Αρχειοθήκη ιστολογίου

Δευτέρα 6 Ιουνίου 2016

Probing vaccine antigens against bovine mastitis caused by Streptococcus uberis

S0264410X.gif

Publication date: Available online 6 June 2016
Source:Vaccine
Author(s): Rosa Collado, Antoni Prenafeta, Luis González-González, Josep Antoni Pérez-Pons, Marta Sitjà
Streptococcus uberis is a worldwide pathogen that causes intramammary infections in dairy cattle. Because virulence factors determining the pathogenicity of S. uberis have not been clearly identified so far, a commercial vaccine is not yet available. Different S. uberis strains have the ability to form biofilm in vitro, although the association of this kind of growth with the development of mastitis is unknown. The objective of this study was to evaluate the potential use as vaccine antigens of proteins from S. uberis biofilms, previously identified by proteomic and immunological analyses. The capability of eliciting a protective immune response by targeted candidates was assayed on a murine model. Sera from rabbits immunized with S. uberis biofilm preparations and a convalescent cow intra-mammary infected with S. uberis were probed against cell wall proteins from biofilm and planktonic cells previously separated by two-dimensional gel electrophoresis. Using rabbit immunized serum, two proteins were found to be up-regulated in biofilm cells as compared to planktonic cells; when serum from the convalescent cow was used, up to sixteen biofilm proteins were detected. From these proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-biphosphate aldolase (FBA), and elongation factor Ts (EFTs) were chosen to be tested as vaccine antigen candidates. For this purpose, different groups of mice were immunized with the three recombinant-expressed proteins (each one formulated separately in a vaccine), and thereafter intraperitoneally challenged with S. uberis. The three proteins induced specific IgG antibodies, but a significant reduction of mortality was only observed in the groups of mice vaccinated with FBA or EFTs. These results suggest that FBA and EFTs might be considered as strong antigenic candidates for a vaccine against S. uberis bovine mastitis. Moreover, this is the first study to indicate that also in S. uberis, GAPDH, FBA and EFTs, as proteins detected in both cytoplasm and cell wall fractions, can play a second function (moonlighting), the latter being particularly involved in the virulence of such a pathogen organism.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1ra4dCx
via IFTTT

IGF1R and c-met as therapeutic targets for colorectal cancer

Publication date: August 2016
Source:Biomedicine & Pharmacotherapy, Volume 82
Author(s): Hajar Shali, Majid Ahmadi, Hossein Samadi Kafil, Abbasali Dorosti, Mehdi Yousefi
The type 1 IGF receptor (IGF1R) and mesenchymal-epithelial transition (MET) are hetrodimeric and transmembrane receptor tyrosine kinases, which are frequently overexpressed by several tumor types, including colorectal cancer (CRC). These receptors bind to their specific ligands, insulin growth factors (IGFs) and hepatocyte growth factor (HGF), respectively, and promote signaling cascades which mediates many functions such as proliferation and protection against apoptosis, cell scattering, tumor cell motility, invasion and metastasis. In patients with metastatic colorectal cancer (mCRC), IGF1R and c-met expression confer resistance to cetuximab (monoclonal antibodies against EGFR). Therefore, the c-met and IGF1R are now an attractive novel target for anticancer therapy. In this review, we will describe correlation between two receptors and their activation effects in tumor cells, and finally introduce useful and available strategies for their targeting.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1X7kupN
via IFTTT

Role of β-Adrenoceptors and L-Type Ca 2+ -Channels in the Mechanism of Reperfusion-Induced Heart Injury

We studied the effects of β-adrenoceptor antagonists propranolol and nadolol and L-type Ca2+-channel blocker verapamil on cardiac reperfusion injury developed after 45-min coronary occlusion. The substances were injected intravenously 5 min before reperfusion. The results indicate that activation of β-adrenoceptors and opening of L-type Ca2+-channels promote the development of cardiac reperfusion injury, while blockage of β-adrenoceptors and/or L-type Ca2+-channels prevents reoxygenation-induced myocardial injury. Propranolol, nadolol, and verapamil can produce infraction-limiting effects after onset of ischemic heart injury.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1X6s1oG
via IFTTT

Anxiolytic, Psychostimulant, and Analgesic Effects of Various Volumes of Ethanol Solution in Different Concentrations, but in the Same Dose

We studied the effect of ethanol (dose 2 g/kg) in various concentrations (5, 13, and 40%) and different volumes (40, 15.5, and 5 ml/kg) on the level of anxiety, locomotor activity, and pain sensitivity in rats. Administration of 40 ml/kg water to animals was followed by a significant increase in the time spent in the open arms of the elevated plus maze. Administration of water in a volume of 5 or 15.5 ml/kg had little effect on the level of anxiety. The greater was the volume of intragastrically administered ethanol, the stronger was the anxiolytic effect. The psychostimulant and analgesic effects of ethanol were more pronounced after administration of medium volumes and intermediate concentrations of ethanol-containing solutions. Since administration of these solutions cannot produce maximum blood concentration of ethanol, we believe that the observed effects are mainly related to the direct effect of ethanol on the stomach tissue.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U3r1hC
via IFTTT

New Genetic Constructs for Generation of Stable Therapeutic Antibodies to Organophosphorus Toxins in Methylotrophic Yeasts Pichia Pastoris

We propose a new method of obtaining of stable Fab-fragments of antibodies in Pichia pastoris expression system. Recently, we obtained Fab-fragments of antibodies neutralizing organophosphorus toxins. However, high yield of the target products was not attained because of high level of proteolytic degradation. In the present study, we identified sites of proteolytic degradation in Fab-fragments and endogenous proteases performing degradation, which allowed obtaining optimized genetic constructs for expression of antibody heavy chains (IgGγ1) and kappa and lambda isotypes of light chains. Co-transformation of these vectors allowed obtaining Fab-fragments of antibodies to organophosphorus toxins without proteolytic degradation of the product.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U3qSuN
via IFTTT

