2,613 research outputs found
Flexible composite film for printed circuit board
A flexible printed circuit for a printed circuit board in which layers of reaction product composed of a combination of phenoxy resin - polyisocyanate - brominated epoxy resin, and in which the equivalent ratio of those functional groups is hydroxyl group: isocyanate group: epoxy group - 1 : 0.2 to 2 : 0.5 to 3 are laminated on at least one side of saturated polyester film is discussed
Accurate description of bulk and interfacial properties in colloid-polymer mixtures
Large-scale Monte Carlo simulations of a phase-separating colloid-polymer
mixture are performed and compared to recent experiments. The approach is based
on effective interaction potentials in which the central monomers of
self-avoiding polymer chains are used as effective coordinates. By
incorporating polymer nonideality together with soft colloid-polymer repulsion,
the predicted binodal is in excellent agreement with recent experiments. In
addition, the interfacial tension as well as the capillary length are in
quantitative agreement with experimental results obtained at a number of points
in the phase-coexistence region, without the use of any fit parametersComment: 4 pages, 4 figure
Entropic torque
Quantitative predictions are presented of a depletion-induced torque and
force acting on a single colloidal hard rod immersed in a solvent of hard
spheres close to a planar hard wall. This torque and force, which are entirely
of entropic origin, may play an important role for the key-lock principle,
where a biological macromolecule (the key) is only functional in a particular
orientation with respect to a cavity (the lock)
Rosenfeld functional for non-additive hard spheres
The fundamental measure density functional theory for hard spheres is
generalized to binary mixtures of arbitrary positive and moderate negative
non-additivity between unlike components. In bulk the theory predicts
fluid-fluid phase separation into phases with different chemical compositions.
The location of the accompanying critical point agrees well with previous
results from simulations over a broad range of non-additivities and both for
symmetric and highly asymmetric size ratios. Results for partial pair
correlation functions show good agreement with simulation data.Comment: 8 pages with 4 figure
Entropy-induced Microphase Separation in Hard Diblock Copolymers
Whereas entropy can induce phase behavior that is as rich as seen in
energetic systems, microphase separation remains a very rare phenomenon in
entropic systems. In this paper, we present a density functional approach to
study the possibility of entropy-driven microphase separation in diblock
copolymers. Our model system consists of copolymers composed of freely-jointed
slender hard rods. The two types of monomeric segments have comparable lengths,
but a significantly different diameter, the latter difference providing the
driving force for the phase separation. At the same time these systems can also
exhibit liquid crystalline phases. We treat this system in the appropriate
generalization of the Onsager approximation to chain-like particles. Using a
linear stability (bifurcation) analysis, we analytically determine the onset of
the microseparated and the nematic phases for long chains. We find that for
very long chains the microseparated phase always preempts the nematic. In the
limit of infinitely long chains, the correlations within the chain become
Gaussian and the approach becomes exact. This allows us to define a Gaussian
limit in which the theory strongly simplifies and the competition between
microphase separation and liquid crystal formation can be studied essentially
analytically. Our main results are phase diagrams as a function of the
effective diameter difference, the segment composition and the length ratio of
the segments. We also determine the amplitude of the positional order as a
function of position along the chain at the onset of the microphase separation
instability. Finally, we give suggestions as to how this type of
entropy-induced microphase separation could be observed experimentally.Comment: 16 pages, 7 figure
HPV Vaccine Acceptability Among Men: A Systematic Review and Meta-Analysis
Objective To understand rates of human papillomavirus (HPV) vaccine acceptability and factors correlated with HPV vaccine acceptability. Design Meta-Analyses of cross-sectional studies. Data sources We used a comprehensive search strategy across multiple electronic databases with no date or language restrictions to locate studies that examined rates and/or correlates of HPV vaccine acceptability. Search keywords included vaccine, acceptability and all terms for HPV. Review methods We calculated mean HPV vaccine acceptability across studies. We conducted meta-Analysis using a random effects model on studies reporting correlates of HPV vaccine acceptability. All studies were assessed for risk of bias. Results Of 301 identified studies, 29 were included. Across 22 studies (n=8360), weighted mean HPV vaccine acceptability=50.4 (SD 21.5) (100-point scale). Among 16 studies (n=5048) included in meta-Analyses, perceived HPV vaccine benefits, anticipatory regret, partner thinks one should get vaccine and healthcare provider recommendation had medium effect sizes, and the following factors had small effect sizes on HPV vaccine acceptability: perceived HPV vaccine effectiveness, need for multiple shots, fear of needles, fear of side effects, supportive/accepting social environment, perceived risk/susceptibility to HPV, perceived HPV severity, number of lifetime sexual partners, having a current sex partner, non-receipt of hepatitis B vaccine, smoking cigarettes, history of sexually transmitted infection, HPV awareness, HPV knowledge, cost, logistical barriers, being employed and non-white ethnicity. Conclusions Public health campaigns that promote positive HPV vaccine attitudes and awareness about HPV risk in men, and interventions to promote healthcare provider recommendation of HPV vaccination for boys and mitigate obstacles due to cost and logistical barriers may support HPV vaccine acceptability for men. Future investigations employing rigorous designs, including intervention studies, are needed to support effective HPV vaccine promotion among men
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