264 research outputs found
Quantum Charge Transport and Conformational Dynamics of Macromolecules
We study the dynamics of quantum excitations inside macromolecules which can
undergo conformational transitions. In the first part of the paper, we use the
path integral formalism to rigorously derive a set of coupled equations of
motion which simultaneously describe the molecular and quantum transport
dynamics, and obey the fluctuation/dissipation relationship. We also introduce
an algorithm which yields the most probable molecular and quantum transport
pathways in rare, thermally-activated reactions. In the second part of the
paper, we apply this formalism to simulate the propagation of a charge during
the collapse of a polymer from an initial stretched conformation to a final
globular state. We find that the charge dynamics is quenched when the chain
reaches a molten globule state. Using random matrix theory we show that this
transition is due to an increase of quantum localization driven by dynamical
disorder.Comment: 11 pages, 2 figure
Radiological features of knee joint synovial chondromatosis
Synovial chondromatosis (SC) is a rare condition with a very variable clinical presentation, thus making the diagnosis not immediate. We report a case of massive primary SC of the knee, properly evaluated with X-rays, ultrasonography and magnetic resonance imaging and successfully treated with an arthroscopic approach
Series de precipitación de la región centro oeste y sus variaciones
Se analizan las series de precipitaciones estivales de 8 estaciones meteorológicas de la región Centro Oeste de la Argentina mediante la aplicación de filtros de baja y alta frecuencias.
Se establecen las matrices de correlación de las series originales y filtradas y se efectúa un análisis de enlace (linkage).
Los resultados muestran que la región presenta igual variabilidad,1as ondas lar gas que la componen se encuentran en fase, con un período de 18 años aproximadamente por lo que están altamente correlacionadas. Las ondas cortas, más representativas del microclima de cada estación, no se correlacionan.The records of summer rainfall from 8 meteorological stations in the Central West region of Argentina has been analyzed by means of low-pass and high-pass filters. Linkage analysis has also been applied to the correlation matrix of filtered and unfiltered data.
The results show that the region has equal variabllity, the long waves components are in face with a period of 18 years aproximately and high correlation coefficients.
The short waves are more representatives of the microclima of each station.
They are not correlated.Asociación Argentina de Geofísicos y Geodesta
Gestione ecosostenibile delle infestanti in ambiente urbano e vivaistico
In ottemperanza al nuovo quadro normativo relativo all’uso sostenibile dei prodotti fitosanitari (Direttiva 2009/128/CE - D.L. 150/2012, DM 22 gennaio 2014) il lavoro ha avuto lo scopo di verificare l’efficienza di strategie alternative alla gestione convenzionale della flora infestante in ambienti urbani e in vivai, comparando diserbo chimico tradizionale e meccanico con tecniche innovative. In particolare sono state valutate la tecnica del pirodiserbo, l’utilizzo di acqua a temperatura prossima al punto di ebollizione (sistema Eco Weed) e di acido pelargonico, un erbicida disseccante estratto la prima volta dalle foglie di Pelargonium roseum. La sperimentazione delle diverse tecniche di controllo è stata preceduta da uno studio della flora e della vegetazione al fine di pianificare nel modo più efficace gli interventi di contenimento delle infestanti, in funzione delle peculiarità delle specie e dell’habitat. I risultati hanno evidenziato concrete e valide alternative all’impiego del glifosate e del decespugliatore, sia in ambiente urbano che nei vivai
Treatment of the atrophic upper jaw : rehabilitation of two complex cases
In reconstructive surgery, the fresh frozen homologous bone (FFB) represents a valid alternative to the autologous bone, because FFB allows bone regeneration thanks to its osteoinductive and osteoconductive properties. The purpose of this work is to describe the surgical-implant-prosthetic treatment of two complex cases using FFB. In particular, fresh frozen homologous bone grafts were used to correct the severe atrophy of the maxilla, and, then, once the graft integration was obtained, implant therapy was performed and implants placed in native bone were immediately loade
CT imaging of primary pancreatic lymphoma: experience from three referral centres for pancreatic diseases
To describe CT characteristics of primary pancreatic lymphoma (PPL), a rare disease with features in common with adenocarcinoma
IFN-\u3b3 and other serum cytokines in head and neck squamous cell carcinomas
