BACKGROUND:Hexavalent chromium ions (Cr(VI)), a notorious toxic heavy metal pollutant with proven carcinogenicity, endangers human health and the environment. Meanwhile, l-ascorbic acid (L-AA), a vital biological antioxidant, has abnormal levels closely tied to various diseases. Developing efficient synchronous detection methods for these two key analytes is of great value in clinical and environmental monitoring. Traditional fluorescent nanomaterials, particularly those emitting in the blue/green region, suffer from limited tissue penetration depth and autofluorescence interference, hindering their application in deep-tissue imaging and real-time monitoring. Therefore, the development of red-emitting nanomaterials with enhanced optical properties and multifunctionality is crucial for advancing biosensing and bioimaging technologies. RESULTS:Herein, we present a facile hydrothermal synthesis of manganese-doped carbon dots (Mn-CDs) that exhibit red fluorescence (λex/λem = 520 nm/675 nm) and exceptional sensitivity for the simultaneous detection of Cr(VI) ions and L-AA. Mn-CDs were synthesized using o-phenylenediamine (OPD) and 2,5-diaminobenzenesulfonic acid (DSA) as precursors, along with manganese chloride tetrahydrate as a metal dopant source, achieving a high fluorescence quantum yield of 11 %. The Mn-CDs function as a dual-responsive "off-on-off" fluorescent sensor, demonstrating low detection limits of 0.44 μM for Cr(VI) and 1.11 μM for L-AA. Utilizing smartphone-integrated RGB analysis, the detection limits were further improved to 0.021 μM for Cr(VI) and 0.06 μM for L-AA. The Mn-CDs exhibit excellent biocompatibility and low cytotoxicity, enabling successful application in HeLa cells imaging and real-time intracellular monitoring of Cr(VI) and L-AA. SIGNIFICANCE:This study introduces a novel Mn-CDs-based fluorescent-colorimetric dual-mode probe that overcomes the limitations of traditional blue/green-emitting CDs by offering enhanced tissue penetration, minimized background interference, and multifunctional integration for biosensing and bioimaging. The integration of Mn-CDs with a smartphone-based analytical platform enhances their portability and user-friendliness for on-site detection, providing a valuable tool for heavy metal pollution monitoring and clinical biomarker detection. This work not only broadens the application scope of metal-doped carbon dots in biosensing but also provides a new strategy for environmental monitoring and clinical diagnostics, demonstrating significant application prospects in advancing biomedical research and clinical practice.

BACKGROUND:Multifunctional carbon dots (CDs) have gained prominence in biosensing, cell imaging, and nanomedicine due to their tunable fluorescence, excellent biocompatibility, and surface functionalizability. However, blue/green-emitting CDs suffer from limited tissue penetration and autofluorescence interference. Iron ions (Fe3+) and pyrophosphate ions (PPi) are crucial biomarkers in various biological processes, with deviations in their concentrations linked to various diseases including cancer. Therefore, the development of highly sensitive and selective sensors for Fe3+ and PPi detection is vital. To address these challenges, we present red-emitting nickel-doped carbon dots (Ni-CDs) synthesized via a simple one-pot hydrothermal method, offering advantages for deep-tissue imaging and therapeutics. RESULTS:Herein, we report a one-pot hydrothermal synthesis of nickel-doped CDs (Ni-CDs) that exhibit both paramagnetic responsiveness and red fluorescence (λex/λem = 475 nm/630 nm). Using citric acid and p-phenylenediamine as raw materials, we successfully fabricated Ni-CDs with high fluorescence quantum yield of 24 % and uniform size distribution (5.13 ± 0.04 nm). The Ni-CDs serve as an "on-off-on" fluorescent sensor for simultaneous detection of Fe3+ and PPi with low detection limits of 0.051 μM and 0.31 μM, respectively. They demonstrate high sensitivity and selectivity in detecting Fe3+ in real water samples and PPi in human urine and blood samples. Furthermore, Ni-CDs exhibit good biocompatibility and enable real-time visualization of intracellular Fe3+ and PPi dynamics in cancer cells. Under 808 nm laser irradiation (1.5 W/cm2), Ni-CDs achieve high photothermal conversion efficiency of 59.1 % and generate cytotoxic reactive oxygen species, leading to synergistic photothermal/photodynamic cancer cell apoptosis of 98.8 %. SIGNIFICANCE:This "two-in-one" theranostic platform based on Ni-CDs overcomes traditional limitations of conventional blue/green-emitting CDs, offering deep-tissue compatibility and minimized background interference, and multifunctional integration. Our methodology provides a generalized design strategy for wavelength-engineered CD hybrids, enabling innovative applications in point-of-care diagnostics and precision oncology. The multifunctional properties of Ni-CDs highlight their potential to revolutionize biomedical research and clinical practice.

