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Polymers containing heavy elements exhibit high refractive indices and excellent radiation shielding properties. However, a major challenge is their tendency to absorb visible light, leading to coloration and reduced transparency. To address this fundamental issue, we designed a bismuth-containing monomer that can undergo radical polymerization, in which the binding position of the polymerizable vinyl group was optimized, thereby introducing a novel molecular design that suppresses visible-light absorption. The resulting monomer underwent both thermal radical polymerization and photopolymerization, yielding a colorless, transparent, and self-supporting film that exhibited a high refractive index (nD) of 1.72 and excellent X-ray shielding properties equivalent to 1.67 μm-Al/μm-polymer. This study establishes a new strategy for the molecular design of high-refractive-index transparent materials containing heavy elements and significantly expands their applications in optical and X-ray shielding materials.

Infectious viral aerosols outside primary containment represent a profound yet undercharacterized occupational biohazard in microbiological environments. While the role of viral aerosols in laboratory-acquired infections is widely acknowledged, quantitative data on the concentration and size distribution of viral aerosols generated during common laboratory workflows remain limited. This study addresses these gaps by using a controlled chamber to characterize the generation of aerosols containing either a physical tracer, sodium fluorescein, or a viral pathogen surrogate, bacteriophage MS2. By integrating aerodynamic particle sizing with cascade impaction and filtered collection, we quantified the mass, number, and infectivity of aerosols emitted during both routine laboratory procedures and simulated accidental releases. These results reveal that every evaluated action generated measurable aerosols spanning multiple particle sizes. Importantly, all MS2-based actions produced infectious aerosols within the respirable size fraction, confirming that routine benchtop pipetting actions yield viral aerosols. These data provide an empirical foundation for evidence-based risk assessments. Laboratory-acquired viral infections have occurred following routine laboratory procedures in which no distinct accident is recorded, suggesting unrecognized release and inhalation of infectious virus. This research provides a quantitative analysis of these aerosols using a non-pathogenic viral surrogate, MS2, to model viral pathogens. We demonstrate that common laboratory tasks, such as pipetting or handling culture plates, generate respirable infectious aerosols that can bypass standard precautions when outside primary containment. By defining the size and infectious load of these aerosols, this work enables biosafety professionals to transition from qualitative assumptions to data-driven safety protocols, ultimately protecting the personnel responsible for viral pathogen research.

The mitochondrial genome of plants contains an open reading frame, orfx, which encodes a protein classified as very rare and which has so far escaped mass spectrometric detection. The protein resembles the c-subunit of bacterial twin-arginine-motif-dependent protein translocases (TatC). Using native prefractionation of mitochondrial protein complexes from Arabidopsis and trapped-ion mobility spectrometry (TIMS) time-of-flight mass spectrometry, we report the identification of three peptides of the orfx protein. Our experimental approach was used to trace the native forms of the protein and show that it is present in protein complexes in the size range of 450-530 kDa, which also contain TatB. We suggest that mitochondrial TatBC complexes in plants may bind to late assembly intermediates of respiratory chain complex III.

