Proportion Of Trans Research Articles

Polymeric microstructures and dielectric properties of polynorbornenes with 3,5-bis(trifluoromethyl)biphenyl side groups by ring-opening metathesis polymerization

exo-Polynorbornenes containing bis(trifluoromethyl)biphenyl side groups were synthesized by ring-opening metathesis polymerization using different Grubbs' catalysts, the microstructures of the polymer chains were established using NMR and IR spectroscopy. The influence of monomer and catalyst structures on chain microstructure was revealed and the correlation of properties with microstructure was investigated in detail. The exo-poly(N-3,5-bis(trifluoromethyl)biphenyl-norbornene-pyrrolidine) (exo-PTNP) and exo-poly(N-3,5-bis(trifluoromethyl)biphenyl-norbornene-dicarboximide) (exo-PTNDI) formed using Ru-I show a trans double bond bias of 67% and 83%, respectively, whereas the corresponding polymers formed using Ru-III have lower contents of trans double bond, 30% and 50%, respectively. Compared to the highly trans endo-PTNP formed using Ru-I, which is isotactic and has a dielectric constant of about 20, the endo-PTNP formed using Ru-III, the exo-PTNDIs and the exo-PTNPs formed using Ru-I and Ru-III all have different proportions of trans and cis double bonds, they are atactic and display relatively low dielectric constants, in the range 6 to 9. DSC measurements indicate some dependence of Tg, varying 161 to 221 °C, on tacticity and cis/trans ratios with higher trans contents tending towards higher Tg. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4786–4798

Effect of supplementation of fish and canola oil in the diet on milk Fatty Acid composition in early lactating holstein cows.

This study examined the effects of supplementation of fish oil and canola oil in the diet on milk yield, milk components and fatty acid composition of Holstein dairy cows in early lactation. Eight multiparous early lactation Holstein cows (42±12 DIM, 40±6 kg daily milk yield) were fed a total mixed ration supplemented with either 0% oil (Control), 2% fish oil (FO), 1% canola oil +1% fish oil (FOCO), or 2% canola oil (CO) according to a double 4×4 Latin square design. Each period lasted 3 wk; experimental analyses were restricted to the last week of each period. Supplemental oils were added to a basal diet which was formulated according to NRC (2001) and consisted of 20% alfalfa, 20% corn silage and 60% concentrate. Milk yield was similar between diets (p>0.05), but dry matter intake (DMI) was lower (p<0.05) in cows fed FO diet compared to other diets. Milk fat percentage and daily yield decreased (p<0.01) with the supplementation of fish and canola oil. The daily yield and percentage of milk protein, lactose and solids-not-fat (SNF) were not affected by diets (p>0.05). The proportion (g/100 g fatty acids) of short chain fatty acids (SCFA) decreased and polyunsaturated fatty acids (PUFA) increased (p<0.05) in milk of all cows fed diets supplemented with oil. The proportions of 6:0, 8:0, 10:0 12:0 and 14:0 fatty acids in milk fat decreased (p<0.01) for all diets supplemented with oil, but the proportions of 14:1, 16:0 and 16:1 fatty acids were not affected by diets (p>0.05). The proportion of trans(t)-18:1 increased (p<0.01) in milk fat of cows fed FO and FOCO diets, but CO diet had the highest proportion of cis(c)-11 18:1 (p<0.01). The concentration of t-10, c-12 18:2, c-9 t-11 18:2, 18:3, eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6) increased (p<0.05) in FO and FOCO diets in comparison with the other two diets. These data indicate that including fish oil in combination with canola oil significantly modifies the fatty acid composition of milk.

Analysis of management of pituitary adenoma in old age

Objective To study the pattern of illness and principle of management of pituitary adenoma in elder people. Method Clinical findings from 108 cases with pituitary adenoma in elder patients (over 60 years)were studied retrospectively, and were compared with 970 cases of different age who were hospitalized at the same period. The results were processed statistically and the incidence rate, clinical manifestations,pathological type and choices of surgical approach were figured out. Results Elder patients accounted for about 10% of all cases with pituitary adenoma. The specificities in size of the tumor, clinical manifestations, pre- operative complications, choices of operative procedure, recovery rate and postoperative complications were found statistically significant. Conclusions The onset of pituitary adenoma is insidious in elder people. Most cases show off bigger size and invasive growth pattern. Clinical features include prominent visual deterioration and patients are usually associated with pathological change of other systems and even functional failure of other organs. They require strict pre - operative preparation since the risk of operation is high and the patients are vulnerable to various types of post - operative complications. The proportion of trans - cranial approach had been increased in adopted surgical procedures. Pituitary adenoma in elder people should be paid special attention and managed comprehensively. Key words: Pituitary neoplasms; Aged; Diagnosis; Treatment

