Synthesis of ethylidene diacetate from dimethyl ether,CO and H_2

Ethylidene diacetate was prepared by reacting dimethyl ether,acetic acid and syngas in the presence of a catalytic system comprising RhI3,PPh3 and CH3I.The effects of reaction temperature,pressure,time and the CO/H2 molar ratio on the conversion of dimethyl ether and the product selectivity were investigated under the same catalyst formulation.Results showed that a maximum conversion of dimethyl ether was obtained when a mixture consisting of 0.3 mol dimethyl ether and 120 ml acetic acid was reacted at 180 ℃ and 3.0 MPa for 10 h at a stirring speed of 600 rpm under a syngas flow with a CO/H2 molar ratio of 2.5,which was catalyzed by a catalyst mixture comprising 0.3 g RhI3,6 g PPh3 and 1.3 g CH3I.The selectivity of ethylidene diacetate increased with temperature,decreased with the CO/H2 molar ratio and exhibited a maximum with pressure.

Biomimetic Epxidation of Alkenes by Phenyliodonium Diacetate [PhI(OAc)_2] in the Presence of Mn(Ⅲ) Complex of meso-Tetrakis(4-methoxyphenylporphyrin) Acetate Mn[(T4-OCH_3P)P]OAc

We have reported that phenyliodonium diacetate[PhI（OAc）2] can serve as an eco-friendly mild oxidant for the epoxidation of alkenes in the presence of Mn（III） complex of meso-tetrakis（4-methoxyphenylporphyrin） acetate Mn[（T4-OCH3P）P]OAc and imidazole in CH2Cl2.The amounts of the products（%） and selectivities are very dependent upon the electronic and steric properties of the starting alkenes.To evaluate the validity of this catalytic system for C ＂H activation,cyclohexane and ethylbenzene were oxidized under the epoxidation conditions.

Laser Light Scattering Study on Aggregation of Cellulose Diacetate in Acetone

We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.

Cobalt Sulfate as a Recyclable Catalyst for Chemoselective Synthesis of Diacetates from Aldehydes

A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yield,at room temperature,without solvent.The catalyst could be recycled six times without a distinct loss of activity.

Synthesis and Crystal Structure Analysis of 4-Dibenzaldehydeamino-4H-1,2,4-triazole Diacetate

The new title compound 4-dibenzaldehydeamino-4H-1,2,4-triazole diacetate （C16H18N8O4,Mr = 386.38） has been prepared and its crystal structure was determined by single- crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 8.1371（17）,b = 7.1237（12）,c = 16.325 （2）A,β = 100.366（2）°,V = 930.9（3） A^3,Z = 2,Dc = 1.378,F（000） = 404,μ = 0.104 mm^-1,MoKa radiation （λ = 0.71073 ）,R = 0.0307 and wR = 0.1196 for 4632 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the molecule is not flat and the crystal structure is stabilized mainly by van der Waals interactions.

Highly Efficient, One Pot Synthesis and Oxidation of Hantsch 1,4-Dihydropyridines Mediated by Iodobenzene Diacetate (III) Using Conventional Heating, Ultrasonic and Microwave Irradiation

A mild, general, convenient, and efficient one-pot synthesis of 4-arylpyridines (4) is described using conventional heating, ultrasound and microwave irradiation. Aryl aldehydes (2) were efficiently condensed with ethylacetoacetate (1) and ammonium acetate in acetonitrile to give dihydropyridine intermediates (4). The latter underwent a smooth Iodobenzene Diacetate (III) mediated aromatization reaction in the same pot to afford 4-arylpyridines (4) in good to excellent yields.

Tracking in vivo migration and distribution of antigen-specific cytotoxic T lymphocytes by 5,6-carboxyfluorescein diacetate succinimidyl ester staining during cancer immunotherapy

