A Review on Metallurgical Issues in the Production and Welding Processes of Clad Steels.

Carbon and low-alloy steel plates clad with stainless steel or other metals are a good choice to meet the demand for cost-effective materials to be used in many corrosive environments. Numerous technical solutions are developed for the production of clad steel plates, as well as for their joining by fusion welding. For thick plates, a careful strategy is required in carrying out the multiple passes and in choosing the most suitable filler metals, having to take into account the composition of the base metal and the cladding layer. The specificity of the different processes and materials involved requires an adequate approach in the study of the metallurgical characteristics of clad steel, thus arousing the interest of researchers. Focusing mainly on ferritic steel plates clad with austenitic steel, this article aims to review the scientific literature of recent years which deals with both the production and the fusion welding processes. The metallurgical issues concerning the interfaces and the effects of microstructural characteristics on mechanical behaviour and corrosion resistance will be addressed; in particular, the effects on the fusion and thermally affected zones that form during the fusion welding and weld overlay processes will be analysed and discussed.

The Overweight Paradox: Impact of Body Mass Index on Patients Undergoing VATS Lobectomy or Segmentectomy.

The aim of this study was to assess the impact of BMI on perioperative outcomes in patients undergoing VATS lobectomy or segmentectomy. Data from 5088 patients undergoing VATS lobectomy or segmentectomy, included in the VATS Group Italian Registry, were collected. BMI (kg/m2) was categorized according to the WHO classes: underweight, normal, overweight, obese. The effects of BMI on outcomes (complications, 30-days mortality, DFS and OS) were evaluated with a linear regression model, and with a logistic regression model for binary endpoints. In overweight and obese patients, operative time increased with BMI value. Operating room time increased by 5.54 minutes (S.E. = 1.57) in overweight patients, and 33.12 minutes (S.E. = 10.26) in obese patients (P < 0.001). Compared to the other BMI classes, overweight patients were at the lowest risk of pulmonary, acute cardiac, surgical, major, and overall postoperative complications. In the overweight range, a BMI increase from 25 to 29.9 did not significantly affect the length of stay, nor the risk of any complications, except for renal complications (OR: 1.55; 95% CI: 1.07-2.24; P = 0.03), and it reduced the risk of prolonged air leak (OR: 0.8; 95% CI: 0.71-0.90; P < 0.001). 30-days mortality is higher in the underweight group compared to the others. We did not find any significant difference in DFS and OS. According to our results, obesity increases operating room time for VATS major lung resection. Overweight patients are at the lowest risk of pulmonary, acute cardiac, surgical, major, and overall postoperative complications following VATS resections. The risk of most postoperative complications progressively increases as the BMI deviates from the point at the lowest risk, towards both extremes of BMI values. Thirty days mortality is higher in the underweight group, with no differences in DFS and OS.

Chemical Composition, Fatty Acid and Mineral Content of Food-Grade White, Red and Black Sorghum Varieties Grown in the Mediterranean Environment.

Grain sorghum (Sorghum bicolor) is a gluten-free cereal grown around the world and is a food staple in semi-arid and subtropical regions. Sorghum is a diverse crop with a range of pericarp colour including white, various shades of red, and black, all of which show health-promoting properties as they are rich sources of antioxidants such as polyphenols, carotenoids, as well as micro- and macro-nutrients. This work examined the grain composition of three sorghum varieties possessing a range of pericarp colours (white, red, and black) grown in the Mediterranean region. To determine the nutritional quality independent of the contributions of phenolics, mineral and fatty acid content and composition were measured. Minor differences in both protein and carbohydrate were observed among varieties, and a higher fibre content was found in both the red and black varieties. A higher amount of total saturated fats was found in the white variety, while the black variety had a lower amount of total unsaturated and polyunsaturated fats than either the white or red varieties. Oleic, linoleic, and palmitic were the primary fatty acids in all three analysed sorghum varieties. Significant differences in mineral content were found among the samples with a greater amount of Mg, K, Al, Mn, Fe, Ni, Zn, Pb and U in both red and black than the white sorghum variety. The results show that sorghum whole grain flour made from grain with varying pericarp colours contains unique nutritional properties.

