Probing structural relaxation in complex fluids by critical fluctuations

Complex fluids, such as polymer solutions and blends, colloids and gels, are of growing interest in fundamental and applied soft-condensed-matter science. A common feature of all such systems is the presence of a mesoscopic structural length scale intermediate between atomic and macroscopic scales. This mesoscopic structure of complex fluids is often fragile and sensitive to external perturbations. Complex fluids are frequently viscoelastic (showing a combination of viscous and elastic behaviour) with their dynamic response depending on the time and length scales. Recently, non-invasive methods to infer the rheological response of complex fluids have gained popularity through the technique of microrheology, where the diffusion of probe spheres in a viscoelastic fluid is monitored with the aid of light scattering or microscopy. Here we propose an alternative to traditional microrheology that does not require doping of probe particles in the fluid (which can sometimes drastically alter the molecular environment). Instead, our proposed method makes use of the phenomenon of "avoided crossing" between modes associated with the structural relaxation and critical fluctuations that are spontaneously generated in the system.Comment: 4 pages, 4 figure

Acupuncture for stable angina pectoris: a systematic review protocol

Introduction Previous reviews indicate that the effect of acupuncture on stable angina pectoris (SAP) remains controversial. The results of trials published in the past 5 years may possibly change this situation, but an updated systematic review is not available. We therefore designed this study to systematically assess the efficacy and safety of acupuncture for treating SAP. Methods and analysis Nine online databases will be searched without language or publication status restrictions from their inception to September 2017. Randomised controlled trials that include patients with stable angina receiving acupuncture therapy versus a control group will be deemed eligible. The selection of studies, data extraction and risk of bias assessment will be carried out by two independent reviewers. Data synthesis will be performed using RevMan V.5.3 software with either a fixed effects model or random effects model, depending on the heterogeneity test. Evidence quality will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. The efficacy–effectiveness spectrum for each included trial will be rated using the Rating of Included Trials on the Efficacy-effectiveness Spectrum tool. Outcomes of interest include the improvement of weekly angina attacks and reduction of nitroglycerin medication use after receiving acupuncture treatment, the incidence of cardiovascular events, heart rate variability, pain intensity measured on a visual analogue scale, total workload and exercise duration at peak exercise, safety and adverse events. A meta-analysis will be conducted if no considerable heterogeneity is detected. The results will be presented as risk ratios with 95% CIs for dichotomous data and weighted mean differences or standardised mean differences with 95% CIs for continuous data. Ethics and dissemination This systematic review will not involve private information from individuals or endanger their rights, and therefore does not necessarily require ethical approval. The results may be published in a peer-reviewed journal or disseminated in relevant conferences. Trial registration number CRD42015016201.published_or_final_versio

Career Choice: A Case Study of College Students Shifting Career Paths

This study aimed to determine the causes, impacts, and varying perspectives of how two years of education can alter a person's ambitions. A qualitative research design, specifically the case study approach was used in this study. It focused on why the participants enrolled in a college program that was not aligned with their SHS Strand. The responses are subsequently transcribed and themes are identified. Students whose college courses do not correspond to their Senior High School strands have questioned their previous strand selection. This is due to difficulties they encountered as a result of the misalignment. According to the general findings, one of the most important factors to consider when choosing a career is one's interest. It was also evident within the data presented that the finances and practicality of the predetermined college courses that the students chose were weighed into their decision-making. It also shows that the majority of the participants agreed that their families have an impact on their career choices. The study also discovered that doing things that are not one's passion in the first place can be difficult, but it can help people challenge their abilities. The study concludes that indeed, pre-coaching strategies and guidance provided by schools play a large factor in students' awareness of their strengths and weaknesses. Also, setting goals may make the desired changes more difficult; however, the participants rediscovered their inclination and satisfaction with what they have pursued now, which motivated them to continue

The role of ancestral seascape discontinuity and geographical distance in structuring rockfish populations in the Pacific Northwest

Despite the apparent absence of physical barriers in the ocean to prevent dispersal, recent studies have highlighted the importance of biological, geographical, physical, and historical barriers in the genetic structuring of marine species populations. This representation is essential for the sustainable exploitation of natural marine resources and for the setup of efficient protected area networks for the conservation of marine species. In this study, we used extensive sampling of Sebastiscus marmoratus, a commercially important inshore rockfish with high site fidelity, to characterize their population genetic structure along the China–Japan coast and to determine the effect of past geological and current biological–physical barriers on the current genetic footprint. A 461-bp fragment of the mtDNA hypervariable portion control region was sequenced for 675 individuals from 15 geographical locations. A total of 292 haplotypes were identified. The population of S. marmoratus showed high haplotype and nucleotide diversity. Pairwise fixation index (FST) and analysis of molecular variance (AMOVA) revealed significant genetic differentiation among populations. The Bayesian skyline plots and neutrality statistics showed a sudden expansion of the S. marmoratus population around the Pleistocene. The Beibu Gulf group had the lowest mean number of pairwise differences, the lowest significant genetic differentiation, and the lowest haplotype and nucleotide diversity, and should be prioritized for protection in the future. Ocean currents, seascape discontinuity, geographical distance, and ecological characteristics may play an important role in shaping the contemporary phylogeographical patterns and population structures of S. marmoratus

