CH OH Research Articles

Strategies and challenges with the microbial conversion of methanol to high‐value chemicals

As alternatives to traditional fermentation substrates, methanol (CH3 OH), carbon dioxide (CO2 ) and methane (CH4 ) represent promising one-carbon (C1) sources that are readily available at low-cost and share similar metabolic pathway. Of these C1 compounds, methanol is used as a carbon and energy source by native methylotrophs, and can be obtained from CO2 and CH4 by chemical catalysis. Therefore, constructing and rewiring methanol utilization pathways may enable the use of one-carbon sources for microbial fermentations. Recent bioengineering efforts have shown that both native and nonnative methylotrophic organisms can be engineered to convert methanol, together with other carbon sources, into biofuels and other commodity chemicals. However, many challenges remain and must be overcome before industrial-scale bioprocessing can be established using these engineered cell refineries. Here, we provide a comprehensive summary and comparison of methanol metabolic pathways from different methylotrophs, followed by a review of recent progress in engineering methanol metabolic pathways in vitro and in vivo to produce chemicals. We discuss the major challenges associated with establishing efficient methanol metabolic pathways in microbial cells, and propose improved designs for future engineering.

Can N, S Cocoordination Promote Single Atom Catalyst Performance in CO2 RR? Fe-N2 S2 Porphyrin versus Fe-N4 Porphyrin.

Single atom catalysts (SACs) are promising electrocatalysts for CO2 reduction reaction (CO2 RR), in which the coordination environment plays a crucial role in intrinsic catalytic activity. Taking the regular Fe porphyrin (Fe-N4 porphyrin) as a probe, the study reveals that the introduction of opposable S atoms into N coordination (Fe-N2 S2 porphyrin) allows for an appropriate electronic structural optimization on active sites. Owing to the additional orbitals around the Fermi level and the abundant Fe orbital occupation after S substitution, N, S cocoordination can effectively tune SACs and thus facilitating protonation of intermediates during CO2 RR. CO2 RR mechanisms lead to possible C1 products via two-, six-, and eight-electron pathways are systematically elucidated on Fe-N4 porphyrin and Fe-N2 S2 porphyrin. Fe-N4 porphyrin yields the most favorable product of HCOOH with a limiting potential of -0.70V. Fe-N2 S2 porphyrin exhibits low limiting potentials of -0.38 and -0.40V for HCOOH and CH3 OH, respectively, surpassing those of most Cu-based catalysts and SACs. Hence, the N, S cocoordination might provide better catalytic environment than regular N coordination for SACs in CO2 RR. This work demonstrates Fe-N2 S2 porphyrin as a high-performance CO2 RR catalyst, and highlights N, S cocoordination regulation as an effective approach to fine tune high atomically dispersed electrocatalysts.

Azide-Coordination in Homometallic Dinuclear Lanthanide(III) Complexes Containing Nonequivalent Lanthanide Metal Ions: Zero-Field SMM Behavior in the Dysprosium Analogue.

A series of homometallic dinuclear lanthanide complexes containing nonequivalent lanthanide metal centers [Ln2(LH2)(LH)(CH3OH)(N3)]·xMeOH·yH2O [1, Ln = DyIII, x = 0, y = 2; 2, Ln = TbIII, x = 1, y = 1] have been synthesized [LH4 = 6-((bis(2-hydroxyethyl)amino)-N'-(2-hydroxybenzylidene)picolinohydrazide] and characterized. The dinuclear assembly contains two different types of nine-coordinated lanthanide centers, because the nonequivalent binding of the azide co-ligand as well as the varying coordination of the deprotonated Schiff base ligand. Detailed magnetic studies have been performed on the complexes 1 and 2. Complex 1 and its diluted analogue (15%) are zero-field SMMs with effective energy barriers (Ueff) of magnetization reversal equal to 59(3) K and 66(3) K and relaxation times of τ0 = 10(4) × 10-6 s and 10(4) × 10-8 s, respectively. On the other hand, complex 2 shows a field-induced SMM behavior. Combined ab initio and density functional theory calculations were performed to explain the experimental findings and to unravel the nature of the magnetic anisotropy, exchange-coupled spectra, and magnetic exchange interactions between the two lanthanide centers.

Rational Design and Effective Control of Gold-Based Bimetallic Electrocatalyst for Boosting CO2 Reduction Reaction: A First-Principles Study.

