Enhanced visible light photocatalytic performance of carbon and oxygen co-doped carbon nitride with a three-dimensional structure: Performance and mechanism study

As a cost-effective photocatalyst, carbon nitride (g-C3N4) holds tremendous promise for addressing energy shortages and environmental pollution. However, its application is limited by disadvantages such as low specific surface area and easy recombination of photogenerated electron-hole pairs. This study introduces C and O co-doped g-C3N4 with a three-dimensional (3D) structure achieved through a straightforward one-step calcination process, demonstrating excellent photocatalytic activity of hydrogen production and oxytetracycline degradation, with superoxide radicals as the primary active species. We propose a plausible enhanced mechanism based on systematic characterizations and density functional theory calculations. The 3D structure confers a substantial specific surface area, enhancing both the adsorption area and active sites of catalysts while bolstering structural stability. Co-doping optimizes the band structure and electric conductivity of the catalyst, facilitating rapid migration of photogenerated charges. The synergistic effects of these enhancements significantly elevate the photocatalytic performance. This study presents a convenient and feasible method for the preparation of dual-regulated photocatalysts with outstanding performance.

Controlled synthesis of α-Fe2O3 nanocubes for gas-sensing applications: Feasibility of assessing crucian carp (Carassius auratus) freshness via trimethylamine levels

Trimethylamine (TMA) is an organic amine with strong pungent smell which is an indicator gas for evaluating fish freshness according to the international standard. In this work, as-synthesize α-Fe2O3 solid nanocubes (NCs), α-Fe2O3 nucleoshell NCs and α-Fe2O3 hollow NCs were used as sensing material to develop an outstanding TMA gas sensor. The response of the α-Fe2O3 hollow NCs sensors towards 20 ppm TMA at 230 ℃ was 6.3. Meanwhile, these sensors showed exceptional response/recovery time, low limit of detection, great selectivity, and outstanding linear relationship. Furthermore, the analysis of gases released during the decomposition of Carassius auratus (0-10 days) was conducted, which demonstrated the assessment of TMA by α-Fe2O3 hollow NCs sensor can evaluate the freshness of Carassius auratus. Such a novel sensor signifies the outstanding application potential in efficient gas-sensing properties of TMA, which will make the tremendous contribution for Carassius auratus product evaluation in the future.

Bimetallic Au and Pd Nanoparticles Modified WO3 Nanosheets for Enhancing the Sensitivity and Selectivity of Formaldehyde Assessment in Aquatic Products

Formaldehyde, a common illegal additive in aquatic products, poses a threat to people's health and lives. In this study, a novel metal oxide semiconductor gas sensor based on AuPd-modified WO3 nanosheets (NSs) had been developed for the highly efficient detection of formaldehyde. WO3 NS modified with 2.0% AuPd nanoparticles showed a higher response (Ra/Rg = 94.2) to 50 ppm of formaldehyde at 210 °C, which was 36 times more than the pristine WO3 NS. In addition, the AuPd/WO3 gas sensor had a relatively short response/recovery time of 10 s/9 s for 50 ppm of formaldehyde at 210 °C, with good immunity to other interfering gases and good stability for formaldehyde. The excellent gas-sensitive performance was attributed to the chemical sensitization of Au, the electronic sensitization of Pd, and the synergistic effect of bimetallic AuPd, which facilitated the recognition and response of formaldehyde molecules. Additionally, the high sensitivity and broad application prospect of the 2.0% AuPd/WO3 NS composite-based sensor in real sample detection were also confirmed by using the above sensor for the detection of formaldehyde in aquatic products such as squid and shrimp.

H2O2-triggered controllable carbon monoxide delivery for photothermally augmented gas therapy

Carbon monoxide (CO) gas therapy has shown great potential as a very promising approach in the ongoing fight against tumors. However, delivering unstable CO to the tumor site and safely releasing it for maximum efficacy still have unsatisfactory outcomes. In this study, we've developed nanotheranostics (IN-DPPCO NPs) based on conjugated polymer IN-DPP and carbon monoxide (CO) carrier polymer mPEG(CO) for photothermal augmented gas therapy. The IN-DPPCO NPs can release CO with the hydrogen peroxide (H2O2) overexpressed in the tumor microenvironment. Meanwhile, IN-DPPCO NPs exhibit strong absorption in the near-infrared window, showing a high photothermal conversion efficiency of up to 41.5% under 808 nm laser irradiation. In vitro and in vivo experiments demonstrate that these nanotheranostics exhibit good biocompatibility. Furthermore, the synergistic CO/photothermal therapy shows enhanced therapeutic efficacy compared to gas therapy alone. This work highlights the great promise of conjugated polymer nanoparticles as versatile nanocarriers for spatiotemporally controlled and on-demand delivery of gaseous messengers to achieve precision cancer theranostics.

Visible light-driven C/O-g-C3N4 activating peroxydisulfate to effectively inactivate antibiotic resistant bacteria and inhibit the transformation of antibiotic resistance genes: Insights on the mechanism

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) dissemination within water pose a serious threat to public health. Herein, C and O dual-doped g-C3N4 (C/O-g-C3N4) photocatalyst, fabricated via calcination treatment, was utilized to activate peroxydisulfate (PDS) to investigate the disinfection effect on tetracycline-resistant Escherichia coli and the transformation frequency of ARGs. As a result, approximately 7.08 log E. coli were inactivated, and 72.36 % and 53.96 % of antibiotics resistance gene (tetB) and 16 S rRNA were degraded respectively within 80 min. Futhermore, the transformation frequency was reduced to 0.8. Characterization and theoretical results indicated that C and O doping in g-C3N4 might lead to the electronic structure modulation and band gap energy reduction, resulting in the production of more free radicals. The mechanism analysis revealed that C/O-g-C3N4 exhibited a lower adsorption energy and reaction energy barrier for PDS compared to g-C3N4. This was beneficial for the homolysis of O-O bonds, forming SO4•- radicals. The attack of the generated active species led to oxidative stress in cells, resulting in damage to the electron transport chain and inhibition of ATP production. Our findings disclose a valuable insight for inactivating ARB, and provide a prospective strategy for ARGs dissemination in water contamination.

