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Low Temperature Dynamic Polaron Liquid in a Manganite Exhibiting Colossal Magnetoresistance. PHYSICAL REVIEW LETTERS 2024; 132:186502. [PMID: 38759205 DOI: 10.1103/physrevlett.132.186502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 03/04/2024] [Accepted: 04/01/2024] [Indexed: 05/19/2024]
Abstract
Polarons-fermionic charge carriers bearing a strong companion lattice deformation-exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in insulators, how they evolve in transitions to metallic and superconducting states in quantum materials remains an open question. Here, we use resonant inelastic x-ray scattering to track the electron-lattice coupling in the colossal magneto-resistive bi-layer manganite La_{1.2}Sr_{1.8}Mn_{2}O_{7} across its metal-to-insulator transition. The response in the insulating high-temperature state features harmonic emissions of a dispersionless oxygen phonon at small energy transfer. Upon cooling into the metallic state, we observe a drastic redistribution of spectral weight from the region of these harmonic emissions to a broad high energy continuum. In concert with theoretical calculations, we show that this evolution implies a shift in electron-lattice coupling from static to dynamic lattice distortions that leads to a distinct polaronic ground state in the low temperature metallic phase-a dynamic polaron liquid.
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Magnetic excitations in infinite-layer nickelates. Science 2021; 373:213-216. [DOI: 10.1126/science.abd7726] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/08/2020] [Accepted: 05/21/2021] [Indexed: 11/03/2022]
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Publisher Correction: Electronic structure of the parent compound of superconducting infinite-layer nickelates. NATURE MATERIALS 2020; 19:1036. [PMID: 32661388 DOI: 10.1038/s41563-020-0761-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Electronic structure of the parent compound of superconducting infinite-layer nickelates. NATURE MATERIALS 2020; 19:381-385. [PMID: 31959951 DOI: 10.1038/s41563-019-0585-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/11/2019] [Indexed: 05/21/2023]
Abstract
The search continues for nickel oxide-based materials with electronic properties similar to cuprate high-temperature superconductors1-10. The recent discovery of superconductivity in the doped infinite-layer nickelate NdNiO2 (refs. 11,12) has strengthened these efforts. Here, we use X-ray spectroscopy and density functional theory to show that the electronic structure of LaNiO2 and NdNiO2, while similar to the cuprates, includes significant distinctions. Unlike cuprates, the rare-earth spacer layer in the infinite-layer nickelate supports a weakly interacting three-dimensional 5d metallic state, which hybridizes with a quasi-two-dimensional, strongly correlated state with [Formula: see text] symmetry in the NiO2 layers. Thus, the infinite-layer nickelate can be regarded as a sibling of the rare-earth intermetallics13-15, which are well known for heavy fermion behaviour, where the NiO2 correlated layers play an analogous role to the 4f states in rare-earth heavy fermion compounds. This Kondo- or Anderson-lattice-like 'oxide-intermetallic' replaces the Mott insulator as the reference state from which superconductivity emerges upon doping.
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Pressure Effects on the 4f Electronic Structure of Light Lanthanides. PHYSICAL REVIEW LETTERS 2019; 122:066401. [PMID: 30822065 DOI: 10.1103/physrevlett.122.066401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Indexed: 06/09/2023]
Abstract
Using the satellite structure of the Lγ_{1} line in nonresonant x-ray emission spectra, we probe the high-pressure evolution of the bare 4f signature of the early light lanthanides at ambient temperature. For Ce and Pr the satellite peak experiences a sudden reduction concurrent with their respective volume collapse (VC) transitions. These new experimental results are supported by calculations using state-of-the-art extended atomic structure codes for Ce and Pr, and also for Nd, which does not exhibit a VC. Our work suggests that changes to the 4f occupation are more consistently associated with evolution of the satellite than is the reduction of the 4f moment. Indeed, we show that in the case of Ce, mixing of a higher atomic angular momentum state, driven by the increased hybridization, acts to obscure the expected satellite reduction. These measurements emphasize the importance of a unified study of a full set of microscopic observables to obtain the most discerning test of the underlying, fundamental f-electron phenomena at high pressures.
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Three-dimensional collective charge excitations in electron-doped copper oxide superconductors. Nature 2018; 563:374-378. [PMID: 30429543 DOI: 10.1038/s41586-018-0648-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/22/2018] [Indexed: 11/09/2022]
Abstract
High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12.
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Rapid change of superconductivity and electron-phonon coupling through critical doping in Bi-2212. Science 2018; 362:62-65. [DOI: 10.1126/science.aar3394] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 07/30/2018] [Indexed: 11/02/2022]
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International Normalized Ratio (INR) – Proficiency Tests by ÖQUASTA for the Prothrombin Time. Hamostaseologie 2018. [DOI: 10.1055/s-0038-1655285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
SummaryAlthough the INR (International Normalized Ratio)/ISI (International Sensitivity Index) scheme was introduced by the WHO (13) in 1983 to standardize the PT (prothrombin time) expression, the use of the non-comparable percent of a normal fresh plasma, seconds or PT-ratio (patient plasma/normal plasma) is still common in the coagulation laboratories. The availability of the INR/ISI scheme to monitor quality control of the laboratories in a reagent and method independent manner was examined by the comparison of 13 PT proficiency tests carried out by the ÖQUASTA (Austrian Society of Quality Assurance and Standardization of Diagnostic Medical Investigations).In each proficiency test approximately 250 laboratories had to determine the PT of two to three lyophilized plasma samples with their routinely used reagents and methods. The INR mean values of the AK-plasmas (plasmapools from patients under anticoagulant therapy) were between 2 and 5. The determined data and the calculated INR-values were returned to the ÖQUASTA.According to the INR/ISI scheme, all data should be considered as belonging to the same collective (TC = total collective). To prove this demand, additionally each reagent and method was evaluated separately (SC = single collective). It could be shown that the INR mean values obtained from all data and using TC or SC evaluation are nearly equivalent indicating that the TC evaluation is suitable for use in proficiency tests.The aim of a better comparability of the PT values can not only be reached by the laboratories through the use of the INR/ISI scheme. Additionally, the manufacturer are asked to standardize their ISI and 100% value determination. The manufacturer took this into account by establishing a candidate reference plasma (5).It could be shown that the introduction of the INR was not only an important step forward in terms of standardization and comparability of different thromboplastin reagents, but also in the quality control of the laboratories checked in proficiency tests in Austria.
