Abstract Based on the inverse piezoelectric effect and other characteristics of piezoelectric ceramics, a new type of piezoelectric variable friction damper is developed, and the output performance test of piezoelectric ceramic actuator and piezoelectric variable friction damper is carried out, and the parametric mechanical model of the damper is established by using Simulink to carry out numerical simulation, and compared and analyzed with the test results. The results of the study show that the simulation and the test present a good regular agreement. With the increment of loading voltage, the displacement deformation and zero-displacement thrust of piezoelectric ceramic actuator are approximately linear with the loading voltage; when the loading voltage is increased by 15V every time, the test value of the output damping force of the damper increases by 259.66N on average step by step, and the simulated value increases by 256.14N step by step, and the damping force has a linearly incremental relationship with the voltage and the slope of the linear increase is 16.434.

SUMMARY: This study is to investigate the effect of home-based cardiac rehabilitation (HBCR) on quality of life, functional capacity, and readmission rates in patients with heart failure. Randomized controlled trials (RCTs) were screened from Cochrane Library, CINAHL, EMBASE, and MEDLINE. The intervention group received a standardized HBCR or a comprehensive rehabilitation strategy that included HBCR. The participants in the control group received CR at a medical center or usual care without CR intervention. The main outcome measurements included quality of life, exercise capacity, mortality and re-hospitalization. This meta-analysis included 20 RCTs, in which 16 studies compared HBCR with usual care, and 4 studies compared HBCR with center-based CR. In comparison with the usual care, HBCR improved the total quality of life score [MD=-5.85, 95 % CI (-9.76, - 1.94), P=0.003, I2=75 %]. Patients with HBCR and usual care were significantly different in VO2max [MD=1.05 mL/kg/min, 95 % CI (0.35, 1.75), P=0.003, I2=46 %]. However, VO2max of patients with HBCR was not significantly different from those with center-based CR [MD=0.08 mL/kg/min, 95 % CI (-1.29, 1.44), P=0.91, I2=0 %]. There was statistically significant difference in the 6-min Walk Distance between usual care and HBCR (for distance [MD=11.84, 95 % CI (7.41, 16.28), P<0.00001, I2=0 %]; and for feet [MD=98.93, 95 % CI (26.79, 171.08), P=0.007, I2=56 %]). However, there was no significant difference in 6-min Walk Distance between patients with HBCR and center-based CR [MD=12.45, 95 % CI (-9.81, 34.72), P=0.27, I2=0 %] , or in anxiety and depression between patients with usual care and HBCR (for anxiety, [MD=-0.25, 95 % CI (-0.56, 0.05), P=0.11, I2=0 %]; for depression, [MD=-0.18, 95 % CI (-0.51, 0.16), P=0.30, I2=0 %] . No significant difference was found in death number [RR=1.04, 95 % CI (0.55, 1.98), P=0.90, I2=0 %] or in the number of re-hospitalization [RR=0.88, 95 % CI (0.66, 1.18), P=0.40, I2=0 %] between usual care and HBCR. For patients with heart failure, compare with usual care and center-based CR, HBCR can improve the total quality of life. Compare with usual care, HBCR can improve VO2max and 6-min Walk Distance, but compare with center- based CR, there are no differences in mortality, re-hospitalization rate or incidence of anxiety and depression. Additionally, center- based CR and HBCR showed similar outcomes and medical costs.