Design of flavonol-loaded cationic gold nanoparticles with enhanced antioxidant and antibacterial activities and their interaction with proteins

In this work, four structurally similar flavonols (galangin, kaempferol, quercetin and myricetin) were coated on the surface of (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide (MUTAB)‑gold nanoparticles (AuNPs) by two-step phase transfer and self-assembly, and the cationic MUTAB- AuNPs coated with flavonols (flavonol-MUTAB-AuNPs) were designed. Free radical scavenging and antibacterial experiments show that flavonol-MUTAB-AuNPs greatly improve the scavenging effect on DPPH, hydroxyl and superoxide anion radicals, and significantly enhance the inhibition effect on Staphylococcus aureus and Escherichia coli compared with flavonols and AuNPs. Then γ-globulin, fibrinogen, trypsin and pepsin were selected as representative proteins and their interaction with flavonol-MUTAB-AuNPs were investigated by various spectroscopic techniques. The fluorescence quenching mechanism of these four proteins by flavonol-MUTAB-AuNPs is static quenching. The binding constants Ka between them are in the range of 103 to 106. The interaction between them is endothermic, entropy-driven spontaneous process, and the main non-covalent force is the hydrophobic interaction. The effect of flavonol-MUTAB-AuNPs on the structure of the four proteins were investigated using UV-vis absorption spectra, synchronous fluorescence spectra and circular dichroism spectra. These results offer important insights into the essence of the interaction between flavonol-MUTAB-AuNPs and γ-globulin/fibrinogen/trypsin/pepsin. They will contribute to the development of safe and effective flavonol-MUTAB-AuNPs in biomedical fields.

Facile fabrication of 3D hollow porous aminopyridine rings decorated polymeric carbon nitride for enhanced photocatalytic hydrogen evolution and dye elimination

In consideration of energy shortages and environmental pollution, there is a critical need to develop a photocatalyst with high catalytic performance for rapid hydrogen production and efficient pollutant degradation. We synthesized a photocatalytic composite catalyst with three-dimensional (3D) porous aminopyridine rings grafted on the edge of g-C3N4 (APCN) using melamine, cyanuric acid and 4-aminopyridine as raw materials. The composite catalyst exhibited excellent photocatalytic performance for H2 production (2.44 mmol g-1h-1) and RhB degradation (97.08%) under visible light. Subsequently, a possible enhanced mechanism of the catalyst was proposed on the basis of a series of characterization and photocatalytic experiments. The 3D porous structure not only enhanced the structural stability but also increased the surface area of the APCN catalysts, which generated more exposed active sites. Moreover, the aminopyridine ring embellishment was beneficial for achieving a narrowed bandgap and charge migration and separation, which decreased the occurrence of photogenerated carrier recombination. In summary, these two structural features showed a synergistic effect to enhance the photocatalytic performance of the APCN catalyst. Finally, an integrated feasible enhanced mechanism of photocatalytic activity was elucidated according to the results of active substance capture tests, showing that O2•- played an important role during RhB degradation.

NIR-II Absorbing Conjugated Polymer Nanotheranostics for Thermal Initiated NO Enhanced Photothermal Therapy

Photothermal therapy (PTT) has received constant attention as a promising cancer treatment. However, PTT-induced inflammation can limit its effectiveness. To address this shortcoming, we developed second near-infrared (NIR-II) light-activated nanotheranostics (CPNPBs), which include a thermosensitive nitric oxide (NO) donor (BNN6) to enhance PTT. Under a 1064 nm laser irradiation, the conjugated polymer in CPNPBs serves as a photothermal agent for photothermal conversion, and the generated heat triggers the decomposition of BNN6 to release NO. The combination of hyperthermia and NO generation under single NIR-II laser irradiation allows enhanced thermal ablation of tumors. Consequently, CPNPBs can be exploited as potential candidates for NO-enhanced PTT, holding great promise for their clinical translational development.

A bioinspired polydopamine-FeS nanocomposite with high antimicrobial efficiency via NIR-mediated Fenton reaction

Ferrous and sulfur ions are essential elements for the human body, which play an active role in maintaining the body's normal physiology. Meanwhile, mussel-inspired polydopamine (PDA) possesses good hydrophilicity and biocompatibility. In the present work, ferrous sulfide embedded into polydopamine nanoparticles (PDA@FeS NPs) was designed and synthesized via a simple predoping polymerization-coprecipitation strategy and the intelligent PDA matrix successfully prevented the oxidation and agglomeration of FeS nanoparticles. Importantly, there was an obvious synergistic enhancement of the photothermal effect between polydopamine and ferrous sulfide. The PDA@FeS NPs exhibited excellent photothermal antibacterial effects against both E. coli and S. aureus. The near-infrared (NIR) light-mediated release of ferrous ions could reach about 26.5% under weakly acidic conditions, further triggering the Fenton reaction to produce toxic hydroxyl radicals (·OH) in the presence of hydrogen peroxide. The antibacterial mechanism could be attributed to cell membrane damage and cellular content leakage with the synergistic effect of PTT and CDT. This study highlighted the germicidal efficacy of PDA@FeS NPs and provided a new strategy for designing and developing next-generation antibacterial platforms.

