A novel micro- and nano-scale positioning sensor based on radio frequency resonant cavities.

In many micro- and nano-scale technological applications high sensitivity displacement sensors are needed, especially in ultraprecision metrology and manufacturing. In this work a new way of sensing displacement based on radio frequency resonant cavities is presented and experimentally demonstrated using a first laboratory prototype. The principle of operation of the new transducer is summarized and tested. Furthermore, an electronic interface that can be used together with the displacement transducer is designed and proved. It has been experimentally demonstrated that very high and linear sensitivity characteristic curves, in the range of some kHz/nm; are easily obtainable using this kind of transducer when it is combined with a laboratory network analyzer. In order to replace a network analyzer and provide a more affordable, self-contained, compact solution, an electronic interface has been designed, preserving as much as possible the excellent performance of the transducer, and turning it into a true standalone positioning sensor. The results obtained using the transducer together with a first prototype of the electronic interface built with cheap discrete elements show that positioning accuracies in the micrometer range are obtainable using this cost-effective solution. Better accuracies would also be attainable but using more involved and costly electronics interfaces.

Pharmacokinetic and pharmacodynamic properties of enrofloxacin in southern crested caracaras (Caracara plancus).

To determine the dosage of enrofloxacin in southern crested caracaras (Caracara plancus), plasma concentrations of enrofloxacin were measured by high-performance liquid chromatography after intravenous (IV) (5 mg/kg) and intramuscular (IM) (10 mg/kg) administration. This compound presented a relatively high volume of distribution (2.09 L/kg), a total body clearance of 0.24 L/kg x h, and a long permanence as shown by an elimination half-life of 7.81 hours after IV administration and a terminal half-life of 6.58 hours after IM administration. The areas under the concentration-time curves (AUC) were 21.92 and 34.38 microg x h/mL for IM and IV administration, respectively. Enrofloxacin was rapidly absorbed after IM administration with a time to reach maximum concentration of 0.72 hours and bioavailability of 78.76%. After IM administration, the peak drug concentration (C(max)) was 3.92 microg/mL. Values of minimum inhibitory concentration (MIC), C(max), and AUC have been used to predict the clinical efficacy of a drug in treating bacterial infections, with a C(max)/MIC value of 10 and an AUC/MIC ratio of 125-250 associated with optimal bactericidal effects. By using the study data and a MIC breakpoint of 0.25 microg/mL, values of C(max)/MIC were 13.74 and 15.94 and for AUC/MIC were 90.73 and 139.63, for the IV and IM routes respectively. For the treatment of infectious diseases caused by microorganisms with MIC < or = 0.25 microg/mL, the calculated optimal dosages were 7.5 and 9.5 mg/kg q24h by the IV and IM routes, respectively. For less susceptible bacteria, a dose increase should be evaluated. To treat caracara by the IV route against microorganisms with MIC < or = 0.25 microg/mL, the dose should be higher than the 5 mg/kg used in our study, but possible side effects derived from an increase in the IV dose and efficacy in sick birds should be assessed.

Prevalence of diabetes mellitus and impaired glucose tolerance in the urban population aged 30-69 years in Ribeirão Preto (São Paulo), Brazil

CONTEXTO: A prevalência de diabetes mellitus tem aumentado, em decorrência das mudanças no estilo de vida e do aumento da expectativa de vida da população. . No Brasil, o estudo que avaliou as prevalências de diabetes e intolerância a glicose foi o Estudo Multicêntrico Brasileiro, realizado de 1986 a 1988. OBJETIVO: Determinar a prevalência de diabetes e intolerância a glicose na população urbana, de 30 a 69 anos, do município de Ribeirão Preto (SP), Brasil. TIPO DE ESTUDO: Estudo transversal com inquérito domiciliar em duas etapas. LOCAL: Ribeirão Preto, São Paulo, Brasil. PARTICIPANTES: Amostra randomizada de 1.473 indivíduos. MÉTODOS: O planejamento amostral adotado foi de conglomerados em estágios considerando sexo, faixa etária e renda do chefe dos domicílios Os indivíduos eram rastreados com glicemia capilar de jejum (GCJ). Aqueles com resultado positivo (glicemia capilar em jejum > 100 mg/dl) e a cada sétimo com resultado negativo (< 100 mg/dl) eram submetidos a sobrecarga oral com 75 g de glicose. Os diagnósticos de diabetes e intolerância a glicose foram baseados nos critérios da Organização Mundial da Saúde. RESULTADOS: As prevalências de diabetes e de intolerância a glicose foram de 12,1 e de 7,7 por cento, respectivamente. Homens e mulheres apresentaram freqüências semelhantes de diabetes (12,0 versus 12,1 por cento) e intolerância a glicose (7,9 versus 7,3 por cento). Diferenças entre brancos (11,6 por cento) e não-brancos (13,3 por cento) para diabetes não foram significantes, enquanto a intolerância a glicose foi mais prevalente em brancos . As prevalências de diabetes e intolerância a glicose variaram de 3,3 por cento e 2,6 por cento, no grupo de 30-39 anos, a 21,7 por cento e 11,3 por cento no grupo de 60-69 anos, respectivamente. Indivíduos obesos (índice de massa corpórea > 30 kg/m2) e aqueles com história familiar de diabetes (parentes de primeiro grau) apresentaram prevalência maior de diabetes: 22,6 por cento e 19,7 por cento, respectivamente. CONCLUSÕES: A prevalência de diabetes em Ribeirão Preto se mostrou comparável à observada em países desenvolvidos. Em relação ao Estudo Multicêntrico Brasileiro, verificamos maior prevalência de diabetes, mas prevalência semelhante de intolerância a glicose. Estes achados podem refletir o impacto dos fatores ambientais e de estilo de vida, que têm ocorrido em cidades brasileiras como Ribeirão Preto, principalmente nas taxas crescentes de sedentarismo e obesidade.