RESUMEN: El objetivo de este estudio fue investigar el efecto de la rehabilitación cardíaca domiciliaria (HBCR) sobre la calidad de vida, la capacidad funcional y las tasas de reingreso en pacientes con insuficiencia cardíaca. Se seleccionaron ensayos controlados aleatorios (ECA) de la Biblioteca Cochrane, CINAHL, EMBASE y MEDLINE. El grupo de intervención recibió un HBCR estandarizado o una estrategia de rehabilitación integral que incluía HBCR. Los participantes del grupo de control recibieron RC en un centro médico o atención habitual sin intervención de RC. Las principales medidas de resultado incluyeron la calidad de vida, la capacidad de ejercicio, la mortalidad y la rehospitalización. Este metanálisis incluyó 20 ECA, en los que 16 estudios compararon HBCR con la atención habitual y 4 estudios compararon que mejoró la puntuación total de calidad de vida [DM=-5,85, IC del 95 % (-9,76, -1,94), P=0,003, I2=75 %]. Los pacientes con HBCR y atención habitual fueron significativamente diferentes en el VO2máx [DM = 1,05 ml/kg/ min, IC del 95 % (0,35, 1,75), P = 0,003, I2 = 46 %]. Sin embargo, el VO2max de los pacientes con HBCR no fue significativamente diferente de aquellos con CR basada en el centro [DM = 0,08 ml/kg/min, IC del 95 % (-1,29, 1,44), P = 0,91, I2 = 0 %]. Hubo una diferencia estadísticamente significativa en la distancia de caminata de 6 minutos entre la atención habitual y HBCR (para la distancia [DM=11,84, IC del 95 % (7,41, 16,28), P<0,00001, I2=0 %]; y para los pies [DM= 98,93, IC 95 % (26,79, 171,08), P=0,007, I2=56 %]). Sin embargo, no hubo una diferencia significativa en la distancia de caminata de 6 minutos entre los pacientes con HBCR y CR basada en el cen- tro [DM = 12,45, IC del 95 % (-9,81, 34,72), P = 0,27, I2 = 0 %], o en la ansiedad y depresión entre pacientes con atención habitual y HBCR (para ansiedad, [DM=-0,25, IC del 95 % (-0,56, 0,05), P=0,11, I2=0 %]; para depresión, [DM=-0,18, 95 % IC (- 0,51, 0,16), P=0,30, I2=0 %] No se encontraron diferencias significativas en el número de muertes [RR=1,04, IC del 95 % (0,55, 1,98), P=0,90, I2=0 %] o en el número de reingresos [RR=0,88, IC 95 % (0,66, 1,18), P=0,40, I2=0 %] entre atención habitual y HBCR. Para los pacientes con insuficiencia cardíaca, en comparación con la atención habitual y la CR en un centro, la HBCR puede mejorar la calidad de vida total. En comparación con la atención habitual, la HBCR puede mejorar el VO2máx y la distancia recorrida en 6 minutos, pero en comparación con la CR basada en un centro, no hay diferencias en la mortalidad, la tasa de rehospitalización o la incidencia de ansiedad y depresión. Además, CR y HBCR basados en el centro mostraron resultados y costos médicos similares.

Abstract Gallstones disease is classified as cholesterol, pigment and mixed gallstones. Pigment gallstones is a common disease, and some patients experienced complications such as biliary pain and cholecystitis. Defatted walnut powder extract (DWPE) is extracted from the main by-product after oil extraction of the functional food walnut and can treat cholesterol gallstones. However, the effect of DWPE on pigment gallstones has not been reported. Thus, this paper aimed at exploring the potential mechanism of alleviating pigment gallstones and the metabolism of DWPE in vitro by UPLC-Q-Exactive Orbitrap MS to elucidate potential pharmacodynamic substances. It was found that DWPE significantly reduced the incidence of gallstones, the contents of unconjugated bilirubin and calcium, the inflammation of gallbladder tissue, the edema and congestion of gallbladder tissue, and the infiltration of inflammatory cells. In metabolism, a total of 35 metabolites of DWPE, including its main compounds ellagic acid and glansreginin A, were characterized in the intestine with various metabolic reactions. Presumably, the small molecular compounds generated after the metabolism by intestinal bacteria may be the pharmacodynamic substances of DWPE on pigment gallstones. This study revealed the effect of DWPE in treating pigment gallstones and their metabolism in vitro.