Antipsychotics-induced improvement of cool executive function in individuals living with schizophrenia

Cool executive dysfunction is a crucial feature in people living with schizophrenia which is related to cognition impairment and the severity of the clinical symptoms. Based on electroencephalogram (EEG), our current study explored the change of brain network under the cool executive tasks in individuals living with schizophrenia before and after atypical antipsychotic treatment (before_TR vs. after_TR). 21 patients with schizophrenia and 24 healthy controls completed the cool executive tasks, involving the Tower of Hanoi Task (THT) and Trail-Marking Test A-B (TMT A-B). The results of this study uncovered that the reaction time of the after_TR group was much shorter than that of the before_TR group in the TMT-A and TMT-B. And the after_TR group showed fewer error numbers in the TMT-B than those of the before_TR group. Concerning the functional network, stronger DMN-like linkages were found in the before_TR group compared to the control group. Finally, we adopted a multiple linear regression model based on the change network properties to predict the patient's PANSS change ratio. Together, the findings deepened our understanding of cool executive function in individuals living with schizophrenia and might provide physiological information to reliably predict the clinical efficacy of schizophrenia after atypical antipsychotic treatment.

Enhanced adsorption and catalytic degradation of antibiotics by porous 0D/3D Co3O4/g-C3N4 activated peroxymonosulfate: An experimental and mechanistic study

In this work, Co₃O₄/g-C₃N₄ catalyst with highly efficient adsorption and degradation of antibiotics was developed based on the combination of three-dimensional (3D) porous morphological controls of g-C₃N₄ and the loading of Co₃O₄ quantum dots (Co₃O₄ QDs). It was discovered that the catalyst can effectively activate peroxymonosulfate (PMS) through a non-photochemical path, and a high tetracycline elimination rate of 99.7% can be achieved within 18 min. The characterization and density functional theory calculation results demonstrated that the porous 3D structure can not only promote the substrate adsorption reaction but also provide large surface area and countless exposed active sites for catalytic reaction. The introduction of Co₃O₄ QDs lowered activation energy barrier and lead to high energy of PMS adsorption. More efficient charge migration between the catalyst and PMS further accelerated PMS activation. Thus, leading to the excellent catalytic performance. In addition, non-free radical mediated degradation mechanism of catalytic activity was also proposed. This work provides a scheme for designing novel and efficient PMS activators for the removal of abusive antibiotics from aqueous environments.

The interaction mechanism between gold nanoparticles and proteins: Lysozyme, trypsin, pepsin, γ-globulin, and hemoglobin

In this study, the interaction between gold nanoparticles (AuNPs) and proteins (including lysozyme, trypsin, pepsin, γ-globulin and hemoglobin) was investigated by UV-visible absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy and protein activity assay. AuNPs was synthesized using reduction of HAuCl₄ with sodium citrate. The formation of AuNPs was confirmed from the characteristic surface plasmon resonance band at 521 nm and transmission electron microscopy revealed the average particle size was about 10 nm. The results reveal that AuNPs can interact with proteins to form a "protein corona (PC)", but the protein concentration required to form a relatively stable PC is not the same. The quenching mechanism of proteins by AuNPs is arisen from static quenching. The binding constants of AuNPs with proteins are in the range from 10⁶ to 10¹⁰ L mol^-1, and the order is pepsin > γ-globulin > hemoglobin > trypsin > lysozyme at 298 K. Van der Waals forces and hydrogen bonds are the main forces for the lysozyme-AuNPs system. The interaction between trypsin/pepsin/γ-globulin/hemoglobin and AuNPs is mainly by hydrophobic interaction. The addition of AuNPs has an effect on the secondary structure of proteins as confirmed from CD spectra. The change in secondary structure of different proteins is different and seems to have little relation with the binding constant. The activity of lysozyme/trypsin/pepsin decreases with the addition of AuNPs.

Comparative study on the interaction between flavonoids with different core structures and hyaluronidase

Hyaluronidase (HAase) is an important enzyme involved in a promoting inflammation pathway. Flavonoids are a group of major polyphenols including flavonols (such as myricetin and rutin), dihydroflavones (such as naringin and hesperidin), and isoflavones (such as genistein and puerarin), which have been proved to possess anti-inflammatory effects. In this study, the binding of the six flavonoids to HAase was investigated by steady state and time-resolved fluorescence, circular dichroism (CD) spectroscopy and molecular docking methods. Fluorescence data reveal that the fluorescence quenching mechanism of HAase by flavonoids is all static quenching procedure regardless of their core structure. The binding affinity is strongest for rutin and ranks in the order rutin > hesperidin > myricetin > puerarin > genistein > naringin. The thermodynamic analysis implies that hydrophobic interaction, electrostatic force and hydrogen bonding are the main interaction forces. Synchronous fluorescence spectroscopy and CD spectroscopy indicate that flavonoids have the same core structure and have similar effects on the microenvironment around Trp and Tyr residues and the secondary structure of HAase. The results of molecular docking show that the binding of flavonoids with the catalytic amino acid residues of HAase may lead to the decrease of enzyme activity.

Red-emitting fluorescent turn-on probe with specific isothiocyanate recognition site for cysteine imaging in living systems

Cysteine (Cys) is an effective biomarker in life systems and is closely related to a variety of diseases, so developing a specific and efficient detection method for Cys is of great significance. To date, extensive work has been undertaken toward this goal. However, the differentiation of Cys from other biothiols still represents a challenge from an experimental point of view. Toward this end, a selective and sensitive red-emitting probe (TMN-NCS) with an isothiocyanate (ITC)-based structure was proposed in this paper. A large Stokes shift (210 nm) was observed upon addition of Cys to a solution of TMN-NCS. In addition, TMN-NCS showed low toxicity, a low detection limit (120 nM), and excellent cell permeability. The results suggested that TMN-NCS holds great promise for biological applications.

Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Fluorescence experiments indicate that both naringenin and naringin can quench the intrinsic fluorescence of trypsin/pepsin via static quenching mechanism. Naringin binds trypsin/pepsin in a more firmly way than naringenin. Thermodynamic analysis reveals that the interactions of naringenin/naringin and trypsin/pepsin are synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic, electrostatic interactions and hydrogen bonding. Synchronous fluorescence spectroscopy, circular dichroism spectroscopy and FT-IR show that naringenin/naringin may induce microenvironmental and conformational changes of trypsin and pepsin. Molecular docking reveals that naringenin binds in the close vicinity of the active site (Ser-195) of trypsin and Asp-32 (the catalytic activity of pepsin) appears in naringin-pepsin system. The direct interactions between naringenin or naringin and catalytic amino acid residues will inhibit the catalytic activity of trypsin and pepsin, respectively. The results of molecular dynamic simulation validate the reliability of the docking results.

