Impact of ambient oxygen on the surface structure of α-Cr2O3(0001)

Surface x-ray diffraction has been employed to quantitatively assess the surface structure of α-Cr2O3(0001) as a function of oxygen partial pressure at room temperature. In ultrahigh vacuum, the surface is found to exhibit a partially occupied double layer of chromium atoms. At an oxygen partial pressure of 1×10−2 mbar, the surface is determined to be terminated by chromyl species (CrO), clearly demonstrating that the presence of oxygen can significantly influence the structure of α-Cr2O3(0001)

Conformational Dynamics of metallo-β-lactamase CcrA during Catalysis Investigated by Using DEER Spectroscopy

Previous crystallographic and mutagenesis studies have implicated the role of a position-conserved hairpin loop in the metallo-β-lactamases in substrate binding and catalysis. In an effort to probe the motion of that loop during catalysis, rapid-freeze-quench double electron–electron resonance (RFQ-DEER) spectroscopy was used to interrogate metallo-β-lactamase CcrA, which had a spin label at position 49 on the loop and spin labels (at positions 82, 126, or 233) 20–35 Å away from residue 49, during catalysis. At 10 ms after mixing, the DEER spectra show distance increases of 7, 10, and 13 Å between the spin label at position 49 and the spin labels at positions 82, 126, and 233, respectively. In contrast to previous hypotheses, these data suggest that the loop moves nearly 10 Å away from the metal center during catalysis and that the loop does not clamp down on the substrate during catalysis. This study demonstrates that loop motion during catalysis can be interrogated on the millisecond time scale

Sea Ice Kinematics and Thickness from RGPS: Observations and Theory

The RADARSAT Geophysical Processor System (RGPS) has produced a wealth of data on Arctic sea ice motion, deformation, and thickness with broad geographical coverage and good temporal resolution. These data provide unprecedented spatial detail of the structure and evolution of the sea ice cover. The broad purpose of this study was to take advantage of the strengths of the RGPS data set to investigate sea ice kinematics and thickness, which affect the climate through their influence on ice production, ridging, and transport (i.e. mass balance); heat flux to the atmosphere; and structure of the upper ocean mixed layer. The objectives of this study were to: (1) Explain the relationship between the discontinuous motion of the ice cover and the large-scale, smooth wind field that drives the ice; (2) Characterize the sea ice deformation in the Arctic at different temporal and spatial scales, and compare it with deformation predicted by a state-of-theart ice/ocean model; and (3) Compare RGPS-derived sea ice thickness with other data, and investigate the thinning of the Arctic sea ice cover as seen in ULS data obtained by U.S. Navy submarines. We briefly review the results of our work below, separated into the topics of sea ice deformation and sea ice thickness. This is followed by a list of publications, meetings and presentations, and other activities supported under this grant. We are attaching to this report copies of all the listed publications. Finally, we would like to point out our community service to NASA through our involvement with the ASF User Working Group and the RGPS Science Working Group, as evidenced in the list of meetings and presentations below

Scoping Review with Topic Modeling on the Diagnostic Criteria for Degenerative Cervical Myelopathy

STUDY DESIGN: This study is a scoping review. OBJECTIVE: There is a broad variability in the definition of degenerative cervical myelopathy (DCM) and no standardized set of diagnostic criteria to date. METHODS: We interrogated the Myelopathy.org database, a hand-indexed database of primary clinical studies conducted exclusively on DCM in humans between 2005-2021. The DCM inclusion criteria used in these studies were inputted into 3 topic modeling algorithms: Hierarchical Dirichlet Process (HDP), Latent Dirichlet Allocation (LDA), and BERtopic. The emerging topics were subjected to manual labeling and interpretation. RESULTS: Of 1676 reports, 120 papers (7.16%) had well-defined inclusion criteria and were subjected to topic modeling. Four topics emerged from the HDP model: disturbance from extremity weakness and motor signs; fine-motor and sensory disturbance of upper extremity; a combination of imaging and clinical findings is required for the diagnosis; and "reinforcing" (or modifying) factors that can aid in the diagnosis in borderline cases. The LDA model showed the following topics: disturbance to the patient is required for the diagnosis; reinforcing factors can aid in the diagnosis in borderline cases; clinical findings from the extremities; and a combination of imaging and clinical findings is required for the diagnosis. BERTopic identified the following topics: imaging abnormality, typical clinical features, range of objective criteria, and presence of clinical findings. CONCLUSIONS: This review provides quantifiable data that only a minority of past studies in DCM provided meaningful inclusion criteria. The items and patterns found here are very useful for the development of diagnostic criteria for DCM

Family physicians’ roles in long-term care homes and other congregate residential care settings during the COVID-19 pandemic: a qualitative study

