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The CoSAXS beamline at the MAX IV Laboratory is a modern multi‐purpose (coherent) small‐angle X‐ray scattering (CoSAXS) instrument, designed to provide intense and optionally coherent illumination at the sample position, enabling coherent imaging and speckle contrast techniques. X‐ray tracing simulations used to design the beamline optics have predicted a total photon flux of 1012–1013 photons s−1 and a degree of coherence of up to 10% at 7.1 keV. The normalized degree of coherence and the coherent flux of this instrument were experimentally determined using the separability of a ptychographic reconstruction into multiple mutually incoherent modes and thus the Coherence in the name CoSAXS was verified. How the beamline can be used both for coherent imaging and XPCS measurements, which both heavily rely on the degree of coherence of the beam, was demonstrated. These results are the first experimental quantification of coherence properties in a SAXS instrument at a fourth‐generation synchrotron light source. [ABSTRACT FROM AUTHOR]

The temperature-dependent rheological behaviors of five selected binary eutectic mixture sugar alcohols, with great potential for latent heat storage in the range of 353.15 K to 523.15 K, were investigated. It was found that the rheological behaviors of the mixture sugar alcohols depend on those of the pure compounds as well as their molar ratios. The two mixtures of xylitol (75 mol%)+erythritol and erythritol (84 mol%)+d-mannitol behave like pseudoplastic fluids with typical non-Newtonian shear-thinning behaviors, as indicated by the power law index of 0.99 (<1). The mixture of d-mannitol (70 mol%)+d-dulcitol is a nonlinear Bingham fluid, exhibiting a slight yield stress (0.001 Pa to 0.01 Pa) at low shear rates. The rest two mixtures containing the cyclic-structured inositol behave like Herschel-Bulkley fluids. The infinite shear viscosities of the eutectic mixtures over the entire temperature range appear to be higher than those of their respective pure compounds, except for inositol. The mixture of xylitol (75 mol%)+erythritol at its melting point shows higher dynamic viscosity of about 0.546 Pa·s than the values of about 0.396 Pa·s and 0.035 Pa·s for xylitol and erythritol, respectively. In addition, the activation energies of viscous flow of the mixtures, as determined by fitting the dynamic viscosity-temperature curves using the Arrhenius model, also exhibit higher values than those of their pure compounds. The activation energy of viscous flow of the mixture xylitol (75 mol%)+erythritol was determined to be about 92 400 J/mol in the supercooled liquid state, while the supercooled liquid xylitol and erythritol have much lower values of 83 500 J/mol and 51 900 J/mol, respectively. Both the increased dynamic viscosities and activation energies of viscous flow can result in deteriorated crystallization performance during latent heat retrieval. [ABSTRACT FROM AUTHOR]

Imbalance in the metabolic pathway linking excitatory and inhibitory neurotransmission has been implicated in multiple psychiatric and neurologic disorders. Recently, we described enantiomer‐specific effects of 2‐methylglutamate, which is not decarboxylated to the corresponding methyl analogue of gamma‐aminobutyric acid (GABA): 4‐aminopentanoic acid (4APA). Here, we tested the hypothesis that 4APA also has enantiomer‐specific actions in brain. Mouse cerebral synaptosome uptake (nmol/mg protein over 30 min) of (R)‐4APA or (S)‐4APA was time and temperature dependent; however, the R enantiomer had greater uptake, reduction of endogenous GABA concentration, and release following membrane depolarization than did the S enantiomer. (S)‐4APA exhibited some weak agonist (GABAA α4β3δ, GABAA α5β2γ2, and GABAB B1/B2) and antagonist (GABAA α6β2γ2) activity while (R)‐4APA showed weak agonist activity only with GABAA α5β2γ2. Both 4APA enantiomers (100 mg/kg IP) were detected in mouse brain 10 min after injection, and by 1 hr had reached concentrations that were stable over 6 hr; both enantiomers were cleared rapidly from mouse serum over 6 hr. Two‐month‐old mice had no mortality following 100–900 mg/kg IP of each 4APA enantiomer but did have similar dose‐dependent reduction in distance moved in a novel cage. Neither enantiomer at 30 or 100 mg/kg impacted outcomes in 23 measures of well‐being, activity chamber, or withdrawal from hot plate. Our results suggest that enantiomers of 4APA are active in mouse brain, and that (R)‐4APA may act as a novel false neurotransmitter of GABA. Future work will focus on disease models and on possible applications as neuroimaging agents. [ABSTRACT FROM AUTHOR]

