Application of S-transform-based nonlinear processing for accurate LIBS quantitative analysis of iron ore slurry.

Real-time Fe content monitoring in iron ore slurry is crucial for evaluating concentrate quality and enhancing mineral processing efficiency. Laser-induced breakdown spectroscopy (LIBS) is a promising technique for the online monitoring of elemental content at industrial sites. However, LIBS measurements are hampered by the matrix effect and the self-absorption effect, limiting the precision of linear analytical processes. To overcome this, we propose to introduce a nonlinear processing unit based on the S-transform to incorporate nonlinearity into the data analysis process. This approach integrates a feature selection unit based on the spectral distance variable selection method (SDVS), a nonlinear processing unit based on the S-transform (ST), and a partial least squares regression model (PLS). To demonstrate the improvement in accuracy achieved through nonlinear processing, a comparative analysis involving five models, Raw-PLS, SDVS-PLS, ST-PLS, SDVS-ANN, and SDVS-ST-PLS, is conducted. The results reveal a significant improvement in the performance of the SDVS-ST-PLS model, effectively facilitating the successful application of the LIBSlurry analyzer to the mineral flotation process.

Efficacy and Safety of Tirofiban Before Stenting for Symptomatic Intracranial Atherosclerotic Stenosis: A Randomized Clinical Trial.

BACKGROUND AND OBJECTIVES: Acute stent thrombosis (AST) is not uncommon and even catastrophic during intracranial stenting angioplasty in patients with symptomatic high-grade intracranial atherosclerotic stenosis (ICAS). The purpose of this study was to investigate whether adjuvant intravenous tirofiban before stenting could reduce the risk of AST and periprocedural ischemic stroke in patients receiving stent angioplasty for symptomatic ICAS. METHODS: A prospective, multicenter, open-label, randomized clinical trial was conducted from September 9, 2020, to February 18, 2022, at 10 medical centers in China. Patients intended to receive stent angioplasty for symptomatic high-grade ICAS were enrolled and randomly assigned to receive intravenous tirofiban or not before stenting in a 1:1 ratio. The primary outcomes included the incidence of AST within 30 minutes after stenting, periprocedural new-onset ischemic stroke, and symptomatic intracranial hemorrhage. The outcomes were analyzed using logistic regression analysis to obtain an odds ratio and 95% confidence interval. RESULTS: A total of 200 participants (122 men [61.0%]; median [interquartile ranges] age, 57 [52-66] years) were included in the analysis, with 100 participants randomly assigned to the tirofiban group and 100 participants to the control (no tirofiban) group. The AST incidence was lower in the tirofiban group than that in the control group (4.0% vs 14.0%; adjusted odds ratio, 0.25; 95% CI 0.08-0.82; p = 0.02). No significant difference was observed in the incidence of periprocedural ischemic stroke (7.0% vs 8.0%; p = 0.98) or symptomatic intracranial hemorrhage between the 2 groups. DISCUSSION: This study suggests that adjuvant intravenous tirofiban before stenting could lower the risk of AST during stent angioplasty in patients with symptomatic high-grade ICAS. TRIAL REGISTRATION INFORMATION: URL: chictr.org.cn; Unique identifier: ChiCTR2000031935. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with symptomatic high-grade ICAS, pretreatment with tirofiban decreases the incidence of acute stent thrombosis. This study is Class II due to the unequal distribution of involved arteries between the 2 groups.

Efficient weakly supervised LIBS feature selection method in quantitative analysis of iron ore slurry.

On-stream analysis of the element content in ore slurry plays an important role in the control of the mineral flotation process. Therefore, our laboratory developed a LIBS-based slurry analyzer named LIBSlurry, which can monitor the iron content in slurries in real time. However, achieving high-precision quantitative analysis results of the slurries is challenging. In this paper, a weakly supervised feature selection method named spectral distance variable selection was proposed for the raw spectral data. This method utilizes the prior information that multiple spectra of the same slurry sample have the same reference concentration to assess the important weight of spectral features, and features selected by this prior can avoid over-fitting compared with a traditional wrapper method. The spectral data were collected on-stream of iron ore concentrate slurry samples during the mineral flotation process. The results show that the prediction accuracy is greatly improved compared with the full-spectrum input and other feature selection methods; the root mean square error of the prediction of iron content can be decreased to 0.75%, which helps to realize the successful application of the analyzer.

Adenovirus 7 Induces Interlukin-6 Expression in Human Airway Epithelial Cells via p38/NF-κB Signaling Pathway.

