International Science Index

International Journal of Biomedical and Biological Engineering

747
94888
Direct Current Electric Field Stimulation against PC12 Cells in 3D Bio-Reactor to Enhance Axonal Extension
Abstract:
In this study, we developed a three-dimensional (3D) direct current electric field (DCEF) stimulation bio-reactor for axonal outgrowth enhancement to generate the neural network of the central nervous system (CNS). By using our newly developed 3D DCEF stimulation bio-reactor, we cultured the rat pheochromocytoma cells (PC12) and investigated the effects on the axonal extension enhancement and network generation. Firstly, we designed and fabricated a 3D bio-reactor, which can load DCEF stimulation on PC12 cells embedded in the collagen gel as extracellular environment. The connection between the electrolyte and the medium using salt bridges for DCEF stimulation was introduced to avoid the cell death by the toxicity of metal ion. The distance between the salt bridges was adopted as the design variable to optimize a structure for uniform DCEF stimulation, where the finite element (FE) analyses results were used. Uniform DCEF strength and electric flux vector direction in the PC12 cells embedded in collagen gel were examined through measurements of the fabricated 3D bio-reactor chamber. Measurement results of DCEF strength in the bio-reactor showed a good agreement with FE results. In addition, the perfusion system was attached to maintain pH 7.2 ~ 7.6 of the medium because pH change was caused by DCEF stimulation loading. Secondly, we disseminated PC12 cells in collagen gel and carried out 3D culture. Finally, we measured the morphology of PC12 cell bodies and neurites by the multiphoton excitation fluorescence microscope (MPM). The effectiveness of DCEF stimulation to enhance the axonal outgrowth and the neural network generation was investigated. We confirmed that both an increase of mean axonal length and axogenesis rate of PC12, which have been exposed 5 mV/mm for 6 hours a day for 4 days in the bioreactor. We found following conclusions in our study. 1) Design and fabrication of DCEF stimulation bio-reactor capable of 3D culture nerve cell were completed. A uniform electric field strength of average value of 17 mV/mm within the 1.2% error range was confirmed by using FE analyses, after the structure determination through the optimization process. In addition, we attached a perfusion system capable of suppressing the pH change of the culture solution due to DCEF stimulation loading. 2) Evaluation of DCEF stimulation effects on PC12 cell activity was executed. The 3D culture of PC 12 was carried out adopting the embedding culture method using collagen gel as a scaffold for four days under the condition of 5.0 mV/mm and 10mV/mm. There was a significant effect on the enhancement of axonal extension, as 11.3% increase in an average length, and the increase of axogenesis rate. On the other hand, no effects on the orientation of axon against the DCEF flux direction was observed. Further, the network generation was enhanced to connect longer distance between the target neighbor cells by DCEF stimulation.
746
94049
Pathogenic Bacteria Isolated from Diseased Giant Freshwater Prawn in Shrimp Culture Ponds
Abstract:
Pathogenic bacterial flora was isolated from giant freshwater prawns, Macrobrachium rosenbergii. The infected shrimp samples were collected from BuaBan Aquafarm at Kalasin Province in Thailand, during June-September 2018. Bacterial species were isolated by serial dilution technique method were plated in TCBS (Thiosulfate Citrate Bile Salt Sucrose) agar medium. The present study, totally 89 colonies were isolated from TCBS agar plates and among these, All colonies were identified by using the API 20E biochemical tests showed the genera Aeromonas, Citrobacter, Chromobacterium, Providencia, Pseudomonas, Stenotrophomonas and Vibrio. The maximum species was recorded in Pseudomonas (50.57%) and minimum was observed in Chromobacterium and Providencia (1.12%).
745
95711
Design of Bacterial Pathogens Identification System Based on Scattering of Laser Beam Light and Classification of Binned Plots
Abstract:
Detection and classification of microbes have a vast range of applications in biomedical engineering especially in detection, characterization, and quantification of bacterial contaminants. For identification of pathogens, different techniques are emerging in the field of biomedical engineering. Latest technology uses light scattering, capable of identifying different pathogens without any need for biochemical processing. Bacterial Pathogens Identification System (BPIS) which uses a laser beam, passes through the sample and light scatters off. An assembly of photodetectors surrounded by the sample at different angles to detect the scattering of light. The algorithm of the system consists of two parts: (a) Library files, and (b) Comparator. Library files contain data of known species of bacterial microbes in the form of binned plots, while comparator compares data of unknown sample with library files. Using collected data of unknown bacterial species, highest voltage values stored in the form of peaks and arranged in 3D histograms to find the frequency of occurrence. Resulting data compared with library files of known bacterial species. If sample data matching with any library file of known bacterial species, sample identified as a matched microbe. An experiment performed to identify three different bacteria particles: Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli. By applying algorithm using library files of given samples, results were compromising. This system is potentially applicable to several biomedical areas, especially those related to cell morphology.
