Equidistant combination wavelength screening and step-by-step phase-out method for the near-infrared spectroscopic analysis of serum urea nitrogen

We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.

UV/visible spectroscopic analysis of CO^(3+) and CO^(2+) during the dissolution of cobalt from mixed Co-Cu oxidized ores

The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores with diluted H2SO4 and SO2 as a reducing agent resulted in a substantial improvement in the solution based recovery of cobalt. UV/visible spectroscopic analysis of the leached solu-tions indicated that the increased cobalt content in the solution was a result of flushing the acidified cobalt leaching solution with SO2. Fur-thermore, UV/visible spectroscopy confirmed that as SO2 was flushed into the acidified leaching solution, Co3＋ bearing minerals were re-duced to the readily soluble Co2＋ bearing minerals, and this resulted in the increase of total cobalt in the collected solution. The mechanism of the reduction of Co3＋ to Co2＋ bearing minerals when SO2 is flushed during the leaching of mixed Co-Cu oxidized ores, including the stability trends of Co3＋, Co2＋, and Cu2＋ complexes, as shown by their UV/visible spectra, are also discussed.

Vibrational Spectroscopic Analysis of Borates in Mother Liquid of Brine after Potassium Separated

It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization

Spectroscopic Analysis of Spherical Graphite from Xinjiang Altai

1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high capacitor material,with a high cost performance(Chuan et al,2012).Spherical

An integrated spectroscopic strategy to trace the geographical origins of emblic medicines: Application for the quality assessment of natural medicines

Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation.A rapid and effective geographical traceability system has not been designed yet.To trace the geographical origins so that their quality can be controlled,an integrated spectroscopic strategy including spectral pretreatment,outlier diagnosis,feature selection,data fusion,and machine learning algorithm was proposed.A featured data matrix(245
220)was successfully generated,and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model.The results demonstrate that the proposed strategy is effective and can be generalized.Sensitivity(SEN),specificity(SPE)and accuracy(ACC)of 97.65%,99.85%and 97.63%for the calibrated set,as well as 100.00%predictive efficiency,were obtained using this spectroscopic analysis strategy.Our study has created an integrated analysis process for multiple spectral data,which can achieve a rapid,nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.

Near-Infrared Spectroscopy Combined with Absorbance Upper Optimization Partial Least Squares Applied to Rapid Analysis of Polysaccharide for Proprietary Chinese Medicine Oral Solution

Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L-1 and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods.

Moving-window bis-correlation coefficients method for visible and near-infrared spectral discriminant analysis with applications

The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The well-performed moving window principal component analysis linear discriminant analysis(MWPCA-LDA)was also conducted for comparison.A total of 306 transgenic(positive)and 150 nont ransgenic(negative)leave samples of sugarcane were collected and divided to calibration,prediction,and validation.The diffuse reflection spectra were corected using Savitzky-Golay(SG)smoothing with first-order derivative(d=1),third-degree polynomial(p=3)and 25 smpothing points(m=25).The selected waveband was 736-1054nm with MW-BiCC,and the positive and negative validation recognition rates(V_REC^(+),VREC^(-))were 100%,98.0%,which achieved the same effect as MWPCA-LDA.Another example,the 93 B-thalassemia(positive)and 148 nonthalassemia(negative)of human hemolytic samples were colloctod.The transmission spectra were corrected using SG smoothing withd=1,p=3 and m=53.Using M W-BiCC,many best wavebands were selected(e.g.,1116-1146,17941848 and 22842342nm).The V_REC^(+)and V_REC^(-)were both 100%,which achieved the same effect as MW-PCA-LDA.Importantly,the BICC only required ca lculating correlation cofficients between the spectrum of prediction sample and the average spectra of two types of calibration samples.Thus,BiCC was very simple in algorithm,and expected to obtain more applications.The results first confirmed the feasibility of distinguishing B-thalassemia and normal control samples by NIR spectroscopy,and provided a promising simple tool for large population thalassemia screening.

Kinematics and stellar population properties of the Andromeda galaxy by using the spectroscopic observations of the Guoshoujing Telescope

The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.

