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It is hypothesized that gliding bacteria move by producing waves on their own surface and leave an adhesive slime trail. Slime is basically a viscoelastic slippery material. Based on these observations, we use a mathematical model (of undulating sheet) to examine the locomotion of gliding bacteria over a layer of non-Newtonian slime. The constitutive equations of FENE-P model are employed to characterize the rheological behavior of the non-Newtonian slime. Moreover, substratum beneath the slime is approximated by a multi-sinusoidal sheet. A hybrid computational technique to solve the second order DE with a system of algebraic equations is presented. The speed of organism, flow rate and energy loss at larger values of the involved parameters are simulated using bvp5c in conjunction with a modified Newton-Raphson technique (MNRT). The comparison of soft and rigid substrate, slip and no-slip boundary conditions, Newtonian and non-Newtonian slime is displayed in several figures. Streamlines pattern and velocity of the slime are also drawn for the realistic pairs of speed and flow rate and are thoroughly explained.
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Bactérias , Locomoção , Modelos TeóricosRESUMO
Herein we report the fabrication of cationic functionalized cellulose nanofibers (c-CNF) having 0.13 mmol.g-1 ammonium content and its ionic crosslinking via the pad-batch process. The overall chemical modifications were justified through infrared spectroscopy. It is revealed that the tensile strength of ionic crosslinked c-CNF (zc-CNF) improved from 3.8 MPa to 5.4 MPa over c-CNF. The adsorption capacity of zc--CNF was found to be 158 mg.g-1 followed by the Thomas model. Further, the experimental data were used to train and test a series of machine learning (ML) models. A total of 23 various classical ML models (as a benchmark) were compared simultaneously using Pycaret which helped reduce the programming complexity. However, shallow, and deep neural networks are used that outperformed the classic machine learning models. The best classical-tuned ML model using Random Forests regression had an accuracy of 92.6 %. The deep neural network made effective by early stopping and dropout regularization techniques, with 20 × 6 (Neurons x Layers) configuration, showed an appreciable prediction accuracy of 96 %.
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Celulose , Nanofibras , Celulose/química , Nanofibras/química , Adsorção , Resistência à Tração , Espectrofotometria Infravermelho , ÍonsRESUMO
Bacteria are microscopic single-celled microbes that can only be spotted via a microscope. They occur in a variety of shapes and sizes, and their dimensions are measured in micrometers (one-millionth of a meter). Bacterial categorization is based on a variety of features such as morphology, DNA sequencing, presence of flagella, cell structure, staining techniques, oxygen, and carbon-dioxide requirements. Due to these classifications, gliding bacteria are a miscellaneous class of rodlike microorganisms that cling and propel over ooze slime connected with a substrate. Without the assistance of flagella, which are essential parts of bacterial motility, the organism movement is adopted by waves streaming down the outer layer of this microorganism. To simulate the locomotion of such gliding microorganisms, a wavy sheet over Oldroyd-4 constant fluid is utilized. Under the long wavelength assumption, the equations regulating the flow of slime (modeled as Oldroyd-4 constant slime) beneath the cell/organism are developed. The quantities such as slime flow rate, cell speed, and propulsion power are computed by using bvp4c (MATLAB routine) integrated with the modified Newton-Rasphson technique. Furthermore, the flow patterns and velocity of the slime are graphically shown and thoroughly described using precise (calculated) values of the cell speed and velocity of the slime.
