Lower Shear Force Research Articles

The Assessment of the Possibility of Using Yellow Mealworm Powder in Chicken and Pork Pâté Production

Meat delicatessen products, including pâtés, are important for consumers’ daily diets. However, due to the complex recipe composition, pâtés can also contain allergens such as gluten. Simultaneously, powdered edible insects are increasingly used to reformulate food products. Therefore, the paper aimed to investigate the feasibility of replacing wheat flour (total content: 9% w/w) with yellow mealworm powder (3:0, 2:1, 1:2, and 0:3) in chicken and pork pâtés and determine its effect on their quality properties. The rheological properties of pâté batter, as well as texture, color parameters, and microbiological and sensory characteristics of pâtés, were assessed. All prepared pâté batters were identified as weak gels. Furthermore, all the examined pâtés met the microbiological quality requirements. Adding yellow mealworm powder to the formulation weakened the pâté structure, resulting in significantly lower shear force and increased spreadability. In addition, it led to a darker and more gray color of the pâtés. It may be seen as indicating no preservatives or as resembling a typical pork pâté. It has been demonstrated that the complete replacement of wheat flour with insect powder significantly reduced the sensory quality of chicken and pork pâtés.

Meat tenderness in Australian lamb: Data editing, environmental variation and their effects in genetic parameter estimation

Breeding for meat quality increases the value of lambs and requires reliable genetic parameters to achieve balanced genetic progress. Meat tenderness, accomplished by selecting for lower shear force, is an important eating quality trait because of its relationship with consumer satisfaction. Factors influencing shear force, include the pH and temperature decline post-mortem which can contribute towards higher shear force values and increased variation across contemporary groups. This study explored if genetic parameters for shear force change when post slaughter covariates and heterogeneous variance are corrected for, using data from 32,223 animals from different sheep breeds. Results showed that removing extreme individuals and contemporary groups with high mean shear force values reduced residual variance, followed by a smaller reduction in additive genetic variance and little effect on heritability. Results show that edited data performed better at predicting progeny performance and reduced potential bias introduced in the genetic evaluation due to data quality. The effect of including post-slaughter covariates in the genetic analysis was tested by estimating different model predictability through regression of estimated breeding values against offspring performance, showing that the model including hot carcass weight performed better followed by the one including both carcass weight and C-site fat depth. Our results highlight that historic and current in-plant recording practices do not provide the capacity to account for non-genetic factors associated with abattoir environment that might be impacting the ability to accurately calculate shear force breeding values. In that sense, genetic evaluation can be improved by applying more rigorous data editing.

How does moderate upper limb activity modify sitting forces for able-bodied persons and wheelchair users?

Introduction Most people with a spinal cord injury are concerned by pressure injuries (PrI). Since dynamic activities may involve distributions of forces over time that are different from static and given the significant impact of PrIs on healthcare costs, it is, important to study these sitting forces. We aim to investigate sitting forces (overall normal, shear forces and Peak Pressure Index (PPI)) assessed in both able-bodied and wheelchair users (WCU) under static and dynamic conditions. Our hypothesis is that wheelchair sitting forces encountered by able-bodied participants are significantly different from those of WCUs. Material and Methods An experimental seat and a pressure mapping system were used to investigate forces in two different populations, 102 able-bodied and 15 WCUs, in static conditions and during synchronised hand-cycling. The analysis includes statistical comparisons of the sitting conditions (static/dynamic) and of the populations (able-bodied/WCUs). Results and discussion Significant differences in normal forces and PPI were observed between able-bodied and WCUs; conversely, differences in shear forces were non-significant. This suggests that contrary to shear forces, no conclusion on normal forces drawn from trials with healthy participants can directly be applied to WCUs. Secondly, the present results indicate significant reduced averaged: normal force, PPI, and shear forces for able-bodied performing a dynamic activity compared to static sitting. WCUs experienced non-significant lower averaged normal force and PPI but significant lower averaged shear forces. Conclusion While the present results seem to indicate lower forces for able-bodied performing a dynamic activity compared to static sitting, due to reduced averaged forces, this conclusion is less clear-cut for WCUs.

