In the first article of this series, we presented some evidence of hyperforin as an antibiotic, antiprotozoal, antiviral, anticancer, and immunomodulatory substance. In the present article, evidence of the permeabilit...In the first article of this series, we presented some evidence of hyperforin as an antibiotic, antiprotozoal, antiviral, anticancer, and immunomodulatory substance. In the present article, evidence of the permeability of the blood-testis barrier (BTB) and blood-brain barrier (BBB) to hyperforin and its distribution in other organs of the domestic pig (Sus scrofa domesticus) are revealed. Seven-month-old male boars with a body mass of 100 kg were fed a diet containing hyperforin. Organs were surgically removed under anesthesia. Organs were suitable prepared and extracted, and then analyzed using gas chromatography-mass spectrometry with supersonic molecular beams (GC-MS with SMB). The presence of hyperforin was recorded in all organs and body fluids. Special attention was paid to the evaluation of the presence of hyperforin in the brain and testes of experimental animals. The presence of hyperforin in the brain and testes of experimental animals was established by GC-MS with SMB. The results are of interest because penicillin and numerous other antibiotics cannot pass through the BTB or BBB if healthy or non-inflamed, which limits their use in patients with meningitis and gonorrhea. The findings are also of interest in cases of penicillin- and multi-antibiotic-resistant bacterial infections.展开更多
Tungsten(W)is an important material in tokamak walls and divertors.The W ion charge state distribution and the dynamic behavior of ions play important roles in the investigation of plasma–wall interactions using lase...Tungsten(W)is an important material in tokamak walls and divertors.The W ion charge state distribution and the dynamic behavior of ions play important roles in the investigation of plasma–wall interactions using laser-ablation-based diagnostics such as laser-induced breakdown spectroscopy and laser-induced ablation spectroscopy.In this work,we investigate the temporal and spatial evolutions of differently charged ions in a nanosecond-laser-produced W plasma in vacuum using time-of-flight mass spectroscopy.Ions with different charge states from 1 to 7(W+to W7+)are all observed.The temporal evolutions of the differently charged ions show that ions with higher charge states have higher velocities,indicating that space separation occurs between the differently charged ion groups.Spatially-resolved mass spectroscopy measurements further demonstrate the separation phenomenon.The temporal profile can be accurately fitted by a shifted Maxwell–Boltzmann distribution,and the velocities of the differently charged ions are also obtained from the fittings.It is found that the ion velocities increase continuously from the measured position of 0.75 cm to 2.25 cm away from the target surface,which indicates that the acceleration process lasts through the period of plasma expansion.The acceleration and space separation of the differently charged ions confirm that there is a dynamic plasma sheath in the laser-produced plasma,which provides essential information for the theoretical laser-ablation model with plasma formation and expansion.展开更多
Trichloromethanesulfenyl thiocyanate, CCl3SSCN, was generated and studied by photoelectron spectroscopy （PES）, photoionization mass spectroscopy （PIMS）, and theoretical calculations. This molecule exhibits a gauch...Trichloromethanesulfenyl thiocyanate, CCl3SSCN, was generated and studied by photoelectron spectroscopy （PES）, photoionization mass spectroscopy （PIMS）, and theoretical calculations. This molecule exhibits a gauche conformation, and the torsional angle around S-S bond is 91.4° due to the sulfur-sulfur lone pair interactions. After ionization, the ground-state cationic-radical form of CCl3SSCN＋ adopts a trans planar main-atom structure with Cs symmetry. The highest occupied molecular orbital （HOMO） of CC13SSCN corresponds to the electrons mainly localized on the sulfur 3p lone pair MO. The first ionization energy is determined to be 10.40 cV.展开更多
The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challengi...The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challenging,which limits the development of advanced electrode materials.Herein,high-resolution mass spectroscopy(HR-MS)is employed to detect the evolution of organic electrode materials during the redox process and reveal the charge storage mechanism,by using small molecular oxamides as an example,which have ortho-carbonyls and are therefore potential electrochemical active materials for batteries.The HR-MS results adequately proved that the oxamides could reversibly store lithium ions in the voltage window of 1.5–3.8 V.Upon deeper reduction,the oxamides would decompose due to the cleavage of the C–N bonds in oxamide structures,which could be proved by the fragments detected by HR-MS,^(1)H NMR,and the generation of NH_(3)after the reduction of oxamide by Li.This work provides a strategy to deeply understand the charge storage mechanism of organic electrode materials and will stimulate the further development of characterization techniques to reveal the charge storage mechanism for developing high-performance electrode materials.展开更多
Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of th...Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment.展开更多
Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1...Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1]H~＋and [L-Ser_6＋ L/D-Thr_2]H~＋were obtained in the range of 2700–3600 cm^（-1）. Chiral differentiation was achieved by comparing their IRPD spectra. The main difference located in the range of 3300–3500 cm^（-1）. And the results indicate the substitution of L-Ser by D-Thr could weaken the intermolecular H-bonds and loosen the original structures of serine octamers.展开更多
