Research into mosquito-borne illnesses faces hurdles because feeding fresh animal blood to rear female mosquitoes presents logistical, economic, and safety challenges. In this study, a shelf-stable additive (spray-dried porcine blood; SDPB) hypothesized to supply accessible hemoglobin was evaluated within an alternative meal (AM) containing whey powder and PBS for rearing the yellow fever mosquito Aedes aegypti. LC–MS/MS proteomics, microbial assays, and particle reduction techniques confirmed and characterized the functionality of hemoglobin in SDPB, while engorgement, fecundity, egg viability, and meal stability bioassays assessed AM performance. Chemical assays supported hemoglobin as the phagostimulant in SDPB with aggregates partially solubilized in the AM that can be more accessible via particle reduction. Unpaired two-tailed t-tests indicate that the AM stimulates oogenesis (t11 = 13.6, p = 0.003) and is stable under ambient (1+ y; t12 = 0.576, p = 0.575) and aqueous (14 d; t12 = 0.515, p = 0.639) conditions without decreasing fecundity. Egg hatch rates for the ninth generation of AM-reared Ae. aegypti were 50–70+%. With further development, this meal may serve as a platform for mass rearing or studying effects of nutritional additives on mosquito fitness due to its low cost and stability. Future work may examine tuning spray drying parameters and resulting impacts on hemoglobin agglomeration and feeding.

Mosquitoes can impact military operational readiness by transmission of disease-causing pathogens or through secondary effects, e.g., annoyance and bites. The focus of this research was to determine if an array of novel controlled release passive devices (CRPD) utilizing the spatial repellent, transfluthrin (TF), as the active ingredient could prevent entry of mosquitoes into military tents for up to 4 weeks. The TF-charged CRPDs were spaced along six strands of monofilament and hung across the tent entrance. Efficacy was evaluated with caged Aedes aegypti to indicate knockdown/mortality effects, and four species of free-flying mosquitoes, Ae. aegypti, Aedes taeniorhynchus, Anopheles quadrimaculatus and Culex quinquefasciatus, to indicate repellent effects. Bioassay cages containing Ae. aegypti were hung vertically at 0.5, 1.0 and 1.5 ​m above ground level at designated locations inside of the tents. Knockdown/mortality counts were made every 15 min for the first hour, then at 2, 4 and 24 h post-exposure. Free fliers were recaptured in BG traps operated from 4 to 24 h post-exposure. Knockdown/mortality was gradual until 4 h post-exposure. This increased to near 100% by 24 h in the treated tent but was < 2% in the control tent. There was a significant reduction in the recapture rates of all free-flying species in the treated tent compared with the control tent. Results indicate that TF-charged CRPDs can significantly reduce the numbers of mosquitoes entering military tents and that the four species were affected similarly by the TF. The needs for additional research are discussed.

Mosquitoes can impact military operational readiness by transmission of disease-causing pathogens or through secondary effects, e.g., annoyance and bites. The focus of this research was to determine if an array of novel controlled release passive devices (CRPD) utilizing the spatial repellent, transfluthrin (TF), as the active ingredient could prevent entry of mosquitoes into military tents for up to 4 weeks. The TF-charged CRPDs were spaced along six strands of monofilament and hung across the tent entrance. Efficacy was evaluated with caged Aedes aegypti to indicate knockdown/mortality effects, and four species of free-flying mosquitoes, Ae. aegypti, Aedes taeniorhynchus, Anopheles quadrimaculatus and Culex quinquefasciatus, to indicate repellent effects. Bioassay cages containing Ae. aegypti were hung vertically at 0.5, 1.0 and 1.5 ​m above ground level at designated locations inside of the tents. Knockdown/mortality counts were made every 15 min for the first hour, then at 2, 4 and 24 h post-exposure. Free fliers were recaptured in BG traps operated from 4 to 24 h post-exposure. Knockdown/mortality was gradual until 4 h post-exposure. This increased to near 100% by 24 h in the treated tent but was < 2% in the control tent. There was a significant reduction in the recapture rates of all free-flying species in the treated tent compared with the control tent. Results indicate that TF-charged CRPDs can significantly reduce the numbers of mosquitoes entering military tents and that the four species were affected similarly by the TF. The needs for additional research are discussed.

