Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

PubMed

Taha, M O; Aiedeh, K M; Al-Hiari, Y; Al-Khatib, H

2005-10-01

The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

Metalloprobes: Synthesis, Characterization, and Potency of a Novel Gallium(III) Complex in Human Epidermal Carcinoma Cells

PubMed Central

Harpstrite, Scott E.; Prior, Julie; Rath, Nigam P.; Sharma, Vijay

2009-01-01

Multidrug resistance (MDR) mediated by overexpression of the MDR1 gene product, P-glycoprotein (Pgp), represents one of the best characterized barriers to chemotherapeutic treatment in cancer and may be a pivotal factor in progression of Alzheimer’s disease (AD). Thus, agents capable of probing Pgp-mediated transport could be beneficial in biomedical imaging. Herein, we synthesized and structurally characterized a gallium(III) complex of the naphthol-Schiff base ligand (5). The crystal structure revealed octahedral geometry for the metallodrug. Cytotoxicity profiles of 5 were evaluated in KB-3-1 (Pgp−) and KB-8-5 (Pgp+) human epidermal carcinoma cell lines. Compared with an LC50 (the half-maximal cytotoxic concentration) value of 1.93 μM in drug-sensitive (Pgp−) cells, the gallium(III) complex 5 demonstrated an LC50 value > 100 μM in drug-resistant (Pgp+) cells, thus indicating that 5 was recognized by the Pgp as its substrate, thereby extruded from the cells and sequestered away from their cytotoxic targets. Radiolabeled analogues of 5 could be beneficial in noninvasive imaging of Pgp-mediated transport in vivo. PMID:17617464

Ionic liquids screening for desulfurization of natural gasoline by liquid-liquid extraction.

PubMed

Likhanova, Natalya V; Guzmán-Lucero, Diego; Flores, Eugenio A; García, Paloma; Domínguez-Aguilar, Marco A; Palomeque, Jorge; Martínez-Palou, Rafael

2010-11-01

Seventy five ionic liquids (ILs) were tested as a sequestering agent of sulfured compounds in natural gasoline (NG). Desulphurization of NG was performed by means of liquid-liquid extraction method at room temperature and atmospheric pressure. Experimental ILs containing imidazolium, pyridinium, and ammonium cations along with organic and inorganic anions were synthesized conventionally and under microwave and sonochemical conditions. The effect of the molecular structure of ILs on the desulfurization efficiency of NG with high sulfur content was evaluated. Analysis indicated that the anion type played a more important role than the cation on the desulphurization process. ILs based on halogen-ferrates and halogen-aluminates exhibited the highest efficiency in sulfur removal, and their efficiency is further improved when there is an excess of metallic salt in a ratio of at least 1:1.3 during the synthesis of the corresponding IL. An explanation for the ability of metallic ILs to remove sulfur-containing compounds from natural gasoline based on the ratio of the ionic charge to the atomic radius is proposed. Furthermore, a method to recover and reuse water-sensitive to halogenated precursors is described.

Social and cultural influences on management for carbon sequestration on US family forestlands: a literature synthesis

Treesearch

A. Paige Fischer; Susan Charnley

2010-01-01

Nonindustrial private—or "family"—forests hold great potential for sequestering carbon and have received much attention in discussions about forestry-based climate change mitigation. However, little is known about social and cultural influences on owners' willingness to manage for carbon and respond to policies designed to encourage carbon-oriented...

A COMPOUND PRODUCED BY FRUIGIVOROUS TEPHRITIDAE (DIPTERA) LARVAE PROMOTES OVIPOSITION BEHAVIOR BY THE BIOLOGICAL CONTROL AGENT Diachasmimorpha longicaudata (Ashmead) (HYMENOPTERA: BRACONIDAE)

USDA-ARS?s Scientific Manuscript database

Tephritid parasitoids use fruit-derived chemical cues and the vibrations that result from larval movements to locate hosts sequestered inside fruit. However, compounds produced by the larvae themselves have not been previously described nor their significance to parasitoid foraging determined. We co...

A compound produced by Fruigivorous Tephritidae (Diptera) larvae promotes oviposition behavior by the biological control agent Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

USDA-ARS?s Scientific Manuscript database

Tephritid fruit fly parasitoids use fruit-derived chemical cues and the vibrations that result from larval movements to locate hosts sequestered inside fruit. However, compounds produced by the larvae themselves have not been previously described nor their significance to parasitoid foraging determi...

Sequestering ability of butylated hydroxytoluene, propyl gallate, resveratrol, and vitamins C and E against ABTS, DPPH, and hydroxyl free radicals in chemical and biological systems.

PubMed

Soares, Daniele G; Andreazza, Ana C; Salvador, Mirian

2003-02-12

The antioxidant capacity of butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-p-cresol), propyl gallate (3,4,5-trihydroxybenzoic acid n-propyl ester), resveratrol (trans-3,4',5-trihydroxystilbene), and vitamins C (l-ascorbic acid) and E [(+)-alpha-tocopherol] was studied in chemical and biological systems. The chemical assays evaluated the capacity of these antioxidants to sequester 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.) and 1,1 diphenyl-2-picrylhydrazyl (DPPH.). A new colorimetric method to determine hydroxyl radical scavenging is also described. The biological tests use the eucaryotic cells of Saccharomyces cerevisiae treated with the antioxidants in the presence of the stressing agents apomorphine, hydrogen peroxide, and paraquat dichloride (methylviologen; 1,1'-dimethyl-4,4'-bipyridinium dichloride). The results in chemical systems showed that all of the antioxidants were able to significantly inhibit the oxidation of beta-carotene by hydroxyl free radicals. The assays in yeast showed that the antioxidant activity of the tested compounds depended on the stressing agent used and the mechanism of action of the antioxidant.

Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

DOEpatents

Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

2017-03-21

A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

MCAT is not required for in vitro polyketide synthesis in a minimal actinorhodin polyketide synthase from Streptomyces coelicolor.

PubMed

Matharu, A L; Cox, R J; Crosby, J; Byrom, K J; Simpson, T J

1998-12-01

It has been proposed that Streptomyces malonyl CoA: holo acyl carrier protein transacylases (MCATs) provide a link between fatty acid and polyketide biosynthesis. Two recent studies have provided evidence that the presence of MCAT is essential for polyketide synthesis to proceed in reconstituted minimal polyketide synthases (PKSs). In contrast to this, we previously showed that the holo acyl carrier proteins (ACPs) from type II PKSs are capable of catalytic self-malonylation in the presence of malonyl CoA, which suggests that MCAT might not be necessary for polyketide biosynthesis. We reconstituted a homologous actinorhodin (act) type II minimal PKS in vitro. When act holo-ACP is present in limiting concentrations, MCAT is required by the synthase complex in order for polyketide biosynthesis to proceed. When holo-ACP is present in excess, however, efficient polyketide synthesis proceeds without MCAT. The rate of polyketide production increases with holo-ACP concentration, but at low ACP concentration or equimolar AC:KS:CLF (KS, ketosynthase; CLF, chain length determining factor) concentrations this rate is significantly lower than expected, indicating that free holo-ACP is sequestered by the KS/CLF complex. The rate of polyketide biosynthesis is dictated by the ratio of holo-ACP to KS and CLF, as well as by the total protein concentration. There is no absolute requirement for MCAT in polyketide biosynthesis in vitro, although the role of MCAT during polyketide synthesis in vivo remains an open question. MCAT might be responsible for the rate enhancement of malonyl transfer at very low free holo-ACP concentrations or it could be required to catalyse the transfer of malonyl groups from malonyl CoA to sequestered holo-ACP.

A synthesis of the science on forests and carbon for U.S. Forests

Treesearch

Michael G. Ryan; Mark E. Harmon; Richard A. Birdsey; Christian P. Giardina; Linda S. Heath; Richard A. Houghton; Robert B. Jackson; Duncan C. McKinley; James F. Morrison; Brian C. Murray; Diane E. Pataki; Kenneth E. Skog

2010-01-01

Forests play an important role in the U.S. and global carbon cycle, and carbon sequestered by U.S. forest growth and harvested wood products currently offsets 12-19% of U.S. fossil fuel emissions. The cycle of forest growth, death, and regeneration and the use of wood removed from the forest complicate efforts to understand and measure forest carbon pools and flows....

Synthesis, Structure and Antitumour Properties of a New 1,2-Propylenediaminetetraacetate-Ruthenium(III) Compound

PubMed Central

Vilaplana, R.; Romero, M. A.; Quirós, M.; Salas, J. M.

1995-01-01

A novel complex formed by ruthenium (III) and the sequestering ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been synthetized and characterized. The structure of the monomeric compound, studied by X-ray diffraction , shows an almost symmetric octahedral geometry around the metal ion, with two chlorine atoms in a cis conformation. The antitumour activity against a variety of murine and human cancers is reported. PMID:18472768

Niemann-Pick C disease and mobilization of lysosomal cholesterol by cyclodextrin

PubMed Central

Vance, Jean E.; Karten, Barbara

2014-01-01

Niemann-Pick type C (NPC) disease is a lysosomal storage disease in which endocytosed cholesterol becomes sequestered in late endosomes/lysosomes (LEs/Ls) because of mutations in either the NPC1 or NPC2 gene. Mutations in either of these genes can lead to impaired functions of the NPC1 or NPC2 proteins and progressive neurodegeneration as well as liver and lung disease. NPC1 is a polytopic protein of the LE/L limiting membrane, whereas NPC2 is a soluble protein in the LE/L lumen. These two proteins act in tandem and promote the export of cholesterol from LEs/Ls. Consequently, a defect in either NPC1 or NPC2 causes cholesterol accumulation in LEs/Ls. In this review, we summarize the molecular mechanisms leading to NPC disease, particularly in the CNS. Recent exciting data on the mechanism by which the cholesterol-sequestering agent cyclodextrin can bypass the functions of NPC1 and NPC2 in the LEs/Ls, and mobilize cholesterol from LEs/Ls, will be highlighted. Moreover, the possible use of cyclodextrin as a valuable therapeutic agent for treatment of NPC patients will be considered. PMID:24664998

Situ formation of apatite for sequestering radionuclides and heavy metals

DOEpatents

Moore, Robert C.

2003-07-15

Methods for in situ formation in soil of a permeable reactive barrier or zone comprising a phosphate precipitate, such as apatite or hydroxyapatite, which is capable of selectively trapping and removing radionuclides and heavy metal contaminants from the soil, while allowing water or other compounds to pass through. A preparation of a phosphate reagent and a chelated calcium reagent is mixed aboveground and injected into the soil. Subsequently, the chelated calcium reagent biodegrades and slowly releases free calcium. The free calcium reacts with the phosphate reagent to form a phosphate precipitate. Under the proper chemical conditions, apatite or hydroxyapatite can form. Radionuclide and heavy metal contaminants, including lead, strontium, lanthanides, and uranium are then selectively sequestered by sorbing them onto the phosphate precipitate. A reducing agent can be added for reduction and selective sequestration of technetium or selenium contaminants.

A specific scenario for the origin of life and the genetic code based on peptide/oligonucleotide interdependence.

PubMed

Griffith, Robert W

2009-12-01

Among various scenarios that attempt to explain how life arose, the RNA world is currently the most widely accepted scientific hypothesis among biologists. However, the RNA world is logistically implausible and doesn't explain how translation arose and DNA became incorporated into living systems. Here I propose an alternative hypothesis for life's origin based on cooperation between simple nucleic acids, peptides and lipids. Organic matter that accumulated on the prebiotic Earth segregated into phases in the ocean based on density and solubility. Synthesis of complex organic monomers and polymerization reactions occurred within a surface hydrophilic layer and at its aqueous and atmospheric interfaces. Replication of nucleic acids and translation of peptides began at the emulsified interface between hydrophobic and aqueous layers. At the core of the protobiont was a family of short nucleic acids bearing arginine's codon and anticodon that added this amino acid to pre-formed peptides. In turn, the survival and replication of nucleic acid was aided by the peptides. The arginine-enriched peptides served to sequester and transfer phosphate bond energy and acted as cohesive agents, aggregating nucleic acids and keeping them at the interface.

Performance of an electrochemical carbon monoxide monitor in the presence of anesthetic gases.

PubMed

Dunning, M; Woehlck, H J

1997-11-01

The passage of volatile anesthetic agents through accidentally dried CO2 absorbents in anesthesia circuits can result in the chemical breakdown of anesthetics with production of greater than 10000 ppm carbon monoxide (CO). This study was designed to evaluate a portable CO monitor in the presence of volatile anesthetic agents. Two portable CO monitors employing electrochemical sensors were tested to determine the effects of anesthetic agents, gas sample flow rates, and high CO concentrations on their electrochemical sensor. The portable CO monitors were exposed to gas mixtures of 0 to 500 ppm CO in either 70% nitrous oxide, 1 MAC concentrations of contemporary volatile anesthetics, or reacted isoflurane or desflurane (containing CO and CHF3) in oxygen. The CO measurements from the electrochemical sensors were compared to simultaneously obtained samples measured by gas chromatography (GC). Data were analyzed by linear regression. Overall correlation between the portable CO monitors and the GC resulted in an r2 value >0.98 for all anesthetic agents. Sequestered samples produced an exponential decay of measured CO with time, whereas stable measurements were maintained during continuous flow across the sensor. Increasing flow rates resulted in higher CO readings. Exposing the CO sensor to 3000 and 19000 ppm CO resulted in maximum reported concentrations of approximately 1250 ppm, with a prolonged recovery. Decrease in measured concentration of the sequestered samples suggests destruction of the sample by the sensor, whereas a diffusion limitation is suggested by the dependency of measured value upon flow. Any value over 500 ppm must be assumed to represent dangerous concentrations of CO because of the non-linear response of these monitors at very high CO concentrations. These portable electrochemical CO monitors are adequate to measure CO concentrations up to 500 ppm in the presence of typical clinical concentrations of anesthetics.

Salinomycin kills cancer stem cells by sequestering iron in lysosomes

NASA Astrophysics Data System (ADS)

Mai, Trang Thi; Hamaï, Ahmed; Hienzsch, Antje; Cañeque, Tatiana; Müller, Sebastian; Wicinski, Julien; Cabaud, Olivier; Leroy, Christine; David, Amandine; Acevedo, Verónica; Ryo, Akihide; Ginestier, Christophe; Birnbaum, Daniel; Charafe-Jauffret, Emmanuelle; Codogno, Patrice; Mehrpour, Maryam; Rodriguez, Raphaël

2017-10-01

Cancer stem cells (CSCs) represent a subset of cells within tumours that exhibit self-renewal properties and the capacity to seed tumours. CSCs are typically refractory to conventional treatments and have been associated to metastasis and relapse. Salinomycin operates as a selective agent against CSCs through mechanisms that remain elusive. Here, we provide evidence that a synthetic derivative of salinomycin, which we named ironomycin (AM5), exhibits a more potent and selective activity against breast CSCs in vitro and in vivo, by accumulating and sequestering iron in lysosomes. In response to the ensuing cytoplasmic depletion of iron, cells triggered the degradation of ferritin in lysosomes, leading to further iron loading in this organelle. Iron-mediated production of reactive oxygen species promoted lysosomal membrane permeabilization, activating a cell death pathway consistent with ferroptosis. These findings reveal the prevalence of iron homeostasis in breast CSCs, pointing towards iron and iron-mediated processes as potential targets against these cells.