Inadequate invasion and excessive apoptosis of trophoblast cells are associated with the development of preeclampsia. Vitamin D deficiency in pregnant women may lead to an increased risk of preeclampsia. However, the underlying mechanisms by which vitamin D is effective in preventing preeclampsia are not fully understood. The objectives of this study were to investigate the role of lysosome-associated membrane glycoprotein 3 (LAMP3) in the pathogenesis of preeclampsia and to evaluate whether vitamin D supplementation would protect against the development of preeclampsia by regulating LAMP3 expression. Firstly, the mRNA and protein levels of LAMP3 were significantly upregulated in the placentas of preeclampsia patients compared to normal placentas, especially in trophoblast cells (a key component of the human placenta). In the hypoxia/reoxygenation (H/R)-exposed HTR-8/Svneo trophoblast cells, LAMP3 expression was also upregulated. H/R exposure repressed cell viability and invasion and increased apoptosis of trophoblast cells. siRNA-mediated knockdown of LAMP3 increased cell viability and invasion and suppressed apoptosis of H/R-exposed trophoblast cells. We further found that 1,25(OH)2D3 (the hormonally active form of vitamin D) treatment reduced LAMP3 expression in H/R exposed trophoblast cells. In addition, 1,25(OH)2D3 treatment promoted cell viability and invasion and inhibited apoptosis of H/R-exposed trophoblast cells. Notably, overexpression of LAMP3 abrogated the protective effect of 1,25(OH)2D3 on H/R-exposed trophoblast cells. Collectively, we demonstrated trophoblast cytoprotection by vitamin D, a process mediated via LAMP3.

Abstract In order to obtain the extraction process of defatted walnut powder (DWP), an ultrasound-assisted extraction based on artificial neural network was established, and the activity of the extract was evaluated. The artificial neural network (ANN) was used to model different parameters, including the yield of extraction, the concentrations of glansreginin A and ellagic acid, and obtained the optimal extraction process: solvent to material ratio of 9.5 mL/g, ethanol concentration of 68%, extraction period of 55 min, and extraction three times. Then, the antioxidant scavenging ability of DWP obtained by ANN was compared with other extraction methods. The results showed that DWP extracted by artificial neural network demonstrated good activity in scavenging DPPH and ABTS radicals.

Abstract The objective of this study was to evaluate the fertilization capability of White Bengal Tiger frozen-thawed completely immotile spermatozoa after interspecific intracytoplasmic sperm injection (ICSI) with bovine oocytes. The fertilization status of presumptive zygotes was assessed 18 h after ICSI by immunofluorescence staining and confocal microscopy. The fertilization rate was 34.8% (8/23), as confirmed by the extrusion of two polar bodies, or male and female pronuclei formation. For unfertilized oocytes (65.2%, 15/23), one activated oocyte had an activated spermatozoon but most were unactivated oocytes with unactivated spermatozoa (1/15, 6.7% vs 10/15, 66.7%, respectively, p < 0.05). These results showed that White Bengal Tiger frozen-thawed completely immotile spermatozoa retained the capacity to fertilize bovine oocytes after interspecific ICSI. This is the first report of in vitro produced zygotes using tiger immotile sperm with bovine oocytes by interspecific ICSI technique, which provides an efficient and feasible method for preservation and utilization of endangered feline animals.