Electrochemical CO2 reduction reaction (CO2 RR) is an effective strategy converting CO2 to value-added products. Au is regarded as an efficient catalyst for electrochemical reduction of CO2 to CO, and the introduction of Pd can tune CO2 RR properties due to its strong affinity to CO. Herein, Au-Pd bimetallic electrocatalysts with different metal ratio were firstly investigated on CO2 RR mechanism by using density functional theory. The Au monolayer over Pd substrate and single Pd atom on Au(111) were found to show better CO2 RR selectivity against hydrogen evolution reaction (HER). Based on this, various single-atom catalysts on Au(111) and core-shell models with top Au monolayer were designed to study their CO2 RR performance. The results indicated that Pt, Cu, and Rh substrates below Au monolayer could enhance the activity and selectivity for CO production compared to pure Au, in which the limiting potential reduced from -0.74 to -0.63, -0.69, and -0.71 V, respectively. The single Pd embedded on Au(111) could adjust the adsorption strength, which provided an effective site to receive and further reduce CO to CH3 OH and CH4 at a low limiting potential of -0.61 V, and also avoided catalyst poisoning due to the over-strengthened CO adsorption caused by high Pd proportion on the surface. In addition, the adsorption energy of COOH was observed as a better CO2 RR reactivity descriptor than the common CO adsorption when establishing scaling relationship, which could avoid the fitting error caused by intermediate physisorption of CO.

Radical Chain Breaking Bis(ortho-organoselenium) Substituted Phenolic Antioxidants.

The presence of a chalcogen atom at the ortho-position of phenols enhances their radical chain-breaking activity. Here, a copper(I)-catalyzed reaction of 2,6-dibromo- and 2,6-diiodophenols with diorganodiselenides has been studied for the introduction of two organoselenium substituents at both ortho-positions of the phenolic radical chain-breaking antioxidants, which afforded 2,6-diorganoseleno-substituted phenols in 80-92% yields having electron-donating CH3 , and electron-withdrawing CN and CHO functionalities. Additionally, 2,6-diiodophenols with electron-withdrawing CHO and CN groups also afforded novel 5,5'-selenobis(4-hydroxy-3-(phenylselanyl)benzaldehyde) and 5,5'-selenobis(4-hydroxy-3-(phenylselanyl)benzonitrile) consisting of three selenium and two phenolic moieties along with 2,6-diorganoseleno-substituted phenols has been synthesized. The electron-withdrawing CHO group has been reduced by sodium borohydride to the electron-donating alcohol CH2 OH group, which is desirable for efficient radical quenching activity of phenols. The developed copper-catalyzed reaction conditions enable the installation of two-arylselenium group ortho to phenolic radical chain-breaking antioxidants, which may not be possible by conventional organolithium-bromine exchange methods due to the sluggish reactivity of trianions (dicarba and phenoxide anion), which are generated by the reaction of organolithium with 2,6-dibromophenols, with diorganodiselenides. The antioxidant activities of the synthesized bis and tris selenophenols have been accessed by DPPH, thiol peroxides, and singlet oxygen quenching assay. The radical quenching antioxidant activity has been studied for the synthesized compounds by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The bis-selenophenols show comparable radical deactivating activity, while tris seleno-bisphenols show higher radical deactivating activity than α-tocopherol. Furthermore, the tris seleno-bisphenol shows comparable peroxide decomposing activity with ebselen molecules.

Lewis Acid Strength of Interfacial Metal Sites Drives CH3 OH Selectivity and Formation Rates on Cu-Based CO2 Hydrogenation Catalysts.

CH3 OH formation rates in CO2 hydrogenation on Cu-based catalysts sensitively depend on the nature of the support and the presence of promoters. In this context, Cu nanoparticles supported on tailored supports (highly dispersed M on SiO2 ; M=Ti, Zr, Hf, Nb, Ta) were prepared via surface organometallic chemistry, and their catalytic performance was systematically investigated for CO2 hydrogenation to CH3 OH. The presence of Lewis acid sites enhances CH3 OH formation rate, likely originating from stabilization of formate and methoxy surface intermediates at the periphery of Cu nanoparticles, as evidenced by metrics of Lewis acid strength and detection of surface intermediates. The stabilization of surface intermediates depends on the strength of Lewis acid M sites, described by pyridine adsorption enthalpies and 13 C chemical shifts of -OCH3 coordinated to M; these chemical shifts are demonstrated here to be a molecular descriptor for Lewis acid strength and reactivity in CO2 hydrogenation.

Solvent-Dependent Adsorption-Driven Mechanism for MOFs-Based Yolk-Shell Nanostructures.

