407 research outputs found

    Atrial assist device, a new alternative to lifelong anticoagulation?

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    OBJECTIVE: Atrial fibrillation is a very common heart arrhythmia, associated with a five-fold increase in the risk of embolic strokes. Treatment strategies encompass palliative drugs or surgical procedures all of which can restore sinus rhythm. Unfortunately, atria often fail to recover their mechanical function and patients therefore require lifelong anticoagulation therapy. A motorless volume displacing device (Atripump) based on artificial muscle technology, positioned on the external surface of atrium could avoid the need of oral anticoagulation and its haemorrhagic complications. An animal study was conducted in order to assess the haemodynamic effects that such a pump could provide. METHODS: Atripump is a dome-shape siliconecoated nitinol actuator sewn on the external surface of the atrium. It is driven by a pacemaker-like control unit. Five non-anticoagulated sheep were selected for this experiment. The right atrium was surgically exposed, the device sutured and connected. Haemodynamic parameters and intracardiac ultrasound (ICUS) data were recorded in each animal and under three conditions; baseline; atrial fibrillation (AF); atripump assisted AF (aaAF). RESULTS: In two animals, after 20 min of AF, small thrombi appeared in the right atrial appendix and were washed out once the pump was turned on. Assistance also enhanced atrial ejection fraction. 31% baseline; 5% during AF; 20% under aaAF. Right atrial systolic surfaces (cm2) were; 5.2 +/- 0.3 baseline; 6.2 +/- 0.1 AF; 5.4 +/- 0.3 aaAF. CONCLUSION: This compact and reliable pump seems to restore the atrial "kick" and prevents embolic events. It could avoid long-term anticoagulation therapy and open new hopes in the care of end-stage heart failure

    Deep electrical resistivity tomography and geothermal analysis of Bradano foredeep deposits in Venosa area (Southern Italy): preliminary results

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    Geophysical surveys have been carried out to characterize the stratigraphical and structural setting and to better understand the deep water circulation system in the Venosa area (Southern Italy) located in the frontal portion of the southern Appenninic Subduction. In this area there are some deep water wells from which a water conductivity of about 3 mS/cm and a temperature of about 35°C was measured. A deep geoelectrical tomography with dipole-dipole array has been carried out along a profile of 10000 m and an investigation depth of about 900 m. Furthermore a broad band magnetotelluric profile consisting of six stations was performed to infer the resistivity distribution up to some kilometres of depth. The MT profile was almost coincident with the geoelectrical outline. The applied methods allow us to obtain a mutual control and integrated interpretation of the data. The high resolution of the data was the key to reconstruct the structural asset of buried carbonatic horst whose top is located at about 600 m depth. The final results coming from data wells, geothermal analysis and geophysical data, highlighted a horst saturated with salted water and an anomalous local gradient of 60°C/km. The proposed mechanism is that of a mixing of fossil and fresh water circulation system

    Endoscopic access closure for direct implantation of valved stents

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    OBJECTIVES: The off-pump trans left ventricular approach provides an alternative option for insertion of stented aortic valves of any size for endovascular replacement. One of the key steps in this procedure is the repair of the ventricle after catheter withdrawal. This study evaluates the reliability of a new device for sutureless and quick repair of the left ventricle access. METHODS: The Amplatz-nitinol occluder consists of two square heads that squeeze the ventricle wall between them thus sealing the ventricular defect. In four adult pigs weighing 55 kg, left thoracoscopy was performed to open the pericardium and visualise the cardiac apex. Following a heparin injection (100 U/kg) under ICUS and fluoroscopic control, we inserted a 30 F sheath into the epigastric area through the cardiac apex up into the left ventricle thus simulating the approach for an off-pump aortic valve replacement. The sheath was then removed and the ventricle closed with the occluder. Animals were followed-up for three hours; the haemodynamics and pericardial bleeding were recorded. The animals were then sacrificed and the gross anatomy of the heart was examined. RESULTS: The device was successfully deployed in four animals in less than one minute. ACT was above 200 seconds in all cases. All animals survived the procedure with a mean arterial pressure of 50 +/- 15 mm Hg. Bleeding during deployment was 80 +/- 20 ml and over a 3 hour period was 800 +/- 20 ml. Examination of the gross anatomy examination demonstrated the correct positioning of the device. CONCLUSIONS: The occluder is easy to use and the procedure is feasible and reproducible. However, the occluder design requires technical improvements in order to reduce bleeding before it can be used clinically

    microRNA-377-3p downregulates the oncosuppressor T-cadherin in colorectal adenocarcinoma cells

