Group CH Research Articles

Effects of Cannabis sativa extract on growth performance, meat physicochemical properties, and oxidative status in chickens challenged with Clostridium perfringens and lipopolysaccharide

Abstract The present study aimed to evaluate the effect of a Cannabis sativa extract rich in cannabidiol in the diet of chickens under induced stress conditions. This was achieved through the administration of subclinical doses of inflammation-inducing Clostridium perfringens bacteria and lipopolysaccharide, which are commonly found in poultry production. A total of 204 male Ross (line 308) chicks were divided into 6 groups, with variations in Cannabis sativa extract addition (30 g/1000 g of feed on top) and stress induction methods. At 21 and 22 days of age the birds from the CH1 group were infected (per os) with 1 mL of inoculum (brain-heart infusion medium) containing approximately 108 CFU/mL of C. perfringens. At the same times birds of group CH2 were per os administered lipopolysaccharide in a dose of 1 mL containing 250 μg/kg body weight of. The results indicate that incorporating a 30 g/1000 g Cannabis sativa extract (CBD) additive in chicken diets leads to an increase in ultimate body weight and maintains weight under stressed conditions (P<0.05), without adverse effects on slaughter analysis. Moreover, CBD supplementation does not significantly affect (P>0.05) the physical and chemical parameters or primary composition of breast muscle and liver. However, it may alter the n-6/n-3 acid ratio. Additionally, CBD supplementation helps maintain blood biochemical and antioxidant parameters, supporting overall chicken body homeostasis stressed. Incorporating Cannabis sativa extracts at 30 g/1000 g of feed presents a potential protective measure to enhance poultry farming in challenging intensive production conditions.

Sustainable production of glutamic acid by Enterobacter sp. strain isolated from cheese for potential protein biosynthesis: Optimization by Response Surface Methodology

Glutamic acid (GA), is a very important biomolecule that is widely utilized in food, pharmaceutical, agricultural, medical, and chemical-based industries. The present study utilized acid-treated wheat bran as a carbon source to produce GA. The identified Enterobacter sp. strain BUK_BTE17 MW597320 after screening yield 0.989 g/L GA. The GA production was optimized by CCD of RSM. The effects of independent factors on GA production by Enterobacter sp. were studied. The result obtained indicated a maximum experimental production of 8.451 g/L at the optimized conditions of pH (6), Tempt, (30 °C), substrate conc (6 g/L), and incubation (48 h) was not statistically different from the predicted value of 8.565 g/L at p < 0.05. The G A crystals were examined by TLC, and FTIR which showed the wave numbers of 3268 cm−1, 1640 cm−1, and 2125 cm−1 corresponding to the functional groups CO, NH2, and CH2 for glutamic acid, respectively.

Electrical and optical properties of polyamide 6 nanocomposites with multi-walled carbon nanotubes

In this work, quantum chemical modeling, electrical conductivity, Raman scattering, and photoluminescence of polyamide 6 nanocomposites with multi-walled carbon nanotubes (0–2.5 vol%) were investigated. It was shown that the concentration dependence of the electrical conductivity obeys the percolation theory and has the value of percolation threshold 1.41 vol%. The conductivity value of the composite at 2.5 vol% nanotubes is 1.1*10-3 S/cm. It was found that in PA6 nanocomposites filled with MWCNT an increase in the concentration of nanotubes from 0.001 to 0.015 vol%, namely in the pre-percolation region of electrical conductivity, due to a significant restructuring of the Raman spectra, which consists in a shift of the vibrational modes of the methylene groups CH2 and amide I, as well as in a change of their relative intensities. From the photoluminescence spectra of PA6-MWCNT, it can be seen, that the carbon nanotubes largely determine the conformational changes in the polymer matrix and have little effect on the defective structure of the polymer itself.The goal: to establish the mechanisms of electrical conductivity and the interaction of nanotubes with polyamide macromolecules and its influence on the electronic and optical properties of nanocomposites of polyamide multi-walled carbon nanotubes.

Production of liquid hydrocarbons by thermo-acidic method from waste high-density polyethylene.