744
94893
Automatic Differential Diagnosis of Melanocytic Skin Tumours Using Ultrasound and Spectrophotometric Data
Abstract:
Cutaneous melanoma is a melanocytic skin tumour, which has a very poor prognosis while is highly resistant to treatment and tends to metastasize. Thickness of melanoma is one of the most important biomarker for stage of disease, prognosis and surgery planning. In this study, we hypothesized that the automatic analysis of spectrophotometric images and high-frequency ultrasonic 2D data can improve differential diagnosis of cutaneous melanoma and provide additional information about tumour penetration depth. This paper presents the novel complex automatic system for non-invasive melanocytic skin tumour differential diagnosis and penetration depth evaluation. The system is composed of region of interest segmentation in spectrophotometric images and high-frequency ultrasound data, quantitative parameter evaluation, informative feature extraction and classification with linear regression classifier. The segmentation of melanocytic skin tumour region in ultrasound image is based on parametric integrated backscattering coefficient calculation. The segmentation of optical image is based on Otsu thresholding. In total 29 quantitative tissue characterization parameters were evaluated by using ultrasound data (11 acoustical, 4 shape and 15 textural parameters) and 55 quantitative features of dermatoscopic and spectrophotometric images (using total melanin, dermal melanin, blood and collagen SIAgraphs acquired using spectrophotometric imaging device SIAscope). In total 102 melanocytic skin lesions (including 43 cutaneous melanomas) were examined by using SIAscope and ultrasound system with 22 MHz center frequency single element transducer. The diagnosis and Breslow thickness (pT) of each MST were evaluated during routine histological examination after excision and used as a reference. The results of this study have shown that automatic analysis of spectrophotometric and high frequency ultrasound data can improve non-invasive classification accuracy of early-stage cutaneous melanoma and provide supplementary information about tumour penetration depth.
743
94936
Peruvian Diagnostic Reference Levels for Patients Undergoing Different X-Rays Procedures
Abstract:
Reference levels for common X-rays procedures have been set in many protocols. In Peru, during quality control tests, the dose tolerance is set by these international recommendations. Nevertheless, further studies can be made to assess the national reality and relate dose levels with different parameters such as kV, mA/mAs, exposure time, type of processing (digital, digitalized or conventional), etc. In this paper three radiologic procedures were taken into account for study, general X-rays (fixed and mobile), intraoral X-rays (fixed, mobile and portable) and mammography. For this purpose, an Unfors Xi detector was used; the dose was measured at a focus - detector distance which varied depending on the procedure, and was corrected afterward to find the surface entry dose. The data used in this paper was gathered over a period of over 3 years (2015-2018). In addition, each X-ray machine was taken into consideration only once. The results hope to achieve a new standard which reflects the local practice, and address the issues of the ‘Bonn Call for Action’ in Peru. For this purpose, the 75% percentile of the dose of each radiologic procedure was calculated. In future quality control services, those machines with dose values higher than the selected threshold should be informed that they surpass the reference dose levels established in comparison other radiological centers in the country.
742
95051
Adobe Attenuation Coefficient Determination and Its Comparison with Other Shielding Materials for Energies Found in Common X-Rays Procedures
Abstract:
Adobe is a construction material that fulfills the same function as a conventional brick. Widely used since ancient times, it is present in an appreciable percentage of buildings in Latin America. Adobe is a mixture of clay and sand. The interest in the study of the properties of this material arises due to its presence in the infrastructure of hospital´s radiological services, located in places with low economic resources, for the attenuation of radiation. Some materials such as lead and concrete are the most used for shielding and are widely studied in the literature. The present study will determine the mass attenuation coefficient of Adobe. The minimum required thicknesses for the primary and secondary barriers will be estimated for the shielding of radiological facilities where conventional and dental X-rays are performed. For the experimental procedure, an X-ray source emitted direct radiation towards different thicknesses of an Adobe barrier, and a detector was placed on the other side. For this purpose, an UNFORS Xi solid state detector was used, which collected information on the difference of radiation intensity. The initial parameters of the exposure started at 45 kV; and then the tube tension was varied in increments of 5 kV, reaching a maximum of 125 kV. The X-Ray tube was positioned at a distance of 0.5 m from the surface of the Adobe bricks, and the collimation of the radiation beam was set for an area of 0.15 m x 0.15 m. Finally, mathematical methods were applied to determine the mass attenuation coefficient for different energy ranges. In conclusion, the mass attenuation coefficient for Adobe was determined and the approximate thicknesses of the most common Adobe barriers in the hospital buildings were calculated for their later application in the radiological protection.
741
91694
The Effect of Shank-Space on the Thermal Performance of Shallow U-Tube Ground Heat Exchangers
Abstract:
Space conditioning accounts for 50% of the energy consumed by Europe’s building stock. Curtailing such an energy consumption through the adoption of energy efficient technologies has now become essential. The Ground Source Heat Pump (GSHP) is one such technology which is capable of delivering heating and cooling with enhanced energy-efficiency. The distinctive component of a GSHP is the Ground Heat Exchanger (GHE) which normally consists of an underground circuit of pipes through which a circulating liquid absorbs or rejects heat. As ground temperatures get increasingly stable with depth, vertical GHE, consisting of a U-tube encased within a borehole backfilled with thermally conductive grout, are the most common setup. Research on GHE has mainly focused on either improving the materials used (e.g., pipework, grout) or improving the configuration adopted (e.g., the centre-to-centre distance between the two vertical pipe branches of a U-tube, i.e., the shank-space or the borehole spacing arrangement). Specifically, in relation to shank-space, researchers have observed how the shank-space is an important factor which may influence the heat transfer performance of U-tube GHE. In this area, most of the research carried out has focused on vertical boreholes with typical depths of around 100m, as commercially these are the ones which are used, primarily to ensure that enough contact area to reject or absorb the heat is available. However, reaching such depths is not always possible and other design limitations, such as for example, the requirement for limited interaction with the water table, may require that a system makes use of shallower GHE (up to 50m depth). To the authors’ best knowledge, specific research on shallow GHE is however lacking. To address this aspect, a 3D steady-state Computational Fluid Dynamics (CFD) model of a U-tube GHE was used to investigate the influence of varying shank-spaces on the thermal performance of two isolated vertical shallow U-tube GHE, one 20m deep and the other 40m deep. Borehole diameter was taken as 0.3m. To facilitate the computational process, the simplified 3D steady-state CFD model makes use of an innovative approach, whereby the U-junction at the bottom of the U-tube is eliminated. To ensure confidence in the results obtained using this simplified model, the model was first validated against available experimental and numerical studies performed for full U-tube models. As one would expect, the results show that for the 20m deep borehole containing the vertical U-tube, the temperature drop of the circulating fluid varies for different shank-spaces and is lowest for the closest shank space (0.76K) and highest for the widest shank-space (0.85K). It is observed however that this temperature drop is not linear with increases in shank-space and that for the modelled setup, thermal performance improvement drastically diminishes beyond the 0.15m shank-space, and is practically insignificant for the 0.205m and the 0.26m shank-spaces. Similar results, although with higher values were obtained for the 40m deep 0.3m diameter borehole/U-tube configuration, indicating that for shallow U-tube GHE absolute temperature of the fluid is more dependent on the length of pipework than the effect of shank-space.
