Air Change Rate and SARS-CoV-2 Exposure in Hospitals and Residences: A Meta-Analysis.

As SARS-CoV-2 swept across the globe, increased ventilation and implementation of air cleaning were emphasized by the US CDC and WHO as important strategies to reduce the risk of inhalation exposure to the virus. To assess whether higher ventilation and air cleaning rates lead to lower exposure risk to SARS-CoV-2, 1274 manuscripts published between April 2020 and September 2022 were screened using key words "airborne SARS-CoV-2 or "SARS-CoV-2 aerosol". Ninety-three studies involved air sampling at locations with known sources (hospitals and residences) were selected and associated data were compiled. Two metrics were used to assess exposure risk: SARS-CoV-2 concentration and SARS-CoV-2 detection rate in air samples. Locations were categorized by type (hospital or residence) and proximity to the sampling location housing the isolated/quarantined patient (primary or secondary). The results showed that hospital wards had lower airborne virus concentrations than residential isolation rooms. A negative correlation was found between airborne virus concentrations in primary-occupancy areas and air changes per hour (ACH). In hospital settings, sample positivity rates were significantly reduced in secondary-occupancy areas compared to primary-occupancy areas, but they were similar across sampling locations in residential settings. ACH and sample positivity rates were negatively correlated, though the effect was diminished when ACH values exceeded 8. While limitations associated with diverse sampling protocols exist, data considered by this meta-analysis support the notion that higher ACH may reduce exposure risks to the virus in ambient air.

Detection and isolation of infectious SARS-CoV-2 omicron subvariants collected from residential settings.

Airborne transmission of infectious (viable) SARS-CoV-2 is increasingly accepted as the primary manner by which the virus is spread from person to person. Risk of exposure to airborne virus is higher in enclosed and poorly ventilated spaces. We present a study focused on air sampling within residences occupied by individuals with COVID-19. Air samplers (BioSpot-VIVAS, VIVAS, and BC-251) were positioned in primary- and secondary-occupancy regions in seven homes. Swab samples were collected from high-touch surfaces. Isolation of SARS-CoV-2 was attempted for samples with virus detectable by RT-qPCR. Viable virus was quantified by plaque assay, and complete virus genome sequences were obtained for selected samples from each sampling day. SARS-CoV-2 was detected in 24 of 125 samples (19.2%) by RT-qPCR and isolated from 14 (11.2%) in cell cultures. It was detected in 80.9% (17/21) and cultured from 61.9% (13/21) of air samples collected using water condensation samplers, compared to swab samples which had a RT-qPCR detection rate of 10.5% (4/38) and virus isolation rate of 2.63% (1/38). No statistically significant differences existed in the likelihood of virus detection by RT-qPCR or amount of infectious virus in the air between areas of primary and secondary occupancy within residences. Our work provides information about the presence of SARS-CoV-2 in the air within homes of individuals with COVID-19. Information herein can help individuals make informed decisions about personal exposure risks when sharing indoor spaces with infected individuals isolating at home and further inform health departments and the public about SARS-CoV-2 exposure risks within residences.

Single-Cell Analysis Reveals Malignant Cells Reshape the Cellular Landscape and Foster an Immunosuppressive Microenvironment of Extranodal NK/T-Cell Lymphoma.

Extranodal natural killer/T-cell lymphoma (NKTCL) is an aggressive type of lymphoma associated with Epstein-Barr virus (EBV) and characterized by heterogeneous tumor behaviors. To better understand the origins of the heterogeneity, this study utilizes single-cell RNA sequencing (scRNA-seq) analysis to profile the tumor microenvironment (TME) of NKTCL at the single-cell level. Together with in vitro and in vivo models, the study identifies a subset of LMP1+ malignant NK cells contributing to the tumorigenesis and development of heterogeneous malignant cells in NKTCL. Furthermore, malignant NK cells interact with various immunocytes via chemokines and their receptors, secrete substantial DPP4 that impairs the chemotaxis of immunocytes and regulates their infiltration. They also exhibit an immunosuppressive effect on T cells, which is further boosted by LMP1. Moreover, high transcription of EBV-encoded genes and low infiltration of tumor-associated macrophages (TAMs) are favorable prognostic indicators for NKTCL in multiple patient cohorts. This study for the first time deciphers the heterogeneous composition of NKTCL TME at single-cell resolution, highlighting the crucial role of malignant NK cells with EBV-encoded LMP1 in reshaping the cellular landscape and fostering an immunosuppressive microenvironment. These findings provide insights into understanding the pathogenic mechanisms of NKTCL and developing novel therapeutic strategies against NKTCL.

