Laser-induced breakdown spectroscopy was employed to determine the inorganic elements in coal. To improve the measurement's accuracy and precision, a new internal standardization scheme, which we named changed intern...Laser-induced breakdown spectroscopy was employed to determine the inorganic elements in coal. To improve the measurement's accuracy and precision, a new internal standardization scheme, which we named changed internal standardization, was compared with the traditional internal standardization and no internal standardization for the analysis of inorganic elements. The new internal standardization scheme used the atomic line of carbon at 247.86 nm and the molecular band of CN at 388.34 nm and C2 at 516.32 nm to normalize the lines of inorganic elements that were distributed in the same spectral channel. The performance of the utilization of the new internal standardization scheme was evaluated using a set of coal samples, including twenty calibration samples and five validation samples. The results show that the coefficients of determination R2 and the slope of calibration models coupled with changed internal standard- ization are better than that of the calibration models coupled with fixed internal standardization and no internal standardization. Moreover, the measurement accuracy and reproducibility of changed internal standardization for the analysis of five validation samples also yielded further improvement. The results that we obtained suggest that changed internal standardization could compensate for the matrix effects, as well as the influence of the difference in the spectral response of the light collection system.展开更多
Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level ...Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level of instrumental stability required for the analysis process and provides a valid solution for high-precision and accurate studies of Si isotopic compositions. Rock samples were dissolved by using alkali fusion and acidification. Silicon isotopes were purified with an ion exchange resin. Interfering peaks for isotopes were separated by using a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometry (MS) system in high-resolution mode (M/AM 〉 8000 RP). Two magnesium isotopes (25Mg and 26Mg) and three silicon isotopes (28Si, 29Si, and 3;Si) were analyzed in the same data collection cycle. Mg isotopes were used as an internal standard to calibrate the mass discrimination effects in MS analysis of Si isotopes in combination with the SSB method in order to reduce the effects of MS interference and instrumental mass dis- crimination on the accuracy of measurements. The conventional SSB method without the Mg internal standard and the proposed SSB method with Mg calibration delivered consistent results within two standard deviations. When Mg was used as an internal standard for calibration, the analysis precision was better than 0.05 %0 amu.展开更多
The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of ...The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of an internal standard allows for the correction of losses due to sample clean-up of complex samples. An ideal IS is a compound that has properties very similar to, and that behaves as the compounds to be analysed. Ideally, only in the last step of analysis (HPLC), the IS should be well separated from the compounds of the mixture to be analysed. After testing several existing compounds with negative results, we decided to synthesise the 19-O-β-D-galactopyranosyl-13-O-β-D-glucopyranosyl-steviol as IS. This is the 19-galactosyl ester of steviolmonoside (13-O-β-D-glucopyranosyl-steviol). The IS was made according to published methods. Steviolmonoside (SM) was made from purified commercial rubusoside (Rub) by refluxing it in 10% KOH for 2 h. SM was precipitated and crystallized from MeOH. The hydroxyls of the glucose unit of SM were protected by acetylation. The acetylated SM was crystallized from acetone and dissolved in 1,2-dichloroethane. Then Ag2CO3 on Celite and tetra-acetylated galactopyranosyl bromide were added and the mixture was refluxed for 2 h. After cooling, BaO in MeOH was added to remove the acetyl groups. The 1,2-dichloroethane fraction was then extracted three times with equal volumes of water and the water fraction containing the IS was further purified on a C18 flash chromatography column. Traces of unreacted SM were removed by preparative HPLC on an Alltima C18 column (250 mm × 22 mm, particle size 10 μm) with AcCN:water (35:65, 20 ml/min). Detection was at 210 nm (KNAUER, “Smartline” UV detector 2500). The collected IS fraction from the HPLC was completely dried. Mixtures of steviol glycosides (SVglys) containing IS could be purified over SPE cartridges without change of the SVgly over IS ratio. The calibration curves for rebaudioside A (RebA) and stevioside (ST) were linear between 0.012 and 0.95 and between 0.013 and 1.13 mM for RebA and ST, respectively. The accuracy was checked by the standard addition method. It was concluded that the IS method gives an excellent precision and accuracy.展开更多
Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and ...Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and a modified constant-sum (MCS) method. Methods were then compared for reported bulk elemental composition of the rocks. The MCS method was based on the sum of eight major elements, which is spatially more stable than one single major ele-ment as used in the IS method, and is quite constant among different rock samples. Calibrations were performed with standard reference materials NIST SRM 610, 612, 614, and 616. Little difference was found between using a single standard and a set of standards, because of the good linearity shown by the reference materials. Comparison of the two calibration methods shows that the MCS method produced better and more stable results than the IS method for heterogeneous samples. With the MCS method, approximately 94% to 95% of the total measurements are within the range of ±100% relative deviation, compared with 82% to 86% with the IS method. The IS method resulted insubstantial overestimations for some rock samples (e.g., 648% for Basalt BCR-2 using NIST SRM 610 as the calibration standard), while the largest deviation with the MCS method was 216% for U in Eagle Ford shale #80 sample. For Quartz latite QLO-1, a relative homogeneous sample, the IS method generated slightly better results than the MCS method. Regardless of method, spatially heterogeneous distribution of elements in the intact rock at the scale of the laser spot is considered to be the main reason for the large relative deviations seen in our work compared to published results.展开更多