Herein, we have pioneered a hydrothermal synthesis approach to fabricate red-emitting manganese-doped carbon dots (Mn-CDs), which exhibit a pronounced fluorescence peak at 665 nm under 525 nm excitation. This significant red-shift in emission wavelength not only minimizes autofluorescence interference but also enhances tissue penetration, making Mn-CDs highly promising for biological applications. Capitalizing on these optical properties, our study delves into the interactions between Mn-CD and trypsin, employing sophisticated spectral analysis and molecular docking techniques. Our findings reveal that Mn-CDs non-covalently bind to the catalytic center and microenvironment of trypsin through hydrogen bonds and van der Waals forces, inducing conformational changes and forming a stable complex that impedes enzymatic activity. In vitro assays further substantiate the competitive inhibitory effect of Mn-CDs on the trypsin's catalytic activity, with enzyme kinetics demonstrating a reduced Michaelis-Menten constant without altering the maximum catalytic velocity. Notably, gel electrophoresis, human cervical carcinoma cells digestion micro-imaging, and clone formation experiments collectively demonstrate that this inhibitory effect effectively shields human serum albumin and Hela cells from trypsin-mediated degradation. These insights into nanomaterial-protease interactions pave the way for innovative enzyme-regulated tumor therapies, harnessing the inhibitory properties of Mn-CDs to modulate protease activity within cancerous microenvironments. This research not only deepens our fundamental understanding of nano-bio interfaces but also propels the practical designs of diagnostic/therapeutic nanoplatforms for biomedical applications.

An efficient and feasible of the novel highly selective DNA–PK inhibitor AZD7648 was introduced. The route includes the following characteristics: (1) Intermediate (E)-N-hydroxy-N'-(4-methyl-5-nitropyridin-2-yl)formimidamide (4) was prepared from commercially available 4-methyl-5-nitropyridine-2-amine by “one-pot” method, and 7-methyl-[1,2,4]triazolo[1,5-a]pyridin-6-amine (6) was prepared in two steps with an improved yield of 55.5

Given the increasing use of bevacizumab in combinatorial drug therapy for a multitude of different cancer types, there is a need for therapeutic drug monitoring to analyze the possible correlation between drug trough concentration, and therapeutic effect and adverse reactions. An ultra-performance liquid chromatography tandem-mass spectrometry method was then developed and validated to determine bevacizumab levels in human plasma samples. Chromatographic separation was achieved on a Shimadzu InertSustainBio C18 HP column, whereas subsequent mass spectrometric analysis was performed using a Shimadzu 8050CL triple quadrupole mass spectrometer equipped with an electro-spray ionization source in the positive ion mode. In total, three multiple reaction monitoring transitions of each of the surrogate peptides were chosen with 'FTFSLDTSK' applied as the quantification peptide whereas 'VLIYFTSSLHSGVPSR' and 'STAYLQMNSLR' were designated as the verification peptides using the Skyline software. This analytical method was then fully validated, with specificity, linearity, lower limit of quantitation, accuracy, precision, stability, matrix effect and recovery calculated. The linearity of this method was developed to be within the concentration range 5-400 mu g/ml for bevacizumab in human plasma. Subsequently, eight patients with non-small cell lung cancer (NSCLC) were recruited and injected with bevacizumab over three periods of treatment to analyze their steady-state trough concentration and differences. To conclude, the results of the present study suggest that bevacizumab can be monitored in a therapeutic setting in patients with NSCLC.

