152 results match your criteria: "McCormick School of Engineering and Applied Science[Affiliation]"

Robust and tunable performance of a cell-free biosensor encapsulated in lipid vesicles.

Sci Adv

January 2023

Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, USA.

Cell-free systems have enabled the development of genetically encoded biosensors to detect a range of environmental and biological targets. Encapsulation of these systems in synthetic membranes to form artificial cells can reintroduce features of the cellular membrane, including molecular containment and selective permeability, to modulate cell-free sensing capabilities. Here, we demonstrate robust and tunable performance of a transcriptionally regulated, cell-free riboswitch encapsulated in lipid membranes, allowing the detection of fluoride, an environmentally important molecule.

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On cheap entropy-sparsified regression learning.

Proc Natl Acad Sci U S A

January 2023

Institute of Human Genetics, University Medical Center Johannes Gutenberg-Universität (JGU) Mainz, Anselm-Franz-von-Bentzel-Weg 3 55128, Mainz, Germany.

Regression learning is one of the long-standing problems in statistics, machine learning, and deep learning (DL). We show that writing this problem as a probabilistic expectation over (unknown) feature probabilities - thus increasing the number of unknown parameters and seemingly making the problem more complex-actually leads to its simplification, and allows incorporating the physical principle of entropy maximization. It helps decompose a very general setting of this learning problem (including discretization, feature selection, and learning multiple piece-wise linear regressions) into an iterative sequence of simple substeps, which are either analytically solvable or cheaply computable through an efficient second-order numerical solver with a sublinear cost scaling.

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A combination microparticle strategy for achieving antigen-specific tolerance.

Proc Natl Acad Sci U S A

December 2022

John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.

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Impact of assuming a circular orifice on flow error through elliptical regurgitant orifices: computational fluid dynamics and in vitro analysis of proximal flow convergence.

Int J Cardiovasc Imaging

February 2023

Division of Cardiology, Department of Medicine, Bluhm Cardiovascular Institute, Feinberg School of Medicine, Northwestern University, 676 N. St. Claire Street, Suite 600, Chicago, IL, 60611, USA.

Grounded in hydrodynamic theory, proximal isovelocity surface area (PISA) is a simplistic and practical technique widely used to quantify valvular regurgitation flow. PISA provides a relatively reasonable, though slightly underestimated flow rate for circular orifices. However, for elliptical orifices frequently seen in functional mitral regurgitation, PISA underestimates the flow rate.

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Transcranial Magnetic Stimulation (TMS) can be used to modulate cortico-spinal excitability following a paired associative stimulation (PAS) protocol. Movement-related cortical stimulation (MRCS) is a PAS protocol based on the synchronization of a single-pulse TMS with a movement task. However, plasticity and motor performance potentiation due to MRCS has been related exclusively to single-movement tasks.

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Selectivity in Enzymatic Phosphorus Recycling from Biopolymers: Isotope Effect, Reactivity Kinetics, and Molecular Docking with Fungal and Plant Phosphatases.

Environ Sci Technol

November 2022

Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, United States.

Among ubiquitous phosphorus (P) reserves in environmental matrices are ribonucleic acid (RNA) and polyphosphate (polyP), which are, respectively, organic and inorganic P-containing biopolymers. Relevant to P recycling from these biopolymers, much remains unknown about the kinetics and mechanisms of different acid phosphatases (APs) secreted by plants and soil microorganisms. Here we investigated RNA and polyP dephosphorylation by two common APs, a plant purple AP (PAP) from sweet potato and a fungal phytase from .

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Corrigendum: Functional mobility training with a powered knee and ankle prosthesis.

Front Rehabil Sci

August 2022

Shirley Ryan AbilityLab, Chicago, IL, United States.

[This corrects the article DOI: 10.3389/fresc.2022.

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Thyroid cancer is the most common endocrine malignancy with an increasing incidence over the past few years. Surgery is considered the primary therapeutic option, which often involves lymph node dissection. The aim of this study was to assess the role of carbon nanoparticles, a novel agent, in thyroid cancer surgery.

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Bridging the electrode-neuron gap: finite element modeling of in vitro neurotrophin gradients to optimize neuroelectronic interfaces in the inner ear.

Acta Biomater

October 2022

Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Simpson Querrey Institute, Chicago IL, 60611, USA; Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, School of Communication, Northwestern University, Evanston, IL 60201, USA; The Hugh Knowles Center for Clinical and Basic Science in Hearing and its Disorders, Evanston, IL 60201, USA; Center for Advanced Regenerative Engineering, Evanston, IL 60201, USA. Electronic address:

Although cochlear implant (CI) technology has allowed for the partial restoration of hearing over the last few decades, persistent challenges (e.g., poor performance in noisy environments and limited ability to decode intonation and music) remain.