Cadmium-induced changes in the membrane lipid composition of maize plants

The effect of 10, 25 and 50 μM Cd(NO 3 ) 2 on the fatty acid composition was investigated in young maize seedlings ( Zea mays L., hybrid Norma). After 7 days’ exposure to cadmium slight changes were observed in the fatty acid composition, which were more pronounced in the roots than in the leaves. In the leaves cadmium did not affect the lipid composition of the monogalactosyldiacylglycerol (MGDG) or digalactosyldiacylglycerol (DGDG) fractions, while in the phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) fractions there was a decrease in the proportion of hexadecanoic acid (16:0) and an increase in the level of linoleic acid (18:2) and linolenic acid (18:3). The proportion of trans -Δ3-hexadecanoic acid in leaf PG also decreased. In the roots significant changes were observed in all the fractions examined after Cd stress. In the MGDG the level of stearic acid (18:0) and oleic acid (18:1) decreased, but that of 18:2 and 18:3 increased. In the case of PE the amount of 16:0 decreased, while that ...

Perfil de ácidos graxos e conteúdo de ácido linoléico conjugado no leite de vacas alimentadas com a combinação de óleo de soja e fontes de carboidratos na dieta

A gordura do leite de 12 vacas lactantes 7/8 Holandês-Gir foi utilizada para avaliar o efeito de diferentes dietas sobre o perfil dos ácidos graxos (AG) e o conteúdo de ácido linoléico conjugado (CLA) no leite. Os tratamentos consistiram de concentrados formulados com milho (MI) ou sua total substituição por farelo de trigo (FT) ou por polpa cítrica (PC), associados ou não a óleo de soja (0 e 2,25%). A análise cromatográfica indicou que mais de 95% dos ácidos graxos (AG) foram recuperados. Não foi verificada interação significativa da presença de óleo e fonte de carboidratos em qualquer variável avaliada, à exceção das concentrações de trans-10 C18:1 e da proporção de trans-10 C18:1 e trans-11 C18:1 nos totais trans- C18:1 do leite. A fonte de carboidrato utilizada não influenciou o perfil de ácidos graxos do leite ou o teor de CLA. A inclusão de óleo de soja aumentou em 35% os AG insaturados do leite e reduziu em 14% os AG saturados, principalmente os de cadeia curta (9,66 vs 7,59 g/100 g) e os de cadeia média (51,80 vs 40,86 g/100 g). As dietas com óleo promoveram aumento dos AG de cadeia longa (32,17 vs 46,47 g/100 g), principalmente C18:0 (9,44 vs 13,63 g/100 g), C18:1 (20,28 vs 29,74 g/100 g) e C18:2 (2,16 vs 2,92 g/100 g). A concentração de CLA cis-9 trans-11 C18:2 foi aumentada em 230% (0,46 vs 1,06 g/100 g) na presença de óleo. A concentração dos AG cis e trans-C18:1 também foi aumentada; trans-11 C18:1 foi o principal isômero trans, embora a concentração de trans-10 C18:1 tenha se elevado de 0,28 para 1,11 g/100 g na presença de óleo, sendo influenciada pela fonte de carboidrato. Os tratamentos MI, FT e PC resultaram em conteúdos deste isômero semelhantes na gordura do leite, mas, na presença de óleo, as fontes MI e FT proporcionaram valores muito superiores aos obtidos com PC, indicando diferentes rotas de biohidrogenação.

