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BACKGROUND American tegumentary leishmaniasis (ATL) is an endemic neglected tropical disease (NTD), its conventional treatment is toxic, slow, and invasive. Rapid diagnosis is crucial for the clinical management of suspected patients, so the development and use of low-cost, miniaturised and portable devices could be the key. OBJECTIVES This work aimed to develop a simple paper-based electrochemical platform for the serological detection of ATL. METHODS Platform was fabricated in Whatman N°1 paper, contains a hydrophobic zone generated by wax printing, two pencil graphite electrodes, and uses specific crude extracts (CA) antigens for ATL immuno-determination. The platform performance was analysed by measuring the relative impedance change for different antigen-antibody combinations. Then, 10 serum human samples previously diagnosed by the gold standard (five positive ATL cases and five non-ATL cases) were evaluated. FINDINGS The platform presented a linear response for the charge transfer resistance (ΔRct) and the interface reactance (ΔXc). Also, optimal working conditions were established (1/60 serum dilution and 180 µg/mL CA concentration). Then, the platform permits to distinguish between ATL and non-ATL (p < 0.05) human serum samples. MAIN CONCLUSIONS Our platform could allow the diagnosis, management, and monitoring of leishmaniasis while being an extremely simple and environmentally friendly technology.
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OBJECTIVES@#To establish a diatom database by analyzing the quatity, species distribution and differences of diatom in water samples of the whole navigable sections of the Beijing-Hangzhou Grand Canal, to provide a reference for the inference of the drowning site.@*METHODS@#Water samples were collected at 22 sites in the navigable sections of the Beijing-Hangzhou Grand Canal (Jining section to Yangzhou Section), and the diatoms at each site were qualitatively and quantitatively analyzed by using graphite digestion-scanning electron microscopy.@*RESULTS@#Sampling site T (Laohuaijiang River Line, Gaoyou City, Yangzhou City, Jiangsu Province) had the highest number of diatoms, while sampling site O (Siyang County, Suqian City, Jiangsu Province) had the lowest number of diatoms, with a large gap of 68 times. At sampling site Q (Jiangpu District, Huaian city, Jiangsu Province), there were 19 species of diatoms. The sampling site O had the least diatoms, with 7 species. There were no significant differences in species evenness and species diversity at each sampling site (P>0.05). Some sampling sites have characterized diatoms, such as Caloneis at station A (Taibai Lake, Weishan County, Shandong Province), Rhoicosphenia at station B (Nanyang Town, Weishan County, Shandong Province), Amphora at station I (Taierzhuang District, Zaozhuang City, Shandong Province) and Epithemia at station J (Pizhou 310 national highway, Xuzhou City, Jiangsu Province).@*CONCLUSIONS@#The species richness of diatoms gradually increased from north to south. Diatom species richness and species diversity might be higher in areas with complex environments and large population flow. Climate type has a certain influence on the distribution of diatoms.
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Humans , Beijing , Diatoms , Drowning , Rivers , WaterABSTRACT
Objective:To study the correction factor of the chamber wall of the reference air kerma rate reference ionization chamber (NIM-Ir-SG-100 type) for 192Ir radioactive source. Methods:The photon spectrum and ionization chamber wall correction factor of the radioactive source housing and irradiator model are calculated by Monte Carlo code. And then the photon energy, wall thickness and ionization chamber diameter, which affect the result of the chamber wall correction factor, are simulated.Results:After calculation, the simulation result of the correction factor of spherical graphite cavity ionization chamber wall was 1.037 7. Controlling a single variable, photon energy (0.3-1.3 MeV), wall thickness (0.2-0.5 cm), inner diameter (0.5 -15 cm), the maximum deviations of wall correction result were 1.62%, 3.30% and 2.86%, respectively.Conclusions:The self-made spherical graphite cavity ionization chamber has good performance, and the corrected kwall value of the chamber wall is within a reasonable range. The completion of the chamber wall correction factor is an important step to measure the reference air kerma rate of the 192Ir radioactive source and establish the measurement benchmark.
