Search results for: scan radiation

Authors: Sireetorn Kuharat, Anwar Beg

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In this study, multi-mode heat transfer characteristics of spacecraft solar collectors are investigated computationally. Two-dimensional steady-state incompressible laminar Newtonian viscous convection-radiative heat transfer in a rectangular solar collector geometry. The ANSYS FLUENT finite volume code (version 17.2) is employed to simulate the thermo-fluid characteristics. Several radiative transfer models are employed which are available in the ANSYS workbench, including the classical Rosseland flux model and the more elegant P1 flux model. Mesh-independence tests are conducted. Validation of the simulations is conducted with a computational Harlow-Welch MAC (Marker and Cell) finite difference method and excellent correlation. The influence of aspect ratio, Prandtl number (Pr), Rayleigh number (Ra) and radiative flux model on temperature, isotherms, velocity, the pressure is evaluated and visualized in color plots. Additionally, the local convective heat flux is computed and solutions are compared with the MAC solver for various buoyancy effects (e.g. Ra = 10,000,000) achieving excellent agreement. The P1 model is shown to better predict the actual influence of solar radiative flux on thermal fluid behavior compared with the limited Rosseland model. With increasing Rayleigh numbers the hot zone emanating from the base of the collector is found to penetrate deeper into the collector and rises symmetrically dividing into two vortex regions with very high buoyancy effect (Ra >100,000). With increasing Prandtl number (three gas cases are examined respectively hydrogen gas mixture, air and ammonia gas) there is also a progressive incursion of the hot zone at the solar collector base higher into the solar collector space and simultaneously a greater asymmetric behavior of the dual isothermal zones. With increasing aspect ratio (wider base relative to the height of the solar collector geometry) there is a greater thermal convection pattern around the whole geometry, higher temperatures and the elimination of the cold upper zone associated with lower aspect ratio.

Keywords: thermal convection, radiative heat transfer, solar collector, Rayleigh number

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Authors: Semyachkina-Glushkovskaya Oxana, Fedosov Ivan, Blokhina Inna, Terskov Andrey, Evsukova Arina, Elovenko Daria, Adushkina Viktoria, Dubrovsky Alexander, Jürgen Kurths

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In modern neurobiology, sleep is considered a novel biomarker and a promising therapeutic target for brain diseases. This is due to recent discoveries of the nighttime activation of the brain lymphatic system (BLS), playing an important role in the removal of wastes and toxins from the brain and contributes neuroprotection of the central nervous system (CNS). In our review, we discuss that night stimulation of BLS might be a breakthrough strategy in a new treatment of Alzheimer’s and Parkinson’s disease, stroke, brain trauma, and oncology. Although this research is in its infancy, however, there are pioneering and promising results suggesting that night transcranial photostimulation (tPBM) stimulates more effectively lymphatic removal of amyloid-beta from mouse brain than daily tPBM that is associated with a greater improvement of the neurological status and recognition memory of animals. In our previous study, we discovered that tPBM modulates the tone and permeability of the lymphatic endothelium by stimulating NO formation, promoting lymphatic clearance of wastes and toxins from the brain tissues. We also demonstrate that tPBM can also lead to angio- and lymphangiogenesis, which is another mechanism underlying tPBM-mediated stimulation of BLS. Thus, photo-augmentation of BLS might be a promising therapeutic target for preventing or delaying brain diseases associated with BLS dysfunction. Here we present pioneering technology for simultaneous tPBM in humans and sleep monitoring for stimulation of BLS to remove toxins from CNS and modulation of brain immunity. The wireless-controlled gadget includes a flexible organic light-emitting diode (LED) source that is controlled directly by a sleep-tracking device via a mobile application. The designed autonomous LED source is capable of providing the required therapeutic dose of light radiation at a certain region of the patient’s head without disturbing of sleeping patient. To minimize patients' discomfort, advanced materials like flexible organic LEDs were used. Acknowledgment: This study was supported by RSF project No. 23-75-30001.

Keywords: brain diseases, brain lymphatic system, phototherapy, sleep

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Authors: Moin Uddin, M. Masroor A. Khan, Faisal Rasheed, Tariq Ahmad Dar, Akbar Ali, Lalit Varshney

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Oligomers, obtained by exposing the natural polysaccharides (alginate, carrageenan, chitosan, etc.) to cobalt-60 generated gamma radiation may prove as potent plant growth promoters when applied as foliar sprays to the plants. They function as endogenous growth elicitors, triggering the synthesis of different enzymes and modulating various plant responses by exploiting the gene expression. Exogenous application of Jasmonic acid or of its methyl ester, methyl jasmonate (MeJ) has been reported to increase the secondary metabolites production in medicinal and aromatic plants. Keeping this in mind, three pot experiments were conducted to test whether the foliar application of irradiated-chitosan (IC) and MeJ, applied alone or in combination, could augment the active constituents as well as growth, physiological and yield attributes of Catharanthus roseus, which carries anticancer alkaloids, viz. vincristine and vinblastine, in its leaves in addition to various other useful alkaloids. Totally, 5 spray treatments, comprising various aqueous solutions of IC [20, 40, 80 and 160 mg L-1 (Experiment 1)], MeJ (10, 20, 30 and 40 mg L-1 (Experiment 2)] and those of IC+MeJ [40+20, 40+30, 80+20, 80+30, 160+20 and 160+30 mg L-1 (Experiment 3)], were applied at seven days interval. Total leaf-alkaloids content as well as growth, physiological and yield parameters, evaluated at 120 days after sowing, were significantly enhanced by IC application. IC application could not increase the leaf-content of vincristine and vinblastine; nonetheless, it significantly augmented the yield of these alkaloids owing to enhancing the dry mass of leaves per plant. MeJ application, particularly at 30 mg L-1, increased both content (17%) and yield (48%) of total leaf-alkaloids as well as the content and yield of vincristine ( 29 and 63%, respectively) and vinblastine (14 and 44%, respectively) alkaloids, though it significantly decreased most other parameters studied, particularly at higher concentrations (30 and 40 mg L-1 of MeJ). As compared to the control (water-spray treatment), collective application of IC (80 mg L-1) and MeJ (20 mg L-1) resulted in the highest values of most of the parameters studied. However, 80 mg L-1 of IC applied with 30 mg L-1 of MeJ gave the best results for the content and yield of total as well as anticancer leaf-alkaloids (vincristine and vinblastine). Comparing the control, it increased the content and yield of total leaf-alkaloids (37 and 118%, respectively) and those of vincristine (65 and 163%, respectively) and vinblastine (31 and 107%, respectively). Conclusively, the applied technique significantly enhanced the production of total as well as anticancer alkaloids of Catharanthus roseus.

Keywords: anticancer alkaloids (vincristine and vinblastine), catharanthus roseus, irradiated chitosan, methyl jasmonate

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Authors: Raoudane Bouziyan, Kawser Mohammad Tawhid

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Microstrip antennas are low in profile, light in weight, conformable in structure and are now developed for many applications. The main difficulty of the microstrip antenna is its narrow bandwidth. Several modern applications like satellite communications, remote sensing, and multi-function radar systems will find it useful if there is dual-band antenna operating from a single aperture. Some applications require covering both transmitting and receiving frequency bands which are spaced apart. Providing multiple antennas to handle multiple frequencies and polarizations becomes especially difficult if the available space is limited as with airborne platforms and submarine periscopes. Dual band operation can be realized from a single feed using slot loaded or stacked microstrip antenna or two separately fed antennas sharing a common aperture. The former design, when used in arrays, has certain limitations like complicated beam forming or diplexing network and difficulty to realize good radiation patterns at both the bands. The second technique provides more flexibility with separate feed system as beams in each frequency band can be controlled independently. Another desirable feature of a dual band antenna is easy adjustability of upper and lower frequency bands. This thesis presents investigation of a new dual-band antenna, which is a hybrid of microstrip and waveguide radiating elements. The low band radiator is a Shorted Annular Ring (SAR) microstrip antenna and the high band radiator is an aperture antenna. The hybrid antenna is realized by forming a waveguide radiator in the shorted region of the SAR microstrip antenna. It is shown that the upper to lower frequency ratio can be controlled by the proper choice of various dimensions and dielectric material. Operation in both linear and circular polarization is possible in either band. Moreover, both broadside and conical beams can be generated in either band from this antenna element. Finite Element Method based software, HFSS and Method of Moments based software, FEKO were employed to perform parametric studies of the proposed dual-band antenna. The antenna was not tested physically. Therefore, in most cases, both HFSS and FEKO were employed to corroborate the simulation results.

