Local Collapse of a Monolayer on an Aqueous Subphase at a Fairly High Surface Pressure Lower than Its Collapsing Pressure Visualized by Electron Microscopy

1990 ◽  
Vol 19 (7) ◽  
pp. 1189-1192 ◽  
Author(s):  
Keiji Iriyama ◽  
Toshinari Araki
Keyword(s):  
Electron Microscopy ◽  
Surface Pressure ◽  
High Surface ◽  
Aqueous Subphase ◽  
High Surface Pressure

Physicochemical Characterization of Tetraether Lipids from Thermoplasma acidophilum. II. Film Balance Studies on the Monomolecular Organization of the Main Glycophospholipid in Monofilms

1985 ◽  
Vol 40 (3-4) ◽  
pp. 219-222 ◽  
Author(s):  
Christoph Strobl ◽  
Lambert Six ◽  
Klaus Heckmann ◽  
Birgit Henkel ◽  
Klaus Ring
Keyword(s):  
Surface Pressure ◽  
High Surface ◽  
Physicochemical Characterization ◽  
Thermoplasma Acidophilum ◽  
Alkyl Chains ◽  
Head Groups ◽  
Air Water Interface ◽  
Tetraether Lipids ◽  
High Surface Pressure

The bipolar main tetraether lipid (MPL) of Thermoplasma acidophilum has been shown to form typical liquid expanded films at the air-water interface. The limiting molecular area at the collaps pressure is approximately Ac=73 Å2 per molecule. Monopolar aiphytanyl diether lipids were found to occupy the same area at high surface pressure as MPL. Thus, it was concluded that in the monofilm only one of the two polar headgroups of the MPL molecules is hydrated, i.e. that the single MPL molecules arc oriented upright. The packing properties of MPT. in the monofilm are determined by the properties of the branched alkyl chains only; the polar head groups do not contribute to the space requirement in the film. The collaps pressure of the MPL film is approximately 39 mN m-1 at 8°C. At a surface pressure of π = 30 mN m-1 and 20 °C the film is stable for many hours.

scholarly journals DPPC Monolayers Exhibit an Additional Phase Transition at High Surface Pressure

2015 ◽  
Vol 108 (2) ◽  
pp. 85a
Author(s):  
Chen Shen ◽  
Jorge B. de la Serna ◽  
Bernd Struth ◽  
Beate Klösgen
Keyword(s):  
Phase Transition ◽  
Surface Pressure ◽  
High Surface ◽  
High Surface Pressure ◽  
Additional Phase

scholarly journals Synoptically Driven Arctic Winter States

2011 ◽  
Vol 24 (6) ◽  
pp. 1747-1762 ◽  
Author(s):  
Kirstie Stramler ◽  
Anthony D. Del Genio ◽  
William B. Rossow
Keyword(s):  
Heat Conduction ◽  
Sea Ice ◽  
Surface Temperature ◽  
Surface Pressure ◽  
High Surface ◽  
The Arctic ◽  
Interface Temperature ◽  
Baroclinic Wave ◽  
Pressure Phase ◽  
High Surface Pressure

Abstract The dense network of the Surface Heat Budget of the Arctic (SHEBA) observations is used to assess relationships between winter surface and atmospheric variables as the SHEBA site came under the influence of cyclonic and anticyclonic atmospheric circulation systems. Two distinct and preferred states of subsurface, surface, atmosphere, and clouds occur during the SHEBA winter, extending from the oceanic mixed layer through the troposphere and preceded by same-sign variations in the stratosphere. These states are apparent in distributions of surface temperature, sensible heat and longwave radiation fluxes, ocean heat conduction, cloud-base height and temperature, and in the atmospheric humidity and temperature structure. Surface and atmosphere are in radiative–turbulent–conductive near-equilibrium during a warm opaquely cloudy-sky state, which persists up to 10 days and usually occurs during the low surface pressure phase of a baroclinic wave, although occasionally occurs during the high surface pressure phase because of low, scattered clouds. Clouds occurring in this state have near-unity emissivity and the lowest bases in the vicinity of, or below, the temperature inversion peak. A cold radiatively clear-sky state persists up to two weeks, and occurs only in the high surface pressure phase of a baroclinic wave. The radiatively clear state has clouds that are too tenuous when surface based or, irrespective of opacity, located too far aloft to contribute significantly to the surface energy budget. There is a 13-K surface temperature difference between the two states, and atmospheric inversion peak temperatures are linearly related to the surface temperature in both states. The snow–sea ice interface temperature oscillates over the course of the winter season, as it cools during the radiatively clear state and is warmed from atmospheric emission above and ocean heat conduction from below during the opaquely cloudy state. Analysis of satellite data over the Arctic from 70°–90°N indicates that the radiatively clear and opaquely cloudy states observed at SHEBA may be representative of the entire Arctic basin. The results suggest that model formulation inadequacies should be easier to diagnose if modeled energy transfers are compared with observations using process-based metrics that acknowledge the bimodal nature of the Arctic ocean–ice–snow–atmosphere column, rather than monthly and regionally averaged quantities. Climate change projections of thinner Arctic sea ice and larger advective water vapor influxes into the Arctic could yield different frequencies of occupation of the radiatively clear and opaquely cloudy states and higher wintertime temperatures of SHEBA ocean, ice, snow, atmosphere, and clouds—in particular, a wintertime warming of the snow–sea ice interface temperature.

