Bifurcations and chaos in single-roll natural convection with low Prandtl number

Convective flows of a small Prandtl number fluid contained in a two-dimensional cavity subject to a lateral thermal gradient are numerically studied by using different techniques. The aspect ratio (length to height) is kept at around 2. This value is found optimal to make the flow most unstable while keeping the basic single-roll structure. Two cases of thermal boundary conditions on the horizontal plates are considered: perfectly conducting and adiabatic. For increasing Rayleigh numbers we find a transition from steady flow to periodic oscillations through a supercritical Hopf bifurcation that maintains the centrosymmetry of the basic circulation. For a Rayleigh number of about ten times that of the Hopf bifurcation the system initiates a complex scenario of bifurcations. In the conductive case these include a quasiperiodic route to chaos. In the adiabatic one the dynamics is dominated by the interaction of two Neimark-Sacker bifurcations of the basic periodic solutions, leading to the stable coexistence of three incommensurate frequencies, and finally to chaos. In all cases, the complex time-dependent behavior does not break the basic, single-roll structure.

Outcome and prognostic factors in olfactory neuroblastoma: a rare cancer network study.

Purpose: To assess the outcome in patients with olfactory neuroblastoma (ONB). Methods and Materials: Seventy-seven patients treated for nonmetastatic ONB between 1971 and 2004 were included. According to Kadish classification, there were 11 patients with Stage A, 29 with Stage B, and 37 with Stage C. T-classification included 9 patients with T1, 26 with T2, 16 with T3, 15 with T4a, and 11 with T4b tumors. Sixty-eight patients presented with N0 (88%) disease. Results: Most of the patients (n = 56, 73 %) benefited from surgery (S), and total excision was possible in 44 patients (R0 in 32, R1 in 13, R2 in 11). All but five patients benefited from RT, and chemotherapy was given in 21(27%). Median follow-up period was 72 months (range, 6-315). The 5-year overall survival (OS), disease-free survival (DES), locoregional control, and local control were 64%, 57%, 62%, and 70%, respectively. In univariate analyses, favorable factors were Kadish A or B disease, T1 T3 tumors, no nodal involvement, curative surgery, R0/R1 resection, and RT-dose 54 Gy or higher. Multivariate analysis revealed that the best independent factors predicting the outcome were T1 T3, N0, R0/R1 resection, and total RT dose (54 Gy or higher). Conclusion: In this multicenter retrospective study, patients with ONB treated with R0 or R1 surgical resection followed by at least 54-Gy postoperative RT had the best outcome. Novel strategies including concomitant chemotherapy and/or higher dose RT should be prospectively investigated in this rare disease for which local failure remains a problem.

Optimization of laser interferometers for the detection of gravitational waves from coalescing binaries

Coalescing compact binary systems are important sources of gravitational waves. Here we investigate the detectability of this gravitational radiation by the recently proposed laser interferometers. The spectral density of noise for various practicable configurations of the detector is also reviewed. This includes laser interferometers with delay lines and Fabry-Prot cavities in the arms, both in standard and dual recycling arrangements. The sensitivity of the detector in all those configurations is presented graphically and the signal-to-noise ratio is calculated numerically. For all configurations we find values of the detector's parameters which maximize the detectability of coalescing binaries, the discussion comprising Newtonian- as well as post-Newtonian-order effects. Contour plots of the signal-to-noise ratio are also presented in certain parameter domains which illustrate the interferometer's response to coalescing binary signals.

A post-processing pipeline to reconstruct the developing fetal brain using low-resolution MRI