Metal-organic frameworks (MOFs)-based yolk-shell nanostructures have drawn enormous attention recently due to their multifunctionality. However, the regulations of the size and morphology of yolk-shell nanostructures are still limited by the unclear formation mechanism. Herein, we first demonstrated a solvent-dependent adsorption-driven mechanism for synthesizing yolk-shelled MOFs-based nanostructures coated with mesoporous SiO2 shells (ZIF-8@mSiO2 ) with tunable size and morphology. The selective and competitive adsorption of methanol (CH3 OH) and water (H2 O) on ZIF-8 core were found to have decisive effects on inducing the morphology evolution of yolk-shell nanostructures. The obtained yolk-shelled ZIF-8@mSiO2 nanostructures show great promise in generating acoustic cavitation effect for sonodynamic cancer therapy in vitro. We believe that this work will not only help us to design novel MOFs-based yolk-shell nanostructures, but also promote the widespread application of MOFs materials.

Site Sensitivity of Interfacial Charge Transfer and Photocatalytic Efficiency in Photocatalysis: Methanol Oxidation on Anatase TiO2 Nanocrystals.

Photocatalytic oxidation of methanol on various anatase TiO2 nanocrystals was studied by in situ and time-resolved characterizations and DFT calculations. Surface site and resulting surface adsorbates affect the surface band bending/bulk-to-surface charge migration processes and interfacial electronic structure/interfacial charge transfer processes. TiO2 nanocrystals predominantly enclosed by the {001} facets expose a high density of reactive fourfold-coordinated Ti sites (Ti4c ) at which CH3 OH molecules dissociate to form the CH3 O adsorbate (CH3 O(a)Ti4c ). CH3 O(a)Ti4c localized density of states are almost at the valence band maximum of TiO2 surface, facilitating the interfacial hole transfer process; CH3 O(a)Ti4c with a high coverage promotes upward surface band bending, facilitating bulk-to-surface hole migration. CH3 O(a)Ti4c exhibits the highest photocatalytic oxidation rate constant. TiO2 nanocrystals enclosed by the {001} facets are most active in photocatalytic methanol oxidation.

Vinylidene, allenylidene, cyclic oxycarbene, and η2-alkyne complexes from reactions of (η5-C5Me5)OsCl(PPh3)2 with alkynes and alkynols

Reactions of Cp*OsCl(PPh3)2 (Cp* = pentamethylcyclopentadienyl) with alkynes and alkynols are described. Treatment of Cp*OsCl(PPh3)2 with phenylacetylene and trimethylsilylacetylene gave the vinylidene complexes Cp*OsCl(=C=CHPh)(PPh3) and Cp*OsCl(=C=CH2)(PPh3), respectively. Treatment of Cp*OsCl(PPh3)2 with the internal alkyne dimethyl acetylenedicarboxylate produced the η2-alkyne complex Cp*OsCl(η2-MeO2C≡CCO2Me)(PPh3). Treatment of Cp*OsCl(PPh3)2 with the propargylic alcohol HC≡CC(OH)Ph2 gave the osmium allenylidene complex Cp*OsCl(=C = C=CPh2)(PPh3). The outcomes of the reactions of Cp*OsCl(PPh3)2 with ω-alkynols HC≡C(CH2)nOH are dependent on the length of the -(CH2)n- linker. The reaction with 3-butyn-1-ol produced the cyclic oxycarbene complex Cp*OsCl{=C(CH2)3O}(PPh3) exclusively. The reactions with 4-pentyn-1-ol produced a mixture of the hydroxyalkyl vinylidene complex Cp*OsCl{=C=CH(CH2)3OH}(PPh3) and the cyclic oxycarbene complex Cp*OsCl{=C(CH2)4O}(PPh3) in about 10:1 molar ratio. The reaction with 5-hexyn-1-ol gave exclusively the hydroxyalkyl vinylidene complex Cp*OsCl{=C=CH(CH2)4OH}(PPh3).

Coupling of Cu(100) and (110) Facets Promotes Carbon Dioxide Conversion to Hydrocarbons and Alcohols

Copper can efficiently electro-catalyze carbon dioxide reduction to C2+ products (C2 H4 , C2 H5 OH, n-propanol). However, the correlation between the activity and active sites remains ambiguous, impeding further improvements in their performance. The facet effect of copper crystals to promote CO adsorption and C-C coupling and consequently yield a superior selectivity for C2+ products is described. We achieve a high Faradaic efficiency (FE) of 87 % and a large partial current density of 217 mA cm-2 toward C2+ products on Cu(OH)2 -D at only -0.54 V versus the reversible hydrogen electrode in a flow-cell electrolyzer. With further coupled to a Si solar cell, record-high solar conversion efficiencies of 4.47 % and 6.4 % are achieved for C2 H4 and C2+ products, respectively. This study provides an in-depth understanding of the selective formation of C2+ products on Cu and paves the way for the practical application of electrocatalytic or solar-driven CO2 reduction.

