Protein Phosphatase 1 (PP1) Is a Post-Translational Regulator of the Mammalian Circadian Clock

Circadian clocks coordinate the timing of important biological processes. Interconnected transcriptional and post-translational feedback loops based on a set of clock genes generate and maintain these rhythms with a period of about 24 hours. Many clock proteins undergo circadian cycles of post-translational modifications. Among these modifications, protein phosphorylation plays an important role in regulating activity, stability and intracellular localization of clock components. Several protein kinases were characterized as regulators of the circadian clock. However, the function of protein phosphatases, which balance phosphorylation events, in the mammalian clock mechanism is less well understood. Here, we identify protein phosphatase 1 (PP1) as regulator of period and light-induced resetting of the mammalian circadian clock. Down-regulation of PP1 activity in cells by RNA interference and in vivo by expression of a specific inhibitor in the brain of mice tended to lengthen circadian period. Moreover, reduction of PP1 activity in the brain altered light-mediated clock resetting behavior in mice, enhancing the phase shifts in either direction. At the molecular level, diminished PP1 activity increased nuclear accumulation of the clock component PER2 in neurons. Hence, PP1, may reduce PER2 phosphorylation thereby influencing nuclear localization of this protein. This may at least partially influence period and phase shifting properties of the mammalian circadian clock

Comparative investigation of methods to reduce truncation errors in partial spherical near-field antenna measurements

This paper presents a comparative investigation of two different but highly suitable techniques for the accurate determination of the full sphere pattern of an antenna from truncated spherical near field measurements. The first approach is based on an iterative procedure which exploits the band-limitedness properties of the radiated field to correctly reconstruct the full sphere data [1]. The second approach was first described in [2] and is based on determining a set of equivalent currents that radiate the same pattern in the known area and thus extrapolate the unknown fields in the truncated area. The comparative study is performed on actual measured near-field data to investigate the effectiveness of each technique in realistic spherical near field antenna measurement scenarios. © 2012 IEEE

Musculo-skeletal tumors incidence and surgical treatment – A single center 5-year retrospective

OBJECTIVE: Muscle-skeletal tumors represent a challenging pathology for orthopedic surgeons worldwide. The extremely invasive character, the local destruction, the high recurrence rate, the high incidence in young patients and the unfavorable prognosis are all very well known. For these patients it is very important to produce an accelerated functional, social and psychological postoperative rehabilitation. We studied 121 cases of muscle-skeletal tumors which were treated in our hospital over a 5 years period. PATIENTS AND METHODS: We noticed a high prevalence in males and mainly between the 2nd-3rd and 5th-7th decades of their life. At our observation, most patients were suffering in advanced stages of malignant lesions. RESULTS: We try to manage amputations below 5%, with a significant reduction in introducing reconstructive surgical methods as a choice of treatment (10 prostheses and 12 cases of filling with acrylic cement or bone substituent increased with internal fixation). In this way we could observe an unusual ratio between benign and malignant tumors, probably caused by the patient’s lack of concern for minimal symptoms. The rural citizen’s addressability towards the medical system is alarmingly low, due to the big gap existing from diagnosis to treatment. CONCLUSIONS: There is still an hard effort to develop better reconstructive techniques for the treatment of muscle-skeletal tumors and more studies must be made in order to achieve this goal