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1.
World J Diabetes ; 14(7): 1112-1125, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37547590

RESUMO

BACKGROUND: Commonly used glucocorticoids replacement regimens in patients with hypopituitarism have difficulty mimicking physiological cortisol rhythms and are usually accompanied by risks of over-treatment, with adverse effects on glucose metabolism. Disorders associated with glucose metabolism are established risk factors of cardiovascular events, one of the life-threatening ramifications. AIM: To investigate the glycometabolism profile in patients with hypopituitarism receiving prednisone (Pred) replacement, and to clarify the impacts of different Pred doses on glycometabolism and consequent adverse cardiovascular outcomes. METHODS: Twenty patients with hypopituitarism receiving Pred replacement [patient group (PG)] and 20 normal controls (NCs) were recruited. A flash glucose monitoring system was used to record continuous glucose levels during the day, which provided information on glucose-target-rate, glucose variability (GV), period glucose level, and hypoglycemia occurrence at certain periods. Islet ß-cell function was also assessed. Based on the administered Pred dose per day, the PG was then regrouped into Pred > 5 mg/d and Pred ≤ 5 mg/d subgroups. Comparative analysis was carried out between the PG and NCs. RESULTS: Significantly altered glucose metabolism profiles were identified in the PG. This includes significant reductions in glucose-target-rate and nocturnal glucose level, along with elevations in GV, hypoglycemia occurrence and postprandial glucose level, when compared with those in NCs. Subgroup analysis indicated more significant glucose metabolism impairment in the Pred > 5 mg/d group, including significantly decreased glucose-target-rate and nocturnal glucose level, along with increased GV, hypoglycemia occurrence, and postprandial glucose level. With regard to islet ß-cell function, PG showed significant difference in homeostasis model assessment (HOMA)-ß compared with that of NCs; a notable difference in HOMA-ß was identified in Pred > 5 mg/d group when compared with those of NCs; as for Pred ≤ 5 mg/d group, significant differences were found in HOMA-ß, and fasting glucose/insulin ratio when compared with NCs. CONCLUSION: Our results demonstrated that Pred replacement disrupted glycometabolic homeostasis in patients with hypopituitarism. A Pred dose of > 5 mg/d seemed to cause more adverse effects on glycometabolism than a dose of ≤ 5 mg/d. Comprehensive and accurate evaluation is necessary to consider a suitable Pred replacement regimen, wherein, flash glucose monitoring system is a kind of promising and reliable assessment device. The present data allows us to thoroughly examine our modern treatment standards, especially in difficult cases such as hormonal replacement mimicking delicate natural cycles, in conditions such as diabetes mellitus that are rapidly growing in worldwide prevalence.

2.
Front Chem ; 10: 841151, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35372278

RESUMO

A class of iodobenzoyldiazenido-functionalized POMs (TBA)3 [Mo6O18(=N=NCOAr)] (Ar = Ph-o-I (1); Ph-m-I (2); Ph-p-I (3); Ph-3,4-I2 (4); Ph-2,3,5-I3 (5) (TBA = tetrabutylammonium) were prepared via the refluxing reaction of α-octamolybdates, DCC, and corresponding hydrazides in dry acetonitrile. Their structures were determined by Fourier-transform infrared spectroscopy, ultraviolet-visible spectra, X-ray photoelectron spectroscopy, hydrogen-1 nuclear magnetic resonance, and high-resolution mass spectrometry. Research on the biological activity of title compounds shows that L3, L5, 3, and 5 demonstrate potent inhibitory activity against coxsackievirus B3 and low in vitro cytotoxic activity against Hep-2 cell lines. The covalent linkage between the iodobenzoyldiazenido components and POMs can enhance the molecular inhibitory efficiency of iodobenzohydrazides.

3.
World J Clin Cases ; 10(3): 1086-1092, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35127923

RESUMO

BACKGROUND: The corona virus disease 2019 (COVID-19) has been a pandemic for more than one year and estimated to affect the whole world in the near future. CASE SUMMARY: Here we reported that one COVID-19 patient with vesicles was treated by bullectomy. The patient's perioperative laboratory tests were analyzed. The pathological findings of bullectomy were described and compared with those of common bulla cases. CONCLUSION: This patient with vesicles underwent bullectomy and had a poor prognosis. He showed diffuse alveolar damage and extensive necrosis in bullectomy specimen. We hope our report will be of interest for clinicians who will treat COVID-19 patients in the future.

