GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Acoustic Wave Propagation in a Borehole with a Gas Hydrate-Bearing Sediment
    MDPI AG ; 2022
    In:  Journal of Marine Science and Engineering Vol. 10, No. 2 ( 2022-02-10), p. 235-
    Details
    In: Journal of Marine Science and Engineering, MDPI AG, Vol. 10, No. 2 ( 2022-02-10), p. 235-
    Abstract: A knowledge of wave propagation in boreholes with gas hydrate-bearing sediments, a typical three-phase porous medium, is of great significance for better applications of acoustic logging information on the exploitation of gas hydrate. To study the wave propagation in such waveguides based on the Carcione–Leclaire three-phase theory, according to the equations of motion and constitutive relations, a staggered-grid finite-difference time-domain (FDTD) scheme and a real axis integration (RAI) algorithm in a two-dimensional (2D) cylindrical coordinate system are proposed. In the FDTD scheme, the partition method is used to solve the stiff problem, and the nonsplitting perfect matched layer (NPML) scheme is extended to solve the problem of the false reflection waves from the artificial boundaries of the computational region. In the RAI algorithm, combined with six boundary conditions, the displacement potentials of waves are studied to calculate the borehole acoustic wavefields. The effectiveness is verified by comparing the results of the two algorithms. On this basis, the acoustic logs within a gas hydrate-bearing sediment are investigated. In particular, the wave field in a borehole is analyzed and the amplitude of a Stoneley wave under different hydrate saturations is studied. The results indicate that the attenuation coefficient of the Stoneley wave increases with the increase of gas hydrate saturation. The acoustic responses in a borehole embedded in a horizontally stratified hydrate formation are also simulated by using the proposed FDTD scheme. The result shows that the amplitude of the Stoneley wave from the upper interface is smaller than that from the bottom interface.
    Type of Medium: Online Resource
    ISSN: 2077-1312
    URL: Article
    DOI: 10.3390/jmse10020235
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2738390-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Downregulation of MiR-199b-5p Inducing Differentiation of Bone-Marrow Mesenchymal Stem Cells (BMSCs) Toward Cardiomyocyte-Like Cells via HSF1/HSP70 Pathway
    International Scientific Information, Inc. ; 2018
    In:  Medical Science Monitor Vol. 24 ( 2018-05-01), p. 2700-2710
    Details
    In: Medical Science Monitor, International Scientific Information, Inc., Vol. 24 ( 2018-05-01), p. 2700-2710
    Type of Medium: Online Resource
    ISSN: 1643-3750
    URL: Article
    DOI: 10.12659/MSM.907441
    Language: English
    Publisher: International Scientific Information, Inc.
    Publication Date: 2018
    detail.hit.zdb_id: 2060401-4
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Simulations of collar waves for acoustic logging while drilling in the frequency and the spatial domains
    Acoustical Society of America (ASA) ; 2019
    In:  The Journal of the Acoustical Society of America Vol. 145, No. 3_Supplement ( 2019-03-01), p. 1768-1768
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 145, No. 3_Supplement ( 2019-03-01), p. 1768-1768
    Abstract: Tool waves generated by the presence of the drill collar can cover the formation signals we need. The suppression for those collar waves has been a challenge for designing acoustic logging while drilling (ALWD) tools. To study the collar wave characteristics, we evaluate the excitation intensity of the modes with varying frequencies and positions by solving the elastic wave equations. Analysis results show that the collar wave energy concentrates in the cylindrical tool model. And the radial location of its peak gradually moves from the inner surface to the outer wall with the increasing frequency. The particle vibration trajectories contributed by the collar wave are also investigated. It is revealed that the collar mode in the lower frequency range has an approximately longitudinal polarization, while it tends to the transverse-wave-like motion at high frequencies. According to these features, we propose strategies on the tool structure designs to suppress the collar waves in the lower- and the higher- frequency ranges, respectively. Numerical examples further validate that the proposed collar structures with interlayers or grooves can well attenuate the collar wave propagation.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5101478
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2019
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Non-canonical STING–PERK pathway dependent epigenetic regulation of vascular endothelial dysfunction via integrating IRF3 and NF-κB in inflammatory response
