Corner- and edge-mode enhancement of near-field radiative heat transfer.

It is well established that near-field radiative heat transfer (NFRHT) can exceed Planck's blackbody limit1 by orders of magnitude owing to the tunnelling of evanescent electromagnetic frustrated and surface modes2-4, as has been demonstrated experimentally for NFRHT between two large parallel surfaces5-7 and between two subwavelength membranes8,9. However, although nanostructures can also sustain a much richer variety of localized electromagnetic modes at their corners and edges10,11, the contributions of such additional modes to further enhancing NFRHT remain unexplored. Here we demonstrate both theoretically and experimentally a physical mechanism of NFRHT mediated by the corner and edge modes, and show that it can dominate the NFRHT in the 'dual nanoscale regime' in which both the thickness of the emitter and receiver, and their gap spacing, are much smaller than the thermal photon wavelengths. For two coplanar 20-nm-thick silicon carbide membranes separated by a 100-nm vacuum gap, the NFRHT coefficient at room temperature is both predicted and measured to be 830 W m-2 K-1, which is 5.5 times larger than that for two infinite silicon carbide surfaces separated by the same gap, and 1,400 times larger than the corresponding blackbody limit accounting for the geometric view factor between two coplanar membranes. This enhancement is dominated by the electromagnetic corner and edge modes, which account for 81% of the NFRHT between the silicon carbide membranes. These findings are important for future NFRHT applications in thermal management and energy conversion.

Zn-based batteries for sustainable energy storage: strategies and mechanisms.

Batteries play a pivotal role in various electrochemical energy storage systems, functioning as essential components to enhance energy utilization efficiency and expedite the realization of energy and environmental sustainability. Zn-based batteries have attracted increasing attention as a promising alternative to lithium-ion batteries owing to their cost effectiveness, enhanced intrinsic safety, and favorable electrochemical performance. In this context, substantial endeavors have been dedicated to crafting and advancing high-performance Zn-based batteries. However, some challenges, including limited discharging capacity, low operating voltage, low energy density, short cycle life, and complicated energy storage mechanism, need to be addressed in order to render large-scale practical applications. In this review, we comprehensively present recent advances in designing high-performance Zn-based batteries and in elucidating energy storage mechanisms. First, various redox mechanisms in Zn-based batteries are systematically summarized, including insertion-type, conversion-type, coordination-type, and catalysis-type mechanisms. Subsequently, the design strategies aiming at enhancing the electrochemical performance of Zn-based batteries are underscored, focusing on several aspects, including output voltage, capacity, energy density, and cycle life. Finally, challenges and future prospects of Zn-based batteries are discussed.

Precisely Tailoring WSe2 Polarity via van der Waals Bismuth-Gold Modulated Contact.

Creating high-quality contacts between high-melting-point metals and delicate two-dimensional (2D) semiconductors poses a critical challenge to polarity control due to inevitable chemical disorder and Fermi-level pinning observed in the contact regions. Here, we report a van der Waals (vdW) integration strategy to precisely tailor the WSe2 polarity by meticulously modulating metal contact compositions. Controlling the low-melting-point bismuth (Bi) thickness effectively modulates the Bi/Au dominant contact with WSe2. This facilitates the precise polarity transformation between n-type, ambipolar, and p-type, with exceptional field-effect mobilities of 200 cm2 V-1 s-1 for electrons and 136 cm2 V-1 s-1 for holes. Within this vdW geometry, we further demonstrate the fundamental electrical components such as diodes and complementary inverters with enhanced rectification ratios and voltage gains. Our results showcase an effective and compatible with mass manufacturing method for precise polarity modulation of 2D semiconductors, providing a promising pathway toward large-scale high-performance 2D electronics and integrated circuits.

Ultrafine Asymmetric Soft/Stiff Nanohybrids with Tunable Patchiness via a Dynamic Surface-Mediated Assembly.