Long-term outcomes after lung-sparing surgery for epithelial mesothelioma.

BACKGROUND: This observational study evaluates retrospectively the long-term outcomes after pleurectomy/decortication for pleural mesothelioma, with and without the resection/reconstruction of diaphragm and pericardium. METHODS: Data from 155 consecutive patients undergoing lung-sparing surgery for epithelial pleural mesothelioma were reviewed. Selection criteria for surgery were cT1-3, cN0-1, good performance status, age <80 years. Perioperative Pemetrexed-Platinum regimen was administered as induction in 101 cases (65.2%) and as adjuvant treatment in 54 cases (34.8%). Extended pleurectomy/decortication was performed in 87 cases (56.12%). In 68 patients (43.87%) standard pleurectomy/decortication was performed without resection/reconstruction of diaphragm and pericardium, when tumour infiltration was deemed absent after intraoperative frozen section. The log-rank test and Cox regression model were used to assess the factors affecting overall survival and recurrence free survival. RESULTS: Median follow-up was 20 months. The 2- and 5-year survival rate was 60.9% and 29.2% with a median survival of 34 months. An improved survival was observed when standard pleurectomy/decortication was carried out (P=0.007). A significant impact on survival was found comparing the TNM-stages (P=0.001), pT (P=0.002) and pN variables (P=0.001). Multivariate analysis identified the pN-status (P=0.003) and standard pleurectomy/decortication (P=0.017) as predictive for longer survival. The recurrence-free survival >12 months was strongly related to the overall survival (P<0.001). The macroscopic complete resection (P=0.001), TNM-stage (P=0.003) and pT-status (P=0.001) are related to relapse. CONCLUSIONS: Within multimodal management of pleural mesothelioma, lung-sparing surgery is a valid option even with more conservative technique. A benefit for a longer survival was observed in the early stage of disease, with pN0 and when pleurectomy/decortication is carried out, preserving diaphragm and pericardium. Recurrence is not affected by the type of surgery, and a recurrence-free interval >12 months is predictive of an increased survival when the macroscopic complete resection is achieved.

Predictors of behaviour in solitary fibrous tumours of the pleura surgically resected: Analysis of 107 patients.

OBJECTIVES: Gold standard therapy for solitary fibrous tumour of the pleura is complete surgical resection. Aims of this retrospective study are to evaluate oncological and surgical outcomes and to verify the clinical reliability of prognostic scores presented in literature. METHODS: Study population: 107 patients surgically treated between 1972 and 2018. Male/female ratio: 1/2.45; median age at surgery: 60 years (range, 19-80); peduncle lesions 69.8%; visceral pleura origin 72.9%; benign histology 73.8%; median diameter 8 cm (range 1 to 35, 27 cases giant [≥15 cm]). RESULTS: After a median follow up of 7 years, 12 patients had recurrence. By multivariate analysis, malignant histology (P = .03; HR, 4.17; 95% CI, 1.15-15.06), origin from parietal pleura (P = .03; HR, 3.90; 95% CI, 1.08-14.09), England (P = .002; HR, 1.98; 95% CI, 1.28-3.07), Diebold (P = .008; HR, 1.96; 95% CI, 1.20-3.22) and Tapias (P = .003; HR, 1.75; 95% CI, 1.20-2.53) scores were found independent significant predictors of relapse. Giant tumours were associated with open surgery (P = .003), origin from parietal pleura (P = .011) and intraoperative bleeding (P > .001). Overall 10-year disease-free survival (DFS) rate was 81%. Predictors of worst DFS were parietal pleura origin (P = .002), malignant histology (P = .006) and all the prognostic scores. CONCLUSIONS: Malignant histology and origin from parietal pleura were significant predictors of tumour recurrence and worst DFS. The use of current scoring systems can help to predict clinical behaviour. Patients with higher risk of relapse can benefit from closer follow up, prolonged over 10 years.

