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Widespread Antarctic glaciation during the Late Eocene
No full textAbstractMarine sedimentary rocks drilled on the southeastern margin of the South Orkney microcontinent in Antarctica (Ocean Drilling Program Leg 113 Site 696) were deposited between ∼36.5 Ma to 33.6 Ma, across the Eocene–Oligocene climate transition. The recovered rocks contain abundant grains exhibiting mechanical features diagnostic of iceberg-rafted debris. Sand provenance based on a multi-proxy approach that included petrographic analysis of over 275,000 grains, detrital zircon geochronology and apatite thermochronometry rule out local sources (Antarctic Peninsula or the South Orkney Islands) for the material. Instead the ice-transported grains show a clear provenance from the southern Weddell Sea region, extending from the Ellsworth–Whitmore Mountains of West Antarctica to the coastal region of Dronning Maud Land in East Antarctica. This study provides the first evidence for a continuity of widespread glacier calving along the coastline of the southern Weddell Sea embayment at least 2.5 million yrs before the prominent oxygen isotope event at 34–33.5 Ma that is considered to mark the onset of widespread glaciation of the Antarctic continent
Development of a slender continuum robotic system for on-wing inspection/repair of gas turbine engines
No full textAbstractThe maintenance works (e.g. inspection, repair) of aero-engines while still attached on the airframes requires a desirable approach since this can significantly shorten both the time and cost of such interventions as the aerospace industry commonly operates based on the generic concept “power by the hour”. However, navigating and performing a multi-axis movement of an end-effector in a very constrained environment such as gas turbine engines is a challenging task. This paper reports on the development of a highly flexible slender (i.e. low diameter-to-length ratios) continuum robot of 25 degrees of freedom capable to uncoil from a drum to provide the feeding motion needed to navigate into crammed environments and then perform, with its last 6 DoF, complex trajectories with a camera equipped machining end-effector for allowing in-situ interventions at a low-pressure compressor of a gas turbine engine. This continuum robot is a compact system and presents a set of innovative mechatronics solutions such as: (i) twin commanding cables to minimise the number of actuators; (ii) twin compliant joints to enable large bending angles (±90°) arranged on a tapered structure (start from 40mm to 13mm at its end); (iii) feeding motion provided by a rotating drum for coiling/uncoiling the continuum robot; (iv) machining end-effector equipped with vision system. To be able to achieve the in-situ maintenance tasks, a set of innovative control algorithms to enable the navigation and end-effector path generation have been developed and implemented. Finally, the continuum robot has been tested both for navigation and movement of the end-effector against a specified target within a gas turbine engine mock-up proving that: (i) max. deviations in navigation from the desired path (1000mm length with bends between 45° and 90°) are ±10mm; (ii) max. errors in positioning the end-effector against a target situated at the end of navigation path is 1mm. Thus, this paper presents a compact continuum robot that could be considered as a step forward in providing aero-engine manufacturers with a solution to perform complex tasks in an invasive manner
Synthesis and butadiene polymerization behaviors of cationic cobalt-based catalyst
No full textAbstractA series of cationic cobalt-based compounds bearing different neutral N-bearing ligands (1,10-phenanthroline, bipyridine, benzimidazole, terpyridine) and anionic ligands (trifluoromethanesulfonate, methanesulfonate) were synthesized and the simple compound, Co(Phen)2Cl2, was also prepared as a reference compound. All the compounds were characterized along with infrared spectra analysis and some of them were further confirmed by single crystal X-ray crystallographic analysis. Upon activation with ethylaluminum sesquichloride, these cationic cobalt(II) compounds showed high catalytic activities for butadiene polymerization. The detailed investigations were carried out to disclose the influence of various polymerization conditions, sterical and electronic parameters of the ligands on their performing activities of the compounds
Stability and boundedness in delay system of differential equations of third order
No full textAbstractIn this paper, a class of non-linear vector differential equations of third order with delay is considered. The stability, boundedness and ultimately boundedness of solutions are studied. The technique of proofs involves defining an appropriate Lyapunov functional. The obtained results include and improve the results in the literature
γ-Diimine palladium(II) based complexes mediated polymerization of methyl methacrylate
No full textAbstractThe synthesis of new palladium(II) complexes of the type [Pd(A–NC–ph–CN–A)Cl2] (4a–e) (A=cyclohexyl (a), 2-isoprpropyl (b), pyrenyl (c), naphthyl (d), and 2,6-diisopropyl (e)) is described. The isolated γ-diimine ligands and their corresponding palladium(II) complexes were characterized by their physical properties, elemental analysis, 1H NMR-, 13C NMR, and infrared spectroscopy. The palladium(II) complexes (4a–e) were employed successfully as catalysts for atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in the presence of ethyl-2-bromoisobutyrate (EBIB) as initiator at 90°C. Polymerization with these catalyst systems afforded polymers with low molecular weight distribution (Mw/Mn) and syndio-rich atactic poly (MMA) with relatively higher [rr] diads
