3,638 research outputs found
Consumer Preferences in Cyberspace : a Comparison of Websites Ranking Across the Globe.
No full textColor poster with text, charts, and graphs describing research conducted by Piyush Gupta, advised by Bruce W. N. Lo.To market their products and/or services globally, transnational corporations are often faced with the question of to what extent they need to tailor their marketing message and their commodities to local culture and regional norms.
The challenge is whether to globalize or to localize. This study attempts to examine this dichotomy from a macro angle by observing international e-commerce websites.University of Wiconsin--Eau Claire Office of Research and Sponsored Programs
Synthesis and characterization of biocompatible bimetallic-semi-aromatic polyester hybrid nanocomposite
No full textFunding Information: Dr. Piyush Kumar Gupta is thankful to the Department of Life Sciences, Sharda University, Greater Noida, India for providing infrastructure and research facilities. Publisher Copyright: © 2021 Elsevier B.V.Nanocomposites have been broadly used in bioelectronic, biosensing, photocatalytic, and bioimaging. Moreover, its use in bioengineering field is emerging continuously. The present study reports first-time the synthesis of a novel bimetallic-semi-aromatic polyester hybrid nanocomposite. The obtained MnFe2O4-poly(tBGE-alt-PA) hybrid nanocomposite was physicochemically characterized. FTIR analysis confirmed the synthesis of hybrid nanocomposite. XRD data showed the crystal nature of hybrid nanocomposite due to MnFe2O4 nanoparticles (NPs). TGA study presented the thermostable nature of hybrid nanocomposite and DSC analysis exhibited the absence of chemical interactions between the copolymer and MnFe2O4 NPs in hybrid nanocomposite. Further, the net negative charge was measured on the surface of this almost spherical hybrid nanocomposite. Later, we observed the biocompatible and hemocompatible nature of nanocomposite and in future, it may open many novel avenues in various fields of biomedical science.Peer reviewe
A generalized finite element method for the simulation of non-planar three-dimensional hydraulic fracture propagation
No full textHydraulic fractures are a class of tensile fractures that occur in brittle and quasi-brittle materials due to the injection of a viscous fluid. Hydraulic fractures occur both naturally and created deliberately for engineering applications. In the oil and gas industry, it is a preferred method to enhance the recovery of hydrocarbons by creation of permeable pathways. A successful hydraulic fracturing treatment may increase the production tens of times, making the technique economically attractive. Yet, there are concerns about the environmental impact of the toxic fluids used in reservoir treatment. The potential of groundwater contamination from the hydraulic fracturing treatments has been one of the major roadblocks for its rapid development. One of the main reasons for this concern is the lack of a thorough understanding of induced hydraulic fracture propagation. With the advent of real-time monitoring techniques fully three-dimensional models that can be used to update treatment designs in real time as information is fed back into the models.
Typically, hydraulic fracturing of low-permeability shale reservoirs involves modeling of three coupled processes: (i) the mechanical deformation of the rock induced by the applied fluid pressure on fracture faces; (ii) the flow of viscous fracturing fluid in the fracture; and (iii) the fracture propagation in the rock from the induced hydraulic loading. Additional difficulties in modeling of this already challenging problem are, for example, change in magnitude and/or orientation of the in-situ confining stresses, presence of a nearby natural fracture/fault, transport of suspended proppant particles within the fracture etc.
In this work, we develop a fully-coupled system of equations for modeling non-planar three-dimensional hydraulic fracture propagation with a Generalized/Extended Finite Element Method (G/XFEM). This method greatly facilitates the discretization of complex 3-D fractures since the finite element mesh is not required to fit the crack surface(s). Adaptive surface triangulations are used to represent complex 3-D fracture surfaces. Such explicit surface representation retains the finer and complex details of the fracture, thus providing a high fidelity numerical simulation. The proposed coupled formulation does not make any assumptions about the geometry of the solid domain or the fracture surface except that the fracture geometry is such that the fluid flow in the fracture can be modeled using the Reynolds lubrication equation. A modified Newton – Raphson algorithm to solve the nonlinear system of coupled equations is also developed.