Colestipol hydrochloride prophylaxis of diarrhea during pelvic radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stryker, J.A.; Chung, C.K.; Layser, J.D.

1983-02-01

Thirty-three patients were randomized prior to pelvic radiotherapy to receive the bile acid-sequestering resin colestipol hydrochloride, 5 grams qid, during the entire time of their therapy or diphenoxylate hydrochloride and atropine sulfate 2.5-20 mg per day (control) if they experienced diarrhea. The colestipol patients also took diphenoxylate if they had diarrhea. The patients in the colestipol group often experienced nausea, vomiting, and abdominal cramps and 8 were forced to discontinue the drug. There was no difference in the weekly stool frequency between the colestipol and the control patients but the colestipol patients who took at least 50% of the prescribedmore » dose required fewer diphenoxylate tablets than the controls. The data suggest that colestipol hydrochloride is not of value in preventing radiation-induced diarrhea because of the side effects associated with the drug, but the theory on which the use of bile acid-sequestering agents is based may be correct.« less

Sevelamer and other anion-exchange resins in the prevention and treatment of hyperphosphataemia in chronic renal failure.

PubMed

Wrong, Oliver; Harland, Clive

2007-01-01

Sevelamer, or more precisely 'sevelamer hydrochloride', is a weakly basic anion-exchange resin in the chloride form that was introduced in 1997 for the treatment of the hyperphosphataemia of patients with end-stage renal failure, usually those on long-term haemodialysis. The rationale for this therapy was that sevelamer would sequester phosphate within the gastrointestinal tract, so preventing its absorption and enhancing its faecal excretion. Over the succeeding years, large numbers of patients have been treated with sevelamer, and it has fulfilled expectations in helping to control the hyperphosphataemia of end-stage renal failure. However, it is only one of many anion-exchange resins that could be used for this purpose, some of which are currently available for clinical use and are much less costly than sevelamer. Theoretical considerations suggest that some of these other resins might be at least as efficient as sevelamer in sequestering phosphate in the gastrointestinal tract. Neither sevelamer, nor any of these other agents, has been submitted to a proper metabolic balance study to measure the amount of phosphate sequestered by the resin in the bowel, and without this information it is impossible to judge which is the ideal resin for this purpose. Copyright 2007 S. Karger AG, Basel.

The chemistry of poisons in amphibian skin.

PubMed Central

Daly, J W

1995-01-01

Poisons are common in nature, where they often serve the organism in chemical defense. Such poisons either are produced de novo or are sequestered from dietary sources or symbiotic organisms. Among vertebrates, amphibians are notable for the wide range of noxious agents that are contained in granular skin glands. These compounds include amines, peptides, proteins, steroids, and both water-soluble and lipid-soluble alkaloids. With the exception of the alkaloids, most seem to be produced de novo by the amphibian. The skin of amphibians contains many structural classes of alkaloids previously unknown in nature. These include the batrachotoxins, which have recently been discovered to also occur in skin and feathers of a bird, the histrionicotoxins, the gephyrotoxins, the decahydroquinolines, the pumiliotoxins and homopumiliotoxins, epibatidine, and the samandarines. Some amphibian skin alkaloids are clearly sequestered from the diet, which consists mainly of small arthropods. These include pyrrolizidine and indolizidine alkaloids from ants, tricyclic coccinellines from beetles, and pyrrolizidine oximes, presumably from millipedes. The sources of other alkaloids in amphibian skin, including the batrachotoxins, the decahydroquinolines, the histrionicotoxins, the pumiliotoxins, and epibatidine, are unknown. While it is possible that these are produced de novo or by symbiotic microorganisms, it appears more likely that they are sequestered by the amphibians from as yet unknown dietary sources. PMID:7816854

2,3-Dihydroxybenzoic acid amides of tetraazaalkanes and tetaaza cycloalkanes

DOEpatents

Weitl, Frederick L. [Martinez, CA; Raymond, Kenneth N. [Berkeley, CA

1980-01-01

A compound of the formula: ##STR1## wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO.sub.3 H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes.

Hydrogen peroxide modified sodium titanates with improved sorption capabilities

DOEpatents

Nyman, May D [Albuquerque, NM; Hobbs, David T [North Augusta, SC

2009-02-24

The sorption capabilities (e.g., kinetics, selectivity, capacity) of the baseline monosodium titanate (MST) sorbent material currently being used to sequester Sr-90 and alpha-emitting radioisotopes at the Savannah River Site are significantly improved when treated with hydrogen peroxide; either during the original synthesis of MST, or, as a post-treatment step after the MST has been synthesized. It is expected that these peroxide-modified MST sorbent materials will have significantly improved sorption capabilities for non-radioactive cations found in industrial processes and waste streams.

Process for preparing 2,3-dihydroxybenzoic acid amides of tetraazaalkanes and cycloalkanes

DOEpatents

Weitl, Frederick L.; Raymond, Kenneth N.

1985-01-01

A compound of the formula: ##STR1## wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO.sub.3 H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes.

The structural basis of transferrin sequestration by transferrin-binding protein B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calmettes, Charles; Alcantara, Joenel; Yu, Rong-Hua

2012-03-28

Neisseria meningitidis, the causative agent of bacterial meningitis, acquires the essential element iron from the host glycoprotein transferrin during infection through a surface transferrin receptor system composed of proteins TbpA and TbpB. Here we present the crystal structures of TbpB from N. meningitidis in its apo form and in complex with human transferrin. The structure reveals how TbpB sequesters and initiates iron release from human transferrin.

Ixodes scapularis Tick Cells Control Anaplasma phagocytophilum Infection by Increasing the Synthesis of Phosphoenolpyruvate from Tyrosine.

PubMed

Cabezas-Cruz, Alejandro; Espinosa, Pedro J; Obregón, Dasiel A; Alberdi, Pilar; de la Fuente, José

2017-01-01

The obligate intracellular pathogen, Anaplasma phagocytophilum , is the causative agent of life-threatening diseases in humans and animals. A. phagocytophilum is an emerging tick-borne pathogen in the United States, Europe, Africa and Asia, with increasing numbers of infected people and animals every year. It is increasingly recognized that intracellular pathogens modify host cell metabolic pathways to increase infection and transmission in both vertebrate and invertebrate hosts. Recent reports have shown that amino acids are central to the host-pathogen metabolic interaction. In this study, a genome-wide search for components of amino acid metabolic pathways was performed in Ixodes scapularis , the main tick vector of A. phagocytophilum in the United States, for which the genome was recently published. The enzymes involved in the synthesis and degradation pathways of the twenty amino acids were identified. Then, the available transcriptomics and proteomics data was used to characterize the mRNA and protein levels of I. scapularis amino acid metabolic pathway components in response to A. phagocytophilum infection of tick tissues and ISE6 tick cells. Our analysis was focused on the interplay between carbohydrate and amino acid metabolism during A. phagocytophilum infection in ISE6 cells. The results showed that tick cells increase the synthesis of phosphoenolpyruvate (PEP) from tyrosine to control A. phagocytophilum infection. Metabolic pathway analysis suggested that this is achieved by (i) increasing the transcript and protein levels of mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), (ii) shunting tyrosine into the tricarboxylic acid (TCA) cycle to increase fumarate and oxaloacetate which will be converted into PEP by PEPCK-M, and (iii) blocking all the pathways that use PEP downstream gluconeogenesis (i.e., de novo serine synthesis pathway (SSP), glyceroneogenesis and gluconeogenesis). While sequestering host PEP may be critical for this bacterium because it cannot actively carry out glycolysis to produce PEP, excess of this metabolite may be toxic for A. phagocytophilum . The present work provides a more comprehensive view of the major amino acid metabolic pathways involved in the response to pathogen infection in ticks, and provides the basis for further studies to develop novel strategies for the control of granulocytic anaplasmosis.

Graft polymerization of styryl bisphosphonate monomer onto polypropylene films for inhibition of biofilm formation.

PubMed

Steinmetz, Hanna P; Rudnick-Glick, Safra; Natan, Michal; Banin, Ehud; Margel, Shlomo

2016-11-01

There has been increased concern during the past few decades over the role bacterial biofilms play in causing a variety of health problems, especially since they exhibit a high degree of resistance to antibiotics and are able to survive in hostile environments. Biofilms consist of bacterial aggregates enveloped by a self-produced matrix attached to the surface. Ca(2+) ions promote the formation of biofilms, and enhance their stability, viscosity, and strength. Bisphosphonates exhibit a high affinity for Ca(2+) ions, and may inhibit the formation of biofilms by acting as sequestering agents for Ca(2+) ions. Although the antibacterial activity of bisphosphonates is well known, research into their anti-biofilm behavior is still in its early stages. In this study, we describe the synthesis of a new thin coating composed of poly(styryl bisphosphonate) grafted onto oxidized polypropylene films for anti-biofilm applications. This grafting process was performed by graft polymerization of styryl bisphosphonate vinylic monomer onto O2 plasma-treated polypropylene films. The surface modification of the polypropylene films was confirmed using surface measurements, including X-ray photoelectron spectroscopy, atomic force microscopy, and water contact angle goniometry. Significant inhibition of biofilm formation was achieved for both Gram-negative and Gram-positive bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical reactions in perfume ageing.

PubMed

Blakeway, J M; Frey, M L; Lacroix, S; Salerno, M S

1987-10-01

Summary The interactions between a typical range of perfume materials, alcohol, water, air, elevated temperatures and daylight have been studied. The changes of composition, acidity, peroxide content and the formation of new molecules were followed. The stabilizing effects of UV absorbers, antioxidants and sequestering agents were examined; - the formation of acid reaction products was accelerated by air, temperature, daylight and the presence of natural products; - peroxide formation was accelerated by heat and light and the presence of air; as the acidity increased, the peroxides decomposed; - the acetalization of other aldehydes was accelerated by temperature and daylight and the presence of natural products up to 40% of certain aldehydes may be converted into acetals after 3 months at 37 degrees C; - many stereoisomerizations occur, e.g., transisoeugenol is converted up to 10% into the cis isomer after 3 months at 37 degrees C and 58% in daylight; - evaluation of antioxidants UV absorbers and sequestering agents showed a significant protection against deterioration only by EDTA dipotassium salt; - ethanol was converted into acetaldehyde and its diethylacetal by peroxides present and formed on ageing up to 0.08%. Natural products accelerated this formation; - the reaction between benzoyl peroxide and ethanol was shown to yield up to 63% of acetaldehyde+diethyl acetal whilst di-t-butyl peroxide gave only 23% under the same conditions. These results go some way to explaining odour changes in perfume ageing.

mTORC1 Coordinates Protein Synthesis and Immunoproteasome Formation via PRAS40 to Prevent Accumulation of Protein Stress.

PubMed

Yun, Young Sung; Kim, Kwan Hyun; Tschida, Barbara; Sachs, Zohar; Noble-Orcutt, Klara E; Moriarity, Branden S; Ai, Teng; Ding, Rui; Williams, Jessica; Chen, Liqiang; Largaespada, David; Kim, Do-Hyung

2016-02-18

Reduction of translational fidelity often occurs in cells with high rates of protein synthesis, generating defective ribosomal products. If not removed, such aberrant proteins can be a major source of cellular stress causing human diseases. Here, we demonstrate that mTORC1 promotes the formation of immunoproteasomes for efficient turnover of defective proteins and cell survival. mTORC1 sequesters precursors of immunoproteasome β subunits via PRAS40. When activated, mTORC1 phosphorylates PRAS40 to enhance protein synthesis and simultaneously to facilitate the assembly of the β subunits for forming immunoproteasomes. Consequently, the PRAS40 phosphorylations play crucial roles in clearing aberrant proteins that accumulate due to mTORC1 activation. Mutations of RAS, PTEN, and TSC1, which cause mTORC1 hyperactivation, enhance immunoproteasome formation in cells and tissues. Those mutations increase cellular dependence on immunoproteasomes for stress response and survival. These results define a mechanism by which mTORC1 couples elevated protein synthesis with immunoproteasome biogenesis to protect cells against protein stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Proteinuria Impairs Podocyte Regeneration by Sequestering Retinoic Acid

PubMed Central

Peired, Anna; Angelotti, Maria Lucia; Ronconi, Elisa; la Marca, Giancarlo; Mazzinghi, Benedetta; Sisti, Alessandro; Lombardi, Duccio; Giocaliere, Elisa; Della Bona, Marialuisa; Villanelli, Fabio; Parente, Eliana; Ballerini, Lara; Sagrinati, Costanza; Wanner, Nicola; Huber, Tobias B.; Liapis, Helen; Lazzeri, Elena; Lasagni, Laura

2013-01-01

In CKD, the risk of kidney failure and death depends on the severity of proteinuria, which correlates with the extent of podocyte loss and glomerular scarring. We investigated whether proteinuria contributes directly to progressive glomerulosclerosis through the suppression of podocyte regeneration and found that individual components of proteinuria exert distinct effects on renal progenitor survival and differentiation toward a podocyte lineage. In particular, albumin prevented podocyte differentiation from human renal progenitors in vitro by sequestering retinoic acid, thus impairing retinoic acid response element (RARE)-mediated transcription of podocyte-specific genes. In mice with Adriamycin nephropathy, a model of human FSGS, blocking endogenous retinoic acid synthesis increased proteinuria and exacerbated glomerulosclerosis. This effect was related to a reduction in podocyte number, as validated through genetic podocyte labeling in NPHS2.Cre;mT/mG transgenic mice. In RARE-lacZ transgenic mice, albuminuria reduced retinoic acid bioavailability and impaired RARE activation in renal progenitors, inhibiting their differentiation into podocytes. Treatment with retinoic acid restored RARE activity and induced the expression of podocyte markers in renal progenitors, decreasing proteinuria and increasing podocyte number, as demonstrated in serial biopsy specimens. These results suggest that albumin loss through the damaged filtration barrier impairs podocyte regeneration by sequestering retinoic acid and promotes the generation of FSGS lesions. Our findings may explain why reducing proteinuria delays CKD progression and provide a biologic rationale for the clinical use of pharmacologic modulators to induce regression of glomerular diseases. PMID:23949798

Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

PubMed

Li, Wei; Cochell, Thomas; Manthiram, Arumugam

2013-01-01

Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

2,3-Dihydroxybenzoic acid amides of tetraazaalkanes and tetaaza cycloalkanes

DOEpatents

Weitl, F.L.; Raymond, K.N.

1980-01-01

This disclosure is directed to a compound of the formula given in the patent wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO[sub 3]H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes. No Drawings

Capping agents in nanoparticle synthesis: Surfactant and solvent system

NASA Astrophysics Data System (ADS)

Gulati, Shivani; Sachdeva, M.; Bhasin, K. K.

2018-05-01

The preparation of nanomaterials by organometallic precursors require a capping agent, which primarily acts as stabilizing agent and provide colloidal stability along with preventing agglomeration and stopping uncontrolled growth. Final morphology of nanocrystal largely depends on the type of capping agent which is adsorbed on the surface of nanocrystal. Thus capping agents are the keys to obtain the small-sized nanoparticles and are very frequently used in colloidal synthesis of nanoparticles to avoid its overgrowth.