CONTROLLED AGGREGATION OF AZOBENZENE BASED ON DNA-MIMETICS AT THE AIR–WATER INTERFACE

2002 ◽  
Vol 01 (05n06) ◽  
pp. 597-601 ◽  
Author(s):  
KUNIHARU IJIRO ◽  
JIN MATSUMOTO ◽  
MITSUHIKO MORISUE ◽  
MASATSUGU SHIMOMURA
Keyword(s):  
Free Volume ◽  
Surface Pressure ◽  
Base Pair ◽  
High Surface ◽  
Pair Formation ◽  
Water Interface ◽  
Air Water Interface ◽  
Pressure Area ◽  
Azobenzene Chromophore ◽  
High Surface Pressure

Monolayers of thymine amphiphile containing azobenzene chromophore (Azo-Thy) were prepared on various aqueous oligonucleotide ( dA 30, d(GA) 15, d(GGA) 10) subphases. Pressure–area isotherms and reflection absorption spectra of the monolayers on dA 30 or d(GA) 15 solution showed that the H-aggregate of the azobenzene units was formed at higher surface pressure than 25 mN/m . In contrast, the monolayer on an aqueous d(GGA) 10 solution did not form any aggregates of the azobenzene units even at high surface pressure. Base-pair formation between Azo-Thy and template d(GGA) 10 could give free volume to the azobenzene units in the monolayer to prevent the aggregation of the azobenzene units at the air–water interface.

Electric-Line Milling Operation on Tree Master Valve of a High Surface Pressure Well Enables Well Control

2017 ◽  
Author(s):  
Mohammed D. Al-Ajmi ◽  
Raed A. Al-Ajlan ◽  
Nasser M. Al-Hajri ◽  
Hussain A. Al-Quwaisim ◽  
Saleh I. Zamka ◽  
...  
Keyword(s):  
Surface Pressure ◽  
High Surface ◽  
Well Control ◽  
Electric Line ◽  
Milling Operation ◽  
High Surface Pressure

scholarly journals Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction

2021 ◽  
Author(s):  
Ayat Nuri ◽  
Abolfazl Bezaatpour ◽  
Mandana Amiri ◽  
Nemanja Vucetic ◽  
Jyri-Pekka Mikkola ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
High Surface ◽  
High Surface Area ◽  
Coupling Reaction ◽  
Pd Nanoparticles ◽  
Significant Activity ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Ft Ir

AbstractMesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract

scholarly journals Synthesis and Optimization of Chitosan Nanoparticles Loaded with L-Ascorbic Acid and Thymoquinone

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 920 ◽  
Author(s):  
Nurhanisah Othman ◽  
Mas Masarudin ◽  
Cha Kuen ◽  
Nurul Dasuan ◽  
Luqman Abdullah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Infrared Spectroscopy ◽  
Encapsulation Efficiency ◽  
High Surface ◽  
Chitosan Nanoparticles ◽  
Polydispersity Index ◽  
Ionic Gelation ◽  
Surface Areas ◽  
Efficient Delivery

The combination of compounds with different classes (hydrophobic and hydrophilic characters) in single chitosan carrier is a challenge due to the hydrophilicity of chitosan. Utilization of l-ascorbic acid (LAA) and thymoquinone (TQ) compounds as effective antioxidants is marred by poor bioavailability and uptake. Nanoparticles (NPs) solved the problem by functioning as a carrier for them because they have high surface areas for more efficient delivery and uptake by cells. This research, therefore, synthesized chitosan NPs (CNPs) containing LAA and TQ, CNP-LAA-TQ via ionic gelation routes as the preparation is non-toxic. They were characterized using electron microscopy, zetasizer, UV–VIS spectrophotometry, and infrared spectroscopy. The optimum CNP-LAA-TQ size produced was 141.5 ± 7.8 nm, with a polydispersity index (PDI) of 0.207 ± 0.013. The encapsulation efficiency of CNP-LAA-TQ was 22.8 ± 3.2% for LAA and 35.6 ± 3.6% for TQ. Combined hydrophilic LAA and hydrophobic TQ proved that a myriad of highly efficacious compounds with poor systemic uptake could be encapsulated together in NP systems to increase their pharmaceutical efficiency, indirectly contributing to the advancement of medical and pharmaceutical sectors.

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