2,160 research outputs found

    Aerosol optical properties at Lampedusa (Central Mediterranean). 1. Influence of transport and identification of different aerosol types

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    Aerosol optical depth and Ångström exponent were obtained from multi filter rotating shadowband radiometer (MFRSR) observations carried out at the island of Lampedusa, in the Central Mediterranean, in the period July 2001–September 2003. The average aerosol optical depth at 495.7 nm, τ, is 0.24±0.14; the average Ångström exponent, α, is 0.86±0.63. The observed values of τ range from 0.03 to 1.13, and the values of α vary from −0.32 to 2.05, indicating a large variability in aerosol content and size. In cloud-free conditions, 36% of the airmasses come from Africa, 25% from Central-Eastern Europe, and 19% from Western France, Spain and the North Atlantic. In summer, 42% of the airmasses is of African origin. In almost all cases African aerosols display high values of τ and low values of α, typical of Saharan dust (average values of τ and α are 0.36 and 0.42, respectively). Particles originating from Central-Eastern Europe show relatively large average values of τ and α (0.23 and 1.5, respectively), while particles from Western France, Spain and the North Atlantic show the lowest average values of τ (0.15), and relatively small values of α (0.92). Intermediate values of α are often connected with relatively fast changes of the airmass originating sector, suggesting the contemporary presence of different types of particles in the air column. Clean marine conditions are rare at Lampedusa, and are generally associated with subsidence of the airmasses reaching the island. Average values of τ and α for clean marine conditions are 0.11 and 0.86, respectively. The largest values of α (about 2) were observed in August 2003, when large scale forest fires in Southern Europe produced consistent amounts of fine combustion particles, that were transported to the Central Mediterranean by a persistent high pressure system over Central Europe. Smoke particles in some cases mix with desert dust, producing intermediate values of α. The seasonal distribution of the meteorological patterns over the Mediterranean, the efficiency of the aerosol production mechanisms, and the variability of the particles' residence time produce a distinct seasonal cycle of aerosol optical depths and Ångström exponent values. Particles originating from all sectors show a summer maximum in aerosol optical depth. The summer increase in optical depth for European aerosols is linked with an increment in the values of α, that indicates an enhancement in the number of fine particles. The summer maximum of τ for African particles is associated with a weak reduction in the Ångström exponent, suggesting an increase in the total number of particles and a relatively more intense transport of large particles. The observations were classified according to the aerosol optical properties, and two main classes have been identified: desert dust and biomass burning/urban-industrial aerosols. Values of τ and α averaged over the whole observing period are 0.37 and 0.15 for desert dust, and 0.27 and 1.77 for urban-industrial/biomass burning aerosols

    Ileocecal duplication cysts: Is the loss of the valve always necessary?

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    Ileocecal (IC) duplication cysts are enteric duplications located at the IC junction, not clearly identified in all the published series. The reported treatment is IC resection and ileocolic anastomosis. It is well known that the loss of the IC valve has several adverse effects. This study is aimed at demonstrating that cyst removal together with the common ileal wall and following enterorrhapy is possible, safe, and effective in preserving the IC region. Methods Medical records of 3 patients who underwent surgery for IC duplication between 2003 and 2013 were retrospectively reviewed evaluating follow-up results. Results All patients had an antenatal diagnosis of intrabdominal cystic mass. In two cases associated malformations were reported. The lesions presented at newborn age with intermittent small bowel obstruction and required removal. No patients underwent IC resection. The diagnosis of duplication cyst was confirmed by histo-pathologic examination. The postoperative course was uneventful, even in the long-term follow-up

    Evolving management of adolescent varicocele

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    OBJECTIVE: To review the evolution in indications for treatment and treatment modalities for adolescent varicocele at our centre, and evaluate the impact of varicocelectomy on final outcome. PATIENTS AND METHODS: Between 1995 and 2006, we treated 242 left varicoceles. Preoperative assessment included clinical evaluation, measurement of testicular volumes, and colour-Doppler ultrasound (CDUS). A subinguinal varicocelectomy was performed in 124 patients (group A), and a laparoscopic non-artery-sparing Palomo procedure in the remaining 118 (group B). In group B patients, CDUS was also used to investigate the functional anatomy of varicocele, and all the veins found to be refluxing were divided during surgery. The two groups were compared with regard to indications for surgery and outcome. RESULTS: Over time the proportion of patients operated on because of testicular growth retardation increased. Persistence/recurrence rate was comparable between the two groups. In 13% of group B patients, the deferential vein was found to be refluxing on preoperative CDUS and was divided at surgery. Hydrocele rate was higher in group A, unless the vaginalis was excised and everted during varicocelectomy. About 75% of patients with preoperative left testicular growth failure experienced postoperative catch-up growth, irrespective of treatment. CONCLUSION: Indications for treatment are still evolving. Varicocele can successfully be treated in the majority of cases by either a laparoscopic or subinguinal approach. Both techniques require care, and CDUS can aid in the decision making. Most patients with preoperative testicular growth failure experience postoperative catch-up growth