Glutathione Protects the Developing Heart from Defects and Global DNA Hypomethylation Induced by Prenatal Alcohol Exposure.

Fetal alcohol spectrum disorder (FASD) is caused by prenatal alcohol exposure (PAE), the intake of ethanol (C2 H5 OH) during pregnancy. Features of FASD cover a range of structural and functional defects including congenital heart defects (CHDs). Folic acid and choline, contributors of methyl groups to one-carbon metabolism (OCM), prevent CHDs in humans. Using our avian model of FASD, we have previously reported that betaine, another methyl donor downstream of choline, prevents CHDs. The CHD preventions are substantial but incomplete. Ethanol causes oxidative stress as well as depleting methyl groups for OCM to support DNA methylation and other epigenetic alterations. To identify more compounds that can safely and effectively prevent CHDs and other effects of PAE, we tested glutathione (GSH), a compound that regulates OCM and is known as a "master antioxidant." Quail embryos injected with a single dose of ethanol at gastrulation exhibited congenital defects including CHDs similar to those identified in FASD individuals. GSH injected simultaneously with ethanol not only prevented CHDs, but also improved survival and prevented other PAE-induced defects. Assays of hearts at 8days (HH stage 34) of quail development, when the heart normally has developed 4-chambers, showed that this single dose of PAE reduced global DNA methylation. GSH supplementation concurrent with PAE normalized global DNA methylation levels. The same assays performed on quail hearts at 3days (HH stage 19-20) of development, showed no difference in global DNA methylation between controls, ethanol-treated, GSH alone, and GSH plus ethanol-treated cohorts. GSH supplementation shows promise to inhibit effects of PAE by improving survival, reducing the incidence of morphological defects including CHDs, and preventing global hypomethylation of DNA in heart tissues.

Use Of Natural Gas Become a Petrochemical with Zeolite Catalyst

Methane is a hydrocarbon compound that can be used for various purposes. Currently, methane is widely used as fuel, and continues to be developed as a synthetic gas material and petrochemical products that have added value, one of which is formaldehyde. This study aimed to study the partial catalytic oxidation reaction of methane to formaldehyde using MoO3/zeolite as a catalyst. Reactant gas stream consisting of pure O2 and CH 4 were contacted with a rate ratio of 1:20, put into Fixed Bed Reactor therein contained 30 grams of catalyst MoO3/zeolite, and the pressure was maintained at 1 atm. The temperature and flow rate of the incoming reactant gas were used as variables. The main product produced was formaldehyde, besides that there were also CH3 OH, CO, CO2, H2O. The results were analyzed using Gas Chromatography, so it was known that the converted methane was 5.18% and the volume fraction of formaldehyde formed was 1.46%.

Selective, Catalytic Oxidations of C–H Bonds in Polyethylenes Produce Functional Materials with Enhanced Adhesion

Summary The synthesis of functional and processable polyethylenes from simple vinyl monomers with controlled molecular weights and architectures has been a grand challenge of polymer chemistry. Post-polymerization modification of the homopolymers of ethylene is attractive for this purpose but has been hampered by the lack of efficient methods for the selective functionalization of C–H bonds in polyolefins. We report the selective, catalytic oxidation of C–H bonds in commodity polyethylenes with varying molecular weights and architectures. Remarkably, the functionalized materials, even at low levels of functionalization, exhibit physical properties that are absent in unmodified polyolefins, such as strong adhesion and the ability to be painted with common waterborne latex paint. Such observations indicate that selectively modified polyethylenes as described here may help to transform existing commodity plastics into more valuable and potentially more sustainable materials.

Selective Ethanol Oxidation Reaction at the Rh-SnO2 Interface.