Background: The abuse of the Phencyclidine-type substances, especially ketamine is a serious problem worldwide, and retrospective analysis are important for both the analysis and the identification of forms of drug abuse. The current major analytical methods, while all excellent in terms of accuracy, are time- and reagent-consuming. This depletion is made even more unfortunate by the fact that a large number of samples are negative in retrospective analyses. It is clear that a set of methods that can be analyzed both accurately and quickly need to be developed and applied to the screening and analysis of large quantities of samples. Results: We described a urine test based on acoustic ejection mass spectrometry, which allows precise injection at very low volumes and near 1 ejection s(-1) and data acquisition. The confidence in identification was increased by the characterization of the abundance ratio of the two pairs of ions. Urine samples could be diluted with water and loaded into a 384-well plate for sampling without complicated sample preparation. The sample in the transparent 384-well plate was pre-scanned by the laser, and then 20 nL droplets were ejected into the ion source for targeted analysis of 2 ion transitions per droplet totaling 9 targeted analytes in the sequence of acquisition methods. It took 90 min to screen 250 samples in this approach, yielding 10 ng mL(-1) detection limits. Positive samples were further analyzed by UHPLC-MS/MS for confirmation and quantification of up to 36 analytes. Significance: This was the first fast screening method for phencyclidine-type substances based on acoustic ejection mass spectrometry, which greatly reduces the analytical time, and can accomplish in 1.5 h what UHPLC-MS/MS needs 3 days to complete. And the samples can be analyzed without complicated sample preparation, and also can obtain good detectability. It was applied to a short-term retrospective analysis in Shanghai, and its accuracy was also extremely high.

In this paper, Au-modified Co3O4 hollow nanospheres/graphene composites (Au-Co3O4/rGO) were synthesized for the first time through a novel "one-pot cooking" method at ambient temperature. The hollow nanospheres exhibited a particle size of approximately 10-15 nm, while the modified Au nanoparticles were about 4-5 nm in diameter. A high-efficiency and high response H2S gas sensor was constructed based on Au-Co3O4/rGO ternary composites. The effects of different Au modifying mass ratios on the H2S gas-sensitive performance of the composites were systematically investigated. At an operational temperature of 92 degrees C, the Au-Co3O4/rGO sensor, incorporating an Au loading mass ratio of 1.3 wt%, exhibited a response value of 175.4 for H2S at 100 ppm, a recovery time of 30 s, and a detection limit reaching as low as 10 ppb. This response was tripled compared to the undoped Co3O4/rGO sensor. At the same time, the H2S sensing mechanism by Au-Co3O4/rGO was discussed in detail.

Highly sensitive and selective detection of microRNA-21 (miRNA-21) in biological samples is critical for the disease diagnosis and cancer treatment. In this study, a nitrogen-doped carbon dots (N-CDs)-based ratio fluorescence sensing strategy was constructed for miRNA-21 detection with high sensitivity and excellent specificity. Bright-blue N-CDs (λex/λem = 378 nm/460 nm) were synthesized by facile one-step microwave-assisted pyrolysis method by using uric acid as the single precursor, and the absolute fluorescence quantum yield and fluorescence lifetime of N-CDs were 35.8% and 5.54 ns separately. The padlock probe hybridized with miRNA-21 firstly and then was cyclized by T4 RNA ligase 2 to form a circular template. At the present of dNTPs and phi29 DNA polymerase, the oligonucleotide sequence in miRNA-21 was prolonged to hybridize with the surplus oligonucleotide sequences in circular template, generating long and reduplicated oligonucleotide sequences containing abundant guanine nucleotides. Separate G-quadruplex sequences were generated after the addition of Nt.BbvCI nicking endonuclease, and then hemin bound with G-quadruplex sequence to construct the G-quadruplex DNAzyme. Such G-quadruplex DNAzyme catalyzed the redox reaction of o-phenylenediamine (OPD) with H2O2, finally producing the yellowish-brown 2,3-diaminophenazine (DAP) (λem = 562 nm). Due to the inner filter effect between N-CDs and DAP, the ratio fluorescence signal of DAP with N-CDs was utilized for sensitive detection of miRNA-21 with detection limit of 0.87 pM. Such approach has practical feasibility and excellent specificity for miRNA-21 analysis during highly homological miRNA family in HeLa cell lysates and human serum samples.