Stable low friction of sp2 nanocrystallited carbon films in different vacuum pressures

This study reported the stable low friction of sp2 nanocrystallited carbon films in vacuum environment. Carbon film with larger sp2 nanocrystallites size demonstrated consistently low friction in different vacuum pressures. The lowest friction coefficient arrived 0.018 at 10–6 Pa with a long stable sliding cycles. The mechanisms were ascribed to the stable contact interfaces formed by the rapidly transferred sp2 nanocrystallites and the oxidation passivation layer. The low shear force at the nanocrystallited interface reduced the friction and the oxidation passivation promised the stabilization of interface. Carbon film with smaller sp2 nanocrystallite size only achieved low friction of 0.023 at 10–6 Pa, and the film exhibited high friction at 10-1∼10-3 Pa due to the insufficient passivation and large dangling bonds. As pure carbon film, sp2 nanocrystallited carbon films offer broadly application possibilities for vacuum micro-/nano- devices.

Organic rearing of non-castrated male pigs: welfare indicators, carcass traits, pork quality and boar taint in Duroc and Pietrain crossbreds

The main principles of organic farming as presented by the European organisation for organic food and farming are health, ecology, fairness and care, but the intrinsic quality of products is also important for consumers. Pig genotype was tested as a lever to improve animal welfare and pork quality (meat tenderness, processing ability) of organic, non-castrated males while controlling the risk for boar taint. Non-castrated Large White × Duroc (D, n = 47) or Large White × Pietrain NN (P, n = 34) males were involved in two batches, each including one group of pigs per genotype. Each group was reared in a pen from the same building on deep straw bedding (1.3 m2/pig), with a feeding zone (0.2 m2/pig) and an outdoor area (1.0 m2/pig), from 28 kg BW until slaughter at ca. 125 kg BW. All pigs received ad libitum the same growing and finishing diets, and hay. Overall, health and welfare indicators showed few problems, but the proportions of pigs with skin scratches, and tail lesions at the end of the finishing period, were lower in D than in P pigs (P < 0.05). Growth rate and final BW did not differ between genotypes. The D pigs had lower carcass lean meat content (P < 0.001) and relative proportions of ham and loin (P ≤ 0.01), and higher proportions of belly and backfat (P ≤ 0.001) than P pigs. Compared to P, loin (Longissimus muscle) of D pigs was less light and exudative and had higher chroma (P < 0.05), but pH 24 h and glycolytic potential did not differ. Loin meat of D pigs had higher intramuscular fat content (P < 0.001) and tended to have a lower shear force (P = 0.09), but cooking loss did not differ. In the ham muscles, D pigs had higher chroma than P pigs in the Gluteus medius, whereas pH 24 h did not differ in the Gluteus medius and Semimembranosus. D pigs had higher backfat concentrations of androstenone (P < 0.001), and skatole and indole (P < 0.05) than P pigs, suggesting a higher risk of rejection by consumers due to boar taint. However, only one D carcass was detected as tainted by human nose test. Altogether, organic farming of non-castrated Duroc crossbred males appears to be favourable for animal welfare, technological and several sensory pork properties provided that the risk of undesirable odours is limited through management practices.

Microbiology of human spaceflight: microbial responses to mechanical forces that impact health and habitat sustainability.

SUMMARYUnderstanding the dynamic adaptive plasticity of microorganisms has been advanced by studying their responses to extreme environments. Spaceflight research platforms provide a unique opportunity to study microbial characteristics in new extreme adaptational modes, including sustained exposure to reduced forces of gravity and associated low fluid shear force conditions. Under these conditions, unexpected microbial responses occur, including alterations in virulence, antibiotic and stress resistance, biofilm formation, metabolism, motility, and gene expression, which are not observed using conventional experimental approaches. Here, we review biological and physical mechanisms that regulate microbial responses to spaceflight and spaceflight analog environments from both the microbe and host-microbe perspective that are relevant to human health and habitat sustainability. We highlight instrumentation and technology used in spaceflight microbiology experiments, their limitations, and advances necessary to enable next-generation research. As spaceflight experiments are relatively rare, we discuss ground-based analogs that mimic aspects of microbial responses to reduced gravity in spaceflight, including those that reduce mechanical forces of fluid flow over cell surfaces which also simulate conditions encountered by microorganisms during their terrestrial lifecycles. As spaceflight mission durations increase with traditional astronauts and commercial space programs send civilian crews with underlying health conditions, microorganisms will continue to play increasingly critical roles in health and habitat sustainability, thus defining a new dimension of occupational health. The ability of microorganisms to adapt, survive, and evolve in the spaceflight environment is important for future human space endeavors and provides opportunities for innovative biological and technological advances to benefit life on Earth.