The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLD...The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.展开更多
[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solven...[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solvent and maleic acid as internal standard under the conditions of temperature 25℃,pulses width 8.0μs,delay time 5 s,and scanning times 8.[Result]The hydrogen proton peaks of tetrachlorantraniliprole(δ=10.55)and maleic acid(δ=6.27)were taken as quantitative peaks.The peak area ratio y(As/Ar)and mass ratio x(ms/mr)were linearly regressed,and the correlation coefficient was 0.9999.The RSD value of repeatability test was 0.38%,and the RSD value of stability test was 0.77%.The content of tetrachlorantraniliprole was determined as 99.6%.[Conclusion]1H NMR spectroscopy can be used for quantitative determination of tetrachlorantraniliprole without standard reference,which is rapid,accurate and simple.展开更多
In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters (¢at 12 mm and 16 mm) were tested under varying tension forces and it was concluded that 90 N is the rational one. What...In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters (¢at 12 mm and 16 mm) were tested under varying tension forces and it was concluded that 90 N is the rational one. What’s more, the smal er drip-irrigation inner diameter, the thinner wal thickness, and the higher tension force, the lower acceptability, and the larger drip-irrigation inner diameter, the thicker wal thickness, and the lower tension force, the higher acceptability. The causes were analyzed in the research, including manufacturing technique leading to disqualifica-tion and different specifications with the same demands on techniques, and inadap-tation to tension force at 130 N.展开更多
The induction motor,which converts electrical energy into mechanical energy,has been recognized as the cornerstone of industrialization.The rotor of an induction motor can be either a squirrel cage rotor or a wound-ty...The induction motor,which converts electrical energy into mechanical energy,has been recognized as the cornerstone of industrialization.The rotor of an induction motor can be either a squirrel cage rotor or a wound-type rotor,both existing as magnetless topologies.Three-phase squirrel cage induction motors are frequently utilized in industrial drives because they are dependable,have high starting torque,are selfstarting and affordable.Single-phase induction motors,on the other hand,are commonly used for small loads such as domestic appliances in form of modest fans,pumps and electric power tools.In South Africa,there have been reports of fires and explosions resulting in live and property loss because of induction motors that have not been thoroughly tested or are incorrectly labelled in terms of ratings,electrical safety and performance.The goal of this study is targeted at preventing end-user injuries and failures caused by non-compliant induction motors,by evaluating locally manufactured/imported induction motors based on tests and evaluation from standards(IEC and SANS).The study is conducted using experimental procedures at the Explosion Prevention Technology and Rotating Machines(EPT and RM)laboratory,South African Bureau of Standards(SABS),South Africa.The main finding from the study shows differences in the nameplate characteristics of various induction motors which could have detrimental effects such as production and operational downtime in their end-use industries,at later stages.展开更多
The simulated patient methodology(SPM)is considered the“gold standard”as covert participatory observation.SPM is attracting increasing interest for the investigation of community pharmacy practice;however,there is c...The simulated patient methodology(SPM)is considered the“gold standard”as covert participatory observation.SPM is attracting increasing interest for the investigation of community pharmacy practice;however,there is criticism that SPM can only show a small picture of everyday pharmacy practice and therefore has limited external validity.On the one hand,a certain design and application of the SPM goes hand in hand with an increase in external validity.Even if,on the other hand,this occurs at the expense of internal validity due to the trade-off situation,the justified criticism of the SPM for investigating community pharmacy practice can be countered.展开更多
The SubBytes (S-box) transformation is the most crucial operation in the AES algorithm, significantly impacting the implementation performance of AES chips. To design a high-performance S-box, a segmented optimization...The SubBytes (S-box) transformation is the most crucial operation in the AES algorithm, significantly impacting the implementation performance of AES chips. To design a high-performance S-box, a segmented optimization implementation of the S-box is proposed based on the composite field inverse operation in this paper. This proposed S-box implementation is modeled using Verilog language and synthesized using Design Complier software under the premise of ensuring the correctness of the simulation result. The synthesis results show that, compared to several current S-box implementation schemes, the proposed implementation of the S-box significantly reduces the area overhead and critical path delay, then gets higher hardware efficiency. This provides strong support for realizing efficient and compact S-box ASIC designs.展开更多