MiR-199a modulates autophagy and inflammation in rats with cerebral infarction via regulating mTOR expression

OBJECTIVE

The aim of this study was to investigate the roles of micro ribonucleic acid (miR)-199a in rats with cerebral infarction by regulating mammalian target of rapamycin (mTOR).

MATERIALS AND METHODS

A total of 36 Sprague-Dawley rats were randomly assigned into three groups, including: sham group (n=12), model group (n=12) and miR-199a mimics group (n=12). In sham group internal and external carotid arteries were exposed. The ischemia-reperfusion model was successfully established using suture embolization in the other two groups. After modeling, rats in sham group and model group were intraperitoneally injected with normal saline. However, rats in miR-199a mimics group were injected with miR-199a mimics. Following intervention for 3 d, sampling was conducted. Neurological deficit was evaluated in rats based on the Zea-Longa scoring system. Hematoxylin-eosin (HE) staining was performed to observe neuronal morphology. The expression of mTOR was detected using immunohistochemistry, and the relative expression level of tau protein was determined via Western blotting (WB). Besides, the messenger RNA (mRNA) expressions of mTOR and tau were detected by quantitative Polymerase Chain Reaction (qPCR). Finally, inflammatory factor content was measured through enzyme-linked immunosorbent assay (ELISA).

RESULTS

Model group and miR-199a mimics group exhibited a substantially higher Zea-Longa score than sham group (p<0.05). Compared with model group, the Zea-Longa score rose prominently in miR-199a mimics group (p<0.05). According to the results of HE staining, the structure of neurons in sham group was clear and intact, while the structure of neurons in model group was disordered. Meanwhile, neuronal morphology in miR-199a mimics group was significantly worse than that in model group (p<0.05). Immunohistochemistry results demonstrated that the positive expression level of mTOR was considerably upregulated in both model group and miR-199a mimics group in comparison with sham group (p<0.05). Moreover, its positive expression level in miR-199a mimics group was markedly higher that in model group (p<0.05). Based on the results of WB, model and miR-199a mimics groups exhibited a remarkably higher relative expression level of tau protein than sham group (p<0.05). However, the relative expression level of tau protein in miR-199a mimics group was prominently higher than that in model group (p<0.05). QPCR results manifested that the relative mRNA expression levels of mTOR and tau in model group and miR-199a mimics group were dramatically higher than those in sham group (p<0.05). Compared with those in model group, the relative mRNA expression levels of mTOR and tau increased significantly in miR-199a mimics group (p<0.05). ELISA results revealed that model group and miR-199a mimics group had prominently higher content of inflammatory factors than sham group (p<0.05). In addition, content of inflammatory factors in miR-199a mimics group was considerably higher than that in model group (p<0.05).

CONCLUSIONS

MiR-199a modulates mTOR expression to exert important regulatory effects on the autophagy and inflammation in rats with cerebral infarction.

Characterizing the air pollution of the cities in the closure of corona virus disease 2019 in China

With the rapid development of industrialization and urbanization in China, energy and vehicle consumption have continued to increase in recent years and air pollution has become serious. In early 2020, Corona Virus Disease 2019 broke out in Wuhan, China. From January 29, 2020, several sources of the air pollution almost all stopped working, including gasoline burning vehicles, dust producing building sites, coal-fired factories, etc. Five indicators of the atmospheric environmental quality were observed from December 19, 2019 to April 30, 2020 in nine cities and 1-h average concentrations, 24-h average concentrations and Air Quality Index were assessed. The 1-h average concentrations of the nitrogen dioxide, the ozone and the sulfur dioxide showed obvious difference though the closure did not change the sequence of the five pollutants' concentrations in the air at diverse sampling moments. The changing of the 24-h average concentrations of the five pollutants indicated the amount of pollutants in the air were greatly affected by human activities. The nitrogen dioxide, the sulfur dioxide and the particulate matters decreased obviously in the closure. The air in the metropolis and the south-east cities were relatively clean and the pollutants' concentrations decreased slightly during the closure period. The northern and the heavy industrial cities showed significant drop on air pollution indicators and the air quality of the two city groups could be greatly improved if some effective measures could be taken of environmental management and regional development.

Facile construction of N-doped carbon nanotubes encapsulating Co nanoparticles as a highly efficient multifunctional catalyst for electrochemical reactions

A multifunctional electrocatalyst, N-doped carbon nanotubes encapsulating Co nanoparticles (Co@NCNTs), has been synthesized by a facile solid-phase precursor pyrolysis method. It displays high performance for the ORR, OER and HER in alkaline medium.

Tunable and sustainable photocatalytic activity of photochromic Y-WO3 under visible light irradiation

Although photochromic and photocatalytic performance are the most significant features of WO3, the effects of photochromism on photocatalytic activities have not been investigated further. Herein, a novel gear-shaped WO3, with high coloration efficiency, fast reversibility, and remarkable photocatalytic performance was successfully prepared via a facile hydrothermal method. The influence of photochromic effects on its photocatalytic properties was evaluated under visible light irradiation. The results showed that the yellow WO3 sample exhibited higher photocatalytic efficiencies toward tetracycline hydrochloride (TCH), oxytetracycline (OTC), rhodamine B (RhB), and ciprofloxacin (CIP) (94.3%, 87.9%, 76%, and 68.6%, respectively, in 60 min). Further research found that the redox conversion between W6+ and W5+ played a key role in separating e-/h+ pairs. Importantly, the rapid and reversible conversion between W6+ and W5+ could be realized through light radiation or H2O2 treatment. Therefore, the gear-shaped WO3 possessed tunable and sustainable photocatalytic properties and maintained a high level of activity after recycling ten times under visible light irradiation. This work provides new insights into practical WO3 applications for environmental remediation based on photochromic regulation.