Characteristics and classification of first primary cancer patients with second primary cancer: a population-based cohort study.

Cancer survivors have an increased risk of developing subsequent primary tumors. However, the characteristics of first primary cancers (FPCs) with various types of second primary cancers (SPCs) are poorly understood, which hinders screening strategies. We analyzed data from 1,893,258 patients from the Surveillance, Epidemiology, and End Results (SEER) database to characterize and classify of FPC patients with subsequent SPCs at the pan-cancer level. In total, 3% of patients had SPC, with varied incidence rates observed depending on the types of FPC. Their onset patterns of SPC and diversity of SPC varied. Based on the diversity of the high-incidence sites of SPC, we classified FPCs into two categories: FPCs that require whole-body screening and those that need screening of particular body parts. Moreover, according to the different timing of high incidence of SPCs, our system classifies FPCs into two subtypes: FPCs that require long-term monitoring for the occurrence of SPCs and those that require screening at specific time points for SPCs. Furthermore, we identified 11 anatomical sites where over half of FPC types are prone to SPC occurrence at these locations. The risk factors for SPC occurrence in different FPC types and prognostic factors were also elucidated. Overall, we characterize and classify of FPC patients with subsequent SPCs at the pan-cancer level, which can guide the development of distinct screening strategies for each FPC type.

Targeting small GTPases: emerging grasps on previously untamable targets, pioneered by KRAS.

Small GTPases including Ras, Rho, Rab, Arf, and Ran are omnipresent molecular switches in regulating key cellular functions. Their dysregulation is a therapeutic target for tumors, neurodegeneration, cardiomyopathies, and infection. However, small GTPases have been historically recognized as "undruggable". Targeting KRAS, one of the most frequently mutated oncogenes, has only come into reality in the last decade due to the development of breakthrough strategies such as fragment-based screening, covalent ligands, macromolecule inhibitors, and PROTACs. Two KRASG12C covalent inhibitors have obtained accelerated approval for treating KRASG12C mutant lung cancer, and allele-specific hotspot mutations on G12D/S/R have been demonstrated as viable targets. New methods of targeting KRAS are quickly evolving, including transcription, immunogenic neoepitopes, and combinatory targeting with immunotherapy. Nevertheless, the vast majority of small GTPases and hotspot mutations remain elusive, and clinical resistance to G12C inhibitors poses new challenges. In this article, we summarize diversified biological functions, shared structural properties, and complex regulatory mechanisms of small GTPases and their relationships with human diseases. Furthermore, we review the status of drug discovery for targeting small GTPases and the most recent strategic progress focused on targeting KRAS. The discovery of new regulatory mechanisms and development of targeting approaches will together promote drug discovery for small GTPases.

Pan-cancer analysis identifies DDX56 as a prognostic biomarker associated with immune infiltration and drug sensitivity.

DDX56, a member of the RNA helicase family, is upregulated in colon adenocarcinoma, lung squamous cell carcinoma, and osteosarcoma. However, the relationships between DDX56 and other tumors are not clear, and the molecular mechanism of its action is not fully understood. Here, we explore the biological functions of DDX56 in 31 solid tumors and clarify that DDX56 can promote oncogenesis and progression in multiple tumor types based on multi-omics data. Bioinformatics analysis revealed that the cancer-promoting effects of DDX56 were achieved by facilitating tumor cell proliferation, inhibiting apoptosis, inducing drug resistance, and influencing immune cell infiltration. Furthermore, we found that copy number alterations and low DNA methylation of DDX56 were likely to be related to aberrantly high DDX56 expression. Our results suggest that DDX56 is a potential pan-cancer biomarker that could be used to predict survival and response to therapy, as well as a potential novel therapeutic target. We validated some of our results and illustrated their reliability using CRISPR Screens data. In conclusion, our results clarify the role of DDX56 in the occurrence and development of multiple cancers and provide insight into the molecular mechanisms involved in the process of pathogenesis, indicating a direction for future research on DDX56 in cancers.

