Investigation of Cold Atmospheric Plasma-Activated Water for the Dental Unit Waterline System Contamination and Safety Evaluation in Vitro

The disinfection of the inner surface of a medical device has long been a challenge for the central sterile supply departments. Dental unit waterline system (DUWLs) foster the attachment of microorganisms and development of biofilm, which lead to continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff. The present study investigated the disinfection effects of cold atmospheric plasma-activated water (CAPAW) on DUWLs using a model of 5-day-old Enterococcus faecalis biofilm. The results showed that the colony-forming unit was reduced from 10⁷ to 0 after 5 min of treatment. The physicochemical properties of CAPAW were evaluated, including the pH value, oxidation reduction potential, and NO radical. The results showed that the inactivation mechanisms were mainly triggered by the reactive oxygen/nitrogen species. Additionally, CAPAW had a metal corrosion rate same as that of deionized water. We conclude that CAPAW can be applied as an appropriate alternative disinfectant against biofilm contamination of DUWLs.     

A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation

With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.     

Expression and Enzyme Activity Detection of a Sepiapterin Reductase Gene from <Emphasis Type="Italic">Musca domestica</Emphasis> Larva

Tetrahydrobiopterin (BH4) is an essential cofactor for aromatic acid hydroxylases and nitric oxide synthase. Sepiapterin reductase (SPR) catalyzes the final steps of BH4 biosynthesis. Studies on SPR from several insects and other organisms have been reported. However, thus far, enzyme activity of SPR in Musca domestica is kept unknown. In this study, 186 differentially expressed genes including SPR gene from Musca domestica (MDSPR) were screened in subtractive cDNA library. The MDSPR gene was cloned, and the recombinant MDSPI16 protein was expressed as a 51-kDa protein in soluble form. The MDSPR exhibited strong activity to the substrate sepiapterin (SP). The values of V_max and K_m of the MDSPR for SP were 6.83 μM/min and 23.48 μM, and the optimum temperature and pH of MDSPR were 50 °C and 4.0, respectively. This study provides new hypotheses and methods for the production of BH4 using insect-derived SPR.     

Facile synthesis of novel [1,3]oxazino[2,3-c][1,2,4] thiadiazin-12-one derivatives

Several novel fused heterocyclic systems which have rings containing N/O or N/S have been synthesized through a facile one-pot method by the treatment of substituted 2-(benzo[d]thiazol-2-yl)phenol and cyanogen bromide in THF and NEt₃. This one-pot method contains tough ring-opening of thiazole, special intermolecular rearrangement and ring-closing reactions. The newly synthesized compounds were characterized by HR-MS, ¹H-NMR, ¹³C-NMR spectral data and DFT calculation analysis. 2a was also determined by X-ray crystallographic analysis.     

Heterogeneity in optimized solid-state synthesis of metavanadate AVO3 (A = Rb,Cs)

Research on Chemical Intermediates - Methanol was used to optimize the solid-state synthesizing method of alkali metavanadates AVO3 (A&nbsp;=&nbsp;Rb, Cs) for the first time and the...     

Ag@AgCl embedded on cellulose film: a stable,highly efficient and easily recyclable photocatalyst

In this work, cellulose–Ag@AgCl composite films have been fabricated directly through a one-step coagulation of a cellulose/1-butyl-3-methylimidazolium chloride (BmimCl) solution with AgNO₃ and PVP. The AgCl was formed upon the addition of AgNO₃ to a cellulose/BmimCl solution, and underwent further reaction with excess Cl^?, leading to the complete dissolution of AgCl. The AgCl crystals were regenerated on the cellulose matrix during the coagulation process. The AgCl was partial decomposed to Ag⁰ and formed Ag@AgCl under visible light irradiation. The morphology of Ag@AgCl in the cellulose matrix was controlled by varying the concentration of PVP. The addition of PVP enabled the formation of stable cellulose films embedded with Ag@AgCl. The composite film demonstrated efficient photodegradation of methyl orange, which was retained upon recycling. This work thus provides a simple pathway for the preparation of Ag@AgCl embedded on a polymer support via one-step coagulation.     

Novel simple fluorescent sensor for nickel ions

A novel pyrazoline with benzimidazole substituent was conveniently synthesized, starting from a chalcone and 2-hydrazinylpyridine. The addition of Ni²⁺ to ethanol solution of the synthesized pyrazoline resulted in a rapid color change from blue to green which allows the selective detection of Ni²⁺ ion over a great number of other metal ions. The association constant for the 1:1 complex was determined to be 2.72 × 10⁷ M^?1.     

Preparations and photophysical properties of thermally activated delayed fluorescence materials based on N-phenyl-phenothiazine-S,S-dioxide

Four compounds (TM-1～4) based on N-(4-trifluoromethylphenyl)phenothiazine-S,S-dioxide and N-[3,5-bis(trifluoromethyl)phenyl]phenothiazine-S,S-dioxide are synthesized by Buchwald-Hartwig cross coupling reaction. The effect of different substituents in acceptors on the electronic, photophysical and electrochemical properties are studied by UV–Vis, fluorescence spectroscopy, cyclic voltammetry curves and theoretical calculations. The energy gaps (ΔE_ST) between singlet excited states (S₁) and triplet excited states (T₁) of these compounds decrease by addition of one para-substituted CF₃ or two meta-substituted CF₃ on N-phenyl in order to enhance the electron-withdrawing capability of the acceptors. Small ΔE_ST of these compounds range from 0.09 eV to 0.18 eV. TM-2～4 exhibit thermally activated delayed fluorescence (TADF) characteristics with short delayed fluorescence lifetimes (τ_d) within 0.69-1.16 μs. TM-3 emits blue light with an emission wavelength of 475 nm.     

One step synthesis of indirubins by reductive coupling of isatins with KBH4

One step synthesis of the natural product indirubin by reductive coupling of isatin with KBH₄ is described and a possible mechanism for the reaction is proposed. Eleven indirubin derivatives were obtained easily from the corresponding substituted isatin.     

Synthesis of polysubstituted 5-hydroxyhydantoins via ring-opening of isatins

A simple and efficient tandem reaction approach was developed for the synthesis of 5-hydroxyhydantoins from one-pot reaction of isatins, phthalic anhydride or succinic anhydride, and 1,3-dimethylurea (1,3-diethylurea). The products were gained through the ring-opening of isatins process. The advantages of this report are simple operation, mild reaction conditions, good yields and easily available raw materials. It was very important for us to obtain the intermediate product and that provided a solid basis for the correct interpretation of the reaction mechanism.