Primary non-Hodgkin's lymphoma of the common bile duct: A case report and literature review
No full textSummaryHepatobiliary involvement by malignant lymphoma is usually a secondary manifestation of systemic disease, whereas primary non-Hodgkin's lymphoma of the extrahepatic biliary ducts is an extremely rare entity. We describe the case of a 57-year-old man who presented with an acute onset of obstructive jaundice and severe itching. Abdominal ultrasonography and computed tomography revealed intrahepatic and common hepatic ducts dilatation. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography showed a mid-common bile duct stricture. The patient was presumed to have cholangiocarcinoma of the common bile duct, and an en bloc resection of the tumor with Roux-en-Y hepaticojejunostomy and porta-hepatis lymph nodes dissection was performed. Histopathology and immunohistochemistry revealed a large B cell non-Hodgkin's lymphoma. The patient received six cycles of combination chemotherapy using cyclophosphamide, vincristine, prednisone, and rituximab (CVP-R) protocol, and after a 5-year follow-up he is still in complete remission. We also reviewed the cases published from 1982 to 2012, highlighting the challenges in reaching a correct preoperative diagnosis and the treatment modalities used in each case
Efficacy and safety of bevacizumab-containing neoadjuvant therapy followed by interval debulking surgery in advanced ovarian cancer: Results from the ANTHALYA trial
No full textAbstractAimTo investigate whether adding bevacizumab to neoadjuvant carboplatin-paclitaxel (CP) helps achieve optimal debulking, measured by complete resection rate (CRR) at interval debulking surgery (IDS), in patients with initially unresectable International Federation of Gynecology and Obstetrics stage IIIC/IV ovarian, tubal or peritoneal adenocarcinoma.MethodsMulticentre, open-label, non-comparative phase II study. Ninety-five patients randomised (2:1) to receive four cycles of neoadjuvant CP ±3 concomitant cycles of bevacizumab 15 mg/kg (BCP) followed by IDS. Primary objective is to evaluate the CRR at IDS in the BCP group (reference CRR rate defined as 45% CRR). A stopping rule based on bevacizumab-related adverse events (AEs) of special interest was implemented.ResultsIn the BCP group (N = 58), IDS was performed in 40 (69%) patients, of whom 85% had a complete resection. The CRR of this group was therefore 58.6% (34 patients), statistically over pre-defined 45%. The CRR in the CP group was 51.4%: 22 (60%) patients underwent IDS (85% had a complete resection). Grade ≥3 adverse events occurred in 62% of the BCP-treated patients and 63% of the CP-treated patients: mainly blood and lymphatic, gastrointestinal and vascular disorders, without more toxicity with BCP. Postoperative complications (mainly wound, infectious and gastrointestinal complications) occurred in 28% and 36% of the patients, respectively. The pre-specified safety stopping rule was not reached.ConclusionThe primary objective was met as the CRR with BCP was significantly higher than the reference rate. Bevacizumab may be safely added to a preoperative program in patients deemed non-optimally resectable, whatever the final surgical decision. Bevacizumab's role in this setting should be further investigated
Optimal frequency selection of multi-channel O2-band different absorption barometric radar for air pressure measurements
No full textAbstractThrough theoretical analysis, optimal selection of frequencies for O2 differential absorption radar systems on air pressure field measurements is achieved. The required differential absorption optical depth between a radar frequency pair is 0.5. With this required value and other considerations on water vapor absorption and the contamination of radio wave transmission, frequency pairs of present considered radar system are obtained. Significant impacts on general design of differential absorption remote sensing systems are expected from current results
Analysis of ageing-associated grey matter volume in patients with multiple sclerosis shows excess atrophy in subcortical regions
No full textAbstractAge of onset in multiple sclerosis (MS) exerts an influence on the course of disease. This study examined whether global and regional brain volumes differed between “younger” and “older” onset MS subjects who were matched for short disease duration, mean 1.9years and burden as measured by the MS Severity Score and relapses.21 younger-onset MS subjects (age 30.4±3.2years) were compared with 17 older-onset (age 48.7±3.3years) as well as age-matched controls (n=31, 31.9±3.5years and n=21, 47.3±4.0years). All subjects underwent 3D volumetric T1 and T2-FLAIR imaging. White matter (WM) and grey matter (GM) lesions were outlined manually. Lesions were filled prior to tissue and structural segmentation to reduce classification errors.Volume loss versus control was predominantly in the subcortical GM, at >13% loss. Younger and older-onset MS subjects had similar, strong excess loss in the putamen, thalamus, and nucleus accumbens. No excess loss was detected in the amygdala or pallidum. The hippocampus and caudate showed significant excess loss in the younger group (p<0.001) and a strong trend in the older-onset group.These results provide a potential imaging correlate of published neuropsychological studies that reported the association of younger age at disease onset with impaired cognitive performance, including decreased working memory