Mass spectrometer is connected through an adaptor to a sealed small battery to probe the gas phase changes inside the battery.The factors influencing the response time are analyzed with a simplified model.The feasibil...Mass spectrometer is connected through an adaptor to a sealed small battery to probe the gas phase changes inside the battery.The factors influencing the response time are analyzed with a simplified model.The feasibility of the new technique is demonstrated with a Ni-Cd battery,showing different profiles of MS intensities for O2 and H2.Compared with gas chromatography,this technique has the advantage of being noninvasive and should be useful for the study and diagnostic examination of small sealed batteries.展开更多
Single particle inductively coupled plasma mass spectroscopy(spICP-MS)techniques were first used to analyze individual nano-and microparticles over 20 years ago.1 The“front end”of the instrument has been continually...Single particle inductively coupled plasma mass spectroscopy(spICP-MS)techniques were first used to analyze individual nano-and microparticles over 20 years ago.1 The“front end”of the instrument has been continually refined to bring single particles in a liquid or gaseous stream into a plasma chamber,one by one,where each particle in the plasma becomes a very short-lived cloud of elemental ions which then is analyzed by a time-of-flight mass spectrometer.All atomic components of the particle are observed and identified according to their mass-tocharge ratio.In far less than a millisecond,the composition of the particle is known,and this process continues for as many particle analyses that one wishes to record.Needless to say,massive amounts of data are quickly generated,and machine learning(ML)techniques are used to identify each particle,and in the best case,determine their origin.展开更多
Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal...Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.展开更多
The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_...The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_(3)H_(6)or H_(2)/C_(3)H_(6)as reductants.The Ag/Al_(2)O_(3)catalyst and Cl^(–)-modified Ag/Al_(2)O_(3)catalysts(SA-Cl)were prepared by a conventional impregnation method and characterized by X-ray diffraction,Brunauer-Emmett-Teller isotherm analysis,electron probe microanalysis,transmission electron microscopy,UV-Vis diffuse reflectance spectroscopy,X-ray photoelectron spectroscopy,and hydrogen temperature-programmed reduction.The catalytic activities in the C3H6-SCR and H_(2)/C3H6-SCR reactions were evaluated,and the reaction mechanism was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy and synchrotron vacuum ultraviolet photoionization mass spectroscopy(SVUV-PIMS).We found that Cl^(-)modification of the alumina-supported Ag/Al_(2)O_(3)catalysts facilitated the formation of oxidized silver species(Ag_(n)^(ᵟ+))that catalyze the moderate-temperature oxidation of hydrocarbons into partial oxidation products(mainly acetate species)capable of participating in the SCR reaction.The low-temperature promoting effect of H_(2)on the C3H6-SCR("hydrogen effect")was found to originate from the enhanced decomposition of strongly adsorbed nitrates on the catalyst surface and the conversion of these adsorbed species to–NCO and–CN species.This"H_(2)effect"occurs in the presence of Ag_(n)^(ᵟ+)species rather than the metallic Ag^(0)species.A gaseous intermediate,acrylonitrile(CH_(2)CHCN),was also identified in the H_(2)/C3H6-SCR reaction using SVUV-PIMS.These findings provide novel insights in the structure-activity relationship and reaction mechanisms of the SA-catalyzed HC-SCR reaction of NO.展开更多
Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.a...Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.and their removal is crucial as they have detrimental effects on the environment and human health.The current study focuses on investigating the degradation of pharmaceuticals using a double-chamber microbial fuel cell(MFC).Urine was spiked with four pharmaceuticals(trimethoprim,lamivudine,levofloxacin,and estrone)at a concentration of 2 mg/mL.The MFC was operated for 7 months in batch mode with this spiked urine as feed.The degradation efficiency of the MFC was studied,for which a selective liquid chromatography-tandem mass-spectrometric method was developed for the quantitation of compounds used in the spiking experiments and was validated with a lower limit of quantification of 0.39 ng/mL.The maximum removal rate achieved was 96%±2%.The degradation mechanism involved processes like sorption and anoxic biodegradation.The voltage curve obtained showed that the presence of pharmaceuticals had an initial negative impact on power generation along with increased organic content;however,after the reactor acclimatization,increased power output was achieved with maximum organics removal at 30 h of retention time.This work opens a new perspective for the anoxic biodegradation of pharmaceuticals and can be useful in future bioremediation studies.展开更多
