One-Pot Synthesis of Stable Phosphorus Ylides Using CH-Acid Compounds

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and di-tert-butyl acetylendicarboxylate, in the presence of antron, dimedone, indandion, and 3,5-dimethylbarbituric acid. These stable ylides exist in a solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

Explicit dispersion relation for strongly nonlinear flexural waves using the homotopy analysis method

Nonlinear Dynamics - Using the homotopy analysis method, we present an explicit frequency-versus-wavenumber nonlinear dispersion relation for a flexural elastic beam. In our analysis, we employ the...     

Synthesis and reactions of 2,2,2-trihaloethyl α-hydroxyiminobenzylphosphonates. The influence of the ester group on the chemistry of phosphonates

Arbuzov reactions of diethyl 2,2,2-trihaloethyl phosphites ( 3 ) with benzoyl chloride afforded ethyl 2,2,2-trihaloethyl benzoylphosphonates ( 4 ). The reactions of 4 with NH₂OH.HCl led to the formation of methyl benzoate and ethyl methyl H-phosphonate as a result of alcoholysis of 4 , followed by alkoxy group exchange. Methanol solutions of benzoylphosphonates 4 were found by ³¹P NMR spectroscopy to contain considerable proportions of hemiacetals, 7 , which undergo base-catalyzed C P bond cleavage. The formation of hemiacetals from benzoylphosphonates 4 is suppressed in 2-propanol, and in this solvent the corresponding oximes 2 could be obtained in good yields. Reactions of methyl benzoylphosphonochloridate ( 10 ) with 2,2,2-trihaloethanols, in CH₂Cl_2, gave methyl 2,2,2-trihaloethyl benzoylphosphonates ( 11 ) which could be converted directly to oximes 12 by NH₂OH.HCl in a one-pot procedure. In contrast to the previously studied dimethyl (E)-α-hydroxyiminobenzylphosphonate, which underwent thermal Beckmann rearrangement to afford N-benzoylphosphoramidates, both (E) and (Z)-trihaloethyl esters 2 and 12 underwent fragmentation to benzonitrile and to the corresponding dialkyl hydrogen phosphate, reflecting the increased electrophilicity of the phosphorus in these compounds. Demethylation of methyl esters 12 was effected smoothly by iodide or bromide ions to yield benzoylphosphonate salts 15 , which in turn were converted to oxime salts 14 by treatment with hydroxylamine. In contrast, attempted deethylation of ethylesters 2 in refluxing acetonitrile led to benzonitrile and pyrophosphate type product as indicated by ³¹P spectroscopic examination of the reaction mixture. Oxime salts 14 behaved similarly when heated. Acidification of lithium 2,2,2-trifluoroethyl α-hydroxyiminobenzylphosphonate ( 14a ) gave the corresponding hydrogen trifluoroethyl phosphonate ( 19a ). The fragmentation of 19a in 0.6 N ethanolic hydrogen chloride to ethyl trifluoroethyl hydrogen phosphate and benzonitrile at room temperature had a T_1/2 value of approx 18 hours, which is greater by a factor of 2 than that of the corresponding methyl ester. When the fragmentation of 19 was carried out in solvent mixtures of either water with methanol or 2-propanol, or methanol with tbutanol, the composition of the solvents was reflected in the products, indicating a dissociative type mechanism, involving metaphosphate as reactive intermediates.     

Changes in Whey Proteome between Mediterranean and Murrah Buffalo Colostrum and Mature Milk Reflect Their Pharmaceutical and Medicinal Value

Milk represents an integrated meal for newborns; its whey protein is rich in many health beneficial components and proteins. The current study aimed to investigate the differences between colostrum and mature milk from Mediterranean and Murrah buffaloes using labeled proteomics and bioinformatics tools. In the current work, LC-MS/MS analysis led to identification of 780 proteins from which 638 were shared among three independent TMT experiments. The significantly changed proteins between the studied types were analyzed using gene ontology enrichment and KEGG pathways, and their interactions were generated using STRING database. Results indicated that immunological, muscular development and function, blood coagulation, heme related, neuronal, translation, metabolic process, and binding proteins were the main terms. Overall, colostrum showed higher levels of immunoglobulins, myosins, actin, neurofascin, syntaxins, thyroglobulins, and RNA-binding proteins, reflecting its importance in the development and activity of immunological, muscular, cardiac, neuronal, and thyroid systems, while lactoferrin and ferritin were increased in mature milk, highlighting its role in iron storage and hemoglobin formation.     