Background Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte （CTL） numbers,immunophenotype,tumor-specificity,and in vivo residence time,migration,and distribution.Therefore,tracing in vivo persistence,migration,and distribution of CTLs is important for cancer immunotherapy.Methods Optimal staining concentration for CTL proliferation was determined by cell counting kit-8 （CCK-8） assay and killing efficiencies of CTLs or carboxyfluorescein diacetate succinimidyl ester （CFSE）-labeled melanoma antigen-specific cytotoxic T lymphocytes （CFSE-CTLs） for malignant melanoma cells in vitro were compared.Additionally,CFSE-CTLs were intravenously transfused to mice receiving B16 melanoma,and their residence time,migration,and distribution in vivo were observed by measuring fluorescence intensities of CFSE-CTLs per gram of tissue （％FI/g） in various tissues and analyzing tumor/non-tumor （T/NT） values.Anti-tumor effects of transferred CTLs and correlation between ％FI/g and D-value of tumor size were analyzed.Results Five-micromolar CFSE was optimal for labeling CTLs with minimal cytotoxicity.No significant difference occurred between CTLs and CFSE-CTLs for tumor cell killing （P=0.849） or interleukin-2 （P=0.318） and interferon-y （P=0.201）levels.Distribution of CTLs in vivo varied with time.A negative correlation between ％FI/g in tumors and D-value of tumor sizes by Spearman correlation analysis was observed.CTLs were recruited to and killed tumors from 6 hours to 3 days after cell infusion.CTLs were observed up to three weeks later in the tumor,liver,kidneys,and spleen; this was related to the abundant blood supply or the nature of immune organs.Conclusions CCK-8 assay is a novel method to select optimal CFSE staining concentrations.Fluorescence intensity of transferred CTLs reflects their killing efficiency of tumors.CFSE fluorescent markers can trace in vivo CTL persistence,migration,and distribution because of its stability,long half-life,and low toxicity.

Novel antibacterial cellulose diacetate-based composite 3D scaffold as potential wound dressing

In this work,novel antibacterial cellulose diacetate/poly(ethylenimine)/hyaluronic acid(CDA/PEI/HA)composite three-dimension(3D)scaffolds were prepared through electrospinning and post-processing.Firstly,CDA/PEI 2D composite nanofiber membranes were prepared by electrospinning,and then the CDA/PEI/HA 3D composite scaffolds were fabricated by post-processing and freeze-drying of CDA/PEI membranes.In particular,HA was added to improve the biocompatibility of composite scaffolds.Compared with CDA/PEI scaffolds,CDA/PEI/HA composite scaffolds showed higher water absorbing rate,higher water retention rate and higher mechanical strength.Moreover,CDA/PEI/HA composite scaffolds with abundant positive charge were benefit for improving antibacterial activity.CDA/PEI/HA scaffolds with biology function of HA were benefit for improving hemocompatibility and cell proliferation of CDA/PEI scaffolds.In summary,antibacterial CDA/PEI/HA scaffolds could protect wound from bacterial infection,improve cellular behavior and accelerate wound healing.Thus,CDA/PEI/HA scaffolds could be potential application for wound dressing.

Preparation of green cellulose diacetate-based antibacterial wound dressings for wound healing

Managing wounds is a growing universal problem and developing effective wound dressings to staunch bleeding and protect wounds from bacterial infections is an increasingly serious challenge.In this work,a remolding electrospinning nanofiber three-dimensional structure wound dressing(CCP)was prepared with superhydrophilicity,high water absorption and absorbing capacity,excellent hemostatic capacity and antibacterial ability,and biocompatibility to promote wound healing.Polyhexamethylene guanidine hydrochloride(PHMG)was grafted to cellulose diacetate(CDA)wound dressing surface through an amide reaction.A water contact angle analysis demonstrated that CCP wound dressing could be beneficial to promote wound exudate management effectively with rapid absorption of water within 0.2 s.In vitro hemo-and cytocompatibility assay showed that a CCP wound dressing had no significant hemotoxicity or cytoxicity.Specifically,CCP wound dressings could be beneficial to accelerate wound hemostasis and further reduce mortality caused by uncontrolled bleeding.Furthermore,CCP wound dressings have an excellent antibacterial ability,which could be beneficial to inhibit wound inflammatory over-reaction and promote normal wound healing.Combined together,the prepared wound dressing in this research effort is expected to have high-potential in clinical applications.

Applicability of differential fluorescein diacetate and propidium iodide fluorescence staining for monitoring algal growth and viability

Microalgae can be cultivated for producing high-valued products through the production of enzymes to offset the cost of CO_(2) sequestration,providing financial incentives.The viability of algae in the photobioreactor needs to be monitored to ensure biologically active live cells.In this study,we explored a simple fluorometry method for differentiation of live and dead algal cells in photobioreactors by fluorescein diacetate(FDA)and propidium iodide(PI)fluorescence staining.FDA stains fluorescent green to the living cells while PI stains the dead cells,allowing the discrimination of live and dead cells.The method was evaluated using two green algae and two strains of cyanobacteria grown in shake flasks and a continuously stirred photobioreactor.The method was found applicable for Chlorella pyrenoidosa and Synechococcus 7002 but was not applicable for the cultures of Scenedesmus dimorphus and Synechococcus elongatus 7942.We conclude that FDA is a good stain for monitoring live algal cells in photobioreactors but its applicability to individual species of algae must be evaluated.