Asymmetric soft-stiff patch nanohybrids with small size, spatially separated organics and inorganics, controllable configuration, and appealing functionality are important in applications, while the synthesis remains a great challenge. Herein, based on polymeric single micelles (the smallest assembly subunit of mesoporous materials), we report a dynamic surface-mediated anisotropic assembly approach to fabricate a new type of small asymmetric organic/inorganic patch nanohybrid for the first time. The size of this asymmetric organic/inorganic nanohybrid is ∼20 nm, which contains dual distinct subunits of a soft organic PS-PVP-PEO single micelle nanosphere (12 nm in size and 632 MPa in Young' modulus) and stiff inorganic SiO2 nanobulge (∼8 nm, 2275 MPa). Moreover, the number of SiO2 nanobulges anchored on each micelle can be quantitatively controlled (from 1 to 6) by dynamically tuning the density (fluffy or dense state) of the surface cap organic groups. This small asymmetric patch nanohybrid also exhibits a dramatically enhanced uptake level of which the total amount of intracellular endocytosis is about three times higher than that of the conventional nanohybrids.

ESRP1-mediated biogenesis of circPTPN12 inhibits hepatocellular carcinoma progression by PDLIM2/ NF-κB pathway.

BACKGROUND: Emerging evidence indicates the pivotal involvement of circular RNAs (circRNAs) in cancer initiation and progression. Understanding the functions and underlying mechanisms of circRNAs in tumor development holds promise for uncovering novel diagnostic indicators and therapeutic targets. In this study, our focus was to elucidate the function and regulatory mechanism of hsa-circ-0003764 in hepatocellular carcinoma (HCC). METHODS: A newly discovered hsa-circ-0003764 (circPTPN12) was identified from the circbase database. QRT-PCR analysis was utilized to assess the expression levels of hsa-circ-0003764 in both HCC tissues and cells. We conducted in vitro and in vivo experiments to examine the impact of circPTPN12 on the proliferation and apoptosis of HCC cells. Additionally, RNA-sequencing, RNA immunoprecipitation, biotin-coupled probe pull-down assays, and FISH were employed to confirm and establish the relationship between hsa-circ-0003764, PDLIM2, OTUD6B, P65, and ESRP1. RESULTS: In HCC, the downregulation of circPTPN12 was associated with an unfavorable prognosis. CircPTPN12 exhibited suppressive effects on the proliferation of HCC cells both in vitro and in vivo. Mechanistically, RNA sequencing assays unveiled the NF-κB signaling pathway as a targeted pathway of circPTPN12. Functionally, circPTPN12 was found to interact with the PDZ domain of PDLIM2, facilitating the ubiquitination of P65. Furthermore, circPTPN12 bolstered the assembly of the PDLIM2/OTUD6B complex by promoting the deubiquitination of PDLIM2. ESRP1 was identified to bind to pre-PTPN12, thereby fostering the generation of circPTPN12. CONCLUSIONS: Collectively, our findings indicate the involvement of circPTPN12 in modulating PDLIM2 function, influencing HCC progression. The identified ESRP1/circPTPN12/PDLIM2/NF-κB axis shows promise as a novel therapeutic target in the context of HCC.

The regulation of Tfh cell differentiation by ß-hydroxybutyrylation modification of transcription factor Bcl6.

Transcriptional repressor B cell lymphoma 6 (Bcl6) is a major transcription factor involved in Tfh cell differentiation and germinal center response, which is regulated by a variety of biological processes. However, the functional impact of post-translational modifications, particularly lysine ß-hydroxybutyrylation (Kbhb), on Bcl6 remains elusive. In this study, we revealed that Bcl6 is modified by Kbhb to affect Tfh cell differentiation, resulting in the decrease of cell population and cytokine IL-21. Furthermore, the modification sites are identified from enzymatic reactions to be lysine residues at positions 376, 377, and 379 by mass spectrometry, which is confirmed by site-directed mutagenesis and functional analyses. Collectively, our present study provides evidence on the Kbhb modification of Bcl6 and also generates new insights into the regulation of Tfh cell differentiation, which is a starting point for a thorough understanding of the functional involvement of Kbhb modification in the differentiations of Tfh and other T cells.

Multiomics sequencing goes spatial.

Microfluidic channels provide a means to deliver barcodes encoding spatial information to a tissue, which allows co-profiling of gene expression and proteins of interest in a spatially resolved manner.

Pre- and Post-treatment Double-Sequential-Point Dynamic Radiomic Model in the Response Prediction of Gastric Cancer to Neoadjuvant Chemotherapy: 3-Year Survival Analysis.

