Thread size and polymer composition are critical properties to consider for achieving a positive healing outcome with a wound dressing. Three-dimensional (3D) printed scaffolds and electrospun mats both offer distinct advantages as replaceable wound dressings. This research aims to determine if the thread size and polymer compositions of the scaffolds affect skin wound healing outcomes, an aspect that has not been adequately explored. Using a modular polymer platform, four polyester direct-write 3D printed scaffolds and electrospun mats were fabricated into wound dressings. The dressings were applied to splinted, full thickness skin wounds in an excisional wound rat model and evaluated against control wounds to which no dressing was applied. Wound closure rates and reduction of the wound bed width were not affected by the thread size or polymer composition. However, epidermal thickness was larger in wounds treated with electrospun dressings and was slightly affected by the polymer composition. Two of the four tested polymer compositions lead to delayed reorganization of granulation tissues. Moreover, enhanced angiogenesis was seen in wounds treated with 3D printed dressings compared to those treated with electrospun dressings. The results from this study can be used to inform the choice of dressing architecture and polymer compositions to achieve positive wound healing outcomes.

Pressure-sensitive adhesives (PSAs) such as sticky notes and labels are a ubiquitous part of modern society. PSAs with a wide range of peel adhesion strength are designed by tailoring the bulk and surface properties of the adhesive. However, designing an adhesive with strong initial adhesion but showing an on-demand decrease in adhesion has been an enduring challenge in the design of PSAs. To address this challenge, we designed alkoxyphenacyl-based polyurethane (APPU) PSAs that show a photoactivated increase and decrease in peel strength. With increasing time of light exposure, the failure mode of our PSAs shifted from cohesive to adhesive failure, providing residue-free removal with up to 83% decrease in peel strength. The APPU-PSAs also adhere to substrates submerged underwater and show a similar photoinduced decrease in adhesion strength.

The effect of polymer side chain on extrusion-based direct-write 3D printing and rheology is examined. Longer side chain length improves printability at ambient temperatures.

We report a novel pathway for the reductive activation of CO2 by the [NiIII(OMe)(P(C6H3-3-SiMe3-2-S)3)]– complex, yielding the [NiIII(κ1-OCO˙–)(P(C6H3-3-SiMe3-2-S)3)]– complex.

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Three-dimensional (3D) printing offers the unprecedented ability to create medical devices with complex architectures matched to the patient’s anatomy. However, the development of 3D printable synthetic polymers for biomedical applications has been relatively slow. Here, we present the synthesis and characterization of a library of single-component, undiluted, modular multifunctional polyesters for extrusion-based direct-write 3D printing (EDP). The polyesters were synthesized using carbodiimide-mediated polyesterification of pendant functionalized diols and succinic acid and characterized using 1H NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and rheology. The rheology was characterized by using small amplitude oscillatory shear rheology and at steady-state shear flow conditions. The viscoelasticity of the polyesters was characterized by plotting master curves using the time–temperature superposition (TTS) principle, which were then validated by Van Gurp-Palmen and Cole–Cole plots. The 3D printability of the polyesters was assessed on the basis of several key parameters including the ability to extrude as continuous filaments, retain the printed shape, form multilayer constructs, and form bridge-spanning filaments without significant sagging or collapse. The rheological characterization suggests that the polyesters are unentangled melts that facilitate printing at ambient temperatures without the use of external additives or solvents. The presence of supramolecular interactions inducing pendant functional groups forms a temporary, physical cross-link-like network that enables 3D shape retention. The insights from this study will further assist in the design and characterization of 3D printable polymer melts for biomedical applications and standardizing the assessment of polymer 3D printability.

the whole operating bandwidth, and a peak value appears at 67.5 GHz.Simulated E(yz)-and H(xz)-plane radiation patterns at 40, 50, 60, and 70 GHz are shown in Figure 4. It can be observed that the antenna can present unidirectional radiation patterns with very small backward radiation. The E-plane SLL is always kept small, but the H-plane SLL is slightly distorted due to the radiation of the currents on the vertical walls of the stairs and the connector. If judged by the SLL, the bandwidth can still cover a frequency band from 30.6 to around 70 GHz. Because of the same reason, the cross-polarization over the whole operating frequency band is around À10 dB.Measurements of the radiation patterns are performed from 50 to 75 GHz due to limitation of the in-house measurement system. Meanwhile, measurements are done in the upper half plane, i.e., 0 y 90 , because of the same reason. Figure 5 gives comparisons between the simulated and the measured radiation patterns at 50, 60, and 70 GHz. In the figure, simulations agree well with measurements, especially in terms of the copolarization patterns, proving the validity of all simulations in this article. As far as the cross-polarization is concerned, the measured results are larger than the simulated ones by around 5 dB. CONCLUSIONA wideband mm-wave CBA is studied in this article, and its RBD exciter is fabricated on a substrate along with the feeding network. With the help of the elliptical composite cavity and the RBD exciter, a maximum operating bandwidth covering 30.6-70 GHz and a broadside gain of 8.2-11.8 dBi can be achieved for SWR 2 and stable radiation patterns. This antenna can also be easily scaled upwards to higher frequencies due to its large electrical dimensions and no extremely fine structures in this design. Meanwhile, it is also suitable for integrated mm-wave system applications, in which integrated transceiver can be placed at the vertexes of the RBD or on the microstrip line. ACKNOWLEDGMENTS ABSTRACT:A compact circularly polarized circular microstrip tag antenna designed for RFID UHF band is presented. The proposed tag antenna is excited by using microstrip-line coupling-feed method. By choosing the proper lengths of two short-circuited arc microstrip lines and its coupling distance, good complex impedance matching can be obtained. Moreover, a cross slot of unequal arm lengths embedded in a circular patch is used to achieve compact circularly polarized operation. The measured 10-dB return-loss bandwidth of the tag antenna is 40 MHz (901-941 MHz), while the 3-dB axial-ratio bandwidth is 6 MHz (912-918 MHz). Further experiment shows that the Figure 5 Results for signal s 4

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