Amine-Based Chemistries for the Megasonic Removal of Alumina Nanoparticles from Oxidized Silicon Carbide

Increasing demand for improved Integrated Circuit (IC) technology has propelled the advancement from silicon as a semiconductor material to Wide Band Gap (WBG) materials (i.e., Silicon carbide (SiC), Gallium nitride (GaN)) due to their intrinsic properties (i.e., increased thermal stability, wear resistance, etc.). While these traits make WBGs ideal semiconductor materials, the Chemical Mechanical Planarization (CMP) process becomes difficult as these surfaces are more chemically inactive. To overcome this, the CMP process has shifted to incorporate more aggressive chemical and mechanical conditions (i.e., highly oxidative chemistries, increased shear force, etc.) to reach desired material removal rates (MRR). Traditional post-CMP (pCMP) cleaning processes combine high shear forces via a Polyvinyl Alcohol (PVA) brush with oxidative cleaning chemistries to remove CMP residue. This, however, results in secondary defect generation (i.e., scratches, pitting, brush debris) on the substrate surface. A low-shear force, non-contact cleaning process via megasonic energy is one way to combat secondary defect generation. The megasonic energy serves a dual function of reducing the substrate’s surface boundary layer, which allows for enhanced surface interaction with various cleaning solutions while also generating reactive oxygen species (ROS) that activate the chemistry. This work focuses on amine-based cleaning chemistries for oxidized SiC substrates. The introduction of the amine leads to a reduction of the oxidized surface, allowing for a weakened residue-substrate bond for an improved particle removal efficiency (PRE). Initial results have shown that amine-based standard clean 1 (SC-1) produced comparable results to previously utilized cleaning chemistries (i.e., Supramolecular chemistries), with a PRE of 11.4%. The PRE of SC-1 increases significantly in proportion to sonication power, with the highest PREs ranging between 90% to 96%. This work will provide insight into oxidized SiC surface behavior by incorporating other amine-based cleaning chemistries.

Carcass and Meat Characteristics of Cull Heifers from Different Genetic Groups Fed Diets with Different Sources of Nonprotein Nitrogen in Confinement.

The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN-(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)-in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles.

Development and Characterization of Hybrid Burgers Made from Pork and Multi-Ingredient Plant Mixtures and Protected with Lactic Acid Bacteria

Hybrid (meat–plant) products can be a sustainable response to the increased interest in flexitarianism. Their development requires designing appropriate composition and functional properties and ensuring microbiological safety. This study aimed to determine the influence of using various multi-ingredient plant mixtures and pork in different proportions and two recipe variants on the characteristics of baked burgers. Additionally, the impact of lactic acid bacteria (LAB) application on the microbiological quality of raw hybrid/plant burgers was assessed. All products were analyzed in terms of basic chemical composition (NIR spectroscopy) and physicochemical and textural properties (instrumental methods). The raw plant and hybrid burgers met the microbiological requirements. The baked burgers did not significantly differ in terms of their chemical composition, except for the fiber found in plant/hybrid samples. Moreover, the reformulation of burgers had no effect on their cooking yield or water activity. As the content of plant parts increased, the baked burgers were darker (lower L*) and had a more tender texture (lower shear force and penetration force). Overall, the multi-ingredient plant mixtures showed great potential in the development of high-quality hybrid burgers. However, the texture formed can, importantly, determine final consumer acceptance. Therefore, research should be continued, especially in terms of comprehensive textural and sensory analyses.

Flow shear force destabilizes carotid plaques by affecting CHOP and GRP78 proteins