The study explains the production of useful liquid hydrocarbons by thermo-acidic catalytic thermal degradation of waste high-density polyethylene. A comparative study of the liquid samples with or without catalysts. Energy demand is high in the world. Waste plastic conversion is nowadays a concern of interest research for scientists. HDPE (High-density polyethylene) is the most common plastic used in households. Different types of catalysts and techniques have been used in the alteration process of waste HDPE. This paper deals with the kandite group of catalyst kaolin and the montmorillonite group of catalyst sodium bentonite in acid-activated mutated form. This paper aims to explore the prominent utilization of kaolin clay and sodium bentonite clay minerals as a catalyst for the alteration of waste HDPE into fuel resources and to develop a cost-effective recycling experimental set-up for plastic waste conversion. Thermo-catalytic acid activation has been done for clay mutation. Hydrochloric acid-activated catalysts have been used in this study. FT-IR (Fourier Transform Infrared Spectroscopy) and GC-MS (Gas Chromatography and Mass Spectrometer) techniques have been used to explore the prominent compounds in the product samples. Maximum energy per photon for RO (Parent Oil/Raw Oil) and AO(Acid treated thermo-catalytic oil) samples are respectively 58034.01×1024 Joules and 59271.40×1024 Joules concerning wave numbers 2921.42 and 2983.71 cm-1. Compounds of functional groups C-CH3, CH2, alkenes, and CH3 have been identified for RO and AO samples. Less gaseous hydrocarbons 31.79% (outcomes) or 29.66 % (production yield) and 150.06 % of increment in wax have been calculated after using acid-treated catalysts. Aliphatic compounds like alkanes and alkenes are present in the samples. A mixture of acid-treated kaolin and acid-treated sodium bentonite as the catalysts for degrading waste HDPE into liquid oil greatly reduces wax formation. Average outcomes and production of liquid hydrocarbons are good results with the acid-treated catalytic degradation of HDPE waste. One remarkable fact is that the yield percentage of liquid products is higher in acid-activated catalytic thermal degradation.

Effect of active composite ionic liquids treatment on chemical structure and wettability of coal

To investigate the effect of different ionic liquid composite solutions on the wettability and chemical structure of coal dust, 14 ionic liquid compound solutions with various composite ratios were selected to act on long flame coal. Through the contact angle measuring instrument, 14 ionic liquid compound solutions were optimized, and 4 ionic liquid compound solutions with the same anion/cation were selected. The wetting agent with good water retention performance in the 4 kinds of composite solutions was selected by the water retention experiment. FTIR was used to research the change of functional group content in the coal treated by the 4 kinds of composite solutions. The results displayed that the contact angle of [Bmim][BF4]/[Emim][BF4] solution with the mixture ratio of 1:5 on the coal surface reached the min value of 34.483°. The [Bmim][BF4]/[Bmim][Cl] solution with a compounding proportion of 1:5 had the best water retention performance. The hydrophilic and hydrophobic functional groups of long flame coal treated by ionic liquid composite solutions had changed significantly. The [Bmim][BF4]/[Emim][BF4] composite solutions with the compounding proportion of 2:4 and 1:5 and the [Bmim][BF4]/[Bmim][Cl] composite solutions with the compounding proportion of 2:4 and 1:5 can not only increase the content of hydrophilic functional groups OH⋯O, Si–O–Si, COC, CO, and CO, but also decrease the content of hydrophobic functional groups CH2 and 2H. By analyzing the relationship between coal wettability and functional groups, it was discovered that the hydrophilic functional group CO was the primary functional group affecting the contact angle, and –OH and COC were the primary functional groups affecting the moisture content of coal samples. In this essay, the novel composite wetting agent type was prepared by compounding ionic liquid solutions with the same anion/cation in pairs, which has certain guiding significance for further using the novel composite moistening agent to improve the wettability of coal and preventing and control mine dust.

