1,496 research outputs found
Statin use and adverse effects among adults \u3e 75 years of age: Insights from the Patient and Provider Assessment of Lipid Management (PALM) registry
Background: Current statin use and symptoms among older adults in routine community practice have not been well characterized since the release of the 2013 American College of Cardiology/American Heart Association guideline. Methods and results: We compared statin use and dosing between adults \u3e75 and ≤75 years old who were eligible for primary or secondary prevention statin use without considering guideline-recommended age criteria. The patients were treated at 138 US practices in the Patient and Provider Assessment of Lipid Management (PALM) registry in 2015. Patient surveys also evaluated reported symptoms while taking statins. Multivariable logistic regression models examined the association between older age and statin use and dosing. Among 6717 people enrolled, 1704 (25%) were \u3e75 years old. For primary prevention, use of any statin or high-dose statin did not vary by age group: any statin, 62.6% in those \u3e75 years old versus 63.1% in those ≤75 years old (P=0.83); high-dose statin, 10.2% versus 12.3% in the same groups (P=0.14). For secondary prevention, older patients were slightly less likely to receive any statin (80.1% versus 84.2% [P=0.003]; adjusted odds ratio, 0.81; 95% confidence interval, 0.66-1.01 [P=0.06]), but were much less likely to receive a high-intensity statin (23.5% versus 36.2% [PP=0.0001]). Among current statin users, older patients were slightly less likely to report any symptoms (41.3% versus 46.6%; P=0.003) or myalgias (27.3% versus 33.3%; Conclusions: Overall use of statins was similar for primary prevention in those aged \u3e75 years versus younger patients, yet older patients were less likely to receive high-intensity statins for secondary prevention. Statins appear to be similarly tolerated in older and younger adult
Half-Metallic Graphene Nanoribbons
Electrical current can be completely spin polarized in a class of materials
known as half-metals, as a result of the coexistence of metallic nature for
electrons with one spin orientation and insulating for electrons with the
other. Such asymmetric electronic states for the different spins have been
predicted for some ferromagnetic metals - for example, the Heusler compounds-
and were first observed in a manganese perovskite. In view of the potential for
use of this property in realizing spin-based electronics, substantial efforts
have been made to search for half-metallic materials. However, organic
materials have hardly been investigated in this context even though
carbon-based nanostructures hold significant promise for future electronic
device. Here we predict half-metallicity in nanometre-scale graphene ribbons by
using first-principles calculations. We show that this phenomenon is realizable
if in-plane homogeneous electric fields are applied across the zigzag-shaped
edges of the graphene nanoribbons, and that their magnetic property can be
controlled by the external electric fields. The results are not only of
scientific interests in the interplay between electric fields and electronic
spin degree of freedom in solids but may also open a new path to explore
spintronics at nanometre scale, based on graphene
Patient-reported reasons for declining or discontinuing statin therapy: Insights from the PALM registry
Background: Many adults eligible for statin therapy for cardiovascular disease prevention are untreated. Our objective was to investigate patient‐reported reasons for statin underutilization, including noninitiation, refusal, and discontinuation.Methods and Results: This study included the 5693 adults recommended for statin therapy in the PALM (Patient and Provider Assessment of Lipid Management) registry. Patient surveys evaluated statin experience, reasons for declining or discontinuing statins, and beliefs about statins and cardiovascular disease risk. Overall, 1511 of 5693 adults (26.5%) were not on treatment. Of those not on a statin, 894 (59.2%) reported never being offered a statin, 153 (10.1%) declined a statin, and 464 (30.7%) had discontinued therapy. Women (relative risk: 1.22), black adults (relative risk: 1.48), and those without insurance (relative risk: 1.38) were most likely to report never being offered a statin. Fear of side effects and perceived side effects were the most common reasons cited for declining or discontinuing a statin. Compared with statin users, those who declined or discontinued statins were less likely to believe statins are safe (70.4% of current users vs. 36.9% of those who declined and 37.4% of those who discontinued) or effective (86.3%, 67.4%, and 69.1%, respectively). Willingness to take a statin was high; 67.7% of those never offered and 59.7% of patients who discontinued a statin would consider initiating or retrying a statin.Conclusions: More than half of patients eligible for statin therapy but not on treatment reported never being offered one by their doctor. Concern about side effects was the leading reason for statin refusal or discontinuation. Many patients were willing to reconsider statin therapy if offered
Measurement of low‐density lipoprotein cholesterol levels in primary and secondary prevention patients: Insights from the PALM registry