HomeCirculation: Arrhythmia and ElectrophysiologyVol. 16, No. 12Effects of Intraluminal Content on Esophageal Lesion Formation During Radiofrequency Catheter Ablation: Preliminary Data No AccessResearch ArticleRequest AccessFull TextAboutView Full TextView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessResearch ArticleRequest AccessFull TextEffects of Intraluminal Content on Esophageal Lesion Formation During Radiofrequency Catheter Ablation: Preliminary Data Fabrizio Assis, Harikrishna Tandri, Rushil Shah, Christopher Batich, Parag Karmarkar, Akhilesh Gonuguntla, Michele Dill, Ekin C. Uzunoglu and John N. Catanzaro Fabrizio AssisFabrizio Assis https://orcid.org/0000-0003-2605-0447 Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD (F. A., P.K., A.G.). , Harikrishna TandriHarikrishna Tandri Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (H.T.). , Rushil ShahRushil Shah Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA (R.S.). , Christopher BatichChristopher Batich Department of Materials Science and Engineering, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville (C.B., M.D.). , Parag KarmarkarParag Karmarkar https://orcid.org/0000-0002-1147-5269 Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD (F. A., P.K., A.G.). , Akhilesh GonuguntlaAkhilesh Gonuguntla https://orcid.org/0000-0003-0873-2217 Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD (F. A., P.K., A.G.). , Michele DillMichele Dill Department of Materials Science and Engineering, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville (C.B., M.D.). , Ekin C. UzunogluEkin C. Uzunoglu Department of Medicine, Division of Cardiology, University of Florida Health Science Center, Jacksonville (E.C.U.). and John N. CatanzaroJohn N. Catanzaro Correspondence to: John N. Catanzaro, MD, MBA, Division of Cardiology, Department of Cardiovascular Sciences, Brody School of Medicine, East Carolina Heart Institute at East Carolina University Health Medical Center, 115 Heart Dr, Greenville, NC 27834. Email E-mail Address: [email protected] https://orcid.org/0000-0001-5671-1125 Department of Cardiovascular Sciences, East Carolina University, Greenville, NC (J.N.C.). Originally published16 Nov 2023https://doi.org/10.1161/CIRCEP.123.012404Circulation: Arrhythmia and Electrophysiology. 2023;16:672–674FootnotesThis article was sent to N.A. Mark Estes III, Guest Editor, for review by expert referees, editorial decision, and final disposition.For Sources of Funding and Disclosures, see page 673.Correspondence to: John N. Catanzaro, MD, MBA, Division of Cardiology, Department of Cardiovascular Sciences, Brody School of Medicine, East Carolina Heart Institute at East Carolina University Health Medical Center, 115 Heart Dr, Greenville, NC 27834. Email jncatanzaro@yahoo.comReferences1. Calkins H, Hindricks G, Cappato R, Kim YH, Saad EB, Aguinaga L, Akar JG, Badhwar V, Brugada J, Camm J, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation.Heart Rhythm. 2017; 14:e275–e444. doi: 10.1016/j.hrthm.2017.05.012CrossrefMedlineGoogle Scholar2. Leung LWM, Akhtar Z, Elbatran AI, Bajpai A, Li A, Norman M, Kaba R, Sohal M, Zuberi Z, Gallagher MM; on behalf of the IMPACT Study Group. Effect of esophageal cooling on ablation lesion formation in the left atrium: insights from ablation index data in the IMPACT trial and clinical outcomes.J Cardiovasc Electrophysiol. 2022; 33:2546–2557. doi: 10.1111/jce.15717CrossrefMedlineGoogle Scholar eLetters(0) eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate. Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page. Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetails December 2023Vol 16, Issue 12 Advertisement Article Information Metrics © 2023 American Heart Association, Inc.https://doi.org/10.1161/CIRCEP.123.012404PMID: 37970703 Originally publishedNovember 16, 2023 Keywordsatrial fibrillationesophageal fistulapulmonary veinsradiofrequency ablationthermal conductivityPDF download Advertisement Subjects Catheter Ablation and Implantable Cardioverter-Defibrillator