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The biocompatibility of nanomaterials has attracted much attention. Graphene oxide (GO) is a nanomaterial widely used in biomedicine, but its toxicity can not be ignored. In this study, the effect of GO on the blood system (the hemolysis rate, the fragility of erythrocyte, and acetylcholinesterase activity) was systematically investigated. The results showed that the hemolysis rate of erythrocytes was lower than 8% when the GO concentration was below 100 μg/mL (P5 μm (LGO) increased the activity of acetylcholinesterase by 42.67% (P<0.05). Then molecular dynamics simulation was used to study how GO interacted with acetylcholinesterase and increased its activity. The results showed that GO was attached to the cell membrane, thus may provide an electronegative environment that helps the hydrolysate to detach from the active sites more quickly so as to enhance the activity of acetylcholinesterase.
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Acetylcholinesterase , Erythrocytes , Graphite , NanostructuresABSTRACT
RESUMEN Se presenta el caso de una paciente femenina, de 15 años de edad, cuyo motivo de consulta fue la sensación de cuerpo extraño y aumento de volumen de coloración oscura en el globo ocular derecho. Antecedentes personales de trauma no referidos. Al examen físico se encontró una masa alargada, oscura, de bordes regulares y dura a la palpación, por debajo de la conjuntiva bulbar. Se realizó tratamiento quirúrgico y se extrajo un cuerpo extraño subconjuntival compatible con la punta de un lápiz, englobado en su extremo distal por un tejido fibrovascular, oscuro y con brillo metálico. Se exponen algunas consideraciones que pudieran ser la explicación para el comportamiento tisular adyacente al cuerpo extraño. Por lo poco común del caso se decidió su presentación.
ABSTRACT The case of a 15-year-old female patient is presented, whose main complaint was the sensation of a foreign body and increased volume of dark coloration in the right eyeball. Personal history of trauma not reported. On physical examination, an elongated, dark mass with regular edges and hard on palpation was found below the bulbar conjunctiva. Surgical treatment was performed and a subconjunctival foreign body compatible with the tip of a pencil was removed, encompassed at its distal end by a dark, fibrovascular tissue with metallic luster. Some considerations that could be the explanation for the tissue behavior adjacent to the foreign body are exposed. Due to its unusual nature, the presentation of the case was decided.
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Humans , Female , Adolescent , Eye Foreign Bodies/surgery , Eye Foreign Bodies/diagnosisABSTRACT
Piroxicam (PRX) was determined in pharmaceutical capsules with differential pulse voltammetry (DPV) in a three electrode system consisting of a pencil graphite electrode (PGE) as working electrode, a Pt wire and a reference electrode of Ag/AgCl/KCl 3 M. An irreversible oxidation peak was observed in Epa c.a. 0.6 V, which correlates to the oxidation of PRX. The coefficient of linear correlation obtained was 0.9946, with limit of detection of 2.1 µM and limit of quantification of 4.7 µM. PGE assays showed good analytical performance compared to high performance liquid chromatography and spectrophotometry, showing the potential to be further developed and employed in quick and simple analyses.
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Objective@#A label-free electrochemical immunosensor was developed for the detection of nuclear matrix protein-22 (NMP22) as a biomarker of bladder cancer.@*Methods@#The study was based on the establishment and validation of the methodology. Urine samples were collected from 20 patients with bladder cancer and 20 controls in the affiliated Hongqi hospital of Mudanjiang medical university from September in 2017 to July in 2019 to validate the developed method. A screen-printed electrode (SPE) was modified with a film of a composite made from the reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) immobilized Zn-based-Metal-organic frameworks deposited with Au nanoparticles (rGO-TEPA@Au-ZIF8). Primary antibody against NMP22 was immobilized on the Au nanoparticles on the surface of the modified SPE, which then was blocked with bovine serum albumin to elimiate nonspecific binding sites. The process of the construction of the proposed sensorwas characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Differential pulse voltammetry was used to evaluate the linear range, recovery, precision, selectivity and stability. The data were analyzed by Mann-Whitney U test.@*Results@#Under optimal conditions, the immunosensor exhibited a linear range of 0.01-1000 ng/mlwith a detection limit of 3.33 pg/ml (S/N=3) and a standard recovery of 97.65%-107.05%. The levels of NMP22 in urine samples from patients with bladder cancer [66.03 (4.34, 91.74)]ng/ml determined by the proposed sensor were significantly higher than those of controls 0.54(0.06, 8.84) ng/ml(P=0.001).@*Conclusion@#The immunosensor can achieve sensitive, rapid and acucurate detection of NMP22, and has potential application prospects in monitoring tumor markers.