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Light-Enhanced Spin Fluctuations and d-Wave Superconductivity at a Phase Boundary. PHYSICAL REVIEW LETTERS 2018; 120:246402. [PMID: 29957014 DOI: 10.1103/physrevlett.120.246402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Indexed: 06/08/2023]
Abstract
Time-domain techniques have shown the potential of photomanipulating existing orders and inducing new states of matter in strongly correlated materials. Using time-resolved exact diagonalization, we perform numerical studies of pump dynamics in a Mott-Peierls system with competing charge and spin density waves. A light-enhanced d-wave superconductivity is observed when the system resides near a quantum phase boundary. By examining the evolution of spin, charge, and superconducting susceptibilities, we show that a subdominant state in equilibrium can be stabilized by photomanipulating the charge order to allow superconductivity to appear and dominate. This work provides an interpretation of light-induced superconductivity from the perspective of order competition and offers a promising approach for designing novel emergent states out of equilibrium.
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Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser. Science 2018; 357:71-75. [PMID: 28684521 DOI: 10.1126/science.aak9946] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 05/03/2017] [Indexed: 11/02/2022]
Abstract
The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a "coherent lock-in" measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.
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Population Modeling Integrating Pharmacokinetics, Pharmacodynamics, Pharmacogenetics, and Clinical Outcome in Patients With Sunitinib-Treated Cancer. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2017; 6:604-613. [PMID: 28571114 PMCID: PMC5613186 DOI: 10.1002/psp4.12210] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/01/2017] [Accepted: 05/13/2017] [Indexed: 12/15/2022]
Abstract
The tyrosine kinase inhibitor sunitinib is used as first‐line therapy in patients with metastasized renal cell carcinoma (mRCC), given in fixed‐dose regimens despite its high variability in pharmacokinetics (PKs). Interindividual variability of drug exposure may be responsible for differences in response. Therefore, dosing strategies based on pharmacokinetic/pharmacodynamic (PK/PD) models may be useful to optimize treatment. Plasma concentrations of sunitinib, its active metabolite SU12662, and the soluble vascular endothelial growth factor receptors sVEGFR‐2 and sVEGFR‐3, were measured in 26 patients with mRCC within the EuroTARGET project and 21 patients with metastasized colorectal cancer (mCRC) from the C‐II‐005 study. Based on these observations, PK/PD models with potential influence of genetic predictors were developed and linked to time‐to‐event (TTE) models. Baseline sVEGFR‐2 levels were associated with clinical outcome in patients with mRCC, whereas active drug PKs seemed to be more predictive in patients with mCRC. The models provide the basis of PK/PD‐guided strategies for the individualization of anti‐angiogenic therapies.
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Prospective, multi-center study of 5-fluorouracil (5-FU) therapeutic drug management (TDM) in metastatic colorectal cancer (mCRC) patients treated in routine clinical practice. J Clin Oncol 2017. [DOI: 10.1200/jco.2017.35.4_suppl.650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
650 Background: Studies have demonstrated that body surface area (BSA)-based dosing of chemotherapy drugs leads to significant individual exposure variability with a substantial risk of under- or overdosing. This study was initiated to validate use of TDM to personalize 5-FU dosing in mCRC patients treated in routine clinical practice. Methods: 75 mCRC patients from 8 German medical centers received up to 6 administrations of infusional 5-FU according to either the AIO (n = 16), FOLFOX6 (n = 26) or FUFOX (n = 33) regimen. Initial infusional 5-FU dosing for all patients was based on BSA. Individual 5-FU exposure (AUC) was measured by an immunoassay using a blood sample drawn during each infusion. To achieve target AUC of 20 to 30 mg•h/L, subsequent infusional 5-FU doses were adjusted according to the previous cycle 5-FU AUC. Tumor markers CEA and CA19-9 were also measured before, during and after treatment. Primary objective was to confirm TDM of infusional 5-FU resulted in an increased proportion of patients in the target AUC range at the 4th versus the 1st administration. Secondary objective was to determine whether 5-FU TDM reduced treatment-related toxicities compared to historical data. Results: Average 5-FU AUC at 1st administration was 18 + 6 mg•h/L, with 64%, 33% and 3% of the patients below, within or above target AUC range, respectively. By the 4th administration average 5-FU AUC was 25 + 7 mg•h/L (p < 0.001), with 54% patients within the target 5-FU AUC range (p = 0.0294). Compared to baseline levels, CEA and CA19-9 remained stable or decreased at the end of treatment in 82% and 84% of the patients, respectively. 5-FU-related grade 3-4 diarrhea (4.6%), nausea (3.4%), fatigue (0.0%) and mucositis (0.2%) were reduced compared to historical data inspite of 55% of patients having their doses increased. Conclusions: Personalization of 5-FU dosing via TDM in routine clinical practice resulted in significantly improved 5-FU exposure and suggested lower 5-FU-related toxicities. Clinical trial information: 2011-003553-26.