Presently, there is a need to develop effective and novel modes of control for mosquitoes, which remain a key driver of infectious disease transmission throughout the world. Control methods for these vectors have historically relied on a limited number of active ingredients (AIs) that have not experienced significant change in usage since the mid-20th century. The resulting development of widespread insecticide resistance has consequently increased the risk for future vector-borne disease outbreaks. Recently, metal nanoparticles have been explored for potential use in mosquito control due to their demonstrated toxicity against mosquitoes at all life stages. However, the majority of studies to date have focused on the larvicidal efficacy of metal nanoparticles with few studies examining their adulticidal potential. In this review, we analyze the current literature on green synthesized metal nanoparticles and their effect on adult mosquitoes.

Esophageal injury is a major concern during PVI procedures. Multiple esophageal protective strategies have been employed to minimize the risk with suboptimal results. Although the pathophysiology of lesion formation is recognized, the mechanism of thermal injury is multifactorial and still underexplored.

A microscopic study of microplankton in two coastal lagoons in the Florida Keys coincidently, and unexpectedly, revealed the widespread presence of high concentrations of polystyrene microplastic particles. The polystyrene particles were first observed in the second year of a 2-year study of phytoplankton communities, with peak densities in the spring/summer of 2019 at all ten sampling sites in the two lagoons. Polystyrene particle densities reached levels up to 76,000 L −1 . The particles ranged in size from 33 to 190 µm, similar to the size range of microplanktonic algae (20–200 µm). Over the period of peak polystyrene densities, average particle densities were similar to average densities of microplanktonic algae cells. The latter observation highlights the potential significance of the microplastic particles for the ecology of the pristine waters of the Florida Keys, if they persist.

Testing behavioral response to insecticidal volatiles requires modifications to the existing designs of olfactometers. To create a testing apparatus in which there is no chemical memory to confound tests, we detail the technical aspects of a new tool with design influences from other olfactometry tools. In addition, this new tool was used to evaluate a novel formulation of metofluthrin for use as an outdoor residual treatment. After sourcing materials to prioritize glass and metal construction, a modular wind tunnel was developed that hybridizes wind tunnel and olfactometer specifications. Volatile contaminants were removed by strong ultraviolet light within the chamber before and between trials. Repellent trials were conducted with an experimental formulation of metofluthrin and a commercial formulation of esfenvalerate, prallethrin, and piperonyl butoxide (Onslaught Fast Cap) against Aedes albopictus (Skuse). Toxicant vapors were delivered with attractants from a lure with behavioral responses scored 20 min post-exposure. Upwind attraction to the attractant lure and the Onslaught Fast Cap plus lure resulted in 90 and 75% capture, respectively. In contrast, metofluthrin vapors resulted in less than 10% attraction, while also causing repellency, disorientation, knockdown, and mortality effects. Our findings demonstrated that an inert modular wind tunnel was functional for mitigating toxic secondary exposures of spatial repellents amidst complex behavioral analysis in mosquitoes. The resulting observations with formulated metofluthrin positively reinforce the merit of transitioning metofluthrin into expanded roles in mosquito management.

The effect of pH changes on the chemical durability of dental glass–ceramic materials was evaluated using weight loss and ion release levels. The hypothesis that increased pH changes will exhibit greater corrosion was investigated. The ion concentration was analyzed using inductively coupled plasma atomic emission spectrometer (ICP). The surface compositions were investigated using X-ray photoelectron spectroscopy (XPS). The surface morphologies were examined using scanning electron microscopy (SEM). Dental glass–ceramics were tested in constant immersion, 3-day cycling, and 1-day cycling with pH 10, pH 2, and pH 7 for 3, 15, and 30 days. The 1-d cycling group demonstrated the highest levels of weight loss compared with 3-d cycling and constant immersion. For the ion release, Si4+ and Ca2+ had the highest rates of release in 1-d cycling, whereas the Al3+ release rate with constant pH 2 was highest. The alteration/passivation layer that was formed on the surface of disks possibly prevented further dissolution of pH 10 corroded disks. XPS analysis demonstrated different surface compositions of corroded disks in pH 10 and pH 2. Si4+, K+, Na+, Al3+, and Ca2+ were detected on the surface of corroded pH 10 disks, whereas a Si4+ and P5+-rich surface formed on corroded pH 2 disks. SEM results demonstrated rougher surfaces for corroded disks in cycling conditions and pH 2 constant immersion. In conclusion, increased pH changes significantly promote the corrosion of dental glass–ceramic materials.

