1,245 research outputs found
The submarine hydrothermal system of Panarea (Southern Italy): biogeochemical processes at the thermal fluids - sea bottom interface
Among the submarine hydrothermal systems located offshore the volcanic archipelago of the
Aeolian Islands (Southern Italy), the most active is located off the coasts of Panarea island. Thermal
waters, gases and sulfur deposits coexist at the sea bottom where hydrothermal fluids are released
from both shallow and deep vents. The chemical and isotopic composition of the fluid phase shows
the presence of a significant magmatic component and the physico-chemical conditions of the
geothermal reservoir allow the release of reduced chemical species that are microbially mediated
towards the production of organic carbon as a form of biochemical energy. Microorganisms
inhabiting this environment possess nutritional requirements and overall metabolic pathways ideally
suited to such ecosystem that represents a clear example of the close connection between geosphere
and biosphere. Microscopic examination of the white mat attached to rock surfaces showed the
presence of Thiothrix-like filamentous bacteria. Moderately thermophilic heterotrophic isolates
were identified as strains of the genus Bacillus. Although the hydrothermal system of Panarea has
to be considered a “shallow” system, it shows many characteristics that make it similar to the
“deep” oceanic systems, giving a unique opportunity for improving our knowledge on such an
unexplored world by working at this easily accessible site
Aulogous fibrin sealant (Vivostat®) in the neurosurgical practice: Part II: Vertebro-spinal procedures
Background: Epidural hematomas, cerebrospinal fluid fistula, and spinal infections are challenging postoperative complications following vertebro-spinal procedures. We report our preliminary results using autologous fibrin sealant as both fibrin glue and a hemostatic during these operations. Methods: Prospectively, between January 2013 and March 2015, 68 patients received an autologous fibrin sealant prepared with the Vivostat®system applied epidurally to provide hemostasis and to seal the dura. The surgical technique, time to bleeding control, and associated complications were recorded. Results: Spinal procedures were performed in 68 patients utilizing autologous fibrin glue/Vivostat®to provide rapid hemostasis and/or to seal the dura. Only 2 patients developed postoperative dural fistulas while none exhibited hemorrhages, allergic reactions, systemic complications, or infections. Conclusions: In this preliminary study, the application of autologous fibrin sealant with Vivostat®resulted in rapid hemostasis and/or acted as an effective dural sealant. Although this product appears to be safe and effective, further investigations are warranted
Reconstruction of daily pressure maps over Italy during some extreme events of the 19th Century
The quality and availability of daily meteorological data for the reconstruction of atmospheric circulation over Italy in the period between the Italian political Unity (1860) and the development of the Central Office for Meteorology (1879) is studied. Examples of atmospheric circulation reconstructed for some extreme events are presented
Screening and identification of cellulase producing yeast-like microorganisms from Brazilian biomes
The main goals of the present study included the screening and identification of cellulase producing wild yeasts, isolated from samples collected from different Brazilian biomes. They were selected according to their capabilities of degrading carboxymethyl cellulose (CMC) and micro-crystalline cellulose (SERVACEL®), as single carbon sources in solid medium. After the step of solid medium selection, yeast cells were grown in liquid medium containing cellulose (SERVACEL®); in shake flasks at temperature of 30°C and 150 rpm agitation for 288 h. Three specific activities were evaluated: endoglucanase (CMCase), total activity (filter paper activity), and cellobiase. From a total of 390 strains of wild yeasts previously isolated, 16 strains performed cellulose hydrolysis, verified by the colorless halo in the solid medium. Among these 16 strains, 5 stood out as presenting higher levels of enzyme activity. The following step, screening in liquid medium, indicated only one strain as a potential producer of cellulases, named as AAJ6, for which the highest hydrolytic activity on carboxymethyl cellulose (0.33 U/ml) and filter paper (0.039 U/ml) was recorded. Afterwards, this wild yeast strain (AAJ6) was molecularly identified by sequencing the ITS1-5.8S-ITS2 and D1/D2 domains of the subunit (26 S) ribosomal DNA. Sequencing resulted in the identification of this strain as yeast-like fungus Acremonium strictum.Keywords: Acremonium strictum, screening, identification, yeast-like, cellulase
Variability of orographic enhancement of precipitation in the Alpine region
Climate change impacts are non uniformly distributed over the globe. Mountains have a peculiar response to large scale variations, documented by elevation gradients of surface temperature increase observed over many mountain ranges in the last decades. Significant changes of precipitation are expected in the changing climate and orographic effects are important in determining the amount of rainfall at a given location. It thus becomes particularly important to understand how orographic precipitation responds to global warming and to anthropogenic forcing. Here, using a large rain gauge dataset over the European Alpine region, we show that the distribution of annual precipitation among the lowlands and the mountains has varied over time, with an increase of the precipitation at the high elevations compared to the low elevations starting in the mid 20 century and peaking in the 1980s. The simultaneous increase and peak of anthropogenic aerosol load is discussed as a possible source for this interdecadal change. These results provide new insights to further our understanding and improve predictions of anthropic effects on mountain precipitations, which are fundamental for water security and management
