The NASA Lewis Research Center Internal Fluid Mechanics Facility

An experimental facility specifically designed to investigate internal fluid duct flows is described. It is built in a modular fashion so that a variety of internal flow test hardware can be installed in the facility with minimal facility reconfiguration. The facility and test hardware interfaces are discussed along with design constraints of future test hardware. The plenum flow conditioning approach is also detailed. Available instrumentation and data acquisition capabilities are discussed. The incoming flow quality was documented over the current facility operating range. The incoming flow produces well behaved turbulent boundary layers with a uniform core. For the calibration duct used, the boundary layers approached 10 percent of the duct radius. Freestream turbulence levels at the various operating conditions varied from 0.64 to 0.69 percent of the average freestream velocity

A novel kinematics analysis method using quaternion interpolation – a case study in frog jumping

Spherical Linear Interpolation (SLERP) has long been used in computer animation to interpolate movements between two 3D orientations. We developed a forward kinematics (FK) approach using quaternions and SLERP to predict how frogs modulate jump kinematics between start posture and takeoff. Frog limb kinematics have been studied during various activities, yet the causal link between differences in joint kinematics and locomotor variation remains unknown. We varied 1) takeoff angle from 8 to 60 degrees; 2) turn angle from 0 to 18 degrees; and 3) initial body pitch from 0 to 70 degrees. Simulations were similar to experimentally observed frog kinematics. Findings suggest a fundamental mechanism whereby limb elevation is modulated by thigh and shank adduction. Forward thrust is produced by thigh and proximal foot retraction with little contribution from the shank except to induce asymmetries for turning. Kinematic shifts causing turns were subtle, marked only by slight counter-rotation of the left versus right shank as well as a 10% timing offset in proximal foot adduction. Additionally, inclining initial body tilt influenced the centre of mass trajectory to determine direction of travel at takeoff. Most importantly, our theory suggests firstly that the convergence of leg segment rotation axes toward a common orientation is crucial both for limb extension and for coordinating jump direction; and, secondly, the challenge of simulating 3D kinematics is simplified using SLERP because frog limbs approximately follow linear paths in unit quaternion space. Our methodology can be applied more broadly to study living and fossil frog taxa as well as to inspire new control algorithms for robotic limbs

Evaluation of a technique to generate artificially thickened boundary layers in supersonic and hypersonic flows

The feasibility of using a contoured honeycomb model to generate a thick boundary layer in high-speed, compressible flow was investigated. The contour of the honeycomb was tailored to selectively remove momentum in a minimum of streamwise distance to create an artificially thickened turbulent boundary layer. Three wind tunnel experiments were conducted to verify the concept. Results indicate that this technique is a viable concept, especially for high-speed inlet testing applications. In addition, the compactness of the honeycomb boundary layer simulator allows relatively easy integration into existing wind tunnel model hardware

EVALUATION OF L-ARGININE/NITRIC OXIDE METABOLIC PATHWAY IN ERYTHROCYTES IN RELATION WITH OXIDATIVE STRESS: FOCUS ON DIFFERENT CARDIOVASCULAR DISEASES

Background: A decreased nitric oxide (NO) bioavailability and an increased oxidative stress play a pivotal role in different cardiovascular pathologies. Recent studies have shown that red blood cells (RBCs) participate in NO formation in the bloodstream. Aim: The aim of this study was to assess the L-arginine (Arg)/NO pathway and the oxidative stress status in RBCs and in plasma of patients with microvascular angina (MVA), investigating similarities and differences with respect to coronary artery disease (CAD) patients or healthy controls (Ctrl). Materials and Methods: Analytes involved in Arg/NO pathway and the ratio between the oxidized and the reduced forms of glutathione, as index of oxidative stress, were measured by liquid-chromatography tandem mass spectrometry (LC-MS/MS). The arginase and the NO synthase (NOS) expression were assessed by immunofluorescence staining. NOS activity was evaluated by ex-vivo experiments through the conversion of L-[15N2]arginine to L-[15N]citrulline. Results: Both MVA and CAD patients showed alterations in the ability of RBCs to produce NO, based on an increase of NO synthesis inhibitors, parallel to that found in plasma, a reduction of NOS expression and activity and an increased arginase expression. When summary scores of NO synthesis and of oxidative stress were computed, both patient groups were associated with a positive oxidative score and a negative NO score, with the CAD group located in a more extreme position with respect to Ctrl. Conclusions: This finding points out to an impairment of the capacity of RBCs to produce NO in pathological conditions characterized by alteration at the microvascular bed with/without no significant coronary stenosis

