The development of sustainable transportation and communication systems requires an increase in both energy density and capacity retention of Li-batteries. Using substrates forming a solid solution with body-centered cubic Li enhances the cycle stability of anode-less batteries. However, it remains unclear how the substrate microstructure affects the lithiation behavior.
View Article and Find Full Text PDFThe application of atom probe tomography (APT) to frozen liquids is limited by difficulties in specimen preparation. Here, we report on the use of nanoporous Cu needles as a physical framework to hold water ice for investigation using APT. Nanoporous Cu needles are prepared by electropolishing and dealloying Cu-Mn matchstick precursors.
View Article and Find Full Text PDFCryogenic atom probe tomography (cryo-APT) is being developed to enable nanoscale compositional analyses of frozen liquids. Yet, the availability of readily available substrates that allow for the fixation of liquids while providing sufficient strength to their interface is still an issue. Here, we propose the use of 1-2-µm-thick binary alloy film of gold-silver sputtered onto flat silicon, with sufficient adhesion without an additional layer.
View Article and Find Full Text PDFThe early stages of corrosion occurring at liquid-solid interfaces control the evolution of the material's degradation process, yet due to their transient state, their analysis remains a formidable challenge. Here corrosion tests are performed on a MgCa alloy, a candidate material for biodegradable implants using pure water as a model system. The corrosion reaction is suspended by plunge freezing into liquid nitrogen.
View Article and Find Full Text PDFAtom probe tomography requires needle-shaped specimens with a diameter typically below 100 nm, making them both very fragile and reactive, and defects (notches at grain boundaries or precipitates) are known to affect the yield and data quality. The use of a conformal coating directly on the sharpened specimen has been proposed to increase yield and reduce background. However, to date, these coatings have been applied ex situ and mostly are not uniform.
View Article and Find Full Text PDFReliable and consistent preparation of atom probe tomography (APT) specimens from aqueous and hydrated biological specimens remains a significant challenge. One particularly difficult process step is the use of a focused ion beam (FIB) instrument for preparing the required needle-shaped specimen, typically involving a 'lift-out' procedure of a small sample of material. Here, two alternative substrate designs are introduced that enable using FIB only for sharpening, along with example APT datasets.
View Article and Find Full Text PDFRepeatable and reliable site-specific preparation of specimens for atom probe tomography (APT) at cryogenic temperatures has proven challenging. A generalized workflow is required for cryogenic specimen preparation including lift-out via focused ion beam and in situ deposition of capping layers, to strengthen specimens that will be exposed to high electric field and stresses during field evaporation in APT and protect them from environment during transfer into the atom probe. Here, we build on existing protocols and showcase preparation and analysis of a variety of metals, oxides, and supported frozen liquids and battery materials.
View Article and Find Full Text PDFInterest in the technique of low temperature environmental nanoindentation has gained momentum in recent years. Low temperature indentation apparatuses can, for instance, be used for systematic measurements of the mechanical properties of ice in the laboratory, in order to accurately determine the inputs for the constitutive equations describing the rheologic behaviour of natural ice (i.e.
View Article and Find Full Text PDFTo advance the understanding of the degradation of the liquid electrolyte and Si electrode, and their interface, we exploit the latest developments in cryo-atom probe tomography. We evidence Si anode corrosion from the decomposition of the Li salt before charge-discharge cycles even begin. Volume shrinkage during delithiation leads to the development of nanograins from recrystallization in regions left amorphous by the lithiation.
View Article and Find Full Text PDFImaging of liquids and cryogenic biological materials by electron microscopy has been recently enabled by innovative approaches for specimen preparation and the fast development of optimized instruments for cryo-enabled electron microscopy (cryo-EM). Yet, cryo-EM typically lacks advanced analytical capabilities, in particular for light elements. With the development of protocols for frozen wet specimen preparation, atom probe tomography (APT) could advantageously complement insights gained by cryo-EM.
View Article and Find Full Text PDFBackground: Blood clot contraction, volume shrinkage of the clot, is driven by platelet contraction and accompanied by compaction of the erythrocytes and their gradual shape change from biconcave to polyhedral, with the resulting cells named polyhedrocytes.
Objectives: Here, we examined the role of erythrocyte rigidity on clot contraction and erythrocyte shape transformation.
Methods: We used an optical tracking methodology that allowed us to quantify changes in contracting clot size over time.
