329 research outputs found

    Preparation, Proximate Composition and Culinary Properties of Yellow Alkaline Noodles from Wheat and Raw/Pregelatinized Gadung (Dioscorea Hispida Dennst) Composite Flours

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    The steady increase of wheat flour price and noodle consumptions has driven researchers to find substitutes for wheat flour in the noodle making process. In this work, yellow alkaline noodles were prepared from composite flours comprising wheat and raw/pregelatinized gadung (Dioscorea hispida Dennst) flours. The purpose of this work was to investigate the effect of composite flour compositions on the cooking properties (cooking yield, cooking loss and swelling index) of yellow alkaline noodle. In addition, the sensory test and nutrition content of the yellow alkaline noodle were also evaluated for further recommendation. The experimental results showed that a good quality yellow alkaline noodle can be prepared from composite flour containing 20% w/w raw gadung flour. The cooking yield, cooking loss and swelling index of this noodle were 10.32 g, 1.20 and 2.30, respectively. Another good quality yellow alkaline noodle can be made from composite flour containing 40% w/w pregelatinized gadung flour. This noodle had cooking yield 8.93 g, cooking loss 1.20, and swelling index of 1.88. The sensory evaluation suggested that although the color, aroma and firmness of the noodles were significantly different (p ≤ 0.05) from wheat flour noodle, but their flavor remained closely similar. The nutrition content of the noodles also satisfied the Indonesian National Standard for noodle. Therefore, it can be concluded that wheat and raw/pregelatinized gadung composite flours can be used to manufacture yellow alkaline noodle with good quality and suitable for functional food

    NASA Tech Briefs, November 2007

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    Topics include: Wireless Measurement of Contact and Motion Between Contact Surfaces; Wireless Measurement of Rotation and Displacement Rate; Portable Microleak-Detection System; Free-to-Roll Testing of Airplane Models in Wind Tunnels; Cryogenic Shrouds for Testing Thermal-Insulation Panels; Optoelectronic System Measures Distances to Multiple Targets; Tachometers Derived From a Brushless DC Motor; Algorithm-Based Fault Tolerance for Numerical Subroutines; Computational Support for Technology- Investment Decisions; DSN Resource Scheduling; Distributed Operations Planning; Phase-Oriented Gear Systems; Freeze Tape Casting of Functionally Graded Porous Ceramics; Electrophoretic Deposition on Porous Non- Conductors; Two Devices for Removing Sludge From Bioreactor Wastewater; Portable Unit for Metabolic Analysis; Flash Diffusivity Technique Applied to Individual Fibers; System for Thermal Imaging of Hot Moving Objects; Large Solar-Rejection Filter; Improved Readout Scheme for SQUID-Based Thermometry; Error Rates and Channel Capacities in Multipulse PPM; Two Mathematical Models of Nonlinear Vibrations; Simpler Adaptive Selection of Golomb Power-of- Two Codes; VCO PLL Frequency Synthesizers for Spacecraft Transponders; Wide Tuning Capability for Spacecraft Transponders; Adaptive Deadband Synchronization for a Spacecraft Formation; Analysis of Performance of Stereoscopic-Vision Software; Estimating the Inertia Matrix of a Spacecraft; Spatial Coverage Planning for Exploration Robots; and Increasing the Life of a Xenon-Ion Spacecraft Thruster

    Therapeutic potential of bleomycin plus suicide or interferon-β gene transfer combination for spontaneous feline and canine melanoma