Development of haemostatic decontaminants for the treatment of wounds contaminated with chemical warfare agents. 2: evaluation of in vitro topical decontamination efficacy using undamaged skin.

PubMed

Dalton, Christopher H; Hall, Charlotte A; Lydon, Helen L; Chipman, J K; Graham, John S; Jenner, John; Chilcott, Robert P

2015-05-01

The risk of penetrating, traumatic injury occurring in a chemically contaminated environment cannot be discounted. Should a traumatic injury be contaminated with a chemical warfare (CW) agent, it is likely that standard haemostatic treatment options would be complicated by the need to decontaminate the wound milieu. Thus, there is a need to develop haemostatic products that can simultaneously arrest haemorrhage and decontaminate CW agents. The purpose of this study was to evaluate a number of candidate haemostats for efficacy as skin decontaminants against three CW agents (soman, VX and sulphur mustard) using an in vitro diffusion cell containing undamaged pig skin. One haemostatic product (WoundStat™) was shown to be as effective as the standard military decontaminants Fuller's earth and M291 for the decontamination of all three CW agents. The most effective haemostatic agents were powder-based and use fluid absorption as a mechanism of action to sequester CW agent (akin to the decontaminant Fuller's earth). The envisaged use of haemostatic decontaminants would be to decontaminate from within wounds and from damaged skin. Therefore, WoundStat™ should be subject to further evaluation using an in vitro model of damaged skin. Copyright © 2014 Crown copyright. Journal of Applied Toxicology © 2014 John Wiley & Sons, Ltd.

Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

NASA Astrophysics Data System (ADS)

Kumar, Nikhil; Upadhyay, Lata Sheo Bachan

2016-11-01

A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month

Induction of systemic resistance in plants by biochar, a soil-applied carbon sequestering agent.

PubMed

Elad, Yigal; David, Dalia Rav; Harel, Yael Meller; Borenshtein, Menahem; Kalifa, Hananel Ben; Silber, Avner; Graber, Ellen R

2010-09-01

Biochar is the solid coproduct of biomass pyrolysis, a technique used for carbon-negative production of second-generation biofuels. The biochar can be applied as a soil amendment, where it permanently sequesters carbon from the atmosphere as well as improves soil tilth, nutrient retention, and crop productivity. In addition to its other benefits in soil, we found that soil-applied biochar induces systemic resistance to the foliar fungal pathogens Botrytis cinerea (gray mold) and Leveillula taurica (powdery mildew) on pepper and tomato and to the broad mite pest (Polyphagotarsonemus latus Banks) on pepper. Levels of 1 to 5% biochar in a soil and a coconut fiber-tuff potting medium were found to be significantly effective at suppressing both diseases in leaves of different ages. In long-term tests (105 days), pepper powdery mildew was significantly less severe in the biochar-treated plants than in the plants from the unamended controls although, during the final 25 days, the rate of disease development in the treatments and controls was similar. Possible biochar-related elicitors of systemic induced resistance are discussed.

Loss of Selenium-Binding Protein 1 Decreases Sensitivity to Clastogens and Intracellular Selenium Content in HeLa Cells.

PubMed

Zhao, Changhui; Zeng, Huawei; Wu, Ryan T Y; Cheng, Wen-Hsing

2016-01-01

Selenium-binding protein 1 (SBP1) is not a selenoprotein but structurally binds selenium. Loss of SBP1 during carcinogenesis usually predicts poor prognosis. Because genome instability is a hallmark of cancer, we hypothesize that SBP1 sequesters cellular selenium and sensitizes cancer cells to DNA-damaging agents. To test this hypothesis, we knocked down SBP1 expression in HeLa cervical cancer cells by employing a short hairpin RNA (shRNA) approach. Reduced sensitivity to hydrogen peroxide, paraquat and camptothecin, reactive oxygen species content, and intracellular retention of selenium after selenomethionine treatment were observed in SBP1 shRNA HeLa cells. Results from Western analyses showed that treatment of HeLa cells with selenomethionine resulted in increased SBP1 protein expression in a dose-dependent manner. Knockdown of SBP1 rendered HeLa cells increased expression of glutathione peroxidase-1 but not glutathione peroxidase-4 protein levels and accelerated migration from a wound. Altogether, SBP1 retains supplemental selenium and sensitizes HeLa cancer cells to clastogens, suggesting a new cancer treatment strategy by sequestering selenium through SBP1.

A redox-based mechanism for nitric oxide-induced inhibition of DNA synthesis in human vascular smooth muscle cells

PubMed Central

Bundy, Ruth E; Marczin, Nándor; Chester, Adrian H; Yacoub, Magdi

2000-01-01

The current study explored potential redox mechanisms of nitric oxide (NO)-induced inhibition of DNA synthesis in cultured human and rat aortic smooth muscle cells.Exposure to S-nitrosothiols, DETA-NONOate and NO itself inhibited ongoing DNA synthesis and S phase progression in a concentration-dependent manner, as measured by thymidine incorporation and flow cytometry. Inhibition by NO donors occurred by release of NO, as detected by chemiluminescence and judged by the effects of NO scavengers, haemoglobin and cPTIO.Co-incubation with redox compounds, N-acetyl-L-cysteine, glutathione and L-ascorbic acid prevented NO inhibition of DNA synthesis. These observations suggest that redox agents may alternatively attenuate NO bioactivity extracellularly, interfere with intracellular actions of NO on the DNA synthesis machinery or restore DNA synthesis after established inhibition by NO.Recovery of DNA synthesis after inhibition by NO was similar with and without redox agents suggesting that augmented restoration of DNA synthesis is an unlikely mechanism to explain redox regulation.Study of extracellular interactions revealed that all redox agents potentiated S-nitrosothiol decomposition and NO release.Examination of intracellular NO bioactivity showed that as opposed to attenuation of NO inhibition of DNA synthesis by redox agents, there was no inhibition (potentiation in the presence of ascorbic acid) of soluble guanylate cyclase (sGC) activation judged by cyclic GMP accumulation in rat cells.These data provide evidence that NO-induced inhibition of ongoing DNA synthesis is sensitive to redox environment. Redox processes might protect the DNA synthesis machinery from inhibition by NO, in the setting of augmented liberation of biologically active NO from NO donors. PMID:10742309

Thrombospondin-1 as a Paradigm for the Development of Antiangiogenic Agents Endowed with Multiple Mechanisms of Action

PubMed Central

Rusnati, Marco; Urbinati, Chiara; Bonifacio, Silvia; Presta, Marco; Taraboletti, Giulia

2010-01-01

Uncontrolled neovascularization occurs in several angiogenesis-dependent diseases, including cancer. Neovascularization is tightly controlled by the balance between angiogenic growth factors and antiangiogenic agents. The various natural angiogenesis inhibitors identified so far affect neovascularization by different mechanisms of action. Thrombospondin-1 (TSP-1) is a matricellular modular glycoprotein that acts as a powerful endogenous inhibitor of angiogenesis. It acts both indirectly, by sequestering angiogenic growth factors and effectors in the extracellular environment, and directly, by inducing an antiangiogenic program in endothelial cells following engagement of specific receptors including CD36, CD47, integrins and proteoglycans (all involved in angiogenesis ). In view of its central, multifaceted role in angiogenesis, TSP-1 has served as a source of antiangiogenic tools, including TSP-1 fragments, synthetic peptides and peptidomimetics, gene therapy strategies, and agents that up-regulate TSP-1 expression. This review discusses TSP-1-based inhibitors of angiogenesis, their mechanisms of action and therapeutic potential, drawing our experience with angiogenic growth factor-interacting TSP-1 peptides, and the possibility of exploiting them to design novel antiangiogenic agents. PMID:27713299

One-step, low-temperature fabrication of CdS quantum dots by watermelon rind: a green approach

PubMed Central

Lakshmipathy, Rajasekhar; Sarada, Nallani Chakravarthula; Chidambaram, K; Pasha, Sk Khadeer

2015-01-01

We investigated the one-step synthesis of CdS nanoparticles via green synthesis that used aqueous extract of watermelon rind as a capping and stabilizing agent. Preliminary phytochemical analysis depicted the presence of carbohydrates which can act as capping and stabilizing agents. Synthesized CdS nanoparticles were characterized using UV-visible, Fourier transform infrared spectroscopy, X-ray diffraction, EDX, dynamic light scattering, transmission electron microscopy, and atomic force microscopy techniques. The CdS nanoparticles were found to be size- and shape-controlled and were stable even after 3 months of synthesis. The results suggest that watermelon rind, an agro-waste, can be used for synthesis of CdS nanoparticles without any addition of stabilizing and capping agents. PMID:26491319

Cellular compartmentalization of secondary metabolism

PubMed Central

Kistler, H. Corby; Broz, Karen

2015-01-01

Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported. PMID:25709603

Insect heat shock proteins during stress and diapause.

PubMed

King, Allison M; MacRae, Thomas H

2015-01-07

Insect heat shock proteins include ATP-independent small heat shock proteins and the larger ATP-dependent proteins, Hsp70, Hsp90, and Hsp60. In concert with cochaperones and accessory proteins, heat shock proteins mediate essential activities such as protein folding, localization, and degradation. Heat shock proteins are synthesized constitutively in insects and induced by stressors such as heat, cold, crowding, and anoxia. Synthesis depends on the physiological state of the insect, but the common function of heat shock proteins, often working in networks, is to maintain cell homeostasis through interaction with substrate proteins. Stress-induced expression of heat shock protein genes occurs in a background of protein synthesis inhibition, but in the course of diapause, a state of dormancy and increased stress tolerance, these genes undergo differential regulation without the general disruption of protein production. During diapause, when ATP concentrations are low, heat shock proteins may sequester rather than fold proteins.

Synthesis and biological activity of mustard derivatives of thymine.

PubMed

Hadj-Bouazza, Amel; Teste, Karine; Colombeau, Ludovic; Chaleix, Vincent; Zerrouki, Rachida; Kraemer, Michel; Sainte Catherine, Odile

2008-05-01

The synthesis and biological activity of a novel DNA cross-linking antitumor agent is presented. The new alkylating agent significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.

Synthesis of Purine Nucleoside and Nucleotide Analogs as Antiparasitic Agents.

DTIC Science & Technology

1979-09-01

was to conduct studies on the synthesis of purine nucleoside and nucleotide analogs as anti- parasitic agents. The primary target compounds were 5...antiparasitic agents. - Jaffe has proposed that the susceptibility of pathogenic helminths and protozoa to fraudulent purine, in contrast to pyrimidine...8217-substituted derivatives are thus designed to inhibit nucleoside and nucleotide kinases as well as other parasitic enzymes. Mammalian cells, onthe

Synthesis, Characterization, and Multimillion-Atom Simulation of Halogen-Based Energetic Materials for Agent Defeat

DTIC Science & Technology

2013-04-01

DTRA-TR-13-23 Synthesis, Characterization, and Multimillion -Atom Simulation of Halogen-Based Energetic Materials for Agent Defeat Approved for...reagents for the destruction of biologically active materials and a simulation of their reactions on a multimillion atom scale with quantum...explosives for destruction of chemical & biological agents. Multimillion -atom molecular dynamics simulations with quantum mechanical accuracy were

Changes in isoprenoid lipid synthesis by gemfibrozil and clofibric acid in rat hepatocytes.

PubMed

Hashimoto, F; Taira, S; Hayashi, H

2000-05-15

We studied whether gemfibrozil and clofibric acid alter isoprenoid lipid synthesis in rat hepatocytes. After incubation of the cells with the agent for 74 hr, [(14)C]acetate or [(3)H]mevalonate was added, and the cells were further incubated for 4 hr. Gemfibrozil and clofibric acid increased ubiquinone synthesis from [(14)C]acetate and [(3)H]mevalonate. The effect of gemfibrozil was greater than that of clofibric acid. Also, gemfibrozil decreased dolichol synthesis from [(14)C]acetate and [(3)H]mevalonate. However, clofibric acid increased dolichol synthesis from [(3)H]mevalonate. Gemfibrozil decreased cholesterol synthesis from [(14)C]acetate and [(3)H]mevalonate. Clofibric acid decreased cholesterol synthesis from [(14)C]acetate, but did not affect synthesis from [(3)H]mevalonate. These results suggest that both agents, at different rates, activate the synthetic pathway of ubiquinone, at least from mevalonate. Gemfibrozil may inhibit the synthetic pathway of dolichol, at least from mevalonate. Contrary to gemfibrozil, clofibric acid may activate the synthetic pathway of dolichol from mevalonate. Gemfibrozil may inhibit the synthetic pathway of cholesterol from mevalonate in addition to the pathway from acetate to mevalonate inhibited by both agents.

Air Activated Self-Decontaminating Polydicyclopentadiene PolyHIPE Foams for Rapid Decontamination of Chemical Warfare Agents.

PubMed

McGann, Christopher L; Daniels, Grant C; Giles, Spencer L; Balow, Robert B; Miranda-Zayas, Jorge L; Lundin, Jeffrey G; Wynne, James H

2018-06-01

The threat of chemical warfare agents (CWA) compels research into novel self-decontaminating materials (SDM) for the continued safety of first-responders, civilians, and active service personnel. The capacity to actively detoxify, as opposed to merely sequester, offending agents under typical environmental conditions defines the added value of SDMs in comparison to traditional adsorptive materials. Porous polymers, synthesized via the high internal phase emulsion (HIPE) templating, provide a facile fabrication method for materials with permeable open cellular structures that may serve in air filtration applications. PolyHIPEs comprising polydicyclopentadiene (polyDCPD) networks form stable hydroperoxide species following activation in air under ambient conditions. The hydroperoxide-containing polyDCPD materials react quickly with CWA simulants, Demeton-S and 2-chloroethyl ethyl sulfide, forming oxidation products as confirmed via gas chromatography mass spectrometry. The simplicity of the detoxification chemistry paired with the porous foam form factor presents an exciting opportunity for the development of self-decontaminating filter media. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fatimah, Soja Siti, E-mail: soja-sf@upi.edu; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor; Bahti, Husein H.