740
92315
Determination of the Relative Humidity Profiles in an Internal Micro-Climate Conditioned Using Evaporative Cooling
Abstract:
Driven by increased comfort standards, but at the same time high energy consciousness, energy-efficient space cooling has become an essential aspect of building design. Its aims are simple, aiming at providing satisfactory thermal comfort for individuals in an interior space using low energy consumption cooling systems. In this context, evaporative cooling is both an energy-efficient and an eco-friendly cooling process. In the past two decades, several academic studies have been performed to determine the resulting thermal comfort produced by an evaporative cooling system, including studies on temperature profiles, air speed profiles, effect of clothing and personnel activity. To the best knowledge of the authors, no studies have yet considered the analysis of relative humidity (RH) profiles in a space cooled using evaporative cooling. Such a study will determine the effect of different humidity levels on a person's thermal comfort and aid in the consequent improvement designs of such future systems. Under this premise, the research objective is to characterise the resulting different RH profiles in a chamber micro-climate using the evaporative cooling system in which the inlet air speed, temperature and humidity content are varied. The chamber shall be modelled using Computational Fluid Dynamics (CFD) in ANSYS Fluent. Relative humidity shall be modelled using a species transport model while the k-ε RNG formulation is the proposed turbulence model that is to be used. The model shall be validated with measurements taken using an identical test chamber in which tests are to be conducted under the different inlet conditions mentioned above, followed by the verification of the model's mesh and time step. The verified and validated model will then be used to simulate other inlet conditions which would be impractical to conduct in the actual chamber. More details of the modelling and experimental approach will be provided in the full paper The main conclusions from this work are two-fold: the micro-climatic relative humidity spatial distribution within the room is important to consider in the context of investigating comfort at occupant level; and the investigation of a human being's thermal comfort (based on Predicted Mean Vote – Predicted Percentage Dissatisfied [PMV-PPD] values) and its variation with different locations of relative humidity values. The study provides the necessary groundwork for investigating the micro-climatic RH conditions of environments cooled using evaporative cooling. Future work may also target the analysis of ways in which evaporative cooling systems may be improved to better the thermal comfort of human beings, specifically relating to the humidity content around a sedentary person.
739
93163
Thermal Simulation for Urban Planning in Early Design Phases
Abstract:
Thermal simulations are used to evaluate comfort and energy consumption of buildings. However, the performance of different urban forms cannot be assessed precisely if an environmental control system and user schedules are considered. The outcome of such analysis would lead to conclusions that combine the building use, operation, services, envelope, orientation and density of the urban fabric. The influence of these factors varies during the life cycle of a building. The orientation, as well as the surroundings, can be considered a constant during the lifetime of a building. The structure impacts the thermal inertia and has the largest lifespan of all the building components. On the other hand, the building envelope is the most frequent renovated component of a building since it has a great impact on energy performance and comfort. Building services have a shorter lifespan and are replaced regularly. With the purpose of addressing the performance, an urban form, a specific orientation, and density, a thermal simulation method were developed. The solar irradiation is taken into consideration depending on the outdoor temperature. Incoming irradiation at low temperatures has a positive impact increasing the indoor temperature. Consequently, overheating would be the combination of high outdoor temperature and high irradiation at the façade. On this basis, the indoor temperature is simulated for a specific orientation of the evaluated urban form. Thermal inertia and building envelope performance are considered additionally as the materiality of the building. The results of different thermal zones are summarized using the 'Degree day method' for cooling and heating. During the early phase of a design process for a project, such as Masterplan, conclusions regarding urban form, density and materiality can be drawn by means of this analysis.
738
96244
Use of Shipping Containers as Office Buildings in Brazil: Thermal and Energy Performance for Different Constructive Options and Climate Zones
Abstract:
Shipping containers are present in different Brazilian cities, firstly used for transportation purposes, but which become waste materials and an environmental burden in their end-of-life cycle. In the last decade, in Brazil, some buildings made partly or totally from shipping containers started to appear, most of them for commercial and office uses. Although the use of a reused container for buildings seems a sustainable solution, it is very important to measure the thermal and energy aspects when they are used as such. In this context, this study aims to evaluate the thermal and energy performance of an office building totally made from a 12-meter-long, High Cube 40’ shipping container in different Brazilian Bioclimatic Zones. Four different constructive solutions, mostly used in Brazil were chosen: (1) container without any covering; (2) with internally insulated drywall; (3) with external fiber cement boards; (4) with both drywall and fiber cement boards. For this, the DesignBuilder with EnergyPlus was used for the computational simulation in 8760 hours. The EnergyPlus Weather File (EPW) data of six Brazilian capital cities were considered: Curitiba, Sao Paulo, Brasilia, Campo Grande, Teresina and Rio de Janeiro. Air conditioning appliance (split) was adopted for the conditioned area and the cooling setpoint was fixed at 25°C. The coefficient of performance (CoP) of air conditioning equipment was set as 3.3. Three kinds of solar absorptances were verified: 0.3, 0.6 and 0.9 of exterior layer. The building in Teresina presented the highest level of energy consumption, while the one in Curitiba presented the lowest, with a wide range of differences in results. The constructive option of external fiber cement and drywall presented the best results, although the differences were not significant compared to the solution using just drywall. The choice of absorptance showed a great impact in energy consumption, mainly compared to the case of containers without any covering and for use in the hottest cities: Teresina, Rio de Janeiro, and Campo Grande. This study brings as the main contribution the discussion of constructive aspects for design guidelines for more energy-efficient container buildings, considering local climate differences, and helps the dissemination of this cleaner constructive practice in the Brazilian building sector.
