Tetramethylpyrazine attenuates renal tubular epithelial cell ferroptosis in contrast-induced nephropathy by inhibiting transferrin receptor and intracellular reactive oxygen species.

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI). Recently, ferroptosis was reported to be crucial for AKI pathogenesis. Our previous studies indicated antioxidant tetramethylpyrazine (TMP) prevent CIN in vivo. However, whether ferroptosis is involved in TMP nephroprotective mechanism against CIN is unclear. In the present study, we investigated the role of renal tubular epithelial cell ferroptosis in TMP reno-protective effect against CIN and the molecular mechanisms by which TMP regulates ferroptosis. Classical contrast-medium, Iohexol, was used to construct CIN models in rats and HK-2 cells. Results showed that tubular cell injury was accompanied by ferroptosis both in vivo and in vitro, including the typical features of ferroptosis, Fe2+ accumulation, lipid peroxidation and decreased glutathione peroxidase 4 (GPX4). Ferroptosis inhibition by classic inhibitors Fer-1 and DFO promoted cell viability and reduced intracellular ROS production. Additionally, TMP significantly inhibited renal dysfunction, reduced AKI biomarkers, prevented ROS production, inhibited renal Fe2+ accumulation and increased GPX4 expression. Expressions of various proteins associated with iron ion metabolism, including transferrin receptor (TFRC), divalent metal transporter 1, iron-responsive element binding protein 2, ferritin heavy chain 1, ferroportin 1, and heat shock factor binding protein 1, were examined using mechanistic analyses. Among these, TFRC changes were the most significant after TMP pretreatment. Results of siRNA knockdown and plasmid overexpression of TFRC indicated that TFRC is essential for TMP to alleviate ferroptosis and reduce LDH release, Fe2+ accumulation and intracellular ROS. Our findings provide crucial insights about the potential of TMP in treating AKI associated with ferroptosis.

H2O2 self-supplying and GSH-depleting nanosystem for amplified NIR mediated-chemodynamic therapy of MRSA biofilm-associated infections.

Reactive oxygen species (ROS) has emerged as potent therapeutic agents for biofilm-associated bacterial infections. Chemodynamic therapy (CDT), involving the generation of high-energy ROS, displays great potential in the therapy of bacterial infections. However, challenges such as insufficient hydrogen peroxide (H2O2) and over-expressed glutathione (GSH) levels within the microenvironment of bacterial biofilms severely limit the antibacterial efficacy of CDT. Herein, we have developed a multifunctional nanoplatform (CuS@CaO2@Dex) by integrating copper sulfide (CuS) and calcium peroxide (CaO2) into dextran (Dex)-coated nanoparticles. This innovative platform enhanced ROS generation for highly efficient biofilm elimination by simultaneously supplying H2O2 and depleting GSH. The Dex-coating facilitated the penetrability of CuS@CaO2@Dex into biofilms, while CaO2 generated a substantial amount of H2O2 in the acidic biofilm microenvironment. CuS, through a Fenton-like reaction, catalyzed the conversion of self-supplied H2O2 into hydroxyl radicals (•OH) and consumed the overexpressed GSH. Additionally, the incorporation of near-infrared II (NIR II) laser irradiation enhanced the photothermal properties of CuS, improving the catalytic efficiency of the Fenton-like reaction for enhanced antibacterial effects. In vivo experiments have demonstrated that CuS@CaO2@Dex exhibited remarkable antibacterial and antibiofilm efficacy, exceptional wound healing capabilities, and notable biosafety. In summary, the Dex-coated nanoplatform proposed in this study, with its self-sterilization capability through ROS, holds significant potential for future biomedical applications.

Bistatic Radar Cooperative Imaging Based on Complementary Random Waveform.

