High Levels Of Incorporation Research Articles

Convenient synthesis of deuterium labelled sesquiterpenes

Sesquiterpenes are an important class of molecules, with roles ranging from pollination and signalling to defense mechanisms. Despite their apparent importance, the limited number of commercial standards has hindered their study and precise quantification. Herein, we report the syntheses of fourteen labelled sesquiterpenes with a high level of deuterium incorporation (>95%) for applications in MS-based studies.

Realizing the Intended Nationally Determined Contribution: The Role of Renewable Energies in Vietnam

This study contributes to the realization of intended nationally determined contributions (INDCs) by analyzing their implications for the energy production system and the economy, and determines the role of renewable energies (RE) in reducing the challenge of committing to the INDCs. The Asia-Pacific Integrated Model/Computable General Equilibrium (AIM/CGE) model was used to assess seven scenarios having the same socioeconomic development but different shares of RE in power generation. By comparing different relative reductions caused by the emission constraints vis-a-vis the business-as-usual (BaU) scenario, the mitigation costs can be estimated. Results show that the economic impact could be reduced by around 55% in terms of welfare loss (from 6.0% to 2.7%) and by around 36% in terms of gross domestic product (GDP) loss (from 3.4% to 2.1%) through the incorporation of high levels of renewable energy. Furthermore, the additional double deployment of wind and SPV to 5.4% and 12.0%, respectively, which currently comprise 43.1% of the renewable energies used in electricity generation, could reduce the GDP loss from 2.1% to 1.9% and reduce the welfare loss from 2.7% to 1.5% in order to achieve a 25.0% GHG emissions reduction. These losses are less than those in the pricing-only scenario (2.1% and 2.3%, respectively).

Bottom-up construction of highly photoactive dye-sensitized titania using Ru(II) and Ir(III) complexes as building blocks

The one-pot co-condensation of tetrabutyl orthotitanate (TBOT) and the neutral Ru(II) N3 dye or the new cationic Ir(III) complex [Ir(ppy)2(3,3′-H2dcbpy)]PF6 have yielded novel hybrid in-situ titanias, which present an exceptional stability against leaching or photodegradation of the coordination dye. The main advantages of this strategy are: i) high dye incorporation level, ii) narrowing band gap and iii) high stability. These materials exhibit much higher photocatalytic activity, under both UV and visible light, not only than the dye-free titania but also than the related dye-sensitized titania prepared by post-synthetic grafting. This in-situ synthetic approach is a promising alternative route to prepare highly stable dye-sensitized materials with great applicability potential.

Oil stabilization of natural peanut butter using food grade polymers

The application of freeze dried hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC) as stabilizers in peanut butter were investigated. These cellulose derivatives were dispersed in water and subsequently freeze dried and chopped to produce a stabilizer that is able to absorb high amounts of oil. Without this templating approach, HPMC and MC had no effect on peanut butter stability and texture. An alternative spray drying approach was attempted, however, it was found that high incorporation levels were required to have any stabilizing effect, which is undesirable. Centrifugal accelerated stability testing showed a significant reduction in oil leakage for samples stabilized with freeze dried HPMC and MC at addition levels as low as 0.2 wt% in peanut butter, while at addition levels of 2.2 wt%, no oil loss was observed. With the addition of >1 wt% HPMC/MC, peanut butters were shelf stable for 6 months or longer. Textural quality of the peanut butter was investigated using a penetration test. Addition of freeze dried HPMC/MC increased sample firmness and adhesiveness which mimicked the properties of traditional peanut butter products stabilized with hydrogenated vegetable oils. Light and scanning electron micrographs showed morphology differences among the stabilizer preparation methods and minimal structural changes in stabilized peanut butter samples. These experiments helped gain insight into the mechanism of oil entrapment and demonstrated the potential of these food-grade polymers as stabilizers in food systems.

Design and Preparation of CO Tolerant Anode Electrocatalysts for PEM Fuel Cells

In this contribution the preparation and the thorough characterization of a novel electrocatalyst support material consisting of a composite of Ti0.7W0.3O2 mixed oxide and activated carbon is presented. A sol-gel based synthesis method optimized for depositing rutile TiO2 with high level of isovalent tungsten incorporation onto activated carbon was elaborated and the process of tungsten incorporation was followed by XRD and in situ XPS measurements. Electron microscopy studies demonstrated that Pt loading of the support by the NaBH4- assisted ethylene-glycol reduction method results in finely dispersed and highly stable nanoparticles. The assessment of the electrochemical properties of the catalyst revealed its enhanced CO tolerance and long term stability when compared to activated carbon supported Pt or state-of-art CO tolerant PtRu catalysts.