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Distinct Electronic Structure for the Extreme Magnetoresistance in YSb. PHYSICAL REVIEW LETTERS 2016; 117:267201. [PMID: 28059532 DOI: 10.1103/physrevlett.117.267201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 06/06/2023]
Abstract
An extreme magnetoresistance (XMR) has recently been observed in several nonmagnetic semimetals. Increasing experimental and theoretical evidence indicates that the XMR can be driven by either topological protection or electron-hole compensation. Here, by investigating the electronic structure of a XMR material, YSb, we present spectroscopic evidence for a special case which lacks topological protection and perfect electron-hole compensation. Further investigations reveal that a cooperative action of a substantial difference between electron and hole mobility and a moderate carrier compensation might contribute to the XMR in YSb.
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Origin of the low critical observing temperature of the quantum anomalous Hall effect in V-doped (Bi, Sb)2Te3 film. Sci Rep 2016; 6:32732. [PMID: 27599406 PMCID: PMC5013448 DOI: 10.1038/srep32732] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/08/2016] [Indexed: 11/09/2022] Open
Abstract
The experimental realization of the quantum anomalous Hall (QAH) effect in magnetically-doped (Bi, Sb)2Te3 films stands out as a landmark of modern condensed matter physics. However, ultra-low temperatures down to few tens of mK are needed to reach the quantization of Hall resistance, which is two orders of magnitude lower than the ferromagnetic phase transition temperature of the films. Here, we systematically study the band structure of V-doped (Bi, Sb)2Te3 thin films by angle-resolved photoemission spectroscopy (ARPES) and show unambiguously that the bulk valence band (BVB) maximum lies higher in energy than the surface state Dirac point. Our results demonstrate clear evidence that localization of BVB carriers plays an active role and can account for the temperature discrepancy.
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Open-label, randomized study of individualized, pharmacokinetically (PK)-guided dosing of paclitaxel combined with carboplatin or cisplatin in patients with advanced non-small-cell lung cancer (NSCLC). Ann Oncol 2016; 27:1895-902. [PMID: 27502710 DOI: 10.1093/annonc/mdw290] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/14/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Variable chemotherapy exposure may cause toxicity or lack of efficacy. This study was initiated to validate pharmacokinetically (PK)-guided paclitaxel dosing in patients with advanced non-small-cell lung cancer (NSCLC) to avoid supra- or subtherapeutic exposure. PATIENTS AND METHODS Patients with newly diagnosed, advanced NSCLC were randomly assigned to receive up to 6 cycles of 3-weekly carboplatin AUC 6 or cisplatin 80 mg/m(2) either with standard paclitaxel at 200 mg/m(2) (arm A) or PK-guided dosing of paclitaxel (arm B). In arm B, initial paclitaxel dose was adjusted to body surface area, age, sex, and subsequent doses were guided by neutropenia and previous-cycle paclitaxel exposure [time above a plasma concentration of 0.05 µM (Tc>0.05)] determined from a single blood sample on day 2. The primary end point was grade 4 neutropenia; secondary end points included neuropathy, radiological response, progression-free survival (PFS) and overall survival (OS). RESULTS Among 365 patients randomly assigned, grade 4 neutropenia was similar in both arms (19% versus 16%; P = 0.10). Neuropathy grade ≥2 (38% versus 23%, P < 0.001) and grade ≥3 (9% versus 2%, P < 0.001) was significantly lower in arm B, independent of the platinum drug used. The median final paclitaxel dose was significantly lower in arm B (199 versus 150 mg/m(2), P < 0.001). Response rate was similar in arms A and B (31% versus 27%, P = 0.405), as was adjusted median PFS [5.5 versus 4.9 months, hazard ratio (HR) 1.16, 95% confidence interval (CI) 0.91-1.49, P = 0.228] and OS (10.1 versus 9.5 months, HR 1.05, 95% CI 0.81-1.37, P = 0.682). CONCLUSION PK-guided dosing of paclitaxel does not improve severe neutropenia, but reduces paclitaxel-associated neuropathy and thereby improves the benefit-risk profile in patients with advanced NSCLC. CLINICAL TRIAL INFORMATION NCT01326767 (https://clinicaltrials.gov/ct2/show/NCT01326767).
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Tailoring the nature and strength of electron-phonon interactions in the SrTiO3(001) 2D electron liquid. NATURE MATERIALS 2016; 15:835-839. [PMID: 27064529 DOI: 10.1038/nmat4623] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Surfaces and interfaces offer new possibilities for tailoring the many-body interactions that dominate the electrical and thermal properties of transition metal oxides. Here, we use the prototypical two-dimensional electron liquid (2DEL) at the SrTiO3(001) surface to reveal a remarkably complex evolution of electron-phonon coupling with the tunable carrier density of this system. At low density, where superconductivity is found in the analogous 2DEL at the LaAlO3/SrTiO3 interface, our angle-resolved photoemission data show replica bands separated by 100 meV from the main bands. This is a hallmark of a coherent polaronic liquid and implies long-range coupling to a single longitudinal optical phonon branch. In the overdoped regime the preferential coupling to this branch decreases and the 2DEL undergoes a crossover to a more conventional metallic state with weaker short-range electron-phonon interaction. These results place constraints on the theoretical description of superconductivity and allow a unified understanding of the transport properties in SrTiO3-based 2DELs.