Altered immune responses have been reported in head and neck cancer, and some of these responses have been associated with poor clinical outcomes. A multiple-array technology platform was used to simultaneously evaluate the levels of 25 cytokines. Pre-treatment serum levels were evaluated in 31 HNSCC patients and 6 healthy controls. The levels of 8 cytokines, specifically IL-1ra, IL-2, IL-5, IL-6, IL-8, IL-17, IFN-\u3b3 and IP-10, were significantly higher in patients than in controls. Among cancer patients we observed lower levels of IFN-\u3b3 and IL-7 in cases with nodal metastases compared to those with cN0 disease. We observed increases in the levels of some serum cytokines in HNSCC patients, as well as reductions in selected cytokines associated with regional progression. These findings provide an intriguing perspective on the development and validation of novel markers for follow-up evaluations and predictions of regional spreading in HNSCC patients
TNM Staging of Neoplasms of the Endocrine Pancreas: Results From a Large International Cohort Study
Background Both the European Neuroendocrine Tumor Society (ENETS) and the International Union for Cancer Control/American Joint Cancer Committee/World Health Organization (UICC/AJCC/WHO) have proposed TNM staging systems for pancreatic neuroendocrine neoplasms. This study aims to identify the most accurate and useful TNM system for pancreatic neuroendocrine neoplasms. Methods The study included 1072 patients who had undergone previous surgery for their cancer and for which at least 2 years of follow-up from 1990 to 2007 was available. Data on 28 variables were collected, and the performance of the two TNM staging systems was compared by Cox regression analysis and multivariable analyses. All statistical tests were two-sided. Results Differences in distribution of sex and age were observed for the ENETS TNM staging system. At Cox regression analysis, only the ENETS TNM staging system perfectly allocated patients into four statistically significantly different and equally populated risk groups (with stage I as the reference; stage II hazard ratio [HR] of death = 16.23, 95% confidence interval [CI] = 2.14 to 123, P = .007; stage III HR of death = 51.81, 95% CI = 7.11 to 377, P < .001; and stage IV HR of death = 160, 95% CI = 22.30 to 1143, P < .001). However, the UICC/AJCC/WHO 2010 TNM staging system compressed the disease into three differently populated classes, with most patients in stage I, and with the patients being equally distributed into stages II-III (statistically similar) and IV (with stage I as the reference; stage II HR of death = 9.57, 95% CI = 4.62 to 19.88, P < .001; stage III HR of death = 9.32, 95% CI = 3.69 to 23.53, P = .94; and stage IV HR of death = 30.84, 95% CI = 15.62 to 60.87, P < .001). Multivariable modeling indicated curative surgery, TNM staging, and grading were effective predictors of death, and grading was the second most effective independent predictor of survival in the absence of staging information. Though both TNM staging systems were independent predictors of survival, the UICC/AJCC/WHO 2010 TNM stages showed very large 95% confidence intervals for each stage, indicating an inaccurate predictive ability. Conclusion Our data suggest the ENETS TNM staging system is superior to the UICC/AJCC/WHO 2010 TNM staging system and supports its use in clinical practic
Constraints on (2060) Chiron's size, shape, and surrounding material from the November 2018 and September 2019 stellar occultations
After the discovery of rings around the largest known Centaur object, (10199)
Chariklo, we carried out observation campaigns of stellar occultations produced
by the second-largest known Centaur object, (2060) Chiron, to better
characterize its physical properties and presence of material on its
surroundings. We predicted and successfully observed two stellar occultations
by Chiron. These observations were used to constrain its size and shape by
fitting elliptical limbs with equivalent surface radii in agreement with
radiometric measurements. Constraints on the (2060) Chiron shape are reported
for the first time. Assuming an equivalent radius of R =
105 km, we obtained a semi-major axis of a = 126 22 km.
Considering Chiron's true rotational light curve amplitude and assuming it has
a Jacobi equilibrium shape, we were able to derive a 3D shape with a semi-axis
of a = 126 22 km, b = 109 19 km, and c = 68 13 km, implying
in a volume-equivalent radius of R = 98 17 km, implying a density
of 1119 4 kg m. We determined the physical properties of the 2011
secondary events around Chiron, which may then be directly compared with those
of Chariklo rings, as the same method was used. Data obtained from SAAO in 2018
do not show unambiguous evidence of the proposed rings, mainly due to the large
sampling time. Meanwhile, we discarded the possible presence of a permanent
ring similar to (10199) Chariklo's C1R in optical depth and extension. Using
the first multi-chord stellar occultation by (2060) Chiron and considering it
to have a Jacobi equilibrium shape, we derived its 3D shape. New observations
of a stellar occultation by (2060) Chiron are needed to further investigate the
material's properties around Chiron, such as the occultation predicted for
September 10, 2023
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