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1.
Elife ; 122023 Dec 14.
Article in English | MEDLINE | ID: mdl-38096104

ABSTRACT

One limitation on the ability to monitor health in older adults using magnetic resonance (MR) imaging is the presence of implants, where the prevalence of implantable devices (orthopedic, cardiac, neuromodulation) increases in the population, as does the pervasiveness of conditions requiring MRI studies for diagnosis (musculoskeletal diseases, infections, or cancer). The present study describes a novel multiphysics implant modeling testbed using the following approaches with two examples: (1) an in silico human model based on the widely available Visible Human Project (VHP) cryo-section dataset; (2) a finite element method (FEM) modeling software workbench from Ansys (Electronics Desktop/Mechanical) to model MR radio frequency (RF) coils and the temperature rise modeling in heterogeneous media. The in silico VHP-Female model (250 parts with an additional 40 components specifically characterizing embedded implants and resultant surrounding tissues) corresponds to a 60-year-old female with a body mass index of 36. The testbed includes the FEM-compatible in silico human model, an implant embedding procedure, a generic parameterizable MRI RF birdcage two-port coil model, a workflow for computing heat sources on the implant surface and in adjacent tissues, and a thermal FEM solver directly linked to the MR coil simulator to determine implant heating based on an MR imaging study protocol. The primary target is MR labeling of large orthopedic implants. The testbed has very recently been approved by the US Food and Drug Administration (FDA) as a medical device development tool for 1.5 T orthopedic implant examinations.


Subject(s)
Hot Temperature , Prostheses and Implants , Female , Humans , Aged , Middle Aged , Computer Simulation , Temperature , Magnetic Resonance Imaging/methods
2.
Cureus ; 15(8): e44165, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37753051

ABSTRACT

The incidence of stroke in young individuals has been showing an increasing trend. In such cases, atypical mechanisms of stroke should be considered. Here, we report a case of a 37-year-old healthy female who presented with complaints of right-sided ataxia and clumsiness that started after an amusement park ride where she was swung rapidly. Imaging revealed an infarct in the right cerebellar hemisphere. This case report highlights certain mechanisms that can cause a stroke in this situation, with special emphasis on recognition, timely medical management, public awareness of such risk factors, and the prevention of complications.

3.
bioRxiv ; 2023 Oct 02.
Article in English | MEDLINE | ID: mdl-37649909

ABSTRACT

One limitation on the ability to monitor health in older adults using Magnetic Resonance (MR) imaging is the presence of implants, where the prevalence of implantable devices (orthopedic, cardiac, neuromodulation) increases in the population, as does the pervasiveness of conditions requiring MRI studies for diagnosis (musculoskeletal diseases, infections, or cancer). The present study describes a novel multiphysics implant modeling testbed using the following approaches with two examples: - an in-silico human model based on the widely available Visible Human Project (VHP) cryo-section dataset; - a finite element method (FEM) modeling software workbench from Ansys (Electronics Desktop/Mechanical) to model MR radio frequency (RF) coils and the temperature rise modeling in heterogeneous media. The in-silico VHP Female model (250 parts with an additional 40 components specifically characterizing embedded implants and resultant surrounding tissues) corresponds to a 60-year-old female with a body mass index (BMI) of 36. The testbed includes the FEM-compatible in-silico human model, an implant embedding procedure, a generic parameterizable MRI RF birdcage two-port coil model, a workflow for computing heat sources on the implant surface and in adjacent tissues, and a thermal FEM solver directly linked to the MR coil simulator to determine implant heating based on an MR imaging study protocol. The primary target is MR labeling of large orthopaedic implants. The testbed has very recently been approved by the US Food and Drug Administration (FDA) as a medical device development tool (MDDT) for 1.5 T orthopaedic implant examinations.