In vivo cranial bone strain and bite force in the agamid lizard Uromastyx geyri

In vivo bone strain data are the most direct evidence of deformation and strain regimes in the vertebrate cranium during feeding and can provide important insights into skull morphology. Strain data have been collected during feeding across a wide range of mammals; in contrast, in vivo cranial bone strain data have been collected from few sauropsid taxa. Here we present bone strain data recorded from the jugal of the herbivorous agamid lizard Uromastyx geyri along with simultaneously recorded bite force. Principal and shear strain magnitudes in Uromastyx geyri were lower than cranial bone strains recorded in Alligator mississippiensis, but higher than those reported from herbivorous mammals. Our results suggest that variations in principal strain orientations in the facial skeleton are largely due to differences in feeding behavior and bite location, whereas food type has little impact on strain orientations. Furthermore, mean principal strain orientations differ between male and female Uromastyx during feeding, potentially because of sexual dimorphism in skull morphology

Locomotor, ecological and phylogenetic drivers of skeletal proportions in frogs

Frogs exhibit complex anatomical features of the pelvis, limbs and spine, long assumed to represent specialisations for jumping. Yet frogs employ a wide range of locomotor modes, with several taxa featuring primary locomotor modes other than jumping. Using a combination of techniques (CT imaging and 3D visualization, morphometrics, phylogenetic mapping), this study aims to determine the link between skeletal anatomy and locomotor style, habitat type and phylogenetic history, shedding new light on how functional demands impact morphology. Body and limb measurements for 164 taxa from all the recognised anuran families are extracted from digitally segmented CT scans of whole frog skeletons and analysed using various statistical techniques. We find that the expansion of the sacral diapophyses is the most important variable for predicting locomotor mode, which was more closely correlated with frog morphology than either habitat type or phylogenetic relationships. Predictive analyses suggest that skeletal morphology is a useful indicator of jumping but less so for other locomotor modes, suggesting that there is a wide range of anatomical solutions to performing locomotor styles such as swimming, burrowing or walking

Optimizaciónde las variables tecnológicas en la producción de un probiótico para camarones

Aim: To optimize the technological variables engaged in the manufacture of a probiotic for shrimp. Methods: This research was based on experimental designs oriented to phenomenological mathematical modeling of the process to identify the main design variables. The product cost sheet was used to create the economic model that fits such variables. The objective-function was to minimize the unit cost of the product. Restrictions of design variables were established, and their optimal values were estimated through the use of multi-criteria computer optimizing tools. Results: The initial sucrose concentration produced in the culture medium was 132 g/L, at a shaking speed of 1.67 s-1, air flow equal to 0.025 L/L.h, and fermentation time 8.5 h, which minimized the unit cost of the product to 5.31 $/L of product. This value was quite below$ 31.50/L, which is the price of imported probiotic Epicin, used to breed shrimp larvae. Conclusions: The sale of this product produces a revenue of $478 483.20/year to the Center of Genetic Engineering and Biotechnology of Camagüey, leading to savings of approximately$ 40 000 US yearly in savings for Yaguacam Basic Production Company, through import substitution. Additionally, its use has led to a reduction in antibiotic use, increased quality and quantity of post larvae, and an overall positive impact for the company.Objetivo: Optimizar las variables tecnológicas que inciden en el proceso de producción de un probiótico para camarones. Métodos: Se emplearon diseños experimentales orientados a la modelación matemática fenomenológica del proceso para identificar las variables de diseño fundamentales. Se utilizó la ficha de costo del producto para confeccionar el modelo económico en función de estas variables. Se definió como función objetivo minimizar el costo unitario del producto. Se establecieron las restricciones de las variables de diseño y se determinaron sus valores óptimos mediante el empleo de herramientas computacionales de optimización multicriterio. Resultados:Se obtuvo que una concentración inicial de sacarosa en el medio de cultivo igual a 132 g/L, una velocidad de agitación de 1,67 s-1, un flujo de aire igual a 0,025 L/L.h y un tiempo de fermentación de 8,5 h minimizan el costo unitario del producto hasta 5,31 $/L de producto, valor muy inferior a los 31,50$/L que es el precio del probiótico de importación Epicin que se emplea en la cría de larvas de camarones. Conclusiones: La venta del producto genera una ganancia neta de 478 483,20 $/año para el Centro de Ingeniería Genética y Biotecnología de Camagüey, un ahorro de cerca de 40 000 USD anuales a la Unidad Empresarial de Base Yaguacam por concepto de sustitución de importaciones y su uso ha permitido la disminución del empleo de antibióticos, el incremento de la calidad y cantidad de las postlarvas y un impacto económico positivo en la entidad. &nbsp

