Atomically Thin Kagome-Structured Co9Te16 Achieved through Self-Intercalation and Its Flat Band Visualization.

Kagome materials have recently garnered substantial attention due to the intrinsic flat band feature and the stimulated magnetic and spin-related many-body physics. In contrast to their bulk counterparts, two-dimensional (2D) kagome materials feature more distinct kagome bands, beneficial for exploring novel quantum phenomena. Herein, we report the direct synthesis of an ultrathin kagome-structured Co-telluride (Co9Te16) via a molecular beam epitaxy (MBE) route and clarify its formation mechanism from the Co-intercalation in the 1T-CoTe2 layers. More significantly, we unveil the flat band states in the ultrathin Co9Te16 and identify the real-space localization of the flat band states by in situ scanning tunneling microscopy/spectroscopy (STM/STS) combined with first-principles calculations. A ferrimagnetic order is also predicted in kagome-Co9Te16. This work should provide a novel route for the direct synthesis of ultrathin kagome materials via a metal self-intercalation route, which should shed light on the exploration of the intriguing flat band physics in the related systems.

Hydrogen-Bond-Mediated Formation of C-N or C=N Bond during Photocatalytic Reductive Coupling Reaction over CdS Nanosheets.

Reductive amination of carbonyl compounds and nitro compounds represents a straightforward way to attain imines or secondary amines, but it is difficult to control the product selectivity. Herein, we report the selective formation of C-N or C=N bond readily manipulated through a solvent-induced hydrogen bond bridge, facilitating the swift photocatalytic reductive coupling process. The reductive-coupling of nitro compounds with carbonyl compounds using formic acid and sodium formate as the hydrogen donors over CdS nanosheets selectively generates imines with C=N bonds in acetonitrile solvent; while taking methanol as solvent, the C=N bonds are readily hydrogenated to the C-N bonds via hydrogen-bonding activation. Experimental and theoretical study reveals that the building of the hydrogen-bond bridge between the hydroxyl groups in methanol and the N atoms of the C=N motifs in imines facilitates the transfer of hydrogen atoms from CdS surface to the N atoms in imines upon illumination, resulting in the rapid hydrogenation of the C=N bonds to give rise to the secondary amines with C-N bonds. Our method provides a simple way to control product selectivity by altering the solvents in photocatalytic organic transformations.

Manganese Carbodiimide (MnNCN): A New Heterogeneous Mn Catalyst for the Selective Synthesis of Nitriles from Alcohols.

Earth-abundant manganese oxides (MnOx) were competitive candidates when screening catalysts for ammoxidation of alcohols into nitriles due to their redox property. However, over-oxidation and possible acid-catalyzed hydrolysis of nitriles into amides still limited the application of MnOx in nitrile synthesis. In this work, manganese carbodiimide (MnNCN) was first reported to be robust for the ammoxidation of alcohols into nitriles, avoiding over-oxidation and the hydrolysis. Besides the high activity and selectivity, MnNCN demonstrated wide substrate scope including the ammoxidation of primary alcohols into nitriles, the oxidative C-C bonds cleavage and ammoxidation of secondary alcohols, phenyl substituted aliphatic alcohols, and diols into nitriles. Controlled experiments and DFT calculation results revealed that the excellent catalytic performance of MnNCN originated from its high ability in the activation of O2 molecules, and favorable oxidative dehydrogenation of C=N bonds in the aldimine intermediates (RCH=NH) into nitriles, inhibiting the competitive side reaction of the oxidation of aldehydes into carboxylic acids, followed to amide byproducts. Moreover, the hydrolysis of nitriles was also inhibited over MnNCN for its weak acidity as compared with MnOx. This study provided new insights into Mn-catalyzed aerobic oxidations as a highly important complement to manganese oxides.

Synergy of Oxygen Vacancies and Base Sites for Transfer Hydrogenation of Nitroarenes on Ceria Nanorods.

