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1.
Food Chem ; 366: 130559, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34289440

RESUMO

In order to realize rapid and non-destructive detection of hardness for maize kernels, a method for quantitative hardness measurement was proposed based on hyperspectral imaging technology. Firstly, the regression model of hardness and moisture content was established. Then, based on reflectance hyperspectral imaging at wavelengths within 399.75-1005.80 nm, the prediction model of the moisture content was studied by the partial least squares regression (PLSR) based on the characteristic wavelengths, which was selected through successive projection algorithm (SPA). Finally, the hardness prediction model was validated by combing the prediction model of moisture content with the regression model of hardness. The coefficient of determination (R2), the root mean square error (RMSE) the ratio of performance-to-deviation (RPD) and the ratio of error range (RER) of hardness prediction were 0.912, 17.76 MPa, 3.41 and 14, respectively. Therefore, this study provided a method for rapid and non-destructive detection of hardness of maize kernels.


Assuntos
Imageamento Hiperespectral , Zea mays , Dureza , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho
2.
Food Chem ; 371: 131102, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34537616

RESUMO

The effect of egg white protein addition on the fibrous structure and protein aggregation of textured wheat gluten (TWG) extrudates was investigated. The hardness, springiness, chewiness, and degree of texturization of TWG significantly increased with the addition of egg white protein. Analysis of morphological characteristics showed a positive effect of egg white protein on the formation of the fibrous structure of TWG. The results of size-exclusion high performance liquid chromatography (SE-HPLC) indicated that the egg white protein improved the degree of wheat gluten aggregation, and the analysis of the protein intermolecular forces proved that disulfide bonds were the main contributor to the cross-linking of protein. In addition, an increase in the ß-sheets also indicated an increase in protein aggregation induced by egg white protein. The addition of egg white protein promoted protein interactions and improved the fibrous structure of TWG.


Assuntos
Agregados Proteicos , Triticum , Proteínas do Ovo , Glutens , Dureza
3.
Food Chem ; 370: 130962, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34555774

RESUMO

In this study, 0.1% (W/V) sodium bicarbonate (SB) solution was used to soften lotus rhizome, and the mechanism was characterized by monoclonal antibodies labeling (mAbs) and atomic force microscopy (AFM). The results showed that the cell wall of lotus rhizome was disintegrated under SB treatment. In addition, the mAbs results revealed that low-esterified homogalacturonan (HG) at the tricellular junction was degraded, the rearrangement of Ara and the interaction between Gal and cellulose may be related to the texture changes. Compared with distilled water treatment, SB treatment reduced the relative content of pectin from 34.1% to 19.1% while increased that of cellulose from 65.9% to 80.9%. AFM results revealed that the height of CSF skeleton decreased from about 32 nm to 1.5 nm. These results clearly demonstrate that cooking with 0.1% SB can soften lotus rhizome through degradation of pectin and arrangement of side chains of rhamnogalacturonan-Ⅰ (RG-Ⅰ).


Assuntos
Lotus , Rizoma , Culinária , Dureza , Pectinas , Bicarbonato de Sódio
4.
Food Chem ; 371: 131206, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34619635

RESUMO

A DIA-based quantitative proteomic strategy was used to investigate the effects of different cooking procedures (steaming and boiling) on pork meat quality. Results showed that steamed meats had higher redness, cohesion, springiness, but lower lightness, yellowness, shear force, hardness, chewiness and cooking loss than boiled meats. In total of 1608 proteins were identified and 103 proteins exhibited significant difference (fold change > 1.5, P < 0.05). These DAPs mainly involved in protein structure, metabolic enzyme, protein turnover and oxidation stress. ALDOC, PVALB, PPP1R14C, AMPD1, CRYAB and SOD1 were validated as potential indicators of color variations in cooked meat. CFL1, COL1A1, COL3A1, RTN4, NRAP, NT5C3A, and SOD1 might be potential biomarker for texture changes of cooked meats. Moreover, these validated proteins exhibited significant (P < 0.05) correlation with cooking loss and could be serve as candidate predictors for cooking loss changes of meats in different cooking procedures.


