Coarsening of Topological Defect Systems in Freely-Suspended Smectic-C Films

Mechanically quenching a smectic-C (SmC) liquid crystal film produces a dense array of topological defects in the film. These defects interact and annihilate in a process called `coarsening' which has been captured in high temporal resolution using depolarized reflected light microscopy. A convolutional neural network as well as a binary classification network are used to obtain the trajectories and topological charges of the defects in the film and the coarsening dynamics have been compared to results from theoretical as well as simulated studies. Subsequently, we model the quenched film as a system of charged interacting and diffusing charges, as well as simulate the $c$-director field in quenched SmC films using the XY model. Finally, the dynamics of a mutually annihilating pair of defects is considered and has been compared to results from theory as well as other experiments.</p

The Role of Intercultural Communication Competence in Business Collaboration to Develop Start Ups in the Global Era

In this global era, more and more startups are developing their businesses with partners from other regions or countries. However, intercultural cooperation that is not accompanied by intercultural communication competence will often create unresolved conflicts. This research is a qualitative study with a phenomenological approach. In this study, researchers wanted to dig up information about the experiences of informants in developing business partnerships and the difficulties encountered when communicating with business partners from different countries or regions. Data collection was carried out using unstructured interviews so that the informants could be more flexible in sharing their experiences when starting their business development. They can also tell freely about any cultural background conflicts that are often encountered when discussing or communicating with business partners from different cultures. In this study, researchers interviewed 10 informants consisting of start-up actors, who have been in business for more than 5 years and have collaborated with business partners from other regions or countries. This is to dig up information about their experiences when communicating with these business partners and to get data on what obstacles start-ups experience when collaborating with their business partners. The results of this study indicate that Intercultural Communication Competence (ICC), which consists of cognitive, affective and behavioral aspects, is needed by start-ups, especially if they want to develop their business by working with domestic and foreign partners. With the existence of ICC, start-up actors can avoid ethnocentrism, stereotypes and prejudice, as well as language barriers and differences in values

Developing a Multi-modal Listing Service for Real Estate Agency Practice in Nigeria

Fraudsters posing as real estate agents threaten the reputation of real estate agencies in Nigeria. These fraudsters have continually defrauded unsuspecting members of the public. The major cause of this lapse is due largely to the fact that there is no known platform provided in the country that allows members of the public to verify a given real estate agent. This paper aims to provide support to real estate agency practice in Nigeria by developing a multi-modal listing service for verifying registered real estate agents and to also provide information on real estates available for sale, lease or rent. The requirements for the system were gathered through observation, literature survey and user survey. These requirements were then modelled using the Unified Modelling Language (UML). The system is developed both as a web and mobile application using an open source content management system (WordPress). This paper essentially presents the: requirements gathering process, design and implementation of the multimodal listing service as well as how it compares with other similar services developed elsewhere. The multi-modal listing service developed in this study is a welcome development due to the availability and widespread adoption of the Internet and Internet-enabled mobile devices in Nigeria. The tool can be of use to the National Association of Estate Agents in Nigeria - a body saddled with the responsibility of rebranding the real estate agency profession in Nigeria

Topological defect coarsening in quenched smectic-C films analyzed using artificial neural networks

Mechanically quenching a thin film of smectic-C liquid crystal results in the formation of a dense array of thousands of topological defects in the director field. The subsequent rapid coarsening of the film texture by the mutual annihilation of defects of opposite sign has been captured using high-speed, polarized light video microscopy. The temporal evolution of the texture has been characterized using an object-detection convolutional neural network to determine the defect locations, and a binary classification network customized to evaluate the brush orientation dynamics around the defects in order to determine their topological signs. At early times following the quench, inherent limits on the spatial resolution result in undercounting of the defects and deviations from expected behavior. At intermediate to late times, the observed annihilation dynamics scale in agreement with theoretical predictions and simulations of the $2$D XY model.Comment: 11 pages, 10 figure

Adsorption of Amorphous Silica Nanoparticles onto Hydroxyapatite Surfaces Differentially Alters Surfaces Properties and Adhesion of Human Osteoblast Cells.