Characteristics of Paraffin Shielding of Kartini Reactor, Yogyakarta

The National Nuclear Energy Agency (BATAN) Yogyakarta uses two kinds of paraffin for shielding radiation of Kartini reactor. For developing BNCT research, the radiation attenuation capability of paraffin has been analyzed to find out the coefficient attenuation, density, and composition of both kinds of paraffin. The components of the paraffin were analyzed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy characterization. Paraffin P1 has a density of 0.689 gr/mL and paraffin P2 is 0.578 gr/mL. Paraffin samples P1 and P2 were the sample content of functional group CH, CH2, and OH when analyzed by FTIR. Paraffin P2 had an additional content namely CO. The concentration of carbon (C) and oxide (O) of paraffin P2 was much greater than that of paraffin P1. Hydrogen (H) in the paraffin has the function of moderating neutrons, but hydrogen content in both kinds of paraffin could not be detected by EDX. The acquired neutron coefficient attenuation of paraffin P2 was 0.0382 cm-1 and the gamma coefficient attenuation was 0.0535 cm-1.

Correlation and prediction of thermodynamic properties of dilute solutes in water up to high T and P. II. Normal fluids CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10, functional groups CH3 and CH2

Fugacity coefficients of dilute aqueous solutions of six species belonging to normal fluids (CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10) as well as functional groups CH3 and CH2 have been evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m−3). The basis of the approach is a correlation developed for the function, A12∞=V2∞/κTRT, that includes known constraints: second virial coefficients at low water densities, hard sphere behavior at high water densities, near-critical principles, and corresponding-states relations. A comparison with literature data at subcritical (Henry's and vapor-liquid distribution constants) and supercritical temperatures (fugacity coefficients) is made. For aqueous CO2, the agreement with literature data is generally satisfactory. It is shown that for other solutes existing disagreements can be traced mostly to the values of the second cross virial coefficients employed in the literature models, suggesting the room for improvement of existing recommendations.

A Novel Group-based Correlation for the Ignition Delay Time of Paraffinic-type Fuels

ABSTRACT A group contribution equation is proposed for the prediction of the cool flame and main auto-ignition delay time for linear and slightly branched paraffinic fuels. The experiments were carried out in a constant volume combustion bomb where pressure and temperature were modified for five linear paraffinic hydrocarbons (n-C10, n-C12, n-C14, n-C16 and n-C18) and three C16 isomers with different degree of branching (2-methylpentadecane; 2,6,10-trimethyltridecane and 2,2,4,4,6,8,8-heptamethylnonane). An Arrhenius-type correlation is proposed, with extended parameters to the number of groups CH3, CH2 and CH and the equivalence ratio. The proposed equation has enough accuracy to estimate the autoignition delay times of paraffinic fuels (from n-dodecane to n-octadecane) for temperature ranging from 535 to 650ºC and pressure from 11 to 21 bar.

Raman and FT-IR investigation of neutron and fission-fragment irradiated DAP polymer

The polymer Diallyl Phthalate (DAP), commonly used as solid-state nuclear track detector (SSNTD), has been characterized via optical microscopy and Raman and FT-IR spectroscopies in three distinct processes: i) without irradiation; ii) irradiated by neutrons and induced fission fragments and iii) as a function of the chemical etching time. The detectors were exposed to fission fragments from the induced fission of 235U and to the neutrons themselves. The optical microscopy provides information about the morphological changes, while the spectroscopic techniques provide physical and chemical information over the detector molecular structure. The irradiation and chemical etching induces molecular degradation and cross-linking of the detector chemical structure as observed in the Raman and FT-IR analyses. According to the spectral profile analyses, the strength of the functional groups OCOO, CH, CHCH, CCH, COC, CCH3, C(CH3)2, CCH3, CO, CH2 decrease and additional CO2 gases and OH groups are produced. Therefore, the characterization process performed in this work is essential to better comprehend the behavior of the DAP molecular structure under irradiation and chemical etching and also to better understand the track formation process which is related to the etching kinetics.