    A simple technique of oblique anastomosis can prevent stricture formation in primary repair of esophageal atresia

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    Background: Anastomotic stricture is an important problem after esophageal atresia (EA) repair. This study evaluates a technique of oblique esophageal anastomosis without use of a flap in order to prevent stricture formation. Methods: Medical records of 16 patients (14 with EA type III and 2 with EA type IV Ladd-Gross classification) who underwent primary repair of EA at birth without anastomotic tension were reviewed, evaluating long-term follow-up results. All patients were studied with esophageal contrast study, pH-multichannel intraluminal impedance, and endoscopy. The incidence of complications and their management were analysed. Results: Contrast esophagogram and esophagoscopy always showed regular patency of the suture line. Conclusions: Our technique of oblique anastomosis is simple, safe, and effective in preventing stricture formation even in the long-term follow-up

    Laparoscopic Surgery of Deferential Reflux in Pediatric and Adolescent Varicocele

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    BACKGROUND: This study aimed to assess whether deferential reflux in pediatric and adolescent varicocele can be successfully treated laparoscopically. MATERIALS AND METHODS: Since 2001 at our institution, 148 boys were evaluated for a left varicocele. Preoperatively,all the patients underwent ultrasound scan assessment of testicular volume and color-Doppler US (CDUS)to rule out reflux into the internal spermatic vein (ISV), deferential vein, or cremasteric vein. Boys with ISV reflux were treated by laparoscopic transperitoneal Palomo; boys with isolated deferential reflux or associated to ISV reflux were laparoscopically managed adding to the former procedure, coagulation or clipping of refluxing deferential veins. RESULTS: Reflux in both the ISV and the deferential vein was observed in 21 (14.1%) out 148 boys with varicocele.Only one case (0.6%) of varicocele was caused by an isolated deferential reflux. No reflux in the cremasteric vein was observed. After a median follow up period of 2 years (range, 6 months-5 years), none of our patients with deferential reflux experienced varicocele recurrence either clinically or according to CDUS scanning.No testicular atrophy was observed. CONCLUSION: Our diagnostic approach is a rigorous standard for identifying all the venous systems concurring with the varicocele. Our proposed technique with laparoscopic interruption or coagulation of deferential veins when proved by CDUS to be refluxing may allow successful treatment for most varicoceles. This method allows reduction in recurrence of varicocele due to a missed deferential reflux

    A long-term time series of global and diffuse photosynthetically active radiation in the Mediterranean: interannual variability and cloud effects

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    Abstract. Measurements of global and diffuse photosynthetically active radiation (PAR) have been carried out on the island of Lampedusa, in the central Mediterranean Sea, since 2002. PAR is derived from observations made with multi-filter rotating shadowband radiometers (MFRSRs) by comparison with a freshly calibrated PAR sensor and by relying on the on-site Langley plots. In this way, a long-term calibrated record covering the period 2002–2016 is obtained and is presented in this work. The monthly mean global PAR peaks in June, with about 160 W m−2, while the diffuse PAR reaches 60 W m−2 in spring or summer. The global PAR displays a clear annual cycle with a semi amplitude of about 52 W m−2. The diffuse PAR annual cycle has a semi amplitude of about 12 W m−2. A simple method to retrieve the cloud-free PAR global and diffuse irradiances in days characterized by partly cloudy conditions has been implemented and applied to the dataset. This method allows retrieval of the cloud-free evolution of PAR and calculation of the cloud radiative effect, CRE, for downwelling PAR. The cloud-free monthly mean global PAR reaches 175 W m−2 in summer, while the diffuse PAR peaks at about 40 W m−2. The cloud radiative effect, CRE, on global and diffuse PAR is calculated as the difference between all-sky and cloud-free measurements. The annual average CRE is about −14.7 W m−2 for the global PAR and +8.1 W m−2 for the diffuse PAR. The smallest CRE is observed in July, due to the high cloud-free condition frequency. Maxima (negative for the global, and positive for the diffuse component) occur in March–April and in October, due to the combination of elevated PAR irradiances and high occurrence of cloudy conditions. Summer clouds appear to be characterized by a low frequency of occurrence, low altitude, and low optical thickness, possibly linked to the peculiar marine boundary layer structure. These properties also contribute to produce small radiative effects on PAR in summer. The cloud radiative effect has been deseasonalized to remove the influence of annual irradiance variations. The monthly mean normalized CRE for global PAR can be well represented by a multi-linear regression with respect to monthly cloud fraction, cloud top pressure, and cloud optical thickness, as determined from satellite MODIS observations. The behaviour of the normalized CRE for diffuse PAR can not be satisfactorily described by a simple multi-linear model with respect to the cloud properties, due to its non-linear dependency, in particular on the cloud optical depth. The analysis suggests that about 77 % of the global PAR interannual variability may be ascribed to cloud variability in winter

    Efficacy of periportal infiltration and intraperitoneal instillation of ropivacaine after laparoscopic surgery in children