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Using Nonequilibrium Dynamics to Probe Competing Orders in a Mott-Peierls System. PHYSICAL REVIEW LETTERS 2016; 116:086401. [PMID: 26967429 DOI: 10.1103/physrevlett.116.086401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Indexed: 06/05/2023]
Abstract
Competition between ordered phases, and their associated phase transitions, are significant in the study of strongly correlated systems. Here, we examine one aspect, the nonequilibrium dynamics of a photoexcited Mott-Peierls system, using an effective Peierls-Hubbard model and exact diagonalization. Near a transition where spin and charge become strongly intertwined, we observe antiphase dynamics and a coupling-strength-dependent suppression or enhancement in the static structure factors. The renormalized bosonic excitations coupled to a particular photoexcited electron can be extracted, which provides an approach for characterizing the underlying bosonic modes. The results from this analysis for different electronic momenta show an uneven softening due to a stronger coupling near k_{F}. This behavior reflects the strong link between the fermionic momenta, the coupling vertices, and ultimately, the bosonic susceptibilities when multiple phases compete for the ground state of the system.
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Open-label, randomized study of individualized, pharmacokinetically (PK)-guided dosing of paclitaxel combined with carboplatin in advanced Non-Small Cell Lung Cancer (NSCLC) patient. Pneumologie 2016. [DOI: 10.1055/s-0036-1572244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates. Sci Rep 2016; 6:19657. [PMID: 26794437 PMCID: PMC4726252 DOI: 10.1038/srep19657] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022] Open
Abstract
Measurements of spin excitations are essential for an understanding of spin-mediated pairing for superconductivity; and resonant inelastic X-ray scattering (RIXS) provides a considerable opportunity to probe high-energy spin excitations. However, whether RIXS correctly measures the collective spin excitations of doped superconducting cuprates remains under debate. Here we demonstrate distinct Raman- and fluorescence-like RIXS excitations of Bi1.5Pb0.6Sr1.54CaCu2O8+δ. Combining photon-energy and momentum dependent RIXS measurements with theoretical calculations using exact diagonalization provides conclusive evidence that the Raman-like RIXS excitations correspond to collective spin excitations, which are magnons in the undoped Mott insulators and evolve into paramagnons in doped superconducting compounds. In contrast, the fluorescence-like shifts are due primarily to the continuum of particle-hole excitations in the charge channel. Our results show that under the proper experimental conditions RIXS indeed can be used to probe paramagnons in doped high-Tc cuprate superconductors.
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3066 Pharmacokinetically (PK)-guided dosing of paclitaxel in combination with carboplatin in advanced non-small cell lung cancer (NSCLC) is gender dependent: Updated results of the randomized CEPAC-TDM study. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31708-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Direct characterization of photoinduced lattice dynamics in BaFe2As2. Nat Commun 2015; 6:7377. [PMID: 26051704 PMCID: PMC4468847 DOI: 10.1038/ncomms8377] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 04/29/2015] [Indexed: 11/16/2022] Open
Abstract
Ultrafast light pulses can modify electronic properties of quantum materials by perturbing the underlying, intertwined degrees of freedom. In particular, iron-based superconductors exhibit a strong coupling among electronic nematic fluctuations, spins and the lattice, serving as a playground for ultrafast manipulation. Here we use time-resolved X-ray scattering to measure the lattice dynamics of photoexcited BaFe2As2. On optical excitation, no signature of an ultrafast change of the crystal symmetry is observed, but the lattice oscillates rapidly in time due to the coherent excitation of an A1g mode that modulates the Fe–As–Fe bond angle. We directly quantify the coherent lattice dynamics and show that even a small photoinduced lattice distortion can induce notable changes in the electronic and magnetic properties. Our analysis implies that transient structural modification can be an effective tool for manipulating the electronic properties of multi-orbital systems, where electronic instabilities are sensitive to the orbital character of bands. In BaFe2As2, the lattice couples strongly to the magnetic and electronic degrees of freedom, providing a way to control them. Here, by means of time-resolved X-ray scattering, the authors measure rapid lattice oscillations, which can induce changes in the material's electronic and magnetic properties.
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A prospective, multi-center study of individualized, pharmacokinetically (PK)-guided dosing of 5-fluorouracil (5-FU) in metastatic colorectal cancer (mCRC) patients treated with weekly or biweekly 5-FU/oxaliplatin containing regimens. J Clin Oncol 2015. [DOI: 10.1200/jco.2015.33.15_suppl.3542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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23
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Open-label, randomized study of individualized, pharmacokinetically (PK)-guided dosing of paclitaxel combined with carboplatin in advanced non-small cell lung cancer (NSCLC) patient. J Clin Oncol 2015. [DOI: 10.1200/jco.2015.33.15_suppl.8051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Theory of Floquet band formation and local pseudospin textures in pump-probe photoemission of graphene. Nat Commun 2015; 6:7047. [PMID: 25958840 DOI: 10.1038/ncomms8047] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 03/26/2015] [Indexed: 11/09/2022] Open
Abstract
Ultrafast materials science promises optical control of physical properties of solids. Continuous-wave circularly polarized laser driving was predicted to induce a light-matter coupled state with an energy gap and a quantum Hall effect, coined Floquet topological insulator. Whereas the envisioned Floquet topological insulator requires high-frequency pumping to obtain well-separated Floquet bands, a follow-up question regards the creation of Floquet-like states in graphene with realistic low-frequency laser pulses. Here we predict that short optical pulses attainable in experiments can lead to local spectral gaps and novel pseudospin textures in graphene. Pump-probe photoemission spectroscopy can track these states by measuring sizeable energy gaps and Floquet band formation on femtosecond time scales. Analysing band crossings and pseudospin textures near the Dirac points, we identify new states with optically induced nontrivial changes of sublattice mixing that leads to Berry curvature corrections of electrical transport and magnetization.
