227 research outputs found
Entropy-driven enhanced self-diffusion in confined reentrant supernematics
We present a molecular dynamics study of reentrant nematic phases using the
Gay-Berne-Kihara model of a liquid crystal in nanoconfinement. At densities
above those characteristic of smectic A phases, reentrant nematic phases form
that are characterized by a large value of the nematic order parameter
. Along the nematic director these "supernematic" phases exhibit a
remarkably high self-diffusivity which exceeds that for ordinary, lower-density
nematic phases by an order of magnitude. Enhancement of self-diffusivity is
attributed to a decrease of rotational configurational entropy in confinement.
Recent developments in the pulsed field gradient NMR technique are shown to
provide favorable conditions for an experimental confirmation of our
simulations.Comment: 10 pages, 5 figure
The role of string-like, supramolecular assemblies in reentrant supernematic liquid crystals
Using a combination of isothermal-isobaric Monte Carlo and microcanonical
molecular dynamics we investigate the relation between structure and
self-diffusion in various phases of a model liquid crystal using the
Gay-Berne-Kihara potential. These molecules are confined to a mesoscopic
slit-pore with atomically smooth substrate surfaces. As reported recently [see
M. G. Mazza {\em et al.}, Phys. Rev. Lett. {\bf 105}, 227802 (2010)], a
reentrant nematic (RN) phase may form at sufficiently high pressures/densities.
This phase is characterized by a high degree of nematic order and a
substantially enhanced self-diffusivity in the direction of the director
which exceeds that of the lower-density nematic and an
intermittent smectic A phase by about an order of magnitude. Here we
demonstrate that the unique transport behavior in the RN phase may be linked to
a confinement-induced packing effect which causes the formation of
supramolecular, string-like conformations. The strings consist of several
individual molecules that are capable of travelling in the direction of
as individual "trains" consisting of chains of molecular "cars".
Individual trains run in parallel and may pass each other at sufficiently high
pressures.Comment: 24 page
Venous thromboembolism in multiple myeloma is associated with increased mortality
BACKGROUND: In multiple myeloma, venous thromboembolism (VTE) is common, and treatments for myeloma, such as lenalidomide, increase the risk of thrombosis while improving survival. The association between VTE and survival is not well known.
OBJECTIVES: To determine the association between VTE and survival in multiple myeloma (MM) while adjusting for known confounders that affect risk of thrombosis and survival, including patient characteristics and treatment in a retrospective cohort of US veterans.
PATIENTS/METHODS: A cohort of patients with newly diagnosed MM treated within Veterans Health Administration between September 1, 1999, and June 30, 2014, was created to assess the association between VTE and mortality using Cox proportional hazards regression modeling while accounting for known prognostic factors and treatments.
RESULTS: The cohort comprised 4446 patients with myeloma, including 2837 patients diagnosed after lenalidomide approval in July 2006. VTE occurred in 327 (7.4%) patients within 1 year and occurred at a median of 77 days (interquartile range, 37-153) after starting therapy for MM. In all patients, VTE was associated with increased mortality at 6 months (adjusted hazard ratio [aHR], 1.67; 95% confidence interval [CI], 1.18-2.37). Patients in the post-lenalidomide cohort with VTE had an increased mortality at both 6 months (aHR, 2.31; 95% CI, 1.52-3.51) and 12 months (aHR, 1.66; 95% CI, 1.19-2.33) after treatment initiation.
DISCUSSION: This study shows that VTE during the first 6-12 months of therapy is associated with increased mortality in patients with MM. Studies evaluating thromboprophylaxis in patients at high risk of thrombosis are needed
Local treatment and treatment-related adverse effects among patients with advanced prostate cancer
IMPORTANCE: Recent data suggest that local treatment with radical prostatectomy or radiation may improve survival outcomes in men with advanced prostate cancer. However, evidence is lacking on treatment-related adverse effects among men with advanced prostate cancer.
OBJECTIVE: To assess the association of local treatment on treatment-related adverse effects among men diagnosed with advanced prostate cancer.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study assessed men diagnosed with advanced prostate cancer (defined as T4, N1, and/or M1 prostate cancer) between January 1, 1999, and December 31, 2013, with follow-up through December 31, 2021, who were treated at Veterans Health Administration medical centers.
EXPOSURE: Local treatment with radical prostatectomy or radiation.
MAIN OUTCOMES AND MEASURES: Main outcomes were treatment-related adverse effects, including constitutional, gastrointestinal, pain, sexual function, and urinary function conditions, at 3 intervals after initial treatment (≤1 year, \u3e1 to ≤2 years, and \u3e2 to ≤5 years) after initial treatment.
RESULTS: This cohort study consisted of 5502 men (mean [SD] age, 68.7 [10.3] years) diagnosed with advanced prostate cancer. Of the cohort, 1705 men (31.0%) received local treatment. There was a high prevalence of adverse conditions in men receiving both local and nonlocal treatment, and these adverse conditions persisted for more than 2 years to 5 years or less after initial treatment. A total of 916 men (75.2%) with initial local treatment and 897 men (67.1%) with initial nonlocal treatment reported the presence of at least 1 adverse condition for more than 2 years to 5 years or less after initial treatment. In the first year, local treatment (vs nonlocal) was associated with adverse gastrointestinal (multivariable-adjusted odds ratio [AOR], 4.08; 95% CI, 3.06-5.45), pain (AOR, 1.57; 95% CI, 1.35-1.83), sexual (AOR, 2.96; 95% CI, 2.42-3.62), and urinary (AOR, 2.25; 95% CI, 1.90-2.66) conditions. Local treatment (without secondary treatment) remained significantly associated with adverse gastrointestinal (AOR, 2.39; 95% CI, 1.52-3.77), sexual (AOR, 3.36; 95% CI, 2.56-4.41), and urinary (AOR, 1.39; 95% CI, 1.09-1.78) conditions at more than 2 years to 5 years or less after treatment.
