53 research outputs found
Generalized ballistic-conductive heat conduction in isotropic materials
The general isotropic constitutive equations of heat conduction with second
sound and ballistic propagation in isotropic materials is given using
Non-Equilibrium Thermodynamics with Internal Variables (NET-IV). The
consequences of Onsager reciprocity between thermodynamic fluxes and forces and
positive definiteness of the entropy production is considered. The relation to
theories of Extended Thermodynamics is discussed in detail.Comment: 22 pages, no figure
Case Report Usefulness of Image Guidance in the Surgical Treatment of Petrous Apex Cholesterol Granuloma
The petrous apex is a pyramid-shaped structure, located medial to the inner ear and the intrapetrous segment of the internal carotid artery. Lesions of the petrous apex can be surgically treated through different surgical routes. Because of the important neurovascular structures located inside the temporal bone, anatomical 3D knowledge is paramount. For this reason, image-guided surgery could represent a useful tool. We report the case of a young woman who came to our observation for a trigeminal neuralgia due to a petrous apex cholesterol granuloma. The lesion was treated through the placement of a drainage tube via an infracochlear approach, with the aid of neuronavigation and intraoperative MRI. Preoperative CT scan images and intraoperative MRI images were fused for surgical planning. The accuracy of the neuronavigation system has proved to be good, and the safety of the procedure was enhanced. Therefore, neuronavigation and intraoperative MRI, though not available in all neurootological centres, should be considered useful tools in these challenging procedures
Performance of Delta4 Phantom+ using Flattening-Filter and Flattening Filter-Free beams
EnThe goal of this study was to evaluate the performances of the new pre-treatment system Delta4 Phantom+ in terms of a stable and sensitive tool for achieving a reliable verification. Delta4+ was evaluated for verification with 6FFFMV beams using static beam arrangement. The accelerator output was monitored with the ionization chamber. The device was tested for dose-rate dependence, linearity and stability using its daily output correction. The response of Delta4+ was evaluated for energy 6FFFMV, measuring the gamma index of four Volumetric Modulated Arc Therapy (VMAT) plan. The response of Delta4+ as a function of accelerator dose rate is in agreement with the ionization chamber with a difference smaller than 0,1%. The output is constant for different MU. VMAT plan analysis show values within 98,3%-100% with a threshold of 3%-3mm, while with a threshold of 2%-2mm the values are within 93,5%-97,5%. Delta4+ is an accurate device. For all the measurements made, uncertainties below 1% were obtained.ItLo scopo di questo studio è stato quello di valutare la risposta in termini di stabilità e sensibilità del nuovo sistema pre-trattamento Delta4 Phantom+. La risposta del sistema è stato studiata utilizzando fasci di fotoni da 6MVsenza filtro di flattening (6FFFMV). L'output dell'acceleratore è stato monitorato con una camera a ionizzazione. La dipendenza dal dose rate, la linearità e la stabilità sono state verificate utilizzando il fattore di correzione giornaliera fornito dal sistema. La risposta è stata verificata su 4 piani di trattamento con tecnica VMAT. La risposta del Delta4+ al variare del dose rate è in accordo con quella della camera a ionizzazione con una scarto minore dello 0.1%. La risposta al variare delle UM è costante con una differenza entro lo 0.4%. L'analisi dei piani VMAT mostra valori di indice gamma per soglia 3%-3mm compresi tra 98.3%-100%, mentre per 2%-2mm i valori sono tra 93,5%-97,5%. Il Delta4+ risulta essere un sistema accurato in quanto l'incertezza ottenuta su tutte le misure non supera l'1%
Traumatic Pseudoaneurysm of the Internal Maxillary Artery: A Rare Life-Threatening Hemorrhage as a Complication of Maxillofacial Fractures
Pseudoaneurysm of the internal maxillary artery due to a traumatic event is a rare condition. Pseudoaneurysms are usually directly produced by arteries break with extravasation of blood. The compressed perivascular tissue forms the wall of aneurysmal sac. Then, this sac gradually expands and can be damaged. It is rare to see pseudoaneurysms of IMA. They are usually associated with fracture of the neck of the mandible. To the best of our knowledge the pseudoaneurysm of the internal maxillary artery related to maxillofacial trauma is an event extremely rare in the literature and if not quickly managed can lead to the patientâs death. This case underlines how the close cooperation between surgeons and radiologists results in a quick diagnosis and management of such pathological events