The specific mechanisms by which acupuncture affects the central nervous system are unclear. In the International Standard Scalp Acupuncture system, acupuncture needles are applied at the middle line of the vertex, an...The specific mechanisms by which acupuncture affects the central nervous system are unclear. In the International Standard Scalp Acupuncture system, acupuncture needles are applied at the middle line of the vertex, anterior parietal-temporal oblique line, and the posterior parietal-temporal oblique line. We conducted a single-arm prospective clinical trial in which seven healthy elderly volunteers (three men and four women;50–70 years old) received International Standard Scalp Acupuncture at MS5 (the mid-sagittal line between Baihui (DU20) and Qianding (DU21)), the left MS6 (line joining Sishencong (EX-HN1) and Xuanli (GB6)), and the left MS7 (line joining DU20 and Qubin (GB7)). After acupuncture, resting-state functional magnetic resonance imaging demonstrated changes in the fractional amplitude of low frequency fluctuations and regional homogeneity in various areas, showing remarkable enhancement of regional homogeneity in the bilateral anterior cingulate, left medial frontal gyrus, supramarginal gyrus, right middle frontal gyrus, and inferior frontal gyrus. Functional connectivity based on a seed region at the right middle frontal gyrus (42, 51, 9) decreased at the bilateral medial superior frontal gyrus. Our data preliminarily indicates that the international standard scalp acupuncture in healthy elderly participants specifcally enhances the correlation between the brain regions involved in cognition and implementation of the brain network regulation system and the surrounding adjacent brain regions. The study was approved by the Ethics Committee of the China-Japan Union Hospital at Jilin University, China, on July 18, 2016 (approval No. 2016ks043).展开更多
Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to con...Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to consumers. One such innovation is the Meat Standards Australia(MSA) system. This system is a Total Quality Management System, aimed at delivering an eating quality guarantee to consumers, and through this adding value to the entire supply chain. At present, it is well developed for beef and still evolving for sheepmeat. MSA has identified Critical Control Points(CCPs) in the production, pre-slaughter, processing and value-adding aspects of the supply chain that impact on consumer palatability through the large-scale taste testing of meat by untrained consumers. These CCPs are used as either(1) mandatory criteria determining eligibility for grading, and(2) inputs in a model predicting the palatability of individual combinations of muscle and different cooking methods. Through the prediction of palatability, MSA increases consumer satisfaction and is used to provide assurance for branded products and new marketing innovations in Australia and internationally. This has added significant value to the Australian beef industry, with several retail examples demonstrating consumer willingness to pay more for premium quality beef and sheepmeat products based on the MSA grading scores. This price differential at retail allows the value of the carcass to be calculated based on the eating quality as well as the volume produced, thereby delivering a financial reward for farmers producing high quality carcasses. The continuous quality scale of MSA allows producers to realise the financial gain of incremental improvements in quality, as well as the precise economic weights associated with traits such as marbling, ossification score, or breed. The use of MSA in this fashion has underpinned a new and innovative supply chain where the pricing is transparent and allows producers to make informed decisions to modify both quality and yield traits. To date, the MSA system for beef has proved to be effective in predicting beef palatability not only in Australia but also in many other countries(France, Poland, Ireland, Northern Ireland, Japan, South Korea, New-Zealand, the USA and South Africa). In Europe, results of the Pro Safe Beef and Pro Opti Beef projects as well as other national projects demonstrate the potential to develop an MSA-like international grading system for the supply chain in the EU, despite thediverse cultures and complex beef production systems within the member states. International testing in lamb has only just begun and preliminary results are discussed here.展开更多
This papcr presents a comparison between the Chinese Code GB50011-2001 and the International Standard ISO3010:2001(E),emphasizing the similarities and differences related to design requirements,seismic actions and ana...This papcr presents a comparison between the Chinese Code GB50011-2001 and the International Standard ISO3010:2001(E),emphasizing the similarities and differences related to design requirements,seismic actions and analytical approaches.Similarities include:earthquake return period,conceptual design,site classification,structural strength and ductility requirements,deformation limits,response spectra,seismic analysis procedures,isolation and energy dissipation, and nonstructural elements.Differences exist in the following areas:seismic levels,earthquake loading,mode damping factors and structural control.展开更多
The ultimate need to account for the partial amount of energy deposited in target tissue/organ resulting from internal inhalation,ingestion,and injection intakes of radionuclides,defined by the Medical Internal Radiat...The ultimate need to account for the partial amount of energy deposited in target tissue/organ resulting from internal inhalation,ingestion,and injection intakes of radionuclides,defined by the Medical Internal Radiation Dosimetry committee as the specific absorbed fraction(SAF),has become obvious.In this study,we assessed the SAF values for self-and cross-absorption,which were calculated for a uniform distribution of monoenergetic photon and electron emitters with energies ranging from 15 keV to 3 MeV.The voxelized human phantom‘‘High-Definition Reference Korean-man’’(HDRK-man),which was implemented using the Monte Carlo simulation code GEANT4(version 10.1),was used for several combinations of target–source organs.The results were compared to those of the International Commission on Radiological Protection Reference(ICRP133)and Zubal phantoms.It was found that the SAF values of the three models have a similar trend.However,the SAF values for the HDRK-man phantom were higher than those of the other two models,with a relatively good agreement with those for the ICRP133 phantom(differences of 13.9±2.8 and 12.1±3.2 for photon and electron emitters,respectively).To analyze the differences in SAF values,we calculated the chord length distributions(CLDs)for selected target–source combinations.The parameters of organ mass(or volume)and CLDs,in addition to the adopted computational procedures,mainly cause such discrepancies.For realistic radionuclide emission spectra,an overall overestimation was observed when computing the S values for three radiopharmaceuticals studied(I-131,In-111,and Lu-177)and for liver–spleen intra-and inter-organ absorption when compared with published data.The new arrangement of S and SAF values is expected to add value for multidisciplinary research and clinical communities.展开更多
