In Navier-Stokes turbulence, energy and helicity injected at large scales are subject to a joint direct cascade, with both quantities exhibiting a spectral scaling ∝k^{-5/3}. We demonstrate via direct numerical simulations that the two cascades are compatible due to the existence of a strong scale-dependent phase alignment between velocity and vorticity fluctuations, with the phase alignment angle scaling as cosα_{k}∝k^{-1}.
View Article and Find Full Text PDFMicroalgal oils (AOs) emerged recently as an alternative to fish oil and to nutritionally poorer vegetable oils for fish species. In this trial, two experimental diets containing fish oil (negative control: 2.1%; positive control: 13.
View Article and Find Full Text PDFIn weakly collisional plasma environments with sufficiently low electron beta, Alfvénic turbulence transforms into inertial Alfvénic turbulence at scales below the electron skin depth, k_{⊥}d_{e}≳1. We argue that, in inertial Alfvénic turbulence, both energy and generalized kinetic helicity exhibit direct cascades. We demonstrate that the two cascades are compatible due to the existence of a strong scale dependence of the phase alignment angle between velocity and magnetic field fluctuations, with the phase alignment angle scaling as cosα_{k}∝k_{⊥}^{-1}.
View Article and Find Full Text PDFObjective: Surgical treatment of orbital lesions is challenging because complex approaches with a high risk of postoperative sequelae are required. Recently, minimally invasive endoscopic approaches through endonasal (EEA) and transpalpebral (ETP) routes have been proposed. The objective of this study was to assess outcomes of EEA and ETP in the authors' series of patients with orbital lesions.
View Article and Find Full Text PDFActa Neurochir (Wien)
December 2018
Introduction: Recently, an alternative endoscopic endonasal approach to Meckel's cave (MC) tumors has been proposed. To date, few studies have evaluated the results of this route. The aim of our study was to evaluate long-term surgical and clinical outcome associated with this technique in a cohort of patients with intrinsic MC tumors.
View Article and Find Full Text PDFBackground: Radiation therapy (RT) effectiveness on hormonal reduction is proven in acromegaly; however, collateral long-term effects are still undetermined. This transversal neuroimaging study on a large cohort of acromegalic patients aimed to investigate the rate of parenchymal and vascular changes after RT.
Materials And Methods: Thirty-six acromegalic patients underwent RT (RT+) after unsuccessful surgery and were compared to RT- acromegalic patients matched for age, gender, adenoma features, clinical and surgical history.
This study aimed to quantify 24h body core temperature (BcT°) and sleep-wake cycle rhythm alterations in craniopharyngioma (CP) patients and to identify markers related to the postsurgical outcomes. Ten consecutive CP patients underwent neuroradiological, endocrinological and ophthalmological evaluations, 24h BcT° and sleep-wake cycle recordings before and after endoscopic endonasal surgery. The sample included four women and six men.
View Article and Find Full Text PDFObjective: Postoperative infection is a potentially dramatic consequence in endoscopic endonasal surgery. The aim of this study was to assess the efficacy of our intraoperative antibiotic prophylaxis by analyzing the risk factors of postoperative meningitis in our series.
Methods: Each endoscopic endonasal procedure performed since 1998 in patients with no preoperative infections and a follow-up longer than 30 days were included and retrospectively reviewed.
Background: The optimal management of pituitary apoplexy (PA) remains debated. The aim of this study was to assess the outcome of the transsphenoidal approach for PA in a large surgical experience.
Materials: Each consecutive case of PA consecutively operated by endoscopic endonasal approach from our tertiary care center, from 1998 to 2015, was included in this series.
OBJECTIVE In the past decade, the role of the endoscopic endonasal approach (EEA) has relevantly evolved for skull base tumors. In this study, the authors review their surgical experience with using an EEA in the treatment of clival chordomas, which are deep and infiltrative skull base lesions, and they highlight the advantages and limitations of this ventral approach. METHODS All consecutive cases of chordoma treated with an EEA between 1998 and 2015 at a single institution are included in this study.
View Article and Find Full Text PDFCR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks.
View Article and Find Full Text PDFA compact neutron spectrometer, based on a CH foil for the production of recoil protons and CR-39 detection, is being developed for the measurements of the DD-neutron spectrum at the NIF, OMEGA, and Z facilities. As a CR-39 detector will be used in the spectrometer, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). To reject the background to the required level for measurements of the down-scattered and primary DD-neutron components in the spectrum, the Coincidence Counting Technique (CCT) must be applied to the data.
View Article and Find Full Text PDFOBJECTIVE One of the more serious risks in the treatment of third ventricle craniopharyngiomas is represented by hypothalamic damage. Recently, many papers have reported the expansion of the indications for the endoscopic endonasal approach (EEA) to be used for these tumors as well. The aim of this study was to assess the outcome of sleep-wake cycle and body core temperature (BCT), both depending on hypothalamic control, in patients affected by craniopharyngiomas involving the third ventricle that were surgically treated via an EEA.
