106 research outputs found
Disruption of outdoor activities caused by wildfire smoke shapes circulation of respiratory pathogens
No full textAs climate change accelerates, the frequency and severity of extreme weather events, such as wildfires, are increasing, with profound impacts on human health. While much attention has been paid to the direct health consequences of these events, such as chronic diseases from poor air quality, less is known about how behavioral shifts induced by such events can influence the transmission of infectious diseases. This study investigates how wildfire-induced changes in human behavior during the U.S. West Coast wildfires of 2020 may affect the spread of airborne diseases. Using a mobility data-driven indoor activity index, we find that the wildfire-induced deterioration of air quality led to a substantial increase in indoor activities, fostering conditions conducive to airborne disease transmission. Specifically, counties in Oregon and Washington experienced an average 10.8% and 14.3% increase in indoor activity, respectively, during the wildfire events, with major cities like Portland and Seattle experiencing increases of 11% and 16%, respectively. We quantify these behavioral changes and integrate them into an SIR epidemic model to characterize the increased indoor activity and disease dynamics. The model predicts the greatest impact on diseases with shorter generation times, such as RSV and influenza. Our results show that even a modest increase in indoor mask-wearing (as low as 10%) could significantly reduce the risk of disease spread in these settings, with higher compliance needed for more substantial reductions. As wildfires and other climate-related events become more frequent, integrating behavioral responses into public health policies will be crucial to mitigate the compounded risks of climate change and its secondary health impacts.[Author summary] The effects of climate change on human health are becoming more evident, but we often overlook one crucial factor: how extreme weather events influence our behaviors and, in turn, the spread of infectious diseases. In this study, we explore the role of wildfire-induced behavioral changes on the transmission of airborne diseases, focusing on the U.S. West Coast wildfires of September 2020. Our findings show that wildfires led to a dramatic increase in indoor activities, creating the ideal conditions for respiratory diseases such as influenza to spread. But—by incorporating simple measures like indoor mask-wearing, we can reduce this risk. This research underscores the importance of considering human behavior responses when tackling health risks associated with climate change. As we face more frequent extreme events, public health strategies must evolve to address not just the environmental impact, but also the ways we adapt, react to the emergency. By understanding and planning for this behavioral response, we can better protect public health in a warming world.Research reported in this publication was supported by the Fritz-Family fellowship program to SB and GP.Peer reviewe
Surgical treatments for patients with recurrent bile duct stones and Oddis sphincter laxity
No full textDendrimer-based drug delivery systems: history, challenges, and latest developments
No full textSince the first dendrimer was reported in 1978 by Fritz Vögtle, dendrimer research has grown exponentially, from synthesis to application in the past four decades. The distinct structure characteristics of dendrimers include nanoscopic size, multi-functionalized surface, high branching, cavernous interior, and so on, making dendrimers themselves ideal drug delivery vehicles. This mini review article provides a brief overview of dendrimer’s history and properties and the latest developments of dendrimers as drug delivery systems. This review focuses on the latest progress in the applications of dendrimers as drug and gene carriers, including 1) active drug release strategies to dissociate drug/gene from dendrimer in response to stimuli; 2) size-adaptive and charge reversal dendrimer delivery systems that can better take advantage of the size and surface properties of dendrimer; 3) bulk and micro/nano dendrimer gel delivery systems. The recent advances in dendrimer formulations may lead to the generation of new drug and gene products and enable the development of novel combination therapies
Ecofriendly Method to Dissolve Chitosan in Plain Water
No full textChitosan is an important and abundant natural-based polymer, and it has broad applications. However, dissolving chitosan in plain water is a challenge, which mostly limits the biomedical applications of chitosan materials. Herein, we report an ecofriendly dissolution method to obtain a plain water-based chitosan solution for the first time. In this method, dissolving chitosan in ionic liquid followed by overnight freezing at -20 °C and subsequent solvent exchange with plain water at room temperature results in a stable chitosan dispersion in water with nanosize, namely water-based, chitosan pseudosolution. The overall process is ecofriendly. This new method augments the quality and processability of chitosan solutions used in manufacturing and bioprocessing and promotes the biomedical applications of chitosan-based products
