Pulsed laser interference patterning of transition-metal carbides for stable alkaline water electrolysis kinetics

We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition-metal carbides(TMCs;namely,Co_(3)C,Fe_(3)C,TiC,and MoC)by pulsed laser ablation of Co,Fe,Ti,and Mo metals in acetone.The interaction between carbon s-p-orbitals and metal d-orbitals causes a redistribution of valence structure through charge transfer,leading to the formation of surface defects as observed by X-ray photoelectron spectroscopy.These defects influence the evolved TMCs,making them effective for hydrogen and oxygen evolution reactions(HER and OER)in an alkaline medium.Co_(3)C with more oxygen affinity promoted CoO(OH)intermediates,and the electrochemical surface oxidation to Co_(3)O_(4)was captured via in situ/operando electrochemical Raman probes,increasing the number of active sites for OER activity.MoC with more d-vacancies exhibits strong hydrogen binding,promoting HER kinetics,whereas Fe_(3)C and TiC with more defect states to trap charge carriers may hinder both OER and HER activities.The results show that the assembled membrane-less electrolyzer with Co_(3)C∥Co_(3)C and MoC∥MoC electrodes requires~2.01 and 1.99 V,respectively,to deliver a 10 mA cm−2 with excellent electrochemical and structural stability.In addition,the ascertained pulsed laser synthesis mechanism and unit-cell packing relations will open up sustainable pathways for obtaining highly stable electrocatalysts for electrolyzers.

A case of atypical neurological symptoms and high cerebro-spinal fluid acetone level due to transdermal exposure to isopropanol

Dear editor, Isopropanol, also named 2-propanol or isopropyl alcohol(IPA), is a colorless, volatile liquid found in numerous household chemicals, such as cleaners and disinfectants, which typically contain a 70% solution of IPA in water. IPA is also extensively used in industry and laboratories as a solvent.

Breath-by-breath measurement of exhaled ammonia by acetonemodifier positive photoionization ion mobility spectrometry via online dilution and purging sampling

Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH_(3)with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH_(3)product ion peak of(C_(3)H_(6)O)_(4)NH_(4)^(+)(K_(0)=1.45 cm^(2)/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C_(3)H_(6)O)_(2)H^(+)(K_(0)=1.87 cm^(2)/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH_(3)qualitative identification.Moreover,the interference of high humidity and the memory effect of NH_(3)molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92μmol/L with a response time of 40 ms was achieved,and the exhaled NH_(3)profile could be synchronized with the concentration curve of exhaled CO_(2).Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH_(3)of healthy subjects,demonstrating its great potential for clinical disease diagnosis.

Construction of multi-walled carbon nanotubes/ZnSnO_(3)heterostructures for enhanced acetone sensing performance

Carbon nanotubes(CNTs)have attracted many researcher's attention in gas sensing field because of their excellent physical and chemical properties.Herein,multi-walled carbon nanotubes(MWCNTs)/ZnSnO_(3)heterostructures have been obtained by a simple hydrothermal method without additional annealing process.The structural and composition information are characterized by x-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and x-ray photoelectron spectroscopy(XPS).The acetone sensing properties of pure MWCNTs,ZnSnO_(3)and MWCNTs/ZnSnO_(3)heterostructures are systematically investigated,respectively.The results show that MWCNTs/ZnSnO_(3)heterostructures have better sensing properties compared with pure MWCNTs and ZnSnO_(3)sample.Specifically,MWCNTs/ZnSnO_(3)heterostructures exhibit not only high responses of 24.1 and rapid response/recovery speed of 1 s/9 s to 100 ppm acetone,but also relatively good repeatability and long-term stability.The enhanced sensing performance is analyzed in detail.In addition,this work provides the experimental and theory basis for synthesis of high-performance MWCNT-based chemical sensors.

非接触式人体气味标志化合物的定性研究

As a base research on intelligentized search technique in seismic ruins,we study on human odor by a portable GC-MS.Qualitative analysis experiment demonstrate that isoprene,acetone and 6-methyl-5-heptene-2-one are symbol of human odor.This research give important data to search survival base on artificial olfaction technique in seismic ruins.

几种N-烷基吲哚衍生物的合成

介绍了吲哚衍生物在药物合成中的重要用途,叙述了N-烷基吲哚衍生物的主要合成方法,采用了以吲哚及取代吲哚为原料,与卤代烃在KOH/acetone体系室温下几小时可得目标化合物,产品进行了纯化和结构鉴定.产品纯度达98%以上,反应总收率80%以上,产品为淡黄色液体或棕色固体.

