2,325 research outputs found
Evaluation of MMP‑2, MMP‑9, TIMP‑1, TIMP‑2, NGAL and MMP‑9/NGAL complex in urine and sera from patients with bladder cancer
The identification of biomarkers in urine or serum samples from patients with bladder cancer is urgently required for the development of non-invasive methods for the diagnosis of bladder carcinoma and to facilitate follow-up surveillance, to combat the high progression and recurrence rates of this type of cancer. The current study measured the content of matrix metalloproteinase (MMP)-2 and -9, as well as tissue inhibitor of metalloproteinase (TIMP)-1 and -2 in the urine and sera of 41 patients with bladder cancer by ELISA. The association between levels of MMP-2 and -9 and TIMP-1 and -2, and tumor grade and stage were investigated to verify whether these molecules are involved in tumor differentiation. Statistical analysis of the data revealed that urinary TIMP-1 levels were significantly higher in the high grade group compared with those of the low grade samples (P=0.022). The results also revealed a significantly differing distribution of TIMP-1 expression between Ta and T1 stage specimens (P=0.040). The corresponding area under the curves (AUCs) were 0.72, with a sensitivity of 0.70 and specificity of 0.75. In addition, neutrophil gelatinase-associated lipocalin (NGAL) and MMP-9/NGAL complex levels in the sera were measured. All molecules evaluated were detected in the sera of the patients studied. In particular, tumors staged as non-muscle invasive (Ta and T1), demonstrated significantly higher NGAL levels compared with those of muscle invasive (>T1) bladder cancer (32.8 ng/ml vs. 16.2 ng/ml; P=0.029). The discriminatory ability of NGAL expression was confirmed by receiver operating characteristic curve analysis that revealed an AUC of 0.75, a sensitivity of 0.88 and a specificity of 0.67. These data indicated that urinary TIMP-1 and serum NGAL may be useful non-invasive biomarkers to provide clinical information for bladder cancer disease management. Multicenter, prospective studies are required to confirm these preliminary results
Harmonic current sideband indicators (HCSBIs) for broken bar detection and diagnostics in cage induction motors
Induction motor bar breakages have been increasingly studied in the last decades because of
economic interests in developing techniques that permit on-line, non-invasive, early detection
of motor faults in power plants. This work is specifically focused on
broken bar detection and fault severity assessment in three phase power cage motors fed by
non-sinusoidal voltage sources. In this work some new fault indicators for rotor bar breakages detection in squirrel cage
induction motors are proposed, mathematically developed and
experimentally proved.
They are based on the sidebands of phase current upper harmonics, and they are well suited
especially for converter-fed induction motors. The ratios I(7-2s)f/I5f and I(5+2s)f/I7f , I(13-2s)f/I11f and
I(11+2s)f/I13f are examples of such new indicators, and they are not dependent on load torque
and drive inertia, as classical indicators do. Their frequency-dependence has been also examined both theoretically and experimentally, and it was found less remarkable with respect to
other indicators. Moreover, their values increase linearly with the quantity of consecutive
broken bars, almost for not too much advanced faults; on 4-poles motors they were
found quietly like the per-unit number of broken bars (ratio on total bar number).
An original formulation is presented for motor mathematical modeling, based on the
Generalized Symmetrical Components Theory, for sidebands amplitude computation. A complete motor model (involving all the elementary machine
electrical circuits, as stator belts and rotor mesh loops) has been used for computer simulations; the same model was then transformed by using some complex Fortescue’s matrices to
obtain a steady-state linear solution, solvable for stator and rotor currents, in healthy and faulty
conditions. By exploiting the model, the formal definition of a set of new broken bar
indicators was finally obtained. Machine simulations carried out by running the
complete numerical model confirmed the accuracy of the model, and the theoretical previsions.
Experimental work was performed by using a square-wave inverter-fed motor with an
appositely prepared cage, for easy testing with increasing number of
broken bars and without motor dismounting. Moreover, extensive experimentation was carried out on three industrial motors with different power and poles number, with
increasing load, frequency and fault gravity for methodology validation.
Finally, the ideas exposed in this work led to a patent application, owned by the University of Rome “Sapienza”
An Analysis of Florida Educators\u27 Perceptions of the School Superintendency, Qualifications, Leadership Skills, Longevity, and Student Achievement: A Quantitative Study
High turnover in the role of school superintendent signaled functional disruption, decreased morale and impaired student achievement. The principal researcher sought to explain perceptions among professional Florida K-12 public school educators about key factors related to the role of school superintendent, necessary qualifications, important leadership skills, longevity and its impact on student achievement.
The principal researcher disseminated a 10-question online self-administered survey she developed for the study to a sample of 199 professional Florida K-12 public school educators. Independent demographic variables among sample participants included: gender, current job, highest level of completed education and years of experience as an educator. Dependent variables included: qualifications, leadership skills, longevity and student achievement. In this her final report, the principal researcher documented the problem, presented a literature review and research methodology, reported descriptive analysis of simple frequencies for guiding research question one and reported findings of nonparametric Kruskall -Wallis H testing for guiding research questions two through five. Current job was statistically significant in sample participant perceptions. School teachers rated a doctoral degree in education, 10+ years’ experience in education and experience in the same district more highly as necessary qualifications for school superintendent candidates than did school and district leaders. School teachers also rated advocating for employees, trust and confidence in employees and fairness and integrity more essential than did school and district leaders, as important leadership skills related to school superintendent longevity. School leaders rated longevity and student achievement more essential than did school teachers and district leaders, as factors related to the role of school superintendent. School leaders also rated classroom teachers experience more highly than did school teachers and district leaders as a necessary qualification for school superintendent candidates. Finally, school leaders rated more highly than school teachers and district leaders a four-to-10-year term of service for school superintendents for maximum impact on student achievement. Discussion, elaboration and interpretation of findings, implications of findings and recommendations for future research are included herein
Electronic and Geometric Structure of Copper Single-Metal Sites in Zeolites by Hyperfine Spectroscopy and Quantum Chemical Modelling
A Thesis submitted to the Universities of Leipzig and Turin in candidature for a Joint PhD degree by Paolo Cleto Bruzzese
Abstract
Atomically dispersed transition metal ions in zeolites catalyse a wide range of
industrial reactions and are at the centre of intense research interest to design
new sustainable synthetic pathways for energy conversion and environment remediation.