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    Postoperative pain is less intense after laparoscopic than after open surgery. However, minimally invasive surgery is not a a pain-free procedure. Many trials have been done in adults using intraperitoneal and/or incisional local anesthetic, but similar studies have not yet been reported in the literature in children. Aim: The aim of this study was to evaluate the analgesic effect of periportal infiltration and intraperitoneal instillation of ropivacaine in children undergoing laparoscopic surgery. Materials and Methods: Thirty patients who underwent laparoscopic surgery were randomly allocated to one of three groups. Group A (n 10) received local infiltration of port sites with 10 mL of ropivacaine. Group B (n 10) received both an infiltration of port sites with 10 mL of ropivacaine and an intraperitoneal instillation of 10 mL of ropivacaine. Group C did not receive any analgesic treatment. The local anesthetic was always administered at the end of surgery. The degree of postoperative abdominal parietal pain, abdominal visceral pain, and shoulder pain was assessed by using a Wong-Baker pain scale and a Visual Analog Scale (VAS) at 3, 6 12, and 24 hours postoperatively. The following parameters were also evaluated: rescue analgesic treatment, length of hospital stay, and time of return to normal activities. Results: Three hours after operation, patients had low pain scores. Six and 12 hours postoperatively, the abdominal parietal pain was significantly higher (P 0.0005) in group C than in the other two groups, both treated with an infiltration at the trocar sites; mean intensity of abdominal visceral pain was significantly lower (P 0.0005) in group B than in groups A and C; the overall incidence of shoulder pain was significantly lower (P 0.0005) in group B patients than in patients of groups A and C. At 20 hours postoperatively, pain scores were significantly reduced of intensity in all groups. Rescue analgesic treatment was significantly higher in group C, if compared to groups A and B 12 hours after the operation. No statistically significant difference was found in length of hospital stay, but children who received analgesic treatment had a more rapid return to normal activities than untreated patients (P 0.0005). Conclusions: Our study demonstrates that the combination of local infiltration and intraperitoneal instillation of ropivacaine is more effective for pain relief in children after laparoscopic surgery than the administration of ropivacaine only at the trocar sites

    Study of coupling loss on bi-columnar BSCCO/Ag tapes by a.c. susceptibility measurements

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    Coupling losses were studied in composite tapes containing superconducting material in the form of two separate stacks of densely packed filaments embedded in a metallic matrix of Ag or Ag alloy. This kind of sample geometry is quite favorable for studying the coupling currents and in particular the role of superconducting bridges between filaments. By using a.c. susceptibility technique, the electromagnetic losses as function of a.c. magnetic field amplitude and frequency were measured at the temperature T = 77 K for two tapes with different matrix composition. The length of samples was varied by subsequent cutting in order to investigate its influence on the dynamics of magnetic flux penetration. The geometrical factor χ0\chi_0 which takes into account the demagnetizing effects was established from a.c. susceptibility data at low amplitudes. Losses vs frequency dependencies have been found to agree nicely with the theoretical model developed for round multifilamentary wires. Applying this model, the effective resistivity of the matrix was determined for each tape, by using only measured quantities. For the tape with pure silver matrix its value was found to be larger than what predicted by the theory for given metal resistivity and filamentary architecture. On the contrary, in the sample with a Ag/Mg alloy matrix, an effective resistivity much lower than expected was determined. We explain these discrepancies by taking into account the properties of the electrical contact of the interface between the superconducting filaments and the normal matrix. In the case of soft matrix of pure Ag, this is of poor quality, while the properties of alloy matrix seem to provoke an extensive creation of intergrowths which can be actually observed in this kind of samples.Comment: 20 pages 11 figure, submitted to Superconductor Science and Technolog

    Advanced management protocol of transanal irrigation in order to improve the outcome of pediatric patients with fecal incontinence

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    Background: Transanal irrigation (TAI) is employed for children with fecal incontinence, but it can present several problems which require a study of their outcomes among different patholo-gies and without a tailored work up. The aim of our study was to evaluate the effectiveness of an advanced protocol in order to tailor TAI, prevent complications, and evaluate outcomes. Methods: We included 70 patients (14 anorectal malformation, 12 Hirschsprung’s disease, 24 neurological impairment, 20 functional incontinence) submitted to a comprehensive protocol with Peristeen®: fecal score, volumetric enema, rectal ultrasound, anorectal 3D manometry, and diary for testing and parameter adjustment. Results: Among the patients, 62.9% needed adaptations to the parameters, mainly volume of irrigated water and number of puffs of balloon. These adaptations were positively correlated with pre-treatment manometric and enema data. In each group, the improvement of score was statistically significant in all cases (p 0.000); the main factor influencing the efficacy was the rate of sphincter anomalies. The ARM group had slower improvement than other groups, whereas functional patients had the best response. Conclusions: Our results showed that TAI should not be standardized for all patients, because each one has different peculiarities; evaluation of patients before TAI with rectal ultrasound, enema, and manometry allowed us to tailor the treatment, highlighting different outcomes among various pathologies, thus improving the efficacy
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