BackgroundVarious factors, including blood, inflammatory, infectious, and immune factors, can cause ischemic stroke. However, the primary cause is often the instability of cervical arteriosclerosis plaque. It is estimated that 18-25% of ischemic strokes are caused by the rupture of carotid plaque.1 Plaque stability is crucial in determining patient prognosis. Developing a highly accurate, non-invasive, or minimally invasive technique to assess carotid plaque stability is crucial for diagnosing and treating stroke.Previous research by our group has demonstrated that the expression levels of CHOP (C/EBP homologous protein) and GRP78 (glucose-regulated protein 78) are correlated with the stability of atherosclerotic plaques.2 ObjectThis research assesses changes in GRP78 and CHOP expressions in human umbilical vein endothelial cells(HUVEC) following experiments within the hemodynamic influencing factors test system. Additionally, it includes conducting an empirical study on the impact of blood flow shear force on the stability of human carotid atherosclerotic plaques. The objective is to explore the implications of blood flow shear force on the stability of carotid atherosclerotic plaques. MethodThe hemodynamic influencing factors test bench system was configured with low (Group A, 4 dyns/cm²), medium (Group B, 8 dyns/cm²), and high shear force groups (Group C, 12 dyns/cm²). Relative expression levels of GRP78 and CHOP proteins in human umbilical vein endothelial cells were measured using Western blot analysis, and quantitative analysis of GRP78 and CHOP mRNA was conducted using RT-qPCR. Meanwhile, plaques from 60 carotid artery patients, retrieved via Carotid Endarterectomy (CEA), were classified into stable (S) and unstable (U) groups based on pathological criteria. Shear force at the carotid bifurcation was measured preoperatively using ultrasound. Western blot and RT-qPCR were used to analyze the relative expression levels of GRP78 and CHOP proteins and mRNA, respectively, in the plaque specimens from both groups. ResultExpression levels of GRP78, CHOP proteins, and their mRNAs were assessed in groups A, B, and C via Western blot and RT-qPCR. Results showed that in the low-shear group, all markers were elevated in group A compared to groups B and C. Statistical analysis revealed significantly lower shear forces at the carotid bifurcation in group U compared to group S. In group U plaques, GRP78 and CHOP expressions were significantly higher in group U than in group S. ConclusionBlood flow shear forces variably affect the expression of GRP78 and CHOP proteins, as well as their mRNA levels, in vascular endothelial cells. The lower the shear force and fluid flow rate, the higher the expression of GRP78 and CHOP, potentially leading to endoplasmic reticulum stress(ERS), which may destabilize the plaque.

Development of semi-dried goat meat jerky using tenderizers considering the preferences of the elderly.

Elderly people avoid eating red meat and dried meat product due to its texture and stiffness; they deprive them of rich sources of nutrients. In addition, food-related diseases are exponentially increasing due to using synthetic additives in food products. Therefore, this research aimed to develop semi-dried goat meat jerky considering geriatric preferences by using natural tenderizers and nitrate. Four treatments were formulated negative control (NC [synthetic nitrite without tenderizers]), positive control (PC [Swiss chard without tenderizers]), T1 (Swiss chard with pineapple powder), and T2 (Swiss chard with pineapple and tomato powder). T1 and T2 had higher processing yield, and rehydration capacity compared with NC and PC. The fat content of T1 and T2 was lower than the control groups. Moisture was significantly higher in T1, NC, and T2 than in PC (p < 0.05). T2 showed the lowest water activity (0.87), lowest shear force (4.82 kgf), and lowest total plate count (TPC). The lowest pH and thiobarbituric acid reactive substances (TBARS) were observed in T1 and T2. T1 showed the lowest lightness and the maximum redness (p < 0.05) while PC showed the lowest yellowness. During the storage period, moisture and pH decreased, and TPC and TBARS significantly increased whereas water activity is stable regardless of the treatment. The results of the myofibrillar fragmentation index (MFI) and sodium dodecyl sulfate-polyacrylamide gel revealed that T1 and T2 more effectively converted protein to polypeptides. In addition, tenderizers positively affected thrombogenicity, atherogenicity, and hypocholesterolemic/hypercholesterolemic indices. T2 observed the highest overall sensory acceptance by reducing goaty flavor. Overall, jerky treated with tenderizers is easily chewable and digestible for the elderly due to its tenderness and essential fatty acids that would be senior-friendly food.

Transcriptome analysis reveals the effects of Schizochytrium sp. on the meat quality attributes of Tan lambs

Schizochytrium sp., a feed additive, positively affects the quality of animal meat. In this study, the molecular mechanisms through which dietary Schizochytrium sp. affects the meat quality characteristics of Tan lambs were investigated using transcriptomic techniques. The findings demonstrate that the lambs supplemented with Schizochytrium sp. had a larger loin eye area and a higher average daily gain and intramuscular fat content (P < 0.05). They also had lower drip loss (at 24 and 48 h) and shear force (P < 0.05). Further, 745 genes were differentially expressed between lambs supplemented with Schizochytrium and the control group. Moreover, KEGG pathway analysis showed that the ECM-receptor interaction pathway, which is related to muscle generation and intramuscular fat deposition, was significantly enriched in the lambs administered a diet containing Schizochytrium sp. Herein, we identified some pivotal genes linked to muscular system development and lipid metabolism. Thus, using Schizochytrium sp. may boost the meat quality of Tan lambs by modifying the expression of genes related to hub pathways. The results supply a new basis to determine the molecular mechanisms through which Schizochytrium sp. supplementation regulates the meat quality characteristics of sheep.