Assuntos
Carne de Porco , Proteômica , Animais , Culinária , Dureza , Carne/análise , Suínos
5.
J Nanosci Nanotechnol ; 21(6): 3325-3330, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34739789

RESUMO

High-resolution transmission electron microscopy (HRTEM), X-ray diffractometry (XRD), energy dispersive spectroscopy (EDS), and hardness testing are used to investigate the evolution of the long strip-shaped S' phase of spray-formed fine-grained Al-Cu-Mg alloy during rapid cold stamping deformation. The elongated S' phase of the extruded Al-Cu-Mg alloy is subjected to twisting, brittle fracturing, redissolution, and necking during rapid cold stamping deformation. As a result, the morphology, size, distribution, and orientation relationship with the matrix of the long strip-shaped S' phase changed significantly. The regularly distributed long strip-shaped nanoscale precipitates evolved into irregularly distributed short rod-shaped S' phases and diffusely distributed granular reprecipitates. The twist and brittle fracture of the long strip-shaped S' phase significantly increased the contact surface between the precipitated phase and the aluminum matrix, improved the interfacial distortion energy of the precipitated phase and the aluminum matrix, and promoted the redissolution of the S' phase. The supersaturation state is reached, thus resulting in reprecipitation, which then lowered the matrix free energy. The hardness of the extruded Al-Cu-Mg alloy increased from 54.2 HB to 128.1 HB during the rapid cold stamping process.


Assuntos
Ligas , Cobre , Alumínio , Dureza , Microscopia Eletrônica de Transmissão
6.
J Mech Behav Biomed Mater ; 124: 104863, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34634693

RESUMO

Biodentine is a calcium silicate/calcium carbonate/zirconium dioxide/water-based dental replacement biomaterial, significantly outperforming the stiffness and hardness properties of chemically similar construction cement pastes. We here report the first systematic micromechanical investigation of Biodentine, combining grid nanoindentation with ultrasonic testing and micromechanical modeling. Histograms of nanoindentation-probed hardness and elastic modulus, comprising more than 5700 values each, are very well represented by the superposition of three log-normal distributions (LNDs). Most of the data (74%) belong to the intermediate LND, representing highly dense calcite-reinforced hydration products with on-average more than 60GPa elastic modulus and 3GPa hardness. The remaining data refer, on the one hand, to lower density hydration products, and on the other hand, to single-micron-sized unhydrated clinker and zirconium-dioxide inclusions. Micromechanical homogenization of these three material phases delivers elastic properties of the overall cement paste material, which significantly exceed those probed by more than 300 ultrasonic tests performed in the kHz and MHz regime. This indicates the presence of micro-defects, which slightly weaken the otherwise highly optimized biomaterial system.


Assuntos
Materiais de Construção , Cimentos de Ionômeros de Vidro , Carbonato de Cálcio , Dureza , Água
7.
Med J (Ft Sam Houst Tex) ; (PB 8-21-10/11/12): 74-82, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34714926

