Embedded Ribbons of Graphene Allotropes: An Extended Defect Perspective

Four fundamental dimer manipulations can be used to produce a variety of localized and extended defect structures in graphene. Two-dimensional templates result in graphene allotropes, here viewed as extended defects, which can exhibit either metallic or semiconducting electrical character. \emph{Embedded allotropic ribbons}--i.e. thin swaths of the new allotropes--can also be created within graphene. We examine these ribbons and find that they maintain the electrical character of their parent allotrope even when only a few atoms in width. Such extended defects may facilitate the construction of monolithic electronic circuitry.Comment: 24 pages, 21 figure

A theoretical review of the operation of vibratory stress relief with particular reference to the stabilization of large-scale fabrications

Vibratory stress relief (VSR) is widely used on large welded fabrications to stabilize the structures so that they do not distort during further machining or during operational duty. The level of applied stress achieved during VSR on such structures is only 5–10 per cent of the yield stress. It is, therefore, not obvious how these applied loads come to modify the level of residual stress. It is suggested here that the reason for the success of VSR applied to large fabrications lies (a) in the origin of the residual stresses and (b) in the partial relief of these residual stresses by the initiation of the transformation of retained austenite particles (in the size range from 1 to 25 µm) by the movement of dislocations into positions that are favourable for the nucleation of martensite embryos. The shear deformation associated with the transformation of retained austenite into martensite will reduce the residual stress field to the point where the stability of the structure may be assured

Thermophiles; or, the Modern Prometheus: The Importance of Extreme Microorganisms for Understanding and Applying Extracellular Electron Transfer

Approximately four billion years ago, the first microorganisms to thrive on earth were anaerobic chemoautotrophic thermophiles, a specific group of extremophiles that survive and operate at temperatures ∼50 – 125°C and do not use molecular oxygen (O2) for respiration. Instead, these microorganisms performed respiration via dissimilatory metal reduction by transferring their electrons extracellularly to insoluble electron acceptors. Genetic evidence suggests that Gram-positive thermophilic bacteria capable of extracellular electron transfer (EET) are positioned close to the root of the Bacteria kingdom on the tree of life. On the contrary, EET in Gram-negative mesophilic bacteria is a relatively new phenomenon that is evolutionarily distinct from Gram-positive bacteria. This suggests that EET evolved separately in Gram-positive thermophiles and Gram-negative mesophiles, and that EET in these bacterial types is a result of a convergent evolutionary process leading to homoplasy. Thus, the study of dissimilatory metal reducing thermophiles provides a glimpse into some of Earth’s earliest forms of respiration. This will provide new insights for understanding biogeochemistry and the development of early Earth in addition to providing unique avenues for exploration and discovery in astrobiology. Lastly, the physiological composition of Gram-positive thermophiles, coupled with the kinetic and thermodynamic consequences of surviving at elevated temperatures, makes them ideal candidates for developing new mathematical models and designing innovative next-generation biotechnologies.KEY CONCEPTSAnaerobe: organism that does not require oxygen for growth.Chemoautotroph: organism that obtains energy by oxidizing inorganic electron donors.Convergent Evolution: process in which organisms which are not closely related independently evolve similar traits due to adapting to similar ecological niches and/or environments.Dissimilatory Metal Reduction: reduction of a metal or metalloid that uses electrons from oxidized organic or inorganic electron donors.Exoelectrogen: microorganism that performs dissimilatory metal reduction via extracellular electron transfer.Extremophiles: organisms that thrive in physical or geochemical conditions that are considered detrimental to most life on Earth.Homoplasy: a character shared by a set of species that is not shared by a common ancestorNon-synonymous Substitutions (Ka): a substitution of a nucleotide that changes a codon sequence resulting in a change in the amino acid sequence of a protein.Synonymous Substitutions (Ks): a substitution of a nucleotide that may change a codon sequence, but results in no change in the amino acid sequence of a protein.Thermophiles: a specific group of extremophiles that survive and operate at temperatures ∼50–125°C

Linking structural and functional characteristics of restored oyster reefs : A Restoration Project in the Virginia Coast Reserve

Eighteen native oyster reefs (16-m2 each) were restored using six oyster densities (0, 10, 25, 50, 100 and 250 adult oysters m-2) with three replicates of each density at an intertidal site in The Nature Conservancy’s Virginia Coast Reserve. Reef construction was successful and continues to provide a range of oyster biomass densities useful for exploring relationships between oyster reef structural and functional parameters. Between April 2012 and July 2013, a science-based monitoring program explored quantitative relationships between structural and functional characteristics of these restored reefs. Structural parameters examined included oyster abundance, oyster size/biomass, surface shell volume, reef topographic complexity and sediment characteristics. Functional parameters included denitrification rates and macrofaunal abundance and biomass. Relationships between reef structural parameters and functional parameters were complex and variable. As of July 2014, these reefs continue to serves as a platform for continued studies of the relationships between reef structural and functional characteristics

Lung Cancer Screening Criteria and Cardiopulmonary Comorbidities

INTRODUCTION: Lung cancer screening criteria should select candidates with minimal cardiopulmonary comorbidities who are fit for curative lung cancer resection. METHODS: We retrospectively analyzed 728 patients with lung cancer for screening eligibility using the U.S. Preventive Services Task Force (USPSTF) 2013 criteria (n = 370). If ineligible for screening, they were further assessed for eligibility using the USPSTF 2021 (n = 121) and National Comprehensive Cancer Network group 2 (NCCN gp 2) (n = 155). Comparisons of cardiopulmonary comorbidities between patients selected by the different lung cancer screening criteria were performed. Excluding missing data, a similar comparison was done between USPSTF 2013 (n = 283) and PLCOm2012 (risk threshold ≥1.51%) (n = 118). RESULTS: Patients eligible for USPSTF 2021 and NCCN gp 2 had lower rates of airflow obstruction (forced expiratory volume in 1 s [FEV1]/forced vital capacity \u3c0.7) compared with those in USPSTF 2013 (55.4% and 56.8% versus 70.5%). Both USPSTF 2021 and NCCN gp 2 groups had less severe airflow obstruction; only 11.6% and 12.9% of patients, respectively, had percent-predicted FEV1 less than 50% versus 20.3% in the USPSTF 2013 group. Comparing USPSTF 2013 and PLCOm2012 revealed no significant differences in age or the rate of airflow obstruction (p = 0.06 and p = 0.09 respectively). Nevertheless, rates of percent-predicted FEV1 less than 50% and diffusing capacity of the lungs for carbon monoxide less than 50% were lower in the PLCOm2012 group compared with those in the USPSTF 2013 group (22.3% versus 10.2% and 32.6% versus 20.0%), respectively. CONCLUSIONS: The USPSTF 2021 qualifies an additional group of screening candidates who are healthier with better lung reserve, translating to better surgical candidacy but potentially more overdiagnosis. The PLCOm2012, with its better accuracy in selecting patients at risk of cancer, selects an older group with chronic obstructive pulmonary disease but with good lung reserve and potentially less overdiagnosis

A Placebo‐Controlled Double‐Blinded Randomized Pilot Study of Combination Phytotherapy in Biochemically Recurrent Prostate Cancer

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136500/1/pros23317_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136500/2/pros23317.pd