Synthesis of 3,5-diarylisoxazoles under solvent-free conditions using iodobenzene diacetate

A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, ^1H NMR, ^13C NMR and HRMS.

豚鼠耳蜗外毛细胞的一氧化氮定量分析

目的:为了观察一氧化氮底物左旋精氨酸(L-arginie)和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME)对豚鼠耳蜗外毛细胞一氧化氮的影响。方法:应用新的荧光染料4,5二氨基乙酰乙酸荧光素(4,5-diaminofluorescein diacetate,DAF-2DA)测定豚鼠耳蜗外毛细胞内一氧化氮的含量。结果:发现加左旋精氨酸后外毛细胞的荧光灰度值比正常外毛细胞的灰度值升高。而加左旋硝基精氨酸甲酯后,外毛细胞的荧光灰度值比正常外毛细胞的灰度值降低。结论:进一步证明豚鼠耳蜗外毛细胞内存在一氧化氮。

Evaluation of Soil Quality Indicators in Sugarcane Management in Sandy Loam Soil

An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (Saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (OS), green sugarcane (GS), burned sugarcane (BS) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWSA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > OS > GS > BS, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWSA decreased in the order NF > OS = GS > BS. The variables MWD and PWSA are quite sensitive for discriminating between site management histories regardless the sampling season.

A novel ionic liquid based on small size cation

An ionic liquid material containing small size cation was synthesized and its composition and structure was determined by FT- IR, ^1H NMR, ^13C NMR and element analysis. However, its physical properties such as melting point, viscosity, conductivity, etc. were measured and the results show that the novel ionic liquid is composed of small cation with highly symmetry and larger anion which is very rare among the reported ionic liquid family.

Synergistic Effect of the Methanolic Extract of Lemongrass and Some Antibiotics to Treat Urinary Tract Bacteria

Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana cama-ra), and wild olive leaves (Olea europaea) were collected, identified, extracted with either hot water or organic solvents (methanol, diethyl ether, ethyl acetate and n-butanol) to investigate their antibacterial activities against E. coli. The methanol ex-tracts of lemongrass, lantana and olive showed the highest activities against Esherichia coil while aqueous extract exhibited the lowest activities. Thus, the antibacterial activities of the methanolic extract of the three tested plants were determined using agar well diffusion method against some bacterial pathogens, isolated from urine samples. The highest antibacterial activity was recorded for themethanolic extract of lemongrass against all tested bacteria, E. coli, K. pneumoniae, P. aeuroginosa, P. mirabilis, E. faecalis and S. aureus. The tested bacteria differed with regard to their susceptibility to plant extracts. Lemongrass was the most active extract followed by lantana and wild olive extracts. Minimal inhibitory concentrations (MICs) of the methanolic extract of Lemongrass and some used antibiotics, Erythromycin, Tetracycline, Amoxicillin, Ciprofloxacin and Chloramphenicol were determined usingfluorescein diacetate method. Synergistic effect of the methanolic extract of lemongrass with the previous antibiotics against the tested clinical bacterial isolates was determined and the Fractional inhibitory concentrations (FIC) of different combination of the extract and the antibiotics were determined. FIC index (FICI) was calculated and it was ranged from 0.08 - 0.98. The interaction between the tested plant extract and the tested antibiotics was either synergistic or additive effects and no antagonistic effect was recorded. In conclusion, methanolic extract of lemongrass singly or in combination with some antibiotics can be used to treat pathogenic bacteria that cause urinary tract infections.