Human Adenovirus (AdV) infection is very common and usually has a significant impact on children. AdV-induced inflammation is believed to be one of the main causes of severe symptoms. However, an inflammatory response profile in the airway in AdV-infected children is still lacking, and the mechanism underlying AdV-induced inflammation in the airway is also poorly understood. In the current study, we determined the expression of a panel of inflammation cytokines in the airway samples from AdV 7 infected children and further investigated the molecular mechanism underlying AdV 7-induced cytokine expression. Our results showed that eight out of 13 tested inflammatory cytokines were significantly increased in nasal washes of AdV 7-infected children comparing to healthy control, with IL-6 showing the highest enhancement. AdV 7 infection of bronchial epithelial cell line and primary airway epithelial cells confirmed that AdV 7 increased IL-6 mRNA and protein expression in an infection dose-dependent manner. Promoter analysis revealed that AdV 7 infection transactivated IL-6 promoter and a NF-κB binding site in IL-6 promoter was involved in the transactivation. Further analysis showed that upon AdV 7 infection, NF-κB p65 was phosphorylated and translocated into nucleus and bound onto IL-6 promoter. Signaling pathway analysis revealed that p38/NF-κB pathway was involved in AdV 7 infection induced IL-6 elevation. Taken together, our study shows that AdV 7 infection triggers the expression of a range of inflammatory cytokines including IL-6 in the airway of infected children, and AdV 7 enhances IL-6 expression by transactivating IL-6 promoter via p38/NF-κB signaling pathway. Findings of our current study have provided more information toward a better understanding of AdV-induced airway inflammation, which might also benefit the development of intervention strategies.

Towards understanding global patterns of antimicrobial use and resistance in neonatal sepsis: insights from the NeoAMR network.

OBJECTIVE: To gain an understanding of the variation in available resources and clinical practices between neonatal units (NNUs) in the low-income and middle-income country (LMIC) setting to inform the design of an observational study on the burden of unit-level antimicrobial resistance (AMR). DESIGN: A web-based survey using a REDCap database was circulated to NNUs participating in the Neonatal AMR research network. The survey included questions about NNU funding structure, size, admission rates, access to supportive therapies, empirical antimicrobial guidelines and period prevalence of neonatal blood culture isolates and their resistance patterns. SETTING: 39 NNUs from 12 countries. PATIENTS: Any neonate admitted to one of the participating NNUs. INTERVENTIONS: This was an observational cohort study. RESULTS: The number of live births per unit ranged from 513 to 27 700 over the 12-month study period, with the number of neonatal cots ranging from 12 to 110. The proportion of preterm admissions <32 weeks ranged from 0% to 19%, and the majority of units (26/39, 66%) use Essential Medicines List 'Access' antimicrobials as their first-line treatment in neonatal sepsis. Cephalosporin resistance rates in Gram-negative isolates ranged from 26% to 84%, and carbapenem resistance rates ranged from 0% to 81%. Glycopeptide resistance rates among Gram-positive isolates ranged from 0% to 45%. CONCLUSION: AMR is already a significant issue in NNUs worldwide. The apparent burden of AMR in a given NNU in the LMIC setting can be influenced by a range of factors which will vary substantially between NNUs. These variations must be considered when designing interventions to improve neonatal mortality globally.

Phylogenetic and Epidemiological Analysis of Measles Viruses in Shenzhen, China from January 2015 to July 2019.

BACKGROUND Measles morbidity and mortality were significantly reduced after the measles vaccine was introduced in China in 1965. However, measles outbreaks easily occur in densely populated areas, especially where there is no universal vaccination. The outbreak that occurred in Shenzhen, the Chinese city with the largest internal immigration, provides a lesson in measles virus mutation and measles prevention. The present study is a phylogenetic analysis of measles viruses and comparison of clinical signs between individuals with and without vaccination. MATERIAL AND METHODS We performed phylogenetic analysis of the nucleoprotein (N) genes of measles virus from 129 measles patients in Shenzhen from January 2015 to July 2019. Phylogenetic trees were constructed using the neighbor-joining method. RESULTS The phylogenetic analysis showed all viruses were classified into genotype H1. In addition, there is often a seasonal measles outbreak in July each year. The clinical data showed that patients who were unvaccinated were more likely to have coughing, chronic bronchitis, conjunctivitis, catarrh, Koplik spots, and diarrhea. Children of migrant workers and those living in mountainous and rural districts accounted for most measles cases. CONCLUSIONS Our results showed there was a seasonal measles outbreak in Shenzhen Children's Hospital. All the measles virus from 129 measles patients were H1 viruses. The clinical signs also showed a difference between unvaccinated and vaccinated patients. Moreover, most of the unvaccinated patients came from migrant worker families. We suggest there is a need for increased health promotion and vaccination programs for migrant workers and people living in remote villages.

