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A sulfonated polyimide, S-F-abSPI, with alkyl sulfonic acid side chains, and a polyphosphonitrile derivative, poly[4-methoxyphenoxy (4-fluorophenoxy) phosphazene] (PFMPP), were designed and synthesized. Composite modification of the S-F-abSPI membrane was carried out using PFMPP, resulting in the preparation of composite membranes with different composite ratios, which were then subjected to performance testing and characterization. Experimental results revealed a significant enhancement in the proton conductivity of the S-F-abSPI membrane, reaching 0.116 S cm -1 , slightly higher than that of the N212 membrane. The S-F-abSPI/1% PFMPP composite membrane exhibited the optimal comprehensive performance, with a surface resistance as low as 0.54 Ω cm 2 , comparable to that of the N212 membrane. At a high current density of 200 mA cm -2 during charge-discharge, the composite membrane achieved a voltage efficiency (VE) of 83.12% and an energy efficiency (EE) of 81.95%. Cycling tests over 200 cycles demonstrated the composite membrane's excellent long-term cycling stability. The alkyl sulfonic acid side chains enhanced the proton conductivity of the membrane, while electrostatic potential distribution calculations indicated strong interactions between PFMPP and the base membrane, enhancing the membrane's mechanical strength, reducing vanadium ion permeability, and improving chemical stability and vanadium ion selectivity. This composite membrane holds promise for high-performance VRFB applications.

The stability of electrocatalysts during the hydrogen evolution reaction (HER) is vital for efficient production of hydrogen energy. Herein, we demonstrate that silver nanowire aerogel-based support (AABS) could facilitate the construction of HER catalysts with extraordinary long-term stability. A full nanostructure catalyst of nickel phosphide based formed on AABS (Ni 2 P-Ni 5 P 4 @AABS) was prepared to achieve an overpotential of 687 mV (without iR compensation) for HER at the current density of 1 A cm -2 in 0.5 M H 2 SO 4 . Excitingly, the stable HER performance was kept for 42 days during the long-term stability (i-t) test at high current density (0.5-1 A cm -2 ). The excellent HER performance of the Ni 2 P-Ni 5 P 4 @AABS catalyst is attributed to rapid electron transport pathways, numerous more accessible active sites, and support induced enhanced catalytic activity. The support effect was highlighted by a proposed phenomenological two-channel model for electron transport, which provides fresh insights into the design strategy for energy storage and delivery.

Indole alkaloids are privileged secondary metabolites, and their production may be achieved by the microbial biotransformation of tryptophan analogues. By feeding 1-methyl-L-tryptophan (1-MT) into the culture of endophytic Nigrospora chinensis GGY-3, six novel ( 1 - 6 ) and seven known indole alkaloids ( 7 - 13 ) were generated. Their structures were elucidated by means of NMR spectroscopy, experimental electronic circular dichroism (ECD) spectra, and X-ray crystallography analysis. A Friedel-Crafts reaction was proposed as the key reaction responsible for the formation of the new compounds. Racemates 4 and 6 were separated into isomers by chiral HPLC, with their absolute configurations determined by X-ray and ECD calculation. Compounds 3 , 4 , and 8 display good herbicidal activity against dicotyledon weed Eclipta prostrata , of which 4 and 8 exhibited 88.50% and 100% inhibition rates on the radicle at 200 μg/mL, respectively, a similar effect compared to the positive control penoxsulam.

Wildfires generate abundant smoke primarily composed of fine-mode aerosols. However, accurately measuring the fine-mode aerosol optical depth (fAOD) is highly uncertain in most existing satellite-based aerosol products. Deep learning offers promise for inferring fAOD, but little has been done using multiangle satellite data. We developed an innovative angle-dependent deep-learning model (ADLM) that accounts for angular diversity in dual-angle observations. The model captures aerosol properties observed from dual angles in the contiguous United States and explores the potential of Greenhouse gases Observing Satellite-2's (GOSAT-2) measurements to retrieve fAOD at a 460 m spatial resolution. The ADLM demonstrates a strong performance through rigorous validation against ground-based data, revealing small biases. By comparison, the official fAOD product from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Visible Infrared Imaging Radiometer Suite (VIIRS), and the Multiangle Imaging Spectroradiometer (MISR) during wildfire events is underestimated by more than 40% over western USA. This leads to significant differences in estimates of aerosol radiative forcing (ARF) from wildfires. The ADLM shows more than 20% stronger ARF than the MODIS, VIIRS, and MISR estimates, highlighting a greater impact of wildfire fAOD on Earth's energy balance.

Fine-mode aerosol optical depth (fAOD) is a vital proxy for the concentration of anthropogenic aerosols in the atmosphere. Currently, the limited data length and high uncertainty of the satellite-based data diminish the applicability of fAOD for climate research. Here, we propose a novel pretrained deep learning framework that can extract information underlying each satellite pixel and use it to create new latent features that can be employed for improving retrieval accuracy in regions without in situ data. With the proposed model, we developed a new global fAOD (at 0.5 μm) data from 2001 to 2020, resulting in a 10% improvement in the overall correlation coefficient ( R ) during site-based independent validation and a 15% enhancement in non-AERONET site areas validation. Over the past two decades, there has been a noticeable downward trend in global fAOD (-1.39 × 10 -3 /year). Compared to the general deep-learning model, our method reduces the global trend's previously overestimated magnitude by 7% per year. China has experienced the most significant decline (-5.07 × 10 -3 /year), which is 3 times greater than the global trend. Conversely, India has shown a significant increase (7.86 × 10 -4 /year). This study bridges the gap between sparse in situ observations and abundant satellite measurements, thereby improving predictive models for global patterns of fAOD and other climate factors.

