Influence of ultimate pH on biochemistry and quality of Longissimus lumborum steaks from Nellore bulls during ageing

Ultimate pH (pH_u) is an indicator that influences post-mortem meat quality. We studied physiological and biochemical changes of steaks obtained from Nellore bulls (Bos indicus) during post-mortem ageing. To this, Longissimus lumborum (LL) muscles were classified into three groups: Normal-pH_u (≤5.79), Intermediate-pH_u (5.80–6.29) and High-pH_u (≥6.30) groups, portioned into steaks, vacuum packaged and matured at 2 °C for 0, 7, 14, 21 and 28 days. High-pH_u steaks exhibited impaired colour stability and were darker compared to the other groups. High- and Normal-pH_u steaks showed improved tenderness and myofibrillar fragmentation linked to proteolysis. Intermediate-pH_u steaks were associated with a lower meat tenderness and decreased collagen solubility. High-pH_u steaks retained a high pH during ageing and increased water-holding capacity. These findings provide evidence that highlight pH_u as a strategy for the classification of pH_u-dependent beef quality from Nellore bulls that can be adopted by the Brazilian meat industry.     

How the geometry of cities determines urban scaling laws

Urban scaling laws relate socio-economic, behavioural and physical variables to the population size of cities. They allow for a new paradigm of city planning and for an understanding of urban resilience and economics. The emergence of these power-law relations is still unclear. Improving our understanding of their origin will help us to better apply them in practical applications and further research their properties. In this work, we derive the basic exponents for spatially distributed variables from fundamental fractal geometric relations in cities. Sub-linear scaling arises as the ratio of the fractal dimension of the road network and of the distribution of the population embedded in three dimensions. Super-linear scaling emerges from human interactions that are constrained by the geometry of a city. We demonstrate the validity of the framework with data from 4750 European cities. We make several testable predictions, including the relation of average height of cities and population size, and the existence of a critical density above which growth changes from horizontal densification to three-dimensional growth.     

On the stability of the V5B6-phase

The currently assessed V–B phase diagram indicates a peritectoid formation at 1727 °C (V₃B₄+VBV₅B₆) for the V₅B₆ boride. The observation of this phase in several as-cast V–B alloys has lead us to a systematic evaluation of its stability, specially its possible formation from the liquid. In this work, V–B alloys (52–56 at.% B range) were produced through arc melting and heat-treated under high vacuum at 2000 °C for 2 h. The materials in both as-cast and heat-treated conditions were characterized through scanning electron microscopy (SEM) (backscattered electron (BSE) images) and X-ray diffraction (XRD). The features observed in the as-cast samples allowed us to conclude that this phase should be formed from the liquid through the L+V₃B₄V₅B₆ peritectic reaction. In spite of not reaching equilibrium condition during heat-treating, the results from the characterization of heat-treated samples have indicated the stability of the V₅B₆-phase at 2000 °C, in disagreement with the currently accepted V–B phase diagram.     

Analysis of the interfacial micromorphology of adhesive systems in cavities prepared with Er,Cr:YSGG, Er:YAG laser and bur

The purpose of this in vitro study was to evaluate the interaction pattern of adhesive systems on laser and bur cavities. Cavities were prepared according to the following groups (n=9): (G1) conventional diamond bur (No. 1013); (G2) Er:YAG laser (250 mJ, 4 Hz, 80.6 J/cm2); (G3) Er,Cr:YSGG laser (3.5 W, 20 Hz, 61.7 J/cm2). After cavity preparation, specimens were divided into three subgroups differing the adhesive systems used (n=3): (GA) AdheSE; (GB) Clearfil standard error (SE) Bond; (GC) Single Bond. After insertion of a micro-hybrid composite resin, the specimens were sectioned across the bonded surface dividing the teeth into two halves, which were prepared for SEM analysis. Cavities prepared with laser appeared to be more irregular than the bur cavities. Different patterns of gap formation and resin tags could be observed, showing the differences, advantages, and disadvantages of both types of cavities. Under the settings of the present study, resin tags were more pronounced in lased dentin than bur prepared dentin independently of the bonding systems used. On the other hand gap formation between dentin and resin in laser prepared cavities was observed suggesting collagen alteration.     

Surface treatment of glass fiber and carbon fiber posts: SEM characterization

Morphology, etching patterns, surface modification, and characterization of 2 different fiber posts: Gfp, Glass fiber post; and Cfp, carbon fiber were investigated by SEM analysis, after different surface treatments. Thirty fiber posts, being 15 Gfp and 15 Cfp were divided into a 5 surface treatments (n = 3): C-alcohol 70% (control); HF 4%-immersion in 4% hydrofluoric acid for 1min; H(3) PO(4) 37%-immersion in 37% phosphoric acid for 30s; H(2) O(2) 10%-immersion in 10% hydrogen peroxide for 20 min; H(2) O(2) 24%-immersion in 24% hydrogen peroxide for 10 min. Morphology, etching patterns, surface modification and surface characterization were acessed by SEM analysis. SEM evaluation revealed that the post surface morphology was modified following all treatment when compared with a control group, for both type of reinforced posts. HF seems to penetrate around the fibers of Gfp and promoted surface alterations. The Cfp surface seems to be inert to treatment with HF 4%. Dissolution of epoxy resin and exposure of the superficial fiber was observed in both post groups, regardless the type of reinforcing fiber, H(2) O(2) in both concentrations. Relative smooth surface area was produced by H(3) PO(4) 37% treatment, but with similar features to untreated group. Surface treatment of fiber post is a determinant factor on micromechanical entanglement to resin composite core. Post treatment with hydrogen peroxide resulted strength of carbon and glass/epoxy resin fiber posts to resin composite core.     

