Comparison of a low molecular weight and a macromolecular surfactant as foaming agents for injectable self setting hydroxyapatite foams: Polysorbate 80 versus gelatine

Hydroxyapatite foams are potential synthetic bone grafting materials or scaffolds for bone tissue engineering. A novel method to obtain injectable hydroxyapatite foams consists in foaming the liquid phase of a calcium phosphate cement. In this process, the cement powder is incorporated into a liquid foam, which acts as a template for macroporosity. After setting, the cement hardens maintaining the macroporous structure of the foam. In this study a low molecular weight surfactant, Polysorbate 80, and a protein, gelatine, were compared as foaming agents of a calcium phosphate cement. The foamability of Polysorbate 80 was greater than that of gelatine, resulting in higher macroporosity in the set hydroxyapatite foam and higher macropore interconnectivity. Gelatine produced less interconnected foams, especially at high concentrations, due to a higher liquid foam stability. However it increased the injectability and cohesion of the foamed paste, and enhanced osteoblastic-like cell adhesion, all of them important properties for bone grafting materials.     

Adding functionalities to precomputed holograms with random mask multiplexing in holographic optical tweezers

In this study, we present a method designed to generate dynamic holograms in holographic optical tweezers. The approach combines our random mask encoding method with iterative high-efficiency algorithms. This hybrid method can be used to dynamically modify precalculated holograms, giving them new functionalities-temporarily or permanently-with a low computational cost. This allows the easy addition or removal of a single trap or the independent control of groups of traps for manipulating a variety of rigid structures in real time.     

Unpredicted Aberrant Splicing Products Identified in Postmortem Sudden Cardiac Death Samples

Molecular screening for pathogenic mutations in sudden cardiac death (SCD)-related genes is common practice for SCD cases. However, test results may lead to uncertainty because of the identification of variants of unknown significance (VUS) occurring in up to 70% of total identified variants due to a lack of experimental studies. Genetic variants affecting potential splice site variants are among the most difficult to interpret. The aim of this study was to examine rare intronic variants identified in the exonic flanking sequence to meet two main objectives: first, to validate that canonical intronic variants produce aberrant splicing; second, to determine whether rare intronic variants predicted as VUS may affect the splicing product. To achieve these objectives, 28 heart samples of cases of SCD carrying rare intronic variants were studied. Samples were analyzed using 85 SCD genes in custom panel sequencing. Our results showed that rare intronic variants affecting the most canonical splice sites displayed in 100% of cases that they would affect the splicing product, possibly causing aberrant isoforms. However, 25% of these cases (1/4) showed normal splicing, contradicting the in silico results. On the contrary, in silico results predicted an effect in 0% of cases, and experimental results showed >20% (3/14) unpredicted aberrant splicing. Thus, deep intron variants are likely predicted to not have an effect, which, based on our results, might be an underestimation of their effect and, therefore, of their pathogenicity classification and family members’ follow-up.     

The necessity of sample quality assessment in 14C AMS dating: The case of Cova des Pas (Menorca – Spain)

The Cova des Pas cave is a karstic cave in the cliffs of the Barranc (canyon) de Trebalúger. It is a small cave only 6.5 m deep, 4.5 m wide and 1.7 m high. Yet more than 70 burials, in foetal position, from the Early Iron Age were found in this small cave. The conservation of the archaeological remains was very unusual. Not only wood, ropes and other plant material was found, but also remains of body tissue, hair and leather. In spite of the remarkable preservation of the bodies and artefacts, the state of conservation of the bone material was very bad. The bones contained little and heavily deteriorated collagen and the organic plant material was very fragile. The special environmental conditions of the cave are the cause of these unusual preservation conditions. Although the cave is situated in a limestone cliff, the soil of the cave is very acid. Unexpectedly bad sample quality seemed to be the major drawback for AMS radiocarbon dating on hair, wood, ropes and bone collagen, as well as on bio-apatite.     