RESUMO

INTRODUCTION: Polymerization for modern dental resin-based composites (RBCs) not only occurs immediately upon light exposure but also continues for another 24 hours, well beyond after light is terminated. However, many questions still remain about the role of polymerization kinetics in optimizing the physical properties of a new RBC type-the bulk-fill. OBJECTIVE: The aim is to study the post-cure polymerization kinetics of bulk-fill RBCs and to compare their degree of polymeric conversion (DC) and depth-of-cure (DoC) with an incremental-fill, conventional RBC. METHODS: Five representative bulk-fill RBCs [Surefil SDR+Stress Decreasing Resin Flow Plus (SDRFP), Tetric EvoCeram Bulk Fill (TECB), Filtek 1 Bulk Fill (F1B), Venus Bulk Fill (VB), and Sonicfill (SF3)] and one conventional RBC [Filtek Supreme Ultra (FSU)] were investigated. The upper surface per RBC specimen was exposed to a light curing unit (Paradigm, 3M-ESPE, irradiance=1221 ± 5 mW/cm2) for 20 seconds. The DC per RBC brand were measured at the bottom surface (specimen Ø=4 mm, thickness=3 mm and 5 mm) as a function of post-curing times using a Fourier transform infrared attenuated total reflection spectrometer. Real-time data recording for post-cure DC began immediately upon light exposure and continued at steady intervals, up to15 min, then again after 24 hours. The DoC of all six RBC brands (n=6 / group) were measured according to ISO-4049. Data were analyzed with nonlinear regression and analysis of variances (ANOVA)/Tukey (α=0.05). RESULTS: Mean DC for the six RBCs with 5 mm curing height after 24 hours were: TECB=79.5%, VB=75.7%, SDRFP=69.2%, SF3=65.8%, F1B=51.8%, and FSU=44.0%. Bulk-fill RBCs showed higher DC efficiency than the conventional RBC for both the 3 mm and 5 mm curing heights. Significant differences in DoC were found amongst the six RBC brands: VB=5.1 mm, SDRFP=4.6 mm, F1B=3.8 mm, TECB=3.5 mm, FSU=3.0 mm, and SF3=2.7 mm. CONCLUSION: DCs were more affected by specimen thickness, through which the curing light was attenuated, than RBC types. Clinician should be aware not all bulk-fill RBCs have a DoC greater than or equal to 4 mm. Also, a bulk-fill RBC that has a high DC after a post-cure time of 24 hours may not have a high DoC, which is typically measured relatively soon after light exposure.


Assuntos
Polimerização , Dureza , Cinética , Teste de Materiais
8.
J Appl Oral Sci ; 29: e20210120, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34644779

RESUMO

OBJECTIVE: Our study aims to synthesize, characterize, and determine the effects of a ChNPs suspension on human enamel after cariogenic challenge via pH-cycling. METHODOLOGY: ChNPs were synthesized by ion gelation and characterized by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering. Forty enamel blocks were divided into four groups (n=10/group): (i) ChNPs suspension; (ii) chitosan solution; (iii) 0.05% sodium fluoride (NaF) solution; and (iv) distilled water. Specimens were exposed to cariogenic challenge by cycling in demineralization solution (3 h) and then remineralized (21h) for 7 days. Before each demineralization cycle, the corresponding solutions were passively applied for 90 s. After 7 days, specimens were examined for surface roughness (Ra) and Knoop hardness (KHN) before and after the cariogenic challenge; % KHN change (variation between initial and final hardness), and surface topography by an optical profilometer. The data were analyzed by repeated-measures ANOVA, One-way ANOVA, and Tukey tests (α=0.05). RESULTS: TEM images showed small spherical particles with diameter and zeta potential values of 79.3 nm and +47.9 mV, respectively. After the challenge, all groups showed an increase in Ra and a decrease in KHN values. Optical profilometry indicated that ChNPs- and NaF-treated specimens showed uneven roughness interspersed with smooth areas and the lowest %KHN values. CONCLUSION: The ChNPs suspension was successfully synthesized and minimized human enamel demineralization after a cariogenic challenge, showing an interesting potential for use as an oral formulation for caries prevention.