BACKGROUND: Prognosis prediction of patients with gastric cancer after neoadjuvant chemotherapy is suboptimal. This study aims to develop and validate a dynamic radiomic model for prognosis prediction of patients with gastric cancer on the basis of baseline and posttreatment features. PATIENTS AND METHODS: This single-center cohort study included patients with gastric adenocarcinoma treated with neoadjuvant chemotherapy from June 2009 to July 2015 in the Gastrointestinal Cancer Center of Peking University Cancer Hospital. Their clinicopathological data, pre-treatment and post-treatment computed tomography (CT) images, and pathological reports were retrieved and analyzed. Four prediction models were developed and validated using tenfold cross-validation, with death within 3 years as the outcome. Model discrimination was compared by the area under the curve (AUC). The final radiomic model was evaluated for calibration and clinical utility using Hosmer-Lemeshow tests and decision curve analysis. RESULTS: The study included 205 patients with gastric adenocarcinoma [166 (81%) male; mean age 59.9 (SD 10.3) years], with 71 (34.6%) deaths occurring within 3 years. The radiomic model alone demonstrated better discrimination than the pathological T stage (ypT) stage model alone (cross-validated AUC 0.598 versus 0.516, P = 0.009). The final radiomic model, which incorporated both radiomic and clinicopathological characteristics, had a significantly higher cross-validated AUC (0.769) than the ypT stage model (0.516), the radiomics alone model (0.598), and the ypT plus other clinicopathological characteristics model (0.738; all P < 0.05). Decision curve analysis confirmed the clinical utility of the final radiomic model. CONCLUSIONS: The developed radiomic model had good accuracy and could be used as a decision aid tool in clinical practice to differentiate prognosis of patients with gastric cancer.

A Biodegradable Janus Sponge for Negative Pressure Wound Therapy.

Negative pressure wound therapy (NPWT) is effective in repairing serious skin injury. The dressing used in the NPWT is important for wound healing. In this paper, we develop biodegradable amphiphilic polyurethanes (PUs) and fabricate the PUs into sponges as wound dressings (Bi@e) with Janus pore architectures for NPWT. The Bi@e is adaptive to all the stages of the wound healing process. The Janus Bi@e sponge consists of two layers: the dense hydrophobic upper layer with small pores provides protection and support during negative pressure drainage, and the loose hydrophilic lower layer with large pores absorbs large amounts of wound exudate and maintains a moist environment. Additionally, antibacterial agent silver sulfadiazine (SSD) is loaded into the sponge against Escherichia coli and Staphylococcus aureus with a concentration of 0.50 wt%. The Janus sponge exhibits a super absorbent capacity of 19.53 times its own water weight and remarkable resistance to compression. In a rat skin defect model, the Janus Bi@e sponge not only prevents the conglutination between regenerative skin and dressing but also accelerates wound healing compared to commercially available NPWT dressing. The Janus Bi@e sponge is a promising dressing for the NPWT.

CT assessed morphological features can predict higher mitotic index in gastric gastrointestinal stromal tumors.