Effects of Cu Electroplating Formulas on the Interfacial Microstructures of Sn/Cu Joints

Sn/Cu solder joints serve as electrical pathways and mechanical supports in microelectronic packaging. This study demonstrates that the Cu plating formula has a strong effect on the incorporation of impurities in the Cu deposit and, consequently, affects the microstructural evolution of the Sn/Cu interface. An additive formula with polyethylene glycol (PEG) and chloride ions (Cl−) results in a high-level incorporation of impurities (carbon, oxygen, sulfur, and chlorine) in the Cu deposit. Segregation of impurities to the Sn/Cu interface occurs during thermal aging, which induces the formation of voids and Cu-impurity compounds (CuO, Cu2O, and CuS2) embedded in the Cu6Sn5 and Cu3Sn phase layers, forming an unusual alternating layer structure that is structurally loose and unstable. The addition of bis(3-sulfopropyl) disulfide (SPS) along with PEG and Cl− helps restore the microstructural integrity of the Sn/Cu interface by suppressing the incorporation of impurities. This suppression strongly depends upon the SPS concentration and the PEG molecular weight. The aging temperature also has a significant effect on the microstructural evolution of the Sn/Cu interface, which is determined by the change of the dominant diffusion species.

High-Level Incorporation of Silver in Gold Nanoclusters: Fluorescence Redshift upon Interaction with Hydrogen Peroxide and Fluorescence Enhancement with Herbicide.

High-level incorporation of Ag in Au nanoclusters (NCs) is conveniently achieved by controlling the concentration of Ag(+) in the synthesis of bovine serum albumin (BSA)-protected Au NCs, and the resulting structure is determined to be bimetallic Ag28 Au10-BSA NCs through a series of characterizations including energy-dispersive X-ray spectroscopy, mass spectroscopy, and X-ray photoelectron spectroscopy, together with density functional theory simulations. Interestingly, the Ag28 Au10 NCs exhibit a significant fluorescence redshift rather than quenching upon interaction with hydrogen peroxide, providing a new approach to the detection of hydrogen peroxide through direct comparison of their fluorescence peaks. Furthermore, the Ag28 Au10 NCs are also used for the sensitive and selective detection of herbicide through fluorescence enhancement. The detection limit for herbicide (0.1 nm) is far below the health value established by the U.S. Environmental Protection Agency; such sensitive detection was not achieved by using AuAg NCs with low-level incorporation of Ag or by using the individual metal NCs.

Isotopic Labelling of Functionalised Arenes Catalysed by Iridium(I) Species of the [(cod)Ir(NHC)(py)]PF6 Complex Class

Iridium(I) complexes of the type [(cod)Ir(NHC)(Py)]PF6 have been exposed as efficient catalysts in the area of hydrogen-isotope exchange. More specifically, by an ortho-directed C–H activation process, high levels of deuterium incorporation have been achieved using low levels of catalyst over a range of functionalised aromatic compounds. Additionally, the developed protocol has been extended to include a selected pharmacological target, where chemoselective labelling is observed within such a multifunctional substrate.

F14512, a polyamine-vectorized inhibitor of topoisomerase II, exhibits a marked anti-tumor activity in ovarian cancer

Epithelial ovarian cancer is the fourth cause of death among cancer-bearing women and frequently associated with carboplatin resistance, underlining the need for more efficient and targeted therapies. F14512 is an epipodophylotoxin-core linked to a spermine chain which enters cells via the polyamine transport system (PTS). Here, we investigate this novel concept of vectorization in ovarian cancer. We compared the effects of etoposide and F14512 on a panel of five carboplatin-sensitive or resistant ovarian cancer models. We assessed the incorporation of F17073, a spermine-linked fluorescent probe, in these cells and in 18 clinical samples. We then showed that F14512 exhibits a high anti-proliferative and pro-apoptotic activity, particularly in cells with high levels of F17073 incorporation. Consistently, F14512 significantly inhibited tumor growth compared to etoposide, in a cisplatin-resistant A2780R subcutaneous model, at a dose of 1.25 mg/kg. In addition, ex vivo analysis indicated that 15 out of 18 patients presented a higher F17073 incorporation into tumor cells compared to normal cells. Overall, our data suggest that F14512, a targeted drug with a potent anti-tumor efficacy, constitutes a potential new therapy for highly PTS-positive and platinum-resistant ovarian cancer-bearing patients.