Assuntos
Quitosana , Nanopartículas , Desmineralização do Dente , Cariostáticos , Esmalte Dentário , Dureza , Humanos , Fluoreto de Sódio , Desmineralização do Dente/prevenção & controle
9.
J Mech Behav Biomed Mater ; 124: 104818, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34517170

RESUMO

The high-performing biomimetic behaviors of crustaceans are the optimal results of long-time wise adaption to their living environment. One outstanding prototype is crab claw, which has the combining advantages of lightweight and high strength. To promote relevant engineering applications, it is imperative to explore its mechanical behaviors and structural characteristics. In this work, mechanical test and finite element analysis (FEA) are performed to reveal the fundamental mechanical properties and clamping behaviors of snow crab (Chionoecetes opilio) claw, respectively. A lightweight modeling method, parametric lofting modeling, for the 3D modeling of the claw is employed, which is compared with the traditional reverse engineering modeling method based on tomography image. Our results demonstrated that the hardness and modulus of the regions near the top of the claw are larger than those of the regions near of bottom of the claw. Moisture is a critical factor in controlling the tensile behavior of the claw and the wet specimens exhibit higher modulus and strength under tensile loading. Besides, The parametric lofting method is highly flexible and efficient in generating 3D geometrical model. The investigation of clamping behaviors provides not only insights into mechanical behaviors and intrinsic mechanisms but also a practical guide for their potential applications, such as designing high-performing artificial clamping muscles for clinical operations, aerospace applications, and robotics.


Assuntos
Braquiúros , Animais , Constrição , Análise de Elementos Finitos , Dureza
10.
Niger J Clin Pract ; 24(9): 1373-1379, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34531352

RESUMO

Objectives: The purpose of this study was to investigate the fracture resistance, biocompatibility, hardness, and transverse strength of non-precious metal alloy (chromium-cobalt; Cr-Co), titanium (Ti), zirconia (Zr), polymethylmethacrylate (PMMA), and polyetheretherketone (PEEK) when employed as substructure materials according to the implant supported full arch fixed prosthesis treatment concept. Materials and Methods: In total, 150 Cr-Co, Ti, Zr, PMMA, and PEEK samples (n = 30 per material) measuring 25 × 2 × 2 mm in size were produced. Of the samples, 50 (n = 10 for each material, all having dimensions of 6 × 3 mm) were subjected to biocompatibility tests. The Vickers hardness test and three-point bending test were performed; fracture resistance measurements were taken and the biocompatibility of the samples was evaluated by the XTT assay. Results: Vickers hardness was highest for Zr (p < 0.05). PEEK and PMMA had the lowest (and similar) fracture resistance values (p < 0.05). Cell proliferation on the surfaces of the materials was similar between PEEK and Zr (p > 0.05), which were the most biocompatible materials. Conclusions: Within the limitations of this study, the most favorable materials in terms of biocompatibility were found as PEEK and Zr. When biomechanical properties are evaluated, the most durable materials can be specified as Cr-Co and Zr. Also, further studies are needed to improve material stability.


Assuntos
Ligas , Titânio , Dureza , Testes de Dureza , Teste de Materiais , Próteses e Implantes
11.
Molecules ; 26(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34576926

RESUMO

Novel UV-curable polyurethane acrylate (PUA) resins were developed from rubber seed oil (RSO). Firstly, hydroxylated rubber seed oil (HRSO) was prepared via an alcoholysis reaction of RSO with glycerol, and then HRSO was reacted with isophorone diisocyanate (IPDI) and hydroxyethyl acrylate (HEA) to produce the RSO-based PUA (RSO-PUA) oligomer. FT-IR and 1H NMR spectra collectively revealed that the obtained RSO-PUA was successfully synthesized, and the calculated C=C functionality of oligomer was 2.27 per fatty acid. Subsequently, a series of UV-curable resins were prepared and their ultimate properties, as well as UV-curing kinetics, were investigated. Notably, the UV-cured materials with 40% trimethylolpropane triacrylate (TMPTA) displayed a tensile strength of 11.7 MPa, an adhesion of 2 grade, a pencil hardness of 3H, a flexibility of 2 mm, and a glass transition temperature up to 109.4 °C. Finally, the optimal resin was used for digital light processing (DLP) 3D printing. The critical exposure energy of RSO-PUA (15.20 mJ/cm2) was lower than a commercial resin. In general, this work offered a simple method to prepare woody plant oil-based high-performance PUA resins that could be applied in the 3D printing industry.