Ketamine-Midazolam Anesthesia Induces Total Inhibition of Cortical Activity in the Brain of Newborn Rats

The effects of general anesthetics ketamine and midazolam, the drugs that cause neuroapoptosis at the early stages of CNS development, on electrical activity of the somatosensory cortex in newborn rats were studied using extracellular recording of local field potentials and action potentials of cortical neurons. Combined administration of ketamine (40 mg/kg) and midazolam (9 mg/kg) induced surgical coma and almost completely suppressed early oscillatory patterns and neuronal firing. These effects persisted over 3 h after injection of the anesthetics. We concluded that general anesthesia induced by combined administration of ketamine and midazolam profoundly suppressed cortical activity in newborn rats, which can trigger neuroapoptosis in the developing brain.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1X6sas8
via IFTTT

Peptidyl Aldehyde Specifically Interacts with Immunosubunit β1i Proteasome: In Vitro and In Vivo Effects

We studied the effect of β1i-specific peptidyl aldehyde IPSI-001 on proteasome from mammalian cells. In concentrations <1 μM, this agent effectively suppressed immunoproteasome, but only slightly reduced chymotrypsin-like activity of constitutive proteasome. Intraperitoneal administration of this inhibitor to C3H/He mice in a dose of 100 mg/kg induced no significant physiological or behavioral changes, which attested to its considerable therapeutic potential in the treatment of autoimmune neurodegenerative pathologies.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1X6soPW
via IFTTT

Studying the Effect of a Composition of the Cluster Core in High-Radiopacity Cluster Complexes of Rhenium on Their Acute Toxicity In Vivo

An in vivo study was performed to evaluate the dependence of acute toxicity of high-radiopacity and luminescent octahedral cluster complexes of rhenium after intravenous injection on a composition of the cluster core. Changes in mouse body weight, water and food consumption, degree of intoxication, and morphological changes in the visceral organs were studied after intravenous injection of the following cluster complexes with various internal ligands (S, Se, or Te): Na4[{Re 6Te 8 }(CN)6], Na4[{Re 6Se 8 }(CN)6], and Na4[{Re 6S 8 }(CN)6]. The Na4[{Re 6S 8 } (CN)6] cluster complex was shown to be the safest for animals.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1YazRxe
via IFTTT

Effects of Deep Cooling and Re-Warming on Ionotropic Glutamatergic Receptors In Vitro

We studied the effects of cooling to -10°C and re-warming to 37°C on slices of rat olfactory cortex. The amplitudes of action potential in the lateral olfactory tract and excitatory postsynaptic potential activated by AMPA recovered during slow cooling/re-warming (0.1°C/min), while during rapid cooling/re-warming (9°C/min), they surpassed the control values. NMDA receptor-dependent mechanism was blocked in both cooling/re-warming modes. Swelling of the brain slices was observed during re-warming, especially during rapid cooling/re-warming. Nerve fibers of the lateral olfactory tract and AMPA-related processes survived deep cooling/re-warming, while NMDA-related processes were irreversibly blocked.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t0EJsF
via IFTTT

Cell Composition of Central and Peripheral Lymphoid Organs of Wistar Rats Treated with a Biomedical Cell Product

We studied the effect of a biomedical cell product (bone marrow multipotent mesenchymal stromal cells and products secreted by these cells in conditioned medium) on subpopulation composition of lymphoid cells of central and peripheral lymphoid organs of Wistar rats under normal conditions. Changes in the subpopulation composition of lymphoid organs depended on the route of administration of biomedical cell product.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1YaA4An
via IFTTT

Histoenzymological Characteristics of Smooth Muscle Cells in Myocardial Vessels: A Comparative Study under Conditions of Increased Left or Right Ventricular Afterload

Histoenzymological methods were used to study metabolism of smooth muscle cells of intramural myocardial arteries during experimental aortic or pulmonary artery stenosis. Aortic stenosis was accompanied by changes in smooth muscles of the left ventricle manifested by deceleration of tricarboxylic acid cycle, inhibition of oxidation of free fatty acids and their metabolites, flux redistribution in the glycolytic cascade, and inhibition of shuttle systems and biosynthetic processes. Similar metabolic alterations were observed in vessels of the ventricular septum, but they were not revealed in vessels of the right ventricle (except glycolysis stimulation). Under conditions of pulmonary artery stenosis, histoenzymological alterations in vascular smooth muscle of both ventricles and ventricular septum were similar, which attested to acceleration of tricarboxylic acid cycle, stimulation of oxidation of the free fatty acids with their metabolites, acceleration of glycolysis, and activation of the shuttle systems and biosynthetic processes. Comparative analysis of histoenzymological alterations revealed substantial differences in the character of metabolic changes under conditions of increased left and right ventricular afterload, which can be caused by peculiarities in myocardial blood flow, severity of circulatory disorders, severity of hypoxia, and intensity of processes maintaining ionic homeostasis in vascular smooth muscles and transport across the histohematic barriers. The data attest to important metabolic role of glycolysis in vascular smooth muscles of the myocardium, especially under conditions of enhanced afterload of the right ventricle.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t0FeTk
via IFTTT

Study of Fibronectin Type III-Like Domains Role in Activation of gp130 Receptor

Chimeric gp130 receptors were produced to study the role of three fibronectin type III-like domains in activation of gp130 receptor machinery. The ligand-induced dimerization of gp130 was sufficient to trigger STAT3 signaling pathway. These findings can be used as the basis in designing novel therapeutic gp130 inhibitors.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1tcx3UI
via IFTTT

2D-Crystal-Based Functional Inks

The possibility to produce and process graphene, related 2D crystals, and heterostructures in the liquid phase makes them promising materials for an ever-growing class of applications as composite materials, sensors, in flexible optoelectronics, and energy storage and conversion. In particular, the ability to formulate functional inks with on-demand rheological and morphological properties, i.e., lateral size and thickness of the dispersed 2D crystals, is a step forward toward the development of industrial-scale, reliable, inexpensive printing/coating processes, a boost for the full exploitation of such nanomaterials. Here, the exfoliation strategies of graphite and other layered crystals are reviewed, along with the advances in the sorting of lateral size and thickness of the exfoliated sheets together with the formulation of functional inks and the current development of printing/coating processes of interest for the realization of 2D-crystal-based devices.