Keywords: FEKO, HFSS, dual band, shorted annular ring patch

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Authors: Florian Keipert, Hagen Schmitd

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The size selective separation of different species in a microfluidic system is an actual task in biological or medical research. Former works dealt with the utilisation of the acoustic radiation force (ARF) caused by a plane travelling Surface Acoustic Wave (tSAW). In literature the ARF is described by a dimensionless parameter κ, depending on the wavelength and the particle diameter. To our knowledge research was done for values 0.2 < κ < 5.8 showing that the ARF is dominating the acoustic streaming force (ASF) for κ > 1.2. As a consequence the particle separation is limited by κ. In addition the dependence on the electrical power level was examined but only for κ > 1 pointing out an increased particle deflection for higher electrical power levels. Nevertheless a detailed study on the ASF and ARF especially for κ < 1 is still missing. In our setup we used a tSAW with a wavelength λ = 90 µm and 3 µm PS particles corresponding to κ = 0.3. Herewith the influence of the applied electrical power level on the particle deflection in a polydimethylsiloxan micro channel was investigated. Our results show an increased particle deflection for an increased electrical power level, which coincides with the reported results for κ > 1. Therefore particle separation is in contrast to literature also possible for lower κ values. Thereby the experimental setup can be generally simplified by a coordinated electrical power level for the specific particle size. Furthermore this raises the question of whether this particle deflection is caused only by the ARF as adopted so far or by the ASF or the sum of both forces. To investigate this fact a 0% - 24% saline solution was used and thus the mismatch between the compressibility of the PS particle and the working fluid could be changed. Therefore it is possible to change the relative strength between ARF and ASF and consequently the particle deflection. We observed a decreasing in the particle deflection for an increased NaCl content up to a 12% saline solution and subsequently an increasing of the particle deflection. Our observation could be explained by the acoustic contrast factor Φ, which depends on the compressibility mismatch. The compressibility of water is increased by the NaCl and the range of a 0% - 24% saline solution covers the PS particle compressibility. Hence the particle deflection reaches a minimum value for the accordance between compressibility of PS particle and saline solution. This minimum value can be estimated as the particle deflection only caused by the ASF. Knowing the particle deflection due to the ASF the particle deflection caused by the ARF can be calculated and thus finally the relation between both forces. Concluding, the particle deflection and therefore the size selective particle separation generated by a tSAW can be achieved for values κ < 1, simplifying actual setups by adjusting the electrical power level. Beyond we studied for the first time the relative strength between ARF and ASF to characterise the particle deflection in a microchannel.

Keywords: ARF, ASF, particle separation, saline solution, tSAW

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Authors: Nnodi Chinweikpe Akelachi, Adebayo Oladini Kachollom Ifeoma

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Insecurity and the possession of nuclear weapons for non-peaceful purposes constitute a major threat to global peace and security, and this undermines the capacity for sustainable development. In Nigeria, the threat of terrorism is a challenge to national stability. For over a decade, Nigeria has been faced with insecurity ranging from Boko-Haram terrorist groups, kidnapping and banditry. The threat exhibited by this non-state actor poses a huge challenge to nuclear and radiological high risks facilities in Nigeria. This challenge has resulted in the regulatory authority and International stakeholders formulating policies for a good mitigation strategy. This strategy is enshrined in formulated laws, regulations and guides like the repealed Nuclear Safety and Radiation Protection Act 19 of 1995 (Nuclear safety, Physical Security and Safeguards Bill), the Nigerian Physical Protection of Nuclear Material and Nuclear Facilities, and Nigerian Nuclear Safeguards Regulations of 2021. All this will help Nigeria’s effort to meet its national nuclear security and safeguards obligations. To further enhance the implementation of nuclear security and safeguards system, Nigeria has signed the Non-Proliferation Treaty (NPT) in 1970, the Comprehensive Safeguards Agreement (INFCIRC/358) in 1988, Additional Protocol in 2007 as well as the Convention on Physical Protection of Nuclear Material and its amendment in 2005. In view of the evolving threats by non-state actors in Nigeria, physical protection security upgrades are being implemented in nuclear and all high-risk radiological facilities through the support of the United States Department of Energy (US-DOE). Also, the IAEA has helped strengthen nuclear security and safeguard systems through the provision of technical assistance and capacity development. Efforts are being made to address some of the challenges identified in the cause of implementing the measures for effective nuclear security and safeguards systems in Nigeria. However, there are eminent challenges in the implementation of the measures within the security and systems in Nigeria. These challenges need to be addressed for an effective security and safeguard regime in Nigeria. This paper seeks to address the challenges encountered in implementing the regulatory and stakeholder measures for effective security and safeguards regime in Nigeria, amongst others.

Keywords: nuclear regulatory body, nuclear facilities and activities, international stakeholders, security and safeguards measures

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Authors: Sudeshna Chandra, Christian Gäbler, Christian Schliebe, Heinrich Lang

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Highly branched dendrimers provide structural homogeneity, controlled composition, comparable size to biomolecules, internal porosity and multiple functional groups for conjugating reactions. Electro-active dendrimers containing multiple redox units have generated great interest in their use as electrode modifiers for development of biosensors. The electron transfer between the redox-active dendrimers and the biomolecules play a key role in developing a biosensor. Ferrocenes have multiple and electrochemically equivalent redox units that can act as electron “pool” in a system. The ferrocenyl-terminated polyamidoamine dendrimer is capable of transferring multiple numbers of electrons under the same applied potential. Therefore, they can be used for dual purposes: one in building a film over the electrode for immunosensors and the other for immobilizing biomolecules for sensing. Electrochemical immunosensor, thus developed, exhibit fast and sensitive analysis, inexpensive and involve no prior sample pre-treatment. Electrochemical amperometric immunosensors are even more promising because they can achieve a very low detection limit with high sensitivity. Detection of the cancer biomarkers at an early stage can provide crucial information for foundational research of life science, clinical diagnosis and prevention of disease. Elevated concentration of biomarkers in body fluid is an early indication of some type of cancerous disease and among all the biomarkers, IgG is the most common and extensively used clinical cancer biomarkers. We present an IgG (=immunoglobulin) electrochemical immunosensor using a newly synthesized redox-active ferrocenyl dendrimer of generation 2 (G2Fc) as glassy carbon electrode material for immobilizing the antibody. The electrochemical performance of the modified electrodes was assessed in both aqueous and non-aqueous media using varying scan rates to elucidate the reaction mechanism. The potential shift was found to be higher in an aqueous electrolyte due to presence of more H-bond which reduced the electrostatic attraction within the amido groups of the dendrimers. The cyclic voltammetric studies of the G2Fc-modified GCE in 0.1 M PBS solution of pH 7.2 showed a pair of well-defined redox peaks. The peak current decreased significantly with the immobilization of the anti-goat IgG. After the immunosensor is blocked with BSA, a further decrease in the peak current was observed due to the attachment of the protein BSA to the immunosensor. A significant decrease in the current signal of the BSA/anti-IgG/G2Fc/GCE was observed upon immobilizing IgG which may be due to the formation of immune-conjugates that blocks the tunneling of mass and electron transfer. The current signal was found to be directly related to the amount of IgG captured on the electrode surface. With increase in the concentration of IgG, there is a formation of an increasing amount of immune-conjugates that decreased the peak current. The incubation time and concentration of the antibody was optimized for better analytical performance of the immunosensor. The developed amperometric immunosensor is sensitive to IgG concentration as low as 2 ng/mL. Tailoring of redox-active dendrimers provides enhanced electroactivity to the system and enlarges the sensor surface for binding the antibodies. It may be assumed that both electron transfer and diffusion contribute to the signal transformation between the dendrimers and the antibody.

Keywords: ferrocenyl dendrimers, electrochemical immunosensors, immunoglobulin, amperometry

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Authors: Piotr Wadolowski, Grzegorz Krzesinski, Piotr Gutowski

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The aim of the presented work is to recognize the impact of mini-plate application approach on the stress and displacement within the stabilization devices and surrounding bones. The mini-plate osteosynthesis technique is widely used by craniofacial surgeons as an improved replacement of wire connection approach. Many different types of metal plates and screws are used to the physical connection of fractured bones. Below investigation is based on a clinical observation of patient hospitalized with mini-plate stabilization system. Analysis was conducted on a solid mandible geometry, which was modeled basis on the computed tomography scan of the hospitalized patient. In order to achieve most realistic connected system behavior, the cortical and cancellous bone layers were assumed. The temporomandibular joint was simplified to the elastic element to allow physiological movement of loaded bone. The muscles of mastication system were reduced to three pairs, modeled as shell structures. Finite element grid was created by the ANSYS software, where hexahedral and tetrahedral variants of SOLID185 element were used. A set of nonlinear contact conditions were applied on connecting devices and bone common surfaces. Properties of particular contact pair depend on screw - mini-plate connection type and possible gaps between fractured bone around osteosynthesis region. Some of the investigated cases contain prestress introduced to the mini-plate during the application, what responds the initial bending of the connecting device to fit the retromolar fossa region. Assumed bone fracture occurs within the mandible angle zone. Due to the significant deformation of the connecting plate in some of the assembly cases the elastic-plastic model of titanium alloy was assumed. The bone tissues were covered by the orthotropic material. As a loading were used the gauge force of magnitude of 100N applied in three different locations. Conducted analysis shows significant impact of mini-plate application methodology on the stress distribution within the miniplate. Prestress effect introduces additional loading, which leads to locally exceed the titanium alloy yield limit. Stress in surrounding bone increases rapidly around the screws application region, exceeding assumed bone yield limit, what indicate the local bone destruction. Approach with the doubled mini-plate shows increased stress within the connector due to the too rigid connection, where the main path of loading leads through the mini-plates instead of plates and connected bones. Clinical observations confirm more frequent plate destruction of stiffer connections. Some of them could be an effect of decreased low cyclic fatigue capability caused by the overloading. The executed analysis prove that the mini-plate system provides sufficient support to mandible fracture treatment, however, many applicable solutions shifts the entire system to the allowable material limits. The results show that connector application with the initial loading needs to be carefully established due to the small material capability tolerances. Comparison to the clinical observations allows optimizing entire connection to prevent future incidents.

