Spectral phase encoding for data storage and addressing

We propose to use a broad-bandwidth laser source for storing and retrieving multiple holograms in a photorefractive material. Each storage address is defined by a specific spectral encoding of the reference beam. The validity of the spectral encoding method is tested in a preliminary experiment

Red Spectral Forms of Chlorophylls in Green Plant PSI- A Site-Selective and High-Pressure Spectroscopy Study

One of the special spectroscopic characteristics of photosystem I (PSI) complexes is that they possess absorption and emission bands at lower energy than those of the reaction center. In this paper, the red pigment pools of PSI-200, PSI-core, and LHCI complex from Arabidopsis thaliana have been characterized at low temperatures by means of spectrally selective (hole-burning and fluorescence line-narrowing) and high-pressure spectroscopic techniques. It was shown that the green plant PSI-200 complex has at least three red pigment pools, from which two are located in the PSI-core and one, in the peripheral light-harvesting complex I (LHCI). All of the red pigment pools are characterized by strong electron-phonon coupling. A Huang-Rhys factor of 2.9 found for the red pigments of LHCI is the largest found for any photosynthetic antenna system. This contrasts with the bulk pigments in the main Qy absorption band of chlorophyll a pigments for which the Huang-Rhys factors of less than unity are observed. This electron-phonon coupling difference of the red and bulk pigments is well reflected by the spectral dependence of the hole-burning efficiency, which is significantly reduced in the red absorption region. As a result of extremely low hole-burning efficiency in the red absorption band of LHCI, the hole-burning spectra of the PSI-200 complex mainly originate from the red pigments of the PSI-core complex. At the same time, the source of the red emission in PSI-200 is the red pigments of LHCI, in agreement with previous studies. The hole-burning spectra of PSI-core complexes from green plant and cyanobacteria are similar, both in red and bulk absorption regions. High-pressure spectroscopy data reveal dramatically larger pressure-induced linear shift rates for the redmost absorption and emission bands relative to those of bulk absorption bands. This is interpreted as due mostly to increased conformational mixing between the locally excited and charge transfer configurations of the red pigment aggregates. On the basis of analysis of available experimental data, we suggest that pigment dimers are probably responsible for the redmost states. Consequently, the excited red states can be interpreted as excimer states

Buprenorphine for pain relief in mice: Repeated injections vs sustained-release depot formulation

Sustained-release formulations of analgesic drugs are promising alternatives to repeated drug injections. Here, we compared a sustained-release formulation of buprenorphine (SB, 2.2 mg/kg) with a standard protocol of three injections of buprenorphine (Temgesic, 0.1 mg/kg/8 h) in mice. Buprenorphine serum concentration and analgesic action (thermal sensitivity) were determined in healthy mice. Additionally, the pain relief properties of both protocols were assessed after laparotomy using physiological and ethological measures of pain and recovery. Serum concentrations and thermal sensitivity tests indicated duration of action of at least 4 h (but less than 8 h) with the Temgesic protocol, and 24-48 h with SB. Behavioural and clinical parameters indicated at least partial pain relief after surgery for both protocols. Observed side-effects of buprenorphine independent of the protocol were increased activity, disturbed circadian rhythm and several abnormal behaviours. A tendency for decreased food and water intake as well as body weight reduction was also seen. Body weight decreased significantly in animals that received three injections of Temgesic, regardless of whether surgery was performed or not (P = 0.015; P = 0.023), hinting at a stress response towards this repeated intervention. In conclusion, an application interval of 8 h (Temgesic) appears too long and might lead to repeated periods with insufficient analgesia in animals undergoing lasting and/or substantial pain after surgery. In comparison to the standard protocol, SB provided a long-lasting, assured analgesia without possible stressful repeated injections in a standard surgical model, with only limited and acceptable behavioural side-effects