861 research outputs found
Chemical and oxygen isotopic composition of Roman and late Antique glass from northern Greece
The present paper emphasizes the importance of measuring the oxygen isotopic and chemical compositions of ancient glass, in
order to constrain some features such as age, raw materials, and production technologies and to identify the \u201cfingerprint\u201d of local
productions. In this context, thirty-nine Roman and late Antique glass samples and eight chert samples fromnorthern Greece were
selected and analysed for their oxygen isotopic and chemical compositions. Results show that the majority of glass samples are
produced using natron as flux and have 18O values of about 15.5\u2030, plus or minus a few tenths of one per mil, suggesting that raw
materials probably come from Levantine area. Four samples are heavily enriched in 18O, and their chemical composition clearly
shows that they were made with soda plant ash as flux. Isotopic and chemical data of Greek chert samples support the hypothesis
of local production of the above samples. About half of the glass samples have chemical compositions, which allow their age to be
constrained to the late Antique period. For the remaining glass, similarities with literature compositional groups are reported and
discussed
A novel combination of triple metachronous malignancies of the kidney, oropharynx and prostate. A case report
Synchronous or metachronous malignancies are a rare event, with an incidence rate that increases with age. The present study reports the case of a 70-year-old Caucasian male who was referred to the outpatient office of the Urology Unit, Sapienza University of Rome (Latina, Italy) due to lower urinary tract symptoms. An abdominal ultrasound investigation was performed that demonstrated the presence of a right renal mass. The patient underwent right radical nephrectomy, which resulted in the definitive diagnosis of clear cell type renal cell carcinoma. The patient was eventually diagnosed with triple primary metachronous cancer consisting of renal clear cell carcinoma, prostate adenocarcinoma and squamous cell carcinoma of the oropharynx (palatine tonsil). To the best of our knowledge, this combination of primary neoplasms has not previously been documented
Developments in Solid-State NMR Spectroscopy of Polymer Systems
Solid-state nuclear magnetic resonance (NMR) has long emerged as a valuable technique for characterizing the molecular structure, conformation, and dynamics of polymer chains in various polymer systems. The principles of the solid-state 13C NMR cross-polarization experiment are described along with corresponding relaxation measurements. The ensuing recent applications of these techniques to different polymer systems are reviewed, with selected examples that have appeared in the recent literature. All of these applications of solid-state NMR to polymers have one feature in common: the interpretation of spectroscopic observations as related to the structural features and physical properties of the polymer
Combined laparoscopic pyelolithotomy and endoscopic pyelolithotripsy for staghorn calculi. Long-term follow-up results from a case series
Purpose: Staghorn renal stones are a challenging field in urology. Due to their high recurrence rates, particularly those associated with an infective process, a complete removal is the ultimate goal in their management. We report our experience with a combined approach of laparoscopic pyelolithotomy and endoscopic pyelolithotripsy, the stone clearance rate, and long-term, follow-up outcomes.
Methods: From June 2012 to October 2014, nine adult patients with large staghorn renal calculi (mean size, 7.2 cm; range, 6.2–9.0 cm) underwent a combined laparoscopic and endoscopic approach. The technique comprised laparoscopic pyelolithotomy and holmium-YAG laser stone fragmentation with the use of a flexible cystoscope introduced through a 12 mm trocar.
Results: The average operative time was 140 min (range, 90–190 min). The mean estimated hemoglobin loss was 0.6 mmol/l (range 0.5–0.7 mmol/l). None of the patients required an open- surgery conversion. The mean hospital stay was 4 days (range, 2–6 days). A computed tomography urogram control at 6 months of follow up did not show any stone recurrence.
Conclusions: Laparoscopic pyelolithotomy combined with endoscopic pyelolithotripsy could be a therapeutic option in cases where mini-invasive procedures, that is, extracorporeal shock wave lithotripsy, ureteroscopic lithotripsy, and percutaneous nephrolithotomy (PCNL) have failed. This technique has a high stone-clearance rate (75–100%) comparable with open surgery and PCNL. However, it could be technically demanding and should be performed by skilled laparoscopy surgeons
Can daily intake of aspirin and/or statins influence the behavior of non-muscle invasive bladder cancer? A retrospective study on a cohort of patients undergoing transurethral bladder resection
Background: This study aimed to evaluate the behavior of non-muscle-invasive bladder cancer (NMIBC) in patients
submitted to transurethral bladder resection (TURB) comparing subjects in chronic therapy with aspirin, statins, or
both drugs to untreated ones.
Methods: This retrospective study was conducted on 574 patients diagnosed with NMIBC who underwent TURB
between March 2008 and April 2013. The study population was divided into two main groups: treated (aspirin
and/or statins) and untreated. The treated group was further divided into three therapeutic subgroups: Group A
(100 mg of aspirin, daily for at least two years); Group B (20 mg or more of statins, daily for at least two years);
and Group C (100 mg of aspirin and 20 mg of statins together). The mean follow-up of patients was 45.06 months.
Results: No significant differences were observed among the different groups at baseline. On multivariate analysis,
statin treatment, smokers and high stage disease (T1) achieved the level of independent risk factor for the occurrence
of a recurrence. When patients were stratified according to the different treatment; patients treated with statins
(Group B) presented an higher rate of failure (56/91 patients; 61.5%) when compared to Group A (42/98 patients;
42.9%), Group C (56/98; 57.1%) and (133/287 patients; 46.3%). This difference corresponds to a significant difference
in recurrence failure free survival (p = 0.01).
