The surface properties of Alcohols containing sterically hindered Hydroxyl groups

1959 ◽  
Vol 12 (2) ◽  
pp. 166 ◽  
Author(s):  
gE Hibberd ◽  
AE Alexander
Keyword(s):  
Water Molecule ◽  
Surface Properties ◽  
The Other ◽  
Hydroxyl Groups ◽  
Surface Moment ◽  
Sterically Hindered ◽  
Long Chain

The surface properties of several alcohols containing sterically hindered hydroxyl groups have been studied. Tricyclohexyl carbinol formed monolayers having a surface moment considerably greater than that of long-chain alcohols. It is suggested that this is due to the virtual inaccessibility of the C-O bond to a water molecule. The collapse phenomenon of tricyclohexyl carbinol is quite different from that expected for a compound of m.p. 91-92 �C. It appears that the molecules collapse to form a lens or glass, rather than a crystal. 1,1,3,3-Tetraphenyl propanediol-1,3 gave monolayers of similar surface properties. The other compounds tested did not give films of measurable stability.

Crystal Structure of Calcium Picrate Pentahydrate: A New Eight-Coordinate Stereochemistry for [M(bidentate)2(unidentate)4]

1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Title Compound ◽  
Lattice Site ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Triangular Face ◽  
X Ray

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.

Salt effects on the surface properties of long-chain alkyl substituted crown compounds

1983 ◽  
Vol 92 (2) ◽  
pp. 463-468 ◽  
Author(s):  
Ping-Lin Kuo ◽  
Kikuo Tsuchiya ◽  
Isao Ikeda ◽  
Mitsuo Okahara
Keyword(s):  
Surface Properties ◽  
Crown Compounds ◽  
Salt Effects ◽  
Long Chain

Ligand Hyperfine Interaction in the Complex [Mn(H2O)6] ++ in La2(Mg,Mn)3(NO3)12·24H2O

1969 ◽  
Vol 24 (11) ◽  
pp. 1746-1751 ◽  
Author(s):  
D. van Ormondt ◽  
R. de Beer ◽  
M. Brouha ◽  
F. de Groot
Keyword(s):  
Simple Model ◽  
Water Molecule ◽  
Hyperfine Interaction ◽  
Principal Direction ◽  
The Other ◽  
Water Molecules ◽  
Manganese Ion ◽  
Interaction Tensor ◽  
Principal Directions

Abstract The elements of the hyperfine interaction (h.f.i.) between the manganese ion and the protons in the complex [Mn(H2O)6]++ in one of the two possible sites in La2(Mg, Mn)3(NO3)12 · 24 H2O have been measured with ENDOR at 15 to 20 K. The six water molecules in the complex at the chosen site are equivalent for reasons of symmetry.One principal direction of the h.f.i. tensor of each proton is found to be perpendicular to the Mn, O line. With the assumption that each proton is located in the plane of the other two principal directions of its interaction tensor the positions of the protons are evaluated from the anisotropic parts of the h.f.i. tensors. In this calculation the effect of covalency on the anisotropic h.f.i. is ac-counted for with the aid of a simple model.The isotropic h.f.i.'s with the two protons of a water molecule appear to be very nearly equal (+ 0.890 MHz for both). This latter result is remarkable in view of the fact that one proton is distinctly nearer to the manganese ion than the other.

scholarly journals Subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase in rat liver

1989 ◽  
Vol 257 (1) ◽  
pp. 221-229 ◽  
Author(s):  
L Schepers ◽  
M Casteels ◽  
K Verheyden ◽  
G Parmentier ◽  
S Asselberghs ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cholic Acid ◽  
Rat Liver ◽  
Subcellular Distribution ◽  
The Other ◽  
Acid Activation ◽  
Long Chain Fatty Acids ◽  
Microsomal Membranes ◽  
Triton X ◽  
Long Chain

The subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase were studied in rat liver and were compared with those of palmitoyl-CoA synthetase and choloyl-CoA synthetase. Trihydroxycoprostanoyl-CoA synthetase and choloyl-CoA synthetase were localized almost completely in the endoplasmic reticulum. A quantitatively insignificant part of trihydroxycoprostanoyl-CoA synthetase was perhaps present in mitochondria. Peroxisomes, which convert trihydroxycoprostanoyl-CoA into choloyl-CoA, were devoid of trihydroxycoprostanoyl-CoA synthetase. As already known, palmitoyl-CoA synthetase was distributed among mitochondria, peroxisomes and endoplasmic reticulum. Substrate- and cofactor- (ATP, CoASH) dependence of the three synthesis activities were also studied. Cholic acid and trihydroxycoprostanic acid did not inhibit palmitoyl-CoA synthetase; palmitate inhibited the other synthetases non-competitively. Likewise, cholic acid inhibited trihydroxycoprostanic acid activation non-competitively and vice versa. The pH curves of the synthetases did not coincide. Triton X-100 affected the activity of each of the synthetases differently. Trihydroxycoprostanoyl-CoA synthetase was less sensitive towards inhibition by pyrophosphate than choloyl-CoA synthetase. The synthetases could not be solubilized from microsomal membranes by treatment with 1 M-NaCl, but could be solubilized with Triton X-100 or Triton X-100 plus NaCl. The detergent-solubilized trihydroxycoprostanoyl-CoA synthetase could be separated from the solubilized choloyl-CoA synthetase and palmitoyl-CoA synthetase by affinity chromatograpy on Sepharose to which trihydroxycoprostanic acid was bound. Choloyl-CoA synthetase and trihydroxycoprostanoyl-CoA synthetase could not be detected in homogenates from kidney or intestinal mucosa. The results indicate that long-chain fatty acids, cholic acid and trihydroxycoprostanic acid are activated by three separate enzymes.