2016-02-08

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, andmore » using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.« less

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

NASA Astrophysics Data System (ADS)

Fatimah, Soja Siti; Bahti, Husein H.; Hastiawan, Iwan; Permanasari, Anna

2016-02-01

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Metal Ion-Catalyzed Alcoholysis as a Strategy for the High Loading Destruction of Chemical Warfare Organophosphorus Agents

DTIC Science & Technology

2013-11-01

products was developed. At the core of the strategy was the use of the thionyl chloride reaction (shown above) for the synthesis of the G agent simulant...The synthesis diverges at the chloridate stage, where instead of conversion to the fluoride derivative, conversion to the mixed ester is accomplished...12 6.2 Synthesis of Product Standards ........................................................................14 6.3

Chemical and Biological Studies of Nakiterpiosin and Nakiterpiosinone

PubMed Central

Gao, Shuanhu; Wang, Qiaoling; Huang, Lily Jun-Shen; Lum, Lawrence; Chen, Chuo

2009-01-01

Nakiterpiosin and nakiterpiosinone are two related C-nor-D-homosteroids isolated from the sponge Terpios hoshinota that show promise as anti-cancer agents. We have previously described the asymmetric synthesis and the revision of the relative configuration of nakiterpiosin. We now provide detailed information on the stereochemical analysis that supports our structure revision and the synthesis of the originally proposed and revised nakiterpiosin. In addition, we herein describe a refined approach for the synthesis of nakiterpiosin, the first synthesis of nakiterpiosinone, and preliminary mechanistic studies of nakiterpiosin's action in mammalian cells. Cells treated with nakiterpiosin exhibit compromised formation of the primary cilium, an organelle that functions as an assembly point for components of the Hedgehog signal transduction pathway. We provide evidence that the biological effects exhibited by nakiterpiosin are mechanistically distinct from those of well-established anti-mitotic agents such as taxol. Nakiterpiosin may be useful as an anti-cancer agent in those tumors resistant to existing anti-mitotic agents and those dependent on Hedgehog pathway responses for growth. PMID:20000429

Minigene-like inhibition of protein synthesis mediated by hungry codons near the start codon

PubMed Central

Jacinto-Loeza, Eva; Vivanco-Domínguez, Serafín; Guarneros, Gabriel; Hernández-Sánchez, Javier

2008-01-01

Rare AGA or AGG codons close to the initiation codon inhibit protein synthesis by a tRNA-sequestering mechanism as toxic minigenes do. To further understand this mechanism, a parallel analysis of protein synthesis and peptidyl-tRNA accumulation was performed using both a set of lacZ constructs where AGAAGA codons were moved codon by codon from +2, +3 up to +7, +8 positions and a series of 3–8 codon minigenes containing AGAAGA codons before the stop codon. β-Galactosidase synthesis from the AGAAGA lacZ constructs (in a Pth defective in vitro system without exogenous tRNA) diminished as the AGAAGA codons were closer to AUG codon. Likewise, β-galactosidase expression from the reporter +7 AGA lacZ gene (plus tRNA, 0.25 μg/μl) waned as the AGAAGAUAA minigene shortened. Pth counteracted both the length-dependent minigene effect on the expression of β-galactosidase from the +7 AGA lacZ reporter gene and the positional effect from the AGAAGA lacZ constructs. The +2, +3 AGAAGA lacZ construct and the shortest +2, +3 AGAAGAUAA minigene accumulated the highest percentage of peptidyl-tRNAArg4. These observations lead us to propose that hungry codons at early positions, albeit with less strength, inhibit protein synthesis by a minigene-like mechanism involving accumulation of peptidyl-tRNA. PMID:18583364

THE PRESENCE OF ENDOGENOUS PYROGEN IN NORMAL RABBIT TISSUES.

PubMed

SNELL, E S; ATKINS, E

1965-06-01

Saline extracts of homogenized, uninfected, rabbit tissues produced febrile responses when injected intravenously into rabbits. Extracts of muscle, lung, and heart evoked fevers that were similar to those induced by leucocyte pyrogen; extracts of spleen, liver, and kidney caused more sustained fevers. The minimal pyrogenic dose appeared to be between 1.5 and 3 gm wet weight of tissue. Evidence is presented that neither Gram-negative bacterial endotoxin nor polymorphonuclear leucocytes (circulating or sequestered in the tissues) can be implicated as the source of pyrogen in tissue extracts. It seems likely, therefore, that a pyrogenic material of truly endogenous origin is widely distributed in tissues. Tissue pyrogen appears to be a large molecule which is relatively resistant to treatment with acid but not with alkali. Possible pathological roles for this endogenous agent (or agents) are briefly indicated.

Strategies for the synthesis of the novel antitumor agent peloruside A

PubMed Central

Williams, David R; Nag, Partha P; Zorn, Nicolas

2009-01-01

The microtubule-stabilizing agent (+)-peloruside A has emerged as a potential therapeutic agent for the treatment of cancer. Two total syntheses have been published and these reports have stimulated additional studies to advance the methodology and strategies for accessing this molecular architecture. This review details the biological data, modeling and conformation analyses, and synthetic studies toward the synthesis of (+)-peloruside A, that were reported prior to December 2007. PMID:18283613

ROOM TEMPERATURE BULK SYNTHESIS OF SILVER NANOCABLES WRAPPED WITH POLYPYRROLE

EPA Science Inventory

Wet chemical synthesis of silver cables wrapped with polypyrrole is reported in aqueous media without use of any surfactant/capping agent and/or template. The method employs direct polymerization of pyrrole of an aqueous solution with AgNO3 as an oxidizing agent. The four probe c...

Synthesis of (+)-Antroquinonol: An Antihyperglycemic Agent.

PubMed

Sulake, Rohidas S; Lin, Hsiao-Han; Hsu, Chia-Yu; Weng, Ching-Feng; Chen, Chinpiao

2015-06-19

The total synthesis of antroquinonol has been accomplished through Suzuki-Miyaura cross-coupling and Barton-McCombie reaction, and the α,β-unsaturation was achieved through selenylation and oxidation protocols. In vitro and in vivo studies on the glucose-lowering properties of antroquinonol indicate that it is a potential antidiabetic agent.

76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... compounds have radical curative antimalarial activity. Brenda S. Bowen, Army Federal Register Liaison... Guanidylimidazoline Derivatives as Antimalarial Agents, Synthesis of and Methods of Use Thereof AGENCY: Department of... ``Guanidylimidazole and Guanidylimidazoline Derivatives as Antimalarial Agents, Synthesis of and Methods of Use...

Preparation of GST Fusion Proteins.

PubMed

Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

2007-04-01

INTRODUCTIONThis protocol describes the preparation of glutathione-S-transferase (GST) fusion proteins, which have had a wide range of applications since their introduction as tools for synthesis of recombinant proteins in bacteria. GST was originally selected as a fusion moiety because of several desirable properties. First and foremost, when expressed in bacteria alone, or as a fusion, GST is not sequestered in inclusion bodies (in contrast to previous fusion protein systems). Second, GST can be affinity-purified without denaturation because it binds to immobilized glutathione, which provides the basis for simple purification. Consequently, GST fusion proteins are routinely used for antibody generation and purification, protein-protein interaction studies, and biochemical analysis.

Intelligent Agents and Their Potential for Future Design and Synthesis Environment

NASA Technical Reports Server (NTRS)

Noor, Ahmed K. (Compiler); Malone, John B. (Compiler)

1999-01-01

This document contains the proceedings of the Workshop on Intelligent Agents and Their Potential for Future Design and Synthesis Environment, held at NASA Langley Research Center, Hampton, VA, September 16-17, 1998. The workshop was jointly sponsored by the University of Virginia's Center for Advanced Computational Technology and NASA. Workshop attendees came from NASA, industry and universities. The objectives of the workshop were to assess the status of intelligent agents technology and to identify the potential of software agents for use in future design and synthesis environment. The presentations covered the current status of agent technology and several applications of intelligent software agents. Certain materials and products are identified in this publication in order to specify adequately the materials and products that were investigated in the research effort. In no case does such identification imply recommendation or endorsement of products by NASA, nor does it imply that the materials and products are the only ones or the best ones available for this purpose. In many cases equivalent materials and products are available and would probably produce equivalent results.

76 FR 38122 - Notice of Availability for Exclusive, Non-Exclusive, or Partially-Exclusive Licensing of an...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... curative antimalarial activity. Brenda S. Bowen, Army Federal Register Liaison Officer. [FR Doc. 2011-16258... Derivatives as Antimalarial Agents, Synthesis of and Methods of Use Thereof AGENCY: Department of the Army, Do...-Imidazoline Derivatives as Antimalarial Agents, Synthesis and Methods of Use Thereof,'' filed on April 26...

Mercury removal in utility wet scrubber using a chelating agent

DOEpatents

Amrhein, Gerald T.

2001-01-01

A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

Facile synthesis and application of a carbon foam with large mesopores.

PubMed

Fu, Liling; Qi, Genggeng; Sahore, Ritu; Sougrat, Rachid; DiSalvo, Francis J; Giannelis, Emmanuel P

2013-11-28

By combining elements of hard- and soft-templating, a facile synthesis method for carbon foams with large mesopores has been demonstrated. A commercial Pluronic surfactant was used as the structure-directing agent as well as the carbon precursor. No micelle swelling agent or post treatment is necessary to enlarge mesopores. As such this method requires fewer synthesis steps and is highly scalable. The as-synthesized meso-carbons showed potential applications in the fields of carbon oxide capture and lithium-sulfur batteries.

DNA excision repair in cell extracts from human cell lines exhibiting hypersensitivity to DNA-damaging agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansson, J.; Keyse, S.M.; Lindahl, T.

Whole cell extracts from human lymphoid cell lines can perform in vitro DNA repair synthesis in plasmids damaged by agents including UV or cis-diamminedichloroplatinum(II) (cis-DDP). Extracts from xeroderma pigmentosum (XP) cells are defective in repair synthesis. We have now studied in vitro DNA repair synthesis using extracts from lymphoblastoid cell lines representing four human hereditary syndromes with increased sensitivity to DNA-damaging agents. Extracts of cell lines from individuals with the sunlight-sensitive disorders dysplastic nevus syndrome or Cockayne's syndrome (complementation groups A and B) showed normal DNA repair synthesis in plasmids with UV photoproducts. This is consistent with in vivo measurementsmore » of the overall DNA repair capacity in such cell lines. A number of extracts were prepared from two cell lines representing the variant form of XP (XP-V). Half of the extracts prepared showed normal levels of in vitro DNA repair synthesis in plasmids containing UV lesions, but the remainder of the extracts from the same cell lines showed deficient repair synthesis, suggesting the possibility of an unusually labile excision repair protein in XP-V. Fanconi's anemia (FA) cells show cellular hypersensitivity to cross-linking agents including cis-DDP. Extracts from cell lines belonging to two different complementation groups of FA showed normal DNA repair synthesis in plasmids containing cis-DDP or UV adducts. Thus, there does not appear to be an overall excision repair defect in FA, but the data do not exclude a defect in the repair of interstrand DNA cross-links.« less

Microbial synthesis of poly(epsilon-lysine) and its various applications.

PubMed

Shih, Ing-Lung; Shen, Ming-Haw; Van, Yi-Tsong

2006-06-01

This review article deals with the microbial synthesis, physiochemical properties, and potential applications of poly-epsilon-lysine (epsilon-PL), which is a naturally occurring biomaterial that is water soluble, biodegradable, edible and non-toxic toward humans and the environment. The potential applications of epsilon-PL as food preservatives, emulsifying agent, dietary agent, biodegradable fibers, highly water absorbable hydrogels, drug carriers, anticancer agent enhancer, biochip coatings in the fields of food, medicine, agriculture and electronics are also discussed in this review.

Synthesis of mutual azo prodrugs of anti-inflammatory agents and peptides facilitated by α-aminoisobutyric acid.

PubMed

Kennedy, David A; Vembu, Nagarajan; Fronczek, Frank R; Devocelle, Marc

2011-12-02

Reported is the synthesis of azo mutual prodrugs of the nonsteroidal anti-inflammatory agents (NSAIDs) 4-aminophenylacetic acid (4-APAA) or 5-aminosalicylic acid (5-ASA) with peptides, including an antibiotic peptide temporin analogue modified at the amino terminal by an α-aminoisobutyric acid (Aib) residue. These prodrugs are designed for colonic delivery of two agents to treat infection and inflammation by the bacterial pathogen Clostridium difficile . © 2011 American Chemical Society

Model-based synthesis of locally contingent responses to global market signals

NASA Astrophysics Data System (ADS)

Magliocca, N. R.

2015-12-01

Rural livelihoods and the land systems on which they depend are increasingly influenced by distant markets through economic globalization. Place-based analyses of land and livelihood system sustainability must then consider both proximate and distant influences on local decision-making. Thus, advancing land change theory in the context of economic globalization calls for a systematic understanding of the general processes as well as local contingencies shaping local responses to global signals. Synthesis of insights from place-based case studies of land and livelihood change is a path forward for developing such systematic knowledge. This paper introduces a model-based synthesis approach to investigating the influence of local socio-environmental and agent-level factors in mediating land-use and livelihood responses to changing global market signals. A generalized agent-based modeling framework is applied to six case-study sites that differ in environmental conditions, market access and influence, and livelihood settings. The largest modeled land conversions and livelihood transitions to market-oriented production occurred in sties with relatively productive agricultural land and/or with limited livelihood options. Experimental shifts in the distributions of agents' risk tolerances generally acted to attenuate or amplify responses to changes in global market signals. Importantly, however, responses of agents at different points in the risk tolerance distribution varied widely, with the wealth gap growing wider between agents with higher or lower risk tolerance. These results demonstrate model-based synthesis is a promising approach to overcome many of the challenges of current synthesis methods in land change science, and to identify generalized as well as locally contingent responses to global market signals.

Regulation of yeast DNA polymerase δ-mediated strand displacement synthesis by 5′-flaps

PubMed Central

Koc, Katrina N.; Stodola, Joseph L.; Burgers, Peter M.; Galletto, Roberto

2015-01-01

The strand displacement activity of DNA polymerase δ is strongly stimulated by its interaction with proliferating cell nuclear antigen (PCNA). However, inactivation of the 3′–5′ exonuclease activity is sufficient to allow the polymerase to carry out strand displacement even in the absence of PCNA. We have examined in vitro the basic biochemical properties that allow Pol δ-exo− to carry out strand displacement synthesis and discovered that it is regulated by the 5′-flaps in the DNA strand to be displaced. Under conditions where Pol δ carries out strand displacement synthesis, the presence of long 5′-flaps or addition in trans of ssDNA suppress this activity. This suggests the presence of a secondary DNA binding site on the enzyme that is responsible for modulation of strand displacement activity. The inhibitory effect of a long 5′-flap can be suppressed by its interaction with single-stranded DNA binding proteins. However, this relief of flap-inhibition does not simply originate from binding of Replication Protein A to the flap and sequestering it. Interaction of Pol δ with PCNA eliminates flap-mediated inhibition of strand displacement synthesis by masking the secondary DNA site on the polymerase. These data suggest that in addition to enhancing the processivity of the polymerase PCNA is an allosteric modulator of other Pol δ activities. PMID:25813050

Effect of reducing agents on low-temperature synthesis of nanostructured LiFePO4

NASA Astrophysics Data System (ADS)

Kulka, Andrzej; Walczak, Katarzyna; Zając, Wojciech; Molenda, Janina

2017-09-01

Simple co-precipitation synthesis procedure yielding nanometric LiFePO4 with enhanced electrochemical properties without any post-synthesis heat treatment is presented. XRD, SEM and TEM analysis of the obtained powders revealed platelet crystallites and well crystalized bulk structure. Effective way of decreasing amount of Fe3+ containing phases by addition of reducing agents (KI, (NH4)2S2O3, glucose and the atmosphere of 5%H2-95%Ar) during low-temperature (107 °C) synthesis is described. The traditional analytical chemistry methods or the Mӧssbauer spectroscopy methods revealed that utilization of selected reducing agents diminished Fe3+ concentration from 25 to 12 at%. The constructed cells with optimized LiFePO4 as a cathode material showed superior electrochemical performances, including high reversible capacity up to 162 mAh/g at C/10 current discharge rate, flat voltage plateau with a value close to 3.45 V vs. Li0/+.