Calcium ion batteries (CIBs) are a promising energy storage device due to the low redox potential of the Ca metal and the abundant reserves of the Ca element. However, the large radius and divalent nature of Ca 2+ lead to its slow ion diffusion kinetics and the lack of suitable electrode materials for Ca storage. Here, a layered structure of Na 2 Ti 3 O 7 (NTO) is presented as an anode material for nonaqueous CIBs. This NTO anode demonstrates a high discharge capacity of 165 mA h g -1 at 100 mA g -1 and a remarkable capacity retention rate of 80%, even after 2000 cycles at 500 mA g -1 , surpassing the performance of all reported intercalation-type anode materials for CIBs. The NTO transfers to layered Ca VII Na IX Ti 3 O 7 (CNTO) with intercalation of Ca 2+ and extraction of Na + during the first discharge process. Then, the CNTO undergoes the reversible insertion/extraction of Ca 2+ during subsequent cycling. Additionally, density functional theory calculations reveal that NTO possesses a rapid two-dimensional diffusion pathway for Ca 2+ . Moreover, the full CIBs based on NTO as the anode further underscore its potential for CIBs. This work presents promising anode materials for CIBs, offering opportunities to promote the development of high-performance CIBs.

Rivers have been recognized as the primary conveyors of microplastics to the oceans, and seaward transport flux of riverine microplastics is an issue of global attention. However, there is a significant discrepancy in how microplastic concentration is expressed in field occurrence investigations (number concentration) and in mass flux (mass concentration). Of urgent need is to establish efficient conversion models to correlate these two important paradigms. Here, we first established an abundant environmental microplastic dataset and then employed a deep neural residual network (ResNet50) to successfully separate microplastics into fiber, fragment, and pellet shapes with 92.67% accuracy. We also used the circularity ( C ) parameter to represent the surface shape alteration of pellet-shaped microplastics, which always have a more uneven surface than other shapes. Furthermore, we added thickness information to two-dimensional images, which has been ignored by most prior research because labor-intensive processes were required. Eventually, a set of accurate models for microplastic mass conversion was developed, with absolute estimation errors of 7.1, 3.1, 0.2, and 0.9% for pellet (0.50 ≤ C < 0.75), pellet (0.75 ≤ C ≤ 1.00), fiber, and fragment microplastics, respectively; environmental samples have validated that this set is significantly faster (saves ∼2 h/100 MPs) and less biased (7-fold lower estimation errors) compared to previous empirical models.

Hydrodynamic dimension (HD) is the primary indicator of the size of bioconjugated particles and biomolecules. It is an important parameter in the study of solid-liquid two-phase dynamics. HD dynamic monitoring is crucial for precise and customized medical research as it enables the investigation of the continuous changes in the physicochemical characteristics of biomolecules in response to external stimuli. However, current HD measurements based on Brownian motion, such as dynamic light scattering (DLS), are inadequate for meeting the polydisperse sample demands of dynamic monitoring. In this paper, we propose MMQCM method samples of various types and HD dynamic monitoring. An alternating magnetic field of frequency ω m excites biomolecule-magnetic bead particles (bioMBs) to generate magnetization motion, and the quartz crystal microbalance (QCM) senses this motion to provide HD dynamic monitoring. Specifically, the magnetization motion is modulated onto the thickness-shear oscillation of the QCM at the frequency ω q . By analysis of the frequency spectrum of the QCM output signal, the ratio of the magnitudes of the real and imaginary parts of the components at frequency ω q ± 2ω m is extracted to characterize the particle size. Using the MMQCM approach, we successfully evaluated the size of bioMBs with different biomolecule concentrations. The 30 min HD dynamic monitoring was implemented. An increase of ∼10 nm in size was observed upon biomolecular structural stretching. Subsequently, the size of bioMBs gradually reduced due to the continuous dissociation of biomolecules, with a total reduction of 20∼40 nm. This HD dynamic monitoring demonstrates that the release of biomolecules can be regulated by controlling the duration of magnetic stimulation, providing valuable insights and guidance for controlled drug release in personalized precision medicine.

Tethered nonplanar aromatics (TNAs) make up an important class of nonplanar aromatic compounds showing unique features. However, the knowledge on the synthesis, structures, and properties of TNAs remains insufficient. In this work, a new type of TNAs, the tethered aromatic lactams, is synthesized via Pd-catalyzed consecutive intramolecular direct arylations. These molecules possess a helical ladder-type conjugated system of up to 13 fused rings. The overall yields ranged from 3.4 to 4.3%. The largest of the tethered aromatic lactams, 6L-Bu-C 14 , demonstrates a guest-adaptive hosting capability of TNAs for the first time. When binding fullerene guests, the cavity of 6L-Bu-C shows stronger binding with C 14 than with C 6L-Bu-C 14 shows stronger binding with C 70 than with C 60 due to the better convex-concave π-π interaction. P and M enantiomers of all tethered aromatic lactams show distinct and persistent chiroptical properties and demonstrate the potential of chiral TNAs as circularly polarized luminescence (CPL) emitters.

In this study, an effective method for preparation of bioactive galloylated procyanidin B2-3'- O -gallate (B2-3'-G) was first developed by incomplete depolymerization of grape seed polymeric procyanidins (PPCs) using l-cysteine (Cys) in the presence of citric acid. The structure-activity relationship of B2-3'-G was further evaluated in vitro through establishing lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells. The results suggested that the better protective effects of B2-3'-G against inflammation were attributed to its polymerization degree and the introduction of the galloyl group, compared to its four corresponding structural units. In vivo experiments demonstrated that the B2-3'-G prototype was distributed in plasma, small intestine, liver, lung, and brain. Remarkably, B2-3'-G was able to penetrate the blood-brain barrier and appeared to play an important role in improving brain health. Furthermore, a total of 18 metabolites were identified in tissues. Potential metabolic pathways, including reduction, methylation, hydration, desaturation, glucuronide conjugation, and sulfation, were suggested.