4.
Plant Sci ; 308: 110909, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34034866

RESUMO

Adventitious root (AR) formation is of great significance for apple rootstock breeding. It is widely accepted that miR393 influences AR formation in many plant species; however, the molecular mechanism by which factors regulate AR formation remains insufficient. In this study, the evolutionary relationship of mdm-miR393 and candidate target genes MdTIR1/AFB was systematically identified, and the expression patterns were analysed. Multisequence alignment analysis of miR393 family members suggests that miR393 conservatively evolved between different species. The evolutionary relationship of the TIR1/AFBs can be divided into G1, G2 and G3 subgroups. During AR formation, the expression level of mdm-miR393a/b/c was significantly upregulated at 1 d and 7 d by exogenous auxin treatment. Furthermore, the expression levels of MdTIR1A, MdTIR1D, MdAFB1, MdAFB2, MdAFB3, MdAFB4 and MdAFB8 also appeared to be significantly changed by exogenous auxin induction. Subsequently, tissue-specific expression analysis showed that the expression levels of mdm-miR393 and MdTIR1/AFBs in different tissues exhibited significant differences. The promoter of mdm-miR393 contains multiple elements that respond to ABA, adversity and light signals; auxin treatment can activate the mdm-MIR393b promoter but is obviously inhibited by NPA treatment. The targeting relationship between mdm-MIR393b and MdTIR1A was verified by expression patterns, degradation group data, transient tobacco conversion results, and genes functions experiments. Heterologous overexpression of mdm-MIR393b (35S::mdm-MIR393b) decreased the number of ARs in the phenotype and reduced the expression level of the target gene NtTIR1 in tobacco. Compared to the wild type, the 35S::mdm-MIR393b transgenic plants demonstrated insensitivity to auxin. Furthermore, tir1 mutant exhibited reduced root system structure relative to the control. The above results illustrated that mdm-MIR393b is involved in mediating AR formation by targeted regulation of MdTIR1A expression in apple rootstock.


Assuntos
Proteínas F-Box/genética , Ácidos Indolacéticos/metabolismo , Malus/genética , MicroRNAs/genética , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , RNA de Plantas/genética , Sequência de Bases , Proteínas F-Box/metabolismo , Malus/crescimento & desenvolvimento , MicroRNAs/metabolismo , Filogenia , Melhoramento Vegetal , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , RNA de Plantas/metabolismo , Alinhamento de Sequência
5.
Cell Physiol Biochem ; 42(1): 281-294, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28535513

RESUMO

BACKGROUND: Protein Kinase C-α (PKC-α) and epidermal growth factor receptor (EGFR) are both involved in diabetic kidney disease; however, the connection between these two proteins during high glucose-induced podocyte injury remains uncertain. METHODS: Diabetes was induced in SD rats by streptozotocin (STZ). Fourteen days later, the kidney cortex was removed and subjected to plasma membrane isolation and lipid raft fractionation. In vitro study human podocyte cell line was differentiated and subjected to various treatments. The levels of membranous protein and endocytosis were assessed by biotinylation and sodium 2-mercaptoethane sulfonate (MesNa) treatment. Gö6976 and PYR-41 were used as inhibitors of PKC-α and ubiquitin activating E1 enzyme, respectively. RESULTS: In diabetic rats, the abundance of PKC-α in the membranous fraction and the lipid raft domain is elevated, whereas the EGFR level is reduced. Consistently, in vitro high glucose treated podocytes, membranous EGFR is downregulated with increased PKC-α. Furthermore, the ubiquitination and endocytosis of EGFR are enhanced accompanied by extracellular signal-regulated kinase (ERK) signaling activation and podocyte damage during hyperglycemia. However, these processes can be ameliorated by inhibition of either PKC-α or ubiquitin activating E1 enzyme. CONCLUSION: During hyperglycemia, PKC-α mediates podocytic EGFR ubiquitination, endocytosis from cell surface and the subsequent ERK activation, which contributes to podocyte injury.


