We report aqueous, room temperature RAFT polymerization of N-isopropylacrylamide (NIPAM) and, subsequently, its block copolymerization utilizing a poly(N,N-dimethylacrylamide) macro-CTA. A series thermally responsive AB diblock and ABA triblock copolymers have been prepared. These polymers contain hydrophilic N,N-dimethylacrylamide (DMA) blocks fixed molecular weight temperature-responsive NIPAM B varied chain length. Using combination 1H NMR spectroscopy, T2 relaxation measurements, dynamic...

Poly(N-isopropyl acrylamide) is a thermoresponsive polymer that has been widely investigated for drug delivery. Herein, we report conditions facilitating the controlled, room-temperature RAFT polymerization of N-isopropylacrylamide (NIPAM). The key to success appropriate choice both suitable chain transfer agent (CTA) and initiating species. We show use 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid, trithiocarbonate CTA, in conjunction with azo initiator...

We report a facile labeling technique in which the telechelic thiocarbonylthio functionality of well-defined poly(N-isopropylacrylamide) (PNIPAM) prepared by room temperature RAFT polymerization is first converted to thiol and subsequently reacted with maleimido-functional fluorescent dye, N-(1-pyrene)maleimide (PM). Nearly monodisperse PNIPAM (Mn = 39 500 g/mol, Mw/Mn 1.07) was synthesized using trithiocarbonate-based CTA, 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP),...

Poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) is a nonimmunogenic, neutral-hydrophilic polymer currently employed in the delivery of anticancer drugs. Herein, we report conditions that facilitate direct, controlled RAFT polymerization HPMA aqueous media. We demonstrate use 4-cyanopentanoic acid dithiobenzoate and 4,4'-azobis(4-cyanopentanoic acid) as chain transfer agent (CTA) initiating species, respectively, presence an acetic buffer solution at 70 °C suitable condition leading to...

The reversible addition−fragmentation chain transfer (RAFT) polymerization of acrylamide (AM) was studied in order to establish reaction conditions which would provide optimal rates monomer conversion and determine reasons for deviation theoretical experimental molecular weights, the former predicted from current models. To this end, agents (CTAs) initiators were selected experiments performed water dimethyl sulfoxide (DMSO) at specified CTA/initiator ratios temperatures. Higher apparent...

Controlled radical polymerization (CRP) combines the benefits of robust nature conventional with ability to prepare advanced macromolecular architectures common living techniques. Of major CRP techniques, reversible addition−fragmentation chain transfer (RAFT) technique appears be most tolerant aqueous reaction conditions and a variety monomer functionalities. To date, however, there have been no reports RAFT cationic (meth)acrylamido directly in media. Herein we report...

Abstract Summary: The first example of a room temperature reversible addition‐fragmentation chain transfer polymerization conducted directly in aqueous media is detailed. Under these conditions acrylamide and N , ‐dimethylacrylamide may be polymerized controlled fashion to near quantitative conversions employing difunctional trithiocarbonate agent (CTA). Hydrolysis studies at pH 5.5 suggest that the CTA stable up approximately 50 °C. magnified image

We describe a facile method to amine functionalize and subsequently fluorescently label polymethacrylamides synthesized via reversible addition−fragmentation chain transfer (RAFT) polymerization. RAFT-generated poly(N-(2-hydroxypropyl) methacrylamide-b-N-[3-(dimethylamino)propyl] methacrylamide) (poly(HPMA-b-DMAPMA)), water soluble biocompatible polymer, is first converted polymeric thiol functionalized with primary through disulfide exchange reaction cystamine reacted the...

Biomaterials used in the ocular environment should exhibit specific tribological behavior to avoid discomfort and stress-induced epithelial damage during blinking. In this study, two macromolecules that are commonly employed as biomaterials, namely, poly(vinylpyrrolidone) (PVP) hyaluronan (HA), compared with known model glycoproteins, namely bovine submaxillary mucin (BSM) α1-acid glycoprotein (AGP), regard their nonfouling efficiency, wettability, properties when freely present lubricant,...

The complexation of small interfering ribonucleic acid (siRNA) with a series specifically designed block copolymers consisting the hydrophilic, nonimmunogenic monomer N-(2-hydroxypropyl)methacrylamide (HPMA) and cationic N-[3-(dimethylamino)propyl]methacrylamide (DMAPMA) has been investigated for potential siRNA stabilization delivery applications. Specific compositions poly(HPMA-b-DMAPMA) were synthesized via aqueous reversible addition−fragmentation chain transfer (RAFT) polymerization...

The coefficient of friction (CoF) has been reported to correlate with clinical comfort soft contact lenses (SCL). However, a classification in terms CoF is not always applicable materials, such as hydrogels, due the frequently observed nonlinearity between lateral and normal forces. An alternative methodology presented quantify tribological characteristics materials under boundary lubrication average work. Average work was derived from knowledge area contact, interfacial shear stress,...

Poly(methacrylic acid) (PMA) and poly(ethylene glycol) (PEG) represent a polyacid/polybase pair capable of forming reversible, pH-responsive, hydrophobic complexes stabilized by hydrogen bonding in aqueous media. Linear PMA was modified with methoxy-terminated, long-chain (5000 Mw) (MPEG) via random coupling dimethyl sulfoxide using dicyclohexylcarbodiimide as agent. The degree ionization, α, deteremined utilizing potentiometric titration. presence tethered MPEG markedly increased the pKa...