Foodborne illness ranks seventh globally among major health hazards, falling between air pollution and tuberculosis. Yet food safety is relatively understudied by economists. This paper provides an introduction to food safety for economists new to the subject. It presents an overview of the problem, the history of major policy reforms, and the structure of food safety governance in the United States and internationally. It identifies potential opportunities for economists in interdisciplinary food safety research and presents one example of this kind of collaboration, namely research focused on identifying the food sources of US Campylobacter infections. JEL CLASSIFICATION: I1; Q17; Q18 [ABSTRACT FROM AUTHOR]

Sinking particles and swimming plankton may deform ambient chemical gradients, leaving long trails of chemical disturbance that dissipate on a diffusive timescale. Imaging this phenomenon in a laboratory setting requires a large field of view, a broad depth of field, and a passive chemical substance that does not influence the hydrodynamics. These requirements obviate the use of traditional schlieren optical systems, which rely on density stratification and their consequent buoyancy forces, and modern planar laser‐induced fluorescence, which has a narrow depth of field. Further, the light used to induce plankton movement must be kept separate from the recorded signal. Here, we describe a new ultraviolet "dyegraph" technique that quantifies dye disturbance caused by sinking spheres and swimming zooplankton. An experimental tank is filled with seawater and a gradient of an ultraviolet‐absorbing pigment. Using modified shadowgraph optics, ultraviolet light spreads from a pinhole to a collimating lens, passes through the tank to a telecentric lens, and is recorded by a camera fitted with an ultraviolet bandpass filter. The dye is transparent in visible light but appears dark in the imaging system. The 3D chemical disturbance is reconstructed from images using tomographic inversion. After outlining the method, we present examples of chemical deformation trails generated by sinking spheres and live, swimming copepods. [ABSTRACT FROM AUTHOR]

The amide functionality is one of the most important and widely used groups in nature and in medicinal and industrial chemistry. Because of its importance and as the actual synthetic methods suffer from major drawbacks, such as the use of a stoichiometric amount of an activating agent, epimerization and low atom economy, the development of new and efficient amide bond forming reactions is needed. A number of greener and more effective strategies have been studied and developed. The transamidation of primary amides is particularly attractive in terms of atom economy and as ammonia is the single byproduct. This review summarizes the advancements in metal-catalyzed and organocatalyzed transamidation methods. Lewis and Brønsted acid transamidation catalysts are reviewed as a separate group. The activation of primary amides by promoter, as well as catalyst- and promoter-free protocols, are also described. The proposed mechanisms and key intermediates of the depicted transamidation reactions are shown. 1 Introduction 2 Metal-Catalyzed Transamidations 3 Organocatalyzed Transamidations 4 Lewis and Brønsted Acid Catalysis 5 Promoted Transamidation of Primary Amides 6 Catalyst- and Promoter-Free Protocols 7 Conclusion [ABSTRACT FROM AUTHOR]

This article offers a review of the literature on transnational labor regimes and statelessness to pursue further theorization from East and Southeast Asian contexts. The main focus is on how local norms (local sense of belonging, local moral code, and local hierarchies) are entangled with national‐level citizenship regimes to legitimate the discrimination of certain people to be statelessness and secure low‐wage migrant workers for the new global labor regime. First, traditional literature on citizenship and statelessness was reviewed; binary theoretical frameworks (including citizens/excluding non‐citizens) based on political recognition were indicated as the main limitations. Second, recent theories arguing for an intersection between national citizenship regimes and a new global labor regime were reviewed. Third, recent theories that illuminate the importance of local contexts in determining citizens' rights were reviewed based on formal exclusion and informal inclusion as well as formal inclusion and informal exclusion. Finally, it was concluded that further theorization is needed on how citizenship regimes and local norms intersect to produce statelessness, securing low‐wage migrant workers for the global labor regime through the global assemblages approach. Through the paper, East and Southeast Asia were illuminated as potentially fruitful research sites for further theorization on the topic. [ABSTRACT FROM AUTHOR]

