649 research outputs found
The challenge to verify ceramide's role of apoptosis induction in human cardiomyocytes - a pilot study
<p>Abstract</p> <p>Background</p> <p>Cardioplegia and reperfusion of the myocardium may be associated with cardiomyocyte apoptosis and subsequent myocardial injury. In order to establish a pharmacological strategy for the prevention of these events, this study aimed to verify the reliability of our human cardiac model and to evaluate the pro-apoptotic properties of the sphingolipid second messenger ceramide and the anti-apoptotic properties of the acid sphingomyelinase inhibitor amitryptiline during simulated cardioplegia and reperfusion ex vivo.</p> <p>Methods</p> <p>Cardiac biopsies were retrieved from the right auricle of patients undergoing elective CABG before induction of cardiopulmonary bypass. Biopsies were exposed to <it>ex vivo </it>conditions of varying periods of cp/rep (30/10, 60/20, 120/40 min). Groups: I (untreated control, n = 10), II (treated control cp/rep, n = 10), III (cp/rep + ceramide, n = 10), IV (cp/rep + amitryptiline, n = 10) and V (cp/rep + ceramide + amitryptiline, n = 10). For detection of apoptosis anti-activated-caspase-3 and PARP-1 cleavage immunostaining were employed.</p> <p>Results</p> <p>In group I the percentage of apoptotic cardiomyocytes was significantly (p < 0.05) low if compared to group II revealing a time-dependent increase. In group III ceramid increased and in group IV amitryptiline inhibited apoptosis significantly (p < 0.05). In contrast in group V, under the influence of ceramide and amitryptiline the induction of apoptosis was partially suppressed.</p> <p>Conclusion</p> <p>Ceramid induces and amitryptiline suppresses apoptosis significantly in our ex vivo setting. This finding warrants further studies aiming to evaluate potential beneficial effects of selective inhibition of apoptosis inducing mediators on the suppression of ischemia/reperfusion injury in clinical settings.</p
Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks
Cataloged from PDF version of article.A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies
Anhydrous proton conducting poly(vinyl alcohol) (PVA)/ poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS)/1,2,4-triazole composite membrane
The design and fabrication of anhydrous proton exchange membranes are critically important for high temperature proton exchange membrane fuel cell (HT-PEMFC) operating between 100 and 200 °C. Herein, we demonstrate a novel proton conducting membrane consisting of poly(vinyl alcohol) (PVA), poly (2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) and 1,2,4-triazole, which was fabricated by physical blending, casting and solvent evaporation techniques. The in-situ chemical cross-linking was performed by glutaraldehyde (GA) to improve the water management of the membranes. The molecular structure of the membranes and intermolecular interactions between the constituents were confirmed by Fourier-transform infrared spectroscopy (FT-IR). The surface and cross-section morphologies of the membranes were observed by scanning electron microscopy (SEM). The thermal stability performance of the membranes was studied with thermogravimetric analysis (TGA). In order to determine the physico-chemical properties of the membranes, water uptake (WU), dimensional change and ion exchange capacity (IEC) tests were carried out. The proton conductivities of composite membranes increase with the temperature and the temperature dependencies exhibit an Arrhenius behavior. Proton conductivity measurements revealed an optimum ratio between PAMPS and 1,2,4-triazole content to achieve higher proton conductivity. In anhydrous state at 150 °C, the highest proton conductivity measured was 0.002 S/cm for PVA:PAMPS:1,2,4-triazole (1:1:1) composition. Overall, our investigation showed that 1,2,4-triazole is a promising proton carrier reagent above 100 °C when it is embedded into appropriate host polymers
Lateral migration of flexible fibers in Poiseuille flow between two parallel planar solid walls
Characterization of Annona cherimola mill. Seed oil from Madeira Island: a possible biodiesel feedstock
The possibility of using Annona seed oil as an
added value product, namely as a source of biodiesel, is
explored. Milled Annona seeds were extracted with hexane
at room temperature (72 h) and at solvent boiling point
(6 h). Oil content was found to be 25 and 22.4% respec tively. The oil was characterized in terms of lipid compo sition (HPLC–APCI–MS and 13C NMR), resistance to
oxidation and acidity index. FAME composition was
determined by GC–MS and five major peaks were identi fied. Production of biodiesel from Annona’s seed oil was
achieved by base-catalyzed transesterification. Density,
viscosity, refraction coefficient, acid value, cold filter
plugging point, cloud point and oxidation stability were
measured. The iodine value and the ‘‘apparent cetane
number’’ were calculated. Density, viscosity, acid value,
iodine value, cold filter plugging point and cloud point
were within EN14214 specifications and the calculated
‘‘apparent cetane number’’ was also indicative of a suitable
product.info:eu-repo/semantics/publishedVersio
With a Little Help from My Friends: Peer Coaching for Refugee Adolescents and the Role of Social Media
This intervention study investigated how much impact a specific peer-coaching (Peer2Peer) for refugee adolescents has on different factors of well-being for both sides: refugee adolescents (peers, N = 16) and their local peer coaches (buddies, N = 16). Next to pre- and post-tests, four buddies reflected on the process via weekly media diaries. We found that higher peer-loneliness and lower self-esteem was reported for peers in the beginning but these differences disappeared. These results were confirmed by buddies’ media diaries: lang
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Towards a three-dimensional microfluidic liver platform for predicting drug efficacy and toxicity in humans
