39,745 results match your criteria Aerospace America[Journal]


Anisotropic compliance of robot legs improves recovery from swing-phase collisions.

Bioinspir Biomim 2021 Jun 15. Epub 2021 Jun 15.

Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, California, 92093, UNITED STATES.

Uneven terrain in natural environments challenges legged locomotion by inducing instability and causing limb collisions. During the swing phase, the limb releases from the ground and arcs forward to target a secure next foothold. In natural environments leg-obstacle collisions may occur during the swing phase which can result in instability, and may require contact sensing and trajectory re-planning if a collision occurs. Read More

View Article and Full-Text PDF

Risk Factors for Delirium in Older Adults in the Emergency Department: A Systematic Review and Meta-Analysis.

Ann Emerg Med 2021 Jun 11. Epub 2021 Jun 11.

Department of Emergency Medicine, Mayo Clinic, Rochester, MN; Department of Health Sciences Research, Mayo Clinic, Rochester, MN. Electronic address:

We conducted a systematic review and meta-analysis to identify risk factors for delirium in geriatric patients in the emergency department and to identify emergency department (ED)-based modifiable risk factors for developing delirium during hospitalization. We searched evidence based medicine reviews, EMBASE, MEDLINE, Scopus, and Web of Science for observational studies from the time of their inception to July 2020. We included studies that evaluated potential risk factors for either prevalent or incident delirium among older adults (age ≥ 60 years) presenting to the ED. Read More

View Article and Full-Text PDF

Tailor-made thermoplastic elastomers: customisable materials modulation of molecular weight distributions.

Chem Sci 2019 Dec 17;11(5):1361-1367. Epub 2019 Dec 17.

Department of Chemistry and Chemical Biology, Cornell University Ithaca New York 14853 USA

The ability to change polymer properties has in the past largely been a factor of modulating the molecular weight, molecular weight distribution breadth, crosslinking, or branching. The use of controlled MWD shape has recently emerged as a promising avenue towards modifying polymer properties. Taking advantage of molecular weight distribution shape, we report a simple and efficient approach for tuning material properties in polystyrene--polyisoprene--polystyrene (SIS) thermoplastic elastomers (TPEs). Read More

View Article and Full-Text PDF
December 2019

OpenIFEM: A High Performance Modular Open-Source Software of the Immersed Finite Element Method for Fluid-Structure Interactions.

Comput Model Eng Sci 2019 ;119(1):91-124

Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.

We present a high performance modularly-built open-source software - OpenIFEM. OpenIFEM is a C++ implementation of the modified immersed finite element method (mIFEM) to solve fluid-structure interaction (FSI) problems. This software is modularly built to perform multiple tasks including fluid dynamics (incompressible and slightly compressible fluid models), linear and nonlinear solid mechanics, and fully coupled fluid-structure interactions. Read More

View Article and Full-Text PDF
January 2019

A novel print-and-release method to prepare microplastics using an office-grade laserjet printer; a low-cost solution for preliminary studies.

Mar Pollut Bull 2021 Jun 11;170:112601. Epub 2021 Jun 11.

Department of Mechanical & Aerospace Engineering, College of Engineering & Computer Science, University of Central Florida, Orlando, FL, USA. Electronic address:

Microscopic plastic particles (microplastics) are widespread anthropogenic contaminants that are impacting aquatic ecosystems. Among the five most prevalent types of microplastics (polystyrene, polyamide, polyvinyl chloride, polyethylene, and polypropylene) in aquatic environments, the impact of polystyrene, polyethylene, and polypropylene has drawn more attention due to their high transportability. A lack of reliable inexpensive methods to accurately replicate the realistic microplastic samples extracted from environmental matrixes with the desired size and geometry is one of the main challenges in the design of experiments for systematic studies. Read More

View Article and Full-Text PDF

Three-dimensional imaging on a chip using optofluidics light-sheet fluorescence microscopy.

Lab Chip 2021 Jun 14. Epub 2021 Jun 14.

Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia. and Centre to Impact Antimicrobial Resistance - Sustainable Solutions, Monash University, Clayton, 3800, Victoria, Australia and The Melbourne Centre for Nanofabrication, Victorian Node - Australian National Fabrication Facility, Clayton, Victoria 3800, Australia.

