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Papers by umair khan

International Journal of Modern Physics B

This research aims to study the 3D magnetohydrodynamics stagnation-point flow (SPF) over a horizo... more This research aims to study the 3D magnetohydrodynamics stagnation-point flow (SPF) over a horizontal plane surface (HPS) carrying water-based graphene oxide (GO) nanoparticles caused by an irregular heat source/sink used in heat transfer procedures. In addition, a Tiwari–Das model is used to inspect the dynamics of fluid flow behavior and heat transmission features of the nanoparticles with experiencing the impacts of thermal radiation. The acquired nonlinear set of partial differential equations (PDEs) is transfigured to a system of ordinary differential equations (ODEs) using similarity transformations. The accumulative dimensionless ODEs are then further tackled in MATLAB using the bvp4c solver. Tables and figures are prepared for the execution of several relevant constraints along with nodal/saddle indicative parameter, internal heat source/sink parameter, radiation parameter and nanoparticles volume fraction which divulges and clarify more accurately the posited quantitative d...

International Journal of Modern Physics B

Among several aspects, the one contributing towards the difficulty of groundwater quality evaluat... more Among several aspects, the one contributing towards the difficulty of groundwater quality evaluation is the large diversity of contamination sources. As contaminants comprising various compounds move from the soil to the water table, they will travel through several hydrologic zones. In constant unidirectional flow fields, a mathematical study of simultaneous adsorption and dispersion of a solute inside homogeneous and isotropic permeable media is described. The solute is adsorbed at a rate proportionate to its concentration in the dispersion systems, which are susceptible to input concentrations that fluctuate exponentially with time. The advection–dispersion equation (ADE) was solved numerically in this work to analyze the pollutants transport bearing in mind the coefficient of distribution and permeability by considering pollutant input concentrations. The solution is derived using the Laplace transform and Duhamel’s theorem with moving coordinates. For specified medium and fluid...

Frontiers of Earth Science, 2021

Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir c... more Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir characteristics play important roles in assessment of hydrocarbon potential. Here, an approach that integrates digital elevation modelling, seismic interpretation, seismic attributes, three-dimensional (3D) geological structural modeling predicated on seismic data interpretation, and petrophysical analysis is presented to visualize and analyze reservoir structural trends and determine residual hydrocarbon potential. The digital elevation model is utilized to provide verifiable predictions of the Dhulian surface structure. Seismic interpretation of synthetic seismograms use twoway time and depth contour models to perform a representative 3D reservoir geological structure evaluation. Based on Petrel structural modeling efficiency, reservoir development indexes, such as the true 3D structural trends, slope, geometry type, depth, and possibility of hydrocarbon prospects, were calculated for the Eocene limestone Chorgali, upper Paleocene limestone Lockhart, early Permian arkosic sandstone Warcha, and Precambrian Salt Range formations. Trace envelope, instantaneous frequency, and average energy attribute analyses were utilized to resolve the spatial predictions of the subsurface structure, formation extrusion, and reflector continuity. We evaluated the average porosity, permeability, net to gross ratio, water saturation, and hydrocarbon saturation of early Eocene limestone and upper Paleocene limestone based on the qualitative interpretation of well log data. In summary, this integrated study validates 3D stratigraphic structural trends and fault networks, facilitates the residual hydrocarbon potential estimates, and reveals that the Dhulian area has a NE to SW (fold axis) thrust-bounded salt cored anticline structure, which substantiates the presence of tectonic compression. The thrust faults have fold axes trending from ENE to WSW, and the petrophysical analysis shows that the mapped reservoir is of good quality and has essential hydrocarbon potential, which can be exploited economically.

Lichen Planus first described by Erasmus Wilson in 1869 has moved from being regarded as an innoc... more Lichen Planus first described by Erasmus Wilson in 1869 has moved from being regarded as an innocuous benign condition to being considered as a potentially malignant disorder by the World Health Organization and is now defined as an idiopathic immune mediated mucocutaneous chronic inflammatory disease that affects the stratified squamous epithelia and the appendices. Oral lichen planus carries a very small probability of becoming malignant. The objective of the present study was to assess the long term prognostic aspects of oral squamous cell carcinoma/dysplasia and field cancerization occurring on the background of oral lichen planus in a retrospective analysis of 51 OLP patients (mean age=54 years; female, n=35; male, n=16) who between 2001 to middle of 2010 were diagnosed with OLP-related OSCC at the Department of Oral Medicine, Eastman Dental Institute and one major Head and Neck Cancer unit, University College London Hospital, United Kingdom. 1500 OLP patients were analyzed by ...