Controlled Synthesis of Pt Doped SnO2 Mesoporous Hollow Nanospheres for Highly Selective and Rapidly Detection of 3-Hydroxy-2-Butanone Biomarker

Listeria monocytogenes (L. monocytogenes) has been recognized as one of the extremely hazardous and potentially life-threatening food-borne pathogens, its real-time monitoring is of great importance to human health. Herein, a simple and effective method based on platinum sensitized tin dioxide semiconductor gas sensors has been proposed for selective and rapid detection of L. monocytogenes. Pt doped SnO2 nanospheres with particular mesoporous hollow structure have been synthesized successfully through a robust and template-free approach and used for the detection of 3-hydroxy-2-butanone biomarker of L. monocytogenes. The steady crystal structure, unique micromorphology, good monodispersit, and large specific surface area of the obtained materials have been confirmed by X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and Photoluminescence spectra (PL). Pt doped SnO2 mesoporous hollow nanosphere sensors reach the maximum response of 3-hydroxy-2-butanone at 250°C. Remarkably, sensors based on SnO2 mesoporous hollow nanospheres with 0.16 wt% Pt dopant exhibit excellent sensitivity (Rair/Rgas = 48.69) and short response/recovery time (11/20 s, respectively) to 10 ppm 3-hydroxy-2-butanone at the optimum working temperature. Moreover, 0.16 wt% Pt doped SnO2 gas sensors also present particularly low limit of detection (LOD = 0.5 ppm), superb long-term stability and prominent selectivity to 3-hydroxy-2-butanone. Such a gas sensor with high sensing performance foresees its tremendous application prospects for accurate and efficient detection of foodborne pathogens for the food security and public health.

TNF-derived peptides inhibit tumour growth and metastasis through cytolytic effects on tumour lymphatics

Tumour necrosis factor (TNF) is a multi-functional cytokine with profound and diverse effects on physiology and pathology. Identifying the molecular determinants underlying the functions and pathogenic effects of TNF is key to understanding its mechanisms of action and identifying new therapeutic opportunities based on this important molecule. Previously, we showed that some evolutionarily conserved peptides derived from TNF could induce cell death (e.g. apoptosis and/or necrosis), a feature of immune defence mechanisms shared by many vertebrates. In this study, we demonstrated that necrosis-inducing peptide P16 kills human glioblastoma cancer cells and primary human hepatoma or renal cancer cells isolated from patients who had not responded to standard treatments. Importantly, we show that the necrosis-inducing peptide P1516 significantly improves survival by inhibiting tumour metastasis in a 4T1 breast cancer syngeneic graft mouse model. Because the lymphatic system is an important metastatic route in many cancers, we also tested the effect of TNF-derived peptides on monolayers of primary human lymphatic endothelial cells (hDLEC) and found that they increased junctional permeability by inducing cytoskeletal reorganization, gap junction formation and cell death. Transmission electron microscopy imaging evidence, structural analysis and in-vitro liposome leakage experiments strongly suggest that this killing is due to the cytolytic nature of these peptides. P1516 provides another example of a pro-cytotoxic TNF peptide that probably functions as a cryptic necrotic factor released by TNF degradation. Its ability to inhibit tumour metastasis and improve survival may form the basis of a novel approach to cancer therapy.

Green synthesis of balsam pear-shaped BiVO4/BiPO4 nanocomposite for degradation of organic dye and antibiotic metronidazole

A novel balsam pear-shaped BiVO₄/BiPO₄ composite photocatalyst for a highly efficient degradation of organic dye and antibiotic was fabricated.

[Effects of transforming growth factor β1 receptor inhibitor SD-208 on human hypertrophic scar]

OBJECTIVE

To investigate the effects of transforming growth factor β1 (TGF-β1) receptor inhibitor SD-208 on human hypertrophic scar and its mechanisms.

METHODS

Scar fibroblasts were isolated from deprecated human hypertrophic scar tissue and then sub-cultured. Cells of the fifth passage were used in the following experiments. (1) Cells were divided into blank control group (BC) and 0.5, 1.0, 3.0, and 5.0 μmol/L SD-208 groups according to the random number table (the same grouping method below), with 6 wells in each group. Cells in group BC were added with 1 μL phosphate buffer solution, while cells in the latter four groups were added with 0.5, 1.0, 3.0, and 5.0 μmol/L SD-208, respectively. After being cultured for 12 hours, the proliferation activity of cells was detected by cell counting kit 8 and microplate reader (denoted as absorbance value). Suitable amount of substance concentration of SD-208 according to the results of proliferation activity of cells was chosen for the following experiments. (2) Another batch of cells were divided into group BC and 1, 3 μmol/L SD-208 groups and treated as in (1), with 8 wells in each group. The number of migration cells was detected by transwell method. (3) Another batch of cells were grouped and treated as in (2), and the microfilament morphology of cells was observed by rhodamine-phalloidin staining. (4) Another batch of cells were grouped and treated as in (2), and the protein expression of TGF-β1 was assessed with Western blotting. (5) Forty-eight BALB/c nude mice were divided into normal saline group (NS) and 1 μmol/L SD-208 group, and one longitudinal incision with length of 1 cm was made on their back. Then human hypertrophic scar tissue was embedded into the incision. On post injury day 7, multipoint injection of NS in a volume of 0.05 mL was performed in wounds of rats in group NS, while rats in 1 μmol/L SD-208 group were given 0.05 mL 1 μmol/L SD-208, once a day. On the day 0 (the same day), 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 post first time of injection, the weight of 8 nude mice was weighed by electronic scale, and scar area was measured by vernier caliper and the ratio of rest scar area was calculated. (6) In week 1, 2, and 3 post first time of injection, the protein expression of TGF-β1 of human hypertrophic scar tissue was assessed with Western blotting. Data were processed with one-way analysis of variance and two independent-sample t test.