Assuntos
Endocitose/efeitos dos fármacos , Receptores ErbB/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glucose/farmacologia , Proteína Quinase C-alfa/metabolismo , Ubiquitinação/efeitos dos fármacos , Animais , Benzoatos/farmacologia , Linhagem Celular , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Regulação para Baixo/efeitos dos fármacos , Furanos/farmacologia , Humanos , Córtex Renal/metabolismo , Masculino , Fosforilação/efeitos dos fármacos , Podócitos/citologia , Podócitos/efeitos dos fármacos , Podócitos/metabolismo , Pirazóis/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Estreptozocina/toxicidade , Enzimas Ativadoras de Ubiquitina/antagonistas & inibidores , Enzimas Ativadoras de Ubiquitina/metabolismo
6.
Ying Yong Sheng Tai Xue Bao ; 27(1): 64-72, 2016 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-27228594

RESUMO

Field survey and laboratory experiment were conducted to study the soil anti-erodibility of abandoned croplands during different vegetation succession stages in hilly-gullied region of the Loess Plateau, based on the analysis of soil particle composition, size distribution and group characteristics, soil aggregate fractal dimensions and stability. The results showed that in the earlier stages of succession from annual to perennial herbs in abandoned croplands, soil size distribution changed a little bit, the fractal dimension of soil particle increased, soil structure improved, fractal dimension and damage percent of soil aggregate structure decreased, soil stability increased, thus soil anti-erodibility increased. Therefore, natural restoration of vegetation is of great significance to improve the soil structure, increase soil erosion resistance, reduce soil erosion and promote sustainable development of regional ecological environment.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Plantas , Solo , Fractais
7.
J Huazhong Univ Sci Technolog Med Sci ; 35(6): 834-841, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26670433

RESUMO

The type 1 insulin-like growth factor receptor (IGF-1R) and its downstream signaling components have been increasingly recognized to drive the development of malignancies, including non-small cell lung cancer (NSCLC). This study aimed to investigate the effects of IGF-1R and its inhibitor, AG1024, on the progression of lung cancer. Tissue microarray and immunohistochemistry were employed to detect the expressions of IGF-1 and IGF-1R in NSCLC tissues (n=198). Western blotting was used to determine the expressions of IGF-1 and phosphorylated IGF-1R (p-IGF-1R) in A549 human lung carcinoma cells, and MTT assay to measure cell proliferation. Additionally, the expressions of IGF-1, p-IGF-1R and IGF-1R in a mouse model of lung cancer were detected by Western blotting and real-time fluorescence quantitative polymerase chain reaction (FQ-PCR), respectively. The results showed that IGF-1 and IGF-1R were overexpressed in NSCLC tissues. The expression levels of IGF-1 and p-IGF-1R were significantly increased in A549 cells treated with IGF-1 as compared to those treated with IGF-1+AG1024 or untreated cells. In the presence of IGF-1, the proliferation of A549 cells was significantly increased. The progression of lung cancer in mice treated with IGF-1 was significantly increased as compared to the group treated with IGF-1+AG1024 or the control group, with the same trend mirrored in IGF-1/p-IGF-1R/IGF-1R at the protein and/or mRNA levels. It was concluded that IGF-1 and IGF inhibitor AG1024 promotes lung cancer progression.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/patologia , Modelos Animais de Doenças , Neoplasias Pulmonares/patologia , Receptor IGF Tipo 1/fisiologia , Tirfostinas/farmacologia , Adulto , Idoso , Animais , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Proliferação de Células , Progressão da Doença , Feminino , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Receptor IGF Tipo 1/antagonistas & inibidores
8.
Ying Yong Sheng Tai Xue Bao ; 26(2): 395-403, 2015 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-26094452