The densities of aqueous solutions of acetamide up to a mole fraction of x2 = 0.3875 are measured over a wide range of temperatures (274.15–333.15) K at atmospheric pressure. The partial molar volumes of water and acetamide, the partial molar isobaric expansivities of the components, and the limiting partial properties of acetamide in water are calculated. The shift in the temperature of the maximum density of water at low temperatures is calculated. The results are discussed in terms of solute–solvent and solute–solute interactions. [ABSTRACT FROM AUTHOR]

Inferable from the significance of solvent mixtures in practical chemistry, toluene (TL) and butanol (BL) mixtures are used to studyfluorescence behavior of boronic acid dye 2-methoxy-5-fluoro-phenyl boronic acid (2MEFPBA). At the inception, preferential solvation is examined in TL-BL, to understand specific and nonspecific interactions. Suppan's dielectric enrichment model is further used to understand the nonideality and dielectric enrichment in TL-BL mixtures for preferential solvation. Bimolecular quenching reaction studies of 2MEFPBA with aniline as quencher are made in mixtures of TL-BLto know the effect of viscosity and dielectric constant variation at room temperature. The quenching process is studied in all solvent mixtures by steady state and transient state method. Quenching is characterized by S-V plots having upward curvature. Analysis of modified S-V equations which accounts both static and dynamic quenching allows calculating bimolecular quenching rate constant. The bimolecular quenching reactions are found to be significantly larger. Further finite sink approximation model is invoked so as to check whether reactions are diffusion limited. The extents of these rate parameters demonstrate that positive deviations in the Stern-Volmer (S-V) plot are because of the presence of apparent static and dynamic quenching process. [ABSTRACT FROM AUTHOR]

A phenomenological theory of diffusion and cross-diffusion of tracer particles in concentrated hard-sphere suspensions is developed. Expressions for the diffusion coefficients as functions of the host particle volume fraction are obtained up to the close-packing limit. In concentrated systems the tracer diffusivity decreases because of the reduced pore space available for diffusion. The tracer diffusivity can be modelled by a Stokes–Einstein equation with an effective viscosity that depends on the pore size. Tracer diffusion and segregation during sedimentation cease at a critical trapping volume fraction corresponding to a tracer glass transition. The tracer cross-diffusion coefficient, however, increases near the glass transition and diverges in the close-packed limit. [ABSTRACT FROM AUTHOR]

The mass transfer of substrates through a bio-catalytic membrane layer is a key issue in determining the performance of β-galactosidase-catalyzed conversion of lactose in a hollow fiber membrane reactor (HFMR) system. An investigation on the effect of solutes mass transfer through a bio-catalytic membrane layer was carried out using the coupled mass transfer-reaction model. Product formation was reduced at a trans-membrane pressure (TMP) of higher than 0.5 bar. Meanwhile, the concentration polarization modulus of solutes rapidly increased with higher TMP and this result suggests the formation of gel layer, which reduced bio-catalysis rate at higher applied TMP. The concentration profile of solutes or substrates on the bio-catalytic membrane surface, which determines the rate of reaction was reduced due to mass transfer limitation. This investigation highlights that the formation of substrate-β-gal complex in an immobilized system is influenced by the mass transfer behavior of its substrate. [ABSTRACT FROM AUTHOR]

