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  1. Book ; Online: Oxygen, hydrogen, and carbon isotopic compositions in deep sea cherts, porcellanites, and coexisting carbonates from DSDP Legs 2, 3, 6, 7, 11, 14, 16, 17, and 20, supplementary data to: Kolodny, Yehoshua; Epstein, Samuel (1976): Stable isotope geochemistry of deep sea cherts. Geochimica et Cosmochimica Acta, 40(10), 1195-1209

    Kolodny, Yehoshua / Epstein, Samuel

    1976  

    Abstract: Seventy four samples of DSDP recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by ... ...

    Abstract Seventy four samples of DSDP recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by mineralogical analyses and some isotopic analyses of the coexisting carbonates. d18O of chert ranges between 27 and 39%. relative to SMOW, d18O of porcellanite - between 30 and 42%. The consistent enrichment of opal-CT in porcellanites in 18O with respect to coexisting microcrystalline quartz in chert is probably a reflection of a different temperature (depth) of diagenesis of the two phases.
    d18O of deep sea cherts generally decrease with increasing age, indicating an overall cpoling of the ocean bottom during the last 150 m.y. A comparison of this trend with that recorded by benthonic foraminifera (Douglas and Savin, 1975; http://www.deepseadrilling.org/32/volume/dsdp32_15.pdf) indicates the possibility of d18O in deep sea cherts not being frozen in until several tens of millions of years after deposition. Cherts of any Age show a spread of d18O values, increasing diagenesis being reflected in a lowering of d18O. Drusy quartz has the lowest d18O values.
    On-land exposed cherts are consistently depleted in 18O in comparison to their deep sea time equivalent cherts.
    Water extracted from deep sea cherts ranges between 0.5 and 1.4 wt %. dD of this water ranges between -78 and -95%. and is not a function of d18O of the cherts (or the temperature of their formation).
    Language English
    Dates of publication 1976-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1016/0016-7037(76)90155-1
    DOI 10.1594/PANGAEA.706917
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  2. Article ; Online: Axial Optical Traps: A New Direction for Optical Tweezers.

    Yehoshua, Samuel / Pollari, Russell / Milstein, Joshua N

    Biophysical journal

    2015  Volume 108, Issue 12, Page(s) 2759–2766

    Abstract: Optical tweezers have revolutionized our understanding of the microscopic world. Axial optical tweezers, which apply force to a surface-tethered molecule by directly moving either the trap or the stage along the laser beam axis, offer several potential ... ...

    Abstract Optical tweezers have revolutionized our understanding of the microscopic world. Axial optical tweezers, which apply force to a surface-tethered molecule by directly moving either the trap or the stage along the laser beam axis, offer several potential benefits when studying a range of novel biophysical phenomena. This geometry, although it is conceptually straightforward, suffers from aberrations that result in variation of the trap stiffness when the distance between the microscope coverslip and the trap focus is being changed. Many standard techniques, such as back-focal-plane interferometry, are difficult to employ in this geometry due to back-scattered light between the bead and the coverslip, whereas the noise inherent in a surface-tethered assay can severely limit the resolution of an experiment. Because of these complications, precision force spectroscopy measurements have adapted alternative geometries such as the highly successful dumbbell traps. In recent years, however, most of the difficulties inherent in constructing a precision axial optical tweezers have been solved. This review article aims to inform the reader about recent progress in axial optical trapping, as well as the potential for these devices to perform innovative biophysical measurements.
    MeSH term(s) Optical Tweezers ; Spectrum Analysis/instrumentation ; Spectrum Analysis/methods
    Language English
    Publishing date 2015-06-16
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1016/j.bpj.2015.05.014
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: A biomechanical mechanism for initiating DNA packaging.

    Wang, Haowei / Yehoshua, Samuel / Ali, Sabrina S / Navarre, William Wiley / Milstein, Joshua N

    Nucleic acids research

    2014  Volume 42, Issue 19, Page(s) 11921–11927

    Abstract: The bacterial chromosome is under varying levels of mechanical stress due to a high degree of crowding and dynamic protein-DNA interactions experienced within the nucleoid. DNA tension is difficult to measure in cells and its functional significance ... ...