Emerging aqueous ammonium-ion batteries (AIBs) are considered inexpensive, highly safe, ecofriendly, and sustainable energy storage systems. Although some high-performance electrode materials have been reported for AIBs, a comprehensive understanding of the origin of the high ammonium-ion storage performance is still lacking. Herein, the percolating network of anionic vacancies is determined to be the origin of the superior ammonium-ion storage properties of the Prussian blue analogues based on ab initio molecular dynamics simulation and electrochemical kinetic analyses. Fe[Fe(CN) 6 ] with a percolating anionic vacancy network delivers an outstanding rate of 64.7 mAh g -1 at 2000 mA g -1 in addition to a capacity retention of 94.5% after 10 000 cycles. The low-strain intercalation ammonium-ion storage mechanism of highly deficient Fe Prussian blue with Fe as the redox center is revealed by in situ X-ray diffraction and ex situ X-ray absorption fine structure analysis. The results provide insights into the mechanism of ammonium-ion storage in Prussian blue analogues and guidance in the development of aqueous AIBs.

A series of Ca 3 Al 2 Ge 3 O 12 : x Dy 3+ , y Eu 3+ phosphors were successfully prepared by the high-temperature solid-phase method. The phase and morphology of the phosphors were studied by means of Rietveld refinement and scanning electron microscopy. The results show that the phase is pure, and the crystal structure is the Ia 3̅ d space group. In the Ca 3 Al 2 Ge 3 O 12 : x Dy 3+ phosphors, using 380 nm excitation, phosphors showed blue ( 4 F 9/2 → 6 H 15/2 ) and yellow ( 4 F 9/2 → 6 H 13/2 ) emission peaks at 481 and 581 nm, respectively. In Ca 3 Al 2 Ge 3 O 12 : x Dy 3+ , y Eu 3+ phosphors, the energy transfer was inferred by the spectrum overlap of Dy 3+ and Eu 3+ , and the lifetime attenuation was analyzed from the perspective of dynamics; finally, the band gap structure of the phosphors was analyzed by combining diffuse reflection spectra with the first principle, and the energy transfer mechanism and luminescence mechanism were elaborated by combining theory and practice. The transition from blue white light to red light can be achieved by tuning the range of y in Ca 3 Al 2 Ge 3 O 12 : 0.015Dy 3+ , y Eu 3+ . Wherein, when y = 0.07, phosphors, the chromaticity coordinate of warm white CIE is (0.3932, 0.3203), the color temperature is 3093 K, and the warm white light is synthesized. The thermal stability of the synthesized warm white phosphors is 90.1% (423 K), the thermal sensing factors are S amax = 5.51 × 10 -4 K -1 (303 K) and S rmax = 0.0359% K -1 (303 K), and the actual quantum efficiency is IQE = 52.48%. These results prove that Ca 3 Al 2 Ge 3 O 12 : Dy 3+ , Eu 3+ have good application prospects as single-component warm w-LED devices.

Coarse-mode aerosol optical depths (cAODs) are critical for understanding the impact of coarse particle sizes, especially dust aerosols, on climate. Currently, the limited data length and high uncertainty of satellite products diminish the applicability of cAOD for climate research. Here, we propose a spatiotemporal coaction deep-learning model (SCAM) for the retrieval of global land cAOD (500 nm) from 2001-2021. In contrast to conventional deep-learning models, the SCAM considers the impacts of spatiotemporal feature interactions and can simultaneously describe linear and nonlinear relationships for retrievals. Based on these unique characteristics, the SCAM considerably improved global daily cAOD accuracies and coverages (R = 0.82, root-mean-square error [RMSE] = 0.04). Compared to official products from the multiangle imaging spectroradiometer (MISR), the moderate resolution imaging spectroradiometer (MODIS), and the polarization and directionality of Earth's reflectances (POLDER) instrument, as well as the physical-deep learning (Phy-DL) derived cAOD, the SCAM cAOD improved the monthly R from 0.44 to 0.88 and more accurately captured over the desert regions. Based on the SCAM cAOD, daily dust cases decreased over the Sahara, Thar Desert, Gobi Desert, and Middle East during 2001-2021 (>3 × 10 -3 /year). The SCAM-retrieved cAOD can contribute considerably to resolving the climate change uncertainty related to coarse-mode aerosols. Our proposed method is highly valuable for reducing uncertainties regarding coarse aerosols and climate interactions.

The power conversion efficiency (PCE) of perovskite solar cells has improved quickly in the past few years, but the PCE is still much lower than the theoretical limit. The relatively high energy loss ( E loss ) is one of the critical factors limiting the PCE. To resolve the above issues, a synergistic modification strategy was used herein to minimize E loss . RbCl and potassium polyacrylate (K-PAM) were used to modify the SnO 2 layer. Additionally, Pb(Ac) 2 was introduced into PbI 2 to further improve the film quality. The synergistic modification strategy reduced the defects in SnO 2 and perovskite and improved the energy-level alignment, enabling significantly reduced E loss and enhanced photovoltaic performance. The best PCE of 24.07% was achieved, which was much higher than that of the control device (20.86%). The E loss was only 0.349 eV for the target device. Good stability was achieved for the cells made using modified SnO 2 and perovskite layers.

Ferroptosis, an iron-dependent regulated cell death, has been emerging as an early mechanism in anticancer drug-induced acute kidney injury (AKI) that may benefit therapeutic intervention. However, the lack of molecular imaging methods for in vivo detection of ferroptosis restricts the early diagnosis of anticancer drug-induced AKI. Herein, we developed a PET/ 19 F MRI dual-modal imaging probe for the monitoring of ferroptosis in AKI by chemically conjugating the Fe(II)-sensitive artemisinin (Art) motif and macrocyclic ligand 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) to the CF 3 -modified polyhedral oligomeric silsesquioxane (POSS) clusters, denoted as the PAD probe. The PAD probe could be converted into PA*D in the presence of Fe(II) ions and subsequently be intercepted by biological macromolecules nearby, thereby enhancing the retention effect in ferroptotic cells and tissues. After labeling with 68 Ga isotopes, the 68 Ga-labeled PAD probe in cisplatin (CDDP)-induced AKI mice displayed a significantly higher renal uptake level than that in normal mice. Moreover, the PAD probe with a precise chemical structure, relatively high 19 F content, and single 19 F resonance frequency allowed for interference-free and high-performance 19 F MRI that could detect the onset of CDDP-induced AKI at least 24 h earlier than the typical clinical/preclinical assays. Our study provides a robust dual-modal molecular imaging tool for the early diagnosis and mechanistic investigation of various ferroptosis-related diseases.