Quorum sensing (QS) enables microorganisms-including bacteria, eukaryotes, and viruses-to coordinate collective behaviors in response to population density. Despite their ecological and evolutionary significance, QS mechanisms in Archaea remain poorly characterized. The halophilic archaeon Haloferax volcanii provides a model for archaeal QS, transitioning from motile rods to non-motile disks in a density-dependent response to a secreted disk-forming signal (DFS). To identify components of the DFS regulatory network, we screened for spontaneous mutants that retained motility in DFS-containing soft-agar medium. One candidate, HVO_1357, encodes a predicted response regulator located adjacent to a histidine kinase (HVO_1356) and a second response regulator (HVO_1358), consistent with an extended two-component regulatory system (TCS). Based on our results, these genes encode quorum-sensing-associated regulators (Qar); therefore, we propose renaming them to qarA (HVO_1357), qarB (HVO_1356), and qarC (HVO_1358). Deletion of qarA enabled cells to swim on DFS-containing soft-agar plates and conferred hypermotility on standard soft-agar media; however, these phenotypes were not due to changes in motility-related parameters, but a reduced sensitivity to DFS for induction of the non-motile, disk-shaped state. In contrast, ΔqarB and ΔqarC strains were non-motile and exhibited premature disk formation during normal growth. Suppressor mutations restoring motility to ΔqarB and ΔqarC mapped exclusively to qarA, and epistasis analysis indicated QarA as the central regulator of this system. Phosphoablative variants of QarA, QarB, and QarC failed to complement their respective deletion strains, supporting QarABC as a TCS. Transcriptomic analyses revealed that qarA deletion leads to upregulation of genes involved in motility and rod-shape formation. Together, these findings reveal qarABC as a DFS-responsive regulatory module and represent the first TCS in archaea shown to control QS-dependent behavior.IMPORTANCEArchaea are ubiquitous and play key roles across diverse ecosystems-including human microbiomes-yet little is known about how they communicate with one another and with other organisms, or how these interactions shape their ecological impact. Such intercellular communication, including quorum sensing (QS), allows microorganisms to coordinate behaviors critical for survival, adaptation, and community organization. In this study, we identify the first archaeal two-component regulatory system that is involved in QS-dependent regulation, providing a foundation for understanding how organisms in this domain sense and respond to population cues. By revealing a previously unknown aspect of archaeal biology, this work represents an important step toward understanding how archaeal communication shapes both their physiology and their interactions within complex microbial communities.

Based on density functional theory (DFT), this study investigated the interfacial interactions between pristine graphene (Gr), Gr with single-vacancy (SV), double-vacancy (DV), and Stone-Wales (SW) defects, as well as graphene oxide (GO) modified with different oxygen-containing functional groups, and representative units of calcium silicate hydrate (C-S-H) gel. The results show that the adsorption strength of Si(OH)4 on pristine Gr/GO surfaces is mainly controlled by the polarity of the functional groups, following the order of GO-COOH > GO-OH > GO-O > Gr. The SW defect can enhance the adsorption on Gr and GO-OH, but weakens the short-range interaction between GO-COOH and Si(OH)4. For negatively charged SiO(OH)3-, the SV defect can significantly promote interfacial charge redistribution. The adsorption energy of GO-OH-SV reaches -1.907 eV, accompanied by proton transfer and local structural reconstruction. The introduction of Ca2+ and OH- can further improve adsorption stability through coordination bridging, charge compensation, and the synergistic effect between defects and functional groups. Among them, the adsorption energy of Si(OH)4 on Gr-DV decreases to -3.902 eV, while that of SiO(OH)3- on GO-O-SV decreases to -4.974 eV. The interaction between pristine Gr and the silicate chain is mainly characterized by weak van der Waals interactions, whereas hydroxyl and carboxyl groups can form specific bonding with the dangling oxygen atoms of the silicate chain through active hydrogen atoms and enhance charge transfer. In the Ca2+/OH- environment, oxygen-containing functional groups and defect sites jointly construct multiple adsorption centers, further strengthening the interfacial bonding between Gr/GO and C-S-H gel units. Density functional theory (DFT) calculations were carried out using the CASTEP module in Materials Studio software. The GGA-PBE functional, ultrasoft pseudopotential, DFT-D dispersion correction, and Monkhorst-Pack k-point sampling were used for geometry optimization and energy calculations. Adsorption energy, formation energy, and charge density difference were calculated to evaluate the interaction between Gr/GO and C-S-H gel units.