Studies on Acaricidal Bioactivities of Artemisia annua L.Extracts Against Tetranychus cinnabarinus Bois.(Acari:Tetranychidae)

The aim of this study was to determine the best extraction technique, the most suitable solvent, the optimal plant parts, and the acaricidal activities of Artemisia annua L. The petroleum ether （30-60℃）, petroleum ether （60-90℃）, ethanol, acetone, and water parallel and sequenced extracts were obtained from the leaves, stems and roots of different period of A. annua L. in April, May, June, July and September respectively. And then the acaricidal bioactivities against Tetranychus cinnabarinus of all extracts were determined by the slide-capillary method in the laboratory. The results indicated that the acaricidal bioactivities elevated as the development of A. annua plant at the concentration of 5 mg mL-L The general tendency exhibited the sequence of July 〉 June 〉 May 〉 April, but September decreased comparing to July. However, the most effective extracts in five months were all acetone parallel extract of A. annua leaf, and the corrected mortalities treated after 48 h ranged from 74 to 100%. The median lethal concentrations （LC50） against T. cinnabarinus of acetone parallel extracts ofA. annua leaves in September, July, June, May and April were 0.5986, 0.4341, 0.8376, 0.9443 and 1.3817 mg mL^-1, respectively, treated after 48 h. The 13 groups were isolated from acetone extracts ofA. annua leaves in July by column chromatography, both the 1 lth and 12th groups exhibited strong bioactivities. The median lethal concentrations of the 1 lth and 12th groups against T. cinnabarinus were 0.3683 and 0.1586 mg mL^-1, respectively. The acetone parallel extract ofA. annua leaf in July was the most toxic to T. cinnabarinus and the corrected mortality was 100% after 48 h. The acetone parallel extract of the 1 lth and 12th groupswere the most active components, acted as the emphases in further study.

Sodium modification of zirconia catalysts for ethanol coupling to 1-butanol

The influences of adding sodium to zirconia on the acid-base properties of the surface and on the catalytic conversion of ethanol and acetone were investigated. The rates of ethanol dehydration, dehydrogenation and coupling were evaluated in a fixed-bed flow reactor operating at temperatures from 613 to 673 K. The rate of acetone condensation was evaluated in the same reactor operating at 473-573 K. Addition of 1.0 wt% Na to ZrO2 decreased the rate of ethanol dehydration by more than an order of magnitude, which was consistent with a neutralization of acid sites evaluated by ammonia adsorption microcalorimetry. Addition of 1.0 wt% Na to ZrO2 also increased the base site density quantified by carbon dioxide adsorption microcalorimetry and the rate of acetone condensation. Although the rate of ethanol coupling was not increased by the addition of Na, the overall selectivity of ethanol to butanol was improved over the 1.0 wt% Na/ZrO2 sample because of the significant inhibition of ethanol dehydration.

Acetone sensors for non-invasive diagnosis of diabetes based on metal-oxide-semiconductor materials

In recent years, clinical studies have found that acetone concentration in exhaled breath can be taken as a characteristic marker of diabetes. Metal-oxide-semiconductor (MOS) materials are widely used in acetone gas sensors due to their low cost, high sensitivity, fast response/recovery time, and easy integration. This paper reviews recent progress in acetone sensors based on MOS materials for diabetes diagnosis. The methods of improving the performance of acetone sensor have been explored for comparison, especially in high humidity conditions. We summarize the current excellent methods of preparations of sensors based on MOSs and hope to provide some help for the progress of acetone sensors in the diagnosis of diabetes.

A Selective Luminescent Acetone Sensing Coordination Polymer Constructed from Zinc(Ⅱ) Ions and Imidazolyl-bearing Ligands

Solvothermal reaction of imidazolyl-based synthon with deprotonated adipic acid produced a new coordination complex {[Zn（BIDPE）(hdc)]·2 H;O}n（1）. The structure was characterized by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group C2/m, at 293 K: a = 12.005（2）, b = 17.956（3）, c = 12.039（2） ?, β = 113.089（3）°, V = 2387.3（7） ?;, Z = 4, Dc = 1.524 g·cm-3, μ（Mo Ka） = 1.082 mm–1 and F（000） = 1136. 5942 reflections were measured and 2180 independent reflections（Rint = 0.0679） were used in further refinement. Complex 1 reveals 1D double-stranded chains containing [Zn;（BIDPE）;] and [Zn;（hdc）;] metallocyclic rings. The adjacent chains are linked by H-bonding and π···π interactions to form a 3D network. Thermal stability and luminescence property were studied. Interestingly, the luminescent emission of 1 can be quenched by the addition of trace amount of acetone, demonstrating its potential application for sensitive detecting acetone.

Pharmacognostical,phytochemical and pharmacological evaluation for the antipyretic effect of the seeds of Saraca asoca Roxb.