In forensic toxicology, hair has become a hot biological material for drug testing due to its wider detection window and noninvasive sampling process compared to traditional liquid biological materials (e.g., blood and urine). However, hair as a matrix differs from body fluids, as it is not as easily aliquoted for analysis. Nevertheless, pretreatment methods for hair detection have gradually improved from the first chemical methods, such as alkali digestion and acid hydrolysis, to now include the physical method of pulverization and further improvements beyond "pulverization" protocols. In a previous study, we updated and developed a "micropulverized extraction" method. In the present study, our aim was to gain a more complete understanding of the "micropulverized extraction" method by comparing pulverization temperature and hair particle size, as these two factors are known to influence the effectiveness of sample processing. The analytes we selected were those commonly encountered in traditional drug abuse cases: (±)-methamphetamine, (±)-amphetamine, morphine, 6-acetylmorphine, cocaine, benzoylecgonine, (--)-∆9-tetrahydrocannabinol, ketamine, (±)-norketamine and (±)-3,4-methylenedioxymethamphetamine. The analysis method was liquid chromatography-tandem mass spectrometry.

In recent years, the incidence of cancer is high around the world, and the resistance of bacteria is increasing. To cope with the potentially adverse side effects of cancer chemotherapy and surgery, researchers are turning to the construction of new drug scaffolds. The indoline structure exists in a huge number of natural products, but drugs with indoline have only been formally studied in recent years. With the deepening of research, drugs containing indoline have played important roles in more disease treatment aspects, such as anti-tumor, anti-bacterial, anti-inflammatory and have been used as analgesics, to treat cardiovascular diseases and so on. The synthesis and pharmacological activity of indoline derivatives is summarized in this review in order to support the addition of the indoline component to the toolbox of medicinal chemists. This review focuses on the advantages of indoline compounds in development and synthesis of and for the use as anticancer drugs, antibacterial drugs, to treat cardiovascular diseases and as anti-inflammatory and analgesic drugs. Indoline structures are commonly found in natural and synthetic compounds with medicinal value and are now beginning to be exploited as the basic backbone of various drugs. As research continues, dihydroindoles and their derivatives will play a greater role in the medical field.

In this study, fluorescent red-carbon quantum dots (R-CQDs) with an ultrahigh fluorescence quantum yield of 45% were rapidly and easily synthesized by thermal pyrolysis of 2,5-diaminotoluene sulfate and 4-hydroxyethylpiperazineethanesulfonic acid using a one-step microwave-assisted hydrothermal approach. R-CQDs possessed the excitation-independent fluorescence property with the optimal emission peak at 607 nm under the excitation wavelength of 585 nm. R-CQDs exhibited excellent fluorescence stability under extremely harsh conditions in a pH range of 2-11, high ionic strength (1.8 M of NaCl), and long UV light irradiation time (160 min). The fluorescence quantum yield of these R-CQDs was as high as 45%, implying their preferable application in chemosensors and biological analysis. Because Fe3+ ion bound with R-CQDs and statically quenched the fluorescence of R-CQDs, the fluorescence intensity of R-CQDs was recovered after the addition of ascorbic acid (AA) via its redox reaction with Fe3+ ion. R-CQDs were developed as highly sensitive fluorescent on-off-on probes for sequentially sensing Fe3+ ions and AA. Under the optimal experimental conditions, the linear range for Fe3+ ion detection was 1-70 μM with a detection limit of 0.28 μM, and the linear range for AA detection was 1-50 μM with a detection limit of 0.42 μM. The successful detection of Fe3+ ions in authentic water samples and the successful sensing of AA in human body fluids and vitamin C tablets further proved the practical application prospects of this efficient strategy in the environmental protection and disease diagnosis fields.

In this paper, the binding interaction thermodynamics of black phosphorus quantum dots (BPQDs) with bovine serum albumin (BSA) was explored systematically and comprehensively to interpret the influence of BPQDs on both the conformational structure and the biological function of BSA. The results of a variety of spectroscopic strategies and molecular simulation technique revealed that the endogenous fluorescence of BSA was quenched by BPQDs spontaneously via the static quenching mechanism based on the main binding forces of van der Waals interaction and hydrogen bonds formation. BPQDs interacted strongly with the Sudlow's site I of BSA via stoichiometric ratio of 1:1 to construct the novel stable ground-state complex. The results of three-dimensional fluorescence spectrometry and circular dichroism spectroscopy showed that BPQDs reduced the prominent alpha-helix structure content and the thermal stability of BSA through concentration-dependent manner. These results not only disclose the binding interaction mech- anism of BPQDs with BSA comprehensively but also illustrate the variation of the secondary structure of BSA after its association with BPQDs carefully. Such research paves the way for the targeted design of black phosphorus derivatives with excellent biocompatibility and the safety application of such nanopar- ticles in the clinic diagnosis and the effective therapy of serious diseases in human beings.(c) 2022 Elsevier B.V. All rights reserved.