Prediction of the total acid number (TAN) of colombian crude oils via ATR–FTIR spectroscopy and chemometric methods

Reactions as the attack by naphthenic and hydrogen sulfide have caused corrosion problems in the petroleum industry due to they affect the crude oil heating furnaces and distillation towers at temperatures between 220 and 400 °C. The total acid number (TAN) measurement has been used as a test to quantify the acid compounds in crude oils and has shown to be a reliable indicator of their corrosion degree. However, the standard method for the TAN measurement, ASTM D-644, involves long times, environment unfriendly wastes and high costs for each analysis. A more appropriate method for the TAN determination is implemented in this paper, by correlating Fourier transform infrared spectroscopy (FTIR) spectral data of the samples with the standard method measurements using multivariate regression models. In particular, the intensities and frequencies of their mid-infrared attenuated total reflectance (MIR-ATR) spectra (4000 - 400 cm−1) are used as independent variables of several principal component regression (PCR) and partial least squares regression (PLSR) models. The latter are employed to correlate the spectra with their respective TAN values so as to obtain a suitable prediction model. Twenty-six (26) samples of Colombian crude oils are used for the study with a TAN ranging from 0.1 to 6.8 mg KOH/g crude oil (ASTM D-664). The models are evaluated according to the coefficient of determination (R2), the root mean square error of calibration (RMSEC) and of prediction (RMSEP). The best model is obtained via PLSR using as few as four components (i.e. factors), which attains a calibration R2 of 0.981 and an RMSEC of 0.317 mg KOH/g crude oil, while for prediction it attains an R2 of 0.996 and an RMSEP of 0.160 mg KOH/g crude oil. It is observed that the functional groups COOH, CH3 and CH2 contribute the most to the prediction models. The designed methodology is faster and environmentally friendly since it does not require sample pretreatment and the use of toxic reagents, and of low-cost compared with the standard procedure since FTIR measurements can be easily taken anywhere using a hand-held or portable spectrometer and a laptop.

Synthesis, physicochemical and biological evaluation of tacrine derivative labeled with technetium-99m and gallium-68 as a prospective diagnostic tool for early diagnosis of Alzheimer’s disease

Design, physicochemical and biological studies of novel radioconjugates for the early diagnosis of Alzheimer's disease, based on the newly synthesized tacrine derivatives were performed. Novel tacrine analogues were labeled with technetium-99m and gallium-68. For all obtained radioconjugates ([99mTc]Tc-Hynic-(tricine)2NH(CH2)ntacrine and [68Ga]Ga-DOTA-NH(CH2)9tacrine, where n = 2–9 denotes the number of methylene groups CH2) the studies of physicochemical properties (lipophilicity, stability in the presence of an excess of standard amino acids cysteine or histidine, human serum and in cerebrospinal fluid) were performed. For two selected radioconjugates [99mTc]Tc-Hynic-(tricine)2NH(CH2)9Tac and [68Ga]Ga-DOTA-NH(CH2)9tacrine (characterized with the highest lipophilicity values) the biological tests (inhibition of cholinesterases action, molecular docking and biodistribution studies) have been performed. All novel radioconjugates showed high stability in biological solutions used. Both selected radioconjugates proved to be good inhibitors of cholinesterases and be able to cross the blood-brain barrier. Radioconjugates [99mTc]Tc-Hynic-(tricine)2NH(CH2)9tacrine and [68Ga]Ga-DOTA-NH(CH2)9tacrine fulfil the conditions for application in nuclear medicine. Radiopharmaceutical [68Ga]Ga-DOTA-NH(CH2)9tacrine, due to increased accuracy and improved sensitivity in PET imaging, may be better potential diagnostic tool for early diagnosis of Alzheimer’s disease.

Geochemistry of trace elements and their relations with organic matter in Kuh-e-Sefid phosphorite mineralization, Zagros Mountain, Iran

