MRI-based experimentations of fingertip flat compression: Geometrical measurements and finite element inverse simulations to investigate material property parameters

Modeling human-object interactions is a necessary step in the ergonomic assessment of products. Fingertip finite element models can help investigating these interactions, if they are built based on realistic geometrical data and material properties. The aim of this study was to investigate the fingertip geometry and its mechanical response under compression, and to identify the parameters of a hyperelastic material property associated to the fingertip soft tissues.Fingertip compression tests in an MRI device were performed on 5 subjects at either 2 or 4 N and at 15° or 50°. The MRI images allowed to document both the internal and external fingertip dimensions and to build 5 subject-specific finite element models. Simulations reproducing the fingertip compression tests were run to obtain the material property parameters of the soft tissues.Results indicated that two ellipses in the sagittal and longitudinal plane could describe the external fingertip geometry. The internal geometries indicated an averaged maximal thickness of soft tissues of 6.4 ± 0.8 mm and a 4 ± 1 mm height for the phalanx bone. The averaged deflections under loading went from 1.8 ± 0.3 mm at 2 N, 50° to 3.1 ± 0.2 mm at 4 N, 15°. Finally, the following set of parameters for a second order hyperelastic law to model the fingertip soft tissues was proposed: C₀₁ = 0.59 ± 0.09 kPa and C₂₀ = 2.65 ± 0.88 kPa.These data should facilitate further efforts on fingertip finite element modeling.     

One-step partial or complete caries removal and bonding with antibacterial or traditional self-etch adhesives: study protocol for a randomized controlled trial

BackgroundCurrent concepts in conservative dentistry advocate minimally invasive dentistry and pulp vitality preservation. Moreover, complete removal of carious dentin in deep carious lesions often leads to pulp exposure and root canal treatment, despite the absence of irreversible pulp inflammation. For years, partial caries removal has been performed on primary teeth, but little evidence supports its effectiveness for permanent teeth. Furthermore, the recent development of new antibacterial adhesive systems could be interesting in the treatment of such lesions. The objectives of this study are to compare the effectiveness of partial versus complete carious dentin removal in deep lesions (primary objective) and the use of an antibacterial versus a traditional two-step self-etch adhesive system (main secondary objective).Methods/DesignThe DEep CAries Treatment (DECAT) study protocol is a multicenter, randomized, controlled superiority trial comparing partial versus complete caries removal followed by adhesive restoration. The minimum sample size required is 464 patients. Two successive randomizations will be performed (allocation ratio 1:1): the first for the type of excavation (partial versus complete) and the second (if no root canal treatment is required) for the type of adhesive (antibacterial versus traditional). For the two objectives, the outcome is the success of the treatment after 1 year, measured according to a composite outcome of five FDI criteria: material fracture and retention, marginal adaptation, radiographic examination (including apical pathologies), postoperative sensitivity and tooth vitality, and carious lesion recurrence.DiscussionThe study will investigate the interest of a conservative approach for the management of deep carious lesions in terms of dentin excavation and bioactive adhesive systems. The results may help practitioners achieve the most efficient restorative procedure to maintain pulp vitality and increase the restoration longevity.

Trial registration

ClinicalTrials.gov Identifier {"type":"clinical-trial","attrs":{"text":"NCT02286388","term_id":"NCT02286388"}}NCT02286388. Registered in November 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1484-0) contains supplementary material, which is available to authorized users.     

Effects of ionic substances in bleaching filtrates and of lignosulfonates on the activity of oxalate oxidase from barley

The effects of ionic substances in seven industrial filtrates from kraft pulping, mechanical pulping, and sulfite pulping on the activity of oxalate oxidase from barley were investigated by pre‐treatment of the filtrates with ion‐exchange resins prior to enzymatic degradation of the oxalic acid in the filtrates. The pre‐treatment resulted in increased oxalic acid degradation rates in all filtrates, except for one that was obtained from sulfite pulping. The possibility that lignosulfonates, which were present in the filtrate from sulfite pulping, could affect oxalate oxidase was investigated in a separate set of experiments involving four different preparations of lignosulfonates. At a lignosulfonate concentration of 50 mg/mL and a pH of 3.8, only 2–16% of the activity of oxalate oxidase remained. The results show the effects of anionic and cationic substances in bleaching filtrates on oxalate oxidase and indicate that there is an interaction between the enzyme, which has a positive net charge at pH 3.8, and the polymeric anionic lignosulfonates.     

Influence of variables in the hydrothermal treatment of rice straw on the composition of the resulting fractions

The influence of the hydrothermal treatment conditions of rice straw (temperature – 150–190 °C , time – 0–20 min after reaching the operation temperature – and liquid/solid ratio – 6–8), on the composition of liquid and solid fractions was studied. Polynomial models were found for to reproduce the experimental results with errors less than 6%.     