CeO2 nanorod based catalysts for the base-free synthesis of azoxy-aromatics via transfer hydrogenation of nitroarenes with ethanol as hydrogen donor have been synthesized and investigated. The oxygen vacancies (Ov ) and base sites are critical for their excellent catalytic properties. The Ov , i.e., undercoordinated Ce cations, serve as the sites to activate ethanol and nitroarenes by lowering the energy barrier to transfer hydrogen from α-Csp3 -H in ethanol to the nitro group coupling it to the redox reactions between Ce3+ and Ce4+ . At the same time, the base sites catalyze the condensation step to selectively produce azoxy-aromatics. The catalytic route opens a much improved way to use non-noble metal oxides without additives for the selective functional group reduction and coupling reactions.

Oxygen Vacancy-Induced Metal-Support Interactions in AuPd/ZrO2 Catalysts for Boosting 5-Hydroxymethylfurfural Oxidation.

The construction of strong metal-support interactions in oxide-supported noble metal nanocatalysts has been considered an emerging and efficient way in improving catalytic performance in biomass-upgrading reactions. Herein, a citric acid (CA)-assisted synthesized ZrO2 layer with improved oxygen vacancy (Ov) concentrations on a natural clay mineral of halloysite nanotubes (HNTs) was designed. Moreover, AuxPdy/ZrO2@HNTs-zCA catalysts were prepared by loading AuPd bimetal and employed for aerobic oxidation of the lignocellulosic biomass-derived 5-hydroxymethylfurfural (HMF) platform to the bioplastic monomer 2,5-furandicarboxylic acid (FDCA) with water as the solvent. The results of catalytic experiments revealed that the Au3Pd1/ZrO2@HNTs-1.0CA catalyst exhibited excellent catalytic activity at 0.5 MPa O2, with a satisfactory FDCA yield of 99.5% and outstanding FDCA formation rate of 1057.9 mmol·g-1·h-1. The improved Ov concentration in the ZrO2 support enhanced the adsorption and activation ability of the catalyst for O2, and a higher Lewis acid concentration provided a stronger adsorption ability of the catalyst for reaction substrates. Besides, the synergistic effect of AuPd bimetallic nanoparticles steered the tandem oxidation of aldehyde and alcohol groups in HMF and accelerated the rate-determining step. More importantly, the relationship between the Ov concentration and catalytic performance also demonstrated that the enhanced catalytic activity for HMF oxidation was mainly attributed to the active interface of AuPd-ZrOx. This work offers fresh insights into rationally designing oxygen vacancy-driven strong interactions between the oxide support and noble nanoparticles for the catalytic upgrade of biomass platform chemicals.

Unexpected higher corrosion in the gas phase region of metals caused by calcium and magnesium ions compared to sodium ions.

In the marine environment, Na+ ions have been the focus of attention owing to their high content, which is one of the important factors causing marine corrosion. With reference to the content of macro ions in seawater, circular iron samples were semi-immersed in 0.04 M MgCl2 and 0.6 M NaCl solutions containing different proportions of ethanol. Unexpectedly, we observed more severe corrosion effects in the gas phase region and at the gas-liquid interface of metal samples semi-immersed in the MgCl2 solution. Although the concentration of the MgCl2 solution was only 1/15 of that of the NaCl solution, the iron corrosion induced by MgCl2 was significantly more severe than that caused by NaCl when the ethanol content was increased. Mg2+ ions outperform Na+ ions in metal gas phase corrosion. Especially in the oxygen content of the gas phase corrosion product, MgCl2 caused an increase by up to 52.7%, while NaCl only resulted in a 10.3% increase. Ethanol is normally regarded as a corrosion inhibitor and exists in the liquid phase. Interestingly, in the gas phase and at the gas-liquid interface, ethanol aggravated rather than reducing iron corrosion, particularly in the presence of Mg2+ ions. In addition, we observed that Ca2+ ions produced more severe corrosion effects.

Deep Learning-Aided Modulation Recognition for Non-Orthogonal Signals.