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Phase 2 HERALD study of patritumab (P) with erlotinib (E) in advanced NSCLC subjects (SBJs). Pneumologie 2015. [DOI: 10.1055/s-0035-1544763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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A prospective randomised phase-II trial with gemcitabine versus gemcitabine plus sunitinib in advanced pancreatic cancer: a study of the CESAR Central European Society for Anticancer Drug Research-EWIV. Eur J Cancer 2014; 51:27-36. [PMID: 25459392 DOI: 10.1016/j.ejca.2014.10.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is one of the most common malignant tumours and is still associated with a poor prognosis in advanced disease. To improve the standard therapy with gemcitabine, we initiated a prospective randomised phase-II trial with gemcitabine (GEM) versus gemcitabine plus sunitinib (SUNGEM) based on data of in vitro trials and phase-I data for the combination treatment. The rational of adding sunitinib was its putative antiangiogenic mechanism of action. METHODS A total of 106 eligible patients with locally advanced, unresectable or metastatic PDAC without previous system therapy were randomised to receive GEM at a dosage of 1.000mg/m(2) d1, 8, 15 q28 versus a combination of SUNGEM at a dosage of GEM 1.000mg/m(2) d1+8 and sunitinib 50mg p.o. d1-14, q21d. The primary end-point was progression free survival (PFS), secondary end-points were overall survival (OS), toxicity and overall response rate (ORR). RESULTS The confirmatory analysis of PFS was based on the intend-to-treat (ITT) population (N=106). The median PFS was 13.3 weeks (95% confidence interval (95%-CI): 10.4-18.1 weeks) for GEM and 11.6 weeks for SUNGEM (95%-CI: 7.0-18.0 weeks; p=0.78 one-sided log-rank). The ORR was 6.1% (95%-CI: 0.7-20.2%) for GEM and for 7.1% (95%-CI: 0.9-23.5%) for SUNGEM (p=0.87). The median time to progression (TTP) was 14.0 weeks (95%-CI: 12.4-22.3 weeks) for GEM and 18.0 weeks (95%-CI: 11.3-19.3 weeks) for SUNGEM (p=0.60; two-sided log-rank). The median OS was 36.7 weeks (95%-CI: 20.6-49.0 weeks) for the GEM arm and 30.4 weeks (95%-CI: 18.1-37.6 weeks) for the SUNGEM (p=0.78, one-sided log-rank). In regard to toxicities, suspected SAEs were reported in 53.7% in the GEM arm and 71.2% in the SUNGEM arm. Grade 3 and 4 neutropenia was statistically significantly higher in the SUNGEM arm with 48.1% versus 27.8% in the GEM arm (p=0.045, two sided log-rank). CONCLUSIONS The combination SUNGEM was not sufficient superior in locally advanced or metastatic PDAC compared to GEM alone in regard to efficacy but was associated with more toxicity.
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Phase (Ph) 3 Study of Patritumab (P) Plus Erlotinib (E) in Egfr Wild-Type Subjects with Advanced Non–Small Cell Lung Cancer (Nsclc). Ann Oncol 2014. [DOI: 10.1093/annonc/mdu349.115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Dynamic competition between spin-density wave order and superconductivity in underdoped Ba1−xKxFe2As2. Nat Commun 2014; 5:3711. [DOI: 10.1038/ncomms4711] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 03/24/2014] [Indexed: 11/09/2022] Open
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Real-space visualization of remnant Mott gap and magnon excitations. PHYSICAL REVIEW LETTERS 2014; 112:156402. [PMID: 24785060 DOI: 10.1103/physrevlett.112.156402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 06/03/2023]
Abstract
We demonstrate the ability to visualize real-space dynamics of charge gap and magnon excitations in the Mott phase of the single-band Hubbard model and the remnants of these excitations with hole or electron doping. At short times, the character of magnetic and charge excitations is maintained even for large doping away from the Mott and antiferromagnetic phases. Doping influences both the real-space patterns and long timescales of these excitations with a clear carrier asymmetry attributable to particle-hole symmetry breaking in the underlying model. Further, a rapidly oscillating charge-density-wave-like pattern weakens, but persists as a visible demonstration of a subleading instability at half-filling which remains upon doping. The results offer an approach to analyzing the behavior of systems where momentum space is either inaccessible or poorly defined.
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Electron-mediated relaxation following ultrafast pumping of strongly correlated materials: model evidence of a correlation-tuned crossover between thermal and nonthermal states. PHYSICAL REVIEW LETTERS 2013; 111:077401. [PMID: 23992080 DOI: 10.1103/physrevlett.111.077401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Indexed: 06/02/2023]
Abstract
We examine electron-electron mediated relaxation following ultrafast electric field pump excitation of the fermionic degrees of freedom in the Falicov-Kimball model for correlated electrons. The results reveal a dichotomy in the temporal evolution of the system as one tunes through the Mott metal-to-insulator transition: in the metallic regime relaxation can be characterized by evolution toward a steady state well described by Fermi-Dirac statistics with an increased effective temperature; however, in the insulating regime this quasithermal paradigm breaks down with relaxation toward a nonthermal state with a complicated electronic distribution as a function of momentum. We characterize the behavior by studying changes in the energy, photoemission response, and electronic distribution as functions of time. This relaxation may be observable qualitatively on short enough time scales that the electrons behave like an isolated system not in contact with additional degrees of freedom which would act as a thermal bath, especially when using strong driving fields and studying materials whose physics may manifest the effects of correlations.