Biophysical Journal, 2021

Connexin-50 (Cx50) is among the most frequently mutated genes associated with congenital cataract... more Connexin-50 (Cx50) is among the most frequently mutated genes associated with congenital cataracts. While most of these disease-linked variants cause loss-of-function due to misfolding or aberrant trafficking, others directly alter channel properties. The mechanistic bases for such functional defects are mostly unknown. We investigated the functional and structural properties of a cataract-linked mutant, Cx50T39R (T39R), in the Xenopus oocyte system. T39R exhibited greatly enhanced hemichannel currents with altered voltage-gating properties compared to Cx50 and induced cell death. Coexpression of mutant T39R with wild-type Cx50 (to mimic the heterozygous state) resulted in hemichannel currents whose properties were indistinguishable from those induced by T39R alone, suggesting that the mutant had a dominant effect. Co-expression with Cx46 also produced channels with altered voltage-gating properties, particularly at negative potentials. All-atom molecular dynamics simulations indicate that the R39 substitution can form multiple electrostatic salt-bridge interactions between neighboring subunits that could stabilize the open-state conformation of the N-terminal domain, while also neutralizing the voltage-sensing residue D3 as well as residue E42 which participates in loop-gating. Together, these results suggest T39R acts as a dominant gain-of-function mutation that produces leaky hemichannels that may cause cytotoxicity in the lens and lead to development of cataracts. Statement of significance We investigated the functional and structural properties of a cataract-linked mutant, Cx50T39R (T39R), in the Xenopus oocyte system and showed that T39R exhibited greatly enhanced hemichannel currents with altered voltage-gating properties 3 compared to Cx50 and induced cell death. Consistent with our experimental findings, allatom equilibrium state molecular dynamics (MD) simulations of T39R show that R39 stabilized the open-state configuration of the N-terminal (NT) domain from an adjacent subunit. These results suggest that T39R causes disease by preventing the hemichannels from closing when present in the plasma membrane in the undocked state and provide an atomistic rationalization for the Cx50 disease-linked phenotype. They also expand our understanding of how connexin hemichannel channel gating is controlled.

Chinese Journal of Physics, 2021

International Journal of Numerical Methods for Heat & Fluid Flow, 2021

Purpose The boundary-layer analysis is required to reveal the fluid flow behavior in several indu... more Purpose The boundary-layer analysis is required to reveal the fluid flow behavior in several industrial processes and enhance the products’ effectiveness. Therefore, this research aims to investigate the buoyancy or mixed convective stagnation-point flow (SPF) and heat transfer of a micropolar fluid filled with hybrid nanoparticles over a vertical plate. The nanoparticles silver (Ag) and titanium dioxide (TiO2) are scattered into various base fluids to form a new-fangled class of (Ag-TiO2/various base fluid) hybrid nanofluid along with different shape factors. Design/methodology/approach The self-similarity transformations are used to reformulate the leading requisite partial differential equations into renovated non-linear dimensionless ordinary differential equations. The numerical dual solutions are gained for the transmuted requisite equations with the help of the bvp4c built-in package in MATLAB software. The results are validated by comparing them with previously available pub...

The European Physical Journal Applied Physics, 2020

The current study investigates MHD natural convection heat transfer of a hybrid nanofluid in a tr... more The current study investigates MHD natural convection heat transfer of a hybrid nanofluid in a truncated cone along with transparent domains having the stimulus of an inherent constant magnetic field. The governing equations subject to the physical boundary conditions are solved numerically by using the Galerkin finite element method. The effects of the various parameters involved in the problem such as the Rayleigh number Ra (ranging between 103 and 106), the Hartmann number Ha (ranging between 0 and 60), and the porosity ratio ε (0.1–0.9) are examined. Moreover, the effects of Da which represents the Darcy number (between 10‑3 and 10‑1) and the volume fraction of nanoparticles ϕ for the dissipated nanoparticles of Al2O3-Cu are reported in terms of the streamlines and isotherms distributions as well as the Nusselt number. Such parameters are critical control parameters for both the fluid flow and the rate of heat transfer of the natural convection in the annular space. The solution...

Case Studies in Thermal Engineering, 2021

Nanoliquid is a modern invention that is very promising in improving the heat transfer capabiliti... more Nanoliquid is a modern invention that is very promising in improving the heat transfer capabilities. The most critical disadvantage of classical nanoliquid models is that they cannot express categories of liquids that have definite microscopic characteristics that occur from the local structure and micro-rotation of the fluid elements. In this article, the features of the microrotation and heat transfer characteristics of a micropolar hybrid nanofluid flow towards a stagnation point on a stretching/shrinking sheet are analyzed numerically. The similarity transformation is utilized to transform the governing equations to a set of nonlinear ordinary differential equations before they are solved numerically using the function bvp4c in MATLAB software. The dual nature of solutions of shear stress, heat transfer, and micro-rotation gradient are illustrated for a broad range of pertaining parameters. The separation of boundary-layer takes place when multiple results fail to happen beyond a critical value of the shrinking parameter. The outcomes show that the separation of boundary layer is delayed due to mass suction parameter while the contrary behavior is observed for the effects of the volume fraction of nanoparticles. In addition, the friction factor initially uplifts and then declines due to suction for the first solution, while decelerates for the second solution but the heat transport and micro-rotation gradient enhance due to suction for both solutions. The temperature augments for both solution branches due to nanoparticles volume fraction while the micro-rotation and the velocity shrink for the first solution branch while uplift for the lower solution branch.