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Bactérias , Locomoção , Movimento (Física) , Locomoção/fisiologiaRESUMO
Motility is defined as the movement of cells by some form of self-propulsion. Some organisms motile by using long flagella that quickly rotate to propel them over various surfaces (in swarming and swimming mechanism), while few motile without the aid of flagella (in twitching, sliding and gliding mechanism). Among these modes, gliding motility is adopted by a rod-shaped organism famously known as gliding bacteria. It is hypothesized that in such type of motility, organism motile under their own power by secreting a layer of slime on the substrate. In this study, an active wall is considered as a substrate and a two-dimensional wavy sheet as an organism. Slip effects are also employed in the current work. The physical properties of the slime are governed by a suitable constitutive equation of couple stress model. A sixth order BVP is obtained by utilizing lubrication assumption. For an appropriate fixed pair of flow rate and organism speed the BVP is solved by MATLAB built-in function bvp-5c. This solution is utilized in the mechanical equilibrium conditions which are obviously not satisfied yet. To satisfy these conditions, the pair of flow rate and gliding speed is refined by a root finding algorithm (modified Newton-Raphson method). By employing this numerical scheme, various figures are shown to demonstrate the effect of several associated parameters on organism speed, flow rate, energy expended by the glider, streamlines and longitudinal velocity. It is observed from the graphical results that organism speed and energy consumption is directly proportional to the couple stress parameter and slip effects.
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Algoritmos , Movimento , CinéticaRESUMO
BACKGROUND AND OBJECTIVE: Flow generated via peristaltic waves in naturally occurring physical phenomenon inside human body. Its combination with electric and magnetic forces makes it even more versatile in biomedical engineering applications. The results presented in this article are useful in designing artificial tubes, lab-on-a-chip devices for cell manipulation, drug design, flow amalgamation, micro-scale pumps and micro-bots which can be externally controlled by electric and magnetic sensors. Motivated by the aforesaid facts the current investigation is based on the transportation of a couple stress bio-fluid by peristalsis through a convergent channel under the postulates of creeping phenomena and long wavelength, respectively METHODS: A closed form solution is acquired for the axial velocity profile, volumetric flow rate and streamlines, respectively. The physical influence of involved parameters on the rheological characteristics are argued analytically with the help of Mathematica software 12.0.1 in detail. Additionally, the flow system is considered to take place under the both porosity and electro-magneto-hydrodynamics effects, respectively. The amplitude of axial velocity across one wavelength is strongly affected at the larger values of numerous embedded parameters: Darcy number, Hartmann number, Electro-osmotic velocity parameter and non-Newtonian (couple stress) parameter. RESULTS: We have observed remarkable effects of embedded parameters on velocity distribution, flow rate and trapping phenomena under porous and electro-osmotic (combination of both magnetic and electric) effects. The circulation of boluses and number of streamlines are reduced/enhanced for larger Hartmann number/Darcy number due strong magnetic/porosity effects. This research study additionally tells us how to control the transportation phenomena of biological fluids by appropriate adjusting the porosity effects (the effects of porous media) and electro-osmotic influences. Moreover, in order to enhance the performance of a peristaltic pump at the micro-scale level, we have used complex peristaltic wave scenario in the boundary walls of the convergent micro-channel.
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Fenômenos Eletromagnéticos , Hidrodinâmica , Porosidade , Reologia , Algoritmos , Bioengenharia , Humanos , Modelos BiológicosRESUMO
BACKGROUND: A shortage of organ donors exists in the UK and targeting family consent is key for increasing donation consent rates. Registration on the NHS Organ Donor Register (NHS ODR) facilitates this, as it guides families on their loved ones donation preference. In general practice, an opportunity to register is provided, however only to new patients. To improve access to registration opportunities, an intervention was designed where general practice staff asked their patients if they wished to register as an organ donor. AIM: To assess an organ donation registration intervention for feasibility and acceptability in a UK general practice setting. METHOD: One general practice, in Luton, UK, conducted the intervention for 3 months (April to July 2018). Training was held in March 2018, and leaflets and posters were displayed for the 3-month period. An embedded experimental mixed-methods design was used, with data collected via SystmONE questionnaires, surveys and focus groups. RESULTS: The intervention was found to be feasible and acceptable to conduct with some patients by some staff members. During the 3 months, patients were asked in 12.4% of face-to-face consultations (n=812). Nurses and healthcare assistants were more able to conduct the intervention than doctors. Lack of time, telephone consultations, and it not being appropriate were the most common reasons for not asking. Finally, 244 patients joined the NHS ODR; 30.4% of those asked. CONCLUSION: This study demonstrates that general practice could be a feasible location in which an intervention designed to increase NHS ODR registration could be conducted.