Keywords: mandible fracture, mini-plate connection, numerical analysis, osteosynthesis

Procedia PDF Downloads 249

Authors: Ajit Brindhaban

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Background and Purpose: Computed Tomography (CT) scans have become the largest source of radiation in radiological imaging. The purpose of this study was to compare the quality of pediatric Computed Tomography (CT) images reconstructed using Filtered Back Projection (FBP) with images reconstructed using different strengths of Iterative Reconstruction (IR) technique, and to perform a feasibility study to assess the use of IR techniques as a dose reduction tool. Materials and Methods: An anthropomorphic phantom representing a 5-year old child was scanned, in two stages, using a Siemens Somatom CT unit. In stage one, scans of the head, chest and abdomen were performed using standard protocols recommended by the scanner manufacturer. Images were reconstructed using FBP and 5 different strengths of IR. Contrast-to-Noise Ratios (CNR) were calculated from average CT number and its standard deviation measured in regions of interest created in the lungs, bone, and soft tissues regions of the phantom. Paired t-test and the one-way ANOVA were used to compare the CNR from FBP images with IR images, at p = 0.05 level. The lowest strength value of IR that produced the highest CNR was identified. In the second stage, scans of the head was performed with decreased mA(s) values relative to the increase in CNR compared to the standard FBP protocol. CNR values were compared in this stage using Paired t-test at p = 0.05 level. Results: Images reconstructed using IR technique had higher CNR values (p < 0.01.) in all regions compared to the FBP images, at all strengths of IR. The CNR increased with increasing IR strength of up to 3, in the head and chest images. Increases beyond this strength were insignificant. In abdomen images, CNR continued to increase up to strength 5. The results also indicated that, IR techniques improve CNR by a up to factor of 1.5. Based on the CNR values at strength 3 of IR images and CNR values of FBP images, a reduction in mA(s) of about 20% was identified. The images of the head acquired at 20% reduced mA(s) and reconstructed using IR at strength 3, had similar CNR as FBP images at standard mA(s). In the head scans of the phantom used in this study, it was demonstrated that similar CNR can be achieved even when the mA(s) is reduced by about 20% if IR technique with strength of 3 is used for reconstruction. Conclusions: The IR technique produced better image quality at all strengths of IR in comparison to FBP. IR technique can provide approximately 20% dose reduction in pediatric head CT while maintaining the same image quality as FBP technique.

Keywords: filtered back projection, image quality, iterative reconstruction, pediatric computed tomography imaging

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Authors: Venkat Kamavaram, Ravi Pare

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Modern warfighters experience extreme environmental conditions in many of their operational and training activities. In temperatures exceeding 95°F, the body’s temperature regulation can no longer cool through convection and radiation. In this case, the only cooling mechanism is evaporation. However, evaporative cooling is often compromised by excessive humidity. Natural cooling mechanisms can be further compromised by clothing and protective gear, which trap hot air and moisture close to the body. Creating an efficient heat extraction apparel system that is also lightweight without hindering dexterity or mobility of personnel working in extreme temperatures is a difficult technical challenge and one that needs to be addressed to increase the probability for the future success of the US military. To address this challenge, Oceanit Laboratories, Inc. has developed and patented a Liquid Cooled Garment (LCG) more effective than any on the market today. Oceanit’s LCG is a form-fitting garment with a network of thermally conductive tubes that extracts body heat and can be worn under all authorized and chemical/biological protective clothing. Oceanit specifically designed and developed ThermoCore®, a thermally conductive polymer, for use in this apparel, optimizing the product for thermal conductivity, mechanical properties, manufacturability, and performance temperatures. Thermal Manikin tests were conducted in accordance with the ASTM test method, ASTM F2371, Standard Test Method for Measuring the Heat Removal Rate of Personal Cooling Systems Using a Sweating Heated Manikin, in an environmental chamber using a 20-zone sweating thermal manikin. Manikin test results have shown that Oceanit’s LCG provides significantly higher heat extraction under the same environmental conditions than the currently fielded Environmental Control Vest (ECV) while at the same time reducing the weight. Oceanit’s LCG vests performed nearly 30% better in extracting body heat while weighing 15% less than the ECV. There are NO cooling garments in the market that provide the same thermal extraction performance, form-factor, and reduced weight as Oceanit’s LCG. The two cooling garments that are commercially available and most commonly used are the Environmental Control Vest (ECV) and the Microclimate Cooling Garment (MCG).

Keywords: thermally conductive composite, tubing, garment design, form fitting vest, thermocore

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Authors: Alexandra Tucaliuc, Alexandra C. Blaga, Anca I. Galaction, Lenuta Kloetzer, Dan Cascaval

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Ergosterol (ergosta-5,7,22-trien-3β-ol), also known as provitamin D2, is the precursor of vitamin D2 (ergocalciferol), because it is converted under UV radiation to this vitamin. The natural sources of ergosterol are mainly the yeasts (Saccharomyces sp., Candida sp.), but it can be also found in fungus (Claviceps sp.) or plants (orchids). In the yeasts cells, ergosterol is accumulated in membranes, especially in free form in the plasma membrane, but also as esters with fatty acids in membrane lipids. The chemical synthesis of ergosterol does not represent an efficient method for its production, in these circumstances, the most attractive alternative for producing ergosterol at larger-scale remains the aerobic fermentation using S. cerevisiae on glucose or by-products from agriculture of food industry as substrates, in batch or fed-batch operating systems. The aim of this work is to analyze comparatively the influence of aeration efficiency on ergosterol production by S. cerevisiae in batch and fed-batch fermentations, by considering different levels of mixing intensity, aeration rate, and n-dodecane concentration. The effects of the studied factors are quantitatively described by means of the mathematical correlations proposed for each of the two fermentation systems, valid both for the absence and presence of oxygen-vector inside the broth. The experiments were carried out in a laboratory stirred bioreactor, provided with computer-controlled and recorded parameters. n-Dodecane was used as oxygen-vector and the ergosterol content inside the yeasts cells has been considered at the fermentation moment related to the maximum concentration of ergosterol, 9 hrs for batch process and 20 hrs for fed-batch one. Ergosterol biosynthesis is strongly dependent on the dissolved oxygen concentration. The hydrocarbon concentration exhibits a significant influence on ergosterol production mainly by accelerating the oxygen transfer rate. Regardless of n-dodecane addition, by maintaining the glucose concentration at a constant level in the fed-batch process, the amount of ergosterol accumulated into the yeasts cells has been almost tripled. In the presence of hydrocarbon, the ergosterol concentration increased by over 50%. The value of oxygen-vector concentration corresponding to the maximum level of ergosterol depends mainly on biomass concentration, due to its negative influences on broth viscosity and interfacial phenomena of air bubbles blockage through the adsorption of hydrocarbon droplets–yeast cells associations. Therefore, for the batch process, the maximum ergosterol amount was reached for 5% vol. n-dodecane, while for the fed-batch process for 10% vol. hydrocarbon.

Keywords: bioreactors, ergosterol, fermentation, oxygen-vector

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Authors: Shunyi Yang, Jingjing Yan, Siyu Dong, Xiangguo Cui

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Current architectural façade design practices incorporate various daylighting and solar radiation analysis methods. These emphasize the impact of geometry on façade design. There is scope to extend this knowledge into methods that address material translucency, porosity, and form. Such approaches can also achieve these conditions through adaptive robotic manufacturing approaches that exploit material dynamics within the design, and alleviate fabrication waste from molds, ultimately accelerating the autonomous manufacturing system. Besides analyzing the environmental solar radiant in building facade design, there is also a vacancy research area of how lighting effects can be precisely controlled by engaging the instant real-time data-driven robot control and manipulating the material properties. Ceramics carries a wide range of transmittance and deformation potentials for robotics control with the research of its material property. This paper presents one semi-autonomous system that engages with real-time data-driven robotics control, hardware kit design, environmental building studies, human interaction, and exploratory research and experiments. Our objectives are to investigate the relationship between different clay bodies or ceramics’ physio-material properties and their transmittance; to explore the feedback system of instant lighting data in robotic fabrication to achieve precise lighting effect; to design the sufficient end effector and robot behaviors for different stages of deformation. We experiment with architectural clay, as the material of the façade that is potentially translucent at a certain stage can respond to light. Studying the relationship between form, material properties, and porosity can help create different interior and exterior light effects and provide façade solutions for specific architectural functions. The key idea is to maximize the utilization of in-progress robotics fabrication and ceramics materiality to create a highly integrated autonomous system for lighting facade design and manufacture.