Journal of Molecular Liquids, 2021

Abstract The time-dependent stagnation point flow (SPF) and heat transfer of a water-based hybrid... more Abstract The time-dependent stagnation point flow (SPF) and heat transfer of a water-based hybrid nanofluid (Cu − Al2O3/Water) from a radially permeable shrinking or stretching surface is examined. The similarity technique is employed to transform the governing equations of hybrid nanofluid (Cu − Al2O3/Water) into similarity equations. These similarity equations are solved numerically using bvp4c function in MATLAB software. The numerical outcomes are acquired for particular values of the selected parameters. The results notice that dual solutions exist, up to a definite amount of the suction, unsteady strengths, and nanoparticle volume fraction. The critical amount declines due to nanoparticle volume fraction and augments due to suction and unsteady parameters. Also, it is seen that hybrid nanofluid (Cu − Al2O3/Water) augments the rate of heat transfer relative to the regular fluid. The temporal stability analysis is implemented to determine the stability of the dual solutions, and it is found that only one of them is stable and thus physically reliable as time passes.

Crystals, 2020

The current framework tackles the buoyancy flow via a slender revolution bodies comprising Molybd... more The current framework tackles the buoyancy flow via a slender revolution bodies comprising Molybdenum-Disulfide Graphene Oxide generalized hybrid nanofluid embedded in a porous medium. The impact of radiation is also provoked. The outcomes are presented in this analysis to examine the behavior of hybrid nanofluid flow (HNANF) through the cone, the paraboloid, and the cylinder-shaped bodies. The opposing flow (OPPF) as well as the assisting flow (ASSF) is discussed. The leading flow equations of generalized hybrid nanoliquid are worked out numerically by utilizing bvp4c solver. This sort of the problem may meet in the automatic industries connected to geothermal and geophysical applications where the sheet heat transport occurs. The impacts of engaging controlled parameters of the transmuted system on the drag force and the velocity profile are presented through the graphs and tables. The achieved outcomes suggest that the velocity upsurges due to the dimensionless radius of the slen...

Frontiers in Chemistry, 2020

Nisar et al. Mixed Squeezing Flow of Hybrid Ferroparticles augments due to the volume fraction of... more Nisar et al. Mixed Squeezing Flow of Hybrid Ferroparticles augments due to the volume fraction of nanoparticles in the assisting flow and declines in the opposing flow, while the opposite direction is noticed in the temperature field.

Processes, 2019

Entropy generation and dual solutions are rarely studied in the literature. An analysis is attemp... more Entropy generation and dual solutions are rarely studied in the literature. An analysis is attempted here. More exactly, the present paper looks at the impact of radiation of a micropolar fluid on mixed convective flow containing the titanium alloy Ti6Al4V nanoparticle along with a Riga plate. The study of dual-nature solution for the entropy generation along a Riga surface was not being explored in the literature; therefore, the current model focuses on the dual solutions of this complex nature model. Riga surface is identified as an actuator of electromagnetic in which electrodes are accumulated alternatively. This array produces the behavior of electromagnetic hydrodynamic in the flow field. The transmuted leading equations were worked out through the formula of 3-stage Lobatto IIIA. Influences of exercising enormous parameters on temperature distribution, velocity, and micro rotation fields are portrayed and argued. More than one solution is achieved in opposing flow, while in t...

Processes, 2019

A mathematical model comprising Darcy Forchheimer effects on the 3D nanofluid flow with engine oi... more A mathematical model comprising Darcy Forchheimer effects on the 3D nanofluid flow with engine oil as a base fluid containing suspended carbon nanotubes (CNTs) is envisioned. The CNTs are of both types i.e., multi-wall carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). The flow is initiated by an exponentially stretched surface. The impacts of Cattaneo–Christov heat flux along with velocity and thermal slip conditions are key factors in the novelty of the defined model. The boundary layer notion is designed to convert the compact form of equations into the component shape. Appropriate transformations lead to differential equations with high nonlinearity. The final non-dimensional system is solved numerically by a “MATLAB” function known as bvp4c. For both CNTs, different graphical sketches are drawn to present the influence of arising parameters versus related profiles. The outcomes show that higher slip parameter boosts the axial velocity, whereas fluid temperat...