The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions. Hydrogen produced by corrosion in water diffuses into, and reacts with the ...The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions. Hydrogen produced by corrosion in water diffuses into, and reacts with the Mg matrix to form hydride. Some of the hydrogen accumulates at hydride/Mg matrix (or secondary phase) interfaces as a consequence of slow hydride formation and the incompatibility of the hydride with the Mg matrix (or secondary phase), and combines to form molecular hydrogen. This leads to the development of a local pressure at the hydride/Mg matrix (or secondary phase) interface. The expansion stress caused by hydride formation and the local hydrogen pressure due to its accumulation result in brittle fracture of hydride. These two combined effects promote both the corrosion rate of the AZ91 alloy, and crack initiation and propagation even in the absence of an external load. Hydrogen absorption leads to a dramatic deterioration in the mechanical properties of the AZ91 alloy, indicating that hydrogen embrittlement is responsible for transgulanar stress corrosion cracking in aqueous solutions.展开更多
BACKGROUND Pulmonary alveolar proteinosis(PAP)is a pulmonary syndrome wherein large volumes of phospholipid and protein-rich surfactants accumulate within the alveoli.PAP forms include primary(auto-immune PAP),seconda...BACKGROUND Pulmonary alveolar proteinosis(PAP)is a pulmonary syndrome wherein large volumes of phospholipid and protein-rich surfactants accumulate within the alveoli.PAP forms include primary(auto-immune PAP),secondary,and congenital.Nocardiosis is a form of suppurative disease induced upon infection with bacteria of the Nocardia genus.Clinically,cases of PAP complicated with Nocardia infections are rare,regardless of form.Unfortunately,as such,they are easily overlooked or misdiagnosed.We describe,here,the case of a patient suffering from simultaneous primary PAP and nocardiosis.CASE SUMMARY A 45-year-old Chinese man,without history of relevant disease,was admitted to our hospital on August 8,2018 to address complaints of activity-related respiratory exertion and cough lasting over 6 mo.Lung computed tomography(CT)revealed diffuse bilateral lung infiltration with local consolidation in the middle right lung lobe.Subsequent transbronchial lung biopsy and CT-guided lung biopsy led to a diagnosis of primary PAP(granulocyte-macrophage colonystimulating factor antibody-positive)complicated with nocardiosis(periodic acid-Schiff-positive).After a 6 mo course of anti-infective treatment(sulfamethoxazole),the lesion was completely absorbed,such that only fibrous foci remained,and the patient exhibited significant symptom improvement.Followup also showed improvement in pulmonary function and the CT imaging findings of PAP.No whole-lung lavage has been conducted to date.This case highlights that active anti-nocardia treatment may effectively improve the symptoms and alleviate PAP in patients with PAP and nocardia,possibly reducing the need for whole-lung lavage.CONCLUSION When evaluating patients presenting with PAP and pulmonary infections, thepotential for nocardiosis should be considered.展开更多
To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was...To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55% （0.04 g/L） after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy （UPLC-MS）. A mechanism for decolorization of Azure B was proposed as follows： the C=N in Azure B was initially reduced to -NH by nicotinamide adenine dinucleotide phosphate （NADPH）-dependent quinone dehydrogenase, and then the -NH further combined with -OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS 10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.展开更多
Herbal medicines are highly complex and have unknown mechanisms in diseases treatment. Saraca asoca （Roxb.）, De. Wild has been recommended to treat gynecological disorders and used in several commercial polyherbal f...Herbal medicines are highly complex and have unknown mechanisms in diseases treatment. Saraca asoca （Roxb.）, De. Wild has been recommended to treat gynecological disorders and used in several commercial polyherbal formulations. In present study, efforts have been made to explore antimicrobial activity and its co-relation with the distributions of catechins in the organs of S. asoca using targeted MS/MS. Eight extracts （cold and hot water） from four different organs of S. asoca and two drugs were prepared and antimicrobial activity was assessed by microbroth dilution assay. Quantitative and qualitative analysis of catechins in crude extracts was done by using targeted and auto-MS/MS and correlated with antimicrobial activity. （＋）-Catechin and （＋）- epicatechin and their biosynthesis related compound were found to be up-regulated in regenerated bark and leaves extracts. （-）-Epigallocatechin was found to be significantly higher in bark water extract as compared to others but showed low antimicrobial activity. Result showed down- regulation of （-）-epigallocatechin and up-regulation of （＋）-catechin and （＋）-epicatechin in the regenerated bark and leaves of S. asoca. It might be the contributing factor in the antimicrobial activity of regenerated bark and leaves of the plant. The concentration of （＋）-epicatechin in processed drugs （Ashokarishta） from Baidyanath was found to be seven times higher than that of Dabur Pvt. Ltd., but no antimicrobial activity was observed, indicating the variations among the plant based drugs. This will be helpful in rational use of S. asoca parts. Furthermore, the analyticalmethod developed is sensitive, repeatable and reliable; therefore, it is suitable for quality control of herbal drugs.展开更多
The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms...The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms in AgnO- （n--1-8） are inert in the interactions with H2 or D2 at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation （PROX） of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between AgnO- （n=1-8） and H2 were explored using DFT calculations. The results indicated that adsorption of H2 on any site of AgnO- （n=1-8） is extremely weak, and oxidation of H2 by any kind of oxygen in AgnO- （n=1-8） has an apparent barrier strongly dependent on the adsorption style of the ＂O＂. These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.展开更多
Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Sever...Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Several compounds, especially benzene, toluene, p-xylene could only be formed above 500-550℃. Howerver, peak intensities for some pbend derivatives were decreased at the higher temperature. During pyrolysis, for thermo-setting phenol formaldehyde resins, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which leads to a variety of compounds. Addition reactions can also take place among the double-bond compounds during pyrolysis.展开更多
Research for bioactive molecules and not resistant to infectious agents remains topical for science. The total polyphenols (TPP) and total flavonoids (TFv) of the hydroethanolic extracts and fractions obtained were qu...Research for bioactive molecules and not resistant to infectious agents remains topical for science. The total polyphenols (TPP) and total flavonoids (TFv) of the hydroethanolic extracts and fractions obtained were quantified according to the spectrophotometric method described in the literature using the Folin-Ciocalteu reagent and the colorless solutions of sodium nitrite 2.5% and aluminum chloride 10% respectively. The characterization of chemical compounds was made by coupling liquid chromatography (LC) and mass spectroscopy (MS). Thus, 15 chemical compounds were characterized, seven from Gnetum africanum (EBa) and eight from Gnetum buchholzianum (EBb). The majority of which were stilbens, such as Gnetupendin D, Dimethoxygnetulin, Methoxyparvifolol D, Isorhaponcitin from Eba and Gnetuhaidin P, Gnetupendin D, Gnetuhainin C, phenols (Alcohol Homovanillyl, Alcohol Erythro guaiacylglycerol-β-O-4'-coniferyl, and Alcohol Homovanillyl from EBb. The minority were flavonoids such as Dimethoxydihydropyraneriodictyol, Dimethoxyeriodictyol (EBa) and Dimethoxydihydropyraneriodictyol, Trimethoxyluteolin (EBb). The levels of total polyphenolics and total flavonoids content were respectively 14.520 ± 0.557 mg EAA/g Extract and 29.870 ± 2.485 mg EQ/g Extract for EBa. The levels of total polyphenolics and total flavonoids content for EBb were respectively 4.560 ± 0.010 mg EAA/g Extract and 2.233 ± 0.251 mg EQ/g Extract. The high levels of flavonoids content respectively 220.200 ± 35.500 and 335.300 ± 57.810 mg EQ/g Extract were shown in Dichlorometan fraction from EBa and EBb. These bioactive compounds identified and total phenolics compounds quantified can be exploited in pharmacological and pharmacokinetical activities to fight against multi-resistant infectious agents and as well as oxidative stress and antiinflammatory diseases.展开更多
We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy （MBE）, The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-...We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy （MBE）, The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-voltage （l-V） measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 ± 0.03 eV and capture cross-section of 8,57 ×10^-18 cm^2. Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy （SIMS） of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO,展开更多
The diffusion property of sulfur on the soda-lime-silicate float glass surface was studied by using secondary ion mass spectroscopy（SIMS）.According to the Fick＇s Second Law,two models of diffusion of sulfur on the ...The diffusion property of sulfur on the soda-lime-silicate float glass surface was studied by using secondary ion mass spectroscopy（SIMS）.According to the Fick＇s Second Law,two models of diffusion of sulfur on the glass surface were built.When the diffusion of sulfate（S^6＋） is considered uniquely,the concentration-depth profile of sulfur can not be fitted very well,especially on the top surfaces of the air side and tin side of float glass.So the diffusion of sulfide（S^2-） on the profile of sulfur can not be ignored.The concentration-depth profile of sulfur on both sides of glass can be fitted more exactly when both S^6＋ and S^2- are considerd.Based on the above-mentioned fitting results,it is concluded that the diffusion coefficents of S^6＋ and S^2- of tin side are larger than those of the air side.Moreover,the diffusion coefficents are related to the contacted medium.展开更多
文摘In the first article of this series, we presented some evidence of hyperforin as an antibiotic, antiprotozoal, antiviral, anticancer, and immunomodulatory substance. In the present article, evidence of the permeability of the blood-testis barrier (BTB) and blood-brain barrier (BBB) to hyperforin and its distribution in other organs of the domestic pig (Sus scrofa domesticus) are revealed. Seven-month-old male boars with a body mass of 100 kg were fed a diet containing hyperforin. Organs were surgically removed under anesthesia. Organs were suitable prepared and extracted, and then analyzed using gas chromatography-mass spectrometry with supersonic molecular beams (GC-MS with SMB). The presence of hyperforin was recorded in all organs and body fluids. Special attention was paid to the evaluation of the presence of hyperforin in the brain and testes of experimental animals. The presence of hyperforin in the brain and testes of experimental animals was established by GC-MS with SMB. The results are of interest because penicillin and numerous other antibiotics cannot pass through the BTB or BBB if healthy or non-inflamed, which limits their use in patients with meningitis and gonorrhea. The findings are also of interest in cases of penicillin- and multi-antibiotic-resistant bacterial infections.
