13 research outputs found
Surface-enhanced Raman spectroscopy study of 4-ATP on gold nanoparticles for basal cell carcinoma fingerprint detection
The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloidal gold nanoparticles with size distribution of 2 to 5 nm were used as a labeling agent to detect basal cell carcinoma (BCC) of the skin. The enhanced Raman band at 1075 cm-1 corresponding to the C-S stretching vibration in 4-ATP was observed during attachment to the surface of the gold nanoparticles. The frequency and intensity of this band did not change when the colloids were conjugated with BerEP4 antibody, which specifically binds to BCC. We show the feasibility of imaging BCC by surface-enhanced Raman spectroscopy, scanning the 1075 cm-1 band to detect the distribution of 4ATP-coated gold nanoparticles attached to skin tissue ex vivo
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A review of advanced air distribution methods - theory, practice, limitations and solutions
Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review
Study of crosswind effects on the dynamics and aerodynamics of high-speed vehicles.
The research on the crosswind field on the circulation of railway vehicles
became noteworthy in the 90s with the development of high-speed trains. The
European project TRANSAERO (Schulte-Werning et al., 2002) was the starting point
since it was able to attract the attention of both the scientific community and the
rolling stock manufacturers. Crosswinds are a safety matter and one of the key
factors that are able to stop the continuous speed increase requested to the rail
transportation.
The study of the effect of crosswinds on vehicles problem requires a global vision
since it involves both the dynamics and the aerodynamics of the vehicle. It is a
coupled problem that requires a multidisciplinary approach and therefore the thesis
addresses the problem from both perspectives. The sections centered on the vehicle
dynamics firstly study 2D models and their benefit to extract conclusions in regard to
the vehicle safety and comfort. The wheel unloading ratio is the factor used by
standards to guarantee the safeness of the vehicle in the crosswind context.
Conclusions show that a simplified model is able to provide wheel unloading factors
with small rates of error. Moreover, crosswinds can also become a problem from the
point of view of the vehicle’s comfort. By using full multibody models, we checked
that the case of circulation on a curved track under lateral wind sets especially
adverse conditions that can constraint the vehicle to reduce the travel speed in cases
of high wind speeds. We observed that the vehicle described a yawing movement that
made it to become instable, which reduced significantly the ride quality.
The thesis describes previous aerodynamic research on the three-dimensional flow
around high-speed trains in a crosswind scenario. However, the effect of the
infrastructure is important and any modification at the surroundings of the vehicle
alters the flow. At this respect, the thesis studies the sheltering effect of wind fences.
Firstly, 2D computations have been used to carry out a parametric study of the fence
design and to validate the value of simplified models. This work shows that 2D
models are valid to find a set of fence designs to carry more detailed simulations in
the 3D space.
The goal of measuring the sheltering effect of wind-breaking devices in the 3D space
was to obtain the aerodynamic coefficients of the vehicle using some of the fence
designs that were used in the 2D model. The proposal herein presented is based on
the use of a meshless CFD (Computational Fluid Dynamics) code that is based on the
Lattice-Boltzmann Method (LBM). Results prove that these codes provide results with
a reasonable margin of error at the range of yaw angles of interest for this
investigation
Study of crosswind effects on the dynamics and aerodynamics of high-speed vehicles.
The research on the crosswind field on the circulation of railway vehicles
became noteworthy in the 90s with the development of high-speed trains. The
European project TRANSAERO (Schulte-Werning et al., 2002) was the starting point
since it was able to attract the attention of both the scientific community and the
rolling stock manufacturers. Crosswinds are a safety matter and one of the key
factors that are able to stop the continuous speed increase requested to the rail
transportation.
The study of the effect of crosswinds on vehicles problem requires a global vision
since it involves both the dynamics and the aerodynamics of the vehicle. It is a
coupled problem that requires a multidisciplinary approach and therefore the thesis
addresses the problem from both perspectives. The sections centered on the vehicle
dynamics firstly study 2D models and their benefit to extract conclusions in regard to
the vehicle safety and comfort. The wheel unloading ratio is the factor used by
standards to guarantee the safeness of the vehicle in the crosswind context.
Conclusions show that a simplified model is able to provide wheel unloading factors
with small rates of error. Moreover, crosswinds can also become a problem from the
point of view of the vehicle’s comfort. By using full multibody models, we checked
that the case of circulation on a curved track under lateral wind sets especially
adverse conditions that can constraint the vehicle to reduce the travel speed in cases
of high wind speeds. We observed that the vehicle described a yawing movement that
made it to become instable, which reduced significantly the ride quality.
The thesis describes previous aerodynamic research on the three-dimensional flow
around high-speed trains in a crosswind scenario. However, the effect of the
infrastructure is important and any modification at the surroundings of the vehicle
alters the flow. At this respect, the thesis studies the sheltering effect of wind fences.
