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Passive daytime radiative cooling (PDRC) presents a promising avenue for efficient thermal management without relying on electrical power. In this study, the potential of integrating Hollow Yttrium-Oxide Spheres (HYSs) within a Polydimethylsiloxane (PDMS) matrix to enhance PDRC is investigated. Through a combination of experimental characterization and computational analysis, the optical properties and radiative cooling performance of PDMS films embedded with HYSs are evaluated. These results demonstrate that HYSs significantly improve both solar reflectivity and long-wave infrared (LWIR) emissivity of the PDMS matrix. Finite-Difference Time-Domain (FDTD) simulations confirm the scattering efficiency of HYSs across various wavelength ranges, highlighting their effectiveness as additives for enhancing the radiative properties of passive cooling materials. Experimental validation reveals enhanced reflectivity and emissivity of PDMS films with embedded HYSs, resulting in superior cooling performance compared to non-HYS counterparts. Overall, this study underscores the potential of HYS-infused PDMS films as a promising solution for passive radiative cooling, with broad applicability in diverse domains requiring efficient thermal management solutions. Additionally, these research insights pave the way for establishing an AI database for passive radiative cooling research, offering new avenues for further exploration and application in this field.

In this work, we propose an approach for obtaining polydimethylsiloxanes of various structures, both linear and branched, by a ring-opening polymerization (ROP) of hexamethylcyclotrisiloxane initiated by silanols in liquid ammonia. In this case, ammonia acts both as a solvent and as a catalyst. Such hydroxy-containing compounds as Ph3SiOH, Ph2Si(OH)2, PhSi(OH)3 and cis-[PhSi(O)OH]4 are used as initiators. [ABSTRACT FROM AUTHOR]

CsCu2I3 CsCu2I3 lead‐free nanocrystals (NCs) have recently garnered significant interest for their outstanding optical and scintillation characteristics, particularly for X‐ray imaging applications. In this study, CsCu2I3 NCs are mixed with polydimethylsiloxane (PDMS) resin in the form of a pellet to protect against environmental factors such as moisture. The resulting sample exhibits a light yield of up to 2 ph keV−1 and an excellent energy resolution of 13% for γ‐ray excitation at 662 keV at room temperature. Additionally, the CsCu2I3 NCs–PDMS resin shows no afterglow and has a negligible trap density. Herein, high stability at low irradiation intensities and reasonable stability at higher intensities are demonstrated. Moreover, the sample features a fast component scintillation decay times of 3.55 ns, which is slightly faster than that of (BZA)2PbBr4. This outcome possesses promising combination in designing lightweight and flexible hybrid PDMS‐based hybrid materials scintillators. These scintillation properties of CsCu2I3 NCs–PDMS can be a promising candidate for affordable and flexible screens for X‐ and γ‐ray photon‐counting computed tomography. [ABSTRACT FROM AUTHOR]

Emulating very soft tissues with synthetic materials is important for clinical prosthetists who want to improve compliance in maxillofacial and breast prosthesis. It is equally important for theatrical prosthetists wanting to model bariatric conditions and soft organs for surgical or palpation training. Polydimethylsiloxane (PDMS) gels, which are often used in medical model construction, are stiff and highly elastic compared to the friable soft tissues found in the body. Silicone oil is known to soften PDMS gels, but it is not known precisely how oil dispersal affects these gels and what proportion of oil is needed to simulate very soft tissue membranes like adipose tissue. In this work, internationally agreed test standards were used to mechanically characterize a range of PDMS gel membranes saturated with different amounts of silicone oil to determine whether materials with behavioral similarities to adipose tissue could be created. Mechanical properties like hardness, elasticity, strength, viscoelastic behavior and cure-time are presented in this study, which are all key factors required by the creators of such membranes. Results were compared to identical tests on porcine fat and data in the literature for porcine and human fat. The data revealed a strong correlation between increases in oil content and decreases in membrane hardness, strength and elastic modulus. It was also found that increases in oil content caused proportional increases in cure time, while membranes with equal amounts of oil and gel were best at mimicking characteristics of human and porcine fat, like hardness and elasticity. [ABSTRACT FROM AUTHOR]

Isaac Newton once contemplated the fall of an apple, setting in motion a revolution in the understanding of gravity. In a similar spirit of curiosity and inquiry, here a journey is embarked upon to explore the intricate world of viscoelastic damping for polydimethylsiloxanes (PDMS). Inspired by the notion that even the simplest of phenomena can yield profound insights, a novel approach to study damping in silicone elastomers through a simple ball drop test is introduced. This novel solution allowes for precise measuring and analyzing the material's damping characteristics under various conditions. By carefully controlling the release and monitoring, the response of the falling ball by simple video tracking, valuable insights into the key viscoelastic properties of silicone blends are extracted, including rebound resilience, Young's modulus, and complex modulus. Through the analysis of trajectory data generated during the sphere's interaction with the silicone damper, dynamic and static material parameters are determined. Remarkably, these outcomes closely align with results obtained from cost‐intensive and high‐maintenance industrial measurement setups such as dynamic thermomechanical analysis (DTMA) or tensile testing. This approach not only simplifies the complexity of the system but also offers a cost‐effective and efficient means of gaining essential knowledge in material science. [ABSTRACT FROM AUTHOR]

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The development of wearable bioelectronic systems is a promising approach for optimal delivery of therapeutic treatments. These systems can provide continuous delivery of ions, charged biomolecules, and an electric field for various medical applications. However, rapid prototyping of wearable bioelectronic systems for controlled delivery of specific treatments with a scalable fabrication process is challenging. We present a wearable bioelectronic system comprised of a polydimethylsiloxane (PDMS) device cast in customizable 3D printed molds and a printed circuit board (PCB), which employs commercially available engineering components and tools throughout design and fabrication. The system, featuring solution-filled reservoirs, embedded electrodes, and hydrogel-filled capillary tubing, is assembled modularly. The PDMS and PCB both contain matching through-holes designed to hold metallic contact posts coated with silver epoxy, allowing for mechanical and electrical integration. This assembly scheme allows us to interchange subsystem components, such as various PCB designs and reservoir solutions. We present three PCB designs: a wired version and two battery-powered versions with and without onboard memory. The wired design uses an external voltage controller for device actuation. The battery-powered PCB design uses a microcontroller unit to enable pre-programmed applied voltages and deep sleep mode to prolong battery run time. Finally, the battery-powered PCB with onboard memory is developed to record delivered currents, which enables us to verify treatment dose delivered. To demonstrate the functionality of the platform, the devices are used to deliver H[Formula: see text] in vivo using mouse models and fluoxetine ex vivo using a simulated wound environment. Immunohistochemistry staining shows an improvement of 35.86% in the M1/M2 ratio of H[Formula: see text]-treated wounds compared with control wounds, indicating the potential of the platform to improve wound healing.