Agroforestry: working trees for sequestering carbon on agricultural lands

Treesearch

M.M. Schoeneberger

2008-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon while leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues facing these lands, such as economic diversification, biodiversity, and water quality....

Agroforestry-working trees for sequestering carbon on ag-lands

Treesearch

Michele M. Schoeneberger

2005-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon whle leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues, such as economic diversification, biodiversity, and water quality, facing these lands....

Phthalocyanine Tetraamine Epoxy-Curing Agents

NASA Technical Reports Server (NTRS)

Fohlen, G. M.; Achar, B. N.; Parker, J. A.

1986-01-01

Tough fire- and chemical-resistant epoxies produced by using metalphthalocyanine tetraamines (MPT's) of copper, cobalt, or nickel as curing agents. Synthesis of MPT's commercially realizable and gives pure compounds with almost 90-percent yield. Synthesis applicable for metals with atomic radii of about 1.35 angstroms, including Cu, Co, Ni, Zn, Fe, Pt, Al, and V. Possible to use metal phthalocyanines to cure epoxy resins in homogeneous reaction.

The SEQUEST Family Tree

NASA Astrophysics Data System (ADS)

Tabb, David L.

2015-11-01

Since its introduction in 1994, SEQUEST has gained many important new capabilities, and a host of successor algorithms have built upon its successes. This Account and Perspective maps the evolution of this important tool and charts the relationships among contributions to the SEQUEST legacy. Many of the changes represented improvements in computing speed by clusters and graphics cards. Mass spectrometry innovations in mass accuracy and activation methods led to shifts in fragment modeling and scoring strategies. These changes, as well as the movement of laboratories and lab members, have led to great diversity among the members of the SEQUEST family.

Graphene oxide significantly inhibits cell growth at sublethal concentrations by causing extracellular iron deficiency.

PubMed

Yu, Qilin; Zhang, Bing; Li, Jianrong; Du, Tingting; Yi, Xiao; Li, Mingchun; Chen, Wei; Alvarez, Pedro J J

Graphene oxide (GO)-based materials are increasingly being used in medical materials and consumer products. However, their sublethal effects on biological systems are poorly understood. Here, we report that GO (at 10 to 160 mg/L) induced significant inhibitory effects on the growth of different unicellular organisms, including eukaryotes (i.e. Saccharomyces cerevisiae, Candida albicans, and Komagataella pastoris) and prokaryotes (Pseudomonas fluorescens). Growth inhibition could not be explained by commonly reported cytotoxicity mechanisms such as plasma membrane damage or oxidative stress. Based on transcriptomic analysis and measurement of extra- and intracellular iron concentrations, we show that the inhibitory effect of GO was mainly attributable to iron deficiency caused by binding to the O-functional groups of GO, which sequestered iron and disrupted iron-related physiological and metabolic processes. This inhibitory mechanism was corroborated with supplementary experiments, where adding bathophenanthroline disulfonate-an iron chelating agent-to the culture medium exerted similar inhibition, whereas removing surface O-functional groups of GO decreased iron sequestration and significantly alleviated the inhibitory effect. These findings highlight a potential indirect detrimental effect of nanomaterials (i.e. scavenging of critical nutrients), and encourage research on potential biomedical applications of GO-based materials to sequester iron and enhance treatment of iron-dependent diseases such as cancer and some pathogenic infections.

Does Diffusion Sequester Heavy Metals in Old Contamination Soils?

NASA Astrophysics Data System (ADS)

Ma, J.; Jennings, A. A.

2002-12-01

Old soil contamination refers to soil contamination that has aged over a long period of time. For example, at some brownfields, the soil heavy metal contamination can be one hundred or more years old. When contamination is young, the heavy metals are bound relatively weakly to the soil. However, the speciation and/or mechanisms of association evolve with aging into much more stable forms. It also appears that the metals migrate deeper into the bulk soil matrix where they are less available to participate in surface-related phenomena. Previous research showed elevated heavy metal extraction result after the soil was pulverized, with all other experiment conditions remaining unchanged. This indicates the presence of sequestered heavy metal contamination within the large soil particles (aggregate). The mechanisms of sequestering are uncertain, but diffusion appears to be a major factor. There are two possible pathways of diffusion that can account for heavy metal sequestering: solid-state diffusion through the bulk aggregate or liquid-phase diffusion through micro-pores within the aggregate structure. The second diffusion mechanism can be coupled with sorption (or other surface-related phenomena) on the pore walls. The remediation of sequestered heavy metals is also impacted by diffusion. Grinding a soil significantly reduces its average particle size. This exposes more of its internal bulk volume to extraction and results in much shorter diffusion pathway for the sequestered heavy metals to be released. Evidence has illustrated that this both improves remediation efficiency and provides a method by which the degree of sequestering can be quantified. This paper will present the results of ongoing research that is developing methods to identify the mechanisms of, quantify the magnitude of and determine the relative importance of (i.e. risk analysis) heavy metals sequestered in old contamination soils.

Arsenic speciation in newberyite (MgHPO(4)·3H(2)O) determined by synchrotron X-ray absorption and electron paramagnetic resonance spectroscopies: implications for the fate of arsenic in green fertilizers.

PubMed

Lin, Jinru; Chen, Ning; Pan, Yuanming

2014-06-17

Newberyite (MgHPO4·3H2O), a biomineral and common constituent in guano deposits, is an important decomposition product of struvite that is an increasingly popular green fertilizer recovered from wastewaters. Two samples of newberyite containing 1099 and 25 ppm As have been obtained at pH = 6.4, by using Na2HAsO4·7H2O and NaAsO2 as the dopant, respectively (i.e., Synthesis 1 and Synthesis 2). Synchrotron arsenic K-edge X-ray absorption spectroscopic data of newberyite from Synthesis 1 show that As(5+) is dominant and has a local environment typical of the arsenate species. Single-crystal electron paramagnetic resonance (EPR) spectra of gamma-ray-irradiated newberyite from Synthesis 1 contain two arsenic-associated oxyradicals: [AsO3](2-) and [AsO2](2-) derived from As(5+) and As(3+), respectively, at the P site. Quantitative analyses of powder EPR spectra allow determinations of the As(5+) and As(3+) contents in newberyite from Synthesis 1 and Synthesis 2. Elevated concentrations of arsenic also occur in natural newberyite transformed from struvite in guano deposits and record the accumulation of this metalloid in the food chain. Therefore, newberyite, which sequesters As during crystallization and retains this metalloid during the transformation from struvite, can attenuate arsenic contamination from green fertilizers in moderately acidic soils. Also, the capacity for accommodating both As(5+) and As(3+) in the crystal lattice coupled with simple chemistry and easy crystallization at ambient conditions makes newberyite an attractive material for remediation of arsenic contamination in aqueous environments.

Intelligent microchip networks: an agent-on-chip synthesis framework for the design of smart and robust sensor networks

NASA Astrophysics Data System (ADS)

Bosse, Stefan

2013-05-01

Sensorial materials consisting of high-density, miniaturized, and embedded sensor networks require new robust and reliable data processing and communication approaches. Structural health monitoring is one major field of application for sensorial materials. Each sensor node provides some kind of sensor, electronics, data processing, and communication with a strong focus on microchip-level implementation to meet the goals of miniaturization and low-power energy environments, a prerequisite for autonomous behaviour and operation. Reliability requires robustness of the entire system in the presence of node, link, data processing, and communication failures. Interaction between nodes is required to manage and distribute information. One common interaction model is the mobile agent. An agent approach provides stronger autonomy than a traditional object or remote-procedure-call based approach. Agents can decide for themselves, which actions are performed, and they are capable of flexible behaviour, reacting on the environment and other agents, providing some degree of robustness. Traditionally multi-agent systems are abstract programming models which are implemented in software and executed on program controlled computer architectures. This approach does not well scale to micro-chip level and requires full equipped computers and communication structures, and the hardware architecture does not consider and reflect the requirements for agent processing and interaction. We propose and demonstrate a novel design paradigm for reliable distributed data processing systems and a synthesis methodology and framework for multi-agent systems implementable entirely on microchip-level with resource and power constrained digital logic supporting Agent-On-Chip architectures (AoC). The agent behaviour and mobility is fully integrated on the micro-chip using pipelined communicating processes implemented with finite-state machines and register-transfer logic. The agent behaviour, interaction (communication), and mobility features are modelled and specified on a machine-independent abstract programming level using a state-based agent behaviour language (APL). With this APL a high-level agent compiler is able to synthesize a hardware model (RTL, VHDL), a software model (C, ML), or a simulation model (XML) suitable to simulate a multi-agent system using the SeSAm simulator framework. Agent communication is provided by a simple tuple-space database implemented on node level providing fault tolerant access of global data. A novel synthesis development kit (SynDK) based on a graph-structured database approach is introduced to support the rapid development of compilers and synthesis tools, used for example for the design and implementation of the APL compiler.

Mice exposed in situ to urban air pollution exhibit pulmonary alterations in gene expression in the lipid droplet synthesis pathways.

PubMed

Rowan-Carroll, Andrea; Halappanavar, Sabina; Williams, Andrew; Somers, Christophers M; Yauk, Carole L

2013-05-01

It is clear that particulate air pollution poses a serious risk to human health; however, the underlying mechanisms are not completely understood. We investigated pulmonary transcriptional responses in mice following in-situ exposure to ambient air in a heavily industrialized urban environment. Mature C57BL/CBA male mice were caged in sheds near two working steel mills and a major highway in Hamilton, Ontario, Canada in the spring/summer of 2004. Control mice were housed in the same environment, but received only high-efficiency particle filtered air (HEPA). Whole lung tissues were collected from mice exposed for 3, 10, or for 10 weeks followed by 6 weeks recovery in the laboratory (16 weeks). DNA microarrays were used to profile changes in pulmonary gene expression. Transcriptional profiling revealed changes in the expression of genes implicated in the lipid droplet synthesis (Plin I, Dgat2, Lpl, S3-12, and Agpat2), and antioxidant defense (Ucp1) pathways in mice breathing unfiltered air. We postulate that exposure to urban air, containing an abundance of particulate matter adsorbed with polycyclic aromatic hydrocarbons, triggers lipid droplet (holding depots for lipids and malformed/excess proteins tagged for degradation) synthesis in the lungs, which may act to sequester particulates. Increased lipid droplet synthesis could lead to endogenous/stressor-induced production of reactive oxygen species and activation of antioxidant mechanisms. Further investigation into the stimulation of lipid droplet synthesis in the lung in response to air pollution and the resulting health implications is warranted. Copyright © 2013 Wiley Periodicals, Inc.

Recognition of extended linear and cyclised polyketide mimics by a type II acyl carrier protein† †Electronic supplementary information (ESI) available: Detailed experimental procedures and characterisation data for all new compounds, additional spectra and structural statistics for derivatised ACP three-dimensional structures. See DOI: 10.1039/c5sc03864b Click here for additional data file.

PubMed Central

Dong, Xu; Bailey, Christopher D.; Williams, Christopher; Crosby, John; Simpson, Thomas J.

2016-01-01

Polyketides are secondary metabolites which display both valuable pharmaceutical and agrochemical properties. Biosynthesis is performed by polyketide synthases (PKSs), and the acyl carrier protein (ACP), a small acidic protein, that transports the growing polyketide chain and is essential for activity. Here we report the synthesis of two aromatic probes and a linear octaketide mimic that have been tethered to actinorhodin ACP. These experiments were aimed at probing the ACP's capacity to sequester a non-polar versus a phenolic aromatic ring (that more closely mimics a polyketide intermediate) as well as investigations with extended polyketide chain surrogates. The binding of these mimics has been assessed using high-resolution solution NMR studies and high-resolution structure determination. These results reveal that surprisingly a PKS ACP is able to bind and sequester a bulky non-polar substrate containing an aromatic ring in a fatty acid type binding mode, but the introduction of even a small degree of polarity favours a markedly different association at a surface site that is distinct from that employed by fatty acid ACPs. PMID:28936328

Design and Synthesis of Self-Assembled Monolayers on Mesoporous Supports (SAMMS): The Importance of Ligand Posture in Functional Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryxell, Glen E.; Mattigod, Shas V.; Lin, Yuehe

2007-07-01

Water, and water quality, are issues of critical importance to the future of humankind. The Earth’s water supplies have been contaminated by a wide variety of industrial, military and natural sources. The need exists for an efficient separation technology to remove heavy metal and radionuclide contamination from water. Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to build high efficiency environmental sorbents. These nanoporous ceramics condense a huge amount of surface area into a very small volume. These mesoporous architectures can be subsequently functionalized through molecular self-assembly. These functional mesoporous materials offer significant capabilities in termsmore » of removal of heavy metals and radionuclides from a variety of liquid media, including groundwater, contaminated oils and contaminated chemical weapons. They are highly efficient sorbents, whose rigid, open pore structure allows for rapid, efficient sorption kinetics. Their interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. This manuscript provides a review of the design, synthesis and performance of the sorbent materials. The role that ligand posture plays in the chemistry of these interfacial ligand fields is discussed.« less

New Paradigm Shift for the Green Synthesis of Antibacterial Silver Nanoparticles Utilizing Plant Extracts

PubMed Central

2014-01-01

This review covers general information regarding the green synthesis of antibacterial silver nanoparticles. Owing to their antibacterial properties, silver nanoparticles are widely used in many areas, especially biomedical applications. In green synthesis practices, the chemical reducing agents are eliminated, and biological entities are utilized to convert silver ions to silver nanoparticles. Among the various biological entities, natural plant extracts have emerged as green reducing agents, providing eco-friendly routes for the preparation of silver nanomaterials. The most obvious merits of green synthesis are the increased biocompatibility of the resulting silver nanoparticles and the ease with which the reaction can be carried out. This review summarizes some of the plant extracts that are used to produce antibacterial silver nanoparticles. Additionally, background information regarding the green synthesis and antibacterial activity of silver nanoparticles is provided. Finally, the toxicological aspects of silver nanoparticles are briefly mentioned. PMID:25343010

Green synthesis of silver nanoparticles via plant extracts: beginning a new era in cancer theranostics.

PubMed

Ovais, Muhammad; Khalil, Ali Talha; Raza, Abida; Khan, Muhammad Adeeb; Ahmad, Irshad; Islam, Nazar Ul; Saravanan, Muthupandian; Ubaid, Muhammad Furqan; Ali, Muhammad; Shinwari, Zabta Khan

2016-12-01

With the development of the latest technologies, scientists are looking to design novel strategies for the treatment and diagnosis of cancer. Advances in medicinal plant research and nanotechnology have attracted many researchers to the green synthesis of metallic nanoparticles due to its several advantages over conventional synthesis (simple, fast, energy efficient, one pot processes, safer, economical and biocompatibility). Medicinally active plants have proven to be the best reservoirs of diverse phytochemicals for the synthesis of biogenic silver nanoparticles (AgNPs). In this review, we discuss mechanistic advances in the synthesis and optimization of AgNPs from plant extracts. Moreover, we have thoroughly discussed the recent developments and milestones achieved in the use of biogenic AgNPs as cancer theranostic agents and their proposed mechanism of action. Anticipating all of the challenges, we hope that biogenic AgNPs may become a potential cancer theranostic agent in the near future.

