1,354,129 research outputs found
PRIMARY NONAMPULLARY DUODENAL ADENOCARCINOMA
No full textL'adenocarcinoma del duodeno e' una rara patologia che rappresenta circa lo 0.3-0.5 % di tutte le neoplasie maligne del tratto gastroenterico.
Malgrado il duodeno rappresenta meno del 10 % della totale lunghezza dell'intestino tenue, circa il 45% delle neoplasie dell'intestino tenue si presentano nel duodeno.
Essendo i sintomi dei questa malattia non specifici la diagnosi di carcinoma del duodeno e' molto difficile e molto spesso tardiva. Tuttavia il carcinoma del duodeno ha una sopravvivenza a 5 anni per tumori resecati tra il 25 e il 75%.
Nell'ultimo decennio differenti studi hanno identificato diversi fattori prognostici associati alla sopravvivenza. Questi studi hanno mostrato che il grado istologico, le dimensioni del tumore,il coinvolgimento transmurale e dei linfonodi possono influenzare la sopravvivenza.
L'obbiettivo di questa tesi e' di migliorare la conoscenza di specifici fattori prognostici associati alla sopravvivenza in pazienti affetti da adenocarinoma primario del duodeno.
Tramite uno studio retrospettivo , 37 pazienti con diagnosi di adenocarcinoma del duodeno tra il 1989 e il 2009 sono stati identificati tramite il database del dipartimento di Chirurgia B dell'Universita' di Verona. Dall'analisi dei dati e' risultato che le complicanze operatorie possono influenzare in maniera significativa la sopravivenza in pazienti affetti da adenocarcinoma del duodeno.Primary Adenocarcinoma of the duodenum is a rare condition, accounting between 0, 3% and 0, 5% of all gastrointestinal malignancies .
Despite the duodenum is representing less than 10 % of the total length of the small bowel, this organ is the site of between 25% and 45% of the small bowel cancers 4. However cancer of the duodenum appeared to be more frequent in the proximity of the Ampulla of Vater periampullary area , about 45 % of them demonstrated to arise in third and in fourth por-tions of this organ. Since the symptoms of this cancer are non-specific and similar to other benign conditions, the diagnosis is often difficult and delayed.
Nonetheless, duodenal carcinoma has a reported 5-year survival rate for resected tumours between 25% and 75% which is significantly better than that for cancer of the ampulla (46%) and the head of pancreas (10%) .
In the last decade different studies evaluated the correlations between clinical, pathological and treatment variables in order to identified specific prognostic factors associated with survival .
Those recent studies showed that histological grade, transmural involvement, tumour size, lymph node involvement and distant metastasis can influence the survival in patients with duodenal adenocarcinoma.
However, due to a low incidence of this disease in the general population, the debate on prognostic factors in duodenal adenocarcinoma is still open. Therefore, questions have been raised especially on the prognostic significance of the absolute number and ratio of involved lymph nodes. A recent study has led an increased interest on perineural invasion as single independent prognostic factor for patients with primary duodenal cancer .
Aims of research
The aim of this thesis was to improve understanding of specific prognostic factors associated to survival in primary duodenal adenocarcinoma.
A retrospective review of 37 patients diagnosed with primary duodenal adenocarcinoma between 1989 and 2009 was performed at Hepato-pancreatico-biliary department, General Surgery B, Verona University, Borgo Roma Hospital. Data were acquired then analysed for impact on recurrence and 5-year overall survival rate.
From this retrospective study, , the development of postoperative complications is an additional prognostic factor after potentially curative resection for primary duodenal adenocarcinoma. This emphasized the need for centralization to high-volume centres, where an appropriate postoperative care can be delivered
Kraft liquor corrosivity - determination of sulfur compounds. Project 2926-56 report two : a progress report to the members of the Institute of Paper Chemistry
No full text"February 19, 1982.""Institute of Paper Chemistry ... Nadia Tonsi-Eldakar ... Michael S. Heath ... David P. Kielpikowski.
RECOVERY AND SEPARATION PROCESSES IN THE RECYCLING CHAIN OF POLYAMIDE PLASTIC MATERIALS TO OBTAINECO-SUSTAINABLE RAW MATERIALS
No full textThe rise of fast fashion and the growing accumulation of mixed textile and plastic waste are creating serious environmental and economic challenges. In particular, polyamides, commonly used in technical textiles and plastics, are often blended with other polymers, making recycling difficult. Traditional methods such as mechanical processing or depolymerization often fail when dealing with these complex mixtures, due to degradation, contamination, or the need for extensive purification. This PhD research, carried out in collaboration with Radici InNova s.c.a r.l. (Radici Group), focused on developing and optimizing a solvent-based recycling process to selectively recover polyamide from post-industrial and post-consumer textile and plastic waste.
The process, known as selective dissolution, involves the use of a specific solvent or solvent mixture to dissolve only the target polymer (polyamide) from a complex material. The other components, such as polyurethane or polyester, remain undissolved and are removed by filtration. The dissolved polyamide is then recovered from the solution by changing the solvent conditions (for example, by adding water as an anti-solvent or by evaporating the solvent), allowing the polymer to re-precipitate in a purified form.