Vertical, electrolyte-gated organic transistors show continuous operation in the MA cm-2 regime and artificial synaptic behaviour.

Until now, organic semiconductors have failed to achieve high performance in highly integrated, sub-100 nm transistors. Consequently, single-crystalline materials such as single-walled carbon nanotubes, MoS2 or inorganic semiconductors are the materials of choice at the nanoscale. Here we show, using a vertical field-effect transistor design with a channel length of only 40 nm and a footprint of 2 × 80 × 80 nm2, that high electrical performance with organic polymers can be realized when using electrolyte gating. Our organic transistors combine high on-state current densities of above 3 MA cm-2, on/off current modulation ratios of up to 108 and large transconductances of up to 5,000 S m-1. Given the high on-state currents at such large on/off ratios, our novel structures also show promise for use in artificial neural networks, where they could operate as memristive devices with sub-100 fJ energy usage.

Transferable Organic Semiconductor Nanosheets for Application in Electronic Devices.

A method has been developed to stabilize and transfer nanofilms of functional organic semiconductors. The method is based on crosslinking of their topmost layers by low energy electron irradiation. The films can then be detached from their original substrates and subsequently deposited onto new solid or holey substrates retaining their structural integrity. Grazing incidence X-ray diffraction, X-ray specular reflectivity, and UV-Vis spectroscopy measurements reveal that the electron irradiation of ≈50 nm thick pentacene films results in crosslinking of their only topmost ≈5 nm (3-4 monolayers), whereas the deeper pentacene layers preserve their pristine crystallinity. The electronic performance of the transferred pentacene nanosheets in bottom contact field-effect devices is studied and it is found that they are fully functional and demonstrate superior charge injection properties in comparison to the pentacene films directly grown on the contact structures by vapor deposition. The new approach paves the way to integration of the organic semiconductor nanofilms on substrates unfavorable for their direct growth as well as to their implementation in hybrid devices with unusual geometries, e.g., in devices incorporating free-standing sheets.

Real surgical morbidity and mortality after extrapleural pneumonectomy.

As for other major thoracic operations the conventional 30-day morbidity and mortality marker may underestimate the actual surgical risk of extrapleural pneumonectomy. We retrospectively analysed the prolonged follow-up of 78 patients submitted to extrapleural pneumonectomy for pleural mesothelioma (55), lung cancer with associated carcinomatous (7) or purulent (8) pleuritis, empyema/destroyed lung (4), and mediastinal (2) and chest wall (2) tumours with pleuro-pulmonary involvement. Significant rates of surgery-related major complications (19%) and fatalities (6.6%) additionally occurred beyond 30 days and within 6 months of extrapleural pneumonectomy, making a 66% cumulative (early + late) morbidity rate and an 11.5% cumulative mortality rate, which are respectively 50% and 100% greater than the 30-day rate alone. The leading causes of late morbidity and mortality were respiratory/cardiac sequelae (50%) and broncho-pleural fistulas (30%). Strict preoperative functional selection and proper application of the technical learning curve can reduce the occurrence of the adverse events by anything up to 50% (early mortality: 2.3%). If the results of this novel study of long-term surgical outcomes of extrapleural pneumonectomy were to be confirmed, the preoperative risk/benefit balance of the procedure, mainly when performed for thoracic malignancies, should therefore include the entire spectrum of (early and late) potential surgery-related complications.

Intraoperative identification and effective "blood patch" prevention of persistent air leak in lung resections.