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Metabolomics analysis of unresolved molecular variability in stoichiometry dynamics of a stream dissolved organic matter.

Water Res

September 2022

Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL 60208, United States. Electronic address:

Broad molecular classification based on stoichiometric ratio relationships has been used extensively to characterize the chemical diversity of aquatic dissolved organic matter (DOM). However, variability in the molecular composition within this classification has remained elusive, thus limiting the interpretation of DOM dynamics, especially with respect to transport versus transformation patterns in response to hydrologic or landscape changes. Here, leveraging high-frequency spatiotemporal sampling during rainfall events at a Critical Zone Observatory project site in Clear Creek, Iowa, we apply a metabolomics-based analysis validated with fragmentation using tandem mass spectrometry to uncover patterns in the molecular features of the DOM composition that were not resolved by classification based on stoichiometric ratios in the chemical formulae.

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Bending Rigidity, Capacitance, and Shear Viscosity of Giant Vesicle Membranes Prepared by Spontaneous Swelling, Electroformation, Gel-Assisted, and Phase Transfer Methods: A Comparative Study.

Langmuir

August 2022

Department of Engineering Sciences and Applied Mathematics, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, United States.

Closed lipid bilayers in the form of giant unilamellar vesicles (GUVs) are commonly used membrane models. Various methods have been developed to prepare GUVs, however it is unknown if all approaches yield membranes with the same elastic, electric, and rheological properties. Here, we combine flickering spectroscopy and electrodefomation of GUVs to measure, at identical conditions, membrane capacitance, bending rigidity and shear surface viscosity of palmitoyloleoylphosphatidylcholine (POPC) membranes formed by several commonly used preparation methods: thin film hydration (spontaneous swelling), electroformation, gel-assisted swelling using poly(vinyl alcohol) (PVA) or agarose, and phase-transfer.

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Background: Large vessel vasculitis (LVV) can be characterized based on symptom severity, and this characterization helps clinicians decide upon treatment approach. Our aim was to compare the imaging findings of combined modality positron emission tomography/magnetic resonance (PET/MR) and inflammatory markers between severe and non-severe LVV. A retrospective query was performed to identify all patients with LVV who underwent PET/MR at our institution between January 2015 and January 2021.

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Progress on Designing a Chemical Retinal Prosthesis.

Front Cell Neurosci

June 2022

Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States.

The last major review of progress toward a chemical retinal prosthesis was a decade ago. Many important advancements have been made since then with the aim of producing an implantable device for animal testing. We review that work here discussing the potential advantages a chemical retinal prosthesis may possess, the spatial and temporal resolutions it might provide, the materials from which an implant might be constructed and its likely effectiveness in stimulating the retina in a natural fashion.

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Dynamic utilization of low-molecular-weight organic substrates across a microbial growth rate gradient.

J Appl Microbiol

September 2022

Soil and Crop Sciences, School of Integrative Plant Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, USA.

Aim: Low-molecular-weight organic substances (LMWOSs) are at the nexus between micro-organisms, plant roots, detritus, and the soil mineral matrix. The nominal oxidation state of carbon (NOSC) has been suggested as a potential parameter for modelling microbial uptake rates of LMWOSs and the efficiency of carbon incorporation into new biomass.

Methods And Results: In this study, we assessed the role of compound class and oxidation state on uptake kinetics and substrate-specific carbon use efficiency (SUE) during the growth of three model soil micro-organisms, a fungal isolate (Penicillium spinulosum) and two bacterial isolates (Paraburkholderia solitsugae, and Ralstonia pickettii).

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Strategies of organic phosphorus recycling by soil bacteria: acquisition, metabolism, and regulation.

Environ Microbiol Rep

February 2022

Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, 60208, USA.

Critical to meeting cellular phosphorus (P) demand, soil bacteria deploy a number of strategies to overcome limitation in inorganic P (P ) in soils. As a significant contributor to P recycling, soil bacteria secrete extracellular enzymes to degrade organic P (P ) in soils into the readily bioavailable P . In addition, several P compounds can be transported directly via specific transporters and subsequently enter intracellular metabolic pathways.

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Background: Gadobutrol (GB) and gadoterate meglumine (GM) are contrast agents used for contrast-enhanced magnetic resonance angiography (CEMRA). Supraaortic vasculature (SAV) CEMRAs are used to evaluate stroke risk and neurologic symptoms. There is a need to compare the SAV CEMRA image quality obtained with GB and GM.