Automatic Modulation Recognition (AMR) can obtain the modulation mode of the received signal for subsequent processing without the assistance of the transmitter. Although the existing AMR methods have been mature for the orthogonal signals, these methods face challenges when deployed in non-orthogonal transmission systems due to the superimposed signals. In this paper, we aim to develop efficient AMR methods for both downlink and uplink non-orthogonal transmission signals using deep learning-based data-driven classification methodology. Specifically, for downlink non-orthogonal signals, we propose a Bi-directional Long Short-Term Memory (BiLSTM)-based AMR method that exploits long-term data dependence to automatically learn irregular signal constellation shapes. Transfer learning is further incorporated to improve recognition accuracy and robustness under varying transmission conditions. For uplink non-orthogonal signals, the combinatorial number of classification types explodes exponentially with the number of signal layers, which becomes the major obstacle to AMR. We develop a spatio-temporal fusion network based on the attention mechanism to efficiently extract spatio-temporal features, and network details are optimized according to the superposition characteristics of non-orthogonal signals. Experiments show that the proposed deep learning-based methods outperform their conventional counterparts in both downlink and uplink non-orthogonal systems. In a typical uplink scenario with three non-orthogonal signal layers, the recognition accuracy can approach 96.6% in the Gaussian channel, which is 19% higher than the vanilla Convolution Neural Network.

In Vitro Anti-Tumor and Hypoglycemic Effects of Total Flavonoids from Willow Buds.

Salix babylonica L. is a species of willow tree that is widely cultivated worldwide as an ornamental plant, but its medicinal resources have not yet been reasonably developed or utilized. Herein, we extracted and purified the total flavonoids from willow buds (PTFW) for component analysis in order to evaluate their in vitro anti-tumor and hypoglycemic activities. Through Q-Orbitrap LC-MS/MS analysis, a total of 10 flavonoid compounds were identified (including flavones, flavan-3-ols, and flavonols). The inhibitory effects of PTFW on the proliferation of cervical cancer HeLa cells, colon cancer HT-29 cells, and breast cancer MCF7 cells were evaluated using an MTT assay. Moreover, the hypoglycemic activity of PTFW was determined by investigating the inhibitory effects of PTFW on α-amylase and α-glucosidase. The results indicated that PTFW significantly suppressed the proliferation of HeLa cells, HT-29 cells, and MCF7 cells, with IC50 values of 1.432, 0.3476, and 2.297 mg/mL, respectively. PTFW, at different concentrations, had certain inhibitory effects on α-amylase and α-glucosidase, with IC50 values of 2.94 mg/mL and 1.87 mg/mL, respectively. In conclusion, PTFW at different doses exhibits anti-proliferation effects on all three types of cancer cells, particularly on HT-29 cells, and also shows significant hypoglycemic effects. Willow buds have the potential to be used in functional food and pharmaceutical industries.

Selective Electrochemical Hydrogenation of Phenol with Earth-abundant Ni-MoO2 Heterostructured Catalysts: Effect of Oxygen Vacancy on Product Selectivity.

Herein, we report highly efficient carbon supported Ni-MoO2 heterostructured catalysts for the electrochemical hydrogenation (ECH) of phenol in 0.10 M aqueous sulfuric acid (pH 0.7) at 60 °C. Highest yields for cyclohexanol and cyclohexanone of 95 % and 86 % with faradaic efficiencies of ∼50 % are obtained with catalysts bearing high and low densities of oxygen vacancy (Ov ) sites, respectively. In situ diffuse reflectance infrared spectroscopy and density functional theory calculations reveal that the enhanced phenol adsorption strength is responsible for the superior catalytic efficiency. Furthermore, 1-cyclohexene-1-ol is an important intermediate. Its hydrogenation route and hence the final product are affected by the Ov density. This work opens a promising avenue to the rational design of advanced electrocatalysts for the upgrading of phenolic compounds.