Direct ethanol fuel cells (DEFCs) are regarded as an attractive power source with high energy density, bio-renewability, and convenient storage and transportation. However, the anodic reaction of DEFCs, that is, the ethanol oxidation reaction (EOR), suffers from poor efficiency due to the low selectivity to CO2 (C1 pathway) and high selectivity to CH3 COOH (C2 pathway). In this study, the selective EOR to CO2 can be achieved at the Rh-SnO2 interface in SnO2 -Rh nanosheets (NSs). The optimized catalyst of 0.2SnO2 -Rh NSs/C exhibits excellent alkaline EOR performance with a mass activity of 213.2 mA mgRh -1 and a Faraday efficiency of 72.8% for the C1 pathway, which are 1.7 and 1.9 times higher than those of Rh NSs/C. Mechanism studies indicate that the strong synergy at the Rh-SnO2 interface significantly promotes the breaking of CC bond of C2 H5 OH to form CO2 , and facilitates oxidation of the poisonous intermediates (* CO and * CH3 ) to suppress the deactivation of the catalyst. This work not only provides a highly selective, active, and stable catalyst for the EOR, but also promotes fundamental research for the design of efficient catalysts via interface modification.

Electrospray ionization tandem mass spectrometry of deprotonated dihydrobenzofuran neolignans.

Although dihydrobenzofuran neolignans (DBNs) display a wide diversity of biological activities, the identification of their in vivo metabolites using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) remains a challenge to be overcome. Recently, ESI-MS/MS data of protonated DBNs have been reported, but they were shown to be limited due to the scarcity of diagnostic ions. The gas-phase fragmentation pathways of a series of biologically active synthetic benzofuran neolignans (BNs) and DBNs were elucidated by means of negative ESI accurate-mass tandem and sequential mass spectrometry, and thermochemical data estimated using computational chemistry and the B3LYP/6-31+G(d,p) model. Deprotonated DBNs produced more diagnostic product ions than the corresponding protonated molecules. Moreover, a series of odd-electron product ions (radical anions) were detected, which has not been reported for protonated DBNs. Direct C2 H3 O2 • elimination from the precursor ion (deprotonated molecule) only occurred for the BNs and can help to distinguish these compounds from the DBNs. The mechanism through which the [M - H - CH3 OH]- ion is formed is strongly dependent on specific structural features. The negative ion mode provides much more information than the positive ion mode (at least one diagnostic product ion was detected for all the analyzed compounds) and does not require the use of additives to produce the precursor ions (deprotonated molecules).

Determination of an effective method of Citrus aurantifolia lime and Citrus lemon varieties plant explants sterilization for in vitro introduction into the culture

Potted citrus plants are in constant demand, but the propagation of such plants requires the use of a winter greenhouse and several well-developed mother plants to obtain planting material. The use of microclonal propagation can accelerate the production of seed material though it requires detailed development of in vitro cultivation techniques. The aim of the research was to study the effectiveness of sterilizing substances and methods of sterilization on the yield of viable micro shoots of lime plants (Citrus aurantifolia) as well as Meyer and Jubilee lemon varieties and their growth in vitro. The research was conducted in the interdepartmental "Biotechnological Laboratory" of the Agrobiotechnological Faculty of Bila Tserkva NAU. The source material was microshoots from lime plants (Citrus aurantifolia), and lemon varieties (Citrus lemon) Meyer and Jubilee. The objects of the study were selected according to the diversity of genotypes, development type and varietal characteristics. The possibility of using different parts of plants for reproduction is a feature of in vitro culture. We used microshoots with a bud in our research. To neutralize the exogenous bacterial and fungal microflora, we used 70 % ethanol solution C2 H5 OH, sodium hypochlorite 5 %, 15 % solution of hydrogen peroxide H2 O2 , sulema (0.1) and washed the material in sterile water (for 5–10 min) under several schemes. The study revealed the influence of different sterilization regimes for obtaining sterile explants and the introduction into plant culture of explants of the species of lime Citrus aurantifolia as well as Meyer and Jubilee lemon varieties. It was found that the use of step sterilization using 2.5 % solutions of sodium hypochlorite gives a high percentage of sterile viable material – 27.7 %, which is significantly higher than in other variants of the experiment. Key words: microshoots, lime, sterile material, micropropagation, sterilization, hydrogen peroxide, viability of explants.