    Elsevier BV ; 2023
    In:  Acta Pharmaceutica Sinica B ( 2023-8)
    Details
    In: Acta Pharmaceutica Sinica B, Elsevier BV, ( 2023-8)
    Type of Medium: Online Resource
    ISSN: 2211-3835
    URL: Article
    DOI: 10.1016/j.apsb.2023.08.015
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2023
    detail.hit.zdb_id: 2631779-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Solution‐Doped Donor–Acceptor Copolymers Based on Diketopyrrolopyrrole and 3, 3′‐Bis (2‐(2‐(2‐Methoxyethoxy) Ethoxy) ethoxy)‐2, 2′‐Bithiophene Exhibiting Outstanding Thermoelectric Power Factors with p ‐Dopants
    Wiley ; 2024
    In:  Advanced Functional Materials Vol. 34, No. 7 ( 2024-02)
    Details
    In: Advanced Functional Materials, Wiley, Vol. 34, No. 7 ( 2024-02)
    Abstract: The design of polymeric semiconductors exhibiting high electrical conductivity (σ) and thermoelectric power factor (PF) will be vital for flexible large‐area electronics. In this work, four polymers based on diketopyrrolopyrrole (DPP), 2,3‐dihydrothieno[3,4‐b] [1,4]dioxine (EDOT), thieno[3,2‐b] thiophene (TT), and 3, 3′‐bis (2‐(2‐(2‐methoxyethoxy) ethoxy) ethoxy)‐2, 2′‐bithiophene (MEET) are investigated as side‐chains, with the MEET polymers newly synthesized for this study. These polymers are systematically doped with tetrafluorotetracyanoquinodimethane ( F 4 TCNQ), CF3SO3H, and the synthesized dopant Cp(CN) 3 ‐(COOMe) 3 , differing in geometry and electron affinity. The DPP‐EDOT‐based polymer containing MEET as side‐chains exhibits the highest conductivity (σ) ≈700 S cm−1 in this series with the acidic dopant (CF 3 SO 3 H). This polymer also shows the lowest oxidation potential by cyclic voltammetry (CV), the strongest intermolecular interactions evidenced by differential scanning calorimetry (DSC), and has the most oxygen‐based functionality for possible hydrogen bonding and ionic screening. Other polymers exhibit high σ ≈300–500 S cm−1 and power factor up to 300 µW m −1 K −2 . The mechanism of conductivity is predominantly electronic, as validated by time‐dependent conductance studies and transient thermo voltage monitoring over time, including for those doped with the acid. These materials maintain significant thermal stability and air stability over ≈6 weeks. Density functional theory calculations reveal molecular geometries and inform about frontier energy levels. Raman spectroscopy, in conjunction with scanning electron microscopy (SEM‐EDS) and x‐ray diffraction, provides insight into the solid‐state microstructure and degree of phase separation of the doped polymer films. Infrared spectroscopy enables this study to further quantify the degree of charge transfer from polymer to dopant.
    Type of Medium: Online Resource
    ISSN: 1616-301X , 1616-3028
    URL: Issue
    URL: Article
    DOI: 10.1002/adfm.v34.7
    DOI: 10.1002/adfm.202309646
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 2029061-5
    detail.hit.zdb_id: 2039420-2
    SSG: 11
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Numerical simulations of acoustic isolators in monopole acoustic logging while drilling based on phononic crystal structures
    Oxford University Press (OUP) ; 2020
    In:  Journal of Geophysics and Engineering Vol. 17, No. 2 ( 2020-04-01), p. 212-221
    Details
    In: Journal of Geophysics and Engineering, Oxford University Press (OUP), Vol. 17, No. 2 ( 2020-04-01), p. 212-221
    Abstract: In acoustic logging while drilling (ALWD), it is crucial to have an ALWD isolator to reduce collar waves and to meet the requirement of wideband acoustic measurements. In this work, we proposed a new acoustic isolator based on phononic crystal structures for reducing collar waves, and its acoustic insulation performance is numerically studied through the finite difference simulation. For the typical ALWD tool, the optimized acoustic isolator has eight-section graded grooves and each contains 11 small grooves varying from 3 to 5 mm, with an interval of 0.2 m between adjacent sections. Performances of the isolators we designed are verified by numerical results. The attenuation effects of the improved isolator and the traditional one on collar arrivals are compared. The comparison of synthetic waveforms reveals that the newly proposed design with grooves characterized by gradually varying width displays better acoustic isolation performance than the traditional isolator with uniform grooves when operated with various source central frequencies from 13 to 15 kHz. By applying the proposed isolator, the formation longitudinal wave velocities can be separated effectively from the wave group containing the collar waves in the fast formation model. These studies may be useful for the ALWD tool design and data processing.