Journal of Molecular Liquids, 2018

Nanofluid is the most promising gift of modern science to improve the heat transfer capabilities ... more Nanofluid is the most promising gift of modern science to improve the heat transfer capabilities of conventional heat transfer fluids. However, one of the most crucial drawbacks for classical nanofluid models is that they cannot describe a class of fluids that have certain microscopic characters arising from the micro-rotation and local structure of the fluid elements. In this work, the innovative micropolar nanofluid model is introduced to study the mi-crostructure and inertial characteristics of the substructure particles. More exactly, the flow and heat transport of micropolar ferrofluid over a stretching/shrinking sheet subjected to suction and injection is studied. Magnetite-Fe 3 O 4 (iron oxide) nanoparticles are considered in water taken as conventional base fluid. The mathematical model has been formulated based on Tiwari-Das nanofluid model. Explicit exact solutions of nonlinear coupled momentum equations are obtained. The solution of energy equation is obtained in terms of Whittaker function with the help of Maple. The impacts of pertinent parameters on velocity, micro-rotation velocity and temperature are shown graphically for positive and negative mass transfer flow and analyzed in detail. The results show that micro-rotation velocity increases first and then decreases. There is a remarkable change occurs to micro-rotation velocity for positive and negative values of mass transfer parameter. Presence of mass transfer parameter accelerate the profiles near the flow domain and then decelerates it. Further, micropolar ferrofluid have higher velocity than the classical nanofluid. Comparison have been made with published data under special cases and obtained in close agreement.

IEEE Journal of Translational Engineering in Health and Medicine, 2018

In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it ... more In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it passes through an individuals gastrointestinal (GI) tract. We obtain finite-difference time-domain and finite element method-based simulation results position assessment employing time of arrival (TOA). By means of a 3-D human body representation from a full-wave simulation software and lognormal models for TOA propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine, and large intestine. We present an investigation of the causes influencing localization precision, consisting of a range of organ properties; peripheral sensor array arrangements, number of pills in cooperation, and the random variations in transmit power of sensor nodes. We also perform a localization precision investigation for the situation where the transmission signal of the antenna is arbitrary with a known probability distribution. The computational solver outcome shows that the number of receiver antennas on the exterior of the body has higher impact on the precision of the location than the amount of capsules in collaboration within the GI region. The large intestine is influenced the most by the transmitter power probability distribution.

IberSPEECH 2018, 2018

Restricted Boltzmann Machines (RBMs) have been used both in the front-end and backend of speaker ... more Restricted Boltzmann Machines (RBMs) have been used both in the front-end and backend of speaker verification systems. In this work, we apply RBMs as a front-end in the context of speaker clustering. Speakers' utterances are transformed into a vector representation by means of RBMs. These vectors, referred to as RBM vectors, have shown to preserve speakerspecific information and are used for the task of speaker clustering. In this work, we perform the traditional bottom-up Agglomerative Hierarchical Clustering (AHC). Using the RBM vector representation of speakers, the performance of speaker clustering is improved. The evaluation has been performed on the audio recordings of Catalan TV Broadcast shows. The experimental results show that our proposed system outperforms the baseline i-vectors system in terms of Equal Impurity (EI). Using cosine scoring, a relative improvement of 11% and 12% are achieved for average and single linkage clustering algorithms respectively. Using PLDA scoring, the RBM vectors achieve a relative improvement of 11% compared to i-vectors for the single linkage algorithm.

Cureus, Jan 26, 2017

A significant but less recognized cause of ischemic stroke and transient ischemic attack (TIA) is... more A significant but less recognized cause of ischemic stroke and transient ischemic attack (TIA) is atherosclerosis of the vertebrobasilar system, which accounts for 20% of ischemic strokes. Pathology of the vertebrobasilar system can present significant challenges in determining the course of treatment. Due to the complexity of the vertebrobasilar system, there is slight disagreement about how to approach patients with atherosclerotic pathology of the posterior circulation. Two such approaches are either stenting of the vertebral or basilar artery or aggressive medical management. Here, we present the case of a 63-year-old male who presented with lightheadedness, diaphoresis, two episodes of loss of consciousness, and the abrupt onset of unilateral right-sided paresis. A computed tomography angiogram (CTA) of the head and neck demonstrated complex posterior circulation vertebrobasilar vascular stenosis and occlusions. There was an unstable clot located at the junction of the vertebra...

Cureus, 2017

Cervical nerve root avulsion is a well-documented result of motor vehicle collision (MVC), especi... more Cervical nerve root avulsion is a well-documented result of motor vehicle collision (MVC), especially when occurring at high velocities. These avulsions are commonly traction injuries of nerve roots that may be accompanied by a tear in the meninges through the vertebral foramina with associated collections of cerebrospinal fluid (CSF), thereby resulting in a pseudomeningocele. We present a case of a 19-year-old male who experienced an MVC and was brought to the emergency department (ED) with right arm paralysis and other injuries. A neurological examination demonstrated intact sensation but 0/5 muscle strength in the right upper extremity. A magnetic resonance imaging (MRI) of the spinal cord demonstrated massive epidural hematomas extending the length of the cervical spine caudally from C2. An MRI of the right brachial plexus showed C3-C7 anterior horn cell edema and associated traumatic nerve root avulsion with pseudomeningoceles on the right from C5-C8. The development of spinal cord hematoma with these injuries has rarely been documented in the literature and the multiple level avulsion described here with extensive hematoma is a rare clinical presentation. A literature review was conducted to determine the diagnostic requirements, treatment strategies, and complications of such an injury. Our patient received conservative treatment of the right brachial plexus injury and was transferred to an inpatient rehabilitation facility 13 days later.