The stress and pressure singularities of the solution of hydraulic fracturing problems require adaptive mesh refinement for efficient discretization error control. Dealing with adaptive mesh refinement in time-dependent problems is challenging for any method. This is typically handled through mappings of solutions at every time step. In this work, we avoid volume mappings by taking advantage of the explicit representation of the crack surface geometry adopted in the GFEM. This allows the use of completely different meshes at every time step and is much less computationally demanding than volume mappings.
One of the main challenges in hydraulic fracture propagation is satisfying the Irwin’s criterion for fracture propagation. In this work, we propose a new fracture propagation model, named GD model, based on a regularization of Irwin’s criterion for brittle materials. Utilizing the proposed fracture model, a fully automated adaptive non-linear solution algorithm using the coupled hydro–mechanical formulation for hydraulic fracture propagation is also presented. The proposed algorithm is computationally efficient by automatically computing the time step increment at each fracture propagation step using the solution history.
An energy based predictor-corrector algorithm for the fully automatic simulation of the fracture growth in three-dimensional linear elastic fracture mechanics (LEFM) problems is also proposed. The effects of dominant in-situ stresses, orientation of wellbore, rock toughness on fracture propagation, and interaction of hydraulic fracture with wellbore are studied in detail in this work. The proposed GFEM is also utilized to study the effects of wellbore modeling, near-wellbore tortuosity and interaction of multiple hydraulic fractures.
The accuracy and the efficiency of the proposed coupled formulation and algorithms is accessed on various representative, large-scale examples.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-07-07 without embargo termsThe student, Piyush Gupta, accepted the attached license on 2016-04-13 at 15:32.The student, Piyush Gupta, submitted this Dissertation for approval on 2016-04-13 at 15:43.This Dissertation was approved for publication on 2016-04-14 at 16:39.DSpace SAF Submission Ingestion Package generated from Vireo submission #9209 on 2016-07-07 at 13:30:31Made available in DSpace on 2016-07-07T19:53:49Z (GMT). No. of bitstreams: 3
GUPTA-DISSERTATION-2016.pdf: 53130756 bytes, checksum: 828d8cdfc09a409b0d89bb7d53b0c4b6 (MD5)
LICENSE.txt: 4209 bytes, checksum: 11557193d73271df06faccd4bfd077d0 (MD5)
PROQUEST_LICENSE.txt: 4555 bytes, checksum: bafde95302e38e4d319b9d9b8266486f (MD5)
Previous issue date: 2016-04-1
Premature polyadenylation of MAGI3 is associated with diminished N[superscript 6]-methyladenosine in its large internal exon
No full textIn cancer, tumor suppressor genes (TSGs) are frequently truncated, causing their encoded products to be non-functional or dominant-negative. We previously showed that premature polyadenylation (pPA) of MAGI3 truncates the gene, switching its functional role from a TSG to a dominant-negative oncogene. Here we report that MAGI3 undergoes pPA at the intron immediately downstream of its large internal exon, which is normally highly modified by N[superscript 6]-methyladenosine (m[superscript 6]A). In breast cancer cells that upregulate MAGI3[superscript pPA], m[superscript 6]A levels in the large internal exon of MAGI3 are significantly reduced compared to cells that do not express MAGI3[superscript pPA]. We further find that MAGI3[superscript pPA] transcripts are significantly depleted of m[superscript 6]A modifications, in contrast to highly m6A-modified full-length MAGI3 mRNA. Finally, we analyze public expression data and find that other TSGs, including LATS1 and BRCA1, also undergo intronic pPA following large internal exons, and that m[superscript 6]A levels in these exons are reduced in pPA-activated breast cancer cells relative to untransformed mammary cells. Our study suggests that m6A may play a role in regulating intronic pPA of MAGI3 and possibly other TSGs, warranting further investigation
The endoplasmic reticulum may be an Achilles' heel of cancer cells that have undergone an epithelial-to-mesenchymal transition
No full textIn a recent report published in Cancer Discovery we identified a novel vulnerability of cancer cells that have undergone an epithelial–mesenchymal transition (EMT) and established that the PERK branch of the unfolded protein response is constitutively activated upon EMT. In this commentary, we summarize and provide context for our findings. Keywords: EMT; ER stress; UPRNational Science Foundation (U.S.) (Grant 1122374