The cooperative imaging of the bistatic radar is an important research topic for missile-borne radar detection. The existing missile-borne radar detection system is mainly based on the target plot information separately extracted by each radar for data level fusion, without considering the gain brought by the cooperative processing of the radar target echo signal. In this paper, a random frequency-hopping waveform is designed for the bistatic radar to achieve efficient motion compensation. A coherent processing algorithm for bistatic echo signals is designed to achieve band fusion and improve the signal quality and range resolution of the radar. Simulation and high-frequency electromagnetic calculation data were used to verify the effectiveness of the proposed method.

Biomimetic Nanoplatelets to Target Delivery Hirudin for Site-Specific Photothermal/Photodynamic Thrombolysis and Preventing Venous Thrombus Formation.

Due to the high recurrence rate and mortality of venous thrombosis, there is an urgent need for research on antithrombotic strategies. Because of the short half-life, poor targeting capabilities, bleeding complications, and neurotoxic effects of conventional pharmacological thrombolysis methods, it is essential to develop an alternative strategy to noninvasive thrombolysis and decrease the recurrence rate of venous thrombosis. A platelet-mimetic porphyrin-based covalent organic framework-engineered melanin nanoplatform, to target delivery of hirudin to the vein thrombus site for noninvasive thrombolysis and effective anticoagulation, is first proposed. Owing to the thrombus-hosting properties of platelet membranes, the nanoplatform can target the thrombus site and then activate hyperthermia and reactive oxygen species for thrombolysis under near-infrared light irradiation. The photothermal therapy/photodynamic therapy combo can substantially improve the effectiveness (85.7%) of thrombolysis and prevent secondary embolism of larger fragments. Afterward, the highly loaded (97%) and slow-release hirudin (14 days) are effective in preventing the recurrence of blood clots without the danger of thrombocytopenia. The described biomimetic nanostructures offer a promising option for improving the efficacy of thrombolytic therapy and reducing the risk of bleeding complications in thrombus associated diseases.

Novel approach to enhance Bradyrhizobium diazoefficiens nodulation through continuous induction of ROS by manganese ferrite nanomaterials in soybean.

BACKGROUND: The study of symbiotic nitrogen fixation between (SNF) legumes and rhizobia has always been a hot frontier in scientific research. Nanotechnology provides a new strategy for biological nitrogen fixation research. However, how to construct abiotic nano-structure-biological system, using the special properties of nanomaterials, to realize the self-enhancement of biological nitrogen fixation capacity is important. RESULTS: In order to construct a more efficient SNF system, in this study, we applied manganese ferrite nanoparticles (MF-NPs) with sustainable diatomic catalysis to produce reactive oxygen species (ROS), thus regulating the nodulation pathway and increasing the number of nodules in soybean (Glycine max), eventually enhancing symbiotic nitrogen fixation. Symbiosis cultivation of MF-NPs and soybean plants resulted in 50.85% and 61.4% increase in nodule weight and number, respectively, thus inducing a 151.36% nitrogen fixation efficiency increase, finally leading to a 25.70% biomass accumulation increase despite no substantial effect on the nitrogenase activity per unit. Transcriptome sequencing analysis showed that of 36 differentially expressed genes (DEGs), 31 DEGs related to soybean nodulation were upregulated in late rhizobium inoculation stage (12 d), indicating that the increase of nodules was derived from nodule-related genes (Nod-R) continuous inductions by MF-NPs. CONCLUSIONS: Our results indicated that the nodule number could be effectively increased by extending the nodulation period without threatening the vegetative growth of plants or triggering the autoregulation of nodulation (AON) pathway. This study provides an effective strategy for induction of super-conventional nodulation.

Van-mediated self-aggregating photothermal agents combined with multifunctional magnetic nickel oxide nanoparticles for precise elimination of bacterial infections.