Resumo Justificativa e objetivos A administração pré‐operatória de Flurbiprofeno Axetil (FA) é amplamente usada para a modulação da analgesia. No entanto, a relação entre FA e fármacos sedativos permanece obscura. Neste estudo, nosso objetivo foi investigar os efeitos de diferentes doses de FA na Concentração Efetiva mediana (CE50) do propofol. Métodos Noventa e seis pacientes (ASA I ou II, com idades de 18–65 anos) foram alocados aleatoriamente em quatro grupos na proporção de 1:1:1:1. Dez minutos antes da indução, o Grupo A (grupo controle) recebeu 10 mL de Intralipid, enquanto os grupos B, C e D receberam FA na dose de 0,5 mg.kg‐1; 0,75 mg.kg‐1 e 1 mg.kg‐1, respectivamente. A profundidade da anestesia foi medida pelo Índice Bispectral (BIS). O método up‐and‐down foi usado para calcular a CE50 do propofol. Durante o período de equilíbrio, se o valor do BIS fosse ≤ 50 ou BIS > 50, o próximo paciente tinha a infusão de propofol ajustada para uma concentração alvo‐controlada 0,5 µg.mL‐1 inferior ou superior, respectivamente. Os dados hemodinâmicos foram registrados no início do estudo, 10 minutos após a administração de FA, após a indução, após a intubação e 15 minutos após a intubação. Resultados A CE50 do propofol foi menor no Grupo C (2,32 µg.mL‐1, Intervalo de Confiança de 95% [95% IC] 1,85–2,75) e D (2,39 µg.mL‐1, 95% IC 1,91–2,67) do que no Grupo A (2,96 µg.mL‐1; 95% IC 2,55–3,33) (p = 0,023, p = 0,048, respectivamente). Não houve diferenças significantes na CE50 entre o Grupo B (2,53 µg.mL‐1, 95% IC 2,33–2,71) e o Grupo A (p > 0,05). Não houve diferenças significantes na Frequência Cardíaca (FC) entre os grupos A, B e C. A FC foi significantemente menor no grupo D do que no grupo A após a intubação (66 ± 6 vs. 80 ± 10 bpm, p < 0,01) e 15 minutos após a intubação (61 ± 4 vs. 70 ± 8 bpm, p < 0,01). Não houve diferenças significantes entre os quatro grupos na Pressão Arterial Média (PAM) em qualquer momento. A PAM dos quatro grupos foi significantemente menor após a indução, após a intubação e 15 minutos após a intubação do que na linha de base (p < 0,05). Conclusão FA em altas doses (0,75 mg.kg‐1 ou 1 mg.kg‐1) reduz a CE50 do propofol, e 1 mg.kg‐1 de FA reduz a FC durante níveis adequados de anestesia em pacientes não estimulados. Embora esse resultado deva ser investigado na presença de estimulação cirúrgica, sugerimos que a pré‐administração de FA pode reduzir a necessidade de propofol durante anestesia cuja profundidade seja monitorada pelo BIS.

Abstract Background and objectives Preoperative use of flurbiprofen axetil (FA) is extensively adopted to modulate the effects of analgesia. However, the relationship between FA and sedation agents remains unclear. In this study, we aimed to investigate the effects of different doses of FA on the median Effective Concentration (EC50) of propofol. Methods Ninety-six patients (ASA I or II, aged 18–65 years) were randomly assigned into one of four groups in a 1:1:1:1 ratio. Group A (control group) received 10 mL of Intralipid, and groups B, C and D received 0.5 mg.kg−1, 0.75 mg.kg−1 and 1 mg.kg−1 of FA, respectively, 10 minutes before induction. The depth of anesthesia was measured by the Bispectral Index (BIS). The “up-and-down” method was used to calculate the EC50 of propofol. During the equilibration period, if BIS ≤ 50 (or BIS > 50), the next patient would receive a 0.5 µg.mL−1-lower (or -higher) propofol Target-Controlled Infusion (TCI) concentration. The hemodynamic data were recorded at baseline, 10 minutes after FA administration, after induction, after intubation and 15 minutes after intubation. Results The EC50 of propofol was lower in Group C (2.32 µg.mL−1, 95% Confidence Interval [95% CI] 1.85–2.75) and D (2.39 µg.mL−1, 95% CI 1.91–2.67) than in Group A (2.96 µg.mL−1, 95% CI 2.55–3.33) (p = 0.023, p = 0.048, respectively). There were no significant differences in the EC50 between Group B (2.53 µg.mL−1, 95% CI 2.33–2.71) and Group A (p > 0.05). There were no significant differences in Heart Rate (HR) among groups A, B and C. The HR was significantly lower in Group D than in Group A after intubation (66 ± 6 vs. 80 ± 10 bpm, p < 0.01) and 15 minutes after intubation (61 ± 4 vs. 70 ± 8 bpm, p < 0.01). There were no significant differences among the four groups in Mean Arterial Pressure (MAP) at any time point. The MAP of the four groups was significantly lower after induction, after intubation, and 15 minutes after intubation than at baseline (p < 0.05). Conclusion High-dose FA (0.75 mg.kg−1 or 1 mg.kg−1) reduces the EC50 of propofol, and 1 mg.kg−1 FA reduces the HR for adequate anesthesia in unstimulated patients. Although this result should be investigated in cases of surgical stimulation, we suggest that FA pre-administration may reduce the propofol requirement when the depth of anesthesia is measured by BIS.