Assuntos
Acrilatos/química , Gorduras Insaturadas/química , Poliuretanos/química , Impressão Tridimensional , Géis/química , Dureza , Hidroxilação , Espectroscopia de Ressonância Magnética , Resinas Sintéticas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Termogravimetria , Raios Ultravioleta
12.
J Mech Behav Biomed Mater ; 124: 104842, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34555624

RESUMO

Indentation size effect (ISE) and R-curve behaviour of Li2O-SiO2 and Li2O-2SiO2 glass ceramics are investigated using micro-indentation and indentation-strength (IS) techniques, respectively. Vickers micro-indentations were applied on both materials at the load of 0.10-19.6 N to determine the load influence on the measured hardness. For the IS-measured fracture toughness, the load ranged from 1.96 to 19.6 N. The hardness decreased with increasing load by 20% and 18% on Li2O-SiO2 and Li2O-2SiO2 glass ceramics, respectively, indicating the ISE behaviour on both materials. The fracture toughness increased with the load by 27% and 59% on Li2O-SiO2 and Li2O-2SiO2 glass ceramics, respectively, signifying the R-curve behaviour. The ISE behaviour of both materials was analysed using the Meyer's, Hays-Kendall (HK), proportional specimen resistance (PSR), Nix-Gao (NG), modified PSR (MPSR) and elastic plastic deformation (EPD) models while the R-curve behaviour was analysed by the fractional power law. The Meyer's index of both materials was less than 2, strongly confirming the ISE existence. The HK, PSR and NG models were only suitable to determine intrinsic Vickers hardness for Li2O-2SiO2 glass ceramic while the MPSR and EPD models were successful for both materials. The fractional power law gave higher R-curve steepness for Li2O-2SiO2 than Li2O-SiO2 glass ceramics. Also, material and brittleness indices predicted, respectively, higher quasi-plasticity and better machinability for Li2O-2SiO2 than Li2O-SiO2 glass ceramics indicating superior performance in the former to the latter. Finally, this study presents a new significant insight into the micro-mechanisms of fracture tolerance behaviour of these glass ceramics which is critical to their functional performance as structural ceramics.


Assuntos
Cerâmica , Dióxido de Silício , Porcelana Dentária , Vidro , Dureza , Teste de Materiais , Propriedades de Superfície
13.
Artigo em Inglês | MEDLINE | ID: mdl-34574415

RESUMO

The main functional feature of elastomeric soft linings materials is the ability to discharge loads in the tissues of the mucosa. As a result, there are fewer injuries to the mucosa and chewing ability increases. In addition, these prostheses are more comfortable in the patient's opinion. To obtain the equal distribution of forces on the muco-bone basis and to reduce the traumatizing effect of the denture plate for patients using full dentures, soft lining materials can be used. AIM OF THE STUDY: the aim of the work was a comparative laboratory study of ten materials used for soft lining of acrylic complete dentures. METHODOLOGY: Materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and on silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast) were compared. Laboratory tests include tests of changes in Shore'a A hardness of soft lining material. The tests were conducted taking into account 90 day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. RESULTS: For most silicone materials, only small changes in hardness were found in the range of 0.7 (Ufi Gel SC) to 3.3 (Sofreliner Tough Medium) on the Shore A scale. The exception was GC Reline Soft, for which a marked increase in hardness was noted. All materials based on acrylates were characterized by successive increase in hardness over time. However, in the case of the Vertex Soft material, the increase in hardness was relatively small (5.5 ShA).