Inflammation-related diseases affect large populations of people in the world and cause substantial healthcare burdens, which results in significant costs in time, material, and labor. Preventing or relieving uncontrolled inflammation is critical for the treatment of these diseases. Herein, we report a new strategy for alleviating inflammation by macrophage reprogramming via targeted reactive oxygen species (ROS) scavenging and cyclooxygenase-2 (COX-2) downregulation. As a proof of concept, we synthesize a multifunctional compound named MCI containing a mannose-based macrophage targeting moiety, an indomethacin (IMC)-based segment for inhibiting COX-2, and a caffeic acid (CAF)-based section for ROS clearance. As revealed by a series of in vitro experiments, MCI could significantly attenuate the expression of COX-2 and the level of ROS, leading to M1 to M2 macrophage reprogramming, as evidenced by the reduction and the elevation in the levels of pro-inflammatory M1 markers and anti-inflammatory M2 markers, respectively. Furthermore, in vivo experiments show MCI's promising therapeutic effects on rheumatoid arthritis (RA). Our work illustrates the success of targeted macrophage reprogramming for inflammation alleviation, which sheds light on the development of new anti-inflammatory drugs.

Multiphoton upconversion super-resolution microscopy (MPUM) is a promising imaging modality, which can provide increased resolution and penetration depth by using nonlinear near-infrared emission light through the so-called transparent biological window. However, a high excitation power is needed to achieve emission saturation, which increases phototoxicity. Here, we present an approach to realize the nonlinear saturation emission under a low excitation power by a simply designed on-chip mirror. The interference of the local electromagnetic field can easily confine the point spread function to a specific area to increase the excitation efficiency, which enables emission saturation under a lower excitation power. With no additional complexity, the mirror assists to decrease the excitation power by 10-fold and facilities the achievement of a lateral resolution around 35 nm, 1/28th of the excitation wavelength, in imaging of a single nanoparticle on-chip. This method offers a simple solution for super-resolution enhancement by a predesigned on-chip device.

Fluorine-19 magnetic resonance imaging ( 19 F MRI) is gaining widespread interest from the fields of biomolecule detection, cell tracking, and diagnosis, benefiting from its negligible background, deep tissue penetration, and multispectral capacity. However, a wide range of 19 F MRI probes are in great demand for the development of multispectral 19 F MRI due to the limited number of high-performance 19 F MRI probes. Herein, we report a type of water-soluble molecular 19 F MRI nanoprobe by conjugating fluorine-containing moieties with a polyhedral oligomeric silsesquioxane (POSS) cluster for multispectral color-coded 19 F MRI. These chemically precise fluorinated molecular clusters are of excellent aqueous solubility with relatively high 19 F contents and of single 19 F resonance frequency with suitable longitudinal and transverse relaxation times for high-performance 19 F MRI. We construct three POSS-based molecular nanoprobes with distinct 19 F chemical shifts at -71.91, -123.23, and -60.18 ppm and achieve interference-free multispectral color-coded 19 F MRI of labeled cells in vitro and in vivo . Moreover, in vivo 19 F MRI reveals that these molecular nanoprobes could selectively accumulate in tumors and undergo rapid renal clearance afterward, illustrating their favorable in vivo behavior for biomedical applications. This study provides an efficient strategy to expand the 19 F probe libraries for multispectral 19 F MRI in biomedical research.

A type II polyketide synthase biosynthetic gene cluster ( nap ) was identified in Streptomyces eurocidicus CGMCC 4.1086 via genome mining. The heterologous expression of the cryptic nap gene cluster in Streptomyces albus J1074 generated dimerized aromatic polyketide naphthocyclinones ( 1-3 ), whose structures were determined via extensive analysis using nuclear magnetic resonance and high-resolution electrospray ionization mass spectroscopy. The biological pathway of naphthocyclinone synthesis was revealed via in vivo gene deletion, in vitro biochemical reactions, and comparative genomics. Remarkably, 3 played a crucial role in inhibiting Phytophthora capsici and Phytophthora sojae , with EC 50 values of 6.1 and 20.2 μg/mL, respectively. Furthermore, 3 exhibited a potent protective effect against P. capsici and P. sojae in greenhouse tests.

Modification of the charge transport layers is an effective way to improve charge transport and performance of perovskite solar cells (PSCs). The ions in the ionic compounds used for the modification of SnO 2 may migrate into the perovskite layer, which harms the stability of PSCs. In this work, a low-cost, water-soluble nonionic polymer polyacrylamide (PAM) is used to modify SnO 2 . The addition of PAM improves the uniformity, wettability, and electron mobility of the SnO 2 film. Through the modification of SnO 2 , the defects of perovskite films are reduced and the grain size is increased. Furthermore, the energy-level alignment at the SnO 2 /perovskite interface is improved, which is beneficial to the transfer of electrons from perovskite to SnO 2 . Finally, the power conversion efficiency (PCE) of PSCs formed from modified SnO 2 is enhanced to 22.59%. More importantly, the unencapsulated devices with modified SnO 2 retain 90% of the initial value after storage for more than 1000 h under a relative humidity of 50%. These results indicate that modifying SnO 2 using PAM is a promising strategy to improve the performance of PSCs.