The Kuh-e-sefid phosphorite is located in Zagros fold-thrust belt, in the Ramhormoz area, northeast of Khuzestan province. Phosphorite mineralization occurred as phosphorite lenses of Eocene age hosted by the Pabdeh Formation. The aim of this study is to investigate the role of organic matter in trace metal portioning during phosphorite mineralization in the Kuh-e-Sefid deposit. Field observations and petrographic studies indicate that the host-rock of mineralization is mainly consists of shale, marl, and limestone with textures varying from wackestone to packestone. Phosphoritic components, such as authigenic apatite, pellets, intraclasts, fish skeletal fragments, and micro-fossils are present. Moreover, non-phosphorite minerals including calcite, glauconite, pyrite, iron-oxide and to a lesser extend montmorillonite with microcrystalline quartz occurred in phosphorite lenses. NASC-normalized patterns of REEs showed the enrichment of Heavy Rare Earth elements (HREE) and negative Ce anomaly with co-existence of slightly negative and positive Eu anomalies represent a transitional change from oxic to anoxic sedimentation conditions during mineralization. Importantly, Ni/Co versus V/Cr ratios and V/(V + Ni) diagrams confirmed dysoxic to anoxic conditions for the hydrocarbon-bearing phosphorite and hosted shales, while non-hydrocarbon-bearing phosphorites exhibit oxic conditions. The FTIR studies revealed qualitative information about the component bonds and nature of the organic matter and mineral-organic bonds like OH, carboxylic OH, carboxylic acid CO, CC alkaline, group CH2, CC aromatic, CH aliphatic, and aromatic stretching associated with phosphate mineralization. It seems that there is a link between a relatively high concentration of trace metals (i.e., REEs, U, Co, Zn, Ni, V, Sr and Mo) and phosphorites enriched in organic matter especially those of aromatic hydrocarbon groups.

Interaction between low molecular weight carboxylic acids and muscovite: Molecular dynamic simulation and experiment study

Interface phenomena between low molecular weight (LMW) carboxylic acids and muscovite was investigated through molecular dynamic simulation and experiment, where the typical monocarboxylic acids including formic acid (C1), acetic acid (C2), propionic acid (C3) and butyric acid (C4) were used as models. Density distribution, adsorption energy, root mean square dynamic (RMSD) of carboxylic acids on water-muscovite interface were calculated through molecular dynamic simulation, and the advanced characterization methods, such as ATR-FTIR spectra, AFM images and contact angle were performed to test and verify the relative simulation findings. The molecular simulation showed that carboxylic acids adsorbed on surface of muscovite through hydrogen bond between H atom of COOH functional group of carboxylic acid and O atom of muscovite, belong to outer sphere adsorption, and ATR-FTIR spectra and AFM images confirmed this finding. Adsorption energy for long carbon chain carboxylic acid (C4) was higher than that for short carbon chain carboxylic acid (C1, C2 and C3) due to the effect of carboxylic acid diffusion on water-muscovite interface. The hydrophilic functional group COOH of carboxylic acids preferably adsorbed on muscovite surface, while the hydrophobic functional groups CH3 and CH2 of carboxylic acids were far from the muscovite surface. So, the hydrophobicity on muscovite surface increased due to the adsorption of carboxylic acids, which resulted in the increase of contact angle of water on muscovite surface.

Interface of polyimide–silica grafted with different silane coupling agents: Molecular dynamic simulation

ABSTRACTIn this article, the effects of different silane coupling agents: 3‐glycidyloxypropyltrimethoxysilane (GOTMS), 3‐aminopropyltriethoxysilane (APTES), and 3‐methacryloxypropyltrimethoxysilane (MPTS), on the interface between polyimide (PI) and silica (SiO2), were investigated using molecular dynamic simulation. The results indicate that binding energy between PI molecules and SiO2 surface mainly comes from van der Waals interaction. Proper silane coupling agents generate a thin membrane on the surface of SiO2, which improves the thickness of the transition layer between PI molecules and SiO2 surface. And density of the transition layer was enhanced by APTES significantly. In addition, amino group (NH2) improves the electrostatic interaction between PI molecules and SiO2 surface rather than epoxy group (CHCH2O) and methacrylic oxide group (OCOC(CH3)CH2). As a result, APTES enhances the binding energy effectively. However, excessive silane coupling agent increases the distance between PI matrices and SiO2, which deteriorates performance of the interface. In addition, GOTMS and MPTS generate a thick and dense membrane on SiO2 surface, which induces the loose transition layer and poor binding energy. Overlap parameter between PI molecules and SiO2 surface grafted with silane coupling agent can be employed to evaluate the transition layer successfully. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45725.

