The turnover and distribution of labelled corticosterone during post-natal development of the duckling (Anas platyrhynchos)

During 6 months of post-natal development in the laboratory, the weight of the adrenal gland relative to body weight decreases exponentially. In the 3 day-old duckling a single intravenous dose of labelled corticosterone becomes distributed in a very large apparent volume and an "extracellular" pool that is greater than the extracellular fluid volume and the pattern of disappearance of labelled hormone from plasma is biphasic. Later during development the volumes of distribution decrease and the biphasic pattern of disappearance becomes less distinct until at 6 months only one phase of disappearance can be detected with confidence. No significant change in plasma corticosterone concentration occurs during this period of development in the laboratory. Estimations of the corticosterone secretory rates, however, indicate that whereas the adrenal weight-specific rate os secretion increases during the first 3 weeks and declines therafter, the bodyf weight-specific secretory rate continues to decline throughtout the period of increasing body weight.     

Piezoelectric paint: Ceramic-polymer composites for vibration sensors

A piezoelectric ceramic-polymer composite has been developed for use as a novel thick film strain sensor for vibration monitoring of structures. The material is in the form of a paint that can be applied to a wide range of substrates using conventional spraying equipment. The sensor properties depend on the morphology of the composite and on the electrodes that are used to couple it to the charge amplifier. Electrodes of various kinds have been tested. Interaction between the electrode and the piezoelectric paint sometimes occurs (for example, the organic vehicle for spray-coated electrodes may interact with the paint binder). The morphologies of the piezoelectric paint and of the electrode materials have been studied using light optical microscopy and scanning electron microscopy to investigate the effect of different compositions and of different processing conditions (e.g., paint mixing schedule). Preliminary work is reported on the characteristics of the piezoelectric particles and on the effect of heat treatment applied to anneal out defects produced by milling. X-ray analysis and particle size analysis have been used to characterize the changes that take place on heat treatment. X-ray diffractometry has also been used to follow the effect of poling on the paint sensors. At the present state of development, sensors made using the paint have a dynamic range of at least 40–4000 microstrain and a bandwidth of at least 1 Hz–2 kHz, and piezoelectric coefficient d ₃₁ of approximately 20 pC/N. The sensors are resistant to outdoor exposure and a successful field trial has been conducted.     

Reward,persuasion, and the Sokal Hoax: A study in citation identities

A citation identity is a list of an author's citees ranked by how frequently that author has cited them in publications covered by the Institute for Scientific Information. The same Dialog software that creates identities can simultaneously show the overall citation counts of citees, which indicate their reputations. Using identities for 28 authors in several disciplines of science and scholarship, I show that the reputational counts of their citees always have an approximately log-normal distribution: citations to very famous names are roughly balanced by citations to obscure ones, and most citations go to authors of middling reputation. These results undercut claims by constructivists that the main function of citation is to marshal “big-name” support for arguments at the expense of crediting lesser-known figures. The results are better explained by Robert K. Merton's norm of universalism, which holds that citers are rewarding use of relevant intellectual property, than by the constructivists' particularism, which holds that citers are trying to persuade through manipulative rhetoric. A universalistic citation pattern appears even in Alan Sokal's famous hoax article, where some of his citing was deliberately particularistic. In fact, Sokal's basic adherence to universalism probably helped his hoax succeed, which suggests the strength of the Mertonian norm. In specimen cases, the constructivists themselves are shown as conforming to it. This revised version was published online in June 2006 with corrections to the Cover Date.     

