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1.
Nat Commun ; 14(1): 581, 2023 Feb 03.
Article in English | MEDLINE | ID: mdl-36737608

ABSTRACT

The mysterious Planckian metal state, showing perfect T-linear resistivity associated with universal scattering rate, 1/τ = αkBT/ℏ with α ~ 1, has been observed in the normal state of various strongly correlated superconductors close to a quantum critical point. However, its microscopic origin and link to quantum criticality remains an outstanding open problem. Here, we observe quantum-critical T/B-scaling of the Planckian metal state in resistivity and heat capacity of heavy-electron superconductor Ce1-xNdxCoIn5 in magnetic fields near the edge of antiferromagnetism at the critical doping xc ~ 0.03. We present clear experimental evidences of Kondo hybridization being quantum critical at xc. We provide a generic microscopic mechanism to qualitatively account for this quantum critical Planckian state within the quasi-two dimensional Kondo-Heisenberg lattice model near Kondo breakdown transition. We find α is a non-universal constant and depends inversely on the square of Kondo hybridization strength.

2.
Proc Natl Acad Sci U S A ; 119(10): e2116980119, 2022 Mar 08.
Article in English | MEDLINE | ID: mdl-35238676

ABSTRACT

SignificanceThe elusive strange metal phase (ground state) was observed in a variety of quantum materials, notably in f-electron-based rare-earth intermetallic compounds. Its emergence has remained unclear. Here, we propose a generic mechanism for this phenomenon driven by the interplay of the gapless fermionic short-ranged antiferromagnetic spin correlation and critical bosonic charge fluctuations near a Kondo breakdown quantum phase transition. It is manifested as a fluctuating Kondo-scattering-stabilized critical (gapless) fermionic spin liquid. It shows [Formula: see text] scaling in dynamical electron scattering rate, a signature of quantum criticality. Our results on quasilinear-in-temperature scattering rate and logarithmic-in-temperature divergence in specific heat coefficient as temperature vanishes were recently seen in CePd[Formula: see text]NixAl.

3.
J Diabetes Sci Technol ; 14(5): 898-907, 2020 09.
Article in English | MEDLINE | ID: mdl-31288531

ABSTRACT

BACKGROUND: Despite the benefits and clinical necessity of insulin treatment in type 2 diabetes (T2D), healthcare providers are reluctant to initiate insulin, and patients are reluctant to start it for several reasons, one of these being the complexity of insulin treatment. Patients and their healthcare providers can benefit from titration algorithms (TAs) or rules that assist with the initiation and titration of insulin, performing the calculations that are needed to safely initiate and conservatively adjust. METHODS: The primary objective for this in silico study was to examine the effectiveness of 3 dose TAs (1-3) for optimization of basal insulin glargine (Gla-100 and Gla-300). In the simulations, 100 virtual subjects with T2D were included (50% men, age 62 ± 3 years, HbA1c 8.1% ± 2.9%, body weight 94 ± 16 kg). Subjects were studied under each TA (TA1 and TA2 fasting blood glucose [FBG] targets 90-130 mg/dL, TA3 FBG target 110-150 mg/dL). Initial dose of both insulins was based on 0.2 U/kg body weight. During 3 months, subjects reported their FBG to the LTHome web-based dose guidance system with a rules engine to safely guide long-acting insulin titration and maintenance. Subjects followed dose recommendations to reach designated FBG target ranges. RESULTS: All subjects reached stable doses under all TAs with both Gla-100 and Gla-300 insulin, and 93 or more of the 100 subjects, depending on the assigned TA, achieved the target FBG range within the 3-month simulation for all TAs. Mean FBG was lowered (Gla-100: 155 ± 40 to 118 ± 11 mg/dL with TA1 and TA2 and 132 ± 12 mg/dL for TA3; Gla-300: 125 ± 14 with TA1 and TA2 and 134 ± 15 mg/dL with TA3). Calculated HbA1c improved from 8.1% ± 2.9% to 7.1% ± 2.5% for TA1 and TA2 and 7.5% ± 2.5% for TA3, a reduction of 0.9% and 0.6% over 3 months for both insulins. Three subjects on Gla-100 and one subject on Gla-300 experienced mild hypoglycemia. CONCLUSION: All TAs delivered safe dose recommendations with minimal hypoglycemia, leading to a stable glucose control in the majority of subjects.


