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Tracheal disruption is a life-threatening rare complication of total thyroidectomy that it should be prevented. The own-patient risk factors, procedure of tracheal intubation and a meticulous surgical technique are three main keys to keep in mind. Both medical and surgical management of this injury depends on its size, location and patient’s symptoms although neither of them prevents late complications. An early diagnosis could improve with prognosis although it is mandatory to perform either respiratory functional or imaging study in order to assume its healing. When the tracheal laceration is diagnosed during the surgery, we should take care with a continuous monitoring of the patient’s vital signs. A good oxygenation will be succeeded in high volume and low pressure with endotracheal tube distal to the lesion. We advice placing a tube drain near the disruption to prevent emphysema and an early extubation to avoid an ischaemic damage of the mucosa. A postoperative suspicion of tracheal rupture could demand reintubation with the patient in full relaxation and an examination by CT-scan or fiberscope before deciding a simple supportive therapy. We present our therapeutic experience in a female patient who suffered from tracheal injury during total thyroidectomy and describe a review of literature.

Introduction: Presacral tumours are extremely rare entities as the asymptomatic retrorectal mass, although its clinical presentation includes infectious complications and signs of malignant degeneration. Magnetic resonance imaging is the most efficient imaging study for its diagnosis. The treatment of choice is complete surgical excision and traditional approaches are mainly through abdominal, posterior and perineal approach, depending on anatomical characteristics of the lesion. Laparoscopic excision of these retrorectal lesions has been reported in a few cases. Patients and methods: We report two cases of 38 and 24-year-old women who complained of anorectal symptoms and were diagnosed as retrorectal tumour by imaging studies. One of them was infected. Both cases were resected by means of laparoscopic techniques. There was no surgical complication and they were discharged on the 3rd and 4th postoperative day, respectively. Histopathologic findings revealed benign cystic teratoma in both cases. A follow-up after 36 months showed no recurrence. Our surgical endoscopic technique and a brief review of perioperative cares are presented and discussed. Discussion: Laparoscopic excision could be indicated in selected retrorectal tumours and a great surgeon’s resolve is always required. A meticulous dissection must be performed in order to identify and preserve vital structures. It’s only absolute contraindications seemed to be the suspicion of malignancy and operative inexperience. Conclusions: The complete laparoscopic removal of presacral lesions is a responsible surgical procedure which offers advantages from the sanitary and aesthetic point of view. This new endoscopic indication could be considered probably as a better technique than open approach in selected patients.

The hydrogen trapping characteristics of 13CrNiMo martensitic steel weld metals, with different austenite contents resulting from different post-weld heat treatments, have been analysed. Scanning electron microscopy and X-ray diffraction have been used to study stable austenite resulting from intercritical tempering of these soft martensitic stainless steels weld metals. Austenite contents up to 25 vol.% have been obtained. Hydrogen diffusion and permeation coefficients have been obtained from an analysis of the permeation rate of hydrogen through these materials. A decrease of the hydrogen apparent diffusion coefficient is observed when the tempering temperature is increased in the range 400 ° C ⩽T⩽670 ° C ; this decrease is attributed to changes in the martensitic matrix as well as to the increase of austenite content. The role of the austenite phase on trapping is discussed.

In previous works, extensive desulphurisation, including shape control and low hardness in segregation zones, were pointed out as effective ways for increasing resistance to hydrogen induced cracking (HIC) in steels exposed to wet H2S environment. In this study, the behaviour of eight plates was evaluated by immersing samples in H2S-saturated NACE solution. HIC susceptibility was assessed by an ultrasonic method and correlated with the elongated MnS inclusion distribution. The results allow us to remark that an extremely low sulphur level is not necessary to reach good HIC resistance, provided that no hard bands are present in the steel. Under this condition, a relationship to calculate the minimum average sulphide length which provides low HIC susceptibility was found.

The objective of this study was to investigate the effects of DL-malate on the in vitro fermentation of a 50 : 50 forage : concentrate diet using the rumen simulation technique (RUSITEC) and to compare these effects with those induced by the addition of propionate. The RUSITEC system consisted of eight vessels: three of them received daily 5.62 mmol of DL-malate, three vessels received daily 5.62 mmol of propionate and two vessels received no additives (control). After an adaptation period of 11 days the main fermentation parameters were determined for five consecutive days. There were no significant differences between treatments either in pH or in the daily production of NH3‐N. Compared to control diet, the addition of DL-malate resulted in an increase (p < 0.05) of hemicellulose disappearance and a trend (p < 0.10) towards a greater disappearance of dry matter, organic matter and neutral detergent fibre. Differences between DLmalate and propionate in diet degradation were not significant. DL-malate treatment resulted in an increase (p < 0.01) of daily propionate production, and a decrease (p < 0.05) in the amount of both methane (mmol/g DM fermented) and L-lactate (mg/day). Compared to propionate, DL-malate produced an increase (p < 0.05) of acetate production and tended to produce a lower amount of propionate (p < 0.10). In conclusion, these results seem to indicate that DL-malate enhanced the in vitro fermentation by increasing production of propionate and digestibility of hemicellulose. # 1999 Published by Elsevier Science B.V. All rights reserved.

The effects on the hydrogen embrittlement (HE) due to variation of the delta ferrite contents were investigated on austenitic stainless steel welds. The hydrogen distriburion in the microstructure was studied by means of the hydrogen microprint technique. The damage caused by the hydrogen was evaluated through bending and tensile tests. The ferrite-austenite interfaces act as hydrogen traps. Ferrite increases the susceptibility to hydrogen, the greater the quantity of ferrite, the more HE, which basically modifies the form in which the hydrogen damages the material: it causes the austenite to change from a normal fragile fracture to a ductile fracture, accompanying the ferrite fragile fracture.