Conclusions: Our results suggest that long-term treatment with aspirin in patients with NMIBC might play a role on
reducing the risk of tumor recurrence. In contrast, in our investigation data from statins and combination treatment
groups showed increased recurrence rates. A long-term randomized prospective study could definitively assess the
possible role of this widely used drugs in NMIBC
Sheaf Neural Networks for Graph-based Recommender Systems
Recent progress in Graph Neural Networks has resulted in wide adoption by
many applications, including recommendation systems. The reason for Graph
Neural Networks' superiority over other approaches is that many problems in
recommendation systems can be naturally modeled as graphs, where nodes can be
either users or items and edges represent preference relationships. In current
Graph Neural Network approaches, nodes are represented with a static vector
learned at training time. This static vector might only be suitable to capture
some of the nuances of users or items they define. To overcome this limitation,
we propose using a recently proposed model inspired by category theory: Sheaf
Neural Networks. Sheaf Neural Networks, and its connected Laplacian, can
address the previous problem by associating every node (and edge) with a vector
space instead than a single vector. The vector space representation is richer
and allows picking the proper representation at inference time. This approach
can be generalized for different related tasks on graphs and achieves
state-of-the-art performance in terms of F1-Score@N in collaborative filtering
and Hits@20 in link prediction. For collaborative filtering, the approach is
evaluated on the MovieLens 100K with a 5.1% improvement, on MovieLens 1M with a
5.4% improvement and on Book-Crossing with a 2.8% improvement, while for link
prediction on the ogbl-ddi dataset with a 1.6% refinement with respect to the
respective baselines.Comment: 9 pages, 7 figure
Systematic Human Reliability Analysis (SHRA): A New Approach to Evaluate Human Error Probability (HEP) in a Nuclear Plant
Emergency management in industrial plants is a fundamental issue to ensure the safety of operators. The emergency management analyses two fundamental aspects: the system reliability and the human reliability. System reliability is the capability of ensuring the functional properties within a variability of work conditions, considering the possible deviations due to unexpected events. However, system reliability is strongly related to the reliability of its weakest component. The complexity of the processes could generate incidental situations and the worker appears (human reliability) to be the weakest part of the whole system. The complexity of systems influences operator's ability to take decisions during emergencies. The aim of the present research is to develop a new approach to evaluate human error probability (HEP), called Systematic Human Reliability Analysis (SHRA). The proposed approach considers internal and external factors that affect operator's ability. The new approach is based on Nuclear Action Reliability Assessment (NARA), Simplified Plant Analysis Risk Human Reliability (SPAR-H) and on the Performance Shaping Factors (PSFs) relationship. The present paper analysed some shortcomings related to literature approaches, especially the limitations of the working time. We estimated HEP, after 8 hours (work standard) during emergency conditions. The correlations between the advantages of these three methodologies allows proposing a HEP analysis during accident scenarios emergencies. SHRA can be used to estimate human reliability during emergencies. SHRA has been applied in a nuclear accident scenario, considering 24 hours of working time. The SHRA results highlight the most important internal and external factors that affect operator's ability
Dynamic modeling of levitation of a superconducting bulk by coupled -magnetic field and Arbitrary Lagrangian-Eulerian formulations
Intrinsically stable magnetic levitation between superconductors and
permanent magnets can be exploited in a variety of applications of great
technical interest in the field of transportation (rail transportation), energy
(flywheels) and industry. In this contribution, we present a new model for the
calculation of levitation forces between superconducting bulks and permanent
magnet, based on the -formulation of Maxwell's equations coupled with an
Arbitrary Lagrangian-Eulerian formulation. The model uses a moving mesh that
adapts at each time step based on the time-change of the distance between a
superconductor bulk and a permanent magnet. The model is validated against a
fixed mesh model (recently in turn validated against experiments) that uses an
analytical approach for calculating the magnetic field generated by the moving
permanent magnet. Then, it is used to analyze the magnetic field dynamics both
in field-cooled and zero-field-cooled conditions and successively used to test
different configurations of permanent magnets and to compare them in terms of
levitation forces. The easiness of implementation of this model and its
flexibility in handling different geometries, material properties, and
application scenarios make the model an attractive tool for the analysis and
optimization of magnetic levitation-based applications
Mitotic cell death induction by targeting the mitotic spindle with tubulin-inhibitory indole derivative molecules
Tubulin-targeting molecules are widely used cancer therapeutic agents. They inhibit microtubule-based structures, including the mitotic spindle, ultimately preventing cell division. The final fates of microtubule-inhibited cells are however often heterogeneous and difficult to predict. While recent work has provided insight into the cell response to inhibitors of microtubule dynamics (taxanes), the cell response to tubulin polymerization inhibitors remains less well characterized. Arylthioindoles (ATIs) are recently developed tubulin inhibitors. We previously identified ATI members that effectively inhibit tubulin polymerization in vitro and cancer cell growth in bulk cell viability assays. Here we characterise in depth the response of cancer cell lines to five selected ATIs. We find that all ATIs arrest mitotic progression, yet subsequently yield distinct cell fate profiles in time-lapse recording assays, indicating that molecules endowed with similar tubulin polymerization inhibitory activity in vitro can in fact display differential efficacy in living cells. Individual ATIs induce cytological phenotypes of increasing severity in terms of damage to the mitotic apparatus. That differentially triggers MCL-1 down-regulation and caspase-3 activation, and underlies the terminal fate of treated cells. Collectively, these results contribute to define the cell response to tubulin inhibitors and pinpoint potentially valuable molecules that can increase the molecular diversity of tubulin-targeting agents
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