SYNTHESES AND ACTIVE BEHAVIOR OF NOVEL UV PHOTOINITIATORS

A series of novel hybrid photoinitiators(YPhCOPhXPhI^+PhPF_6^-,Y = 4-NO_2,4-MeO or 3-Cl,X = O,OCH_2,or nothing),which contain multiple aromatic rings(PhCOPhXPh),were prepared by reaction of easily available aryl ketones (YPhCOPhXPh) with iodosobenzene diacetate[PhI^+OCOCH_3(CH_3CO_2)^-].The inset of an aromatic ring into p-benzoyldiphenyliodonium hexafluorophophate(PhCOPhI^+PhPF_6^-)(BDPIH,He-type photoinitiator) between diphenyliodonium and benzoyl is propitious both to the preparation and the photoinitiat...

Oxidative effects of glyphosate on the lipophobic intracellular environment in the microalgae Chlorella vulgaris

The studied hypothesis is that the herbicide glyphosate(GLY)can affect the oxidative balance in the hydrophobic intracellular medium in non-target Chlorella vulgaris cells.Analytical GLY and RoundUp(RUP)supplementation,affected the growth profile.A significant 42%decrease in the cellular biomass in stationary(St)phase was observed in cultures supplemented with either 5μM of GLY or RUP,as compared to control cultures.The treatment with 0.3μM of GLY generated non-significant effects on the oxidation rate of 2’,7’dichlorofluorescein diacetate(DCFH-DA),neither in exponential(Exp)nor in St phase of development,as compared to control cultures.However,the treatment with either 5μM GLY or 0.3 and 5μM RUP lead to a significant decrease in the DCFH-DA oxidation rate,as compared to control cultures.The lipid radical(LR●)generation rate,detected by Paramagnetic Resonance Spectroscopy(EPR),was significantly increased in the presence of RUP,in Lag and Exp phase of growth.The non-enzymatic antioxidants,α-Tocopherol(α-T)andβ-Carotene(β-C),are aimed to protect membranes against the damage produced by the radical reactions.The content ofβ-C was not significantly affected,as compared to control cultures,by any of the treatments,in both growth phases of cellular development.The content ofα-T was significantly decreased by the supplementation with either 0.3 or 5μM of RUP or 5μM GLY.The LR●/α-T ratio,used as indicator of the oxidative balance in the hydrophobic cellular media,was significantly different between samples obtained from control and RUP-exposed microalgae in both,Exp and St phase of development,with either 0.3 or 5μM RUP.The data presented here showed evidence that suggested that oxidative balance in the hydrophobic environment was affected by either GLY or RUP.

Comparison of three fluorescence labeling and tracking methods of endothelial progenitor cells in laser-injured retina

AIM： To compare three kinds of fluorescent probes for in vitro labeling and in vivo tracking of endothelial progenitor cells（EPCs） in a mouse model of laser-induced retinal injury.METHODS： EPCs were isolated from human umbilical cord blood mononuclear cells and labeled with three different fluorescent probes： 5-（and-6）-carboxyfluorescein diacetate succinimidyl ester（CFSE）, 1,1′-dilinoleyl-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate linked acetylated low-density lipoprotein（Di I-Ac LDL）, and green fluorescent protein（GFP）. The fluorescent intensity of EPCs was examined by confocal microscopy. Survival rate of labeled EPCs was calculated with trypan blue staining, and their adhesive capability was assessed. A mouse model of retinal injury was induced by laser, and EPCs were injected into the vitreous cavity. Frozen section and fluorescein angiography on flat-mounted retinal samples was employed to track the labeled EPCs in vivo.RESULTS： EPCs labeled with CFSE and Di I-Ac LDL exhibited an intense green and red fluorescence at the beginning; the fluorescence intensity decreased gradually to 20.23% and 49.99% respectively, after 28 d. On the contrary, the florescent intensity of GFP-labeled EPCs increased in a time-dependent manner. All labeled EPCs showed normal morphology and no significant change in survival and adhesive capability. In the mouse model, transplantation of EPCs showed a protective effect against retinal injury. EPCs labeled with CFSE and Di I-Ac LDL were successfully tracked in mice during the development of retinal injury and repair; however, GFP-labeled EPCs were not detected in the laser-injured mouse retina.CONCLUSION： The three fluorescent markers used in this study have their own set of advantages and disadvantages. CFSE and Di I-Ac LDL are suitable for short-term EPClabeling, while GFP should be used for long-term labeling. The choice of fluorescent markers should be guided by the purpose of the study.

A new approach to the synthesis of diacetals(diketals) pentaerythritol catalyzed by SO_3H-functionalized ionic liquids

In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals) pentaerythritol using SOH-functionalized ionic liquids(ILs) as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.