BACKGROUND: The aim of this study was to explore epilepsy-related mechanism so as to figure out the possible targets for epilepsy treatment. METHODS: The gene expression profile dataset GES32534 was downloaded from Gene Expression Omnibus database. We identified the differentially expressed genes (DEGs) by Affy package. Then the DEGs were used to perform gene ontology (GO) and pathway enrichment analyses. Furthermore, a protein-protein interaction (PPI) network was constructed with the DEGs followed by co-expression modules construction and analysis. RESULTS: Total 420 DEGs were screened out, including 214 up-regulated and 206 down-regulated genes. Functional enrichment analysis revealed that down-regulated genes were mainly involved in the process of immunity regulation and biological repairing process while up-regulated genes were closely related to transporter activity. PPI network analysis showed the top ten genes with high degrees were all down-regulated, among which FN1 had the highest degree. The up-regulated and down-regulated DEGs in the PPI network generated two obvious sub-co-expression modules, respectively. In up-co-expression module, SCN3B (sodium channel, voltage gated, type III beta subunit) was enriched in GO:0006814 ~ sodium ion transport. In down-co-expression module, C1QB (complement C1s), CIS (complement component 1, S subcomponent) and CFI (complement factor I) were enriched in GO:0006955 ~ immune response. CONCLUSION: The immune response and complement system play a major role in the pathogenesis of epilepsy. Additionally, C1QB, C1S, CFI, SCN3B and FN1 may be potential therapeutic targets for epilepsy.

A series of three new benzohydrazone derivatives, N'-(2-hydroxy-5-methylbenzylidene)-4-methylbenzohydrazide (1), N'-(2-hydroxy-5-methylbenzylidene)-4-hydroxybenzohydrazide (2), and N'-(2-hydroxy-5-methylbenzylidene)-4-dimethylaminobenzohydrazide (3), were prepared and characterized by elemental analysis, Ή and 13C NMR, and single crystal X-ray diffraction. Compound (1) crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 27.421(1) Å, b = 9.9843(4) Å, c = 24.302(1) Å, β = 119.416(2)°, V = 5795.7(5) ų, Z = 16, R1 = 0.0520, and wR2 = 0.1172. Compound (2) crystallizes in the orthorhombic space group Pna2(1) with unit cell dimensions a = 9.511(2) Å, b = 9.866(2) Å, c = 13.871(3) Å, V = 1301.6(5) ų, Z = 4, R1 = 0.0342, and wR2 = 0.0912. Compound (3) crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 26.957(2) Å, b = 10.0612(9) Å, c = 25.526(2) Å, β = 114.405(3)°, V= 6304.5(10) ų, Z = 16, R1 = 0.0532, and wR2 = 0.1079. X-ray diffraction indicated that the benzohydrazone molecules of the compounds display trans configuration with respect to the C=N double bonds. The crystal structures of the compounds are stabilized by hydrogen bonds and weak π···π interactions.

Objective To analyse the epidemiology of measles in China and determine the progress made towards the national elimination of the disease. Methods We analysed measles surveillance data – on the age, sex, residence and vaccination status of each case and the corresponding outcome, dates of onset and report and laboratory results – collected between January 2005 and October 2013. Findings Between 2005 and October 2013, 596 391 measles cases and 368 measles-related deaths were reported in China. Annual incidence, in cases per 100 000 population, decreased from 9.95 in 2008 to 0.46 in 2012 but then rose to more than 1.96 in 2013. The number of provinces that reported an annual incidence of less than one case per million population increased from one in 2009 to 15 in 2012 but fell back to one in 2013. Median case age decreased from 83 months in 2005 to 14 months in 2012 and 11 months in January to October 2013. Between 2008 and 2012, the incidence of measles in all age groups, including those not targeted for vaccination, decreased by at least 93.6%. However, resurgence started in late 2012 and continued into 2013. Of the cases reported in January to October 2013, 40% were aged 8 months to 6 years. Conclusion Although there is evidence of progress towards the elimination of measles from China, resurgence in 2013 indicated that many children were still not being vaccinated on time. Routine immunization must be strengthened and the remaining immunity gaps need to be identified and filled.