AIMTo evaluate Jordanian ophthalmology residency programs in achieving competencies outlined by the International Council of Ophthalmology (ICO) and residents' satisfaction with available training programs in Jord...AIMTo evaluate Jordanian ophthalmology residency programs in achieving competencies outlined by the International Council of Ophthalmology (ICO) and residents' satisfaction with available training programs in Jordan, and to highlight weakness points that may be improved and strengthened.展开更多
Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide...Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide(CBA). Previous studies have shownthat both polymers had high transfection efficiencies as gene delivery carriers. In this study,we investigated the nucleolus localization abilities and cellular internalization pathways ofthese two polymers in gene delivery. Each polymer condensed plasmid DNA(p DNA) andformed nanoparticle complexes, and then their transfection studies were performed inMCF-7 cells. Both complexes were found enriched in nucleolus after cellular transfection,and their transfection efficiencies were significantly improved when transfection was per-formed on MCF-7 cells arrested at M phase. The transfection efficiency of CAR-CBA-pDNAwas inhibited by chlorpromazine, and cell endosomes were disrupted after being exposedto CAR-CBA-pDNA. In regards to CHL-CBA-pDNA, its transfection efficiency was not affected by three types of endocytosis inhibitors used in the study, and CHL-CBA-pDNA showed no effect on endosomes. Cellular lactate dehydrogenase release and membrane morphology were changed after cells were transfected by the two complexes. The results indicated that both CAR-CBA and CHL-CBA polymers demonstrated good nucleolus localization abilities. It was beneficial for transfection when cells were arrested at M phase. CAR-CBA-pDNA cellular internalization was involved with clathrin-mediated endocytosis pathway, and escaping from endosomal entrapment, while the cellular uptake of CHL-CBA-pDNA occurs via clathrin-and caveolae-independent mechanism.展开更多
As one of the most concerned digital technologies in recent years,blockchain and distributed ledger technology are an important driving force for a new round of technological development.It is currently in the process...As one of the most concerned digital technologies in recent years,blockchain and distributed ledger technology are an important driving force for a new round of technological development.It is currently in the process of accelerating its evolution and maturity,and has gradually integrated with other digital technologies.It has been applied in many industries,providing decentralized solutions for various industries,realizing innovative storage models,and building a new trust system.As blockchain technology is officially incorporated into China’s new information infrastructure category,the application fields of blockchain have expanded rapidly,gradually extending from the financial field and government affairs to other fields in the real economy.At the same time,with the continuous development of the globalized economy,blockchain technology will also have a profound impact on international technological and economic development.Therefore,for the healthy and orderly development and real implementation of the blockchain industry,standardize the application of blockchain,effectively break through the cognitive and technical barriers between different countries,industries and systems on a global scale,prevent application risks,the development of the global blockchain industry needs standardization basis,which is particularly important and urgent.A sound standard system is an important key to the successful development of technology,and formulating the right standard at the right time for technology development helps ensure the ease of use and interoperability of the technology.From the perspective of international standardization,this article first introduces the general situation of ISO,ITU-T,IEEE,W3C and other international standardization organizations,and sorts out the status quo of the blockchain standardization working groups of mainstream international standardization organizations.All blockchain-related standards under development have been analyzed for the characteristics of international blockchain technology standards and industry application standards.Through data analysis,the overlaps,differences and conflicts in the field of international blockchain standard formulation are sorted out,and suggestions for blockchain standardization work in the application and development of blockchain technology standardization by international organizations and industries are put forward.The plans and layouts of future international standards are summarized to help the development of the international standardization of blockchain.展开更多
Sequence variation of the first internal transcribed spacer of ribosomal DNA ( ITS - 1 ) was examined and its application to the study of genetic variation was explored in four populations of farter' s scallop Chla...Sequence variation of the first internal transcribed spacer of ribosomal DNA ( ITS - 1 ) was examined and its application to the study of genetic variation was explored in four populations of farter' s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA (analysis of molecular variance) showed that the majority (96.26%) of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 ( = 0.042), indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly.展开更多