RESULTS

(1) The proliferation activity of cells in group BC, 0.5, 1.0, 3.0, and 5.0 μmol/L SD-208 groups was respectively 1.00±0.03, 0.90±0.08, 0.68±0.11, 0.54±0.04, and 0.42±0.09, and the proliferation activity of cells in 0.5, 1.0, 3.0, and 5.0 μmol/L SD-208 groups was significantly lower than that in group BC (with t values from 2.9 to 22.1, P<0.05 or P<0.01). (2) The number of migration cells in 1, 3 μmol/L SD-208 groups was significantly less than that in group BC (with t values respectively 6.5 and 6.4, P values below 0.01). (3) Compared with that in group BC, fluorescence intensity of microfilaments of cells in 1, 3 μmol/L SD-208 groups was attenuated, and the pseudopod extended less. (4) The protein expressions of TGF-β1 of cells in group BC and 1, 3 μmol/L SD-208 groups were respectively 1.00±0.08, 0.80±0.08, and 0.61±0.05, and the protein expressions of TGF-β1 of cells in 1, 3 μmol/L SD-208 groups were significantly lower than those in group BC (with t values respectively 4.0 and 9.2, P values below 0.01). (5) The weights of nude mice in group NS and 1 μmol/L SD-208 group were similar on each time day (with t values from 0.2 to 1.1, P values above 0.05). The ratios of rest scar area of nude mice in two groups were decreased along with the injection time, and the ratios of rest scar area of nude mice in 1 μmol/L SD-208 group were significantly less than those in group NS from the day 6 to 20 post first time of injection (with t values from 1.8 to 15.9, P<0.05 or P<0.01). In week 1, 2, and 3 post first time of injection, the protein expressions of TGF-β1 of human hypertrophic scar tissue in nude mice in two groups showed a tendency of decrease, and the protein expressions of TGF-β1 of human hypertrophic scar tissue in nude mice in 1 μmol/L SD-208 group were significantly lower than those in group NS (with t values from 6.2 to 19.1, P values below 0.01).

CONCLUSIONS

SD-208 has significant inhibition effect on human hypertrophic scars, and the mechanism is correlated to the inhibition of protein expression of endogenous TGF-β1.

Oxidative treatment of diclofenac via ferrate(VI) in aqueous media: effect of surfactant additives

The potential reaction of diclofenac (DCF) with ferrate(VI) and influences of coexisting surfactants have not been investigated in depth, and are the focus of this study. The results demonstrated that DCF reacted effectively and rapidly with Fe(VI) and approximately 75% of DCF (0.03 mM) was removed by excess Fe(VI) (0.45 mM) within 10 min. All of the reactions followed pseudo first-order kinetics with respect to DCF and Fe(VI), where the apparent second-order rate constant (k_app) was 5.07 M^-1 s^-1 at pH 9.0. Furthermore, the degradation efficiencies of DCF were clearly dependent on the concentrations of dissolved organic matter additives in the substrate solution. Primarily, inhibitory effects were observed with the samples that contained anionic (sodium dodecyl-benzene sulfonate, SDBS) or non-ionic (Tween-80) surfactants, which have been attributed to the side reactions between Fe(VI) and surfactants, which led to a reduction in the available oxidant for DCF destruction. Furthermore, the addition of a cationic surfactant (cetyltrimethyl ammonium bromide, CTAB) and humic acid (HA) conveyed significantly promotional effects on the DCF-Fe(VI) reaction. The rate enhancement effect for CTAB might be due to micellar surface catalysis, through the Coulomb attraction between the reactants and positively charged surfactants, while the catalytic action for HA resulted from the additional oxidation of Fe(V)/Fe(IV) in the presence of HA. The results provided the basic knowledge required to understand the environmental relevance of DCF oxidation via Fe(VI) in the presence of surfactant additives.

Hysteroscopy combined dilatation and curettage, serum CA125 and CA19-9 play an important role in preserving fertility or endocrine function for early-stage endometrial cancer patients

OBJECTIVE

The aim of the study was to evaluate the role of hysteroscopy combined dilatation and curettage (D&C), serum CA125 and CA19-9 in endometrial cancer (EC) patients who desire to preserve fertility or endocrine function.

MATERIALS AND METHODS

This retrospective study included a total of 622 patients with EC between January 2006 and December 2014. The consistency of preoperative and postoperative histopathological findings were compared in patients who underwent D&C with or without hysteroscopy. The incidence of positive peritoneal cytology was also compared to assess the safety of hysteroscopy. Receiver operating characteristic (ROC) curve was used to evaluate the role of preoperative serum CA125 and CA19-9 in predicting extrauterine metastasis.

RESULTS

In 151 patients who underwent hysteroscopy combined D&C, the consistency of pre- and postoperative pathology was higher than the remaining 447 patients who underwent classical D&C alone (83.44% vs. 74.94%,p < 0.05) and there was no significant difference in the incidence of positive peritoneal cytology between the two groups (2.64% vs. 2.73%, p > 0.05). ROC curve analysis results showed the CA125 serum level of 31.75 U/ml and CA19-9 serum level of 35.40 U/ml were the best cutoff to predict extrauterine metastasis in endometrial cancer, with 66.7% sensitivity, 83% specificity, and 61.9% sensitivity and 84.9% of specificity, respectively.

CONCLUSIONS

Hysteroscopy combined D&C should be recommended for early-stage EC patients who desire to preserve fertility or endocrine function, and the preoperative serum levels of CA125 and CA19-9 were powerful in predicting tumor stage in these patients.

Detection of circulating tumour cells may add value in endometrial cancer management

OBJECTIVE

To evaluate the role of circulating tumour cells (CTCs) in patients with endometrial cancer (EC).