Objective:To conduct a systemic evaluation of the medicinal value of seeds which include macroscopic and microscopic characterization,physiochomical evaluation,preliminary phylochemical screening and experimental antipyretic activity.Methods:Saraca asoca seed was studied for pharmacognostical,phytochemical and other recommended methods for standardizations.Also,the acetone extract of the seeds was evaluated for acute toxicity study and antipyretic activity using Brewer's yeast induced pyrexia in Wislar rats at oral doses of 300 mg/kg and 500 mg/kg.Results:After phytochemical screening,the acetone extract showed the presence of saponin,tannins and flavonoids which inhibit pyrexia.The therapeutic efficacy achieved at both the dose levels of the research drug and standard drug aspirin(100 mg/kg)showed significant(P<0.01)antipyretic activity when compared to the control group.The highly significant antipyretic effect exhibited at the dose of 500 mg/kg was also found to be sustainable in nature.Conclusions:The antipyretic effect of the acetone extract showed significant results in rats at the dose of 500 mg/kg after following the standard pharmacognostical and phylochemieal met hods.

Effect of Pd doping on the acetone-sensing properties of NdFeO_3

The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO3 were investigated from room temperature to 400°C. The perovskite-type NdFeO3 was synthesized by a sol-gel method, and the dopants Pd with the content from 1wt% to 5wt% were implanted into NdFeO3 nanoparticles by thermal diffusion. X-ray diffraction （XRD） and scanning electron microscopy （SEM） techniques show that NdFeO3 is an orthorhombic structure with the average particle size of about 40 nm. A giant acetone-sensing response of 675.7 is observed when the Pd content in NdFeO3 powders is about 3wt%. The response and recovery time of the sensor to the 5×10–4 acetone gas are 16 and 1 s, respectively. At the same time, it performs a good selectivity to acetone gas and may be a new promising material candidate for the acetone-sensor development.

Extraction of Flavonoids from Bitter Melon

Bitter melon, Momordica charantia L, is a popular traditional medicinal fruit in tropical and subtropical countries. It has been linked with therapeutic effects, some of which are likely due to its flavonoids. To determine its total flavonoid content (TFC) and to prepare extracts for use as nutritional supplements or ingredients for nutraceutical functional foods, various solvents have been used, including water, which is the preferred solvent because it is inexpensive, safe and environmentally friendly. The study aimed to extract bitter melon, using five solvents (ethanol, methanol, n-butanol, acetone and water) before and after the optimal conditions for water were determined in terms of extraction temperature, time, ratio of water to bitter melon (mL/g) and number of times the same material was extracted. The TFC of six varieties of bitter melon was also determined. Acetone was the best of the five solvents for extracting flavonoids from the Moonlight variety (23.2 mg Rutin Equivalents (RE)/g). Even after increasing the extraction by 88% (1.24 vs 0.66 mg RE/g) using optimised conditions for the aqueous extraction (two extractions at 40℃ for 15 min at a ratio of 100:1 mL/g of bitter melon powder), the flavonoids extracted from the Moonlight variety using water was very little (5.4%) compared to acetone. Furthermore, using acetone, it was shown that the Moonlight variety (23.2 mg RE/g) bought at a local market had higher levels of flavonoids than the greenhouse-grown Jade (15.3 mg RE/g), Niddhi (16.9 mg RE/g), Indra (15.0 mg RE/ g), Hanuman (3.9 mg RE/g) and White (6.9 mg RE/g) varieties. Therefore, acetone was the best solvent for extracting flavonoids from bitter melon and the aqueous extraction could only be improved to extract 5.4% of the flavonoids extracted with acetone from the Moonlight variety, which had the highest TFC of the six varieties of bitter melon.

Measurement Uncertainty Assessment of Magnesium Trisilicate Column for Determination of Sudan Colorants in Food by HPLC Using C8 Column

This study aimed to conduct measurement uncertainty assessment of a new method for determination of Sudan colorants（Sudan Ⅰ, Ⅱ, Ⅲ and Ⅳ） in food by high performance liquid chromatography（HPLC）. Samples were extracted with organic solvents（hexane, 20% acetone） and first purified by magnesium trisilicate（2Mg O·3Si O2）. The Sudan colorants（Sudan Ⅰ–Ⅳ） were also initially separated on C8 by gradient elution using acetonitrile and 0.1%（v/v） formic acid aqueous solution as the mobile phases and detected with diode-array detector（DAD）. The uncertainty of mathematical model of Sudan Ⅰ, Ⅱ, Ⅲ, Ⅳ is based on EURACHEM guidelines. The sources and components of uncertainty were calculated. The experiment gave a good linear relationship over the concentration from 0.4 to 4.0 μg/m L and spiked recoveries were from 74.0% to 97.5%. The limits of determination（LOD） were 48, 61, 36, 58 μg/kg for the four analytes, respectively. The total uncertainty of Sudan colorants（Sudan Ⅰ, Ⅱ, Ⅲ and Ⅳ） was 810±30.8, 790±28.4, 750±27.0, 730±50.0 μg/kg, respectively. The recovery uncertainty was the most significant factor contributing to the total uncertainty. The developed method is simple, rapid, and highly sensitive. It can be used for the determination of trace Sudan dyes in food samples. The sources of uncertainty have been identified and uncertainty components have been simplified and considered.