Subject(s)
Blood Glucose/drug effects , Computer Simulation , Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin Glargine/administration & dosage , Models, Biological , Aged , Algorithms , Biomarkers/blood , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/diagnosis , Drug Dosage Calculations , Female , Glycated Hemoglobin/metabolism , Humans , Hypoglycemia/blood , Hypoglycemia/chemically induced , Hypoglycemia/diagnosis , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/pharmacokinetics , Insulin Glargine/adverse effects , Insulin Glargine/pharmacokinetics , Male , Middle Aged , Time Factors , Treatment Outcome
4.
Sci Rep ; 6: 24102, 2016 Apr 11.
Article in English | MEDLINE | ID: mdl-27064108

ABSTRACT

There has been growing interest in searching for exotic self-conjugate, charge-neutral low-energy fermionic quasi-particles, known as Majorana fermions (MFs) in solid state systems. Their signatures have been proposed and potentially observed at edges of topological superconcuctors with non-trivial topological invariant in the bulk electronic band structure. Much effort have been focused on realizing MFs in odd-parity superconductors made of strong spin-orbit coupled materials in proximity to conventional superconductors. In this paper, we propose a novel mechanism for realizing MFs in 2D spin-singlet topological superconducting state induced by doping a correlated quantum spin Hall (Kane-Mele) insulator. Via a renormalized mean-field approach, the system is found to exhibits time-reversal symmetry (TRS) breaking d(x2-y2) + id(xy)-wave (chiral d-wave) superconductivity near half-filling in the limit of large on-site repulsion. Surprisingly, however, at large spin-orbit coupling, the system undergoes a topological phase transition and enter into a new topological phase protected by a pseudo-spin Chern number, which can be viewed as a persistent extension of the quantum spin Hall phase upon doping. From bulk-edge correspondence, this phase is featured by the presence of two pairs of counter-propagating helical Majorana modes per edge, instead of two chiral propagating edge modes in the d + id' superconductors.

5.
J Magn Reson Imaging ; 24(3): 603-10, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16878303

ABSTRACT

PURPOSE: To assess the in vitro accuracy of two rapid projective MR wave velocity measurement sequences, and their relative performance for assessing aortic stiffness in adults of all ages. MATERIALS AND METHODS: In vitro testing was performed using latex tube phantoms with precisely-known flow wave velocities, both in the presence and absence of simulated static tissue. A total of 104 adults representing a large age range (21-83 years) underwent aortic wave velocity (AWV) measurements using multiple trials of each method in a single MR session. The relative agreement between the two AWV results in each tertile of subject age and the coefficient of variation of the AWV data were assessed. RESULTS: In vitro wave velocities did not differ significantly from the known values for either MR method, with or without simulated static tissue. In vivo, the mean AWVs for the young and middle-aged cohorts did not differ significantly between the two MR methods. However, in the elderly group, the two methods did not agree, and one sequence was found to be superior in this age cohort. CONCLUSION: In elderly individuals, a one-dimensional MR method for evaluating aortic stiffness based on aortic blood displacement yields a smaller coefficient of variation and superior overall performance than a similar method based on aortic blood velocity. The two methods perform equivalently in young and middle-aged subjects.


Subject(s)
Aging , Aorta/pathology , Aortic Diseases/diagnosis , Magnetic Resonance Imaging/methods , Adult , Age Factors , Aged , Aged, 80 and over , Cohort Studies , Humans , Middle Aged , Phantoms, Imaging , Regression Analysis
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