OBJECTIVES: To investigate the correlation of the mitotic index (MI) of 1-5 cm gastric gastrointestinal stromal tumors (gGISTs) with CT-identified morphological and first-order radiomics features, incorporating subgroup analysis based on tumor size. METHODS: We enrolled 344 patients across four institutions, each pathologically diagnosed with 1-5 cm gGISTs and undergoing preoperative contrast-enhanced CT scans. Univariate and multivariate analyses were performed to investigate the independent CT morphological high-risk features of MI. Lesions were categorized into four subgroups based on their pathological LD: 1-2 cm (n = 69), 2-3 cm (n = 96), 3-4 cm (n = 107), and 4-5 cm (n = 72). CT morphological high-risk features of MI were evaluated in each subgroup. In addition, first-order radiomics features were extracted on CT images of the venous phase, and the association between these features and MI was investigated. RESULTS: Tumor size (p = 0.04, odds ratio, 1.41; 95% confidence interval: 1.01-1.96) and invasive margin (p < 0.01, odds ratio, 4.55; 95% confidence interval: 1.77-11.73) emerged as independent high-risk features for MI > 5 of 1-5 cm gGISTs from multivariate analysis. In the subgroup analysis, the invasive margin was correlated with MI > 5 in 3-4 cm and 4-5 cm gGISTs (p = 0.02, p = 0.03), and potentially correlated with MI > 5 in 2-3 cm gGISTs (p = 0.07). The energy was the sole first-order radiomics feature significantly correlated with gGISTs of MI > 5, displaying a strong correlation with CT-detected tumor size (Pearson's ρ = 0.85, p < 0.01). CONCLUSIONS: The invasive margin stands out as the sole independent CT morphological high-risk feature for 1-5 cm gGISTs after tumor size-based subgroup analysis, overshadowing intratumoral morphological characteristics and first-order radiomics features. KEY POINTS: Question How can accurate preoperative risk stratification of gGISTs be achieved to support treatment decision-making? Findings Invasive margins may serve as a reliable marker for risk prediction in gGISTs up to 5 cm, rather than surface ulceration, irregular shape, necrosis, or heterogeneous enhancement. Clinical relevance For gGISTs measuring up to 5 cm, preoperative prediction of the metastatic risk could help select patients who could be treated by endoscopic resection, thereby avoiding overtreatment.

Carbene-Catalyzed [4+2] Cycloaddition of Cyclobutenones and Isatins for Quick Access to Chiral Chlorine-Containing Spirocyclic δ-Lactones.

Here we report a carbene-catalyzed enantio- and diastereoselective [4+2] cycloaddition reaction of cyclobutenones with isatins for the quick and efficient synthesis of spirocyclic δ-lactones bearing a chiral chlorine. A broad range of substrates with various substitution patterns proceed smoothly in this reaction, with the spirooxindole δ-lactone products afforded in generally good to excellent yields and optical purities under mild reaction conditions.

Liquid biopsy in prostate cancer: A novel dual biomarker analysis approach integrating circulating tumor cells and circulating tumor DNA data.

This study aimed to explore the potential of liquid biopsy as a diagnostic tool by integrating two key biomarkers, Circulating Tumor Cells (CTCs) and Circulating Tumor DNA (ctDNA), and to enhance the detection fidelity of prostate cancer. A dual biomarker analysis approach was employed to synergize the sensitivities of CTCs and ctDNA. Various genetic mutations of ctDNA and tissues were scrutinized, investigating their prevalence, co-existence, and mutual exclusivity. The findings uncovered a more intricate mutation landscape than previously anticipated, indicating a complex interplay between cellular and genetic aberrations in prostate cancer. Through harnessing the combined power of CTCs and ctDNA, our dual biomarker approach provides a more comprehensive understanding of prostate cancer genetics. This has the potential to revolutionize early detection and guide personalized therapeutic interventions.

Ion current rectification properties of non-Newtonian fluids in conical nanochannels.

Ionic current rectification generated by the geometric asymmetry of conical nanochannels has gradually attracted attention, but most studies have been limited to Newtonian fluids. In this study, the ionic current rectification characteristics in conical nanochannels filled with non-Newtonian fluids are investigated by numerical simulations. Electroosmotic flow and ion transport in Sisko fluids are solved using the Poisson-Nernst-Planck equations and the Navier-Stokes equations. The effects of the Debye parameter, power-law indexes and applied voltage on the ionic current, axial potential, ion concentration, radial velocity and rectification ratio in the nanopores are investigated. When κRt = 1, the current rectification ratio increases with the increase of the power-law index. However, when κRt = 6, the current rectification ratio first increases and then decreases with the increase of the power law index, reaching the maximum value at n = 1.0. These findings have positive implications for the construction of some nanodevices such as nanofluidic diodes.

Novel 1,3,4-oxadiazole hybrids of 3-n-butylphthalide derivatives as potential anti-ischemic stroke agents.