Thumbnail image of graphical abstract

An overview on the process chain of 2D crystals is provided from the exfoliation of layered bulk counterparts in liquid to yield nanosheets, with controlled lateral sizes and thicknesses, to ink formulation and their printing/coating processes on different substrates for the realization of printed devices.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1Umvucz
via IFTTT

Erratum to: Hierarchical modeling identifies novel lung cancer susceptibility variants in inflammation pathways among 10,140 cases and 11,012 controls



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/22Jv2Lv
via IFTTT

Mitteilungen der DSG 6/2016



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U9Xcxp
via IFTTT

Mitteilungen der DGN 6/2016



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1UCN130
via IFTTT

Mitteilungen der DGPPN 6/2016



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U9WyzP
via IFTTT

Assessing utility of exercise test in determining exercise prescription in adolescent and adult patients with repaired tetralogy of fallot

Abstract

Parameters from cardiopulmonary exercise test (CPET) are useful prognostic factors for patients with repaired tetralogy of fallot (TOF). Its application in exercise prescription remains unclear. This study sought to define its role. We made current exercise recommendations in repaired TOF patients according to European Society of Cardiology (ESC) guideline, which were based on ventricular function, pressure/volume load, pulmonary artery pressure, hypoxemia and arrhythmic burden both at rest and during exercise. CPET parameters (peak oxygen consumption, oxygen uptake efficiency plateau, and E/CO2 slope), along with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status, were used to calculate "score to exercise". 112 repaired TOF adolescent and adult aged 32.6 ± 10.8 (14.05- to 56.99-year-old, median 30.1) years received exercise recommendations by ESC guideline, which suggested high, moderate and low intensity sports for 45 (40.2 %), 45 (40.2 %), and 22 (19.6 %) patients, respectively. The optimal cut-off values were 67 and 77 % for peak VO2, 86 and 100 % for OUEP, 22 and 28 for E/CO2 slope to correlate to the exercise intensity recommendation. But, individual CPET parameter had low consistency (41–46 %) in making decisions of exercise intensity compared to ESC recommendations. Using the "score to exercise", the consistency rate could be increased to 74.1 %. With "score to exercise" recommended exercise intensity, follow-up result revealed no adverse event related to sports. Individual CPET parameter did not correlate well to the exercise recommendation from ESC. We proposed a scoring system, "score to exercise", which incorporates three CPET parameters with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status. Score to exercise is easy to be assessed and provides useful information for exercise recommendation in patients with repaired TOF.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U4dYwB
via IFTTT

Factors associated with postoperative requirement of renal replacement therapy following off-pump coronary bypass surgery

Abstract

Cardiopulmonary bypass usage provokes a systemic inflammatory response resulting in deterioration of renal function. However, risk factors for requiring renal replacement therapy (RRT) following off-pump coronary artery bypass graft surgery (CABG) have not yet been fully elucidated. We reviewed 718 consecutive patients undergoing elective off-pump CABG at our institution, excluding patients on chronic hemodialysis preoperatively. Sub-analysis of patients with preserved renal function, defined as a creatinine level below a cut-off value of 1.12 mg/dL (obtained by receiver operating characteristic curve), was also performed. Of the 718 patients, 41 (5.7 %) required RRT. There were 556 patients (77.4 %) with preserved renal function preoperatively, and 13 (2.4 %) of these required postoperative RRT. Multivariate analysis revealed that age (years) and preoperative serum creatinine (mg/dL) and brain natriuretic peptide (BNP) levels (pg/dL) were associated with RRT [odds ratios (OR) 1.052, 95 % confidence interval (CI) 9.064 and 1.001, respectively, all p < 0.05] in the total population, whereas low albumin concentration was the only independent predictor for RRT in patients with preserved renal function (OR 0.062, p < 0.0001). When creatinine levels were below 1.5 mg/dL, the predictive power of hypoalbuminemia for RRT requirement overwhelmed that of creatinine or BNP levels. Older age, preoperative elevated creatinine and BNP levels were associated with a requirement for RRT following off-pump CABG. In patients with preserved renal function, hypoalbuminemia was most significantly related to the RRT requirement.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U9WHmP
via IFTTT

Flexible Electronics: An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

The design of an ultrathin, conformal electronic device that integrates electrotactile stimulation with electromyography, temperature, and strain sensing in a single, simple platform is reported by J. A. Rogers and co-workers on page 4462. Demonstrated application possibilities include prosthetic control with sensory feedback, monitors, and stimulation signals related to lower back exertion, and electrical muscle stimulation with feedback control.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1YbkBA7
via IFTTT

Carbon Nanotubes: Printed Carbon Nanotube Electronics and Sensor Systems (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

Printed electronics and sensors enable new applications ranging from low-cost disposable analytical devices to large-area sensor networks. Recent progress in printed carbon nanotube electronics in terms of materials, processing, devices, and applications is discussed on page 4397 by A. Javey and co-workers. The research challenges and opportunities regarding the processing and system-level integration are also discussed for enabling of practical applications.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PeCwyx
via IFTTT