Volumetric, sub-micron to micron level resolution imaging is necessary to assay phenotypes or characteristics at the sub-cellular/organelle scale. However, three-dimensional fluorescence imaging of cells is typically low throughput or compromises on the achievable resolution in space and time. Here, we capitalise on the flow control capabilities of microfluidics and combine it with microoptics to integrate light-sheet based imaging directly into a microfluidic chip. Read More

View Article and Full-Text PDF

Ferrate(VI) Oxidation Mechanism of Substituted Anilines: A Density Functional Theory Investigation.

ACS Omega 2021 Jun 25;6(22):14317-14326. Epub 2021 May 25.

College of Pharmacy, Dalian Medical University, Dalian 116044, China.

Ferrate(VI) (Fe(VI)) is a promising oxidant coagulant and disinfectant for the degradation of organic micropollutants. However, it is hard to elucidate the detailed oxidation mechanism through the current experimental approaches. Substituted anilines (SANs) are important chemical compounds that are widely used in many industries. Read More

View Article and Full-Text PDF

On the Long-Term Temporal Variations in Methane Emissions from an Unconventional Natural Gas Well Site.

ACS Omega 2021 Jun 27;6(22):14200-14207. Epub 2021 May 27.

Mechanical & Aerospace Engineering, West Virginia University, P.O. Box 6106, Morgantown, West Virginia26506, United States.

Understanding methane emissions from the natural gas supply chain continues to be of interest. Previous studies identified that measurements are skewed due to "super-emitters", and recently, researchers identified temporal variability as another contributor to discrepancies among studies. We focused on the latter by performing 17 methane audits at a single production site over 4 years, from 2016 to 2020. Read More

View Article and Full-Text PDF

Sustainable and Ecofriendly Chemical Design of High Performance Bio-Based Thermosets for Advanced Applications.

Front Chem 2021 28;9:691117. Epub 2021 May 28.

DICAM Department, University of Bologna, Bologna, Italy.

High performance thermosetting resins are targeted in many exigent applications, such as aerospace and marine fields, for the development of lightweight structural composites. Till now, these industries only rely on petroleum-based materials for their supposedly better performances. However, the latest developments in the field suggest otherwise. Read More

View Article and Full-Text PDF

Suppression of Endoplasmic Reticulum Stress by 4-PBA Protects Against Hyperoxia-Induced Acute Lung Injury Up-Regulating Claudin-4 Expression.

Front Immunol 2021 28;12:674316. Epub 2021 May 28.

Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.

Endoplasmic reticulum (ER) stress that disrupts ER function can occur in response to a wide variety of cellular stress factors leads to the accumulation of unfolded and misfolded proteins in the ER. Many studies have shown that ER stress amplified inflammatory reactions and was involved in various inflammatory diseases. However, little is known regarding the role of ER stress in hyperoxia-induced acute lung injury (HALI). Read More

View Article and Full-Text PDF

Limited Effect of 60-Days Strict Head Down Tilt Bed Rest on Vascular Aging.

Front Physiol 2021 28;12:685473. Epub 2021 May 28.

German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany.

Background: Cardiovascular risk may be increased in astronauts after long term space flights based on biomarkers indicating premature vascular aging. We tested the hypothesis that 60 days of strict 6° head down tilt bed rest (HDTBR), an established space analog, promotes vascular stiffening and that artificial gravity training ameliorates the response.

Methods: We studied 24 healthy participants (8 women, 24-55 years, BMI = 24. Read More

View Article and Full-Text PDF

Dl-3-n-Butylphthalide Alleviates Behavioral and Cognitive Symptoms Via Modulating Mitochondrial Dynamics in the A53T-α-Synuclein Mouse Model of Parkinson's Disease.

Front Neurosci 2021 28;15:647266. Epub 2021 May 28.

Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing, China.

Background: Aggregation and neurotoxicity of the presynaptic protein α-synuclein and the progressive loss of nigral dopaminergic neurons are believed to be the key hallmarks of Parkinson's disease (PD). A53T mutant α-synuclein causes early onset PD and more severe manifestations. A growing body of evidence shows that misfolding or deposition of α-synuclein is linked to the maintenance of mitochondrial dynamics, which has been proven to play an important role in the pathogenesis of PD. Read More

View Article and Full-Text PDF

Sharks surf the slope: Current updrafts reduce energy expenditure for aggregating marine predators.