Eleven sun-cured hays with a crude protein and neutral-detergent fibre contents ranging from 57 to 207 g kg −1 and 428 to 744 g kg −1 dry-matter (DM) respectively, were used to study the suitability of different in vitro and in situ methods to estimate the extent and rate of degradation in the rumen. The methods used to study degradation kinetics were: (1) DM disappearance when a sample of each hay was placed in nylon bags and incubated in the rumen for different lengths of time, (2) gas production (GAS) at different incubation times when hays were incubated in vitro with buffered rumen fluid, (3) DM disappearance at different incubation times in a cellulase solution (CEL), (4) sugars (SUGAR) release to the supernatant after incubation in the cellulase solution and (5) optical density of the supernatant at λ =280 nm (as indicator of phenolic compounds release) after solubility in the cellulase (PHEN). All kinetic data were fitted to first-order kinetic models. From the relationships between gas production and DM degradation in situ it was estimated that 0.295 ml (SE 0.0335) gas were produced per mg of DM degraded for incubation times beyond 24 h, although this ratio was significantly lower for short incubation times. There were significant ( P P P >0.05) correlated with those obtained by other methods. Methods in situ, GAS and CEL resulted in similar relative ranking of forages according to their degradation rate (significant Spearman rank correlation coefficients), although there were significant differences in the absolute values estimated. Those differences were larger as the legumes proportion of the hays was greater. In situ degradation characteristics can be estimated from in vitro gas production parameters, although prediction equations were different depending on the botanical composition of the hay.

9 pages, 5 tables., Twenty four Churra lambs from multiple births were assigned to a 3x2 factorial design, with three levels of milk intake (837-L, 1046-M and 1255-H kJ gross energy per kg metabolic body weight per day) and two sexes (males and females). The effects of these factors on growth rate during the milk-feeding period (0 to 30 days), weaning period (31 to 37 days) and post-weaning period (38 to 77 days) were studied. The live weight gain during the milk-feeding period was statistically different (P

Young's moduli of AISI 1005 and 1070 steels, in different metallurgical states, were measured before and after hydrogen charging by means of the classical resonant bar method. Different decreases in Young's modulus were found which could be correlated with the microstructural state of the steel. The maximum diminution of elastic modulus was observed for the martensitic structure of 1070 steel (−1.7%) and the minimum in 1005 steel in the normalized state (−0.4%). Moreover a linear relationship was established between the change of Young's modulus from the effect of hydrogen and the hydrogen embrittlement susceptibility of these steels.

Shot-peening surface treatments were performed on a low-carbon steel and a 304 stainless steel. The influence of residual stresses on hydrogen permeation and distribution was investigated. The results were correlated with the tensile properties measured in air after cathodic charging and in a NACE medium under slow load-rate straining. The role of shotpeening on the hydrogen embrittlement of the low-carbon steel is strongly dependent on the severity of the hydrogen environment and testing conditions. The detrimental effect of shotpeening on the hydrogen embrittlement of the stainless steel is related to phase transformations induced by cold work.

The effect of the microstructure on the hydrogen embrittlement susceptibility, hydrogen mobility and hydrogen distribution in a low carbon steel was studied by means of the electrochemical permeation method (electrochemical and gas charging), mechanical tests and hydrogen microprint technique. The hydrogen diffusivity attains a minimum value in a fresh martensite and diffusivity increases with increasing tempering temperature. The quantity of desorbed hydrogen is at a maximum for a fresh martensite and decreases with increasing tempering temperature. The trapping energy was estimated to be ∼ 46 kJ mol −1 . There is a direct relationship between hydrogen embrittlement susceptibility and the quantity of desorbed hydrogen as well as between the hydrogen segregation and crack location. The steady state flux is maximum for a normalized state. These facts can be explained in terms of hydrogen trapping process.

The distribution of carbon in the microstructure of the twinned martensite of Fe-23 Ni-0.4 C, has been studied by microautoradiography of radioactive carbon 14. A statistical analysis of the autoradiographs, observed in the scanning electron microscope for massive specimens or in the transmission electron microscope for thin foils, show that: (i) clustering of carbon in the twin boundaries of the martensite plates occurs rapidly by ageing at room temperature; (ii) two twinning systems may be active sites for carbon clustering in the same plate; (iii) carbon segregation seems more pronounced in twin boundaries than in martensite-martensite, martensite-austenite, or mid-rib interfaces; (iv) the precipitation of ∈-carbide by ageing at 100 and 150° C is confirmed.

The need to change the current paradigm from linear economy to circular economy makes the recovery of resources from waste effluents one of the current and future technological priorities. In this context, sewage sludge represents a great challenge and at the same time a great opportunity for the recovery of resources, both material, and energy. Within the framework of the H2020 SMART Plant project, BETA Tech. Centre is developing two technologies to maximise resource recovery from different types of sludge. Firstly, phosphorus-rich biofertilisers are being produced through advanced dynamic composting processes treating sludge from EBPR and SCENA processes. Secondly, cellulose-rich sludge is being treated through biodrying processes to produce biomass fuel with a calorific value similar to that of pine chips. &nbsp

The need to change the current paradigm from linear economy to circular economy makes the recovery of resources from waste effluents one of the current and future technological priorities. In this context, sewage sludge represents a great challenge and at the same time a great opportunity for the recovery of resources, both material, and energy. Within the framework of the H2020 SMART Plant project, BETA Tech. Centre is developing two technologies to maximise resource recovery from different types of sludge. Firstly, phosphorus-rich biofertilisers are being produced through advanced dynamic composting processes treating sludge from EBPR and SCENA processes. Secondly, cellulose-rich sludge is being treated through biodrying processes to produce biomass fuel with a calorific value similar to that of pine chips.