View Article and Find Full Text PDFBackground: The collection of the greatest possible amount of pathologic tissue is of paramount importance in neurosurgery to achieve the most accurate histopathologic diagnosis, to perform all of the necessary biomolecular tests on the pathologic specimen, and to collect biological material for basic or translational science studies. This problem is particularly relevant in pituitary surgery because of the possible small size and soft consistency of tumors, which make them suitable for removal through suction, reducing the amount of available pathologic tissue. To solve this issue, we adopted a filter connected to the suction tube, which allows the surgeon to collect all of the tissue aspirated during surgery.
View Article and Find Full Text PDFBackground: Cavernous sinus (CS) invasion is one of the most unfavorable features of pituitary adenomas. The most widely used classification was proposed by Knosp in 1993 and revised in 2015. The aim of this study is to extend our previous experience by comparing the pre-operative neuroradiological assessment with the intra-operative endoscopic endonasal inspection in order to evaluate the real rate of CS invasion and analyze its correlation with the surgical outcome.
View Article and Find Full Text PDFA remote cerebellar hemorrhage (RCH) is a spontaneous bleeding in the posterior fossa, which may rarely occurs as a complication of supratentorial procedures, and it shows a typical bleeding pattern defined "the zebra sign." However, its pathophysiology still remains unknown. We performed a comprehensive review collecting all cases of RCH after supratentorial craniotomies reported in literature in order to identify the most frequently associated procedures and the possible risk factors.
View Article and Find Full Text PDFA remote cerebellar hemorrhage (RCH) is a spontaneous bleeding in the posterior fossa, which can be rarely observed as a complication of spine surgery. As well as for RCH reported after supratentorial procedures, it shows a characteristic bleeding pattern defined "zebra sign". Nowadays, RCH pathophysiology still remains unknown.
View Article and Find Full Text PDFBackground: Intraparenchymal cavities communicating with the ventricles may appear in patients with chronic obstructive hydrocephalus despite no identifiable surgerical, vascular or traumatic causes. The rate, features, pathogenesis, evolution and clinical impact of intraparenchymal diverticula have not been outlined, yet.
Methods: Brain MRIs of 130 patients (mean age: 11.
Introduction: Cerebrospinal fluid (CSF) rhinorrhea can lead to CNS infections, carrying significant morbidity and mortality, especially in the elderly. Endoscopic endonasal surgery is a validated technique in the repair of anterior skull base CSF leaks. The aim of this study is to assess diagnostic management, surgical technique and clinical outcome in a consecutive series of elderly patients.
View Article and Find Full Text PDFAggressive pituitary adenomas (PAs) are clinically challenging for endocrinologists and neurosurgeons due to their locally invasive nature and resistance to standard treatment (surgery, medical or radiotherapy). Two pituitary-directed drugs have recently been proposed: temozolomide (TMZ) for aggressive PA, and pasireotide for ACTH-secreting PA. We describe the experience of our multidisciplinary team of endocrinologists, neurosurgeons, neuroradiologists, oncologists, otolaryngologists and pathologists with TMZ and pasireotide treatment for aggressive PAs in terms of their radiological shrinkage and genetic features.
View Article and Find Full Text PDFPurpose: Although cerebrovascular mortality is increased up to eightfold in acromegaly, intracranial internal carotid artery (ICA) changes have not been well investigated. This is a magnetic resonance angiography (MRA) quantitative cross-sectional study of ICA tortuosity, ectasia and intercarotid distance in acromegalic patients with subsequent analysis of concomitant clinical, laboratory and neuroimaging findings.
Methods: One hundred seventy six acromegalic patients (mean-age 55 ± 14 years, age range 21-88, 92 females) and 104 subjects with headache or transient neurological deficits underwent MRA with the same 1.
Introduction: Ischemic brain lesions might present with unexpected increased signal intensity at MR angiography within the ischemic lesion and secondary parenchymal changes in regions distal to the ischemia itself. We retrospectively investigated the rate and time course of vascular and parenchymal changes in children with isolated middle cerebral artery (MCA) stroke.
Methods: Twelve children (mean age at stroke onset 4.
Hydranencephaly is a severe congenital condition where most of the cerebral hemispheres are replaced by a membranous sac. Despite the growing amount of case reports, most pathogenic, phenotypic, and prognostic aspects of hydranencephaly remain controversial. By matching the recent literature data with the findings of our own series (four cases: two fetuses at the twelfth gestational week, a 32-year-old man, and a 14-year-old female), we attempted to date back the insult leading to hydranencephaly to understand its pathogenesis and to explain the basis of its protean phenotype.
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