基金supported by the National Key R&D Program of China(No.2017YFE0301304)National Natural Science Foundation of China(No.12005034)the China Postdoctoral Science Foundation(No.2019M661087)supported by the US Department of Energy,Office of Defense Nuclear Nonproliferation Research and Development,under contract number DE-AC02-05CH11231 at the Lawrence Berkeley National Laboratory。
文摘Tungsten(W)is an important material in tokamak walls and divertors.The W ion charge state distribution and the dynamic behavior of ions play important roles in the investigation of plasma–wall interactions using laser-ablation-based diagnostics such as laser-induced breakdown spectroscopy and laser-induced ablation spectroscopy.In this work,we investigate the temporal and spatial evolutions of differently charged ions in a nanosecond-laser-produced W plasma in vacuum using time-of-flight mass spectroscopy.Ions with different charge states from 1 to 7(W+to W7+)are all observed.The temporal evolutions of the differently charged ions show that ions with higher charge states have higher velocities,indicating that space separation occurs between the differently charged ion groups.Spatially-resolved mass spectroscopy measurements further demonstrate the separation phenomenon.The temporal profile can be accurately fitted by a shifted Maxwell–Boltzmann distribution,and the velocities of the differently charged ions are also obtained from the fittings.It is found that the ion velocities increase continuously from the measured position of 0.75 cm to 2.25 cm away from the target surface,which indicates that the acceleration process lasts through the period of plasma expansion.The acceleration and space separation of the differently charged ions confirm that there is a dynamic plasma sheath in the laser-produced plasma,which provides essential information for the theoretical laser-ablation model with plasma formation and expansion.
基金This work was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences （No.KZCX2-YW-205） and the Hundred Talents Fund, the 973 Program of Ministry of Science and Technology of China （No.2006CB403701）, and the National Natural Science Foundation of China （No.20577052, No.20673123, No.20473094, and No.20503035）.
文摘Trichloromethanesulfenyl thiocyanate, CCl3SSCN, was generated and studied by photoelectron spectroscopy （PES）, photoionization mass spectroscopy （PIMS）, and theoretical calculations. This molecule exhibits a gauche conformation, and the torsional angle around S-S bond is 91.4° due to the sulfur-sulfur lone pair interactions. After ionization, the ground-state cationic-radical form of CCl3SSCN＋ adopts a trans planar main-atom structure with Cs symmetry. The highest occupied molecular orbital （HOMO） of CC13SSCN corresponds to the electrons mainly localized on the sulfur 3p lone pair MO. The first ionization energy is determined to be 10.40 cV.
基金financialy supported by the National Natural Science Foundation of China(52173163,22279038,and 22205069)the National 1000-Talents Program,the Innovation Fund of WNLO,the Open Fund of the State Key Laboratory of Integrated Optoelectronics(IOSKL2020KF02)+1 种基金Wenzhou Science&Technology Bureau(ZG2022020,G20220022,and G20220026)the China Postdoctoral Science Foundation(2021TQ0115,2021 M701302,and 2020 M672323)
文摘The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challenging,which limits the development of advanced electrode materials.Herein,high-resolution mass spectroscopy(HR-MS)is employed to detect the evolution of organic electrode materials during the redox process and reveal the charge storage mechanism,by using small molecular oxamides as an example,which have ortho-carbonyls and are therefore potential electrochemical active materials for batteries.The HR-MS results adequately proved that the oxamides could reversibly store lithium ions in the voltage window of 1.5–3.8 V.Upon deeper reduction,the oxamides would decompose due to the cleavage of the C–N bonds in oxamide structures,which could be proved by the fragments detected by HR-MS,^(1)H NMR,and the generation of NH_(3)after the reduction of oxamide by Li.This work provides a strategy to deeply understand the charge storage mechanism of organic electrode materials and will stimulate the further development of characterization techniques to reveal the charge storage mechanism for developing high-performance electrode materials.