Digestibility of solvent-treated Jatropha curcas kernel by broiler chickens in Senegal.

Jatropha curcas is a drought-resistant shrub belonging to the Euphorbiaceae family. The kernel contains approximately 60% lipid in dry matter, and the meal obtained after oil extraction could be an exceptional source of protein for family poultry farming, in the absence of curcin and, especially, some diterpene derivatives phorbol esters that are partially lipophilic. The nutrient digestibility of J. curcas kernel meal (JKM), obtained after partial physicochemical deoiling was thus evaluated in broiler chickens. Twenty broiler chickens, 6weeks old, were maintained in individual metabolic cages and divided into four groups of five animals, according to a 4 × 4 Latin square design where deoiled JKM was incorporated into grinded corn at 0, 4, 8, and 12% levels (diets 0, 4, 8, and 12J), allowing measurement of nutrient digestibility by the differential method. The dry matter (DM) and organic matter (OM) digestibility of diets was affected to a low extent by JKM (85 and 86% in 0J and 81% in 12J, respectively) in such a way that DM and OM digestibility of JKM was estimated to be close to 50%. The ether extract (EE) digestibility of JKM remained high, at about 90%, while crude protein (CP) and crude fiber (CF) digestibility were largely impacted by JKM, with values closed to 40% at the highest levels of incorporation. J. curcas kernel presents various nutrient digestibilities but has adverse effects on CP and CF digestibility of the diet. The effects of an additional heat or biological treatment on JKM remain to be assessed.

Affordable uniform isotope labeling with 2H, 13C and 15N in insect cells

For a wide range of proteins of high interest, the major obstacle for NMR studies is the lack of an affordable eukaryotic expression system for isotope labeling. Here, a simple and affordable protocol is presented to produce uniform labeled proteins in the most prevalent eukaryotic expression system for structural biology, namely Spodoptera frugiperda insect cells. Incorporation levels of 80% can be achieved for (15)N and (13)C with yields comparable to expression in full media. For (2)H,(15)N and (2)H,(13)C,(15)N labeling, incorporation is only slightly lower with 75 and 73%, respectively, and yields are typically twofold reduced. The media were optimized for isotope incorporation, reproducibility, simplicity and cost. High isotope incorporation levels for all labeling patterns are achieved by using labeled algal amino acid extracts and exploiting well-known biochemical pathways. The final formulation consists of just five commercially available components, at costs 12-fold lower than labeling media from vendors. The approach was applied to several cytosolic and secreted target proteins.

Iridium(I)-catalyzed regioselective C-H activation and hydrogen-isotope exchange of non-aromatic unsaturated functionality.

Isotopic labelling is a key technology of increasing importance for the investigation of new CH activation and functionalization techniques, as well as in the construction of labelled molecules for use within both organic synthesis and drug discovery. Herein, we report for the first time selective iridium-catalyzed CH activation and hydrogen-isotope exchange at the β-position of unsaturated organic compounds. The use of our highly active [Ir(cod)(IMes)(PPh3 )][PF6 ] (cod=1,5-cyclooctadiene) catalyst, under mild reaction conditions, allows the regioselective β-activation and labelling of a range of α,β-unsaturated compounds with differing steric and electronic properties. This new process delivers high levels of isotope incorporation over short reaction times by using low levels of catalyst loading.

Microstructure of ethylcellulose oleogels and its relationship to mechanical properties

