594 research outputs found

    Superdiffusive heat conduction in semiconductor alloys -- II. Truncated L\'evy formalism for experimental analysis

    Full text link
    Nearly all experimental observations of quasi-ballistic heat flow are interpreted using Fourier theory with modified thermal conductivity. Detailed Boltzmann transport equation (BTE) analysis, however, reveals that the quasi-ballistic motion of thermal energy in semiconductor alloys is no longer Brownian but instead exhibits L\'evy dynamics with fractal dimension α<2\alpha < 2. Here, we present a framework that enables full 3D experimental analysis by retaining all essential physics of the quasi-ballistic BTE dynamics phenomenologically. A stochastic process with just two fitting parameters describes the transition from pure L\'evy superdiffusion as short length and time scales to regular Fourier diffusion. The model provides accurate fits to time domain thermoreflectance raw experimental data over the full modulation frequency range without requiring any `effective' thermal parameters and without any a priori knowledge of microscopic phonon scattering mechanisms. Identified α\alpha values for InGaAs and SiGe match ab initio BTE predictions within a few percent. Our results provide experimental evidence of fractal L\'evy heat conduction in semiconductor alloys. The formalism additionally indicates that the transient temperature inside the material differs significantly from Fourier theory and can lead to improved thermal characterization of nanoscale devices and material interfaces

    The Really Forgotten Korean War

    Get PDF
    Hawley, Samuel. 2005. The Imjin War. Japan‘s Sixteenth-Century Invasion of Korea and Attempt to Conquer China. Seoul: The Royal Asiatic Society, Korea Branch; Berkeley: The Institute of East Asian Studies, University of California, 66 4 pages, ISBN 89 954424 2

    Historical Response Factor-Based Quantification for LC-MS/MS

    Full text link

    Faciliating More Efficient Negotiations for Innovative Therapies: A Value-Based Negotiation Framework

    Get PDF
    OBJECTIVES: An increasing number of innovative therapies (e.g., gene- and cell-based treatments) have been developed in the past 20 years. Despite the significant clinical potential of these therapies, access delays may arise because of differing perspectives of manufacturers and payers regarding issues such as the value of the product, clinical and financial uncertainties, and sustainability.Managed entry agreements (MEAs) can enable access to treatments that would not be reimbursed by conventional methods because of such concerns. However, although MEA typologies exist, there is currently no structured process to come to agreements on MEAs, which can be difficult to decide upon and implement.To facilitate more structured MEA negotiations, we propose a conceptual "value-based negotiation framework" with corresponding application tools. METHODS: The framework was developed based on an iterative process of scientific literature review and expert input. RESULTS: The framework aims to (i) systematically identify and prioritize manufacturer and payer concerns about a new treatment, and (ii) select a mutually acceptable combination of MEA terms that can best address priority concerns, with the lowest possible implementation burden. CONCLUSIONS: The proposed framework will be tested in practice, and is a step toward supporting payers and manufacturers to engage in more structured, transparent negotiations to balance the needs of both sides, and enabling quicker, more transparent MEA negotiations and patient access to innovative products

    Combined cervicosternotomy and cervicotomy for true retrosternal goiters : a surgical cohort study

    Get PDF
    Objective Intrathoracic goiters are a heterogeneous group characterized by limited or extensive substernal extension. Whereas the former can be treated through cervicotomy, the latter sometimes requires a cervicosternotomy. Whether cervicosternotomy leads to more morbidity remains unclear. This study aimed to compare intra- and postoperative morbidity in patients treated by cervicotomy or cervicosternotomy for intrathoracic goiters and standard thyroidectomy. Methods In a prospectively gathered cohort undergoing thyroid surgery (2010-2019) intra- and postoperative morbidity of cervicotomy (N = 80) and cervicosternotomy (N = 15) for intrathoracic goiters was compared to each other and to a 'standard' thyroidectomy (N = 1500). Results An intrathoracic extension prior to surgery was found in 95 (6%) of all thyroidectomies. Eighty patients (84%) were operated by cervicotomy and 15 (16%) by cervicosternotomy. The risk of temporary recurrent laryngeal nerve palsy was much higher in the cervicosternotomy group (21%) compared to cervicotomy (4%) and standard thyroidectomy (3%). The risk of temporary hypocalcemia after cervicotomy (28%) was comparable to a standard thyroidectomy (32%) but higher after cervicosternotomy (20%). No cases of permanent hypocalcemia or laryngeal nerve palsy were observed in both groups with substernal extension. The need for surgical reintervention was significantly higher in the cervicotomy group (6%) compared to cervicosternotomy (0%) and standard thyroidectomy (3%). Conclusion In patients undergoing thyroid surgery for an intrathoracic goiter, cervicosternotomy was associated with more temporary laryngeal nerve palsy, but none of the interventions resulted in higher risks of permanent nerve damage, permanent hypocalcemia, or reintervention for bleeding. Reintervention was even more common after cervicotomy compared to cervicosternotomy

    Gender-Specific Modulation of the Response to Arterial Injury by Soluble Guanylate Cyclase α1

    Get PDF
    Objective: Soluble guanylate cyclase (sGC), a heterodimer composed of α and β subunits, synthesizes cGMP in response to nitric oxide (NO). NO modulates vascular tone and structure but the relative contributions of cGMP-dependent versus cGMP-independent mechanisms remain uncertain. We studied the response to vascular injury in male (M) and female (F) mice with targeted deletion of exon 6 of the sGCα1 subunit (sGCα1-/-), resulting in a non-functional heterodimer. Methods: We measured aortic cGMP levels and mRNA transcripts encoding sGC α1, α2, and β1 subunits in wild type (WT) and sGCa1-/- mice. To study the response to vascular injury, BrdU-incorporation and neointima formation (maximum intima to media (I/M) ratio) were determined 5 and 28 days after carotid artery ligation, respectively. Results: Aortic cGMP levels were 4-fold higher in F than in M mice in both genotypes, and, within each gender, 4-fold higher in WT than in sGCa1-/-. In contrast, sGCα1, sGCα2, and sGCβ1 mRNA expression did not differ between groups. 3H-thymidine incorporation in cultured sGCa1-/- smooth muscle cells (SMC) was 27%±12% lower than in WT SMC and BrdU-incorporation in carotid arteries 5 days after ligation was significantly less in sGCa1-/- M than in WT M. Neointima area and I/M 28 days after ligation were 65% and 62% lower in sGCa1-/- M than in WT M mice (p<0,05 for both) but were not different in F mice. Conclusion: Functional deletion of sGCa1 resulted in reduced cGMP levels in male sGCa1-/- mice and a gender-specific effect on the adaptive response to vascular injury

    Photochromic performance of a dithienylethene–indolinooxazolidine hybrid

    Get PDF
    The synthesis and the photochromic performance of a single-molecule system based on the covalent combination of dithienylperfluorocyclopentene and indolino[2,1-b]oxazolidine are described. The photoinduced interconversion between four states was shown to be deeply dependent on solvent and can be selectively controlled by adjusting the irradiation wavelength in chlorobenzene solutions. The color can be switched between colorless, yellow, pink and green on demand. This biphotochromic hybrid compound, despite poor fatigue resistance properties of the most conjugated colored isomer, displays large contrasts in structure, switching between zwitterionic and neutral character, independent chromophores and highly conjugated π systems
    corecore