737
92839
A Gastro-Intestinal Model for a Rational Design of in vitro Systems to Study Drugs Bioavailability
Abstract:
This work focuses on a mathematical model able to describe the gastrointestinal physiology and providing a rational tool for the design of an artificial gastro-intestinal system. This latter is mainly devoted to analyse the bioavailability of drugs and nutrients through in vitro tests in order to overcome (or, at least, to partially replace) in vivo trials. The model structure consists of four 'reactive' compartments (stomach, duodenum, jejunum, and blood) interconnected through pipes and valves. The enzymatic reactions are described through the Michaelis-Menten kinetic equations, characterized for the case-study in consideration of digestion of a meal based on bread and butter. Paracetamol and ketoprofen are considered and analysed in two different protocols. The first one without food (test 1) where the reference drug is injected in the first compartment as an external flow. The second one, with food (test 2), where an initial concentration of nutrients (in this case 150g of bread and 20g of butter) is considered in addition. The model simulation has been validated through pharmacokinetics curves obtained from in vivo test reported in the literature and used to simulate the drug adsorption dynamics in different conditions. The maximum blood concentration was 0.153 mmol/L and 0.0243 mmol/L, respectively for paracetamol and ketoprofen for the test 1. The time to reach the maximum concentration for the paracetamol and ketoprofen is around 55 minutes. In the presence of meal, the drugs show different pharmacokinetics, found qualitatively and quantitatively in agreement with the literature data. The maximum concentration of paracetamol in the blood is 0.100 mmol/L, while it is 0.0135 mmol/L for ketoprofen. The time to reach the maximum concentration is 3 hours and 45 minutes for paracetamol and 3 hours and 35 minutes for ketoprofen. The model was also able to predict experimental points relative to ketoprofen administration with food obtained in vivo.
736
87234
Finite Element Analysis of the Anaconda Device: Efficiently Predicting the Location and Shape of a Deployed Stent
Abstract:
Abdominal Aortic Aneurysm (AAA) is a major life-threatening pathology for which modern approaches reduce the need for open surgery through the use of stenting. The success of stenting though is sometimes jeopardized by the final position of the stent graft inside the human artery which may result in migration, endoleaks or blood flow occlusion. Herein, a finite element (FE) model of the commercial medical device AnacondaTM (Vascutek, Terumo) has been developed and validated in order to create a numerical tool able to provide useful clinical insight before the surgical procedure takes place. The AnacondaTM device consists of a series of NiTi rings sewn onto woven polyester fabric, a structure that despite its column stiffness is flexible enough to be used in very tortuous geometries. For the purposes of this study, a FE model of the device was built in Abaqus® (version 6.13-2) with the combination of beam, shell and surface elements; the choice of these building blocks was made to keep the computational cost to a minimum. The validation of the numerical model was performed by comparing the deployed position of a full stent graft device inside a constructed AAA with a duplicate set-up in Abaqus®. Specifically, an AAA geometry was built in CAD software and included regions of both high and low tortuosity. Subsequently, the CAD model was 3D printed into a transparent aneurysm, and a stent was deployed in the lab following the steps of the clinical procedure. Images on the frontal and sagittal planes of the experiment allowed the comparison with the results of the numerical model. By overlapping the experimental and computational images, the mean and maximum distances between the rings of the two models were measured in the longitudinal, and the transverse direction and, a 5mm upper bound was set as a limit commonly used by clinicians when working with simulations. The two models showed very good agreement of their spatial positioning, especially in the less tortuous regions. As a result, and despite the inherent uncertainties of a surgical procedure, the FE model allows confidence that the final position of the stent graft, when deployed in vivo, can also be predicted with significant accuracy. Moreover, the numerical model run in just a few hours, an encouraging result for applications in the clinical routine. In conclusion, the efficient modelling of a complicated structure which combines thin scaffolding and fabric has been demonstrated to be feasible. Furthermore, the prediction capabilities of the location of each stent ring, as well as the global shape of the graft, has been shown. This can allow surgeons to better plan their procedures and medical device manufacturers to optimize their designs. The current model can further be used as a starting point for patient specific CFD analysis.
735
86145
Design and Development of an Expanded Polytetrafluoroethylene Valved Conduit with Sinus of Valsalva
Abstract:
Babies born with Tetralogy of Fallot, a congenital heart defect, are required to undergo reconstruction surgery to create a valved conduit. As the child matures, the partially reconstructed pulmonary conduit increases in diameter, while the size of the reconstructed valve remains the same. As a result, follow up surgery is required to replace the undersized valve. Thus, in this project, we evaluated the in-vitro performance of a bi-leaflet valve design in terms of percentage regurgitation with increasing artery (conduit) diameters. Results revealed percentage regurgitations ranging from 13% to 34% for conduits tested. It was observed that percentage of regurgitation increased exponentially with increasing diameters. While the amount of regurgitation may seem severe, it is deemed acceptable, and this valve could potentially reduce the frequency of re-operation in the lifetime of pediatric patients.