    Abstract The bacterial chromosome is under varying levels of mechanical stress due to a high degree of crowding and dynamic protein-DNA interactions experienced within the nucleoid. DNA tension is difficult to measure in cells and its functional significance remains unclear although in vitro experiments have implicated a range of biomechanical phenomena. Using single-molecule tools, we have uncovered a novel protein-DNA interaction that responds to fluctuations in mechanical tension by condensing DNA. We combined tethered particle motion (TPM) and optical tweezers experiments to probe the effects of tension on DNA in the presence of the Hha/H-NS complex. The nucleoid structuring protein H-NS is a key regulator of DNA condensation and gene expression in enterobacteria and its activity in vivo is affected by the accessory factor Hha. We find that tension, induced by optical tweezers, causes the rapid compaction of DNA in the presence of the Hha/H-NS complex, but not in the presence of H-NS alone. Our results imply that H-NS requires Hha to condense bacterial DNA and that this condensation could be triggered by the level of mechanical tension experienced along different regions of the chromosome.
    MeSH term(s) Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Biomechanical Phenomena ; DNA Packaging ; DNA, Bacterial/metabolism ; DNA-Binding Proteins/genetics ; DNA-Binding Proteins/metabolism ; Mutation
    Chemical Substances Bacterial Proteins ; DNA, Bacterial ; DNA-Binding Proteins ; H-NS protein, bacteria
    Language English
    Publishing date 2014-10-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 186809-3
    ISSN 1362-4962 ; 1362-4954 ; 0301-5610 ; 0305-1048
    ISSN (online) 1362-4962 ; 1362-4954
    ISSN 0301-5610 ; 0305-1048
    DOI 10.1093/nar/gku896
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Prevalence and outcomes of patients receiving implantable cardioverter-defibrillators for primary prevention not based on guidelines.

    Levine, Yehoshua C / Tuttle, Mark K / Rosenberg, Michael A / Goldberg, Randal / Matos, Jason / Samuel, Michelle / Kramer, Daniel B / Buxton, Alfred E

    The American journal of cardiology

    2015  Volume 115, Issue 11, Page(s) 1539–1544

    Abstract: Implantable cardioverter-defibrillator (ICD) implantation outside practice guidelines remains contentious, particularly during the mandated waiting periods in patients with recent cardiac events. We assessed the prevalence and outcomes of non-guideline- ... ...

    Abstract Implantable cardioverter-defibrillator (ICD) implantation outside practice guidelines remains contentious, particularly during the mandated waiting periods in patients with recent cardiac events. We assessed the prevalence and outcomes of non-guideline-based (NGB) ICD implantations in a tertiary academic medical center, with a specific focus on adjudication of arrhythmia events. All patients who underwent initial primary prevention ICD implantation at our institution from 2004 to 2012 were categorized as having received guideline-based (GB) or NGB implants and were retrospectively assessed for first episode of appropriate ICD therapy and total mortality. Of 807 patients, 137 (17.0%) received NGB implants. During a median follow-up of 2.9 years, patients with NGB implants had similar times to first appropriate ICD therapy (median time to event 1.94 vs 2.17 years in patients with GB implants, p = 0.20). After multivariable analysis, patients with NGB implants remained at higher risk for death (hazard ratio 1.54, 95% confidence interval 1.1 to 2.2, p = 0.03) but not appropriate ICD therapy (hazard ratio 0.83, 95% confidence interval 0.5 to 1.3, p = 0.51). Furthermore, only 1 of 125 patients who underwent implant within the 40-day waiting period after myocardial infarction or 3-month waiting period after revascularization or cardiomyopathy diagnosis received an appropriate therapy within this period. In conclusion, few patients received NGB ICD implants in our academic medical center. Although these patients have similar long-term risk of receiving appropriate ICD therapy compared with patients with GB implants, this risk is very low during the waiting periods mandated by clinical practice guidelines. These results suggest that there is little need to rush into implanting ICDs during these waiting periods.
    MeSH term(s) Aged ; Death, Sudden, Cardiac/prevention & control ; Defibrillators, Implantable/statistics & numerical data ; Female ; Humans ; Male ; Practice Guidelines as Topic ; Primary Prevention ; Prosthesis Implantation/standards ; Retrospective Studies ; Treatment Outcome
    Language English
    Publishing date 2015-06-01
    Publishing country United States
    Document type Comparative Study ; Evaluation Studies ; Journal Article
    ZDB-ID 80014-4
    ISSN 1879-1913 ; 0002-9149
    ISSN (online) 1879-1913
    ISSN 0002-9149
    DOI 10.1016/j.amjcard.2015.02.056
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: B-type natriuretic peptide is a major predictor of ventricular tachyarrhythmias.

