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.

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.

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.

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.

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).

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.

Theoretical Studies on the Mechanism of Photocycloaddition Reaction Between 6 Azauracil and Acetone

The mechanism of photocycloaddition reaction between 6-azauracll and acetone was studied by using semiemptrical SCFMO AMI method. It was found that this reaction is not a concerted one. The calculated results are as follows:(1) A T1 state exciplex is on the T1 state energy surface; (2) T exciplex as a reactant will proceed along the energy surface of T1 state to form a diradical intermediate. The energy barrier of this reaction step is 63. 6 kJ/mol; (3) The T1 state diradical intermediate happens to be close in energy to the ground state intermediate with a similar geometry. Such a situation turns out to be very favorable for an intersystem crossing (jump from the T, state to the ground state) ; (4) The final product will be formed from the ground S0 state intermediate via an energy barrier 88. 2 kJ/mol.

Excellent acetone sensing properties of porous ZnO

Porous Zn O was obtained by hydrothermal method. The results of scanning electron microscope revealed the porous structure in the as-prepared materials. The acetone sensing test results of porous Zn O show that porous Zn O possesses excellent acetone gas sensing properties. The response is 35.5 at the optimum operating temperature of 320？C to 100 ppm acetone. The response and recovery times to 50 ppm acetone are 2 s and 8 s, respectively. The lowest detecting limit to acetone is 0.25 ppm, and the response value is 3.8. Moreover, the sensors also exhibit excellent selectivity and long-time stability to acetone.

DFT Study on the (S)-Proline-catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT/6-31G^＊ calculations were applied to study the direct aldol reaction between acetone and 4-nitrobenzaldehyde catalyzed by （S）-proline. Four transition states associated with the stereo-controlling step, corresponding to syn and anti arrangements of methylene moiety related to the carboxylic acid group in enamine intermediate and re and si attacks to the aldehyde carbonyl carbon have been obtained. The solvent effect of DMSO was investigated with polarized continuum model. The computed energies of transition states reveal the stereo-selectivity of the reaction.

VOLTAMMETRIC STUDY ON THE REDUCTION OF RARE EARTHS IN ACETONE

The voltammetric and polarographic behaviours of 14 rare earth elements were investigated in anhydrous acetone.The influence of residual oxygen on their waves was examined.At a concentration lower than 6× 10^(-4)mol/L,Eu^(3+),Yb^(3+)and Sm^(3+) produce two waves and other rare earth ions exhibit only one wave. When the concentration is greater than 8×10^(-4)mol/L,two waves could be observed on the reduction of Yb^(2+),Sm^(2+)and other RE^(3+)ions except for Eu^(3+).By adding 0.6% H_2O(or 1×10^(-4)mol/L NH_4ClO_4) one well-defined wave appears instead of two.The phenomenon is explained that a thin deposit film may be formed at electrode surface owing to the interaction of RE^(3+) with O_2^-,which is the reduction product of trace oxygen in aprotic solvent.In the presence of a proton donor such as H_2O or NH_4^+,oxygen reduces directly to H_2O_2 and eliminates the appearance of two waves.

Acetone Extract of <i>Dioscorea alata</i>Inhibits Cell Proliferation in Cancer Cells

Dioscorea spp., White Yam has been shown to exhibit a wide range of nutritional and medicinal properties. However, the compounds associated with its medicinal functions have not been fully examined. The purpose of this study was to generate a chemoinformatic profile of the bioactive compounds present in Dioscorea. alata (D. alata) and to characterize their putative anti-cancer properties using prostate (DU145) and lung (A549) cancer cells. Chemoinformatic profiling of D. alata resulted in five bioactive extracts: hexane (DaJa-1), ether (DaJa-2), acetone (DaJa-3), ethanol (DaJa-4) and water (DaJa-5) were generated. The analytes present in the five bioactive extracts were dissolved in 0.1% DMSO and their anti-cancer activity were determined. We observed that the acetone extract (DaJa3) was the only extract capable of inducing greater than 90% cell death of DU 145 cell at 100 μg/mL. The order of growth inhibition of the extracts in DU-145 cell is DaJa-3 (IC50, 31.45 μg/mL) > DaJa-4 (IC50 60 μg/mL) > DaJa-1 (IC50 > 100 μg/mL) ≥ DaJa-2 (IC50 > 100 μg/mL) ≥ DaJa-5 (IC50 > 100 μg/mL). MTT cell viability, dye exclusion, caspase activity and microscopic assessment of apoptotic cells demonstrated that DaJa-3 displayed cytotoxicity to both lung and prostate cancer cells. The A549 cells were more sensitive toward DaJa-3 with an IC50 value of 22.28 μg/mL (CI 28.42 to 36.63 μg/mL), compared to that of DU145 cells with an IC50 value of 31.45 μg/mL (CI 27.58 to 35.86 μg/mL). It was also observed that DaJa-3 induces differential anti-proliferative activity in the cancer cells. The apoptotic response induced by DaJa-3 paralleled the level of cell cytotoxicity observed in both cell lines. DaJa-3 induces G2 phase cell cycle arrest in DU145 cells but G1 arrest in A549 cells. The level of key apoptotic regulator proteins was upregulated, suggested that DaJa-3 may be mediating its anti-cancer effect through activation of the intrinsic apoptotic pathway. Altogether, our data indicates that DaJa-3 derived from a staple food source (white Yam) contains unique active compounds that have specific biological properties that may prevent certain types of cancer or specific types of cancer.