Identification of Protein-Protein Interactions with Glutathione-S-Transferase (GST) Fusion Proteins.

PubMed

Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

2007-08-01

INTRODUCTIONGlutathione-S-transferase (GST) fusion proteins have had a wide range of applications since their introduction as tools for synthesis of recombinant proteins in bacteria. GST was originally selected as a fusion moiety because of several desirable properties. First and foremost, when expressed in bacteria alone, or as a fusion, GST is not sequestered in inclusion bodies (in contrast to previous fusion protein systems). Second, GST can be affinity-purified without denaturation because it binds to immobilized glutathione, which provides the basis for simple purification. Consequently, GST fusion proteins are routinely used for antibody generation and purification, protein-protein interaction studies, and biochemical analysis. This article describes the use of GST fusion proteins as probes for the identification of protein-protein interactions.

Synthesis of organically templated nanoporous tin (II/IV) phosphate for radionuclide and metal sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellman, Dawn M.; Mattigod, Shas V.; Parker, Kent E.

2006-03-20

Nanoporous tin (II/IV) phosphate materials, with spherical morphology, have been synthesized using cetyltrimethylammonium chloride (CH3(CH2)15N(CH3)3Cl) as the surfactant. The structure of the material is stable at 500°C; however, partial oxidation of the material occurs with redox conversion of Sn2+ to Sn4+, resulting in a mixed Sn(II)/ Sn(IV) material. Preliminary batch contact studies were conducted to assess the effectiveness of nanoporous tin phosphate, NP-SnPO, in sequestering redox sensitive metals and radionuclides, technetium(VII), neptunium(V), thorium(IV), and a toxic metal, chromium(VI), from aqueous matrices. Results indicate tin (II) phosphate removed > 95% of all contaminants investigated from solution.

Aerosol reduction/expansion synthesis (A-RES) for zero valent metal particles

DOEpatents

Leseman, Zayd; Luhrs, Claudia; Phillips, Jonathan; Soliman, Haytham

2016-04-12

Various embodiments provide methods of forming zero valent metal particles using an aerosol-reductive/expansion synthesis (A-RES) process. In one embodiment, an aerosol stream including metal precursor compound(s) and chemical agent(s) that produces reducing gases upon thermal decomposition can be introduced into a heated inert atmosphere of a RES reactor to form zero valent metal particles corresponding to metals used for the metal precursor compound(s).

Synthesis of surface bound silver nanoparticles on cellulose fibers using lignin as multi-functional agent.

PubMed

Hu, Sixiao; Hsieh, You-Lo

2015-10-20

Lignin has proven to be highly effective "green" multi-functional binding, complexing and reducing agents for silver cations as well as capping agents for the synthesis of silver nanoparticles on ultra-fine cellulose fibrous membranes. Silver nanoparticles could be synthesized in 10min to be densely distributed and stably bound on the cellulose fiber surfaces at up to 2.9% in mass. Silver nanoparticle increased in sizes from 5 to 100nm and became more polydispersed in size distribution on larger fibers and with longer synthesis time. These cellulose fiber bound silver nanoparticles did not agglomerate under elevated temperatures and showed improved thermal stability. The presence of alkali lignin conferred moderate UV absorbing ability in both UV-B and UV-C regions whereas the bound silver nanoparticles exhibited excellent antibacterial activities toward Escherichia coli. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis and biological activity of imidazopyridine anticoccidial agents: Part II.

PubMed

Scribner, Andrew; Dennis, Richard; Lee, Shuliang; Ouvry, Gilles; Perrey, David; Fisher, Michael; Wyvratt, Matthew; Leavitt, Penny; Liberator, Paul; Gurnett, Anne; Brown, Chris; Mathew, John; Thompson, Donald; Schmatz, Dennis; Biftu, Tesfaye

2008-06-01

Coccidiosis is the major cause of morbidity and mortality in the poultry industry. Protozoan parasites of the genus Eimeria invade the intestinal lining of the avian host causing tissue pathology, poor weight gain, and in some cases mortality. Resistance to current anticoccidials has prompted the search for new therapeutic agents with potent in vitro and in vivo activity against Eimeria. Recently, we reported the synthesis and biological activity of potent imidazo[1,2-a]pyridine anticoccidial agents. Antiparasitic activity is due to inhibition of a parasite specific cGMP-dependent protein kinase (PKG). In this study, we report the synthesis and anticoccidial activity of a second set of such compounds, focusing on derivatization of the amine side chain at the imidazopyridine 7-position. From this series, several compounds showed subnanomolar in vitro activity and commercial levels of in vivo activity. However, the potential genotoxicity of these compounds precludes them from further development.

Facile and one-pot solution synthesis of several kinds of 3D hierarchical flower-like α-Bi2O3 microspheres

NASA Astrophysics Data System (ADS)

Wang, Yajun; Li, Zexue; Yu, Haiyang; Feng, Changgen

2016-09-01

Several kinds of three-dimensional (3D) hierarchical constructed flower-like α-Bi2O3 microspheres were prepared successfully via a simple solution precipitation synthesis at 95∘C and ambient atmospheric pressure in 1h. The synthesis process was operated in ethanol-water system as solvent with the assistance of glycerin and oleic acid as capping agents. These flower-like α-Bi2O3 architectures with diameter of several micrometers were 3D self-assembled from nanorods or nanocubes step by step. By adjusting the concentration of the capping agents, various flower-like α-Bi2O3 microspheres were obtained. The formation of the flower-like superstructures was attributed to the modification of nucleation and growth kinetics, and the guidance of self-assembly approach by capping agents. The formation mechanism of these microstructures was discussed briefly.

Sphingosine 1-phosphate receptor modulators in multiple sclerosis.

PubMed

Subei, Adnan M; Cohen, Jeffrey A

2015-07-01

Sphingosine 1-phosphate (S1P) receptor modulators possess a unique mechanism of action as disease-modifying therapy for multiple sclerosis (MS). Subtype 1 S1P receptors are expressed on the surfaces of lymphocytes and are important in regulating egression from lymph nodes. The S1P receptor modulators indirectly antagonize the receptor's function and sequester lymphocytes in lymph nodes. Fingolimod was the first S1P agent approved in the USA in 2010 for relapsing MS after two phase III trials (FREEDOMS and TRANSFORMS) demonstrated potent efficacy, and good safety and tolerability. Post-marketing experience, as well as a third phase III trial (FREEDOMS II), also showed favorable results. More selective S1P receptor agents-ponesimod (ACT128800), siponimod (BAF312), ozanimod (RPC1063), ceralifimod (ONO-4641), GSK2018682, and MT-1303-are still in relatively early stages of development, but phase I and II trials showed promising efficacy and safety. However, these observations have yet to be reproduced in phase III clinical trials.

Sphingosine 1-Phosphate Receptor Modulators in Multiple Sclerosis

PubMed Central

Subei, Adnan M.

2015-01-01

Sphingosine 1-phosphate (S1P) receptor modulators possess a unique mechanism of action as disease modifying therapy for multiple sclerosis (MS). Subtype 1 S1P receptors are expressed on the surfaces of lymphocytes and are important in regulating egression from lymph nodes. The S1P receptor modulators indirectly antagonize the receptor’s function and sequester lymphocytes in lymph nodes. Fingolimod was the first S1P agent approved in the United States in 2010 for relapsing MS after two phase 3 trials (FREEDOMS and TRANSFORMS) demonstrated potent efficacy, and good safety and tolerability. Post-marketing experience as well as a third phase 3 trial (FREEDOMS II) also showed favorable results. More selective S1P receptor agents: ponesimod (ACT128800), siponimod (BAF312), ozanimod (RPC1063), ceralifimod (ONO-4641), GSK2018682, and MT-1303 are still in relatively early stages of development, but phase 1 and 2 trials showed promising efficacy and safety. However, these observations have yet to be reproduced in phase 3 clinical trials. PMID:26239599

Review lipopeptides biosurfactants: Mean classes and new insights for industrial, biomedical, and environmental applications.

PubMed

Mnif, Inès; Ghribi, Dhouha

2015-05-01

Lipopeptides are microbial surface active compounds produced by a wide variety of bacteria, fungi, and yeast. They are characterized by high structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface, respectively. Surfactin, iturin, and fengycin of Bacillus subtilis are among the most popular lipopeptides. Lipopepetides can be applied in diverse domains as food and cosmetic industries for their emulsification/de-emulsification capacity, dispersing, foaming, moisturizing, and dispersing properties. Also, they are qualified as viscosity reducers, hydrocarbon solubilizing and mobilizing agents, and metal sequestering candidates for application in environment and bioremediation. Moreover, their ability to form pores and destabilize biological membrane permits their use as antimicrobial, hemolytic, antiviral, antitumor, and insecticide agents. Furthermore, lipopeptides can act at the surface and can modulate enzymes activity permitting the enhancement of the activity of certain enzymes ameliorating microbial process or the inhibition of certain other enzymes permitting their use as antifungal agents. This article will present a detailed classification of lipopeptides biosurfactant along with their producing strain and biological activities and will discuss their functional properties and related applications. © 2015 Wiley Periodicals, Inc.

Diastereoselective Synthesis of a Strawberry Flavoring Agent by Epoxidation of Ethyl trans-b-Methylcinnamate

NASA Astrophysics Data System (ADS)

Pageau, Gayle J.; Mabaera, Rodwell; Kosuda, Kathryn M.; Sebelius, Tamara A.; Ghaffari, Ali H.; Kearns, Kenneth A.; McIntyre, Jean P.; Beachy, Tina M.; Thamattoor, Dasan M.

2002-01-01

The diastereoselective synthesis of ethyl (E)-3-methyl-3-phenylglycidate, a strawberry flavoring agent, is carried out by epoxidizing ethyl trans-b-methylcinnamate with m-chloroperbenzoic acid. This epoxidation is appropriate for the introductory organic laboratory and augments the small number of such experiments currently available for undergraduate education. In the course of performing this exercise, students are exposed to many important facets of organic chemistry such as synthesis, reaction mechanism, stereochemistry, chromatography, quantitative analysis, spectroscopy, and computational chemistry. The 1H NMR spectrum of this compound is especially interesting and presents instructive examples of diastereotopic protons and shielding effects of the aromatic ring current.

Treatment and Reuse of Wastewaters Discharged by Petroleum Industries (HMD/Algeria)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sellami, MH, E-mail: sellami2000dz@gmail.com; Loudiyi, K; Boubaker, MC

Industrial wastewaters discharged by petroleum industries contains: oil, heavy metals and chemicals used in the process of oil separation and treatment. These waters are a source of soil, water and air pollution, and lead a mortal danger to the ecosystem. Our aim in this work has an aspect that can contribute to the collective effort to address the enormous amount of water purges storage bins and reuse them to avoid any environmental damage. This was achieved by chemical treating of these wastewaters discharged from three different locations of Hassi Messaoud (HMD) petroleum field by flocculation with (C-5563) followed by coagulationmore » with (C-2061) using two different acids as sequestering namely: Ascorbic and Citric acid. After experiments, the results showed that the wastewater can be treated without sequestering by adding 40 ppm of activated silicates. The best result was obtained by addition of 160 ppm of Ascorbic acid as sequestering agent and 20 ppm of activated silicates; resulting in removal of 92.81 % of suspended matter and 95.53 % of turbidity. Finally we concluded that this wastewater was satisfactorily treated and we recommend either inject it for enhanced oil recovery in industrial closest field (North field) to maintain the reservoir pressure and the improved rate recovery of oil reserves or reuse it in garden irrigation. In order to see the impact of the treated water on plants, irrigation tests have conducted on two types of plants (date palm and shaft apocalyptic) for one year. The tests showed that the thick layer of 5 cm and 0.08mm of particles diameter of dune sand removes most of remaining oil. The sand layer that fills the basin surrounding the shaft is removed and replaced every 06 months. So, Dune sand plays the role of natural filter. The garden plants appear and grow normally.« less

The synthesis of glutamic acid in the absence of enzymes: Implications for biogenesis

NASA Technical Reports Server (NTRS)

Morowitz, Harold; Peterson, Eta; Chang, Sherwood

1995-01-01

This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.

Cytotoxicity and Antineoplastic Activities of Alkylamines and Their Borane Derivatives

PubMed Central

Tse, Elaine Y.; Muhammad, Rosallah A.

1996-01-01

The alkylamines and their related boron derivatives demonstrated potent cytotoxicity against the growth of murine and human tissue cultured cells. These agents did not necessarily require the boron atom to possess potent cytotoxic action in certain tumor lines. Their ability to suppress tumor cell growth was based on their inhibition of DNA and protein syntheses. DNA synthesis was reduced because purine synthesis was blocked at the enzyme site of IMP dehydrogenase by the agents. In addition ribonucleotide reductase and nucleoside kinase activities were reduced by the agents which would account for the reduced d[NTP] pools. The DNA template or molecule may be a target of the drugs with regard to binding of the drug to nucleoside bases or intercalaction of the drug between DNA base pairs. Only some Of the agents caused DNA fragmentation with reduced DNA viscosity. These effects would contribute to overall cell death afforded by the agents. PMID:18472803

Synthesis and Preclinical Characterization of a Cationic Iodinated Imaging Contrast Agent (CA4+) and Its Use for Quantitative Computed Tomography of Ex Vivo Human Hip Cartilage.

PubMed

Stewart, Rachel C; Patwa, Amit N; Lusic, Hrvoje; Freedman, Jonathan D; Wathier, Michel; Snyder, Brian D; Guermazi, Ali; Grinstaff, Mark W

2017-07-13

Contrast agents that go beyond qualitative visualization and enable quantitative assessments of functional tissue performance represent the next generation of clinically useful imaging tools. An optimized and efficient large-scale synthesis of a cationic iodinated contrast agent (CA4+) is described for imaging articular cartilage. Contrast-enhanced CT (CECT) using CA4+ reveals significantly greater agent uptake of CA4+ in articular cartilage compared to that of similar anionic or nonionic agents, and CA4+ uptake follows Donnan equilibrium theory. The CA4+ CECT attenuation obtained from imaging ex vivo human hip cartilage correlates with the glycosaminoglycan content, equilibrium modulus, and coefficient of friction, which are key indicators of cartilage functional performance and osteoarthritis stage. Finally, preliminary toxicity studies in a rat model show no adverse events, and a pharmacokinetics study documents a peak plasma concentration 30 min after dosing, with the agent no longer present in vivo at 96 h via excretion in the urine.

Hydroxypyridonate chelating agents and synthesis thereof

DOEpatents

Raymond, K.N.; Scarrow, R.C.; White, D.L.

1985-11-12

Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided. 4 tabs.

[Synthesis of 1-substituted nitroimidazoles and its evaluation as radiosensitizing agents].