• First complete research on dissolution activation of fluoroapatite glass-ceramic dental veneer. • Discussion of acid and alkaline corrosion behavior of fluoroapatite glass-ceramic dental veneer. • Characterization of crystalline phase and surface compositions in fluoroapatite glass-ceramic dental veneer.

The formation and characterization of positively surface charged TiN surfaces were investigated for improving dental implant survival. Surface nitrogen atoms of a traditional TiN implant were converted to a positive charge by a quaternization reaction which greatly increased the antibacterial efficiency. Ti, TiN, and quaternized TiN samples were incubated with human patient subgingival bacteria for 4 hours at 37°C in an anaerobic environment with an approximate 40% reduction in counts on the quaternized surface over traditional Ti and TiN. The samples were challenged with Streptococcus Mutans and fluorescent imaging confirmed significant reduction in the quaternized TiN over the traditional Ti and TiN. Contact angle measurement and X-Ray Photoelectron Spectroscopy (XPS) were utilized to confirm the surface chemistry changes. The XPS results found the charged quaternized nitrogen peak at 399.75 eV that is unique to the quaternized sample.

Conjugation of latent growth factors to superparamagnetic iron oxide nanoparticles (SPIONs) is potentially useful for magnetically triggered release of bioactive macromolecules. Thus, the goal of this work was to trigger the release of active Transforming Growth-Factor Beta (TGF-β) via magnetic hyperthermia by binding SPIONs to the latent form of TGF-β, since heat has been shown to induce release of TGF-β from the latent complex. Commercially available SPIONS with high specific absorption rates (SAR) were hydrolyzed in 70% ethanol to create surface carboxylic acid conjugation sites for carbodiimide chemistry. Fourier-Transform Infra-Red (FTIR) analysis verified the conversion of maleic anhydride to maleic acid. 1-Ethyl-2-(3-dimethyulaminopropyl) carbodiimide (EDC) and N-hydroxysulfosuccinimide (Sulfo-NHS) were used to bind to the open conjugation sites of the SPION in order to graft latent TGF-β onto the particles. The resulting conjugated particles were imaged with transmission electron microscopy (TEM), and the complexed particles were characterized by dynamic light scattering (DLS) and superconducting quantum interference device (SQUID) magnetometry. Enzyme-linked immunosorbent assay (ELISA) was used to assess the thermally triggered release of active TGF-β from the latent complex, demonstrating that conjugation did not interfere with release. Results showed that latent TGF-β was successfully conjugated to the iron oxide nanoparticles, and magnetically triggered release of active TGF-β was achieved.

Mosquitoes continue to be a major threat to global health, and the ability to reliably monitor, catch, and kill mosquitoes via passive traps is of great importance. Global, low-cost, and easy-to-use outdoor devices are needed to augment existing efforts in mosquito control that combat the spread of disease, such as Zika. Thus, we have developed a modular, portable, non-powered (passive), self-contained, and field-deployable device suitable for releasing volatiles with a wide range of applications such as attracting, repelling, and killing mosquitoes. This unique device relies on a novel nested wick and two-reservoir design that achieves a constant release of volatiles over several hundred hours. Devices loaded with one of either two compounds, geraniol or 1-methylpiperazine (MP), were tested in a controlled environment (32 °C and 70% relative humidity), and both compounds achieved a constant release from our devices at a rate of 2.4 mg/h and 47 mg/h, respectively. The liquid payload can be volatile attractants or repellants as well as mosquitocide-containing feeding solutions for capture and surveillance. This low-cost device can be utilized for both civilian and military mosquito control purposes, but it will be particularly important for protecting those in economically repressed environments, such as sub-Saharan Africa and Central and South America.