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Objective A label-free electrochemical immunosensor was developed for the detection of nuclear matrix protein-22 (NMP22) as a biomarker of bladder cancer. Methods The study was based on the establishment and validation of the methodology. Urine samples were collected from 20 patients with bladder cancer and 20 controls in the affiliated Hongqi hospital of Mudanjiang medical university from September in 2017 to July in 2019 to validate the developed method. A screen-printed electrode (SPE) was modified with a film of a composite made from the reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) immobilized Zn-based-Metal-organic frameworks deposited with Au nanoparticles (rGO-TEPA@Au-ZIF8). Primary antibody against NMP22 was immobilized on the Au nanoparticles on the surface of the modified SPE, which then was blocked with bovine serum albumin to elimiate nonspecific binding sites. The process of the construction of the proposed sensorwas characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Differential pulse voltammetry was used to evaluate the linear range, recovery, precision, selectivity and stability. The data were analyzed by Mann-Whitney U test. Results Under optimal conditions, the immunosensor exhibited a linear range of 0.01-1000 ng/mlwith a detection limit of 3.33 pg/ml (S/N=3) and a standard recovery of 97.65％-107.05％. The levels of NMP22 in urine samples from patients with bladder cancer [66.03 (4.34, 91.74)]ng/ml determined by the proposed sensor were significantly higher than those of controls 0.54(0.06, 8.84) ng/ml(P=0.001). Conclusion The immunosensor can achieve sensitive, rapid and acucurate detection of NMP22, and has potential application prospects in monitoring tumor markers.
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Abstract Carbon nanostructures, obtained by underwater arc discharge of graphite electrodes, were studied by X-Ray Photoelectron Spectroscopy (XPS). It was observed that the spectra of the samples taken from the floating part of the synthesis products, composed basically by Carbon nano-onions (CNO), present differences with those obtained from the precipitate, which contains a mixture of CNOs and multi-walled Carbon Nanotubes (MWCNT). These differences are related with the presence of atoms of carbon located in orbitals with different degree of hybridization (sp2-sp3), which in turn is related to the diverse grade of curvature of the planes of carbon in the nanostructures present in the samples. The obtained results indicate that XPS can be an important element in the characterization of the products obtained by the above-mentioned method of synthesis.
Resumen Se utilizó la Espectroscopia Fotoelectrónica de Rayos X (XPS) para estudiar nanoestructuras de carbono obtenidas por descarga de arco de electrodos de grafito sumergidos en agua. Se observó que los espectros de las muestras tomadas de la fracción flotante de los productos de la síntesis, compuestas básicamente por nano-cebollas de carbono (CNO), presentan diferencias con los de las muestras obtenidas del precipitado, que contiene una mezcla de CNOs y nano-tubos de carbono de capas múltiples (MWCNT). Estas diferencias están asociadas con la presencia de átomos de carbono localizados en orbitales con diferente grado de hibridación (sp2-sp3), lo que a su vez se relaciona con las diferentes curvaturas de los planos de carbono en las nanoestructuras presentes en la muestras. Los resultados obtenidos indican que XPS puede ser un elemento importante en la caracterización de los productos obtenidos por el citado método de síntesis.