    Type of Medium: Online Resource
    ISSN: 1742-2132 , 1742-2140
    URL: Article
    DOI: 10.1093/jge/gxz091
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 2135382-7
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Correction to: Artificial noise-assisted physical layer security in D2D-enabled cellular networks
    Springer Science and Business Media LLC ; 2017
    In:  EURASIP Journal on Wireless Communications and Networking Vol. 2017, No. 1 ( 2017-12)
    Details
    In: EURASIP Journal on Wireless Communications and Networking, Springer Science and Business Media LLC, Vol. 2017, No. 1 ( 2017-12)
    Type of Medium: Online Resource
    ISSN: 1687-1499
    URL: Article
    DOI: 10.1186/s13638-017-0984-2
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2017
    detail.hit.zdb_id: 2168613-0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Acoustic fields for monopole logging while drilling with an eccentric collar
    Society of Exploration Geophysicists ; 2021
    In:  GEOPHYSICS Vol. 86, No. 2 ( 2021-03-01), p. D43-D63
    Details
    In: GEOPHYSICS, Society of Exploration Geophysicists, Vol. 86, No. 2 ( 2021-03-01), p. D43-D63
    Abstract: The acoustic problem of an eccentric drill collar in a fluid-filled borehole has been of interest in the field of acoustic logging while drilling (ALWD) in recent years. To reduce the effects of tool eccentricity on ALWD measurements, studies on acoustic responses under such conditions are essential. This study therefore has developed an analytical method to investigate borehole wavefields with an off-center monopole ALWD tool in fast and slow formations. By evaluating the contributions of compressional and shear branch points, the effects of the tool eccentricity on individual formation primary and shear head waves are investigated. Results illustrate that tool eccentricity only affects the excitation properties and has almost no effect on the extracted velocities. The joint analysis of synthetic full waveforms and dispersion diagrams with varying eccentricity degrees indicates that multipole modes are excited when the tool is off center, and their excitation amplitudes gradually increase with the increasing eccentricity, especially in the direction of tool movement. Moreover, the dispersion analysis reveals that the two modes with intersections in the centered case are coupled when the tool becomes eccentric. In particular, the coupling performance between the Stoneley and flexural modes is the most prominent. Furthermore, the effects of tool eccentricity on the monopole acquisition method, that is, the sum of waveforms received at four orthogonal azimuths, are evaluated. Results show that the above summation method can effectively reduce the effects of slight or moderate eccentricity. However, for large or extreme eccentricity, reducing or eliminating the effects of eccentricity on the Stoneley wave is a challenge for this method. Based on the above analyses, measurements may not be reliable for formation evaluation in the case of extreme eccentricity, especially for Stoneley wave applications.