文摘Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment.
基金Financial support from the National Natural Science Foundation of China(No.21475065)
文摘Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1]H~＋and [L-Ser_6＋ L/D-Thr_2]H~＋were obtained in the range of 2700–3600 cm^（-1）. Chiral differentiation was achieved by comparing their IRPD spectra. The main difference located in the range of 3300–3500 cm^（-1）. And the results indicate the substitution of L-Ser by D-Thr could weaken the intermolecular H-bonds and loosen the original structures of serine octamers.
基金supported by National Natural Science Foundation of China(Project No.29833090)The authors thank Professor Chuan Sin CHA for suggesting this experiment and helpful discussions.
文摘Mass spectrometer is connected through an adaptor to a sealed small battery to probe the gas phase changes inside the battery.The factors influencing the response time are analyzed with a simplified model.The feasibility of the new technique is demonstrated with a Ni-Cd battery,showing different profiles of MS intensities for O2 and H2.Compared with gas chromatography,this technique has the advantage of being noninvasive and should be useful for the study and diagnostic examination of small sealed batteries.
文摘Single particle inductively coupled plasma mass spectroscopy(spICP-MS)techniques were first used to analyze individual nano-and microparticles over 20 years ago.1 The“front end”of the instrument has been continually refined to bring single particles in a liquid or gaseous stream into a plasma chamber,one by one,where each particle in the plasma becomes a very short-lived cloud of elemental ions which then is analyzed by a time-of-flight mass spectrometer.All atomic components of the particle are observed and identified according to their mass-tocharge ratio.In far less than a millisecond,the composition of the particle is known,and this process continues for as many particle analyses that one wishes to record.Needless to say,massive amounts of data are quickly generated,and machine learning(ML)techniques are used to identify each particle,and in the best case,determine their origin.
文摘Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.
文摘The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_(3)H_(6)or H_(2)/C_(3)H_(6)as reductants.The Ag/Al_(2)O_(3)catalyst and Cl^(–)-modified Ag/Al_(2)O_(3)catalysts(SA-Cl)were prepared by a conventional impregnation method and characterized by X-ray diffraction,Brunauer-Emmett-Teller isotherm analysis,electron probe microanalysis,transmission electron microscopy,UV-Vis diffuse reflectance spectroscopy,X-ray photoelectron spectroscopy,and hydrogen temperature-programmed reduction.The catalytic activities in the C3H6-SCR and H_(2)/C3H6-SCR reactions were evaluated,and the reaction mechanism was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy and synchrotron vacuum ultraviolet photoionization mass spectroscopy(SVUV-PIMS).We found that Cl^(-)modification of the alumina-supported Ag/Al_(2)O_(3)catalysts facilitated the formation of oxidized silver species(Ag_(n)^(ᵟ+))that catalyze the moderate-temperature oxidation of hydrocarbons into partial oxidation products(mainly acetate species)capable of participating in the SCR reaction.The low-temperature promoting effect of H_(2)on the C3H6-SCR("hydrogen effect")was found to originate from the enhanced decomposition of strongly adsorbed nitrates on the catalyst surface and the conversion of these adsorbed species to–NCO and–CN species.This"H_(2)effect"occurs in the presence of Ag_(n)^(ᵟ+)species rather than the metallic Ag^(0)species.A gaseous intermediate,acrylonitrile(CH_(2)CHCN),was also identified in the H_(2)/C3H6-SCR reaction using SVUV-PIMS.These findings provide novel insights in the structure-activity relationship and reaction mechanisms of the SA-catalyzed HC-SCR reaction of NO.
文摘Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.and their removal is crucial as they have detrimental effects on the environment and human health.The current study focuses on investigating the degradation of pharmaceuticals using a double-chamber microbial fuel cell(MFC).Urine was spiked with four pharmaceuticals(trimethoprim,lamivudine,levofloxacin,and estrone)at a concentration of 2 mg/mL.The MFC was operated for 7 months in batch mode with this spiked urine as feed.The degradation efficiency of the MFC was studied,for which a selective liquid chromatography-tandem mass-spectrometric method was developed for the quantitation of compounds used in the spiking experiments and was validated with a lower limit of quantification of 0.39 ng/mL.The maximum removal rate achieved was 96%±2%.The degradation mechanism involved processes like sorption and anoxic biodegradation.The voltage curve obtained showed that the presence of pharmaceuticals had an initial negative impact on power generation along with increased organic content;however,after the reactor acclimatization,increased power output was achieved with maximum organics removal at 30 h of retention time.This work opens a new perspective for the anoxic biodegradation of pharmaceuticals and can be useful in future bioremediation studies.