Engineering EPS in Halomonas bluephagenesis leads to self-flocculation and filamentation for convenient downstream processing

The halophile Halomonas bluephagenesis has established itself as a cost-effective chassis in industrial bioproduction. However, downstream processing (DSP) expense is a persistent challenge. This study uses genetic knockout of exopolysaccharides (EPS-KO) in six industrially relevant H. bluephagenesis strains, each producing distinct polyhydroxyalkanoate (PHA), to evaluate their impact on reducing DSP costs. Remarkably, EPS-KO cells exhibited an unprecedented filamentous morphology, reaching lengths over 50 times (10–75 μm) that of standard cells. This unexpected behavior initially posed a challenge to industrial applicability due to rapid cell lysis under fermentation agitation. Systematic media supplementation of salt, carbon source, nitrogen, and essential minerals significantly influenced morphology, and tailored nutrient schemes that mitigated filamentation while maintaining production levels were designed. Scaled production in a 5000 L bioreactor demonstrated 85 % PHA and 96 g/L cell dry weight after 40 h fermentation, consistent with non-KO cells. During fermentation, EPS-KO enhanced cell-wall penetrability, reducing the need for high-cost γ-butyrolactone by 40 %. Additionally, a new innovative 5000 L FlipFlow bioreactor design cut rotation speed by 50 % and air input by 25 %. During DSP, centrifugation time decreased tenfold due to rapid cell self-flocculation (15–30 min), and the water and enzyme required for PHA purification was reduced by 30 % and 35 %, respectively. This study highlights the use of EPS-KO cells, a controlled media strategy, and low shear force FlipFlow bioreactor to successfully reduce DSP costs without sacrificing productivity. These novel findings represent a notable advancement in cost-saving strategies while presenting the intriguing discovery of media-controlled filamentous cell behavior.

Characterization of biodiversity and meat quality in Guizhou yellow cattle: Correlations among intrinsic factors

This study aimed to characterize meat quality diversity among Guizhou yellow cattle and investigate the correlations among intrinsic factors that affect beef quality. Various cuts including chuck roll, fore shank, topside, rib fingers, flank, brisket, and tenderloin were taken from the carcass of Sinan cattle, Guanling cattle, and the Simmental-Guanling crossbred cattle for meat quality comparisons. The results showed that meats of all three breeds displayed high water-holding capacity and desirable meat colors, but they were tough in texture. Variations among the breeds were identified, with Guanling cattle having darker meat than the crossbred cattle. The crossbreed had lower shear force indicating potential heterosis benefits, and possessed higher fat content. Guizhou yellow cattle were leaner and more abundant in protein and umami amino acids, potentially contributing to favorable flavor. The hierarchical cluster analysis and nutritional indices assessment implicated that the composition of fatty acids demonstrated a breed-specific effect in Guanling cattle, offering greater benefits in cardiovascular disease prevention. The increased quantity of vitamin A present in the majority of cuts from crossbred and Sinan cattle enhanced their nutritional value. By multivariate data analysis, we found that as the variations in physicochemical properties increased, the nutrient compositions in beef became more complex. Overall, this study demonstrated that meats from all three breeds were nutrient-balanced high-quality protein sources, although certain indexes may vary across cuts and breeds. These variations should be considered when developing breeding strategies in the future.

Effects of gender and slaughter age on physicochemical and quality traits of Korean Hanwoo striploin.