International Journal of Modern Physics B

This research aims to study the 3D magnetohydrodynamics stagnation-point flow (SPF) over a horizo... more This research aims to study the 3D magnetohydrodynamics stagnation-point flow (SPF) over a horizontal plane surface (HPS) carrying water-based graphene oxide (GO) nanoparticles caused by an irregular heat source/sink used in heat transfer procedures. In addition, a Tiwari–Das model is used to inspect the dynamics of fluid flow behavior and heat transmission features of the nanoparticles with experiencing the impacts of thermal radiation. The acquired nonlinear set of partial differential equations (PDEs) is transfigured to a system of ordinary differential equations (ODEs) using similarity transformations. The accumulative dimensionless ODEs are then further tackled in MATLAB using the bvp4c solver. Tables and figures are prepared for the execution of several relevant constraints along with nodal/saddle indicative parameter, internal heat source/sink parameter, radiation parameter and nanoparticles volume fraction which divulges and clarify more accurately the posited quantitative d...

International Journal of Modern Physics B

Among several aspects, the one contributing towards the difficulty of groundwater quality evaluat... more Among several aspects, the one contributing towards the difficulty of groundwater quality evaluation is the large diversity of contamination sources. As contaminants comprising various compounds move from the soil to the water table, they will travel through several hydrologic zones. In constant unidirectional flow fields, a mathematical study of simultaneous adsorption and dispersion of a solute inside homogeneous and isotropic permeable media is described. The solute is adsorbed at a rate proportionate to its concentration in the dispersion systems, which are susceptible to input concentrations that fluctuate exponentially with time. The advection–dispersion equation (ADE) was solved numerically in this work to analyze the pollutants transport bearing in mind the coefficient of distribution and permeability by considering pollutant input concentrations. The solution is derived using the Laplace transform and Duhamel’s theorem with moving coordinates. For specified medium and fluid...

Frontiers of Earth Science, 2021

Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir c... more Surface and deep subsurface geological structural trends, stratigraphic features, and reservoir characteristics play important roles in assessment of hydrocarbon potential. Here, an approach that integrates digital elevation modelling, seismic interpretation, seismic attributes, three-dimensional (3D) geological structural modeling predicated on seismic data interpretation, and petrophysical analysis is presented to visualize and analyze reservoir structural trends and determine residual hydrocarbon potential. The digital elevation model is utilized to provide verifiable predictions of the Dhulian surface structure. Seismic interpretation of synthetic seismograms use twoway time and depth contour models to perform a representative 3D reservoir geological structure evaluation. Based on Petrel structural modeling efficiency, reservoir development indexes, such as the true 3D structural trends, slope, geometry type, depth, and possibility of hydrocarbon prospects, were calculated for the Eocene limestone Chorgali, upper Paleocene limestone Lockhart, early Permian arkosic sandstone Warcha, and Precambrian Salt Range formations. Trace envelope, instantaneous frequency, and average energy attribute analyses were utilized to resolve the spatial predictions of the subsurface structure, formation extrusion, and reflector continuity. We evaluated the average porosity, permeability, net to gross ratio, water saturation, and hydrocarbon saturation of early Eocene limestone and upper Paleocene limestone based on the qualitative interpretation of well log data. In summary, this integrated study validates 3D stratigraphic structural trends and fault networks, facilitates the residual hydrocarbon potential estimates, and reveals that the Dhulian area has a NE to SW (fold axis) thrust-bounded salt cored anticline structure, which substantiates the presence of tectonic compression. The thrust faults have fold axes trending from ENE to WSW, and the petrophysical analysis shows that the mapped reservoir is of good quality and has essential hydrocarbon potential, which can be exploited economically.

Lichen Planus first described by Erasmus Wilson in 1869 has moved from being regarded as an innoc... more Lichen Planus first described by Erasmus Wilson in 1869 has moved from being regarded as an innocuous benign condition to being considered as a potentially malignant disorder by the World Health Organization and is now defined as an idiopathic immune mediated mucocutaneous chronic inflammatory disease that affects the stratified squamous epithelia and the appendices. Oral lichen planus carries a very small probability of becoming malignant. The objective of the present study was to assess the long term prognostic aspects of oral squamous cell carcinoma/dysplasia and field cancerization occurring on the background of oral lichen planus in a retrospective analysis of 51 OLP patients (mean age=54 years; female, n=35; male, n=16) who between 2001 to middle of 2010 were diagnosed with OLP-related OSCC at the Department of Oral Medicine, Eastman Dental Institute and one major Head and Neck Cancer unit, University College London Hospital, United Kingdom. 1500 OLP patients were analyzed by ...