J Anim Ecol 2021 Jun 13. Epub 2021 Jun 13.

MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Sète, France.

An animal's energy landscape considers the power requirements associated with residing in or moving through habitats. Within marine environments, these landscapes can be dynamic as water currents will influence animal power requirements and can change rapidly over diel and tidal cycles. In channels and along slopes with strong currents, updraft zones may reduce energy expenditure of negatively buoyant fishes that are also obligate swimmers. Read More

View Article and Full-Text PDF

Magneto-sonothrombolysis with combination of magnetic microbubbles and nanodroplets.

Ultrasonics 2021 Jun 6;116:106487. Epub 2021 Jun 6.

Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA. Electronic address:

This paper reports a novel technique using the rotational magnetic field oscillation and low-intensity sub-megahertz ultrasound stimulation of magnetic microbubbles (MMBs) to promote the nanodroplets (NDs) phase transition and improve the permeation of NDs into the blood clot fibrin network to enhance the sonothrombolysis efficiency. In this study, the influence of different treatment methods with a combination of MMBs and NDs on the thrombolysis rate of both unretracted and retracted clots were investigated, including the stable and inertial cavitation, tPA effects, MMBs/NDs concentration ratio, sonication factors (input voltage, duty cycle) and rotational magnetic field factors (flux density, frequency). We demonstrated that tPA-mediated magneto-sonothrombolysis in combining NDs with MMBs could significantly enhance in vitro lysis of both unretracted clots (85 ± 8. Read More

View Article and Full-Text PDF

Multi-frequency localized wave energy for delamination identification using laser ultrasonic guided wave.

Ultrasonics 2021 Jun 10;116:106486. Epub 2021 Jun 10.

School of Aerospace Engineering, Xiamen University, Xiamen 361005, China. Electronic address:

Delamination is the most common and dangerous failure mode for multilayered structures. Delamination defects of different shapes and sizes have different sensitivity to guided wave of different frequencies and modes. So that it is necessary to study the application of multi-frequency methods for achieving detection. Read More

View Article and Full-Text PDF

Hydroxyapatite-reinforced alginate fibers with bioinspired dually aligned architectures.

Carbohydr Polym 2021 Sep 7;267:118167. Epub 2021 May 7.

State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road No. 122, Wuhan 430070, China. Electronic address:

Biological materials have excellent mechanical properties due to their organized structures from nano- to macro-scale. Artificial manufacture of materials with anisotropic microstructures still remains challenging. We described a stress-induced method to fabricate anisotropic alginate fibers. Read More

View Article and Full-Text PDF
September 2021

Harnessing Biomaterials for Lymphatic System Modulation.

Acta Biomater 2021 Jun 9. Epub 2021 Jun 9.

Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556; Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556; Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556; Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556. Electronic address:

The lymphatic system plays an integral part in regulating immune cell trafficking and the transport of macromolecules. However, its influence on disease progression and drug uptake is understood less than that of the vascular system. To bridge this knowledge gap, biomaterials can be used to investigate the lymphatic system and to provide novel understanding into complex disease processes, including cancer metastasis and inflammation. Read More

View Article and Full-Text PDF

NiCoS Nanocrystals on Nitrogen-Doped Carbon Nanotubes as High-Performance Anode for Lithium-Ion Batteries.

Nanoscale Res Lett 2021 Jun 12;16(1):105. Epub 2021 Jun 12.

Department of Chemical and Materials Engineering, National Laboratory Astana, Nazarbayev University, Nur-Sultan, 010000, Kazakhstan.

In recent years, the development of lithium-ion batteries (LIBs) with high energy density has become one of the important research directions to fulfill the needs of electric vehicles and smart grid technologies. Nowadays, traditional LIBs have reached their limits in terms of capacity, cycle life, and stability, necessitating their further improvement and development of alternative materials with remarkably enhanced properties. A nitrogen-containing carbon nanotube (N-CNT) host for bimetallic sulfide (NiCoS) is proposed in this study as an anode with attractive electrochemical performance for LIBs. Read More

View Article and Full-Text PDF

The SARS-CoV-2 mRNA vaccine breakthrough infection phenotype includes significant symptoms, live virus shedding, and viral genetic diversity.