RESUMO

The objective of this study was to analyze the dynamic characteristics of seed rain on abandoned slopes in the hilly-gullied Loess Plateau region and identify the relationship between seed rain and standing vegetation. Three abandoned slopes were chosen as sampling sites in Zhifanggou watershed. Thirty traps were installed at each site to collect seed rain from October 2010 to April 2013. Standing vegetation was surveyed to identify dominant species in August 2011 and 2012, respectively. Thirty-seven species belonging to seventeen families were identified in the seed rain, and the dominant species, i.e., Lespedeza davurica, Astragalus scaberrimus, Setaria viridis, Cleistogenes squarrosa, Stipa bungeana, Bothriochloa ischcemum, Artemisia scoparia, A. gmelinii, and Heteropappus altaicus, took up to 95.8% of the total seed rain. Three species in seed rain were not found in the standing vegetation. The Sorensen similarity index between seed rain and standing vegetation was 0.77. Seed rain densities were 3737 and 6449 seeds · m(-2) in May 2011-April 2012 and May 2012-April 2013, respectively, and alternate bearing existed. During the study period, seed rain from different positions varied from 3853 to 37923 seeds · m(-2) and belonged to 7-15 species. The results indicated the space limitation of seed dispersal. Seed rain densities were in the middle of the pack compared with similar ecosystems in other studies. High temporal and spatial heterogeneity of seed rain was observed because of rainfall, microtopography and so on.


Assuntos
Biota , Dispersão de Sementes , Sementes , Artemisia , Astrágalo , China , Conservação dos Recursos Naturais , Ecossistema , Lespedeza , Poaceae , Setaria (Planta) , Solo
9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(8): 2039-42, 2013 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-24159841

RESUMO

To improve the quality of laser-induced breakdown spectroscopy, flat-mirror device was proposed. The effects of flat-mirror device on the radiation characteristics of laser-induced plasma were studied. The experimental results showed that when the device consisted of three flat-mirrors placed around the plasma, the spectral line intensity of Mg, Fe, Ba, Ti and Al increases by about 116.2%, 96.43%, 90.93%, 102.1% and 98.57% than that without flat-mirror device, and the signal-to-noise raises by around 39.17%, 32.48%, 38.07%, 39.95% and 21.30%,respectively. By measuring the plasma parameters, the mechanism of the radiation enhancement obtained with the device consisting of three flat-mirrors was explained. This method was an effective way to improve the detection capacity of LIBS.

10.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(1): 37-40, 2012 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-22497122

RESUMO

To improve the quality of laser-induced breakdown spectroscopy, nanosecond pulse laser generated by Nd : YAG laser was used to excite soil sample. The laser-induced plasma spectrum was observed using a grating spectrometer and a photoelectric detection system. The influence of laser output energy ranging from 100 to 500 mJ on the radiation intensity of plasma was studied. The results show that both the line intensity and signal-to-background ratio can be enhanced under the optimized condition that the laser energy is 200 mJ. The quality of spectrum was further improved after the laser beam used to excite the sample was defocused properly. When the defocusing position is + 6 mm, the spectral lines intensity of element Mg, Al, K and Fe increased about 46%, 63%, 59% and 45% compared to that without defocusing respectively. The spectral signal-to-background ratio increased about 11%, 31%, 35% and 38% respectively. This lays a foundation for detection of trace impurity element in soil.

11.
Acta Crystallogr C ; 67(Pt 4): m93-5, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21467616

RESUMO

The title compound, [Zn(2)(C(25)H(15)N(5)O(2))(2)]·2CH(2)Cl(2), is a dinuclear double-helical complex which lies on a crystallographic twofold axis. In the complex, both ligands are partitioned into two tridentate domains which allow each ligand to bridge both metal centres. Each Zn(II) atom is six-coordinated in a distorted octahedral environment formed by two amide N atoms, two quinoline N atoms and two pyridine N atoms from two different ligand molecules, with the central pyridine ring, unusually, bridging two Zn(II) atoms. The deprotonated ligand is not planar, the amide side chains being considerably twisted out from the plane of the central pyridine ring.