734
86146
In Vitro Evaluation of an Artificial Venous Valve
Abstract:
Chronic venous insufficiency is a condition where the venous wall or venous valves fail to operate properly. As such, it is difficult for the blood to return from the lower extremities back to the heart. Chronic venous insufficiency affects many people worldwide. In last decade, there have been many new and innovative designs of prosthetic venous valves to replace the malfunction native venous valves. However, thus far, to the authors’ knowledge, there is no successful prosthetic venous valve. In this project, we have developed a venous valve which could operate under low pressure. While further testing is warranted, this unique valve could potentially alleviate problems associated with chronic venous insufficiency.
733
89148
Dynamic Foot Pressure Measurement System Using Optical Sensors
Abstract:
Foot pressure measurement provides necessary information for diagnosis diseases, foot insole design, disorder prevention and other application. In this paper, dynamic foot pressure measurement is presented for pressure measuring with high resolution and accuracy. The dynamic foot pressure measurement system consists of hardware and software system. The hardware system uses a transparent acrylic plate and uses steel as the base. The glossy white paper is placed on the top of the transparent acrylic plate and covering with a black acrylic on the system to block external light. Lighting from LED strip entering around the transparent acrylic plate. The optical sensors, the digital cameras, are underneath the acrylic plate facing upwards. They have connected with software system to process and record foot pressure video in avi file. Visual Studio 2017 is used for software system using OpenCV library.
732
94187
An Intelligent Steerable Drill System for Orthopedic Surgery
Authors:
Abstract:
A steerable and flexible drill is needed in orthopaedic surgery. For example, osteoarthritis is a common condition affecting millions of people for which joint replacement is an effective treatment which improves the quality and duration of life in elderly sufferers. Conventional surgery is not very accurate. Computer navigation and robotics can help increase the accuracy. For example, In Total Hip Arthroplasty (THA), robotic surgery is currently practiced mainly on acetabular side helping cup positioning and orientation. However, femoral stem positioning mostly uses hand-rasping method rather than robots for accurate positioning. The other case for using a flexible drill in surgery is Anterior Cruciate Ligament (ACL) Reconstruction. The majority of ACL Reconstruction failures are primarily caused by technical mistakes and surgical errors resulting from drilling the anatomical bone tunnels required to accommodate the ligament graft. The proposed new steerable drill system will perform orthopedic surgery through curved tunneling leading to better accuracy and patient outcomes. It may reduce intra-operative fractures, dislocations, early failure and leg length discrepancy by making possible a new level of precision. This technology is based on a robotically assisted, steerable, hand-held flexible drill, with a drill-tip tracking device and a multi-modality navigation system. The critical differentiator is that this robotically assisted surgical technology now allows the surgeon to prepare 'patient specific' and more anatomically correct 'curved' bone tunnels during orthopedic surgery rather than drilling straight holes as occurs currently with existing surgical tools. The flexible and steerable drill and its navigation system for femoral milling in total hip arthroplasty had been tested on sawbones to evaluate the accuracy of the positioning and orientation of femoral stem relative to the pre-operative plan. The data show the accuracy of the navigation system is better than traditional hand-rasping method.
731
96073
Patient-Specific Design Optimization of Cardiovascular Grafts
Abstract:
Despite advances in modern surgery, congenital heart disease remains a medical challenge and a major cause of infant mortality. Cardiovascular prostheses are routinely used in surgical procedures to address congenital malformations, for example establishing a pathway from the right ventricle to the pulmonary arteries in pulmonary valvar atresia. Current off-the-shelf options including human and adult products have limited biocompatibility and durability, and their fixed size necessitates multiple subsequent operations to upsize the conduit to match with patients’ growth over their lifetime. Non-physiological blood flow is another major problem, reducing the longevity of these prostheses. These limitations call for better designs that take into account hemodynamical and anatomical characteristics of different patients. We have integrated tissue engineering techniques with modern medical imaging and image processing tools along with mathematical modeling to optimize the design of cardiovascular grafts in a patient-specific manner. Computational Fluid Dynamics (CFD) analysis is done according to models constructed from each individual patient’s data. This allows for improved geometrical design and achieving better hemodynamic performance. Tissue engineering strives to provide a material that grows with the patient and mimic the durability and elasticity of the native tissue. Simulations also give insight on the performance of the tissues produced in our lab and reduce the need for cost and time-consuming methods of evaluation of the grafts. We are also developing a methodology for fabrication of the optimized designs.
730
93272
A Wearable Artificial Blinking Device Providing Mechanical Eyelid Closure for Facial Nerve Paralysis Patients
Abstract:
Bell's palsy is a debilitating condition for which the major symptom is lagophthalmos, an inability to close the eyelid leading to ineffective lubrication of the eye and significant irritation. Methods of providing artificial eyelid closure exist which require invasive surgery, including implantation of gold weights into the upper eyelid. However, the condition generally subsides without intervention within 3-5 months, making surgery highly undesirable. Within this timeframe, there are no temporary treatments that allow for effective lubrication of the eye. A non-surgical method of artificially closing the eyelid was developed using a system of soft exopatches positioned on the eyelid, incorporated into a wearable headset device holding an actuator and sensor. The proposed device would detect muscle activation of the healthy eyelid. This would then activate a mechanical actuator connected to the upper eyelid to physically close the eyelid. The closure mechanism involves lateral linear actuation of a thread in the soft silicone exopatch. The thread passes through the exopatch and is constrained at fixation points on either side of the eyelid. In the open eyelid state, the thread is loose, and no force is applied to the lid. Upon activation of the actuator, displacement is applied, and the thread is tightened. To minimize the length of thread between the two fixation points during tightening, the exopatch moves downwards along with the eyelid, resulting in lid closure. The device was fabricated and tested using silicone cast into 3D printed molds. Full lid closure was demonstrated on a sample user by using the patches and a 20mm stroke linear actuator mounted on a headset. A user interface was then designed to allow for ease of application and removal of the device, as well as better comfort during longer usage periods. A test device was fabricated to demonstrate its utility. The interface was shown to allow for connection of the patches to the actuating element in under 5 seconds. Sensing of the blink impulse prior to eye closure of the healthy hemisphere, to provide closed loop control is proposed. This was investigated using an inexpensive, commercial surface electromyography (sEMG) sensor; however, it suffered from interference from nearby muscle groups. An integrated, wearable device, consisting of the patches, actuator, interface, and sensor was then fabricated and tested. The principles and methods described could lead to the development of a device to provide comfort to sufferers of facial palsy.