Silk Fibroin: Silk Fibroin for Flexible Electronic Devices (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

Flexible electronic devices are necessary for applications involving unconventional interfaces, such as soft and curved biological systems, in which traditional silicon-based electronics confront a mechanical mismatch. Silk offers exquisite mechanical, optical, and electrical properties that are advantageous toward the development of next-generation biocompatible electronic devices. On page 4250, X. Chen and co-workers summarize the recent progress in the design and integration of silk-based flexible electronic devices where the silk materials can serve not only as passive but also as active components.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1Ybl3hC
via IFTTT

Electroluminescent Devices: Extremely Stretchable Electroluminescent Devices with Ionic Conductors (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

An extremely stretchable electroluminescent device is fabricated by P. S. Lee and co-workers, as described on page 4490. The stretchable alternating-current electroluminescent (ACEL) device possesses extremely high stretchability, and can be linearly stretched to 700% with the luminance being maintained at 70% of the initial value before stretching. The device can be repeatedly stretched to 400% with stable emission behavior. The presented device will provide new opportunities in stretchable lighting, volumetric 3D displays, interactive readout systems, and other unprecedented applications.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PeCRBs
via IFTTT

Deformable Electronics: Conducting Polymer Dough for Deformable Electronics (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

A simple strategy for changing a brittle conducting polymer (PEDOT:PSS) into a solution-processed highly deformable viscoelastic polymer is presented by H.-K. Baik, U. Jeong, and co-workers on page 4455. The storage modulus versus loss modulus of the polymer is adjusted to control the viscoelastic properties to fit the properties required in deformable electronics. Rapid self-healing of conductivity, custom-designed LEDs with complex micropatterns, and foldable stretchable LEDs are demonstrated.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1Ybkftb
via IFTTT

Biphasic Metal Films: Intrinsically Stretchable Biphasic (Solid–Liquid) Thin Metal Films (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

On page 4507, S. P. Lacour and co-workers present highly conductive and stretchable solid–liquid films that are formed by physical vapor deposition of gallium onto an alloying gold layer. The image shows patterns defined by lift-off on an elastomer membrane. The magnified view is a false-color scanning electron microscopy (SEM) image (×5000) of the surface of the films under 50% applied strain, showing the liquid Ga (blue–gray) flowing between the AuGa2/Ga clusters (gold).



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PeCwi1
via IFTTT

Flexible and Stretchable Devices



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1YbkhkP
via IFTTT

Contents: (Adv. Mater. 22/2016)



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PeD3Ap
via IFTTT

3D Printing: 3D Printing of Shape Memory Polymers for Flexible Electronic Devices (Adv. Mater. 22/2016)

Thumbnail image of graphical abstract

On page 4449, D. Cohn, S. Magdassi, and co-workers describe a general and facile method based on 3D printing of methacrylated macromonomers to fabricate shape-memory objects that can be used in flexible and responsive electrical circuits. Such responsive objects can be used in the fabrication of soft robotics, minimal invasive medical devices, sensors, and wearable electronics. The use of 3D printing overcomes the poor processing characteristics of thermosets and enables complex geometries that are not easily accessible by other techniques.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1YbkDIh
via IFTTT

Masthead: (Adv. Mater. 22/2016)



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PeCvKZ
via IFTTT

Multifunctional Nanoparticles Self-Assembled from Small Organic Building Blocks for Biomedicine

Supramolecular self-assembly shows significant potential to construct responsive materials. By tailoring the structural parameters of organic building blocks, nanosystems can be fabricated, whose performance in catalysis, energy storage and conversion, and biomedicine has been explored. Since small organic building blocks are structurally simple, easily modified, and reproducible, they are frequently employed in supramolecular self-assembly and materials science. The dynamic and adaptive nature of self-assembled nanoarchitectures affords an enhanced sensitivity to the changes in environmental conditions, favoring their applications in controllable drug release and bioimaging. Here, recent significant research advancements of small-organic-molecule self-assembled nanoarchitectures toward biomedical applications are highlighted. Functionalized assemblies, mainly including vesicles, nanoparticles, and micelles are categorized according to their topological morphologies and functions. These nanoarchitectures with different topologies possess distinguishing advantages in biological applications, well incarnating the structure–property relationship. By presenting some important discoveries, three domains of these nanoarchitectures in biomedical research are covered, including biosensors, bioimaging, and controlled release/therapy. The strategies regarding how to design and characterize organic assemblies to exhibit biomedical applications are also discussed. Up-to-date research developments in the field are provided and research challenges to be overcome in future studies are revealed.

Thumbnail image of graphical abstract

Nanoparticles self-assembled from small organic building blocks show a promising application potential for biomedical applications such as cancer theranostics. The dynamic property of rationally designed building blocks enables self-assembled nanoparticles with high performance in biosensors, bioimaging, and drug delivery.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1OaCXPn
via IFTTT

Hierarchical Manipulation of Block Copolymer Patterns on 3D Topographic Substrates: Beyond Graphoepitaxy

Thumbnail image of graphical abstract

Templates of complex nanopatterns in a form of hierarchically sequenced dots and stripes can be generated in block copolymer films on lithography-free 3D topographic substrates. The approach exploits thickness- and swelling-responsive morphological behavior of block copolymers, and demonstrates novel possibilities of topography-guided registration of nanopatterns due to periodic confinement and spontaneous orthogonal flow-fields.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t2a6CX
via IFTTT

Hydration and Thermal Expansion in Anatase Nanoparticles

Thumbnail image of graphical abstract

A tunable thermal expansion is reported in nanosized anatase by taking advantage of surface hydration. The coefficient of thermal expansion of 4 nm TiO2 along a-axis is negative with hydrated surface and is positive without hydrated surface. High-energy synchrotron X-ray pair distribution function analysis combining with ab initio calculations on the specific hydrated surface have been carried out to reveal the local structure distortion that is responsible for the unusual negative thermal expansion.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1OaCDQX
via IFTTT