Keywords: light transmittance, data-driven fabrication, computational design, computer vision, gamification for manufacturing

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Authors: J. Tirano, H. Zea, C. Luhrs

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It is well known that titanium dioxide is a semiconductor with several applications in photocatalytic process. Its band gap makes it very interesting in the photoelectrodes manufacturing used in photoelectrochemical cells for hydrogen production, a clean and environmentally friendly fuel. The synthesis of 1D titanium dioxide nanostructures, such as nanotubes, makes possible to produce more efficient photoelectrodes for solar energy to hydrogen conversion. In essence, this is because it increases the charge transport rate, decreasing recombination options. However, its principal constraint is to be mainly sensitive to UV range, which represents a very low percentage of solar radiation that reaches earth's surface. One of the alternatives to modifying the TiO2’s band gap and improving its photoactivity under visible light irradiation is to dope the nanotubes with transition metals. This option requires fabricating efficient nanostructured photoelectrodes with controlled morphology and specific properties able to offer a suitable surface area for metallic doping. Hence, currently one of the central challenges in photoelectrochemical cells is the construction of nanomaterials with a proper band position for driving the reaction while absorbing energy over the VIS spectrum. This research focuses on the synthesis and characterization of Nidoped TiO2 nanotubes for improving its photocatalytic activity in solar energy conversion applications. Initially, titanium dioxide nanotubes (TNTs) with controlled morphology were synthesized by two-step potentiostatic anodization of titanium foil. The anodization was carried out at room temperature in an electrolyte composed of ammonium fluoride, deionized water and ethylene glycol. Consequent thermal annealing of as-prepared TNTs was conducted in the air between 450 °C - 550 °C. Afterwards, the nanotubes were superficially modified by nickel deposition. Morphology and crystalline phase of the samples were carried out by SEM, EDS and XRD analysis before and after nickel deposition. Determining the photoelectrochemical performance of photoelectrodes is based on typical electrochemical characterization techniques. Also, the morphological characterization associated electrochemical behavior analysis were discussed to establish the effect of nickel nanoparticles modification on the TiO2 nanotubes. The methodology proposed in this research allows using other transition metal for nanotube surface modification.

Keywords: dimensionally stable electrode, nickel nanoparticles, photo-electrode, TiO₂ nanotubes

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Authors: Ursula D. C. Resende, Yan G. Santos, Lucas M. de O. Andrade

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The recent and fast development of the internet, wireless, telecommunication technologies and low-power electronic devices has led to an expressive amount of electromagnetic energy available in the environment and the smart applications technology expansion. These applications have been used in the Internet of Things devices, 4G and 5G solutions. The main feature of this technology is the use of the wireless sensor. Although these sensors are low-power loads, their use imposes huge challenges in terms of an efficient and reliable way for power supply in order to avoid the traditional battery. The radio frequency based energy harvesting technology is especially suitable to wireless power sensors by using a rectenna since it can be completely integrated into the distributed hosting sensors structure, reducing its cost, maintenance and environmental impact. The rectenna is an equipment composed of an antenna and a rectifier circuit. The antenna function is to collect as much radio frequency radiation as possible and transfer it to the rectifier, which is a nonlinear circuit, that converts the very low input radio frequency energy into direct current voltage. In this work, a set of rectennas, mounted on a paper substrate, which can be used for the inner coating of buildings and simultaneously harvest electromagnetic energy from the environment, is proposed. Each proposed individual rectenna is composed of a 2.45 GHz patch antenna and a voltage doubler rectifier circuit, built in the same paper substrate. The antenna contains a rectangular radiator element and a microstrip transmission line that was projected and optimized by using the Computer Simulation Software (CST) in order to obtain values of S11 parameter below -10 dB in 2.45 GHz. In order to increase the amount of harvested power, eight individual rectennas, incorporating metamaterial cells, were connected in parallel forming a system, denominated Electromagnetic Wall (EW). In order to evaluate the EW performance, it was positioned at a variable distance from the internet router, and a 27 kΩ resistive load was fed. The results obtained showed that if more than one rectenna is associated in parallel, enough power level can be achieved in order to feed very low consumption sensors. The 0.12 m2 EW proposed in this work was able to harvest 0.6 mW from the environment. It also observed that the use of metamaterial structures provide an expressive growth in the amount of electromagnetic energy harvested, which was increased from 0. 2mW to 0.6 mW.

Keywords: electromagnetic energy harvesting, metamaterial, rectenna, rectifier circuit

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Authors: Su Chul Han, Seungwoo Park

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As the increasing incidence of cancer, the technology and modality of radiotherapy have advanced and the importance of preclinical model is increasing in the cancer research. Furthermore, the small animal dosimetry is an essential part of the evaluation of the relationship between the absorbed dose in preclinical small animal and biological effect in preclinical study. In this study, we carried out realistic modeling of the preclinical small animal phantom possible to verify irradiated dose using commercial software. The small animal phantom was modeling from 4D Digital Mouse whole body phantom. To manipulate Moby phantom in commercial software (Mimics, Materialise, Leuven, Belgium), we converted Moby phantom to DICOM image file of CT by Matlab and two- dimensional of CT images were converted to the three-dimensional image and it is possible to segment and crop CT image in Sagittal, Coronal and axial view). The CT images of small animals were modeling following process. Based on the profile line value, the thresholding was carried out to make a mask that was connection of all the regions of the equal threshold range. Using thresholding method, we segmented into three part (bone, body (tissue). lung), to separate neighboring pixels between lung and body (tissue), we used region growing function of Mimics software. We acquired 3D object by 3D calculation in the segmented images. The generated 3D object was smoothing by remeshing operation and smoothing operation factor was 0.4, iteration value was 5. The edge mode was selected to perform triangle reduction. The parameters were that tolerance (0.1mm), edge angle (15 degrees) and the number of iteration (5). The image processing 3D object file was converted to an STL file to output with 3D printer. We modified 3D small animal file using 3- Matic research (Materialise, Leuven, Belgium) to make space for radiation dosimetry chips. We acquired 3D object of realistic small animal phantom. The width of small animal phantom was 2.631 cm, thickness was 2.361 cm, and length was 10.817. Mimics software supported efficiency about 3D object generation and usability of conversion to STL file for user. The development of small preclinical animal phantom would increase reliability of verification of absorbed dose in small animal for preclinical study.

Keywords: mimics, preclinical small animal, segmentation, 3D printer

Procedia PDF Downloads 343

Authors: Kamal Kumar Gupta

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The present research work was carried out on Dysdercus koenigii to understand various aspects of reproductive behavior such as mate finding and recognition, mate selection and mating preference, mating receptivity, and prolonged copulation. The studies carried out on mate searching and courtship behaviour of Dysdercus reflected the courtship behaviour in Dysdercus was brief. The opposite sexes are brought together by the pheromone. The males responded to female sex pheromones by showing directional movements toward the sex partners. Change in mating receptivity pattern of female Dysdercus was ascertained using three parameters of mating behaviour i.e. numbers of male’s encounter, the time taken to mate successfully and per cent females responding to mating. It was seen that a receptive female responded positively to the courting males and a high percentage of females mate usually in a very short time span. The females of Dysdercus showed continued mating receptivity throughout their life. The studies pertaining to mate selection by females showed that females generally do not discriminate among males and usually mate with any male they encountered first. The adults of Dysdercus remain in continuous copula up to 72hr. and mate 5-7 time in their life span. Studies pertaining to significance of prolonged mating in the life time reproductive success of the female Dysdercus indicated that fecundity and fertility and oviposition behavior of the female Dysdercus was related to duration of mating. In order to understand sperm precedence, the sterilized males were produced by exposing them to Gamma radiation. Our studies indicated that a dose of 50 Gy of Gamma radiations induced 95% sterility but does not impair the mating behaviour drastically. To understand role of sperms which were transfer during second mating in fertilizing the subsequent egg batches the sperm utilization pattern of doubly mated female was assessed. The females were mated with normal male or sterilized male in a combination. The sperm utilization pattern was determined by P2 value, our studies indicated a very high P2 value of 0.966, and indicated that sperms of last mating were utilized by the female for fertilization. In light of some of the unique reproductive behaviour of Dysdercus koenigii, such as brief courtship behavior, generalized mate selection by the female, continued mating receptivity and a prolonged pre oviposition period, the present studies on sperm precedence provides an explanation to an unusually prolonged copulation in Dysdercus.