Effect of Acetone Vapor Smoothing Process on Surface Finish and Geometric Accuracy of Fused Deposition Modeling ABS Parts

FDM is a widely used additive manufacturing process, however, it has some limitations, such as surface finish, due to the staircase effect caused by the layer-by-layer deposition. Studies have been conducted on surface finish of ABS parts with the use of acetone, but the process parameters and the resulting effects have not been fully investigated in the literature. Therefore, the aim of this study was to investigate the effects of acetone vapor smoothing process on surface finish and geometric accuracy of fused deposition modeling ABS parts. Specimens with different geometries were created and printed using two directions in different scales. The parts were exposed to acetone vapor for 20, 30 and 40 minutes. 3D deviation maps, roughness and microscopic analyses were conducted. The staircase effect was reduced at the expense of some geometric deviations, which varied according to the exposure time and part orientation. The smoothing process applied to the flat surfaces proved to be quite effective in reducing roughness by 90%, however, this reduction led to an undesirable rounding of the sharp edges. The results obtained in this study are consistent with those found in the literature and may help improve the quality of the ABS printed parts.

Crystallization of Amorphous Poly(Lactic Acid) Induced by Vapor of Acetone to Form High Crystallinity and Transparency Specimen

Crystallization of amorphous poly(lactic acid) (PLA) was investigated by exposing to vapor of acetone. The vapor of acetone induced crystallization of the amorphous PLA effectively. It took about 24 min to complete the crystallization of a 1 cm × 2 cm × 0.55 mm specimen at 25℃. The crystallization rate increased with increasing of conducting temperature. The crystallization method yielded high crystallinity about 40%, which was almost equal to that attained by annealing or immersion methods conducted as references. The specimens crystallized by the vapor showed higher transparency than those prepared by the reference methods. The crystallization was induced by diffusion of acetone into the amorphous phase of PLA, and polarized optical photomicrographs cleared that the diffusion obeyed Fick type diffusion.

Investigation of the Structures of the Product Ions Produced via self-CI of Acetone

The ion-molecule reactions in acetone were investigated which were induced under the chemical ionization. The structural information of the reaction products were obtained by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 30eV.

Pd-modified SmFeO_(3)with hollow tubular structure under light shows extremely high acetone gas sensitivity

Currently,SmFeO_(3)-based sensors are an effective platform for detecting acetone gas.However,they require high operating temperatures,which increases energy consumption and safety hazards,and their response is low when the gas concentration is at 10^(-9)(PPB),which cannot meet the requirements of using exhaled breath to pre-diagnose diabetes.Herein,Pd-SmFeO_(3)hollow nanotubes with an extremely high specific surface area and porosity were synthesized by electrospinning.After Pd doping,the specific surface area improved by more than two times,and the acetone response improved by more than three times.In addition,the response further improved by more than 1.5 times,and the optimum operating temperature reduced by 100℃under light irradiation.Moreover,the relative humidity adaptability,long-term stability,and selectivity of the material were significantly improved after Pd doping or light irradiation.Finally,the acetone concentration in a person’s exhaled breath was detected by a Pd-SmFeO_(3)-based gas sensor,and the error was less than 10%compared to that obtained by gas chromatography-mass spectrometry method.

Ultrasensitive room-temperature geranyl acetone detection based on Fe@WO_(3−x) nanoparticles in cooked rice flavor analysis

In the assessment of food quality,geranyl acetone plays a crucial role as a volatile organic compound(VOC)biomarker for diverse agricultural products,while the ultralow concentration detection meeting application requirements has been barely studied.Herein,an iron(Fe)-doped WO_(3−x) gas sensor was employed for greatly sensitive,selective,and scalable geranyl acetone detection.The results proved that precisely-regulated oxygen vacancy(OV)and sophisticatedly-active electron transition of Fe-doped WO_(3−x) nanoparticles were fulfilled by modifying the doping amount of Fe^(3+),leading to the prominently enhanced sensitivity(23.47 at 6 ppm),low limit of detection(LOD)(237 ppb),optimal selectivity,and outstanding long-term stability.Furthermore,the enhancing mechanism of gas sensing performance was substantiated through density functional theory(DFT)calculation,while the practical application for the evaluation of spoiled cooked rice was conducted as well.This study demonstrates a reliable method for detecting a VOC biomarker in cooked rice,which can ensure food security and improve palatability of cooked rice.

Adsorption and desorption of acetone by TiO_(2) clusters:Transition state theory and sensing analysis

TiO_(2) cluster sensitivity to acetone adsorption using transition state theory is investigated.Ti_(10)O_(20) cluster is used to perform the calculations using density functional theory with dispersion corrections.Adsorption state and transition state are calculated via thermodynamic energies,i.e.,Gibbs free energy of adsorption and activation.Reaction rate,response,response time,and recovery time as a function of temperature and acetone concentration are calculated.Acetone burning in the air due to autoignition is considered using a logistic function.The results of the theory are compared with available experimental findings that revealed the quality of both theoretical and experimental results.The response time decreases with respect to acetone concentration.On the other hand,the recovery time in the desorption phase increases with acetone concentration.The temperature of maximum response is 356℃,while the maximum response value is 2.9.