Biophysical Journal, 2021

Connexin-50 (Cx50) is among the most frequently mutated genes associated with congenital cataract... more Connexin-50 (Cx50) is among the most frequently mutated genes associated with congenital cataracts. While most of these disease-linked variants cause loss-of-function due to misfolding or aberrant trafficking, others directly alter channel properties. The mechanistic bases for such functional defects are mostly unknown. We investigated the functional and structural properties of a cataract-linked mutant, Cx50T39R (T39R), in the Xenopus oocyte system. T39R exhibited greatly enhanced hemichannel currents with altered voltage-gating properties compared to Cx50 and induced cell death. Coexpression of mutant T39R with wild-type Cx50 (to mimic the heterozygous state) resulted in hemichannel currents whose properties were indistinguishable from those induced by T39R alone, suggesting that the mutant had a dominant effect. Co-expression with Cx46 also produced channels with altered voltage-gating properties, particularly at negative potentials. All-atom molecular dynamics simulations indicate that the R39 substitution can form multiple electrostatic salt-bridge interactions between neighboring subunits that could stabilize the open-state conformation of the N-terminal domain, while also neutralizing the voltage-sensing residue D3 as well as residue E42 which participates in loop-gating. Together, these results suggest T39R acts as a dominant gain-of-function mutation that produces leaky hemichannels that may cause cytotoxicity in the lens and lead to development of cataracts. Statement of significance We investigated the functional and structural properties of a cataract-linked mutant, Cx50T39R (T39R), in the Xenopus oocyte system and showed that T39R exhibited greatly enhanced hemichannel currents with altered voltage-gating properties 3 compared to Cx50 and induced cell death. Consistent with our experimental findings, allatom equilibrium state molecular dynamics (MD) simulations of T39R show that R39 stabilized the open-state configuration of the N-terminal (NT) domain from an adjacent subunit. These results suggest that T39R causes disease by preventing the hemichannels from closing when present in the plasma membrane in the undocked state and provide an atomistic rationalization for the Cx50 disease-linked phenotype. They also expand our understanding of how connexin hemichannel channel gating is controlled.

Chinese Journal of Physics, 2021

International Journal of Numerical Methods for Heat & Fluid Flow, 2021

Purpose The boundary-layer analysis is required to reveal the fluid flow behavior in several indu... more Purpose The boundary-layer analysis is required to reveal the fluid flow behavior in several industrial processes and enhance the products’ effectiveness. Therefore, this research aims to investigate the buoyancy or mixed convective stagnation-point flow (SPF) and heat transfer of a micropolar fluid filled with hybrid nanoparticles over a vertical plate. The nanoparticles silver (Ag) and titanium dioxide (TiO2) are scattered into various base fluids to form a new-fangled class of (Ag-TiO2/various base fluid) hybrid nanofluid along with different shape factors. Design/methodology/approach The self-similarity transformations are used to reformulate the leading requisite partial differential equations into renovated non-linear dimensionless ordinary differential equations. The numerical dual solutions are gained for the transmuted requisite equations with the help of the bvp4c built-in package in MATLAB software. The results are validated by comparing them with previously available pub...

The European Physical Journal Applied Physics, 2020

The current study investigates MHD natural convection heat transfer of a hybrid nanofluid in a tr... more The current study investigates MHD natural convection heat transfer of a hybrid nanofluid in a truncated cone along with transparent domains having the stimulus of an inherent constant magnetic field. The governing equations subject to the physical boundary conditions are solved numerically by using the Galerkin finite element method. The effects of the various parameters involved in the problem such as the Rayleigh number Ra (ranging between 103 and 106), the Hartmann number Ha (ranging between 0 and 60), and the porosity ratio ε (0.1–0.9) are examined. Moreover, the effects of Da which represents the Darcy number (between 10‑3 and 10‑1) and the volume fraction of nanoparticles ϕ for the dissipated nanoparticles of Al2O3-Cu are reported in terms of the streamlines and isotherms distributions as well as the Nusselt number. Such parameters are critical control parameters for both the fluid flow and the rate of heat transfer of the natural convection in the annular space. The solution...

Case Studies in Thermal Engineering, 2021

Nanoliquid is a modern invention that is very promising in improving the heat transfer capabiliti... more Nanoliquid is a modern invention that is very promising in improving the heat transfer capabilities. The most critical disadvantage of classical nanoliquid models is that they cannot express categories of liquids that have definite microscopic characteristics that occur from the local structure and micro-rotation of the fluid elements. In this article, the features of the microrotation and heat transfer characteristics of a micropolar hybrid nanofluid flow towards a stagnation point on a stretching/shrinking sheet are analyzed numerically. The similarity transformation is utilized to transform the governing equations to a set of nonlinear ordinary differential equations before they are solved numerically using the function bvp4c in MATLAB software. The dual nature of solutions of shear stress, heat transfer, and micro-rotation gradient are illustrated for a broad range of pertaining parameters. The separation of boundary-layer takes place when multiple results fail to happen beyond a critical value of the shrinking parameter. The outcomes show that the separation of boundary layer is delayed due to mass suction parameter while the contrary behavior is observed for the effects of the volume fraction of nanoparticles. In addition, the friction factor initially uplifts and then declines due to suction for the first solution, while decelerates for the second solution but the heat transport and micro-rotation gradient enhance due to suction for both solutions. The temperature augments for both solution branches due to nanoparticles volume fraction while the micro-rotation and the velocity shrink for the first solution branch while uplift for the lower solution branch.