Keywords: dysdercus koenigii, mating behaviour, reproductive performance, entomology

Procedia PDF Downloads 318

Authors: Ali Baker, Russel Krawitz

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This paper describes a rare occurrence where a potentially fatal complication of COVID-19 infection (MIS-A) was misdiagnosed as an acute abdomen. As most patients with this syndrome present with fever and gastrointestinal symptoms, they may inadvertently fall under the care of the surgical unit. However, unusual imaging findings and a poor response to anti-microbial therapy should prompt clinicians to suspect a non-surgical etiology. More than half of MIS-A patients require ICU admission and vasopressor support. Prompt referral to a physician is key, as the cornerstone of treatment is IVIG and corticosteroid therapy. A 32 year old woman presented with right sided abdominal pain and fevers. She had also contracted COVID-19 two months earlier. Abdominal examination revealed generalised right sided tenderness. The patient had raised inflammatory markers, but other blood tests were unremarkable. CT scan revealed extensive lymphadenopathy along the ileocolic chain. The patient proved to be a diagnostic dilemma. She was reviewed by several surgical consultants and discussed with several inpatient teams. Although IV antibiotics were commenced, the right sided abdominal pain, and fevers persisted. Pan-culture returned negative. A mild cholestatic derangement developed. On day 5, the patient underwent preparation for colonoscopy to assess for a potential intraluminal etiology. The following day, the patient developed sinus tachycardia and hypotension that was refractory to fluid resuscitation. That patient was transferred to ICU and required vasopressor support. Repeat CT showed peri-portal edema and a thickened gallbladder wall. On re-examination, the patient was Murphy’s sign positive. Biliary ultrasound was equivocal for cholecystitis. The patient was planned for diagnostic laparoscopy. The following morning, a marked rise in cardiac troponin was discovered, and a follow-up echocardiogram revealed moderate to severe global systolic dysfunction. The impression was post-COVID MIS with myocardial involvement. IVIG and Methylprednisolone infusions were commenced. The patient had a great response. Vasopressor support was weaned, and the patient was discharged from ICU. The patient continued to improve clinically with oral prednisolone, and was discharged on day 17. Although MIS following COVID-19 infection is well-described syndrome in children, only recently has it come to light that it can occur in adults. The exact incidence is unknown, but it is thought to be rare. A recent systematic review found only 221 cases of MIS-A, which could be included for analysis. Symptoms vary, but the most frequent include fever, gastrointestinal, and mucocutaneous. Many patients progress to multi-organ failure and require vasopressor support. 7% succumb to the illness. The pathophysiology of MIS is only partly understood. It shares similarities with Kawasaki disease, macrophage activation syndrome, and cytokine release syndrome. Importantly, by definition, the patient must have an absence of severe respiratory symptoms. It is thought to be due to a dysregulated immune response to the virus. Potential mechanisms include reduced levels of neutralising antibodies and autoreactive antibodies that promote inflammation. Further research into MIS-A is needed. Although rare, this potentially fatal syndrome should be considered in the unwell surgical patient who has recently contracted COVID-19 and poses a diagnostic dilemma.

Keywords: acute-abdomen, MIS, COVID-19, ICU

Procedia PDF Downloads 100

Authors: Chung-Ming Lo, Chung-Chien Lee

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In many countries, the lifetime prevalence of shoulder pain is up to 70%. In America, the health care system spends 7 billion per year about the healthy issues of shoulder pain. With respect to the origin, up to 70% of shoulder pain is attributed to rotator cuff lesions This study proposed a computer-aided diagnosis (CAD) system to assist radiologists classifying rotator cuff lesions with less operator dependence. Quantitative features were extracted from the shoulder ultrasound images acquired using an ALOKA alpha-6 US scanner (Hitachi-Aloka Medical, Tokyo, Japan) with linear array probe (scan width: 36mm) ranging from 5 to 13 MHz. During examination, the postures of the examined patients are standard sitting position and are followed by the regular routine. After acquisition, the shoulder US images were drawn out from the scanner and stored as 8-bit images with pixel value ranging from 0 to 255. Upon the sonographic appearance, the boundary of each lesion was delineated by a physician to indicate the specific pattern for analysis. The three lesion categories for classification were composed of 20 cases of tendon inflammation, 18 cases of calcific tendonitis, and 18 cases of supraspinatus tear. For each lesion, second-order statistics were quantified in the feature extraction. The second-order statistics were the texture features describing the correlations between adjacent pixels in a lesion. Because echogenicity patterns were expressed via grey-scale. The grey-scale co-occurrence matrixes with four angles of adjacent pixels were used. The texture metrics included the mean and standard deviation of energy, entropy, correlation, inverse different moment, inertia, cluster shade, cluster prominence, and Haralick correlation. Then, the quantitative features were combined in a multinomial logistic regression classifier to generate a prediction model of rotator cuff lesions. Multinomial logistic regression classifier is widely used in the classification of more than two categories such as the three lesion types used in this study. In the classifier, backward elimination was used to select a feature subset which is the most relevant. They were selected from the trained classifier with the lowest error rate. Leave-one-out cross-validation was used to evaluate the performance of the classifier. Each case was left out of the total cases and used to test the trained result by the remaining cases. According to the physician’s assessment, the performance of the proposed CAD system was shown by the accuracy. As a result, the proposed system achieved an accuracy of 86%. A CAD system based on the statistical texture features to interpret echogenicity values in shoulder musculoskeletal ultrasound was established to generate a prediction model for rotator cuff lesions. Clinically, it is difficult to distinguish some kinds of rotator cuff lesions, especially partial-thickness tear of rotator cuff. The shoulder orthopaedic surgeon and musculoskeletal radiologist reported greater diagnostic test accuracy than general radiologist or ultrasonographers based on the available literature. Consequently, the proposed CAD system which was developed according to the experiment of the shoulder orthopaedic surgeon can provide reliable suggestions to general radiologists or ultrasonographers. More quantitative features related to the specific patterns of different lesion types would be investigated in the further study to improve the prediction.

Keywords: shoulder ultrasound, rotator cuff lesions, texture, computer-aided diagnosis

Procedia PDF Downloads 257

Authors: Eun-Soo Lim, Young-Min Kang

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M-type Sr-hexaferrite (SrFe₁₂O₁₉) have been studied during the past decades because it is the most utilized materials in permanent magnets due to their low price, outstanding chemical stability, and appropriate hard magnetic properties. Many attempts have been made to improve the intrinsic magnetic properties of M-type Sr-hexaferrites (SrM), such as by improving the saturation magnetization (MS) and crystalline anisotropy by cation substitution. It is well proved that the Ca-La-Co substitutions are one of the most successful approaches, which lead to a significant enhancement in the crystalline anisotropy without reducing MS, and thus the Ca-La-Co-doped SrM have been commercialized in high-grade magnet products. In this research, the effect of respective doping of Ca and La into the SrM lattices were studied with assumptions that these elements could substitute both of Fe and Sr sites. The hexaferrite samples of stoichiometric SrFe₁₂O₁₉ (SrM) and the Ca substituted SrM with formulae of Sr₁₋ₓCaₓFe₁₂Oₐ (x = 0.1, 0.2, 0.3, 0.4) and SrFe₁₂₋ₓCaₓOₐ (x = 0.1, 0.2, 0.3, 0.4), and also La substituted SrM of Sr₁₋ₓLaₓFe₁₂Oₐ (x = 0.1, 0.2, 0.3, 0.4) and SrFe₁₂₋ₓLaₓOₐ (x = 0.1, 0.2, 0.3, 0.4) were prepared by conventional solid state reaction processes. X-ray diffraction (XRD) with a Cu Kα radiation source (λ=0.154056 nm) was used for phase analysis. Microstructural observation was conducted with a field emission scanning electron microscopy (FE-SEM). M-H measurements were performed using a vibrating sample magnetometer (VSM) at 300 K. Almost pure M-type phase could be obtained in the all series of hexaferrites calcined at > 1250 ºC. Small amount of Fe₂O₃ phases were detected in the XRD patterns of Sr₁₋ₓCaₓFe₁₂Oₐ (x = 0.2, 0.3, 0.4) and Sr₁₋ₓLaₓFe₁₂Oₐ (x = 0.1, 0.2, 0.3, 0.4) samples. Also, small amount of unidentified secondary phases without the Fe₂O₃ phase were found in the samples of SrFe₁₂₋ₓCaₓOₐ (x = 0.4) and SrFe₁₂₋ₓLaₓOₐ (x = 0.3, 0.4). Although the Ca substitution (x) into SrM structure did not exhibit a clear tendency in the cell parameter change in both series of samples, Sr₁₋ₓCaₓFe₁₂Oₐ and SrFe₁₂₋ₓCaₓOₐ , the cell volume slightly decreased with doping of Ca in the Sr₁₋ₓCaₓFe₁₂Oₐ samples and increased in the SrFe₁₂₋ₓCaₓOₐ samples. Considering relative ion sizes between Sr²⁺ (0.113 nm), Ca²⁺ (0.099 nm), Fe³⁺ (0.064 nm), these results imply that the Ca substitutes both of Sr and Fe in the SrM. A clear tendency of cell parameter change was observed in case of La substitution into Sr site of SrM ( Sr₁₋ₓLaₓFe₁₂Oₐ); the cell volume decreased with increase of x. It is owing to the similar but smaller ion size of La³⁺ (0.106 nm) than that of Sr²⁺. In case of SrFe₁₂₋ₓLaₓOₐ, the cell volume first decreased at x = 0.1 and then remained almost constant with increase of x from 0.2 to 0.4. These results mean that La only substitutes Sr site in the SrM structure. Besides, the microstructure and magnetic properties of these samples, and correlation between them will be revealed.