Dendrimer and dendrimer gel‐derived drug delivery systems: Breaking bottlenecks of topical administration of glaucoma medications
No full textDue to high structural flexibility, multidrug carrying capability, and tunable size, dendrimers have been used as suitable carriers for ophthalmic drug delivery. Drug molecules can be either encapsulated or chemically coupled to dendrimers. the nanoscopic size, spheroidal shape, and cationic surface of Poly amidoamine (PAMAM) dendrimers promote their interaction with the cornea and result in prolonged precorneal retention. Dendrimers could be further cross-linked to produce three-dimensional hydrogel networks or dendrimer hydrogels (DH). the properties of the DH can be readily adjusted to maintain both fluidity and adhesiveness, making them suitable for developing topical ocular drug formulations. Micro-/nano- sized DHs, that is, dendrimer micro-/nano- gels, have unique properties such as ease of administration, large specific surface area for adhesion, and drug targeting functionalities, making them attractive for ophthalmic drug delivery. This perspective reports advances in PAMAM dendrimer-based drug delivery systems including drug conjugates and micro- and nano- gels to enhance and sustain the delivery of multiple anti-glaucoma drugs, Dendrimer and dendrimer gel-derived drug delivery systems hold great potential as multifunctional topical drug delivery systems for the eye
A Hybrid Dendrimer Hydrogel as Bone Tuberculosis Defect Scaffold for Regeneration and Chemotherapy
No full textStatement of Purpose: The effective treatment of serious bone tuberculosis is suggested to combine chemotherapy and bone regeneration.1 A multicomponent hybrid dendrimer hydrogel (HDH) is developed by integrating dendrimer, dendrimer/silver nanoparticle (Ag NP) complex, mesoporous silica nanoparticle (MSN) into a well-defined gelation system based on Aza-Michael addition cross-linking strategy.2 The introducing of MSN and Ag NP enhanced the mechanical properties of HDH significantly compared to plain dendrimer hydrogel, which makes the HDH ideal to be used as bone regeneration scaffold. The hybrid hydrogel provides multiple sites for drug loading to realize drug release kinetics at different time scale. In this study, a water-soluble isoniazid is loaded to the cross-linking network of the hybrid dendrimer hydrogel, whereas a hydrophobic rifampicin is encapsulated into the mesoporous of MSN
Microstructure and Wear Resistance of Si-TC4 Composite Coatings by High-Speed Wire-Powder Laser Cladding
No full textThe hardness and wear resistance of the surface of TC4 titanium alloy, which is widely used in aerospace and other fields, need to be improved urgently. Considering the economy, environmental friendliness, and high efficiency, Si-reinforced Ti-based composite coatings were deposited on the TC4 surface by the high-speed wire-powder laser cladding method, which combines the paraxial feeding of TC4 wires with the coaxial feeding of Si powders. The microstructures and wear resistance of the coatings were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), Vickers hardness tester, and friction and wear tester. The results indicate that the primary composition of the coating consisted of α-Ti and Ti5Si3. The microstructure of the coating underwent a notable transformation process from dendritic to petal, bar, and block shapes as the powder feeding speed increased. The hardness of the composite coatings increased with the increasing Si powder feeding rate, and the average hardness of the composite coating was 909HV0.2 when the feeding rate reached 13.53 g/min. The enhancement of the microhardness of the coatings can be attributed primarily to the reinforcing effect of the second phase generated by Ti5Si3 in various forms within the coatings. As the powder feeding speed increased, the wear resistance initially improved before deteriorating. The optimal wear resistance of the coating was achieved at a powder feeding rate of 6.88 g/min (wear loss of 2.55 mg and friction coefficient of 0.12). The main wear mechanism for coatings was abrasive wear
Drug-Loaded Chitosan Film Prepared via Facile Solution Casting and Air-Drying of Plain Water-Based Chitosan Solution for Ocular Drug Delivery
No full textChitosan is a nature-based polymer with low toxicity, excellent biocompatibility and biodegradability. However, the intractable solubility of chitosan in water and most conventional solvents hampers its biomedical applications. Following the dissolution method for dissolving chitosan in plain water developed by us, chitosan was dissolved in ionic liquid followed by overnight freezing at −20 °C and subsequent solvent exchange with plain water at room temperature. In this study, we fabricated a drug-carrying chitosan film via solution casting and air-drying by using the plain water-based chitosan solution. Specifically, brimonidine tartrate (BT), an antiglaucoma drug, was dissolved in the plain-water based solution and used to prepare BT-loaded chitosan film, i.e., chitosan-BT film. The resulting film is transparent, structurally stable, and mucoadhesive. Micro-sized antiglaucoma BT drug crystals form and are well dispersed in the chitosan film. The chitosan-BT film enables BT to have a high corneal permeability with fast drug release kinetics for potential ocular drug delivery
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