Lemierre’s syndrome(LS)is an uncommon condition with oropharyngeal infections,internal jugular vein thrombosis,and systemic metastatic septic embolization as the main features.Fusobacterium species,a group of strictl...Lemierre’s syndrome(LS)is an uncommon condition with oropharyngeal infections,internal jugular vein thrombosis,and systemic metastatic septic embolization as the main features.Fusobacterium species,a group of strictly anaerobic Gram negative rod shaped bacteria,are advocated to be the main pathogen involved.We report a case of LS complicated by pulmonary embolism and pulmonary septic emboli that mimicked a neoplastic lung condition.A Medline search revealed 173 case reports of LS associated with internal jugular vein thrombosis that documented the type of microorganism.Data confirmed high prevalence in young males with Gram negative infections(83.2%).Pulmonary embolism was reported in 8.7% of cases mainly described in subjects with Gram positive infections(OR=9.786;95%CI:2.577-37.168,P=0.001),independently of age and gender.Only four fatal cases were reported.LS is an uncommon condition that could be complicated by pulmonary embolism,especially in subjects with Gram positive infections.展开更多
基金supported by Open Research Fund of State Key Laboratory of Pulsed Power Laser Technology of China(No.SKL2013KF03)National Natural Science Foundation of China(Nos.51206055,51476061)+3 种基金the Fundamental Research Funds for the Central Universities of China(No.2014ZZ0014)the New Star of Pearl River on Science and Technology of Guangzhou,China(No.2014J2200054)the Key Laboratory of Efficient and Clean Energy Utilization of Guangdong Higher Education Institutes of China(No.KLB10004)Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization,China(No.2013A061401005)
文摘Laser-induced breakdown spectroscopy was employed to determine the inorganic elements in coal. To improve the measurement's accuracy and precision, a new internal standardization scheme, which we named changed internal standardization, was compared with the traditional internal standardization and no internal standardization for the analysis of inorganic elements. The new internal standardization scheme used the atomic line of carbon at 247.86 nm and the molecular band of CN at 388.34 nm and C2 at 516.32 nm to normalize the lines of inorganic elements that were distributed in the same spectral channel. The performance of the utilization of the new internal standardization scheme was evaluated using a set of coal samples, including twenty calibration samples and five validation samples. The results show that the coefficients of determination R2 and the slope of calibration models coupled with changed internal standard- ization are better than that of the calibration models coupled with fixed internal standardization and no internal standardization. Moreover, the measurement accuracy and reproducibility of changed internal standardization for the analysis of five validation samples also yielded further improvement. The results that we obtained suggest that changed internal standardization could compensate for the matrix effects, as well as the influence of the difference in the spectral response of the light collection system.
基金funded by the National Natural Science Foundation of China(Grant Nos.41427804,41421002,41373004)Beijing SHRIMP Center Open Foundation,and Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT1281)the MOST Research Foundation from the State Key Laboratory of Continental Dynamics(BJ08132-1)
文摘Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level of instrumental stability required for the analysis process and provides a valid solution for high-precision and accurate studies of Si isotopic compositions. Rock samples were dissolved by using alkali fusion and acidification. Silicon isotopes were purified with an ion exchange resin. Interfering peaks for isotopes were separated by using a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometry (MS) system in high-resolution mode (M/AM 〉 8000 RP). Two magnesium isotopes (25Mg and 26Mg) and three silicon isotopes (28Si, 29Si, and 3;Si) were analyzed in the same data collection cycle. Mg isotopes were used as an internal standard to calibrate the mass discrimination effects in MS analysis of Si isotopes in combination with the SSB method in order to reduce the effects of MS interference and instrumental mass dis- crimination on the accuracy of measurements. The conventional SSB method without the Mg internal standard and the proposed SSB method with Mg calibration delivered consistent results within two standard deviations. When Mg was used as an internal standard for calibration, the analysis precision was better than 0.05 %0 amu.
文摘The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of an internal standard allows for the correction of losses due to sample clean-up of complex samples. An ideal IS is a compound that has properties very similar to, and that behaves as the compounds to be analysed. Ideally, only in the last step of analysis (HPLC), the IS should be well separated from the compounds of the mixture to be analysed. After testing several existing compounds with negative results, we decided to synthesise the 19-O-β-D-galactopyranosyl-13-O-β-D-glucopyranosyl-steviol as IS. This is the 19-galactosyl ester of steviolmonoside (13-O-β-D-glucopyranosyl-steviol). The IS was made according to published methods. Steviolmonoside (SM) was made from purified commercial rubusoside (Rub) by refluxing it in 10% KOH for 2 h. SM was precipitated and crystallized from MeOH. The hydroxyls of the glucose unit of SM were protected by acetylation. The acetylated SM was crystallized from acetone and dissolved in 1,2-dichloroethane. Then Ag2CO3 on Celite and tetra-acetylated galactopyranosyl bromide were added and the mixture was refluxed for 2 h. After cooling, BaO in MeOH was added to remove the acetyl groups. The 1,2-dichloroethane fraction was then extracted three times with equal volumes of water and the water fraction containing the IS was further purified on a C18 flash chromatography column. Traces of unreacted SM were removed by preparative HPLC on an Alltima C18 column (250 mm × 22 mm, particle size 10 μm) with AcCN:water (35:65, 20 ml/min). Detection was at 210 nm (KNAUER, “Smartline” UV detector 2500). The collected IS fraction from the HPLC was completely dried. Mixtures of steviol glycosides (SVglys) containing IS could be purified over SPE cartridges without change of the SVgly over IS ratio. The calibration curves for rebaudioside A (RebA) and stevioside (ST) were linear between 0.012 and 0.95 and between 0.013 and 1.13 mM for RebA and ST, respectively. The accuracy was checked by the standard addition method. It was concluded that the IS method gives an excellent precision and accuracy.