Anatomy and Cranial Functional Morphology of the Small-Bodied Dinosaur Fruitadens haagarorum from the Upper Jurassic of the USA

Heterodontosaurids are an important but enigmatic and poorly understood early radiation of ornithischian dinosaurs. The late-surviving heterodontosaurid Fruitadens haagarorum from the Late Jurassic (early Tithonian) Morrison Formation of the western USA is represented by remains of several small (<1 metre total body length, <1 kg body mass) individuals that include well-preserved but incomplete cranial and postcranial material. Fruitadens is hypothesized to represent one of the smallest known ornithischian dinosaurs. We describe the cranial and postcranial anatomy of Fruitadens in detail, providing comparisons to all other known heterodontosaurid taxa. High resolution micro-CT data provides new insights into tooth replacement and the internal anatomy of the tooth-bearing bones. Moreover, we provide a preliminary functional analysis of the skull of late-surviving heterodontosaurids, discuss the implications of Fruitadens for current understanding of heterodontosaurid monophyly, and briefly review the evolution and biogeography of heterodontosaurids. The validity of Fruitadens is supported by multiple unique characters of the dentition and hindlimb as well as a distinct character combination. Fruitadens shares highly distinctive appendicular characters with other heterodontosaurids, strengthening monophyly of the clade on the basis of the postcranium. Mandibular morphology and muscle moment arms suggest that the jaws of late-surviving heterodontosaurids, including Fruitadens, were adapted for rapid biting at large gape angles, contrasting with the jaws of the stratigraphically older Heterodontosaurus, which were better suited for strong jaw adduction at small gapes. The lack of wear facets and plesiomorphic dentition suggest that Fruitadens used orthal jaw movements and employed simple puncture-crushing to process food. In combination with its small body size, these results suggest that Fruitadens was an ecological generalist, consuming select plant material and possibly insects or other invertebrates

Bite force and cranial bone strain in four species of lizards

In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared to mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitudes. Within individuals the most consistent determinants of variance in bone strain magnitudes are gage location and bite point, with the importance of bite force varying between individuals. Inter-site variance in strain magnitudes—strain gradient—is present in all individuals, and varies with bite point. Between individuals within species, variance in strain magnitude is driven primarily by variation in bite force, not gage location or bite point, suggesting that inter-individual variation in patterns of strain magnitude is minimal. Between species, variation in strain magnitudes is significantly impacted by bite force and species membership, as well as by interactions between gage location, species, and bite point. Independent of bite force, species differences in cranial strain magnitudes may reflect selection for different cranial morphology in relation to feeding function, but what these performance criteria are is not clear. The relatively low strain magnitudes in Iguana and Uromastyx compared to other lizards may be related to their herbivorous diet. Cranial kinesis and the presence or absence of postorbital and supratemporal bars are not important determinants of inter-specific variation in strain magnitudes

Tackling the grapevine Pectate Lyase gene family and its role in the berry texture determination

Grapevine (Vitis vinifera L.) is one of the most commercially valuable fruit trees worldwide. Table grapes represent an important economic sector, where consumers highly appreciate the berry firmness trait. Although several studies have addressed the key role of the cell wall in fruit firmness, the main players among cell wall degrading enzymes during fruit ripening are still unclear. This work characterizes the grapevine Pectate Lyase (VvPL) gene family which catalyses the eliminative cleavage of de-esterified pectin during the berry development. Using the latest grapevine genome assembly and annotation, 17 members of the family containing the PL domain were identified. To identify the VvPL members most involved in pectin degradation during fruit softening, an in-silico analysis in Expression Atlas and in public RNA-Seq repositories was performed. Additionally, gene expression of the VvPL genes was evaluated in table grape varieties showing contrasting texture profiles. Our results demonstrated that specific VvPL genes were up-regulated in the softer variety compared to the firmer one, suggesting their active role in the softening process during berry development. Furthermore, two VvPL genes were selected for functional characterization via genome editing with CRISPR/Cas9 technology in the table grape variety ‘Sugraone