CONCLUSIONS AND RELEVANCE: In this cohort study of men with advanced prostate cancer, local treatment was associated with persistent treatment-related adverse effects across multiple domains. These results suggest that patients and clinicians should consider the adverse effects of local treatment when making treatment decisions in the setting of advanced prostate cancer
Inhaled medications for chronic obstructive pulmonary disease predict surgical complications and survival in stage I non-small cell lung cancer
BACKGROUND: Lung function is routinely assessed prior to surgical resection for non-small cell lung cancer (NSCLC). Further assessment of chronic obstructive pulmonary disease (COPD) using inhaled COPD medications to determine disease severity, a readily available metric of disease burden, may predict postoperative outcomes and overall survival (OS) in lung cancer patients undergoing surgery.
METHODS: We retrospectively evaluated clinical stage I NSCLC patients receiving surgical treatment within the Veterans Health Administration from 2006-2016 to determine the relationship between number and type of inhaled COPD medications (short- and long-acting beta2-agonists, muscarinic antagonists, or corticosteroids prescribed within 1 year before surgery) and postoperative outcomes including OS using multivariable models. We also assessed the relationship between inhaled COPD medications, disease severity [measured by forced expiratory volume in 1 second (FEV1)], and diagnosis of COPD.
RESULTS: Among 9,741 veterans undergoing surgery for clinical stage I NSCLC, patients with COPD were more likely to be prescribed inhaled medications than those without COPD [odds ratio (OR) =5.367, 95% confidence interval (CI): 4.886-5.896]. Increased severity of COPD was associated with increased number of prescribed inhaled COPD medications (P\u3c0.0001). The number of inhaled COPD medications was associated with prolonged hospital stay [adjusted OR (aOR) =1.119, 95% CI: 1.076-1.165), more major complications (aOR =1.117, 95% CI: 1.074-1.163), increased 90-day mortality (aOR =1.088, 95% CI: 1.013-1.170), and decreased OS [adjusted hazard ratio (aHR) =1.061, 95% CI: 1.042-1.080]. In patients with FEV1 ≥80% predicted, greater number of prescribed inhaled COPD medications was associated with increased 30-day mortality (aOR =1.265, 95% CI: 1.062-1.505), prolonged hospital stay (aOR =1.130, 95% CI: 1.051-1.216), more major complications (aOR =1.147, 95% CI: 1.064-1.235), and decreased OS (aHR =1.058, 95% CI: 1.022-1.095). When adjusting for other drug classes and covariables, short-acting beta2-agonists were associated with increased 90-day mortality (aOR =1.527, 95% CI: 1.120-2.083) and decreased OS (aHR =1.087, 95% CI: 1.005-1.177).
CONCLUSIONS: In patients with early-stage NSCLC, inhaled COPD medications prescribed prior to surgery were associated with both short- and long-term outcomes, including in patients with FEV1 ≥80% predicted. Routine assessment of COPD medications may be a simple method to quantify operative risk in early-stage NSCLC patients
Magnetic properties in ultrathin 3d transition-metal binary alloys. II. Experimental verification of quantitative theories of damping and spin pumping
A systematic experimental study of Gilbert damping is performed via ferromagnetic resonance for the disordered crystalline binary 3d transition-metal alloys Ni-Co, Ni-Fe, and Co-Fe over the full range of alloy compositions. After accounting for inhomogeneous linewidth broadening, the damping shows clear evidence of both interfacial damping enhancement (by spin pumping) and radiative damping. We quantify these two extrinsic contributions and thereby determine the intrinsic damping. The comparison of the intrinsic damping to multiple theoretical calculations yields good qualitative and quantitative agreement in most cases. Furthermore, the values of the damping obtained in this study are in good agreement with a wide range of published experimental and theoretical values. Additionally, we find a compositional dependence of the spin mixing conductance
Magnetic properties of ultrathin3dtransition-metal binary alloys. I. Spin and orbital moments, anisotropy, and confirmation of Slater-Pauling behavior
The structure and static magnetic properties-saturation magnetization, perpendicular anisotropy, spectroscopic g factor, and orbital magnetization-of thin-film 3d transition metal alloys are determined over the full range of alloy compositions via x-ray diffraction, magnetometry, and ferromagnetic resonance measurements. We determine the interfacial perpendicular magnetic anisotropy by use of samples sets with varying thickness for specific alloy concentrations. The results agreewith prior published data and theoretical predictions. They provide a comprehensive compilation of the magnetic properties of thin-film Ni-x Co1-x, Ni-x Fe1-x, and Co-x Fe1-x alloys that goes well beyond the often-cited Slater-Pauling dependence of magnetic moment on alloy concentration
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