Characterization of cotton fabric nanocomposites with in situ generated copper nanoparticles for antimicrobial applications

Abstract

In the present study, cotton fabric nanocomposites with in situ generated copper nanoparticles (CuNPs) were prepared using Cassia alata leaf extract as reducing agent. The prepared cotton fabric nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscoy (SEM) techniques. The cotton fabric nanocomposites exhibited significant antibacterial activity against Escherichia coli bacteria. These nanocomposites retained the antibacterial activity even after 15 washes indicating the generation of permanent CuNPs in them. The antibacterial activity of the nanocomposites prepared even in sewerage water was also studied. The obtained results suggest that the cotton fabric nanocomposites with in situ generated CuNPs can be considered for medical and water treatment applications.     

Production of pulp and energy using orange tree prunings

The aim of this work was to chemically characterize orange tree prunings and use it in pulping and combustion processes. Soda-anthraquinone pulping of the main fraction of orange pruning (stems with a diameter > 0.5 cm) was simulated with polynomial and neurofuzzy models, that predicted pulp properties as a function of operating variables (155-185°C, 40-90 min, soda concentration, 10-16%) with errors less than 20%. The heating values (16,870 kJ/kg), the flame temperature (1150-2150 °C) and dew point temperature of fuel gas (47-53 °C) for the residual fraction from orange pruning (stems diameter < 0.5 cm and leaves) was determined and compared with other non-wood lignocellulosic materials. As a consequence the price of kJ obtained by combustion of this residual fraction is less than other lignocellulosic materials, much lower than those of fossil fuels.     

Towards industrially-feasible delignification and pitch removal by treating paper pulp with Myceliophthora thermophila laccase and a phenolic mediator

The ability of two natural phenols to act as mediators of the recombinant Myceliophthora thermophila laccase (MtL) in eucalypt-pulp delignification was investigated. After alkaline peroxide extraction, the properties of the enzymatically-treated pulps improved with respect to the control. The pulp brightness increased (3.1 points) after the enzymatic treatment with MtL alone, but the highest improvements were obtained after the MtL treatment using syringaldehyde (4.7 points) and especially methyl syringate (8.3 points) as mediators. Likewise, a decrease in kappa number up to 2.7 points was obtained after the MtL-methyl syringate treatment, followed by decreases of 1.4 and 0.9 points after the treatments with MtL-syringaldehyde and MtL alone, respectively. On the other hand, removal of the main lipophilic extractives present in eucalypt pulp was observed after the above laccase-mediator treatments. Finally, the doses of both MtL and methyl syringate were reduced, and results compatible with industrial implementation were obtained.     

The role of angiogenesis and pulpal healing in tooth replantation and allograft transplantation

Tooth transplantation is one of the treatment options for extracted teeth that can be considered before dental implantation. Although the success rate of tooth transplantation is lower than that of implantation, tooth replantation and transplantation have the great advantage of using natural teeth. Tooth replantation might be considered a promising option in some cases. In present study, the expression patterns of revascularization and pulpal healing, which are the most important for the pulp viability, were analyzed after tooth replantation and allograft in mice. The inflammatory response and root dentin resorption were observed and not different between replantation and allograft in initiation of healing process. However, bonelike tissue formation, pulp revascularization and pulp healing were faster in replantation. The difference of healing patterns between tooth replantation and allograft found in present study will be helpful to select the treatment option and to understand healing mechanism.     

岩溶区不同根系地下生境类型白栎叶片δ13C值的变化

选取岩溶区白云岩低倾产状多层空间类型、中倾产状多层空间类型及高倾产状多层空间类型3种根系地下生境类型中生长的优势树种白栎为对象,研究白栎叶片的δ¹³C值及其与各类型生境中土壤条件的关系,以及白栎水分利用效率.结果表明： 3种类型中的白栎叶片δ¹³C值存在显著差异,表现为低倾产状多层空间类型(-26.35‰)>高倾产状多层空间类型(-26.66‰)> 中倾产状多层空间类型(-27.07‰),白栎水分利用效率依次降低;白栎叶片的δ¹³C值与根系地下生境类型中土壤水分含量显著相关,但与土壤元素含量相关性不显著;δ¹³C值随土壤水分含量和肥力水平的减少而增加.     

A review of the chemistry and uses of crocins and crocetin,the carotenoid natural dyes in saffron,with particular emphasis on applications as colorants including their use as biological stains

The perennial flowering plant, saffron crocus (Crocus sativus L.), is the source of the most expensive spice in the world. The dried stigmas of saffron flowers are the source of a natural dye, saffron, which has been used from ancient times for dyeing silk and fabric rugs, and for painting; it also has been used for cooking and in medicine. The yellow compounds present in the dye include crocins, which are 20-carbon water soluble glycosyl derivatives of the carotenoid, crocetin, and the dicarboxylic acid itself. We review the chemistry of these compounds and discuss various applications of saffron as a natural dye. We review in particular the use of saffron or its constituents in histopathologic techniques.