In this article, we present an analysis of the properties of polyaddition poly(dimethylsiloxanes) (PDMS) and their potential applications after modification. The focus is on understanding how different fillers and mixing speeds affect the mechanical and electrical properties of PDMS, as well as the benefits and challenges associated with these modifications. Additionally, the prospects for future development of PDMS-based technologies, which could bring significant innovations in various industrial fields, are discussed. [ABSTRACT FROM AUTHOR]

The problem of plastic waste in the environment calls for the development of new polymeric materials designed specifically for easy recycling at the end of their life cycle. Herein, a green polymer system comprising a series of necklace‐shaped polydimethylsiloxanes bearing anthracene dimer units is developed. The polymers have low environmental impact and are easily recycled. Further, their flexibility and glass transition temperatures are easy to control. These necklace‐shaped inorganic polymers are synthesized by photopolymerizing (dimerizing) anthracene‐terminated oligo‐dimethylsiloxane monomers. A key achievement of the present work is the successful chemical recovery of the monomers from the polymers through thermal depolymerization, enabling monomer–polymer recycling. By applying equilibrium polymerization with base catalysts, monomers with a controlled distributed chain length are synthesized from monomers with a constant chain length. The necklace‐shaped polymers synthesized from these randomized monomers have amorphous structures and readily form transparent films. It is possible to modulate the thermal and mechanical properties of the polymers by controlling the average chain length of the polydimethylsiloxane between the anthracene dimers. This investigation presents a method for the synthesis and cyclic utilization of polymer materials with a wide range of applications, including plastics and elastomers. [ABSTRACT FROM AUTHOR]

Objectives: In vivo, the principal function of mechanosensitive odontoblasts is to synthesize and secrete the matrix which then calcifies and forms reactive dentin after exposure to appropriate stimuli. This study aims to develop the influence of mechanical factors on dentinogenesis based on odontoblasts, which contribute to reparative dentin formation. Methods: We fabricated polydimethylsiloxane with different stiffnesses and seeded 17IIA11 odontoblast‐like cells on the substrates in different stiffnesses. Cell morphology was detected by scanning electron microscope, and the mineralization phenotype was detected by alkaline phosphatase staining and alizarin red staining, while expression levels of dentinogenesis‐related genes (including Runx2, Osx, and Alp) were assayed by qPCR. To explore mechanism, protein distribution and expression levels were detected by immunofluorescent staining, Western blotting, and immunoprecipitation. Results: In our results, during dentinogenesis, 17IIA11 odontoblast‐like cells appeared better extension on stiffer substrates. The binding between LAMB1 and FAK contributed to converting mechanical stimuli into biochemical signaling, thereby controlling mitogen‐activated protein kinase kinase 1/2 activity in stiffness‐driven dentinogenesis. Conclusion: The present study suggests odontoblast behaviors can be directly regulated by mechanical factors at cell–material interfaces, which offers fundamental mechanism in remodeling cell microenvironment, thereby contributing to physiological phenomena explanation and tissue engineering progress. [ABSTRACT FROM AUTHOR]

Simple Summary: Neuroblastoma (NB), a prevalent childhood cancer, presents challenges in treatment due to its cellular diversity and the presence of tumor-derived endothelial cells (TECs) associated with chemoresistance. We lack specific biomarkers for TECs, hindering effective therapies. We developed a stiffness-based in vitro platform simulating arterial and venous conditions to address this gap. Notably, adrenergic NB cells transdifferentiated into TECs where there was an arterial-like stiffness, while mesenchymal cells did not. This platform facilitated the identification of Globotriaosylceramide (GB3) as a novel TEC biomarker. Moreover, we harnessed Shiga toxin-functionalized nanoparticles for the specific targeting of GB3-positive cells, showing promise for future therapeutic strategies. Our study provides insights into NB heterogeneity, offers a predictive tool for assessing aggressiveness, and introduces potential targets for precision therapies. Neuroblastoma (NB) is a childhood cancer in sympathetic nervous system cells. NB exhibits cellular heterogeneity, with adrenergic and mesenchymal states displaying distinct tumorigenic potentials. NB is highly vascularized, and blood vessels can form through various mechanisms, including endothelial transdifferentiation, leading to the development of tumor-derived endothelial cells (TECs) associated with chemoresistance. We lack specific biomarkers for TECs. Therefore, identifying new TEC biomarkers is vital for effective NB therapies. A stiffness-based platform simulating human arterial and venous stiffness was developed to study NB TECs in vitro. Adrenergic cells cultured on arterial-like stiffness transdifferentiated into TECs, while mesenchymal state cells did not. The TECs derived from adrenergic cells served as a model to explore new biomarkers, with a particular focus on GB3, a glycosphingolipid receptor implicated in angiogenesis, metastasis, and drug resistance. Notably, the TECs unequivocally expressed GB3, validating its novelty as a marker. To explore targeted therapeutic interventions, nanoparticles functionalized with the non-toxic subunit B of the Shiga toxin were generated, because they demonstrated a robust affinity for GB3-positive cells. Our results demonstrate the value of the stiffness-based platform as a predictive tool for assessing NB aggressiveness, the discovery of new biomarkers, and the evaluation of the effectiveness of targeted therapeutic strategies. [ABSTRACT FROM AUTHOR]

Introduction: Head lice (Pediculus capitis) infestation is considered an important hygienic problem in developing countries. The aim of study was to compare 1% permethrin shampoo and 4% dimethicone lotion effects for treatment of infected head lice students in primary girl schools in Gotvand County, Khuzestan province. Methods: The studied population was first- to sixth-grade students in elementary schools. Positive cases with head lice after identification (304 persons) were randomly divided into two treatment groups. Permethrin shampoo and dimethicone lotion were allocated for the first and the second groups, respectively. The drug therapeutic effects were studied after 7, 14 and 21 days after treatment. Data were analyzed by Chi-square test using SPSS software. This study was approved by the Ethics Committee of Hamadan University of Medical Sciences (Code: IR.UMSHA.REC.1399.778). Results: In total, 304 students participated in the study. The age of students ranged between 7 and 12 years which 47.7% of them were between 7 and 8 years. Also 60.9 and 39.1% of them were in urban and rural schools, respectively. The drug effectiveness were 46.1, 69.5 and 100, and 77.6, 85.3 and 100% for permethrin and dimethicone in the first, second and third intervals after treatment, respectively. There was a significant difference between the effect of drugs in the first interval (P = 0.00) after treatment but there was not a significant difference between the second (P = 0.084) and the third (P = 0.43) intervals after treatment. Conclusions: It is recommended the use of dimethicone lotion and permethrin shampoo as the first and second option, respectively in eliminating the head lice infestation in primary girl schools. [ABSTRACT FROM AUTHOR]

In this research, a series of silicone foam/polytitanosiloxane composites (SF-pTS) were fabricated with hydroxy-, vinyl-, hydrogen-containing polydimethylsiloxanes, and polytitanosiloxane filler in the presence of a platinum catalyst under ambient conditions. The effect of the amount of polytitasiloxane on the micromorphology and flame retardancy of silicone foam was studied, and a relative flame retardancy mechanism was proposed. It could be found that the polytitanosiloxane exhibited a good dispersion level in the silicone foam, thus improving the flame retardancy of the composite. When the content of polytitanosiloxane is 9 wt%, the limiting oxygen index and UL-94 grade of the SF-pTS9 composite are increased to 29.2% and FV-0, respectively. Cone experiment results suggested that the SF-pTS9 possessed relative balanced PHRR (148.9 kW/m2), THR (58.5 MJ/m2), TSP (0.6 m2), and mass residue (83.9%) among the prepared silicone foam materials. This work provides a new avenue to fabricate a silicone foam composite with enhanced flame retardancy. [ABSTRACT FROM AUTHOR]