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A new derivative of ordered mesoporous carbon (GSH-CMK-3) has been prepared by chemical modification and functionalization of ordered mesoporous carbon with glutathione. The composite was fully characterized by means of Fourier transforming infrared spectroscopy (FT-IR), scanning electron microscope (SEM) image and thermogravimetric analysis (TGA). GSH-CMK-3 showed favorable chemical stability, thermal stability and excellent adsorption performance toward Cd2+and a maximum adsorption capacity of 87.87 mg/g was achieved. The adsorption kinetic follows pseudo-second-order adsorption model. In a sequential injection mini-column separation system, 0. 006 mol/L sulfourea (in 0. 2 mol/L HNO3) was adopted as eluent and the elution efficiency was 96%. With a sample volume of 1000 μL and 50 μL of eluate, an enrichment factor of 17.3 was obtained. A procedure for on-line selective separation and preconcentration of trace Cd2+was developed by graphite furnace atomic absorption spectrometry. Along with a detection limit of 1.9 ng/L (n=7,3σ) and a linear range of 0.05-0.20 μg/L, a RSD of 2.9% (n=13,100 ng/L) was achieved. The method was validated by analyzing Cd2+in a certified reference material GBW08608.
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Abstract: Pencil core granulomas are still infrequently reported in the literature. A 67-year-old woman presented with a 4mm hard blue subcutaneous nodule on the forehead. She remembered being injured with a pencil tip about 60 years before. The subcutaneous nodule was excised, which microscopically revealed a foreign body reaction with histiocytes containing fragmented coarse black particles. We diagnosed pencil-core granuloma based on the patient's history of pencil tip injury and histological examination findings.
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Humans , Female , Aged , Skin Diseases/pathology , Wounds, Penetrating/complications , Granuloma, Foreign-Body/pathology , Skin Diseases/complications , Granuloma, Foreign-Body/etiology , GraphiteABSTRACT
Objective To establish and evaluate a method for determination of total arsenic in urine by test-tube rapid digestion hydride generation atomic fluorescence spectrometry.Methods After digestion of urine samples using graduated test-tube and graphite digestion apparatus,arsenic content in urine was determined with atomic fluorescence spectrometer.Then the test results were evaluated by using quality control measures,such as precision and accuracy experiments,and the results between different laboratories were reviewed and compared.Results The urinary arsenic was in a linear range of 0-0.300 mg/L,correlation coefficient (r) ＞ 0.999 3,detection limit was 0.000 21 mg/L,relative standard deviation (RSD) ≤4.62％ and the recoveries of standard addition were 93.9％-104.3％.The value of standard reference material measured was within the allowable range.The blind sample of the national urinary arsenic was qualified.Conclusions This method is suitable for large scale determination of urinary arsenic for its micro sample amount needed,less interference and strong practicability.The error results are in a controlled range.
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OBJECTIVE: To establish a method for determining arsenic (As) and antimony (Sb) released from pharmaceutical glass packing materials to provide reference for improving the existing quality standard. METHODS: The samples were filled with 4% acetic acid to leach As and Sb. The extracting temperature was 98℃, and the extracting time was 2 h. Graphite furnace atomic absorption spectrometry (GFAAS) was used for the determination. RESULTS: As and Sb showed good linear relationship in a certain concentration range with linear correlation coefficients of 0.999 9 and 0.999 5. The recovery rates were 94.7%-106.9% and 100.0%-106.3%. The relative standard deviations of precision were 2.3% and 2.9%. The relative standard deviations of repeatability were 6.5% and 6.9%. The limits of detection were 1.67 and 2.54 ng·mL-1, respectively. The elements were nearly not detected in 16 batches of samples. CONCLUSION: The method is efficient and accurate and can be used for determination of As and Sb released from pharmaceutical glass packing materials, which brings supplementary contents to the existing quality standard.