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    We originated and characterized melanoma cell lines derived from tumors of two feline and two canine veterinary patients. These lines reestablished the morphology, physiology and cell heterogeneity of their respective parental tumors. We evaluated the cytotoxicity of bleomycin (BLM) alone, or combined with interferon-β (IFN-β) or HSVtk/GCV suicide gene (SG) lipofection on these cells. Although the four animals presented stage III disease (WHO system), SG treated feline tumors displayed stable disease in vivo, while the canine ones exhibited partial response. Their derived cell lines reflected this behavior. Feline were significantly more sensitive than canine cells to IFN-β gene transfer. BLM improved the antitumor effects of both genes. The higher levels of reactive oxygen species (ROS) significantly correlated with membrane and DNA damages, emphasizing ROS intervention in apoptotic and necrotic cell death. After 3 days of BLM alone or combined with gene treatments, the colony forming capacity of two canine and one feline treatments survivor cells almost disappeared. Taken together, these results suggest that the treatments eradicated tumor initiating cells and support the clinical potential of the tested combinations.Fil: Agnetti, Lucrecia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Fondello, Chiara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Villaverde, Marcela Solange. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Glikin, Gerardo Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Finocchiaro, Liliana Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; Argentin

    Above-IC RF MEMS devices for communication applications

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    Wireless communications are showing an explosive growth in emerging consumer and military applications of radiofrequency (RF), microwave, and millimeter-wave circuits and systems. Applications include wireless personal connectivity (Bluetooth), wireless local area networks (WLAN), mobile communication systems (GSM, GPRS, UMTS, CDMA), satellite communications and automotive electronics. Future cell phones and ground communication systems as well as communication satellites will require more and more sophisticated technologies. The increasing demand for size and weight reduction, cost savings, low power consumption, increased frequency and higher functionality and reconfigurability as part of multiband and multistandard operation is necessitating the use of highly integrated RF front-end circuits. Chip scaling has made a major contribution to this goal, but today a situation has been reached where the presence of numerous off-chip passive RF components imposes a critical bottleneck to further integration and miniaturization of wireless transceivers. Microelectromechanical systems (MEMS) technology is a rapidly emerging enabling technology that is intended to replace the discrete passives by their integrated counterparts. In this thesis, an original metal surface micromachining process, which is compatible with CMOS post-processing, for above-IC integration of RF MEMS tunable capacitors and suspended inductors is presented. A detailed study on SF6 inductively coupled plasma (ICP) releasing has been performed in order to ascertain the optimal process parameters. This study has emphasized the fact that temperature plays an important role in this process by limiting silicon dioxide etching. Moreover, the optimized recipe has been found to be independent of the sacrificial layer used (amorphous or polycrystalline silicon) and its thickness. Using this recipe, 15.6 µm/min Si underetch rate with high Si: SiO2 selectivity (> 20000: 1) has been obtained. Single-air-gap and double-air-gap parallel-plate MEMS tunable capacitors have been designed, fabricated and characterized in the pF range, from 1 MHz to 13.5 GHz. It has been shown that an optimized design of the suspended membrane and direct symmetrical current feed at both ports can significantly improve the quality factor and increase the self-resonant frequency, pushing it to 12 GHz and beyond. The maximum capacitance tuning range obtained for a single-air-gap capacitor is 29% for a bias voltage of 20 V. The maximum capacitance tuning range obtained for a double-air-gap capacitor is 207% for a bias voltage of 70 V. The post-processing of X-FAB BiCMOS wafers has been successfully demonstrated to fabricate monolithically integrated VCOs with above-IC MEMS LC tank. Comparing a suspended inductor and the X-FAB inductor with the same design, it has been shown that increasing the thickness of the spiral from 2.3 to 4 µm and having the spiral suspended 3 µm above the passivation layers lead to an improvement factor of 2 for the peak quality factor and a shift of the self-resonant frequency beyond 15 GHz. No significant variation on bipolar and MOS transistors characteristics due to the post-processing has been observed and we conclude that the variation due to post-processing is in the same range as the wafer-to-wafer variation. Based on our metal surface micromachining process, coplanar waveguide (CPW) MEMS shunt capacitive switches and variable true-time delay lines (V-TTDLs) have been designed, fabricated and characterized in the 1 - 20 GHz range. A novel MEMS device architecture: the SG-MOSFET, which combines a solid-state MOS transistor and a metal suspended gate has been proposed as DC current switch. The corresponding fabrication process using polysilicon as a sacrificial layer has been developed to release metal gate suspended over gate oxide by SF6 plasma. Very abrupt current switches have been demonstrated with subthreshold slope better than 10 mV/decade (better than the theoretical solid-state bulk or SOI MOSFET limit of 60 mV/decade) and ultra-low gate leakage (less than 0.001 pA/µm2) due to the air-gap