Clin Infect Dis 2021 Jun 12. Epub 2021 Jun 12.

Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.

Little is known about SARS-CoV-2 'vaccine-breakthrough' infections (VBI). Here we characterize 24 VBI in predominantly young healthy persons. While none required hospitalization, a proportion endorsed severe symptoms and shed live virus as high as 4. Read More

View Article and Full-Text PDF

Association of Sickle Cell Trait on Career and Operational Outcomes in the United States Air Force.

Mil Med 2021 Jun 12. Epub 2021 Jun 12.

Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.

Introduction: Sickle cell trait (SCT) is a heterozygotic state defined by having one normal hemoglobin gene and one sickle hemoglobin gene. Individuals with SCT are at increased risk for negative health outcomes during intense physical exertion, especially in hot climates and high-elevation locations, or when dehydrated. The U. Read More

View Article and Full-Text PDF

Poly(ionic liquid)s Containing Alkoxy Chains and Bis(trifluoromethanesulfonyl)imide Anions as Highly Adhesive Materials.

Adv Mater 2021 Jun 12:e2100962. Epub 2021 Jun 12.

College of Materials Science and Engineering, Hunan University, Changsha, 410004, China.

Adhesive materials have wide applications in diverse fields, but the development of a novel and multipurpose adhesive is a great challenge. This study demonstrates that conventional poly(ionic liquid)s (PILs) can be designed as highly efficient adhesives by simply introducing alkoxy moieties into the cationic backbone of PILs containing bis(trifluoromethanesulfonimide) (TFSI ) anions. The incorporated flexible alkoxy chain not only reduces the glass transition temperature of PILs but also endows these materials with strong hydrogen bonding interactions, which, together with the unique electrostatic interaction of the PILs, simultaneously contributes to a high cohesive energy and interfacial adhesive energy. Read More

View Article and Full-Text PDF

Assessing Early Cardiac Outflow Tract Adaptive Responses Through Combined Experimental-Computational Manipulations.

Ann Biomed Eng 2021 Jun 11. Epub 2021 Jun 11.

Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, 304 Weill Hall, Ithaca, NY, 14853-7202, USA.

Mechanical forces are essential for proper growth and remodeling of the primitive pharyngeal arch arteries (PAAs) into the great vessels of the heart. Despite general acknowledgement of a hemodynamic-malformation link, the direct correlation between hemodynamics and PAA morphogenesis remains poorly understood. The elusiveness is largely due to difficulty in performing isolated hemodynamic perturbations and quantifying changes in-vivo. Read More

View Article and Full-Text PDF

Dynamic self-assembly of compartmentalized DNA nanotubes.

Nat Commun 2021 06 11;12(1):3557. Epub 2021 Jun 11.

Department of Bioengineering, University of California, Los Angeles, CA, USA.

Bottom-up synthetic biology aims to engineer artificial cells capable of responsive behaviors by using a minimal set of molecular components. An important challenge toward this goal is the development of programmable biomaterials that can provide active spatial organization in cell-sized compartments. Here, we demonstrate the dynamic self-assembly of nucleic acid (NA) nanotubes inside water-in-oil droplets. Read More

View Article and Full-Text PDF

Superelastic oxide micropillars enabled by surface tension-modulated 90° domain switching with excellent fatigue resistance.

Proc Natl Acad Sci U S A 2021 Jun;118(24)

Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, 518055 Shenzhen, Guangdong, China;

Superelastic materials capable of recovering large nonlinear strains are ideal for a variety of applications in morphing structures, reconfigurable systems, and robots. However, making oxide materials superelastic has been a long-standing challenge due to their intrinsic brittleness. Here, we fabricate ferroelectric BaTiO (BTO) micropillars that not only are superelastic but also possess excellent fatigue resistance, lasting over 1 million cycles without accumulating residual strains or noticeable variation in stress-strain curves. Read More

View Article and Full-Text PDF

Evaluating the long-term effect of space radiation on the reproductive normality of mammalian sperm preserved on the International Space Station.

Sci Adv 2021 Jun 11;7(24). Epub 2021 Jun 11.

Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi 400-8510, Japan.