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OBJECTIVE:To provide reference for improving the quality of Gelatin hollow capsule. METHODS:Atomic fluo-rescence spectrometry was used to determine the contents of Hg,As in Gelatin hollow capsule;graphite furnace atomic absorption spectrometry was used to determine the contents of Cr,Pb,Cd;flame atomic absorption spectrometry was used to determine the contents of Cu,Zn;and the contents of 7 elements in 48 batches of commercially available Gelatin hollow capsule were deter-mined. RESULTS:Each element showed good linear relationship in each mass concentration range(Cr,Pb,Cd,As and Hg were respectively 0-10,0-20,0-1.5,0-10,0-1.0μg/L;Cu and Zn were 0-1.8 mg/L)(r≥0.9969). The detection limits of Cr,Pb,Cd, Cu,Zn,Hg and As were 0.065,0.007,0.011,0.004,0.010,0.108,0.004 μg/L,respectively. RSDs of precision tests were no more than 2.5%(n=6);RSDs of reproducibility tests were no more than 7.5%(n=6);average recoveries ranged in 88.6%-109.5%(RSD≤6.7%,n=6). The contents of 7 elements in the 48 batches of samples were in line with the relevant provi-sions in Chinese Pharmacopoeia(2015 edition,part 4)and pharmacopoeia or standards in other countries or organizations. CON-CLUSIONS:The method shows high sensitivity,high precision with accurate and reliable results,and can be used for the content determination of Cr,Pb,Cd,Cu,Zn,Hg and As in Gelatin hollow capsule. The 48 batches of Gelatin hollow capsule from differ-ent manufacturers have good quality.
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OBJECTIVE:To provide reference for improving the quality of Gelatin hollow capsule. METHODS:Atomic fluo-rescence spectrometry was used to determine the contents of Hg,As in Gelatin hollow capsule;graphite furnace atomic absorption spectrometry was used to determine the contents of Cr,Pb,Cd;flame atomic absorption spectrometry was used to determine the contents of Cu,Zn;and the contents of 7 elements in 48 batches of commercially available Gelatin hollow capsule were deter-mined. RESULTS:Each element showed good linear relationship in each mass concentration range(Cr,Pb,Cd,As and Hg were respectively 0-10,0-20,0-1.5,0-10,0-1.0μg/L;Cu and Zn were 0-1.8 mg/L)(r≥0.9969). The detection limits of Cr,Pb,Cd, Cu,Zn,Hg and As were 0.065,0.007,0.011,0.004,0.010,0.108,0.004 μg/L,respectively. RSDs of precision tests were no more than 2.5%(n=6);RSDs of reproducibility tests were no more than 7.5%(n=6);average recoveries ranged in 88.6%-109.5%(RSD≤6.7%,n=6). The contents of 7 elements in the 48 batches of samples were in line with the relevant provi-sions in Chinese Pharmacopoeia(2015 edition,part 4)and pharmacopoeia or standards in other countries or organizations. CON-CLUSIONS:The method shows high sensitivity,high precision with accurate and reliable results,and can be used for the content determination of Cr,Pb,Cd,Cu,Zn,Hg and As in Gelatin hollow capsule. The 48 batches of Gelatin hollow capsule from differ-ent manufacturers have good quality.
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Objective To investigate the lead and cadmium contents in different sampling sites from full term neonatal placenta and to explore the role of placental sample in the evaluation of intrauterine heavy metals exposure.Methods The placentas from 30 healthy full term neonates were collected from the West China Second Hospital of Sichuan University during May and June 2016.Each placenta fetal side was divided into the left and right parts with the umbilical vein in the umbilical cord cross-section as the 12 o'clock direction.The villus lobular tissue samples were taken from the 1/4 radius in left part (site A) and 3/4 radius in the right part (site B).The graphite furnace atomic absorption spectrometry was used to detect the lead and cadmium contents in the samples.The elements contents in the site A and B were performed the paired t-test and correlation analysis.Results The mean contents of lead and cadmium in dry weight sample at placental site A were 91.8 and 66.7μg/kg which at the site B were 88.9 and 64.8 μg/kg respectively.The lead and cadmium contents at these two sites presented the positive correlation,the coefficients were 0.98 and 0.97 respectively,whereas the difference in contents between the tissues from different placental sites had no statistical significance.Conclusion The lead and cadmium contents of villus lobular tissue in the central part of placenta fetal side (1/4-3/4 radius area) are basically consistent,which is a reliable indicator for evaluating the intrauterine heavy metals exposure.
