1,278 research outputs found

    Compression modes in nuclei: microscopic models with Skyrme interactions

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    The isoscalar giant monopole resonances (ISGMR) and giant dipole resonances (ISGDR) in medium-heavy nuclei are investigated in the framework of HF+RPA and HF-BCS+QRPA with Skyrme effective interactions. It is found that pairing has little effect on these modes. It is also found that the coupling of the RPA states to 2p-2h configurations results in about (or less than) 1 MeV shifts of the resonance energies and at the same time gives the correct total widths. For the ISGMR, comparison with recent data leads to a value of nuclear matter compression modulus close to 215 MeV. However, a discrepancy between calculated and measured energies of the ISGDR in 208^{208}Pb is found and remains an open problem.Comment: To appear in: ``RIKEN Symposium and Workshop on Selected Topics in Nuclear Collective Excitations'', proceedings of the meeting, RIKEN, Wako city (Japan), March 20--24, 199

    Holistic engineering of Cal-A lipase chain-length selectivity identifies triglyceride binding hot-spot

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    Through the application of a region-focused saturation mutagenesis and randomization approach, protein engineering of the Cal-A enzyme was undertaken with the goal of conferring new triglyceride selectivity. Little is known about the mode of triglyceride binding to Cal-A. Engineering Cal-A thus requires a systemic approach. Targeted and randomized Cal-A libraries were created, recombined using the Golden Gate approach and screened to detect variants able to discriminate between long-chain (olive oil) and short-chain (tributyrin) triglyceride substrates using a high-throughput in vivo method to visualize hydrolytic activity. Discriminative variants were analyzed using an in-house script to identify predominant substitutions. This approach allowed identification of variants that exhibit strong discrimination for the hydrolysis of short-chain triglycerides and others that discriminate towards hydrolysis of long-chain triglycerides. A clear pattern emerged from the discriminative variants, identifying the 217–245 helix-loop-helix motif as being a hot-spot for triglyceride recognition. This was the consequence of introducing the entire mutational load in selected regions, without putting a strain on distal parts of the protein. Our results improve our understanding of the Cal-A lipase mode of action and selectivity. This holistic perspective to protein engineering, where parts of the gene are individually mutated and the impact evaluated in the context of the whole protein, can be applied to any protein scaffold

    Common variable immunodeficiency disorder (CVID)-related liver disease: assessment of the main histological aspects using novel semiquantitative scoring systems, image analysis and correlation with clinical parameters of liver stiffness and portal hypertension

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    Aims: We aimed to investigate the relationship between T-cell-mediated sinusoidal injury, nodular regenerative hyperplasia like changes (NRH-LC) and fibrosis, clinical measures of fibrosis and portal hypertension, and progression rate in common variable immunodeficiency disorder (CVID)-related liver disease. / Methods: This is a retrospective single-centre study. Liver biopsies from CVID patients with liver disease were reviewed to assess for NRH-LC, fibrosis and elastosis, including collagen and elastin proportionate areas. CD3 positive T-cells infiltration and sinusoidal endothelial changes by CD34 expression were quantified by image analysis and a semiquantitative method, respectively. These findings were correlated with liver stiffness measurements (LSM) and hepatic venous pressure gradient (HVPG). / Results: NRH-LC and pericellular elastosis were present in most biopsies (32/40 and 38/40, respectively). All biopsies showed fibrosis, which was limited to pericellular in 21/40 (52.5%) and included bridging fibrous septa in 19/40 (47.5%). 28/40 liver biopsies showed enhanced sinusoidal expression of CD34. There were more CD3 positive cells in biopsies with NRH-LC compared with those without. There was no significant correlation between LSM, HVPG and fibrosis/elastosis scores. Five of seven patients with at least two biopsies showed progression in fibrosis stage. / Conclusions: NRH-LC and fibrosis in CVID patients often coexist along with the presence of sinusoidal endothelial changes and sinusoidal lymphocytic infiltration. Fibrosis progresses over time, and significant fibrosis can be observed in young patients (<30 years old), potentially reflecting a more aggressive form of CVID-related liver disease. Further studies are necessary to investigate the relationship between histological findings, clinical measures of fibrosis and portal hypertension and outcome

    Systematic review of the role of high intensity focused ultrasound (HIFU) in treating malignant lesions of the hepatobiliary system

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    BACKGROUND: High Intensity Focused Ultrasound (HIFU) is an emerging non-invasive, targeted treatment of malignancy. The aim of this review was to assess the efficacy, safety and optimal technical parameters of HIFU to treat malignant lesions of the hepatobiliary system. METHODS: A systematic search of the English literature was performed until March 2020, interrogating Pubmed, Embase and Cochrane Library databases. The following key-words were input in various combinations: 'HIFU', 'High intensity focussed ultrasound', 'Hepatobiliary', 'Liver', 'Cancer' and 'Carcinoma'. Extracted content included: Application type, Exposure parameters, Patient demographics, and Treatment outcomes. RESULTS: Twenty-four articles reported on the clinical use of HIFU in 940 individuals to treat malignant liver lesions. Twenty-one studies detailed the use of HIFU to treat hepatocellular carcinoma only. Mean tumour size was 5.1 cm. Across all studies, HIFU resulted in complete tumour ablation in 55% of patients. Data on technical parameters and the procedural structure was very heterogeneous. Ten studies (n = 537 (57%) patients) described the use of HIFU alongside other modalities including TACE, RFA and PEI; 66% of which resulted in complete tumour ablation. Most common complications were skin burns (15%), local pain (5%) and fever (2%). CONCLUSION: HIFU has demonstrated benefit as a treatment modality for malignant lesions of the hepatobiliary system. Combining HIFU with other ablative therapies, particularly TACE, increases the efficacy without increasing complications. Future human clinical studies are required to determine the optimal treatment parameters, better define outcomes and explore the risks and benefits of combination therapies

