The quasi-one-dimensional conductor (NH4), [Pt(CN)4]C104, . 3H,O, ACP(C1), has been studied experimentally by means of electrical conduction measurements, x-ray diA'use scattering, and neutron inelastic scattering. This allows the determination of all the physical parameters of interest for the theoretical description of the way, in which the Peierls instability manifests itself. ACP(C1) appears as an analog of the well-studied isostructural compound K2[Pt(CN)4]Bro, 3H,O, KCP(Br), with three major changes. First, an increased intrachain Pt-distance in ACP(Cl) causes the metallic conductivity cr to drop, and second, an increased Fermi wave vector kF introduces a change in the electron-phonon coupling constant X via the bare phonon frequency co(2kF). Third, the interchain coupling q is enhanced in ACP(C1), which seems to be related to the hydrogen bonding of the NH4+ ions. We also present and discuss the frequency dependence of the conductivity at frequencies up to 1 MHz.
The study's aim is to compare current and new equations for estimating glomerular filtration rate (GFR) based on creatinine, cystatin C, β-trace protein (BTP) and β2 microglobulin (B2M) among patients undergoing major amputation.Methods: This is a secondary analysis of data from a prospective cohort study investigating patients undergoing nontraumatic lower extremity amputation. Estimated GFR (eGFR) was calculated using equations based on creatinine (eGFRcre[2009] and eGFRcre [2021]), cystatin C (eGFRcys), the combination of creatinine and cystatin C (eGFRcomb [2012] and eGFRcomb [2021]) or a panel of all 4 filtration markers (eGFRpanel). Primary outcome was changed in eGFR across amputation according to each equation. Two case studies of prior amputation with GFR measured by 99mTc-DTPA clearance are described to illustrate the relative accuracies of each eGFR equation.Results: Analysis of the primary outcome included 29 patients (median age 75 years, 31% female). Amputation was associated with a significant decrease in creatinine concentration (À0.09 mg/dL, P = 0.004), corresponding to a significant increase in eGFRcre [2009] (+6.1 mL/min, P = 0.006) and eGFRcre[2021] (+6.3 mL/min, P = 0.006). Change across amputation was not significant for cystatin C, BTP, B2M or equations incorporating these markers (all P > 0.05). In both case studies, eGFRcre[2021] yielded the largest positive bias, eGFRcys yielded the largest negative bias and eGFRcomb [2012] and eGFRcomb [2021] yielded the smallest absolute bias.
Conclusion:Creatinine-based estimates were substantially higher than cystatin Cbased estimates before amputation and significantly increased across amputation.Estimates combining creatinine and cystatin were stable across amputation, while the addition of BTP and B2M is unlikely to be clinically relevant.Esben Iversen and Anne Byriel Walls share first authorship.
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