Mechanical Isolation of Highly Stable Antimonene under Ambient Conditions

Thumbnail image of graphical abstract

Antimonene fabricated by mechanical exfoliation is highly stable under atmospheric conditions over periods of months and even immersed in water. Density functional theory confirms the experiments and predicts an electronic gap of ≈1 eV. These results highlight the use of antimonene for optoelectronics applications.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t2aEcb
via IFTTT

Band Engineering by Controlling vdW Epitaxy Growth Mode in 2D Gallium Chalcogenides

Thumbnail image of graphical abstract

Atomically thin quasi-2D GaSe flakes are synthesized via van-der-Waals (vdW) epitaxy on a polar Si (111) surface. The band gap is continuously tuned from its commonly accepted value at 620 down to 700 nm range, which was only attained previously by alloying Te into GaSe (GaSexTe1−x). This is accomplished by manipulating various vdW epitaxy kinetic factors, which allows us to choose between screw-dislocation driven and layer-by-layer growth, and design different morphologies with different material–substrate interaction (strain) energies.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1OaCNaZ
via IFTTT

Is near-infrared light neuroprotective?



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/213i7Tj
via IFTTT

A Systematic Review: Childhood Cancer Survivors and Gastrointestinal Cancer

alertIcon.gif

Publication date: Available online 6 June 2016
Source:Cancer Treatment Reviews
Author(s): Isabel Griffin, Purnima Madhivanan




from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t2a6D3
via IFTTT

Influence of sucrose and xylitol on an early Streptococcus mutans biofilm in a dental simulator

Publication date: Available online 6 June 2016
Source:Archives of Oral Biology
Author(s): K.M. Salli, S.D. Forssten, S.J. Lahtinen, A.C. Ouwehand
ObjectivesIn vitro methods to study dental biofilms are useful in finding ways to support a healthy microbial balance in the oral cavity. The effects of sucrose, xylitol, and their combination on three strains of Streptococcus mutans and one strain of Streptococcus sobrinus were studied using a dental simulator.MethodsA simulator was used to mimic the oral cavity environment. It provided a continuous-flow system using artificial saliva (AS), constant temperature, mixing, and hydroxyapatite (HA) surface in which the influence of xylitol was studied. The quantities of planktonic and adhered bacteria were measured by real-time qPCR.ResultsCompared against the untreated AS, adding 1% sucrose increased the bacterial colonization of HA (p<0.0001) whereas 2% xylitol decreased it (p<0.05), with the exception of clinical S. mutans isolate 117. The combination of xylitol and sucrose decreased the bacterial quantities within the AS and the colonization on the HA by clinical S. mutans isolate 2366 was reduced (p < 0.05). Increasing the concentration (2% − 5%) of xylitol caused a reduction in bacterial counts even in the presence of sucrose.ConclusionsThe continuous-culture biofilm model showed that within a young biofilm, sucrose significantly promotes whereas xylitol reduces bacterial colonization and proliferation. The results indicate that xylitol affects the ability of certain S. mutans strains to adhere to the HA. Clinical studies have also shown that xylitol consumption decreases caries incidence and reduces the amount of plaque. This study contributes to the understanding of the mechanism behind these clinical observations.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U4clPs
via IFTTT

Transcription factor RFX1 is ubiquitinated by E3 ligases STUB1 in systemic lupus erythematosus

Publication date: Available online 6 June 2016
Source:Clinical Immunology
Author(s): Yu Guo, Ming Zhao, Qianjin Lu
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease caused by complex interactions between genes and the environment. The expression level of transcription factor regulatory factor X 1 (RFX1) is reduced in T cells from SLE patients. RFX1 can regulate epigenetic modifications of CD70 and CD11a and plays an important role in the development of SLE. However, the mechanisms that mediate reduction of RFX1 in SLE are unclear. Here, we demonstrate that RFX1 protein expression can be tightly regulated by polyubiquitination-mediated proteosomal degradation via STIP1 homology and U-box containing protein 1 (STUB1). The E3 ligase STUB1 is upregulated in CD4+T cells of SLE patients compared to healthy subjects. Overexpression of STUB1 in CD4+T cells leads to upregulation of levels of CD70 and CD11a in T cells. The modulation of STUB1 activity may provide a novel therapeutic approach for SLE.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1XxDTAV
via IFTTT

Firefighter or Firefighter/Paramedic - Costa Mesa Fire and Rescue

CITY OF COSTA MESA 77 FAIR DRIVE Costa Mesa, CALIFORNIA 92626 Updated: June 03, 2016 Job Classification: Firefighter & Firefighter/Paramedic Costa Mesa Fire and Rescue is currently recruiting for the position of Firefighter and Firefighters with Paramedic license. On-line City applications and required documentation may be submitted starting 8:00 a.m. on Wednesday, June 15, 2016 through 11:59 p.m ...

from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1XxBNRw
via IFTTT

Paramedic Full and Part Time - MED-Star Paramedic Ambulance, Inc.

Med-Star Paramedic Ambulance Service in Brandon, SD is excited to announce that we currently have full time and part time Paramedic positions available. We offer competitive pay including overtime, flexible scheduling with 12 and 24 hour shifts available.. For an application please call our office 605-582-6096, Required license or certification: South Dakota Osteopathic License and Valid Drivers License ...

from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t1WEyY
via IFTTT

Sky-Blue Organic Light Emitting Diode with 37% External Quantum Efficiency Using Thermally Activated Delayed Fluorescence from Spiroacridine-Triazine Hybrid

Thumbnail image of graphical abstract

Extremely efficient sky-blue organic electroluminescence with external quantum efficiency of ≈37% is achieved in a conventional planar device structure, using a highly efficient thermally activated delayed fluorescence emitter based on the spiroacridine-triazine hybrid and simultaneously possessing nearly unitary (100%) photoluminescence quantum yield, excellent thermal stability, and strongly horizontally oriented emitting dipoles (with a horizontal dipole ratio of 83%).