Keywords: M-type hexaferrite, substitution, cell parameter, magnetic properties

Procedia PDF Downloads 185

Authors: Rob Schindler

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Industry-standard methods of mitigating erosion of seabed sediments rely on ‘hard engineering’ approaches which have numerous environmental shortcomings: (1) direct loss of habitat by smothering of benthic species, (2) disruption of sediment transport processes, damaging geomorphic and ecosystem functionality (3) generation of secondary erosion problems, (4) introduction of material that may propagate non-local species, and (5) provision of pathways for the spread of invasive species. Recent studies have also revealed the importance of biological cohesion, the result of naturally occurring extra-cellular polymeric substances (EPS), in stabilizing natural sediments. Mimicking the strong bonding kinetics through the deliberate addition of EPS to sediments – henceforth termed ‘biostabilisation’ - offers a means in which to mitigate against erosion induced by structures or episodic increases in hydrodynamic forcing (e.g. storms and floods) whilst avoiding, or reducing, hard engineering. Here we present unique experiments that systematically examine how biostabilisation reduces scour around a monopile in a current, a first step to realizing the potential of this new method of scouring reduction for a wide range of engineering purposes in aquatic substrates. Experiments were performed in Plymouth University’s recirculating sediment flume which includes a recessed scour pit. The model monopile was 0.048 m in diameter, D. Assuming a prototype monopile diameter of 2.0 m yields a geometric ratio of 41.67. When applied to a 10 m prototype water depth this yields a model depth, d, of 0.24 m. The sediment pit containing the monopile was filled with different biostabilised substrata prepared using a mixture of fine sand (D50 = 230 μm) and EPS (Xanthan gum). Nine sand-EPS mixtures were examined spanning EPS contents of 0.0% < b0 < 0.50%. Scour development was measured using a laser point gauge along a 530 mm centreline at 10 mm increments at regular periods over 5 h. Maximum scour depth and excavated area were determined at different time steps and plotted against time to yield equilibrium values. After 5 hours the current was stopped and a detailed scan of the final scour morphology was taken. Results show that increasing EPS content causes a progressive reduction in the equilibrium depth and lateral extent of scour, and hence excavated material. Very small amounts equating to natural communities (< 0.1% by mass) reduce scour rate, depth and extent of scour around monopiles. Furthermore, the strong linear relationships between EPS content, equilibrium scour depth, excavation area and timescales of scouring offer a simple index on which to modify existing scour prediction methods. We conclude that the biostabilisation of sediments with EPS may offer a simple, cost-effective and ecologically sensitive means of reducing scour in a range of contexts including OWFs, bridge piers, pipeline installation, and void filling in rock armour. Biostabilisation may also reduce economic costs through (1) Use of existing site sediments, or waste dredged sediments (2) Reduced fabrication of materials, (3) Lower transport costs, (4) Less dependence on specialist vessels and precise sub-sea assembly. Further, its potential environmental credentials may allow sensitive use of the seabed in marine protection zones across the globe.

Keywords: biostabilisation, EPS, marine, scour

Procedia PDF Downloads 147

Authors: Parag Katira, Frederika Rentzeperis, Zuzanna Nowicka, Giada Fiandaca, Thomas Veith, Jack Farinhas, Noemi Andor

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Resource limitations shape the outcome of competitions between genetically heterogeneous pre-malignant cells. One example of such heterogeneity is in the ploidy (DNA content) of pre-malignant cells. A whole-genome duplication (WGD) transforms a diploid cell into a tetraploid one and has been detected in 28-56% of human cancers. If a tetraploid subclone expands, it consistently does so early in tumor evolution, when cell density is still low, and competition for nutrients is comparatively weak – an observation confirmed for several tumor types. WGD+ cells need more resources to synthesize increasing amounts of DNA, RNA, and proteins. To quantify resource limitations and how they relate to ploidy, we performed a PAN cancer analysis of WGD, PET/CT, and MRI scans. Segmentation of >20 different organs from >900 PET/CT scans were performed with MOOSE. We observed a strong correlation between organ-wide population-average estimates of Oxygen and the average ploidy of cancers growing in the respective organ (Pearson R = 0.66; P= 0.001). In-vitro experiments using near-diploid and near-tetraploid lineages derived from a breast cancer cell line supported the hypothesis that DNA content influences Glucose- and Oxygen-dependent proliferation-, death- and migration rates. To model how subpopulations with variable DNA content compete in the resource-limited environment of the human brain, we developed a stochastic state-space model of the brain (S3MB). The model discretizes the brain into voxels, whereby the state of each voxel is defined by 8+ variables that are updated over time: stiffness, Oxygen, phosphate, glucose, vasculature, dead cells, migrating cells and proliferating cells of various DNA content, and treat conditions such as radiotherapy and chemotherapy. Well-established Fokker-Planck partial differential equations govern the distribution of resources and cells across voxels. We applied S3MB on sequencing and imaging data obtained from a primary GBM patient. We performed whole genome sequencing (WGS) of four surgical specimens collected during the 1ˢᵗ and 2ⁿᵈ surgeries of the GBM and used HATCHET to quantify its clonal composition and how it changes between the two surgeries. HATCHET identified two aneuploid subpopulations of ploidy 1.98 and 2.29, respectively. The low-ploidy clone was dominant at the time of the first surgery and became even more dominant upon recurrence. MRI images were available before and after each surgery and registered to MNI space. The S3MB domain was initiated from 4mm³ voxels of the MNI space. T1 post and T2 flair scan acquired after the 1ˢᵗ surgery informed tumor cell densities per voxel. Magnetic Resonance Elastography scans and PET/CT scans informed stiffness and Glucose access per voxel. We performed a parameter search to recapitulate the GBM’s tumor cell density and ploidy composition before the 2ⁿᵈ surgery. Results suggest that the high-ploidy subpopulation had a higher Glucose-dependent proliferation rate (0.70 vs. 0.49), but a lower Glucose-dependent death rate (0.47 vs. 1.42). These differences resulted in spatial differences in the distribution of the two subpopulations. Our results contribute to a better understanding of how genomics and microenvironments interact to shape cell fate decisions and could help pave the way to therapeutic strategies that mimic prognostically favorable environments.

Keywords: tumor evolution, intra-tumor heterogeneity, whole-genome doubling, mathematical modeling

Procedia PDF Downloads 48

Authors: Amrit Vasdev, Edwin Rho, Gurinder Vasdev

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Robotic surgery has enabled a new spectrum of minimally invasive breast reconstruction by improving visualization, surgeon posturing, and improved patient outcomes.1 The DaVinci robot system can be utilized in nipple sparing mastectomies and reconstructions. The process involves the insufflation of the subglandular space and a dissection of the mammary gland with a combination of cautery and blunt dissection. This case outlines a 35-year-old woman who has a long-standing family history of breast cancer and a diagnosis of a deleterious BRCA2 genetic mutation. She has decided to proceed with bilateral nipple sparing mastectomies with implants. Her perioperative mammogram and MRI were negative for masses, however, her left internal mammary lymph node was enlarged. She has taken oral contraceptive pills for 3-5 years and denies DES exposure, radiation therapy, human replacement therapy, or prior breast surgery. She does not smoke and rarely consumes alcohol. During the procedure, the patient received a standardized anesthetic for out-patient surgery of propofol infusion, succinylcholine, sevoflurane, and fentanyl. Aprepitant was given as an antiemetic and preoperative Tylenol and gabapentin for pain management. Concerns for the patient during the procedure included CO2 insufflation into the subcutaneous space. With CO2 insufflation, there is a potential for rapid uptake leading to severe acidosis, embolism, and subcutaneous emphysema.2To mitigate this, it is important to hyperventilate the patient and reduce both the insufflation pressure and the CO2 flow rate to the minimal acceptable by the surgeon. For intraoperative monitoring during this 6-9 hour long procedure, it has been suggested to utilize an Arterial-Line for end-tidal CO2 monitoring. However, in this case, it was not necessary as the patient had excellent cardiovascular reserve, and end-tidal CO2 was within normal limits for the duration of the procedure. A BIS monitor was also utilized to reduce anesthesia burden and to facilitate a prompt discharge from the PACU. Minimal Invasive Robotic Surgery will continue to evolve, and anesthesiologists need to be prepared for the new challenges ahead. Based on our limit number of patients, robotic mastectomy appears to be a safe alternative to open surgery with the promise of clearer tissue demarcation and better cosmetic results.