Building a novel and efficient photothermal antibacterial nanoplatform is a promising strategy for precise bacterial elimination. Herein, a nanocomposite NiO NPs@AuNPs@Van (NAV) for selective MRSA removal was constructed by electrostatic self-assembly of highly photothermal magnetic NiO NPs and vancomycin (Van)-modified gold nanoparticles (AuNPs). In the presence of MRSA and under NIR irradiation, Van-mediated AuNPs can self-aggregate on MRSA surface, generating photothermal effect in situ and killing 99.6% MRSA in conjunction with magnetic NiO NPs. Additionally, the photothermal efficiency can be improved by magnetic enrichment due to the excellent magnetism of NAV, thereby enhancing the bactericidal effect at a lower experimental dose. In vitro antibacterial experiments and full-thickness skin wound healing test demonstrated that this combination therapy could effectively accelerate wound healing in MRSA-infected mice, increase collagen coverage, reduce IL-6 and TNF-α content, and upregulate VEGF expression. Biological safety experiments confirmed that NAV has good biocompatibility in vivo and in vitro. Overall, this work reveals a new type of nanocomposite with enhanced photothermal antibacterial activity as a potential nano-antibacterial agent for treating bacteria-infected wounds.

Nontrivial Giant Linear Magnetoresistance in Nodal-Line Semimetal ZrGeSe 2D Layers.

Linear magnetoresistance (LMR) is usually observed in topological quantum materials and plausibly connected with the topologically nontrivial surface state with Dirac-cone-like linear dispersion because the frequently encountered large Hall resistivity can be trivially mixed into the LMR via charge inhomogeneity. Herein, by applying an optimal gate voltage to nodal-line semimetal ZrGeSe two-dimensional (2D) layers with specific thicknesses, we observe a giant nonsaturated LMR of 8 × 104% at 2 K and a magnetic field of 9 T. This giant LMR is accompanied by a very small Hall resistivity, which is inconsistent with the charge inhomogeneity mechanism. Our systematic results confirm that the giant LMR is maximized when the topological semimetal is in the "even-metal" regime and suppressed upon evolution to the normal "odd-metal" regime. The "even-to-odd" transition is universal regardless of the thicknesses of the crystals. A comparison with Abrikosov's quantum LMR theory indicates that the observed LMR cannot be trivial.

Efficient Gene Silencing in Intact Plant Cells Using siRNA Delivered By Functional Graphene Oxide Nanoparticles.

Delivery of small interfering RNA (siRNA) to intact plants for gene silencing mainly relies on viral vectors and Agrobacterium-mediated transformation due to the barrier of intact plant cell wall. Here, we reported that polymer functionalized graphene oxide nanoparticles (GONs) enable siRNA transfer into intact plant cells and bring about efficient gene silencing. We found that sheeted GONs could efficiently load siRNA to form small sized, near-spheroidal GONs-siRNA complex, which could be across the cell wall and internalize in the plant cell. The GONs-siRNA exhibited transient and strong silencing (97.2 % efficiency) in plant tissues at 24 h after treatment and returned to normal level at 5 days after treatment. This method has the obvious advantages of efficient, transient, simple, stability and well biocompatibility, which should greatly stimulate the application of nanomaterials as gene-engineering tools in plant research.

Gastric Acid Powered Nanomotors Release Antibiotics for In Vivo Treatment of Helicobacter pylori Infection.

Helicobacter pylori (H. pylori) infection has ≈75% probability of causing gastric cancer, so it is considered to be the strongest single risk factor for gastric malignancies. However, the harsh gastric acid environment has created obstacles to medical treatment. This work reports a nanomotor with a bottle-shaped container that can be loaded with small molecules of clarithromycin, nano calcium peroxide (CaO2 ), and Pt nanoparticles (Pt NPs) by ultrasound. Nanomotors can quickly consume gastric acid through the chemical reaction of CaO2 to temporarily neutralize gastric acid. The product hydrogen peroxide (H2 O2 ) is catalytically decomposed into a large amount of oxygen (O2 ) by Pt NPs. The local concentration gradient of O2 bubbles causes it to be expelled from the nanobottles through a narrow opening, and then push the nanobottles forward to provide maximum release and prodrug efficacy. Experiments in animal models show that 15 mg nanomotors can safely and quickly neutralize gastric acid in the stomach and simultaneously release prodrugs to achieve good therapeutic effects without causing acute toxicity. H. pylori burden in mice was 2.6 orders of magnitude lower than that in the control group. The stomach returns to normal pH within 1 d after administration.

