Crystallization of medium length 1-alcohols in mesoporous silicon: An X-ray diffraction study

The linear 1-alcohols n-C16H33OH, n-C17H35OH, n-C19H37OH have been imbibed and solidified in lined up, tubular mesopores of silicon with 10 nm and 15 nm mean diameters, respectively. X-ray diffraction measurements reveal a set of six discrete orientation states (''domains'') characterized by a perpendicular alignment of the molecules with respect to the long axis of the pores and by a four-fold symmetry about this direction, which coincides with the crystalline symmetry of the Si host. A Bragg peak series characteristic of the formation of bilayers indicates a lamellar structure of the spatially confined alcohol crystals in 15 nm pores. By contrast, no layering reflections could be detected for 10 nm pores. The growth mechanism responsible for the peculiar orientation states is attributed to a nano-scale version of the Bridgman technique of single-crystal growth, where the dominant growth direction is aligned parallelly to the long pore axes. Our observations are analogous to the growth phenomenology encountered for medium length n-alkanes confined in mesoporous silicon (Phys. Rev. E 75, 021607 (2007)) and may further elucidate why porous silicon matrices act as an effective nucleation-inducing material for protein solution crystallization.Comment: 4 pages, 4 figures, to appear as a Brief Report in Physical Review

Structure and diffusion in amorphous aluminium silicate: A molecular dynamics computer simulation

The amorphous aluminium silicate (Al2O3)2(SiO2) [AS2] is investigated by means of large scale molecular dynamics computer simulations. We consider fully equilibrated melts in the temperature range 6100K >= T >= 2300K as well as glass configurations that were obtained from cooling runs from T=2300K to 300K with a cooling rate of about 10^12K/s. Already at temperatures as high as 4000K, most of the Al and Si atoms are four-fold coordinated by oxygen atoms. Thus, the structure of AS2 is that of a disordered tetrahedral network. The packing of AlO4 tetrahedra is very different from that of SiO4 tetrahedra in that Al is involved with a relatively high probability in small-membered rings and in triclusters in which an O atom is surrounded by four cations. We find as typical configurations two-membered rings with two Al atoms in which the shared O atoms form a tricluster. On larger length scales, the system shows a microphase separation in which the Al-rich network structure percolates through the SiO2 network. The latter structure gives rise to a prepeak in the static structure factor at a wavenumber q=0.5\AA^{-1}. The comparison of experimental X-ray data with the results from the simulation shows a good agreement for the structure function. The diffusion dynamics in AS2 is found to be much faster than in SiO2. We show that the self-diffusion constants for O and Al are very similar and that they are by a factor of 2-3 larger than the one for Si.Comment: 30 pages of Latex, 13 figure

Preferred orientation of n-hexane crystallized in silicon nanochannels: A combined x-ray diffraction and sorption isotherm study

We present an x-ray diffraction study on n-hexane in tubular silicon channels of approximately 10 nm diameter both as a function of the filling fraction f of the channels and as a function of temperature. Upon cooling, confined n-hexane crystallizes in a triclinic phase typical of the bulk crystalline state. However, the anisotropic spatial confinement leads to a preferred orientation of the confined crystallites, where the crystallographic direction coincides with the long axis of the channels. The magnitude of this preferred orientation increases with the filling fraction, which corroborates the assumption of a Bridgman-type crystallization process being responsible for the peculiar crystalline texture. This growth process predicts for a channel-like confinement an alignment of the fastest crystallization direction parallel to the long channel axis. It is expected to be increasingly effective with the length of solidifying liquid parcels and thus with increasing f. In fact, the fastest solidification front is expected to sweep over the full silicon nanochannel for f=1, in agreement with our observation of a practically perfect texture for entirely filled nanochannels

Yes-associated protein (YAP) is a negative regulator of chondrogenesis in mesenchymal stem cells

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Acknowledgements The authors would like to thank Dr Marius Sudol for the hYAP plasmids (obtained through Addgene), Dr Pete Zammit for the pMSCV-IRES-eGFP plasmid, Dr Robert Judson for subcloning the hYAP cDNAs into the pMSCV-IRES-eGFP plasmid, Dr Lynda Erskine for the provision of mouse embryo samples, and Professor Jimmy Hutchison and the Orthopaedics Department at the Aberdeen Royal Infirmary for the provision of human tissue samples. The authors are also grateful to Denise Tosh and Susan Clark for excellent technical support. This work was funded by Arthritis Research UK (grant 19429).Peer reviewedPublisher PD

White-light OLEDs using liquid crystal polymer networks

We have mixed nematic light-emitting liquid crystals and incorporated them as insoluble cross-linked polymer networks in a liquid crystal white-light organic light-emitting diode (LC-WOLED). The light emission is not voltage-dependent and polarized white light emission is also demonstrated. This wet-chemistry approach to WOLEDs is compatible with patterning by photolithography as well as by inkjet printing at room temperature on plastic substrates by roll-to-roll manufacturing

Advertising Effect on Consumer Emotions, Judgements, and Purchase Intent

Advertising has been found to induce consumer reactions, including emotions and judgements, which in turn are believed to relate to important outcomes, such as purchase intents. Marketing researches seek to understand these consumer reactions and their decision-making processes to influence purchase intents. This study focuses on the information role of emotion in understanding advertising effects and influencing consumer choices. Individuals use affective responses to evaluate information and to form judgements, which are critical in the decision-making process. This research further expands the Informative Strategy Model by adding judgement as a mediator. The results of a multiple mediation analysis provide support that consumers’ positive emotions directly influence their purchase intent, while consumer judgements partially mediate the effect of individuals’ emotions on purchase intents. Research findings benefit marketing and advertising professionals by providing empirical evidence for the effect of advertising, including controversial advertising on consumer purchase intent. The challenge with controversial advertising is that if individuals experience negative emotions and judgements, advertisers may have limited or potentially negative influence on consumer purchase intents

Negative Social Cognitions in Socially Anxious Youth: Distorted Reality or a Kernel of Truth?

We review studies that investigate negative social cognitions of socially anxious youth in relation to two specific domains: interpretation of ambiguous social situations and self-evaluation of social performance, including social skills and nervous behaviors. In this review, we address the question whether socially anxious youth’s negative perceptions are distortions of reality or reflect a kernel of truth as compared to other sources of information including independent adult observers and age peers. Studies key to this question are those that investigate not only the social perceptions themselves but also the social behavior of socially anxious youth. Hence the selection of studies for the review was based on this criterion. From the relevant literature it is, as yet, unclear whether the negative interpretations of ambiguous social situations shown by socially anxious youth are distorted or a reflection of reality. Socially anxious youth’s self-evaluations of social skills appear partly distorted and partly true, depending on the person judging the social skills. In contrast, self-evaluations of nervous behaviors appear distorted. The studies reviewed indicate that research would benefit from including a wider range of perceptions from persons relevant to the socially anxious youth’s daily social environment, not only parents and teachers but also their age peers

Emergence of a Dynamic Super-Structural Order Integrating Antiferroelectric and Antiferrodistortive Competing Instabilities in EuTiO3

Microscopic structural instabilities of EuTiO3 single crystal were investigated by synchrotron x-ray diffraction. Antiferrodistortive (AFD) oxygen octahedral rotational order was observed alongside Ti derived antiferroelectric (AFE) distortions. The competition between the two instabilities is reconciled through a cooperatively modulated structure allowing both to coexist. The electric and magnetic field effect on the modulated AFD order shows that the origin of large magnetoelectric coupling is based upon the dynamic equilibrium between the AFD - antiferromagnetic interactions versus the electric polarization - ferromagnetic interactions