    Type of Medium: Online Resource
    ISSN: 0016-8033 , 1942-2156
    URL: Article
    DOI: 10.1190/geo2019-0744.1
    RVK:
    UA 4068.4
    Language: English
    Publisher: Society of Exploration Geophysicists
    Publication Date: 2021
    detail.hit.zdb_id: 2033021-2
    detail.hit.zdb_id: 2184-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Anti-programmed cell death-1 therapy-associated bullous disorders: a systematic review of the literature
    Ovid Technologies (Wolters Kluwer Health) ; 2018
    In:  Melanoma Research Vol. 28, No. 6 ( 2018-12), p. 491-501
    Details
    In: Melanoma Research, Ovid Technologies (Wolters Kluwer Health), Vol. 28, No. 6 ( 2018-12), p. 491-501
    Abstract: Bullous disorders are rare adverse events associated with anti-programmed cell death-1 (anti-PD1) therapy. This paper presents two new cases of bullous disorders under anti-PD1 therapy and systematically reviewed the literature to foster a better understanding of the presentation and pathogenesis of bullous disorders under anti-PD1. A systematic review of the literature was completed using MEDLINE, Embase, PubMed and LILACS databases. We identified 29 cases of bullous disorders under anti-PD1 therapy, including our two new cases. This includes 18 cases of bullous pemphigoid (BP), five cases of toxic epidermal necrolysis (TEN)/Stevens–Johnson syndrome (SJS) spectrum, one case of erythema multiforme (EM), four cases of bullous lichenoid reactions and one case of vesiculobullous eczema. In BP, blistering occurred by a median of 23 weeks after anti-PD1 therapy initiation and is often preceded by a prodrome, which lasts for a median of 9.5 weeks. Limbs and trunk were the most frequently involved body sites. Most cases (76%) achieved remission. In TEN/SJS/EM, blistering was usually preceded by a prodrome of interface dermatitis that lasted for a median of 1.5 weeks. Most cases (80%) died from either TEN/SJS or disease progression. Bullous disorders under anti-PD1 may be classified clinically as BP, SJS/TEN/EM, bullous lichenoid reactions and vesiculobullous eczema and histologically by intraepidermal splitting and subepidermal splitting. BP is usually preceded by a pruritic eruption and has a relatively good prognosis. SJS/TEN is usually preceded by a maculopapular eruption and has a very poor prognosis.
    Type of Medium: Online Resource
    ISSN: 0960-8931
    URL: Article
    DOI: 10.1097/CMR.0000000000000500
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2018
    detail.hit.zdb_id: 1095779-0
    detail.hit.zdb_id: 2030780-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Molecular Mechanism of HSF1-Upregulated ALDH2 by PKC in Ameliorating Pressure Overload-Induced Heart Failure in Mice
    Hindawi Limited ; 2020
    In:  BioMed Research International Vol. 2020 ( 2020-06-15), p. 1-14
    Details
    In: BioMed Research International, Hindawi Limited, Vol. 2020 ( 2020-06-15), p. 1-14
    Abstract: Evidences abound that HSF1 and ALDH2 are of cardioprotective effect, yet there is still no report on whether HSF1 can regulate ALDH2 to delay the occurrence of heart failure. We first established the pressure overload-induced heart failure model of mice by transverse aortic constriction (TAC) and discovered that, in the forming period of heart failure, changes of HSF1 and ALDH2 expression recorded the consistent trend. When HSF1 was upregulated/downregulated to delay/promote the occurrence of heart failure, PKC and ALDH2 also showed increased/decreased expression. And when ALDH2 was upregulated/downregulated, the role of HSF1 in delaying the occurrence of heart failure strengthened/weakened. Next, we used mechanical stretch to establish a pressure-stimulated myocardial hypertrophy model and discovered an increased expression of both HSF1 and ALDH2. When HSF1 was upregulated/downregulated to increase/decrease the expression of myocardial hypertrophy gene beta-MHC, PKC and ALDH2 recorded an increased/decreased expression. When an inhibitor was used to downregulate the expression of PKC in cardiomyocytes, we found that the role of HSF1 in upregulating ALDH2 beta-MHC weakened. These findings suggest that HSF1 can upregulate the expression of ALDH2 via PKC to promote pressure-stimulated myocardial compensatory hypertrophy, which is an important molecular pathway for HSF1 to ameliorate heart failure.
    Type of Medium: Online Resource
    ISSN: 2314-6133 , 2314-6141
    URL: Article
    DOI: 10.1155/2020/3481623
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2020
    detail.hit.zdb_id: 2698540-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...