Effect of Native Reservoir State and Oilfield Operations on Clay Mineral Surface Chemistry

An understanding of clay mineral surface chemistry is becoming critical as deeper levels of control of reservoir rock wettability via fluid–solid interactions are sought. Reservoir rock is composed of many minerals that contact the crude oil and control the wetting state of the rock. Clay minerals are one of the minerals present in reservoir rock, with a high surface area and cation exchange capacity. This is a first-of-its-kind study that presents zeta potential measurements and insights into the surface charge development process of clay minerals (chlorite, illite, kaolinite, and montmorillonite) in a native reservoir environment. Presented in this study as well is the effect of fluid salinity, composition, and oilfield operations on clay mineral surface charge development. Experimental results show that the surface charge of clay minerals is controlled by electrostatic and electrophilic interactions as well as the electrical double layer. Results from this study showed that clay minerals are negatively charged in formation brines as well as in deionized water, except in the case of chlorite, which is positively charged in formation water. In addition, a negative surface charge results from oilfield operations, except for operations at a high alkaline pH range of 10–13. Furthermore, a reduction in the concentrations of Na, Mg, Ca, and bicarbonate ions does not reverse the surface charge of the clay minerals; however, an increase in sulfate ion concentration does. Established in this study as well, is a good correlation between the zeta potential value of the clay minerals and contact angle, as an increase in fluid salinity results in a reduction of the negative charge magnitude and an increase in contact angle from 63 to 102 degree in the case of chlorite. Lastly, findings from this study provide vital information that would enhance the understanding of the role of clay minerals in the improvement of oil recovery.     

A Modified Contact Angle Measurement Process to Suppress Oil Drop Spreading and Improve Precision

Static contact angle measurement is a widely applied method for wettability assessment. Despite its convenience, it suffers from errors induced by contact angle hysteresis, material heterogeneity, and other factors. This paper discusses the oil drop spreading phenomenon that was frequently observed during contact angle measurements. Experimental tests showed that this phenomenon is closely related to surfactants in the surrounding phase, the remaining oil on the rock surface, and oil inside the surrounding phase. A modified contact angle measurement process was proposed. In the modified method, deionized water was used as the surrounding phase, and a rock surface cleaning step was added. Subsequent measurements showed a very low chance of oil drop spreading and improved precision. A further comparison study showed that, when the surrounding phase was deionized water, the measured contact angle values tended to be closer to intermediate-wet conditions compared to the values measured in clean surfactant solutions. This difference became more significant when the surface was strongly water-wet or strongly oil-wet. As a result, the developed process has two prerequisites: that the in-situ contact angle values inside surfactant solutions are not required, and that the wettability alteration induced by the surfactant solution is irreversible.     

Immunoadjuvant and Humoral Immune Responses of Garlic (Allium sativum L.) Lectins upon Systemic and Mucosal Administration in BALB/c Mice