Persistent air leak (PAL) is the most common complication after lung resection, requiring additional treatments and hospital stay. Intraoperative prevention of PAL is usually left to the surgeon's subjective judgement, with inconsistent results. The aim of the study was to establish systematic, reproducible quantification of air leaks at thoracotomy in order to identify those which are potentially persistent, to be preventively treated by intraoperative "blood patch" pneumo-stasis. In a consecutive series of 570 lung resections, parenchymal suture air tightness was tested intraoperatively at end-inspiratory pressure intervals from 15 to 35 cm H2O. Air leaks at 15 cm H2O (n=40) were considered too critical, while air escape beyond 30 cm H2O (n=437) was deemed quickly self-sealing postoperatively; these conditions were managed by further surgery and standard chest tubes only, respectively. Air leaks between 16 and 30 cm H20 (n=93) were assumed to be the main source of postoperative PAL and were preventively treated with 50 cc of blood left in the cavity for 3 hours after closing the thoracotomy. Chest tubes were set up so as to avoid tension pneumothorax or occult bleeding. No early or late major complications were related to the intraoperative "blood patch" procedure. The cumulative incidence of PAL was 1.4%, most of which (6/8) belonging to the group leaking air in the 16-30 cm H2O pressure interval. In contrast, the PAL rate in the 437 patients reputed to be at low risk was 0.2%. The overall mean hospital stay was 7.2 days, the mean duration of chest tube duration 3.5 days, and the complication rate 15%. According to our retrospective data, air leaks occurring between 16 and 30 cm H2O of pressure in the intubated lung were identified as carrying the highest risk of becoming persistent postoperatively; intraoperative "blood patch" pneumo-stasis is a convenient and successful preventive method to minimize PAL occurrence in this group of patients.

Evaluation and improvement of the efficiency of the Seidel humeral nail by numerical-experimental analysis of the bone-implant contact.

Seidel intramedullary humeral nail is locked distally by a spreading device and proximally by transverse cross locking screws. The main problems found in its use are: the loosening of the distal anchorage, even after X-ray verification of the correct expansion of the device; the formation of distal fractures, occurring even 1 month after the operation; the system's low stability. The problems noted can be ascribed to the behaviour of the spreading device for distal fixing. The present study, therefore, was directed at analysing the contact between the spreading mechanism and the medullary canal in relation to the geometric parameters of the mechanism itself. The main objective was to define the correct regulation of the expansion in the operating theatre, and to delimit the more appropriate conditions of use, allowing the surgeon to evaluate the suitability of this particular device for the type of fracture under treatment. Numerical and experimental techniques were used to perform an analysis of the implant behaviour. This investigation, referred to immediate post-operative condition, allowed to evaluate the stability to traction of the system, to define the typology and properties of the bone-implant contact zone and to quantify the stresses produced, all as a function of the parameter on which the surgeon intervenes in the operating theatre: the number of turns used to tighten the spreading screw. The results obtained confirm and explain the disadvantages associated with the distal expansion system: the bone-implant contact turns out to be inefficient, as revealed by the distribution of the pressure on the inner wall of the medullary canal. On the basis of the results, it is possible to define the optimal conditions of use of the nail, and to formulate a simple solution for the improvement of its performance.

Surgical outcome of lung cancer patients with carcinomatous pleuritis.

In sporadic though non-anecdotal series, long-term survival has been reported for patients operated on for lung cancer with secondary carcinomatous pleuritis. In a retrospective study, we review the outcomes of 24 surgical patients (20 treated with standard lung resection +/- pleurectomy and 4 with extended pleuropneumonectomy) out of 48 individuals affected by pleural spread before or at thoracotomy. We observed a 16.6% major complication rate with no operative mortality; 5-year and median survival were 20% and 21 months, respectively. Time of diagnostic (pre- vs intra/postoperative) or pattern (effusion vs dissemination) of pleural disease, and type of resection (standard vs extended) did not seem to influence the prognosis, while an adenocarcinoma histotype, completeness of excision and N(0-1) were favourable prognostic indicators. Since most (90%) of these IIIB stages are usually associated with N(2-3) and/or unresectable tumour, it would seem reasonable to employ neo-adjuvant treatment as the first approach, reserving surgical treatment to responders. Multicentre studies are necessary to better determine which subgroup of patients with malignant pleuritis can most benefit from surgical therapy.

Assessment of outcomes in typical and atypical carcinoids according to latest WHO classification.