729
93907
Evaluation and Fault Classification for Healthcare Robot during Sit-To-Stand Performance through Center of Pressure
Abstract:
Healthcare robot for assisting sit-to-stand (STS) performance had aroused numerous research interests. To author’s best knowledge, knowledge about how evaluating healthcare robot is still unknown. Robot should be labeled as fault if users feel demanding during STS when they are assisted by robot. In this research, we aim to propose a method to evaluate sit-to-stand assist robot through center of pressure (CoP), then classify different STS performance. Experiments were executed five times with ten healthy subjects under four conditions: two self-performed STSs with chair heights of 62 cm and 43 cm, and two robot-assisted STSs with chair heights of 43 cm and robot end-effect speed of 2 s and 5 s. CoP was measured using a Wii Balance Board (WBB). Bayesian classification was utilized to classify STS performance. The results showed that faults occurred when decreased the chair height and slowed robot assist speed. Proposed method for fault classification showed high probability of classifying fault classes form others. It was concluded that faults for STS assist robot could be detected by inspecting center of pressure and be classified through proposed classification algorithm.
728
94041
An Inflatable and Foldable Knee Exosuit Based on Intelligent Management of Biomechanical Energy
Abstract:
Wearable robotics is a potential solution in aiding gait rehabilitation of lower limbs dyskinesia patients, such as knee osteoarthritis or stroke afflicted patients. Many wearable robots have been developed in the form of rigid exoskeletons and soft exosuits, but their bulk devices, high cost and control complexity hinder their popularity in the field of gait rehabilitation. Thus, the development of a portable, compliant and low-cost wearable robot for gait rehabilitation is necessary. Inspired by Chinese traditional folding fans and balloon inflators, the authors present an inflatable, foldable and variable stiffness knee exosuit (IFVSKE) in this paper. The pneumatic actuator of IFVSKE was fabricated in the shape of folding fans by using rubber materials. The geometric and mechanical properties of IFVSKE were characterized with both theoretical and experimental methods. To assist the knee joint smartly, an intelligent control profile for IFVSKE was proposed based on the concept of full-cycle energy management of the biomechanical energy during human movement. The biomechanical energy of knee joints in a walking gait cycle of patients could be collected and released to assist the joint motion just by adjusting the inner pressure of IFVSKE. In preliminary evaluation studies, the authors captured the motion data of a healthy subject walking with and without IFVSKE, and then they analyzed the inverse kinematic and kinetic characteristics of the subject. From the result, a promising reduction was found in knee joint torque of the subject while walking with IFUSKE. The subject also stated that it was energy saving and comfortable to walk with IFVSKE.
727
95222
Noninvasive Evaluation of Acupuncture by Measuring Facial Temperature through Thermal Image
Abstract:
Acupuncture, known as sensory simulation, has been used to treat various disorders for thousands of years. However, present studies had not addressed approaches for noninvasive measurement in order to evaluate therapeutic effect of acupuncture. The purpose of this study is to propose a noninvasive method to evaluate acupuncture by measuring facial temperature through thermal image. Three human subjects were recruited in this study. Each subject received acupuncture therapy for 30 mins. Acupuncture needles (Ø0.16 x 30 mm) were inserted into Baihui point (DU20), Neiguan points (PC6) and Taichong points (LR3), acupuncture needles (Ø0.18 x 39 mm) were inserted into Tanzhong point (RN17), Zusanli points (ST36) and Yinlingquan points (SP9). Facial temperature was recorded by an infrared thermometer. Acupuncture therapeutic effect was compared pre- and post-acupuncture. Experiment results demonstrated that facial temperature changed according to acupuncture therapeutic effect. It was concluded that proposed method showed high potential to evaluate acupuncture by noninvasive measurement of facial temperature.
726
91885
Regulation of an Autophagy Protein Restore Sensitivity of Paclitaxel-Resistant Cells
Abstract:
Paclitaxel (PTX) is a widely-used chemotherapeutic agent for advanced non-small cell lung cancer (NSCLC). However, the emergence of multidrug resistance (MDR) limits the utility of PTX. Herein, a paclitaxel-resistant NCI-H23-TXR subline (an NSCLC cell line) was established by continuous exposure of NCI-H23 cells to PTX, and the distinct expression of autophagy level was observed between NCI-H23-TXR and parental NCI-H23 cells. We found Beclin1 siRNA, an autophagy inhibitor, could restore sensitivity of NCI-H23-TXR cells to PTX. An artificially-made chondroitin sulfate (CS) and polyethylenimine (PEI) was constructed as a vector for delivery and protection of Beclin1 siRNA. The knockdown of autophagy-related Beclin1 gene to restore the sensitivity of drug resistant cells to PTX was associated with the inhibition of the ATP-binding cassette transporters (ABC transporters) efflux proteins. This fact might provide new insight into PTX chemo-resistant therapy in NSCLC.