STUDY DESIGN

This study included 40 patients with a pre-operative diagnosis of high-risk EC between April 2015 and May 2016. Patients were further divided into high-risk (grade 3, non-endometrioid, myometrial invasion ≥1/2 and stage III-IV) and high-intermediate-risk (grade 2-3, endometrioid, myometrial invasion <1/2 and stage I-II) groups according to postoperative pathological results. CTCs were detected using the CellSearch system, and CTC results were correlated with standard clinicopathological characteristics and serum tumour marker CA125/HE4 status using Chi-squared test, continuity correction or Fisher's exact test. The pharmacodynamic effect was detected after the first cycle of adjuvant therapy. Patients were followed up for 13 months to assess outcomes.

RESULTS

Fifteen percent of patients had one or more CTCs. The presence of CTCs was found to be significantly associated with cervical involvement (83.33% vs 11.76%, p=0.00). No significant difference in CTC-positive rates was detected between the high-risk and high-intermediate-risk groups, and no significant correlation was found between CTCs and serum CA125/HE4, either by positive rates or exact serum levels of the conventional tumour markers. No more CTCs were detected after the first cycle of standard chemotherapy in this study, and no distant metastases or recurrence were found in the CTC-positive patients during the follow-up period.

CONCLUSION

The presence of CTCs was correlated with cervical involvement. Early-stage EC patients with CTCs may benefit from additional adjuvant therapies. Assessment of CTCs may be useful in the management of high-risk EC patients.

The Synthesis of a Coumarin Carbohydrazide Dinuclear Copper Complex Based Fluorescence Probe and Its Detection of Thiols

Small-molecule thiols, such as cysteine (CYS) and glutathione (GSH), are essential for maintaining the cellular redox environment and play important roles in regulating various cellular physiological functions. A fluorescence probe (compound 1-Cu²⁺) for thiols based on coumarin carbohydrazide dinuclear copper complex was developed. Compound 1 was synthesized from the reaction of 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide with 4-tert-butyl-2,6- diformylphenol. Accordingly, the copper complex (compound 1-Cu²⁺) was prepared by mixing compound 1 with 2 equivalents copper ions. Compound 1 had strong fluorescence while compound 1-Cu²⁺ hardly possessed fluorescence owing to the quenching nature of paramagnetism Cu²⁺ to the fluorescence molecule excited state. However, the fluorescence intensity of compound 1-Cu²⁺ was increased dramatically after the addition of thiol-containing amino acids, but not the other non-sulfhydryl amino acids. UV-vis absorption and fluorescence spectra indicated that compound 1-Cu²⁺ had good selectivity and sensitivity for thiols such as glutathione in CH₃CN:H₂O (3:2, v/v) PBS solution. The fluorescence imaging experiments implied that compound 1-Cu²⁺ has potential application in thiol-containing amino acids detection in living cells.

Binding of glutathione and melatonin to pepsin occurs via different binding mechanisms

Glutathione is a hydrophilic antioxidant and melatonin is a hydrophobic antioxidant, thus, the binding mechanism of the two antioxidants interacting with protease may be different. In this study, binding of glutathione and melatonin to pepsin has been studied using isothermal titration calorimetry (ITC), equilibrium microdialysis, UV-Vis absorption spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling. Thermodynamic investigations reveal that the binding of glutathione/melatonin to pepsin is driven by favorable enthalpy and unfavorable entropy, and the major driving forces are hydrogen bond and van der Waals force. ITC, equilibrium microdialysis, and molecular modeling reveal that the binding of glutathione to pepsin is characterized by a high number of binding sites. For melatonin, one molecule of melatonin combines with one molecule of pepsin. These results confirm that glutathione/melatonin interact with pepsin through two different binding mechanisms. In addition, the UV-Vis absorption and CD experiments indicate that glutathione and melatonin may induce conformational and microenvironmental changes of pepsin. The conformational changes of pepsin may affect its biological function as protease.

Oxidation of diclofenac with chlorine dioxide in aquatic environments: influences of different nitrogenous species

The oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug and emerging water pollutant, with chlorine dioxide was investigated under simulated water disinfection conditions. The reaction kinetics as functions of the initial concentrations of DCF, different nitrogenous species, and different pE values were experimentally determined. The results demonstrated that DCF reacted rapidly with ClO2, where more than 75 % of DCF (≤3.00 μM) was removed by 18.94 μM ClO2 within 60 s. All of the reactions followed pseudo first-order kinetics with respect to DCF, and the rate constant, k obs, exhibited a significant decrease from 4.21 × 10(-2) to 8.09 × 10(-3) s(-1), as the initial DCF concentration was increased from 1.00 to 5.00 μM. Furthermore, the degradation kinetics of DCF was clearly dependent on nitrogen-containing ion concentrations in the reaction solution. Ammonium and nitrite ions inhibited the DCF degradation by ClO2, whereas nitrate ion clearly initiated its promotion. In contrast, the inhibitory effect of NO2 (-) was more robust than that of NH4 (+). When the values of pE were gradually increased, the transformation of NH4 (+) to NO2 (-), and subsequently to NO3 (-), would occur, the rate constants were initially decreased, and then increased. When NH4 (+) and NO2 (-) coexisted, the inhibitory effect on the DCF degradation was less than the sum of the partial inhibitory effect. However, when NO2 (-) and NO3 (-) coexisted, the actual inhibition rate was greater than the theoretical estimate. These results indicated that the interaction of NH4 (+) and NO2 (-) was antagonistic, while the coexistence of NO2 (-) and NO3 (-) was observed to have a synergistic effect in aqueous environments.

Friedel–Crafts reaction of indoles with vicinal tricarbonyl compounds generated in situ from 1,3-dicarbonyl compounds and TEMPO: highly selective synthesis of tertiary alcohols

A novel Friedel–Crafts reaction of indoles with vicinal tricarbonyl compounds generated in situ has been developed, forming indolyl tertiary alcohols. The process involves disproportionation of TEMPO, α-oxyamination, N–O bond cleavage and, finally, addition of the indole.