Context: The COVID-19 pandemic disproportionally affected long-term care (LTC) homes and other community-based congregate residential care settings. Although family physicians (FPs) play important roles in the care of residents in LTC homes, provincial pandemic plans make few references to their specific roles in LTC. Objective: To examine the experiences of FPs providing care in LTC homes and other congregate care settings in Canada during the first year of the COVID-19 pandemic (2020–2021). Methods: As part of a multiple case study, we conducted semi-structured qualitative interviews with FPs across four Canadian regions. Interviews were transcribed, and a thematic analysis approach was employed. Findings: Twenty-one of the 68 FPs interviewed discussed providing care in congregate residential settings, including LTC. We identified three major themes: 1) the roles of FPs in community-based congregate residential care settings during a pandemic, 2) modification of the delivery of routine care, and 3) special workforce considerations in pandemic response for community-based congregate residential care settings. Limitations: We interviewed FPs in four Canadian jurisdictions between October 2020 and June 2021; findings may not be generalisable to later pandemic stages or to other provinces. Our recruitment strategy did not specifically target FPs who worked in different types of congregate residential care facilities; further research is needed to examine these settings in greater depth. Implications: FPs have a unique understanding of the populations they serve and are well suited to plan and implement community-adaptive procedures. Future pandemic plans should implement LTC-related FP roles during the pre-pandemic stage of a pandemic response

Arctic decadal variability : an auto-oscillatory system of heat and fresh water exchange

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 31 (2004): L03302, doi:10.1029/2003GL019023.This paper presents a mechanism of decadal variability in the Artic Ocean–GIN Sea (Greenland, Iceland and Norwegian Seas) atmosphere-ice-ocean system. We hypothesize that Arctic variability is regulated by heat and freshwater exchange between the Arctic Ocean and the GIN Sea. The interaction between basins is weak during anticyclonic circulation regimes (low AO/NAO) and strong during cyclonic circulation regimes (high AO/NAO). Regime shifts are controlled by the system itself through oceanic and atmospheric gradients (dynamic height and surface air temperature) that increase during the anticyclonic regime and decrease during the cyclonic regime. This conceptual mechanism for Arctic decadal variability has been reproduced in a model experiment. Both model results and observational data support the suggested mechanism.This research has been supported by the National Science Foundation and by the International Arctic Research Center, University of Alaska Fairbanks, under auspices of the United States National Science Foundation and from the Alaska Sea Grant through the Center for Global Change, University of Alaska Fairbanks

Adsorption structure determination of a large polyaromatic trithiolate on Cu(111): Combination of LEED-I(V) and DFT-vdW

The adsorption geometry of 1,3,5-tris(4-mercaptophenyl)benzene (TMB) on Cu(111) is determined with high precision using two independent methods, experimentally by quantitative low energy electron diffraction (LEED-I(V)) and theoretically by dispersion corrected density functional theory (DFT-vdW). Structural refinement using both methods consistently results in similar adsorption sites and geometries. Thereby a level of confidence is reached that allows deduction of subtle structural details such as molecular deformations or relaxations of copper substrate atoms

Family physicians\u27 responses to personal protective equipment shortages in four regions in Canada: a qualitative study.

BACKGROUND: Despite well-documented increased demands and shortages of personal protective equipment (PPE) during previous disease outbreaks, health systems in Canada were poorly prepared to meet the need for PPE during the COVID-19 pandemic. In the primary care sector, PPE shortages impacted the delivery of health services and contributed to increased workload, fear, and anxiety among primary care providers. This study examines family physicians\u27 (FPs) response to PPE shortages during the first year of the COVID-19 pandemic to inform future pandemic planning. METHODS: As part of a multiple case study, we conducted semi-structured qualitative interviews with FPs across four regions in Canada. During the interviews, FPs were asked to describe the pandemic-related roles they performed over different stages of the pandemic, facilitators and barriers they experienced in performing these roles, and potential roles they could have filled. Interviews were transcribed and a thematic analysis approach was employed to identify recurring themes. For the current study, we examined themes related to PPE. RESULTS: A total of 68 FPs were interviewed across the four regions. Four overarching themes were identified: 1) factors associated with good PPE access, 2) managing PPE shortages, 3) impact of PPE shortages on practice and providers, and 4) symbolism of PPE in primary care. There was a wide discrepancy in access to PPE both within and across regions, and integration with hospital or regional health authorities often resulted in better access than community-based practices. When PPE was limited, FPs described rationing and reusing these resources in an effort to conserve, which often resulted in anxiety and personal safety concerns. Many FPs expressed that PPE shortages had come to symbolize neglect and a lack of concern for the primary care sector in the pandemic response. CONCLUSIONS: During the COVID-19 pandemic response, hospital-centric plans and a lack of prioritization for primary care led to shortages of PPE for family physicians. This study highlights the need to consider primary care in PPE conservation and allocation strategies and to examine the influence of the underlying organization of primary care on PPE distribution during the pandemic

Establishing Diagnostic Criteria for Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 3].

STUDY DESIGN: Narrative review. OBJECTIVES: To discuss the importance of establishing diagnostic criteria in Degenerative Cervical Myelopathy (DCM), including factors that must be taken into account and challenges that must be overcome in this process. METHODS: Literature review summarising current evidence of establishing diagnostic criteria for DCM. RESULTS: Degenerative Cervical Myelopathy (DCM) is characterised by a degenerative process of the cervical spine resulting in chronic spinal cord dysfunction and subsequent neurological disability. Diagnostic delays lead to progressive neurological decline with associated reduction in quality of life for patients. Surgical decompression may halt neurologic worsening and, in many cases, improves function. Therefore, making a prompt diagnosis of DCM in order to facilitate early surgical intervention is a clinical priority in DCM. CONCLUSION: There are often extensive delays in the diagnosis of DCM. Presently, no single set of diagnostic criteria exists for DCM, making it challenging for clinicians to make the diagnosis. Earlier diagnosis and subsequent specialist referral could lead to improved patient outcomes using existing treatment modalities