The aim of this study is to examine the role that citizen perceptions of value congruence with public administrators can play in how we measure and evaluate public service integrity, as well as the extent to which such perceptions are associated with how citizens assess the quality of governance. Along those lines, this article reports the results of a pilot study that utilized an original survey, the Citizen-Administrator Value Congruence Survey, in order to measure citizen perceptions of public service value congruence with police officers and examine whether these perceptions are associated with how citizens assess the quality of governance. The findings suggest that perceived value congruence between citizens and police officers is associated with a number of important quality of governance indicators, including increased levels of citizen trust; perceptions of legitimacy; effective communication; positive relationships; and the ability of police officers to advance the public interest. [ABSTRACT FROM AUTHOR]

Nonequilibrium molecular dynamics (NEMD) simulations have provided unique insights into the nanoscale behaviour of lubricants under shear. This review discusses the early history of NEMD and its progression from a tool to corroborate theories of the liquid state, to an instrument that can directly evaluate important fluid properties, towards a potential design tool in tribology. The key methodological advances which have allowed this evolution are also highlighted. This is followed by a summary of bulk and confined NEMD simulations of liquid lubricants and lubricant additives, as they have progressed from simple atomic fluids to ever more complex, realistic molecules. The future outlook of NEMD in tribology, including the inclusion of chemical reactivity for additives, and coupling to continuum methods for large systems, is also briefly discussed. [ABSTRACT FROM AUTHOR]

The stability and rheological behavior of oil-in-water (O/W) nano-emulsions formed with a blend of Span20-Tween20 have been studied with and without diutan microbial polysaccharide. It is found that there exist thresholds for the water content and emulsifier to obtain stable nano-emulsions using the emulsion inversion phase (EIP) method. The viscosity of the nano-emulsion is proportional to the emulsifier content and inversely proportional to the water content. High emulsifier content is not conducive to the thermal stability of the nano-emulsion. The addition of diutan gum with negative charge into the nano-emulsions increases the electrostatic repulsion between droplets and makes the droplet size smaller and more unifom, slowing down the coalescence and Ostwald ripening of the nano-emulsions. Due to the association of the diutan gum double helix, a three-dimensional network structure is formed in the continuous phase of nano-emulsions, which improves the stability of nano-emulsions and is also the main factor giving the nano-emulsion high viscoelasticity at high temperature. This study offers new insight into the nano-emulsion containing microbial polysaccharide and may serve as a guideline for practical applications of new nano-emulsion systems. [ABSTRACT FROM AUTHOR]

Abstract: The systematic study presented addresses the need to understand the co‐crystallization of beet and cane material better. This is important because of the sugar market liberalization in 2017. Here the effect of crystal growth velocity on final sugar quality is investigated. Comparing three different thermal setups, studying different cane and beet mixtures color inclusion into sucrose crystals was analyzed. Within one thermal setup supersaturation was practically constant. Almost exclusively the time necessary to complete the crystallization at 50% solids level changed. Particle size and distribution remained unchanged. Hence, only the growth velocity varied. Growth rate appears to influence color inclusion less than mixing of beet and cane syrups. In cane syrups the relative color inclusion is the highest and most sensitive to growth velocities. Admixing only 33% of beet syrup, already changes this pattern dramatically and the color transfer factor is more than halved. This effect of beet material is most prominent for the mechanism liquid inclusion but also significant for co‐crystallization of colorants. This observation is possibly due to the different nature of the colorants originating from beet and cane. The findings provide a framework to optimize the space‐time yield under consideration of highest sugar quality to manufacturers. Practical applications: Co‐production of beet and cane is a promising opportunity to increase competitiveness by increasing utilization of equipment in the seasonal sugar industry. To do so reliably, quality parameters have to be met. The main problem to be solved is the control of white sugar color. Since cane and sugar beet deliver different coloring minor components, their interaction and respective inclusion mechanisms need to be understood. The work presented is part of a comprehensive study to elucidate this area of sugar processing that has not been studied yet. Next to the findings on inclusion characteristic and relative contribution of different mechanisms, the conclusions can directly be transferred into practice. The data gathered give a clear guidance to producers that higher inclusion levels of “colored” material, than current conservative practice dictates, can be tolerated due to the mutual suppression mechanism found. [ABSTRACT FROM AUTHOR]