The main factors hindering the applicability of superhydrophobic coatings are their complex preparation methods, high cost, and poor mechanical stability. To address some of these issues, coatings using polydimethylsiloxanes (PDMS) with good mechanical stability having self-healing properties were prepared by combining the sodium chloride particles template with flame treatment technology. This coating demonstrated good superhydrophobicity due to the micro/nanostructure on its surface having a maximum water contact angle of 163° and a water sliding angle of less than 2°. Moreover, it exhibited good mechanical stability, which was examined by tape peeling and sandpaper abrasion tests. It was also observed that the damaged PDMS coating recovered its superhydrophobicity after flame treatment due to the partial decomposition of the polymers. We have shown that high-quality PDMS superhydrophobic coating can be prepared with a low-cost and simple method, which has great applicability potential in frost resistance and self-cleaning.This title is mismatch with jobsheet title. Please check if it is correct or not and proceed furtherThis title is correct. [ABSTRACT FROM AUTHOR]

Introduction and hypothesisThis study aimed to report 3-year completed follow-up of the safety and efficacy of Macroplastique® (MPQ) in women with stress urinary incontinence (SUI) due to intrinsic sphincter deficiency (ISD).MethodsThis is a retrospective analysis of all women who completed 3-year follow-up post-MPQ injection(s) at ten medical centers. We used the ROSE registry data report of Macroplastique® [Macroplastique® Real-time Observation of Safety and Effectiveness (ROSE) registry P040050/PAS001 on 2017]. Subjective incontinence outcome and adverse effects were assessed.ResultsThe study included all patients (n = 70) who completed 3-year follow-up after the last MPQ injection. Twenty-four of 70 (34%) patients had two injections; 21/70 (30%) patients reported Stamey grade 0 and 28/70 (40%) reported Stamey grade 1. The overall patient satisfaction was 68% who completed 3-year follow-up. The composite success rate (I-QoL, PGI-S, and Stamey grade improvement) was 51.4%. No serious adverse events (AE) were reported within the completed 3-year follow-up.ConclusionsMPQ was found to be safe and efficacious for the treatment of SUI secondary to ISD in women. The overall high satisfaction rate was sustained from baseline to 3 years post-injection. Most complications were minor and transient without sequelae.

The relative positioning of cells is a key feature of the microenvironment that organizes cell-cell interactions. To study the interactions between cells of the same or different type, micropatterning techniques have proved useful. DNA Programmed Assembly of Cells (DPAC) is a micropatterning technique that targets the adhesion of cells to a substrate or other cells using DNA hybridization. The most basic operations in DPAC begin with decorating cell membranes with lipid-modified oligonucleotides, then flowing them over a substrate that has been patterned with complementary DNA sequences. Cells adhere selectively to the substrate only where they find a complementary DNA sequence. Non-adherent cells are washed away, revealing a pattern of adherent cells. Additional operations include further rounds of cell-substrate or cell-cell adhesion, as well as transferring the patterns formed by DPAC to an embedding hydrogel for long-term culture. Previously, methods for patterning oligonucleotides on surfaces and decorating cells with DNA sequences required specialized equipment and custom DNA synthesis, respectively. We report an updated version of the protocol, utilizing an inexpensive benchtop photolithography setup and commercially available cholesterol modified oligonucleotides (CMOs) deployed using a modular format. CMO-labeled cells adhere with high efficiency to DNA-patterned substrates. This approach can be used to pattern multiple cell types at once with high precision and to create arrays of microtissues embedded within an extracellular matrix. Advantages of this method include its high resolution, ability to embed cells into a three-dimensional microenvironment without disrupting the micropattern, and flexibility in patterning any cell type.

Polydimethylsiloxane (PDMS) organogel sponges were prepared and studied in order to understand the role of pore size in an elastomeric network on the ability to uptake and release organic solvents. PDMS organogel sponges have been produced according to sugar leaching techniques by adding two sugar templates of different forms and grain sizes (a sugar cube template and a powdered sugar template), in order to obtain materials differing in porosity, pore size distribution, and solvent absorption and liquid retention capability. These materials were compared to PDMS organogel slabs that do not contain pores. The sponges were characterized by Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and compared with PDMS slabs that do not contain pores. Scanning electron microscopy (SEM) provided information about their morphology. X-ray micro-tomography (XMT) allowed us to ascertain how the form of the sugar templating agent influences the porosity of the systems: when templated with sugar cubes, the porosity was 77% and the mean size of the pores was ca. 300 μm; when templated with powdered sugar, the porosity decreased to ca. 10% and the mean pore size was reduced to ca. 75 μm. These materials, porous organic polymers (POPs), can absorb many solvents in different proportions as a function of their polarity. Absorption capacity, as measured by swelling with eight solvents covering a wide range of polarities, was investigated. Rheology data established that solvent absorption did not have an appreciable impact on the gel-like properties of the sponges, suggesting their potential for applications in cultural heritage conservation. Application tests were conducted on the surfaces of two different lab mock-ups that simulate real painted works of art. They demonstrated further that PDMS sponges are a potential innovative support for controlled and selective cleaning of works of art surfaces. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxanes (PDMS) foam as one of next-generation polymer foam materials shows poor surface adhesion and limited functionality, which greatly restricts its potential applications. Fabrication of advanced PDMS foam materials with multiple functionalities remains a critical challenge. In this study, unprecedented self-adhesive PDMS foam materials are reported with worm-like rough structure and reactive groups for fabricating multifunctional PDMS foam nanocomposites decorated with MXene/cellulose nanofiber (MXene/CNF) interconnected network by a facile silicone foaming and dip-coating strategy followed by silane surface modification. Interestingly, such self-adhesive PDMS foam produces strong interfacial adhesion with the hybrid MXene/CNF nano-coatings. Consequently, the optimized PDMS foam nanocomposites have excellent surface super-hydrophobicity (water contact angle of ≈159o), tunable electrical conductivity (from 10-8 to 10 S m-1), stable compressive cyclic reliability in both wide-temperature range (from -20 to 200 °C) and complex environments (acid, sodium, and alkali conditions), outstanding flame resistance (LOI value of >27% and low smoke production rate), good thermal insulating performance and reliable strain sensing in various stress modes and complex environmental conditions. It provides a new route for the rational design and development of advanced PDMS foam nanocomposites with versatile multifunctionalities for various promising applications such as intelligent healthcare monitoring and fire-safe thermal insulation. [ABSTRACT FROM AUTHOR]

We report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific extracellular vesicle (EV) purification system for early detection of HCC by performing digital scoring on the purified EVs. Earlier detection of HCC creates more opportunities for curative therapeutic interventions. EVs are present in circulation at relatively early stages of disease, providing potential opportunities for HCC early detection. We develop an HCC EV purification system (i.e., EV Click Chips) by synergistically integrating covalent chemistry-mediated EV capture/release, multimarker antibody cocktails, nanostructured substrates, and microfluidic chaotic mixers. We then explore the translational potential of EV Click Chips using 158 plasma samples of HCC patients and control cohorts. The purified HCC EVs are subjected to reverse-transcription droplet digital PCR for quantification of 10 HCC-specific mRNA markers and computation of digital scoring. The HCC EV-derived molecular signatures exhibit great potential for noninvasive early detection of HCC from at-risk cirrhotic patients with an area under receiver operator characteristic curve of 0.93 (95% CI, 0.86 to 1.00; sensitivity = 94.4%, specificity = 88.5%).