Introduction. Development of the fetal brain surfacewith concomitant gyrification is one of the majormaturational processes of the human brain. Firstdelineated by postmortem studies or by ultrasound, MRIhas recently become a powerful tool for studying in vivothe structural correlates of brain maturation. However,the quantitative measurement of fetal brain developmentis a major challenge because of the movement of the fetusinside the amniotic cavity, the poor spatial resolution,the partial volume effect and the changing appearance ofthe developing brain. Today extensive efforts are made todeal with the âeurooepost-acquisitionâeuro reconstruction ofhigh-resolution 3D fetal volumes based on severalacquisitions with lower resolution (Rousseau, F., 2006;Jiang, S., 2007). We here propose a framework devoted tothe segmentation of the basal ganglia, the gray-whitetissue segmentation, and in turn the 3D corticalreconstruction of the fetal brain. Method. Prenatal MRimaging was performed with a 1-T system (GE MedicalSystems, Milwaukee) using single shot fast spin echo(ssFSE) sequences in fetuses aged from 29 to 32gestational weeks (slice thickness 5.4mm, in planespatial resolution 1.09mm). For each fetus, 6 axialvolumes shifted by 1 mm were acquired (about 1 min pervolume). First, each volume is manually segmented toextract fetal brain from surrounding fetal and maternaltissues. Inhomogeneity intensity correction and linearintensity normalization are then performed. A highspatial resolution image of isotropic voxel size of 1.09mm is created for each fetus as previously published byothers (Rousseau, F., 2006). B-splines are used for thescattered data interpolation (Lee, 1997). Then, basalganglia segmentation is performed on this superreconstructed volume using active contour framework witha Level Set implementation (Bach Cuadra, M., 2010). Oncebasal ganglia are removed from the image, brain tissuesegmentation is performed (Bach Cuadra, M., 2009). Theresulting white matter image is then binarized andfurther given as an input in the Freesurfer software(http://surfer.nmr.mgh.harvard.edu/) to provide accuratethree-dimensional reconstructions of the fetal brain.Results. High-resolution images of the cerebral fetalbrain, as obtained from the low-resolution acquired MRI,are presented for 4 subjects of age ranging from 29 to 32GA. An example is depicted in Figure 1. Accuracy in theautomated basal ganglia segmentation is compared withmanual segmentation using measurement of Dice similarity(DSI), with values above 0.7 considering to be a verygood agreement. In our sample we observed DSI valuesbetween 0.785 and 0.856. We further show the results ofgray-white matter segmentation overlaid on thehigh-resolution gray-scale images. The results arevisually checked for accuracy using the same principlesas commonly accepted in adult neuroimaging. Preliminary3D cortical reconstructions of the fetal brain are shownin Figure 2. Conclusion. We hereby present a completepipeline for the automated extraction of accuratethree-dimensional cortical surface of the fetal brain.These results are preliminary but promising, with theultimate goal to provide âeurooemovieâeuro of the normal gyraldevelopment. In turn, a precise knowledge of the normalfetal brain development will allow the quantification ofsubtle and early but clinically relevant deviations.Moreover, a precise understanding of the gyraldevelopment process may help to build hypotheses tounderstand the pathogenesis of several neurodevelopmentalconditions in which gyrification have been shown to bealtered (e.g. schizophrenia, autismâeuro¦). References.Rousseau, F. (2006), 'Registration-Based Approach forReconstruction of High-Resolution In Utero Fetal MR Brainimages', IEEE Transactions on Medical Imaging, vol. 13,no. 9, pp. 1072-1081. Jiang, S. (2007), 'MRI of MovingSubjects Using Multislice Snapshot Images With VolumeReconstruction (SVR): Application to Fetal, Neonatal, andAdult Brain Studies', IEEE Transactions on MedicalImaging, vol. 26, no. 7, pp. 967-980. Lee, S. (1997),'Scattered data interpolation with multilevel B-splines',IEEE Transactions on Visualization and Computer Graphics,vol. 3, no. 3, pp. 228-244. Bach Cuadra, M. (2010),'Central and Cortical Gray Mater Segmentation of MagneticResonance Images of the Fetal Brain', ISMRM Conference.Bach Cuadra, M. (2009), 'Brain tissue segmentation offetal MR images', MICCAI.