In continuation of our program to search for novel potential anti-ischemic stroke agents, a series of 1,3,4-oxadiazole and sulfoxide hybrids of phthalide derivatives was designed and synthesized in this study to evaluate their anti-ischemic stroke activity. Among them, compounds 5b, 5d, 5 l, and 5 m exhibited excellent inhibitory effects on platelet aggregation induced by adenosine diphosphate (ADP) and arachidonic acid (AA). In particular, compound 5b possessed considerable antithrombotic activity in animal models, as demonstrated by the effective alleviation of carrageenan-induced and FeCl3-induced thrombosis in tail and carotid arteries, respectively. Notably, intraperitoneal administration of compound 5b could better protect the brain from injury caused by ischemia/reperfusion in rats compared with precursor 3-n-butylphthalide. Further pharmacokinetics, liver microsomal stability, and PAMPA-BBB assays also indicated that compound 5b had relatively high bioavailability, metabolic stability, and BBB permeability. Moreover, compound 5b showed a safety profile that was superior to the clinical drugs clopidogrel, aspirin, and 3-n-butylphthalide in the mouse-tail bleeding assay. Finally, molecular docking predicted that the potential target of the antiplatelet aggregation activity of compound 5b was P2Y12 receptor. This research provides a novel candidate compound for the treatment of ischemic stroke.

Scutellarein derivatives with histamine H3 receptor antagonism and cholinesterase inhibitory potency as multi target-directed ligands for possible Alzheimer's disease therapy.

A series of scutellarein 7-l-amino acid carbamate-4'-cycloalkylamine propyl ether conjugates were designed and synthesized for the first time as multifunctional agents for Alzheimer's disease (AD) therapy. The designed compounds exhibited more balanced and effective multi-target potency. Among them, compound 11l, l-Valine carbamate derivative of scutellarein cycloheptylamine ether, exhibited the most potent inhibition of electric eel AChE enzymes and human AChE enzymes, with an IC50 values of 7.04 µM and 9.73 µM, respectively. Moreover, 11l exhibited more potent H3R antagonistic activities than clobenpropit, with an IC50 value of 1.09 nM. Compound 11l not only displayed excellent inhibition of self- and Cu2+-induced Aß1-42 aggregation (95.48 % and 88.63 % inhibition, respectively) but also induced the disassembly of self- and Cu2+-induced Aß fibrils (80.16 % and 89.30 % disaggregation, respectively). Moreover, 11l significantly reduced tau protein hyperphosphorylation induced by Aß25-35. It exhibited effective antioxidant activity and neuroprotective potency, and inhibited RSL3-induced PC12 cell ferroptosis. Assays of hCMEC/D3 and hPepT1-MDCK cell line permeability indicated that 11l would have optimal blood-brain barrier permeability and intestinal absorption characteristics. In addition, in vivo studies revealed that compound 11l significantly attenuated learning and memory impairment in an AD mouse model. Finally, a pharmacokinetic characterization of 11l indicated favorable druggability and pharmacokinetic properties. Taken together, our results suggest that 11l is a potential candidate for AD treatment and merits further investigation.

Activation of the PERK-CHOP signaling pathway during endoplasmic reticulum stress contributes to olanzapine-induced dyslipidemia.

Olanzapine (OLZ) is a widely prescribed antipsychotic drug with a relatively ideal effect in the treatment of schizophrenia (SCZ). However, its severe metabolic side effects often deteriorate clinical therapeutic compliance and mental rehabilitation. The peripheral mechanism of OLZ-induced metabolic disorders remains abstruse for its muti-target activities. Endoplasmic reticulum (ER) stress is implicated in cellular energy metabolism and the progression of psychiatric disorders. In this study, we investigated the role of ER stress in the development of OLZ-induced dyslipidemia. A cohort of 146 SCZ patients receiving OLZ monotherapy was recruited, and blood samples and clinical data were collected at baseline, and in the 4th week, 12th week, and 24th week of the treatment. This case-control study revealed that OLZ treatment significantly elevated serum levels of endoplasmic reticulum (ER) stress markers GRP78, ATF4, and CHOP in SCZ patients with dyslipidemia. In HepG2 cells, treatment with OLZ (25, 50 µM) dose-dependently enhanced hepatic de novo lipogenesis accompanied by SREBPs activation, and simultaneously triggered ER stress. Inhibition of ER stress by tauroursodeoxycholate (TUDCA) and 4-phenyl butyric acid (4-PBA) attenuated OLZ-induced lipid dysregulation in vitro and in vivo. Moreover, we demonstrated that activation of PERK-CHOP signaling during ER stress was a major contributor to OLZ-triggered abnormal lipid metabolism in the liver, suggesting that PERK could be a potential target for ameliorating the development of OLZ-mediated lipid dysfunction. Taken together, ER stress inhibitors could be a potentially effective intervention against OLZ-induced dyslipidemia in SCZ.