The evolution of gene regulation is a major source of evolutionary adaptation and innovation, particularly when organisms encounter new or changing environments. Central to this process is the emergence of new transcription factor binding sites (TFBSs). Adaptive landscapes provide a powerful framework to study such emergence by linking regulatory DNA sequences to their transcriptional outputs. Although several landscapes have been characterized for DNA, RNA, and proteins, large-scale in vivo adaptive landscapes for bacterial TFBSs remain scarce. Here, we address this gap by experimentally mapping the first comprehensive in vivo regulatory landscapes for three global transcription factors in Escherichia coli: cAMP receptor protein, Fis, and IHF. Using a massively parallel reporter assay, we quantify the regulation strength of more than 30,000 TFBS variants for each factor, and reconstruct their adaptive landscapes. All three landscapes are highly rugged and exhibit pervasive epistasis, with thousands of local peaks distributed broadly across sequence space. This ruggedness contrasts sharply with the much smoother TFBS landscapes of eukaryotes. It suggests greater constraints on the evolution of prokaryotic gene regulation. Nonetheless, evolutionary simulations show that ~10% of evolving populations can reach a peak of strong regulation, a proportion that is significantly greater than in comparable random landscapes. Adaptive evolution starting from the same DNA sequence can attain different high peaks, and some peaks are reached more frequently than others. Together, our results show that de novo adaptive evolution of new gene regulation in bacteria is feasible, but subject to a blend of chance, historical contingency, and evolutionary biases. Organisms regulate the activity of their genes by turning them up or down at the right time and place. To do so, they use proteins called transcription factors, which bind to short stretches of DNA near a gene known as binding sites. How tightly a transcription factor binds to its binding site determines how strongly it regulates the gene's activity. As genomes evolve, mutations can create new binding sites, establishing entirely new connections within a cell's regulatory network. This is an important way in which organisms adapt to new environments during evolution. Yet the evolutionary steps that transform a random DNA sequence into a strong, functional binding site remain poorly understood, especially in bacteria. Mapping all possible binding sites for a transcription factor can reveal how readily evolution can generate new regulatory interactions. To test how evolution builds a strong binding site from scratch, Westmann, Goldbach and Wagner studied three major transcription factors in the bacterium Escherichia coli. For each transcription factor, they measured how strongly 30,000 different DNA sequences regulated a gene. To do this, they linked each sequence to a reporter gene that emitted light when activated and measured light emission in millions of cells. Using these data, the researchers constructed genetic landscapes, in which each DNA sequence occupied a position in the landscape and its height (or elevation, analogous to the height of a hill) represented the strength of gene regulation. Higher peaks, therefore, corresponded to greater gene activation, likely reflecting stronger transcription factor binding. All three landscapes contained thousands of distinct peaks, far more than comparable landscapes reported for animals and plants. Most of these peaks corresponded to only weak or moderate gene regulation, while peaks of strong regulation were rare. Despite this complexity, the analyses showed that evolution could still reach these rare, strong peaks through a series of small beneficial mutations more often than expected by chance. In other words, even highly complex landscapes can contain accessible routes to strong new binding sites. The work of Westmann et al. sheds light on how evolution creates and refines the simplest elements of gene regulation. These findings improve our understanding of how bacteria adapt to new environments, including the evolution of antibiotic resistance. In addition, the experimental and analytical approaches developed in this study provide valuable tools for researchers investigating the evolution of gene regulation and for those engineering synthetic genetic circuits in the laboratory.

Lithium-oxygen batteries hold great promise for next-generation energy storage systems due to their ultrahigh theoretical energy density. However, their development is hindered by high charging overpotentials and poor cycle stability. Herein, we propose a strategy of electronic structure regulation to design a Ru-modified Pt/C catalyst to address the key challenge of tuning the charge overpotential. Electron delocalization occurs from Ru to Pt in RuPt because of the electronegativity difference between Ru and Pt. The calculation results show that the 4d(Ru)-5d(Pt) orbital coupling regulates the d-band distribution of Pt sites in RuPt, including the moderate downshift of d-band center systematically across the Pt's five d-suborbitals and the broadening of d-band above the Fermi energy level. It weakens the adsorption strength towards oxygen-containing species and smooths the energy barriers of stepwise reactions during OER. Experimental results demonstrate that the Ru-Pt/C catalyst significantly reduces the overpotential by ∼1 V compared to Pt/C. Meanwhile, the Li-air battery also presents a low overpotential of 0.75 V after 100 cycles. This work advances the fundamental understanding of d-band regulation via engineering electronic structure in oxygen electrocatalysis and provides a practical pathway to mitigate overpotential-related challenges in high-energy-density metal-air batteries.

