2,890 research outputs found
On the Potential of the Excluded Volume and Auto-Correlation as Neuromorphometric Descriptors
This work investigates at what degree two neuromorphometric measurements,
namely the autocorrelation and the excluded volume of a neuronal cell can
influence the characterization and classification of such a type of cells.
While the autocorrelation function presents good potential for quantifying the
dendrite-dendrite connectivity of cells in mosaic tilings, the excluded volume,
i.e. the amount of the surround space which is geometrically not accessible to
an axon or dendrite, provides a complementary characterization of the cell
connectivity. The potential of such approaches is illustrated with respect to
real neuronal cells.Comment: 15 pages, 6 figure
Adsorption cooler design, modeling, and dynamics and performance analyses
This paper presents an adsorption cooler (AC) driven by the surplus heat of a solar
thermal domestic hot water system to provide cooling to residential buildings. A cylindrical
tube adsorber using granular silica gel as adsorbent and water as adsorbate is considered.
The AC is modelled using a two-dimensional distributed parameter model that was implemented
in previous adsorption heating and cooling studies. The performance coefficients of
the resultant thermally driven colling system are obtained for a broad range of working conditions.
The thermally driven AC has a coefficient of performance (COP) of 0.5 and a specific
cooling power (SCP) of 44 W.kg--1, considering condenser, evaporator, and regeneration temperatures
of 15 oC, 18 oC, and 70 oC, respectively. Moreover, results show that the AC can be
used for refrigeration purposes at temperatures as low as 2 oC, and that it can also operate
during hotter days under temperatures of 42 oC.This work was supported by the grant SFRH/BD/145124/2019 and the projects
UIDB/00481/2020 and UIDP/00481/2020 - FCT - Fundação para a Ciência e a Tecnologia;
and CENTRO-01-0145-FEDER-022083 - Centro Portugal Regional Operational Programme
(Centro2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional
Development Fund.
The present study was developed in the scope of the Smart Green Homes Project [POCI-01-
0247-FEDER- 007678], a co-promotion between Bosch Termotecnologia S.A. and the University of Aveiro. It is financed by Portugal 2020 under the Competitiveness and Internationalization
Operational Program, and by the European Regional Development Fund
Decay Modes of Intersecting Fluxbranes
Just as the single fluxbrane is quantum mechanically unstable to the
nucleation of a locally charged spherical brane, so intersecting fluxbranes are
unstable to various decay modes. Each individual element of the intersection
can decay via the nucleation of a spherical brane, but uncharged spheres can
also be nucleated in the region of intersection. For special values of the
fluxes, however, intersecting fluxbranes are supersymmetric, and so are
expected to be stable. We explicitly consider the instanton describing the
decay modes of the two--element intersection (an F5-brane in the string theory
context), and show that in dimensions greater than four the action for the
decay mode of the supersymmetric intersection diverges. This observation allows
us to show that stable intersecting fluxbranes should also exist in type 0A
string theory.Comment: 19 pages, 6 figures. References adde
Fractal spectra in generalized Fibonacci one-dimensional magnonic quasicrystals
AbstractIn this work we carry out a theoretical analysis of the spectra of magnons in quasiperiodic magnonic crystals arranged in accordance with generalized Fibonacci sequences in the exchange regime, by using a model based on a transfer-matrix method together random-phase approximation (RPA). The generalized Fibonacci sequences are characterized by an irrational parameter σ(p,q), which rules the physical properties of the system. We discussed the magnonic fractal spectra for first three generalizations, i.e., silver, bronze and nickel mean. By varying the generation number, we have found that the fragmentation process of allowed bands makes possible the emergence of new allowed magnonic bulk bands in spectra regions that were magnonic band gaps before, such as which occurs in doped semiconductor devices. This interesting property arises in one-dimensional magnonic quasicrystals fabricated in accordance to quasiperiodic sequences, without the need to introduce some deferent atomic layer or defect in the system. We also make a qualitative and quantitative investigations on these magnonic spectra by analyzing the distribution and magnitude of allowed bulk bands in function of the generalized Fibonacci number Fn and as well as how they scale as a function of the number of generations of the sequences, respectively
tt* Geometry and Closed String Tachyon Potential
We propose a closed string tachyon action including kinetic and potential
terms for non-supersymmetric orbifolds. The action is given in terms of
solutions to equations which captures the geometry of vacua of the
corresponding N=2 worldsheet theory. In certain cases the solutions are well
studied. In case of tachyons of , solutions to affine toda
equations determine the action. We study the particular case of in detail and find that the Tachyon action is determined in terms of a
solution to Painleve III equation.Comment: 10 page
First report of a norovirus outbreak associated with the variant Sydney 2012 in Portugal
Introduction: This study describes the investigation of a gastroenteritis outbreak in a group of students, associated with a dinner reunion in February 2013 in Porto, Portugal.
