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1.
Polymers (Basel) ; 15(7)2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-37050308

RESUMO

A reliance on fossil fuel has led to the increased emission of greenhouse gases (GHGs). The excessive consumption of raw materials today makes the search for sustainable resources more pressing than ever. Technical lignins are mainly used in low-value applications such as heat and electricity generation. Green enzyme-based modifications of technical lignin have generated a number of functional lignin-based polymers, fillers, coatings, and many other applications and materials. These bio-modified technical lignins often display similar properties in terms of their durability and elasticity as fossil-based materials while also being biodegradable. Therefore, it is possible to replace a wide range of environmentally damaging materials with lignin-based ones. By researching publications from the last 20 years focusing on the latest findings utilizing databases, a comprehensive collection on this topic was crafted. This review summarizes the recent progress made in enzymatically modifying technical lignins utilizing laccases, peroxidases, and lipases. The underlying enzymatic reaction mechanisms and processes are being elucidated and the application possibilities discussed. In addition, the environmental assessment of novel technical lignin-based products as well as the developments, opportunities, and challenges are highlighted.

2.
Polymers (Basel) ; 14(2)2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35054664

RESUMO

This study investigates the effect of the enzymatic polymerization of lignosulfonate for the formulation of a lignosulfonate-based adhesive. For this, beech lamellas were glued together and tested according to the EN 302-1 standard. The results showed that the laccase-polymerized lignosulfonate-based wood adhesives (LS-p) had similar mechanical properties as a standard carpenter's glue (PVAc-based D3 class white glue), as no significant difference in tensile shear strength between these two adhesive types was found. However, carpenter's glue showed almost 100% wood failure, while with the lignosulfonate-based wood glue, the samples failed, mainly in the glueline. Pre-polymerization of LS-p is the most critical factor to achieve the required viscosity, which is also connected to the wetting properties and the resulting tensile shear strength. The longer the pre-polymerization, the higher the viscosity of the LS-p adhesive, with the tensile shear strength reaching a plateau. The presented data show the potential of using enzymatically pre-polymerized lignosulfonate as a well-performing wood adhesive. Further development and optimization of the pre-polymerization process is required, which is also important to push towards upscaling and practical applications.

3.
Strahlenther Onkol ; 178(5): 259-62, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12082685

RESUMO

BACKGROUND: The use of the belly board device (BBD) in the prone position has gained acceptance to spare small bowel in rectal cancer patients irradiated postoperatively, but there are few data in the preoperative setting, and the advantages of the BBD regarding normal tissue sparing may be counteracted by problems of patient positioning. This study was undertaken to investigate prospectively the influence of the BBD on treatment reproducibility in patients irradiated preoperatively in the prone position. PATIENTS AND METHODS: 23 patients with rectal carcinoma in clinical stages II/III were included in this study. Axis displacement was evaluated in 14 patients treated without the BBD and nine with. The BBD is a commercial device (Belly Board, Radiation Products Design, Albertville, MN) made of a 17-cm thick hard sponge with an opening of 42 x 42 cm2. No specific patient immobilization devices were used. During radiotherapy, twelve patients had four control films, while eleven patients had three. The mean treatment position deviation was calculated for the medio-lateral, cranio-caudal and antero-posterior directions. RESULTS: When comparing the first control film to the corresponding simulation film for patients without the BBD and with the BBD, the mean lateral displacements were 1.5 mm and 3.2 mm (p = 0.26), the mean cranio-caudal displacements were 1.55 mm and 4.2 mm (p = 0.13), and the mean antero-posterior displacements were 1.8 mm and 4.5 mm (p = 0.04), respectively. When considering all control films, for the three directions, the amplitudes of the displacements were greater when using the BBD, particularly for the antero-posterior direction where the difference was highly significant (p = 0.0006). CONCLUSIONS: Our data show that, in patients treated prone for rectal cancer, the use of the BBD in the preoperative setting without immobilization devices was associated with problems of patient position reproducibility, particularly for the antero-posterior direction. Thus, the use of patient immobilization devices and/or individual custom-made BBD may be recommended if a decision to treat the patient with a BBD is taken.


Assuntos
Intestino Delgado/efeitos da radiação , Terapia Neoadjuvante , Lesões por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Neoplasias Retais/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Fracionamento da Dose de Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Decúbito Ventral , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Reprodutibilidade dos Testes
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