نتایج جستجو برای: پلیمر pva
تعداد نتایج: 8266 فیلتر نتایج به سال:
Microvascular surgery is becoming a prevalent surgical practice. Replantation, hand reconstruction, orthopedic, and free tissue transfer procedures all rely on microvascular surgery for the repair of venous and arterial defects at the millimeter and submillimeter levels. Often, a vascular graft is required for the procedure as a means to bridge the gap between native arteries. While autologous ...
Diagnostic ultrasound (US) is safer, quicker and cheaper than other diagnostic imaging modalities. Over the past two decades, the applications of US imaging has been widened due to the development of injectable, compressible and encapsulated microbubbles (MBs) that provide an opportunity to improve conventional echocardiographic imaging, blood flow assessment and molecular imaging. The encapsul...
سابقه و هدف: فیلمهای بر پایه بیوپلیمر نشاسته معایبی مثل خواص مکانیکی و بازدارندگی در برابر بخار آبِ ضعیف دارند که کاربردهای آنها را در بستهبندی محدود میسازد. برای بهبود ویژگیهای فیلمهای بر پایه نشاسته، روشهای مختلفی مانند مخلوط کردن با پلیمرهای دیگر و استفاده از نانوپرکنندهها پیشنهاد شدهاند. نانوکریستال سلولز (NCC) به دلیل زیست تخریبپذیری، غیر سمی بودن، فراوانی در طبیعت، قیمت ارزان و ت...
Correspondence To the Editor: Intraatrial reentry tachycardia (IART) has been reported to occur in 2% to 10% of Mustard and Senning patients at 10 years' follow‑up. We reported a case in which the cavo‑tricuspid isthmus (CTI) in both the systemic venous atrium (SVA) and pulmonary venous atrium (PVA) was necessarily targeted in a patient following Senning operation. The patient was a 26‑year‑old...
We studied the effects of ventricular end-systolic elastance (Ees) and effective arterial elastance (Ea) on the efficiency of energy transfer from pressure-volume area (PVA) to external mechanical work (EW) in the left ventricle of anesthetized closed-chest dogs. PVA represents the total mechanical energy generated by ventricular contraction, which is an intermediate form of energy between oxyg...
this study presents the synthesis of polyvinyl acetate (pvac) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (pva) using alkaline alcoholysis. the influence of the molar ratio of hydrolysis catalyst (naoh) to pvac and the time and temperature of the saponification reaction on the degree of hydrolysis and molecular weight of the pva were investigated using response su...
Potyviruses represent the most biologically successful group of plant viruses, but to our knowledge, this work is the first detailed study of physicochemical characteristics of potyvirus virions. We measured the UV absorption, far and near UV circular dichroism spectra, intrinsic fluorescence spectra, and differential scanning calorimetry (DSC) melting curves of intact particles of a potato vir...
Modified poly(aspartic acid)/poly(vinyl alcohol) interpenetrating polymer network (KPAsp/PVA IPN) hydrogel for drug controlled release was synthesized by a simple one-step method in aqueous system using poly(aspartic acid) grafting 3-aminopropyltriethoxysilane (KH-550) and poly(vinyl alcohol) (PVA) as materials. The hydrogel surface morphology and composition were characterized by Fourier trans...
Sub-100 nm resolution local thermal analysis, X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements were used to relate surface polymer distribution with the composition of electrospun fiber mats and spin coated films obtained from aqueous dispersions of lignin, polyvinyl alcohol (PVA), and cellulose nanocrystal (CNC). Defect-free lignin/PVA fibers were produced wit...
We report the successful preparation of reinforced electrospun nanofibers and fibrous mats of polyvinyl alcohol (PVA) via a simple and inexpensive method using stable tannic acid (TA) and ferric ion (Fe+++) assemblies formed by solution mixing and pH adjustment. Changes in solution pH change the number of TA galloyl groups attached to the Fe+++ from one (pH < 2) to two (3 < pH < 6) to three (pH...
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