Determination of cyanamide in workplace air by high-performance liquid chromatography / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a method for determining cyanamide in workplace air by high-performance liquid chromatography (HPLC).</p><p><b>METHODS</b>Air samples were collected from the workplace using the shock absorption tube containing water solution at a rate of 2.8∼3.0 ml/min for 60 min; dansyl chloride was used as a derivatization reagent to conduct pre-column derivatization, and the procedure was as follows: acetone solution (2.5 ml), mixed solution (1.0 ml) containing 0.016 mol/L Na2CO3 and 0.184 mol/L NaHCO3, and 10 mg/ml acetone solution of dansyl chloride (0.5 ml) were added into the samples, and reaction proceeded in a water bath (50 °C) for 1 h. HPLC was performed on an ODS C18 column (250 mm × 4.6 mm, 5 üm) with a mobile phase of acetonitrile-phosphate buffer (35:65) at a flow rate of 1.0 ml/min and a column temperature of 25°C; a fluorescence detector was used at an excitation wavelength of 360 nm and an emission wavelength of 495 nm.</p><p><b>RESULTS</b>The minimum detectable concentration of cyanamide was 0.05 üg/ml; a good linear relationship was noted when the concentration of cyanamide was 0.2∼100.0 üg/ml; the intraday relative standard deviation (RSD) was 0.28%∼1.18%, and the interday RSD was 0.22∼2.16%; the recovery rate was 95.7%∼103.0%, and the sampling efficiency was 95.8%∼96.9%. Water solution of cyanamide (pH<6.5) could be stable in the dark at room temperature for 7 d.</p><p><b>CONCLUSION</b>This method is stable, reliable, easy to operate, and highly sensitive and suitable for determination of cyanamide in workplace air.</p>

Avaliação clínica do clareamento dental pela técnica no consultório / Clinical evaluate of the dental bleaching technique in the office

Este trabalho teve como objetivo avaliar clinicamente a alteração de cor, a sensibilidade dental e a irritação gengival em pacientes submetidos ao clareamento dental. Selecionados 40 pacientes que foram divididos aleatoriamente em 4 grupos: G1 - Peróxido de Hidrogênio (PH) a 35%; G2 - PH a 35% + Luz Halógena Curing Light XL 3000 (3M/ESPE); G3 - PH a 35% + LED Demetron (Kerr) e G4 - PH a 35% + Led/Laser (DMC). Para todos os grupos foi realizado 2 sessões de clareamento com PH a 35% (intervalo de 1 semana), com 3 aplicações do gel em cada sessão. Para avaliação da cor obtida antes a após a 1ª e 2ª sessões do tratamento clareador, foi utilizado dois métodos de avaliação: I - Espectrofotômetro VITA Easyshade; e II - Escala de cor da Vita Clássica. No teste estatístico de ANOVA foi observada a hipótese de igualdade entre os grupos avaliando o fator Grupo e diferença no fator Tempo. O tratamento clareador de dentes vitais através da técnica no consultório com peróxido de hidrogênio a 35%, não melhorou com o uso de fontes auxiliares. Uma sessão clínica através da técnica no consultório não é suficiente para o clareamento de dentes vitais.

Cutaneous reactions simulating erythema multiforme and Stevens Johnson syndrome due to occupational exposure to a plant-growth regulator.

BACKGROUND: In India, hydrogen cyanamide (Dormex) is a plant growth regulator used mainly for the bud-breaking of grapevines. The use of this chemical may result in severe cutaneous reactions simulating erythema multiforme (EM), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). METHODS: Studies were conducted on four seasonal grapevine workers who developed severe cutaneous reactions following the unprotected use of Dormex (hydrogen cyanamide). RESULTS: Two of the patients had EM-like skin lesions and the other two developed SJS-TEN-like skin lesions. A latent period of 5-7 days existed between the contact with the chemical and the development of the skin lesions. The histopathological picture was suggestive of EM. All the patients responded to systemic steroids and antihistamines. CONCLUSIONS: Hydrogen cyanamide may act as a hapten, initiating cytotoxic immunological attack on keratinocytes, resulting in EM- and SJS-TEN-like clinical picture. Awareness regarding such severe cutaneous reactions due to the inappropriate handling of Dormex is required. The use of personal protection equipment while handling agricultural chemicals is essential.

Época de poda e quebra de dormência em videiras cv. Niagara Rosada / Times of prunning and budbreaking in Niagara Rosada vines

O experimento foi conduzido com o objetivo de verificar a eficiência da combinação de cinco concentraçõesde cianamida hidrogenada (CH) e quatro épocas de poda, na quebra da dormência e antecipação dacolheita da videira ‘Niagara Rosada’ no município de Ponta Grossa – PR. O delineamento experimentalfoi em blocos casualizados no esquema fatorial 4 x 5 (épocas de poda x concentrações de CH) , com 3repetições e 3 plantas por parcela. Foram analisados a porcentagem de brotação, o número de cachos porplanta, a produção por planta e a massa média dos cachos. Houve efeito da aplicação de cianamidahidrogenada no aumento da brotação das gemas apenas para a primeira época de poda (06/08/2007). Aprimeira época de poda antecipou em uma semana a colheita, embora a ocorrência de geadas tenhaprejudicado a produção. O atraso na época de poda proporcionou um maior número de cachos por plantae a maior produção.

This research work had as the aim of verifying the efficiency of five combined concentrations of hydrogencyanamide (CH) in four consecutive pruning times of sprouting vine and harvest anticipation of 'NiagaraRosada' in the county of Ponta Grossa, PR. The experiment had a factorial design (4 x 5) with 3 replicationsand 3 plants per parcel. The analysis were sprouting percentage, number of clusters per plant, rate ofproduction and average weight per cluster. The effect of CH was shown only at the first pruned timewhen sprouting but the occurrence of frosting decreased the yield. The delay in the process of pruningshowed a higher number of cluster per plant, which consequently resulted in yield increase