Methodology: An anonymous structured questionnaire was developed and sent to 34 students who attended the dinner reunion. Eighteen students completed the questionnaire and thirteen met the case definition (attack rate of 72%). Stools from two students were screened for norovirus by RT-PCR using primer pairs that target the highly conserved polymerase gene and the capsid gene.
Results: Norovirus genotyping confirmed the variant Sydney 2012 as the probable cause of the outbreak.
Conclusion: This is the first report of an outbreak associated with the new variant Sydney 2012 in Portugal.The study was supported by FEDER funds through Programa Operacional Factores de Competividade (COMPETE), by national funding through Fundação para a Ciência e a Tecnologia (FCT) (project PTDC/CVT/113218/2009), and by grant SFRH/BD/45407/2008, and by project Ovislab ICT-2013-05-004-5314 ID-64757
Particle Pair Production in Cosmological General Relativity
The Cosmological General Relativity (CGR) of Carmeli, a 5-dimensional (5-D)
theory of time, space and velocity, predicts the existence of an acceleration
a_0 = c / tau due to the expansion of the universe, where c is the speed of
light in vacuum, tau = 1 / h is the Hubble-Carmeli time constant, where h is
the Hubble constant at zero distance and no gravity.
The Carmeli force on a particle of mass m is F_c = m a_0, a fifth force in
nature.
In CGR, the effective mass density rho_eff = rho - rho_c, where rho is the
matter density and rho_c is the critical mass density which we identify with
the vacuum mass density rho_vac = -rho_c.
The fields resulting from the weak field solution of the Einstein field
equations in 5-D CGR and the Carmeli force are used to hypothesize the
production of a pair of particles.
The mass of each particle is found to be m = tau c^3 / 4 G, where G is
Newton's constant.
The vacuum mass density derived from the physics is rho_vac = -rho_c = -3 /
(8 pi G tau^2).
The cosmic microwave background (CMB) black body radiation at the temperature
T_o = 2.72548 K which fills that volume is found to have a relationship to the
ionization energy of the Hydrogen atom. Define the radiation energy
epsilon_gamma = (1 - g) m c^2 / N_gamma, where (1-g) is the fraction of the
initial energy m c^2 which converts to photons, g is a function of the baryon
density parameter Omega_b and N_gamma is the total number of photons in the CMB
radiation field. We make the connection with the ionization energy of the first
quantum level of the Hydrogen atom by the hypothesis epsilon_gamma = [(1 - g) m
c^2] / N_gamma = alpha^2 mu c^2 / 2, where alpha is the fine-structure constant
and mu = m_p f / (1 + f), where f= m_e / m_p with m_e the electron mass and m_p
the proton mass.Comment: 14 pages, 0 figures. The final publication is available at
springerlink.co
DNA vaccines against dengue virus based on the ns1 gene: The influence of different signal sequences on the protein expression and its correlation to the immune response elicited in mice
AbstractWe analyzed four DNA vaccines based on DENV-2 NS1: pcENS1, encoding the C-terminal from E protein plus the NS1 region; pcENS1ANC, similar to pcENS1 plus the N-terminal sequence from NS2a (ANC); pcTPANS1, coding the t-PA signal sequence fused to NS1; and pcTPANS1ANC, similar to pcTPANS1 plus the ANC sequence. The NS1 was detected in lysates and culture supernatants from pcTPANS1-, pcENS1- and pcENS1ANC-transfected cells and not in cells with pcTPANS1ANC. Only the pcENS1ANC leads the expression of NS1 in plasma membrane, confirming the importance of ANC sequence for targeting NS1 to cell surface. High levels of antibodies recognizing conformational epitopes of NS1 were induced in mice immunized with pcTPANS1 and pcENS1, while only few pcENS1ANC-inoculated animals presented detectable anti-NS1 IgG. Protection against DENV-2 was verified in pcTPANS1- and pcENS1-immunized mice, although the plasmid pcTPANS1 induced slight higher protective immunity. These plasmids seem to activate distinct patterns of the immune system
Near Infrared Raman Spectroscopy To Detect The Calcification Of The Annular Mitral Valve