The Air Stagnation Index (ASI) is a vital meteorological measure of the atmosphere's ability to dilute air pollutants. The original metric adopted by the US National Climatic Data Center (NCDC) is found to be not very suitable for China, because the decoupling between the upper and lower atmospheric layers results in a weak link between the near-surface air pollution and upper-air wind speed. Therefore, a new threshold for the ASI--Boundary-layer air Stagnation Index (BSI) is proposed, consisting of daily maximal ventilation in the atmospheric boundary layer, precipitation, and real latent instability. In the present study, the climatological features of the BSI are investigated. It shows that the spatial distribution of the BSI is similar to the ASI; that is, annual mean stagnations occur most often in the northwestern and southwestern basins, i.e., the Xinjiang and Sichuan basins (more than 180 days), and least over plateaus, i.e., the Qinghai--Tibet and Yunnan plateaus (less than 40 days). However, the seasonal cycle of the BSI is changed. Stagnation days under the new metric are observed to be maximal in winter and minimal in summer, which is positively correlated with the air pollution index (API) during 2000-2012. The correlations between the BSI and the concentration of fine particulate matter (PM2.5) during January 2013 and November to December in 2015-2017 of Beijing are also investigated. It shows that the BSI matches the day-by-day variation of PM2.5 concentration very well and is able to catch the haze episodes. [ABSTRACT FROM AUTHOR]

The partial molar volumes and isentropic compressions of aqueous solutions of tetrahydrofuran, tetrahydropyran, 1,4-dioxane, tetrahydropyran-2-methanol, 3-hydroxytetrahydrofuran, and tetrahydrofurfuryl alcohol were measured at 288.15, 298.15, and 313.15 K. Results are analyzed in terms of the effects of group addition to the molar volumes and isentropic compressions. The temperature dependence of the molar volumes and compressions, and their group contributions, are used to characterize changes in hydration. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease is a severe neurodegenerative disease characterized by the aggregation of amyloid-β peptide (Aβ) into toxic oligomers which activate microglia and astrocytes causing acute neuroinflammation. Multiple studies show that the soluble oligomers of Aβ42 are neurotoxic and proinflammatory, whereas the monomers and insoluble fibrils are relatively nontoxic. We show that Aβ42 aggregation is inhibited in vitro by oil palm phenolics (OPP), an aqueous extract from the oil palm tree (Elaeis guineensis). The data shows that OPP inhibits stacking of β-pleated sheets, which is essential for oligomerization. We demonstrate the inhibition of Aβ42 aggregation by (1) mass spectrometry; (2) Congo Red dye binding; (3) 2D-IR spectroscopy; (4) dynamic light scattering; (5) transmission electron microscopy; and (6) transgenic yeast rescue assay. In the yeast rescue assay, OPP significantly reduces the cytotoxicity of aggregating neuropeptides in yeast genetically engineered to overexpress these peptides. The data shows that OPP inhibits (1) the aggregation of Aβ into oligomers; (2) stacking of β-pleated sheets; and (3) fibrillar growth and coalescence. These inhibitory effects prevent the formation of neurotoxic oligomers and hold potential as a means to reduce neuroinflammation and neuronal death and thereby may play some role in the prevention or treatment of Alzheimer’s disease. [ABSTRACT FROM AUTHOR]

The various methods for studying polarities are based on the use of probe molecules, whose molecular spectral profile is significantly affected by the polarity of the medium. The absorption and emission spectra and dipole moments ( µ and µ ) of 2-(3-oxo-3H-benzo[f]chromen-1-ylmethoxy)-benzoic acid methyl ester (2BME) are studied in solvents of different polarities at room temperature. The determination of dipole moments by solvatochromic shift using various relations and the change in dipole moment (Δ µ) were determined using Stokes shift with the variation of the solvent polarity parameter ( E ). The value of µ greater than µ indicating that the probe is more polar in the higher state. DFT and TDDFT theoretical analysis of dipole moment in the vacuum and with solvent, solvent accessible surface (SAS) and molecular electrostatic potential (MEP) are also performed. [ABSTRACT FROM AUTHOR]

