170 research outputs found

    Ligand-Based Regulation of Dynamics and Reactivity of Hemoproteins

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    Hemoproteins include several heme-binding proteins with distinct structure and function. The presence of the heme group confers specific reactivity and spectroscopic properties to hemoproteins. In this review, we provide an overview of five families of hemoproteins in terms of dynamics and reactivity. First, we describe how ligands modulate cooperativity and reactivity in globins, such as myoglobin and hemoglobin. Second, we move on to another family of hemoproteins devoted to electron transport, such as cytochromes. Later, we consider heme-based reactivity in hemopexin, the main heme-scavenging protein. Then, we focus on heme-albumin, a chronosteric hemoprotein with peculiar spectroscopic and enzymatic properties. Eventually, we analyze the reactivity and dynamics of the most recently discovered family of hemoproteins, i.e., nitrobindins

    Validation of the Mini Nutritional Assessment-Short Form in a population of frail elders without disability. Analysis of the Toulouse Frailty Platform population in 2013

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    **Objective** To assess the validity of the Mini Nutritional Assessment-Short Form (MNA-SF) in elderly patients from the Toulouse Frailty Platform. **Participants** Overall, 267 patients aged 65 and over, without severe cognitive impairment (i.e. Mini Mental Status Examination > 20 and CDR<1), no physical disability (i.e. Activities of Daily Living ≥ 5) and no active cancer history (over the past 12 months) were included in 2013. **Measurements** Receiver operating characteristic (ROC) analyses were used to assess the predictive validity of the French version of the MNA-SF for good nutritional status (defined as a full MNA score≥24/30). Analyses were conducted in the overall sample and then in subgroups of frail and pre-frail subjects according to the frailty phenotype. Optimal cut-off points were determined to obtain the best sensitivity/specificity ratio and the highest number of correctly classified subjects. **Results** Among 267 patients, mean age=81.5±5.8; women=67.0%; 138 (51.7%) were frail, 98 (36.7%) were pre-frail and 31 (11.6%) were robust. Given their MNA-SF scores, 201 (75.3%) had a good nutritional status, 61 (22.8%) were at risk of malnutrition and 5 (1.9%) were malnourished. In the overall sample, but also in subgroups of pre-frail or frail elders, the areas under ROC curves were 0.954, 0.948 and 0.958 respectively. The 11 points cut-off provided the best correct classification ratio (91.4%); sensitivity=94.0%, specificity=83.3%. **Conclusion** The MNA-SF appeared to be a validated and effective tool for malnutrition screening in frail elders. Implementing this tool in clinical routine should contribute to improving the screening of malnourished frail individuals

    Neurodevelopmental risk factors in schizophrenia

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    The authors review environmental and neurodevelopmental risk factors for schizophrenic disorders, with emphasis on minor physical anomalies, particularly craniofacial anomalies and dermatoglyphic variations. The high prevalence of these anomalies among schizophrenic subjects supports the neurodevelopmental theory of the etiology of schizophrenia, since they suggest either genetically or epigenetically controlled faulty embryonic development of structures of ectodermal origin like brain and skin. This may disturb neurodevelopment that in turn may cause these subjects to be at increased risk for the development of schizophrenia and related disorders. The precise confirmation of this theory, at least in some cases, will provide further understanding of these illnesses, allowing easy and inexpensive identification of subjects at risk and providing guidelines for the development of new pharmacological interventions for early treatment and even for primary prevention of the illness

    Event-related potential studies of post-traumatic stress disorder: a critical review and synthesis