Although the process of drug development requires efficacy and toxicity testing in animals prior to human testing, animal models have limited ability to accurately predict human responses to xenobiotics and other insults. Societal pressures are also focusing on reduction of and, ultimately, replacement of animal testing. However, a variety of in vitro models, explored over the last decade, have not been powerful enough to replace animal models. New initiatives sponsored by several US federal agencies seek to address this problem by funding the development of physiologically relevant human organ models on microscopic chips. The eventual goal is to simulate a human-on-a-chip, by interconnecting the organ models, thereby replacing animal testing in drug discovery and development. As part of this initiative, we aim to build a three-dimensional human liver chip that mimics the acinus, the smallest functional unit of the liver, including its oxygen gradient. Our liver-on-a-chip platform will deliver a microfluidic three-dimensional co-culture environment with stable synthetic and enzymatic function for at least 4 weeks. Sentinel cells that contain fluorescent biosensors will be integrated into the chip to provide multiplexed, real-time readouts of key liver functions and pathology. We are also developing a database to manage experimental data and harness external information to interpret the multimodal data and create a predictive platform
Lattice Boltzmann simulations of soft matter systems
This article concerns numerical simulations of the dynamics of particles
immersed in a continuum solvent. As prototypical systems, we consider colloidal
dispersions of spherical particles and solutions of uncharged polymers. After a
brief explanation of the concept of hydrodynamic interactions, we give a
general overview over the various simulation methods that have been developed
to cope with the resulting computational problems. We then focus on the
approach we have developed, which couples a system of particles to a lattice
Boltzmann model representing the solvent degrees of freedom. The standard D3Q19
lattice Boltzmann model is derived and explained in depth, followed by a
detailed discussion of complementary methods for the coupling of solvent and
solute. Colloidal dispersions are best described in terms of extended particles
with appropriate boundary conditions at the surfaces, while particles with
internal degrees of freedom are easier to simulate as an arrangement of mass
points with frictional coupling to the solvent. In both cases, particular care
has been taken to simulate thermal fluctuations in a consistent way. The
usefulness of this methodology is illustrated by studies from our own research,
where the dynamics of colloidal and polymeric systems has been investigated in
both equilibrium and nonequilibrium situations.Comment: Review article, submitted to Advances in Polymer Science. 16 figures,
76 page
Assessing the perceptions of pharmacists working in Lebanese hospitals on the continuing education preferences
Background: Continuing education (CE) is an international tool that requires lifelong active participation in learning activities allowing the pharmacist to stay a major player among others. In 2014 the CE program was introduced to the pharmacists licensed in Lebanon as a mandatory requirement for re-licensure. In the absence of guidelines regarding the quality and quantity of CE programs, behavioral resistance to precipitate in the CE programs might be encountered among the pharmacists.
Objective: The objective of this study is to assess the perceptions of pharmacists working in Lebanese hospitals on the continuing education preferences. The advantage of this program is to collect information that would help the Order of Pharmacy in Lebanon to upgrade the CE program in a way that is more acceptable and convenient for the pharmacists.
Methods: A cross-sectional study was carried out in 2016, using a proportionate random sample of Lebanese hospital pharmacies from all governorates in Lebanon. A structured questionnaire was distributed to all hospital pharmacies in Lebanon. Descriptive statistics were calculated for all study variables. This includes the mean and standard deviation for continuous measures, counts and percentages for categorical variables
Results: A total of 107 (53.5%) participants completed the questionnaires. The majority of participants were from Beirut and Mount Lebanon. The percentage of participants working at private hospitals was (68.2%).The majority of participants who completed the questionnaire (86.2%) agreed that continuing education programs affects their way of practice and increases their knowledge. Their preferred CE types to be used in the future were the computer based ones (60.6%), interactive workshops (45.5%) and printed materials (44.9%). Their considerations for selecting the CE type is based on their interest in the topic (80.6%), the ease of access to print or online material (77.2%), or the convenience of being offered during an event (67.1%). Participants noted that barriers to attend live CEs were mainly work responsibilities (76%), travel distance (65.6%), family commitments (48.4%) and scheduling (40.6%).
Conclusions: Lebanese hospital pharmacists are highly committed to CE. They consider it a practical tool for career development and advancement
Multi-Particle Collision Dynamics -- a Particle-Based Mesoscale Simulation Approach to the Hydrodynamics of Complex Fluids
In this review, we describe and analyze a mesoscale simulation method for
fluid flow, which was introduced by Malevanets and Kapral in 1999, and is now
called multi-particle collision dynamics (MPC) or stochastic rotation dynamics
(SRD). The method consists of alternating streaming and collision steps in an
ensemble of point particles. The multi-particle collisions are performed by
grouping particles in collision cells, and mass, momentum, and energy are
locally conserved. This simulation technique captures both full hydrodynamic
interactions and thermal fluctuations. The first part of the review begins with
a description of several widely used MPC algorithms and then discusses
important features of the original SRD algorithm and frequently used
variations. Two complementary approaches for deriving the hydrodynamic
equations and evaluating the transport coefficients are reviewed. It is then
shown how MPC algorithms can be generalized to model non-ideal fluids, and
binary mixtures with a consolute point. The importance of angular-momentum
conservation for systems like phase-separated liquids with different
viscosities is discussed. The second part of the review describes a number of
recent applications of MPC algorithms to study colloid and polymer dynamics,
the behavior of vesicles and cells in hydrodynamic flows, and the dynamics of
viscoelastic fluids
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