Surfactant films on solid surfaces have attracted much attention because of their scientific interest and applications, such as surface treatment agent, or for micro- or nano-scale templates for microfluidic devices. In this study, anionic surfactant sodium dodecyl sulfate (SDS) solutions with various charged inorganic salts was spread on a glass substrate and dried to form an SDS thin film. Atomic force microscopy (AFM) was employed to observe the micro-structure of the SDS thin film. The effects of inorganic salts on the morphology of the SDS film were observed and discussed. The results of experiments demonstrated that pure SDS film formed patterns of long, parallel, highly-ordered stripes. The existence of the inorganic salt disturbed the structure of the SDS film due to the interaction between the cationic ion and the anionic head groups of SDS. The divalent ion has greater electrostatic interaction with anionic head groups than that of the monovalent ion, and causes a gross change in the morphology of the SDS film. The height of the SDS bilayer measured was consistent with the theoretical value, and the addition of the large-sized monovalent ion would lead to lowering the height of the adsorbed structures. [ABSTRACT FROM AUTHOR]

Carbon nano-onion/surfactant (CNO/surfactant) composites offer the possibility to easily produce the soluble nanostructures. That approach combines the hydrophilicity of surfactants with the robustness of carbon structures to produce composites with superior and unusual physicochemical properties. We used the following surfactants: hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100), and polyethylene glycol sorbitan monolaurate (Tween 20) to non-covalently modify CNO surfaces. The existence of stable CNO composites are clearly evidenced by direct transmission electron microscopy observations, which are also supported by thermogravimetric analyses. Dynamic light scattering and zeta potential confirmed their dispersion and stability. Additionally, the biological activity of well-dispersed CNO/surfactant composites against a strain ofEscherichia coliwas assayed. In vitro antimicrobial assays for the composites revealed that only the CNO/CTAB composite decreased cell viability. This activity could be assigned to the simple composite dissociation in water solutions, however antimicrobial properties of the composite are slightly better when compared with pure CTAB. This indicate some synergic effect with respect to the properties of the pure surfactant. [ABSTRACT FROM AUTHOR]

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Presents a study which reported a systematic modification of thin YBa[sub2]Cu[sub3]O[suby] films with a scanning microscope. Function of the scanning tunneling microscope (STM); Benefits from the results on the surface structure of thin films; Techniques useful for the fabrication of nanoscale devices; Role of a STM system.

The relative viscosity coefficient $$ \left( {{\raise0.7ex\hbox{$\eta $} \!\mathord{\left/ {\vphantom {\eta {\eta_{0} }}}\right.\kern-0pt} \!\lower0.7ex\hbox{${\eta_{0} }$}}} \right) $$ and volumetric properties of mixtures of water with ethylene glycol (EG) and polyethylene glycols (PEGs) of molecular weights 400, 1000 and 4000 g·mol (PEG-400, PEG-1000 and PEG-4000) in the concentration range of ~0.01 to ~0.5 mol·kg, or up to 0.1 volume fraction ( $$ \phi_{2} $$ ), have been measured at three temperatures (293.15, 298.15 and 303.15 K) and at ambient pressure. The data were subjected to analysis by applications of the Jone-Dole equation, Vand's equation with the viscosity parameters B and D, particle interaction coefficients ( Q), Einstein-Simha factor ( $$ \nu $$ ), and hydration number ( h) were determined at different temperatures. Using the density data, the limiting apparent molar volumes ( $$ \phi_{\text{V}}^{0} $$ ) at different temperatures, and the limiting apparent molar expansivity ( $$ \phi_{\text{E}}^{0} $$ ) at 298.15 K, were obtained. Positive values of the viscosity B coefficients were observed for all the studied systems; these decrease with increase in temperature, while the D coefficients are also necessary to represent the data, showing specific behavior depending upon the chain length of the polymeric molecules. The larger viscosity increments in excess of the Einstein-Simha volume contributions, and decreasing hydration numbers with increasing temperature, are attributed to the water structure-making effect, solute-solvent hydrogen bond interaction and the presence of hydrophobic interaction between the chain segments of the polymeric molecules. The resulting D coefficients and the virial coefficients are examined from the point of view of solute-solute association. [ABSTRACT FROM AUTHOR]