Resumen Objetivo Analizar la epidemiología del sarampión en China y determinar el progreso hecho hacia la erradicación nacional de la enfermedad. Métodos Hemos analizado los datos de vigilancia del sarampión recogidos entre enero de 2005 y octubre de 2013 en base a la edad, el sexo, la residencia y el estado de vacunación de cada caso y el resultado correspondiente, las fechas de inicio de la enfermedad y de su comunicación, y los resultados de laboratorio. Resultados Entre 2005 y octubre de 2013, se registraron 596 391 casos de sarampión y 368 muertes relacionadas con el sarampión en China. La incidencia anual, en casos por 100 000 habitantes, descendió del 9,95 en 2008 al 0,46 en 2012, pero volvió a aumentar en el 2013 hasta más del 1,96. El número de provincias que informó acerca de una incidencia anual de menos de un caso por millón de habitantes aumentó de una en 2009 a 15 en 2012, pero volvió a caer a una en 2013. La edad media de los casos disminuyó de 83 a 14 meses en 2012, y a 11 meses de enero a octubre de 2013. Entre 2008 y 2012, la incidencia del sarampión en todos los grupos de edad, incluidos los que no estaban incluidos en la vacunación, se redujo en al menos un 93,6 %. Sin embargo, un resurgimiento comenzó a finales de 2012 y continuó en 2013. De los casos comunicados de enero a octubre de 2013, el 40 % tenía entre 8 meses y 6 años. Conclusión Aunque hay pruebas de los progresos hacia la erradicación del sarampión en China, el resurgimiento en el año 2013 mostró que todavía hay muchos niños que no reciben la vacuna a tiempo. Es necesario reforzar la vacunación sistemática e identificar y completar las lagunas restantes en la inmunización.

Résumé Objectif Analyser l'épidémiologie de la rougeole en Chine et déterminer les progrès réalisés sur la voie de l'élimination nationale de la maladie. Méthodes Nous avons analysé les données de surveillance de la rougeole – concernant l'âge, le sexe, le lieu de résidence et le statut vaccinal de chaque cas et les résultats correspondants, les dates de l'apparition et de signalement de la maladie, et les résultats de laboratoire –collectées entre janvier 2005 et octobre 2013 Résultats Entre 2005 et octobre 2013, 596 391 cas de rougeole et 368 décès liés à la rougeole ont été signalés en Chine. L'incidence annuelle exprimée en cas pour 100 000 habitants a diminué de 9,95 en 2008 à 0,46 en 2012, mais a ensuite augmenté à plus de 1,96 en 2013. Le nombre de provinces ayant signalé une incidence annuelle inférieure à un cas pour un million d'habitants a augmenté de 1 en 2009 à 15 en 2012, mais est retombé à 1 en 2013. L'âge médian des cas a diminué de 83 mois en 2005 à 14 mois en 2012 et à 11 mois pendant la période allant de janvier à octobre 2013. Entre 2008 et 2012, l'incidence de la rougeole dans tous les groupes d'âge, y compris ceux qui ne sont pas ciblés pour la vaccination, a diminué d'au moins 93,6%. Cependant, la résurgence a commencé à la fin de l'année 2012 et s'est poursuivie en 2013. Parmi les cas signalés de janvier à octobre 2013, 40% étaient âgés de 8 mois à 6 ans. Conclusion Bien qu'il y ait des preuves de progrès vers l'objectif d'élimination de la rougeole en Chine, la résurgence de 2013 indique que de nombreux enfants n'étaient toujours pas vaccinés à temps. La vaccination de routine doit être renforcée et les lacunes immunitaires restantes doivent être identifiées et comblées.

An efficient, convenient and inexpensive CuI-catalyzed method for the synthesis of 1,2-dichlorovinylphosphine oxides from substituted phosphites, diphenylphosphine oxide and 1,2-dichloroethyne has been developed in moderate-good yields, and the reactions provided mainly regioselective anti addition products.