High Nitrile Yields of Aerobic Ammoxidation of Alcohols Achieved by Generating •O2- and Br• Radicals over Iron-Modified TiO2 Photocatalysts.

Catalytic ammoxidation of alcohols into nitriles is an essential reaction in organic synthesis. While highly desirable, conducting the synthesis at room temperature is challenging, using NH3 as the nitrogen source, O2 as the oxidant, and a catalyst without noble metals. Herein, we report robust photocatalysts consisting of Fe(III)-modified titanium dioxide (Fe/TiO2) for ammoxidation reactions at room temperature utilizing oxygen at atmospheric pressure, NH3 as the nitrogen source, and NH4Br as an additive. To the best of our knowledge, this is the first example of catalytic ammoxidation of alcohols over a photocatalyst using such cheap and benign materials. Various (hetero) aromatic nitriles were synthesized at high yields, and aliphatic alcohols could also be transformed into corresponding nitriles at considerable yields. The modification of TiO2 with Fe(III) facilitates the formation of active •O2- radicals and increases the adsorption of NH3 and amino intermediates on the catalyst, accelerating the ammoxidation to yield nitriles. The additive NH4Br impressively improves the catalytic efficiency via the formation of bromine radicals (Br•) from Br-, which works synergistically with •O2- to capture H• from Cα-H, which is present in benzyl alcohol and the intermediate aldimine (RCH═NH), to generate the active carbon-centered radicals. Further, the generation of Br• from the Br- additive consumes the photogenerated holes and OH• radicals to prevent over-oxidation, significantly improving the selectivity toward nitriles. This amalgamation of function and synergy of the Fe(III)-doped TiO2 and NH4Br reveals new opportunities for developing semiconductor-based photocatalytic systems for fine chemical synthesis.

Nocardioides ochotonae sp. nov., Nocardioides campestrisoli sp. nov. and Nocardioides pantholopis sp. nov., isolated from the Qinghai-Tibet Plateau.

Six Gram-stain-positive, aerobic and irregular-rod-shaped actinobacteria (ZJ1313T, ZJ1307, MC1495T, Y192, 603T and X2025) were isolated from the Qinghai-Tibet Plateau of China and were characterized using a polyphasic taxonomic method. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the six new strains formed three distinct clusters within the genus Nocardioides, and strains ZJ1313T and ZJ1307 were most closely related to N. solisilvae JCM 31492T (16S rRNA gene sequence similarity, 98.0 %), MC1495T and Y192 to N. houyundeii 78T (98.5 %), and 603T and X2025 to N. dokdonensis JCM 14815T (97.6 %). The digital DNA-DNA hybridization values of strains ZJ1313T, MC1495T and 603T among each other and with type strains of their closest relatives were all below the 70 % cut-off point, but values within each pair of new strains were all higher than the threshold. The major fatty acids of these strains were iso-C16 : 0, C17 : 1 ω8c or C18 : 1 ω9c. MK-8(H4) was the predominant respiratory menaquinone and ʟʟ-2,6-diaminopimelic acid was the diagnostic diamino acid. All the strains shared diphosphatidylglycerol (predominant), phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol as the common polar lipids, with minor difference in the types of unidentified phospholipids, glycolipids and lipids. The G+C contents based on genomic DNA of strains ZJ1313T, MC1495T and 603T were 72.5, 72.1 and 73.2 mol%, respectively. The above results suggested that strain pairs ZJ1313T/ZJ1307, MC1495T/Y192 and 603T/X2025 represent three new species of genus Nocardioides, for which the names Nocardioides ochotonae sp. nov. (ZJ1313T=GDMCC 4.177T=KCTC 49537T=JCM 34185T), Nocardioides campestrisoli sp. nov. (MC1495T=GDMCC 4.176T=KCTC 49536T=JCM 34307T) and Nocardioides pantholopis sp. nov. (603T=CGMCC 4.7510T=DSM 106494T) are proposed accordingly.

Luteolin increases susceptibility to macrolides by inhibiting MsrA efflux pump in Trueperella pyogenes.

Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen associated with a variety of diseases in many domestic animals. Therapeutic treatment options for T. pyogenes infections are becoming limited due to antimicrobial resistance, in which efflux pumps play an important role. This study aims to evaluate the inhibitory activity of luteolin, a natural flavonoid, on the MsrA efflux pump and investigate its mechanism. The results of antimicrobial susceptibility testing indicated that the susceptibility of msrA-positive T. pyogenes isolates to six macrolides increased after luteolin treatment, while the susceptibility of msrA-negative isolates showed no change after luteolin treatment. It is suspected that luteolin may increase the susceptibility of T. pyogenes isolates by inhibiting MsrA activity. After 1/2 MIC luteolin treatment for 36 h, the transcription level of the msrA gene and the expression level of the MsrA protein decreased by 55.0-97.7% and 36.5-71.5%, respectively. The results of an affinity test showed that the equilibrium dissociation constant (KD) of luteolin and MsrA was 6.462 × 10-5 M, and hydrogen bonding was predominant in the interaction of luteolin and MsrA. Luteolin may inhibit the ATPase activity of the MsrA protein, resulting in its lack of an energy source. The current study illustrates the effect of luteolin on MsrA in T. pyogenes isolates and provides insight into the development of luteolin as an innovative agent in combating infections caused by antimicrobial-resistant bacteria.

Molecular Basis for Luteolin as a Natural TatD DNase Inhibitor in Trueperella pyogenes.

TatD960 and TatD825 are DNases that contribute to biofilm formation and virulence in Trueperella pyogenes (T. pyogenes). Luteolin is a natural flavonoid commonly found in plants that exhibits antimicrobial capacity. Our study aims to investigate the effects of luteolin on TatD DNases as a natural inhibitor. In this research, the expression of tatD genes and TatD proteins in T. pyogenes treated with luteolin was detected, and then the effect of luteolin on the hydrolysis of DNA by TatD DNases was analyzed using agarose gel electrophoresis. Moreover, the interactions between luteolin and TatD DNases were tested using surface plasmon resonance (SPR) assays and molecular docking analysis. After 1/2 MIC luteolin treatment, the transcription of tatD genes and expression of TatD proteins appeared to be reduced in 80-90% of T. pyogenes (n = 20). The gel assay revealed that luteolin can inhibit the activity of TatD DNases. The SPR assay showed that the KD values of luteolin to TatD960 and TatD825 were 6.268 × 10-6 M and 5.654 × 10-6 M, respectively. We found through molecular docking that hydrogen bonding is predominant in the interaction of luteolin and TatD DNases. Our data indicate that luteolin inhibited the ability of TatD DNases by decreasing their binding to DNA. The current study provides an insight into the development of luteolin as a DNase inhibitor in preventing biofilm formation and virulence in T. pyogenes.

Effects of Luteolin on Biofilm of Trueperella pyogenes and Its Therapeutic Effect on Rat Endometritis.

Trueperella pyogenes is an opportunistic pathogen that causes suppurative infections in animals. The development of new anti-biofilm drugs will improve the current treatment status for controlling T. pyogenes infections in the animal husbandry industry. Luteolin is a naturally derived flavonoid compound with antibacterial properties. In this study, the effects and the mechanism of luteolin on T. pyogenes biofilm were analyzed and explored. The MBIC and MBEC of luteolin on T. pyogenes were 156 µg/mL and 312 µg/mL, respectively. The anti-biofilm effects of luteolin were also observed by a confocal laser microscope and scanning electron microscope. The results indicated that 312 µg/mL of luteolin could disperse large pieces of biofilm into small clusters after 8 h of treatment. According to the real-time quantitative PCR detection results, luteolin could significantly inhibit the relative expression of the biofilm-associated genes luxS, plo, rbsB and lsrB. In addition, the in vivo anti-biofilm activity of luteolin against T. pyogenes was studied using a rat endometritis model established by glacial acetic acid stimulation and T. pyogenes intrauterine infusion. Our study showed that luteolin could significantly reduce the symptoms of rat endometritis. These data may provide new opinions on the clinical treatment of luteolin and other flavonoid compounds on T. pyogenes biofilm-associated infections.