PubMed

Adams, D R; Martul, R; Alvarez, M V; López Zumel, M C; Espada, M

1991-01-01

The synthesis of various substituted nitroimidazoles with lipophilic and hydrophilic side chains as potential radiosensitizing agents is described. The starting material employed was 4(5)-nitroimidazole, which was alkylated via the sodium salt with various chloro-methylated, substituted alcohols and esters, in order to obtain analogues of misonidazole, metronidazole and desmethylmisonidazole of known radiosensitizing and bactericidal activity. Some final products were assayed for their radiosensitizing properties giving negative results under the testing conditions used.

A Simple Secondary Amine Synthesis: Reductive Amination Using Sodium Triacetoxyborohydride

NASA Astrophysics Data System (ADS)

Carlson, Merle W.; Ciszewski, James T.; Bhatti, Micah M.; Swanson, Wesley F.; Wilson, Anne M.

2000-02-01

We present a reductive amination experiment for a second-semester organic chemistry class. It utilizes an imine intermediate and sodium triacetoxyborohydride, a mild reducing agent. The progress of the reaction is followed by TLC as the starting materials (the aldehyde and primary amine), the imine intermediate, and the secondary amine product are visible under ultraviolet light. This experiment provides an introduction to the observation of intermediates, the synthesis of amines, and the concept of mild reducing agents.

Combination of Pim kinase inhibitor SGI-1776 and bendamustine in B-cell lymphoma.

PubMed

Yang, Qingshan; Chen, Lisa S; Neelapu, Sattva S; Gandhi, Varsha

2013-09-01

SGI-1776 is a small-molecule Pim kinase inhibitor that primarily targets c-MYC-driven transcription and cap-dependent translation in mantle cell lymphoma (MCL) cells. Bendamustine is an alkylating chemotherapeutic agent approved for use in B-cell lymphoma that is known to induce DNA damage and initiate response to repair. Our studies were conducted in MCL cell lines JeKo-1 and Mino, as well as primary B-cell lymphoma samples of MCL and splenic marginal zone lymphoma (SMZL), where we treated cells with SGI-1776 and bendamustine. We measured levels of cellular apoptosis, macromolecule synthesis inhibition, and DNA damage induced by drug treatments. Both SGI-1776 and bendamustine effectively induced apoptosis as single agents, and when used in combination, an additive effect in cell killing was observed in MCL cell lines JeKo-1 and Mino, as well as in MCL and SMZL primary cells. As expected, SGI-1776 was effective in inducing a decrease of global RNA and protein synthesis, and bendamustine significantly inhibited DNA synthesis and generated a DNA damage response. When used in combination, the effects were intensified in DNA, RNA, and protein synthesis inhibition compared with single-agent treatments. These data provide a foundation and suggest the feasibility of using Pim kinase inhibitors in combination with chemotherapeutic agents such as bendamustine in B-cell lymphoma. Copyright © 2013 Elsevier Inc. All rights reserved.

Growth mechanisms of MgO nanocrystals via a sol-gel synthesis using different complexing agents

PubMed Central

2014-01-01

In the preparation of nanostructured materials, it is important to optimize synthesis parameters in order to obtain the desired material. This work investigates the role of complexing agents, oxalic acid and tartaric acid, in the production of MgO nanocrystals. Results from simultaneous thermogravimetric analysis (STA) show that the two different synthesis routes yield precursors with different thermal profiles. It is found that the thermal profiles of the precursors can reveal the effects of crystal growth during thermal annealing. X-ray diffraction confirms that the final products are pure, single phase and of cubic shape. It is also found that complexing agents can affect the rate of crystal growth. The structures of the oxalic acid and tartaric acid as well as the complexation sites play very important roles in the formation of the nanocrystals. The complexing agents influence the rate of growth which affects the final crystallite size of the materials. Surprisingly, it is also found that oxalic acid and tartaric acid act as surfactants inhibiting crystal growth even at a high temperature of 950°C and a long annealing time of 36 h. The crystallite formation routes are proposed to be via linear and branched polymer networks due to the different structures of the complexing agents. PMID:24650322

The first total synthesis of sporiolide A.

PubMed

Du, Yuguo; Chen, Qi; Linhardt, Robert J

2006-10-27

The first total synthesis of the natural cytotoxic agent sporiolide A has been accomplished from D-glucal in 16 steps with 6.1% overall yield. Carbohydrates were applied as the chiral templates to manipulate the absolute configuration during the synthesis. Pyridinium chlorochromate (PCC)-promoted transformation of the cyclic enol-ether to lactone, followed by Yamaguchi esterification and intramolecular ring closure metathesis, greatly facilitates synthesis of the target compound.

Synthesis and characterization of a smart contrast agent sensitive to calcium.

PubMed

Dhingra, Kirti; Maier, Martin E; Beyerlein, Michael; Angelovski, Goran; Logothetis, Nikos K

2008-08-07

A novel first-generation Ca2+ sensitive contrast agent, Gd-DOPTRA has been synthesized and characterized. The agent shows approximately 100% relaxivity enhancement upon addition of Ca2+. The agent is selective and sensitive to Ca2+ also in the presence of Mg2+ and Zn2+. The relaxivity studies carried out in physiological fluids prove the prospects of the agent for in vivo measurements.

Enantioselective Total Synthesis of Antibiotic CJ-16,264, Synthesis and Biological Evaluation of Designed Analogues, and Discovery of Highly Potent and Simpler Antibacterial Agents.

PubMed

Nicolaou, K C; Pulukuri, Kiran Kumar; Rigol, Stephan; Buchman, Marek; Shah, Akshay A; Cen, Nicholas; McCurry, Megan D; Beabout, Kathryn; Shamoo, Yousif

2017-11-08

An improved and enantioselective total synthesis of antibiotic CJ-16,264 through a practical kinetic resolution and an iodolactonization reaction to form the iodo pyrrolizidinone fragment of the molecule is described. A series of racemic and enantiopure analogues of CJ-16,264 was designed and synthesized through the developed synthetic technologies and tested against drug-resistant bacterial strains. These studies led to interesting structure-activity relationships and the identification of a number of simpler, and yet equipotent, or even more potent, antibacterial agents than the natural product, thereby setting the foundation for further investigations in the quest for new anti-infective drugs.

Cytotoxic T lymphocyte-dependent tumor growth inhibition by a vascular endothelial growth factor-superantigen conjugate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Qingwen; State Key Laboratory of Genetic Engineering, Fudan University, Shanghai 200433; Jiang, Songmin

2012-11-02

Highlights: Black-Right-Pointing-Pointer We construct and purify a fusion protein VEGF-SEA. Black-Right-Pointing-Pointer VEGF-SEA strongly repressed the growth of murine solid sarcoma 180 (S180) tumors. Black-Right-Pointing-Pointer T cells driven by VEGF-SEA were accumulated around tumor cells bearing VEGFR by mice image model. Black-Right-Pointing-Pointer VEGF-SEA can serve as a tumor targeting agent and sequester CTLs into the tumor site. Black-Right-Pointing-Pointer The induced CTLs could release the cytokines, perforins and granzyme B to kill the tumor cells. -- Abstract: T cells are major lymphocytes in the blood and passengers across the tumor vasculature. If these T cells are retained in the tumor site, amore » therapeutic potential will be gained by turning them into tumor-reactive cytotoxic T lymphocytes (CTLs). A fusion protein composed of human vascular endothelial growth factor (VEGF) and staphylococcal enterotoxin A (SEA) with a D227A mutation strongly repressed the growth of murine solid sarcoma 180 (S180) tumors (control versus VEGF-SEA treated with 15 {mu}g, mean tumor weight: 1.128 g versus 0.252 g, difference = 0.876 g). CD4{sup +} and CD8{sup +} T cells driven by VEGF-SEA were accumulated around VEGFR expressing tumor cells and the induced CTLs could release the tumoricidal cytokines, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Meanwhile, intratumoral CTLs secreted cytolytic pore-forming perforin and granzyme B proteins around tumor cells, leading to the death of tumor cells. The labeled fusion proteins were gradually targeted to the tumor site in an imaging mice model. These results show that VEGF-SEA can serve as a tumor targeting agent and sequester active infiltrating CTLs into the tumor site to kill tumor cells, and could therefore be a potential therapeutical drug for a variety of cancers.« less

Human calprotectin affects the redox speciation of iron.

PubMed

Nakashige, Toshiki G; Nolan, Elizabeth M

2017-08-16

We report that the metal-sequestering human host-defense protein calprotectin (CP, S100A8/S100A9 oligomer) affects the redox speciation of iron (Fe) in bacterial growth media and buffered aqueous solution. Under aerobic conditions and in the absence of an exogenous reducing agent, CP-Ser (S100A8(C42S)/S100A9(C3S) oligomer) depletes Fe from three different bacterial growth media preparations over a 48 h timeframe (T = 30 °C). The presence of the reducing agent β-mercaptoethanol accelerates this process and allows CP-Ser to deplete Fe over a ≈1 h timeframe. Fe-depletion assays performed with metal-binding-site variants of CP-Ser show that the hexahistidine (His 6 ) site, which coordinates Fe(ii) with high affinity, is required for Fe depletion. An analysis of Fe redox speciation in buffer containing Fe(iii) citrate performed under aerobic conditions demonstrates that CP-Ser causes a time-dependent increase in the [Fe(ii)]/[Fe(iii)] ratio. Taken together, these results indicate that the hexahistidine site of CP stabilizes Fe(ii) and thereby shifts the redox equilibrium of Fe to the reduced ferrous state under aerobic conditions. We also report that the presence of bacterial metabolites affects the Fe-depleting activity of CP-Ser. Supplementation of bacterial growth media with an Fe(iii)-scavenging siderophore (enterobactin, staphyloferrin B, or desferrioxamine B) attenuates the Fe-depleting activity of CP-Ser. This result indicates that formation of Fe(iii)-siderophore complexes blocks CP-mediated reduction of Fe(iii) and hence the ability of CP to coordinate Fe(ii). In contrast, the presence of pyocyanin (PYO), a redox-cycling phenazine produced by Pseudomonas aeruginosa that reduces Fe(iii) to Fe(ii), accelerates Fe depletion by CP-Ser under aerobic conditions. These findings indicate that the presence of microbial metabolites that contribute to metal homeostasis at the host/pathogen interface can affect the metal-sequestering function of CP.

Transient neutropenia: Neutrophil distribution and replacement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thakur, M.L.; Li, Jinghua; Binoy, Li

Radiolabeled polymorphonuclear (PMN) receptor-specific proteins or peptides lead the list of agents being evaluated for imaging inflammatory foci. Some of these agents induce transient neutropenia. This study was designed to quantify the degree of dose dependency of neutropenia, determine the duration of neutropenia, identify the organs in which these PMNs sequester and ascertain if these PMNs return to the circulation. Rodent anti-PMN (Gr-1) MAb RB6-8C5 (lgG-2A) and Balb/c mice served as the model, and PMN nonspecific ME 31.3 (lgG-2A) as a control. Circulating PMN number was determined several times, 30 min prior to and between 1 min and 120 hrmore » after MAb administration. Iodine-125-MAbs provided quantification of circulating activity and tissue distribution as a function of time. Data showed the severity of neutropenia increased with the amount of MAb administered (>95% PMNs lost after 150 {mu}g versus <85% after 10 {mu}g). Moreover, the recovery time for PMN counts to reach the pretreatment level also increased in a dose-dependent manner (96 hr at 150 {mu}g versus 4 hr at 10 {mu}g and 2 hr at 2 {mu}g). The blood activity, however, which declined quickly with the neutropenia, never rose again with PMN recovery. As a function of time, radioactivity in the study group decreased from all organs except from the liver and spleen, whereas in the control group; and spleen, 15.5% decrease versus 63.6% decrease in control group. The degree and duration of neutropenia is dose-dependent. PMNs, lost from the circulation, sequester in the reticuloendothelial system, and do not return to circulation. Therefore, they are not available to image inflammatory foci. The PMN concentration is restored to a pretreatment level in a dose-dependent fashion, presumably by freshly released PMNs from bone marrow. 32 refs., 5 figs.« less

Molecular pharmacodynamics of emixustat in protection against retinal degeneration

PubMed Central

Zhang, Jianye; Kiser, Philip D.; Badiee, Mohsen; Palczewska, Grazyna; Dong, Zhiqian; Golczak, Marcin; Tochtrop, Gregory P.; Palczewski, Krzysztof

2015-01-01

Emixustat is a visual cycle modulator that has entered clinical trials as a treatment for age-related macular degeneration (AMD). This molecule has been proposed to inhibit the visual cycle isomerase RPE65, thereby slowing regeneration of 11-cis-retinal and reducing production of retinaldehyde condensation byproducts that may be involved in AMD pathology. Previously, we reported that all-trans-retinal (atRAL) is directly cytotoxic and that certain primary amine compounds that transiently sequester atRAL via Schiff base formation ameliorate retinal degeneration. Here, we have shown that emixustat stereoselectively inhibits RPE65 by direct active site binding. However, we detected the presence of emixustat-atRAL Schiff base conjugates, indicating that emixustat also acts as a retinal scavenger, which may contribute to its therapeutic effects. Using agents that lack either RPE65 inhibitory activity or the capacity to sequester atRAL, we assessed the relative importance of these 2 modes of action in protection against retinal phototoxicity in mice. The atRAL sequestrant QEA-B-001-NH2 conferred protection against phototoxicity without inhibiting RPE65, whereas an emixustat derivative incapable of atRAL sequestration was minimally protective, despite direct inhibition of RPE65. These data indicate that atRAL sequestration is an essential mechanism underlying the protective effects of emixustat and related compounds against retinal phototoxicity. Moreover, atRAL sequestration should be considered in the design of next-generation visual cycle modulators. PMID:26075817

Biological functions of histidine-dipeptides and metabolic syndrome.

PubMed

Song, Byeng Chun; Joo, Nam-Seok; Aldini, Giancarlo; Yeum, Kyung-Jin

2014-02-01

The rapid increase in the prevalence of metabolic syndrome, which is associated with a state of elevated systemic oxidative stress and inflammation, is expected to cause future increases in the prevalence of diabetes and cardiovascular diseases. Oxidation of polyunsaturated fatty acids and sugars produces reactive carbonyl species, which, due to their electrophilic nature, react with the nucleophilic sites of certain amino acids. This leads to formation of protein adducts such as advanced glycoxidation/lipoxidation end products (AGEs/ALEs), resulting in cellular dysfunction. Therefore, an effective reactive carbonyl species and AGEs/ALEs sequestering agent may be able to prevent such cellular dysfunction. There is accumulating evidence that histidine containing dipeptides such as carnosine (β-alanyl-L-histidine) and anserine (β-alanyl-methyl-L-histidine) detoxify cytotoxic reactive carbonyls by forming unreactive adducts and are able to reverse glycated protein. In this review, 1) reaction mechanism of oxidative stress and certain chronic diseases, 2) interrelation between oxidative stress and inflammation, 3) effective reactive carbonyl species and AGEs/ALEs sequestering actions of histidine-dipeptides and their metabolism, 4) effects of carnosinase encoding gene on the effectiveness of histidine-dipeptides, and 5) protective effects of histidine-dipeptides against progression of metabolic syndrome are discussed. Overall, this review highlights the potential beneficial effects of histidine-dipeptides against metabolic syndrome. Randomized controlled human studies may provide essential information regarding whether histidine-dipeptides attenuate metabolic syndrome in humans.