Comparison of Four Surfactants: In Vitro Surface Properties and Responses of Preterm Lambs to Treatment at Birth

PEDIATRICS ◽  
1987 ◽  
Vol 79 (1) ◽  
pp. 38-46
Author(s):  
Machiko Ikegami ◽  
Yotaro Agata ◽  
Tarek Elkady ◽  
Mikko Hallman ◽  
David Berry ◽  
...  
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Surface Adsorption ◽  
Soluble Proteins ◽  
The Other ◽  
Clinical Responses ◽  
Spreading Rates ◽  
Surface Spreading

Natural sheep surfactant, rabbit surfactant, human surfactant, and surfactant TA were compared for in vitro surface properties and for responses of preterm lambs to treatment. Equivalent amounts of sheep, rabbit, and human surfactants were needed to lower the surface tension to less than 10 dynes/cm, whereas four times less surfactant TA similarly lowered the surface tension. Surface-spreading rates were similar for the surfactants. The surface adsorption of the batch of human surfactant tested was much slower than was adsorption of the other surfactants. Ventilation was significantly improved in all surfactant-treated lambs relative to the control lambs, indicating the general efficacy of the surfactant treatments. Overall, surfactant TA had the best in vitro characteristics, yet the preterm lambs treated at birth with surfactant TA had lower Po2 values and higher ventilatory requirements than did the sheep surfactant-treated lambs. The in vivo responses to rabbit surfactant were intermediate between the responses to sheep surfactant and to surfactant TA. Human surfactant resulted in the least effective clinical response. More of the phosphatidylcholine associated with human surfactant and surfactant TA was lost from the alveoli and lung tissue after four hours of ventilation than was lost from sheep or rabbit surfactant-treated lambs. More intravascular radiolabeled albumin leaked into the alveoli of the surfactant TA-treated lambs than sheep or rabbit surfactant-treated. lambs. The four surfactants also had different sensitivities to the effects on minimum surface tensions of the soluble proteins present in alveolar washes. The study demonstrates that the range of clinical responses was not predictable based on the in vitro surface properties that we measured. The surfactants behaved differently with respect to loss from the lungs and sensitivity to soluble proteins. Factors other than surface properties are important for the in vivo responses to surfactant treatments.

Effects of Long-Chain Non-Coding Ribonucleic Acid Hox Tran Antisense RNA on Proliferation and Migration of Epithelial Cells of Cataract Lens

2021 ◽  
Vol 11 (12) ◽  
pp. 2329-2336
Author(s):  
Qiang Zeng ◽  
Yiting Luo
Keyword(s):  
Epithelial Cells ◽  
Ribonucleic Acid ◽  
Transforming Growth Factor ◽  
Colorimetric Method ◽  
The Other ◽  
Human Lens ◽  
And Migration ◽  
Long Chain ◽  
Proliferation And Migration ◽  
E Cadherin

In order to explore effects of long-chain non-coding ribonucleic acid (RNA) HOTAIR on proliferation and migration of human lens epithelial cells, SRA01/04 cells were selected as the research strain in this study and divided into S1 group (no HOTAIR transfection), S2 group (siHOTAIR transfection), S3 group (siHOTAIR+10 ng/mL TGF-β2), and S4 group (no HOTAIR transfection+10 ng/mL TGF-β2) according to the presence or absence of transforming growth factor (TGF)-β2 and silent HOTAIR treatment. 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) colorimetric method was applied to detect cell proliferation.Western blot was used for detection of E-cadherin, zonula occluden-1 (ZO-1), Vimentin, α-smooth muscle actin (SMA), Snail, Slug, zinc finger E-box binding homeobox 1 (ZEB1), and Smad-2 expressions. Results showed that the number of transmembrane cells in S4 group was higher markedly than that of the other groups, but that of S2 group dropped steeply compared with the other groups (P <0.05); E-cadherin (2.59±0.58) and ZO-1 (1.95±0.56) of S2 group increased hugely compared with the other groups, while Vimentin (0.57±0.14) and α-SMA (0.64±0.28) decreased sharply compared with the other groups (P < 0.05); Snail (2.51±0.59), Slug (2.11±0.47), and ZEB1 (2.83±0.53) of S4 group rose obviously compared with the other groups, but the above of S2 group reduced hugely compared with the other groups (P < 0.05); pSmad-2 and pSmad-3 of S4 group elevated greatly compared with the other groups, and those of S2 group reduced hugely compared with the other groups (P < 0.05). In conclusion, HOTAIR high expression could promote TGF-β2-induced SRA01/04 cell proliferation, migration, invasion, and epithelial-mesenchymal trans-differentiation, which was related to TGF-β/Smad signaling pathway.