Firstly, 2D computations have been used to carry out a parametric study of the fence
design and to validate the value of simplified models. This work shows that 2D
models are valid to find a set of fence designs to carry more detailed simulations in
the 3D space.
The goal of measuring the sheltering effect of wind-breaking devices in the 3D space
was to obtain the aerodynamic coefficients of the vehicle using some of the fence
designs that were used in the 2D model. The proposal herein presented is based on
the use of a meshless CFD (Computational Fluid Dynamics) code that is based on the
Lattice-Boltzmann Method (LBM). Results prove that these codes provide results with
a reasonable margin of error at the range of yaw angles of interest for this
investigation
Pilot study describing the design process of an oil sump for a competition vehicle by combining additive manufacturing and carbon fibre layers
Formula Student is an international competition governed by the Society of Automotive Engineers (SAE) which challenges university students to design and build a racing car that will subsequently be compared against other cars from universities around the world on homologated racing circuits by non-professional drivers. This study focuses on the design, analysis and manufacturing process of a new oil sump for a Formula Student car - which involves combining a main ABS-plastic core created by an additive manufacturing (AM) printing process and a manual lay-up process with carbon fibre - in order to reduce the sloshing effect due to the movement of the oil during racing. The new oil sump and the original sump were modelled with computer-aided design (CAD) software and five computational fluid dynamics (CFD) simulations were performed to compare the sloshing effect in both designs in three driving scenarios: acceleration, braking and changing direction. The simulations showed that acceleration is not a critical situation since the new internal design of the sump was capable of delaying the immersion time of the oil pick-up pipe from 0.75 seconds to 2 seconds during braking and from 0.4 seconds to 0.8 seconds during lateral acceleration. The new design was physically manufactured and subsequently integrated into an internal combustion engine for testing for 45 minutes. During this test, the engine was started and put at 9600 RPM, so the oil worked under realistic temperature conditions (80 degrees C). It did not present any oil leak. After testing, it was disassembled and visually inspected. No failure in the inner surfaces of the oil sump was observed due to temperature. According to these results, the present research argues that the combination of AM technology (i.e., fused deposition modelling) and layers of carbon fibre is a real alternative to conventional manufacturing processes in order to create geometrically complex oil sumps that minimise the sloshing effect in competition automobiles
Efficacy of triple therapy with a proton pump inhibitor, levofloxacin, and amoxicillin as first-line treatment to eradicate Helicobacter pylori Eficacia de una triple terapia con un inhibidor de la bomba de protones, levofloxacino y amoxicilina, como primer tratamiento, en la erradicación de Helicobacter pylori
Background: triple therapy including a proton pump inhibitor, clarithromycin, and amoxicillin (PPI-CA) is the first-choice treatment used for H. pylori eradication. The efficacy of this treatment is declining of late, and alternative therapies are currently under evaluation. Objectives: to evaluate the efficacy, safety and compliance of a triple therapy with a PPI, amoxicillin and levofloxacin (PPI-LA) - replacing clarithromycin - for the eradication of H. pylori. Methods: the study included 135 patients (65% women), mean age 53 years, with dyspeptic symptoms and H. pylori infection proven by a positive urease rapid test, histological analysis, or C13-urea breath test. Diagnosis: non-investigated dyspepsia 48.9%, functional dyspepsia 36.3%, and ulcerative dyspepsia 14.8%. Treatment was indicated with a proton pump inhibitor at usual doses, amoxicillin 1 g, and levofloxacin 500 mg, administered jointly during breakfast and dinner for 10 days. We studied the performance of this triple therapy and its effects using a questionnaire, and effectiveness by the negativity of the C13-urea breath test after 6-8 weeks after treatment discontinuation. Per protocol, we compared the effectiveness of PPI-LA with a control group of 270 patients treated with PPI-CA for 10 days. Results: 130 patients (96.2%) could complete the treatment and follow-up protocol. Effectiveness (intention to treat) was 71.8% (97/135) and 74.6% (per protocol) (97/130). Sixteen patients (11.8%) had well-tolerated adverse effects, except for 5 subjects (3.7%) who dropped out. PPI-CA was effective (per protocol) in 204 patients out of 270 (75.5%) in the control group. Conclusions: triple therapy with a PPI, amoxicillin and levofloxacin for 10 days is a well-tolerated treatment that is easy to comply with; however it has low efficiency - less than 80% - and is not recommended as a first-choice treatment for H. pylori eradication. Similar results were obtained with the classic triple therapy using a PPI, clarithromycin and amoxicillin.