CONTENT OF TRANS C18:1 AND TRANS C18:2 ISOMERS AND CIS9TRANS11 C18:2 (CLA) IN FAT BLENDS

ABSTRACT The content ofTrans C18:1,Trans C18:2 and cis9trans11 C18:2 (CLA) in the marketed fat blends was evaluated by capillary gas chromatography and silver thin‐layer chromatography. For comparison, the level of these acids was also determined in commercial butter, purchased at the same time. The content ofTrans C18:1 in fat blends showed that half of the examined products containedTrans C18:1 at 1.9–4.4%, while the other half contained 8.2–24.2%Trans fatty acids. The fat blends with a high total content ofTrans C18:1 were characterized by a high proportion ofTrans 6–8 andTrans 9 isomers. TheTrans 9 C18:1 in these products constituted 15.0–22.5% of the totalTrans C18:1. The level ofTrans C18:2 in fat blends examined ranged from 0.3 to 1.1%. Seven of the 18 tested fat blends contained, apart from cis‐trans andTrans‐cis C18:2, alsoTrans‐trans C18:2 in the 0.03–0.4% range. In all fat blends examined, CLA was present. The products with a low level ofTrans C18:1 contained CLA at 0.3–1.0%. The content of CLA in the fat blends with high level ofTrans C18:1 did not exceed 0.3%.

Real-time FTIR and WAXS studies of drawing behavior of poly(ethylene terephthalate) films

The development of molecular orientation and crystallization was studied during uniaxial drawing of poly(ethylene terephthalate) (PET) films, which was immediately followed by subsequent taut annealing at the drawing temperature. The behavior was monitored in real time throughout the drawing and annealing using dynamic FTIR spectroscopy and in situ WAXS measurements using the Daresbury Synchrotron Radiation Source. Films were drawn at 80 and 85°C at varying strain rates (0.001–0.7 s−1). The true stress–strain behavior was determined at each of the drawing conditions and the density and optical anisotropy of unloaded samples was measured. The IR spectra were analyzed using curve reconstruction procedures developed previously, and they showed that orientation of the phenylene groups and the trans glycol conformers occurred before significant gauche–trans conformational changes could be seen. The onset of crystallization, defined as the point that the crystalline 105 reflection could be first observed using WAXS, was not found to correlate with any specific change in the proportions of trans and gauche isomers nor with any feature on the stress–strain curve. However, it was clear that, for these comparatively low strain rates, crystallization occurred during the drawing process while the crosshead was moving and the draw ratio was increasing. The orientation of the crystallites was calculated from the 105 reflection observed in a tilted film, transmission geometry. The crystallites were found to form at a draw ratio of about 2.5 with high orientation values (P2> 0.8) that increased during drawing and annealing to P2 values of 0.95, irrespective of the drawing conditions. Semiquantitative measurements of crystallinity showed that the fraction of crystalline material that developed during drawing decreased with increasing strain rate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1825–1837, 2001

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion

The proportion of geometrical hydroperoxide isomers generated by aerobic oxidation of methyl linoleate (18:2 Me) in either aqueous emulsion consisting of Tris-HCl buffer (pH 7.4) or in a homogeneous dichloromethane solution was determined to understand the mechanism of lipid oxidation in different reaction systems. Four geometrical isomers were generated after oxidation of 18:2 Me in dichloromethane: methyl 13-hydroperoxy-cis-9, trans-11-octadecadienoate, methyl 13-hydroperoxy-trans-9,trans-11-octadecadienoate, methyl 9-hydroperoxy-trans-10,cis-12-octadecadienoate, and methyl 9-hydroperoxy-trans-10, trans-12-octadecadienoate in the ratios of 1:4:1:4, respectively. The ratios between each isomer did not change until the peroxide value (PV) increased to 58 meq/kg. Oxidation of 18:2 Me in aqueous emulsion yielded the same geometrical isomers of hydroperoxide. However, the ratios were different: 3:2:3:2 until the PV increased to 110 meq/kg. Predominant (60%) formation of trans,trans hydroperoxide isomers was obtained in the oxidation of a mixture of 18:2 Me and methyl laurate (12:0 Me). These results are interpreted to reflect the importance of the concentration of hydrogen atom-donating equivalents to the kinetic preference for different products. The high effective concentration of hydrogen donors in the oxidation of 18:2 Me in emulsions favored the formation of the less stable cis,trans isomers. The lower concentration of hydrogen donor in the dichloromethane solution effectively slowed hydrogen donation and led to the strong preference for the more stable trans,trans isomers. This interpretation was further tested by preparing emulsions of 18:2 Me and 12:0 Me to dilute concentration of hydrogen-donating species using the nonhydrogen-donating 12:0 Me. Consistent with the proposed hypothesis, the proportion of trans,trans isomers increased as a result of 12:0 Me addition.

