18 research outputs found

    A four-quadrant switched capacitor DC-DC convertor enabling power-efficient lab-grade potentiostats

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    This paper presents a low-power potentiostat based on a four-quadrant switched capacitor DC-DC convertor for use in lab applications. The gearbox convertor achieves a compliance voltage of ±2.5V. Through the use of frequency scaling, the convertor features output currents in the range of 1µA to 1mA, outclassing other state-of-the-art power efficient potentiostats. A hysteretic control loop and a seperate hysteretic comparator allow the potentiostat to be used for both voltammetric and ampere-metric experiments. Simulations demonstrate a peak efficiency of 87%, and a competitive overall efficiency. The system is designed and simulated in a 0.35µm process

    Hair care device and method for enhancing uptake of a topical in hair

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    A hair care device for enhancing uptake of a topical in hair. The hair care device comprises a topical delivery unit for applying the topical to the hair surface, an ultrasound generator (103) for generating ultrasound at a frequency exceeding 15 MHz, wherein an ultrasound intensity is in a range between 2 W/cm2 and 100 W/cm2, and an ultrasound transducer (105) for applying ultrasound to the topical and/or the hair surface to enhance uptake of the topical by the hair.</p

    Hair styling

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    On a hair styling device (20), a light emitting diode (33) is configured to deliver optical energy to hair, wherein an energy fluence of the optical energy is between 0.5 and 9 J/cm2, and more preferably between 1 and 5 J/cm2. The light emitting diode (33) is pulse- driven, and a pulse width of the optical energy is at least 50 ms. An output wavelength of the optical energy may be between 400 and 900 nm. The pulse width of the optical energy is preferably between 50 and 300 ms. The hair styling device (20) may comprise an optical shield (32) configured to block stray light during light exposure of the hair. An inner surface of the optical shield (32) may be reflective and/or may have a parabolic shape. The optical shield (32) may be movable between an open position in which a lock of hair can be placed in the hair styling device (20) while the optical energy is not applied, and a closed position in which light is prevented from escaping the hair styling device (20) while the optical energy is applied to the hair. The hair styling device may be a hair straightener having opposing first and second straightening surfaces, of which at least the first straightening surface comprises the light emitting diode (33), and at least the second straightening surface is arranged for reflecting light from the light emitting diode (33).</p

    Lack of guilt, guilt, and shame:a multi-informant study on the relations between self-conscious emotions and psychopathology in clinically referred children and adolescents

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    The present study examined the relationships between dysregulations in self-conscious emotions and psychopathology in clinically referred children and adolescents. For this purpose, parent-, teacher-, and self-report Achenbach System of Empirically Based Assessment data of 1000 youth aged 4–18 years was analyzed as this instrument not only provides information on the intensity levels of lack of guilt, guilt, and shame, but also on the severity of various types of psychopathology. The results first of all indicated that dysregulations of self-conscious emotions were more common in this clinical sample than in the general population. Further, a consistent pattern was found with regard to the relationships between self-conscious emotions and childhood psychopathology. That is, lack of guilt was predominantly associated with oppositional defiant and conduct (i.e., externalizing) problems, while guilt and shame were primarily linked with affective and anxiety (i.e., internalizing) problems. By and large, these findings confirm what has been found in non-clinical youth, and suggest that self-conscious emotions play a small but significant role in the psychopathology of children and adolescents

    Hair styling

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    On a hair styling device (20), a light emitting diode (33) is configured to deliver optical energy to hair, wherein an energy fluence of the optical energy is between 0.5 and 9 J/cm2, and more preferably between 1 and 5 J/cm2. The light emitting diode (33) is pulse- driven, and a pulse width of the optical energy is at least 50 ms. An output wavelength of the optical energy may be between 400 and 900 nm. The pulse width of the optical energy is preferably between 50 and 300 ms. The hair styling device (20) may comprise an optical shield (32) configured to block stray light during light exposure of the hair. An inner surface of the optical shield (32) may be reflective and/or may have a parabolic shape. The optical shield (32) may be movable between an open position in which a lock of hair can be placed in the hair styling device (20) while the optical energy is not applied, and a closed position in which light is prevented from escaping the hair styling device (20) while the optical energy is applied to the hair. The hair styling device may be a hair straightener having opposing first and second straightening surfaces, of which at least the first straightening surface comprises the light emitting diode (33), and at least the second straightening surface is arranged for reflecting light from the light emitting diode (33).</p

    Hair care device and method for enhancing uptake of a topical in hair

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    A hair care device for enhancing uptake of a topical in hair. The hair care device comprises a topical delivery unit for applying the topical to the hair surface, an ultrasound generator (103) for generating ultrasound at a frequency exceeding 15 MHz, wherein an ultrasound intensity is in a range between 2 W/cm2 and 100 W/cm2, and an ultrasound transducer (105) for applying ultrasound to the topical and/or the hair surface to enhance uptake of the topical by the hair.</p

    Hair care device

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    A hair care device (100) comprises a heat source (103) for heating hair up till a first temperature that is no more than 150 °C (and thus lower than a critical temperature at which hair cuticle damage will occur), and a radiation source (102) for - in combination with heat from the heat source (103) - selectively heating a hair cortex to a second temperature exceeding the first temperature and sufficiently high for hair styling.</p

    Quartz and respirable dust in the Dutch construction industry : A baseline exposure assessment as part of a multidimensional intervention approach

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    Quartz exposure can cause several respiratory health effects. Although quartz exposure has been described in several observational workplace studies, well-designed intervention studies that investigate the effect of control strategies are lacking. Tis article describes a baseline exposure study that is part of a multidimensional intervention program aiming to reduce quartz exposure among construction workers. In this study, personal respirable dust and quartz exposure was assessed among 116 construction workers (bricklayers, carpenters, concrete drillers, demolishers, and tuck pointers). Possible determinants of exposure, like job, tasks, and work practices, use of control measures, and organizational and psychosocial factors, were explored using exposure models for respirable dust and quartz separately. Stratified analyses by job title were performed to evaluate the effect of control measures on exposure and to explore the association between control measures and psychosocial factors. Overall, 62% of all measurements exceeded the Dutch occupational exposure limit for quartz and 11% for respirable dust. Concrete drillers and tuck pointers had the highest exposures for quartz and respirable dust (0.20 and 3.43 mg m-3, respectively). Significant predictors of elevated quartz exposure were abrasive tasks and type of material worked on. Surprisingly, in a univariate model, an increased knowledge level was associated with an increase in exposure. Although control measures were used infrequently, if used they resulted in approximately 40% reduction in quartz exposure among concrete drillers and tuck pointers. Only among concrete drillers, the use of control measures was associated with a higher score for social influence (factor 1.6); knowledge showed an inverse association with use of control measures for concrete drillers, demolishers, and tuck pointers. In conclusion, the detailed information on determinants of exposure, use of control measures, and constraints to use these control measures can be used for the determination and systematic prioritization of intervention measures used to design and implement our intervention strategy. Tis study underlines the need for multidisciplinary workplace exposure control strategies although larger study populations are necessary to determine a possible causal association between organizational and psychosocial factors and psychosocial factors and control measures
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