4.
Cureus ; 15(6): e41096, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37519489

ABSTRACT

This is a case report of an 83-year-old female who presented to the emergency department within eight hours of symptom onset. A CT angiogram revealed a distal basilar artery occlusion, as well as a perfusion deficit in the right superior cerebellar artery. Her symptoms fluctuated, and she was started on a heparin drip, but later in the evening her symptoms worsened. A mechanical thrombectomy was performed by interventional radiology. The following morning, most of the patient's deficits had resolved, and, when seen in the clinic several weeks later, she continued to be asymptomatic. This case report highlights the importance of timely diagnosis and intervention in the management of distal basilar artery occlusion.

5.
Environ Manage ; 70(1): 105-116, 2022 07.
Article in English | MEDLINE | ID: mdl-35524001

ABSTRACT

Impacts on households from large carnivores are frequently reported in the conservation literature, but conflicts between households and large carnivore conservation are not. Employing a human-wildlife coexistence framework that distinguishes between human-wildlife impacts on one hand, and human-conservation conflicts on the other, this paper presents data from Annapurna Conservation Area and Sagarmatha (Everest) National Park, Nepal, each with different models of conservation governance. Using systematic sampling, quantitative information from 705 households was collected via questionnaires, while 70 semi-structured interviews were conducted with key informants for cross-methods triangulation. 7.7% of households reported conflicts with snow leopard conservation in the previous 12 months, primarily due to damage to livelihoods; these were significantly higher in the Annapurna region. 373 livestock were reported lost by households to snow leopards in the previous 12 months, representing 3.4% of total livestock owned and US$ 132,450 in financial value. Livestock losses were significantly lower in the Everest area. In linear regression models, total household livestock losses to all sources best explained conflicts with snow leopard conservation and household livestock losses to snow leopards but the models for the former dependent variable had very low explanatory power. Conservation in general, and large carnivore conservation in particular, should distinguish carefully between impacts caused by coexistence with these species and conflicts with conservation actors and over the methods and interventions used to conserve carnivores, especially where these negatively impact local livelihoods. In addition, livestock husbandry standards are highlighted again as an important factor in the success of carnivore conservation programmes.


Subject(s)
Carnivora , Panthera , Animals , Animals, Wild , Conservation of Natural Resources , Humans , Livestock , Nepal , Parks, Recreational
6.
Br J Sports Med ; 56(2): 68-79, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33619127

ABSTRACT

The cessation of amateur and recreational sport has had significant implications globally, impacting economic, social and health facets of population well-being. As a result, there is pressure to resume sport at all levels. The ongoing prevalence of SARS-CoV-2 and subsequent 'second waves' require urgent best practice guidelines to be developed to return recreational (non-elite) sports as quickly as possible while prioritising the well-being of the participants and support staff.This guidance document describes the need for such advice and the process of collating available evidence. Expert opinion is integrated into this document to provide uniform and pragmatic recommendations, thereby optimising on-field and field-side safety for all involved persons, including coaches, first responders and participants.The nature of SARS-CoV-2 transmission means that the use of some procedures performed during emergency care and resuscitation could potentially be hazardous, necessitating the need for guidance on the use of personal protective equipment, the allocation of predetermined areas to manage potentially infective cases and the governance and audit of the process.


Subject(s)
COVID-19 , Pandemics , Consensus , First Aid , Humans , SARS-CoV-2
7.
Br J Sports Med ; 2020 Dec 24.
Article in English | MEDLINE | ID: mdl-33361278

ABSTRACT

The COVID-19 pandemic has necessitated many novel responses in healthcare including sport and exercise medicine. The cessation of elite sport almost globally has had significant economic implications and resulted in pressure to resume sport in very controlled conditions. This includes protecting pitch-side medical staff and players from infection. The ongoing prevalence of SARS-CoV-2 and the desire to resume professional sport required urgent best practice guidelines to be developed so that sport could be resumed as safely as possible. This set of best practice recommendations assembles early evidence for managing SARS-CoV-2 and integrates expert opinion to provide a uniform and pragmatic approach to enhance on-field and pitch-side safety for the clinician and player. The nature of SARS-CoV-2 transmission creates new hazards during resuscitation and emergency care and procedures. Recommendations for the use and type of personal protective equipment during on-field or pitch-side emergency medical care is provided based on the clinical scenario and projected risk of viral transmission.

