In the present paper a new additive manufacturing processing route is introduced for ultra-high performance concrete. Interdisciplinary work involving materials science, computation, robotics, ...architecture and design resulted in the development of an innovative way of 3D printing cementitious materials. The 3D printing process involved is based on a FDM-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a 6-axis robotic arm. The mechanical properties of 3D printed materials are assessed. The proposed technology succeeds in solving many of the problems that can be found in the literature. Most notably, this process allows the production of 3D large-scale complex geometries, without the use of temporary supports, as opposed to 2.5D examples found in the literature for concrete 3D printing. Architectural cases of application are used as examples in order to demonstrate the potentialities of the technology. Two structural elements were produced and constitute some of the largest 3D printed concrete parts available until now. Multi-functionality was enabled for both structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale additive manufacturing.
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•A novel large-scale 3D printing process is proposed for cementitious materials.•Structures with complex geometry are produced without temporary supports.•The tangential continuity method for slicing is used, providing mechanical stability.•3D-printed concrete structures produced are some of the largest available today.•Geometric complexity enables multifunctionality and multiscale architecturation.
This study was designed to evaluate the long-term natural history of sigmoid diverticulitis in patients treated nonoperatively after a first acute episode and to assess the role of elective ...colectomy.
Between 1986 and 1991, 144 patients were admitted for acute diverticulitis diagnosed by abdominal computed tomography and had a successful nonoperative treatment. Remote complications (persisting or recurring diverticulitis) were also diagnosed by computed tomography. Patients had a poor outcome if they had one of these complications. Diverticulitis was graded mild or severe on computed tomography according to Ambrosetti's criteria. We determined statistically whether young age (< or =50 years old) and severe diverticulitis were risk factors for a poor outcome.
One hundred eighteen patients with a contributive computed tomographic scan at admission were followed up. Median age was 63 (range, 23-93) years, with a median follow-up of 9.5 (range, 0.2-13.8) years. Eighty patients had no complications, and 38 had remote complications. The incidence of remote complications was the highest (54 percent at 5 years) for young patients with severe diverticulitis on computed tomography and the lowest (19 percent at 5 years) for older patients with mild disease. Young age and severe diverticulitis taken separately were both statistically significant factors of poor outcome (P = 0.007 and P = 0.003, respectively), although age was no longer significant after stratification for disease severity on computed tomography (P = 0.07). Twenty-four patients died. The cause of death was unrelated to diverticulitis in 21 cases and unknown in the remaining 3.
We propose that after a first acute episode of diverticulitis treated nonoperatively, elective colectomy should be offered to young patients (< or =50 years old) with severe diverticulitis on computed tomography.
The safety of laparoscopic appendectomy for the management of incidentally discovered appendiceal tumors has not yet been established.
Appendiceal tumor cases managed by laparoscopy or laparotomy ...over a 10-year period were reviewed.
The pathological diagnoses were 23 carcinoid and 20 cancerous lesions. The median patient ages were 36 and 69 years, respectively, for carcinoid and other tumors (p < 0.05). Acute appendicitis was present in 70% of carcinoid cases and 35% of other tumors (p < 0.05). Eight patients with carcinoid tumors were operated on by laparoscopy, whereas 15 underwent laparotomy. Laparoscopic and open procedures were performed in three and 17 patients with cancerous lesions, respectively. Invaded surgical margins were seen after laparoscopy in 20% of patients and open surgery in 6%. Synchronous colon carcinoma was detected in 14% of the patients with an appendix neoplasm. The 5-year survival rates were similar after both laparoscopic and open appendectomy for either carcinoid or other tumors.
Laparoscopic appendectomy for appendiceal tumors seems to have a slightly higher rate of inadequate resection. However, it is not associated with a significantly worse patient prognosis than open appendectomy.