    Levine, Yehoshua C / Rosenberg, Michael A / Mittleman, Murray / Samuel, Michelle / Methachittiphan, Nilubon / Link, Mark / Josephson, Mark E / Buxton, Alfred E

    Heart rhythm

    2014  Volume 11, Issue 7, Page(s) 1109–1116

    Abstract: Background: The cost-effective use of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death requires identification of patients at risk for ventricular tachyarrhythmias, not just for total mortality.: Objective: To ...

    Abstract Background: The cost-effective use of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death requires identification of patients at risk for ventricular tachyarrhythmias, not just for total mortality.
    Objective: To determine whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) or B-type natriuretic peptide (BNP) are independent predictors of ventricular arrhythmias in patients receiving primary prevention ICDs.
    Methods: One hundred sixty-one patients with NT-proBNP levels and 403 patients with BNP levels at the time of ICD implantation were retrospectively assessed for the occurrence of first appropriate ICD therapy and mortality.
    Results: In multivariable Cox proportional hazards regression analysis, NT-proBNP or BNP levels in the upper 50th percentile were the strongest predictor of ICD therapy after adjustment for sex, age, left ventricular ejection fraction, New York Heart Association class, history of coronary artery disease, blood urea nitrogen, creatinine clearance, and history of atrial fibrillation (hazard ratio [HR] 5.75, P < .001 for NT-proBNP; HR 3.40, P = .01 for BNP). Patients were divided into quartiles on the basis of NT-proBNP or BNP levels. The adjusted HR for ICD therapy in the highest and second highest quartiles of NT-proBNP levels (HR 12.9, P < .001, and HR 4.6, P = .03, respectively) were higher than the adjusted HR for total mortality in these 2 quartiles (HR 3.4, P = .021 and HR 2.3, P = .13, respectively). Similarly, the adjusted HR for ICD therapy in the highest and second highest quartiles of BNP levels (HR 4.74, P = .01 and HR 2.17, P = .04, respectively) were higher than the adjusted HR for total mortality in these 2 quartiles (HR 3.05, P = .01 and HR 1.07, P = .3, respectively).
    Conclusion: In this study, elevated baseline NT-proBNP and BNP levels are independently associated with the risk for ventricular tachyarrhythmias, which significantly exceeds the risk for total mortality, in multivariable analysis.
    MeSH term(s) Aged ; Biomarkers/blood ; Death, Sudden, Cardiac/prevention & control ; Defibrillators, Implantable ; Female ; Humans ; Male ; Middle Aged ; Natriuretic Peptide, Brain/blood ; Peptide Fragments/blood ; Proportional Hazards Models ; Retrospective Studies ; Risk Factors ; Survival Analysis ; Tachycardia/blood ; Tachycardia/therapy
    Chemical Substances Biomarkers ; Peptide Fragments ; pro-brain natriuretic peptide (1-76) ; Natriuretic Peptide, Brain (114471-18-0)
    Language English
    Publishing date 2014-07
    Publishing country United States
    Document type Journal Article ; Multicenter Study
    ZDB-ID 2229357-7
    ISSN 1556-3871 ; 1547-5271
    ISSN (online) 1556-3871
    ISSN 1547-5271
    DOI 10.1016/j.hrthm.2014.04.024
    Database MEDical Literature Analysis and Retrieval System OnLINE

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