The Promising Effects of Transplanted Umbilical Cord Mesenchymal Stem Cells on the Treatment in Traumatic Brain Injury.

Many studies have reported the recovery ability of umbilical cord-derived mesenchymal stem cells (UC-MSCs) for neural diseases. In this study, the authors explored the roles of UC-MSCs to treat the traumatic brain injury. Umbilical cord-derived mesenchymal stem cells were isolated from healthy neonatal rat umbilical cord immediately after delivery. The traumatic brain injury (TBI) model was formed by the classical gravity method. The authors detected the behavior changes and measured the levels of inflammatory factors, such as interleukin-lß and tumor necrosis factor-α by enzyme linked immunosorbent assay (ELISA) at 1, 2, 3, 4 weeks after transplantation between TBI treated and untreated with UC-MSCs. Simultaneously, the expression of glial cell line-derived neurotrophic factor (GDNF) and brain derived neurotrophic factor (BDNF) were measured by real-time-polymerase chain reaction and ELISA.The authors found that the group of transplantation UC-MSCs has a significant improvement than other group treated by phosphate buffered saline. In the behavioral test, the Neurological Severity Scores of UC-MSCs + TBI group were lower than TBI group (P < 0.05), but not obviously higher than control group at 2, 3, and 4week, respectively. The inflammatory factors are significantly reduced comparison with TBI group (P < 0.05), but both GDNF and BDNF were higher than TBI group (P < 0.05). The results indicated that UC-MSCs might play an important role in TBI recovery through inhibiting the release of inflammatory factors and increasing the expression of GDNF and BDNF.

An Image Auxiliary Method for Quantitative Analysis of Laser-Induced Breakdown Spectroscopy.

Improving both the stability and accuracy of laser-induced breakdown spectroscopy (LIBS) is an issue in quantitative analysis. For certain environments outside of the laboratory, consistently and exactly maintaining the distance from the optical system to the sample surface is difficult, and fluctuations of this distance severely affect the stability of the spectrum. In this work, the principal components of the plasma images are extracted and used to correct the spectral line intensities as an auxiliary method to reduce spectral fluctuation. The presented image auxiliary method is combined with univariate analysis and multivariate analysis, and the element concentrations of Cu, Mn, V, and Cr in steel samples are analyzed. For univariate analysis, all the determination coefficients ( R2) of the four elements exceed 0.99, whereas the average relative standard deviations (RSDs) of the intensities decrease from 30.45, 23.14, 27.03, and 22.04%, to 2.13, 3.38, 2.49, and 3.58%, respectively. For the multivariate analysis, the R2 values for Cu, Mn, V, and Cr also all exceed 0.99, and the average RSDs of the predicted concentrations of the validation samples decrease to 2.87, 3.82, 2.86, and 6.51%, respectively.

Detection of K-ras gene mutations in feces by magnetic nanoprobe in patients with pancreatic cancer: A preliminary study.

The present study aimed to investigate the feasibility and effectiveness of detecting K-ras mutation by using magnetic nanoparticles in fecal samples of patients with pancreatic cancer at different stages. The novel methodology of K-ras mutation detection was compared to the existing methodology of cancer antigen (CA)19-9 examination. Patients with pancreatic cancer (n=88), pancreatic benign diseases who displayed chronic pancreatitis (n=35), pancreatic mucinous cyst neoplasms (n=10) and pancreatic serous cyst (n=9) admitted to the Department of Surgery, Jiaxing Second Hospital were enrolled in the present study. Fecal samples were collected from all patients, DNA was extracted and magnetic nanoprobe was then used to detect K-ras mutation. The results obtained using the novel magnetic nanoprobe detection technique showed a K-ras mutation rate of 81.8% (72/88) in the patients with pancreatic cancer and 18.5% (10/54) in patients with pancreatic benign diseases. In patients with pancreatic cancer, the K-ras mutation rate was comparable in stages I + IIA and IIB + III + IV (78.9 vs. 84.0%; P>0.05). The sensitivity and specificity of K-ras mutation for detection of pancreatic cancer was 81.8 and 81.5%, respectively. Sixty-eight pancreatic cancer patients had >37 U/ml CA99 with a sensitivity and specificity for pancreatic cancer detection of 77.3 and 77.8%, which was not significantly lower than detection by the fecal K-ras mutations (P>0.05). Combinational detection of fecal K-ras mutations and serum CA19-9 significantly increased the sensitivity regarding pancreatic cancer detection to 97.7% (P<0.05), while the specificity was not enhanced (80.9%; P>0.05) compared with fecal K-ras mutations or CA19-9 alone. The findings showed that the magnetic nanoprobe is able to detect fecal K-ras mutations in different stages of pancreatic cancer, with comparable sensitivity and specificity to CA19-9 examination for differentiating pancreatic cancer. Furthermore, combined detection of CA19-9 and K-ras mutations has enhanced sensitivity compared with CA19-9 alone.