In the area of ornamental horticulture, it is necessary to compare individuals to assess the effect of an experimental treatment or to distinguish between two genotypes. This is especially true for ...the hybrid tea rose, a plant species widely used throughout the world as a garden rose and represented by a very large number of cultivars. Normally, this diversity is approached by a more or less subjective analysis of the shape, with terms such as upright or spreading, and compact vs. laxly branched. Even when evaluated by a panel of experts, this approach quickly reaches its limits when it is necessary to objectively quantify the differences observed. The architectural analysis proposed here allows us to satisfy this objective. Two rose genotypes were studied:
Rosa hybrida ‘Radrazz’ Knock-Out
® (KO) and ‘Meiratcan’, Lovely Meilland
® (LM). These two genotypes share both architectural similarities and differences. As for the similarities: (i) the axes are of two highly differentiated types, long and short; (ii) the proportions of each type of axis vary from 100% of long axes for order 1, to 100% of short axes for the last branching order; and (iii) all of the flowering axes have a comparable profile, with the continuous development of their morphological components, from their base to their extremity. Despite these similarities, the two genotypes are very clearly differentiated. The number of orders and axes is greater for KO, whereas axis length and the number of metamers per axis are much greater for LM. The architectural analysis proposed here makes it possible to effectively quantify the major shape components of an ornamental plant like the rose. As a result, it provides a truly effective tool for objectively assessing plant shape.
The gastric bypass-induced quantitative and qualitative modifications of energy intake (En In, kcal/day) and their impact on body weight (bw) loss were evaluated. The factors influencing energy ...intake and body weight loss were also investigated.
Longitudinal study.
University Hospital of Geneva.
Fifty obese women undergoing a Roux-en-Y gastric bypass.
The reduction of EnIn was significantly related to bw loss expressed either in kg or as percentage correction of excess bw (P<0.01 for both), whereas the post-operative modifications of diet composition did not play a role. Age and initial bw significantly influenced bw loss (P<0.0001 and P<0.001, respectively), as shown by multiple regression analysis. Patients were divided into four sub-groups according to their age (under or over 35 y) and initial bw (under or over 120 kg). ANOVA showed that under 35-y-old subjects reduced their EnIn significantly more than their older counterparts having similar bw (P<0.02 and P<0.05); consequently, bw loss, expressed in kg, was significantly (P<0.0001 and P<0.0005) larger in younger patients. Subjects with an initial bw over 120 kg lost significantly (P<0.001 and P<0.02) more weight as compared to patients with a smaller degree of obesity (under 120 kg) and similar age.
Gastric bypass-induced body weight loss is mainly due to the reduction of EnIn, whereas the qualitative modifications of the diet do not play a role. Younger subjects have a greater capacity to reduce EnIn and, therefore, lose more weight. Pre-operative high degree of obesity leads to a larger weight reduction, probably because of a greater energy deficit.
Paragangliomas are rare tumours originating from neuroectodermic remnants and are usually considered as benign. We present two cases of paraganglioma of the ampulla of Vater that were treated ...surgically by pancreaticoduodenectomy. In one case, histopathology revealed malignant characteristics of the tumour with invasion of the pancreas and simultaneous duodenal lymph-node metastases. Both patients had a favourable outcome without disease recurrence at 40 and 44 months postoperatively. Only 21 cases of ampullary paraganglioma have been reported in the literature, 7 of them with malignant characteristics. In conclusion, paragangliomas of the ampulla of Vater have malignant potential. Surgical therapy of these tumours should not be limited to local resection, as disease recurrence and lymph node involvement have been reported. We propose that paragangliomas of the ampulla of Vater should be operated by cephalic pancreaticoduodenectomy, which allows long-term and disease-free survival.
CT-scan-guided percutaneous abscess drainage of Hinchey Stage II diverticulitis is considered the best initial approach to treat conservatively the abscess and to subsequently perform an elective ...sigmoidectomy. However, drainage is not always technically feasible, may expose the patient to additional morbidity, and has not been critically evaluated in this indication. This study was undertaken to compare the results of percutaneous drainage vs. antibiotic therapy alone in patients with Hinchey II diverticulitis.