文摘Laser ablation coupled with inductively coupled plasma-mass spectrometry (LA-ICP-MS) calibration was conducted with multiple spot analyses on eleven intact rock samples using both an internal standard (IS) method and a modified constant-sum (MCS) method. Methods were then compared for reported bulk elemental composition of the rocks. The MCS method was based on the sum of eight major elements, which is spatially more stable than one single major ele-ment as used in the IS method, and is quite constant among different rock samples. Calibrations were performed with standard reference materials NIST SRM 610, 612, 614, and 616. Little difference was found between using a single standard and a set of standards, because of the good linearity shown by the reference materials. Comparison of the two calibration methods shows that the MCS method produced better and more stable results than the IS method for heterogeneous samples. With the MCS method, approximately 94% to 95% of the total measurements are within the range of ±100% relative deviation, compared with 82% to 86% with the IS method. The IS method resulted insubstantial overestimations for some rock samples (e.g., 648% for Basalt BCR-2 using NIST SRM 610 as the calibration standard), while the largest deviation with the MCS method was 216% for U in Eagle Ford shale #80 sample. For Quartz latite QLO-1, a relative homogeneous sample, the IS method generated slightly better results than the MCS method. Regardless of method, spatially heterogeneous distribution of elements in the intact rock at the scale of the laser spot is considered to be the main reason for the large relative deviations seen in our work compared to published results.
基金supported by National Key Research and Development Program of China(2019YFC1606400)Science and Technology Project of State Administration for Market Regulation(2021MK023)+1 种基金Hebei Province High-level Talent Funding Program(A201901008)Research Project of Hebei Administration for Market Regulation(2020ZD12)。
文摘The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.
文摘[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solvent and maleic acid as internal standard under the conditions of temperature 25℃,pulses width 8.0μs,delay time 5 s,and scanning times 8.[Result]The hydrogen proton peaks of tetrachlorantraniliprole(δ=10.55)and maleic acid(δ=6.27)were taken as quantitative peaks.The peak area ratio y(As/Ar)and mass ratio x(ms/mr)were linearly regressed,and the correlation coefficient was 0.9999.The RSD value of repeatability test was 0.38%,and the RSD value of stability test was 0.77%.The content of tetrachlorantraniliprole was determined as 99.6%.[Conclusion]1H NMR spectroscopy can be used for quantitative determination of tetrachlorantraniliprole without standard reference,which is rapid,accurate and simple.
文摘In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters (¢at 12 mm and 16 mm) were tested under varying tension forces and it was concluded that 90 N is the rational one. What’s more, the smal er drip-irrigation inner diameter, the thinner wal thickness, and the higher tension force, the lower acceptability, and the larger drip-irrigation inner diameter, the thicker wal thickness, and the lower tension force, the higher acceptability. The causes were analyzed in the research, including manufacturing technique leading to disqualifica-tion and different specifications with the same demands on techniques, and inadap-tation to tension force at 130 N.
基金supported in part by Explosion Prevention Technology and Rotating Machines(EPT&RM)laboratory,South African Bureau of Standards(SABS),Pretoria,South Africa.
文摘The induction motor,which converts electrical energy into mechanical energy,has been recognized as the cornerstone of industrialization.The rotor of an induction motor can be either a squirrel cage rotor or a wound-type rotor,both existing as magnetless topologies.Three-phase squirrel cage induction motors are frequently utilized in industrial drives because they are dependable,have high starting torque,are selfstarting and affordable.Single-phase induction motors,on the other hand,are commonly used for small loads such as domestic appliances in form of modest fans,pumps and electric power tools.In South Africa,there have been reports of fires and explosions resulting in live and property loss because of induction motors that have not been thoroughly tested or are incorrectly labelled in terms of ratings,electrical safety and performance.The goal of this study is targeted at preventing end-user injuries and failures caused by non-compliant induction motors,by evaluating locally manufactured/imported induction motors based on tests and evaluation from standards(IEC and SANS).The study is conducted using experimental procedures at the Explosion Prevention Technology and Rotating Machines(EPT and RM)laboratory,South African Bureau of Standards(SABS),South Africa.The main finding from the study shows differences in the nameplate characteristics of various induction motors which could have detrimental effects such as production and operational downtime in their end-use industries,at later stages.
文摘The simulated patient methodology(SPM)is considered the“gold standard”as covert participatory observation.SPM is attracting increasing interest for the investigation of community pharmacy practice;however,there is criticism that SPM can only show a small picture of everyday pharmacy practice and therefore has limited external validity.On the one hand,a certain design and application of the SPM goes hand in hand with an increase in external validity.Even if,on the other hand,this occurs at the expense of internal validity due to the trade-off situation,the justified criticism of the SPM for investigating community pharmacy practice can be countered.
文摘The SubBytes (S-box) transformation is the most crucial operation in the AES algorithm, significantly impacting the implementation performance of AES chips. To design a high-performance S-box, a segmented optimization implementation of the S-box is proposed based on the composite field inverse operation in this paper. This proposed S-box implementation is modeled using Verilog language and synthesized using Design Complier software under the premise of ensuring the correctness of the simulation result. The synthesis results show that, compared to several current S-box implementation schemes, the proposed implementation of the S-box significantly reduces the area overhead and critical path delay, then gets higher hardware efficiency. This provides strong support for realizing efficient and compact S-box ASIC designs.
