Long-term moisture measurements in large-scale bioreactor cells using TDR and neutron probes.

This paper investigates the measurement of moisture content in municipal solid waste using two different indirect techniques: neutron scattering and time-domain reflectometry (TDR). Therefore, six laboratory-scale landfill bioreactors were instrumented with both neutron and TDR probes; in addition to that a gravimetric moisture balance was established for each cell. Different leachate recirculation modes were applied to perform different wetting conditions. In a first step, both probes were calibrated based on the water balance from three cells presenting homogeneous water distributions and sufficient temporal moisture variations. The calibration functions were then used for temporal and spatial moisture monitoring of all six cells. The results show that both methods are sensitive to moisture variations and provide interesting information on the complexity of vertical flows within the municipal solid waste. Nevertheless, it appears that neutron scattering offers better accuracy at the laboratory scale.

Improvement of electrical resistivity tomography for leachate injection monitoring.

Leachate recirculation is a key process in the scope of operating municipal waste landfills as bioreactors, which aims to increase the moisture content to optimize the biodegradation in landfills. Given that liquid flows exhibit a complex behaviour in very heterogeneous porous media, in situ monitoring methods are required. Surface time-lapse electrical resistivity tomography (ERT) is usually proposed. Using numerical modelling with typical 2D and 3D injection plume patterns and 2D and 3D inversion codes, we show that wrong changes of resistivity can be calculated at depth if standard parameters are used for time-lapse ERT inversion. Major artefacts typically exhibit significant increases of resistivity (more than +30%) which can be misinterpreted as gas migration within the waste. In order to eliminate these artefacts, we tested an advanced time-lapse ERT procedure that includes (i) two advanced inversion tools and (ii) two alternative array geometries. The first advanced tool uses invariant regions in the model. The second advanced tool uses an inversion with a "minimum length" constraint. The alternative arrays focus on (i) a pole-dipole array (2D case), and (ii) a star array (3D case). The results show that these two advanced inversion tools and the two alternative arrays remove almost completely the artefacts within +/-5% both for 2D and 3D situations. As a field application, time-lapse ERT is applied using the star array during a 3D leachate injection in a non-hazardous municipal waste landfill. To evaluate the robustness of the two advanced tools, a synthetic model including both true decrease and increase of resistivity is built. The advanced time-lapse ERT procedure eliminates unwanted artefacts, while keeping a satisfactory image of true resistivity variations. This study demonstrates that significant and robust improvements can be obtained for time-lapse ERT monitoring of leachate recirculation in waste landfills.

Intestinal infarction: report of 98 cases.

The Authors conducted a retrospective study on 98 patients with intestinal infarction observed from 1987 to 1999 in the Emergency Care Unit of the Loreto Hospital, Naples. In our hospital there are over 20,000 admissions, 3,900 of whom in the Emergency Care Unit. Intestinal infarction accounts for 0.049% of all admissions and 0.45% of emergency surgery admissions. About 500 laparotomies are performed annually, 1% of which for intestinal infarction. All patients in this series were operated on within 10 hours of admission. The following procedures were performed: 31 jejuno-ileal resections; 26 right hemicolectomies associated with small intestine resection; 5 upper mesenteric artery embolectomies plus wide gut resections (3 also underwent second-look operations within 36 hours of the initial surgery with further gut resection); 1 Hartmann's and 5 Volkmann's operations (all of these patients had colonic gangrene); 30 (30.5%) underwent exploratory laparotomy due to massive infarction. The prognosis of intestinal infarction is still ominous. Our mortality rate is 68%. Both clinical and laboratory data are non-specific and delayed diagnosis is the main cause of this mortality rate. Abdominal CT is an accurate and sensitive diagnostic tool. TPN enables us to achieve good nutritional support even for wider resections.

[Leiomyosarcoma of the small intestine and the colorectum. A case contribution]. / Il leiomiosarcoma del tenue e del colon-retto. Contributo casistico.

Smooth muscle tumors of the alimentary tract are uncommon. A retrospective study was made of 7 patients treated for leiomyosarcoma of the small and large bowel to identify prognostic factors that influence results. The symptoms associated with these tumors varied according to the anatomic sites of the lesions and the position of the growth in relation to the intestinal lumen but the most common presenting clinical signs are bleeding or obstruction. The differential diagnosis between benign and malignant smooth muscle tumors is sometimes quite difficult. Clinical behavior of the myosarcomas of the gastrointestinal tract can be predicted to a large extent by the site of the tumor, the presence or absence of invasion of adjacent vital organs, and the histopathologic grade of malignancy. Although the mitotic activity of a gastrointestinal stromal tumor remains the most critical prognostic factor, tumors have been seen to recur locally and to metastasize even with rare or absent mitotic figures. Further studies are needed to pinpoint the factors that may be correlated to the prognosis.