Supramolecular silicone elastomer is a promising material for sustainable development. Here, quadruple hydrogen bonded ureidopyrimidinone (UPy) units were grafted onto high molecular weight polydimethylsiloxanes (PDMS), providing a novel supramolecular silicone elastomer. The high molecular weight PDMS precursor was prepared through a cyclic trimeric phosphazene base catalyzed ring‐opening polymerization of Octamethylcyclotetrasiloxane (D4) and tetravinyltetramethylcyclotetrasiloxane (V4) with a well‐controlled vinyl content. Its side chains were modified by hydroxyl groups via a thiol‐ene reaction. Then UPy units were further grafted on the side chain of high molecular weight PDMS by the isocyanate‐hydroxy reaction. The mechanical and self‐healing properties of the elastomer can be controlled by adjusting the molecular weight of PDMS and the amount of UPy units. The obtained PDMS elastomers displayed excellent stretchability (elongation at break of 1513%), good self‐healing efficiency (76% at 60°C for 2 h), and high resilience (elastic recovery of 93% under 300% strain cyclic stretching). [ABSTRACT FROM AUTHOR]

Rotaxanes consisting of a high‐molecular‐weight axle and wheel components (macro‐rotaxanes) have high structural freedom, and are attractive for soft‐material applications. However, their synthesis remains underexplored. Here, we investigated macro‐rotaxane formation by the topological trapping of multicyclic polydimethylsiloxanes (mc‐PDMSs) in silicone networks. mc‐PDMS with different numbers of cyclic units and ring sizes was synthesized by cyclopolymerization of a α,ω‐norbornenyl‐functionalized PDMS. Silicone networks were prepared in the presence of 10–60 wt % mc‐PDMS, and the trapping efficiency of mc‐PDMS was determined. In contrast to monocyclic PDMS, mc‐PDMSs with more cyclic units and larger ring sizes can be quantitatively trapped in the network as macro‐rotaxanes. The damping performance of a 60 wt % mc‐PDMS‐blended silicone network was evaluated, revealing a higher tan δ value than the bare PDMS network. Thus, macro‐rotaxanes are promising as non‐leaching additives for network polymers. [ABSTRACT FROM AUTHOR]

Neuromuscular circuits (NMCs) are vital for voluntary movement, and effective models of NMCs are needed to understand the pathogenesis of, as well as to identify effective treatments for, multiple diseases, including Duchenne's muscular dystrophy and amyotrophic lateral sclerosis. Microfluidics are ideal for recapitulating the central and peripheral compartments of NMCs, but myotubes often detach before functional NMCs are formed. In addition, microfluidic systems are often limited to a single experimental unit, which significantly limits their application in disease modeling and drug discovery. Here, we developed a microfluidic platform (MFP) containing over 100 experimental units, making it suitable for medium-throughput applications. To overcome detachment, we incorporated a reactive polymer surface allowing customization of the environment to culture different cell types. Using this approach, we identified conditions that enable long-term co-culture of human motor neurons and myotubes differentiated from human induced pluripotent stem cells inside our MFP. Optogenetics demonstrated the formation of functional NMCs. Furthermore, we developed a novel application of the rabies tracing assay to efficiently identify NMCs in our MFP. Therefore, our MFP enables large-scale generation and quantification of functional NMCs for disease modeling and pharmacological drug targeting.

Objectives/hypothesisUnilateral ML is a commonly performed surgery for dysphonia secondary to glottic insufficiency. The safety of this procedure performed in the outpatient setting has not been extensively examined. The purpose of the study was to assess the safety of outpatient unilateral ML in adults and determine the incidence and timing of postoperative complications across two tertiary-care academic medical centers.Study designRetrospective chart review, METHODS: A review of patients undergoing unilateral ML at two tertiary-care academic centers from 2011 to 2017 was performed. Patients undergoing bilateral medialization laryngoplasty, revision surgery, or those undergoing additional laryngeal framework procedures including arytenoid adduction were excluded. Patient demographics, operative details, and perioperative and postoperative complications were recorded. Comparisons were made between those individuals who underwent inpatient versus outpatient ML.ResultsOne hundred three total procedures met inclusion criteria. Fifty-seven were performed as outpatient procedures, and 46 individuals were observed for at least 23 hours following surgery. Silastic or Gore-Tex implants were used in all but two surgeries. There were no postoperative complications in either setting, including hematoma, dyspnea, wound infections or seromas.ConclusionsThe incidence of adverse events during and immediately following unilateral ML is very low. Patients can be discharged safely the day of surgery without geographic restrictions.Level of evidence4 Laryngoscope, 129:1647-1649, 2019.

The use of biochemical signaling to derive smooth muscle cells (SMCs) from mesenchymal stem cells (MSCs) has been explored, but the induction of a fully functional SMC phenotype remains to be a major challenge. Cell morphology has been shown to regulate MSC differentiation into various lineages, including SMCs. We engineered substrates with microgrooves to induce cell elongation to study the mechanism underlying the MSC shape modulation in SMC differentiation. In comparison to those on flat substrates, MSCs cultured on engineered substrates were elongated with increased aspect ratios for both cell body and nucleus, as well as augmented cytoskeletal tensions. Biochemical studies indicated that the microgroove-elongated cells expressed significantly higher levels of SMC markers. MicroRNA analyses showed that up-regulation of miR-145 and the consequent repression of KLF4 in these elongated cells promoted MSC-to-SMC differentiation. Rho/ROCK inhibitions, which impair cytoskeletal tension, attenuated cell and nuclear elongations and disrupted the miR-145/KLF4 regulation for SMC differentiation. Furthermore, cell traction force measurements showed that miR-145 is essential for the functional contractility in the microgroove-induced SMC differentiation. Collectively, our findings demonstrate that, through a Rho-ROCK/miR-145/KLF4 pathway, the elongated cell shape serves as a decisive geometric cue to direct MSC differentiation into functional SMCs.

Based on sampling from Xiaoqing River of China and elimination experiments, this study first investigated spatial/seasonal profiles and fates of phenylmethylsiloxanes (PMSs), as modified products of dimethylsiloxanes (DMSs), in natural waterbody. Overall, the average water (6.7 ng/L) and sediment (28.5 ng/g dw) concentrations of total six cis-/trans- isomers of 2,4,6-triphenyl-2,4,6-trimethylcyclotrisiloxanes (P3) and 2,4,6,8-tetraphenyl-2,4,6,8-tetramethylcyclotetrasiloxanes (P4) in river segments located in industrial areas were respectively 7.37 and 6.13 times higher than those near residential areas, indicating that industrial activities may have larger contribution to PMSs emission than living activities. Compared with paired DMSs with same Si number, PMSs had lower hydrolysis but faster photolysis, and these two pathways influenced isomeric differences in river water: (1) slower hydrolysis of trans-isomers (t 1/2 = 45.6–334 h) than cis-isomers (t 1/2 = 38.1–251 h) might cause actual cis/trans ratios (0.18 for P3 and 0.092 for P4) lower than theoretical values (0.33 for P3 and 0.14 for P4) in water, especially in acidic (pH=6.1–6.3) and alkaline (pH=8.0–8.4) segments; (2) faster indirect photolysis of trans-isomers (t 1/2 = 54.7–177 h) than cis-isomers (t 1/2 = 73.4–191 h) might lead to larger mean cis/trans ratios in summer (0.31 for P3) with stronger illumination than those in winter (0.08 for P3). The Σ(P3 + P4) concentrations in 140 mussels (Anodonta woodiana) from 14 sites of the Xiaoqing River were