Keywords: anesthesia, mastectomies, robotic, hypercarbia

Procedia PDF Downloads 74

Authors: Rajashree Bothale, Venkateswara Rao

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Indian Himalayas also known as third pole with 0.9 Million SQ km area, contain the largest reserve of ice and snow outside poles and affect global climate and water availability in the perennial rivers. The variations in the extent of snow are indicative of climate change. The snow melt is sensitive to climate change (warming) and also an influencing factor to the climate change. A study of the spatio-temporal dynamics of snow cover and melt/freeze conditions is carried out using space based observations in visible and microwave bands. An analysis period of 2003 to 2015 is selected to identify and map the changes and trend in snow cover using Indian Remote Sensing (IRS) Advanced Wide Field Sensor (AWiFS) and Moderate Resolution Imaging Spectroradiometer(MODIS) data. For mapping of wet snow, microwave data is used, which is sensitive to the presence of liquid water in the snow. The present study uses Ku-band scatterometer data from QuikSCAT and Oceansat satellites. The enhanced resolution images at 2.25 km from the 13.6GHz sensor are used to analyze the backscatter response to dry and wet snow for the period of 2000-2013 using threshold method. The study area is divided into three major river basins namely Brahmaputra, Ganges and Indus which also represent the diversification in Himalayas as the Eastern Himalayas, Central Himalayas and Western Himalayas. Topographic variations across different zones show that a majority of the study area lies in 4000–5500 m elevation range and the maximum percent of high elevated areas (>5500 m) lies in Western Himalayas. The effect of climate change could be seen in the extent of snow cover and also on the melt/freeze status in different parts of Himalayas. Melt onset day increases from east (March11+11) to west (May12+15) with large variation in number of melt days. Western Himalayas has shorter melt duration (120+15) in comparison to Eastern Himalayas (150+16) providing lesser time for melt. Eastern Himalaya glaciers are prone for enhanced melt due to large melt duration. The extent of snow cover coupled with the status of melt/freeze indicating solar radiation can be used as precursor for monsoon prediction.

Keywords: Indian Himalaya, Scatterometer, Snow Melt/Freeze, AWiFS, Cryosphere

Procedia PDF Downloads 232

Authors: Michel Soto Chalhoub

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Building designers in the Mediterranean region and other parts of the world utilize natural stone panels on the exterior façades as skin cover. This type of finishing is not only intended for aesthetic reasons but also environmental. The stone, since the earliest ages of civilization, has been used in construction and to-date some of the most appealing buildings owe their beauty to stone finishing. The stone also provides warmth in winter and freshness in summer as it moderates heat transfer and absorbs radiation. However, as structural codes became increasingly stringent about the dynamic performance of buildings, it became essential to study the performance of stone panels under cyclic loading – a condition that arises under the building is subjected to wind or earthquakes. The present paper studies the performance of stone panels using mechanical connectors when subjected to load reversal. In this paper, we present a theoretical model that addresses modes of failure in the steel connectors, by yield, and modes of failure in the stone, by fracture. Then we provide an experimental set-up and test results for rectangular stone panels of varying thickness. When the building is subjected to an earthquake, its rectangular panels within the structural system are subjected to shear deformations, which in turn impart stress into the stone cover. Rectangular stone panels, which typically range from 40cmx80cm to 60cmx120cm, need to be designed to withstand transverse loading from the direct application of lateral loads, and to withstand simultaneously in-plane loading (membrane stress) caused by inter-story drift and overall building lateral deflection. Results show correlation between the theoretical model which we derive from solid mechanics fundamentals and the experimental results, and lead to practical design recommendations. We find that for panel thickness below a certain threshold, it is more advantageous to utilize structural adhesive materials to connect stone panels to the main structural system of the building. For larger panel thicknesses, it is recommended to utilize mechanical connectors with special detailing to ensure a minimum level of ductility and energy dissipation.

Keywords: solid mechanics, cyclic loading, mechanical connectors, natural stone, seismic, wind, building skin

Procedia PDF Downloads 236

Authors: Geliashvili T. M., Tyulyandina A. S., Valiev A. K., Kononets P. V., Kharatishvili T. K., Salkov A. G., Pronin A. I., Gadzhieva E. H., Parnas A. V., Ilyakov V. S.

Abstract:

Aim/Introduction: Metastasis (Mts) to the sternum, while extremely rare in differentiated thyroid cancer (DTC) (1), requires a personalized, multidisciplinary treatment approach. In aggressively growing Mts to the sternum, which rapidly become unresectable, a comprehensive therapeutic and diagnostic approach is particularly important. Materials and methods: We present a clinical case of solitary Mts to the sternum as first manifestation of a papillary thyroid microcarcinoma in a 55-year-old man. Results: 18F-FDG PET/CT after thyroidectomy confirmed the solitary Mts to the sternum with extremely high FDG uptake (SUVmax=71,1), which predicted its radioiodine-refractory (RIR). Due to close attachment to the mediastinum and rapid growth, Mts was considered unresectable. During the next three months, the patient received targeted therapy with the tyrosine kinase inhibitor (TKI) Lenvatinib 24 mg per day. 1st course of radioiodine therapy (RIT) 6 GBq was also performed, the results of which confirmed the RIR of the tumor process. As a result of systemic therapy (targeted therapy combined with RIT and suppressive hormone therapy with L-thyroxine), there was a significant biochemical response (decrease of serum thyroglobulin level from 50,000 ng/ml to 550 ng/ml) and a partial response with decrease of tumor size (from 80x69x123 mm to 65x50x112 mm) and decrease of FDG accumulation (SUVmax from 71.1 to 63). All of this made possible to perform surgical treatment of Mts - sternal extirpation with its replacement by an individual titanium implant. At the control examination, the stimulated thyroglobulin level was only 134 ng/ml, and PET/CT revealed postoperative areas of 18F-FDG metabolism in the removed sternal Mts. Also, 18F-FDG PET/CT in the early (metabolic) stage revealed two new bone Mts (in the area of L3 SUVmax=17,32 and right iliac bone SUVmax=13,73), which, as well as the removed sternal Mts, appeared to be RIRs at the 2nd course of RIT 6 GBq. Subsequently, on 02.2022, external beam radiation therapy (EBRT) was performed on the newly identified oligometastatic bone foci. At present, the patient is under dynamic monitoring and in the process of suppressive hormone therapy with L-thyroxine. Conclusion: Thus, only due to the early prescription of targeted TKI therapy was it possible to perform surgical resection of Mts to the sternum, thereby improve the patient's quality of life and preserve the possibility of radical treatment in case of oligometastatic disease progression.

Keywords: differentiated thyroid cancer, metastasis to the sternum, radioiodine therapy, radioiodine-refractory cancer, targeted therapy, lenvatinib

Procedia PDF Downloads 85

Authors: Hernan Arturo Blas López, Gustavo Henndel Lopes, Antonio Carlos Silva Costa Teixeira, Carmen Elena Flores Barreda, Patricia Araujo Pantoja

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Phenols are toxic for life and the environment and may come from many sources. Uncured phenolic monomers present in phenolic resins used as binders in grinding wheels and emery paper can contaminate industrial wastewaters in abrasives manufacture plants. Furthermore, vestiges of resol and novolacs resins generated by wear and tear of abrasives are also possible sources of water contamination by phenolics in these facilities. Fortunately, advanced oxidation by dark Fenton and photo-Fenton techniques are capable of oxidizing phenols and their degradation products up to their mineralization into H₂O and CO₂. The maximal allowable concentrations for phenols in Peruvian waterbodies is very low, such that insufficiently treated effluents from the abrasives industry are a potential environmental noncompliance. The current case study highlights findings obtained during the lab-scale application of Fenton’s and photo-assisted Fenton’s chemistries to real industrial wastewater samples from an abrasives manufacture plant in Peru. The goal was to reduce the phenolic content and sample toxicity. For this purpose, two independent variables-reaction time and effect of ultraviolet radiation–were studied as for their impacts on the concentration of total phenols, total organic carbon (TOC), biological oxygen demand (BOD) and chemical oxygen demand (COD). In this study, diluted samples (1 L) of the industrial effluent were treated with Fenton’s reagent (H₂O₂ and Fe²⁺ from FeSO₄.H₂O) during 10 min in a photochemical batch reactor (Alphatec RFS-500, Brazil) at pH 2.92. In the case of photo-Fenton tests with ultraviolet lamps of 9 W, UV-A, UV-B and UV-C lamps were evaluated. All process conditions achieved 100% of phenols degraded within 5 minutes. TOC, BOD and COD decreased by 49%, 52% and 86% respectively (all processes together). However, Fenton treatment was not capable of reducing BOD, COD and TOC below a certain value even after 10 minutes, contrarily to photo-Fenton. It was also possible to conclude that the processes here studied degrade other compounds in addition to phenols, what is an advantage. In all cases, elevated effluent dilution factors and high amounts of oxidant agent impact negatively the overall economy of the processes here investigated.