Performance of Strip Seals in Iowa Bridges, Project TR-437, January 2001

A pilot study was conducted on the premature failures of neoprene strip seals in expansion joints in Iowa bridges. In a relatively large number of bridges, strip seals have pulled out of the steel extrusions or otherwise failed well before the expected life span of the seal. The most serious consequence of a strip-seal failure is damage to the bridge substructure due to salt, water, and debris interacting with the substructure. A literature review was performed. Manufacturers’ specifications and recommendations, practices in the states bordering Iowa, and Iowa DOT design and installation guidelines were reviewed. Discussions were held with bridge contractors and the installation of a strip seal system was observed. Iowa DOT bridge databases were analyzed. A national survey was conducted on the use and performance of strip seals. With guidance from the Iowa DOT, twelve in-service bridges with strip-seal expansion joints were selected for detailed investigation. Effective bridge temperatures and corresponding expansion-joint openings were measured, DOT inspection reports were reviewed, and likely cause(s) of premature failures of strip seals were proposed. All of the seals used in the twelve bridges that had the most serious failures were in concrete girder bridges. Experimental results show that for a majority of these serious failures, the joint opening at 0° F predicted by the Iowa DOT design equations, the joint opening at 0° F extrapolated from the experimental data, or both, are larger than the movement rating of the strip seal specified on the bridge plans. Other likely causes of premature failures of seals in the twelve bridges include debris and ice in the seal cavity, a large skew and the corresponding decrease in the movement rating of the seal, improper installation, and improper setting of the initial gap.

Supraclavicular flap in head and neck reconstruction: experience in 50 consecutive patients.

The supraclavicular flap (SCF) is a fasciocutaneous flap used to cover head, oral, and neck region defects after tumor resection. Its main vascular supply is the supraclavicular artery and accompanying veins and it can be harvested as a vascularised pedicled flap. The SCF serves as an excellent outer skin cover as well as a good inner mucosal lining after oral cavity and head-neck tumor resections. The flap has a wide arc of rotation and matches the skin colour and texture of the face and neck. Between March 2006 and March 2011, the pedicled supraclavicular flap was used for reconstruction in 50 consecutive patients after head and neck tumor resections and certain benign conditions in a tertiary university hospital setting. The flaps were tunnelized under the neck skin to cover the external cervicofacial defects or passed medial to the mandible to give an inner epithelial lining after the oral cavity and oropharyngeal tumor excision. Forty-four of the 50 patients had 100% flap survival with excellent wound healing. All the flaps were harvested in less than 1 h. There were four cases of distal tip desquamation and two patients had complete flap necrosis. Distal flap desquamation was observed in SCFs used for resurfacing the external skin defects after oral cavity tumor ablation and needed only conservative treatment measures. Total flap failure was encountered in two patients who had failed in previous chemoradiotherapy for squamous cell cancer of the floor of mouth and tonsil, respectively, and the SCF was used in mucosal defect closure after tumor ablation. The benefits of a pedicled fasciocutaneous supraclavicular flap are clear; it is thin, reliable, easy, and quick to harvest. In head, face and neck reconstructions, it is a good alternative to free fasciocutaneous flaps, regional pedicled myocutaneous flaps, and the deltopectoral flap.

Epac contributes to cardiac hypertrophy and amyloidosis induced by radiotherapy but not fibrosis.

BACKGROUND: Cardiac toxicity is a side-effect of anti-cancer treatment including radiotherapy and this translational study was initiated to characterize radiation-induced cardiac side effects in a population of breast cancer patients and in experimental models in order to identify novel therapeutic target. METHODS: The size of the heart was evaluated in CO-HO-RT patients by measuring the Cardiac-Contact-Distance before and after radiotherapy (48months of follow-up). In parallel, fibrogenic signals were studied in a severe case of human radiation-induced pericarditis. Lastly, radiation-induced cardiac damage was studied in mice and in rat neonatal cardiac cardiomyocytes. RESULTS: In patients, time dependent enhancement of the CCD was measured suggesting occurrence of cardiac hypertrophy. In the case of human radiation-induced pericarditis, we measured the activation of fibrogenic (CTGF, RhoA) and remodeling (MMP2) signals. In irradiated mice, we documented decreased contractile function, enlargement of the ventricular cavity and long-term modification of the time constant of decay of Ca(2+) transients. Both hypertrophy and amyloid deposition were correlated with the induction of Epac-1; whereas radiation-induced fibrosis correlated with Rho/CTGF activation. Transactivation studies support Epac contribution in hypertrophy stimulation and showed that radiotherapy and Epac displayed specific and synergistic signals. CONCLUSION: Epac-1 has been identified as a novel regulator of radiation-induced hypertrophy and amyloidosis but not fibrosis in the heart.