Halloysite-based tubular nanorockets with chemical-/light-controlled self-propulsion and on-demand acceleration in velocity are reported. The nanorockets are fabricated by modifying halloysite nanotubes with nanoparticles of silver (Ag) and light-responsive α-Fe 2 O 3 to prepare a composite of Ag-Fe 2 O 3 /HNTs. Compared to the traditional fabrication of tubular micro-/nanomotors, this strategy has merits in employing natural clay as substrates of an asymmetric tubular structure, of abundance, and of no complex instruments required. The velocity of self-propelled Ag-Fe 2 O 3 /HNTs nanorockets in fuel (3.0% H 2 O 2 ) was ca. 1.7 times higher under the irradiation of visible light than that in darkness. Such light-enhanced propulsion can be wirelessly modulated by adjusting light intensity and H 2 O 2 concentration. The highly repeatable and controlled "weak/strong" propulsion can be implemented by turning a light on and off. With the synergistic coupling of the photocatalysis of the Ag-Fe 2 O 3 heterostructure and advanced oxidation in H 2 O 2 /visible light conditions, the Ag-Fe 2 O 3 /HNTs nanorockets achieve an enhanced performance of wastewater remediation. A test was done by the catalytic degradation of tetracycline hydrochloride. The light-enhanced propulsion is demonstrated to accelerate the degradation kinetics dramatically. All of these results illustrated that such motors can achieve efficient water remediation and open a new path for the photodegradation of organic pollutions.

Small-area metal-halide perovskite solar cells (PSCs) having power-conversion efficiencies (PCEs) of greater than 25% can be prepared by using a spin-coated perovskite layer, but this technique is not readily transferrable to large-scale manufacturing. Drop-casting is a simple alternative method for film formation that is more closely aligned to industry-relevant coating processes. In the present work, drop-casting was used to prepare films for screening two-dimensional Ruddlesden-Popper (2DRP) metal-halide perovskite formulations for potential utility in PSCs, without additional processing steps such as inert-gas blowing or application of antisolvent. The composition of the 2DRP formulation used for drop-casting was found to have a profound effect on optical, spectroscopic, morphological, and phase-distribution properties of the films as well as the photovoltaic performance of related PSC devices. This facile method for screening film quality greatly assists in speeding up the identification of perovskite formulations of interest. The optimal 2DRP perovskite formulation identified from screening was utilized for industry-relevant one-step roll-to-roll slot-die coating on a flexible plastic substrate, producing PSCs having PCEs of up to 8.8%. A mechanism describing film formation and phase distribution in the films is also proposed.

Antibodies, particularly of the immunoglobulin G (IgG) isotype, are a group of biomolecules that are extensively used as affinity reagents for many applications in research, disease diagnostics, and therapy. Most of these applications require antibodies to be modified with specific functional moieties, including fluorophores, drugs, and proteins. Thus, a variety of methodologies have been developed for the covalent labeling of antibodies. The most common methods stably attach functional molecules to lysine or cysteine residues, which unavoidably results in heterogeneous products that cannot be further purified. In an effort to prepare homogeneous antibody conjugates, bioorthogonal handles have been site-specifically introduced via enzymatic treatment, genetic code expansion, or genetically encoded tagging, followed by functionalization using bioorthogonal conjugation reactions. The resulting homogeneous products have proven superior to their heterogeneous counterparts for both in vitro and in vivo usage. Nevertheless, additional chemical treatment or protein engineering of antibodies is required for incorporation of the bioorthogonal handles, processes that often affect antibody folding, stability, and/or production yield and cost. Accordingly, concurrent with advances in the fields of bioorthogonal chemistry and protein engineering, there is growing interest in site-specifically labeling native (nonengineered) antibodies without chemical or enzymatic treatments. In this review, we highlight recent strategies for producing site-specific native antibody conjugates and provide a comprehensive summary of the merits and disadvantages of these strategies.

Bovine milk-derived exosomes (BMDEs) have potential applications in the pharmaceutical industry as drug delivery carriers. A comprehensive analysis of protein glycosylation in exosomes is necessary to elucidate the process of targeted delivery. In this work, free oligosaccharides (FOSs), O -glycans, and N -glycans in BMDEs and whey were first analyzed through multiple derivation strategies. In summary, 13 FOSs, 44 O -glycans, and 94 N -glycans were identified in bovine milk. To analyze site-specific glycosylation of glycoproteins, a one-step method was used to enrich and characterize intact glycopeptides. A total of 1359 proteins including 114 glycoproteins were identified and most of these were located in the exosomes. Approximately 95 glycopeptides were initially discovered and 5 predicted glycosites were confirmed in BMDEs. Collectively, these findings revealed the characterization and distribution of glycans and glycoproteins in BMDEs, providing insight into the potential applications of BMDEs in drug delivery and food science.

The precise transplantation, long-term tracking, and maintenance of stem cells with maximizing therapeutic effect are significant challenges in stem cell-based therapy for stroke treatment. In this study, a unique core-shell labeling nanoagent was prepared by encapsulating a cobalt protoporphyrin IX (CoPP)-loaded mesoporous silica nanoparticle (CPMSN) into a 125 I-conjugated/spermine-modified dextran polymer ( 125 I-SD) by microfluidics for mesenchymal stem cell (MSC) tracking and activity maintenance. The CPMSN core not only exhibits excellent photoacoustic (PA) imaging performance induced by the intermolecular aggregation of CoPP within the mesopores but also protects the MSCs against oxidative stress by sustained release of CoPP. Meanwhile, the addition of a 125 I-SD shell can increase the uptake efficiency in MSCs without inducing cell variability and enable the single-photon-emission computed tomography (SPECT) nuclear imaging. In vivo results indicated that CPMSN@ 125 I-SD labeling could allow for an optimal combination of instant imaging of MSCs, with PA to guide intracerebral injection, followed by multiple time point SPECT imaging to consecutively track the cell homing. Importantly, the sustained release of CoPP from CPMSN@ 125 I-SD significantly increased the survival of MSCs after injection into an ischemic mouse brain and promoted neurobehavioral recovery in ischemic mice. Thus, CPMSN@ 125 I-SD represents a robust theranostic probe for both MSC tracking and maintaining their therapeutic effect in the treatment of brain ischemia.