Validation of the REM behaviour disorder phenoconversion-related pattern in an independent cohort
Background: A brain glucose metabolism pattern related to phenoconversion in patients with idiopathic/isolated REM sleep behaviour disorder (iRBDconvRP) was recently identified. However, the validation of the iRBDconvRP in an external, independent group of iRBD patients is needed to verify the reproducibility of such pattern, so to increase its importance in clinical and research settings. The aim of this work was to validate the iRBDconvRP in an independent group of iRBD patients. Methods: Forty iRBD patients (70 Âą 5.59Â years, 19 females) underwent brain [18F]FDG-PET in Seoul National University. Thirteen patients phenoconverted at follow-up (7 Parkinson disease, 5 Dementia with Lewy bodies, 1 Multiple system atrophy; follow-up time 35 Âą 20.56Â months) and 27 patients were still free from parkinsonism/dementia after 62 Âą 29.49Â months from baseline. We applied the previously identified iRBDconvRP to validate its phenoconversion prediction power. Results: The iRBDconvRP significantly discriminated converters from non-converters iRBD patients (p = 0.016; Area under the Curve 0.74, Sensitivity 0.69, Specificity 0.78), and it significantly predicted phenoconversion (Hazard ratio 4.26, C.I.95%: 1.18â15.39). Conclusions: The iRBDconvRP confirmed its robustness in predicting phenoconversion in an independent group of iRBD patients, suggesting its potential role as a stratification biomarker for disease-modifying trials.</p
Internal Transcribed Spacer 2 (nu ITS2 rRNA) Sequence-Structure Phylogenetics: Towards an Automated Reconstruction of the Green Algal Tree of Life
L). Some have advocated the use of the nuclear-encoded, internal transcribed spacer two (ITS2) as an alternative to the traditional chloroplast markers. However, the ITS2 is broadly perceived to be insufficiently conserved or to be confounded by introgression or biparental inheritance patterns, precluding its broad use in phylogenetic reconstruction or as a DNA barcode. A growing body of evidence has shown that simultaneous analysis of nucleotide data with secondary structure information can overcome at least some of the limitations of ITS2. The goal of this investigation was to assess the feasibility of an automated, sequence-structure approach for analysis of IT2 data from a large sampling of phylum Chlorophyta.Sequences and secondary structures from 591 chlorophycean, 741 trebouxiophycean and 938 ulvophycean algae, all obtained from the ITS2 Database, were aligned using a sequence structure-specific scoring matrix. Phylogenetic relationships were reconstructed by Profile Neighbor-Joining coupled with a sequence structure-specific, general time reversible substitution model. Results from analyses of the ITS2 data were robust at multiple nodes and showed considerable congruence with results from published phylogenetic analyses.Our observations on the power of automated, sequence-structure analyses of ITS2 to reconstruct phylum-level phylogenies of the green algae validate this approach to assessing diversity for large sets of chlorophytan taxa. Moreover, our results indicate that objections to the use of ITS2 for DNA barcoding should be weighed against the utility of an automated, data analysis approach with demonstrated power to reconstruct evolutionary patterns for highly divergent lineages
Experimental study of the methane steam reforming reaction in a dense Pd/ Ag membrane reactor
The reaction of methane steam reforming was carried out in both a traditional reactor (TR) and a membrane reactor (MR). The membrane consisted of a 50-Âľm-thick pinhole-free palladium/ silver alloy. To investigate the enhancement of the methane conversion in the steam reforming reaction in an MR, the effects of various kinds of sweep gas (hydrogen, nitrogen, carbon monoxide, air, oxygen, and steam), as well as no sweep gas, were analyzed as a function of temperature at different molar flow rates of the sweep gas used. The dependence of the methane conversion on increasing H2O/CH 4 feed ratio was also studied. Experimental results in terms of methane conversion for the MR were compared with those obtained using a TR and literature data
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