Solution
blends of poly(l-lactic acid) (PLLA) and poly(3-hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) in chloroform/DMF were electrospun
at room temperature on a stationary collection plate. Polymer blend
ratio, PHBV hydroxyvalerate content, solvent ratio, polymer concentration,
and electrospinning process parameters were varied to determine optimal
electrospinning conditions. The success of each formulation at producing
nonwoven mats of continuous submicron diameter fibers was evaluated
by optical and scanning electron microscopy. The diameter of the blend
fibers was larger than electrospun fibers of either neat electrospun
polymer, with a higher PLLA ratio favoring a porous surface morphology
and higher PHBV ratios favoring beaded fiber morphology. Differential
scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were
used to analyze the thermal properties of the fibrous mats. The glass
transition temperatures of the fibers from blends decreased as the
PHBV weight ratio increased. The crystallinity of the PHBV fraction
decreased as the ratio of the polymer in the blend decreased, whereas
the crystallinity of PLLA was unaffected by the blend ratio. Dynamic
mechanical analysis (DMA) indicated that the tensile strength of electrospun
PHBV was improved by blending. Porous PLLA/PHBV electrospun fibers
have potential for applications that need a high surface to volume
ratio such as filtration, biomedical, energy storage devices, etc.
This paper investigates the adpositional marking and case marking systems in Lutuv. This investigation finds that the basic adpositional phrase consists of a noun and a simplex or complex postposition. Complex postpositions are often used to convey information about both movement and location, whereas simplex postpositions are usually limited to expressing one of the two. The findings of this investigation are useful for highlighting potential future areas of research in Lutuv.
This secondary analysis quantified the psychometric properties of the Ohio Modified Arm-Motor Ability Test (OMAAT) in a sample of neurologically stable chronic stroke survivors (n = 67, 40 men; mean age 59.8 yr, standard deviation = 12.8; 42 White, 23 Black, 2 other; 92.5% right-sided lesion; 44 ischemic stroke). Findings indicate high OMAAT internal consistency (Cronbach's α = .97, ordinal α = .98, Gugiu's bootstrap reliability = .97), unidimensionality, and strong positive factor loadings for all 20 OMAAT items. Convergent validity between OMAAT and Action Research Arm Test total scores was strong (r = .90, p < .0001). The OMAAT is the first short measure of upper extremity functional limitation available to clinicians and researchers that includes an administration manual and that has been examined using nonparametric psychometrics. A detailed administration manual is provided as a supplement to this article.
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