High performance microprobes for combined sensing of glucose and choline were fabricated using microcontact printing (μCP) to transfer choline oxidase (ChOx) and glucose oxidase (GOx) onto targeted sites on microelectrode arrays (MEAs). Most electroenzymatic sensing sites on MEAs for neuroscience applications are created by manual enzyme deposition, which becomes problematic when the array feature size is less than or equal to ∼100 μm. The μCP process used here relies on use of soft lithography to create features on a polydimethylsiloxane (PDMS) microstamp that correspond to the dimensions and array locations of targeted, microscale sites on a MEA. Precise alignment of the stamp with the MEA is also required to transfer enzyme only onto the specified microelectrode(s). The dual sensor fabrication process began with polyphenylenediamine (PPD) electrodeposition on all Pt microelectrodes to block common interferents (e.g., ascorbic acid and dopamine) found in brain extracellular fluid. Next, a chitosan film was electrodeposited to serve as an adhesive layer. The two enzymes, ChOx and GOx, were transferred onto different microelectrodes of 2 × 2 arrays using two different PDMS stamps and a microscope for stamp alignment. Using constant potential amperometry, the combined sensing microprobe was confirmed to have high sensitivity for choline and glucose (286 and 117 μA mM cm-2, respectively) accompanied by low detection limits (1 and 3 μM, respectively) and rapid response times (≤2 s). This work demonstrates the use of μCP for facile creation of multianalyte sensing microprobes by targeted deposition of enzymes onto preselected sites of a microelectrode array.

A simple, efficient procedure has been employed to effect intra- and inter-chain crosslinking of two commercially available thiolated poly(dimethylsiloxane) copolymers (T-PDMS) with 4–6% or 13–17% of mercaptopropyl side-chains. The thiol functional groups were converted to disulfides (D-PDMS) in chloroform solutions of I2. Importantly, the conditions employed avoid over-oxidation to other types of sulfur-containing species, and the concentration of T-PDMS during the crosslinking reaction dictated the rheological properties and liquid or solid nature of the D-PDMS. The procedure for obtaining the crosslinked copolymers is simpler than other approaches in the literature used to crosslink polysiloxane backbones and to modulate their properties. By changing the concentration of T-PDMS during the treatment with I2, the degree of intra- and inter-chain crosslinking can be controlled (as assessed qualitatively by the solid or liquid nature of the products and their viscoelastic properties). For each of the T-PDMS materials, there is a concentration threshold, above which products are solids, and below which they are oils. Liquid and solid materials were characterized using 1H and 13C solution-state and 13C solid-state NMR spectroscopy, respectively. They indicate greater than 90% conversion of thiols to disulfides in the presence of excess I2. The rheological behavior of the liquid products, solvent swelling ability of solid products, and the thermal stability of the reactants and products are described. Furthermore, the solid products exhibit some of the highest swelling values reported in the literature for poly(dimethylsiloxane) (PDMS) materials. As assessed by thermal gravimetric analyses, the disulfide-crosslinked materials are more stable thermally than the corresponding thiols. [ABSTRACT FROM AUTHOR]

Silicone elastomers are usually produced via addition or condensation curing by means of platinum‐ or tin‐based catalysis. The employed catalysts remain in the final rubber and cannot be recovered, thus creating various economic and environmental challenges. Herein, a light‐mediated curing method using multifunctional silacyclopropenes as crosslinker structures was introduced to create an effective alternative to the conventional industrial crosslinking. To evaluate the potential of the photoreaction a model study with small monofunctional silirenes was conducted. These investigations confirmed the required coupling reactivity upon irradiation and revealed an undesired rearrangement formation. Further optimization showed the reaction selectivity to be strongly influenced by the substitution of the three‐membered ring system and the reaction temperature. The synthesis of multifunctional silirenes was described based on the most suitable model compound to create active crosslinker scaffolds for their application in silicone curing. This photo‐controlled process produces catalyst and additive free elastomers from liquid silicones, including hydride‐, hydroxy‐, or vinyl terminated polydimethylsiloxanes. [ABSTRACT FROM AUTHOR]

Breast augmentations, commonly performed for aesthetic or medical reasons, often use silicone (polydimethylsiloxane [PDMS]) implants. Some patients develop complications like capsular contracture, where scar tissue forms around the implant. Previously, we used stimulated Raman scattering (SRS) microscopy to detect and quantify silicone in stained capsule tissue, finding a correlation between silicone amount and contracture severity. However, we suspected silicone loss during histological preparation, which includes multiple steps like formalin fixation and paraffin embedding. In this study, we assessed silicone loss by comparing adjacent tissue samples from the same capsule: one prepared conventionally and the other snap-frozen. SRS microscopy revealed that snap-frozen samples had roughly five times more silicone, indicating significant silicone loss during conventional preparation. Thus, measuring silicone in histologically prepared samples likely underestimates PDMS content., (© 2024 The Author(s). Journal of Biophotonics published by Wiley‐VCH GmbH.)

A method for the preparation of polydimethylsiloxanes with grafted methoxy-substituted dibenzoylmethanatoboron difluoride has been described. The structures of prepared polymers were confirmed using NMR, IR spectroscopy and gel permeation chromatography methods. Their thermal properties were investigated using thermal gravimetric analysis, differential scanning calorimetry and thermomechanical analysis. The prepared polymers had good thermal (Td5% up to 393 °C) and thermo-oxidative (Td5% = 413 °C) stability. The polymers started to transit in a viscous flow state at about 40 °C (for 3 a) and at about 20 °C (for 3 b). The viscoelastic characteristics of prepared polymers were determined in the sinusoidal oscillating vibrations mode. It was shown that the studied polymers at low frequencies at room temperature are viscoelastic fluids (G′ < G″). Increasing the frequency led to inversion (crossover) of dependences G′ and G″, which indicated the transition of polymers from viscous to elastomeric behavior characteristics, and the beginning of the formation of a physical network. Optical properties were studied using electron absorption, steady-state and time-resolved fluorescence spectroscopy. It was shown that intramolecular H-dimers exist in the ground state. The polymers studied had a bright fluorescence in the solution and in the solid state, consisting of bands of monomer and excimer emission. Thermally-activated delayed fluorescence was observed in the solution and the solid state. The prepared polymers possess intriguing properties that make them useful as optical materials, sensors or imaging agents. [ABSTRACT FROM AUTHOR]

Self‐healing polymer–carbon composites are seen as promising materials for future electronic devices, which must be able to restore not only their structural integrity but also electrical performance after cracking and wear. Despite multiple reports about self‐healing conductive elements, there is a lack of a broad fundamental understanding of correlation between viscoelasticity of such composites, their electrical properties, and self‐healing of their mechanical as well as electrical properties. Here, it is reported thorough investigation of electromechanical properties of blends of carbon black (CB) as conductive filler and viscoelastic polymers (polydimethylsiloxanes (PDMS) and polyborosiloxane (PBS)) with different relaxation times as matrices. It is shown that behavior of composites depends strongly on the viscoelastic properties of polymers. Low molecular polymer composite possesses high conductivity due to strong filler network formation, quick electrical, and mechanical properties restoration, but for this the ability is sacrificed to flow and ductility at large deformation (material is brittle). In contrary, high relaxation time polymer composite behaves elastically on small time and flows at large time scale due to weak filler network and can heal. However, the electrical properties are worse than that of carbon and viscous polymer and degrade with time. [ABSTRACT FROM AUTHOR]