Keywords: fenton oxidation, wastewater treatment, phenols, abrasives industry

Procedia PDF Downloads 288

Authors: Lubaina Soni, Claire Farrell, Christopher Szota, Tim D. Fletcher

Abstract:

Green roofs are a promising engineered ecosystem for reducing stormwater runoff and restoring vegetation cover in cities. Plants can contribute to rainfall retention by rapidly depleting water in the substrate; however, this increases the risk of plant drought stress. Green roof configurations, therefore, need to provide plants the opportunity to efficiently deplete the substrate but also avoid severe drought stress. This study used green roof modules placed in a rainout shelter during a six-month rainfall regime simulated in Melbourne, Australia. Rainfall was applied equally with an overhead irrigation system on each module. Aside from rainfall, modules were under natural climatic conditions, including temperature, wind, and radiation. A single species, Ficinia nodosa, was planted with five different treatments and three replicates of each treatment. In this experiment, we tested the impact of three plant cover treatments (0%, 50% and 100%) on rainfall retention and plant drought stress. We also installed two runoff zone treatments covering 50% of the substrate surface for additional modules with 0% and 50% plant cover to determine whether directing rainfall resources towards plant roots would reduce drought stress without impacting rainfall retention. The retention performance for the simulated rainfall events was measured, quantifying all components for hydrological performance and survival on green roofs. We found that evapotranspiration and rainfall retention were similar for modules with 50% and 100% plant cover. However, modules with 100% plant cover showed significantly higher plant drought stress. Therefore, planting at a lower cover/density reduced plant drought stress without jeopardizing rainfall retention performance. Installing runoff zones marginally reduced evapotranspiration and rainfall retention, but by approximately the same amount for modules with 0% and 50% plant cover. This indicates that reduced evaporation due to the installation of the runoff zones likely contributed to reduced evapotranspiration and rainfall retention. Further, runoff occurred from modules with runoff zones faster than those without, indicating that we created a faster pathway for water to enter and leave the substrate, which also likely contributed to lower overall evapotranspiration and retention. However, despite some loss in retention performance, modules with 50% plant cover installed with runoff zones showed significantly lower drought stress in plants compared to those without runoff zones. Overall, we suggest that reducing plant cover represents a simple means of optimizing green roof performance but creating runoff zones may reduce plant drought stress at the cost of reduced rainfall retention.

Keywords: green roof, plant cover, plant drought stress, rainfall retention

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Authors: Vladimir Hovhannisyan, Chen Yuan Dong

Abstract:

Recently nanoparticles (NPs) have been introduced in biomedicine as effective agents for cancer-targeted drug delivery and noninvasive tissue imaging. The most important requirements to these agents are their non-toxicity, biocompatibility and stability. In view of these criteria, the zeolite (ZL) nanoparticles (NPs) may be considered as perfect candidates for biomedical applications. ZLs are crystalline aluminosilicates consisting of oxygen-sharing SiO4 and AlO4 tetrahedral groups united by common vertices in three-dimensional framework and containing pores with diameters from 0.3 to 1.2 nm. Generally, the behavior and physical properties of ZLs are studied by SEM, X-ray spectroscopy, and AFM, whereas optical spectroscopic and microscopic approaches are not effective enough, because of strong scattering in common ZL bulk materials and powders. The light scattering can be reduced by using of ZL NPs. ZL NPs have large external surface area, high dispersibility in both aqueous and organic solutions, high photo- and thermal stability, and exceptional ability to adsorb various molecules and atoms in their nanopores. In this report, using multiphoton microscopy and nonlinear spectroscopy, we investigate nonlinear optical properties of clinoptilolite type of ZL micro- and nanoparticles with average diameters of 2200 nm and 240 nm, correspondingly. Multiphoton imaging is achieved using a laser scanning microscope system (LSM 510 META, Zeiss, Germany) coupled to a femtosecond titanium:sapphire laser (repetition rate- 80 MHz, pulse duration-120 fs, radiation wavelength- 720-820 nm) (Tsunami, Spectra-Physics, CA). Two Zeiss, Plan-Neofluar objectives (air immersion 20×∕NA 0.5 and water immersion 40×∕NA 1.2) are used for imaging. For the detection of the nonlinear response, we use two detection channels with 380-400 nm and 435-700 nm spectral bandwidths. We demonstrate that ZL micro- and nanoparticles can produce nonlinear optical response under the near-infrared femtosecond laser excitation. The interaction of hypericine, chlorin e6 and other dyes with ZL NPs and their photodynamic activity is investigated. Particularly, multiphoton imaging shows that individual ZL NPs particles adsorb Zn-tetraporphyrin molecules, but do not adsorb fluorescein molecules. In addition, nonlinear spectral properties of ZL NPs in native biotissues are studied. Nonlinear microscopy and spectroscopy may open new perspectives in the research and application of ZL NP in biomedicine, and the results may help to introduce novel approaches into the clinical environment.

Keywords: multiphoton microscopy, nanoparticles, nonlinear optics, zeolite

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Authors: Elena Parmentier, Henrik Endeman

Abstract:

Introduction: Large mediastinal masses often present with diagnostic and clinical challenges due to compression of the respiratory and hemodynamic system. We present a case of a mediastinal mass with symptomatic mechanical compression of the trachea, resulting in challenging airway management. Methods: We present a case of 66-year-old male, complaining of progressive dysphagia. Initial esophagogastroscopy revealed a stenosis secondary to external compression, biopsies were inconclusive. Additional CT scan showed a large mediastinal mass of unknown origin, situated between the vertebrae and esophagus. Symptoms progressed and patient developed dyspnea and stridor. A new CT showed quick growth of the mass with compression of the trachea, subglottic to just above the carina. A tracheal covered stent was successfully placed. Endobronchial ultrasound revealed a large irregular mass without tracheal invasion, biopsies were taken. 4 days after stent placement, the patients’ condition deteriorated with worsening of stridor, dyspnea and desaturation. Migration of the tracheal stent into the right main bronchus was seen on chest X ray, with obstruction of the left main bronchus and secondary atelectasis. Different methods have been described in the literature for tracheobronchial stent removal (surgical, endoscopic, fluoroscopyguided), our first choice in this case was flexible bronchoscopy. However, this revealed tracheal compression above the migrated stent and passage of the scope occurred impossible. Patient was admitted to the ICU, high-flow nasal oxygen therapy was started and the situation stabilized, giving time for extensive assessment and preparation of the airway management approach. Close cooperation between the intensivist, pulmonologist, anesthesiologist and otorhinolaryngologist was essential. Results: In case of sudden deterioration, a protocol for emergency situations was made. Given the increased risk of additional tracheal compression after administration of neuromuscular blocking agents, an approach with awake fiberoptic intubation maintaining spontaneous ventilation was proposed. However, intubation without retrieval of the tracheal stent was found undesirable due to expected massive shunting over the left atelectatic lung. As rescue option, assistance of extracorporeal circulation was considered and perfusionist was kept on standby. The patient stayed stable and was transferred to the operating theatre. High frequency jet ventilation under general anesthesia resulted in desaturations up to 50%, making rigid bronchoscopy impossible. Subsequently an endotracheal tube size 8 could be placed successfully and the stent could be retrieved via bronchoscopy over (and with) the tube, after which the patient was reintubated. Finally, a tracheostomy (Shiley™ Tracheostomy Tube With Cuff, size 8) was placed, fiberoptic control showed a patent airway. Patient was readmitted to the ICU and could be quickly weaned of the ventilator. Pathology was positive for rhabdomyosarcoma, without indication for systemic therapy. Extensive surgery (laryngectomy, esophagectomy) was suggested, but patient refused and palliative care was started. Conclusion: Due to meticulous planning in an interdisciplinary team, we showed a successful airway management approach in this complicated case of critical airway compression secondary to a rare rhabdomyosarcoma, complicated by tracheal stent migration. Besides presenting our thoughts and considerations, we support exploring other possible approaches of this specific clinical problem.

Keywords: airway management, rhabdomyosarcoma, stent displacement, tracheal stenosis

Procedia PDF Downloads 67

Authors: Aba-Carina Pârlog

Abstract:

On translating, reading against the grain results in a wrong effect in the TL. Quine’s ocular irradiation plays an important part in the process of understanding and translating a text. The various types of textual radiation must be rendered by the translator by paying close attention to the types of field that produce it. The literary work must be seen as an indirect cause of an expressive effect in the TL that is supposed to be similar to the effect it has in the SL. If the adaptive transformative codes are so flexible that they encourage the translator to repeatedly leave out parts of the original work, then a subversive pattern emerges which changes the entire book. In this case, the translator is a writer per se who decides what goes in and out of the book, how the style is to be ciphered and what elements of ideology are to be highlighted. Figurative language must not be flattened for the sake of clarity or naturalness. The missing figurative elements make the translated text less interesting, less challenging and less vivid which reflects poorly on the writer. There is a close connection between style and the writer’s person. If the writer’s style is very much changed in a translation, the translation is useless as the original writer and his / her imaginative world can no longer be discovered. Then, a different writer appears and his / her creation surfaces. Changing meaning considered as a “negative shift” in translation defines one of the faulty transformative codes used by some translators. It is a dangerous tool which leads to adaptations that sometimes reflect the original less than the reader would wish to. It contradicts the very essence of the process of translation which is that of making a work available in a foreign language. Employing speculative aesthetics at the level of a text indicates the wish to create manipulative or subversive effects in the translated work. This is generally achieved by adding new words or connotations, creating new figures of speech or using explicitations. The irradiation patterns of the original work are neglected and the translator creates new meanings, implications, emphases and contexts. Again s/he turns into a new author who enjoys the freedom of expressing his / her ideas without the constraints of the original text. The stimulus meaning of a text is very important for a translator which is why reading against the grain is unadvisable during the process of translation. By paying attention to the waves of the SL input, a faithful literary work is produced which does not contradict general knowledge about foreign cultures and civilizations. Following personal common sense is essential in the field of translation as well as everywhere else.

Keywords: stimulus meaning, substance of expression, transformative code, translation

Procedia PDF Downloads 427