Understanding short-range cues (e.g., host odorants, heat, moisture) of host-seeking female Aedes aegypti L. is very important for attempts to reduce mosquito bites, to complement current control strategies, and to develop potential spatial repellents. We investigated behavior under semi-field conditions utilizing a new portable uni-port taxis box with a caged chicken host. The combined influences of airflow regimes (0, 1.5, 3, 5, and 6 m/s), distance from host odor (10, 50, 100 cm), host-odor confinement (partial confinement/unconfined), and foraging periodicity (day/evening) were studied. Statistical regression analysis was used to delineate the significant factors that predict upwind flight behavior and short-range source location. Almost 15% of host-seeking Ae. aegypti were activated by an unconfined chicken odor in still air. This was double the number of attracted mosquitoes to confined host odor. The maximum behavioral response was reported with airflow of 5 m/s during daytime (76.7% ± 2.85) at a distance of 10 (70.7% ± 2.47) and 50 cm (56.7% ± 8.88). However, airflow of 6 m/s activated host-seeking orientation during evening assays. The host-seeking response between indoor and outdoor experiments was not significantly different and demonstrated the reliability of the portable taxis box in evaluating mosquito short-range behavioral response toward hosts.

A rapid thermal desorption-gas chromatography-electron ionization-mass spectrometry (TD-GC-El-MS) method far airborne transfluthrin detection is studied. Active air sampling of 9 Lover 1 hat 23 degrees C through a Tenak (R)-loaded tube resulted in efficient capture of airborne transfluthrin. Subsequent thermal desorption was employed to achieve an LOD of 2.6 ppq(v) (parts per quadrillion by volume). A minimum primary desorption temperature of 300 degrees C is necessary for optimal recovery of sample from the Tenax (R) adsorbent. The matrix effects of indoor air lead to an error of 10.9% and 10.5% recovery of sample (10 pg and 100 pg loaded tubes, respectively). The linear range was 74-74,000 ppq(v) with a correlation coefficient of 0.9981. Active air sampling of a novel passive release device revealed a similar to 150 pg/L airborne concentration gradient over 1 m. providing spatial characterization of the device's performance. This efficient method allows for the remote collection of samples and rapid analysis of airborne transfluthrin from industrial applications, optimization studies of commercial products as well as domestic/household monitoring. (C) 2018 The Author(s). Published by Elsevier B.V.

PURPOSE:Multiuse eye drops must maintain sterility and typically accomplish this by added preservatives. However, preservatives often cause harmful side effects. A gauze barrier dressing ("BIOGUARD®") recently cleared by the FDA has an immobilized poly diallyldimethylammonium chloride (p-DADMAC) coating and is an effective antimicrobial with minimal compound release into solution. To implement use of this dressing as a replacement for preservatives in multidose eye drop bottles, its ability to maintain sterility without interacting with the active ingredient (AI) of the ophthalmic medication was tested.METHODS:To determine immobilized p-DADMAC's microbicidal efficacy, it was added to eye drop bottles, then contaminated with Staphylococcus aureus (SA113) bacteria. To assess interference with AI in eye drops, high performance liquid chromatography was used to determine whether the AIs timolol and dorzolamide were affected after exposure to p-DADMAC. To further investigate effects on AI, the microbicidal activity of Vigamox® (moxifoxacin) was assessed after p-DADMAC gauze exposure.RESULTS:S. aureus bacteria were eliminated by p-DADMAC-treated gauze for all samples. The concentrations of both timolol and dorzolamide increased after exposure to p-DADMAC-treated gauze, but spectrometric analysis showed that this did not occur when the p-DADMAC-coated material was presoaked in deionized water. The microbicidial activity of moxifloxacin was unaffected by exposure to p-DADMAC-treated gauze.CONCLUSIONS:Due to its lack of effect on eye drop AI and its microbicidal efficacy, p-DADMAC treatment would make an excellent candidate for replacing preservatives in eye drops.