This was a case-control study of all patients who presented in our institution with Hinchey Stage II diverticulitis between 1993 and 2005. Thirty-four patients underwent abscess drainage under CT-scan guidance (Group 1), and 32 patients were treated with antibiotic therapy alone (Group 2), in most cases because CT-scan-guided abscess drainage was considered technically unfeasible by the interventional radiology team. Initial conservative treatment was considered a failure when: 1) emergency surgery had to be performed, 2) signs of worsening sepsis developed, and 3) abscess recurred within four weeks of drainage.
The median size of abscess was 6 (range, 3-18) cm in Group 1 and 4 (range, 3-10) cm in Group 2 (P = 0.002). Median duration of drainage was 8 (range, 1-18) days. Conservative treatment failed in 11 patients (33 percent) of Group 1, and in 6 patients (19 percent) of Group 2 (P = 0.26). Ten patients (29 percent) in Group 1 and five patients (16 percent) in Group 2 underwent emergency surgery (P = 0.24); there were four postoperative deaths (26.6 percent) in this subgroup. Twelve patients (35 percent) in Group 1 and 16 patients (50 percent) in Group 2 subsequently underwent an elective sigmoid resection (P = 0.31). In this subgroup of patients, there was neither anastomotic leakage nor postoperative death.
Emergency surgery for Hinchey Stage II diverticulitis carries a high mortality rate and should be avoided. To achieve this, antibiotic therapy alone seems to be a safe alternative, whenever percutaneous drainage is technically difficult or hazardous. Actually, our data did not demonstrate any benefit of CT scan-guided percutaneous abscess drainage, suggesting that the role of interventional radiology techniques in this indication deserves further critical evaluation.
Re-Os data and PGE concentrations as well as Mo concentrations and isotope data are reported for suites of fine clastic sediments and black shales from the Barberton Greenstone Belt, South Africa ...(Fig Tree and Moodies Groups, 3.25–3.15 Ga), the Belingwe Greenstone Belt, Zimbabwe (Manjeri Formation, ca. 2.7 Ga) and shales from the Witwatersrand, Ventersdorp and Transvaal Supergroups, South Africa ranging from 2.95 to 2.2 Ga. Moderately oxidizing conditions are required to mobilize Re and Mo in the environment, Mo fractionation only occurs in solution, and these parameters thus have potential use as paleoredox proxies for the early Earth.
PGE + Re abundance patterns of Barberton Greenstone Belt sediments are uniform and very similar in shape to those of komatiites. This indicates (1) that the PGE came from a source of predominantly ultramafic composition and, (2) that PGE were transported and deposited essentially in particulate form. Sediments from the younger Belingwe Greenstone Belt show more fractionated PGE + Re patterns and have Re/Os ratios 10 to 100× higher than those of Barberton sediments. Their PGE abundance patterns and Re/Os ratios are intermediate between those of the mid-Archean shales and Neoproterozoic to Recent black shales. They reflect scavenging of Re from solution in the sedimentary environment.
δ
98/95Mo values of black shales of all ages correlate with their concentrations. The Barberton Greenstone Belt samples have ∼1–3 ppm Mo, similar to a granitoid-basaltic source. This Mo has δ
98/95Mo between −1.9 and −2.4‰ relative to present day mean ocean water molybdenum, MOMO and is thus not isotopically fractionated relative to such a source. Similar to the PGE this indicates transport in solid form. Sediments from the Belingwe Greenstone Belt show in part enhanced Mo concentrations (up to 6 ppm) and Mo isotope fractionation (δ
98/95Mo up to −1.4‰ relative to MOMO). The combined PGE + Re and Mo data show mainly reducing conditions in the mid-Archean and suggest that by 2.7 Ga, the atmosphere and oceans had become more oxidizing.
Substantially younger samples from the Transvaal Supergroup (to ca. 2.2 Ga) surprisingly have mainly low Mo concentrations (around 1 ppm) and show no significant Mo isotope fractionation relative to the continental source. Among possible explanations for this are a return to reducing atmospheric conditions after 2.7 Ga, reservoir effects, or Mo removal by sulfide precipitation following sulfate reduction in early Proterozoic oceans.
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