Theory of the optical properties of non-absorbing compensated cholesteric liquid crystals

A theory is developed of the optical properties of a non-absorbing compensated cholesteric liquid crystal. It is shown that the Mauguin-de Vries equation fails when the pitch becomes very large. Theoretical curves are presented of the dependence of the rotatory power on pitch for different values of the sample thickness. The results are in agreement with the observed variation of the rotatory power of a compensated cholesteric mixture with temperature

Thermomechanical effect in cholesteric liquid crystals

We discuss some possible experimental geometries for studying Leslie's thermomechanical effect in cholesteric liquid crystals. The discussion includes the effect of a temperature gradient (i) along and (ii) perpendicular to the helical axis. The feasibility of observing the effect and of extracting the thermomechanical coefficients is examined

Flow of cholesteric liquid crystals-I: Flow along the helical axis

It is shown that the essential features of Helfrich's penneation model for flow along the helical axis of a cholesteric liquid crystal can be derived approximately on the basis of the Ericksen-Leslie theory

Evidence for structural and electronic instabilities at intermediate temperatures in κ\kappa-(BEDT-TTF)2_{2}X for X=Cu[N(CN)2_{2}]Cl, Cu[N(CN)2_{2}]Br and Cu(NCS)2_{2}: Implications for the phase diagram of these quasi-2D organic superconductors

We present high-resolution measurements of the coefficient of thermal expansion $\alpha (T)=\partial \ln l(T)/\partial T$ of the quasi-twodimensional (quasi-2D) salts $\kappa$-(BEDT-TTF)$_2$X with X = Cu(NCS)$_2$, Cu[N(CN)$_2$]Br and Cu[N(CN)$_2$]Cl. At intermediate temperatures (B), distinct anomalies reminiscent of second-order phase transitions have been found at $T^\ast = 38$ K and 45 K for the superconducting X = Cu(NCS)$_2$ and Cu[N(CN)$_2$]Br salts, respectively. Most interestingly, we find that the signs of the uniaxial pressure coefficients of $T^\ast$ are strictly anticorrelated with those of $T_c$. We propose that $T^\ast$ marks the transition to a spin-density-wave (SDW) state forming on minor, quasi-1D parts of the Fermi surface. Our results are compatible with two competing order parameters that form on disjunct portions of the Fermi surface. At elevated temperatures (C), all compounds show $\alpha (T)$ anomalies that can be identified with a kinetic, glass-like transition where, below a characteristic temperature $T_g$, disorder in the orientational degrees of freedom of the terminal ethylene groups becomes frozen in. We argue that the degree of disorder increases on going from the X = Cu(NCS)$_2$ to Cu[N(CN)$_2$]Br and the Cu[N(CN)$_2$]Cl salt. Our results provide a natural explanation for the unusual time- and cooling-rate dependencies of the ground-state properties in the hydrogenated and deuterated Cu[N(CN)$_2$]Br salts reported in the literature.Comment: 22 pages, 7 figure

On the ``inverse'' isotope effect in organic superconductors: New findings and implications

The inverse deuterium isotope effect, previously found in K-(BEDT-TTF){sub 2}CU(NCS){sub 2}, is also found in two other BEDT-TTF-based superconductors with different packing motifs and different types of anions. Remarkably, the magnitude of the isotope shift is essentially identical in all three superconductors, ca. +0.26 {+-} 0.06 K. These results, when taken together with the recent results of Lang et al. on the uniaxial pressure derivatives of T{sub c}, suggest that the inverse isotope effect may not have a direct relationship to the pairing mechanism but instead is a reflection of the change in the internal lattice pressure

Isotope effect in BEDT-TTF based organic superconductors

The results of the comprehensive isotope effect studies, in which seven different isotopically labeled (involving {sup 13}C, {sup 34}S and {sup 2}H labeling) BEDT-TTF derivatives and isotopically labeled anion [Cu({sup 15}N{sup 13}CS){sub 2}]{sup {minus}} were utilized, are summarized. For the first time, convincing evidence for a genuine BCS-like mass isotope effect in an organic superconductor is revealed in these studies

White Blood Cell Count and Major Adverse Cardiovascular Events After Percutaneous Coronary Intervention in the Contemporary Era: Insights From the PARIS Study (Patterns of Non-Adherence to Anti-Platelet Regimens in Stented Patients Registry).

Elevated white blood cell (WBC) count is associated with increased major adverse cardiovascular events (MACE) in the setting of acute coronary syndrome. The aim of this study was to evaluate whether similar associations persist in an all-comers population of patients undergoing percutaneous coronary intervention in the contemporary era. In the multicenter, prospective, observational PARIS study (Patterns of Non-Adherence to Anti-Platelet Regimens in Stented Patients Registry), 4222 patients who underwent percutaneous coronary intervention in the United States and Europe between July 1, 2009, and December 2, 2010, were evaluated. The associations between baseline WBC and MACE (composite of cardiac death, stent thrombosis, spontaneous myocardial infarction, or target lesion revascularization) at 24-month follow-up were analyzed using multivariable Cox regression. Patients with higher WBC were more often younger, smokers, and with less comorbid risk factors compared with those with lower WBC. After adjustment for baseline and procedural characteristics, WBC remained independently associated with MACE (hazard ratio [HR] per 10(3) cells/μL increase, 1.05 [95% confidence intervals (CI), 1.02-1.09]; P=0.001), cardiac death (HR, 1.10 [95% CI, 1.05-1.17]; P<0.001), and clinically indicated target revascularization (HR, 1.04 [95% CI, 1.00-1.09]; P=0.03) but not stent thrombosis (HR, 1.07 [95% CI, 0.99-1.16]; P=0.10) or spontaneous myocardial infarction (HR, 1.03 [95% CI, 0.97-1.09]; P=0.29). The association between WBC and MACE was consistent in acute coronary syndrome and non-acute coronary syndrome presentations (interaction P=0.15). Increased WBC is an independent predictor of MACE after percutaneous coronary intervention in a contemporary all-comers cohort. Further studies to delineate the underlying pathophysiologic role of elevated WBC across a spectrum of coronary artery disease presentations are warranted. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00998127

A Retrospective Look at the Monitoring and Checking (MaC) Framework

The Monitoring and Checking (MaC) project gave rise to a framework for runtime monitoring with respect to formally specified properties, which later came to be known as runtime verification. The project also built a pioneering runtime verification tool, Java-MaC, that was an instantiation of the approach to check properties of Java programs. In this retrospective, we discuss decisions made in the design of the framework and summarize lessons learned in the course of the project