Idiopaattinen kylothorax : koiran ja kissan selvittämätön rintaontelon ongelma

Summary: Idiopathic chylothorax - unsolved problem in the pleural cavity in a dog and a cat

Vascular postpneumonectomy syndrome: inferior vena cava and pulmonary vein compression as unusual cause for platypnea-orthodeoxia following pneumonectomy

Background: Excessive mediastinal shift into the vacated thoracic cavity after pneumonectomy can result in dyspnea without hypoxemia by compression of the tracheobronchial tree, a phenomenon called postpneumonectomy syndrome. More rarely hypoxemia in upright position (platypnea-orthodeoxia syndrome, POS) after pneumonectomy can result from re-opening of an atrial right-to-left shunt through a patent foramen ovale (PFO) due to mediastinal distorsion. Review of literature also shows a unique report of pulmonary veins stenosis resulting in POS without intracardiac shunt after pneumonectomy. Methods: We report the case of a 32-year-old woman who presented POS 6 months after right pneumonectomy for destroyed lung post tuberculosis. Results: The patient described severe dyspnea disappearing when lying. SpO2 decreased from 94% when lying to 60% sitting. Transthoracic echocardiography (TTE) suspected a possible PFO. We first tried to highlight clinical repercussions of PFO by noninvasive exams. Hyperoxia shunt quantification was not tolerated because of increased dyspnea in sitting position. Contrast bubbles TTE was difficult because of the important mediastinal shift but identified only rare left heart bubbles with/without Valsalva both in lying and sitting position, excluding a significant right-to-left shunt. A lung perfusion scintigraphy (injection while sitting) confirmed the absence of systemic isotope uptake. Computed tomographic pulmonary angiography (angio-CT) revealed a stretched but not stenosed left main bronchus, while the shift of the heart into the right cavity was major. Pulmonary angiography did not show embolism but revealed compression of the inferior vena cava (IVC) with impaired venous return to the right heart, as well as compression of the left pulmonary veins. There was no arteriovenous shunt. Cardiac MRI showed torsion of IVC at the level of the diaphragm, and strong atrial contraction contributing to a passive filling of the RV, while the right ventricle was normal. Right catheterism showed major hemodynamic disturbances with negative diastolic pressure in right heart cavities (atrium -12 mm Hg ventricle pressure -7 mm Hg). SaO2 measured in the pulmonary artery decreased from 58% when lying to 45% sitting. Conclusion: We described here an exceedingly rare and complex mechanism explaining POS after right pneumonectomy. Mediastinal repositioning with a silicone breast implant of appropriate size has been scheduled.

Ponction pleurale [Thoracentesis]

Thoracentesis is a procedure consisting in the insertion of a needle in the pleural space. It is used to remove and analyse pleural fluid. Based on a review of the literature, this article describes the indications, the contraindications, the complications and the technique of this commonly performed procedure.

Correlation between subjective evaluation of symptoms and objective findings in early recurrent head and neck squamous cell carcinoma.

IMPORTANCE: This study addresses the value of patients' reported symptoms as markers of tumor recurrence after definitive therapy for head and neck squamous cell carcinoma. OBJECTIVE: To evaluate the correlation between patients' symptoms and objective findings in the diagnosis of local and/or regional recurrences of head and neck squamous cell carcinomas in the first 2 years of follow-up. DESIGN: Retrospective single-institution study of a prospectively collected database. SETTING: Regional hospital. PARTICIPANTS: We reviewed the clinical records of patients treated for oral cavity, oropharyngeal, laryngeal, and hypopharyngeal carcinomas between January 1, 2008, and December 31, 2009, with a minimum follow-up of 2 years. MAIN OUTCOMES AND MEASURES: Correlation between symptoms and oncologic status (recurrence vs remission) in the posttreatment period. RESULTS: Of the 101 patients included, 30 had recurrences. Pain, odynophagia, and dysphonia were independently correlated with recurrence (odds ratios, 16.07, 11.20, and 5.90, respectively; P < .001). New-onset symptoms had the best correlation with recurrences. Correlation was better between 6 to 12 and 18 to 21 months after therapy and in patients initially treated unimodally (P < .05). Primary stage and tumor site had no effect. CONCLUSIONS AND RELEVANCE: The correlation between symptoms and oncologic status is low during substantial periods within the first 2 years of follow-up. New-onset symptoms, especially pain, odynophagia, or dysphonia, better correlate with tumor recurrence, especially in patients treated unimodally.