Photo-controlled aptamers delivery by dual surface gold-magnetic nanoparticles for targeted cancer therapy.

Dual surfaced dumbbell-like gold magnetic nanoparticles (Au-Fe3O4) were synthesized for targeted aptamers delivery. Their unique biological properties were characterized as a smart photo-controlled drug carrier. DNA aptamers targeting vascular endothelial growth factor (VEGF) were assembled onto the surface of Au-Fe3O4 by electrostatic absorption. The binding capacity of the nanoparticles with VEGF aptamers was confirmed by gel electrophoresis. The targeted recognization of ovarian cancer cells by the aptamers-functionalized Au-Fe3O4 nanoparticles (Apt-Au-Fe3O4 NPs) was observed by confocal microscopy. Apt-Au-Fe3O4 was found to bind with SKOV-3 ovarian cancer cells specifically, leading to marked intracellular release of aptamers upon plasmon-resonant light (605nm) radiation, and to enhance the in vitro inhibition against tumor cell proliferation. The results show high potential of Apt-Au-Fe3O4as a targeted cancer hyperthermia carrier by remote control with high spatial/temporal resolution.

Roflumilast Reduces Cerebral Inflammation in a Rat Model of Experimental Subarachnoid Hemorrhage.

Roflumilast, a selective inhibitor for PDE4, is approved by FDA as an anti-inflammation drug for treatment of chronic obstructive pulmonary disease (COPD). This study investigates the effects of roflumilast on cerebral inflammation in the rat SAH model. Here, we show that subcutaneous administration of roflumilast (3 mg/kg) significantly improved the neurological deficits. Measurement of evans blue extravasation and brain water content revealed a significant reduction of blood-brain barrier permeability and brain edema. Importantly, roflumilast treatment remarkably decreased levels of IL-1ß, IL-6, and TNF-α and the number of apoptotic neurons in the brain after SAH. These results indicate that roflumilast is effective in treating cerebral inflammation following SAH.

Targeted chimera delivery to ovarian cancer cells by heterogeneous gold magnetic nanoparticle.

Efficient delivery of small interfering RNAs (siRNAs) to the targeted cells has remained a significant challenge in clinical applications. In the present study, we developed a novel aptamer-siRNA chimera delivery system mediated by cationic Au-Fe3O4 nanoparticles (NPs). The chimera constructed by VEGF RNA aptamer and Notch3 siRNA was bonded with heterogeneous Au-Fe3O4 nanoparticles by electrostatic interaction. The obtained complex exhibited much higher silencing efficiency against Notch3 gene compared with chimera alone and lipofectamine-siRNA complex, and improved the antitumor effects of the loaded chimera. Moreover, the efficient delivery of the chimera by Au-Fe3O4 NPs could reverse multi-drug resistance (MDR) of ovarian cancer cells against the chemotherapeutic drug cisplatin, indicating its potential capability for future targeted cancer therapy while overcoming MDR.

Identification of serum miRNAs differentially expressed in human epilepsy at seizure onset and post-seizure.

