261 research outputs found
An experimental study on adsorption characteristics of r134a and r404a onto silicagel adsorbents
The objective of this study is to evaluate adsorption
characteristics of R134a and R404a on commercially available
silica gel samples. A constant volume variable pressure method
at different adsorption temperatures ranging from 293 to 323 K
and for pressures up to 500 kPa is used in the experimental
measurements. Three different type of commercially available
silica gel samples were chosen as adsorbent. The isotherms
obtained from the experimental measurements were presented.
Adsorption parameters were evaluated from the isotherms in
order to obtain correlations in the form of the Dubinin-Astakhov
(DA) equation. The pressure and temperature dependence of the
isosteric enthalpies of adsorption is computed with the
evaluation of the measured data and the derived equations.
Further, the enthalpy of adsorption data were extracted, and
correlations are provided for adsorbent-adsorbate pairs obtained
from the combinations of the three different silica gel specimens
and two refrigerants.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers
Using photonic crystals for structural coloration of textiles
In this work, poly (styrene-methyl methacrylate-acrylic acid) P(St-MMA-AA) composite nanospheres were deposited on the woven cotton fabrics. The deposited photonic crystals on the fabrics were evaluated for coating efficiency and resistance, chemical analysis and color variation by optical and SEM microscopy, ATR-FTIR, diffuse reflectance spectroscopy and washing fastness. The photonic nanospheres show an average diameter of 280 nm and display a face centre cubic (FCC) with an average thickness of 10 µm.This work is supported by FEDER funding on the COMPETE program and by national funds through FCT-Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136 and UID/CTM/00264.info:eu-repo/semantics/acceptedVersio
Ordering ambiguity revisited via position dependent mass pseudo-momentum operators
Ordering ambiguity associated with the von Roos position dependent mass (PDM)
Hamiltonian is considered. An affine locally scaled first order differential
introduced, in Eq.(9), as a PDM-pseudo-momentum operator. Upon intertwining our
Hamiltonian, which is the sum of the square of this operator and the potential
function, with the von Roos d-dimensional PDM-Hamiltonian, we observed that the
so-called von Roos ambiguity parameters are strictly determined, but not
necessarily unique. Our new ambiguity parameters' setting is subjected to
Dutra's and Almeida's [11] reliability test and classified as good ordering.Comment: 10 pages, no figures, revised/expanded, mathematical presentations in
section 2 (Especially, the typological Errors in Eqs.(9)-(12))are now
corrected. To appear in the Int. J. Theor. Phy
Immigrant community integration in world cities
As a consequence of the accelerated globalization process, today major cities
all over the world are characterized by an increasing multiculturalism. The
integration of immigrant communities may be affected by social polarization and
spatial segregation. How are these dynamics evolving over time? To what extent
the different policies launched to tackle these problems are working? These are
critical questions traditionally addressed by studies based on surveys and
census data. Such sources are safe to avoid spurious biases, but the data
collection becomes an intensive and rather expensive work. Here, we conduct a
comprehensive study on immigrant integration in 53 world cities by introducing
an innovative approach: an analysis of the spatio-temporal communication
patterns of immigrant and local communities based on language detection in
Twitter and on novel metrics of spatial integration. We quantify the "Power of
Integration" of cities --their capacity to spatially integrate diverse
cultures-- and characterize the relations between different cultures when
acting as hosts or immigrants.Comment: 13 pages, 5 figures + Appendi
Modulation of γ-Secretase Reduces β-Amyloid Deposition in a Transgenic Mouse Model of Alzheimer's Disease
SummaryAlzheimer's disease (AD) is characterized pathologically by the abundance of senile plaques and neurofibrillary tangles in the brain. We synthesized over 1200 novel gamma-secretase modulator (GSM) compounds that reduced Aβ42 levels without inhibiting epsilon-site cleavage of APP and Notch, the generation of the APP and Notch intracellular domains, respectively. These compounds also reduced Aβ40 levels while concomitantly elevating levels of Aβ38 and Aβ37. Immobilization of a potent GSM onto an agarose matrix quantitatively recovered Pen-2 and to a lesser degree PS-1 NTFs from cellular extracts. Moreover, oral administration (once daily) of another potent GSM to Tg 2576 transgenic AD mice displayed dose-responsive lowering of plasma and brain Aβ42; chronic daily administration led to significant reductions in both diffuse and neuritic plaques. These effects were observed in the absence of Notch-related changes (e.g., intestinal proliferation of goblet cells), which are commonly associated with repeated exposure to functional gamma-secretase inhibitors (GSIs)
A General Approach for the Exact Solution of the Schrodinger Equation
The Schr\"{o}dinger equation is solved exactly for some well known
potentials. Solutions are obtained reducing the Schr\"{o}dinger equation into a
second order differential equation by using an appropriate coordinate
transformation. The Nikiforov-Uvarov method is used in the calculations to get
energy eigenvalues and the corresponding wave functions.Comment: 20 page
Risk Prediction Scores for Recurrence and Progression of Non-Muscle Invasive Bladder Cancer: An International Validation in Primary Tumours
Abstract
Objective: We aimed to determine the validity of two risk scores for patients with non-muscle invasive bladder cancer in
different European settings, in patients with primary tumours.