Two solvent systems (solvents A and B) were selected for in-depth study based on a literature review and preliminary experimental screening. These solvents were chosen for their ability to dissolve PA while maintaining selectivity over other polymers. Experimental work showed that both solvents were effective, but solvent B allowed better separation, reducing contamination and preserving the possibility to reuse PU. Moreover, by adjusting the composition of the solvent mixture, it was possible to tune the selectivity of the process, either favouring the dissolution of polyamide or the extraction of polyurethane. This tunable selectivity was demonstrated through systematic tests on PA6, PA66, and PU fibers, using controlled solvent B/water ratios and analysing the dissolution temperatures of each sample. The solubility behaviour was mapped in relation to solvent composition, helping to define process windows for each target polymer. Different types of waste were tested.
Various methods were tested to recover PA from the solution, including anti-solvent crystallization, direct evaporation, and spray drying. Anti-solvent precipitation produced a purer polyamide, with limited molecular degradation and mechanical properties comparable to those required for textile applications. Evaporation resulted higher polymer degradation and in a more flexible materials, likely due to the presence of residual low-molecular-weight compounds acting as plasticizers. Spray drying offered rapid solvent removal but posed challenges in terms of polymer degradation and system clogging, especially with PA-rich solutions.
All samples were extensively characterized to assess their chemical integrity and applicability: intrinsic viscosity, end-group analysis (–NH2 and –COOH), infrared spectroscopy, and differential scanning calorimetry (DSC) were used to determine degradation and purity. In selected cases, the recovered PA was also tested for mechanical performance through tensile strength and impact resistance measurements on injection-moulded specimens, without blending with virgin polymer. The results confirmed that the recycled PA showed good performance.
Special attention was given to solvent recovery, which is essential for the environmental and economic sustainability of the process. For the water–solvent A mixture, both simple and multi-stage distillation were tested, showing good efficiency and the possibility of solvent reuse. Both the impurities accumulating in the reboiler and in the distillate were characterized by GC-MS and TOC analyses. Tests were also carried out to evaluate both the direct reuse of the distillation bottom and the complete purification of the glycol through total solvent evaporation. For solvent B, azeotropic distillation using an entrainer was developed to improve separation and reduce losses. Process simulations using AVEVA Pro/II helped design the distillation systems and confirm the experimental results, especially in terms of tray number, reflux ratio, and entrainer recovery. The use of azeotropic distillation proved advantageous over traditional binary separation, both in terms of energy consumption and solvent purity.
Finally, a Life Cycle Assessment (LCA) was conducted to evaluate the environmental performance of the process. Two process options were compared: anti-solvent precipitation and direct evaporation. Both showed much lower impacts than virgin PA production, with the evaporation route performing slightly better in most categories. The potential reuse of polyurethane and the efficient solvent recovery helped improve the overall sustainability. Contribution analysis highlighted the influence of steam consumption and solvent losses, underlining the importance of process optimization for full-scale implementation.
This research shows that selective dissolution is a promising method for recycling nylon-based textiles and plastics. It allows recovery of high-quality PA and offers a feasible path towards more circular and sustainable production. A patent application has been filed, and scale-up activities are currently underway, including pilot plant development studies and additional research on solvent recovery under the RE-POLY.AI project
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dairy by-products valorization with biomethane and biohydrogen production through lactose fermentation in AnMBR
No full textDairy liquid by-products after cheese production (e.g. whey for hard cheese, “scotta” for ricotta, brine for mozzarrella, lactose syrup after milk standardization by ultrafiltration) represent a potential revenue for food factories where large scale industrial production is implemented, as additional ingredients may be recovered, transformed and sold as separate products. Still, these by-products may also represent a problem for small/medium size factories or in areas that are far from ingredients transformation platforms: complete processing of smaller volumes or shipping liquids over long distances is not convenient. By-products are often disposed as waste, generating unproductive cost for the factory and worsening environmental footprint. In this paper a simple closed loop solution is evaluated for full valorization of those by-products, based on the technologies of: protein separation/concentration and anaerobic treatment of the lactose containing permeate
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Nylon Recycling Processes: a Brief Overview
No full textPlastic pollution is a significant environmental issue, and recycling has been identified as one of the ways to reduce its impact. This review provides therefore a brief overview of the various processes involved in recycling of polyamide plastic waste. Nylon is a material extensively utilized in the creation of clothes, textiles, and other products thanks to its high mechanical and thermal properties, as well as its strength and durability. This latter feature turns in a very slow decomposition if polyamide-based objects are abandoned in the environment, making it a significant environmental pollutant. The review covers all the possible recycling processes for this material, that are mechanical recycling, which involves shredding and melting plastic waste to make new products, solvent dissolution, where a solvent selectively dissolved only the desired polymer leaving behind the unwanted impurities, and chemical recycling, which uses chemical reactions to break down plastic waste into its chemical constituent parts, i.e. Monomers. The advantages and limitations of these processes are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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