129 research outputs found

    Discharge estimation combining flow routing and occasional measurements of velocity

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    A new procedure is proposed for estimating river discharge hydrographs during flood events, using only water level data at a single gauged site, as well as 1-D shallow water modelling and occasional maximum surface flow velocity measurements. One-dimensional diffusive hydraulic model is used for routing the recorded stage hydrograph in the channel reach considering zero-diffusion downstream boundary condition. Based on synthetic tests concerning a broad prismatic channel, the “suitable” reach length is chosen in order to minimize the effect of the approximated downstream boundary condition on the estimation of the upstream discharge hydrograph. The Manning’s roughness coefficient is calibrated by using occasional instantaneous surface velocity measurements during the rising limb of flood that are used to estimate instantaneous discharges by adopting, in the flow area, a two-dimensional velocity distribution model. Several historical events recorded in three gauged sites along the upper Tiber River, wherein reliable rating curves are available, have been used for the validation. The outcomes of the analysis can be summarized as follows: (1) the criterion adopted for selecting the “suitable” channel length based on synthetic test studies has proved to be reliable for field applications to three gauged sites. Indeed, for each event a downstream reach length not more than 500m is found to be sufficient, for a good performances of the hydraulic model, thereby enabling the drastic reduction of river cross-sections data; (2) the procedure for Manning’s roughness coefficient calibration allowed for high performance in discharge estimation just considering the observed water levels and occasional measurements of maximum surface flow velocity during the Correspondence to: G. Corato ([email protected]) rising limb of flood. Indeed, errors in the peak discharge magnitude, for the optimal calibration, were found not exceeding 5% for all events observed in the three investigated gauged sections, while the Nash-Sutcliffe efficiency was, on average, greater than 0.95. Therefore, the proposed procedure well lend itself to be applied for: (1) the extrapolation of rating curve over the field of velocity measurements (2) discharge estimations in different cross sections during the same flood event using occasional surface flow velocity measures carried out, for instance, by hand-held radar sensors

    Diagnostic approach and epidemiology of Microbial Keratitis: findings from an Italian Tertiary Care center

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    Rapid identification of causative microorganisms of microbial keratitis (MK) and knowledge of the most common local pathogens are prerequisites for rational antimicrobial therapy. We retrospectively reviewed the characteristics of MK diagnosed at the IRCCS Arcispedale Santa Maria Nuova of Reggio Emilia (Italy) in a 5-years period, where the Ophthalmologist Unit is a reference center for corneal infections. During the study period, 183 MK were evaluated through corneal scrapings cultures. The positivity rate was 54,1%. A total of 107 microorganisms have been isolated: Acanthamoeba species was the etiologic agent in 19 cases. Pseudomonas aeruginosa and Staphylococcus aureus were more frequently isolated in bacterial keratitis, while Fusarium spp., Candida albicans, and Alternaria alternata were predominant among the fungal isolates. Strict cooperation between ophthalmologists and clinical microbiologists is advisable to allow the best diagnostic approach for MK

    One step minilaparotomy-assisted transmesenteric portal vein recanalization combined with transjugular intrahepatic portosystemic shunt placement: A novel surgical proposal in pediatrics

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    Transjugular intrahepatic portosystemic shunt (TIPS) placement is a standard procedure for the treatment of portal hypertension complications. When this conventional approach is not feasible, alternative procedures for systemic diversion of portal blood have been proposed. A one-step interventional approach, combining minilaparotomy-assisted transmesenteric (MAT) antegrade portal recanalization and TIPS, is described in an adolescent with recurrent esophageal varice bleeding and portal cavernoma (PC). A 16-year-old girl was admitted to our Unit because of repeated bleeding episodes over a short period of time due to esophageal varices in the context of a PC. A portal vein recanalization through an ileocolic vein isolation with the MAT approach followed by TIPS during the same session was performed. In the case of failed portal recanalization, this approach, would also be useful for varice endovascular embolization. Postoperative recovery was uneventful. Treatment consisting of propanolol, enoxaparin and a proton pump inhibitor was prescribed after the procedure. One month post-op, contrast enhanced computed tomography confirmed the patency of the portal and intrahepatic stent grafts. No residual peritoneal fluid was detected nor opacification of the large varices. Endoscopy showed good improvement of the varices. Doppler ultrasound confirmed the accelerated flow in the portal stent and hepatopetal flow inside the intrahepatic portal branches. Three months post-op, TIPS maintained its hourglass shape despite a slight expansion. Portal hypertension and life threatening conditions related to PC would benefit from one-step portal recanalization. MAT-TIPS is feasible and safe for the treatment of PC even in children. This minimally invasive procedure avoids or delays surgical treatment or re-transplantation when necessary in pediatric patients

    Integrazione di metodologie dirette ed indirette per la stima degli idrogrammi di piena in alvei naturali