    A magnetic internal mechanism for precise orientation of the camera in wireless endoluminal applications

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    Background and study aims: The use of magnetic fields to control operative devices has been recently described in endoluminal and transluminal surgical applications. The exponential decrease of magnetic field strength with distance has major implications for precision of the remote control. We aimed to assess the feasibility and functionality of a novel wireless miniaturized mechanism, based on magnetic forces, for precise orientation of the camera. Materials and methods: A remotely controllable endoscopic capsule was developed as proof of concept. Two intracapsular moveable permanent magnets allow fine positioning, and an externally applied magnetic field permits gross movement and stabilization. Performance was assessed in ex vivo and in vivo bench tests, using porcine upper and lower gastrointestinal tracts. Results: Fine control of capsule navigation and rotation was achieved in all tests with an external magnet held steadily about 15 cm from the capsule. The camera could be rotated in steps of 1.8°. This was confirmed by ex vivo tests; the mechanism could adjust the capsule view at 40 different locations in a gastrointestinal tract phantom model. Full 360° viewing was possible in the gastric cavity, while the maximal steering in the colonwas 45° in total. In vivo, a similar performance was verified, where the mechanism was successfully operated every 5 cm for 40 cm in the colon, visually sweeping from side to side of the lumen; 360° views were obtained in the gastric fundus and body, while antrally the luminal walls prevented full rotation. Conclusions: We report the feasibility and effectiveness of the combined use of external static magnetic fields and internal actuation to move small permanent intracapsular magnets to achieve wirelessly controllable and precise camera steering. The concept is applicable to capsule endoscopy as to other instrumentation for laparoscopic, endoluminal, or transluminal procedures

    Food safety in collective catering: Knowledge, attitudes and correct application of GHP/GMP knowledge among foodservice workers

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    Food safety critically reliant on the behaviors adopted by foodservice personnel, involved in various stages of meal preparation, from the supply of raw food materials until its distribution to the consumer. The purpose of this work was to collect information on the level of knowledge on food safety, the correct application of the Good Hygiene Practices (GHP) and Good Manufacturing Practices (GMP) and the attitudes of the operators involved in collective catering. The survey was conducted among 15 social catering companies in Apulia (Italy) using a modified Sharif and Al-Malki (2010) anonymous questionnaire intended to assess the knowledge, attitudes and practices of the food handlers. The results highlight the need to improve both knowledge and practices regarding food hygiene and safety in order to minimize the risk of transmitting foodborne diseases. More careful planning, implementation, monitoring and evaluation of training programs for foodservice workers is required, taking into consideration the provisions of European food laws

    A 5-W GaN Doherty Amplifier for Ka-Band Satellite Downlink With 4-GHz Bandwidth and 17-dB NPR

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    This letter presents the design and experimental characterization of a GaN-Si monolithic Doherty power amplifier (PA) for the Ka-band satellite downlink. The fabricated amplifier favorably compares with the current state of the art, achieving from 16.3 to 20.3 GHz (4 GHz, 22% relative bandwidth), a record band to date, 36.6-37.7-dBm output power, 23%-31% power-added efficiency, 18-22-dB gain at saturation, and around 20% power-added efficiency at 6-dB output back-off. At 18.8 GHz, the amplifier shows a noise-to-power ratio higher than 17 dB at all power levels, making it suitable for satellite applications where additional linearization is usually unfeasible

    Trace Metals in Pork Meat Products Marketed in Italy: Occurrence and Health Risk Characterization

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    This study provides valuable information on the levels of various trace metals (Pb, Cd, Hg, Zn, Cu, Cr) in meat products (baked ham, raw ham, mortadella, cured sausage, würstel, salami) from South Italy and calculates potential health risk toxicity associated with their consumption for the total population and for children. In the samples studied metal concentrations are within the permissible legal limits (Cd: 0.01–0.03&nbsp;μg&nbsp;g−1 w.w., Hg: 0.01–0.02&nbsp;μg&nbsp;g−1 w.w., Zn: 5.71–7.32&nbsp;μg&nbsp;g−1 w.w., Cu: 1.08–1.21&nbsp;μg&nbsp;g−1 w.w., Cr: 0.15–0.23&nbsp;μg&nbsp;g−1 w.w.), except for Pb (Pb: 0.22–0.38&nbsp;μg&nbsp;g−1 w.w.). The estimated intake values are within the provisional tolerable daily intake limits for toxic metals and recommended daily intake values for essential metals in both tested groups. The noncarcinogenic risk values of the individual metals indicate that there is no health risk, but their combined effects might constitute a potential risk for children. Furthermore, the cumulative cancer risk of all samples studied exceeds the recommended threshold risk limit (&gt; 10−4) in both total population and children, indicating a risk of potential health problems for consumers especially for children, who are more vulnerable to toxic metal exposure

    Life-Threatening Cardiac Manifestations of Pheochromocytoma

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    Pheochromocytoma is a catecholamine-secreting tumor of the adrenal glands, usually with benign manifestations, whose typical clinical presentation includes the triad of headache, palpitations and diaphoresis. However, a wide range of signs and symptoms may be present. In the cardiovascular system, the most common signs are labile hypertension and sinus tachycardia. Systolic heart failure and ST-segment deviations mimicking myocardial infarction have also been reported, as well as QT interval prolongation and, rarely, ventricular tachycardia. We describe a challenging diagnosis of pheochromocytoma with many cardiovascular manifestations, which could have been missed due to the absence of typical symptoms
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