Herein, efficient red carbon dots (R-CDs) were synthesized by one-step hydrothermal treatment of N-(4-amino phenyl) acetamide and (2,3-difluoro phenyl) boronic acid. The optimal emission peak of R-CDs was at 602 nm (under 520 nm excitation) and the absolute fluorescence quantum yield of R-CDs was 12.9%. Polydopamine, which was formed by the self-polymerization and cyclization of dopamine in alkaline condition, emitted char-acteristic fluorescence with peak position of 517 nm (under 420 nm excitation) and affected the fluorescence intensity of R-CDs through inner filter effect. L-Ascorbic acid (AA), which was the hydrolysis product of L-ascorbic acid-2-phosphate trisodium salt under the catalytic reaction of alkaline phosphatase (ALP), effectively prevented the polymerization of dopamine. Combined with the ALP-mediated AA production and the AA-mediated polydopamine generation, the ratiometric fluorescence signal of polydopamine with R-CDs was correlated closely with the concentration of both AA and ALP. Under optimal conditions, the detection limits of AA and ALP were 0.28 & mu;M during linear range of 0.5-30 & mu;M and 0.044 U/L with linear range of 0.05-8 U/L, respectively. This ratiometric fluorescence detection platform can efficiently shield the background interference of sophisticated samples by introducing a self-calibration as reference signal in a multi-excitation mode, which can detect AA and ALP in human serum samples with satisfactory results. Such R-CDs/polydopamine nano-composite provides a steadfast quantitative information and makes R-CDs be excellent candidate for biosensors via combining target recognition strategy.

In this paper, Ti3C2 quantum dots (Ti3C2 QDs) were synthesized by simply treating Ti3C2 MXene powder with acid and base via hydrothermal method. Ti3C2 QDs exhibited superior fluorescence property and were used for the fluorescent imaging of living HeLa cells successfully. In order to evaluate the influence of Ti3C2 QDs on protease with specific biological functions, binding interaction of Ti3C2 QDs with trypsin was studied comprehensively and deeply through spectroscopic strategies and molecular modeling technique. The intrinsic fluorescence of trypsin was spontaneously quenched by Ti3C2 QDs through static quenching mode under van der Waals interaction force, and Ti3C2 QDs bound with the inactive residue domain of trypsin firmly with stoichiometric ratio of 1:1. Ti3C2 QDs induced the microenvironmental variation of the amino acid residues in trypsin, reducing the thermal stability of trypsin significantly. Gel electrophoresis experiments and microscopic imaging experiments demonstrated that Ti3C2 QDs inhibited the enzymatic activity of trypsin on the digestion of human serum albumin and HeLa cells obviously. These results revealed not only the deep interaction mechanism between Ti3C2 QDs and protease but also the influence of Ti3C2 QDs on the enzymatic activity of trypsin, paving the way for the safe biological application of Ti3C2 QDs in the diagnosis and the therapy of protease-related diseases.

Objective: Smallpox, a severe infectious disease caused by the smallpox virus, causes a death rate as high as 30% within 15-20 days after infection. Therefore, development of anti-Smallpox product as a strategic reserve is urgently needed. Methods: We prepared and tested pepsin-digested F(ab′)2 fragments of serum IgG from horses. Results: Transmission electron microscopy indicated that the purified virus showed morphology consistent with VVTT. The titer was above 1.0 × 107 PFU/mL. The purity of the antigen exceeded 90%, according to HPLC. After purification and cleavage, the yield of the purified product F(ab′)2 was approximately 1.3%, its purity exceeded 90%, and the neutralizing antibody titer exceeded 1:3200. F(ab′)2 fragments had good preventive and therapeutic effects in mice at antibody doses of 5.2 mg/mL and 2.6 mg/mL. The viral loads of the drug-treated mice were suppressed to varying degrees, and the higher dose groups (5.2 and 2.6 mg/mL) showed a 2-3 fold lower viral load than that in the control group. Conclusion: A process for producing equine immunoglobulin F(ab′)2 against VVTT was established. The prepared horse anti-smallpox immunoglobulin product had good neutralizing antibody effects on VVTT. The highly purified preparation may serve as a potential candidate for smallpox treatment.