In Vitro Biosensing of ß-Amyloid Peptide Aggregation Dynamics using a Biological Nanopore.

Alzheimer's disease and other neurodegenerative disorders are becoming more prevalent as advances in technology and medicine increase living standards and life expectancy. Alzheimer's disease is thought to initiate development early in the patient's life and progresses continuously into old age. This process is characterized molecularly by the amyloid hypothesis, which asserts that self-aggregating amyloid peptides are core to the pathophysiology in Alzheimer's progression. Precise quantification of amyloid peptides in human bodily fluid samples (i.e. cerebrospinal fluid, blood) may inform diagnosis and prognosis, and has been studied using established biosensing technologies like liquid chromatography, mass spectrometry, and immunoassays. However, existing methods are challenged to provide single molecule, quantitative analysis of the disease-causing aggregation process. Ultra-sensitive nanopore biosensors can step in to fill this role as a dynamic mapping tool. The work in this paper establishes characteristic signals of ß-amyloid 40 monomers, oligomers, and soluble aggregates, as well as a proof-of-concept foundation where a biological nanopore biosensor is used to monitor the extent of in vitro ß-amyloid 40 peptide aggregation at the single molecule level. This foundation allows for future work to expand in drug screening, diagnostics, and aggregation dynamic experiments.

Influence of tillage practices on phosphorus forms in aggregates of Mollisols from northeast China.

BACKGROUND: Phosphorus (P) is an essential mineral nutrient for crop growth and development. Much remains unknown regarding the content and distribution of P forms in different soil aggregates as affected by tillage practices. A 3-year field experiment was conducted to investigate the effects of no-tillage (NT), rotary tillage (RT), subsoiling (SS), and deep tillage (DT) on soil aggregate distribution pattern, aggregate-associated P content, and to understand the conversion trend. RESULTS: Tillage has the potential to accelerate the processes in transforming macro-aggregates (> 0.25 mm) into micro-aggregates (< 0.25 mm). Greatest aggregate stability was attained under RT. Total phosphorus (TP) and available phosphorus (AP) under NT were increased by 21.1-82.0% in contrast to other tillage treatments. The NT had high content in inorganic phosphorus (IP), aluminum phosphorus (Al-P), and iron phosphorus (Fe-P) with 416.7, 107.9, and 99.1 mg·kg-1 on average, respectively. Aggregates with a size dimension of < 2 mm were more sensitive than other sizes of aggregates. IP was evenly distributed throughout all aggregates, ranging from 336.3 to 430.6 mg kg-1 . No differences in organic phosphorus (OP) were found in all tillage treatments, while NT promoted the transformation of labile OP to IP. The AP and OP were generally more abundant in aggregates of 2 to 0.25 mm and < 0.25 mm. CONCLUSION: Short-term NT can improve soil structure and increase P reserves, thus, enhancing the conversion of P from being scarce to available. © 2021 Society of Chemical Industry.

Response surface optimization and antioxidant activity of total proanthocyanidins fraction from Abutilon theophrasti Medic. leaves.

The extraction procedure and antioxidant activity were investigated for total proanthocyanidins extracts from Abutilon theophrasti Medic. leaves collected in August, September and October. The maximum extraction yield was achieved with 90% ethanol, 80°C of heating reflux temperature, 149.94 min of extraction time and 60(ml/g) of the ratio of solvent and material, which were optimized by Box-Behnken Design of response surface method. Spectrophotometric study displayed that total proanthocyanidins content was (0.44±0.02)% (0.52±0.01)% and (0.59±0.01)% for August, September and October samples, respectively. The proanthocyanidins extracts exhibited much stronger antioxidant activity to scavenge ABTS and DPPH free radicals, and reduce ferric power than the control synthetic antioxidant BHT. The present findings suggest that the proanthocyanidins extract from Abutilon theophrasti Medic. leaves was a very interesting candidate for the research and development of natural and healthy antioxidant for the pharmaceutical and food industries.