BACKGROUND: Pulmonary carcinoid tumors represent a group of malignant neoplasms comprised of neuroendocrine cells. In 1999, the World Health Organization (W.H.O.) proposed the definitive classification of neuroendocrine tumors based on the criteria from Travis and associates. The W.H.O. described two different groups of carcinoid tumors: typical carcinoids (TC) and atypical carcinoids (AC). Few reports have reviewed their data according to the current classification, and therefore, prognosis and standard therapy for TC and AC are still uncertain. METHODS: From 1980 to 2001, 98 pulmonary resections have been performed for primary bronchial carcinoid tumors in our Thoracic Department of the University of Milan. We reviewed original histology using the current W.H.O. criteria and identified 88 patients with TC and 10 with AC. We reviewed the outcomes in each group. RESULTS: The 5 year-overall survival rate was 91.9% for TC and 71% for AC. The 10-year overall survival rate was 89.7% for TC and 60% for AC. The 5-year TNM-related survival rates in the TC group were: IA-B, 100%; IIA-B, 75%; and IIIA, 50%. At 10 years, they were: IA-B, 100%; IIA-B, 75%; and IIIA, 0%. The 5-year survival rates in the AC group were: IA-B, 100%; IIA-B, 100%; and IIIA, 0%. At 10 years, they were: IA-B, 100%; IIA-B, 66%; and IIIA, 0%. CONCLUSIONS: Prognosis is favorable for both subtypes in the early stage. Advanced stages are related to better prognosis in TC. Recurrences rate is worse in the AC subtype. Our data suggest avoiding limited resections when feasible in AC. Parenchyma-sparing resections should be encouraged in TC.

Surgical experience of 15 solitary benign fibrous tumor of the pleura.

OBJECTIVE: The localized benign fibrous tumor of the pleura represents 8% of all benign pathologies of the chest and 10% of neoplasms of the pleura. The authors review the literature, and report on 15 cases of localized benign fibrous tumors of the pleura surgically treated over a period of 15 years to further knowledge of this pathology, its therapy and prognosis. METHODS: With respect to the well-known diffuse malignant mesothelioma, different etiopathogenesis, prognosis, and therapeutic approaches characterize the localized benign fibrous tumor of the pleura. In our experience, 15 patients underwent thoracotomy with excision of a pathological endothoracic mass, then histologically proved to be a localized benign tumor of the pleura. The whole group underwent pre-operative evaluation and, when clinic suggested, stadiation and post-operative frequent follow-up. RESULTS: The whole group of 15 patients underwent surgical approach well tolerated the surgical treatment with perfect recovery of post-operative respiratory function. There was no relapse of disease in any patients. At the moment all patients are still alive except one dead of heart failure. CONCLUSION: The differential diagnosis of benign fibrous tumor of the pleura and lung and pleural malignancy depends upon immunohistochemistry of the surgical specimen so that prognosis could be formulated only after surgery. We consider surgery as the treatment of choice in this pathology.

Personal experience in lung cancer sleeve lobectomy and sleeve pneumonectomy.

BACKGROUND: Sleeve lobectomy (SL) and tracheal sleeve pneumonectomy (TSP) represent valuable alternative techniques to standard resections in the treatment of benign and malignant conditions of the airway and allow preservation of lung parenchyma. METHODS: Eighty-three sleeve lobectomies and 27 tracheal sleeve pneumonectomies have been performed for nonsmall cell lung cancer in the thoracic department of the University of Milan from 1979 to 1999. There were 46 upper right lobectomies, 11 upper and middle lobectomies, 18 upper left lobectomies, 8 lower left lobectomies, and 27 right pneumonectomies. RESULTS: Mortality rate was 3.6% in SL and 7.4% in TSP. Complications were 10.8% of all SLs and 15% of all TSPs. The overall 5-year survival rate was 43% for SL and 20% for TSP; the 10-year survival rate was 34% and 14%, respectively. There was a highly significant difference in survival between patients with N0 and N1-N2 disease. CONCLUSIONS: Sleeve lobectomy is an appropriate surgical procedure and an alternative to pneumonectomy in patients with limited respiratory reserve whenever the situation permits. Trachael sleeve pneumonectomy is associated with more complications and poor survival.