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    Le metodologie attualmente disponibili per la misura di pieno campo delle portate possono essere classificate in base al tipo di sensore utilizzato ed al numero delle stazioni idrometriche. Per ognuna delle possibili tipologie vengono presentate le tecniche di analisi piĂč recenti e delineati possibili sviluppi futuri. Viene quindi introdotta una nuova metodologia, basata sull’integrazione di misure dirette ed indirette. Nell’approccio proposto la portata viene calcolata come valore al contorno di monte di un modello di propagazione 1D a cui vengono assegnati i tiranti di monte quale condizione misurata. Il modello viene calibrato attraverso sporadiche misure istantanee di velocitĂ , consentendo di pervenire ad una registrazione continua delle portate mediante l’ausilio delle sole osservazioni dei tiranti in una sola stazione di misura. L’approccio Ăš validato attraverso serie storiche di tiranti e di portate misurate in una stazione idrometrica del Fiume Tevere

    Effect of Cromoglycate on Gas Changes, During Bronchial Challenge by UNCDW in Children with Asthma

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    Eighteen asthmatic children were challenged with ultrasonically nebulized cold distilled water (UNCDW). Blood gas composition was monitored transcutaneously (tcpO2 and tcpCO2) during and after the challenge. Assuming as basal the response to this UNCDW test, nine children (Group A) were then chosen at random to inhale cromoglycate by aerosol delivery for 8 days. Nine children (Group B), acting as a control, inhaled saline for 8 days. At the end of this therapy, each child repeated the UNCDW test. Statistical analysis with t-test for paired data was used to compare the results of each child to both tests. Mean basal tcpO2 and tcpCO2 were all within the expected normal range. In all children, both mean tcpO2 and tcpCO2 were reduced during and after UNCDW inhalation. Mean tcpCO2 values during the challenge were significantly (p < 0.001) lower than the corresponding steady state 2 rain after the UNCDW challenge, with a mean drop of −7% (2.1 S.D.). Mean tcpO2 values remained significantly decreased (p < 0.001) from the fifth mitt of the UNCDW challenge to the end of the observation period, with a mean drop of −20% (15.5 S.D.). After treatment with cromoglycate (Group A), the mean tcpCO2 values during UNCDW did not change significantly from those ofsteady state conditions: −0.8% (0.5 S.D.); whereas mean tcpO2 values decreased by −4% (4.9 S.D.). The control children treated with saline (Group B) showed mean tcpCO2 and tcpO2 values which were significantly different (p < 0.001) from those of the steady state conditions: mean drop of tcpCO2, −6% (4.2 S.D.); mean drop of tcpO2, −20% (4.7 S.D.). In conclusion, it emerges that: UNCDW induces nonspecific broncho-constriction in asthmatic children with a typical drop of tcpCO2 and tcpO2; the treatment with cromoglycate normalizes the time course of tcpCO2 (hyper-reactivity) and reduces dramatically the drop of tcpO2 time course (hyper-responsivity) during and after the UNCDW test

    Minimally invasive procedure for removal of infected ventriculoatrial shunts

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    Background: Ventriculoatrial shunts were one of the most common treatments of hydrocephalus in pediatric and adult patients up to about 40 years ago. Thereafter, due to the widespread recognition of the severe cardiac and renal complications associated with ventriculoatrial shunts, they are almost exclusively implanted when other techniques fail. However, late infection or atrial thrombi of previously implanted shunts require removal of the atrial catheter several decades after implantation. Techniques derived from management of central venous access catheters can avoid cardiothoracic surgery in such instances. Methods: We retrospectively investigated all the patients requiring removal of a VA shunt for complications treated in the last 5 years in our institution. Results: We identified two patients that were implanted 28 and 40 years earlier. Both developed endocarditis with a large atrial thrombus and were successfully treated endovascularly. The successful percutaneous removal was achieved by applying, for the first time in this setting, the endoluminal dilation technique as proposed by Hong. After ventriculoatrial shunt removal and its substitution with an external drainage, both patients where successfully weaned from the need for a shunt and their infection resolved. Conclusion: Patients carrying a ventriculoatrial shunt are now rarely seen and awareness of long-term ventriculoatrial shunt complications is decreasing. However, these complications must be recognized and treated by shunt removal. Endovascular techniques are appropriate even in the presence of overt endocarditis, atrial thrombi, and tight adherence to the endocardial wall. Moreover, weaning from shunt dependence is possible even decades after shunting

    Clinical and Epidemiological Study on Tubercular Uveitis in a Tertiary Eye Care Centre in Italy

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    PURPOSE: To describe frequency, clinical characteristics, and visual prognosis of tubercular uveitis (TBU) in a nonendemic country. METHODS: We retrospectively reviewed 3743 charts of patients with endogenous uveitis visited from 2008 to 2018 at a tertiary referral centre in Rome, Italy. We included immunocompetent patients with diagnosis of TBU. Patients were divided in two groups: patients with history of uveitis without a previous diagnosis of TBU (group A) and patients at their first episode of TB uveitis (group B). RESULTS: TBU was diagnosed in 28 (0.75%) out of 3743 patients. Twelve (42.9%) patients came from tuberculosis endemic areas. All patients received specific antitubercular treatment (ATT) and were evaluated for a mean follow-up of 3.2 ± 2.9 years. Group A showed a greater number of ocular complications when compared with group B. ATT was effective in reducing the frequency of recurrences of uveitis in patients of group B. CONCLUSION: Intraocular inflammation can be the first manifestation of tuberculosis. Our data highlight that early diagnosis and specific treatment of TBU may allow to decrease recurrences and to improve visual outcomes
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