Identification of marker genes in diabetic wounds by DNA microarray study

This study aimed to identify marker genes in diabetic wounds using a dataset based on a DNA microarray of dermal lymphatic endothelial cells, and our results provide a basic understanding of diabetic wounds through further study of these differentially expressed genes (DEGs). From the Gene Expression Omnibus database, we downloaded a gene expression microarray (GSE38396) that includes 8 samples: 4 normal controls and 4 disease samples (type II diabetes). We then identified genes that were differentially expressed between normal and disease samples using packages in R language, constructed a protein-protein interaction (PPI) network and analyzed modules in the network. In addition, phylogenetic analysis was performed by MEGA to find the most conserved genes. Two hundred and thirteen genes were identified as being differentially expressed between normal and disease samples, and we constructed a PPI network that included 213 pairs of proteins. We then identified a module including 20 genes, the function of which was significantly enriched in wounding response. Lastly, the most conserved genes, CD44 and CCL5, were identified through phylogenetic analysis. In summary, we found differentially expressed marker genes, a wounding response-related module, and the most important genes CD44 and CCL5. Our findings suggest new approaches to therapies for diabetic wounds.

Two-dimensional imaging of soot volume fraction by the use of laser-induced incandescence

A recently developed laser-induced incandescence technique is used to make novel planar measurements of soot volume fraction within turbulent diffusion flames and droplet flames. The two-dimensional imaging technique is developed and assessed by systematic experiments in a coannular laminar diffusion flame, in which the soot characteristics have been well established. With a single point calibration procedure, agreement to within 10% was found between the values of soot volume fraction measured by this technique and those determined by conventional laser scattering-extinction methods in the flame. As a demonstration of the wide range of applicability of the technique, soot volume fraction images are also obtained from both turbulent ethene diffusion flames and from a freely falling droplet flame that burns the mixture of 75% benzene and 25% methanol. For the turbulent diffusion flames, approximately an 80% reduction in soot volume fraction was found when the Reynolds number of the fuel jet increased from 4000 to 8000. In the droplet flame case, the distribution of soot field was found to be similar to that observed in coannular laminar diffusion flames.

Laser Raman spectrometry study on experimental galactose-induced cataract

PURPOSE

To observe the dynamic changes of hydration in galactose induced cataract.

METHODS

Two groups of Wistar rats were used in the experiment. There were 12 rats in the experimental group, which were fed diet of 50% D-Galactose standard feed; while the control group had 8 rats fed standard feed. Their other living conditions were the same. At desired time periods, two Wistar rats fed galactose and one normal control were selected and killed 20 minutes before the instrument examination respectively, then, their lenses were removed from the orbs by a posterior approach. The cleaned fresh lens was placed in a quartz cuvette with Tris buffered balanced salt solution containing 5.5 mmol/L glucose. The quartz cuvette was placed on the stage of the Spectrometer. The laser beam was focused at the lens nuclear from the bottom of the cuvette and the scattered light was collected at 90 degrees to the incident beam.

RESULTS

Raman spectroscopy showed that (1) during the formation of galactose cataract, the water signal (at 3390cm-1) increased obviously, and the ratio of I3390/I2935 increased from 0.31 (3 days) to 2.26 (17 days), which is correlated with the imbibition of water in the lens nuclear; (2) the hydration of lens nuclear could be divided into two phases. The ratio I3390/I2935 was increased slowly and steadily by 11 days after galactose feeding. Then, the ratio turned to increase quite fast till 17 days.

CONCLUSION

The hydration of nuclear is changed simultaneously with the formation of cataract. The hydration of nuclear is mainly due to the imbalance of Na+/K+.

Features of the adeno-associated virus origin involved in substrate recognition by the viral Rep protein

We previously demonstrated that the adeno-associated virus (AAV) Rep68 and Rep78 proteins are able to nick the AAV origin of DNA replication at the terminal resolution site (trs) in an ATP-dependent manner. Using four types of modified or mutant substrates, we now have investigated the substrate requirements of Rep68 in the trs endonuclease reaction. In the first kind of substrate, portions of the hairpinned AAV terminal repeat were deleted. Only deletions that retained virtually all of the small internal palindromes of the AAV terminal repeat were active in the endonuclease reaction. This result confirmed previous genetic and biochemical evidence that the secondary structure of the terminal repeat was an important feature for substrate recognition. In the second type of substrate, the trs was moved eight bases further away from the end of the genome. The mutant was nicked at a 50-fold-lower frequency relative to a wild-type origin, and the nick occurred at the correct trs sequence despite its new position. This finding indicated that the endonuclease reaction required a specific sequence at the trs in addition to the correct secondary structure. It also suggested that the minimum trs recognition sequence extended three bases from the cut site in the 3' direction. The third type of substrate harbored mismatched base pairs at the trs. The mismatch substrates contained a wild-type sequence on the strand normally cut but an incorrect sequence on the complementary strand. All of the mismatch mutants were capable of being nicked in the presence of ATP. However, there was substantial variation in the level of activity, suggesting that the sequence on the opposite strand may also be recognized during nicking. Analysis of the mismatch mutants also suggested that a single-stranded trs was a viable substrate for the enzyme. This interpretation was confirmed by analysis of the fourth type of substrate tested, which contained a single-stranded trs. This substrate was also cleaved efficiently by the enzyme provided that the correct strand was present in the substrate. In addition, the single-stranded substrate no longer required ATP as a cofactor for nicking. Finally, all of the substrates with mutant trss bound the Rep protein as efficiently as the wild-type did. This finding indicated that the sequence at the cut site was not involved in recognition of the terminal repeat for specific binding by the enzyme. We concluded that substrate recognition by the AAV Rep protein involves at least two and possibly as many as four features of the AAV terminal repeat.(ABSTRACT TRUNCATED AT 400 WORDS)