Synthesis and antifungal activities of small molecule arylthiazolamine derivatives.

Developing new fungicides to compensate for the deficiencies of existing fungicides resistance in phytopathogenic fungi is a research hotspot in the field of pesticides. Aiming to discover novel template small molecules with excellent antifungal activity, thirty-eight arylthiazolamine derivatives were synthesized through bromination, cyclization, halogenation, and acylation reactions. The synthesized compounds were screened for antifungal activity against ten typical fungal pathogens, and some halogenated arylthiazolamines and amides exhibited excellent broad-spectrum antifungal activity, especially compounds 4m (3.96-47.76 µg/mL), 5k (0.10-7.70 µg/mL) and 5n (2.08-11.21 µg/mL). Among them, compound 5k provided comparable protection and curative effects to chloroticonil and boscalid against B. dothidea and V. mali infection in apple and apple tree branches, respectively, and it could exert antifungal effects by inhibiting the differentiation of mycelium spores, spore germination, and bud tube growth. This study provides high-efficiency and inexpensive candidate compounds for managing of diseases caused by plant pathogenic fungi.

Associations between UGT1A1, SLCO1B1, SLCO1B3, BLVRA and HMOX1 polymorphisms and susceptibility to neonatal severe hyperbilirubinemia in Chinese Han population.

BACKGROUND: Severe neonatal hyperbilirubinemia could lead to kernicterus and neonatal death. This study aimed to analyze the association between single nucleotide polymorphisms in genes involved in bilirubin metabolism and the incidence of severe hyperbilirubinemia. METHODS: A total of 144 neonates with severe hyperbilirubinemia and 50 neonates without or mild hyperbilirubinemia were enrolled in 3 institutions between 2019 and 2020. Twelve polymorphisms of 5 genes (UGT1A1, SLCO1B1, SLCO1B3, BLVRA, and HMOX1) were analyzed by PCR amplification of genomic DNA. Genotyping was performed using an improved multiplex ligation detection reaction technique based on ligase detection reaction. RESULTS: The frequencies of the A allele in UGT1A1-rs4148323 and the C allele in SLCO1B3-rs2417940 in the severe hyperbilirubinemia group (30.2% and 90.6%, respectively) were significantly higher than those in the controls (30.2% vs.13.0%, 90.6% vs. 78.0%, respectively, both p < 0.05). Haplotype analysis showed the ACG haplotype of UGT1A1 were associated with an increased hyperbilirubinemia risk (OR 3.122, p = 0.001), whereas the GCG haplotype was related to a reduced risk (OR 0.523, p = 0.018). CONCLUSION: The frequencies of the A allele in rs4148323 and the C allele in rs2417940 are highly associated with the incidence of severe hyperbilirubinemia in Chinese Han neonates. TRIAL REGISTRATION: Trial registration number:ChiCTR1800020424; Date of registration:2018-12-29.

FOXM1 mediates methotrexate resistance in osteosarcoma cells by promoting autophagy.

Osteosarcoma (OS) is a primary bone cancer mostly found in adolescents and elderly individuals. The treatment of OS is still largely dependent on traditional chemotherapy. However, the high incidence of drug resistance remains one of the greatest impediments to limiting improvements in OS treatment. Recent findings have indicated that the transcription factor FOXM1 plays an important role in various cancer-related events, especially drug resistance. However, the possible role of FOXM1 in the resistance of OS to methotrexate (MTX) remains to be explored. Here, we find that FOXM1, which confers resistance to MTX, is highly expressed in OS tissues and MTX-resistant cells. FOXM1 overexpression promotes MTX resistance by enhancing autophagy in an HMMR/ATG7-dependent manner. Importantly, silencing of FOXM1 or inhibiting autophagy reverses drug resistance. These findings demonstrate a new mechanism for FOXM1-induced MTX resistance and provide a promising target for improving OS chemotherapy outcomes.

An evidence review of face masks against COVID-19.

The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.