A continuous Bucherer-Bergs hydantoin synthesis utilizing intensified conditions is reported. The methodology is characterized by a two-feed flow approach to independently feed the organic substrate and the aqueous reagent solution. The increased interfacial area of the biphasic reaction mixture and the lack of headspace enabled almost quantitative conversions within ca. 30 minutes at 120 °C and 20 bar even for unpolar starting materials. In addition, a selective N(3)-monoalkylation of the resulting heterocycles under batch microwave conditions is reported yielding potential acetylcholinesterase inhibitors. [ABSTRACT FROM AUTHOR]

Dimethylsulfide (DMS) is an important component of the global sulfur cycle and a source of carbon and sulfur in marine ecosystems. However, cellular concentrations of DMS (DMSc) have never been quantified, despite being essential to evaluating its physiological functions. Herein, we used NMR to determine the permeability for DMS across the cell membrane in Thalassiosira pseudonana. The experimentally determined permeability of DMS (2.18±0.27 cm s-1 at 300 K fell within the predicted permeability range for DMS (0.21-11.8 cm s-1) based on its octanol-water partition coefficient (18.6±1.1). Permeability was used with DMS fluxes to determine DMSc in three marine algal species. DMSc concentrations were <1 nmol [Lcell volume]-1, which is inconsistent with several proposed physiological functions for DMS. At nM levels, DMSc may serve as an infochemical or another unknown function. Our results demonstrate that DMS is highly permeable through the cell membrane; the phycosphere will control the DMS flux into the dissolved phase, and as such the DMSc determined here is likely applicable to a wide range of marine algae. Ultimately, the permeability of DMS constrains DMSc and its cellular function(s), which are important in assessing the role of this compound in marine waters. [ABSTRACT FROM AUTHOR]

The study of brain development in humans is limited by the lack of tissue samples and suitable in vitro models. Here, we model early human neural tube development using human embryonic stem cells cultured in a microfluidic device. The approach, named microfluidic-controlled stem cell regionalization (MiSTR), exposes pluripotent stem cells to signaling gradients that mimic developmental patterning. Using a WNT-activating gradient, we generated a neural tissue exhibiting progressive caudalization from forebrain to midbrain to hindbrain, including formation of isthmic organizer characteristics. Single-cell transcriptomics revealed that rostro-caudal organization was already established at 24 h of differentiation, and that the first markers of a neural-specific transcription program emerged in the rostral cells at 48 h. The transcriptomic hallmarks of rostro-caudal organization recapitulated gene expression patterns of the early rostro-caudal neural plate in mouse embryos. Thus, MiSTR will facilitate research on the factors and processes underlying rostro-caudal neural tube patterning.

Limiting partial molar volumes V of nine solutes [water, methanol, carbon disulfide, acetic acid, acetone, dimethyl sulfoxide, pyridine, benzene, and carbon tetrachloride] dissolved in various solvents have been measured using a pycnometer at 30.00 ± 0.05 °C. The V of water apparently decreases with increasing volume-% of void, i.e. empty space, in a solvent. From this result, we were able to experimentally demonstrate that small water molecules can easily enter into the voids existing in various solvents; however, the other larger solute molecules cannot enter easily into them. On the other hand, V of all the nine solutes increases with increasing mixing enthalpy, Δ H, for each solute (mole fraction after mixing x = 0.05) with various solvents. Generally, the repulsive solute-solvent interaction increases as Δ H increases. Therefore, we were able to experimentally demonstrate that V tends to increase with increasing repulsive solute-solvent interaction. It is considered that the repulsive interaction may lengthen the average neighboring solute-solvent distance and play an important role in affecting V as well as the void effect. [ABSTRACT FROM AUTHOR]