As a harm reduction-focused primary care clinic for people who use drugs, the Respectful and Equitable Access to Comprehensive Healthcare (REACH) Program faced multiple barriers due to the COVID-19 pandemic. We describe and evaluate how the telemedicine-driven adaptations REACH made allowed the program to engage its patients. REACH expanded its telemedicine capabilities by transitioning its in-person clinic and methods of connecting with referrals to telemedicine.
View Article and Find Full Text PDFPhysiological processes such as blood clotting and wound healing as well as pathologies such as fibroses and musculoskeletal contractures, all involve biological materials composed of a contracting cellular population within a fibrous matrix, yet how the microscale interactions among the cells and the matrix lead to the resultant emergent behavior at the macroscale tissue level remains poorly understood. Platelets, the anucleate cell fragments that do not divide nor synthesize extracellular matrix, represent an ideal model to study such systems. During blood clot contraction, microscopic platelets actively pull fibers to shrink the macroscale clot to less than 10% of its initial volume.
View Article and Find Full Text PDFSpatially resolved RNA and protein molecular analyses have revealed unexpected heterogeneity of cells. Metabolic analysis of individual cells complements these single-cell studies. Here, we present a three-dimensional spatially resolved metabolomic profiling framework (3D-SMF) to map out the spatial organization of metabolic fragments and protein signatures in immune cells of human tonsils.
View Article and Find Full Text PDFIn this article, several scholars of nationalism discuss the potential for the COVID-19 pandemic to impact the development of nationalism and world politics. To structure the discussion, the contributors respond to three questions: (1) how should we understand the relationship between nationalism and COVID-19; (2) will COVID-19 fuel ethnic and nationalist conflict; and (3) will COVID-19 reinforce or erode the nation-state in the long run? The contributors formulated their responses to these questions near to the outset of the pandemic, amid intense uncertainty. This made it acutely difficult, if not impossible, to make predictions.
View Article and Find Full Text PDFBiosens Bioelectron
October 2018
An organic aptamer functionalized electrochemical transistor has been developed to detect the presence of epinephrine molecule which acts as an excitatory neurotransmitter. The abnormalities in the level of epinephrine are the direct symptoms of some diseases such as Takotsubo cardiomyopathy, myocardial infarction, arrhythmias and other heart related diseases. The present approach is based on immobilization of aptamers on the gate electrode which selectively binds to epinephrine with high affinity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2017
Nanoscale transition-metal dichalcogenide (TMDC) materials, such as MoS, exhibit promising behavior in next-generation electronics and energy-storage devices. TMDCs have a highly anisotropic crystal structure, with edge sites and basal planes exhibiting different structural, chemical, and electronic properties. In virtually all applications, two-dimensional or bulk TMDCs must be interfaced with other materials (such as electrical contacts in a transistor).
View Article and Find Full Text PDFCase Rep Infect Dis
December 2017
is an opportunistic pathogen that rarely causes pneumonia in otherwise healthy patients. We describe a case of community-acquired pneumonia in a previously healthy individual who likely acquired the infection from a home humidifier.
View Article and Find Full Text PDFObjectives: To determine the effect of asthma on functional limitations of older adults in the United States.
Design: Analyses were conducted with data from the Asthma Beliefs and Literacy in the Elderly study, a prospective cohort study of people aged 60 and older with asthma.
Setting: Participants were recruited from urban primary care and pulmonary specialty practices in New York City and Chicago between 2010 and 2012.
Background: Apathy is a prominent feature of geriatric depression that predicts poor clinical outcomes and hinders depression treatment. Yet little is known about the neurobiology and treatment of apathy in late-life depression. This study examined apathy prevalence in a clinical sample of depressed elderly, response of apathy to selective serotonin reuptake inhibitor (SSRI) treatment, and neuroanatomical correlates that distinguished responders from non-responders and healthy controls.
View Article and Find Full Text PDFObjective: To evaluate and present 10-year outcomes of the Nova Scotia Breast Screening Program (NSBSP), a population-based screening program in the province of Nova Scotia, Canada, total population 900 000.
Setting: Organized Breast Screening Program in Nova Scotia, Canada.
Methods: Rates of participation, abnormal referrals, cancer detection rates, and benign:malignant (B:M) rates for core biopsy and surgical biopsy were calculated for asymptomatic women receiving a mammogram through the NSBSP 1991-2001.