Assuntos
Compostos Organometálicos/química , Zinco/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Modelos Moleculares , Estrutura Molecular
12.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(10): 2601-5, 2010 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-21137381

RESUMO

In order to improve laser-induced breakdown spectroscopy for low-level elements testing capability, the enhancement effects of KCl additive on the emission spectra of soil samples were studied. The laser spectrum analytical system is composed of a high-energy neodymium glass laser ablating samples, a multifunctional and automatic scanning spectrometer, and a CCD data acquisition system recording plasma spectra. The electron temperature and electron density of plasmas were calculated by measuring spectral line intensity and stark broadening respectively. The experimental results showed that with the increase in the KCl additive, the spectral intensity, signal-to-background ratio, the electron temperature and the electron density all went up firstly and then down. When 15% KCl was added, the radiation intensity of plasma reached the maximum value, the spectral lines intensity of element Mn, Fe, and Ti increased by 2.23, 1.13 and 2.04 than that without additive respectively, the spectral signal-to-background ratio increased by 1.33, 0.89 and 0.94 times respectively; while the electron temperature and electron density of plasmas were heightened by 14% and 38% respectively.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(5): 1175-8, 2010 May.
Artigo em Chinês | MEDLINE | ID: mdl-20672595

RESUMO

In order to improve the radiation characteristic of laser-induced plasma, with the national standard soil taken as the target sample, a laser spectrum analytical system which composed of a high-energy neodymium glass laser, a multifunctional and compact integrated spectrometer, and a CCD detector was used to detect the influence of the NaCl sample additive on the laser plasma radiation intensity. The electron temperature and the electron density of the plasmas were also calculated from the lines intensity and stark broadening of emission spectral line respectively. The experimental results indicated that with the increase in the NaCl additive, the spectral intensity, signal-to-background ratio, the electron temperature, and the electron density all went up firstly and then down. When 15% NaCl was added, the radiation intensity of the plasma reached the maximum value, the spectral lines intensity of element Mn, K, Fe, and Ti increased by 39.2%, 42.5%, 53.9% and 33.8% compared to that without additive respectively, the spectral signal-to-background ratio increased by 64.4%, 84.39, 44.55% and 58.2% respectively, while the electron temperature and the electron density of the plasmas were heightened by 0.17 times and 0.36 times respectively.

14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 29(10): 2843-7, 2009 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-20038073

RESUMO

On the basis of consulting the home and abroad literatures in recent years, the research progress in the method of laser ablation solid sampling to the inductively coupled plasma source and its application in the analysis of material compositions are described. The present paper emphatically reviewed the influence of the laser-beam properties (output wavelength, pulse duration, repetition frequency, energy density) and atmosphere gases (helium and argon) on the sample ablation process, and discussed the functions of the laser ablation chamber, aerosol transmission pipelines, and sample introduction devices improved in the process of the evaporated material transferring to the inductively coupled plasma source. Getting small uniform aerosol particles and transporting the ablated materials to the inductively coupled plasma source efficiently and steadily are the key points to make laser ablation solid sampling technique more perfect, and the elements fractionation and evaporation deposition are important influence factors for the analysis performance. As a practical example, the application of laser ablation solid sampling inductively coupled plasma atomic emission spectrometry/mass spectrometry in the analysis of metal, glass, organic substance, and other samples was also discussed. The accuracy, precision, detection limits, and sensitivity of the analysis method were briefly reviewed.

15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(8): 1923-7, 2008 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-18975834

RESUMO

In the present paper, the physics property and nebulization character of the sample solution as well as elemental spectrum intensity were investigated with the prolonging of magnetization time after the water solution with the ethanol was magnetized under magnetic field of 0.24T. The magnetization mechanism was discussed. The experiment result shows that the efficient age-rate of the analyzed sample is increased. The peak values of the spectrum intensity appear when the ethanol is added into the sample. Under the magnetization time of 2 hours, the spectrum intensities of Zn, Pb, Cd, Fe, Si, Cu, Cr and Sr in the sample solution without the ethanol were increased by 22.9%, 38.8%, 25.6%, 48.3%, 52.4%, 6.0%, 22.3% and 22.7% than that with the non-magnetic water, respectively; The signal intensities of the elements in the sample solution with the ethanol of 6% were increased by 22.4%, 42.6%, 39.4%, 72.4%, 43.9%, 9.7%, 16.1% and 17.1% than that with the non-magnetic water, respectively. The detection limit of spectral analysis was reduced when the magnetized sample solution was analyzed.