OBJECTIVETo determine the ability of a polyacrylic acid-silicone radiolucent self-retaining gradual occlusion device (PAS-OD) to attenuate congenital extrahepatic portosystemic shunts (EHPSS) in dogs.STUDY DESIGNProspective clinical trial.ANIMALSSix client-owned dogs with single, congenital EHPSS.METHODSSerum bile acids (SBA), abdominal ultrasonography, and computed tomographic angiography (CTA) were performed preoperatively and at 4 and 8 weeks postoperatively. Each dog was treated for EHPSS by placement of a PAS-OD.RESULTSPAS-OD were placed without complication an average of 4.3 seconds (range, 3-7) after isolation of the shunt. Median surgical time was 38.5 minutes (range, 28-84) including concurrent procedures. All dogs recovered from surgery without complications. SBA were normal in 5 of 6 dogs at 4 and 8 weeks after surgery. The shunt was completely attenuated in 2 of 6 dogs at 4 weeks and in 4 of 6 dogs at 8 weeks, without evidence of acquired shunt formation in any dog. The size and velocity of the portal vasculature were improved in 5 of 6 dogs according to 8-week postoperative CTA and ultrasonography results, respectively. The remaining dog had a persistently decreased portal vasculature size but a normal velocity according to 8-week postoperative CTA and ultrasound results, respectively.CONCLUSIONThe PAS-OD led to complete attenuation in 4 of 6 dogs and partial attenuation with mild residual flow of 2 EHPSS over an 8-week period in dogs.CLINICAL SIGNIFICANCEThe PAS-OD is a new option for gradual occlusion of congenital EHPSS over 8 weeks.

OBJECTIVE To evaluate the closure rate and completeness of closure for a silicone-polyacrylic acid gradual venous occlusion device placed around an intra-abdominal vein to simulate gradual occlusion of an extrahepatic portosystemic shunt. ANIMALS 3 purpose-bred cats and 2 purpose-bred dogs. PROCEDURES The device was surgically placed around an external (cats) or internal (dogs) iliac vein. Computed tomographic angiography was performed at the time of surgery and 2, 4, and 6 weeks after surgery. Ultrasonographic examinations of blood flow through the vein within the device were performed at the time of surgery and at weekly intervals thereafter. Dogs were euthanized 6 weeks after surgery, and the external iliac veins were harvested for histologic examination. RESULTS The prototype gradual venous occlusion device was successfully placed in all animals, and all animals recovered without complications following the placement procedure. The vessel was completely occluded in 2 cats by 6 weeks after surgery, as determined on the basis of results of CT and ultrasonography; there was incomplete occlusion with a luminal diameter of 1.5 mm in the other cat by 6 weeks after surgery. The vessel was completely occluded in both dogs by 6 weeks after surgery. Histologic examination of the external iliac veins obtained from the dogs revealed minimal inflammation of the vessel wall and no thrombus formation. CONCLUSIONS AND CLINICAL RELEVANCE The prototype device induced gradual attenuation of an intra-abdominal vessel over a 6-week period. This device may provide another option for gradual occlusion of extrahepatic portosystemic shunts.

OBJECTIVE:To develop a device intended for gradual venous occlusion over 4 to 6 weeks.SAMPLE:Silicone tubing filled with various inorganic salt and polyacrylic acid (PAA) formulations and mounted within a polypropylene or polyether ether ketone (PEEK) outer ring.PROCEDURES:15 polypropylene prototype rings were initially filled with 1 of 5 formulations and placed in PBSS. In a second test, 10 polypropylene and 7 PEEK prototype rings were filled with 1 formulation and placed in PBSS. In a third test, 2 formulations were loaded into 6 PEEK rings each, placed in physiologic solution, and incubated. In all tests, ring luminal diameter, outer diameter, and luminal area were measured over 6 weeks.RESULTS:In the first test, 2 formulations had the greatest changes in luminal area and diameter, and 1 of those had a greater linear swell rate than the other had. In the second test, 6 of 7 PEEK rings and 6 of 10 polypropylene rings closed to a luminal diamater < 1 mm within 6 weeks. Polypropylene rings had a greater increase in outer diameter than did PEEK rings between 4.5 and 6 weeks. In the third test, 11 of 12 PEEK rings gradually closed to a luminal diameter < 1 mm within 6 weeks.CONCLUSIONS AND CLINICAL RELEVANCE:A PAA and inorganic salt formulation in a prototype silicone and polymer ring resulted in gradual occlusion over 4 to 6 weeks in vitro. Prototype PEEK rings provided more reliable closure than did polypropylene rings.