Journal of Molecular Liquids, 2021

Abstract The time-dependent stagnation point flow (SPF) and heat transfer of a water-based hybrid... more Abstract The time-dependent stagnation point flow (SPF) and heat transfer of a water-based hybrid nanofluid (Cu − Al2O3/Water) from a radially permeable shrinking or stretching surface is examined. The similarity technique is employed to transform the governing equations of hybrid nanofluid (Cu − Al2O3/Water) into similarity equations. These similarity equations are solved numerically using bvp4c function in MATLAB software. The numerical outcomes are acquired for particular values of the selected parameters. The results notice that dual solutions exist, up to a definite amount of the suction, unsteady strengths, and nanoparticle volume fraction. The critical amount declines due to nanoparticle volume fraction and augments due to suction and unsteady parameters. Also, it is seen that hybrid nanofluid (Cu − Al2O3/Water) augments the rate of heat transfer relative to the regular fluid. The temporal stability analysis is implemented to determine the stability of the dual solutions, and it is found that only one of them is stable and thus physically reliable as time passes.

Crystals, 2020

The current framework tackles the buoyancy flow via a slender revolution bodies comprising Molybd... more The current framework tackles the buoyancy flow via a slender revolution bodies comprising Molybdenum-Disulfide Graphene Oxide generalized hybrid nanofluid embedded in a porous medium. The impact of radiation is also provoked. The outcomes are presented in this analysis to examine the behavior of hybrid nanofluid flow (HNANF) through the cone, the paraboloid, and the cylinder-shaped bodies. The opposing flow (OPPF) as well as the assisting flow (ASSF) is discussed. The leading flow equations of generalized hybrid nanoliquid are worked out numerically by utilizing bvp4c solver. This sort of the problem may meet in the automatic industries connected to geothermal and geophysical applications where the sheet heat transport occurs. The impacts of engaging controlled parameters of the transmuted system on the drag force and the velocity profile are presented through the graphs and tables. The achieved outcomes suggest that the velocity upsurges due to the dimensionless radius of the slen...

Frontiers in Chemistry, 2020

Nisar et al. Mixed Squeezing Flow of Hybrid Ferroparticles augments due to the volume fraction of... more Nisar et al. Mixed Squeezing Flow of Hybrid Ferroparticles augments due to the volume fraction of nanoparticles in the assisting flow and declines in the opposing flow, while the opposite direction is noticed in the temperature field.

Processes, 2019

Entropy generation and dual solutions are rarely studied in the literature. An analysis is attemp... more Entropy generation and dual solutions are rarely studied in the literature. An analysis is attempted here. More exactly, the present paper looks at the impact of radiation of a micropolar fluid on mixed convective flow containing the titanium alloy Ti6Al4V nanoparticle along with a Riga plate. The study of dual-nature solution for the entropy generation along a Riga surface was not being explored in the literature; therefore, the current model focuses on the dual solutions of this complex nature model. Riga surface is identified as an actuator of electromagnetic in which electrodes are accumulated alternatively. This array produces the behavior of electromagnetic hydrodynamic in the flow field. The transmuted leading equations were worked out through the formula of 3-stage Lobatto IIIA. Influences of exercising enormous parameters on temperature distribution, velocity, and micro rotation fields are portrayed and argued. More than one solution is achieved in opposing flow, while in t...

Processes, 2019

A mathematical model comprising Darcy Forchheimer effects on the 3D nanofluid flow with engine oi... more A mathematical model comprising Darcy Forchheimer effects on the 3D nanofluid flow with engine oil as a base fluid containing suspended carbon nanotubes (CNTs) is envisioned. The CNTs are of both types i.e., multi-wall carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). The flow is initiated by an exponentially stretched surface. The impacts of Cattaneo–Christov heat flux along with velocity and thermal slip conditions are key factors in the novelty of the defined model. The boundary layer notion is designed to convert the compact form of equations into the component shape. Appropriate transformations lead to differential equations with high nonlinearity. The final non-dimensional system is solved numerically by a “MATLAB” function known as bvp4c. For both CNTs, different graphical sketches are drawn to present the influence of arising parameters versus related profiles. The outcomes show that higher slip parameter boosts the axial velocity, whereas fluid temperat...