[Colorectal obstruction caused by cancer]. / L'occlusione retto-colica da cancro.

The authors report their experience, matured in 10 years, in the management of cancer of the rectum and large bowel complicated by obstruction; 425 patients out of 493 total cases of colorectal cancer presented an intestinal obstruction and underwent emergency surgery. In 386 cases it was possible to perform resection (91%). The surgical treatment of the patients with right colon obstruction usually consisted of a right hemicolectomy. The surgical treatment of left colon obstruction is still controversial; in the experience of the authors it was accomplished by Hartmann operation mainly until 1985; in recent years the authors have introduced a procedure of intraoperative anterograde irrigation of the colon and they have performed resection-anastomosis in a single stage successfully but only in selected patients. In 4 out of twelve cases of cancer of the splenic flexure a subtotal colectomy was performed with one stage ileo-sigmoid anastomosis crowned with success. The authors examine the operative and postoperative mortality of the patients with colorectal cancer and point out that 5 years survival is worse in patients with colorectal obstruction compared to elective operations (24% versus 41%).

[Verneuil's suppurative hidradenitis. A case report]. / L'idrosadenite suppurativa di Verneuil. Contributo clinico.

The Authors reports a case of Verneuil's disease in a perineal location. They focus on etiopathogenetic aspects and problems of differential diagnosis, before reviewing the various therapeutic options. Surgery is the only effective therapy and takes the form of an extensive excision of the cutaneous zone affected with 2nd intention recovery, or a dermoepidermal auto-graft. A long follow-up is important to monitor the possible recurrence of lesions generally due to the incomplete removal of the area affected by the process.

[Peritoneal splenosis. Report of a case and pathogenetic considerations]. / Splenosi peritoneale. Segnalazione di un caso e considerazioni patogenetiche.

A clinical case of splenosis recently observed in a young man subjected at the age of 8 to splenectomy for rupture of the spleen and operated at 19 for intestinal occlusion is reported. The pathogenetic aspects of the condition, characterised by the presence of nodules of splenic tissue in the abdominal cavity, are examined through a review of the literature.

[Hormonal regulation of uterine contraction]. / Regolazione ormonale della contrattilità uterina.

A personal method has been used to study spontaneous kinetic activity of the uterus in 50 women during puerperium following miscarriage between the VIIIth and XIIth weeks. Modifications induced were evaluated in several sessions (510 recordings) and at various periods of time, following administration of: 50 mg of 17B oestradiol, 200 mg natural progesterone, 500 mg of natural progesterone, 250 mg of 17 hydroxyprogesterone caproate and 500 mg of 17 hydroxyprogesterone caproate. In the case of some of the patients, hysterotonometry was evaluated following intravenous oxytocin loading. The results pointed to an activation of the uterine pacemaker after oestrogenic loading, and a clear-cut progestinic block of contractile activity.

[Effect of estradiol on carbohydrate metabolism in the uterine musculature]. / Effetto dell'estradiolo sul metabolismo glicidico del muscolo uterino.

The Effect of 7.5 micrograms i.v. 17-beta-oestradiol on the sugar metabolism of the uterine musculature was studied in 180-200 g Wistar rats. The myometrial metabolic reaction consisted of increased glucose phosphorylation, enhanced utilisation of creatine phosphate, and increased production of adenosine triphosphate and creatine phosphate initially, followed by their consumption. The gradual fall in the lactate: pyruvate ratio showed that this stimulation of glycolysis was not occurring in the absence of oxygen.

[Bases of infusional therapy. Note. I. Fluid balance]. / Basi della terapia infusionale. Nota i: Bilancio dei liquidi

The complex hydroelectrolytic problem is examined by a study of the physiology and physiopathology of fluids, electrolytes and proteins. A number of interesting critical and clinical problems of use in the pre- and postoperative treatment of surgical patients and in cases where a change in the hydroelectric balance takes place, are involved. Therapy is facilitated if needs are calculated on the basis of the three basic principles: 1) daily physiological need; 2) replacement of physiological losses; 3) elimination of the existing deficiency.