Flexural Properties and Polished Surface Characteristics of a Structural Colored Resin Composite

2021 ◽  
Author(s):  
K Mizutani ◽  
R Ishii ◽  
T Takamizawa ◽  
S Shibasaki ◽  
H Kurokawa ◽  
...  
Keyword(s):  
Surface Properties ◽  
Resin Composite ◽  
Surface Characteristics ◽  
The Other ◽  
Polished Surface ◽  
Flexural Properties ◽  
Strong Positive Correlation ◽  
Resin Composites ◽  
Diamond Bur ◽  
Flexible Disk

SUMMARY Objective: The aim of this study was to determine the flexural properties and surface characteristics of a structural colored resin composite after different finishing and polishing methods, in comparison to those of conventional resin composites. Methods and Materials: A structural color resin composite, Omnichroma (OM, Tokuyama Corp, Chiyoda City, Tokyo, Japan), and two comparison resin composites, Filtek Supreme Ultra (FS, 3M, St Paul, MN, USA) and Tetric EvoCeram (TE, Ivoclar Vivadent, Schaan, Liechtenstein), were used. The flexural properties of the resin composites were determined in accordance with the ISO 4049 specifications. For surface properties, 70 polymerized specimens of each resin composite were prepared and divided into seven groups of 10. Surface roughness (Sa), gloss (GU), and surface free energy (SFE) were investigated after the following finishing and polishing methods. Three groups of specimens were finished with a superfine-grit diamond bur (SFD), and three with a tungsten carbide bur (TCB). After finishing, one of the two remaining groups was polished with a one-step silicone point (CMP), and the other with an aluminum oxide flexible disk (SSD). A group ground with SiC 320-grit was set as a baseline. Results: The average flexural strength ranged from 116.6 to 142.3 MPa in the following order with significant differences between each value: FS &gt; TE &gt; OM. The average E ranged from 6.8 to 13.2 GPa in the following order with significant differences between each value: FS &gt; TE &gt; OM. The average R ranged from 0.77 to 1.01 MJ/mm3 in the following order: OM &gt; FS &gt; TE. The Sa values of the OM groups polished with CMP and SSD were found to be significantly lower than those of the other resin composites, regardless of the finishing method. The GU values appeared to be dependent on the material and the finishing method used. The OM specimens polished with SSD showed significantly higher GU values than those polished with CMP. Most of the resin composites polished with SSD demonstrated significantly higher γS values compared to the other groups. Extremely strong negative correlations between Sa and GU in the combined data from the three resin composites and each resin composite and between Sa and γS in the OM specimens were observed; GU showed a strong positive correlation with γS in the same material. Conclusion: These findings indicate that both flexural and surface properties are material dependent. Furthermore, the different finishing and polishing methods used in this study were observed to affect the Sa, GU, and SFE of the resin composites.

The Leaf

2018 ◽  
Author(s):  
David R. Dalton
Keyword(s):  
Fatty Acids ◽  
Hydroxyl Group ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Electromagnetic Spectrum ◽  
Hydroxystearic Acid ◽  
Reflection And Transmission ◽  
Visible Part ◽  
Leaf P ◽  
Long Chain

Grape leaves are thin and flat. As is common among leaves in general, they are composed of different sets of specialized cells. Today, on average, sunlight reaching their surface is about 4% ultraviolet (UV) (<400 nm), 52% infrared (IR) (>750 nm) and 44% visible (VIS) radiation. Little of the UV and IR are used by plants. As with other leaves that are green, only the red and blue ends of the visible part of the electromagnetic spectrum are absorbed, thus leaving green available by reflection and transmission. On the surface of the leaf (Figure 8.1), the cells of the outermost layer (the epidermis) are designed to protect the inner cells where the workings needed for gathering the sunlight used for photosynthesis and other chemistry necessary to the life of the plant are found. That is, the more delicate cells, beneath the epidermis, are involved in production of carbohydrates as well as the movement of nutrients in and products out of the leaf. The epidermis, exposed to the atmosphere, has cells that are usually thicker and are covered by a waxy layer made up of long- chain carboxylic acids that have hydroxyl groups (–OH) at or near their termini. These so-called omega hydroxy acids can then form esters using the hydroxyl group of one and the carboxylic acid of the next. This yields long-chain polyester polymers called “cutin.” As indicated in the earlier discussion of cells and, in particular, regarding the fatty acids of cell walls, the fatty acids found in the epidermis generally consist of an even number of carbon atoms, and for cutin, the sixteen carbon (palmitic acid) family (Figure 8.2) and the eighteen carbon family (oleic acid bearing a double bond or the saturated analogue stearic acid) are common. While one terminal hydroxyl group is usual (e.g., 16-hydroxypalmitic acid, 18-hydroxyoleic acid, or its saturated analogue 18-hydroxystearic acid) more than one (allowing for cross-linking) is not uncommon (e.g., 10,16-dihydroxypalmitic and 9,10,18-trihydroxystearic acid).

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