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The use of digital elevation models (DEMs) allows the automatic derivation of channel networks and the quantitative description of the geomorphic characteristics of basins. A common method of channel network extraction from DEM data is based on the specification of a threshold area (A{sub}t{end}) that is the minimum support area required to drain to a point for a channel to form. Usually, an arbitrary constantthreshold area value is chosen for channel network extraction. In this study the effects of threshold area selection, both on the morphometric and scaling properties (such as drainage density, total channellength, Horton laws and fractal dimension) of a channel network and the associated hydrological response function are analysed. The response is obtained following the geomorphological instantaneous unit hydrograph theory. Two different probabilistic models are used. They both relate the characteristic response function of the basin to its DEMdata derived networks: one is derived assuming a Strahler stream ordering system and the other is obtained by averaging a flow equation with respect to the network structure (described by the width function). Applications are shown for three mountainous basins in the ItalianAlps. A sensitivity analysis is performed to study the influence of the variability of morphometric properties, with respect to A{sub}t{end}, on the hydrological response obtained. It is shown that the model based on the width function is able to reduce the effects of this variability on the simulated response. [ABSTRACT FROM AUTHOR]

Organic phase change materials, e.g., paraffins, are attracting increasing attention in thermal energy storage (TES) and thermal management applications. However, they also manifest interesting optical properties such as thermotropism, as they can switch from optically opaque to transparent reversibly and promptly at the melting temperature. This work aims at exploiting this feature to produce flexible silicone-based blends with thermotropic properties for applications in glazed windows or thermal sensors. Blends are produced by adding paraffin (T m = 44 °C, up to 10 phr) to a silicone bicomponent mixture, and, for the first time, cetyltrimethylammonium bromide (CTAB) is also added to promote paraffin dispersion and avoid its exudation. CTAB is proven effective in preventing paraffin exudation both in the solid and in the liquid state when added in a fraction above 3 phr with respect to paraffin. Rheological results show that paraffin decreases the complex viscosity, but neither paraffin nor CTAB modifies the curing behavior of silicone, which indicates uniform processability across the investigated compositions. On the other hand, paraffin causes a decrease in the stress and strain at break at 60 °C, and this effect is amplified by CTAB, which acts as a defect and stress concentrator. Conversely, at room temperature, solid paraffin only slightly impairs the mechanical properties, while CTAB increases both the elastic modulus and tensile strength, as also highlighted with ANOVA. Finally, optical transmittance results suggest that the maximum transmittance difference below and above the melting temperature (65-70 percentage points) is reached for paraffin amounts of 3 to 5 phr and a CTAB amount of max. 0.15 phr.

In the surgical management of large incisional hernias, the main target is the closure of the abdominal wall defect on the midline without a dangerous increase in the intraabdominal pressure. In this setting, new intraperitoneal prosthesis and components separation techniques were proposed to solve this problem. Both solutions present some critical issues. A new surgical approach with a free lateral double layer prosthesis totally in polypropylene both sides (FLaPp ® ) is proposed to overcome this problem. This is a retrospective cohort analysis study with a prospectively collected database from two different Italian hospitals. Twenty-nine patients operated from April 2010 to December 2015 were treated using the new prosthesis. Four patients developed postoperative complications: one (3.4%) presented wound infection, two (6.9%) experienced seroma, and one had a hematoma (3.4%). No deaths were recorded. At a median follow-up of 28.5 months (IQR 22-36), no hernia relapse occurred. The application of FLaPp ® mesh is a safe and feasible option that can be employed to manage Rives repair in cases of abdominal wall defects with difficult closure of the posterior plan when the conventional prosthetic meshes could be unsuitable.

Late cutaneous fistulae, after a hernioplasty operation for a hernia in the abdominal wall, represent an unusual complication. They can appear a considerable time after a hernioplasty operation and feature the presence of a fistula between the prosthesis and the cutaneous wall. The Authors report the cases of five patients who developed late cutaneous fistulae after an operation for the repair of a hernia of the abdominal wall and the treatment established in the end to correct the existing complication. All five patients were subjected to a second operation to achieve recovery. In fact, conservative medical treatment, before the operation, using antibiotic-therapy for this purpose proved to be ineffective. Only one patient developed hernia recurrence after surgical treatment. Late cutaneous fistulae represent a complication that is difficult to deal with as their treatment has yet to be clearly identified.

Para-oesophageal hiatus hernia, a condition in which the fundus and part of the body of the stomach wrapped in a peritoneal sac herniate into the mediastinum, is a relatively uncommon entity. It tends to grow progressively and may become so large as to lead to symptoms of intrathoracic organ compression. In some exceptional cases, the entire stomach together with other abdominal viscera might herniate through the hiatus into the thorax. Paraesophageal hiatus hernias are characterised clinically by vague symptomatology, absent gastro-oesophageal reflux, and possible onset of gastric volvulus, generally without consequent incarceration of the portion of the herniated organ. Such an event is uncommon but dangerous and life-threatening. These cases often require resection of the incarcerated viscera, followed by hiatoplasty and Nissen fundoplication. The authors report on the case of a patient presenting with acute abdomen as a result of incarcerated and perforated para-oesophageal hiatus hernia.

Sarcomatoid carcinomas of the lung are uncommon neoplasms; the concurrent presence of malignant epithelial and sarcomatoid spindle cell components show a high malignancy. Lymph node metastases at presentation is an important prognostic factor, on the other way the most patients with sarcomatoid carcinoma of the lung usually presented at an advanced stage that needed a complementary therapy. The Authors report about one surgical case of pulmonary carcinosarcoma recently observed without lymph node metastases; the literature is reviewed and the histogenesis is discussed.

A case of leiomyoma of the small bowel which growth in the mesentery is reported. After review of the late literature, the Authors prove that this tumor is rare. The clinical examination and the simptoms associated with this neoplasm are aspecific for many months, so that X-ray as well as other complementary examinations are often necessary for the diagnosis.