Silicon (Si) is suggested to be an important/essential nutrient for bone and connective tissue health. Silicon-substituted hydroxyapatite (Si-HA) has silicate ions incorporated into its lattice structure and was developed to improve attachment to bone and increase new bone formation. Here we investigated the direct adsorption of silicate species onto an HA coated surface as a cost effective method of incorporating silicon on to HA surfaces for improved implant osseointegration, and determined changes in surface characteristics and osteoblast cell adhesion. Plasma-sprayed HA-coated stainless steel discs were incubated in silica dispersions of different concentrations (0-42 mM Si), at neutral pH for 12 h. Adsorbed Si was confirmed by XPS analysis and quantified by ICP-OES analysis following release from the HA surface. Changes in surface characteristics were determined by AFM and measurement of surface wettability. Osteoblast cell adhesion was determined by vinculin plaque staining. Maximum Si adsorption to the HA coated disc occurred after incubation in the 6 mM silica dispersion and decreased progressively with higher silica concentrations, while no adsorption was observed with dispersions below 6 mM Si. Comparison of the Si dispersions that produced the highest and lowest Si adsorption to the HA surface, by TEM-based analysis, revealed an abundance of small amorphous nanosilica species (NSP) of ~1.5 nm in diameter in the 6 mM Si dispersion, with much fewer and larger NSP in the 42 mM Si dispersions. 29Si-NMR confirmed that the NSPs in the 6 mM silica dispersion were polymeric and similar in composition to the larger NSPs in the 42 mM Si dispersion, suggesting that the latter were aggregates of the former. Amorphous NSP adsorbed from the 6 mM dispersion on to a HA-coated disc surface increased the surface's water contact angle by 53°, whereas that adsorbed from the 42 mM dispersion decreased the contact angle by 18°, indicating increased and decreased hydrophobicity, respectively. AFM showed an increase in surface roughness of the 6 mM Si treated surface, which correlated well with an increase in number of vinculin plaques. These findings suggest that NSP of the right size (relative to charge) adsorb readily to the HA surface, changing the surface characteristics and, thus, improving osteoblast cell adhesion. This treatment provides a simple way to modify plasma-coated HA surfaces that may enable improved osseointegration of bone implants.The authors acknowledge the National Institute of Health Research (NIHR) and the Medical Research Council, grant number MC_US_A090_0008/Unit Programme number U1059, www. mrc.ac.uk, to RJ; Engineering and Physical Sciences Research Council (UK), grant number EP/ F019823/1 (https://www.epsrc.ac.uk) to PK, DJM; Engineering and Physical Sciences Research Council (UK), grant number EP/K023853/1 (https://www.epsrc.ac.uk) "Leeds EPSRC Nanoscience and Nanotechnology Research Equipment Facility (LENNF)" to APB and PK. Orthopaedic Research UK Grant "Drug Delivery of Silicon from the Furlong HA-C Hip" (www.oruk.org) to PK, RAB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pone.014478

A molecular assembly system for presentation of antigens on the surface of HBc virus-like particles

AbstractHepatitis B virus-like particles, icosahedral structures formed by multiple core protein dimers, are promising immune-enhancing vaccine carriers for foreign antigens. Insertions into the surface-exposed immunodominant loop are especially immunogenic. However, the need to conserve the particulate structure to ensure high immunogenicity imposes restraints on the nature of the heterologous sequence that can be inserted. We propose a new approach to constructing HBc particles linked to the target epitopes that relies on non-covalent interactions between the epitope and pre-assembled unmodified HBc particles. Interaction was enabled by fusion of the epitope to the GSLLGRMKGA peptide, binding to the spike tips. This peptide may be used as a “binding tag” allowing in vitro construction of HBc particles carrying the target peptide. Such virus-like particles carrying multiple copies of the extracellular domain of the M2 protein of different influenza strains appeared to be highly immunogenic and protected immunised mice against a lethal influenza challenge

Assessment of Olfactory Processing in Parkinson’s Disease Patients

Background: Hyposmia is an early symptom of Parkinson’s Disease (PD) that often predates motor symptoms by years. Hyposmia has been shown to have a more consistent link to idiopathic PD than to other movement disorders. Olfaction has the potential to be used as a biomarker for PD, either through clinical evaluation or imaging. Objectives: This study uses functional magnetic resonance imaging (fMRI) to assess differences in olfaction pathways between anosmic early PD patients and age and gender-matched controls. Methods: 12 PD patients and 12 age- and gender-matched control subjects were recruited from the subject panel of a previous UMMS study on olfaction and PD. All PD patients were determined to be anosmic, and all controls were determined to have normal olfaction for their age and gender. All subjects underwent fMRI including periods with and without odorant exposure. Statistical analysis was performed using SPM8, using a general linear model to calculate BOLD signal changes for each scent relative to room air. A random effect model was used to infer general population effects. Results: Control subjects showed significant activation in the piriform cortex, anterior olfactory nucleus, insula, hippocampus and temporal lobe, all regions associated with olfactory processing. Relative to control subjects, PD patients showed no significant BOLD activation in the olfactory pathways of the brain. In response to a citrus scent, PD patients showed activation in the superior and middle frontal lobe, as well as the cingulate gyrus. In response to a cinnamon scent, PD patients showed significant activation in the precuneus and paracentral lobule as well as lower levels of activation in the frontal lobe. PD patients showed no significant areas of activation in response to a mint scent. Conclusion: Our results suggest that anosmic PD patients do not show activation of the olfactory pathways in the brain on exposure to these odorants. Taken together with previous studies, this suggests that BOLD activation in these regions of the brain can reflect clinical olfactory capability. In addition, PD patients show areas of increased activation, particularly in the frontal lobe. These distinct patterns of BOLD activation allow us to consider the feasibility of fMRI as a biomarker for diagnosis and evaluation of PD