Unusual recurrence of trigeminal neuralgia after microvascular decompression by muscle interposal
Background: Patients with trigeminal neuralgia (TN) and persistent or recurrent facial pain after microvascular decompression (MVD) typically undergo less invasive procedures in the hope of providing pain relief. However, re-operation should be considered in selected patients. Case Report: A 48-year-old woman presented with recurrent trigeminal neuralgia (TN) 3 years following microvascular decompression (MVD). The patient underwent brain magnetic resonance angiography (MRA), which did not reveal neurovascular compression; therefore surgical re-exploration was carried out. During the operation, the fifth cranial nerve was seen without impingement from any blood vessels; however, a very firm tissue was observed and identified as the muscle fragment from the previous MVD procedure. The fifth cranial nerve was carefully separated from the muscle. Thereafter, the right SCA was dissected out from the muscle and suspended by a periosteum tape sutured to the nearby dura. Conclusions: Our findings, along with similar cases reported in the literature, support the development of new inert materials and alternative surgical strategies that can limit TN recurrence
Impasse in the management of recurrent basal cell carcinoma of the skull with sagittal sinus erosion1
Abstract Basal cell carcinoma (BCC) is a non melanocytic skin cancer that arises from basal cells, affecting commonly fair-skinned human beings. Although the tumor is well known for local recurrences, extension into the intracranial space is reported. A case of a giant BCC of the scalp invading the middle and posterior third of the superior sagittal sinus (SSS) is reported. A 70-year-old male with a basal cell carcinoma history presented with a massive bleeding from the SSS invaded by the tumor. Since the patient refused surgery the bleeding was managed through direct compression by applying a thrombin-based hemostatic agents and sterile dressings. This procedure was performed daily in order to stimulate the spontaneous thrombosis of the dural sinus and development of collateral circle. BCC invading the SSS is rarely reported. A technical description of this case is provided. This case underscores the importance of early and appropriate treatment for high risk BCC, and whenever surgical procedure is not suitable appropriate conservative treatment may be efficacious
The mobility of Atlantic baric depressions leading to intense precipitation over Italy: a preliminary statistical analysis
International audienceThe speed of Atlantic surface depressions, occurred during the autumn and winter seasons and that lead to intense precipitation over Italy from 1951 to 2000, was investigated. Italy was divided into 5 regions as documented in previous climatological studies (based on Principal Component Analysis). Intense precipitation events were selected on the basis of in situ rain gauge data and clustered according to the region that they hit. For each intense precipitation event we tried to identify an associated surface depression and we tracked it, within a large domain covering the Mediterranean and Atlantic regions, from its formation to cyclolysis in order to estimate its speed. "Depression speeds" were estimated with 6-h resolution and clustered into slow and non-slow classes by means of a threshold, coinciding with the first quartile of speed distribution and depression centre speeds were associated with their positions. Slow speeds occurring over an area including Italy and the western Mediterranean basin showed frequencies higher than 25%, for all the Italian regions but one. The probability of obtaining by chance the observed more than 25% success rate was estimated by means of a binomial distribution. The statistical reliability of the result is confirmed for only one region. For Italy as a whole, results were confirmed at 95% confidence level. Stability of the statistical inference, with respect to errors in estimating depression speed and changes in the threshold of slow depressions, was analysed and essentially confirmed the previous results
Delayed chronic intracranial subdural hematoma complicating resection of a tanycytic thoracic ependymoma
Background: To demonstrate that the diagnosis of an intracranial subdural hematoma should be considered for patients presenting with acute or delayed symptoms of intracranial pathology following resection of a spinal tumor. Case Description: We present a case of a 57-year-old woman found to have a chronic subdural hematoma 1 month following resection of a thoracic extramedullary ependymoma. Evacuation of the hematoma through a burr hole relieved the presenting symptoms and signs. Resolution of the hematoma was confirmed with a computed tomography (CT) scan. Conclusion: Headache and other symptoms not referable to spinal pathology should be regarded as a warning sign of an intracranial subdural hematoma, and a CT scan of the head should be obtained. The mechanism of the development of the hematoma may be related to the leakage of cerebrospinal fluid with subsequent intracranial hypotension leading to an expanding subdural space and hemorrhage
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