Active projection nonlinear γ correction method for fringe projection profilometry.

In fringe projection profilometry (FPP), the luminance nonlinearity generated by the superimposed γ effect of the projector and camera can lead to distortion of the intensity of the sinusoidal phase-shift fringe, resulting in a reduction of measurement precision and resolution. Traditional phase error compensation and γ-correction methods need to focus on the projector's optimal performance. However, commercial projectors often have huge apertures and are, therefore, unable to project a perfectly focused sinusoidal fringe image. This paper proposes an easy-to-implement active projection error correction method with high precision that is insensitive to projector defocus. After calibrating the projector to establish the nonlinear γ-response model of the optical measurement system, inverse γ compensation is performed. By generating and projecting a set of precorrected sinusoidal fringes, the camera can capture the high-quality sinusoidal fringe image and decrease the phase measurement error caused by the nonlinear γ effect of the FPP system. Computer simulations and experiments verify the effectiveness and feasibility of the proposed method for estimating and correcting the nonlinear γ distortion of the FPP system. The experimental results show that using the proposed active projection method to compensate for the error of the three-step phase-shift algorithm can achieve a high-precision measurement, and the influence of the system's nonlinear γ effect on the measurement accuracy is significantly suppressed.

Tumor microenvironment-activated single-atom platinum nanozyme with H2O2 self-supplement and O2-evolving for tumor-specific cascade catalysis chemodynamic and chemoradiotherapy.

Nanozyme-based tumor collaborative catalytic therapy has attracted a great deal of attention in recent years. However, their cooperative outcome remains a great challenge due to the unique characteristics of tumor microenvironment (TME), such as insufficient endogenous hydrogen peroxide (H2O2) level, hypoxia, and overexpressed intracellular glutathione (GSH). Methods: Herein, a TME-activated atomic-level engineered PtN4C single-atom nanozyme (PtN4C-SAzyme) is fabricated to induce the "butterfly effect" of reactive oxygen species (ROS) through facilitating intracellular H2O2 cycle accumulation and GSH deprivation as well as X-ray deposition for ROS-involving CDT and O2-dependent chemoradiotherapy. Results: In the paradigm, the SAzyme could boost substantial ∙OH generation by their admirable peroxidase-like activity as well as X-ray deposition capacity. Simultaneously, O2 self-sufficiency, GSH elimination and elevated Pt2+ release can be achieved through the self-cyclic valence alteration of Pt (IV) and Pt (II) for alleviating tumor hypoxia, overwhelming the anti-oxidation defense effect and overcoming drug-resistance. More importantly, the PtN4C-SAzyme could also convert O2·- into H2O2 by their superior superoxide dismutase-like activity and achieve the sustainable replenishment of endogenous H2O2, and H2O2 can further react with the PtN4C-SAzyme for realizing the cyclic accumulation of ∙OH and O2 at tumor site, thereby generating a "key" to unlock the multi enzymes-like properties of SAzymes for tumor-specific self-reinforcing CDT and chemoradiotherapy. Conclusions: This work not only provides a promising TME-activated SAzyme-based paradigm with H2O2 self-supplement and O2-evolving capacity for intensive CDT and chemoradiotherapy but also opens new horizons for the construction and tumor catalytic therapy of other SAzymes.

A Biofilm Microenvironment-Activated Single-Atom Iron Nanozyme with NIR-Controllable Nanocatalytic Activities for Synergetic Bacteria-Infected Wound Therapy.