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Role of lattice coupling in establishing electronic and magnetic properties in quasi-one-dimensional cuprates. PHYSICAL REVIEW LETTERS 2013; 110:265502. [PMID: 23848894 DOI: 10.1103/physrevlett.110.265502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Indexed: 06/02/2023]
Abstract
High resolution resonant inelastic x-ray scattering has been performed to reveal the role of lattice coupling in a family of quasi-1D insulating cuprates, Ca2+5xY2-5xCu5O10. Site-dependent low-energy excitations arising from progressive emissions of a 70 meV lattice vibrational mode are resolved for the first time, providing a direct measurement of electron-lattice coupling strength. We show that such electron-lattice coupling causes doping-dependent distortions of the Cu-O-Cu bond angle, which sets the intrachain spin exchange interactions. Our results indicate that the lattice degrees of freedom are fully integrated into the electronic behavior in low-dimensional systems.
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Prospective randomized phase II trial with gemcitabine versus gemcitabine plus sunitinib in advanced pancreatic cancer: A study of the CESAR Central European Society for Anticancer Drug Research-EWIV. J Clin Oncol 2013. [DOI: 10.1200/jco.2013.31.15_suppl.4035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
4035 Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most common malignant tumours, but PDAC is still associated with a poor prognosis in advanced disease with an overall 5-year survival of only about 15%. Therefore there is a need for new treatment strategies. To improve the standard therapy with gemcitabine we initiated a prospective randomized phase-II trial with gemcitabine (GEM) vs. gemcitabine plus sunitinib (SUNGEM) based on data of in vitro trials and phase-I data for the combination treatment. Methods: Patients (N=113) with locally advanced or metastatic PDAC were prospectively randomized to receive gemcitabine alone (GEM) at a dosage of 1000 mg/m² day 1, 8, 15 q28 or to a combination of gemcitabine and sunitinib (SUNGEM) at a dosage of GEM 1000 mg/m² d1+8 and sunitinib 50mg p.o. d1-14, qd21 (based on a phase-I trial). The primary endpoint was progression-free survival (PFS), secondary endpoints were overall survival (OS), time to progression (TTP), overall response rate (ORR) and toxicity. Results: The confirmatory analysis of PFS was based on the ITT population (N=106). The median PFS was 13.3 weeks (95 %-Cl: 10.4-18.1 weeks) in the GEM group and 11.6 weeks in the SUNGEM arm (95 %-Cl: 7.0-18.0 weeks) (one-sided logrank: p=0.74). The 6-month PFS rate was 26.8 % (95 %-Cl: 15.4-39.5 %) in GEM arm and 25.0 % in SUNGEM arm (95 %-Cl: 14.0-37.8 %). The overall response rate was 6.1 % (95 %-Cl: 0.7-20.2 %) in the GEM arm and was a slightly but not significantly higher for the SUNGEM arm with 7.1% (95%-Cl: 0.9 – 23.5%).The median time to progression (TTP) was 14.0 weeks (95 %-Cl: 12.4-22.3 weeks) for the GEM arm and 18.0 weeks (95 %-Cl: 11.3-19.3 weeks) for the SUNGEM arm (two-sided logrank: p=0.60). The median OS was 30.4 weeks (95 %-Cl: 18.1-37.6 weeks) for the SUNGEM and 36.7 weeks (95 %-Cl: 20.6-49.0 weeks) for the GEM arm (two-sided logrank: p=0.44). With regard to toxicities, at least one AE of grade 3 or 4 was reported in 78.8% in the SUNGEM arm and 72.2% in the GEM arm. Conclusions: The combination of gemcitabine plus sunitinib (SUNGEM) did not improve the PFS in locally advanced or metastatic PDAC compared to gemcitabine alone. Clinical trial information: NCT00673504.
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Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La(1.75)Sr(0.25)NiO(4) nickelate crystals using time-resolved resonant x-ray diffraction. PHYSICAL REVIEW LETTERS 2013; 110:127404. [PMID: 25166848 DOI: 10.1103/physrevlett.110.127404] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Indexed: 05/19/2023]
Abstract
We investigate the order parameter dynamics of the stripe-ordered nickelate, La(1.75)Sr(0.25)NiO(4), using time-resolved resonant x-ray diffraction. In spite of distinct spin and charge energy scales, the two order parameters' amplitude dynamics are found to be linked together due to strong coupling. Additionally, the vector nature of the spin sector introduces a longer reorientation time scale which is absent in the charge sector. These findings demonstrate that the correlation linking the symmetry-broken states does not unbind during the nonequilibrium process, and the time scales are not necessarily associated with the characteristic energy scales of individual degrees of freedom.
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Competition between antiferromagnetic and charge-density-wave order in the half-filled Hubbard-Holstein model. PHYSICAL REVIEW LETTERS 2012; 109:246404. [PMID: 23368352 DOI: 10.1103/physrevlett.109.246404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Indexed: 06/01/2023]
Abstract
We present a determinant quantum Monte Carlo study of the competition between instantaneous on-site Coulomb repulsion and retarded phonon-mediated attraction between electrons, as described by the two-dimensional Hubbard-Holstein model. At half filling, we find a strong competition between antiferromagnetism (AFM) and charge-density-wave (CDW) order. We demonstrate that a simple picture of AFM-CDW competition that incorporates the phonon-mediated attraction into an effective-U Hubbard model requires significant refinement. Specifically, retardation effects slow the onset of charge order so that CDW order remains absent even when the effective U is negative. This delay opens a window where neither AFM nor CDW order is well established and where there are signatures of a possible metallic phase.