Hanwoo beef is in high demand because of its unique flavor, freshness, and high-fat content. However, the longer rearing period required to enhance marbling in Hanwoo cattle has adverse environmental consequences, such as greenhouse gas emissions and overall rearing costs. To address consumer preferences for leaner and healthier meat, the Korean meat industry has recently introduced Hanwoo heifer meat as an alternative source, but its quality traits are still unclear. Nevertheless, there is a limited body of research exploring the impact of Hanwoo gender (steer, heifer, and cow) and their corresponding slaughter ages on meat quality traits. This study looked into how gender affected the physicochemical and qualitative features of Hanwoo striploin at their respective slaughter ages. Results revealed that cow striploin has higher levels of moisture (66.81%) and protein (20.76%), whereas it contains lower levels of fat (10.66%) and cholesterol (34.66 mg/100 g). Regarding the physicochemical properties, cow striploin exhibited significantly lower shear force, color indexes, and soluble collagen (p < 0.05). However, chondroitin (1.19%) and muscle fiber area (1,545.23 μm2) were significantly higher in steer striploin than in heifer and cow (p < 0.05). Cow striploin exhibited significantly higher levels of oleic acid, unsaturated fatty acids (UFAs), and monounsaturated fatty acids (MUFAs) while having lower levels of eicosadienoic acid and atherogenic index compared to the other two groups. Cows and heifers had higher concentrations of amino acid metabolites than striploin from steers. Furthermore, bioactive metabolites such as carnitine and carnosine content were found higher in cow and heifer respectively. Overall, Hanwoo cattle gender influences the qualitative attributes of striploin; nevertheless, compared to steer and heifer striploin, cow striploin is a relatively good source of protein, fatty acid content, and metabolites conducive to a healthy diet.

Effect of accelerated aging on shelf-stability, product loss, sensory and biochemical characteristics in 2 lower quality beef cuts

The aim of this study was to determine the impact of accelerated aging (AA) on shelf stability, product loss, sensory and biochemical characteristics of 2 lower quality beef cuts. Triceps brachii (TB) and semimembranosus (SM) were collected and fabricated from 10 USDA Choice beef carcasses and assigned to 1 of 6 treatments: 3 d cooler aged (control), 21 d cooler aged, AA 49 °C for 2 h, AA 49 °C for 3 h, AA 54 °C for 2 h, and AA 54 °C for 3 h. The results showed that AA can decrease APC counts on steak surface and in purge and redness, but increase lightness and product loss of the steaks (P < 0.01). Lower shear force was also found for AA steaks compared to those from the control (P < 0.01), with the AA 54 °C treatments being comparable to 21 d cooler aging. However, the trained sensory panel determined AA steaks were less juicy and flavorful than those from the control and 21 d cooler aged samples (P < 0.05). There was no off-flavor detected in AA steaks though lipid oxidation was higher in AA samples than those in the control steaks (P < 0.01). The AA treatments stimulated cathepsin activity (P < 0.05), which may have enhanced the solubilization of stromal proteins and led to a different troponin-T degradation pattern compared to those from the 21 d aged samples (P < 0.01). Although AA is an economical and time-efficient method to increase tenderness of lower-quality beef cuts, further research is needed to determine strategies to mitigate the decrease in juiciness from AA treatments.

Analytical Modeling of Water Droplet Behavior at the Gas Channel Corner for Proton Exchange Membrane Fuel Cells

Abstract Water management is of significant importance to achieving high performance of proton exchange membrane fuel cells. In recent years, droplets emerged from the rib surface and accumulated at the channel corner have been found to be a crucial part of water flooding. In this study, an analytical model is first proposed to quantitatively estimate the variation in the morphology and dynamic behavior of growing droplets with consideration of the channel sidewall interaction. In order to predict the water geometry, the flow channel with compressed gas diffusion layer (GDL) is described mathematically, and water behavior at steady-state and dynamic state are both evaluated through the geometric and force analysis. The model results indicate that the droplet profile transforms from concave to convex when its size grows, in which process contact angles and channel shape play an important role. Compared with the graphite channel, the droplet in the metallic channel is more inclined to be adsorbed on the sidewall and GDL, resulting in a higher adhesion force and a lower gas shear force. The critical gas velocities for the detachment of droplets are quantitatively predicted to avoid water flooding. The model is helpful to understand the droplet behavior in the presence of channel sidewall interaction.

The rheology of interactions between leukocytes, platelets and the vessel wall in thrombo-inflammation.