Quantitative Evaluation of Register Pressure on Software Pipelined Loops

Software Pipelining is a loop scheduling technique that extracts loop parallelism by overlapping the execution of several consecutive iterations. One of the drawbacks of software pipelining is its high register requirements, which increase with the number of functional units and their degree of pipelining. This paper analyzes the register requirements of software pipelined loops. It also evaluates the effects on performance of the addition of spill code. Spill code is needed when the number of registers required by the software pipelined loop is larger than the number of registers of the target machine. This spill code increases memory traffic and can reduce performance. Finally, compilers can apply transformations in order to reduce the number of memory accesses and increase functional unit utilization. The paper also evaluates the negative effect on register requirements that some of these transformations might produce on loops.     

Analysis,design,and experimental evaluation of power calculation in digital droop-controlled parallel microgrid inverters

Parallel operation of distributed generation is an important topic for microgrids,which can provide a highly reliable electric supply service and good power quality to end customers when the utility is unavailable.However,there is a well-known limitation:the power sharing accuracy between distributed generators in a parallel operation.Frequency and voltage droop is a well-established control method for improving power sharing performance.In this method,the active and reactive power calculations are used to adjust the frequency and amplitude of the output voltage.This paper describes the digital implementation of a droop method,and analyzes the influence of power calculation on droop method performance.According to the analysis,the performance of droop control in a digital control system is limited by the accuracy and speed of the power calculation method.We propose an improved power calculation method based on p-q theory to improve the performance of the droop control method,and we compare our new method with two traditional power calculation methods.Finally,simulation results and experimental results from a three single-phase 1-kW-inverter system are presented,which validate the performance of our proposed method.     

A surface mesh smoothing and untangling method independent of the CAD parameterization

A method to optimize triangular and quadrilateral meshes on parameterized surfaces is proposed. The optimization procedure relocates the nodes on the surface to improve the quality (smooth) and ensures that the elements are not inverted (untangle). We detail how to express any measure for planar elements in terms of the parametric coordinates of the nodes. The extended measures can be used to check the quality and validity of a surface mesh. Then, we detail how to optimize any Jacobian-based distortion measure to obtain smoothed and untangled meshes with the nodes on the surface. We prove that this method is independent of the surface parameterization. Thus, it can optimize meshes on CAD surfaces defined by low-quality parameterizations. The examples show that the method can optimize meshes composed by a large number of inverted elements. Finally, the method can be extended to obtain high-order meshes with the nodes on the CAD surfaces.     

Invertase activity in fresh and processed honeys

The enzymatic activities of 147 samples of commercially produced Spanish polyfloral and monofloral honeys are reported. Important variations in invertase activity and peroxide accumulation were determined to obtain objective information related to honey quality. Variations from 4.04 (Robinia pseudoacacia) to 25.61 g sucrose hydrolysed per 100 g h⁻¹ (SN) (Castanea sativa) and from 11.31 (Erica vagans) to 45.25 µg H₂O₂ g⁻¹ h⁻¹ (Hedysarum coronarium) were detected, with a range from 10.57 to 46.2 SN in polyfloral honeys. Honeys from Erica spp had different invertase activities—high for E cinerea (18.3 SN) and low for E vagans (8.36 SN). The different heating processes of honey have been evaluated to determine the best treatment for preserving invertase activity. The hydroxymethylfurfural content is not a sufficiently good indicator of the degree of deterioration of honey. Another objective was to assess the use of invertase activity in honey quality legislation. © 2000 Society of Chemical Industry     

A performance index for semicoherent structures

The index introduced here provides a normalized measure of the effectiveness of any semicoherent structure. We study the mathematical properties of the index and derive different axiomatic characterizations for it. Moreover, close relationships are shown to reliability functions and also to the Birnbaum structural importance measure—for which twice the performance index plays the role of potential function—that give rise to computational procedures. Some numerical examples illustrate the application of the index.