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A preliminary report of a Phase II study of folinic acid, 5-fluorouracil, irinotecan (FOLFIRI) plus sunitinib with toxicity, efficacy, pharmacokinetics, biomarker, imaging data in patients with colorectal cancer with liver metastases as 1st line treatment. Int J Clin Pharmacol Ther 2011; 49:96-98. [PMID: 21176744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
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Biomarker response on exposure to sunitinib and its primary metabolite (SU12662) in metastatic colorectal cancer patients. Int J Clin Pharmacol Ther 2011; 49:88-90. [PMID: 21176741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
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Unraveling the nature of charge excitations in La₂CuO₄ with momentum-resolved Cu K-edge resonant inelastic x-ray scattering. PHYSICAL REVIEW LETTERS 2010; 105:177401. [PMID: 21231077 DOI: 10.1103/physrevlett.105.177401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Indexed: 05/30/2023]
Abstract
The results of model calculations using exact diagonalization reveal the orbital character of states associated with different Raman loss peaks in Cu K-edge resonant inelastic x-ray scattering (RIXS) from La₂CuO₄. The model includes electronic orbitals necessary to highlight the nonlocal Zhang-Rice singlet, charge transfer, and d-d excitations, as well as states with apical oxygen 2p(z) character. The dispersion of these excitations is discussed with prospects for resonant final state wave-function mapping. A good agreement with experiments emphasizes the substantial multiorbital character of RIXS profiles in the energy transfer range 1-6 eV.
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Doping-dependent nodal fermi velocity of the high-temperature superconductor Bi2Sr2CaCu2O(8+δ) revealed using high-resolution angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2010; 104:207002. [PMID: 20867053 DOI: 10.1103/physrevlett.104.207002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Indexed: 05/29/2023]
Abstract
The improved resolution of laser-based angle-resolved photoemission spectroscopy (ARPES) allows reliable access to fine structures in the spectrum. We present a systematic, doping-dependent study of a recently discovered low-energy kink in the nodal dispersion of Bi2Sr2CaCu2O(8+δ) (Bi-2212), which demonstrates the ubiquity and robustness of this kink in underdoped Bi-2212. The renormalization of the nodal velocity due to this kink becomes stronger with underdoping, revealing that the nodal Fermi velocity is nonuniversal, in contrast with assumed phenomenology. This is used together with laser ARPES measurements of the gap velocity (v2) to resolve discrepancies with thermal conductivity measurements.
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P144 CELER: an international randomized phase III trial of the CESAR Group – or: Should chemotherapy be added to hormonal therapy in advanced breast cancer? Breast 2007. [DOI: 10.1016/s0960-9776(07)70204-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Activation of protein C following infusion of protein C concentrate in children with severe meningococcal sepsis and purpura fulminans: a randomized, double-blinded, placebo-controlled, dose-finding study. Crit Care Med 2003; 31:1839-47. [PMID: 12794428 DOI: 10.1097/01.ccm.0000072121.61120.d8] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Meningococcal septic shock in children results in high mortality and morbidity, and decreased protein C levels in these patients are associated with a poor outcome. We carried out a randomized, double-blinded, placebo-controlled study by supplying protein C concentrate. This phase 2 study was designed to assess the activation process of protein C and to study the dosing regimen of protein C concentrate in children with purpura fulminans and meningococcal septic shock in the perspective of a possible phase 3 trial. METHODS Forty children were randomized to receive placebo or protein C concentrate (200 IU/kg, 400 IU/kg, or 600 IU/kg), for a maximum of 7 days. Clinical and laboratory data, including plasma levels of protein C and activated protein C (APC), were collected at various time points. All patients received standard therapy for septic shock, including antibiotics, inotropic/vasoactive drugs, and blood products. RESULTS Increased APC levels relative to baseline were observed for the 27 of 28 patients treated with protein C concentrate, and the areas under the curve of protein C and APC were correlated with the dosage of protein C concentrate administered. Activation of coagulation, as evidenced by d-dimer levels, as well as the ratio of thrombin vs. APC normalized significantly faster with increasing dosages of protein C concentrate. No adverse reactions related to protein C concentrate were observed. Nine of the 40 (23%) patients died, and five survivors required amputations, with no differences in these rates among the randomized groups. Baseline APC levels were positively correlated with sequential organ failure assessment and pediatric risk of mortality scores and with d-dimers, tumor necrosis factor-alpha, interleukin-1, interleukin-6, interleukin-8, plasminogen activator inhibitor-1, TAT complexes, and PAP complexes. CONCLUSIONS Treatment with protein C concentrate is safe in children with purpura fulminans and meningococcal septic shock and leads to dose-related increases of plasma APC and resolution of coagulation imbalances.