Assuntos
Reembasadores de Dentadura , Dureza , Humanos , Teste de Materiais
14.
J Mech Behav Biomed Mater ; 124: 104802, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34474322

RESUMO

Laser nitriding is one of the most promising approaches to improve wear resistance of Ti alloy surfaces and may extend the use in orthopaedic implants. In this study, three types of Ti alloys, namely alpha commercially pure Ti ("TiG2"), alpha-beta Ti-6Al-4V ("TiG5"), and beta Ti-35.5Nb-7.3Zr-5.7Ta ("ßTi"), were subjected to an open-air laser nitriding treatment. Essential elastic-plastic mechanical properties including elastic modulus, hardness, elastic energy, plasticity index, and hardness-to-elasticity ratio of the laser-treated Ti alloys were characterized using nanoindentation experiment. The results showed that the elastic modulus, hardness and elastic energy values of all Ti samples significantly increased in the nitrided layer compared to respective bare substrates for all three Ti materials. Across different Ti samples, ßTi sustained its relatively lower elastic modulus, but presented comparable hardness, elastic energy, plasticity index, as well as hardness-to-elasticity ratio in the nitrided layer compared to the other two Ti alloys. Overall, amongst three medical grade Ti alloys in this study, ßTi appeared as the most appealing candidate for joint replacement applications even solely in view of mechanical compatibility when combined with surface laser nitriding. Nevertheless, laser nitriding treatment in this study tended to cause a residual compressive stress on all Ti alloys as displayed by cracks developed in the nitrided layer and analyzed on ßTi by X-ray diffraction (XRD) and further nanoindentation tests.


Assuntos
Ligas , Ortopedia , Materiais Biocompatíveis , Dureza , Lasers , Teste de Materiais , Plásticos , Propriedades de Superfície , Titânio
15.
J Mech Behav Biomed Mater ; 124: 104810, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34500355

RESUMO

OBJECTIVE: The aim of the study was to determine the effects of ultra-fast (3 s) light-curing on the viscoelastic behaviour at clinically relevant frequencies, and cell toxicity, in a resin-based composite (RBC) with reversible addition-fragmentation-chain transfer (RAFT) mediated polymerization. METHODS: Three different protocols were used to cure cylindrical samples (height = 4 mm, Ï´ = 5 mm), including ultra-fast (3s) cure with high radiant emittance, 10 s and 20 s cure with moderate radiant emittance. The properties of the light curing device were evaluated in all curing protocols by spectrophotometry up to an exposure distance of 10 mm. The light transmission through the samples was determined in real-time with the same spectrophotometer. Absorbance was calculated as a function of wavelength. The quasi-static (indentation hardness/HIT, indentation modulus/EIT) and viscoelastic (storage modulus/E', loss modulus/E″, loss factor/tan Î´) material behavior was determined in an instrumented indentation test with a DMA (Dynamic Mechanical Analysis) module for 10 frequencies (0.5-5 Hz) by profiling the center of the samples in 330 µm steps from top to bottom. Cellular toxicity on human gingival fibroblast (HGF-1) was assessed using a WST-1 colorimetric assay after incubation time of up to 3 months. One and multiple-way analysis of variance (ANOVA) with Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05) were applied. RESULTS: The irradiance transmitted through a 4 mm high sample was less than 7% of the incident irradiance, and the absorbance was similar for all curing protocols, showing a decrease with wavelength. Similar quasi-static and viscoelastic parameters were observed regardless of the curing protocol. HIT increased slightly and EIT, E', E″ and tan Î´ decreased with frequency. Occasionally, slightly higher confidence intervals were observed for the ultra-fast curing group, which were related to a potential accumulation of stress. The curing protocol had no effect on cell viability (p = 0.326) but the eluate age (p < 0.001, ηP2 = 0.879) did. None of the groups showed cell toxicity at any point in time with respect to the corresponding negative control. CONCLUSIONS: The ultra-fast curing with high irradiance induced no cell toxicity and an equivalent viscoelastic behavior as with conventional curing protocols in a RAFT-modified RBC.