Herein, CoFe 2 O 4 nanoparticles were directly synthesized through a solution combustion method using ferric nitrate, cobalt nitrate, and glycine as raw materials. The effects of glycine on the phase composition and magnetic properties of the CoFe 2 O 4 products were investigated. When the fuel/ferric nitrate ratio was 0.8, the obtained product was pure CoFe 2 O 4 with an average particle size of 25 nm. Furthermore, the saturation magnetization is 77.3 emu/g, which is about 95.7% that of CoFe 2 O 4 bulk materials at room temperature and good for recycling. The photo-Fenton catalytic properties of CoFe 2 O 4 were investigated for assessing its efficacy in removing dyes. It could degrade the 20 ppm MB in 75 min. To improve the photo-Fenton catalytic performance, NH 4 HCO 3 and glucose were employed as additives. Due to the pores formed by NH 4 HCO 3 and glucose, the G-CoFe 2 O 4 and N-CoFe 2 O 4 could degrade the 20 ppm MB in 40 and 25 min, respectively. The results indicated that these additives can effectively improve the catalytic activity of CoFe 2 O 4 . The modified CoFe 2 O 4 is a promising alternative recyclable photo-Fenton catalyst for removing organic dyes., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

Layered perovskite films, composed of two-dimensional (2D) Ruddlesden-Popper perovskites (RPPs), show improved stability compared to their conventional three-dimensional (3D) counterparts in perovskite solar cells (PSCs). However, 2D PSCs exhibit a lower power conversion efficiency (PCE), which has been attributed to compositional inhomogeneity and nonuniform alignment of the 2D perovskite phases. Methylammonium chloride (MACl) has been adopted as an additive to improve the PCE and the operational stability of 2D PSCs, although the role of MACl in performance enhancement is unclear. In this work, time- and spatially resolved fluorescence and absorption techniques have been applied to study the composition and charge carrier dynamics in MACl-doped BA 2 MA 4 Pb 5 I 16 (⟨ n ⟩ = 5) layered perovskite films. The inhomogeneous phase orientation distribution in the direction orthogonal to the substrate for undoped layered perovskite films undergoes reorganization upon MACl doping. Based on structural and crystallographic analyses, it is revealed that MACl can facilitate the crystallization of small- n 2D perovskite phases at the cost of consuming an increased amount of BA cations. Consequently, an increase in the thickness of large- n 2D perovskite phases accompanies their enhanced perpendicular alignment ([101] crystalline orientation) to the substrate, which facilitates charge carrier transport and collection by electrodes. The defect passivation of the MACl-doped layered perovskite film provided by the small- n phase is also beneficial to the photovoltaic performance of the PSC device. A maximum PCE (∼14.3%) was achieved at 6 mol % MACl doping, with this optimum level influenced by the increased interfacial roughness of the layered perovskite film caused by the edges of small- n perovskite flakes emerging on the front surface.

Efficient signal amplification is essential to construct ultrasensitive biosensors for biologically relevant species with abundant concomitant interferences. Here, we apply LbaCas12a as a signal amplifier to develop a versatile CRISPR-Cas12a platform to detect a wide range of analytes in ultralow concentrations. The platform relies on the indiscriminate single-stranded DNase activity of LbaCas12a, which recognizes single-stranded DNA intermediates generated by non-DNA targets down to femtomolar concentrations and subsequently enhances the fluorescence signal output. With the help of functional nucleotides (DNAzyme and aptamer), ultrasensitive bioassays for Pb 2+ and Acinetobacter baumannii have been designed with a limit of detection down to ∼0.053 nM and ∼3 CFU/mL, respectively. It also allows simultaneous detection of four microRNAs (miRNAs) at a picomolar concentration without significant interferences by other counterparts, suggesting the potential of multiplexed miRNA expression profiles analysis in high throughput. Given the versatility and generality of the CRISPR-Cas12a platform, we expect the current work to advance the application of CRISPR-Cas-based platforms in bioanalysis and provide new insights into ultrasensitive biosensor design.

The cyclophosphazene-based self-healing polymer electrolytes (CPSHPE) is designed and fabricated via the copolymerization of hexa(4-ethyl acrylate phenoxy) cyclotriphosphazene (HCP), (2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate) (UPyMA), and poly(ethylene glycol) methyl ether methacrylate (PEGMA) under UV irradiation. The cross-linking structure formed by HCP could effectively enhance the mechanical strength of the polymer electrolyte, and the cyclotriphosphazene as the core is able to improve the flame-retardant properties. Benefiting from the phenyl groups in HCP and the cross-linking structure, the CPSHPE shows high thermal stability (up to 300 °C). On the other hand, the supramolecular network fabricated by the dynamic ureido-pyrimidinone (UPy) dimers endows the polymer electrolyte with good self-healing capability and is expected to improve the reliability of polymer lithium batteries. Moreover, the cells were fabricated with LiFePO 4 (LFP), CPSHPE, and Li anodes show good reversible specific capacity. The CPSHPE could be a promising candidate as the multifunctional polymer electrolyte to improve the safety performance of lithium metal batteries.

Nanostructured materials with hollow interior voids are gaining great attention due to their fantastic geometries and unique physicochemical properties competent for many applications. However, the development of a fast approach to prepare the hollow structured particles remains challenging. Herein, a new and efficient in situ hard-template method was developed to synthesize hollow carbon nano- and microparticles using the as-prepared SiO 2 particles as a hard template directly, without any separation, drying, or redispersion. In this way, the hollow carbon particles with tunable diameters and shell thickness can be synthesized readily, which is simpler and more efficient than the traditional ones. In addition, the universality of this strategy allows us to study the different behaviors of hollow carbon particles in lithium-sulfur batteries when the architectures of hollow particles (i.e., diameter, shell thickness, etc.) were changed. We believe that this in situ method is applicable for synthesizing other core-shell or hollow structured materials (e.g., metal oxide), and also, the high performance of hollow carbon particles in lithium-sulfur batteries and beyond can be further explored., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

The metabolic activation and transformation of naphthalene by the cytochrome P450 enzyme (CYP 1B1) plays an important role in its potential carcinogenicity. The process has been explored by a quantum mechanics/molecular mechanics (QM/MM) computational method. Molecular dynamic simulations were performed to explore the interaction between naphthalene and CYP 1B1. Naphthalene involves α- and β-carbon, the electrophilic addition of which would result in different reaction pathways. Our computational results show that both additions on α- and β-carbon can generate naphthalene 1,2-oxide. The activation barrier for the addition on β-carbon is higher than that for the α-carbon by 2.6 kcal·mol -1 , which is possibly caused by the proximity between β-carbon and the iron-oxo group of Cpd I in the system. We also found that naphthalene 1,2-oxide is unstable and the O-C bond cleavage easily occurs via cellular hydronium ion, hydroxyl radical/anion; then it will convert to the potential ultimate carcinogen 1,2-naphthoquinone. The results demonstrate and inform a detailed process of generating naphthalene 1,2-oxide and new predictions for its conversion.