Uma técnica de microextração em fase líquida foi desenvolvida para a extração e determinação de quantidades traço de íons cádmio em amostras de água. A emulsificação-microextração assistida por ultrasom através da gota orgânica flutuante solidificada (USAE-SFODME) foi empregada para a extração e a espectrometria de absorção atômica com chama (FAAS) foi empregada para a determinação de Cd. Foram investigados e otimizados os fatores que influenciam na eficiência da técnica de microextração, tais como tipo e volume de solvente, tempo, temperatura, pH, quantidade do agente quelante e efeito da concentração de cloreto de sódio. Usando as condições otimizadas, um fator do enriquecimento de 81,0 foi obtido para um volume de 6,0 mL de amostra de água. A curva analítica de calibração mostrou-se linear no intervalo de 10-450 µg L-1 com um limite de detecção (LOD) igual a 0,66 µg L-1 de Cd. Os desvios padrão relativos (RSD) para dez replicatas de soluções contendo 20 e 300 µg L-1 de Cd foram 3,34% e 2,42%, respectivamente. O método proposto foi avaliado pela determinação de Cd em material de referência certificado de água ou através de experimentos de adição e recuperação

A liquid-phase microextraction technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction (USAE-SFODME) combined with flame atomic absorption spectrometry (FAAS) for the extraction and determination of trace cadmium in water samples. Microextraction efficiency factors, such as extraction solvent type and extraction volume, time, temperature, pH, the amount of the chelating agent, and salt effect, were investigated and optimized. Under optimum conditions, an enrichment factor of 81.0 was obtained for 6.0 mL of water sample. The calibration graph was linear in the range of 10-450 mg L-1 with a detection limit of 0.66 µg L-1. The relative standard deviations (RSD) for ten replicate measurements of 20 and 300 µg L-1 of Cd were 3.34% and 2.42%, respectively. The accuracy of the proposed method was assessed either by determination of Cd in a certified reference material of water or by addition-recovery experiments

Foi desenvolvido um método altamente sensível, seletivo e rápido para a determinação de mercúrio, a partir da reação rápida de mercúrio(II) com 5-(p-aminobenzilideno)-tiorodanina (ABTR) e posterior extração em fase sólida do quelato colorido, utilizando discos C18. Em pH 3,5 e na presença do emulsificante-OP, ABTR reage com mercúrio(II) para formar um quelato vermelho na razão molar 1:2 (mercúrio:ABTR). O quelato foi enriquecido pela extração em fase sólida com discos C18 e o quelato retido, eluído com dimethyl formamida (DMF). Um fator de enriquecimento na ordem de 50 foi obtido. Em DMF, a absortividade molar do quelato é 1,21<FONT FACE=Symbol>´</FONT>10(5) L mol-1 cm-1 a 545 nm, e a lei de Beer é obedecida no intervalo 0,01~3 µg mL-1 na solução medida. O desvio padrão relativo para onze replicatas a 0,01 µg mL-1 é 1,7%. Este método foi aplicado para a determinação de mercúrio em tabaco e aditivos de tabaco. Bom coeficiente de preconcentração foi encontrado, comparando-se o método proposto com outros similares.

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5-(p-aminobenzylidene)-thiorhodanine (ABTR) and the solid phase extraction of the colored chelate with C18 disks has been developed. At pH 3.5 and in the presence of emulsifier-OP medium, ABTR reacts with mercury(II) to form a red chelate of a 1:2 (mercury to ABTR) molar ratio. This chelate was enriched by solid phase extraction with C18 disks and the retained chelate eluted form the disks with dimethyl formamide (DMF). An enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.21<FONT FACE=Symbol>´</FONT>10(5) L mol-1 cm-1 at 545 nm, and Beer's law is obeyed in the 0.01~3 µg mL-1 range in the measured solution. The relative standard deviation for eleven sample replicate measurements at the 0.01 µg mL-1 level is 1.7%. This method was applied to the determination of mercury in tobacco and tobacco additives and good preconcentration was found between proposed and comparative methods results.