Phencyclidine (PCP) is a frequently abused dissociative agent. It causes confusion, increased tendencies toward violence, and concentration-dependent cytotoxicity after entry into the body. The parent nucleus of phencyclidine-type substances is arylcyclohexylamine, which is easy to modify; therefore, abusers and dealers can readily synthesize substitutes beyond the drug control catalog. An urgent need exists to establish screening methods for phencyclidine-type substances to provide technical support for abuse monitoring. In this study, 20 mg of hair was pulverized in 500 mL of methanol containing 0.5 ng/mL PCP-d5. After ultrasonication, centrifugation, and filtration, the supernatant was analyzed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) operating in the multiple reaction monitoring mode. Phencyclidine-type substances were separated in 13 min on a biphenyl column using a mobile phase gradient composed of A (water, formic acid 0.1%, acetonitrile 5%, 20 mmol/L ammonium acetate) and B (acetonitrile). The developed and validated method showed good selectivity, sensitivity (limit of detection: 0.25-2 pg/mg and lower limit of quantitation: 0.5-4 pg/mg), linearity (R2 > 0.994), accuracy, and precision (< 20%), and a dilution effect. The method also showed good recovery and acceptable matrix effects for most of the targeted compounds. This analytical approach was successfully applied for the identification and quantification of phencyclidine-type substances in hair from 87 authentic forensic cases. Nine analytes were detected: ketamine (10.3-26211.3 pg/ mg), 2-F-2-oxo-PCE (11.5-4034.9 pg/mg), 2-FDCK (14.0-43290.2 pg/mg), 2-BrDCK (10.6-21170.0 pg/mg), nor2-FDCK (10.1-16767.4 pg/mg), tiletamine (10.1-3250.8 pg/mg), O-PCE (43.3-166.1 pg/mg), DCK (10.2-90.4 pg/mg), and norDCK (24.9-103.0 pg/mg).

Objective: Ricin is a highly toxic ribosome-inactivating lectin derived from castor beans. To date, no antidote is available to treat ricin-poisoned patients, and the development of a safe and effective antidote is urgently needed. Methods: First, ricin was prepared and used to construct a mouse model and a rhesus monkey model of ricin intoxication. Second, pepsin-digested F(ab′) 2 fragments of serum IgG from horses injected with Freund’s-adjuvanted purified ricin were prepared. Third, the protective efficacy was evaluated in mouse and rhesus monkey models of lethal ricin intoxication. Results: The purity quotient of the prepared ricin and F(ab′) 2 fragments exceeded 90% and 85% in the mouse and monkey models, respectively. The LD 50 of ricin in mice and rhesus monkeys was 2.7 and 9 μg/kg, respectively. A quantity of 6.25 and 1.85 mg/kg F(ab′) 2 was sufficient to treat lethal ricin intoxication in the mice and rhesus monkeys, respectively. Finally, the effect of this therapeutic antibody on peripheral blood immune cells was examined by analysis of peripheral blood immune cells through single cell sequencing. The underlying mechanism was found to involve restraining neutrophil activation, proliferation, and differentiation. Conclusion: Purified F(ab′) 2 fragments administered with needle-free devices fully protect mice and rhesus monkeys against lethal doses of ricin intoxication.