Cardiac valves are subjected to high repetitive mechanical stresses, particularly at the hinge points of the cusps and leaflets d ue to the over 40 millions cardiac cycles per year. These delicate structures can suffer cumulative lesions, complicated by the deposition of calcium phosphate mineral, which may lead to clinically important disease. Near Infrared Raman Spectroscopy gives important information about biological tissues composition and it is being used for diagnosis of some pathologies. The aim of this work was to detect trough the use of the Raman Spectroscopy technique the mitral annular calcification. A Ti:saphire laser operating at the near infrared wavelength of 785 nm was used for the excitation of the valve samples and the Raman radiation was detected by an optical spectrometer with a CCD liquid nitrogen cooled detector. In all, ten samples of normal and pathologic tissues were studied. They were approximately squared with the lateral size of 5 mm. It was observed that the Raman spectrum of the calcified mitral valve showed different behavior, when compared to normal tissues. Results indicate that this technique could be used to detect the deposition of the calcium phosphate mineral over the mitral valve.5622PART 16266Christensen, G., Cardiovascular and renal effects of atrial natriuretic factor (1993) Scand J. Clin Lab Invest, 53, pp. 203-207Peters, N.S., Cardiac arrhythmogenesis and the gap junction (1995) J Mol Cell Cardiol., 27, pp. 37-40Hanlon, E.B., Prospect for "in vivo" Raman spectroscopy (2000) Phys. Med. Biol., 45, pp. R1-59Lucas, A., Development of an avian model for restenosis (1996) Atherosclerosis, 119, pp. 17-41Sathaiah, S., Silveira Jr., L., Pasqualucci, C.A., Zangaro, R.A., Chavantes, M.C., Mtt, P., Correlated diagnosis of atherosclerosis with non-invasive Raman spectroscopy and pathological techniques (1996) International Laser Congress, p. 72. , GreeceSathaiah, S., Pasqualucci, C.A., Mtt, P., Application of near Infrared Raman spectroscopy for less invasive diagnosis of atherosclerosis (1997) Proc. International Conference on Lasers, 97. , U.S.AManoharan, R., UV resonance Raman spectroscopy for detection of colon cancer (1995) Lasers in Life Sci., 6, pp. 217-249Boustany, N.N., Analysis of normal and diseased colon mucosa using ultraviolet resonance Raman spectroscopy (1996) Proceedings of SPIE, 2679, pp. 66-70. , Advances in Lasers and Light Spectroscopy to Diagnose Cancer and other Diseases III: Optical Biopsy, San Jose CAPilotto, S., Mtt, P., Silveira Jr., L., Balbin Villaverde, A., Zangaro, R.A., Analysis of near-infrared Raman Spectroscopy as a new technique for a transcutaneous non-invasive diagnosis of blood components (2001) Laser Med. Sci, 16, pp. 2-9Jianan, Y., Wilson, B.C., Suria, D., Concentration measurements of multiple analytes in human sera by near-infrared laser Raman spectroscopy (1999) Appl Opt, 38 (25), pp. 5491-5497Berger, A., Koo, T.W., Itzhan, I., Horowitz, G., Feld, M.S., Multicomponent blood analysis by near-infrared Raman spectroscopy (1999) Appl Opt, 38 (13), pp. 2916-2916Otero, E.U., Sathaiah, S., Silveira Jr., L., Pma, P., Cag, P., Raman spectroscopy for diagnosis of calcification in human heart valves (2004) Spectroscopy: An International Journal, 18 (1), pp. 75-84Stone, N., Near-infrared Raman Spectroscopy for classification of epithelial pre-cancers and cancers (2002) J. Raman Spectrosc, 33, pp. 564-57
A different type of acute myocarditis : A case report of acute autoimmune myocarditis mediated by anti-PD-1 T lymphocyte receptor (pembrolizumab)
Pembrolizumab is an immune check-point inhibitor (ICI), which acts by blocking the T lymphocyte PD-1 inhibitor receptor. It has been increasingly used in advanced or non-responsive tumours with promising results. However, acute myocarditis is an infrequent but potentially life-threatening autoimmune adverse effect related to ICIs. This case deals with a 69-year-old gentleman on second-line therapy with pembrolizumab for advanced non-small cell lung cancer. Three weeks after first dose, the patient was diagnosed with an autoimmune hepatitis, treated with decreasing corticoid dosage, followed by acute heart failure. On admission, his electrocardiogram (ECG) showed diffuse repolarization changes and a transthoracic echocardiography revealed severe left ventricle impairment (left ventricular ejection fraction 32%). High-sensitivity cardiac troponin was elevated and a coronary angiogram was performed showing non-significant obstructive disease. An autoimmune myocarditis was suspected, and high-dose intravenous corticoid, intravenous vasodilators, and loop diuretics were started with favourable response. Cardiac magnetic resonance (CMR) imaging, performed 2 weeks after clinical onset, revealed extracellular oedema in the anteroseptal-apical left ventricle segments. A new transthoracic echocardiography, performed after 3 months, showed preserved left ventricle ejection fraction. Finally, the patient was readmitted due to an autoimmune myasthenia-like syndrome. Acute autoimmune myocarditis related to ICIs is a challenging diagnosis and its incidence has been underestimated in early studies. Endomyocardial biopsy (EMB) is the gold standard test for its diagnosis. Nevertheless, a definite myocarditis diagnosis is possible without EMB when characteristic clinical syndrome, elevated myonecrosis markers, and electrocardiographic, echocardiographic, and CMR changes are present together
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