NMR IMAGING OF ACETONE DIFFUSION PROCESS IN POLYCARBONATE

Acetone diffusion in polycarbonate was investigated by spin-echo ~1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is 13.8nm sec^(-1)(0.05mm/h).

Preparation of Polyfunctionally Substituted Pyridine-2(1<i>H</i>)-Thione Derivatives as Precursors to Bicycles and Polycycles

Reaction of acetylacetone with 1 mole of dimethylformamide dimethyl acetal (DMFDMA) affords enamine 2a which reacts with cyanothioacetamide to give pyridinethione 3a. Pyridinethione 3a reacts with methyl iodide, halogenated compounds, aromatic aldehyde and malononitrile/elemental sulfur to yiled compounds 7-10 respectively. Reactions of thioether 7 in ethanolic K2CO3, 1 mole DMFDMA and 4-(dimethylamino)benzaldehyde give compounds 11, 13, 14 respectively. Enaminone 12 can be prepared by reaction of compound 11 with DMFDMA. We have demonstrated some reactions in order to show the potential usefulness of the prepared compounds for the preparation of new bipyridyl compounds 15, 16, 18, bicyclic compounds 17 and uncommon tricyclic compounds 20, 21, 22 and 23 respectively using DMFDMA.

Effects of the Discharge Parameters on the Efficiency and Stability of Ambient Metastable-Induced Desorption Ionization

Ionization efficiency is an important factor for ion sources in mass spectrometry and ion mobility spectrometry.Using helium as the discharge gas,acetone as the sample,and high-field asymmetric ion mobility spectrometry（FAIMS） as the ion detection method,this work investigates in detail the effects of discharge parameters on the efficiency of ambient metastableinduced desorption ionization（AMDI） at atmospheric pressure.The results indicate that the discharge power and gas flow rate are both significantly correlated with the ionization efficiency.Specifically,an increase in the applied discharge power leads to a rapid increase in the ionization efficiency,which gradually reaches equilibrium due to ion saturation.Moreover,when the discharge voltage is fixed at 2.1 kV,a maximum efficiency can be achieved at the flow rate of 9.0 m/s.This study provides a foundation for the design and application of AMDI for on-line detection with mass spectrometry and ion mobility spectrometry.

Hepatoprotective effect of acetone semicarbazone on Ehrlich ascites carcinoma induced carcinogenesis in experimental mice

Objective:To determine the hepatoprotective effect of acetone semicarbazone(ASC)in vivo in normal and Ehrlich ascites carcinoma(EAC)bearing male Swiss albino mice.Methods:Druginduced changes in biochemical and behavioral parameters at dose of 2.0 mg/kg body weight for14 d and nullifying the toxicity induced by EAC cells were studied.The histopathology studies of the protective effects of ASC on vital organs were also assessed.Results:The administration of ASC made insignificant changes in body weight and behavioral(salivation,diarrhea,muscular numbness)changes during treatment period due to minor toxicity were minimized after the treatment in normal mice.The biochemical parameters,including serum glutamate pyruvate transaminase,glutamate oxaloactate transaminase,alkaline phosphatase,serum glucose,cholesterol,urea,triglyceride and billirubin changed modestly in normal mice receiving ASC.Though the treatment continued,these values gradually decreased to normal level after the treatment.In EAC bearing mice,the toxic effects due to EAC cells in all cases were nullified by treatment with the ASC.Significant abnormalities were not detected in histology of the various organs of the normal mice treated with ASC.Conclusions:ASC can,therefore,be considered safe in formulating novel anticancer drug,as it exhibits strong protective effect against EAC cell bearing mice.

Geometrical,energetic and electronic properties of Au_n-(C_3H_6O)_m complexes(n = 3,5,m≤n):A density functional theory study

The interactions of acetone molecules with clusters of Au3 and Au5 are investigated by using a density functional theory （DFT） within a generalized gradient approximation （GGA）. The geometries, adsorption energies and deformation electron density distributions are used to analyse these interactions. The present calculations show that more than one acetone molecules can be adsorbed onto small gold clusters, and this adsorption is different from that of single molecule absorption. The coordination number of the adsorption site on the gold cluster is the dominant factor responsible for the strength of the interactions. The effects of the Au O bond lengths in the complexes on adsorption energies between Au clusters and acetone molecules are also examined.