Characterization of monomers produced from thermal high‐pressure conversion of meadowfoam and oleic acids into estolides

The monomers produced from thermal high‐pressure conversion of meadowfoam or oleic acids into estolides were characterized as a complex mixture of fatty acids. Mild reaction conditions produced little change in the starting acids. However, vigorous reaction conditions,e.g. ≥3 h at 250°C with stirring, significantly altered the starting fatty acids.Cis/trans isomerization occurred readily, with the proportion oftrans isomers reaching 57%. In addition, the double bonds migrated throughout all positions of the hydrocarbon chain with concentrations diminishing outward from the starting double bond position. Branching was also observed to a small extent under these conditions and was even more pronounced in the absence of water. Lactones were also identified in the reaction mixture, with contents near 16% in the meadowfoam series. All products can be explainedvia carbocation rearrangement mechanisms that result from protonation of the starting olefins.

Continuous slurry hydrogenation of soybean oil with nickel catalysts

AbstractSoybean oil was hydrogenated continuously in the presence of nickel catalysts. The iodine value of the products was varied by changing the oil flow rate and temperature of the reaction. Sulfur‐promoted nickel catalyst increased the selectivity for linolenate hydrogenation, but formed much higher proportions oftrans isomers. Linoleate selectivity improved with temperature with both nickel and sulfur‐promoted nickel catalysts, buttrans isomerization also increased. The feasibility of this continuous reactor system was demonstrated as a practical means to prepare hydrogenated stocks of desired composition and physical characteristics at high throughput.

The interaction of vinyl acetate and allyl acetate with chloro-bridged platinum(II) complexes [Pt 2Cl 4(PR 3) 2]: Crystal structure of cis-[PtCl 2(PMe 2Ph2)(CH 2=CHOCOCH 3)

Five complexes of type cis-[PtCl 2(PR 3)Q] (PR 3 =PMe 3, PMe 2Ph, PEt 3; Q = CH 2 CHOCOCH 3 or CH 2=CHCH 2OCOCH 3) have been prepared. The crystal structure of cis-[PtCl 2[PME 2Ph)(CH 2=CHOCOCH 3)] is described. Crystals of cis-[PtCl 2(PME 2Ph)(CH 2-CHOCOCH 3)] are triclinic, with a 8.441(4), b 13.660(5), c 7.697(3) Å, a 101.61(3)°, β 111.85(3)° γ 95.22(3)°, p P1, Z = 2. The structure was determined from 2011 reflections I σ 3σ ( I) and refined to R = 0.037. The CH 3COO grouping is syn to the cis-PMe 2Ph ligand, with bond lengths of PtCl (trans to P) 2.367(3), PtCl ( trans to olefin) 2.314(3), PtP 2.264(2), and PtC of 2.147(12) and 2.168(11) Å. The complexes cis-[PtCl 2- (PR 3)Q] were studied by variable temperature 1H and 31P NMR spectroscopy. Spectra of the vinyl acetate complexes were temperature dependent as a result of rotation about the platinum—olefin bond. The rotation was “frozen out” at ca. 240 K; for cis-[PtCl 2(PME 2Ph)(CH 2=CHOCOCH 3] Δ G≠ (rotation) 15.0 ± 0.2 kcal mol -1. NMR parameters for the rotamers are reported. NMR studies of the interaction between chloro-bridged complexes of type [Pt 2Cl 2(PR 3) 2] (PR 3 = P-N-Pr 3 or PMe 2Ph) and vinyl acetate shows that even at low temperatures (213 K) equilibrium favours the bridged complex and the proportion of trans-[PtCl 2(PR 3)CH 2=CHOCOCH 3)] is very small e.g. 2%. The allyl acetate complexes cis-[PtCl 2(PR 3)(CH 2=CHCH 2OCOCH 3)] showed only one rotamer over the range 333–213 K. Reversible dissociation of cis-[PtCl 2(PMe 2Ph)- (CH 2=CHCH 2OCOCH 3)] to [Pt 2Cl 4(PMe 2Ph) 2] + allyl acetate was studied at ambient temperature. At low temperatures e.g. 213–190 K addition of allyl acetate to a CDCl 3 solution of [Pt 2Cl 2(P-n-Pr 3) 2] reversibly gave some olefin complex trans-[PtCl 2(P-n-Pr 3)(CH 2=CHCH 2OCOCH 3)] and some O-bonded complex trans-[PtCl 2(P-n-Pr 3)(CH 2=CHCH 2OCOCH 3)].