Enhanced Sensitivity in Nanopore Sensing of Cancer Biomarkers in Human Blood via Click Chemistry.

Cancer biomarkers are expected to be indicative of the occurrence of certain cancer diseases before the tumors form and metastasize. However, many biomarkers can only be acquired in extremely low concentrations, which are often beyond the limit of detection (LOD) of current instruments and technologies. A practical strategy for nanopore sensing of cancer biomarkers in raw human blood down to the femtomolar level is developed here. This strategy first converts the detection of cancer biomarkers to the quantification of copper ions by conducting a sandwich assay involving copper oxide nanoparticles. The released Cu2+ is then taken to catalyze the "click" reaction which ligates a host-guest modified DNA probe. Finally, this DNA probe is subjected to single-channel recordings to afford the translocation events that can be used to derive the concentrations of the original biomarkers. Due to the amplification effects of nanoparticle loadings and the "click" reaction, the LOD of this strategy can be as low as the subfemtomolar level. Further, the acid treatment step could effectively eliminate the interferences from plasma proteins in raw human blood and make the strategy highly suitable for the detection of cancer biomarkers in clinical samples.

Enterococcal isolates from bovine subclinical and clinical mastitis: Antimicrobial resistance and integron-gene cassette distribution.

Bovine mastitis is one of the most prevalent and costly diseases, and can be caused by a variety of bacterial pathogens including enterococci. Unfortunately, comprehensive studies about the prevalence and antimicrobial resistance profiles of entercocci are scarcely reported. This study aimed to investigate the occurrence of enterococci associated with bovine clinical mastitis and subclinical mastitis, to assess their antimicrobial resistance profiles, and to detect the distribution of integrons and gene cassette arrays in Liaoning of China. Our results indicated subclinical mastitis occurred in 34.3% of bovine, and 21.4% of bovine were positive for clinical mastitis, meanwhile Enterococcus faecium is the predominant pathogen in both clinical mastitis and subclinical mastitis. More than 50% of the total isolates were resistant to penicillin, ceftiofur, tylosin, lincomycin, and oxytetracycline. Class I integrons was detected in enterococcal isolates from both clinical and subclinical mastitis with 57.1% and 45.3%, respectively. Meanwhile, class II integrons only were observed in enterococcal isolates from subclinical mastitis. Multidrug resistance has become prevalent in enterococci isolated from clinical mastitis and subclinical mastitis in Liaoning, northeast of China. This study revealed that enterococcal isolates had shown resistant to ß-lactam antibiotics including penicillin, and different therapeutic programs should be carried out in Liaoning of China.

Extraction technology, component analysis, and in vitro antioxidant and antibacterial activities of total flavonoids and fatty acids from Tribulus terrestris L. fruits.

The current study focused on the extraction technology, components analysis, in vitro antioxidant and antibacterial activities of total flavonoids and fatty acids from Tribulus terrestris L. fruits. The extraction process of total flavonoids and fatty acids was optimized by the response surface method, and the compositions were identified from the two extracts by HPLC-DAD-ESI-MS- and GC-MS, respectively. In addition, the antioxidant and antibacterial activities were evaluated by assay of ABTS, DPPH radical scavenging activity, ferric reducing antioxidant power and minimal inhibitory concentration. The yields of total flavonoids and fatty acids were 0.46 and 9.76% under the optimized conditions. Moreover, nine and eight compositions were identified from the two extracts based on the related references, respectively. In addition, total flavonoids and fatty acids extracts both exhibited certain antioxidant and antibacterial activities. The present findings suggest that total flavonoids extracted from T. terrestris L. fruits comprised a more interesting candidate than fatty acids for the research and development of natural and healthy antioxidants and antibacterial agents for the pharmaceutical and food industries.