Contaminations of inner surface of magnesium fluoride windows in the ‘Expose-R’ experiment on the International Space Station

AbstractA series of experiments was carried out previously on board of the International Space Station in ‘EXPOSE-R’, a multi-user expose facility, provided by European Space Agency attached to the external surface of the Russian Segment. In one experiment, spores of microorganisms and species of higher plant seeds, in heat-sealed polymer bags were irradiated by solar radiation passed through MgF2windows in a high space vacuum. After sample exposure, it was found that in many cases the inner surfaces of windows were contaminated. Analysis of the contamination revealed the presence of chemical groups CH2, CH3, NH, OH, C═O, Si–CH3(Demetset al.in 2015). Their presence in deposits was explained by photofixation of gaseous precursors – some of the vapours of glues and additives in polymeric materials in the core facility of ‘Expose-R’. Carbon-, oxygen- and silicon-containing groups may be deposited from outer intrinsic atmosphere. This atmosphere is connected with sample compartments and core facility. However, the presence of NH groups on inner surfaces of windows was not expected. This paper shows that the process responsible for carbon-, nitrogen- and oxygen-containing group formation can be a photopolymerization of caprolactam, which is released from the outer Nylon 6 layer of polymer bags under Solar vacuum ultraviolet radiation.

Dielectric and physico-chemical properties of epoxy-mica insulation during thermoelectric aging

Three stator bars were subjected to 1142 hours of thermoelectric aging. At intervals during this time, the aging of the insulation was investigated by capacitance (C) and dissipation factor (DF) measurements and by the physicochemical techniques of infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). Results indicated different degradation paths under discharge conditions, where the volume of voids within the insulation played a major role. Postcuring reactions were predominant during the first aging cycles. Such reactions were detected as reductions in capacitance and dissipation factor parameters, as a depletion of the chemical group epoxide at the absorption band 909 cm-1 as measured by FTIR, and as an increase of the glass transition temperature (Tg) of the epoxy resin. Since the postcuring reactions occur globally in the insulation, they were detected by both dielectric and physicochemical techniques. With the advance of the aging program the epoxy resin underwent structural changes, seen as modifications of functional groups CH2, CH3 and C=O. The air atmosphere where partial discharges occurred also promoted the formation of reactive species. When the air volume was high enough, the findings of FTIR measurements suggested a local degradation mechanism of mica involving cation exchange reactions between partial discharge byproducts and potassium layers in the mica.

New structural motif of hydrogensquarate anions in the presence of dl-Serinium cation. Spectral and structural elucidation

A new crystalline complex of dl-serine and squaric acid (H2Sq) in stoichiometric ratio 1:1 (dl-Ser·HSq) was synthesized, isolated and structurally characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n and its structure consists of a 3D supramolecular network of hydrogensquarate anions and serinium cations directed by intermolecular hydrogen bonding interactions. The 3D network is formed by hydrogen bonds with participation of CO–OH, hydrogensquarate ion and NH3+ group, (Sq) CO…OC (OH) (2.525 Å), –NH3+…OC (Sq) (2.915, 2.985 and 3.016 Å), hydroxyl group CH2–OH…OC (Sq) (2.739 Å), O…H–N+ (3.016 Å) and (C–OHA…OC (Sq) (3.242), respectively. The structural information shows a new structural motif, a non-classic α-chain of the hydrogensquarate anions with dihedral angle between neighbouring HSq− anions 43.66°. The Raman and infrared spectra of the new crystal were measured in the 4000–50 cm−1and 4000–400 cm−1 region frequency range respectively. The assignment of bands in infrared and Raman spectra of the crystal was performed on the basis of DFT (B3LYP) calculations, X-ray structural results and by the comparison with literature data.