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BACKGROUND: Organ donor registration helps guide decision making for families. UK general practice provides the facility to register on the NHS Organ Donor Register, but only to new patients. An intervention was developed to present a registration opportunity to existing patients in this setting. AIM: To assess the feasibility and acceptability of an organ donation intervention implemented in UK general practice. DESIGN AND SETTING: The intervention ran in a large practice in Luton in the UK, for 3 months in 2018. A single practice feasibility study was conducted using an embedded experimental mixed methods design. METHOD: Staff were trained to ask patients in consultations if they wished to join the register, and leaflets and posters were displayed in the waiting room. Data on feasibility and acceptability were captured using SystmONE questionnaires, surveys, and focus groups. RESULTS: Over 3 months, in 12.4% of face-to-face consultations, patients were asked if they would like to join the register (812 of 6569), and 244 (30.0%) of these patients joined the register. Common reasons staff did not ask patients were due to telephone consultations, lack of time, and it not being appropriate. Nurses and healthcare assistants performed prompted choice more than doctors (23.4%, 17.1%, and 1.6% respectively). Certain clinic types, such as phlebotomy or routine clinics, facilitated asking compared to those where patients presented with unknown or more serious issues. CONCLUSION: The intervention was found to be feasible and acceptable by some staff and patients. Feasibility criteria were met; therefore, the intervention can progress to further testing.
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Medicina Geral , Obtenção de Tecidos e Órgãos , Estudos de Viabilidade , Humanos , Inquéritos e Questionários , Doadores de TecidosRESUMO
BACKGROUND AND OBJECTIVE: The swimming mechanism of self-propelling organisms has been imitated by biomedical engineers to design the mechanical micro bots. The interaction of these swimmers with surrounding environment is another important aspect. The present swimming problem integrates Taylor sheet model with couple stress fluid model. The thin passage containing micro-swimmers and mucus is approximated as a rigid (passive) two-dimensional channel. The spermatozoa forms a pack quite similar as a complex wavy sheet. METHODS: Swimming problem with couple stress cervical liquid (at low Reynolds number) leads to a linear sixth order differential equation. The boundary value problem (BVP) is solved analytically with two unknowns i.e. speed of complex wavy sheet and flow rate of couple stress mucus. After utilizing this solution into equilibrium conditions these unknowns can be computed via Newton-Raphson algorithm. Furthermore, the pairs of numerically calculated organism speed and flow rate are utilized in the expression of power dissipation. RESULTS: This work describes that the speed of micro-swimmers can be enhanced by suitable rheology of the surrounding liquid. The usage of couple stress fluid as compared to Newtonian fluid enhances the energy dissipation and reduces the flow rate. On the other hand complex wavy surface also aids the organisms to swim faster.
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Colo do Útero/fisiologia , Muco/fisiologia , Algoritmos , Feminino , Humanos , Masculino , Modelos Biológicos , Reologia , Espermatozoides , Estresse Psicológico/metabolismoRESUMO
Every group of microorganism utilizes a diverse mechanical strategy to propel through complex environments. These swimming problems deal with the fluid-organism interaction at micro-scales in which Reynolds number is of the order of 10-3. By adopting the same propulsion mechanism of so-called Taylor's sheet, here we address the biomechanical principle of swimming via different wavy surfaces. The passage (containing micro-swimmers) is considered to be passive two-dimensional channel filled with viscoelastic liquid, i.e., Oldroyd-4 constant fluid. For some initial value of unknowns, i.e., cell speed and flow rate of surrounding liquid, the resulting boundary value problem is solved by robust finite difference scheme. This convergent solution is further employed in the equilibrium conditions which will obviously not be satisfied for such crude values of unknowns. These unknowns are further refined (to satisfy the equilibrium conditions) by modified Newton-Raphson algorithm. These computed pairs are also utilized to compute the energy losses. The speed of swimming sheet its power delivered and flow rate of Oldroyd-4 constant fluid are compared for different kinds of wavy sheets. These results are also useful in the manufacturing of artificial (soft) microbots and the optimization of locomotion strategies.