A Randomized, Controlled Trial Comparing Tearcare® and Cyclosporine Ophthalmic Emulsion for the Treatment of Dry Eye Disease (SAHARA) [Letter]
No full textSuraj Kumar Chaurasiya,1 Mahendra Singh,1 Piyush Kohli2 1Department of Optometry and Vision Science, CL Gupta Eye Institute, Moradabad, UP, 244001, India; 2Department of Ophthalmology, Vitreo-Retina, CL Gupta Eye Institute, Moradabad, UP, 244001, IndiaCorrespondence: Mahendra Singh, CL Gupta Eye Institute, Ram Ganga Vihar Phase II (Extn.), Moradabad, UP, 244001, India, Tel +91-6395586269, Email [email protected]
Current trends in bio-waste mediated metal/metal oxide nanoparticles for drug delivery
No full textFunding Information: B.H. Jaswanth Gowda is thankful to Yenepoya (Deemed to be University), Mangalore, India for providing the research fellowship. Dr. Piyush Kumar Gupta is thankful to the Department of Life Sciences, School of Basic Sciences and Research, Sharda University, for providing the infrastructure and research facilities. Kavindra Kumar Kesari is thankful to Aalto University for providing an open access support. Publisher Copyright: © 2022 The AuthorsNanoparticles have received much attention in biomedical applications due to their unique physicochemical properties. The metal/metal oxide nanoparticles are involved in various applications, including drug delivery, therapy, and diagnosis. Subsequently, many hazardous chemicals and organic solvents were utilized to synthesize the metallic nanoparticles. Therefore, the green synthesis came into the limelight to overcome the economic and environmental burden. The green synthesis represents the production of nanoparticles that reduce or terminate the use of hazardous materials and solvents that encourages environmental safety. The frequently utilized green materials in numerous metallic nanoparticle syntheses include microbes, plants, pizza, and other food sources. However, the burden on global food security and limited natural resources creates distress over environmental sustainability. Thus, adopting bio-waste materials to produce highly efficient, biocompatible, economic, and eco-friendly metallic nanoparticles could support waste valorization and lead to environmental sustainability. Therefore, the present review focuses on the various bio-waste materials adopted to synthesize metal/metal oxide nanoparticles. We have thoroughly discussed the potential of chemicals-mediated metal/metal oxide nanoparticles in different drug delivery applications such as tumor targeting, brain targeting, stimuli-responsive drug release followed by large molecules delivery. Consequently, this can open a new road for researchers to explore drug delivery applications using bio-waste mediated green synthesized metallic nanoparticles. Finally, the cytotoxicity aspects of such nanoparticles are meticulously discussed compared to chemically synthesized counterparts.Peer reviewe
Cancer cells exhibit clonal diversity in phenotypic plasticity
No full textPhenotypic heterogeneity in cancers is associated with invasive progression and drug resistance. This heterogeneity arises in part from the ability of cancer cells to switch between phenotypic states, but the dynamics of this cellular plasticity remain poorly understood. Here we apply DNA barcodes to quantify and track phenotypic plasticity across hundreds of clones in a population of cancer cells exhibiting epithelial or mesenchymal differentiation phenotypes. We find that the epithelial-to-mesenchymal cell ratio is highly variable across the different clones in cancer cell populations, but remains stable for many generations within the progeny of any single clone - with a heritability of 0.89. To estimate the effects of combination therapies on phenotypically heterogeneous tumours, we generated quantitative simulations incorporating empirical data from our barcoding experiments. These analyses indicated that combination therapies which alternate between epithelial- and mesenchymal-specific treatments eventually select for clones with increased phenotypic plasticity. However, this selection could be minimized by increasing the frequency of alternation between treatments, identifying designs that may minimize selection for increased phenotypic plasticity. These findings establish new insights into phenotypic plasticity in cancer, and suggest design principles for optimizing the effectiveness of combination therapies for phenotypically heterogeneous tumours.National Science Foundation (U.S.) (Grant 1122374)National Institutes of Health (U.S.) (Grant 2T32GM007287-36
- …