    Microfluidics for Soft Electronics

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    Microfluidics- based soft electronic systems have the potential to assist conventional rigid devices and circuits to achieve extreme levels of elasticity in wearable electronics and other applications. The goal of employing microfluidics-based approach among other existing methods is to enhance users comfort through fulfillment of wearable’s mechanical performance requirements such as flexibility, twistability, and stretchability. This chapter presents a brief survey of different solutions for developing elastic electronics and a thorough review of the progress in microfluidics-based approaches. This chapter mainly focuses on the description of the fabrication process, design, and measurement steps of different antennas and complex systems realized using microfluidic interconnects

    Calculation of Thermodynamic Properties of Polyelectrolytes

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    Expressions are derived which introduce an appreciable simplification into the calculation of the thermodynamic properties of solutions of polyelectrolytes in certain cases. For example, for a certain class of theoretical models of these systems it is found that the square of the mean ion activity coefficient of a uni-univalent salt in the presence of polymeric ions is V^2/∫e^(-eψ/kT)dV • ∫e^(eψ/kT)dV, the integration of the potential ψ being over a region whose volume is the volume of solution per macro-ion, V, and whose symmetry is that assumed for the polyelectrolyte. The osmotic pressure of a salt-polyelectrolyte system is, ignoring the contribution of the macro-ion, estimated to be Σ_ic_i^skT, where Σ_ic_i^s is the sum of the concentrations of all ions at the surface bounding the previously defined volume V. Other relations and various applications are given. The activity coefficient of salt in the presence of polyelectrolytes, calculated by extending the "parallel rod" picture of polymeric ions, is found to be in reasonable agreement with the experimental data. The use of the Poisson-Boltzmann equation to estimate ψ in these systems is shown not to render inconsistent several alternative expressions for the electrostatic contribution to the free energy

    Design and Implementation of an Integrated Biosensor Platform for Lab-on-a-Chip Diabetic Care Systems

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    Recent advances in semiconductor processing and microfabrication techniques allow the implementation of complex microstructures in a single platform or lab on chip. These devices require fewer samples, allow lightweight implementation, and offer high sensitivities. However, the use of these microstructures place stringent performance constraints on sensor readout architecture. In glucose sensing for diabetic patients, portable handheld devices are common, and have demonstrated significant performance improvement over the last decade. Fluctuations in glucose levels with patient physiological conditions are highly unpredictable and glucose monitors often require complex control algorithms along with dynamic physiological data. Recent research has focused on long term implantation of the sensor system. Glucose sensors combined with sensor readout, insulin bolus control algorithm, and insulin infusion devices can function as an artificial pancreas. However, challenges remain in integrated glucose sensing which include degradation of electrode sensitivity at the microscale, integration of the electrodes with low power low noise readout electronics, and correlation of fluctuations in glucose levels with other physiological data. This work develops 1) a low power and compact glucose monitoring system and 2) a low power single chip solution for real time physiological feedback in an artificial pancreas system. First, glucose sensor sensitivity and robustness is improved using robust vertically aligned carbon nanofiber (VACNF) microelectrodes. Electrode architectures have been optimized, modeled and verified with physiologically relevant glucose levels. Second, novel potentiostat topologies based on a difference-differential common gate input pair transimpedance amplifier and low-power voltage controlled oscillators have been proposed, mathematically modeled and implemented in a 0.18μm [micrometer] complementary metal oxide semiconductor (CMOS) process. Potentiostat circuits are widely used as the readout electronics in enzymatic electrochemical sensors. The integrated potentiostat with VACNF microelectrodes achieves competitive performance at low power and requires reduced chip space. Third, a low power instrumentation solution consisting of a programmable charge amplifier, an analog feature extractor and a control algorithm has been proposed and implemented to enable continuous physiological data extraction of bowel sounds using a single chip. Abdominal sounds can aid correlation of meal events to glucose levels. The developed integrated sensing systems represent a significant advancement in artificial pancreas systems