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    Colorectal cancer (CRC) is the second leading cause of death of malignant tumors worldwide. Recent studies point to a role for the adiponectin-receptor axis in colorectal carcinogenesis, and in particular to the oncosuppressive properties of the T-cadherin receptor. In addition, the loss of T-cadherin expression in tumor tissues has been linked to cancer progression and attributed to aberrant methylation of its promoter. Recognizing the pivotal role of microRNAs in CRC, this study explores their possible contribution to the downregulation of T-cadherin. A systematic bioinformatics analysis, restricted by microRNA expression data in the colon or in cultured colorectal cell lines, predicted twelve top-ranking target miRNA sites within the 3ʹ UTR of T-cadherin. Experimental validation analyses based on luciferase reporter constructs and miRNA mimic or miRNA inhibitor transfections toward colorectal adenocarcinoma cell lines indicated that miR-377-3p was able to directly bind to the T-cadherin sequence, and thus downregulating its expression. Given the oncogenic activity of miR-377 and the oncosuppressive activity of T-cadherin in CRC, the regulatory circuit highlighted in this study may add new insights into molecular mechanisms driving colorectal carcinogenesis, and perspectively it could be exploited to identify novel biomarkers and therapeutic targets

    Buried volcanic structures in the Gulf of Naples (Southern Tyrrhenian Sea, Italy) resulting from high resolution magnetic survey and seismic profiling

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    In this paper we present a correlation between volcanic structures and magnetic anomalies in the Gulf of Naples (Southern Tyrrhenian Sea) based on high resolution magnetic profiling. A densely spaced grid of magnetic profiles coupled with multichannel seismics (seismic source Watergun 15 cubic inch) was recorded in the Gulf of Naples, representing an active volcanic area during the Late Quaternary (volcanic centers of Somma-Vesuvius, Phlegraean Fields and Ischia and Procida islands). The dataset was collected during the oceanographic cruise GMS00-05 which took place during October-November 2000 in the South Tyrrhenian Sea onboard of the R/V Urania (National Research Council, Italy). Shallow volcanic structures in the subsurface of the gulf were recognized by seismo-stratigraphic analysis of high resolution profiles; the volcanic nature of some of these structures was inferred identifying the magnetic anomalies on a high resolution magnetic anomaly map of the gulf. Even if qualitative, the correlations between seismic and magnetic profiles allow us to better assess the geological structure of the Gulf of Naples

    HyPoradise: An Open Baseline for Generative Speech Recognition with Large Language Models

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    Advancements in deep neural networks have allowed automatic speech recognition (ASR) systems to attain human parity on several publicly available clean speech datasets. However, even state-of-the-art ASR systems experience performance degradation when confronted with adverse conditions, as a well-trained acoustic model is sensitive to variations in the speech domain, e.g., background noise. Intuitively, humans address this issue by relying on their linguistic knowledge: the meaning of ambiguous spoken terms is usually inferred from contextual cues thereby reducing the dependency on the auditory system. Inspired by this observation, we introduce the first open-source benchmark to utilize external large language models (LLMs) for ASR error correction, where N-best decoding hypotheses provide informative elements for true transcription prediction. This approach is a paradigm shift from the traditional language model rescoring strategy that can only select one candidate hypothesis as the output transcription. The proposed benchmark contains a novel dataset, “HyPoradise” (HP), encompassing more than 334, 000 pairs of N-best hypotheses and corresponding accurate transcriptions across prevalent speech domains. Given this dataset, we examine three types of error correction techniques based on LLMs with varying amounts of labeled hypotheses-transcription pairs, which gains a significant word error rate (WER) reduction. Experimental evidence demonstrates the proposed technique achieves a breakthrough by surpassing the upper bound of traditional re-ranking based methods. More surprisingly, LLM with reasonable prompt and its generative capability can even correct those tokens that are missing in N-best list. We make our results publicly accessible for reproducible pipelines with released pre-trained models, thus providing a new evaluation paradigm for ASR error correction with LLMs

    Engineering solution-processed non-crystalline solid electrolytes for Li Metal batteries

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    Non-crystalline Li-ion solid electrolytes (SEs), such as lithium phosphorus oxynitride, can uniquely enable high-rate solid-state battery operation over thousands of cycles in thin film form. However, they are typically produced by expensive and low throughput vacuum deposition, limiting their wide application and study. Here, we report non-crystalline SEs of composition Li–Al–P–O (LAPO) with ionic conductivities > 10–7 S cm–1 at room temperature made by spin coating from aqueous solutions and subsequent annealing in air. Homogenous, dense, flat layers can be synthesized with submicrometer thickness at temperatures as low as 230 °C. Control of the composition is shown to significantly affect the ionic conductivity, with increased Li and decreased P content being optimal, while higher annealing temperatures result in decreased ionic conductivity. Activation energy analysis reveals a Li-ion hopping barrier of ≈0.4 eV. Additionally, these SEs exhibit low room temperature electronic conductivity (< 10–11 S cm–1) and a moderate Young’s modulus of ≈54 GPa, which may be beneficial in preventing Li dendrite formation. In contact with Li metal, LAPO is found to form a stable but high impedance passivation layer comprised of Al metal, Li–P, and Li–O species. These findings should be of value when engineering non-crystalline SEs for Li-metal batteries with high energy and power densities