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Effects of Phosphonate Herbicides on the Secretions of Plant-Beneficial Compounds by Two Plant Growth-Promoting Soil Bacteria: A Metabolomics Investigation.

ACS Environ Au

March 2022

Department of Chemical and Biological Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, United States.

Plant growth-promoting rhizobacteria (PGPR) that colonize plant roots produce a variety of plant-beneficial compounds, including plant-growth regulators, metal-scavenging compounds, and antibiotics against plant pathogens. Adverse effects of phosphonate herbicides, the most extensively used herbicides, on the growth and metabolism of PGPR species have been widely reported. However, the potential consequence of these effects on the biosynthesis and secretion of PGPR-derived beneficial compounds still remains to be investigated.

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Early identification of atypical infant movement behaviors consistent with underlying neuromotor pathologies can expedite timely enrollment in therapeutic interventions that exploit inherent neuroplasticity to promote recovery. Traditional neuromotor assessments rely on qualitative evaluations performed by specially trained personnel, mostly available in tertiary medical centers or specialized facilities. Such approaches are high in cost, require geographic proximity to advanced healthcare resources, and yield mostly qualitative insight.

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Polyphosphate-accumulating organisms (PAOs), which can store high levels of phosphate (P) in the form of polyphosphate (polyP), are employed to engineer enhanced biological P removal (EBPR) from wastewaters. Co-localization of Mg and K in polyP granules of PAOs has been reported, and higher abundance of Mg-polyP granules relative to other metal complexes was correlated positively with EBPR performance stability. However, the underlying mechanism remains unknown.

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To accelerate compressed sensing (CS) reconstruction of subsampled radial k-space data using a geometrically-derived density compensation function (gDCF) without significant loss in image quality.We developed a theoretical framework to calculate a gDCF based on Nyquist distance along the radial and circumferential directions of a discrete polar coordinate system. Our gDCF was compared against standard DCF (e.

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Tissue phase mapping (TPM) is an MRI technique for quantification of regional biventricular myocardial velocities. Despite its potential, clinical use is limited due to the requisite labor-intensive manual segmentation of cardiac contours for all time frames. The purpose of this study was to develop a deep learning (DL) network for automated segmentation of TPM images, without significant loss in segmentation and myocardial velocity quantification accuracy compared with manual segmentation.

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In this study, integrated experimental tests and computational modeling are proposed to investigate the failure mechanisms of open-hole cross-ply carbon fiber reinforced polymer (CFRP) laminated composites. In particular, we propose two effective methods, which include width-tapered double cantilever beam (WTDCB) and fixed-ratio mixed-mode end load split (FRMMELS) tests, to obtain the experimental data more reliably. We then calibrate the traction-separation laws of cohesive zone model (CZM) used among laminas of the composites by leveraging these two methods.

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EPA and DHA differentially modulate membrane elasticity in the presence of cholesterol.

Biophys J

June 2021

Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois; Center for Synthetic Biology, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois. Electronic address:

Polyunsaturated fatty acids (PUFAs) modify the activity of a wide range of membrane proteins and are increasingly hypothesized to modulate protein activity by indirectly altering membrane physical properties. Among the various physical properties affected by PUFAs, the membrane area expansion modulus (K), which measures membrane strain in response to applied force, is expected to be a significant controller of channel activity. Yet, the impact of PUFAs on membrane K has not been measured previously.

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Hierarchical Reactivity of Enzyme-Mediated Phosphorus Recycling from Organic Mixtures by Phytase.

J Agric Food Chem

February 2021

Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853, United States.

Biological recycling of inorganic phosphorus (P) from organic phosphorus (P) compounds by phosphatase-type enzymes, including phytases, is an important contributor to the pool of bioavailable P to plants and microorganisms. However, studies of mixed-substrate reactions with these enzymes are lacking. Here, we explore the reactivity of a phytase extract from the fungus toward a heterogeneous mixture containing, in addition to phytate, different structures of environmentally relevant P compounds such as ribonucleotides and sugar phosphates.

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Hierarchical routing in carbon metabolism favors iron-scavenging strategy in iron-deficient soil species.

Proc Natl Acad Sci U S A

December 2020

Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853;

High-affinity iron (Fe) scavenging compounds, or siderophores, are widely employed by soil bacteria to survive scarcity in bioavailable Fe. Siderophore biosynthesis relies on cellular carbon metabolism, despite reported decrease in both carbon uptake and Fe-containing metabolic proteins in Fe-deficient cells. Given this paradox, the metabolic network required to sustain the Fe-scavenging strategy is poorly understood.

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