Dietary food components have the ability to affect immune function; following absorption, specifically orally ingested dietary food containing lectins can systemically modulate the immune cells and affect the response to self- and co-administered food antigens. The mannose-binding lectins from garlic (Allium sativum agglutinins; ASAs) were identified as immunodulatory proteins in vitro. The objective of the present study was to assess the immunogenicity and adjuvanticity of garlic agglutinins and to evaluate whether they have adjuvant properties in vivo for a weak antigen ovalbumin (OVA). Garlic lectins (ASA I and ASA II) were administered by intranasal (50 days duration) and intradermal (14 days duration) routes, and the anti-lectin and anti-OVA immune (IgG) responses in the control and test groups of the BALB/c mice were assessed for humoral immunogenicity. Lectins, co-administered with OVA, were examined for lectin-induced anti-OVA IgG response to assess their adjuvant properties. The splenic and thymic indices were evaluated as a measure of immunomodulatory functions. Intradermal administration of ASA I and ASA II had showed a four-fold and two-fold increase in anti-lectin IgG response, respectively, vs. the control on day 14. In the intranasal route, the increases were 3-fold and 2.4-fold for ASA I and ASA II, respectively, on day 50. No decrease in the body weights of animals was noticed; the increases in the spleen and thymus weights, as well as their indices, were significant in the lectin groups. In the adjuvanticity study by intranasal administration, ASA I co-administered with ovalbumin (OVA) induced a remarkable increase in anti-OVA IgG response (~six-fold; p < 0.001) compared to the control, and ASA II induced a four-fold increase vs. the control on day 50. The results indicated that ASA was a potent immunogen which induced mucosal immunogenicity to the antigens that were administered intranasally in BALB/c mice. The observations made of the in vivo study indicate that ASA I has the potential use as an oral and mucosal adjuvant to deliver candidate weak antigens. Further clinical studies in humans are required to confirm its applicability.     

Removal of the Harmful Nitrate Anions from Potable Water Using Different Methods and Materials,including Zero-Valent Iron

Drinking water containing nitrate ions at a higher concentration level of more than 10 mg/L, according to the World Health Organization (WHO), poses a considerable peril to humans. This danger lies in its reduction of nitrite ions. These ions cause methemoglobinemia during the oxidation of hemoglobin into methemoglobin. Many protocols can be applied to the remediation of nitrate ions from hydra solutions such as Zn metal and amino sulfonic acid. Furthermore, the electrochemical process is a potent protocol that is useful for this purpose. Designing varying parameters, such as the type of cathodic electrode (Sn, Al, Fe, Cu), the type of electrolyte, and its concentration, temperature, pH, and current density, can give the best conditions to eliminate the nitrate as a pollutant. Moreover, the use of accessible, functional, and inexpensive adsorbents such as granular ferric hydroxide, modified zeolite, rice chaff, chitosan, perlite, red mud, and activated carbon are considered a possible approach for nitrate removal. Additionally, biological denitrification is considered one of the most promising methodologies attributable to its outstanding performance. Among these powerful methods and materials exist zero-valent iron (ZVI), which is used effectively in the deletion process of nitrate ions. Non-precious synthesis pathways are utilized to reduce the Fe²⁺ or Fe³⁺ ions by borohydride to obtain ZVI. The structural and morphological characteristics of ZVI are elucidated using UV–Vis spectroscopy, zeta potential, XRD, FE-SEM, and TEM. The adsorptive properties are estimated through batch experiments, which are achieved to control the feasibility of ZVI as an adsorbent under the effects of Fe⁰ dose, concentration of NO₃⁻ ions, and pH. The obtained literature findings recommend that ZVI is an appropriate applicant adsorbent for the remediation of nitrate ions.     

Preparation and Physicochemical Characterization of Gelatin–Aldehyde Derivatives

The present study aimed at preparing novel free-radical scavenging and water-soluble compounds derived from gelatin. Specifically, gelatin–syringaldehyde, gelatin–anisaldehyde, and gelatin–vanillin were synthesized and thoroughly studied for their physicochemical properties. In particular, the compounds were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Notably, as demonstrated by thermogravimetry and differential scanning calorimetry, all three derivatives exhibited higher thermal stability than gelatin itself. Free-radical scavenging activities of the examined compounds were explored by (i) a standard spectrophotometric ABTS assay and (ii) an assay of oxidative degradation of hyaluronic acid monitored by rotational viscometry. We found that gelatin and gelatin–syringaldehyde demonstrated the highest efficacy in scavenging ^•OH radicals, whereas gelatin–anisaldehyde was the least effective. The efficacy of scavenging alkyloxy- and alkylperoxy-type free radicals via hydrogen-atom-transferring property was in the following order: gelatin > gelatin–vanillin > gelatin–syringaldehyde > gelatin–anisaldehyde. Electron-donor properties determined using the ABTS assay revealed the following order in one-electron reduction of ABTS^•+: gelatin > gelatin–anisaldehyde > gelatin–vanillin > gelatin–syringaldehyde.