Efficacy of melatonin treatment in jet lag, shift work, and blindness

Melatonin has chronobiotic properties in humans. It is able to phase shift strongly endogenous rhythms, such as core temperature and its own endogenous rhythm, together with the sleep-wake cycle. Its ability to synchronize free-running rhythms has not been fully investigated in humans. There is evidence for synchronization of the sleep-wake cycle, but the available data suggest that it is less effective with regard to endogenous melatonin and core temperature rhythms. When suitably timed, most studies indicate that fast release preparations are able to hasten adaptation to phase shift in both field and simulation studies of jet lag and shift work. Both subjective and objective measures support this statement. However, not all studies have been successful. Careful evaluation of the effects on work-related performance is required. When used to alleviate the non-24-h sleep-wake disorder in blind subjects, again most studies report a successful outcome using behavioral measures, albeit in a small number of individuals. The present data suggest, however, that although sleep-wake can be stabilized to 24 h, entrainment of other rhythms is exceptionally rare.     

Measurement of the violation of the Madey theorem induced by a diverging wave

We have simultaneously measured the spectra of the gain and the forward spontaneous radiation in the Orsay free-electron laser so that we can extract the relative shift of these two curves. Our results are in agreement with the Madey theorem in the low divergence limit, and demonstrate the violation of the theorem produced as the Rayleigh range of the wave becomes comparable to or smaller than the length of the interaction region. We extend the single particle theory to account for the divergence of the wave to first order. The predictions from this linearized model are in reasonable agreement with the experimental results in view of the fundamental limitations on this kind of experiment.     

Electrically tuned spin-orbit interaction in an InAs self-assembled quantum dot

Electrical control over electron spin is a prerequisite for spintronics spin-based quantum information processing. In particular, control over the interaction between the orbital motion and the spin state of electrons would be valuable, because this interaction influences spin relaxation and dephasing. Electric fields have been used to tune the strength of the spin-orbit interaction in two-dimensional electron gases, but not, so far, in quantum dots. Here, we demonstrate that electrical gating can be used to vary the energy of the spin-orbit interaction in the range 50-150 μeV while maintaining the electron occupation of a single self-assembled InAs quantum dot. We determine the spin-orbit interaction energy by observing the splitting of Kondo effect features at high magnetic fields.     

Influence of Jet-Sploding and extrusion on ruminal and intestinal disappearance of canola and soybeans

In situ rumen degradation and intestinal digestibility of DM and CP of Jet-Sploded and extruded protein sources were estimated, using two ruminally and duodenally cannulated lactating Holstein cows, in two experiments. One-gram samples of ground (1 mm) whole canola seed, canola meal, extruded canola meal, Jet-Sploded whole canola seed, Protec, soybean meal and extruded soybean meal (Experiment 1), and whole canola seed Jet-Sploded at temperatures ranging from 116 to 177 degrees C (Experiment 2) were heat sealed into small nylon bags for incubation in the rumen and insertion into the duodenum. Extrusion had no effect on DM or CP disappearance in the rumen nor on effective degradability. Jet-Sploding of whole canola seed dramatically reduced effective degradability (%) of DM (80.5 vs 35.9 at .08 h-1 rumen outflow rate) and CP (83.5 vs. 43.2 at .08 h-1). Total tract disappearance of DM and CP exceeded 90% for all protein sources, except Protec and Jet-Sploded material. Jet-Sploding appears to have potential for decreasing ruminal degradation of canola protein or DM without markedly decreasing intestinal digestibility.     

Dunes, archaeology and the National Monuments Act

Dunes have often provided a focus for human settlement in the past. Traces of Stone Age camp sites can be found in consolidated and unconsolidated dune systems both along the South African coast and inland. Such sites are useful for dating dune systems as well as for providing palaeoenvironmental information. Examples from the Early, Middle and Late Pleistocene and the Holocene are given for illustration. The National Monuments Act protects all archaeological and palaeontological sites as they are part of the history of South Africa and are a non-renewable resource. A permit is required for excavating sites and for collecting fossils and artefacts.     

Coronal mode ultrasound guided hemodialysis cannulation: A pilot randomized comparison with standard cannulation technique

Background: Infiltrations from cannulation result in significant morbidity including loss of hemodialysis (HD) vascular access (VA). Cannulation is dependent on personnel skill and VA characteristics. Surface marking of VA lacks real‐time information and traditional ultrasound (US) devices are large, expensive, requiring skilled operators. Sonic Window© (Analogic Ultrasound, Peabody, MA, USA) is a coronal mode ultrasound device (CMUD) approved for VA cannulation. Methods: Single center randomized, prospective pilot study comparing handheld US‐guided cannulation of new arteriovenous fistula (AVF) to standard cannulation practices. Patients with end stage renal disease (ESRD) on in‐center HD who had a new AVF cleared for cannulation and dialysis were enrolled. Patients with new AVF received either standard cannulation (control group) or image guidance using CMUD (study group) for 3 weeks. Ultrasound characteristics of VA, cannulation practices and complications end points were obtained. Results: An infiltration rate of 9.7% was noted during the study. Slightly lower odds ratio (OR) of infiltration was observed in the study group (OR 0.94, 95% CI: 0.26–3.41, P value = 0.93). Study group yielded longer time for assessment (101.8 ± 80.2 vs. 22.3 ± 22.5 seconds, P = < 0.001), increased cannulation time (41.1 ± 70.6 vs. 25.0 ± 27.9 seconds, P = 0.04), and increased patient satisfaction (94.6% vs. 82%, P = 0.04) compared to control group. Number of cannulation attempts, needle size, arterial or venous needle insertion, and tourniquet usage between groups were not statistically different. Conclusion: Handheld ultrasound is a safe and useful aid in cannulation of dialysis access.