Reversible engineering of topological insulator surface state conductivity through optical excitation.

Despite the broadband response, limited optical absorption at a particular wavelength hinders the development of optoelectronics based on Dirac fermions. Heterostructures of graphene and various semiconductors have been explored for this purpose, while non-ideal interfaces often limit the performance. The topological insulator (TI) is a natural hybrid system, with the surface states hosting high-mobility Dirac fermions and the small-bandgap semiconducting bulk state strongly absorbing light. In this work, we show a large photocurrent response from a field effect transistor device based on intrinsic TI Sn-Bi1.1Sb0.9Te2S (Sn-BSTS). The photocurrent response is non-volatile and sensitively depends on the initial Fermi energy of the surface state, and it can be erased by controlling the gate voltage. Our observations can be explained with a remote photo-doping mechanism, in which the light excites the defects in the bulk and frees the localized carriers to the surface state. This photodoping modulates the surface state conductivity without compromising the mobility, and it also significantly modify the quantum Hall effect of the surface state. Our work thus illustrates a route to reversibly manipulate the surface states through optical excitation, shedding light into utilizing topological surface states for quantum optoelectronics.

Pomegranate-Inspired Silica Nanotags Enable Sensitive Dual-Modal Detection of Rabies Virus Nucleoprotein.

The outbreak of rabies virus (RABV) in Asia and Africa has attracted widespread concern due to its 100% mortality rate, and RABV detection is crucial to its diagnosis and treatment. Herein, we report a sensitive and reliable strategy for the dual-modal RABV detection using pomegranate-shaped dendritic silica nanospheres fabricated with densely incorporated quantum dots (QDs) and horseradish peroxidase (HRP)-labeled antibody. The immunoassay involves the specific interaction between virus and nanospheres-conjugated antibody coupled with robust fluorescence signal originating from QDs and naked-eye discernible colorimetric signal on the oxTMB. The ultrahigh loading capacity of QDs enables the detection limit down to 8 pg/mL via fluorescence modality, a 348-fold improvement as compared with conventional enzyme-linked immunosorbent assay (ELISA). In addition, the detection range was from 1.20 × 102 to 2.34 × 104 pg/mL by plotting the absorbance at 652 nm with RABV concentrations with a detection limit of 91 pg/mL, which is nearly 2 order of magnitude lower than that of the conventional ELISA. Validated with 12 brain tissue samples, our immunoassay results are completely consistent with polymerase chain reaction (PCR) results. Compared with the PCR assay, our approach requires no complex sample pretreatments or expensive instruments. This is the first report on RABV diagnosis using nanomaterials for colorimetry-based prescreening and fluorescence-based quantitative detection, which may pave the way for virus-related disease diagnosis and clinical analysis.

Visible light mediated oxidative lactonization of 2-methyl-1,1'-biaryls for the synthesis of benzocoumarins.

A visible light mediated oxidative lactonization of 2-methyl-1,1'-biaryls was developed, giving benzocoumarins in good yields. The reaction features multiple C-H functionalization processes with oxygen as the final oxidant. The corresponding 2-aldehdyes, alcohols and carboxylic acids of the 1,1'-biaryls also worked well for the reaction.

N-Heterocyclic Carbene-Catalyzed Annulation of α-Chloroaldehydes with γ-/δ-Amino-α,ß-Unsaturated Ketones: Enantioselective Synthesis of Pyrrolidones and Piperidones.

The N-heterocyclic carbene-catalyzed [2+3] and [2+4] annulations of α-chloroaldehydes with γ-/δ-amino-α,ß-unsaturated ketones were developed, giving the corresponding pyrrolidones and piperidones in good yields with exclusive trans-selectivities and excellent enantioselectivities.