Abstract The polymerization of methacrylamide (MAM) was performed in aqueous media via reversible addition fragmentation chain transfer (RAFT) with the dithiobenzoate chain‐transfer agent (CTA) 4‐cyanopentanoic acid (CTP) and 4,4′‐azobis(4‐cyanopentanoic acid) (V‐501) as initiator. unbuffered water at 70 °C a CTP/V‐501 ratio 1.5 controlled for first 3 h, after which molecular weight distribution broadened substantial deviation experimental from theoretical occurred, presumably because loss...

Dynamic thin film interferometry is a technique used to non-invasively characterize the thickness of liquid films. Recovering underlying from captured interferograms, unconditionally and automatically still an open problem. Here we report compact setup employing snapshot hyperspectral camera related algorithms for automated determination profiles dynamic The proposed shown recover within 100 nm accuracy as compared those reconstructed through manual color matching process. Subsequently,...

Background Identification and referral of at-risk patients from primary care practitioners (PCPs) to eye professionals remain a challenge. Approximately 1.9 million Americans suffer vision loss as result undiagnosed or untreated ophthalmic conditions. In ophthalmology, artificial intelligence (AI) is used predict glaucoma progression, recognize diabetic retinopathy (DR), classify ocular tumors; however, AI has not yet been triage for ophthalmology referral. Objective This study aimed build...

SIGNIFICANCE Optimal meibography utilization and interpretation are hindered due to poor lid presentation, blurry images, or image artifacts the challenges of applying clinical grading scales. These results, using largest dataset analyzed date, demonstrate development algorithms that provide standardized, real-time inference addresses all these limitations. PURPOSE This study aimed develop validate an algorithmic pipeline automate standardize meibomian gland absence assessment...

Purpose: Contact lens–induced discomfort (CLD) remains a primary factor in discontinuation or prevention of contact lens wear. Thus, we investigated the role ocular surface immune cells subjects with CLD. Methods: Habitual (CL) wearers CLD (n = 19; 38 eyes) and without 21; 42 as determined by Lens Dry Eye Questionnaire-8 was included trial. Enrolled used either two types CL (designated CL-A CL-D). Ocular from bulbar conjunctiva were obtained impression cytology. The collected phenotyped...

Abstract Purpose To present the objective metrics from a study that evaluated clinical performance of senofilcon A contact lens, both with and without new manufacturing technique. Methods This was single‐site, five‐visit, controlled, randomised, subject‐masked, 2 × crossover (May–August 2021) 2‐week lens dispensing period (bilateral wear) weekly follow‐up visits. Healthy adult (18–39 years), habitual spherical silicone hydrogel wearers were included. The High‐definition (HD) Analyzer™ used...

Purpose: To quantify the effect of silicone hydrogel crosslink density on adhesion at corneal epithelial cells/silicone contact lens interface. Methods: A custom-built rheometer, referred to as live cell monolayer was used measure adhesive strengths between monolayers and surfaces. The resulting stress relaxations senofilcon A–derived materials with varying crosslinking densities delefilcon were tested. Senofilcon A–like labeled L1, L2, L3, L4, L5 contained crosslinker concentrations 1.2,...

The deposition profile of cholesteryl ester on the surface and throughout matrix silicone hydrogel contact lens (CL) materials was determined under conditions that mimic a daily wear regimen.In this in vitro study, four SiHy CL (senofilcon C, lotrafilcon B, comfilcon A samfilcon A) were incubated an artificial tear solution (ATS) for up to 30 days. incubation alternated between ATS (16 hours) multipurpose care regimen (8 hours). included fluorescently tagged (5-cholesten-3ß-ol...

You have accessJournal of UrologyStone Disease: Surgical Therapy II1 Apr 2016PD18-11 COMPARISON OF AN ELECTRIC PULSE LITHOTRIPTER TO THE HOLMIUM LASER: STONE FRAGMENTATION EFFICIENCY AND IMPACT ON FLEXIBLE URETEROSCOPE DEFLECTION FLOW Adam Kaplan, Tony Chen, Richard Shin, Joanne Dale, Fernando Cabrera, Daniela Radvak, Anika Ackerman, Georgy Sankin, Pei Zhong, Charles Scales, Jr., Michael Ferrandino, Neal Simmons, Glenn Preminger, and Lipkin KaplanAdam Kaplan More articles by this author ,...

You have accessJournal of UrologyStone Disease: New Technology II1 Apr 2014PD37-04 BALL-TIP HOLMIUM LASER FIBER: IN VITRO STONE COMMINUTION AND FIBER TIP DEGRADATION Richard Shin, Jaclyn Lautz, Fernando Cabrera, Zachariah Goldsmith, Nicholas Kuntz, Ramy Youssef, Andreas Neisius, Charles Scales, Michael Ferrandino, Pei Zhong, Walter Simmons, Glenn Preminger, and Lipkin ShinRichard Shin More articles by this author , LautzJaclyn Lautz CabreraFernando Cabrera GoldsmithZachariah Goldsmith...

You have accessJournal of UrologyStone Disease: Surgical Therapy IV1 Apr 2017PD35-09 COMPARISON OF A NOVEL SINGLE-USE FLEXIBLE URETEROSCOPE TO CURRENTLY EXISTING REUSABLE AND URETEROSCOPES Daniel Wollin, Ruiyang Jiang, Daniela Radvak, Charles Scales, Michael Ferrandino, W Neal Simmons, Glenn Preminger, and Lipkin WollinDaniel Wollin More articles by this author , JiangRuiyang Jiang RadvakDaniela Radvak ScalesCharles Scales FerrandinoMichael Ferrandino SimmonsW Simmons PremingerGlenn...