16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(3): 656-62, 2008 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-18536436

RESUMO

In the present paper, the productions by applying laser-induced plasma spectral analysis technique in different research fields were summarized. Many examples of the application based on laser-induced breakdown spectroscopy (LIBS) and laser-induced plasma spectroscopy (LIPS) methods were introduced, including the substance composition and correlative characteristics of the solid samples (e.g. metal alloy, soil, concrete, mineral, fossil, medicine etc.), liquid samples (e.g. solution, pure water, liquid jets etc.), and gaseous samples (e.g. air, pure gas, vapor and aerosol etc.). Some other investigations and applications were also included. The factors, which influence the detection capability, were discussed. Laser wavelength, pulse energy, power density, environmental atmosphere, external electric field, carbon layer on sample surface, sample material characteristic, and so on all have effects on the precision and the limit of detection. Finally, a simple introduction of the improvements in experimental equipment and methods was also covered. The development of laser-induced plasma spectral analysis technique creates favorable conditions, such as convenience and shortcut, for many science and application researches. It plays an important role in the progress in science and technology.

17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(1): 183-7, 2008 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-18422148

RESUMO

In the present paper, the effects of the ethanol-water solution temperature (20, 40, and 60 degrees C) on the emission intensity of ICP source, plasma parameters (excitation temperature and electron density), physical properties (surface tension and viscosity) of sample solution, and nebulization (uptake rate, effective uptake rate and nebulization efficiency) were studied by using optical-to-electrical detection method. The experimental results showed that the velocity of the sample entering the plasma increased, so that the line intensity of the elements Zn, Fe, Mg, Si, and Sr in water increased obviously with increasing the content of ethanol and the rise of the corresponding solution temperature. And the excitation capacity in the plasma was strengthened with the rise of the ethanol-water solution temperature. The maximal spectrum intensity of the elements Zn, Fe, Mg, Si, and Sr at 60 degrees C was higher by 55.8%, 45.4%, 48.9%, 17.7%, and 21.6% than that at 20 degrees C, respectively. It's valuable for the detection of the trace element.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(6): 1047-50, 2007 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-17763753

RESUMO

Copper plasma was induced with a high energy neodymium glass laser(0-25J) beam ablating the Cu target in argon atmosphere. It was observed that the line intensity of the emission spectra increases when the ambient pressure(0.1-0.5 MPa) rises. In order to study the enhancement mechanism, with the model of local thermodynamic equilibrium, the electron temperature was measured in argon atmosphere. The experimental results showed that electron temperature increases as the pressure rises. In addition, spatially resolved electron temperature was measured in Ar atmosphere at 0.1, 0.3, 0.5 MPa.

19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 26(9): 1707-9, 2006 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-17112051

RESUMO

In an attempt to inhance the emission intensity of ICP, a conventional concentric pneumatic nebulizer was used with increased pressure, and the aqueous aerosol was partially let out to modulate the flow velocity of sample solution into the flame of the ICP. In the present work, the emission spectra of elements Ca, Si, Sr and Zn in water samples were measured, and the results showed that corresponding emission intensities are the highest at 0.05 MPa under the conventional condition, and after increasing the nebulizer gas pressure to 0.07 MPa and letting out part of aqueous aerosol, the peak values grew by 38%, 79%, 45% and 70%, respectively. In addition, the stability of the plasma radiation was not affected by the higher nebulizer gas pressure.

20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 26(5): 798-801, 2006 May.
Artigo em Chinês | MEDLINE | ID: mdl-16883839

RESUMO

In the present paper, the effects of argon atmosphere at high pressure (0. 2-1.1 MPa) on the radiation intensity of the plasma induced by a high energy neodymium glass laser (energy -30 J, pulse width 0.7 ms) were studied by recording the photograph and spectra of the plasma as well as measuring the ablated mass. The experimental results show that the volume of the plasma was compressed, the temperature increased, and the lightness enhanced significantly when pressure was raised. Under our experimental condition, the radiation intensities of the plasmas were enhanced with the increase in the gas pressure; but the ablated mass of the sample decreased. The measured results are discussed, combined with the process of the experiment.

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