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PAJJhW
via IFTTT

Enhanced Singlet Oxygen Generation in Oxidized Graphitic Carbon Nitride for Organic Synthesis

Thumbnail image of graphical abstract

Experimental data reveal that the incorporation of carbonyl groups into polymer matrix can significantly enhance singlet oxygen (1O2) generation and suppress other reactive oxygen species production. Excitonic processes interrogated with phosphorescence spectroscopy reveal enhanced triplet-exciton generation in the modified g-C3N4, which facilitate 1O2 generation through energy transfer process. Benefiting from this, the modified g-C3N4 shows excellent conversion and selectivity in organic synthesis.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t28Lfn
via IFTTT

Mobile phones and seizures: drug-resistant epilepsy is less common in mobile-phone-using patients

Background

Epilepsy is a condition where patients have seizures due to abnormal nerve impulses in the brain. The effect of mobile phone radiation on patients with seizures is not known.

Objective

To compare the seizure profile of patients not using mobile phones with that of their peers using mobile phones.

Methods

In a retrospective cohort study performed at the neurology outpatient department of Guntur Medical College Hospital, Guntur, India from September 2014 to September 2015, we included 178 consecutive epileptic patients aged 16–65 years, who had had seizure disorder for 1 year or more. On the basis of their possession and usage of mobile phones, patients were divided into three groups: no mobile group (NMG), home mobile group (HMG) and personal mobile group (PMG). We obtained data on seizure frequency and recorded details of mobile phone usage and their antiepileptic drug (AED) treatment.

Results

107 NMG, 3 HMG and 68 PMG patients were finalised for the analysis. There was no significant difference in the number of seizures in the past year between the three groups. The PMG (3.7%) contained a clinically significant lower proportion of patients with drug-resistant epilepsy than the NMG (28.2%). Patients with drug-responsive epilepsy were 7.4 (95% CI 1.4 to 39.9) (p=0.01) times more likely to be found in the PMG than in the NMG after adjustment for differences in sex and occupation.

Conclusions

Although the experimental data remain inconclusive, our clinical study suggests that patients who use mobile phones are less likely to have drug-resistant epilepsy.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/213rbaQ
via IFTTT

Ellipsys Vascular Percutaneous System for AV Fistulas Gets EU Green Light

eLLIPSYSAvenu Medical, a firm based in San Juan Capistrano, California, won European CE Mark approval to introduce its minimally invasive and cost effective Ellipsys Vascular Access System for creating arteriovenous (AV) fistulas in dialysis patients.

Ellipsys-tipSome details about the device according to the company,

The system enables physicians to percutaneously access the proximal radial artery in the forearm to create an AV fistula. Under high frequency ultrasound guidance, the Ellipsys System uses a novel outer access cannula, guidewire and vessel capture construct that creates a connection of the vein to the artery using an intravascular approach.

A select amount of low power thermal energy is used to cut the walls of the vessels and fuse the tissue, creating an in-vivo anastomosis without leaving any foreign material (including sutures) in the resulting AV fistula. The use of thermal energy has been successfully used in other vessel sealing applications with results equal to or better than traditional suturing methods.

The technology is currently under an Investigational Device Exemption by the FDA in the U.S.

Here's Avenu Medical's animation demonstrating how the device is used:

Product page: Ellipsys Vascular Access System…

Via: Avenu Medical…

The post Ellipsys Vascular Percutaneous System for AV Fistulas Gets EU Green Light appeared first on Medgadget.

Medgadget?d=yIl2AUoC8zA Medgadget?d=qj6IDK7rITs Medgadget?i=CLiv7Egd5Jc:ewx-VKt1yxc:gIN9


from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t27wgv
via IFTTT

Current status of the implantable LVAD

Abstract

With the ongoing shortage of available organs for heart transplantation, mechanical circulatory support devices have been increasingly utilized for managing acute and chronic heart failure that is refractory to medical therapy. In particular, the introduction of the left ventricular assist devices (LVAD) has revolutionized the field. In this review, we will discuss a brief history of the LVAD, available devices, current indications, patient selection, complications, and outcomes. In addition, we will discuss recent outcomes and advancements in the field of noncardiac surgery in the LVAD patient. Finally, we will discuss several topics for surgical consideration during LVAD implantation.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/28fHvLd
via IFTTT

Observation of the efficacy of radiofrequency catheter ablation on patients with different forms of atrial fibrillation

OBJECTIVE: To study the efficacy and safety of radiofrequency catheter ablation (RFCA) in patients with different forms of atrial fibrillation.

PATIENTS AND METHODS: By retrospective analysis, we summarize 720 cases, where patients diagnosed with atrial fibrillation in our hospital were treated with RFCA from February 2010 to October 2014. Among the cases, 425 were diagnosed with paroxysmal atrial fibrillation and 295 with non-paroxysmal atrial fibrillation (including persistent atrial fibrillation and permanent atrial fibrillation). All patients were followed up until June 2015 to compare and analyze the differences in operation success rates, complications and recurrence rates.