Diastereo- and Enantioselective Synthesis of Spirooxindoles with Contiguous Tetrasubstituted Stereocenters via Catalytic Coupling of Two Tertiary Radicals.

The oxidative N-heterocyclic carbene-catalyzed [3 + 2] annulation of ß,ß-disubstituted enals and dioxindoles was developed, giving the spirocyclic oxindole-γ-lactones bearing two contiguous tetrasubstituted stereocenters in good yields with excellent diastereoselectivities and good enantioselectivities.

Visible light promoted coupling of alkynyl bromides and Hantzsch esters for the synthesis of internal alkynes.

A metal-free visible light promoted C(sp3)-C(sp) coupling reaction of alkynyl bromides and Hantzsch esters was developed, giving internal alkynes with primary, secondary, tertiary alkyl or other functional groups in good to high yields.

Degradation and detoxification of azo dyes by a salt-tolerant yeast Cyberlindnera samutprakarnensis S4 under high-salt conditions.

A new yeast strain which was capable of degrading various azo dyes under high-salt conditions was identified in this study. The results showed that the yeast named S4 was identified as Cyberlindnera samutprakarnensis through 26S rDNA sequence analysis and could decolorize more than 97% of Acid Red B (ARB) within 18 h under the optimal conditions. The acute toxicity of ARB sharply decreased after degradation. NADH-DCIP reductase and lignin peroxidase were determined as the key reductase and oxidase of the yeast S4, respectively. Furthermore, it was proposed that ARB was degraded by strain S4 successively through reduction of azo bonds, hydroxylation, deamination, desulfonation and finally to the TCA cycle.

Mineralized State of the Avian Influenza Virus in the Environment.

Although the circulation of avian influenza viruses in humans is limited, they can be transmitted from Aves (birds) to humans, representing a great challenge. Herein, we suggest that influenza viruses from Aves might exist in a mineralized state owing to the high calcium concentrations in the avian intestine. Using two typical influenza viruses as examples, we demonstrate that these viruses can self-mineralize in simulated avian intestinal fluid, resulting in egg-like virus-mineral structured composites. The mineralized viruses are more robust, with enhanced infectivity and thermostability. More importantly, the mineral exterior of mineralized viruses can alter their cell internalization, expanding the possible tropisms. The discovery of a mineralized state of influenza viruses highlights the integration of nanomaterials and viruses in the environment, which provides a new understanding of avian influenza infection and its control.

Virus capture and destruction by label-free graphene oxide for detection and disinfection applications.

Graphene oxide (GO) can efficiently capture viruses, destroy their surface proteins, and extract viral RNA in an aqueous environment by using the superficial bioreduction of GO. It follows from these phenomena that GO is an excellent nanomaterial for the high-throughput detection and disinfection of viruses, demonstrating its great potential for the prevention of environmental infections.

Dynamic investigation of nutrient consumption and injection strategy in microbial enhanced oil recovery (MEOR) by means of large-scale experiments.

Microbial enhanced oil recovery (MEOR) depends on the in situ microbial activity to release trapped oil in reservoirs. In practice, undesired consumption is a universal phenomenon but cannot be observed effectively in small-scale physical simulations due to the scale effect. The present paper investigates the dynamics of oil recovery, biomass and nutrient consumption in a series of flooding experiments in a dedicated large-scale sand-pack column. First, control experiments of nutrient transportation with and without microbial consumption were conducted, which characterized the nutrient loss during transportation. Then, a standard microbial flooding experiment was performed recovering additional oil (4.9 % Original Oil in Place, OOIP), during which microbial activity mostly occurred upstream, where oil saturation declined earlier and steeper than downstream in the column. Subsequently, more oil remained downstream due to nutrient shortage. Finally, further research was conducted to enhance the ultimate recovery by optimizing the injection strategy. An extra 3.5 % OOIP was recovered when the nutrients were injected in the middle of the column, and another additional 11.9 % OOIP were recovered by altering the timing of nutrient injection.