8.
PLoS One ; 14(10): e0223565, 2019.
Article in English | MEDLINE | ID: mdl-31644548

ABSTRACT

The snow leopard Panthera uncia is a vulnerable wild felid native to mountainous regions of 12 Asian countries. It faces numerous overlapping threats, including killings by herders retaliating against livestock losses, the illegal wildlife trade, loss of prey and habitat, infrastructure, energy and mining developments, and climate change. The species ranges over large territories that often lie outside of protected areas (PA), so coexistence with human populations across its range is key to its persistence. Human attitudes to snow leopards may be an important factor to consider in reducing overlapping threats to this species. However, this nexus has not been widely studied to date. Attitudes to snow leopard conservation, including actors and interventions, may also be a significant aspect of coexistence. These have also received limited empirical attention. This study therefore explored human attitudes to snow leopards and to snow leopard conservation, the motivations for these attitudes and the individual factors that best explained them. Using systematic sampling, a quantitative questionnaire was administered to 705 households at two sites in the Nepal Himalayas: Sagarmatha National Park, with a less decentralised governance model, and Annapurna Conservation Area, with a more decentralised model. Linear regression models were the main form of analysis. Based on these, attitudes to snow leopard conservation emerged as the strongest influence on local attitudes to snow leopards, and vice versa. This was true in both PAs, despite their differing management regimes. Other important explanatory factors included numbers of livestock owned, years of education, household livelihoods and age. Furthermore, a positive intrinsic motivation was the most common reason given by respondents to explain their attitudes to both snow leopards and snow leopard conservation. These findings demonstrate that, in addition to the usual suite of factors that influence attitudes to a species, the way in which its conservation is pursued and perceived also needs consideration. How the snow leopard is conserved may strongly influence its coexistence with local communities.


Subject(s)
Attitude , Conservation of Natural Resources , Ecosystem , Felidae , Animals , Factor Analysis, Statistical , Nepal , Parks, Recreational , Predatory Behavior , Surveys and Questionnaires
9.
Angew Chem Int Ed Engl ; 57(51): 16672-16677, 2018 Dec 17.
Article in English | MEDLINE | ID: mdl-30328259

ABSTRACT

The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOx emissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra-framework positions of the small-pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition-metal/SSZ-13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtII and PdII . Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl-nitrosyl palladium complex in chabazite micropore.

10.
Chemphyschem ; 17(5): 699-709, 2016 Mar 03.
Article in English | MEDLINE | ID: mdl-26756645

ABSTRACT

We have developed a general X-ray powder diffraction (XPD) methodology for the simultaneous structural and compositional characterization of inorganic nanomaterials. The approach is validated on colloidal tungsten oxide nanocrystals (WO3-x NCs), as a model polymorphic nanoscale material system. Rod-shaped WO3-x NCs with different crystal structure and stoichiometry are comparatively investigated under an inert atmosphere and after prolonged air exposure. An initial structural model for the as-synthesized NCs is preliminarily identified by means of Rietveld analysis against several reference crystal phases, followed by atomic pair distribution function (PDF) refinement of the best-matching candidates (static analysis). Subtle stoichiometry deviations from the corresponding bulk standards are revealed. NCs exposed to air at room temperature are monitored by XPD measurements at scheduled time intervals. The static PDF analysis is complemented with an investigation into the evolution of the WO3-x NC structure, performed by applying the modulation enhanced diffraction technique to the whole time series of XPD profiles (dynamical analysis). Prolonged contact with ambient air is found to cause an appreciable increase in the static disorder of the O atoms in the WO3-x NC lattice, rather than a variation in stoichiometry. The time behavior of such structural change is identified on the basis of multivariate analysis.