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Intact T-cell regenerative capacity in childhood acute lymphoblastic leukemia after remission induction therapy. MEDICAL AND PEDIATRIC ONCOLOGY 2001; 36:283-9. [PMID: 11452936 DOI: 10.1002/1096-911x(20010201)36:2<283::aid-mpo1066>3.0.co;2-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Acute lymphoblastic leukemia (ALL) is a bone marrow disease. This may adversely affect the capacity of T cells to recover from chemotherapy-induced T-cell depletion and thus contribute to the prevailing immune deficiency in ALL patients. PROCEDURE We tested the capacity of T-cells to regenerate in 18 ALL children in first clinical remission (median age 4.2 years) at the time of hematologic reconstitution after BFM-ALL induction therapy (treatment-free interval 22 days, median; range 12 to 52 days). All patients had experienced a period of leukopenia (white blood cell count [WBC] <0.95 x 10(9)/l, median) during the final four weeks of induction therapy. T-cells and T-cell subsets were examined by FACS. RESULTS At the time of investigation the WBC was near normal (3.5 x 10(9)/l, median). Surprisingly, most cases (78%) showed a complete regeneration of T-cells and its subsets including 1) normal total (CD3+) T-cells (1635/microl, median; range 756-3440/microl); 2) normal T-helper (CD4+) cells (697/microl, median; range 128-1523/microl); and 3) normal T-cytotoxic/suppressor (CD8+) cells (686/microl, median; range 348-1540/microl). Eight patients achieved a normal CD4+/CD8+ ratio (0.8, median). Subset analyses of T-helper cells revealed a normal proportion of CD4+CD45RA+ cells (52%, median) in all but one patient below the age of 6 years, indicating an intact residual thymic activity. No correlation was observed between age at diagnosis and a normal CD4+ count (r = 0.086) or between a normal CD4+ count and a normal proportion of CD4+CD45RA+ cells r = 0.136). A long-term survey in four patients showed altered T-cells after reinduction and during maintenance therapy. CONCLUSIONS The findings suggest that ALL per se does not inhibit T-cell regenerative capacity. Thus, the frequently observed longlasting impairment of the T-cell system in ALL is attributable to the treatment rather than to the underlying disease.
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Kinetic properties of the glucose-6-phosphate and 6-phosphogluconate dehydrogenases from Corynebacterium glutamicum and their application for predicting pentose phosphate pathway flux in vivo. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:3442-52. [PMID: 10848959 DOI: 10.1046/j.1432-1327.2000.01354.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The glucose-6-phosphate (Glc6P) and 6-phosphogluconate (6PG) dehydrogenases of the amino-acid-producing bacterium Corynebacterium glutamicum were purified to homogeneity and kinetically characterized. The Glc6P dehydrogenase was a heteromultimeric complex, which consists of Zwf and OpcA subunits. The product inhibition pattern of the Glc6P dehydrogenase was consistent with an ordered bi-bi mechanism. The 6PG dehydrogenase was found to operate according to a Theorell-Chance ordered bi-ter mechanism. Both enzymes were inhibited by NADPH and the 6PG dehydrogenase additionally by ATP, fructose 1,6-bisphosphate (Fru1,6P2), D-glyceraldehyde 3-phosphate (Gra3P), erythrose 4-phosphate and ribulose 5-phosphate (Rib5P). The inhibition by NADPH was considered to be most important, with inhibition constants of around 25 microM for both enzymes. Intracellular metabolite concentrations were determined in two isogenic strains of C. glutamicum with plasmid-encoded NAD- and NADP-dependent glutamate dehydrogenases. NADP+ and NADPH levels were between 130 microM and 290 microM, which is very much higher than the respective Km and Ki values. The Glc6P concentration was around 500 microM in both strains. The in vivo fluxes through the oxidative part of the pentose phosphate pathway calculated on the basis of intracellular metabolite concentrations and the kinetic constants of the purified enzymes determined in vitro were in agreement with the same fluxes determined by NMR after 13C-labelling. From the derived kinetic model thus validated, it is concluded that the oxidative pentose phosphate pathway in C. glutamicum is mainly regulated by the ratio of NADPH and NADP+ concentrations and the specific enzyme activities of both dehydrogenases.
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Use of plasmas from donors under oral anticoagulant treatment for the expression of INR values. Haematologica 1997; 82:630-3. [PMID: 9407737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Abstract
Resistance to activated protein C (APC) diagnosed on the basis of prolongation of clotting time in an activated partial thromboplastin time (aPTT) assay is now considered a major cause of inherited thrombophilia. The majority of patients with APC resistance carry a factor V molecule with a point mutation at one APC cleavage site (Arg506Gln) which prevents the optimal inactivation of activated factor V by APC. To overcome the limitations of aPTT-based assays in the diagnosis of APC resistance, we have developed a chromogenic assay which is based on the capacity of APC to limit the generation of factor Xa by inactivating factor VIIIa in plasma. The ratio of the factor Xa amidolytic activity in a sample without APC to its factor Xa activity with the addition of APC reflects the response of the plasma coagulation system to APC. The normal range in 44 healthy individuals was 1.62-2.06. APC response ratios as measured by the chromogenic assay correlated with ratios measured by the aPTT assay and were below the normal range in 23/24 individuals with Arg506Gln mutant factor V from three different families with familial thrombosis and from 11 unrelated asymptomatic individuals. In reconstitution experiments, purified factor V corrected the decreased APC response in plasma samples from patients with the Arg506Gln mutation as well as with factor V deficiency, and increased the APC response in normal plasma, whereas the addition of activated factor V had no enhancing effect.
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A novel chromogenic assay for F.VII: Comparison to one-stage-methods. Thromb Res 1992. [DOI: 10.1016/0049-3848(92)90517-e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Entgegnung auf den Aufsatz des Herrn E. Jordis „Über Einwirkung organischer Säuren auf Antimonoxyde”. Angew Chem Int Ed Engl 1903. [DOI: 10.1002/ange.19030160205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Über die Einwirkung organischer Säuren auf metallisches Antimon. I. Z PHYS CHEM 1902. [DOI: 10.1515/zpch-1902-4115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Über Elektrolyse durch semipermeable Membranen. Z PHYS CHEM 1900. [DOI: 10.1515/zpch-1900-3334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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