDC/EMS-TEC/5422/2014_ADAPTPROSTHESIS and NORTE-01-
0145-FEDER-000018-HAMaBICo. Additionally, this work was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.Load-bearing implants success is strongly dependent on several physical and chemical properties that are known to drive cellular response. In this work, multi-material β-TCP-Ti6Al4V cellular structures were designed to combine Ti6Al4V mechanical properties and β-Tricalcium Phosphate bioactivity, in order to promote bone ingrowth as the bioactive material is being absorbed and replaced by newly formed bone. In this sense, the produced structures were characterized regarding roughness, wettability, β-TCP quantity and quality inside the structures after fabrication and the pH measured during cell culture (as consequence of β-TCP dissolution) and those aspects were correlated with cellular viability, distribution, morphology and proliferation. These structures displayed a hydrophilic behavior and results showed that the addition of β-TCP to these
cellular structures led to an alkalization of the medium, aspect that significantly influences the cellular response. Higher impregnation ratios were found more adequate for lowering the media pH and toxicity, and thus enhance cell adhesion and proliferation.info:eu-repo/semantics/publishedVersio
45S5 BAG-Ti6Al4V structures: The influence of the design on some of the physical and chemical interactions that drive cellular response
This work was supported by FCT (Fundação para a Ciência e Tecnologia) through the grants SFRH/BPD/112111/2015, SFRH/BD/128657/2017, PD/BDE/127836/2016, SFRH/BPD/97701/2013, SFRH/
BD/141056/2018, SFRH/BD/140191/2018 and the projects PTDC/EMSTEC/5422/2014 and NORTE-01-0145-FEDER-000018-HAMaBICo. Additionally, this work was supported by FCT with the reference project
UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.Multi-material Ti6Al4V cellular structures impregnated with 45S5 bioactive glass were designed and produced
using Selective LaserMelting (SLM), an additive manufacturing technique, combinedwith Press and Sintering focusing on load bearing components like hip implants. These structures were designed to combine Ti6Al4V mechanical properties and promote bone ingrowth into the structure as the bioactive material (45S5) is being
absorbed and replaced by newly formed bone. The influence of these structures design on some of the physical and chemical aspects that drive cellular response was assessed. Roughness, wettability, bioactive glass quantity and quality on the structures after processing and the pH measured during cell culture (as a consequence of bioactive glass dissolution) were evaluated and correlated with cellular viability, cellular distribution, morphology and proliferation on the surface and inside the structures.info:eu-repo/semantics/publishedVersio
ERP correlates of error processing during performance on the HalsteadCategory Test
The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and
apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are
common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT
are lacking. This paper demonstrates the use of amethodology inspired on Singular SpectrumAnalysis (SSA) applied
to EEG signals, to remove high amplitude ocular andmovement artifacts during performance on the test. This filtering
technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly,
the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After
signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified.
This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited
more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential
that coupling ERP informationwith behavioral performance data can bring to the specificity of theHCT in diagnosing
different types of impairment in frontal brain function.info:eu-repo/semantics/publishedVersio
Demonstrating the Feasibility of Line Intensity Mapping Using Mock Data of Galaxy Clustering from Simulations
Visbal & Loeb (2010) have shown that it is possible to measure the clustering
of galaxies by cross correlating the cumulative emission from two different
spectral lines which originate at the same redshift. Through this cross
correlation, one can study galaxies which are too faint to be individually
resolved. This technique, known as intensity mapping, is a promising probe of
the global properties of high redshift galaxies. Here, we test the feasibility
of such measurements with synthetic data generated from cosmological dark
matter simulations. We use a simple prescription for associating galaxies with
dark matter halos and create a realization of emitted radiation as a function
of angular position and wavelength over a patch of the sky. This is then used
to create synthetic data for two different hypothetical instruments, one aboard
the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and another
consisting of a pair of ground based radio telescopes designed to measure the
CO(1-0) and CO(2-1) emission lines. We find that the line cross power spectrum
can be measured accurately from the synthetic data with errors consistent with
the analytical prediction of Visbal & Loeb (2010). Removal of astronomical
backgrounds and masking bright line emission from foreground contaminating
galaxies do not prevent accurate cross power spectrum measurements.Comment: 12 pages, 6 figures, Submitted to JCA
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