Medical

Real-Time, High-Frequency QRS Electrocardiograph

Signals indicative of ischemia or infarction can be identified in real time. An electronic system that performs real-time analysis of the low-amplitude, high-frequency, ordinarily invisible components of the QRS portion of an electrocardiographic signal in real time has been developed. Whereas the signals readily visible on a conventional electrocardiogram (ECG) have amplitudes of the order of a millivolt and are characterized by frequencies

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Time-Resolved Measurements in Optoelectronic Microbioanalysis

A report presents discussion of time-resolved measurements in optoelectronic microbioanalysis. Proposed microbioanalytical "laboratory-on-a-chip" devices for detection of microbes and toxic chemicals would include optoelectronic sensors and associated electronic circuits that would look for fluorescence or phosphorescence signatures of multiple hazardous biomolecules in order to detect which ones were present in a given situation. The emphasis in the instant report is on gating an active-pixel sensor in the time domain, instead of filtering light in the wavelength domain, to prevent the sensor from responding to a laser pulse used to excite fluorescence or phosphorescence while enabling the sensor to respond to the decaying fluorescence or phosphorescence signal that follows the laser pulse. The active-pixel sensor would be turned on after the laser pulse and would be used to either integrate the fluorescence or phosphorescence signal over several lifetimes and many excitation pulses or else take time-resolved measurements of the fluorescence or phosphorescence. The report also discusses issues of multiplexing and of using time-resolved measurements of fluorophores with known different fluorescence lifetimes to distinguish among them.

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Growth Conditions To Reduce Oxalic Acid Content of Spinach

A controlled environment agricultural (CEA) technique to increase the nutritive value of spinach has been developed. This technique makes it possible to reduce the concentration of oxalic acid in spinach leaves. It is desirable to reduce the oxalic acid content because oxalic acid acts as an anti-nutritive calcium-binding component. More than 30 years ago, an enzyme (an oxidase) that breaks down oxalic acid into CO2 and H2O2 was discovered and found to be naturally present in spinach leaves. However, nitrate, which can also be present because of the use of common nitrate-based fertilizers, inactivates the enzyme. In the CEA technique, one cuts off the supply of nitrate and keeps the spinach plants cool while providing sufficient oxygen. This technique provides the precise environment that enables the enzyme to naturally break down oxalate. The result of application of this technique is that the oxalate content is reduced by 2/3 in one week.

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Hydrofocusing Bioreactor for Three-Dimensional Cell Culture

Hydrofocusing reduces shear while "herding" cells and air bubbles. The hydrodynamic focusing bioreactor (HFB) is a bioreactor system designed for three-dimensional cell culture and tissue-engineering investigations on orbiting spacecraft and in laboratories on Earth. The HFB offers a unique hydrofocusing capability that enables the creation of a low-shear culture environment simultaneously with the "herding" of suspended cells, tissue assemblies, and air bubbles. Under development for use in the Biotechnology Facility on the International Space Station, the HFB has successfully grown large three-dimensional, tissue-like assemblies from anchorage-dependent cells and grown suspension hybridoma cells to high densities.

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Simulating an Arthroscopic Surgical Instrument

CAD and finite element analysis software help verify the design of a temperature control electrode. Sports-related injuries are a common cause of damaged ligaments and tendons in shoulders, knees, wrists, elbows and ankles, and can usually be repaired through arthroscopic surgery. Through an incision no larger than a keyhole, a surgeon inserts an endoscope to see inside the joint on a video monitor during the operation. Arthroscopic surgery significantly reduces the disturbance and traumatization to the joint as compared to conventional surgery, thus minimizing the amount of invasion, discomfort, scarring, and recovery time.

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Quantitating Iron in Serum Ferritin by Use of ICP-MS

Ferritin associated with inflammation can be distinguished from ferritin associated with hemochromatosis. A laboratory method has been devised to enable measurement of the concentration of iron bound in ferritin from small samples of blood (serum). Derived partly from a prior method that depends on large samples of blood, this method involves the use of an inductively coupled plasma mass spectrometer (ICP-MS).

Posted in: Bio-Medical, Medical, Briefs, TSP

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Semiselective Optoelectronic Sensors for Monitoring Microbes

These real-time sensors distinguish among classes (not individual species) of microbes. Sensor systems are under development for use in real-time detection and quantitation of microbes in water without need for sampling. These systems include arrays of optical sensors; miniature, portable electronic data-acquisition circuits; and optoelectronic interfaces between the sensor arrays and data-acquisition circuits. These systems are intended for original use in long-term, in-line monitoring of waterborne micro-organisms in water-reclamation systems aboard future spacecraft. They could also be adapted to similar terrestrial uses with respect to municipal water supplies, stored drinking water, and swimming water; for detecting low-level biological contamination in biotechnological, semiconductor, and pharmaceutical process streams; and in verifying the safety of foods and beverages. In addition, they could be adapted to monitoring of airborne microbes and of surfaces (e.g., to detect and/or quantitate biofilms).

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