<br>Introducción: la triple terapia con un inhibidor de la bomba de protones, claritromicina y amoxicilina (IBP-CA) es el tratamiento de primera elección más utilizado en la erradicación de H. pylori. La eficacia de este tratamiento está disminuyendo en los últimos años y se están valorando otras alternativas terapéuticas. Objetivos:valorar la eficacia, cumplimiento y seguridad de una triple terapia con un IBP, amoxicilina y levofloxacino, sustituyendo a la claritromicina, en la erradicación de H. pylori. Métodos: periodo de estudio: 2007-2008. Se incluyen 135 pacientes (65% mujeres), edad media de 53 años, con síntomas dispépticos e infección por H. pylori, constatada por positividad del test rápido de la ureasa, histología o prueba del aliento con urea-C13. Diagnósticos: dispepsia no investigada: 48,9%, dispepsia funcional: 36,3% y dispepsia ulcerosa: 14,8%. Se indica tratamiento con un inhibidor de la bomba de protones, a dosis habitual, amoxicilina 1 g y levofloxacino 500 mg (IBP-LA), administrados de forma conjunta en desayuno y cena, durante 10 días. Se valora el cumplimiento de la triple terapia y sus efectos adversos mediante interrogatorio y su eficacia mediante la negatividad de la prueba del aliento con urea-C13 practicada a las 6-8 semanas del término del tratamiento. Se compara la eficacia, por protocolo, del tratamiento con IBP-LA con la observada en un grupo control de 270 pacientes tratados con IBP-CA durante 10 días en los años 2006-2007. Resultados: 130/135 pacientes (96,2) del grupo de estudio completaron el tratamiento y el protocolo del seguimiento. La eficacia por intención de tratar fue del 71,8% (97/135) y por protocolo del 74,6% (97/130). Dieciséis pacientes (11,8%) presentaron efectos adversos bien tolerados, excepto en 5 pacientes (3.7%) que motivan el abandono del tratamiento. El tratamiento con IBP-CA resultó eficaz, por protocolo, en 204/270 (75,5%) pacientes del grupo control. Conclusiones: la triple terapia con un IBP, amoxicilina y levofloxacino durante 10 días es un tratamiento bien tolerado, con fácil cumplimiento, pero con una baja eficacia, inferior al 80%, similar a la obtenida con la triple terapia clásica con un IBP, claritromicina y amoxicilina, no siendo un tratamiento de primera elección recomendable, en nuestra área sanitaria, en la erradicación de H. pylori
Computational study of a novel catheter for liver radioembolization
Radioembolization (RE) is a medical treatment for primary and secondary liver can-cer that involves the transcatheter intraarterial delivery of micron-sized andradiation-emitting microspheres, with thegoal of improving microsphere depositionin the tumoral bed while sparing healthytissue. An increasing number of in vitroand in silico studies on RE in the literature suggest that the particle injection veloc-ity, spatial location of the catheter tip and catheter type are important parameters inparticle distribution. The present in silico study assesses the performance of a novelcatheter design that promotes particle dispersion near the injection point, with thegoal of generating a particle distribution that mimics the flow split to facilitatetumour targeting. The design is based on two factors: the direction and the velocityat which particles are released from the catheter. A series of simulations was per-formed with the catheter inserted at an idealised hepatic artery tree with physiologi-cally realistic boundary conditions. Two longitudinal microcatheter positions in thefirst generation of the tree were studied by analysing the performance of the cathe-ter in terms of the outlet-to-outlet particle distribution and split flow matching. Theresults show that the catheter with the best performance is one with side holes onthe catheter wall and a closed frontal tip. This catheter promotes a flow-split-matching particle distribution, which improves as the injection crossflow increases
Computational study of a novel catheter for liver radioembolization
Radioembolization (RE) is a medical treatment for primary and secondary liver can-cer that involves the transcatheter intraarterial delivery of micron-sized andradiation-emitting microspheres, with thegoal of improving microsphere depositionin the tumoral bed while sparing healthytissue. An increasing number of in vitroand in silico studies on RE in the literature suggest that the particle injection veloc-ity, spatial location of the catheter tip and catheter type are important parameters inparticle distribution. The present in silico study assesses the performance of a novelcatheter design that promotes particle dispersion near the injection point, with thegoal of generating a particle distribution that mimics the flow split to facilitatetumour targeting. The design is based on two factors: the direction and the velocityat which particles are released from the catheter. A series of simulations was per-formed with the catheter inserted at an idealised hepatic artery tree with physiologi-cally realistic boundary conditions. Two longitudinal microcatheter positions in thefirst generation of the tree were studied by analysing the performance of the cathe-ter in terms of the outlet-to-outlet particle distribution and split flow matching. Theresults show that the catheter with the best performance is one with side holes onthe catheter wall and a closed frontal tip. This catheter promotes a flow-split-matching particle distribution, which improves as the injection crossflow increases