11.
Zoo Biol ; 34(5): 483-91, 2015.
Article in English | MEDLINE | ID: mdl-26186494

ABSTRACT

Food procurement can play an important role in sustainable food supply chain management by zoos, linking organizational operations to the biodiversity conservation and sustainability mission of zoological collections. This study therefore examines the critical factors that shape sustainable food procurement in zoo and aquariums. Using a web-based survey data was collected from 41 members of the British and Irish Association of Zoos and Aquariums (BIAZA). This included information on the sustainable food procurement practices of these institutions for both their human and animal food supply chains, as well as profile information and data on the factors contributing to and inhibiting sustainable procurement practices. Zoological collections operated by charities, and those with a certified sustainability standard, were found to have significantly higher levels of sustainable food procurement. Zoos and aquariums whose human food operations were not contracted to an external party were also found to have significantly higher levels of sustainable food procurement in their human food supply chain. The most important drivers of sustainable food procurement were cost savings, adequate financial support and improved product quality. The highest ranking barriers were higher costs, other issues taking priority and a lack of alternative suppliers. The results suggest that a number of critical factors shape sustainable food procurement in zoological collections in the British Isles. Financial factors, such as cost savings, were important considerations. The significance of mission-related factors, such as charity status, indicated that core values held by zoos and aquariums can also influence their food procurement practices.


Subject(s)
Conservation of Natural Resources/methods , Food Supply/methods , Animals , Animals, Zoo , Aquaculture , Biodiversity , Commerce , Food Supply/ethics , Humans , Ireland , United Kingdom
12.
Geochem Geophys Geosyst ; 16(3): 870-889, 2015 03.
Article in English | MEDLINE | ID: mdl-27656114

ABSTRACT

Viscosity has been determined during isothermal crystallization of an andesite from Tungurahua volcano (Ecuador). Viscosity was continuously recorded using the concentric cylinder method and employing a Pt-sheathed alumina spindle at 1 bar and from 1400°C to subliquidus temperatures to track rheological changes during crystallization. The disposable spindle was not extracted from the sample but rather left in the sample during quenching thus preserving an undisturbed textural configuration of the crystals. The inspection of products quenched during the crystallization process reveals evidence for heterogeneous crystal nucleation at the spindle and near the crucible wall, as well as crystal alignment in the flow field. At the end of the crystallization, defined when viscosity is constant, plagioclase is homogeneously distributed throughout the crucible (with the single exception of experiment performed at the lowest temperature). In this experiments, the crystallization kinetics appear to be strongly affected by the stirring conditions of the viscosity determinations. A TTT (Time-Temperature-Transformation) diagram illustrating the crystallization "nose" for this andesite under stirring conditions and at ambient pressure has been constructed. We further note that at a given crystal content and distribution, the high aspect ratio of the acicular plagioclase yields a shear-thinning rheology at crystal contents as low as 13 vol %, and that the relative viscosity is higher than predicted from existing viscosity models. These viscosity experiments hold the potential for delivering insights into the relative influences of the cooling path, undercooling, and deformation on crystallization kinetics and resultant crystal morphologies, as well as their impact on magmatic viscosity.

13.
J Am Chem Soc ; 136(4): 1333-51, 2014 Jan 29.
Article in English | MEDLINE | ID: mdl-24437378

ABSTRACT

A combination of multinuclear ultra-wideline solid-state NMR, powder X-ray diffraction (pXRD), X-ray absorption fine structure experiments, and first principles calculations of platinum magnetic shielding tensors has been employed to reveal the previously unknown crystal structure of Magnus' pink salt (MPS), [Pt(NH3)4][PtCl4], study the isomeric Magnus' green salt (MGS), [Pt(NH3)4][PtCl4], and examine their synthetic precursors K2PtCl4 and Pt(NH3)4Cl2·H2O. A simple synthesis of MPS is detailed which produces relatively pure product in good yield. Broad (195)Pt, (14)N, and (35)Cl SSNMR powder patterns have been acquired using the WURST-CPMG and BRAIN-CP/WURST-CPMG pulse sequences. Experimentally measured and theoretically calculated platinum magnetic shielding tensors are shown to be very sensitive to the types and arrangements of coordinating ligands as well as intermolecular Pt-Pt metallophilic interactions. High-resolution (195)Pt NMR spectra of select regions of the broad (195)Pt powder patterns, in conjunction with an array of (14)N and (35)Cl spectra, reveal clear structural differences between all compounds. Rietveld refinements of synchrotron pXRD patterns, guided by first principles geometry optimization calculations, yield the space group, unit cell parameters, and atomic positions of MPS. The crystal structure has P-1 symmetry and resides in a pseudotetragonal unit cell with a distance of >5.5 Å between Pt sites in the square-planar Pt units. The long Pt-Pt distances and nonparallel orientation of Pt square planes prohibit metallophilic interactions within MPS. The combination of ultra-wideline NMR, pXRD, and computational methods offers much promise for future investigation and characterization of Pt-containing systems.