Histone ubiquitination affects the structure and function of nucleosomes through tightly regulated dynamic reversible processes. The efficient preparation of ubiquitinated histones and their analogs is important for biochemical and biophysical studies on histone ubiquitination. Here, we report the CAACU (cysteine-aminoethylation assisted chemical ubiquitination) strategy for the efficient synthesis of ubiquitinated histone analogs. The key step in the CAACU strategy is the installation of an N-alkylated 2-bromoethylamine derivative into a recombinant histone through cysteine aminoethylation, followed by native chemical ligation assisted by Seitz's auxiliary to produce mono- and diubiquitin (Ub) and small ubiquitin-like modifier (SUMO) modified histone analogs. This approach enables the rapid production of modified histones from recombinant proteins at about 1.5-6 mg/L expression. The thioether-containing isopeptide bonds in the products are chemically stable and bear only one atomic substitution in the structure, compared to their native counterparts. The ubiquitinated histone analogs prepared by CAACU can be readily reconstituted into nucleosomes and selectively recognized by relevant interacting proteins. The thioether-containing isopeptide bonds can also be recognized and hydrolyzed by deubiquitinases (DUBs). Cryo-electron microscopy (cryo-EM) of the nucleosome containing H2BK C 34Ub indicated that the obtained CAACU histones were of good quality for structural studies. Collectively, this work exemplifies the utility of the CAACU strategy for the simple and efficient production of homogeneous ubiquitinated and SUMOylated histones for biochemical and biophysical studies.

Phenyl-C 61 -butyric acid methyl ester (PCBM) is universally used as the electron-transport layer (ETL) in the low-cost inverted planar structure of perovskite solar cells (PeSCs). PCBM brings tremendous challenges in upscaling of PeSCs using industry-relevant methods due to its aggregation behavior, which undermines the power conversion efficiency and stability. Herein, we highlight these, seldom reported, challenges with PCBM. Furthermore, we investigate the potential of nonfullerene indacenodithiophene (IDT)-based molecules by employing a commercially available variant, 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3- d:2',3'- d']- s-indaceno[1,2- b:5,6- b'] dithiophene (ITIC), as a PCBM replacement in ambient-processed PeSCs. Films fabrication by laboratory-based spin-coating and industry-relevant slot-die coating methods are compared. Although similar power-conversion efficiencies are achieved with both types of ETL in a simple device structure fabricated by spin-coating, the nanofibriller morphology of ITIC compared to the aggregated morphology of PCBM films enables improved mechanical integrity and stability of ITIC devices. Upon slot-die coating, the aggregation of PCBM is exacerbated, leading to significantly lower power-conversion efficiency of devices than spin-coated PCBM as well as slot-die-coated ITIC devices. Our results clearly indicate that IDT-based molecules have great potential as an ETL in PeSCs, offering superior properties and upscaling compatibility than PCBM. Thus, we present a short summary of recently emerged nonfullerene IDT-based molecules from the field of organic solar cells and discuss their scope in PeSCs as electron or hole-transport layer.

Two-photon (TP) absorption nanomaterials are highly desirable for deep-tissue clinical diagnostics and orthotopic disease treatment. Here, a well-designed core/shell nanostructure was successfully synthesized with a ZnTPyP self-assembly nanocrystal (ZSN) inner core coated by a homogeneous TiO 2 layer outside (ZSN-TO). The ZSN is a good photosemiconductor, showing both one-photon (OP) and TP absorption properties for red fluorescence emission and electron-hole pair generation; TiO 2 with good biocompatibility acts as the electron acceptor, which can transfer photoelectron from ZSN to TiO 2 for highly effective electron-hole separation, favoring the production of long-life superoxide anion (O 2 •- ) by electrons and oxygen and strong oxidizing hydroxyl radical (•OH) by holes and surrounding H 2 O. Once pretreated with ZSN-TO, the simultaneous OP-405 nm or TP-800 nm laser stimulation and fluorescent imaging of reactive oxygen species (ROS) showed dynamical and continuous generation of ROS in HeLa cells, with cytotoxicity significantly increasing via the type-1-like photodynamic therapy process. The results demonstrated that the combination of organic ZSN with inorganic TiO 2 has great applications as an excellent photosensitizer for deep-tissue fluorescent imaging and noninvasive disease treatment via TP photodynamic therapy.

We report an all-atom molecular dynamics study of the structures and dynamics of salty water droplets on a silicon surface under the influence of applied electric field. Our simulation results support ion-specific effects on the elongation dynamics of salty nanodroplets, induced by the field. This feature has not been explored up to now in monovalent salts. Nevertheless, the importance of ion-specific effects is widely confirmed in biological and colloidal systems. In particular, the increase of salt concentration enhances the effect of the nature of ions on the wetting properties of droplets. In the presence of electric field (0.05 V Å -1 ), a complete spreading is implemented in a short time for different droplets at a concentration of 1 M, and the droplet morphology is stable, observed at long time scales. However, a higher salt concentration of 4 M considerably suppresses the spreading process owing to the increase of surface tension. It was found that the NaCl droplet shows deformation oscillations along the external field, but cannot fully wet the substrate surface. By contrast, the CsCl droplet reaches complete elongation rapidly and adopts a steady strip shape. The KCl droplet undergoes frequent transitions between breakup and connection. Additionally, the droplets can be elongated only when the electric field strength exceeds a threshold value. The dipole orientation of interfacial water and the ionic diffusion exhibit ion-specific dependences, but the hydrogen bond network is scarcely disturbed, excluding a concentration-dependent effect.