725
92084
A Time and Frequency Dependent Study of Low Intensity Microwave Radiation Induced Endoplasmic Reticulum Stress and Alteration of Autophagy in Rat Brain
Abstract:
With the tremendous increase in exposure to radiofrequency microwaves emitted by mobile phones, globally public awareness has grown with regard to the potential health hazards of microwaves on the nervous system in the brain. India alone has more than one billion mobile users out of 4.3 billion globally. Our studies have suggested that radio frequency able to affect neuronal alterations in the brain, and hence, affecting cognitive behaviour. However, adverse effect of low-intensity microwave exposure with endoplasmic reticulum stress and autophagy has not been evaluated yet. In this study, we explore whether low-intensity microwave induces endoplasmic reticulum stress and autophagy with varying frequency and time duration in Wistar rat. Ninety-six male Wistar rat were divided into 12 groups of 8 rats each. We studied at 900 MHz, 1800 MHz, and 2450 MHz frequency with reference to sham-exposed group. At the end of the exposure, the rats were sacrificed to collect brain tissue and expression of CHOP, ATF-4, XBP-1, Bcl-2, Bax, LC3 and Atg-4 gene was analysed by real-time PCR. Significant fold change (p < 0.05) of gene expression was found in all groups of 1800 MHz and 2450 MHz exposure group in comparison to sham exposure group. In conclusion, the microwave exposure able to induce ER stress and modulate autophagy. ER (endoplasmic reticulum) stress and autophagy vary with increasing frequency as well as the duration of exposure. Our results suggested that microwave exposure is harmful to neuronal health as it induces ER stress and hampers autophagy in neuron cells and thereby increasing the neuron degeneration which impairs cognitive behaviour of experimental animals.
724
91310
Relationship between Matrix Metalloproteases and Tissue Inhibitor of Matrix Metalloproteinase Levels and Elastic Moduli of Ascending Aneurysms
Abstract:
The objective of this study is to determine if there is a correlation between the biological levels of matrix metalloproteinases and tissue inhibitor of matrix metalloproteinase (TIMP) and the elastic moduli of the ascending aortic wall in patients with ascending thoracic aortic aneurysms (ATAA). Methods: Circumferential specimens from twelve patients with ATAA were obtained from the greater curvature, and their tensile properties (maximum elastic modulus) were tested uniaxially. The levels of MMP2, 3, and 9, as well as TIMP1, were determined in these aortic wall specimens using MMP/TIMP antibodies array. Direct relations were found between MMP2 and the elastic modulus of the ascending aorta wall and between MMP9 and TIMP1.
723
95616
Development of Bioactive and Osteogenic Chain Extender Containing Polyurethanes as Bone Regenerative Films
Abstract:
Bone tissue engineering based approaches and development of new generation hard tissue supports are essential due to the limitations of bone grafts up on bone injury. Bone regenerative films are notable as hard tissue supporting materials, that direct bone tissue formation while preventing soft tissues ingrowth through the damaged area. In this study, polyurethane based bone regenerative films were developed with bioactive agents. Polyurethanes are the most suitable polymer group for the development of bone regenerative films due to their biocompatibility and excellent viscoelastic and mechanical properties. In this current study, a prodrug and inorganic compound as bioactive agents for polyurethane composition were used. Metformin is the most commonly used hyperglycemic bioactive prodrug for treatment of type2 diabetes. It is preferred as a chain extender due to its osteogenic effects on osteoblast differentiation. β-glycerophosphate is an osteoconductive compound having the structure of inorganic phosphate groups as the main component of bone. In this study, biodegradable PU-Metformin and PU-β-glycerophosphate films were synthesized by two-step condensation polymerization of polycaprolactone diol, 1-6-hexamethylene diisocyanate monomers, and bioactive agents. The polymer synthesis parameters; monomer ratio, reaction time and reaction temperature were optimized, and characterization studies were carried to examine the detailed chemistry and molecular weight distribution of polymers. Presence of β-glycerophosphate and metformin changed the chemical and thermal properties of polyurethanes. FTIR examinations showed the integration of bioactive compounds into PU polymer chains through their active functional ends. The presence of β-glycerophosphate lowered the Tg of PU while metformin showed slight increase in Tg as examined by Differential Scanning Calorimetry (DSC). The viscoelastic properties of PU based bone regenerative films were investigated by Dynamic Mechanical Analysis (DMA) in tensile frequencies of 1 Hz and 10 Hz. PU based bone regenerative films had shown viscoelastic regions; glassy plateau, leathery flow, rubbery plateau and viscous flow in storage modulus vs. temperature curves. Also, the thermal stabilities of bone regenerative films were analyzed with Thermal Gravimetric Analysis (TGA). The in vitro biodegradation behavior of bone regenerative films was examined in a hydrolytic, enzymatic and oxidative medium for 75 days period. PU-Met and PU-βGF films showed surface type of erosion and biodegraded around 36 % and 52 % at 21 days, respectively. The presence of bioactive agents improved the elastomeric properties of PUs. β-glycerophosphate and metformin containing PU based bone regenerative films provide promising results for bone tissue engineering applications.
722
95005
Multifunctional Bismuth-Based Nanoparticles as Theranostic Agent for Imaging and Radiation Therapy
Abstract:
In recent years many studies have been focused on bismuth-based nanoparticles as radiosensitizer and contrast agent in radiation therapy and imaging due to the high atomic number (Z = 82), high photoelectric absorption, low cost, and low toxicity. This study aims to introduce a new multifunctional bismuth-based nanoparticle as a theranostic agent for radiotherapy, computed tomography (CT) and magnetic resonance imaging (MRI). We synthesized bismuth ferrite (BFO, BiFeO3) nanoparticles by sol-gel method and surface of the nanoparticles were modified by Polyethylene glycol (PEG). After proved biocompatibility of the nanoparticles, the ability of them as contract agent in Computed tomography (CT) and magnetic resonance imaging (MRI) was investigated. The relaxation time rate (R2) in MRI and Hounsfield unit (HU) in CT imaging were increased with the concentration of the nanoparticles. Moreover, the effect of nanoparticles on dose enhancement in low energy was investigated by clonogenic assay. According to clonogenic assay, sensitizer enhancement ratios (SERs) were obtained as 1.35 and 1.76 for nanoparticle concentrations of 0.05 mg/ml and 0.1 mg/ml, respectively. In conclusion, our experimental results demonstrate that the multifunctional nanoparticles have the ability to employ as multimodal imaging and therapy to enhance theranostic efficacy.