Abstract Small deformation rheology was used at a controlled strain of 0.05% and frequency from 1 to 100 Hz to obtain G′, G″, and tan(δ) values for ethylcellulose oleogels of various compositions. Significant increases in both G′ and G″ were noted in oleogels prepared with 100 cP ethylcellulose as compared to 45 cP, yet no significant differences in tan(δ) were observed among gels containing the same type of vegetable oil. Oleogels prepared with increasing polymer concentration showed a significant increase in G′ only when the concentration exceeded 13%. When the surfactant sorbitan monostearate was incorporated at a level of 3.33%, a significant increase in tan(δ) was seen, indicating a decrease in elasticity of these oleogels. Cryo-scanning electron microscopy was successfully utilized to image the internal polymer network of ethylcellulose oleogels, which contained small oil-filled pores of approximately 3.0–4.5 μm in size lying between the interconnected polymer chains. Decreases in pore sizes were observed with increasing polymer concentration, oil unsaturation, and high levels of surfactant incorporation. No significant change in pore size was seen among gels made with different polymer viscosities, signifying an alternate mechanism for changing oleogel hardness. De-oiled ethylcellulose oleogels were also successfully imaged using fluid-phase contact mode atomic force microscopy. The striking similarity in the images obtained by both these methods strongly suggests the morphological features of the oleogels are preserved through the sample preparation procedure. Ethylcellulose xerogel micrographs were shown for the first time, and also contain some regions with pores similar in morphology to those identified in micrographs of the partially de-oiled oleogels.

Bromodeoxyuridine labelling and fluorescence-activated cell sorting of polyamine-transforming bacterioplankton in coastal seawater.

Polyamines (PAs) are a group of nitrogen-rich dissolved organic nitrogen (DON) compounds that are ubiquitously distributed in marine environments. To identify bacteria that are involved in PA transformations, coastal bacterioplankton microcosms were amended with a single PA model compound, i.e. putrescine (PUT) or spermidine (SPD), or with no addition as controls (CTRs). Bromodeoxyuridine (BrdU) was added to all the microcosms to label newly synthesized DNAs. Fluorescence-activated cell sorting (FACS) analysis indicated significant increases in numbers of total cells and cells with both high and low levels of BrdU incorporation in the PUT and SPD microcosms, but not in the CTRs. 16S rDNA pyrotag sequencing of FACS-sorted cells indicated that PUT- and SPD-transforming bacteria were composed similarly of a diverse group of taxa affiliated with Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria (especially Roseobacter of its alpha lineage). Broad taxonomic distribution of PA-transforming bacteria was also indicated by the abundance and distribution of PA transporter gene homologues in a survey of sequenced marine bacterial genomes. Our results suggest that PAs may be common DON substrates for marine bacterioplankton, in line with the hypothesis that bacterially mediated PA transformation accounts for an important proportion of marine DON flux.

An analysis of segregation during horizontal ribbon growth of silicon

A finite-element, thermal-capillary model is applied to study solute segregation in the horizontal ribbon growth of silicon. Results show a complicated redistribution of solute into the growing ribbon, with nearly constant composition in the upper portion of the crystal and high levels of solute incorporation in the lower portion. The redistribution pattern is explained by convective flow patterns and interfacial geometry in the system. Lower values of equilibrium partition coefficient and solute melt diffusivity contribute to more inhomogeneous crystal composition. Faster pull rates lead to more pronounced redistribution of solute in the crystal. Paradoxically, the inhomogeneous concentration levels in HRG ribbon may be beneficial; impurities accumulate towards a narrow bottom portion of the crystal, leaving a majority of the crystal relatively pure.

Dispersing Bacterial Cellulose Nanowhiskers in Polylactides via Electrohydrodynamic Processing

In the present study, hybrid electrospun polylactide (PLA) fibers reinforced with highly dispersed crystalline bacterial cellulose nanowhiskers (BCNW) in solution concentrations up to 15 wt% were developed and characterized. The overall aim was to encapsulate dispersed BCNW in fibers to be later re-dispersed in virgin PLA by melt compounding. Initially, the suitability of three different solvents [1,1,1,3,3,3-hexafluoro-2-propanol (HFP), acetone–chloroform and chloroform/polyethylene glycol (PEG)] for fiber production was evaluated and solutions containing 5 wt% BCNW were used to generate electrospun hybrid PLA fibers. These fibers presented a homogeneous morphology, as assessed by scanning electron microscopy, and transmission electron microscopy images demonstrated that BCNW were well distributed along the fibers. Differential scanning calorimetry analyses showed that the incorporation of PEG into the fibers resulted in a Tg drop due to a plasticization effect and decreased thermal stability as a result of low interactions between the matrix and the BCNW. Subsequently, fibers were produced from the selected solutions (HFP and acetone–chloroform) containing up to 15 wt% BCNW. As a result of the great increase in the viscosity of the solutions, lower solids contents were required, leading to a better dispersion and incorporation degree of BCNW within the fibers. HFP was found to be a more suitable solvent, since higher incorporation levels were estimated by X-ray diffraction and improved matrix–filler interactions were suggested by a slight increase in the Tg of the fibers.

