Determination of Young's modulus of dental composites: A phenomenological model

The Young's moduli of isotropic dental restorative composites are determined with a non-destructive dynamic method, which is based on the measurement of the duration of the fundamental period for the first harmonic of a freely oscillating sample. Statistical analysis of these results yields a phenomenological model in which Young's modulus is given by an exponential rule of mixtures of the matrix phase and the filler phase of the composites. It is found that this phenomenological rule is substantiated empirically.     

Understanding Computer Users With Tetraplegia: Survey of Assistive Technology Users

An online survey in the form of a questionnaire was conducted to obtain the opinion of computer users with tetraplegia on their current computer interfaces and to assess desirable applications for future independent control using assistive devices. The survey included questions related to information about the respondents' injury/disease, everyday activities and social life, electronic devices and computer programs, evaluation of computer interfaces, and desirable applications for assistive devices. The survey was distributed via tetraplegia associations, magazines, and Internet forums mainly in Denmark and Sweden, but also through other European and American associations. Thirty-one completed questionnaires were collected from individuals with spinal cord injury and other neuromuscular diseases that resulted in tetraplegia. Respondents evaluated gaze and head trackers; speech recognition systems; chin, mouth, and hand joysticks; sip and puff interfaces; and typing sticks. Most interfaces were evaluated in a range from neutral to good. Users expressed a desire for applications to independently control wheelchairs, television sets, doors, and windows. This is, as far as is known, the first study that compares a wide range of current commercial computer interfaces that have been used as part of the users' everyday lives. The answers are useful for designing and developing alternative computer interfaces and assistive devices and for computer-interface users to identify a computer-interface fitting more to his or her needs.     

Effect of high-oxygen atmosphere packaging on mechanical properties of single muscle fibres from bovine and porcine <Emphasis Type="Italic">longissimus dorsi</Emphasis>

The effect of storage in high-oxygen atmosphere packaging for 48 h at 4 °C on the myofibrillar component of meat toughness was studied performing tensile tests on single muscle fibres, isolated from beef and pork longissimus dorsi (LD). Storage of bovine LD for 48 h in the presence of oxygen significantly increased the breaking strength of single muscle fibres when compared with storage in a 100% nitrogen atmosphere. In contrast, the breaking strength of porcine LD stored for 2 days post-mortem in the presence of oxygen in the packages was not influenced.     

Analysing the Effect of Partner Characteristics on the Performance of Horizontal Carrier Collaborations

Networks and Spatial Economics - In order to survive under the ever increasing pressure to operate more efficiently, transportation companies are obliged to adopt a collaborative focus. Although...     

Relationship between haptoglobin and serum amyloid A in milk and milk quality

The objective of this study was to evaluate relationships between the presence in milk of the major bovine acute phase proteins, haptoglobin (Hp) and serum amyloid A (SAA), and milk quality parameters. Composite milk samples were collected from 89 clinically healthy dairy cows and analysed for Hp and SAA, total protein, casein, and whey protein levels, casein number, proteolysis, total fat and lactose levels, and somatic cell count (SCC). Milk samples with detectable levels of Hp showed lower total protein and casein levels than those samples without Hp, whereas milk samples with detectable levels of SAA had lower casein number and lactose level than samples without detectable SAA. Samples with detectable levels of acute phase proteins also showed an elevated SCC. The results suggest that the presence of Hp and SAA in milk might indicate unfavourable changes in milk composition, especially in relation to protein quality.     

Brain-Computer Interfaces, Virtual Reality, and Videogames

Major challenges must be tackled for brain-computer interfaces to mature into an established communications medium for VR applications, which will range from basic neuroscience studies to developing optimal peripherals and mental gamepads and more efficient brain-signal processing techniques.     

Studying the use of fuzzy inference systems for motor imagery classification.

This paper studies the use of fuzzy inference systems (FISs) for motor imagery classification in electroencephalography (EEG)-based brain-computer interfaces (BCIs). The results of the four studies achieved are promising as, on the analysed data, the used FIS was efficient, interpretable, showed good capabilities of rejecting outliers and offered the possibility of using a priori knowledge.     

The Antimicrobial Activity of Peripheral Blood Neutrophils Is Altered in Patients with Primary Ciliary Dyskinesia

The airways of patients with primary ciliary dyskinesia (PCD) contain persistently elevated neutrophil numbers and CXCL8 levels. Despite their abundance, neutrophils fail to clear the airways from bacterial infections. We investigated whether neutrophil functions are altered in patients with PCD. Neutrophils from patients and healthy controls (HC) were isolated from peripheral blood and exposed to various bacterial stimuli or cytokines. Neutrophils from patients with PCD were less responsive to low levels of fMLF in three different chemotaxis assays (p < 0.05), but expression of the fMLF receptors was unaltered. PCD neutrophils showed normal phagocytic function and expression of adhesion molecules. However, PCD neutrophils produced less reactive oxygen species upon stimulation with bacterial products or cytokines compared to HC neutrophils (p < 0.05). Finally, the capacity to release DNA, as observed during neutrophil extracellular trap formation, seemed to be reduced in patients with PCD compared to HC (p = 0.066). These results suggest that peripheral blood neutrophils from patients with PCD, in contrast to those of patients with cystic fibrosis or COPD, do not show features of over-activation, neither on baseline nor after stimulation. If these findings extend to lung-resident neutrophils, the reduced neutrophil activity could possibly contribute to the recurrent respiratory infections in patients with PCD.     

Comparison of methodologies for externality assessment

The production of energy causes different kinds of damage to the environment depending on the specific type of technology used in producing a given energy supply. The common term that expresses the costs of these environmental damages is externalities. These costs are not included in the cost and price structure faced by the producer and the consumer. During the last few years, external costs related to power production technologies have been calculated making use of different methodologies. The external costs may turn out to be very different for the same fuel cycle depending on the methodology that has been used to assess the externalities. The article will focus on some of the most important reasons for differences in the numbers. To illustrate the importance of knowing the exact data and assumptions used, two studies using the same approach and with integrated computer models are compared. The models are based on the same concept with air dispersion modules and dose–response functions for the calculation of impacts. Although the models are comparable, the resulting external costs turn out to differ with a factor of five in the two studies for the same power plant due to different assumptions, different dose–response functions used and different impacts included in the studies. In the paper the most important differences to be aware of will be illustrated.     

Instabilities when using a standard (T/3) rushton turbine for stirring as foam disruption (SAFD)

The concept of using the upper stirrer for foam disruption in a bioreactor agitated by multiple impellers has recently been published by Hoeks et al. (1997). This concept, stirring as foam disruption (SAFD), was shown by them to be effective with a range of impellers. However, the commonly used (so‐called) standard Rushton turbine of one‐third the fermenter diameter was not included. This paper fills that important gap. By measuring the foam height, the holdup, the power draw and the velocities of the liquid in the dispersion just below its top surface, it is concluded that the SAFD concept does not work well with the standard Rushton turbine. This is because the amount of broth for which foam can be disrupted is less than that found with all the other impellers tested to date; and even when foam disruption occurs, significant flow instabilities and torque fluctuations are found. Perhaps the poor performance of this impeller, which has been used so frequently in industry and in academic studies, explains why the concept of SAFD was not developed earlier.