721
77673
Assessment of Arterial Stiffness through Measurement of Magnetic Flux Disturbance and Electrocardiogram Signal
Abstract:
Arterial stiffness predicts mortality and morbidity, independently of other cardiovascular risk factors. And it is a major risk factor for age-related morbidity and mortality. The non-invasive industry gold standard measurement system of arterial stiffness utilizes pulse wave velocity method. However, the desktop device is expensive and requires trained professional to operate. The main objective of this research is the proof of concept of the proposed non-invasive method which uses measurement of magnetic flux disturbance and electrocardiogram (ECG) signal for measuring arterial stiffness. The method could enable accurate and easy self-assessment of arterial stiffness at home, and to help doctors in research, diagnostic and prescription in hospitals and clinics. A platform for assessing arterial stiffness through acquisition and analysis of radial artery pulse waveform and ECG signal has been developed based on the proposed method. Radial artery pulse waveform is acquired using the magnetic based sensing technology, while ECG signal is acquired using two dry contact single arm ECG electrodes. The measurement only requires the participant to wear a wrist strap and an arm band. Participants were recruited for data collection using both the developed platform and the industry gold standard system. The results from both systems underwent correlation assessment analysis. A strong positive correlation between the results of the two systems is observed. This study presents the possibility of developing an accurate, easy to use and affordable measurement device for arterial stiffness assessment.
720
90497
Dynamics of a Susceptible-Infected-Recovered Model along with Time Delay, Modulated Incidence, and Nonlinear Treatment
Abstract:
As we know that, time delay exists almost in every biological phenomenon. Therefore, in the present study, we propose a susceptible–infected–recovered (SIR) epidemic model along with time delay, modulated incidence rate of infection, and Holling Type II nonlinear treatment rate. The present model aims to provide a strategy to control the spread of epidemics. In the mathematical study of the model, it has been shown that the model has two equilibriums which are named as disease-free equilibrium (DFE) and endemic equilibrium (EE). Further, stability analysis of the model is discussed. To prove the stability of the model at DFE, we derived basic reproduction number, denoted by (R₀). With the help of basic reproduction number (R₀), we showed that the model is locally asymptotically stable at DFE when the basic reproduction number (R₀) less than unity and unstable when the basic reproduction number (R₀) is greater than unity. Furthermore, stability analysis of the model at endemic equilibrium has also been discussed. Finally, numerical simulations have been done using MATLAB 2012b to exemplify the theoretical results.
719
91055
Time Delayed Susceptible-Vaccinated-Infected-Recovered-Susceptible Epidemic Model along with Nonlinear Incidence and Nonlinear Treatment
Abstract:
Infectious diseases are a leading cause of death worldwide and hence a great challenge for every nation. Thus, it becomes utmost essential to prevent and reduce the spread of infectious disease among humans. Mathematical models help to better understand the transmission dynamics and spread of infections. For this purpose, in the present article, we have proposed a nonlinear time-delayed SVIRS (Susceptible-Vaccinated-Infected-Recovered-Susceptible) mathematical model with nonlinear type incidence rate and nonlinear type treatment rate. Analytical study of the model shows that model exhibits two types of equilibrium points, namely, disease-free equilibrium and endemic equilibrium. Further, for the long-term behavior of the model, stability of the model is discussed with the help of basic reproduction number R₀ and we showed that disease-free equilibrium is locally asymptotically stable if the basic reproduction number R₀ is less than one and unstable if the basic reproduction number R₀ is greater than one for the time lag τ≥0. Furthermore, when basic reproduction number R₀ is one, using center manifold theory and Casillo-Chavez and Song theorem, we showed that the model undergoes transcritical bifurcation. Moreover, numerical simulations are being carried out using MATLAB 2012b to illustrate the theoretical results.
718
85444
Reconstruction Spectral Reflectance Cube Based on Artificial Neural Network for Multispectral Imaging System
Abstract:
The multispectral imaging (MSI) technique has been used for skin analysis, especially for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel. For ergonomic purpose, our multispectral imaging system is decomposed in two parts: a light source compartment based on LED with 11 different wavelenghts and a monochromatic 8-Bit CCD camera with C-Mount Objective Lens. The software based on GUI MATLAB to control the system was also developed. Our system provides 11 monoband images and is coupled with a software reconstructing hyperspectral cubes from these multispectral images. In this paper, we proposed a new method to build a hyperspectral reflectance cube based on artificial neural network algorithm. After preliminary corrections, a neural network is trained using the 32 natural color from X-Rite Color Checker Passport. The learning procedure involves acquisition, by a spectrophotometer. This neural network is then used to retrieve a megapixel multispectral cube between 380 and 880 nm with a 5 nm resolution from a low-spectral-resolution multispectral acquisition. As hyperspectral cubes contain spectra for each pixel; comparison should be done between the theoretical values from the spectrophotometer and the reconstructed spectrum. To evaluate the performance of reconstruction, we used the Goodness of Fit Coefficient (GFC) and Root Mean Squared Error (RMSE). To validate reconstruction, the set of 8 colour patches reconstructed by our MSI system and the one recorded by the spectrophotometer were compared. The average GFC was 0.9990 (standard deviation = 0.0010) and the average RMSE is 0.2167 (standard deviation = 0.064).