DNA Polymerase V Kinetics Support the Instructive Nature of an Oxidized Abasic Lesion in Escherichia coli

Translesion synthesis past an oxidized abasic site, 2-deoxyribonolactone, in Escherichia coli results in high levels of dG incorporation and is dependent upon DNA polymerase V (Pol V). Kinetic experiments performed here affirm that Pol V preferentially incorporates dG opposite 2-deoxyribonolactone (L). Pol V discriminates between dG and dA on the basis of the apparent KD, suggesting that L provides instructive structural information to the enzyme despite lacking a Watson-Crick base.

Effect of incorporation of decorticated pigeon pea (<em>Cajanus cajan</em>) protein isolate on functional, baking and sensory characteristics of Wheat (<em>Triticum aesitivum</em>) biscuit

This study was undertaken with the objectives of using the decorticated pigeon pea protein isolate in the development of protein rich-biscuit, suitable for general and specific nutritional purposes and to study the effect of incorporation of pigeon pea protein isolate on the sensory evaluation and quality of biscuit produced. Decorticated Pigeon Pea protein Isolate (DPPI) was incorporated in wheat (Triticum aesitivum) flour (WF, extraction rate 72%), for making fortified biscuit. Ratios of DPPI in wheat flour were adjusted to protein levels of 15, 20 and 25%, respectively. Rheological and functional properties as well as proximate composition, nutritive value and sensory characteristics for the biscuit produced were assessed. The gluten quantity (dry and wet) and falling number of wheat flour were significantly (p#0.05) decreased with the incorporation of DPPI from 10.25 to 7.6%; from 31.2 to 22.5% and from 657 to 443 sec., for 0,15, 20 and 25% protein levels, respectively.Water Retention Capacity (WRC), Bulk Density (BD) and Fat Absorption Capacity (FAC) were obtained. Addition of DPPI resulted in an increase in water absorption which was found to be ranged from 66.7 to 71.0%; dough development time from 4.5 to 7.3 min and dough stability 1.7 to 5.8 min. Biscuit supplemented with DPPI showed significant increase (p#0.05) in ash, protein with high level of incorporation and significant decrease (p#0.05) in carbohydrates and caloric values when biscuit wheat was supplemented with high level of DPPI. Incorporation of DPPI showed no significant differences (p#0.05) on biscuit spread ratios compared to wheat biscuit (control). Biscuit with 15% protein level was found to be superior in all its sensory characteristics compared to the other blends.

Atmospheric pressure chemical vapour deposition of vanadium arsenide thin films via the reaction of VCl4 or VOCl3 with tBuAsH2

Thin films of vanadium arsenide were deposited via the dual-source atmospheric pressure chemical vapour deposition reactions of VCl4 or VOCl3 with tBuAsH2. Using the vanadium precursor VCl4, films were deposited at substrate temperatures of 550–600°C, which were black-gold in appearance and were found to be metal-rich with high levels of chlorine incorporation. The use of VOCl3 as the vanadium source resulted in films being deposited between 450 and 600°C and, unlike when using VCl4, were silver in appearance. The films deposited using VOCl3 demonstrated vanadium to arsenic ratios close to 1:1, and negligible chlorine incorporation. Films deposited using either vanadium precursor were identified as VAs using powder X-ray diffraction and possessed borderline metallic/semiconductor resistivities.

The effect of deuteration on the structure of bacterial cellulose

In vivo generated deuterated bacterial cellulose, cultivated from 100% deuterated glycerol in D2O medium, was analyzed for deuterium incorporation by ionic liquid dissolution and 2H and 1H nuclear magnetic resonance (NMR). A solution NMR method of the dissolved cellulose was used to determine that this bacterial cellulose had 85% deuterium incorporation. Acetylation and 1H and 2H NMR of deuterated bacterial cellulose indicated near equal deuteration at all sites of the glucopyranosyl ring except C-6 which was partly deuterated. Despite the high level of deuterium incorporation no significant differences in the molecular and morphological properties were observed for the deuterated and protio bacterial cellulose samples. The highly deuterated bacterial cellulose presented here can be used as a model substrate for studying cellulose biopolymer properties via future small angle neutron scattering (SANS) studies.