Journal of Molecular Liquids, 2018

Nanofluid is the most promising gift of modern science to improve the heat transfer capabilities ... more Nanofluid is the most promising gift of modern science to improve the heat transfer capabilities of conventional heat transfer fluids. However, one of the most crucial drawbacks for classical nanofluid models is that they cannot describe a class of fluids that have certain microscopic characters arising from the micro-rotation and local structure of the fluid elements. In this work, the innovative micropolar nanofluid model is introduced to study the mi-crostructure and inertial characteristics of the substructure particles. More exactly, the flow and heat transport of micropolar ferrofluid over a stretching/shrinking sheet subjected to suction and injection is studied. Magnetite-Fe 3 O 4 (iron oxide) nanoparticles are considered in water taken as conventional base fluid. The mathematical model has been formulated based on Tiwari-Das nanofluid model. Explicit exact solutions of nonlinear coupled momentum equations are obtained. The solution of energy equation is obtained in terms of Whittaker function with the help of Maple. The impacts of pertinent parameters on velocity, micro-rotation velocity and temperature are shown graphically for positive and negative mass transfer flow and analyzed in detail. The results show that micro-rotation velocity increases first and then decreases. There is a remarkable change occurs to micro-rotation velocity for positive and negative values of mass transfer parameter. Presence of mass transfer parameter accelerate the profiles near the flow domain and then decelerates it. Further, micropolar ferrofluid have higher velocity than the classical nanofluid. Comparison have been made with published data under special cases and obtained in close agreement.

IEEE Journal of Translational Engineering in Health and Medicine, 2018

In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it ... more In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it passes through an individuals gastrointestinal (GI) tract. We obtain finite-difference time-domain and finite element method-based simulation results position assessment employing time of arrival (TOA). By means of a 3-D human body representation from a full-wave simulation software and lognormal models for TOA propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine, and large intestine. We present an investigation of the causes influencing localization precision, consisting of a range of organ properties; peripheral sensor array arrangements, number of pills in cooperation, and the random variations in transmit power of sensor nodes. We also perform a localization precision investigation for the situation where the transmission signal of the antenna is arbitrary with a known probability distribution. The computational solver outcome shows that the number of receiver antennas on the exterior of the body has higher impact on the precision of the location than the amount of capsules in collaboration within the GI region. The large intestine is influenced the most by the transmitter power probability distribution.

IberSPEECH 2018, 2018

Restricted Boltzmann Machines (RBMs) have been used both in the front-end and backend of speaker ... more Restricted Boltzmann Machines (RBMs) have been used both in the front-end and backend of speaker verification systems. In this work, we apply RBMs as a front-end in the context of speaker clustering. Speakers' utterances are transformed into a vector representation by means of RBMs. These vectors, referred to as RBM vectors, have shown to preserve speakerspecific information and are used for the task of speaker clustering. In this work, we perform the traditional bottom-up Agglomerative Hierarchical Clustering (AHC). Using the RBM vector representation of speakers, the performance of speaker clustering is improved. The evaluation has been performed on the audio recordings of Catalan TV Broadcast shows. The experimental results show that our proposed system outperforms the baseline i-vectors system in terms of Equal Impurity (EI). Using cosine scoring, a relative improvement of 11% and 12% are achieved for average and single linkage clustering algorithms respectively. Using PLDA scoring, the RBM vectors achieve a relative improvement of 11% compared to i-vectors for the single linkage algorithm.

Cureus, Jan 26, 2017

A significant but less recognized cause of ischemic stroke and transient ischemic attack (TIA) is... more A significant but less recognized cause of ischemic stroke and transient ischemic attack (TIA) is atherosclerosis of the vertebrobasilar system, which accounts for 20% of ischemic strokes. Pathology of the vertebrobasilar system can present significant challenges in determining the course of treatment. Due to the complexity of the vertebrobasilar system, there is slight disagreement about how to approach patients with atherosclerotic pathology of the posterior circulation. Two such approaches are either stenting of the vertebral or basilar artery or aggressive medical management. Here, we present the case of a 63-year-old male who presented with lightheadedness, diaphoresis, two episodes of loss of consciousness, and the abrupt onset of unilateral right-sided paresis. A computed tomography angiogram (CTA) of the head and neck demonstrated complex posterior circulation vertebrobasilar vascular stenosis and occlusions. There was an unstable clot located at the junction of the vertebra...

Cureus, 2017

Cervical nerve root avulsion is a well-documented result of motor vehicle collision (MVC), especi... more Cervical nerve root avulsion is a well-documented result of motor vehicle collision (MVC), especially when occurring at high velocities. These avulsions are commonly traction injuries of nerve roots that may be accompanied by a tear in the meninges through the vertebral foramina with associated collections of cerebrospinal fluid (CSF), thereby resulting in a pseudomeningocele. We present a case of a 19-year-old male who experienced an MVC and was brought to the emergency department (ED) with right arm paralysis and other injuries. A neurological examination demonstrated intact sensation but 0/5 muscle strength in the right upper extremity. A magnetic resonance imaging (MRI) of the spinal cord demonstrated massive epidural hematomas extending the length of the cervical spine caudally from C2. An MRI of the right brachial plexus showed C3-C7 anterior horn cell edema and associated traumatic nerve root avulsion with pseudomeningoceles on the right from C5-C8. The development of spinal cord hematoma with these injuries has rarely been documented in the literature and the multiple level avulsion described here with extensive hematoma is a rare clinical presentation. A literature review was conducted to determine the diagnostic requirements, treatment strategies, and complications of such an injury. Our patient received conservative treatment of the right brachial plexus injury and was transferred to an inpatient rehabilitation facility 13 days later.