Mechanically Tunable Transmittance Convection Shield for Dynamic Radiative Cooling.

Radiative cooling is the process to dissipate heat to the outer space through an atmospheric window (8-13 µm), which has great potential for energy savings in buildings. However, the traditional "static" spectral characteristics of radiative cooling materials may result in overcooling during the cold season or at night, necessitating the development of dynamic spectral radiative cooling for enhanced energy saving potential. In this study, we showcase the realization of dynamic radiative cooling by modulating the heat transfer process using a tunable transmittance convection shield (TTCS). The transmittance of the TTCS in both solar spectrum and atmospheric window can be dynamically adjusted within ranges of 28.8-72.9 and 27.0-80.5%, with modulation capabilities of ΔTsolar = 44.1% and ΔT8-13 µm = 53.5%, respectively. Field measurements demonstrate that through the modulation, the steady-state temperature of the TTCS architecture is 0.3 °C lower than that of a traditional radiative cooling architecture during the daytime and 3.3 °C higher at nighttime, indicating that the modulation strategy can effectively address the overcooling issue, offering an efficient way of energy saving through dynamic radiative cooling.

Scalable Colored Subambient Radiative Coolers Based on a Polymer-Tamm Photonic Structure.

Daytime radiative coolers cool objects below the air temperature without any electricity input, while most of them are limited by a silvery or whitish appearance. Colored daytime radiative coolers (CDRCs) with diverse colors, scalable manufacture, and subambient cooling have not been achieved. We introduce a polymer-Tamm photonic structure to enable a high infrared emittance and an engineered absorbed solar irradiance, governed by the quality factor (Q-factor). We theoretically determine the theoretical thresholds for subambient cooling through yellow, magenta, and cyan CDRCs. We experimentally fabricate and observe a temperature drop of 2.6-8.8 °C on average during the daytime and 4.0-4.4 °C during the nighttime. Furthermore, we demonstrate a scalable-manufactured magenta CDRC with a width of 60 cm and a length of 500 cm by a roll-to-roll deposition technique. This work provides guidelines for large-scale CDRCs and offers unprecedented opportunities for potential applications with energy-saving, aesthetic, and visual comfort demands.

Self-Patterning of Highly Stretchable and Electrically Conductive Liquid Metal Conductors by Direct-Write Super-Hydrophilic Laser-Induced Graphene and Electroless Copper Plating.

Stretchable electrodes are desirable in flexible electronics for the transmission and acquisition of electrical signals, but their fabrication process remains challenging. Herein, we report an approach based on patterned liquid metals (LMs) as stretchable electrodes using a super-hydrophilic laser-induced graphene (SHL-LIG) process with electroless plating copper on a polyimide (PI) film. The LMs/SHL-LIG structures are then transferred from the PI film to an Ecoflex substrate as stretchable electrodes with an ultralow sheet resistance of 3.54 mΩ per square and excellent stretchability up to 480% in elongation. Furthermore, these electrodes show outstanding performances of only 8% electrical resistance changes under a tensile strain of 300%, and strong immunity to temperature and pressure changes. As demonstration examples, these electrodes are integrated with a stretchable strain sensing system and a smart magnetic soft robot toward practical applications.

Scalable-Manufactured Metamaterials for Simultaneous Visible Transmission, Infrared Reflection, and Microwave Absorption.

Scalable manufacturing of metamaterials with multispectral manipulation capabilities remains highly challenging, which was generally circumvented by integrating several single-spectral metamaterials, potentially leading to complex processes, large thicknesses, and limited fabrication size. We experimentally demonstrate a standalone and scalable-manufactured multispectral metamaterial featuring simultaneous visible transmission, infrared reflection, and microwave absorption. The prepared multispectral metamaterial with an area of 255 cm2 exhibits a visible transmittance of 74.5% at wavelengths of 400-700 nm (the highest 80.2% at 510 nm), a thermal emissivity of 0.08 at the infrared (IR) wavelengths of 2.5-20 µm (the lowest 0.03 at 19.5 µm), and a microwave absorptance of 63.4% at frequencies of 8.2-12.4 GHz (the near-perfect 97.4% at 11.5 GHz) on average with a deep-subwavelength thickness of λ/47. The deep-subwavelength multispectral metamaterial consists of a submillimeter-thick polyethylene terephthalate dielectric spacer sandwiched by a patterned ultrathin metal and a metal mesh back-reflector with ultralow sheet resistances. Unlike the conventional optically transparent microwave absorbers made from indium tin oxides, the surface plasmonic modes can be excited within the submillimeter-thick multispectral metamaterial, bringing about the gap plasmon polaritons-induced microwave attenuation, together with the excellent visible transparency and high IR reflection/low IR emissivity. This work may inspire the designs and practical production of standalone multispectral metamaterials and benefit the protection against ubiquitous IR and microwave reconnaissance without impeding visual observation.