Extracorporeal membrane oxygenation (ECMO) is a life support system that circulates the blood through an oxygenating system to temporarily (days to months) support heart or lung function during cardiopulmonary failure until organ recovery or replacement. Currently, the need for high levels of systemic anticoagulation and the risk for bleeding are main drawbacks of ECMO that can be addressed with a redesigned ECMO system. Our lab has developed an approach using microelectromechanical systems (MEMS) fabrication techniques to create novel gas exchange membranes consisting of a rigid silicon micropore membrane (SμM) support structure bonded to a thin film of gas-permeable polydimethylsiloxane (PDMS). This study details the fabrication process to create silicon membranes with highly uniform micropores that have a high level of pattern fidelity. The oxygen transport across these membranes was tested in a simple water-based bench-top set-up as well in a porcine in vivo model. It was determined that the mass transfer coefficient for the system using SµM-PDMS membranes was 3.03 ± 0.42 mL O2 min-1 m-2 cm Hg-1 with pure water and 1.71 ± 1.03 mL O2 min-1 m-2 cm Hg-1 with blood. An analytic model to predict gas transport was developed using data from the bench-top experiments and validated with in vivo testing. This was a proof of concept study showing adequate oxygen transport across a parallel plate SµM-PDMS membrane when used as a membrane oxygenator. This work establishes the tools and the equipoise to develop future generations of silicon micropore membrane oxygenators.

When a constraint is removed, confluent cells migrate directionally into the available space. How the migration directionality and speed increase are initiated at the leading edge and propagate into neighboring cells are not well understood. Using a quantitative visualization technique-Particle Image Velocimetry (PIV)-we revealed that migration directionality and speed had strikingly different dynamics. Migration directionality increases as a wave propagating from the leading edge into the cell sheet, while the increase in cell migration speed is maintained only at the leading edge. The overall directionality steadily increases with time as cells migrate into the cell-free space, but migration speed remains largely the same. A particle-based compass (PBC) model suggests cellular interplay (which depends on cell-cell distance) and migration speed are sufficient to capture the dynamics of migration directionality revealed experimentally. Extracellular Ca2+ regulated both migration speed and directionality, but in a significantly different way, suggested by the correlation between directionality and speed only in some dynamic ranges. Our experimental and modeling results reveal distinct directionality and speed dynamics in collective migration, and these factors can be regulated by extracellular Ca2+ through cellular interplay. Quantitative visualization using PIV and our PBC model thus provide a powerful approach to dissect the mechanisms of collective cell migration.

In this work, we introduce, to our knowledge, a new set of adhesion-based biomarkers for characterizing mammalian cells. Mammalian cell adhesion to the extracellular matrix influences numerous physiological processes. Current in vitro methods to probe adhesion focus on adhesive force to a single surface, which can investigate only a subcomponent of the adhesive, motility, and polarization cues responsible for adhesion in the 3D tissue environment. Here, we demonstrate a method to quantify the transhesive properties of cells that relies on the microscale juxtaposition of two extracellular matrix-coated surfaces. By multiplexing this approach, we investigate the unique transhesive profiles for breast cancer cells that are adapted to colonize different metastatic sites. We find that malignant breast cancer cells readily transfer to new collagen I surfaces, and away from basement membrane proteins. Integrins and actin polymerization largely regulate this transfer. This tool can be readily adopted in cell biology and cancer research to uncover, to our knowledge, novel drivers of adhesion (or de-adhesion) and sort cell populations based on complex phenotypes with physiological relevance.

Wound repair is a key feature distinguishing living from nonliving matter. Single cells are increasingly recognized to be capable of healing wounds. The lack of reproducible, high-throughput wounding methods has hindered single-cell wound repair studies. This work describes a microfluidic guillotine for bisecting single Stentor coeruleus cells in a continuous-flow manner. Stentor is used as a model due to its robust repair capacity and the ability to perform gene knockdown in a high-throughput manner. Local cutting dynamics reveals two regimes under which cells are bisected, one at low viscous stress where cells are cut with small membrane ruptures and high viability and one at high viscous stress where cells are cut with extended membrane ruptures and decreased viability. A cutting throughput up to 64 cells per minute-more than 200 times faster than current methods-is achieved. The method allows the generation of more than 100 cells in a synchronized stage of their repair process. This capacity, combined with high-throughput gene knockdown in Stentor, enables time-course mechanistic studies impossible with current wounding methods.

We report the cases of 2 women who had urethral bulking injections with polydimethylsiloxane for stress urinary incontinence with intrinsic sphincter deficiency and reported initial improvement of symptoms followed by rapid return of stress urinary incontinence several weeks later associated with extrusion of the bulking material. We hypothesize this unique adverse outcome could represent immune rejection of this urethral bulking agent.

This paper presents a study concerning the macroscale deformation of soft stamps for nanoimprint lithography. Composite stamps consisting of two or three layers were prepared with varying process parameters, and the bow of the stamps was investigated with an optical profilometer. Deflection measurements were compared with results from a mechanical model in order to prove its validity. The composite stamps were prepared from polydimethylsiloxane (S-PDMS) and OrmoStamp® layers on different substrate materials (silicon or AF-32-glass). The influence of selected preparation parameters on the deformation was investigated, such as layer thickness, curing, and hardbake temperatures, as well as UV-exposure intensities. It is discussed how an appropriate choice of preparation parameters can reduce the deformation, too. By decreasing the curing intensity of a thin OrmoStamp layer, coated on top of a silicon wafer, from 200 mW/cm2 to 2 mW/cm2, the deformation was reduced from 6 µm to 0. It is shown that the mechanical model is capable of predicting the deformation of composite stamps consisting of OrmoStamp layers on top of a silicon substrate. Further on, deformation results for S-PDMS top layers are presented and discussed. As a promising process option for the reduction of stamp deformations, a new, room temperature curable PDMS recipe is introduced. For composite stamps prepared with this material, the deformation value was reduced below 10 µm, compared to values ranging from 10 µm up to 127 µm for thermally cured S-PDMS (50°C or 70°C). Finally, different two-layer stamps were coated with an additional third layer and measured again, in order to investigate the deflection for tri-layered cases. The research is of high relevance for the fabrication and application of substrate conformal imprint lithography stamps with minimized deflection. [ABSTRACT FROM AUTHOR]

Biocompatible polymers, such as polydimethylsiloxane (PDMS), are the materials of choice for creating organ-on-a-chip microfluidic platforms. Desirable qualities include ease of fabrication, optical clarity, and hydrophobicity, the latter of which facilitates oxygen transport to encased cells. An emerging and important application of organ-on-a-chip technology is drug discovery; however, a potential issue for polymer-based microfluidic devices has been highlighted by recent studies with PDMS, which have demonstrated absorption (and thus loss) of hydrophobic drugs into PDMS under certain experimental conditions. Absorption of drug in the polymer can also lead to undesirable transfer of drug between adjacent microfluidic lines. Given the benefits of polymers, it is essential to develop a comprehensive understanding of drug absorption. In this study, we considered convection, dissolution, and diffusion of a drug within a polymer-based microfluidic device to characterize the dynamics of drug loss in a quantitative manner. We solved Ficks 2nd law of diffusion (unsteady diffusion-convection) by finite element analysis in COMSOL®, and experimentally validated the numerical model for loss of three hydrophobic molecules (rhodamine B, cyanine NHS ester, and paclitaxel) in PDMS. Drug loss, as well as the unintended mixing of drugs by adjacent microfluidic channels, depends strongly on platform design parameters, experimental conditions, and the physico-chemical properties of the drug, and can be captured in a simple quantitate relationship that employs four scalable dimensionless numbers. This simple quantitative framework can be used in the design of a wide range of polymer-based microfluidic devices to minimize the impact of drug absorption.

