Effect of the Cationic Head Group on Cationic Surfactant-Based Surfactant Mediated Gelation (SMG)

The surfactant-mediated gelation (SMG) method allows us to formulate hydrogels using a water-insoluble organogelator. In this study, we formulated hydrogels using three cationic surfactants, hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride (CTAC), and hexadecylpyridinium chloride (CPC)] and an organogelator (12-hydroxyoctadecanoic acid (12-HOA), and studied their structures and mechanical properties. A fiber-like structure similar to that found in the 12-HOA-based organogels was observed by optical microscopy. Small- and wide-angle X-ray scattering profiles showed Bragg peaks derived from the long- and short-spacing of the crystalline structures in the gel fibers and a correlation peak from the surfactant micelles in the small-angle region. Furthermore, the formation of micelles in the hydrogels was confirmed by UV-vis spectroscopic measurements of the gel samples in the presence of Rhodamine 6G. We concluded that the hydrogels prepared by the SMG method in the present systems are orthogonal molecular assembled systems in which two different molecular assembled structures coexist. Among the three surfactant systems, the CTAB system presented the lowest critical gelation concentration and highest sol-gel transition temperature and viscoelasticity. These differences in gel fiber formation and gel properties were discussed from the viewpoint of the degree of solubilization of the gelator molecules in micelles coexisting with gel fibers and diffusion of the gelator molecules in the gel formation process.

The All-Sky SignAl Short-Spacing INterferometer (ASSASSIN) – I. Global-sky measurements with the Engineering Development Array-2

ABSTRACT Aiming to fill a crucial gap in our observational knowledge of the early Universe, experiments around the world continue to attempt to verify the claimed detection of the redshifted 21-cm signal from Cosmic Dawn by the EDGES experiment. This sky-averaged or ‘global’ signal from neutral hydrogen should be detectable at low radio frequencies (50–200 MHz), but is difficult to measure due to bright foreground emission and difficulties in reaching the required levels of instrumental-calibration precision. In this paper, we outline our progress toward using a novel new method to measure the global redshifted 21-cm signal. Motivated by the need to use alternative methods with very different systematic errors to EDGES for an independent result, we employ an array of closely spaced antennas to measure the global-sky signal interferometrically, rather than using the conventional approach with a single antenna. We use simulations to demonstrate our newly developed methods and show that, for an idealized instrument, a 21-cm signal could theoretically be extracted from the visibilities of an array of closely spaced dipoles. We verify that our signal-extraction methods work on real data using observations made with a Square-Kilometre-Array-like prototype, the Engineering Development Array-2. Finally, we use the lessons learned in both our simulations and observations to lay out a clear plan for future work, which will ultimately lead to a new global redshifted 21-cm instrument: the All-Sky SignAl Short-Spacing INterferometer (ASSASSIN).

Interplay among ATP-Dependent Chromatin Remodelers Determines Chromatin Organisation in Yeast

Cellular DNA is packaged into chromatin, which is composed of regularly-spaced nucleosomes with occasional gaps corresponding to active regulatory elements, such as promoters and enhancers, called nucleosome-depleted regions (NDRs). This chromatin organisation is primarily determined by the activities of a set of ATP-dependent remodeling enzymes that are capable of moving nucleosomes along DNA, or of evicting nucleosomes altogether. In yeast, the nucleosome-spacing enzymes are ISW1 (Imitation SWitch protein 1), Chromodomain-Helicase-DNA-binding (CHD)1, ISW2 (Imitation SWitch protein 2) and INOsitol-requiring 80 (INO80); the nucleosome eviction enzymes are the SWItching/Sucrose Non-Fermenting (SWI/SNF) family, the Remodeling the Structure of Chromatin (RSC) complexes and INO80. We discuss the contributions of each set of enzymes to chromatin organisation. ISW1 and CHD1 are the major spacing enzymes; loss of both enzymes results in major chromatin disruption, partly due to the appearance of close-packed di-nucleosomes. ISW1 and CHD1 compete to set nucleosome spacing on most genes. ISW1 is dominant, setting wild type spacing, whereas CHD1 sets short spacing and may dominate on highly-transcribed genes. We propose that the competing remodelers regulate spacing, which in turn controls the binding of linker histone (H1) and therefore the degree of chromatin folding. Thus, genes with long spacing bind more H1, resulting in increased chromatin compaction. RSC, SWI/SNF and INO80 are involved in NDR formation, either directly by nucleosome eviction or repositioning, or indirectly by affecting the size of the complex that resides in the NDR. The nature of this complex is controversial: some suggest that it is a RSC-bound “fragile nucleosome”, whereas we propose that it is a non-histone transcription complex. In either case, this complex appears to serve as a barrier to nucleosome formation, resulting in the formation of phased nucleosomal arrays on both sides.