A Neanderthal Lower Incisor from Cova del Gegant (Sitges, Barcelona, Spain)

Cova del Gegant is located near the city of Sitges (Barcelona, Spain). The cave is a small karst system which contains Upper Pleistocene archaeological and paleontological material (DauRa et al., 2005). The site was first excavated in 1954 and then in 1972 and 1974- (Viñas, 1972; Viñas & Villalta, 1975) and in 1985 and 1989 (maRtínez et al., 1985; moRa, 1988; maRtínez et al., 1990). Finally, in 2007, Grup de Recerca del Quaternari has restarted the archaeological research at Cova del Gegant (DauRa, 2008; DauRa et al., 2010). A human mandible was recovered during the first field season in 1954 and was recently published by DauRa et al. (2005). In the present study, we describe a new human tooth (left I2) that appeared, like the mandible, in a revision of the faunal material recovered from the site in 1974-1975. The specimen preserves the entire crown and the cervical two thirds of the root (Figure 1). The lack of the root apex makes it difficult to determine if the tooth was fully developed at the time of death. However, CT analysis reveals a pulp cavity that could be still open, suggesting root formation was incomplete. The specimen shows only slight dental wear corresponding to stage 2 of Molnar (1971 en Hillson, 1996). Morphologically, the crown shows slight shovelling and a lingual tubercle and appears similar to Neandertal incisors. Standard crown measurements (buccolingual diameter=7.7 mm; mesiodistal diameter= 7.3 mm) (Figure 2) suggest a fairly large tooth, particularly in the BL dimension, again resembling Neandertals in this regard. Discriminant analysis classified the Gegant incisor as Neandertal with a 99.8% posterior probability (Table 2). Association of this tooth with the previously described mandible is considered unlikely given the different ages at death estimated for each. Thus, there appear to be two individuals preserved in the sediments of the Gegant cave, one adult and one subadult (around 8-10 years old).

Photopolymerizable hydrogels for implants: Monte-Carlo modeling and experimental in vitro validation.

Photopolymerization is commonly used in a broad range of bioapplications, such as drug delivery, tissue engineering, and surgical implants, where liquid materials are injected and then hardened by means of illumination to create a solid polymer network. However, photopolymerization using a probe, e.g., needle guiding both the liquid and the curing illumination, has not been thoroughly investigated. We present a Monte Carlo model that takes into account the dynamic absorption and scattering parameters as well as solid-liquid boundaries of the photopolymer to yield the shape and volume of minimally invasively injected, photopolymerized hydrogels. In the first part of the article, our model is validated using a set of well-known poly(ethylene glycol) dimethacrylate hydrogels showing an excellent agreement between simulated and experimental volume-growth-rates. In the second part, in situ experimental results and simulations for photopolymerization in tissue cavities are presented. It was found that a cavity with a volume of 152  mm3 can be photopolymerized from the output of a 0.28-mm2 fiber by adding scattering lipid particles while only a volume of 38  mm3 (25%) was achieved without particles. The proposed model provides a simple and robust method to solve complex photopolymerization problems, where the dimension of the light source is much smaller than the volume of the photopolymerizable hydrogel.

The role of a Mediterranean diet on the risk of oral and pharyngeal cancer.