Low linolenate and commercial soybean oils diminish serum HDL cholesterol in young free-living adult females

OBJECTIVE: A mutant soybean line (A16) low in linolenic acid content (2% of oil by weight) was developed to increase oil oxidative stability. It was unknown whether serum lipid and lipoprotein concentrations in humans would be affected should A16 soybean oil (A16 oil) replace commercial soybean oil in diets. This study was conducted to examine the hypothesis that in free-living normolipidemic women, the consumption of A16 oil at approximately 10% of energy intake (en%) would not affect serum lipids and lipoproteins differently than would the consumption of the same amount of a commercial soybean oil with 7% of linolenic acid content. DESIGN: Fifteen free-living female college students consumed the soybean oil daily with regular meals for 9 weeks in different orders, with each test oil being eaten for 3 weeks. During the study, 13 en% was provided by each test oil and a total of 35 en% was from dietary fat. Serum concentrations of total cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), low-density lipoprotein cholesterol (LDL cholesterol) and triacylglycerides (TAG) were measured. Serum total fatty acid patterns were analyzed as well. RESULTS: Each of the three test oils decreased serum total cholesterol, LDL cholesterol and TAG concentrations from the baseline values. The feeding of A16 and commercial soybean oils decreased serum HDL cholesterol significantly compared with coconut oil (p < 0.05). Dietary inclusion of coconut oil increased serum myristic acid significantly more than did either soybean oil (p < 0.01). Serum arachidonic acid concentrations were significantly greater with A16 consumption than with commercial soybean oil consumption (p < 0.001). CONCLUSION: A16 and commercial soybean oils both diminished serum HDL cholesterol. Although the fatty acid composition differed between the two soybean oils, A16 oil and commercial oil had similar effects on serum concentrations of lipoproteins and lipids. With increased oxidative stability, A16 oil is a good alternative to commercial soybean oil.     

Nanoparticle-functionalized porous polymer monolith detection elements for surface-enhanced Raman scattering

The use of porous polymer monoliths functionalized with silver nanoparticles is introduced in this work for high-sensitivity surface-enhanced Raman scattering (SERS) detection. Preparation of the SERS detection elements is a simple process comprising the synthesis of a discrete polymer monolith section within a silica capillary, followed by physically trapping silver nanoparticle aggregates within the monolith matrix. A SERS detection limit of 220 fmol for Rhodamine 6G is demonstrated, with excellent signal stability over a 24 h period. The capability of the SERS-active monolith for label-free detection of biomolecules was demonstrated by measurements of bradykinin and cytochrome c. The SERS-active monoliths can be readily integrated into miniaturized micrototal-analysis systems for online and label-free detection for a variety of biosensing, bioanalytical, and biomedical applications.     

Dynamic Force Measurement at the Microgram Level, with Application to Myofibrils of Striated Muscle

We describe a system for measurement of the dynamic mechanical properties of small bundles of myofibrils of muscle. Underwater fiber-optic sensing of tension via displacement of a quartz beam has been accomplished with a noise level of about 100 nanoNewtons in a bandwidth of 1 to 40 Hz.     

Immobilisation of α-Amylase on Polyaromatic and Titanium Compounds Incorporating a Magnetic Material

Three methods of preparing immobilised α-amylase on supports which incorporate magnetic properties have been developed. The use of diazotized 1,3-diaminobenzene coated on magnetic iron oxide, which was itself either uncoated or coated with hydrous titanium (IV) oxide, was found to result in higher bound activities of the immobilised enzyme. The immobilised enzyme prepared from diazotized 1,3-diaminobenzene coated magnetic iron oxide support showed excellent stability towards freeze drying. A preparation of immobilised enzyme using magnetic iron coated with hydrous titanium (IV) oxide resulted in a greater thermostability. This support can be prepared in situ, overcoming the problem of loss of activity of the freeze dried immobilised enzyme.     

Low loss mirrors for InP/InGaAsP waveguides

The loss associated with a mirror in an InP-based waveguide has been investigated. Mirror roughness and non-verticality were both significant sources of loss. Mirrors with only 1 dB loss have been produced through novel fabrication techniques.<>     

Picosecond pulse generation with ultralow jitter in 1.5-μmmulticontact MQW lasers using Q-switching

High-peak-power picosecond pulses with ultralow jitter of 65 fs (50-500 Hz) have been generated by Q-switching multi-quantum-well (MQW) distributed-feedback (DFB) and Fabry-Perot (FP) multicontact lasers. Peak pulse powers of 80 mW have been measured for pulses having durations of 26 ps and repetition rates of 1.25 GHz