Intermolecular acetaldehyde and dimethoxymethane formation mechanisms via ethenol and methoxymethylene precursors in reactions of atomic carbon with methanol: a computational study

Atomic carbon, a reactive intermediate abundant in the interstellar medium (ISM) can participate in various energetically demanding reactions in its extremely long living (69 min) first excited singlet state ((1)D). Several studies on reactions of oxygen containing species with carbon atoms have been reported, however mechanistic details of the title reaction remain obscure. We report here quantum chemical studies on reactions of methanol with (3)P and (1)D carbon atoms at the CCSD(T)/cc-pVTZ level of theory, with which experimentally well known facile CO production, intermolecular acetaldehyde formation, and intermolecular dimethoxymethane production mechanisms are explained. Energetics of the fragmentation, O-H insertion, C-H insertion, and O-C insertion channels on the triplet and singlet surfaces are studied. The CO production mechanism by C ((1)D) is identified as an oxygen abstraction and a triplet PES seems non-operative. Presenting novel features for the intermolecular reaction channels, current findings may be applicable to C + ROR reactions.     

Phage Displayed HBV Core Antigen with Immunogenic Activity

Hepatitis B is a major public health problem worldwide, which may lead to chronic liver diseases such as cirrhosis and hepatocellular carcinoma. The hepatitis B core antigen (HBcAg) is one of the major viral proteins, which forms the inner core of hepatitis B virus (HBV) particles. In this study, filamentous bacteriophage M13 was genetically modified to display the polypeptides of HBcAg in order to develop an alternative carrier system. HBcAg gene was inserted into the minor coat protein (pIII) gene of M13, and HBcAg was expressed on the phage surface as a whole protein. Antigenicity and immunogenicity of HBcAg were tested by immunizing BALB/c mice three times with HBcAg-displaying recombinant phages. After successful immunization, one of the mice with high antibody titer to HBcAg was selected for fusion, and four monoclonal antibodies specific for HBcAg were developed. This result showed that HBcAg-displaying recombinant bacteriophages are immunogenic and can potentially be used for the development of monoclonal antibodies.     

Investigation of in vitro efficiency of magnetic nanoparticle-conjugated <Superscript>125</Superscript>I-uracil glucuronides in adenocarcinoma cells

Modification of the magnetic properties of a drug can be used to direct the drug to the desired site, enhancing its therapeutic effectiveness and reducing side effects. In this study, surface-modified magnetic nanoparticles were immobilized with uracil glucuronide derivatives and then labeled with I-125. The morphology, structure, and composition of the magnetic particles were examined by TEM, SEM, VSM, and XRD. The particles sizes were about 50 nm. The labeling yield was 93.8% for uracil-O-glucuronide-immobilized magnetic particles and 95.0% for uracil-N-glucuronide-immobilized magnetic particles. The cell incorporation rates of N- and O-glucuronides were higher than those of uracil. The incorporation rates of uracil-, O-glucuronide-, and N-glucuronide-conjugated magnetic particles were all high. The cell incorporation rates of ligand-conjugated magnetic particles increased under a magnetic field.     

In vitro evaluation of radiolabeled (125I) methanol extracts of yarrow in cell lines of MCF-7, PC-3, A-549 and Caco-2

Nowadays, cancer is still the second leading cause of death all over the world. Therefore, natural products which have anticancer and antitumor properties are come into prominence. Achillea family is known with anticancer and antitumor activity. Yarrow which has over a hundred bioactive compounds is a member of Achillea family. In current study; components of yarrow which was obtained after methanol extraction and purification were radiolabeled with ¹²⁵I and effects of these radiolabeled components on the cells were examined with using Caco-2, MCF-7, A-549, PC-3 cell lines. As a result of these studies, seven peaks were obtained and the highest radiolabeling yield was calculated for ¹²⁵I radiolabeled Peak 7 (95.00 ± 7.07, n = 4). To screen the biological properties of these radiolabeled peaks at determined cell lines, our ongoing effort was to evaluate incorporation percentage with time dependent. Furthermore, ¹²⁵I-Peak 7 had highest incorporation ratio for whole cell lines and its incorporation percentage was increased with time dependent. Results of these in vitro studies were compatible with previous in vivo studies and traditional use of yarrow plants.     

Generation of acyl anion equivalents from acylphosphonates via phosphonate-phosphate rearrangement: a highly practical method for cross-benzoin reaction

[reactions: see text] Acylphosphonates are potent acyl anion precursors that generate acyl anion equivalents under the promotion of cyanide anion via phosphonate-phosphate rearrangement. These anions readily react with aldehydes to provide cross-benzoin products. In this way it is possible to synthesize a variety of aromatic-aromatic, aromatic-aliphatic, and aliphatic-aromatic benzoins. Moreover the reaction of benzoylphosphonate with potent electrophile 2,2,2-trifluoroacetophenone provided the corresponding aldehyde-ketone coupling product in high yield.     

Competing pathways in the [2 + 2] cycloadditions of cyclopentyne and benzyne. A DFT and ab initio study

The [2 + 2] cycloadditions of cyclopentyne and benzyne to ethylene are explored at the B3LYP and CASSCF levels, supplemented by CCSD(T) and CAS-MP2 calculations at the stationary points. The biradical path in the benzyne system is computed to be about 4.1 kcal/mol lower than the concerted path, consistent with the experimentally observed loss of original stereochemistry in this cycloaddition. However, computations fail to confirm the 99% stereoretention in the corresponding reaction of cyclopentyne. The concerted and biradical paths in the latter reaction are found to involve nearly isoenergetic barriers, thus predicting only about 75% stereoretention. More sophisticated theoretical methods seem to be needed to resolve the issue in the cyclopentyne system.     

Anionic and cationic polymerization of norbornadiene in hydrocarbon

Norbornadiene (NBD) has been successfully polymerized in benzene solvent in high yield (up to 100%) using AlCl₃ as initiator. Anionic polymerization of the same compound was achieved using butyllithium as initiator. According to the IR and NMR data, both polymers have a 2,6-disubstituted nortricyclene structure. The cationic polymerization gave an amorphous polymer; the anionic polymerization resulted in the formation of a crystalline product showing higher stability.     

Advances in Fibrin-Based Materials in Wound Repair: A Review

The first bioprocess that occurs in response to wounding is the deterrence of local hemorrhage. This is accomplished by platelet aggregation and initiation of the hemostasis cascade. The resulting blood clot immediately enables the cessation of bleeding and then functions as a provisional matrix for wound healing, which begins a few days after injury. Here, fibrinogen and fibrin fibers are the key players, because they literally serve as scaffolds for tissue regeneration and promote the migration of cells, as well as the ingrowth of tissues. Fibrin is also an important modulator of healing and a host defense system against microbes that effectively maintains incoming leukocytes and acts as reservoir for growth factors. This review presents recent advances in the understanding and applications of fibrin and fibrin-fiber-incorporated biomedical materials applied to wound healing and subsequent tissue repair. It also discusses how fibrin-based materials function through several wound healing stages including physical barrier formation, the entrapment of bacteria, drug and cell delivery, and eventual degradation. Pure fibrin is not mechanically strong and stable enough to act as a singular wound repair material. To alleviate this problem, this paper will demonstrate recent advances in the modification of fibrin with next-generation materials exhibiting enhanced stability and medical efficacy, along with a detailed look at the mechanical properties of fibrin and fibrin-laden materials. Specifically, fibrin-based nanocomposites and their role in wound repair, sustained drug release, cell delivery to wound sites, skin reconstruction, and biomedical applications of drug-loaded fibrin-based materials will be demonstrated and discussed.