RESULTS: 395 cases (92.9%) of paroxysmal atrial fibrillation and 253 cases (85.8%) with non-paroxysmal atrial fibrillation were subject to surgery and followed up. The age of onset, disease course, underlying diseases, left atrial diameter and combined anti-arrhythmics of patients with paroxysmal atrial fibrillation were lower than those of patients with non-paroxysmal atrial fibrillation, and the differences were statistically significant (p<0.05). The success rate of the first ablation was higher than that of non-paroxysmal atrial fibrillation. Procedure time, procedure method, complications and recurrence rate of patients with paroxysmal atrial fibrillation were lower than those of non-paroxysmal atrial fibrillation group, and the differences were statistically significant (p<0.05). When we compared apoplexy and heart failure caused by atrial fibrillation in the two groups, the difference was not statistically significant (Apoplexy: p=0.186; Heart failure: p=0.170).

CONCLUSIONS: The individual ablation success rate was higher for paroxysmal atrial fibrillation, and long-term follow-up showed that the occurrence of apoplexy and heart failure was not different from the non-paroxysmal atrial fibrillation group.

L'articolo Observation of the efficacy of radiofrequency catheter ablation on patients with different forms of atrial fibrillation sembra essere il primo su European Review.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1t24hWj
via IFTTT

ARID1A alteration in aggressive urothelial carcinoma and variants of urothelial carcinoma

Publication date: September 2016
Source:Human Pathology, Volume 55
Author(s): Jianhong Li, Shaolei Lu, Kara Lombardo, Rene Monahan, Ali Amin
ARID1A mutation leads to loss of the products of this tumor-suppressor gene. Studies demonstrated ARID1A mutation in 20% of stage IV urothelial carcinomas (UCs) with worse prognosis. The expression of ARID1A in aggressive variants of UC is not studied properly. From 2000 to 2015, 81 variants of UC (29 micropapillary, 33 sarcomatoid, 31 small cell, 2 nested, and 3 plasmacytoid variants) were identified in the archives of Rhode Island Hospital. Immunohistochemistry for anti-ARID1A antibody (Sigma-Aldrich, St Louis, MO) was performed. The staining pattern was semiquantitatively scored, and results were analyzed by Fisher exact test (2 tailed) on contingency tables, survival curve, and log-rank test. Patients were predominantly male (78%) with mean age of 67.9 years. The plasmacytoid variant group occurred in younger ages (mean: 54 years). Half of the specimens contained concurrent conventional UCs. Normal urothelium invariably exhibited strong ARID1A nuclear staining. There was no difference in expression between upper and lower tracts. ARID1A expression was lower in the variants compared with conventional UCs (P<.0001). In micropapillary UCs, an inverse correlation between stage and ARID1A expression was noted, with significant correlation between ARID1A expression and overall survival (P=.0221). Sarcomatoid UCs and small cell CCs showed lower ARID1A expression compared with UCs that was not statistically significant, and neither showed any significant correlation with stage or overall survival. ARID1A expression is significantly decreased in higher stages of UC and its aggressive variants; therefore, ARID1A mutation appears to play an important role in the prognosis of UC and its aggressive variants. This finding may have therapeutic implications.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1U4aF8r
via IFTTT

Microbial complexes levels in conventional and self-ligating brackets

Abstract

Objectives

The aims were to evaluate the levels of bacterial species in saliva and in situ and to assess whether the design of brackets influences the risk of developing periodontal disease.

Materials and methods

Twenty patients (13.3 mean age) were bonded with self-ligating brackets and a conventional bracket. Saliva was collected before bonding and 30 and 60 days after bonding. One sample of each bracket was removed 30 and 60 days after bonding. The analysis was determined by checkerboard DNA–DNA hybridization. The data was evaluated by the non-parametric test.

Results

A significant increase in the levels of bacterial species in the saliva occurred in 15 of the 22 analyzed species. The self-ligating brackets presented the highest incidence percentages for the orange and red complexes 60 days after bonding. In situ analyses showed different patterns according to the bracket design. The levels of Campylobacter rectus showed significant differences (p = 0.011) 60 days after bonding among the three brackets; the highest values were observed in the In-Ovation®R bracket.

Conclusions

The bracket design seems to influence the levels of bacterial species involved in periodontal disease. Considering the wide variety of bacterial species, additional studies are needed to aid in the establishment of effective protocols to prevent the development of periodontal disease during orthodontic treatment.

Clinical relevance

A dynamic alteration in the oral microbiota may lead to inflammatory reactions in the supporting soft and hard tissues. The different types of brackets interfere with bacterial adherence. Bracket design should be considered in orthodontic treatment.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1PA84UU
via IFTTT

My love-hate relationship with EMS

A recent encounter with a salty EMR-firefighter who had learned all the wrong lessons from EMS, made me wonder why is it that some of us can find rejuvenation after burnout, and others can't" Is it simply a matter of perspective and all it takes to improve your outlook is someone pointing out to you all the good things you've ignored"

Or is it that so many of us come into EMS already broken in some way, hoping that by healing others we can heal ourselves"

For some, that seems to work. For many others, though, it seems to build a callous over the broken edges, so that they may never knit together again.

For my part, I pray that it's simply a matter of perspective. Otherwise, the years I've spent advocating for EMS seem pretty pointless.

I suppose that it's simply a personal decision about what matters more to you — the things you hate about EMS, or the things you love about EMS. As another EMS Week — my 23rd — fades in my rearview mirror, I find that what I hate and what I love about EMS are inextricably linked, and my perspective about which one is more important is changing.

I hate that people call an ambulance for trivial reasons, but I love that I am expected to go.
Anyone who has worked in EMS for more than five minutes has encountered a patient that called an ambulance for something that wasn't strictly defined as an emergency. Whether it is ignorance or blatant abuse, it happens far more often than it should.

Much of it stems from two generations of citizens being constantly told — often by EMS itself — that the slightest twinge or sniffle might herald something serious and to call 911. And while blatant abuse and gaming the system for free medical care, a meal or a ride across town is still somewhat rare, most of us have encountered those patients.