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Simulação por Computador , Campos Magnéticos , Magnetismo , Movimento , Reologia , Espermatozoides/fisiologia , Algoritmos , Animais , Fenômenos Biomecânicos , Elasticidade , Análise de Fourier , Humanos , Locomoção , Masculino , Modelos Teóricos , ViscosidadeRESUMO
BACKGROUND AND OBJECTIVE: Peristaltic is one of the most frequently occurring phenomenon in biological systems. These systems of the human body (especially digestive, reproductive, respiratory, renal system) generally involve effects of curvature, porosity, rheology and heat transfer. Thus, in the present investigation we integrate heat transfer phenomenon with Sisko fluid flowing through porous medium bounded within curved wavy walls. The theoretical analysis presented under long wavelength approximation serves as a model for the creeping non-isothermal flow of blood through a diseased segment of the artery due to vasomotion (peristaltic motion) in the artery. METHODS: The highly nonlinear ordinary differential equation with appropriate boundary conditions is solved using a well-tested implicit finite difference scheme. A comparison of velocity profile for Newtonian, power-law and Sisko fluids is also presented. RESULTS: The Sisko model predict higher values of velocity in the central core region than power-law and Newtonian model. The size of circulating bolus of fluid reduces with increasing permeability parameter. The symmetry in velocity and streamlines pattern is observed when dimensionless radius of curvature becomes very large.
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Hidrodinâmica , Modelos Teóricos , Temperatura Alta , PorosidadeRESUMO
BACKGROUND: New interventions are required to increase the number of people donating their organs after death. In the United States of America (USA), general practice has proved to be a successful location to increase organ donor registration. However, a dearth of research exists examining this in the United Kingdom (UK). due to the unique challenges presented by the National Health Service (NHS). This protocol outlines a feasibility study to assess whether UK general practice is a feasible and acceptable location for organ donation intervention targeting NHS Organ Donor Register (NHS ODR) membership. METHODS: The primary intervention element, prompted choice, requires general practice to ask patients in consultations if they wish to join the NHS ODR. Two additional intervention techniques will be used to support prompted choice: staff training and leaflets and posters. The intervention will run for 3 months (April-July 2018) followed by a period of data collection. The following methods will be used to assess feasibility, acceptability and fidelity: registration data, a training evaluation survey, focus groups with staff and online surveys for staff and patients. DISCUSSION: By examining the feasibility, acceptability and fidelity of a prompted choice intervention in UK general practice, important knowledge can be gathered on whether it is a suitable location to conduct this. Additional learning can also be gained generally for implementing interventions in general practice. This could contribute to the knowledge base concerning the feasibility of NHS general practice to host interventions. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number ISRTN44530504 (Jones et al, General practice organ donation intervention: a feasibility study ISRCTN44530504, 2017) Registration on 26 September 2017.
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This paper proposes a work step indication method for supporting daily work with a grid-pattern projection. To support an independent life of demented senior people, it is desirable that an instruction is easy to understand visually and not complicated. The proposed method in this paper uses a range image sensor and a camera in addition to a projector. A 3D geometry of a target scene is measured by the range image sensor, and the grid-pattern is projected onto the scene directly. Direct projection of the work step is easier to be associated with the target objects around the assisted person, and the grid-pattern is a solution to indicate the spatial instruction. A prototype has been implemented and has demonstrated that the proposed grid-pattern projection is easy to show the work step.