Investigation of the Correlations between Amino Acids, Amino Acid Mixtures and Dipeptides by Terahertz Spectroscopy

Terahertz (THz) spectroscopy is regarded as a professional technology to probe collective molecular vibrational modes and intensity of bio–molecules, which is potential to analyze amino acids and short peptides. In this study, THz spectroscopy is utilized to investigate the correlations of glycine (Gly), Serine (Ser), amino acid mixtures of Gly/Ser, and dipeptides (GS and SG) in the frequency range of 0.3–2.5 THz. The results manifest that the collective molecular vibrational intensity of Ser is larger than Gly, implying that the hydroxyl methyl group (–CH2–OH) on the side chain of Ser exhibits larger motions than that of –H in Gly. Additionally, the THz spectra of amino acid mixtures of Gly/Ser fit the linear addition of the individual amino acid absorption spectrum. Herein, the THz spectra of dipeptide GS and its isomer SG are distinguished according to the different collective molecular vibrations produced by the terminal groups on the carbon skeleton. Compared to physical amino acid mixtures of Gly/Ser, the dipeptides exhibit diverse THz spectra, indicating that the different collective vibrational modes are caused by peptide bonds and terminal groups. These solid evidences confirm that THz spectroscopy can be availably used to analyze the correlations of amino acids, amino acid mixtures, and dipeptides, as well as to identify dipeptide and its isomer from molecular level.

Tertiary Amine-Ethylene Glycol Based Tandem CO2 Capture and Hydrogenation to Methanol: Direct Utilization of Post-Combustion CO2.

Carbon dioxide capture using tertiary amines in ethylene glycol solvent was performed under ambient conditions. Subsequently, the CO2 captured as alkyl carbonate salts was successfully hydrogenated to methanol, in the presence of H2 gas and Ru-Macho-BH catalyst. A comprehensive series of tertiary amines were selected for the integrated capture and conversion process. While most of these amines were effective for CO2 capture, tetramethylethylenediamine (TMEDA) and tetramethylbutanediamine (TMBDA) provided the best CH3 OH yields. Deactivation of the base due to side reactions was significantly minimized and substantial base regeneration was observed. The proposed system was also highly efficient for CO2 capture from a gas mixture containing 10 % CO2 , as found in flue gases, followed by tandem conversion to CH3 OH. We postulate that such high boiling tertiary amine-glycol systems as dual capture and hydrogenation solvents are promising for the realization of a sustainable and carbon-neutral methanol economy in a scalable process.

Impact of thermal processing and storage on fatty acid composition and cholesterol oxidation of canned traditional low-fat meat product of India

The effects of thermal processing/canning and storage on fatty acids (FAs) contents and cholesterol oxidation of traditional low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India were studied. Goshtaba is a restructured traditional meat product of J&K; India prepared from meat emulsion with added fat (20–30%), salt, spices and condiments and cooked in the curd based gravy. The FAs composition i.e. SFAs, MUFAs, PUFAs and TFAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The dominant FAs were C16:0 (palmitic acid) and C18:0 (stearic acid) among SFAs, C18:1n9 (n-9-oleic acid) among MUFAs, C18:2n6 (n-6- linoleic acid) followed by C18:3n3 (n-3-α-linolenic acid) among PUFAs and C18:1t11 (vaccenic acid) among the TFAs in all products. The cholesterol content decreased significantly after thermal processing in all products (P < 0.05) and maximum decrease was observed in high-fat goshtaba (HFC). During storage significant decrease was observed in cholesterol up to 6th month, thereafter showed non-significant difference. The cholesterol oxidation products (COPs) determined were 7-β–OH–ch, 5-ch-3β-ol-7-one and 25-OH-ch. After, thermal processing two COPs (7-β–OH–ch and 5-ch-3β-ol-7-one) were produced in all goshtaba products. During storage there was formation of 25-OH-ch, increase in 7-β–OH–ch and decrease in 5-ch-3β-ol-7-one and maximum levels were observed in HFC. The results concluded that processing and storage had no significant effect on the FAs composition of all goshtaba products including HFC. However, maximum reduction in cholesterol and formation of COPs were observed in HFC and might be due to the large surface exposure of fat.

Angular emission distribution of O 1s photoelectrons of uniaxially oriented methanol

The angular distribution of O 1s photoelectrons emitted from uniaxially oriented methanol is studied experimentally and theoretically. We employed circularly polarized photons of an energy of hν = 550 eV for our investigations. We measured the three-dimensional photoelectron angular distributions of methanol, with the CH3–OH axis oriented in the polarization plane, by means of cold target recoil ion momentum spectroscopy. The experimental results are interpreted by single active electron calculations performed with the single center method. A comparative theoretical study of the respective molecular-frame angular distributions of O 1s photoelectrons of CO, performed for the same photoelectron kinetic energy and for a set of different internuclear distances, allows for disentangling the role of internuclear distance and the hydrogen atoms of methanol as compared to carbon monoxide.