基金supported by the Hundred Talent Program of the Chinese Academy of Sciences,the National Natural Science Foundation of China(No.50499336)the National Basic Research Program of China(No.2007CB613705)
文摘The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions. Hydrogen produced by corrosion in water diffuses into, and reacts with the Mg matrix to form hydride. Some of the hydrogen accumulates at hydride/Mg matrix (or secondary phase) interfaces as a consequence of slow hydride formation and the incompatibility of the hydride with the Mg matrix (or secondary phase), and combines to form molecular hydrogen. This leads to the development of a local pressure at the hydride/Mg matrix (or secondary phase) interface. The expansion stress caused by hydride formation and the local hydrogen pressure due to its accumulation result in brittle fracture of hydride. These two combined effects promote both the corrosion rate of the AZ91 alloy, and crack initiation and propagation even in the absence of an external load. Hydrogen absorption leads to a dramatic deterioration in the mechanical properties of the AZ91 alloy, indicating that hydrogen embrittlement is responsible for transgulanar stress corrosion cracking in aqueous solutions.
文摘BACKGROUND Pulmonary alveolar proteinosis(PAP)is a pulmonary syndrome wherein large volumes of phospholipid and protein-rich surfactants accumulate within the alveoli.PAP forms include primary(auto-immune PAP),secondary,and congenital.Nocardiosis is a form of suppurative disease induced upon infection with bacteria of the Nocardia genus.Clinically,cases of PAP complicated with Nocardia infections are rare,regardless of form.Unfortunately,as such,they are easily overlooked or misdiagnosed.We describe,here,the case of a patient suffering from simultaneous primary PAP and nocardiosis.CASE SUMMARY A 45-year-old Chinese man,without history of relevant disease,was admitted to our hospital on August 8,2018 to address complaints of activity-related respiratory exertion and cough lasting over 6 mo.Lung computed tomography(CT)revealed diffuse bilateral lung infiltration with local consolidation in the middle right lung lobe.Subsequent transbronchial lung biopsy and CT-guided lung biopsy led to a diagnosis of primary PAP(granulocyte-macrophage colonystimulating factor antibody-positive)complicated with nocardiosis(periodic acid-Schiff-positive).After a 6 mo course of anti-infective treatment(sulfamethoxazole),the lesion was completely absorbed,such that only fibrous foci remained,and the patient exhibited significant symptom improvement.Followup also showed improvement in pulmonary function and the CT imaging findings of PAP.No whole-lung lavage has been conducted to date.This case highlights that active anti-nocardia treatment may effectively improve the symptoms and alleviate PAP in patients with PAP and nocardia,possibly reducing the need for whole-lung lavage.CONCLUSION When evaluating patients presenting with PAP and pulmonary infections, thepotential for nocardiosis should be considered.
基金supported by the Science&Technology Program of Jiangsu Province(No.BE2011623)the Scientific Research Project of Provincial Environmental Protection Bureau of Jiangsu Province(No.2012047)
文摘To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55% （0.04 g/L） after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy （UPLC-MS）. A mechanism for decolorization of Azure B was proposed as follows： the C=N in Azure B was initially reduced to -NH by nicotinamide adenine dinucleotide phosphate （NADPH）-dependent quinone dehydrogenase, and then the -NH further combined with -OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS 10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.
基金supported by Central Council for Research in Ayurvedic Sciences(CCRAS),Department of AYUSH,Government of India
文摘Herbal medicines are highly complex and have unknown mechanisms in diseases treatment. Saraca asoca （Roxb.）, De. Wild has been recommended to treat gynecological disorders and used in several commercial polyherbal formulations. In present study, efforts have been made to explore antimicrobial activity and its co-relation with the distributions of catechins in the organs of S. asoca using targeted MS/MS. Eight extracts （cold and hot water） from four different organs of S. asoca and two drugs were prepared and antimicrobial activity was assessed by microbroth dilution assay. Quantitative and qualitative analysis of catechins in crude extracts was done by using targeted and auto-MS/MS and correlated with antimicrobial activity. （＋）-Catechin and （＋）- epicatechin and their biosynthesis related compound were found to be up-regulated in regenerated bark and leaves extracts. （-）-Epigallocatechin was found to be significantly higher in bark water extract as compared to others but showed low antimicrobial activity. Result showed down- regulation of （-）-epigallocatechin and up-regulation of （＋）-catechin and （＋）-epicatechin in the regenerated bark and leaves of S. asoca. It might be the contributing factor in the antimicrobial activity of regenerated bark and leaves of the plant. The concentration of （＋）-epicatechin in processed drugs （Ashokarishta） from Baidyanath was found to be seven times higher than that of Dabur Pvt. Ltd., but no antimicrobial activity was observed, indicating the variations among the plant based drugs. This will be helpful in rational use of S. asoca parts. Furthermore, the analyticalmethod developed is sensitive, repeatable and reliable; therefore, it is suitable for quality control of herbal drugs.