14.
ChemSusChem ; 6(12): 2231-5, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24124048

ABSTRACT

Spaced out: This paper investigates potassium-ion storage in vanadium pentoxide nanofibers (VNFs, K0.33 V2 O5 ) with a layered architecture. In situ XRD experiments reveal that the interplanar space of VNF expands/contracts upon extraction/insertion of potassium ions during the redox process.


Subject(s)
Nanofibers/chemistry , Potassium/chemistry , Vanadium Compounds/chemistry , Electric Capacitance , Electrodes , Microscopy, Electron, Transmission , Nanofibers/ultrastructure , X-Ray Diffraction
15.
Phys Chem Chem Phys ; 15(29): 12004-25, 2013 Aug 07.
Article in English | MEDLINE | ID: mdl-23660768

ABSTRACT

In this perspective article, we show how a series of in situ techniques {X-ray diffraction (XRD), pair-distribution-function analysis (PDF), X-ray absorption fine structure (XAFS), environmental transmission electron microscopy (ETEM), infrared spectroscopy (IR), ambient-pressure X-ray photoelectron spectroscopy (AP-XPS)} can be combined to perform detailed studies of the structural, electronic and chemical properties of metal oxide catalysts used for the production of hydrogen through the water-gas shift reaction (WGS, CO + H2O → H2 + CO2). Under reaction conditions most WGS catalysts undergo chemical transformations that drastically modify their composition with respect to that obtained during the synthesis process. Experiments of time-resolved in situ XRD, XAFS, and PDF indicate that the active phase of catalysts which combine Cu, Au or Pt with oxides such as ZnO, CeO2, TiO2, CeOx/TiO2 and Fe2O3 essentially involves nanoparticles of the reduced noble metals. The oxide support undergoes partial reduction and is not a simple spectator, facilitating the dissociation of water and in some cases modifying the chemical properties of the supported metal. Therefore, to optimize the performance of these catalysts one must take into consideration the properties of the metal and oxide phases. IR and AP-XPS have been used to study the reaction mechanism for the WGS on metal oxide catalysts. Data of IR spectroscopy indicate that formate species are not necessarily involved in the main reaction path for the water-gas shift on Cu-, Au- and Pt-based catalysts. Thus, a pure redox mechanism or associative mechanisms that involve either carbonate-like (CO3, HCO3) or carboxyl (HOCO) species should be considered. In the last two decades, there have been tremendous advances in our ability to study catalytic materials under reaction conditions and we are moving towards the major goal of fully understanding how the active sites for the production of hydrogen through the WGS actually work.

16.
ChemSusChem ; 6(10): 1983-92, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23650213

ABSTRACT

Hausmannite Mn3 O4 octahedral nanoparticles of 18.3 ± 7.0 nm with (101) facets have been prepared by an oxygen-mediated growth. The electrochemical properties of the Mn3 O4 particles as pseudocapacitive cathode materials were characterized both in half-cells and in button-cells. The Mn3 O4 nanoparticles exhibited a high mass-specific capacitance of 261 F g(-1), which was calculated from cyclic voltammetry analyses, and a capacitive retention of 78% after 10,000 galvanostatic charge-discharge cycles. The charge-transfer mechanisms of the Mn3 O4 nanoparticles were further studied by using synchrotron-based in situ X-ray absorption near edge spectroscopy and XRD. Both measurements showed concurrently that throughout the potential window of 0-1.2 V (vs. Ag/AgCl), a stable spinel structure of Mn3 O4 remained, and a reversible electrochemical conversion between tetrahedral [Mn(II) O4 ] and octahedral [Mn(III) O6 ] units accounted for the redox activity. Density functional theory calculations further corroborated this mechanism by confirming the enhanced redox stability afforded by the abundant and exposed (101) facets of Mn3 O4 octahedra.