BACKGROUND: The Mediterranean diet has a beneficial role on various neoplasms, but data are scanty on oral cavity and pharyngeal (OCP) cancer. METHODS: We analysed data from a case-control study carried out between 1997 and 2009 in Italy and Switzerland, including 768 incident, histologically confirmed OCP cancer cases and 2078 hospital controls. Adherence to the Mediterranean diet was measured using the Mediterranean Diet Score (MDS) based on the major characteristics of the Mediterranean diet, and two other scores, the Mediterranean Dietary Pattern Adherence Index (MDP) and the Mediterranean Adequacy Index (MAI). RESULTS: We estimated the odds ratios (ORs), and the corresponding 95% confidence intervals (CI), for increasing levels of the scores (i.e., increasing adherence) using multiple logistic regression models. We found a reduced risk of OCP cancer for increasing levels of the MDS, the ORs for subjects with six or more MDS components compared with two or less being 0.20 (95% CI 0.14-0.28, P-value for trend <0.0001). The ORs for the highest vs the lowest quintile were 0.20 (95% CI 0.14-0.28) for the MDP score (score 66.2 or more vs less than 57.9), and 0.48 (95% CI 0.33-0.69) for the MAI score (score value 2.1 or more vs value less 0.92), with significant trends of decreasing risk for both scores. The favourable effect of the Mediterranean diet was apparently stronger in younger subjects, in those with a higher level of education, and in ex-smokers, although it was observed in other strata as well. CONCLUSIONS: Our study provides strong evidence of a beneficial role of the Mediterranean diet on OCP cancer.

A phase I pharmacokinetic study of hypoxic abdominal stop-flow perfusion with gemcitabine in patients with advanced pancreatic cancer and refractory malignant ascites

PURPOSE: As no curative treatment for advanced pancreatic and biliary cancer with malignant ascites exists, new modalities possibly improving the response to available chemotherapies must be explored. This phase I study assesses the feasibility, tolerability and pharmacokinetics of a regional treatment of gemcitabine administered in escalating doses by the stop-flow approach to patients with advanced abdominal malignancies (adenocarcinoma of the pancreas, n = 8, and cholangiocarcinoma of the liver, n = 1). EXPERIMENTAL DESIGN: Gemcitabine at 500, 750 and 1,125 mg/m(2) was administered to three patients at each dose level by loco-regional chemotherapy, using hypoxic abdominal stop-flow perfusion. This was achieved by an aorto-caval occlusion by balloon catheters connected to an extracorporeal circuit. Gemcitabine and its main metabolite 2',2'-difluorodeoxyuridine (dFdU) concentrations were measured by high performance liquid chromatography with UV detection in the extracorporeal circuit during the 20 min of stop-flow perfusion, and in peripheral plasma for 420 min. Blood gases were monitored during the stop-flow perfusion and hypoxia was considered stringent if two of the following endpoints were met: pH </= 7.2, pO(2) nadir ratio </=0.70 or pCO(2) peak ratio >/=1.35. The tolerability of this procedure was also assessed. RESULTS: Stringent hypoxia was achieved in four patients. Very high levels of gemcitabine were rapidly reached in the extracorporeal circuit during the 20 min of stop-flow perfusion, with C (max) levels in the abdominal circuit of 246 (+/-37%), 2,039 (+/-77%) and 4,780 (+/-7.3%) mug/ml for the three dose levels 500, 750 and 1,125 mg/m(2), respectively. These C (max) were between 13 (+/-51%) and 290 (+/-12%) times higher than those measured in the peripheral plasma. Similarly, the abdominal exposure to gemcitabine, calculated as AUC(t0-20), was between 5.5 (+/-43%) and 200 (+/-66%)-fold higher than the systemic exposure. Loco-regional exposure to gemcitabine was statistically higher in presence of stringent hypoxia (P < 0.01 for C (max) and AUC(t0-20), both normalised to the gemcitabine dose). Toxicities were acceptable considering the complexity of the procedure and were mostly hepatic; it was not possible to differentiate the respective contributions of systemic and regional exposures. A significant correlation (P < 0.05) was found between systemic C (max) of gemcitabine and the nadir of both leucocytes and neutrophils. CONCLUSIONS: Regional exposure to gemcitabine-the current standard drug for advanced adenocarcinoma of the pancreas-can be markedly enhanced using an optimised hypoxic stop-flow perfusion technique, with acceptable toxicities up to a dose of 1,125 mg/m(2). However, the activity of gemcitabine under hypoxic conditions is not as firmly established as that of other drugs such as mitomycin C, melphalan or tirapazamine. Further studies of this investigational modality, but with bioreductive drugs, are therefore warranted first to evaluate the tolerance in a phase I study and later on to assess whether it does improve the response to chemotherapy.