185 research outputs found

    Ordering of apolar and polar solutes in nematic solvents

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    The quadrupolar splittings of deuteriated para- and ortho-dichlorobenzene (1,4-DCB and 1,2-DCB, respectively) are measured by nuclear magnetic resonance(NMR) in the nematic solvents hexyl- and pentyloxy-substituted diphenyl diacetylene (DPDA-C6 and DPDA-OC5, respectively). Measurements are taken for all four combinations of the nominally apolar (1,4-DCB) and polar (1,2-DCB) solutes in the apolar (DPDA-C6) and polar (DPDA-OC5) solvents, and throughout the entire nematic temperature range of the solutions. The temperature dependence of the second-rank orientational order parameters of the solutes are obtained from these measurements and the respective order parameters of the mesogenic cores of solvent molecules are obtained independently from carbon-13 NMR measurements. The order parameter profiles of the two solutes are found to be very different but show little variation from one solvent to the other. The results are analyzed and interpreted in terms of the underlying molecular interactions using atomistic solvent–solute potentials. The influence of electrostaticinteractions on solute ordering is directly evaluated by computing the order parameters with and without the electrostatic component of the atomistic potential. It is observed to be small. It is also found that the important interactions in these solvent–solute systems are operative over short intermolecular distances for which the representation of the partial charge distributions in terms of overall molecular dipole and quadrupole moments is not valid

    Sensory professionals’ perspective on the possibilities of using facial expression analysis in sensory and consumer research

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    The increase in digitalization, software applications, and computing power has widened the variety of tools with which to collect and analyze sensory data. As these changes continue to take place, examining new skills required among sensory professionals is needed. The aim with this study was to answer the following questions: (a) How did sensory professionals perceive the opportunities to utilize facial expression analysis in sensory evaluation work? (b) What skills did the sensory professionals describe they needed when utilizing facial expression analysis? Twenty-two sensory professionals from various food companies and universities were interviewed by using semistructural thematic interviews to map development intentions from facial expression recognition data as well as to describe the established skills that were needed. Participants' facial expressions were first elicited by an odor sample during a sensory evaluation task. The evaluation was video recorded to characterize a facial expression software response (FaceReader (TM)). The participants were interviewed regarding their opinions of the data analysis the software produced. The study findings demonstrate how using facial expression analysis contains personal and field-specific perspectives. Recognizability, associativity, reflectivity, reliability, and suitability were perceived as a personal perspective. From the field-specific perspective, professionals considered the received data valuable only if they had skills to interpret and utilize it. There is a need for an increase in training not only in IT, mathematics, statistics, and problem-solving, but also in skills related to self-management and ethical responsibility.Peer reviewe

    Magnetic field-dependent interplay between incoherent and Fermi liquid transport mechanisms in low-dimensional tau phase organic conductors

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    We present an electrical transport study of the 2-dimensional (2D) organic conductor tau-(P-(S,S)-DMEDT-TTF)_2(AuBr)_2(AuBr_2)_y (y = 0.75) at low temperatures and high magnetic fields. The inter-plane resistivity rho_zz increases with decreasing temperature, with the exception of a slight anomaly at 12 K. Under a magnetic field B, both rho_zz and the in-plane resistivity plane rho_xx show a pronounced negative and hysteretic magnetoresistance with Shubnikov de Haas (SdH)oscillations being observed in some (high quality)samples above 15 T. Contrary to the predicted single, star-shaped, closed orbit Fermi surface from band structure calculations (with an expected approximate area of 12.5% of A_FBZ), two fundamental frequencies F_l and F_h are detected in the SdH signal. These orbits correspond to 2.4% and 6.8% of the area of the first Brillouin zone(A_FBZ), with effective masses F_l = 4.0 +/- 0.5 and F_h = 7.3 +/- 0.1. The angular dependence, in tilted magnetic fields of F_l and F_h, reveals the 2D character of the FS and Angular dependent magnetoresistance (AMRO) further suggests a FS which is strictly 2-D where the inter-plane hopping t_c is virtually absent or incoherent. The Hall constant R_xy is field independent, and the Hall mobility increases by a factor of 3 under moderate magnetic fields. Our observations suggest a unique physical situation where a stable 2D Fermi liquid state in the molecular layers are incoherently coupled along the least conducting direction. The magnetic field not only reduces the inelastic scattering between the 2D metallic layers, but it also reveals the incoherent nature of interplane transport in the AMRO spectrum. The apparent ferromagnetism of the hysteretic magnetoresistance remains an unsolved problem.Comment: 33 pages, 11 figure

    Cloud Computing As a Tool for Enhancing Ecological Goals?