Biofilm microenvironment (BME)-activated antimicrobial agents display great potential for improved biofilm-related infection therapy because of their superior specificities and sensitivities, effective eliminations, and minimal side effects. Herein, BME-activated Fe-doped polydiaminopyridine nanofusiform-mediated single-atom nanozyme (FePN SAzyme) is presented for photothermal/chemodynamic synergetic bacteria-infected wound therapy. The photothermal therapy (PTT) function of SAzyme can be specifically initiated by the high level of H2 O2 and further accelerated through mild acid within the inflammatory environment through "two-step rocket launching-like" process. Additionally, the enhanced chemodynamic therapy (CDT) for the FePN SAzyme can also be endowed by producing hydroxyl radicals through reacting with H2 O2 and consuming glutathione (GSH) of the BME, thereby contributing to more efficient synergistic therapeutic effect. Meanwhile, FePN SAzyme could catalyze biofilm-overexpressed H2 O2 decomposing into O2 and overcome the hypoxia of biofilm, which significantly enhances the susceptibility of biofilm and increases the synergistic efficacy. Most importantly, the synergistic therapy of bacterial-induced infection diseases can be switched on by the internal and external stimuli simultaneously, resulting in minimal nonspecific damage to healthy tissue. These remarkable characteristics of FePN SAzyme not only develop an innovative strategy for the BME-activated combination therapy but also open a new avenue to explore other nanozyme-involved nanoplatforms for bacterial biofilm infections.

Fe-Based Single-Atom Nanozyme with Superior Peroxidase-Mimicking Activity for Enhanced Ultrasensitive Biosensing.

Nanomaterials with intrinsic enzyme-mimicking characteristics, refered to as nanozymes, have become a hot research topic owing to their unique advantages of comparative low cost, high stability and large-scale preparation. Among them, Single-atom nanozymes (SAzymes), as novel nanozymes with abundant atomically dispersed active sites, have caused specific attention in the development of nanozymes for their remarkable catalytic activities, maximum atomic utilization and excellent selectivity, the homogeneous catalytic sites and clear catalytic mechanisms. Herein, a novel single-atom nanozyme based on Fe(III)-doped polydiaminopyridine nanofusiforms (Fe-PDAP SAzyme) was successfully proposed via facile oxidation polymerization strategy. With well-defined coordination structure and abundant Fe-Nx active sites similar to natural metalloproteases, the Fe-PDAP SAzyme exhibits superior peroxidase-like activity by efficiently decomposing H2O2 for hydroxyl radical (.OH) species formation. Based on their superior peroxidase-like activity, colorimetric biosensing of H2O2 and glucose in vitro was performed by using a typical 3,3,5,5-tetramethylbenzidine through a multienzyme biocatalytic cascade platform, exhibiting the superior specificity and sensitivity. This work not only provides a novel promising SAzyme-based biosensor but also paves an avenue for evaluating enzyme activity and broadens the application of other nanozyme-based biosensors in the fields of biomedical diagnosis.

Bacteria responsive polyoxometalates nanocluster strategy to regulate biofilm microenvironments for enhanced synergetic antibiofilm activity and wound healing.

Backgroud: Nowadays, biofilms that are generated as a result of antibiotic abuse cause serious threats to global public health. Such films are the primary factor that contributes to the failure of antimicrobial treatment. This is due to the fact that the films prevent antibiotic infiltration, escape from innate immune attacks by phagocytes and consequently generate bacterial resistance. Therefore, exploiting novel antibacterial agents or strategies is extremely urgent. Methods: Herein, we report a rational construction of a novel biofilm microenvironment (BME)-responsive antibacterial platform that is based on tungsten (W)-polyoxometalate clusters (POMs) to achieve efficient bactericidal effects. Results: On one hand, the acidity and reducibility of a BME could lead to the self-assembly of POMs to produce large aggregates, which favor biofilm accumulation and enhance photothermal conversion under near-infrared (NIR) light irradiation. On the other hand, reduced POM aggregates with BME-induced photothermal-enhanced efficiency also exhibit surprisingly high peroxidase-like activity in the catalysis of bacterial endogenous hydrogen peroxide (H2O2) to produce abundant reactive oxygen species (ROS). This enhances biofilm elimination and favors antibacterial effects. Most importantly, reduced POMs exhibit the optimal peroxidase-like activity in an acidic BME. Conclusion: Therefore, in addition to providing a prospective antibacterial agent, intelligent acid/reductive dual-responsive POMs will establish a new representative paradigm for the areas of healthcare with minimal side effects.