Low-Dose Sirolimus Immunoregulation Therapy in Patients with Active Rheumatoid Arthritis: A 24-Week Follow-Up of the Randomized, Open-Label, Parallel-Controlled Trial.

BACKGROUND: We have reported previously the insufficient absolute number or functional defects of regulatory T cells (Tregs) in patients with rheumatoid arthritis (RA), challenging conventional unspecific immunosuppressive therapy. Sirolimus, a mTOR inhibitor, is reported to allow growth of functional Tregs; here, we investigated the efficacy of low-dose sirolimus combined with conventional immunosuppressants (sirolimus immunoregulation therapy) for RA treatment with lower side effects and better tolerance. METHODS: In this nonblinded and parallel-group trial, we randomly assigned 62 patients to receive conventional glucocorticoids and immunosuppressants with or without sirolimus at a dosage of 0.5 mg on alternate days for 24 weeks in a 2 : 1 ratio. The demographic features, clinical manifestations, and laboratory indicators including peripheral blood lymphocyte subgroups and CD4+T subsets were compared before and after the treatment. RESULTS: Finally, 37 patients in the sirolimus group and 18 in the conventional treated group completed the 6-month study. By 24 weeks, the patients with sirolimus experienced significant reduction in disease activity indicators including DAS28, ESR, and the number of tender joints and swollen joints (p < 0.001). Notably, they had a higher level of Tregs as compared with those with conventional therapy alone (p < 0.05), indicating that sirolimus could partly restore the reduced Tregs. Concomitantly, their usage of immunosuppressants for controlling disease activity was decreased as compared with the conventional group with no difference in blood routine, and liver and renal functions both before and after the treatment of sirolimus and between the two groups (p > 0.05). CONCLUSIONS: Low-dose sirolimus immunoregulatory therapy selectively upregulated Tregs and partly replaced the usage of immunosuppressants to control disease activity without overtreatment and evaluable side effect. Further study is required using a large sample of RA patients treated with sirolimus for a longer period. This trial is registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/showproj.aspx?proj=17245).

Assessment of column aerosol optical properties using ground-based sun-photometer at urban Harbin, Northeast China.

Aerosol plays a key role in determining radiative balance, regional climate and human health. Severe air pollution over Northeast China in recent years urges more comprehensive studies to figure out the adverse effects caused by excessive aerosols. In this study, column aerosol measurements over urban Harbin, a metropolis located at the highest latitude in Northeast China, during May 2016 to March 2017 were conducted using a CIMEL sun-photometer to analyze local aerosol properties and its variation from different aspects. According to the observations, aerosol optical depth at 440nm (AOD440) ranges from 0.07 up to 1.54, and the large variability in both AOD440 and Angstrom Exponent (AE440-870) indicates the frequent change of aerosol types due of different emission sources. Coarse mode particles dominated Harbin during the studying period because of the long-range transported dust and probably the suspended snow crystals in winter. As the wavelength increases, relatively consistent decrease trends of single scattering albedo (SSA) and asymmetry factor (ASY) were observed in spring, autumn, and winter, indicating the presence of absorbing polluted aerosols. Mixed type (MIX) aerosol dominated the study region with a total percentage of 34%, and biomass burning and urban industry (BB/UI), clean continental (CC), and desert dust (DD) aerosols were found to be 31%, 27%, and 8%, respectively. The current work fills up the optical characteristics of aerosols in Harbin, and will contribute to the in-depth understanding of local aerosol variation and regional climate change over Northeast China.

[Comparison of two preparation methods applied in tanshinone II(A)-loaded PLGA nanoparticles].

OBJECTIVE: To optimize formulation of tanshinone II(A)-loaded PLGA nanoparticles and compare the difference of two methods in preparation and quality of nanoparticles. METHOD: The two methods were nanoprecipitation method and emulsion-evaporation method. Single factor experiments and central composite design and response surface method were used to optimize the formulation of nanoparticles. The nanoparticles were characterized at size, morphology, entrapment efficiency, drug loading, drug recovery rate, crystallinity and drug release in vitro. RESULT: The mean diameters were 225 nm and 183 nm, the entrapment efficiency were 95.49% and 87.99%, the drug loading were 2.03% and 0.16%, and the drug recovery rates were 38.42% and 17.59% respectively for nanoprecipitation method and emulsion-evaporation method. CONCLUSION: Nanoprecipitation method was better than emulsion-evaporation method for preparation of tanshinone II(A)-loaded PLGA nanoparticles.