    Gefäßchirurgische Ausbildung in endovaskulärer Technik in Lausanne

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    Zusammenfassung: Zwischen 1995 und 2005 wuchs die Anzahl der jährlich von uns mit endovaskulären Techniken versorgten Aortenaneurysmen (EVAR) von 0 auf 50, und dies auf allen Stufen der Aorta. Zu unserer Organisation gehören ein breites Team von Chirurgen, ein Lager mit 3kompletten Familien von Endoprothesen (gerade Endoprothesen, konische Endoprothesen, und Bifurkationen), ein mobiler Wagen mit Zubehör (Einführungsbestecke, Führungsdrähte, Katheter, Ballone etc.) und ein Apparat auf Rädern für die intravaskuläre Ultraschalluntersuchung (IVUS). Letzterer erlaubt es zusammen mit einer mobilen Durchleuchtungsanlage (C-Bogen), in jedem Operationssaal unserer Institution endovaskulär Aneurysmen zu analysieren, und dies in der Regel ohne Angiographie bzw. Kontrastmittel. Deshalb sind wir nicht mehr auf eine ausgiebige bildgebende präoperative Abklärung potenzieller Kandidaten für eine endovaskuläre Sanierung von Aneurysmen angewiesen und können rupturierte Aneurysmen der Bauchaorta oder der thorakalen Aorta ohne Verzug behandeln. Bei der endovaskulären Sanierung von Aortenaneurysmen unterscheiden wir zwischen Prozessschritten (Indikationsstellung, Darstellung der Zugangsgefäße, Ausmessen mittels IVUS und Roadmapping mittels Durchleuchtung, Implantatwahl, Implantatinsertion, Positionierung, Implantatabwurf, Erfolgsbeurteilung, Rekonstruktion der Zugangsgefäße und Nachkontrolle) und Kompetenzstufen (Assistent, Oberarzt, Leitender Arzt). Unsere ultraschallgestützte Technik zur endovaskulären Sanierung von Aneurysmen wurde mittels IVUS-Transporter und Telementoring erfolgreich auch anderen Institutionen zur Verfügung gestell

    Using the ERT method in tectonically active areas: hints from Southern Apennine (Italy)

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    Electrical Resistivity Tomography (ERT) method has been used to study two tectonically active areas of southern Apennine (Caggiano Faults and Ufita Basin). The main aim of this job was to study the structural setting of the investigated areas, i.e. the geometry of the basins at depth, the location of active faults at surface, and their geometrical characterization. The comparison between ERT and trench/drilling data allowed us to evaluate the efficacy of the ERT method in studying active faults and the structural setting of seismogenic areas. In the Timpa del Vento intermontane basin, high resolution ERT across the Caggiano Fault scarps, with different arrays, electrode spacing (from 1 to 10 m) and penetration depth (from about 5 to 40 m) was carried out. The obtained resistivity models allowed us to locate the fault planes along the hillslope and to gather information at depth, as later con-firmed by paleoseismological trenches excavated across the fault trace. In the Ufita River Valley a 3560-m-long ERT was carried out across the basin, joining 11 roll-along multi-channel acquisition system with an electrode spacing of 20mand reaching an investigation depth of about 170 m. The ERT allowed us to reconstruct the geometry and thickness of the Quaternary deposits filling the Ufita Valley. Our reconstruction of the depositional setting is in agreement with an interpretative geological section based on borehole data

    Electrical resistivity tomography investigations in the ufita Valley (southern Italy).

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    Several Electrical Resistivity Tomography (ERT) surveys have been carried out to study the subsurface structural and sedimentary settings of the upper Ufita River valley, and to evaluate their efficiency to distinguish the geological boundary between shallow Quaternary sedimentary deposits and clayey bedrock characterized by moderate resistivity contrast. Five shallow ERTs were carried out across a morphological scarp running at the foot of the northeastern slope of the valley. This valley shoulder is characterized by a set of triangular facets, that some authors associated to the presence of a SW-dipping normal fault. The geological studies allow us to interpret the shallow ERTs results obtaining a resistivity range for each Quaternary sedimentary deposit. The tomographies showed the geometrical relationships of alluvial and slope deposits, having a maximum thickness of 30-40 m, and the morphology of the bedrock. The resistivity range obtained for each sedimentary body has been used for calibrating the tomographic results of one 3560m-long deep ERT carried out across the deeper part of the intramountain depression with an investigation depth of about 170 m. The deep resistivity result highlighted the complex alluvial setting, characterized by alternating fine grained lacustrine deposits and coarser gravelly fluvial sediments
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