In this paper, BiVO4 nanostructures with different morphologies were synthesized via hydrothermal method with the assistances of polyvinyl pyrrolidone (PVP), cetyltrimethyl ammonium bromide (CTAB), and sodium dodecyl benzene sulfonate (SDBS). The structures and the photocatalytic activities of BiVO4, PVP-assisted BiVO4 (BiVO4-PVP), CTAB-assisted BiVO4 (BiVO4-CTAB), and SDBS-assisted BiVO4 (BiVO4-SDBS) were characterized systematically by various techniques and organic pollution degradation experiment. The photocatalytic performance of these nanoparticles on the degradation of rhodamine B (RhB) was as follows: BiVO4-SDBS > BiVO4-CTAB > commercial photocatalyst P25 (under UV light irradiation) > BiVO4 > BiVO4-PVP > commercial photocatalyst P25 (under visible light irradiation). Irregular flake-stacked BiVO4-SDBS exhibited smaller crystallite size and larger specific surface area (3.9 m2/g) than irregular blocky BiVO4, rice-grained BiVO4-PVP, and polyhedral BiVO4-CTAB, leading to the shortened diffusion distance of electron-hole pairs and the enhanced separation efficiency of photogenerated electron-hole pairs. Due to the efficient electron-hole pairs separation and the enhanced visible light absorption, 2.0 g/L of BiVO4-SDBS showed the complete photocatalytic degradation rate of 100% on RhB (10 mg/L, 50 mL) in aqueous solution with pH 2 after irradiating under visible light for 40 min. The holes and superoxygen radical played vital roles in the photocatalytic degradation of RhB. Such investigation provides guidance for the rational design of visible light-active photocatalysts for the degradation of organic pollutants in wastewater.

(1) Background: With the resurgence of brucellosis epidemics in China in recent years, the chances of a brucella coinfection with other common respiratory pathogens, such as the influenza virus, have increased dramatically. However, little is known about the pathogenicity or the mechanisms of brucella and influenza coinfections. (2) Methods: To clarify the interventions in the early stages of lung damage due to brucella and influenza coinfections, we evaluated the effect of the coinfection on disease progression and mortality using a coinfection model in WT mice and NLRP6−/− mice, and we verified the function of NLRP6 in infection and proinflammation. (3) Results: The coinfection induced significant respiratory symptoms, weight loss, and a high mortality rate in WT mice. Influenza in the coinfection group significantly increased brucella proliferation in a synergistic manner. Meanwhile, a histological examination showed severe lung tissue destruction and excessive inflammatory responses in coinfected WT animals, and the expression of NLRP6 and IL-18 was dramatically increased in the lung tissues. Furthermore, NLRP6 deletion attenuated lung injuries and inflammation, a reduced bacterial load, and decreased IL-18 protein expression. (4) Conclusions: Our findings indicated that NLRP6 plays a critical role and might be a promising potential therapeutic target for brucella–influenza coinfections.

A fluorescence “on–off-on” strategy was established for the determination of nitrite in aqueous solution based on fluorine and nitrogen co-doped near-infrared carbon dots (NIR-CDs). NIR-CDs were prepared via one-step hydrothermal method by using N-(4-aminophenyl)-acetamide and 4,5-difluorobenzene-1,2-diamine as precursors. The photoluminescence quantum yield of NIR-CDs reaches to 17.4%, and the optimal emission peak of NIR-CDs is 675 nm under excitation of 530 nm. The Stokes shift of NIR-CDs (145 nm) is higher than that of some CDs with longer emission wavelengths. The red bathophenanthroline disulfonic acid (BPS)-Fe2+ complex can quench the fluorescence of NIR-CDs via inner filter effect and static quench modes. Nitrite can oxidize Fe2+ to produce Fe3+ in acidic environment, resulting in not only the formation of colorless and unstable BPS-Fe3+ complex but also the fluorescence recovery of NIR-CDs. This fluorescence “on–off-on” phenomenon also comes with the color variation of the mixture, resulting in both the fluorescence and the visual determination of nitrite. Under optimal conditions, this assay exhibits a good linear range from 1 to 50 μM and a low detection limit of 0.056 μM for nitrite determination. The method showed good applicability for nitrite determination in soil extract, human urine, and water samples with acceptable results. A convenient fluorescence “on–off-on” strategy for nitrite detection based on fluorine and nitrogen co-doped near-infrared carbon dots (NIR-CDs) and bathophenanthroline disulfonic acid (BPS)-Fe2+ complex was innovatively established. This probe showed a low detection limit of 0.056 μM for nitrite in authentic samples, which offered a new sight for fluorescent and visual detection of nitrite in environmental protection and human health areas.