We demonstrate a facile, plasma free process to fabricate both reversibly and irreversibly sealed microfluidic chips using a PDMS-based adhesive polymer mixture. This is a versatile method that is compatible with current PDMS microfluidics processes. It allows for easier fabrication of multilayer microfluidic devices and is compatible with micropatterning of proteins for cell culturing. When combined with our Shrinky-Dink microfluidic prototyping, complete microfluidic device fabrication can be performed without the need for any capital equipment, making microfluidics accessible to the classroom.

Although it is well known that phospholipids self-assemble on hydrophilic plasma-oxidized PMDS surfaces (ox-PDMS) to form cell membrane mimetic bilayers, the temporal stability of phospholipid membranes on these surfaces is unknown. Here we report that phospholipid bilayers remain stable on solvent-cleaned ox-PDMS for at least 132 hours after preparation. Absent solvent cleaning, the bilayers were stable for only 36 hours. We characterized the phospholipid bilayers, i) through quantitative comparative analysis of the fluorescence intensity of phospholipid bilayers on ox-PDMS and phospholipid monolayers on native PDMS and, ii) through measurements of the diffusive mobility of the lipids through fluorescence recovery after photobleaching (FRAP). The fluorescence intensity of the phospholipid layer remained consistent with that of a bilayer for 132 hours. The evolution of the diffusive mobility of the phospholipids in the bilayer on ox-PDMS over time was similar to lipids in control bilayers prepared on glass surfaces. Solvent cleaning was essential for the long-term stability of the bilayers on ox-PDMS. Without cleaning in acetone and isopropanol, phospholipid bilayers prepared on ox-PDMS surfaces peeled off in large patches within 36 hours. Importantly, we find that phospholipid bilayers supported on solvent-cleaned ox-PDMS were indistinguishable from phospholipid bilayers supported on glass for at least 36 hours after preparation. Our results provide a link between the two common surfaces used to prepare in vitro biomimetic phospholipid membranes-i) glass surfaces used predominantly in fundamental biophysical experiments, for which there is abundant physicochemical information, with ii) ox-PDMS, the dominant material used in practical, applications-oriented systems to build micro-devices, topographically-patterned surfaces, and biosensors where there is a dearth of information.

An overlooked issue for field application of in situ performance reference compound (PRC) calibration methods is the validity of the assumption that both the sorption of a target compound and desorption of its corresponding PRC follow the first-order kinetics with the same rate constants under stagnant conditions. In the present study, disposable polydimethylsiloxane fibers of 2 sizes (7 and 35 µm) impregnated with 8 (13) C-labeled or deuterated PRCs were statically deployed into different marine sediments, from which the kinetics for sorption of the target compounds and desorption of the PRCs were characterized. Nonsymmetrical profiles were observed for exchange of the target analytes and their corresponding PRCs in sediment under stagnant conditions. The hysteretic desorption of PRCs in the kinetic regime may be ascribed to the low chemical potential between the fiber and sediment porewater, which reflects the inability of water molecules to rapidly diffuse through sediment to solvate the PRCs in the aqueous layer around the fiber surface. A moderate correlation (r = 0.77 and r = 0.57, p

It is now well established that, even within a single cell, multiple copies of the mitochondrial genome may be present (genetic heteroplasmy). It would be interesting to develop techniques to determine if and to what extent this genetic variation results in functional variation from one mitochondrion to the next (functional heteroplasmy). Measuring mitochondrial respiration can reveal the organelles' functional capacity for Adenosine triphosphate (ATP) production and determine mitochondrial damage that may arise from genetic or age related defects. However, available technologies require significant quantities of mitochondria. Here, we develop a technology to assay the respiration of a single mitochondrion. Our "micro-respirometer" consists of micron sized chambers etched out of borofloat glass substrates and coated with an oxygen sensitive phosphorescent dye Pt(II) meso-tetra(pentafluorophenyl)porphine (PtTFPP) mixed with polystyrene. The chambers are sealed with a polydimethylsiloxane layer coated with oxygen impermeable Viton rubber to prevent diffusion of oxygen from the environment. As the mitochondria consume oxygen in the chamber, the phosphorescence signal increases, allowing direct determination of the respiration rate. Experiments with coupled vs. uncoupled mitochondria showed a substantial difference in respiration, confirming the validity of the microchambers as single mitochondrial respirometers. This demonstration could enable future high-throughput assays of mitochondrial respiration and benefit the study of mitochondrial functional heterogeneity, and its role in health and disease.

We present a method for low-cost fabrication of polydimethylsiloxane (PDMS) tissue simulating phantoms with tunable scattering spectra, spanning visible, and near-infrared regimes. These phantoms use optical polishing agents (aluminum oxide powders) at various grit sizes to approximate in vivo tissue scattering particles across multiple size distributions (range: 17 to 3  μm). This class of tunable scattering phantoms is used to mimic distinct changes in wavelength-dependent scattering properties observed in tissue pathologies such as partial thickness burns. Described by a power-law dependence on wavelength, the scattering magnitude of these phantoms scale linearly with particle concentration over a physiologic range [μs′=(0.5 to 2.0  mm−1)] whereas the scattering spectra, specific to each particle size distribution, correlate to distinct exponential coefficients (range: 0.007 to 0.32). Aluminum oxide powders used in this investigation did not detectably contribute to the absorption properties of these phantoms. The optical properties of these phantoms are verified through inverse adding-doubling methods and the tolerances of this fabrication method are discussed.