Comparing glacial and Holocene opal fluxes in the Pacific sector of the Southern Ocean

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA2214, doi:10.1029/2008PA001693.The silicic acid leakage hypothesis (SALH) predicts that during glacial periods excess silicic acid was transported from the Southern Ocean to lower latitudes, which favored diatom production over coccolithophorid production and caused a drawdown of atmospheric CO2. Downcore records of 230Th-normalized opal (biogenic silica) fluxes from 31 cores in the Pacific sector of the Southern Ocean were used to compare diatom productivity during the last glacial period to that of the Holocene and to examine the evidence for increased glacial Si export to the tropics. Average glacial opal fluxes south of the modern Antarctic Polar Front (APF) were less than during the Holocene, while average glacial opal fluxes north of the APF were greater than during the Holocene. However, the magnitude of the increase north of the APF was not enough to offset decreased fluxes to the south, resulting in a decrease in opal burial in the Pacific sector of the Southern Ocean during the last glacial period, equivalent to approximately 15 Gt opal ka−1. This is consistent with the work of Chase et al. (2003a), and satisfies the primary requirement of the SALH, assuming that the upwelled supply of Si was approximately equivalent during the Holocene and the glacial period. However, previous results from the equatorial oceans are inconsistent with the other predictions of the SALH, namely that either the Corg:CaCO3 ratio or the rate of opal burial should have increased during glacial periods. We compare the magnitudes of changes in the Southern Ocean and the tropics and suggest that Si escaping the glacial Southern Ocean must have had an alternate destination, possibly the continental margins. There is currently insufficient data to test this hypothesis, but the existence of this sink and its potential impact on glacial pCO2 remain interesting topics for future study.Funding for this research was provided in part by the U.S. NSF (grant OPP02-30268). We thank the core repository at LDEO and the Antarctic Research Facility at FSU for providing samples

Side-by-Side In(OH)3 and In2O3 Nanotubes: Synthesis and Optical Properties

A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D) In(OH)3 nanostructures. By calcining the 1D In(OH)3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH)3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH)3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH)3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH)3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies

A nanocomposite ultraviolet photodetector based on interfacial trap-controlled charge injection

Ultraviolet photodetectors have applications in fields such as medicine, communications and defence1, and are typically made from single-crystalline silicon, silicon carbide or gallium nitride p–n junction photodiodes. However, such inorganic photodetectors are unsuitable for certain applications because of their high cost and low responsivity (<0.2 A W−1)2. Solution-processed photodetectors based on organic materials and/or nanomaterials could be significantly cheaper to manufacture, but their performance so far has been limited2,3,4,5,6,7. Here, we show that a solution-processed ultraviolet photodetector with a nanocomposite active layer composed of ZnO nanoparticles blended with semiconducting polymers can significantly outperform inorganic photodetectors. As a result of interfacial trap-controlled charge injection, the photodetector transitions from a photodiode with a rectifying Schottky contact in the dark, to a photoconductor with an ohmic contact under illumination, and therefore combines the low dark current of a photodiode and the high responsivity of a photoconductor (∼721–1,001 A W−1). Under a bias of <10 V, our device provides a detectivity of 3.4 × 1015 Jones at 360 nm at room temperature, which is two to three orders of magnitude higher than that of existing inorganic semiconductor ultraviolet photodetectors

Parametric Study on Dimensional Control of ZnO Nanowalls and Nanowires by Electrochemical Deposition

A simple electrochemical deposition technique is used to synthesize both two-dimensional (nanowall) and one-dimensional (nanowire) ZnO nanostructures on indium-tin-oxide-coated glass substrates at 70°C. By fine-tuning the deposition conditions, particularly the initial Zn(NO3)2·6H2O electrolyte concentration, the mean ledge thickness of the nanowalls (50–100 nm) and the average diameter of the nanowires (50–120 nm) can be easily varied. The KCl supporting electrolyte used in the electrodeposition also has a pronounced effect on the formation of the nanowalls, due to the adsorption of Cl− ions on the preferred (0001) growth plane of ZnO and thereby redirecting growth on the (100) and (20) planes. Furthermore, evolution from the formation of ZnO nanowalls to formation of nanowires is observed as the KCl concentration is reduced in the electrolyte. The crystalline properties and growth directions of the as-synthesized ZnO nanostructures are studied in details by glancing-incidence X-ray diffraction and transmission electron microscopy