MicroRNAs (miRNAs) function as potential novel biomarkers for disease detection due to their marked stability in the blood and the characteristics of their expression profile in several diseases. In the present study, microarray­based serum miRNA profiling was performed on serum obtained from three patients with epilepsy at diagnosis and from three healthy individuals as controls. This was followed by reverse transcription­quantitative polymerase chain reaction analysis in a separate cohort of 35 health volunteers and 90 patients with epilepsy. The correlations between miRNAs and clinical parameters were analyzed. The array results showed that 15 miRNAs were overexpressed and 10 miRNAs were underexpressed (>2­fold) in the patients with epilepsy. In addition, four miRNAs, including miR­30a, miR­378, miR­106b and miR­15a were found to be overexpressed in the serum of patients at seizure onset, compared with post­seizure. When the patients were at seizure onset, the expression of miR­30a was positively associated with seizure frequency. No significant differences were found between miR­30a and gender, age or number of years following diagnosis. The expression levels of miR­378, miR­106b and mir­15a were not associated with the clinical parameters in the patients with seizures. Calcium/calmodulin­dependent protein kinase type IV was a target of miR­30a, and its expression was increased following seizure and was negatively correlated with miR­30a in the patients with epilepsy. The present study provided the first evidence, to the best of our knowledge, that the expression levels of miR­378, miR­30a, miR­106b and miR­15a were enhanced in epileptic patients with seizures. miR-30a may be useful for prognostic prediction in epilepsy.

Aptamer Functionalized Cisplatin-Albumin Nanoparticles for Targeted Delivery to Epidermal Growth Factor Receptor Positive Cervical Cancer.

Targeted nanocarriers may offer a new approach to improve the efficacy and tolerability of cisplatin, which are commonly used to treat cancers as a first line chemotherapy for most types of cancer. In the present study, we have developed EGFR-targeted albumin-cisplatin nanoparticles for tumor targeted delivery of cisplatin. The cisplatin NPs were conjugated with EGFR aptamer, which binded to Hela cells specifically, then taken up by tumor cells through receptor mediated endocytosis. The aptamers accumulate in the tumor and interact with the receptor on the surface of Hela cells, successfully blocked EGF-induced EGFR phosphorylation, exerting its targeting and therapy function. Here we demonstrate that the EGFR aptamer functioned NPs enhanced in vitro antitumor effects and markedly improved its tolerability and in vivo efficacy when compared with free cisplatin and other single treatment. Furthermore, the Apt-Pt NPs treatment resulted in reduced systemic and nephrotoxicity, validated by decreased biodistribution of platinum in the major organs as quantified by ICP-MS. The Apt-Pt NPs provides a remarkable improvement in the drug therapeutic efficacy and tolerability in vivo, and will be generalized as a principle for development of novel nanocarriers for targeted tumor therapy.

[In-Situ Analysis of Solid Steel Samples with Remote Double-Pulse Laser-Induced Breakdown Spectroscopy System].

In order to realize real-time, online monitoring of the component of steel and other metal smelting process, we designed a remote double-pulse laser-induced breakdown spectroscopy (LIBS) analysis system which can realize non-contact remote measurement and component analysis for long distance sample. The paper first tests the system on solid standard steel samples, which provides basis for online monitoring the component of molten steel. The experimental results show：laser focal spot is about 1mm in long distance; double-pulse ablation depth is deeper than single pulse's; the optimum delay of double-pulse is non-consistent in different distances; the enhancement effect of double- pulse in 3.1 m is better than that in 2.1 m，and the maximum enhancement is 5.19 of Ti(Ⅰ) 319.99 nm; the calibration curve of R2 is about 0.99, RSD being less than 5%, RMSE being less than 0.021%, LOD being less than 500 ppm for most elements in 2.1 m, which is better than that in 3.1 m.

Highly efficient Gab2 siRNA delivery to ovarian cancer cells mediated by chitosan-polyethyleneimine nanoparticles.

Malignant bowel obstruction (MBO) is a serious complication which causes high death rate and low quality of life (QOL) for patients diagnosed at an advanced stage of ovarian cancer. RNA interference (RNAi) could be a promising method for the treatment of ovarian cancer and could decrease the morbidity of MBO. Gab2 gene is overexpressed in ovarian cancer compared with normal ovarian tissue, and regulates the migratory behaviors and E-cadherin expression via activation of the PI3K pathway in ovarian cancer cells. Here, chitosan-polyethyleneimine (PEI, Mw 1800) copolymer nanoparticles were synthesized as nanocarriers to deliver Gab2 siRNA into SKOV3 cells. The silencing effects against the Gab2 gene and the antitumor effects by the chitosan-PEI-Gab2 siRNA nanoparticles (chitosan-PEI-Gab2 NPs) were studied. Results showed that highly efficient silencing effects against Gab2 expression and its downstream effector, AKT protein, at more than 90% deregulation were obtained by chitosan-PEI NP mediated Gab2 siRNA delivery, so as to exhibit obvious antitumor effects against SKOV3 cells with low cytotoxicity, and induce cell apoptosis in early and late stages. The study will provide novel strategies to overcome MBO in ovarian cancer by the efficient knockdown of Gab2 expression.