Assuntos
Resinas Compostas , Luzes de Cura Dentária , Resinas Compostas/toxicidade , Materiais Dentários , Dureza , Humanos , Teste de Materiais , Polimerização , Propriedades de Superfície
16.
Poult Sci ; 100(10): 101395, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34455310

RESUMO

Drying temperature (DT) of corn can influence its nutritional quality, but whether this is influenced by endosperm hardness is not clear. Two parallel experiments were conducted to investigate the effects of 2 yellow dent corn hybrids with average and hard kernel hardness, dried at 3 temperatures (35, 80, and 120°C), and 2 supplementation levels of an exogenous amylase (0, 133 g/ton of feed) on live performance, starch and protein digestibility, and energy utilization of Ross 708 male broilers. Twelve dietary treatments consisting of a 2 × 3 × 2 factorial arrangement were evaluated using 3-way ANOVA in a randomized complete block design. In Experiment 1, a total of 1,920 male-chicks were randomly allocated to 96 floor pens, whereas 480 day-old chicks were distributed among 96 cages for Experiment 2. At 40 d, interaction effects (P < 0.05) were detected on BWG, FCR, and flock uniformity. Supplementation with exogenous amylase resulted in heavier broilers, better FCR and flock uniformity, only in the diets based on corn dried at 35°C. Additionally, interaction effects were observed on FCR due to kernel hardness and DT (P < 0.01), kernel hardness and amylase supplementation (P < 0.001), and DT and amylase supplementation (P < 0.05). Exogenous amylase addition to the diets based on corn with an average hardness improved FCR up to 2 points (1.49 vs. 1.51 g:g) whereas there was no effect of amylase on FCR of broilers fed diets based on corn with hard endosperm. Total tract retention of starch was increased (P < 0.05) in broilers fed diets based on corn with average kernel hardness compared to hard kernel. Corn dried at 80 and 120°C had up to 1.21% points less starch total tract retention than the one dried at 35°C. Supplementing alpha-amylase resulted in beneficial effects for broiler live performance, energy utilization, and starch total tract digestibility results. Treatment effects on starch characteristics were explored. Corn endosperm hardness, DT and exogenous amylase can influence the live performance of broilers. However, these factors are not independent and so must be manipulated strategically to improve broiler performance.


Assuntos
Galinhas , Zea mays , Amilases , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Digestão , Dureza , Nutrientes , Temperatura
18.
Acta Biomater ; 134: 531-545, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34428562

RESUMO

The relationship between diet, bite performance, and tooth structure is a topic of common interest for ecologists, biologists, materials scientists, and engineers. The highly specialized group of biters found in Serrasalmidae offers a unique opportunity to explore their functional diversity. Surprisingly, the piranha, whose teeth have a predominantly cutting function and whose main diet is soft flesh, is capable of exerting a greater bite force than a similarly sized pacu, who feeds on a hard durophagous diet. Herein, we expand our understanding of diet specialization in the Serrasalmidae family by investigating the influence of elemental composition and hierarchical structure on the local mechanical properties, stress distribution, and deformation mechanics of teeth from piranha (Pygocentrus nattereri) and pacu (Colossoma macropomum). Microscopic and spectroscopic analyses combined with nanoindentation and finite element simulations are used to probe the hierarchical features to uncover the structure-property relationships in piranha and pacu teeth. We show that the pacu teeth support a durophagous diet through its broad cusped-shaped teeth, thicker-irregular enameloid, interlocking interface of the dentin-enameloid junction, and increased hardness of the cuticle layer due to the larger concentrations of iron present. Comparatively, the piranha teeth are well suited for piercing due to their conical-shape which we report as having the greatest stiffness at the tip and evenly distributed enameloid. STATEMENT OF SIGNIFICANCE: The hierarchical structure and local mechanical properties of the piranha and pacu teeth are characterized and related to their feeding habits. Finite element models of the anterior teeth are generated to map local stress distribution under compressive loading. Bioinspired designs from the DEJ interface are developed and 3D printed. The pacu teeth are hierarchically structured and have local mechanical properties more suitable to a durophagous diet than the piranha. The findings here can provide insight into the design and fabrication of layered materials with suture interfaces for applications that require compressive loading conditions.