基金funded by the National Natural Science Foundation of China,No.81403455(to JQC)
文摘The specific mechanisms by which acupuncture affects the central nervous system are unclear. In the International Standard Scalp Acupuncture system, acupuncture needles are applied at the middle line of the vertex, anterior parietal-temporal oblique line, and the posterior parietal-temporal oblique line. We conducted a single-arm prospective clinical trial in which seven healthy elderly volunteers (three men and four women;50–70 years old) received International Standard Scalp Acupuncture at MS5 (the mid-sagittal line between Baihui (DU20) and Qianding (DU21)), the left MS6 (line joining Sishencong (EX-HN1) and Xuanli (GB6)), and the left MS7 (line joining DU20 and Qubin (GB7)). After acupuncture, resting-state functional magnetic resonance imaging demonstrated changes in the fractional amplitude of low frequency fluctuations and regional homogeneity in various areas, showing remarkable enhancement of regional homogeneity in the bilateral anterior cingulate, left medial frontal gyrus, supramarginal gyrus, right middle frontal gyrus, and inferior frontal gyrus. Functional connectivity based on a seed region at the right middle frontal gyrus (42, 51, 9) decreased at the bilateral medial superior frontal gyrus. Our data preliminarily indicates that the international standard scalp acupuncture in healthy elderly participants specifcally enhances the correlation between the brain regions involved in cognition and implementation of the brain network regulation system and the surrounding adjacent brain regions. The study was approved by the Ethics Committee of the China-Japan Union Hospital at Jilin University, China, on July 18, 2016 (approval No. 2016ks043).
基金the Sheep Cooperative Research Centre(CRC)for Sheep Industry Innovation,and associated organisations for funding and data collection support
文摘Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to consumers. One such innovation is the Meat Standards Australia(MSA) system. This system is a Total Quality Management System, aimed at delivering an eating quality guarantee to consumers, and through this adding value to the entire supply chain. At present, it is well developed for beef and still evolving for sheepmeat. MSA has identified Critical Control Points(CCPs) in the production, pre-slaughter, processing and value-adding aspects of the supply chain that impact on consumer palatability through the large-scale taste testing of meat by untrained consumers. These CCPs are used as either(1) mandatory criteria determining eligibility for grading, and(2) inputs in a model predicting the palatability of individual combinations of muscle and different cooking methods. Through the prediction of palatability, MSA increases consumer satisfaction and is used to provide assurance for branded products and new marketing innovations in Australia and internationally. This has added significant value to the Australian beef industry, with several retail examples demonstrating consumer willingness to pay more for premium quality beef and sheepmeat products based on the MSA grading scores. This price differential at retail allows the value of the carcass to be calculated based on the eating quality as well as the volume produced, thereby delivering a financial reward for farmers producing high quality carcasses. The continuous quality scale of MSA allows producers to realise the financial gain of incremental improvements in quality, as well as the precise economic weights associated with traits such as marbling, ossification score, or breed. The use of MSA in this fashion has underpinned a new and innovative supply chain where the pricing is transparent and allows producers to make informed decisions to modify both quality and yield traits. To date, the MSA system for beef has proved to be effective in predicting beef palatability not only in Australia but also in many other countries(France, Poland, Ireland, Northern Ireland, Japan, South Korea, New-Zealand, the USA and South Africa). In Europe, results of the Pro Safe Beef and Pro Opti Beef projects as well as other national projects demonstrate the potential to develop an MSA-like international grading system for the supply chain in the EU, despite thediverse cultures and complex beef production systems within the member states. International testing in lamb has only just begun and preliminary results are discussed here.
文摘This papcr presents a comparison between the Chinese Code GB50011-2001 and the International Standard ISO3010:2001(E),emphasizing the similarities and differences related to design requirements,seismic actions and analytical approaches.Similarities include:earthquake return period,conceptual design,site classification,structural strength and ductility requirements,deformation limits,response spectra,seismic analysis procedures,isolation and energy dissipation, and nonstructural elements.Differences exist in the following areas:seismic levels,earthquake loading,mode damping factors and structural control.
文摘The ultimate need to account for the partial amount of energy deposited in target tissue/organ resulting from internal inhalation,ingestion,and injection intakes of radionuclides,defined by the Medical Internal Radiation Dosimetry committee as the specific absorbed fraction(SAF),has become obvious.In this study,we assessed the SAF values for self-and cross-absorption,which were calculated for a uniform distribution of monoenergetic photon and electron emitters with energies ranging from 15 keV to 3 MeV.The voxelized human phantom‘‘High-Definition Reference Korean-man’’(HDRK-man),which was implemented using the Monte Carlo simulation code GEANT4(version 10.1),was used for several combinations of target–source organs.The results were compared to those of the International Commission on Radiological Protection Reference(ICRP133)and Zubal phantoms.It was found that the SAF values of the three models have a similar trend.However,the SAF values for the HDRK-man phantom were higher than those of the other two models,with a relatively good agreement with those for the ICRP133 phantom(differences of 13.9±2.8 and 12.1±3.2 for photon and electron emitters,respectively).To analyze the differences in SAF values,we calculated the chord length distributions(CLDs)for selected target–source combinations.The parameters of organ mass(or volume)and CLDs,in addition to the adopted computational procedures,mainly cause such discrepancies.For realistic radionuclide emission spectra,an overall overestimation was observed when computing the S values for three radiopharmaceuticals studied(I-131,In-111,and Lu-177)and for liver–spleen intra-and inter-organ absorption when compared with published data.The new arrangement of S and SAF values is expected to add value for multidisciplinary research and clinical communities.