Vapour liquid equilibria of monocaprylin plus palmitic acid or methyl stearate at P = (1.20 and 2.50) kPa by using DSC technique

The Differential Scanning Calorimetry (DSC) technique is used for measuring isobaric (vapour+liquid) equilibria for two binary mixtures: {monocaprylin+palmitic acid (system 1) or methyl stearate (system 2)} at two different pressures P=(1.20 and 2.50)kPa. The obtained PTx data are correlated by Wilson, NRTL and UNIQUAC models. The original UNIFAC group contribution method is also considered and new binary interaction parameters for the main groups CH2, CCOO, OH and COOH are regressed, to account for the non-idealities found in these lipid systems. Established thermodynamic consistency tests are applied and attest the quality of the measured data. In terms of relevance of the selected components, system 1 can be found in the purification and deodorization steps during the production of edible oils, while, system 2 can be found in the purification steps of biodiesel. It should be noted that no such data could be found in the open literature, not only for the specific components selected but also for the combination of the classes of components considered; that is, acylglycerol plus fatty acid or fatty ester.

Transmission of electronic substituent effects along polyenic chains: a quantum chemical study based on structural variation and π-charge distribution

The transmission of electronic substituent effects along chains of conjugated double bonds has been investigated by analyzing the small structural changes induced by a variable substituent X in the phenyl group of Ph–(CH=CH) n –X molecules (n = 2, 3, and 4). The structures of many such molecules with charged or dipolar substituents have been determined from quantum chemical calculations at the B3LYP/6-311++G** level of theory. The structural variation of the phenyl probe is best represented by a linear combination of the internal ring angles, termed S F PE (n = 2, 3, and 4). Multiple regression analysis of the S F PE parameters using appropriate explanatory variables reveals a composite electronic effect, the main component of which is the field effect of the variable substituent, enhanced by field-induced π-polarization of the polyenic chain. Also important is the role of resonance-induced field effects. An electronegativity term contributes significantly to the structural variation of the phenyl probe in (E)-β-substituted styrenes, Ph–CH=CH–X, but is marginally significant in Ph–(CH=CH)2–X molecules and not significant at all in Ph–(CH=CH)3–X and Ph–(CH=CH)4–X molecules. The structural substituent parameters S F PE2 , S F PE3 , S F PE4 , as well as S F STY from (E)-β-substituted styrenes, are all correlated to each other. However, even though the correlation coefficients are high, it appears unequivocally that the data points corresponding to dipolar substituents and those corresponding to charged groups are aligned along slightly different straight lines. An analysis of π-charge distribution in Ph–(CH=CH) n –X molecules (n = 1–4) has also been carried out. It appears that as the number of double bonds increases, the π-charge transmitted from the variable substituent to the hydrocarbon frame becomes larger, while the π-charge transmitted to the phenyl probe becomes smaller. In each of the three series of Ph–(CH=CH) n –X molecules (n = 2, 3, and 4), the π-charge of the phenyl probe is linked by an excellent nonlinear relationship to the corresponding structural substituent parameter S F PE (n = 2, 3, and 4). The effect of the variable substituent on the geometry of the polyenic chain has been studied by analyzing the alternation of C–C bond lengths along the chain in Ph–(CH=CH)4–X molecules. The alternation is most pronounced and regular when the variable substituent X is an uncharged group, irrespective of whether it is a π-acceptor or a π-donor. For the five strongest resonant substituents in our data set (namely, the charged groups CH2 +, CH2 −(c), NH−, O−, and N2 +), there is a region in the chain where the alternation between adjacent C–C bonds decreases and inverts, a structural feature known as geometric soliton.

Algebraic Cycles on Quadric Sections of Cubics in ℙ4under the Action of Symplectomorphisms

AbstractLetτbe the involution changing the sign of two coordinates in ℙ4. We prove thatτinduces the identity action on the second Chow group of the intersection of aτ-invariant cubic with aτ-invariant quadric hypersurface in ℙ4. LetlτandΠτbe the one- and two-dimensional components of the fixed locus of the involutionτ. We describe the generalized Prymian associated with the projection of aτ-invariant cubic𝓵⊂ P4fromlτontoΠτin terms of the Prymians𝓅2and𝓅3associated with the double covers of two irreducible components, of degree 2 and 3, respectively, of the reducible discriminant curve. This gives a precise description of the induced action of the involutionτon the continuous part of the Chow group CH2(𝓵). The action on the subgroup corresponding to𝓅3is the identity, and the action on the subgroup corresponding to𝓅2is the multiplication by —1.