Self-assembly of amphiphilic block copolymers into well-defined nanostructures as drug delivery systems for the treatment of cancer has been a hot subject of research. However, sequential polymerizations synthesized amphiphilic block copolymers with covalent links suffered mainly from multistep synthesis and purification procedures as well as repeated optimization of polymer composition to form aggregates with well-defined structures. To overcome these drawbacks, supramolecular amphiphilic block copolymers with noncovalent links were developed to provide simplicity as required. Herein, we designed and prepared a reducible β-cyclodextran (β-CD)-ferrocene (Fc) double-head unit from which a dual-redox responsive supramolecular amphiphilic copolymer was fabricated together with a traditional polymer block through supramolecular induced polymerization. Typically, well-defined supramolecular micelles and vesicles were fabricated, respectively. Due to the integration of oxidation-sensitive noncovalent β-CD/Fc connections and reduction-sensitive covalent disulfide bridges in the polymer backbone, the resulting supramolecular micelles and vesicles showed structural deformation and accelerated drug release in response to both intracellular reducing and oxidizing environments, thus, presenting a new platform for both reactive oxygen species (ROS) and glutathione (GSH)-triggered anticancer drug delivery.

Photothermal conversion is one of the most important keys in the fields of solar collection, photo-hyperthermia, etc., and its performance is highly dependent on the photothermal conversion materials used. Especially in cancer photo-hyperthermia, the presently available small-molecule- or nanomaterial-based agents still suffer from numerous drawbacks, such as nonspecific accumulation and inevitable side effects on normal tissues. Here we identify a Mo-based polyoxometalate cluster that can change its dimension from small (1 nm) to big (tens of nanometer), favoring its intratumoral accumulation, and enhance photothermal conversion in response to the intratumoral acidity and reducibility, demonstrating a previously unrealized tumor-specific photo-hyperthermia. Distinct from the well-researched nano-based agents, a unique electronic structure of this cluster has been identified as the origin of the observed acidity-induced self-assembly and reduction-promoted NIR absorbance. In addition to providing a promising clinical agent, this finding is expected to establish a new physicochemical paradigm for photothermal materials design based on clusters.

Chemical protein synthesis can provide access to proteins with post-translational modifications or site-specific labelings. Although this technology is finding increasing applications in the studies of water-soluble globular proteins, chemical synthesis of membrane proteins remains elusive. In this report, a general and robust removable backbone modification (RBM) method is developed for the chemical synthesis of membrane proteins. This method uses an activated O-to-N acyl transfer auxiliary to install in the Fmoc solid-phase peptide synthesis process a RBM group with switchable reactivity toward trifluoroacetic acid. The method can be applied to versatile membrane proteins because the RBM group can be placed at any primary amino acid. With RBM, the membrane proteins and their segments behave almost as if they were water-soluble peptides and can be easily handled in the process of ligation, purification, and mass characterizations. After the full-length protein is assembled, the RBM group can be readily removed by trifluoroacetic acid. The efficiency and usefulness of the new method has been demonstrated by the successful synthesis of a two-transmembrane-domain protein (HCV p7 ion channel) with site-specific isotopic labeling and a four-transmembrane-domain protein (multidrug resistance transporter EmrE). This method enables practical synthesis of small- to medium-sized membrane proteins or membrane protein domains for biochemical and biophysical studies.

A new synthetic method for peptide thioesters is described using Fmoc solid-phase peptide synthesis (Fmoc-SPPS). This method employs a novel enamide motif to facilitate irreversible intramolecular N-to-S acyl migration, which can efficiently afford the desired peptide thioesters (3 h, 30 °C) under the final trifluoroacetic acid (TFA) cleavage conditions. The acyl-transfer-mediated approach for synthesis of peptide thioesters tolerated different C-terminal residues and was used to synthesize human C-C motif chemokine 11 (hCCL11) via native chemical ligation.

A simple method has been developed to produce SERS-active metal surfaces. Six metal surfaces (cadmium, nickel, gold, iron, copper, and silver) have been prepared on an aluminum foil underlayment by chemical reduction and strong surface-enhanced Raman signals have been observed for pyridine species on these surfaces. This permits the direct comparison of pyridine spectra on different metal surfaces prepared by the same chemically clean method. The differences among the SER spectra of the aqueous pyridine species using different metals generally follow the trend of silver, cadmium, nickel, iron, gold, and copper, which can be explained by the selective formation of alpha-pyridyl species and the equilibria between end-on adsorbed pyridines and edge-on adsorbed alpha-pyridyl species on the different metal surfaces.

(20S)-22-thiacholesterol (1) is found to be a potent competitive inhibitor of pregnenolone biosynthesis from cholesterol by purified reconstituted bovine adrenal cytochrome P-450scc. The apparent dissociation constant Kd, determined from difference spectra, is 0.6 microM, close to the value from kinetic studies for the apparent inhibition constant, Ki, of 0.8 microM. Studies of the time course of pregnenolone production indicate that under turnover conditions the competitive inhibitor (1) is converted to a tighter binding inhibitor, shown to be (20S,22R)-22-thiacholesterol S-oxide (4), with high diastereoselectivity and in a time-dependent manner. Both the diastereomeric sulfoxides, (20S,22S)-22-thiacholesterol S-oxide (3) and (20S,22R)-22-thiacholesterol S-oxide (4), exhibit properties consistent with their being competitive versus cholesterol, but the (22R)-sulfoxide (4) binds approximately 10 times more tightly than the (22S) diastereomer (3). The apparent Kd values of sulfoxides 4 and 3 are 0.1 and 1.14 microM, respectively. EPR and absorption spectroscopic studies of enzyme-inhibitor complexes suggest direct coordination of the oxygen atom of the (22R)-sulfoxide (4) with the catalytic heme center. This implies that the inhibitor operates by directly blocking further reaction at the active site heme group, with a substantial lifetime of the enzyme-inhibitor complex.