Cantilever micro-rheometer for the dcharacterization of sugar solutions

The volume required for the rheological characterization of fluids can be minimized by using micromechanical cantilevers as viscosity sensors. Here, a simple measurement tool for the characterization of sugar solutions is proposed. The sensor consists of a micromechanical cantilever as used in an atomic force microscopy which is integrated into a closed fluid handling system. Fluid properties are derived from an analysis of the power spectral density of the fluctuations of the cantilever deflection signal. The data acquisition system is operated with standard consumer computer components, which limits the costs for the hardware. Measurements with different sugar solutions indicate that the sensor system provides reliable viscosity values for sugar concentrations as they occur in biological systems. The viscosities of the sugar solutions could be evaluated with an error smaller than 5%

Adoleszenz, symbolische Gewalt und weibliche Identität im Kontext von Beziehungsgewalt gegen Frauen: Impulse für eine geschlechterreflexive Beratung unter Berücksichtigung der Bindungstheorie und des Habituskonzeptes

Hennemeyer JM. Adoleszenz, symbolische Gewalt und weibliche Identität im Kontext von Beziehungsgewalt gegen Frauen: Impulse für eine geschlechterreflexive Beratung unter Berücksichtigung der Bindungstheorie und des Habituskonzeptes. Bielefeld: Universität Bielefeld; 2016

Comparison between Deflection and Vibration Characteristics of Rectangular and Trapezoidal profile Microcantilevers

Arrays of microcantilevers are increasingly being used as physical, biological, and chemical sensors in various applications. To improve the sensitivity of microcantilever sensors, this study analyses and compares the deflection and vibration characteristics of rectangular and trapezoidal profile microcantilevers. Three models of each profile are investigated. The cantilevers are analyzed for maximum deflection, fundamental resonant frequency and maximum stress. The surface stress is modelled as in-plane tensile force applied on the top edge of the microcantilevers. A commercial finite element analysis software ANSYS is used to analyze the designs. Results show paddled trapezoidal profile microcantilevers have better sensitivity

Cantilever Micro-rheometer for the Characterization of Sugar Solutions

The volume required for the rheological characterization of fluids can beminimized by using micromechanical cantilevers as viscosity sensors. Here, a simplemeasurement tool for the characterization of sugar solutions is proposed. The sensorconsists of a micromechanical cantilever as used in an atomic force microscopy which isintegrated into a closed fluid handling system. Fluid properties are derived from an analysisof the power spectral density of the fluctuations of the cantilever deflection signal. The dataacquisition system is operated with standard consumer computer components, which limitsthe costs for the hardware. Measurements with different sugar solutions indicate that thesensor system provides reliable viscosity values for sugar concentrations as they occur inbiological systems. The viscosities of the sugar solutions could be evaluated with an errorsmaller than 5 %

Microspheres embolization of juvenile nasopharyngeal angiofibroma in an adult

INTRODUCTION: Juvenile nasopharyngeal angiofibroma (JNA) is a benign though locally aggressive, highly vascular tumor primarily affecting adolescent males which has traditionally posed a significant intraoperative challenge during its resection due to the high risk of uncontrollable hemorrhage. Pre-operative angiographic embolization of the major feeding vessels to the tumor has become a valuable, even necessary, tool in the surgical treatment of these lesions. PRESENTATION OF CASE: Our patient was a 32-year-old man with a chief complaint of recurrent left-sided epistaxis for one year, brisk and continuous for ten days prior to presentation, subsequently found to have a 4 cm vascular skull base tumor causing mild expansion of the pterygopalatine fossa. The patient underwent pre-operative embolization utilizing 300–500 micrometer microspheres injected into the ipsilateral maxillary artery. The following day, the patient underwent definite Stereotactical surgical resection of his JNA tumor. Estimated blood loss during the operation was 50 mL, and the patient was discharged the same day. DISCUSSION: Juvenile nasopharyngeal angiofibromas pose a significant bleeding risk for the surgeon due to their highly vascular nature. Pre-operative embolization of juvenile nasopharyngeal angiofibromas can reduce intraoperative blood loss while lessening the risk of massive hemorrhage, shortening operation times, increasing intra-operative visibility, and allowing for easier resection of lesions. CONCLUSION: Pre-operative embolization of JNA is a safe, effective method to prevent against the risk of massive, sometimes fatal, hemorrhage that occurs with these highly vascular tumors