基金Supported in part by an unrestricted grant from Research to Prevent Blindness,Inc.New York,N.Y,USA
文摘AIMTo evaluate Jordanian ophthalmology residency programs in achieving competencies outlined by the International Council of Ophthalmology (ICO) and residents' satisfaction with available training programs in Jordan, and to highlight weakness points that may be improved and strengthened.
基金supported by National Natural Science Foundation of China (Grant no. 81373335)
文摘Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide(CBA). Previous studies have shownthat both polymers had high transfection efficiencies as gene delivery carriers. In this study,we investigated the nucleolus localization abilities and cellular internalization pathways ofthese two polymers in gene delivery. Each polymer condensed plasmid DNA(p DNA) andformed nanoparticle complexes, and then their transfection studies were performed inMCF-7 cells. Both complexes were found enriched in nucleolus after cellular transfection,and their transfection efficiencies were significantly improved when transfection was per-formed on MCF-7 cells arrested at M phase. The transfection efficiency of CAR-CBA-pDNAwas inhibited by chlorpromazine, and cell endosomes were disrupted after being exposedto CAR-CBA-pDNA. In regards to CHL-CBA-pDNA, its transfection efficiency was not affected by three types of endocytosis inhibitors used in the study, and CHL-CBA-pDNA showed no effect on endosomes. Cellular lactate dehydrogenase release and membrane morphology were changed after cells were transfected by the two complexes. The results indicated that both CAR-CBA and CHL-CBA polymers demonstrated good nucleolus localization abilities. It was beneficial for transfection when cells were arrested at M phase. CAR-CBA-pDNA cellular internalization was involved with clathrin-mediated endocytosis pathway, and escaping from endosomal entrapment, while the cellular uptake of CHL-CBA-pDNA occurs via clathrin-and caveolae-independent mechanism.
基金supported by the Key R&D Program of Zhejiang Province(2021C01105)the Key R&D Program of Guangdong Province(2020B0101090003)+1 种基金the National Key R&D Program of China(2021YFB2701100)These supports are gratefully acknowledged.
文摘As one of the most concerned digital technologies in recent years,blockchain and distributed ledger technology are an important driving force for a new round of technological development.It is currently in the process of accelerating its evolution and maturity,and has gradually integrated with other digital technologies.It has been applied in many industries,providing decentralized solutions for various industries,realizing innovative storage models,and building a new trust system.As blockchain technology is officially incorporated into China’s new information infrastructure category,the application fields of blockchain have expanded rapidly,gradually extending from the financial field and government affairs to other fields in the real economy.At the same time,with the continuous development of the globalized economy,blockchain technology will also have a profound impact on international technological and economic development.Therefore,for the healthy and orderly development and real implementation of the blockchain industry,standardize the application of blockchain,effectively break through the cognitive and technical barriers between different countries,industries and systems on a global scale,prevent application risks,the development of the global blockchain industry needs standardization basis,which is particularly important and urgent.A sound standard system is an important key to the successful development of technology,and formulating the right standard at the right time for technology development helps ensure the ease of use and interoperability of the technology.From the perspective of international standardization,this article first introduces the general situation of ISO,ITU-T,IEEE,W3C and other international standardization organizations,and sorts out the status quo of the blockchain standardization working groups of mainstream international standardization organizations.All blockchain-related standards under development have been analyzed for the characteristics of international blockchain technology standards and industry application standards.Through data analysis,the overlaps,differences and conflicts in the field of international blockchain standard formulation are sorted out,and suggestions for blockchain standardization work in the application and development of blockchain technology standardization by international organizations and industries are put forward.The plans and layouts of future international standards are summarized to help the development of the international standardization of blockchain.
基金This work was financially supported by the"863"Project of China under contract No.2002AA626020the National Nalural Science Foundation of China under contract No.30570242.
文摘Sequence variation of the first internal transcribed spacer of ribosomal DNA ( ITS - 1 ) was examined and its application to the study of genetic variation was explored in four populations of farter' s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA (analysis of molecular variance) showed that the majority (96.26%) of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 ( = 0.042), indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly.
文摘Lemierre’s syndrome(LS)is an uncommon condition with oropharyngeal infections,internal jugular vein thrombosis,and systemic metastatic septic embolization as the main features.Fusobacterium species,a group of strictly anaerobic Gram negative rod shaped bacteria,are advocated to be the main pathogen involved.We report a case of LS complicated by pulmonary embolism and pulmonary septic emboli that mimicked a neoplastic lung condition.A Medline search revealed 173 case reports of LS associated with internal jugular vein thrombosis that documented the type of microorganism.Data confirmed high prevalence in young males with Gram negative infections(83.2%).Pulmonary embolism was reported in 8.7% of cases mainly described in subjects with Gram positive infections(OR=9.786;95%CI:2.577-37.168,P=0.001),independently of age and gender.Only four fatal cases were reported.LS is an uncommon condition that could be complicated by pulmonary embolism,especially in subjects with Gram positive infections.