Dealing with them gnaws at my job satisfaction like a rat gnaws at your electrical wiring, building a cozy little nest with the remnants of my idealism, a nest that threatens to one day burst into flame and destroy everything I hold dear.

But I also love the honor in the implicit compact between the people who call 911 and the people who respond; you call, we come. There is a beauty in the simplicity of it.

You call. We come.

Young, old, wealthy, poor, trivial or life-threatening, wealthy philanthropist or felonious meth dealer, in America it's a pretty safe bet that when you call an ambulance, an ambulance will come.

The system isn't perfect. It's riddled with cracks and flaws, and often takes longer than it should. But the people within it make an earnest attempt to respond to your call for help, each and every time.

We don't look at your neighborhood on a map and decide if your socioeconomic status or ethnicity is worthy of our care. When the car crash victim turns out to be the drunk driver who killed a family of three, we render the same care had the roles been reversed.

And many of us pay a tremendous emotional price for it. There's an emotional burden in always being the good guys.

While many of us may try to ease that burden with bitching and complaining to our peers, or engaging in black humor that horrifies the occasional outsider who happens to overhear, when the tones drop, we put all that away and we respond.

You call. We come.

I take great pride in that. I condemn systems abuse as much as the next guy, but I honestly wonder if screening calls for appropriate utilization of 911 doesn't chip away at the honor of my part in the compact.

You call, we come.

It doesn't even occur to me not to respond. I'm not wired that way.

I hate that EMS has changed me, yet the man I was sorely needed to change.
Death holds no fear or fascination for me anymore. Car accidents, shootings, stabbings, blood and gore — they're just meat. Because I'm good at compartmentalizing, people who don't know me think I can be cold and uncaring.

And I suppose I can be. I worry about that myself sometimes. On a call a few years back, a horse in the roadway caused a multi-vehicle crash. As I lifted the shattered head of the first victim I triaged and her uninjured husband begged me to help her, I thought to myself, "Dead meat. Find the next patient."

And that's exactly what I did.

I flash back to that call sometimes, and fear grips my heart in its leaden fist, as I wonder, "How much have I had to carve off of my soul to make that decision so automatically" And will I have any left to give to my daughter, my girlfriend and my friends""

But when I think back on it, there wasn't much to like about the person I used to be before EMS. He was cocky and arrogant. He was superficial. He was the quintessential class clown, hiding his pain behind a mask of humor.

He had been hurt so much as a child, that he held everyone at arm's length. He loved no one, and dared let no one come close enough to love him.

The young paramedic I was used to avoid funerals. Funerals were events where people expressed uncomfortable emotions like grief and sorrow, things I'd rather avoid.

Now, I've learned that pain and sorrow are nothing to fear. I have borne witness to more pain and suffering, more grief, sorrow and death than most non-EMS people can ever fathom.

Each passing year teaches me to hold my loved ones close, and to treasure every moment. I'm a better man, a better father and a better boyfriend because of what EMS has taught me.

If I seem more weary and scarred these days, it's only because my aches have been earned. A full life weighs more than an empty one.

I hate that EMS has taken so many of my friends, but they all died doing what they loved.
I've lost friends to helicopter and ambulance crashes. A few died by suicide.

Others left EMS after back injuries, patient assaults or burnout. They are still alive, but EMS changed them so drastically that they're not the same people I once knew.

I advocate tirelessly for better ambulance design, more appropriate use of helicopter EMS and more stringent safety standards and practices. I do this because I don't want to lose any more brothers and sisters in EMS — not even the ones I've yet to meet.

When I think about the friends I've lost, not a one of them would have chosen to die of old age in a nursing home. Old age, yes, but not in a nursing home.

To go into cardiac arrest right after they got ROSC on somebody else, that's the way they'd have wanted to go. Or maybe they'd pick a massive stroke right during a night of passion with the supermodel you met when you saved her life … yep, in the ambulance.

I hate dealing with drunks, but drunks are endlessly entertaining.
Be it angry and belligerent, weepy and maudlin or rambling and incoherent, I've never been able to master any of the dialects of drunkese. I have been sexually propositioned, threatened with an ass kicking, and proposed marriage by more drunks than I can count — and often all three by the same drunk.

Dealing with drunk patients taxes every bit of professionalism, customer service skills and civility I can muster. I am ashamed to say that I have sometimes failed at it.

On the other hand, I have laughed uproariously with and at some of my drunk patients. Many of the most entertaining people in the back of my ambulance were there because they imbibed "tee many martoonis."

And for a writer, drunks are a gold mine of entertaining material. A wise man once said that no entertaining story ever begins with, "So there I was, eating a salad …"

Looking back on my career, it's the perspective earned from 23 years in EMS that has taught me that for every gripe and complaint about what my job entails, there's a "yeah, but" in my memories. So far, all those "buts" make everything else worth it.

Here's hoping your collection of "yeah, buts" make everything else worth it as well.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/1UtU9vu
via IFTTT

One-Dimensional Finite Element Method Solution of a Class of Integro-Differential Equations: Application to Non-Fickian Transport in Disordered Media

Abstract

We study an integro-differential equation that has important applications to problems of anomalous transport in highly disordered media. In one application, the equation is the continuum limit of a continuous time random walk used to quantify non-Fickian (anomalous) contaminant transport. The finite element method is used for the spatial discretization of this equation, with an implicit scheme for its time discretization. To avoid storage of the entire history, an efficient sum-of-exponential approximation of the kernel function is constructed that allows a simple recurrence relation. A 1D formulation with a linear element is implemented to demonstrate this approach, by comparison with available experiments and with an exact solution in the Laplace domain, transformed numerically to the time domain. The proposed scheme convergence assessment is briefly addressed. Future extensions of this implementation are then outlined.



from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/22JCo1y
via IFTTT