文摘The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms in AgnO- （n--1-8） are inert in the interactions with H2 or D2 at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation （PROX） of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between AgnO- （n=1-8） and H2 were explored using DFT calculations. The results indicated that adsorption of H2 on any site of AgnO- （n=1-8） is extremely weak, and oxidation of H2 by any kind of oxygen in AgnO- （n=1-8） has an apparent barrier strongly dependent on the adsorption style of the ＂O＂. These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.
文摘Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Several compounds, especially benzene, toluene, p-xylene could only be formed above 500-550℃. Howerver, peak intensities for some pbend derivatives were decreased at the higher temperature. During pyrolysis, for thermo-setting phenol formaldehyde resins, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which leads to a variety of compounds. Addition reactions can also take place among the double-bond compounds during pyrolysis.
文摘Research for bioactive molecules and not resistant to infectious agents remains topical for science. The total polyphenols (TPP) and total flavonoids (TFv) of the hydroethanolic extracts and fractions obtained were quantified according to the spectrophotometric method described in the literature using the Folin-Ciocalteu reagent and the colorless solutions of sodium nitrite 2.5% and aluminum chloride 10% respectively. The characterization of chemical compounds was made by coupling liquid chromatography (LC) and mass spectroscopy (MS). Thus, 15 chemical compounds were characterized, seven from Gnetum africanum (EBa) and eight from Gnetum buchholzianum (EBb). The majority of which were stilbens, such as Gnetupendin D, Dimethoxygnetulin, Methoxyparvifolol D, Isorhaponcitin from Eba and Gnetuhaidin P, Gnetupendin D, Gnetuhainin C, phenols (Alcohol Homovanillyl, Alcohol Erythro guaiacylglycerol-β-O-4'-coniferyl, and Alcohol Homovanillyl from EBb. The minority were flavonoids such as Dimethoxydihydropyraneriodictyol, Dimethoxyeriodictyol (EBa) and Dimethoxydihydropyraneriodictyol, Trimethoxyluteolin (EBb). The levels of total polyphenolics and total flavonoids content were respectively 14.520 ± 0.557 mg EAA/g Extract and 29.870 ± 2.485 mg EQ/g Extract for EBa. The levels of total polyphenolics and total flavonoids content for EBb were respectively 4.560 ± 0.010 mg EAA/g Extract and 2.233 ± 0.251 mg EQ/g Extract. The high levels of flavonoids content respectively 220.200 ± 35.500 and 335.300 ± 57.810 mg EQ/g Extract were shown in Dichlorometan fraction from EBa and EBb. These bioactive compounds identified and total phenolics compounds quantified can be exploited in pharmacological and pharmacokinetical activities to fight against multi-resistant infectious agents and as well as oxidative stress and antiinflammatory diseases.
文摘We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy （MBE）, The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-voltage （l-V） measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 ± 0.03 eV and capture cross-section of 8,57 ×10^-18 cm^2. Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy （SIMS） of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO,
基金Funded by National Natural Science Foundation of China(NSFC)(No.50972136)National Science and Technology S upporting P rogram(No.2015BAA02B00)+1 种基金National Key Technologies R&D Program(No.2016YFB0303900)the Fundamental Research Funds of State Key Laboratory for Advanced Technology of Float Glass
文摘The diffusion property of sulfur on the soda-lime-silicate float glass surface was studied by using secondary ion mass spectroscopy（SIMS）.According to the Fick＇s Second Law,two models of diffusion of sulfur on the glass surface were built.When the diffusion of sulfate（S^6＋） is considered uniquely,the concentration-depth profile of sulfur can not be fitted very well,especially on the top surfaces of the air side and tin side of float glass.So the diffusion of sulfide（S^2-） on the profile of sulfur can not be ignored.The concentration-depth profile of sulfur on both sides of glass can be fitted more exactly when both S^6＋ and S^2- are considerd.Based on the above-mentioned fitting results,it is concluded that the diffusion coefficents of S^6＋ and S^2- of tin side are larger than those of the air side.Moreover,the diffusion coefficents are related to the contacted medium.