One of the big challenges in this context is the characterization and
location of the active sites. Indeed, mapping their nature with atomic-scale
precision occupies a central place in the theory and practice of heterogeneous
catalysis.
In this thesis, the site-selectivity and sensitivity of Electron Paramagnetic
Resonance (EPR) with its pulsed variants are combined with quantum chemical
modelling to determine the microscopic structure of monomeric CuII species in
zeolites with Chabazite (CHA) topology as a function of the hydration conditions
and sample composition. By isotopic labelling of the zeolite framework
with 17O and employing 17O ENDOR spectroscopy, the degree of covalency in
the Cu-O bond is mapped and the evolution of CuII sites as a function of the
hydration conditions is followed. By combining 1H HYSCORE experiments with
state-of-the-art quantum chemical modelling, the EPR signature of the redox active
hydroxo-CuII species is univocally identified and a quantitative assessment
of its electronic and geometric structureis provided as a function of zeolite composition
Optical emission investigation of laser-produced MgB2 plume expanding in an Ar buffer gas
Optical emission spectroscopy is used to study the dynamics of the plasma
generated by pulsed-laser irradiation of a MgB2 target, both in vacuum and at
different Ar buffer gas pressures. The analysis of the time-resolved emission
of selected species shows that the Ar background gas strongly influences the
plasma dynamics. Above a fixed pressure, plasma propagation into Ar leads to
the formation of blast waves causing both a considerable increase of the
fraction of excited Mg atoms and a simultaneous reduction of their kinetic flux
energy. These results can be particularly useful for optimizing MgB2 thin film
deposition processes.Comment: 11 pages,4 figures, Applied Physics Letters in pres
Estudio del Palacio Arzobispal de Alcalá de Henares
El Palacio Arzobispal de Alcalá de Henares es un tesoro histórico del que quedan importantes restos que deben recuperarse y reubicarlos a su lugar original, reconstruyendo la parte del conjunto que aún es posible volver a levantar. En la actualidad, el terreno ocupado por el palacio no nos deja huellas de haber sido lo que fue y haber tenido el auge que tuvo. Su restauración sería un aporte importante en consonancia con las políticas de recuperación patrimonial que esta ciudad ha implementado en las últimas décadas. En particular, la historia de la fachada o pórtico renacentista del Ave María nos vincula directamente a la fundación de la ciudad de Alcalá de Henares y su proceso de urbanización como recinto fortificado y casco urbano amurallado durante los siglos IX y X, y su ampliación con nueva muralla en el siglo XV. El objetivo del trabajo fue generar un proyecto de restauración de dicha fachada. El trabajo realizado, recogió aportes y estrategias de diferentes disciplinas relacionadas con la restauración y de esta forma incluir todos los pasos necesarios que un conjunto monumental de fuerte impacto territorial y paisajístico, como lo es el Palacio Arzobispal de Alcalá de Henares, requiere para la restauración y rehabilitación.Tópico 1: Aspectos teóricos, históricos, legales, económicos y tecnológicos de la restauración y conservación de bienes patrimoniales
Motori Elettrici Lineari ad Elevata Spinta per Applicazioni Navali
Gli attuatori oleodinamici usati per timonerie e pinne stabilizzatrici sviluppano elevate coppie a basse velocit\ue0. Viene presentato, in alternativa, un innovativo motore elettrico lineare ad elevata spinta alimentato da inverter per azionamenti diretti a bordo nave, che offre grandi vantaggi in termini di compattezza, manutenzione, efficienza, e tolleranza al guasto
Spazio pubblico e attrattività urbana. L'Isola e le sue piazze
L’Isola e le sue piazze è un progetto di valorizzazione urbana
integrata promosso nel gennaio 2015 da Comune di Milano,
Regione Lombardia e Distretto urbano del commercio Isola,
volto a promuovere l’identità del quartiere Isola, attraverso
la realizzazione di arredi temporanei, eventi e un piano di
comunicazione.
Entro tale contesto, un gruppo multidisciplinare di ricerca
del Politecnico di Milano afferente ai dipartimenti di
Architettura e Studi Urbani e di Design, attraverso mappature
e rilievi, osservazione diretta e interviste, ha condotto
un lavoro di accompagnamento e monitoraggio della proposta
risultata vincitrice del bando pubblico.
Il volume restituisce gli esiti della ricerca: descrive lo sfondo
entro cui è maturato il progetto, racconta le specificità del
quartiere, la qualità del suo spazio pubblico, le geografie
dell’offerta economica. I testi degli autori della ricerca si
intrecciano alle voci di abitanti, di testimoni privilegiati, di
rappresentanti delle istituzioni e dell’associazionismo
locale che a vario titolo sono stati coinvolti dal progetto, con
l’obiettivo di riflettere sulle molteplici dimensioni dello
spazio pubblico e dell’attrattività urbana: dagli usi formali e
informali ai servizi commerciali di prossimità, dagli eventi
che hanno avuto luogo nel periodo osservato alle dinamiche
che hanno innescato, fino agli esiti di un inedito bando e alle
opportunità della sua replicabilità
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