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    Despite the sparseness of the currently available data, there is accumulating evidence of information processing impairment in post-traumatic stress disorder (PTSD). Studies of event-related potentials (ERPs) are the main tool in real time examination of information processing. In this paper, we sought to critically review the ERP evidence of information processing abnormalities in patients with PTSD. We also examined the evidence supporting the existence of a relationship between ERP abnormalities and symptom profiles or severity in PTSD patients. An extensive Medline search was performed. Keywords included PTSD or post-traumatic stress disorder, electrophysiology or EEG, electrophysiology, P50, P100, N100, P2, P200, P3, P300, sensory gating, CNV (contingent negative variation) and MMN (mismatch negativity). We limited the review to ERP adult human studies with control groups which were reported in the English language. After applying our inclusion-exclusion review criteria, 36 studies were included. Subjects exposed to wide ranges of military and civilian traumas were studied in these reports. Presented stimuli were both auditory and visual. The most widely studied components included P300, P50 gating, N100 and P200. Most of the studies reported increased P300 response to trauma-related stimuli in PTSD patients. A smaller group of studies reported dampening of responses or no change in responses to trauma-related and/or unrelated stimuli. P50 studies were strongly suggestive of impaired gating in patients with PTSD. In conclusion, the majority of reports support evidence of information processing abnormalities in patients with PTSD diagnosis. The predominance of evidence suggests presence of mid-latency and late ERP components differences in PTSD patients in comparison to healthy controls. Heterogeneity of assessment methods used contributes to difficulties in reaching firm conclusions regarding the nature of these differences. We suggest that future ERP-PTSD studies utilize standardized assessment scales that provide detailed information regarding the symptom clusters and the degree of symptom severity. This would allow assessment of electrophysiological indices-clinical symptoms relationships. Based on the available data, we suggest that ERP abnormalities in PTSD are possibly affected by the level of illness severity. If supported by future research, ERP studies may be used for both initial assessment and treatment follow-up

    Alumina Femoral Head Fracture: An in Vitro Study

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    A fracture of a ceramic femoral head is reported in this study. Fractures of ceramic femoral heads are uncommon and reports on this complication are rare. After 3 million cycles, on a twelve station hip simulator that tested alumina femoral head against polyethylene acetabular cup, fracture of the ceramic ball was observed. The retrieved specimen consisted of three large ceramic fragments from the same ceramic femoral head, a polyethylene acetabular cup and a stainless steel jig. Careful and detailed examination of the removed components was made. The fracture of the ceramic ball resulted in damage to the metal taper of the jig component which was fixed into the simulator.</jats:p

    Clinical peri-implant sounding accuracy in the presence of chronic inflammation of peri-implant tissues. Clinical observation study

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    AIM: The aim of this study was to assess if the probing pocket depth is a reliable clinical parameter in the evaluation of the depth of the peri-implant sulci. In case of chronic inflamed peri-implant tissues, this evaluation is useful for understanding the level of bone resorption. METHODS: The study enrolled 22 patients. All of them were diagnosed for a peri-implantitis and were scheduled for a resective surgery with implantoplasty. During the surgery, a full thickness flap was raised and resective surgery was performed as well as an implantoplasty procedure. Peri-implant probing values before the surgery (PAL) were recorded, as were values of bone resorption after flap elevation (DIB), at all four sites around each implant (88 sites). RESULTS: The mean value of PAL calculated for all 88 sites was 5.67 mm (+/-1.46); the correspondent value of DIB was 6.37 mm (+/-1.81). In 52 sites out of 88 (59.1%) the values of PAL and DIB were exactly the same (maximum difference 0.5 mm). In only 10 cases (11.3%) the difference between PAL and DIB was >2 mm. The mean values for PAL and DIB were not statistically different. CONCLUSIONS: Authors have concluded that in case of chronic inflammation of peri-implant tissues, the probe reaches the bone pick, allowing the clinician to have reliable information on the actual bone resorptio

    A soft magnetic material for power supply systems of high energy physics experiments

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    Most of the high energy physics experiments require their detectors to be embedded in a high intensity magnetic field. In particular the biggest of them, ATLAS, running in the CERN Large Hadron Collider (LHC) particle accelerator, generates a field of 2 T by means of a gigantic toroidal magnet working in open air. Its future phase 2 upgrade plans to move the DC/DC power supplies from the present positions on the external balconies directly on the detectors, where the field is of the order of 1 T. This presentation describes the development of samples made of special magnetic material for inductor cores suitable to work in such an environment. Starting from iron-silicon powders, at FN plant a plastic forming process, based on powder extrusion, injection moulding and sintering, was developed. To get the best compromise between the forming process requirements (good coupling among the metallic powder and the organic components to assure the right mouldability) and the debinding and sintering conditions, several mixtures (with different percentages and kind of organic additives) were experimented. A proper mould was designed and realized to get torous-shaped prototypes. The preliminary results of the physical-microstructural characterization performed on the first prototypes made will be shown
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