    READ-OUT CIRCUITS FOR INTEGRATED SURFACE ACOUSTIC WAVE SENSORS

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    Readout modules for vapor and liquid phase SAW sensors fabricated on piezoelectric films are typically configured as single or dual delay line oscillator loops. Mass loading of the sorbent film realized on the SAW device is detected as a frequency shift which is read externally via a frequency counter. However, this approach is not directly applicable in the development of a monolithically integrated autonomous sensor system suitable for wearable sensor tags and other field applications. In this work we have developed a data measurement topology suitable for monolithically integrated SAW sensors on CMOS chips, a technology that is not fully developed and will significantly increase Si-CMOS functionality. This readout technology achieves closed loop conversion of the SAW frequency response to a well-defined output voltage accurately tracking sensor behavior in real time. The topology is appropriate for thin film, low loss interdigitated (IDT) SAW devices used as mass loading sensors, such as those reported in [1] and [2]. The proposed closed loop system is controlled by a finite state machine (FSM) which forces the system output to oscillate within a narrow voltage range that correlates with the SAW pass-band response. The period of oscillation is of the order of the SAW phase delay. We also use timing information from the FSM to convert SAW phase delay to an on-chip 10 bit digital output operating on the principle of time to digital conversion (TDC). The output voltage range varies with changes in SAW center frequency, thus tracking mass sensing events in real time. This architecture precludes mode jumping issues found in designs incorporating the SAW delay line or the resonator in the feedback loop of an amplifier. It was demonstrated that the system can be adapted to alternate SAW center frequencies and group delays by adjusting the VCO control and TDC delay control inputs. Because of frequency to voltage and phase to digital conversion, this topology does not require external frequency counter setups and is uniquely suitable for full monolithic integration of autonomous sensor systems and tags

    Ionic and Osmotic Mechanisms Of Insect Chill-Coma And Chilling Injury

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    A mechanistic understanding of how temperature limits insect performance is needed to accurately model insect distribution and abundance. Upon crossing the temperature of their critical thermal minimum (CTmin), insects enter a state of paralysis (chill-coma). Chill-susceptible insects accumulate injuries (termed chilling injury) during prolonged exposure to low temperatures. My objective was to determine the mechanisms by which both chill-coma and chilling injury manifest in chill-susceptible insects. In aquatic animals, critical thermal limits are associated with a temperature-induced failure of oxygen supply relative to demand (oxygen- and capacity- limitation of thermotolerance; OCLT), which leads to reliance on anaerobic metabolism at thermal extremes. However, using open-flow respirometry and biochemical techniques, I found that fall field crickets (Gryllus pennsylvanicus) in chill-coma continued to exchange gases through the tracheal system and did not accumulate anaerobic byproducts, which suggests OCLT does not set the CTmin of insects. To characterize the patterns of ion balance disruption at low temperatures, I estimated water and ion content of the hemolymph and tissues of G. pennsylvanicus in chill-coma using gravimetric methods and atomic absorption spectrometry. Exposure to low temperatures caused a movement of Na+ and water from the hemolymph to the gut in G. pennsylvanicus, which increased hemolymph [K+] and depolarized muscle resting potential. When removed from the cold, crickets rebalanced ions and water, and the restoration of hemolymph [K+] (and muscle equilibrium potential) was coincident with the recovery of neuromuscular function. Although crickets recover the ability to move rapidly after removal from the cold, complete recovery of ion and water homeostasis requires additional time and metabolic investment. There is both inter- and intraspecific variation in cold tolerance in flies of the genus Drosophila. Using ion-selective microelectrodes, I found that cold-tolerant Drosophila species and cold- acclimated D. melanogaster maintain low concentrations of [Na+] and [K+] in their hemolymph. Drosophila cold tolerance was also associated with low Na+/K+-ATPase activity on a whole-organism level. Together, these studies allow me to construct a conceptual model of how the direct effects of temperature on ion homeostasis may drive chill-coma, chill-coma recovery and chilling injury in insects
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