Space radiation may cause DNA damage to cells and concern for the inheritance of mutations in offspring after deep space exploration. However, there is no way to study the long-term effects of space radiation using biological materials. Here, we developed a method to evaluate the biological effect of space radiation and examined the reproductive potential of mouse freeze-dried spermatozoa stored on the International Space Station (ISS) for the longest period in biological research. Read More

View Article and Full-Text PDF

Floquet wave theory-based time-corrected ultrasonic total focusing method for fiber-reinforced composite laminate.

Ultrasonics 2021 May 21;116:106467. Epub 2021 May 21.

School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen 518055, PR China.

Fiber reinforced polymers (FRPs) are increasingly used in thick primary load-bearing structures. Nevertheless, manufacturing and in-service defects occur with a higher chance as the FRP thickness increases and thus the potential structure defects should be detected and evaluated. To image defects in thick FRP over 10 mm thick, this study proposes a frequency-and-structure dependent time-corrected ultrasonic total focusing method (FS-TFM) based on Floquet wave theory, which differs from conventional TFM that the wave velocity correction along different propagation direction bases on not only the structural anisotropy and inhomogeneity of FRP, but also on the probing frequency. Read More

View Article and Full-Text PDF

Association of short-term fine particulate matter exposure with pulmonary function in populations at intermediate to high-risk of cardiovascular disease: A panel study in three Chinese cities.

Ecotoxicol Environ Saf 2021 Sep 8;220:112397. Epub 2021 Jun 8.

Department of Epidemiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China; Key Laboratory of Cardiovascular Epidemiology, Chinese Academy of Medical Sciences, Beijing 100037, China. Electronic address:

Background: Decline in pulmonary function contributes to increasing cardiovascular disease (CVD) risk. Although adverse effects of short-term exposure to fine particulate matter (PM) on pulmonary function have been recognized in healthy people or patients with respiratory disease, these results were not well illustrated among people with elevated CVD risk.

Materials And Methods: A panel study was conducted in three Chinese cities with three repeated visits among populations at intermediate to high-risk of CVD, defined as treated hypertension patients or those with blood pressure ≥ 130/80 mmHg, who met any of the three conditions including abdominal obesity, dyslipidemia, and diabetes mellitus. Read More

View Article and Full-Text PDF
September 2021

Field-Dependent Dehydration and Optimal Ionic Escape Paths for CN Membranes.

J Phys Chem B 2021 Jun 11. Epub 2021 Jun 11.

Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom.

Most analytic theories describing electrostatically driven ion transport through water-filled nanopores assume that the corresponding permeation barriers are bias-independent. While this assumption may hold for sufficiently wide pores under infinitely small bias, transport through subnanometer pores under finite bias is difficult to interpret analytically. Given recent advances in subnanometer pore fabrication and the rapid progress in detailed computer simulations, it is important to identify and understand the specific field-induced phenomena arising during ion transport. Read More

View Article and Full-Text PDF

Physics of Selective Conduction and Point Mutation in Biological Ion Channels.

Phys Rev Lett 2021 May;126(21):218102

Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom.

We introduce a statistical and linear response theory of selective conduction in biological ion channels with multiple binding sites and possible point mutation. We derive an effective grand-canonical ensemble and generalized Einstein relations for the selectivity filter, assuming strongly coordinated ionic motion, and allowing for ionic Coulomb blockade. The theory agrees well with data from the KcsA K^{+} channel and a mutant. Read More

View Article and Full-Text PDF

Simultaneously enhancing redox kinetics and inhibiting the polysulfide shuttle effect using MOF-derived CoSe hollow sphere structures for advanced Li-S batteries.

Nanoscale 2021 Jun 11. Epub 2021 Jun 11.

Research Centre of Printed Flexible Electronics, School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China. and State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Shenzhen 518055, China.

Lithium-sulfur (Li-S) batteries generally suffer from a serious "shuttle effect" during the charging/discharging process, resulting in the loss of active components and sluggish redox reaction kinetics that hinder the cycle life and rate performance of the battery. To address this, CoSe/C hollow structures (CoSe/C HSs) were prepared via a simple hydrothermal strategy and used as a sulfur host for Li-S batteries. The battery with CoSe/C HSs exhibited a high initial specific discharge capacity of 1405 mA h g-1 with a coulombic efficiency of 99. Read More

View Article and Full-Text PDF