The photoreceptive cells of the pineal gland in adult zebrafish (Danio rerio)

The zebrafish pineal gland plays a fundamental role in the regulation of the circadian rhythm through the melatonin secretion. The pinealocytes, also called photoreceptive cells, are considered the morphofunctional unit of pineal gland. In literature, the anatomical features, the cellular characteristics, and the pinealocytes morphology of zebrafish pineal gland have not been previously described in detail. Therefore, this study was undertaken to analyze the structure and ultrastructure, as well as the immunohistochemical profile of the zebrafish pineal gland with particular reference to the pinealocytes. Here, we demonstrated, using RT-PCR, immunohistochemistry and transmission electron microscopy, the expression of the mRNA for rhodopsin in the pineal gland of zebrafish, as well as its cellular localization exclusively in the pinealocytes of adult zebrafish. Moreover, the ultrastructural observations demonstrated that the pinealocytes were constituted by an outer segment with numerous lamellar membranes, an inner segment with many mitochondria, and a basal pole with the synapses. Our results taken together demonstrated a central role of zebrafish pinealocytes in the control of pineal gland functions.     

Effects of tip-sample forces and humidity on the imaging of DNA with a scanning force microscope

We have investigated the effects of tip-sample forces and relative humidity when using a scanning force microscope (SFM) to image DNA molecules adsorbed on fresh mica. As the force between the tip and the sample increases, the apparent height of the DNA molecules decreases. After being imaged with high forces, the DNA molecules recover partially in their apparent height, indicating that a plastic deformation of the DNA has been induced by the scanning tip. At low humidities, DNA molecules can be imaged with a force up to 150 nN during the scanning without obvious damages. At higher humidities, however, the DNA molecules can be dissected or swept away by the tip even at a tip-sample force of 30 nN. The net force between the tip and the molecules is the vector sum of several forces, the dominant components of which are the elastic force due to the cantilever bending and the capillary force resulting from the water meniscus formed between the tip and the sample surface. When the relative humidity of the imaging environment is increased, the capillary force becomes stronger.     

Interfaces in MoSi2-SiC In Situ composites synthesized by melt processing

Interfaces between the primary β-SiC and the surrounding MoSi₂ matrix in melt-synthesized in situ composites have been investigated, with emphasis on the chemistry and crystallographic relationships developed during solidification. Primary SiC growth occurs with {002} and {111} facets, both of which are found to template the subsequent nucleation and epitaxial growth of the MoSi₂ matrix. Eight independent orientation relationships (ORs) were identified, involving the following combinations of planes: $$\begin{gathered} \left\{ {002} \right\}_{Sic} \parallel \left( {001} \right)_{MoSi_2 } \left( {3 rotational variants} \right), or \{ 101)_{MoSi_2 } \hfill \\ \left\{ {111} \right\}_{Sic} \parallel (001)_{MoSi_2 } , or \{ 100)_{MoSi_2 } \left( {2 rotational variants} \right),or \{ 101)_{MoSi_2 } \hfill \\ \end{gathered} $$ The interfacial relationships were rationalized using coincident site lattice arguments as well as energetic simulations based on the Grey-Bohr algorithm. The latter analysis suggests that the multiplicity of relationships arises from local effects associated with the size and shape of the adsorbate layers preceding the formation of the MoSi₂ nuclei. An amorphous carbon layer, 2- to 5-nm thick, was detected at all interfaces and some of the matrix grain boundaries. This interphase is believed to evolve by solid-state precipitation of C during postsolidification cooling and is, in principle, metastable. The C interphase enables easy debonding and thus may have important implications for the mechanical performance of materials involving SiC/MoSi₂ constituents.     

A Survey of User-Centred Approaches for Smart Home Transfer Learning and New User Home Automation Adaptation

Recent smart home applications enhance the quality of people’s home experiences by detecting their daily activities and providing them services that make their daily life more comfortable and safe. Human activity recognition is one of the fundamental tasks that a smart home should accomplish. However, there are still several challenges for such recognition in smart homes, with the target home adaptation process being one of the most critical, since new home environments do not have sufficient data to initiate the necessary activity recognition process. The transfer learning approach is considered the solution to this challenge, due to its ability to improve the adaptation process. This paper endeavours to provide a concrete review of user-centred smart homes along with the recent advancements in transfer learning for activity recognition. Furthermore, the paper proposes an integrated, personalised system that is able to create a dataset for target homes using both survey and transfer learning approaches, providing a personalised dataset based on user preferences and feedback.