Background: Electronic moxibustion (EM) was developed to minimize the side effects of traditional moxibustion, such as burns, and to overcome therapeutic compliances such as smoke or smell. Objectives: To investigate distributions and thermal stimulation of EM at various depths using silicon phantom and to compare this methodology to traditional indirect moxibustion (TIM). Methods: A silicon phantom composed of polydimethylsiloxane was heated and immersed in a hot plate containing warm water to set the phantom's temperature to that of biological tissue. K-type thermocouples were inserted into the phantom at depths of 0, 2, 5, 7, and 10 mm to measure temperature changes with thermal stimulation of EM or TIM placed on top of the phantom. Results: At the surface of the phantom, the peak temperature after applying TIM (55.04 ± 0.92°C [Δ23.79 ± 0.96°C]) was significantly higher than after EM (43.25 ± 1.95°C [Δ13.00 ± 2.23°C]), with both interventions reaching the highest temperature after 2 minutes. The temperature increase for TIM was also statistically significant compared to EM when measured at a depth of 2 mm. For the experimental setting with TIM, after reaching peak surface temperature, a rapid decrease was observed at the surface and 2 mm while EM showed a much more gradual decline. There was no significant difference in temperature change between the groups at depths of 5, 7, and 10 mm. Conclusion: TIM resulted in a higher temperature rise compared to EM at the surface and at a 2 mm depth reaching over 50°C, which creates risk of burns. Thermal stimulation with EM had a lower risk of burns with temperature increment not being statistically different from TIM below the depth of 5 mm. [ABSTRACT FROM AUTHOR]

Transformation of H2PtCl6 over time under the action of 2-octanol has been studied by NMR, IR spectroscopy, GLC, and GC/MS. It has been found for the first time that the alcohol in a H2PtCl6 ⋅ 6H2O–2-octanol solution is hydrochlorinated to give 2-chlorooctane. Dehydrated platinum chlorides catalyze the elimination of methyl groups in trimethylchlorosilane and hexamethyldisiloxane, which leads to the formation of polydimethylsiloxanes. It has been assumed that the resulting π-complex of H2PtCl4 with octene-1 is not stable in a hydrochloric medium and rapidly decomposes to release chloroalkyl. [ABSTRACT FROM AUTHOR]

Introduction: During the novel coronavirus disease 2019 pandemic, health care workers experienced facial problems from prolonged use of N95 masks, including skin irritation, pigmentation changes, and contact dermatitis. We assessed the use of hydrocolloid dressing versus dimethicone cream to prevent skin breakdown among military health care workers while wearing an N95., Materials and Methods: Participants were recruited using convenience and snowball sampling in this nonblinded, randomized, cross-over study with 2 active treatments, hydrocolloid dressing and dimethicone cream, across 3 time points. The skin was assessed using photographs and subepidermal moisture scanner (SEM). N95 seal integrity was assessed using qualitative fit test. Institutional review board approval was obtained from the Madigan Army Medical Center Institutional Review Board., Results: Among the 73 participants, wearing an N95 alone versus with dimethicone cream or hydrocolloid dressing caused more adverse skin reactions. There were no significant differences in qualitative fit test failure rate between groups. Participants experienced minimal to no dizziness, loss of energy/tiredness/fatigue, claustrophobia, shortness of breath, difficulty breathing, and dry or itchy eyes. For all interventions, wearing an N95 did not interfere with participants' concentration, verbal communication, hearing, vision, and, importantly, delivery of care., Conclusions: Using a skin protectant with an N95 may prevent adverse skin reactions while preserving health care workers' ability to safely and competently care for patients in routine and pandemic conditions., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background Context: Cutibacterium acnes (C. acnes) is a gram-positive facultative anaerobe found in the deep sebaceous follicles of the skin on the shoulder and back. C. acnes has been increasingly recognized as a pathogen in spinal surgical site infection (SSI) especially in the presence of instrumentation.Purpose: This study assesses whether a silver carboxylate-doped titanium dioxide-polydimethylsiloxane (TiO2-PDMS) coating can decrease C. acnes adherence and biofilm formation on PEEK and four other commonly used spinal implant materials, stainless steel, cobalt chromium, titanium, and titanium alloy.Study Design: We compared the adherence of C. acnes over 24 hours between uncoated, 95:5 TiO2 to PDMS ratio with 10× silver carboxylate coating and a 100% silver carboxylate coating on each implant material, which were uniformly saw cut and sterilized. Implants were then subjected to scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM).Methods: Samples were coated using 95:5 TiO2-PDMS 10× silver carboxylate, 100% silver carboxylate, or left uncoated. C. acnes was applied onto the samples and allowed to adhere for periods of 4, 8, 12, 16, or 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total of 24 hours. SEM and confocal laser scanning microscope were used to visualize all samples for the presence of biofilm and quantification of C. acnes adherence at each time point.Results: The 95:5 TiO2-PDMS 10× silver carboxylate coating was able to significantly decrease C. acnes adherence on PEEK after 8, 12, 16, and 20 hours of adherence. No statistical difference was found between the 95:5 TiO2-PDMS 10× silver carboxylate coating and the 100% silver carboxylate positive control. We previously observed extensive C. acnes biofilm formation on uncoated PEEK, but none on PEEK coated with either the 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating . Furthermore, no biofilm formation was observed on stainless steel, cobalt chromium, titanium, and titanium alloy coated with 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating.Conclusion: A 95:5 TiO2-PDMS 10× silver carboxylate coating decreases C. acnes adhesion and prevents biofilm formation on PEEK and other common orthopedic implant materials.Clinical Significance: A 95:5 TiO2-PDMS 10× silver carboxylate coating may help decrease spinal SSI due to C. acnes, especially in procedures with instrumentation. [ABSTRACT FROM AUTHOR]

Silver-based topical treatments have seen widespread use for the management of burns due to silver's antimicrobial activity. Recent studies suggest that silver nanoparticles could negatively affect healing time due to their toxic effect on keratinocytes and fibroblasts at higher concentrations. Zinc oxide antimicrobial activity has been demonstrated in vitro, and results from animal studies are promising for burn management. At our ABA-verified pediatric burn center, the use of silver sulfadiazine cream ("Silvadene") has been slowly replaced by a zinc oxide/dimethicone spray-on solution ("Touchless Spray"). The dimethicone allows the spray to be occlusive without interfering with clothing, yet easily removed as opposed to Silvadene cream which requires wound scrubbing to remove and replace; potentially improving patient adherence with at-home treatments. This is the first study of zinc oxide's efficacy as a burn wound management agent in humans. We sought to compare the efficacy of silver sulfadiazine and that of zinc oxide/dimethicone to determine whether zinc oxide/dimethicone, in its easy-to-use form, is a viable alternative to silver sulfadiazine. We conducted a retrospective review of the electronic medical records of all patients treated for perineal, genital, perianal, suprapubic, or buttocks burn wounds at a large pediatric-verified burn center from January 1, 2014 to October 28, 2019. Only patients with superficial second-degree scald burns that arrived at our institution less than 24 hours after injury were included. Of a total 52 patients identified, 27 patients received silver sulfadiazine while 25 received zinc oxide/dimethicone. After initial evaluation and treatment by the burn team, all patients were followed up at our weekly burn clinic until complete healing was achieved. We retrospectively extracted demographic data, wound size, depth, and location, management strategies, time to complete healing, and incidence of infectious and noninfectious complications. The control group contained patients with total body surface area burns significantly greater than the zinc oxide/dimethicone group likely due to selective treatment when zinc oxide/dimethicone was first introduced at our facility. Time to healing was significantly lower in the zinc oxide/dimethicone intervention group (12.16 ± 8.644 days) than the silver sulfadiazine control group (16.89 ± 11.342 days). No infections were observed. Limitations include the relatively small sample sizes and differences in the size of burn wounds that confounded our results and likely negatively affected healing time in the control group. The zinc oxide/dimethicone group had a significantly lower healing time than the silver sulfadiazine group in the treatment of pediatric burns to the perineum, genitalia, suprapubis, and buttocks. Zinc oxide/dimethicone may prove to be a useful tool for treating burn wounds, and further study is needed to determine its efficacy and safety. [ABSTRACT FROM AUTHOR]