Methods: We included 1,892 patients with primary stage Ta or T1 non-muscle invasive bladder cancer who underwent a
transurethral resection in Spain (n = 973), the Netherlands (n = 639), or Denmark (n = 280). We evaluated recurrence-free
survival and progression-free survival according to the European Organisation for Research and Treatment of Cancer
(EORTC) and the Spanish Urological Club for Oncological Treatment (CUETO) risk scores for each patient and used the
concordance index (c-index) to indicate discriminative ability.
Results: The 3 cohorts were comparable according to age and sex, but patients from Denmark had a larger proportion of
patients with the high stage and grade at diagnosis (p,0.01). At least one recurrence occurred in 839 (44%) patients and
258 (14%) patients had a progression during a median follow-up of 74 months. Patients from Denmark had the highest 10-
year recurrence and progression rates (75% and 24%, respectively), whereas patients from Spain had the lowest rates (34%
and 10%, respectively). The EORTC and CUETO risk scores both predicted progression better than recurrence with c-indices
ranging from 0.72 to 0.82 while for recurrence, those ranged from 0.55 to 0.61.
Conclusion: The EORTC and CUETO risk scores can reasonably predict progression, while prediction of recurrence is more
difficult. New prognostic markers are needed to better predict recurrence of tumours in primary non-muscle invasive
bladder cancer patients.This research received funding from the European Community's Seventh Framework program FP7/2007-2011 under grant agreement 201663 (Uromol project, http://www.uromol.eu/
Plasma Brain-Derived Neurotrophic Factor Levels Predict the Clinical Outcome of Depression Treatment in a Naturalistic Study
Remission is the primary goal of treatment for major depressive disorder (MDD). However, some patients do not respond to treatment. The main purpose of this study was to determine whether brain-derived neurotrophic factor (BDNF) levels are correlated with treatment outcomes. In a naturalistic study, we assessed whether plasma BDNF levels were correlated with clinical outcomes by measuring plasma BDNF in patients with depressive syndrome (MADRS score ≥18), and subsequently comparing levels between the subgroup of patients who underwent remission (MADRS score ≤8) and the subgroup who were refractory to treatment (non-responders). Patients with depressive syndrome who underwent remission had significantly higher plasma BDNF levels (p<0.001), regardless of age or sex. We also found a significant negative correlation between MADRS scores and plasma BDNF levels within this group (ρ = –0.287, p = 0.003). In contrast, non-responders had significantly lower plasma BDNF levels (p = 0.029). Interestingly, plasma BDNF levels in the non-responder group were significantly higher than those in the remission group in the initial stage of depressive syndrome (p = 0.002). Our results show that plasma BDNF levels are associated with clinical outcomes during the treatment of depression. We suggest that plasma BDNF could potentially serve as a prognostic biomarker for depression, predicting clinical outcome
Intelligence, educational attainment, and brain structure in those at familial high-risk for schizophrenia or bipolar disorder
First-degree relatives of patients diagnosed with schizophrenia (SZ-FDRs) show similar patterns of brain abnormalities and cognitive alterations to patients, albeit with smaller effect sizes. First-degree relatives of patients diagnosed with bipolar disorder (BD-FDRs) show divergent patterns; on average, intracranial volume is larger compared to controls, and findings on cognitive alterations in BD-FDRs are inconsistent. Here, we performed a meta-analysis of global and regional brain measures (cortical and subcortical), current IQ, and educational attainment in 5,795 individuals (1,103 SZ-FDRs, 867 BD-FDRs, 2,190 controls, 942 schizophrenia patients, 693 bipolar patients) from 36 schizophrenia and/or bipolar disorder family cohorts, with standardized methods. Compared to controls, SZ-FDRs showed a pattern of widespread thinner cortex, while BD-FDRs had widespread larger cortical surface area. IQ was lower in SZ-FDRs (d = −0.42, p = 3 × 10−5), with weak evidence of IQ reductions among BD-FDRs (d = −0.23, p =.045). Both relative groups had similar educational attainment compared to controls. When adjusting for IQ or educational attainment, the group-effects on brain measures changed, albeit modestly. Changes were in the expected direction, with less pronounced brain abnormalities in SZ-FDRs and more pronounced effects in BD-FDRs. To conclude, SZ-FDRs and BD-FDRs show a differential pattern of structural brain abnormalities. In contrast, both had lower IQ scores and similar school achievements compared to controls. Given that brain differences between SZ-FDRs and BD-FDRs remain after adjusting for IQ or educational attainment, we suggest that differential brain developmental processes underlying predisposition for schizophrenia or bipolar disorder are likely independent of general cognitive impairment
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