Assuntos
Caraciformes , Dente , Animais , Força de Mordida , Dieta , Dureza , Estresse Mecânico
19.
Dent Mater ; 37(10): 1584-1591, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34417024

RESUMO

OBJECTIVE: This study is focused on testing experimental rapid prototyping materials for occlusal splints made from Urethandimethacrylate (UDMA) and Urethanmethacrylate (UMA). METHODS: Materials were mixed from UDMA and UMA in ratios of 1.0:0.0, 0.75:0.25, 0.5:0.5, 0.25:0.75 and 0.0:1.0. Specimens were printed using digital light processing (DLP). After post-processing, the specimens underwent testing on flexural strength, modulus of elasticity, hardness, wear behavior, surface roughness, gloss and color stability. All tests were performed after 24 h (baseline) and 10 days of water storage (aging). Splints underwent cyclic pull-off and insertion testing, which was alongside simulated using finite element analysis. RESULTS: The mechanical properties were significantly influenced by changes in the UDMA:UMA ratio. Statistical analysis revealed that increased amounts of UMA correlated with a decrease in flexural strength (92.0 to 30.7 MPa), modulus of elasticity (2.4 to 0.6 GPa), hardness (155.1 to 102.0 N/mm2) and wear resistance (-1394.9 to -1742.1 µm). Materials with higher amounts of UMA were also more likely to be influenced by water storage. Specimens with 75% and 100% UMA content were partly not analyzable due to soft consistency. Optical properties showed only minor influence from UMA content and aging. Differences in surface roughness (3.9 to 2.4 µm) and color stability were insignificant. Gloss was partly influenced by the UDMA:UMA ratio and water storage. Mean survival rates for cyclic pull-off and insertion testing ranged from 2537 to 23,857 cycles. A correlation between the amount of UMA and survival rates was observed. SIGNIFICANCE: The addition of up to 25% UMA showed promising results, complying with clinical standards and delivering acceptable results in the cyclic pull-off and insertion test. Further investigation on increments between 0 and 25% UMA could help to find an optimum.


Assuntos
Resinas Compostas , Resistência à Flexão , Elasticidade , Dureza , Teste de Materiais , Propriedades de Superfície
20.
Int J Mol Sci ; 22(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34445798

RESUMO

The bacterium Legionella pneumophila is still one of the probable causes of waterborne diseases, causing serious respiratory illnesses. In the aquatic systems, L. pneumophila exists inside free-living amoebae or can form biofilms. Currently developed disinfection methods are not sufficient for complete eradication of L. pneumophila biofilms in water systems of interest. Photodynamic inactivation (PDI) is a method that results in an antimicrobial effect by using a combination of light and a photosensitizer (PS). In this work, the effect of PDI in waters of natural origin and of different hardness, as a treatment against L. pneumophila biofilm, was investigated. Three cationic tripyridylporphyrins, which were previously described as efficient agents against L. pneumophila alone, were used as PSs. We studied how differences in water hardness affect the PSs' stability, the production of singlet oxygen, and the PDI activity on L. pneumophila adhesion and biofilm formation and in biofilm destruction. Amphiphilic porphyrin showed a stronger tendency for aggregation in hard and soft water, but its production of singlet oxygen was higher in comparison to tri- and tetracationic hydrophilic porphyrins that were stable in all water samples. All three studied porphyrins were shown to be effective as PDI agents against the adhesion of the L. pneumophila to polystyrene, against biofilm formation, and in the destruction of the formed biofilm, in their micromolar concentrations. However, a higher number of dissolved ions, i.e., water hardness, generally reduced somewhat the PDI activity of all the porphyrins at all tested biofilm growth stages.


Assuntos
Biofilmes/efeitos dos fármacos , Cátions/farmacologia , Dureza/efeitos dos fármacos , Legionella pneumophila/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Água/química , Amoeba/microbiologia , Oxigênio Singlete/farmacologia , Microbiologia da Água
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