Spectroscopic Measurement of Neutral Particle Influx Ratio on EAST

The spectra of HeI（587.6 nm）,Hα（656.28 nm） and Dα（656.1 nm） of the helium discharges as well as the normal deuterium discharges have been measured with two optical spectroscopic multi-channel analysis（OMA） systems on the experimental advanced superconducting tokamak（EAST）.The influx ratio of the sum of H and D to He spectral lines and the influx ratio of H to D are given.In this way the ratio of hydrogen/deuterium ion（S/X B）H/D to（S/X B）He as well as（S/X B）H/D is not very sensitive to the variation in the edge density and temperature. The low-density helium discharges are operated in order to reduce the recycling hydrogen fluxes; however,the effect is not obvious.The possible reason is that the number of helium discharges is not enough and the content of hydrogen in the wall is still very abundant,which is caused by frequent wall conditionings and the vacuum leakage.The H/（H＋D） ratio decreases quickly after one lithium coating and reduces to less than 10%using several accumulated lithium wall conditioning.It is found that the deposited He atoms on the carbon wall will remain at a low level after several D2 discharges.

Mapping and compositional analysis of mare basalts in the Aristarchus region of the Moon using Clementine data

The process of accurately defining and outlining mare basalt units is nec- essary for constraining the stratigraphy and ages of basalt units, which are used to determine the duration and the flux of lunar volcanism. We use a combination of Clementine＇s five-band ultraviolet/visible data and Ti02 and FeO abundance distri- bution maps to define homogenous mare basalt units and characterize their composi- tional variations （with maturity） in the Aristarchus region. With 20 groups of distinct mare basaltic soils identified using the method in this paper, six additional spectrally defined areas and five basaltic units are constructed, and their mineralogic quanfiza- tion values provide new constraints on their temporal and spatial evolution. Our results indicate that the Aristarchus region has diverse basalt units and a complex history of volcanic evolution. We also demonstrate that the techniques, from which spectrally distinct mare basalts can be mapped, performed well in this study and can be confi- dently expanded to other mare regions of the Moon.

A search for strongly Mg-enhanced stars from the Sloan Digital Sky Survey

Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution （R≈2000） spectra from the Sloan Digital Sky Survey （SDSS） is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic （HRS） analysis by Nissen ＆ Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters （M92, M 13, M3, M71） which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.

Study on the Ternary Heteropolyacids in the Systems of P-Mo-W and As-Mo-W as well as their Application in the Spectrophotometric Determination of Low Tungsten

The colored associated compounds of phosphomolybdotungstate and arsenomolybdotungstate with crystal violet are introduced. Their main characters have been studied. These two associated compounds may be used to determine low tungsten with fairly high sensitivity and selectivity. Their strong point is that the interference of molybdenum can be overcome. In the presence of polyvinyl alcohol, tungsten can be determined directly in the aqueous solution.

XPS Study on the Valence of Thulium in Its Ternary Iodides

By using XPS method the valence of thulium in ternary iodides CsTmI3, Cs2TmI4, RbTmI3 and KTmI3 has been studied. The identification of the valence of thulium in these compounds was made by comparing the observed chemical shift of Tm4d bonding energy with those of thulium in TmI2 and TmI3. The results indicate that the thulium in its ternary iodides has a valence of +2.

The effect of salinity on Fucus ceranoides (Ochrophyta,Phaeophyceae) in the Mondego River(Portugal)

Algae(and their extracts)are increasingly important for pharmaceutical applications due to the diversity of useful compounds they contain.The genus Fucus contains one of the most studied species,Fucus vesiculosus.The species F.ceranoides differs from the others of the genus by presenting longitudinal air-vesicles and a capacity to survive at low salinities.It is an alga that inhabits the Mondego River estuary(Portugal),at the southern limit of its distribution,and can serve as a role model to understand the effect of a salt gradient on the production of bioactive compounds.We assessed the phenolic content and antioxidant activity of different F.ceranoides extracts(e.g.methanolic,aqueous and polysaccharide)prepared from samples harvested from two different zones to evaluate if the adaptation of F.ceranoides to different salinity levels influenced its chemical composition.The antioxidant activity of the extracts was determined using 1,2-diphenyl-picrylhydrazyl(DPPH)and 2.2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radicals.These assays demonstrated that the methanolic extract of lyophilized F.ceranoides that grew at low salinities was the most bioactive,i.e.DPPH(IC 50=50.39μg/mL)and ABTS(TEAC=2.42).The total phenolic content(Folin-Ciocalteu method)and the methanolic extract of the lyophilized F.ceranoides collected from a low salinity habitat exhibited the highest phenolic content(PGE=49.48μg/mg of lyophilized extract)amongst those sampled.Thin layer chromatography(TLC)and Fourier transform infrared spectroscopy(FTIR)were used for the identification of compounds in the extracts.This characterization allowed confirmation that the various extracts contained almost the same compounds but with notable quantitative differences.Based on these results,we conclude that there were differences in the quantity of the compounds due to the effect of salinity.The drying methods used were also found to have influenced the quality of the extracted compounds.