Leukocytes and platelets must adhere to the wall of blood vessels to carry out their protective functions in inflammation and haemostasis. Recruitment is critically dependent on rheological variables (wall shear rate and stress, red cell aggregation and haematocrit) which affect delivery to the vessel wall as well as velocities and forces experienced there. Leukocyte recruitment is efficient only up to wall shear rates of about 300s-1 and usually restricted to low-shear post-capillary venules in inflammation. Being smaller, platelets experience lower velocities and shear forces adjacent to the wall and can adhere at much higher shear rates for haemostasis in arteries. In addition, we found quite different effects of variations in haematocrit or red cell aggregation on attachment of neutrophils or platelets, which also assist their separate recruitment in venules or arteries. However, it has become increasingly evident that inflammatory and thrombotic responses may occur together, with platelets promoting the adhesion and activation of neutrophils and monocytes. Indeed, it is 30 years since we demonstrated that platelets could cause neutrophils to aggregate in suspension and, when attached to a surface, could support selectin-mediated rolling of all leukocytes. Thrombin-activated platelets could further induce neutrophil activation and immobilisation. In some conditions, platelets could bind to intact endothelial monolayers and capture neutrophils or monocytes. Subsequently, we found that extracellular vesicles released by activated platelets (PEV) fulfilled similar functions when deposited on surfaces or bound to endothelial cells. In murine models, platelets or PEV could act as bridges for monocytes in inflamed vessels. Thus, leukocytes and platelets are rheologically adapted for their separate functions, while novel thrombo-inflammatory pathways using platelets or PEV may underlie pathogenic leukocyte recruitment.

Nanostructured lubricant additives for titanium alloy: Lubrication by the solid-liquid interface with Coulomb repulsion

In this work, the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid-liquid nanosized contact interface is taken, and the superior friction-reducing property of Cu3(PO4)2·3H2O (CuP) oil-based additives has been confirmed for titanium alloy. Three-dimensional (3D) CuP nanoflowers (CuP-Fs) with a strong capillary absorption effect are prepared to achieve the homogeneous mixing of solid CuP and lubricating oil. Lubrication by CuP-Fs additives for titanium alloy, friction coefficient (COF) can be reduced by 73.68%, and wear rate (WR) reduced by 99.69%. It is demonstrated that the extraordinary friction-reducing property is due to the repulsive solid-liquid interface with low viscous shear force originating from Coulomb repulsion between polar water molecules in CuP and non-polar oil molecules. However, any steric hindrance or connection between this repulsive solid-liquid interface will trigger the adhesion and increase the viscous shear force, for example, dispersant, hydrogen bondings, and shaky adsorbed water molecules. Besides, the lamellar thickness of CuP and the molecular size of lubricant both have a great influence on tribological properties. Here the lubrication mechanism based on interface Coulomb repulsion is proposed that may help broaden the scope of the exploration in low-friction nanomaterial design and new lubricant systems.

Evaluation of Fresh and Frozen Beef Strip Loins of Equal Aging Periods for Palatability Traits

Although studies evaluating freezing are prevalent, most have used varied postmortem aging times to facilitate study design. The lack of a comprehensive study evaluating equally aged fresh and frozen steaks prevents a true under-standing of the impact of freezing. Therefore, the objective of this study was to determine the eating quality and consumer perception differences between fresh and frozen beef steaks of 3 equal aging periods. Beef carcasses were selected from a processing plant on 2 kill dates 1 wk apart to allow for a 1-wk freezing period, fabricated, and aged for 21, 28, or 35 d. On the same day, all samples of equal aging periods were fed to consumer and trained sensory panelists, sheared for shear force, and powdered for lab assays. For consumer panels, the first 4 steaks were given with no additional information, whereas the last 4 steaks were served with the labels “previously frozen” or “fresh, never frozen.” The consumer panelists rated the frozen samples as more tender (P&amp;lt;0.05) than the fresh samples but found no other differences (P&amp;gt;0.05). Even when given additional information, the perception of quality was not impacted (P&amp;gt;0.05). Similarly, the trained panelists rated the frozen samples higher (P&amp;lt;0.05) than the fresh counterparts for overall tenderness, but the fresh samples scored higher (P&amp;lt;0.05) for initial and sustained juiciness. Supporting the sensory data, the frozen steaks had lower (P&amp;lt;0.05) shear force values regardless of the aging period. However, the fresh samples resulted in lower (P&amp;lt;0.05) purge and cook loss. Although some meat quality factors were impacted by freezing, the overall eating quality and perception of quality were not negatively impacted. Therefore, frozen meat should not be discounted due to the eating quality or perception of the quality of beef steaks.