Highly Efficient Nano-Porous Polysilicon Solar Absorption Films Prepared by Silver-Induced Etching

Nano-porous polysilicon high-temperature resistant solar absorption films were prepared by a thin layer of silver nanoparticles catalytic chemical etching. The polysilicon films with average tiny grain size of approximately 30 nm were obtained by high-temperature 800 °C furnace annealing of hydrogenated amorphous silicon films that were deposited on stainless substrate by plasma-enhanced chemical vapor deposition. The uniformly distributed 19 nm sized silver nanoparticles with 8 nm interspacing deposited on poly-Si film, were controlled by thin 4 nm thickness and very slow deposition rate 0.4 nm/min of thermal evaporation. Small silver nanoparticles with short spacing catalyzes the detouring etching process inducing the nano-porous textured surface with deep threaded pores. The etching follows the trail of the grain boundaries, and takes a highly curved thread like structure. The etching stops after reaching a depth of around 1100 nm, and the rest of the bulk thickness of the film remains mostly unaffected. The structure consists of three crystal orientations (111), (220), and (331) close to the surface. This crystalline nature diminishes gradually in the bulk of the film. High absorbance of 95% was obtained due to efficient light-trapping. Hence, preparation of nano-porous polysilicon films by this simple method can effectively increase solar absorption for the receiver of the solar thermal electricity Stirling Engine.

THE ROLE OF PROCEDURAL LEARNING ABILITY IN AUTOMATIZATION OF L2 MORPHOLOGY UNDER DIFFERENT LEARNING SCHEDULES

This paper reports on the reanalysis of Suzuki’s (2017) experiment and investigated the extent to which learning schedules influence automatization of second language (L2) morphology. Sixty participants were separated into two groups, which studied morphological rules for oral production under short-spacing (3.3-day intervals) and long-spacing learning conditions (7-day intervals). Their oral production test performance resulted in two measures of automatization: reaction time (RT) as an index of speedup and coefficient of variance (CV) as an index of stability/restructuring. The results showed that, while RT of both groups declined significantly after the training, the 3.3-day group exhibited greater propensity for restructuring than the 7-day group. Furthermore, procedural learning ability measured by the Tower of London task was significantly associated with RT, but not with CV, in the 3.3-day group only. These findings suggest that learning schedules and procedural learning ability influence different stages of automatization of L2 morphological learning.

Experimental Study on Aerodynamic Heating Induced by Dual Injections into Hypersonic Cross Flow

In this study, the distribution of surface heat transfer induced by dual side-jets injected into a hypersonic flow has been visualized using a temperature sensitive paint. The experiments were performed in both tandem and parallel injector arrangements, and the spacing between the injection holes was taken as a parameter in each arrangement. As a result, the aerodynamic heating in the separated region of the boundary layer and in the horseshoe vortex was clearly visualized. In the tandem arrangements, heat transfer remarkably increased immediately upstream of the front injector. The distributions and the intensity of surface heat transfer were similar to those caused by the single injection. On the other hand, in the parallel arrangements, the extent of the separation nearly doubled, and the maximum heat flux decreased to less than half of that from the single injection. The global distribution of heat transfer varied significantly as the injector spacing was changed. When the injectors were positioned with a large spacing, the interaction between the side-jets was relatively lowered, and thus distribution, as for the single injector, was induced around each injection hole individually. In contrast, with a short spacing, the dual injection behaved as a single obstacle. The most effective reduction of maximum heat flux was achieved with an intermediate injector spacing.

DOES STUDYING VOCABULARY IN SMALLER SETS INCREASE LEARNING?

The present study examined the effects of part and whole learning on the acquisition of second language (L2, English) vocabulary. In whole learning, the materials to be learned are repeated in one large block, whereas, in part learning, the materials are divided into smaller blocks and repeated. Experiment 1 compared the effects of the following three treatments: 20-item whole learning, four-item part learning, and 10-item part learning. Unlike previous studies, part and whole learning were matched in spacing. In Experiment 2, spacing as well as the part-whole learning distinction were manipulated, and the following three treatments were compared: 20-item whole learning, four-item part learning with short spacing, and four-item part learning with long spacing. Results of the two experiments suggest that, (a) as long as spacing is equivalent, the part-whole distinction has little effect on learning, and (b) spacing has a larger effect on learning than the part-whole distinction.

The Effect Of Age Distance of Birth to the Sibling Responses In 2-4 Years Old Children

Sibling response is competition in order to get love and care of one or both parents. The birth distance of a child is an important factor in the emergence of sibling response, because short spacing births of child tends to rise sibling negatif response. The puspose of this study was to identify the effect of age distance of birth to the sibling responses in 2-4 years old children. Method : Research design wascross sectional. Research sample was 26 respondent at BPS Mutiah Bendo Village Ponggok District of Blitar, at July 9th to July 20, 2012, its choosed with tota sampling. Data collected by using a structured interview and observation statements in the questionnaire. Analysis using T-Test, with ≤0.05 significant level. Result :The result showed that most of the respondents gave negativ responses for the short spacing of births, with p = 0,023. Discussion : There was an effect of space of birth with the sibling responses in children age of 2 – 4 years by 61,5% of the respondents, and sibling negative response in children age of 2 – 4 years by 71,4 % of the respondents.