Simultaneous Determination of Uranium and Thorium with Standard Dual-addition Method

dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultaneous determination of uranium and thorium without prior separation. Various molar ratios of uranium/thorium, from 0.5∶1 to 10∶1, can be determined with satisfactory precision and accuracy. Uranium and thorium content in a phosphate ore and simulated sample were determined, the recoveries were 98.4%～102.5% for uranium and 96.8%～102.3% for thorium, the relative standard deviations (R.S.D) were 1.5%～2.3% for uranium and 2.1%～3.1% for thorium.

Determination of Crystal Structure of Britholite-Y

Britholite-Y is milkwhite, rosy in colour. The measured specific gravity is 4.35, with Ng′ = 1.791, Np′ = 1.784. As determined by electron microprobe, its crystal formula is (Y2.82Ca1.58Ce0.27Dy0.21Er0.11)5 [(Si2.95P0.05)3O12](OH,F), space group = C22-P21, a = (0.9504±0.0005) nm, b = (0.9414±0.0004) nm, c = (0.6922±0.0002) nm, r = (119.71±0.04)°, V = (53.79±0.04) nm3, Z = 2. Least-squares refinements with 2272 independent reflection (F0>3σ|F0|) yielded R = 0.111. The change of symmetry group P63/m of apatite to P21 of britholite-Y results from the shifts of Y, Ca, Si, O and (OH) atoms (anions) from the pseudohexagonal P63/m equivalent positions (6h), (4f), (12i) and (2a) as produced by distortion of the polyhedra with 7-, 9-, and 4-corners. The substitution of Ca in apatite for Y and the order distribution of atoms Y and Ca on the equivalent positions (6h) and (4f) have contributed to the distortion of 7- and 9- cornered polyhedra. The substitutions of Si4+ for P5+ and OH- for F- may also be effected. The crystal chemistry of apatite-group minerals is also discussed.

AO-MW-PLS method applied to rapid quantification of teicoplanin with near-infrared spectroscopy

Teicoplanin(TCP)is an important lipoglycopeptide antibiotic produced by fermenting Acti-noplanes teichomyceticus.The change in TCP concentration is important to measure in the fermentation process.In this study,a reagent-free and rapid quantification method for TCP in the TCP-Tris-HCl mixture samples was developed using near infrared(NIR)spectroscopy by focusing our attention on the fermentation process for TCP.The absorbance optimization(AO)partial least squares(PLS)was proposed and integrated with the moving window(MW)PLS,which is called AO-MW-PLS method,to select appropriate wavebands.Amodel set that includes various wavebands that were equivalent to the optimal AO-MW-PLS waveband was,proposed based on statistical considerations.The public region of all equivalent wavebands was just one of the equivalent wavebands.The obtained public regions were 1540-1868 nm for TCP and 1114-1310 nm for Tris.The root-mean-square error and correlation coeficient for leave-one-out cross validation were 0.046 mg mL^(-1)and 0.9998 mg mL^(-1)for TCP,and 0.235 mg mL^(-1)and 0.9986 mg mL^(-1)for Tris,respectively.All the models achieved highly accurate prediction effects,and the selected wavebands provided valuable references for designing specialized spectrometers.This study provided a valuable reference for further application of the proposed methods to TCP fermentation broth and to other spectroscopic analysis fields.

Two New Eremophilenolides from Ligularia muliensis

Two new eremophilenolides were isolated from the roots of Ligularia muliensis. Their structures were elucidated on the basis of the spectroscopic analysis as 6β-acetoxy-8β-hydroxyleremophil-7（11）-en- 12,8α-olide 1 and 6α-hydroxy-8βH-eremophil-7（11）-en- 12,Sa-olide 2.

Simultaneous Determination of Pt and Pd by First-and Second-Derivative Spectrometry

This paper has selected the amino-carboxylic complexing agent EDTA and KCl as the competing ligands of palladium and platinum. Their first-and second-derivative spectra with the zero-point method have been simultaneously determined. This method is simple and rapid, and moderate turbidity does not affect the determination.