In this study, we developed PLSR models using both benchtop and portable NIR spectral data to quantitatively determine levothyroxine in commercial tablets containing 25-150 µg per tablet of the drug. The optimal PLSR model for benchtop NIR spectrometer was performed using a standard normal variate combined with the Savitzky-Golay first derivative and mean center data preprocessing with three latent factors. Model performance was defined by its R2 model, R2 Pearson, root mean square error of prediction (RMSEP), and bias. In this case, the values were 0.9852, 0.9585, 6.5814, and 1.6483, respectively. Contrarily, for portable NIR spectrometer, the optimal PLSR model was obtained from Savitzky-Golay first derivative combined with orthogonal signal correction and mean center data preprocessing with three latent factors. The performances of the R2 model, R2 Pearson, RMSEP, and bias were 0.9747, 0.9446, 7.2820, and -1.4825, respectively. These results highlight the potential of combining PLSR with NIR spectral data and, in particular, the potential of portable devices with performances comparable to those of benchtop devices for applications in pharmaceutical solid dosage forms with very low concentrations, while providing a greener and more sustainable alternative to solvent-based chromatographic analysis.

Per/polyfluoroalkyl substance (PFAS) exposure is a serious concern for firefighters, but the contribution of firefighting activities to overall PFAS body burden remains poorly understood. We hypothesized that overlooked novel PFASs may be elevated in firefighter serum after fire suppression activities. We analyzed paired "baseline" (annual checkup) and "postfire" (within 35 h of fire) serum from 33 members of the Tucson Fire Department using high-resolution mass spectrometry. We measured concentrations of 49 PFASs via targeted quantitation and detected 15 in >50% of samples. Concentrations of target analytes were not significantly different between baseline and postfire paired samples. However, branched PFOS isomers and linear PFHxS were significantly elevated compared to the general population. Suspect screening enabled the identification of 26 additional PFASs. Two tentatively identified phosphate-containing PFASs were significantly (p < 0.01) elevated postfire. These chemicals may be associated with exposure to fluorinated aryl phosphate flame retardants or their combustion transformation products during fire response. Several other novel PFASs were detected in baseline and postfire samples, including bis(trifluoromethylsulfonyl)imide (bis-FMeSI). The presence of novel PFASs in serum from firefighters highlights the need for more research into their occurrence in occupationally exposed groups and the general population, exposure sources, and toxicokinetics.

Glioblastoma (GBM) progression is driven by intricate interactions between neoplastic cells and immune populations within the tumor microenvironment (TME), yet the temporal organization of these processes remains insufficiently defined. While tumor-associated macrophages (TAMs), composed of microglia and monocyte-derived macrophages, constitute a major immune population in GBM, microglia play a prominent role in shaping local immunosuppressive niches, thereby limiting cytotoxic lymphocyte infiltration. However, static co-culture models constrain interrogation of dynamic tumor-immune signaling. We utilized a programmable multi-inlet microfluidic platform that allows sequential, order-specific introduction of immune cells into GBM constructs, enabling controlled interrogation of MG- and natural killer (NK)-mediated interactions under defined temporal conditions. Bulk transcriptomic profiling and single-cell analyses were used to characterize tumor- and immune-associated pathways elicited by distinct temporal configurations. In triculture constructs containing identical populations of GBM cells, microglia, and NK cells, MG-first delivery preferentially activated STAT3-associated immunoregulatory transcriptional programs, whereas NK-first delivery induced cytotoxic and interferon-related gene expression profiles. IL12A expression was selectively increased under NK-first conditions and correlated with immune-active GBM states in patient datasets. STAT3 inhibition reduced MG-associated suppression, increased IL12A expression, and enhanced the response to temozolomide. This programmable spheroid platform not only recapitulates hallmark features of the GBM immune microenvironment but also uncovers temporally regulated pathways arising from sequential cellular interactions. By enabling controlled reconstruction of dynamic tumor-immune signaling, this system offers a versatile strategy for mechanistic investigation and provides a foundation for evaluating immune-modulatory approaches and microenvironment-targeted interventions in GBM and other malignancies.

In this research, we derive equations for solving for the stationary points of the DLPNO-CCSD Lagrangian, in the t1-transformed formalism introduced earlier and as currently implemented in the Psi4 quantum chemistry software package. These lambda equations in the local pair natural orbital basis allow for the evaluation of CCSD(T)&#x39b; energetics with linear-scaling computational effort, also known as the asymmetric triples correction. This DLPNO-CCSD(T)&#x39b; method allows for accurate triples contributions to be computed for larger molecules, especially in cases that CCSD(T) is known to be insufficient, such as with multireference systems and bond-breaking systems. We showcase the accuracy of our code on reaction energies, barrier heights, and noncovalent interaction energies. Also showcased are the capabilities of our code by evaluating DLPNO-CCSD(T)&#x39b; energetics on large noncovalent dimers up to 112 atoms, as well as a rhodium catalyst complex containing 66 atoms.