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OBJECTIVE: To establish a methodology to dilute blood sample with compound matrix modifier,and to determine the blood level of nickel using improved graphite furnace atomic absorption spectrometry( GFAAS). METHODS: The blood samples( 100. 00 μL) were diluted 5 times in 0. 12 g / L mass concentration of palladium chloride combined with 1. 00 %(V /V) Triton X-100 and 0. 10%(V /V) nitric acid,and the blood level of nickel was detected by GFAAS. RESULTS: The good linearity range of nickel mass concentration in blood was 0. 30-25. 00 μg / L,the correlation coefficient was 0. 999 7,the detection limit was 0. 30 μg / L,the minimum detectable mass concentration was 1. 50 μg / L,the recovery rate was99. 00 %-102. 75 %. The within-run and between-run relative standard deviations were 1. 43 %-3. 70 % and 2. 20 %-5. 03 %,respectively. Blood samples can be stored for at least 7 days at 4 ℃. CONCLUSION: This method is simple for operation,with high accuracy and precision,which is suitable for determination of nickel in blood in normal individuals and workers with occupational exposed to nickel.
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OBJECTIVE: To establish a method for determination of urinary tin by atomic fluorescence spectrophotometry.METHODS: The graphite digestion instrument was used to digest 2. 50 m L urinary sample with 1. 50 m L concentrated nitric acid,hydrochloric acid( volume fraction 4. 00%) was added to a total constant volume of 10. 00 m L. After 2. 50 m L of thiocarbamide-ascorbic acid( mass concentration 100 g / L) was added,hydrochloric acid( volume fraction 4. 00%) was added to a total constant volume of 25. 00 m L( equivalent to urinary sample was diluted 10 times),1. 00 m L of the sample was collected and detected by atomic fluorescence spectrophotometry. RESULTS: The good linear relationship was shown in the range of 4. 00-200. 00 μg / L with a correlation coefficient of 0. 999 5. The limit of detection was 0. 20 μg / L. The recovery rates ranged from 100. 20% to 100. 84%. The within-run relative standard deviation( RSD) and between-run RSD were 0. 11%-2. 01% and 1. 37%-5. 58%,respectively. The samples can be stored for 7 days under the temperature of4 ℃. CONCLUSION: This method has the advantages of high sensitivity,precision and convenient operation,which is suitable for the daily determination of urinary tin in human.
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OBJECTIVE:To establish a method for the contents determination of microelements in Chrysanthemum indicum from different production fields. METHODS:Graphite furnace atomic absorption (GFAAS) was used to determine the contents of Pb,Cd and As;HGAAS was used to determination the content of Hg;and FAAS was used to determine the contents of Cu,Fe, Mn,Ca,Mg and Zn. RESULTS:The linear range was 0-50 μg/L for Pb(r=0.999 9),0-10 μg/L for Cd(r=0.999 2),0-50 μg/L for As(r=0.999 0),0-20 μg/L for Hg(r=0.999 5),0-5 μg/L for Cu(r=0.999 3),0-15 μg/L for Fe(r=0.999 8),0-2 μg/L for Mn (r=0.999 9),0-50 μg/L for Ca(r=1.000 0),0-20 μg/L for Mg(r=0.999 9)and 0-2 μg/L for Zn(r=0.999 8);RSDs of precision, stability and reroducibility tests were lower than 3%;recoveries were 94.25%~97.43%(RSD=1.07%)、94.97%~99.46%(RSD=1.68%)、96.25%~99.46%(RSD=1.09%,n=6)、96.61%~99.91%(RSD=1.26%,n=6)、94.11%~98.41%(RSD=1.68%,n=6)、93.11%~99.59%(RSD=2.73%,n=6)、93.11%~99.48%(RSD=2.63%,n=6)、93.01%~99.85%(RSD=2.49%,n=6)、95.13%~99.75%(RSD=1.58%,n=6)、94.08%~97.37%(RSD=1.18%,n=6),respectively. CONCLUSIONS:The method is simple,stable and reproducible,and can be used for the contents determination of microelements in C. indicum from different pro-duction fields.