Osthole Upregulates BDNF to Enhance Adult Hippocampal Neurogenesis in APP/PS1 Transgenic Mice.

Adult hippocampal neurogenesis occurs in the dentate gyrus (DG) of the mouse hippocampus, and plays roles in learning and memory progresses. In amyloid precursor protein (APP)/presenilin 1 (PS1) transgenic mice, a rodent model of Alzheimer's disease (AD), severe impairment of neurogenesis in the dentate subgranular zone (SGZ) of the DG has been reported. Osthole, an active constituent of Cnidium monnieri (L.) CUSSON, has been reported to exert neuroprotective effects and may promote neural stem cell proliferation. However, whether osthole ameliorates spatial memory deficits and improves hippocampal neurogenesis in APP/PS1 mice remains unknown. In this study we found that osthole (30 mg/kg intraperitoneally (i.p.) once daily) treatment dramatically ameliorated the cognitive impairments by Morris Water Maze test and passive avoidance test, and augmented neurogenesis in the DG of hippocampus in APP/PS1 mice. Furthermore, osthole treatment upregulated expression of brain-derived neurotrophic factor (BDNF) and enhanced activation of the BDNF receptor tyrosine receptor kinase B (TrkB) following increased phosphorylation of cyclic AMP response element-binding protein (CREB), indicating that osthole improves neurogenesis via stimulating BDNF/TrkB/CREB signaling in APP/PS1 transgenic mice.

Effect of platelet-derived growth factor-B on renal cell carcinoma growth and progression.

BACKGROUND: Platelet-derived growth factor-B (PDGF-B) expression promotes the proliferation of mural cells surrounding the blood vessels during angiogenesis. The effect of PDGF-B involved in angiogenesis on tumor growth and progression in clear cell renal cell carcinoma (ccRCC) is unknown. METHODS: We examined the expression of PDGF-B and its receptor PDGFR-ß in 174 patients with ccRCC by microarray analysis. Cancer-specific survival was estimated using the Kaplan-Meier method. PDGF-B-transfected and mock-transfected ACHN cells were implanted into mice to induce tumor formation and tumor growth, respectively, and progression in mice models was assessed using immunohistochemistry and histomorphology. The role of PDGF-B during angiogenesis in vitro was evaluated by flow cytometry analysis, cell migration, and tube formation assay. RESULTS: High expression of PDGF-B was associated with significantly decreased risk of cancer-specific mortality (P ≤ 0.001). The data indicated significant inhibition of tumor growth (P ≤ 0.05) and a reduction in proliferating tumor cells (P = 0.019) in vivo. PDGF-B also inhibits tumor metastasis and invasion events in tumor-bearing mice models. In vitro studies revealed that the tube formation capability of vascular smooth muscle cells (VSMCs), which are believed to be the precursors to pericytes in vivo, significantly induced by PDGF-B. The PDGF-B overexpression also results in a tendency to reside in S and G2/M phases of the cell cycle (P = 0.001) and increasing migration capability of VSMCs (P ≤ 0.001). CONCLUSION: Our results demonstrated that PDGF-B, which increased VSMCs proliferation and migration capability during angiogenesis, limited tumor growth and progression in ccRCC. Therefore, PDGF-B may be a novel and promising prognostic marker.

[Quantitative analysis of alloy steel based on laser induced breakdown spectroscopy with partial least squares method].

In the present paper both the partial least squares (PLS) method and the calibration curve (CC) method are used to quantitatively analyze the laser induced breakdown spectroscopy data obtained from the standard alloy steel samples. Both the major and trace elements were quantitatively analyzed. By comparing the results of two different calibration methods some useful results were obtained: for major elements, the PLS method is better than the CC method in quantitative analysis; more importantly, for the trace elements, the CC method can not give the quantitative results due to the extremely weak characteristic spectral lines, but the PLS method still has a good ability of quantitative analysis. And the regression coefficient of PLS method is compared with the original spectral data with background interference to explain the advantage of the PLS method in the LIBS quantitative analysis. Results proved that the PLS method used in laser induced breakdown spectroscopy is suitable for quantitative analysis of trace elements such as C in the metallurgical industry.