Vacuum-Packaged Suspended Microchannel Resonant Mass Sensor for Biomolecular Detection

There is a great need in experimental biology for tools to study interactions between biological molecules and to profile expression levels of large numbers of proteins. This paper describes the fabrication, packaging and testing of a resonant mass sensor for the detection of biomolecules in a microfluidic format. The transducer employs a suspended microchannel as the resonating element, thereby avoiding the problems of damping and viscous drag that normally degrade the sensitivity of resonant sensors in liquid. Our device differs from a vibrating tube densitometer in that the channel is very thin, which enables the detection of molecules that bind to the channel walls; this provides a path to specificity via molecular recognition by immobilized receptors. The fabrication is based on a sacrificial polysilicon process with low-stress low-pressure chemical-vapor deposited (LPCVD) silicon nitride as the structural material, and the resonator is vacuum packaged on the wafer scale using glass frit bonding. Packaged resonators exhibit a sensitivity of 0.8 ppm/(ngmiddotcm²) and a mechanical quality factor of up to 700. To the best of our knowledge, this quality factor is among the highest so far reported for resonant sensors with comparable surface mass sensitivity in liquid     

Non-isothermal dyeing of wool

Kinetic models of the dyeing process are reviewed and diffusion of dye into the fibre is identified as the rate-determining step in most dyeing processes. A simpler approach to defining a linear exhaustion profile of acid dyes on wool fibres is proposed that takes into account non-isothermal kinetic models and analyses their possibilities of use. In this endeavour a novel dyeing rate constant is defined that appears to be characteristic of a particular dye class.     

Design and optimisation of a combination solar collector–thermal engine operating on Mars

A “dynamic” solar power plant (which consists of a solar collector–thermal engine combination) is proposed as an alternative for the more usual photovoltaic cells. A model for heat losses in a selective flat-plate solar collector operating on Mars is developed. An endoreversible Carnot cycle is used to describe heat engine operation. This provides upper limits for real performances. The output power is maximized. Meteorological and actinometric data provided by Viking Landers are used as inputs. Two strategies of collecting solar energy were considered: (i) horizontal collector; (ii) collector tilt and orientation are continuously adjusted to keep the receiving surface perpendicular on the Sun’s rays. The influences of climate and of various design parameters on solar collector heat losses, on engine output power and on the optimum sun-to-user efficiency are discussed.     

Electrical Resistance Noise and Thermal Fluctuation in High-Tc Granular Superconductors

Measurements of the electrical resistance and noise in YBCO high-T _c granular superconductors show that the separation between the noise peak, which is near the zero-resistance temperature, and the maximum of the |dR/dT| from the high temperatures, increases with the magnetic field. In a variable magnetic field, the separation between the peak in the noise and the peak in |dR/dH| increases with the temperature. The thermal fluctuations are enhanced by a high applied magnetic field and by a high temperature. In the low-temperature part of the superconducting transition, there are oscillations of the thermal fluctuations whose peaks are increased toward high temperatures. The range between the successive peaks of |dR/dT| is decreased at high temperatures because the number of the vortex lines within the vortex bundles is diminished.     

Sum capacity and TSC bounds in collaborative multibase wireless systems

We consider a wireless system with base stations which collaborate, and derive bounds on sum capacity and total squared correlation for uniform channels between users and bases. The correspondence also investigates structural properties which must be satisfied by user transmit covariance matrices at the optimal sum capacity/total squared correlation (TSC) point, and shows that for multibase systems, maximizing sum capacity and minimizing TSC are, in general, not equivalent problems.     

Structure and transcriptional regulation of the human mammaglobin gene, a breast cancer associated member of the uteroglobin gene family localized to chromosome 11q13

This research describes the development of the Marital Self-Disclosure Questionnaire (MSDQ), a brief, self-report measure of the quantity and quality of marital self-disclosure. Consisting of 40 true-false items, the MSDQ provides a global index of marital self-disclosure as well as assesses four facets of self-disclosure between spouses: Relationship, Sex, Money, and Imbalance. Results indicate that the MSDQ scales are reliable, and preliminary data suggest that the MSDQ may have validity for distinguishing among groups hypothesized to differ in terms of marital distress and self-disclosure. Further evaluation of the MSDQ for its clinical and research utility appears to be warranted.     

Althesin (alphadione, CT 1341) a 'new' induction agent for anesthesia

Althesin (alphadione) is a hypnotic agent introduced in the U.K. a few years ago by the firm of Glaxo. It is mixture of two steroids: alphaxalone 9 mg per ml and alphadolone 3 mg per ml, in solution in cremophore EL. After a concise review of the history of steroid anesthetics, the pharmacology of the new product is described. In a personal investigation, Althesin was used to induce anesthesia in 100 patients. The dose equivalent with thiopentone was determined first. It was found to amount to 52 microliter per kg corresponding to 3 mg per kg of thiopentone. A separate form was completed for each individual patient, to record the side effects, if any. The pulse and blood pressure were checked once a minute after the induction (for 5 minutes). In 8 patients the following parameters were recorded: plethysmogram, ECG, central venous pressure, pulse rhythm arterial pressure, stroke volume and cardiac output. Compared with thiopentone, Althesin is not significantly worse, but neither does it present any advantages where the circulatory parameters determined are concerned. In view of this and the recent publication concerning hypersensitivity reactions, we have ceased to use this hypnotic agent in our department.     

Blind removal of lens distortion

Virtually all imaging devices introduce some amount of geometric lens distortion. A technique is presented for blindly removing these distortions in the absence of any calibration information or explicit knowledge of the imaging device. The basic approach exploits the fact that lens distortion introduces specific higher-order correlations in the frequency domain. These correlations can be detected by using tools from polyspectral analysis. The amount of distortion is then estimated by minimizing these correlations.