Pancreatic ductal adenocarcinoma (PDAC) is largely resistant to immune checkpoint blockade (ICB) due to its highly immunosuppressive tumor microenvironment. How to switch the "immune-cold" microenvironment to "immune hot" one is a clinical unmet need. We recently generated a genetically engineered PDAC mouse model (KAR) by combining K-Ras mutation and AT-rich interactive domain-containing protein 1A (ARID1A) inactivation in the pancreas. Compared to the KPC (K-Ras mutation&#x2009;+&#x2009;p53 inactivation) tumors, KAR tumors express higher C-X-C chemokine receptor 2 (CXCR2) and have more CXCR2+ neutrophils infiltration. Our previous study demonstrated that activation of CXCR2 by its cognate ligands promotes proliferation and drug resistance in PDAC cells. In addition, increase in tumor-associated neutrophils and high neutrophil-to-lymphocyte ratio are associated with worse prognosis in PDAC patients. Here, we developed a monoclonal antibody against human CXCR2 (huCXCR2-Ab) and tested its therapeutic effect in cells and in animals. Treatment with huCXCR2-Ab inhibited IL-8-induced downstream signaling, and the proliferation of human PDAC cancer cells. In addition, huCXCR2-Ab suppressed PDAC growth in an orthotopic nude mouse model. We next developed a monoclonal antibody against mouse CXCR2 (muCXCR2-Ab) and investigated its immune regulatory effect in vivo. We showed that muCXCR2-Ab reduced tumor burden, increased CD8&#x207a; T-cell infiltration, and decreased immunosuppressive neutrophils in the KAR mice. Moreover, muCXCR2-Ab augments the therapeutic efficacy of anti-PD-L1. Thus, dual targeting of CXCR2+ tumor cells and tumor-associated neutrophils remodels tumor microenvironment and enhances immunotherapy response in ARID1A-deficient PDAC, providing a new strategy for precision therapy of PDAC.

The evolution of the human brain underlies our higher-order cognitive functions. In particular, the cerebral cortex, the outermost layer of the brain, has rapidly evolved to contain a disproportionately large number of neurons relative to the rest of the brain. Much of this expansion is attributed to the enlargement and diversification of the pool of neural precursors, which proliferate and differentiate into the neurons and glia of the brain. How the human cerebral cortex has evolved remains an active area of investigation. With the advent of pluripotent stem cell and brain organoid technologies, comparative genomic studies between humans, mice, and nonhuman primates have identified human-specific genes or pathways during neurodevelopment. The utility of these models relies on the ability of brain organoids to preserve the cytoarchitecture and species-specific developmental trajectories of diverse neural and glial cell types that are observed in&#xa0;vivo. This review will discuss how brain organoids recapitulate aspects of interspecies differences during cortical development, specifically neural precursor expansion, neurogenesis, and gliogenesis, and how these models can be improved to enable a deeper understanding of human brain evolution. Unraveling the cellular and molecular mechanisms underlying cross-species differences in brain expansion could also provide key insights into neurodevelopmental diseases, particularly those where brain size is affected.

Prodrug nanoassemblies formed by the self-assembly of prodrugs represent an emerging platform, offering advantages such as high drug loading, facile preparation, and tumor selectivity. However, existing prodrug nanoassemblies primarily depend on noncovalent intermolecular interactions to maintain structural integrity, rendering them vulnerable to in vivo instability and severely constraining their clinical translation. To overcome those limitations, we introduce a mild and efficient thiol-ene click reaction to construct prodrug nanoassemblies reinforced by a covalently crosslinked network. Specifically, prodrugs are designed by conjugating cabazitaxel (CTX) to tri-alkene-containing side chains via tumor redox-responsive bonds. These prodrugs spontaneously assemble into nanoassemblies enriched with surface-exposed olefin groups, which are subsequently "locked" by covalent crosslinking using tetra-arm thiol crosslinkers. The resulting covalently crosslinked prodrug nanoassemblies exhibit markedly improved stability, leading to prolonged systemic circulation and enhanced tumor accumulation, thereby translating into superior antitumor efficacy. Moreover, the redox-cleavable bond enables tumor microenvironment-responsive drug release, effectively mitigating the systemic toxicity of CTX while preserving its antitumor potency. Collectively, this covalent "locking" strategy provides a notable advancement in optimizing the structural stability of prodrug nanoassemblies and offers a promising strategy for developing novel chemotherapeutic delivery platforms that integrate circulatory stability with tumor selectivity.