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    Cloud computing has been introduced as a promising information technology (IT) that embodies not only economic advantages in terms of increased efficiency but also ecological gains through saving energy. The latter has become particularly important in view of the rising energy costs of IT. The present study analyzes whether necessary preconditions for accepting cloud computing as a new infrastructure, such as awareness and perceived net value, exist on the part of the users. The analysis is based on a combined research framework of the theory of reasoned action (TRA) and the technology acceptance model (TAM) in a cloud computing setting. Two consumer surveys, the one to elicit beliefs and the second to gain insight into the ranking of the variables, are employed. This study uses structural equation modeling (SEM) to evaluate the hypotheses. The results indicate support for the proposed research framework. Surprisingly however, the ecological factor does not play a role in forming cloud computing intentions, regardless of prior knowledge or experience. Empirical evidence of this study suggests increasing efforts for informing actual and potential users, particularly in respect to possible ecological advantages through applying the new IT infrastructure

    Molecular networks of human muscle adaptation to exercise and age

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    Physical activity and molecular ageing presumably interact to precipitate musculoskeletal decline in humans with age. Herein, we have delineated molecular networks for these two major components of sarcopenic risk using multiple independent clinical cohorts. We generated genome-wide transcript profiles from individuals (n = 44) who then undertook 20 weeks of supervised resistance-exercise training (RET). Expectedly, our subjects exhibited a marked range of hypertrophic responses (3% to +28%), and when applying Ingenuity Pathway Analysis (IPA) up-stream analysis to ~580 genes that co-varied with gain in lean mass, we identified rapamycin (mTOR) signaling associating with growth (P = 1.4×10−30). Paradoxically, those displaying most hypertrophy exhibited an inhibited mTOR activation signature, including the striking down-regulation of 70 rRNAs. Differential analysis found networks mimicking developmental processes (activated all-trans-retinoic acid (ATRA, Z-score = 4.5; P = 6×10−13) and inhibited aryl-hydrocarbon receptor signaling (AhR, Z-score = −2.3; P = 3×10−7)) with RET. Intriguingly, as ATRA and AhR gene-sets were also a feature of endurance exercise training (EET), they appear to represent “generic” physical activity responsive gene-networks. For age, we found that differential gene-expression methods do not produce consistent molecular differences between young versus old individuals. Instead, utilizing two independent cohorts (n = 45 and n = 52), with a continuum of subject ages (18–78 y), the first reproducible set of age-related transcripts in human muscle was identified. This analysis identified ~500 genes highly enriched in post-transcriptional processes (P = 1×10−6) and with negligible links to the aforementioned generic exercise regulated gene-sets and some overlap with ribosomal genes. The RNA signatures from multiple compounds all targeting serotonin, DNA topoisomerase antagonism, and RXR activation were significantly related to the muscle age-related genes. Finally, a number of specific chromosomal loci, including 1q12 and 13q21, contributed by more than chance to the age-related gene list (P = 0.01–0.005), implying possible epigenetic events. We conclude that human muscle age-related molecular processes appear distinct from the processes regulated by those of physical activity

    Magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries: protocol for a systematic review of diagnostic accuracy

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    Background Adult brachial plexus injuries (BPI) are becoming more common. The reconstruction and prognosis of pre-ganglionic injuries (root avulsions) are different to other types of BPI injury. Preoperative magnetic resonance imaging (MRI) is being used to identify root avulsions, but the evidence from studies of its diagnostic accuracy are conflicting. Therefore, a systematic review is needed to address uncertainty about the accuracy of MRI and to guide future research. Methods We will conduct a systematic search of electronic databases alongside reference tracking. We will include studies of adults with traumatic BPI which report the accuracy of preoperative MRI (index test) against surgical exploration of the roots of the brachial plexus (reference standard) for detecting either of the two target conditions (any root avulsion or any pseudomeningocoele as a surrogate marker of root avulsion). We will exclude case reports, articles considering bilateral injuries and studies where the number of true positives, false positives, false negatives and true negatives cannot be derived. The methodological quality of the included studies will be assessed using a tailored version of the QUADAS-2 tool. Where possible, a bivariate model will be used for meta-analysis to obtain summary sensitivities and specificities for both target conditions. We will investigate heterogeneity in the performance of MRI according to field strength and the risk of bias if data permits. Discussion This review will summarise the current diagnostic accuracy of MRI for adult BPI, identify shortcomings and gaps in the literature and so help to guide future research
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