Background The 2013 American College of Cardiology/American Heart Association Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults recommended testing low-density lipoprotein cholesterol ( LDL -C) to identify untreated patients with LDL -C ≥190 mg/dL, assess lipid-lowering therapy adherence, and consider nonstatin therapy. We sought to determine whether clinician lipid testing practices were consistent with these guidelines. Methods and Results The PALM (Patient and Provider Assessment of Lipid Management) registry enrolled primary and secondary prevention patients from 140 US cardiology, endocrinology, and primary care offices in 2015 and captured demographic data, lipid treatment history, and the highest LDL -C level in the past 2 years. Core laboratory lipid levels were drawn at enrollment. Among 7627 patients, 2787 (36.5%) had no LDL -C levels measured in the 2 years before enrollment. Patients without chart-documented LDL -C levels were more often women, nonwhite, uninsured, and non-college graduates (all P\u3c0.01). Patients without prior lipid testing were less likely to receive statin treatment (72.6% versus 76.0%; P=0.0034), a high-intensity statin (21.5% versus 24.3%; P=0.016), nonstatin lipid-lowering therapy (24.8% versus 27.3%; P=0.037), and had higher core laboratory LDL -C levels at enrollment (median 97 versus 92 mg/dL; P\u3c0.0001) than patients with prior LDL -C testing. Of 166 individuals with core laboratory LDL -C levels ≥190 mg/dL, 36.1% had no LDL -C measurement in the prior 2 years, and 57.2% were not on a statin at the time of enrollment. Conclusions In routine clinical practice, LDL -C testing is associated with higher-intensity lipid-lowering treatment and lower achieved LDL -C level
Disorder, pseudospins, and backscattering in carbon nanotubes
We address the effects of disorder on the conducting properties of metal and
semiconducting carbon nanotubes. Experimentally, the mean free path is found to
be much larger in metallic tubes than in doped semiconducting tubes. We show
that this result can be understood theoretically if the disorder potential is
long-ranged. The effects of a pseudospin index that describes the internal
sublattice structure of the states lead to a suppression of scattering in
metallic tubes, but not in semiconducting tubes. This conclusion is supported
by tight-binding calculations.Comment: four page
Experimentally Engineering the Edge Termination of Graphene Nanoribbons
The edges of graphene nanoribbons (GNRs) have attracted much interest due to
their potentially strong influence on GNR electronic and magnetic properties.
Here we report the ability to engineer the microscopic edge termination of high
quality GNRs via hydrogen plasma etching. Using a combination of
high-resolution scanning tunneling microscopy and first-principles
calculations, we have determined the exact atomic structure of plasma-etched
GNR edges and established the chemical nature of terminating functional groups
for zigzag, armchair and chiral edge orientations. We find that the edges of
hydrogen-plasma-etched GNRs are generally flat, free of structural
reconstructions and are terminated by hydrogen atoms with no rehybridization of
the outermost carbon edge atoms. Both zigzag and chiral edges show the presence
of edge states.Comment: 16+9 pages, 3+4 figure
First direct observation of Dirac fermions in graphite
Originating from relativistic quantum field theory, Dirac fermions have been
recently applied to study various peculiar phenomena in condensed matter
physics, including the novel quantum Hall effect in graphene, magnetic field
driven metal-insulator-like transition in graphite, superfluid in 3He, and the
exotic pseudogap phase of high temperature superconductors. Although Dirac
fermions are proposed to play a key role in these systems, so far direct
experimental evidence of Dirac fermions has been limited. Here we report the
first direct observation of massless Dirac fermions with linear dispersion near
the Brillouin zone (BZ) corner H in graphite, coexisting with quasiparticles
with parabolic dispersion near another BZ corner K. In addition, we report a
large electron pocket which we attribute to defect-induced localized states.
Thus, graphite presents a novel system where massless Dirac fermions,
quasiparticles with finite effective mass, and defect states all contribute to
the low energy electronic dynamics.Comment: Nature Physics, in pres
Role of export industries on ozone pollution and its precursors in China
This study seeks to estimate how global supply chain relocates emissions of tropospheric ozone precursors and its impacts in shaping ozone formation. Here we show that goods produced in China for foreign markets lead to an increase of domestic non-methane volatile organic compounds (NMVOCs) emissions by 3.5 million tons in 2013; about 13% of the national total or, equivalent to half of emissions from European Union. Production for export increases concentration of NMVOCs (including some carcinogenic species) and peak ozone levels by 20–30% and 6–15% respectively, in the coastal areas. It contributes to an estimated 16,889 (3,839–30,663, 95% CI) premature deaths annually combining the effects of NMVOCs and ozone, but could be reduced by nearly 40% by closing the technology gap between China and EU. Export demand also alters the emission ratios between NMVOCs and nitrogen oxides and hence the ozone chemistry in the east and south coast
Genetic Vaccination-Induced Immune Responses to the Human Immunodeficiency Virus Protein Rev: Emergence of the Interleukin 2-Producing Helper T Lymphocyte
Overview summary The immune system poses a major obstacle to the long-term success of in vivo gene therapies. Immune responses to foreign transgene products and/or the vectors that facilitate gene transfer may neutralize the transgene product, eliminate transfected cells, and culminate in inflammation within transfected tissues. The majority of studies that address these issues have focused on cytotoxic T lymphocyte (CTL) and antibody responses induced by gene transfer. However, the IL-2-producing helper T lymphocyte (HTL) represents a critical regulatory cell that likely influences the inductive phase of the immune response following gene transfer. The current study employed limiting dilution analysis (LDA) techniques to characterize the development of IL-2-producing HTLs induced by genetic vaccination with a plasmid encoding the mutated HIV protein Rev M10. Further, we assessed the ability to inhibit the transgene-induced HTL response by cotransfer of a plasmid encoding the immunosuppressive cytokine TGFβ1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63282/1/hum.1998.9.15-2187.pd
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