In some purple phototrophic bacteria, the enzyme spheroidene monooxygenase (CrtA) catalyses the final step of carotenoid biosynthesis, introducing a keto group at the C2 position of spheroidene to produce spheroidenone. CrtA from the model purple bacterium Cereibacter (previously Rhodobacter) sphaeroides has a C-terminal extension consisting of a disordered, proline-rich sequence followed by a short region containing a significant proportion of glycine residues; the role of this extension is not understood. In addition to the accumulation of spheroidene, a C. sphaeroides &#x394;crtA mutant generated in a previous study had a slower growth rate and made fewer photosynthetic complexes than the wild type strain. We show here that these phenotypes are largely due to a polar effect of the crtA deletion on the downstream bchID bacteriochlorophyll biosynthesis genes. We generated a crtA mutant where bchID expression was not interrupted and used this background to test a series of CrtA C-terminal truncations to identify the minimal enzyme that retains spheroidene monooxygenase activity. Using structural modelling we identify the histidine residue that acts as the axial ligand to a heme group required for spheroidene monooxygenase activity, and two threonine residues found proximal to the bound carotenoid. We show that the subtle growth phenotype of this new &#x394;crtA mutant is due to the loss of the C-terminus of the enzyme rather than the altered carotenoid content of this strain. We further demonstrate that the C-terminal extension appears to mediate the association of CrtA with other membrane proteins, forming a range of high molecular mass complexes.

The purpose of this in vitro study was to evaluate the fracture load, both before and after aging, of implant-supported cantilevered prostheses with different prosthesis heights fabricated additively using an experimental resin and a commercially available resin, or subtractively from a high-impact polymer composite. Three cylindrical master files (20&#xa0;mm long and 11&#xa0;mm wide) were designed in three heights (7&#xa0;mm, 11&#xa0;mm, and 15&#xa0;mm), each containing a space for a titanium-base (Ti-base) abutment. Using these files, a total of 108 specimens were fabricated from an additively manufactured resin for definitive fixed partial dentures (TR), an additively manufactured experimental resin (SA), and a subtractively manufactured high-impact polymer composite (BR) (N = 12 per material-height pair). After fabrication, the specimens and corresponding Ti-base abutments were treated according to their manufacturers' instructions and cemented with an autopolymerizing luting composite. Each group was divided into nonaged and aged subgroups (n = 6 per material-height pair). Nonaged specimens were tested to fracture, while aged specimens first underwent cyclic loading (1.2 million cycles, 50 N, 1.7&#xa0;Hz) followed by the same load-to-fracture test on surviving specimens. Fracture load data were analyzed with generalized linear model analysis and Bonferroni-corrected post hoc tests (&#x3b1; = 0.05). All aged specimens survived cyclic loading and were subjected to the load-to-fracture test. The interaction among material, prosthesis height, and aging condition affected the fracture loads (p < 0.001). Among the 11-mm nonaged specimens, BR led to the highest fracture load, whereas among the 15-mm nonaged specimens, TR resulted in the lowest values (p &#x2264; 0.001). For nonaged BR, 7-mm height led to the lowest values, whereas for nonaged SA, 15-mm height led to the highest values (p &#x2264; 0.007). In addition, 15-mm height led to higher values than 7-mm height for aged BR and SA (p &#x2264; 0.010). Aging reduced the fracture load of 11-mm BR (p = 0.002). Regardless of the aging condition, 7-mm (BR) or 11-mm (SA and TR) prosthesis heights may be considered as minimal requirements for tested materials to withstand the masticatory forces of the molar region in a cantilevered implant-supported situation. The effed of aging on measured fracture loads was minimal.