The linear syzygy graph of a monomial ideal and linear resolutions

Czechoslovak Mathematical Journal - for each squarefree monomial ideal I ? S = k[x1, …, xn], we associate a simple finite graph GI by using the first linear syzygies of I. The nodes of...     

Nafion?NR50 catalyzed A3-coupling for the synthesis of propargylamines via C-H activation

A one-pot, three-component coupling reaction of aldehydes, amines and alkyne (A³-coupling) via C-H activation using perflorinated resinsulphonic acid (Nafion?NR50) as a recyclable and environmentally benign catalyst for the synthesis of propargylamine derivatives is described. This protocol avoids the use of heavy metals, co-catalysts and produces the propargylamines in excellent yields.     

Coagulansins A and B,New Withanolides from Withania coagulans Dunal

Coagulansins A ( 1 ) and B ( 2 ), two new withanolides, were isolated from the CHCl₃‐soluble fraction of Withania coagulans Dunal , along with two known withanolides, coagulin R and withanolide P. Their structures were assigned by means of ¹H‐ and ¹³C‐NMR spectra, DEPT, and ¹H,¹H‐COSY, NOESY, HMQC, and HMBC experiments.     

Electrocatalytic oxidation of thiosulfate at2,7-bis(ferrocenylethyl)-fluoren-9-one-modified carbon paste electrode(2,7-BFEFMCPE): Application to the catalytic determination of thiosulfate in real sample

<正>Electrocatalytic oxidation of thiosulfate at the 2,7-BFEFMCPE occurs at a potential about 460 mV less positive than that unmodified carbon paste electrode.The diffusion coefficient(=5.6×10~(-5) cm~2 s~(-1)),the kinetic parameters such as electron transfer coefficient,(=0.5) and k_h(=1.21×10~(-3) cm s~(-1)) of thiosulfate oxidation at the surface of,2,7-BFEFMCPE were determined.The electrocatalytic oxidation peak current of thiosulfate showed two linear dynamic ranges(0.0006-0.009 mmol/L and 0.009- 0.900 mmol/L) and a detection limit of 0.00015 mmol/L.This method was also examined as a new electrochemical sensor for the determination of thiosulfate in real sample.     

Recent Developments in EPOS: Core–Corona Effects in Air Showers?

Physics of Atomic Nuclei - EPOS-LHC is the public EPOS version, heavily used by experimental groups in high energy and cosmic ray physics. It is based on an S-matrix approach, being the ideal...     

Developing a Nano‐Biosensor for DNA Hybridization Using a New Electroactive Label

Development of electrochemical DNA hybridization biosensors based on carbon paste electrode (CPE) and gold nanoparticle modified carbon paste electrode (NGMCPE) as transducers and ethyl green (EG) as a new electroactive label is described. Electrochemical impedance spectroscopy and cyclic voltammetry techniques were applied for the investigation and comparison of bare CPE and NGMCPE surfaces. Our voltammetric and spectroscopic studies showed gold nanoparticles are enable to facilitate electron transfer between the accumulated label on DNA probe modified electrode and electrode surface and enhance the electrical signals and lead to an improved detection limit. The immobilization of a 15‐mer single strand oligonucleotide probe on the working electrodes and hybridization event between the probe and its complementary sequence as a target were investigated by differential pulse voltammetry (DPV) responses of the EG accumulated on the electrodes. The effects of some experimental variables on the performance of the biosensors were investigated and optimum conditions were suggested. The selectivity of the biosensors was studied using some non‐complementary oligonucleotides. Finally the detection limits were calculated as 1.35×10^?10 mol/L and 5.16×10^?11 mol/L on the CPE and NEGCPE, respectively. In addition, the biosensors exhibited a good selectivity, reproducibility and stability for the determination of DNA sequences.     

A new peptide nucleotide acid biosensor for electrochemical detection of single nucleotide polymorphism in duplex DNA via triplex structure formation

In this paper, we report a new PNA biosensor for electrochemical detection of point mutation or single nucleotide polymorphism (SNP) in p53 gene corresponding oligonucleotide based on PNA/ds-DNA triplex formation following hybridization of PNA probe with double-stranded DNA (ds-DNA) sample without denaturing the ds-DNA into single-stranded DNA (ss-DNA). As p53 gene is mutated in many human tumors, this research is useful for cancer therapy and genomic study. In this approach, methylene blue (MB) is used for electrochemical signal generation and the interaction between MB and oligonucleotides is studied by differential pulse voltammety (DPV). Probe-modified electrode is prepared by self-assembled monolayer (SAM) formation of thiolated PNA molecules on the surface of Au electrode. A significant increase in the reduction signal of MB following hybridization of the probe with the complementary double-stranded oligonucleotide (ds-oligonucleotide) confirms the function of the biosensor. The selectivity of the PNA sensor is investigated by non-complementary ds-oligonucleotides and the results support the ability of the sensor to detect single-base mismatch directly on ds-oligonucleotide. The influence of probe and ds-DNA concentrations on the effective discrimination against complementary sequence and point mutation is studied and the concentration of 10^?6 M is selected as appropriate concentration. Diagnostic performance of the biosensor is described and the detection limit is found to be 4.15 × 10^?12 M.     

Introduction of Ketamine as a G‐Quadruplex‐Binding Ligand Using Platinum Nanoparticle Modified Carbon Paste Electrode

We designed an electrochemical platform by modifying a carbon paste electrode (CPE) with platinum nanoparticles to study the interaction between ketamine and the G‐quadruplex structure of human telomeric DNA (G₄HTD). The drug ketamine (Kt) was used as the model ligand and its ability for stabilizing the G‐quadruplex structure was examined. The modified CPE (NPtCPE) was characterized by differential pulse voltammetry (DPV) and atomic force microscopy (AFM). The interaction of Kt with G₄HTD was studied by DPV and the DPV current decreased with increasing Kt concentration. The results from UV‐vis and circular dichroism (CD) spectroscopy showed a prominent intercalation mode between G₄HTD and Kt.     

Cordyceps militaris Fungus Extracts-Mediated Nanoemulsion for Improvement Antioxidant,Antimicrobial, and Anti-Inflammatory Activities

This study aimed to produce and optimize a Cordyceps militaris-based oil-in-water (O/W) nanoemulsion (NE) encapsulated in sea buckthorn oil (SBT) using an ultrasonication process. Herein, a nonionic surfactant (Tween 80) and chitosan cosurfactant were used as emulsifying agents. The Cordyceps nanoemulsion (COR-NE) was characterized using Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and field-emission transmission electron microscope (FE-TEM). The DLS analyses revealed that the NE droplets were 87.0 ± 2.1 nm in diameter, with a PDI value of 0.089 ± 0.023, and zeta potential of −26.20 ± 2. The small size, low PDI, and stable zeta potential highlighted the excellent stability of the NE. The NE was tested for stability under different temperature (4 °C, 25 °C, and 60 °C) and storage conditions for 3 months where 4 °C did not affect the stability. Finally, in vitro cytotoxicity and anti-inflammatory activity were assessed. The results suggested that the NE was not toxic to RAW 264.7 or HaCaT (human keratinocyte) cell lines at up to 100 µL/mL. Anti-inflammatory activity in liposaccharides (LPS)-induced RAW 264.7 cells was evident at 50 µg/mL and showed inhibition of NO production and downregulation of pro-inflammatory gene expression. Further, the NE exhibited good antioxidant (2.96 ± 0.10 mg/mL) activity and inhibited E. coli and S. aureus bacterial growth. Overall, the COR-NE had greater efficacy than the free extract and added significant value for future biomedical and cosmetics applications.