Subject(s)
Manganese Compounds/chemistry , Nanoparticles/chemistry , Oxides/chemistry , Electrochemistry , Electron Transport , Models, Molecular , Molecular Conformation
17.
Bull Volcanol ; 75(11): 765, 2013.
Article in English | MEDLINE | ID: mdl-26069386

ABSTRACT

The deposits of the pyroclastic density currents from the August 2006 eruption of Tungurahua show three facies associations depending on the topographic setting: the massive, proximal cross-stratified, and distal cross-stratified facies. (1) The massive facies is confined to valleys on the slopes of the volcano. It contains clasts of >1 m diameter to fine ash material, is massive, and interpreted as deposited from dense pyroclastic flows. Its surface can exhibit lobes and levees covered with disk-shaped and vesicular large clasts. These fragile large clasts must have rafted at the surface of the flows all along the path in order to be preserved, and thus imply a sharp density boundary near the surface of these flows. (2) The proximal cross-stratified facies is exposed on valley overbanks on the upper part of the volcano and contains both massive coarse-grained layers and cross-stratified ash and lapilli bedsets. It is interpreted as deposited from (a) dense pyroclastic flows that overflowed the gentle ridges of valleys of the upper part of the volcano and (b) dilute pyroclastic density currents created from the dense flows by the entrainment of air on the steep upper flanks. (3) The distal cross-stratified facies outcrops as spatially limited, isolated, and wedge-shaped bodies of cross-stratified ash deposits located downstream of cliffs on valleys overbanks. It contains numerous aggrading dune bedforms, whose crest orientations reveal parental flow directions. A downstream decrease in the size of the dune bedforms, together with a downstream fining trend in the grain size distribution are observed on a 100-m scale. This facies is interpreted to have been deposited from dilute pyroclastic density currents with basal tractional boundary layers. We suggest that the parental flows were produced from the dense flows by entrainment of air at cliffs, and that these diluted currents might rapidly deposit through "pneumatic jumps". Three modes are present in the grain size distribution of all samples independently of the facies, which further supports the interpretation that all three facies derive from the same initial flows. This study emphasizes the influence of topography on small volume pyroclastic density currents, and the importance of flow transformation and flow-stripping processes.

18.
Br J Sports Med ; 46(16): 1097-101, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23080314

ABSTRACT

The prehospital management of serious injury is a key skill required of pitch-side medical staff. Previously, specific training in sports prehospital-immediate care was lacking or not of a comparable standard to other aspects of emergency care. Many principles have been drawn from general prehospital care or in-hospital training courses. This article discusses sports prehospital-immediate care as a niche of general prehospital care, using spinal injury management as an illustration of the major differences. It highlights the need to develop the sport-specific prehospital evidence base, rather than relying exclusively on considerations relevant to prolonged immobilisation of multiply injured casualties from motor vehicle accidents, falls from height or burns.


Subject(s)
Emergency Medical Services/standards , Emergency Medicine/education , Spinal Injuries/therapy , Sports Medicine/education , Allied Health Personnel/education , Athletic Injuries/therapy , Curriculum , Emergency Medicine/instrumentation , Emergency Medicine/standards , Equipment Design , Evidence-Based Practice , Humans , Moving and Lifting Patients/methods , Moving and Lifting Patients/standards , Oxygen/therapeutic use , Patient Care Planning/organization & administration , Patient Care Planning/standards , Sports Medicine/instrumentation , Sports Medicine/standards , Stretchers/standards , Time-to-Treatment , Triage/methods , Vacuum
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