Hepatic entrapment of esterified cholesterol drives continual expansion of whole body sterol pool in lysosomal acid lipase-deficient mice

PubMed Central

Aqul, Amal; Lopez, Adam M.; Posey, Kenneth S.; Taylor, Anna M.; Repa, Joyce J.; Burns, Dennis K.

2014-01-01

Cholesteryl ester storage disease (CESD) results from loss-of-function mutations in LIPA, the gene that encodes lysosomal acid lipase (LAL). Hepatomegaly and deposition of esterified cholesterol (EC) in multiple organs ensue. The present studies quantitated rates of synthesis, absorption, and disposition of cholesterol, and whole body cholesterol pool size in a mouse model of CESD. In 50-day-old lal−/− and matching lal+/+ mice fed a low-cholesterol diet, whole animal cholesterol content equalled 210 and 50 mg, respectively, indicating that since birth the lal−/− mice sequestered cholesterol at an average rate of 3.2 mg·day−1·animal−1. The proportion of the body sterol pool contained in the liver of the lal−/− mice was 64 vs. 6.3% in their lal+/+ controls. EC concentrations in the liver, spleen, small intestine, and lungs of the lal−/− mice were elevated 100-, 35-, 15-, and 6-fold, respectively. In the lal−/− mice, whole liver cholesterol synthesis increased 10.2-fold, resulting in a 3.2-fold greater rate of whole animal sterol synthesis compared with their lal+/+ controls. The rate of cholesterol synthesis in the lal−/− mice exceeded that in the lal+/+ controls by 3.7 mg·day−1·animal−1. Fractional cholesterol absorption and fecal bile acid excretion were unchanged in the lal−/− mice, but their rate of neutral sterol excretion was 59% higher than in their lal+/+ controls. Thus, in this model, the continual expansion of the body sterol pool is driven by the synthesis of excess cholesterol, primarily in the liver. Despite the severity of their disease, the median life span of the lal−/− mice was 355 days. PMID:25147230

Synthesis of 1 nm Pd Nanoparticles in a Microfluidic Reactor: Insights from in Situ X ray Absorption Fine Structure Spectroscopy and Small-Angle X ray Scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karim, Ayman M.; Al Hasan, Naila M.; Ivanov, Sergei A.

2015-06-11

In this paper we show that the temporal separation of nucleation and growth is not a necessary condition for the colloidal synthesis of monodisperse nanoparticles. The synthesis mechanism of Pd nanoparticles was determined by in situ XAFS and SAXS in a microfluidic reactor capable of millisecond up to an hour time resolution. The SAXS results showed two autocatalytic growth phases, a fast growth phase followed by a very slow growth phase. The steady increase in the number of particles throughout the two growth phases indicates the synthesis is limited by slow continuous nucleation. The transition from fast to slow growthmore » was caused by rapid increase in bonding with the capping agent as shown by XAFS. Based on this fundamental understanding of the synthesis mechanism, we show that 1 nm monodisperse Pd nanoparticles can be synthesized at low temperature using a strong binding capping agent such as trioctylphosphine (TOP).« less

1α,25-Dihydroxyvitamin D3-3β-bromoacetate, a potential cancer therapeutic agent: synthesis and molecular mechanism of action

PubMed Central

Ray, Rahul; Lambert, James R.

2011-01-01

Synthesis of 1α,25-dihydroxyvitamin D3-3β-bromoacetate (1,25(OH)2D3-3-BE), a potential anti-cancer agent is presented. We also report that mechanism of action of 1,25(OH)2D3-3-BE may involve reduction of its catabolism, as evidenced by the reduced and delayed expression of 1α,25-dihydroxyvitamin D3-24-hydroxylase (CYP24) gene in cellular assays. PMID:21392983

Synthesis of Triazole Derivatives of Levoglucosenone As Promising Anticancer Agents: Effective Exploration of the Chemical Space through retro-aza-Michael//aza-Michael Isomerizations.

PubMed

Tsai, Yi-Hsuan; Borini Etichetti, Carla M; Di Benedetto, Carolina; Girardini, Javier E; Martins, Felipe Terra; Spanevello, Rolando A; Suárez, Alejandra G; Sarotti, Ariel M

2018-04-06

The design and synthesis of biomass-derived triazoles and the in vitro evaluation as potential anticancer agents are described. The discovery of base-catalyzed retro-aza-Michael//aza-Michael isomerizations allowed the exploration of the chemical space by affording novel types of triazoles, difficult to obtain otherwise. Following this strategy, 2,4-disubstituted 1,2,3-triazoles could be efficiently obtained from the corresponding 1,4-disubstituted analogues.

Synthesis of Pharmacological Heterocyclic Derivatives Based Surfactants.

PubMed

El-Sayed, Refat; Fadda, Ahmed A

2016-01-01

Synthesis of chromenopyrimidine derivatives and the related fused system carried out by the reaction of chromene derivative 1 with various reagents under suitable reaction conditions. Condensation of stearoyl chloride with these heterocycles, then, propoxylated the products using propylene oxide to produce surface active agents having a twofold capacity as surface and antimicrobial dynamic specialists which may be served in the production of medications, pesticides, beautifying agents or may be utilized as an antimicrobial. Some of the surface properties and antimicrobial activity were resolved.

Primary screen for potential sheep scab control agents.

PubMed

Dunn, J A; Prickett, J C; Collins, D A; Weaver, R J

2016-07-15

The efficacy of potential acaricidal agents were assessed against the sheep scab mite Psoroptes ovis using a series of in vitro assays in modified test arenas designed initially to maintain P. ovis off-host. The mortality effects of 45 control agents, including essential oils, detergents, desiccants, growth regulators, lipid synthesis inhibitors, nerve action/energy metabolism disruptors and ecdysteroids were assessed against adults and nymphs. The most effective candidates were the desiccants (diatomaceous earth, nanoclay and sorex), the growth regulators (buprofezin, hexythiazox and teflubenzuron), the lipid synthesis inhibitors (spirodiclofen, spirotetramat and spiromesifen) and the nerve action and energy metabolism inhibitors (fenpyroximate, spinosad, tolfenpyrad, and chlorantraniliprole). Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

The First Total Synthesis of Sporiolide A

PubMed Central

Chen, Qi; Linhardt, Robert J.

2014-01-01

The first total synthesis of the natural cytotoxic agent sporiolide A has been accomplished from D-glucal in 16 steps with 6.1% overall yield. Carbohydrates were applied as the chiral templates to manipulate the absolute configuration during the synthesis. Pyridinium chlorochromate (PCC)-promoted transformation of the cyclic enol-ether to lactone, followed by Yamaguchi esterification and intramolecular ring closure metathesis, greatly facilitates synthesis of the target compound. PMID:17064018

Timber industry waste-teak ( Tectona grandis Linn.) leaf extract mediated synthesis of antibacterial silver nanoparticles

NASA Astrophysics Data System (ADS)

Devadiga, Aishwarya; Shetty, K. Vidya; Saidutta, M. B.

2015-08-01

The current research article emphasizes efficacious use of teak leaves, an agro -biowaste from world's premier hardwood timber industry, for "green" synthesis of silver nanoparticles (AgNPs). Bioactive compounds of the leaves act as prolific reducing and stabilizing agents in AgNP synthesis. The characterization of the AgNPs synthesized using teak leaves revealed that the particles are spherical with an average size of 28 nm and the presence of bioactive compounds present in teak leaf extract as capping agents on the nanoparticles. A prominent decrease in the content of bioactive compounds such as polyphenols, antioxidants and flavonoids after the biosynthesis of AgNPs signifies that these class of compounds act as reductants and stabilizers during biosynthesis. The biosynthesized silver nanoparticles were also successfully evaluated for their antibacterial characteristics against waterborne pathogens, E. coli and S. aureus, with minimum inhibitory concentration of 25.6 μg/mL. Exploitation of agrowaste resources for synthesis of AgNPs curtails indiscriminate usage of food and commercial plant materials, rather contributing a sustainable way for effective plant waste biomass utilization and management. The biosynthesized AgNps have potential application in water purifiers, antibacterial fabrics, sports wear and in cosmetics as antibacterial agent and the process used for its synthesis being greener is highly beneficial from environmental, energy consumption and economic perspectives.

THE PENETRATION OF REOVIRUS RNA AND INITIATION OF ITS GENETIC FUNCTION IN L-STRAIN FIBROBLASTS

PubMed Central

Silverstein, Samuel C.; Dales, Samuel

1968-01-01

Reovirus type 3 is phagocytized by L cells and rapidly sequestered inside lysosomes. Hydrolases within these organelles are capable of stripping the viral coat proteins, but they fail to degrade the double-stranded RNA genome. These observations support the view that sojourn of reovirus in lysosomes, when the lytic enzymes uncoat its genome, is an obligatory step in the sequence of infection. Although the mechanism for transferring the uncoated RNA out of lysosomes remains to be elucidated, evidence is presented suggesting that progeny genomes are bound to site(s) possessing the fine structure of viral inclusions or factories. It appears that both the synthesis of single- and double-stranded viral RNA and the morphogenesis of progeny virus particles occur in such factories. PMID:19806702

Cytomegalovirus: pathophysiological mechanisms of the cytomegalovirus-induced cellular responses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nokta, M.A.

1986-01-01

Cytomegalovirus (CMV) infection of fibroblasts of human origin is associated with a cascade of morphologic cellular responses which in other systems have been associated with regulation of intracellular free (IF) (Ca/sup + +/). In the present study, the relationship of specific ion fluxes (Ca/sup + +/, Na/sup +/) to the development of cytomegalovirus (CMV)-induced morphologic cellular responses was investigated. An influx of Ca/sup + +/ was observed by the first hour after CMV infection (PI), and total calcium sequestered by infected cells was enhanced by 5 hr Pl. A gradual rise in intracellular free (IF) (Ca/sup + +/) was observedmore » that continued through 48 hour postinfection (hr Pl). The IF (Ca/sup + +/) response to CMV infection was shown to be multiplicity dependent, require viable virus, and occur under conditions consistent with the expression of immediate early CMV genes. Development and progression of cytomegaly was found to be independent of CMV DNA synthesis and appeared to be dependent on the IF (Ca/sup + +/) response. Ca/sup + +/ influx blockers (e.g. verapamil) and cyclic nucleotide modulators (e.g. papaverine) inhibited both Ca/sup + +/ responses and cytomegaly. Quabain-sensitive /sup 86/Rb uptake and sequestering of Ca/sup + +/ increased in parallel with development of cytomegaly. There may be a relationship between Ca/sup + +/ influx, IF (Ca/sup + +/), activation of the Na/sup +//H/sup +/ exchanger, induction of Na/sup +/, Cl/sup -/, HCO/sub 3/ cotransport, Na/sup +/ entry, Na/sup +//K/sup +/ ATPase activity and development of CMV-induced morphologic cellular responses including cytomegaly.« less

The Potential for Carbon Sequestration in the United States

DTIC Science & Technology

2007-09-01

Potential of U.S. Cropland to Sequester Carbon and Mitigate the Greenhouse Effect (Ann Arbor, Mich.: Ann Arbor Press, 1998), pp. 18–21; R.F. Follett and...others, The Potential of U.S. Grazing Land to Sequester Carbon and Mitigate the Greenhouse Effect (Boca Raton, Fla.: CRC Press, 2001), pp. 401–430... the Greenhouse Effect , pp. 18–21; R. Lal and others, “Managing U.S. Cropland to Sequester Carbon in Soil,” Journal of Soil and Water Conservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, Terry F.; Martinelli, Roger E.; Kehl, Steven R.

A series of K d tracer batch experiments were conducted in this paper to assess the absorptive-desorption properties of Biochar as a potential agent to selectively sequester labile soil Cs or otherwise help reduce the uptake of Cs isotopes into plants. A parallel experiment was conducted for strontium. Fine-grained fractionated Woodlands tree Biochar was found to have a relatively high affinity for Cs ions (K d > 100) relative to coral soil (K d < 10) collected from the Marshall Islands. The Biochar material also contains an abundance of K (and Mg). Finally, these findings support a hypothesis that themore » addition of Biochar as a soil amendment may provide a simple yet effective method for reducing soil-to-plant transfer of Cs isotopes in contaminated environments.« less

From nano- to macro-scale: nanotechnology approaches for spatially controlled delivery of bioactive factors for bone and cartilage engineering.

PubMed

Santo, Vítor E; Gomes, Manuela E; Mano, João F; Reis, Rui L

2012-07-01

The field of biomaterials has advanced towards the molecular and nanoscale design of bioactive systems for tissue engineering, regenerative medicine and drug delivery. Spatial cues are displayed in the 3D extracellular matrix and can include signaling gradients, such as those observed during chemotaxis. Architectures range from the nanometer to the centimeter length scales as exemplified by extracellular matrix fibers, cells and macroscopic shapes. The main focus of this review is the application of a biomimetic approach by the combination of architectural cues, obtained through the application of micro- and nanofabrication techniques, with the ability to sequester and release growth factors and other bioactive agents in a spatiotemporal controlled manner for bone and cartilage engineering.

Radioimmunoassays of hidden viral antigens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neurath, A.R.; Strick, N.; Baker, L.

1982-07-01

Antigens corresponding to infectious agents may be present in biological specimens only in a cryptic form bound to antibodies and, thus, may elude detection. We describe a solid-phase technique for separation of antigens from antibodies. Immune complexes are precipitated from serum by polyethylene glycol, dissociated with NaSCN, and adsorbed onto nitrocellulose or polystyrene supports. Antigens remain topographically separated from antibodies after removal of NaSCN and can be detected with radiolabeled antibodies. Genomes from viruses immobilized on nitrocellulose can be identified by nucleic acid hybridization. Nanogram quantities of sequestered hepatitis B surface and core antigens and picogram amounts of hepatitis Bmore » virus DNA were detected. Antibody-bound adenovirus, herpesvirus, and measles virus antigens were discerned by the procedure.« less

On-bead combinatorial synthesis and imaging of chemical exchange saturation transfer magnetic resonance imaging agents to identify factors that influence water exchange.

PubMed

Napolitano, Roberta; Soesbe, Todd C; De León-Rodríguez, Luis M; Sherry, A Dean; Udugamasooriya, D Gomika

2011-08-24

The sensitivity of magnetic resonance imaging (MRI) contrast agents is highly dependent on the rate of water exchange between the inner sphere of a paramagnetic ion and bulk water. Normally, identifying a paramagnetic complex that has optimal water exchange kinetics is done by synthesizing and testing one compound at a time. We report here a rapid, economical on-bead combinatorial synthesis of a library of imaging agents. Eighty different 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid (DOTA)-tetraamide peptoid derivatives were prepared on beads using a variety of charged, uncharged but polar, hydrophobic, and variably sized primary amines. A single chemical exchange saturation transfer image of the on-bead library easily distinguished those compounds having the most favorable water exchange kinetics. This combinatorial approach will allow rapid screening of libraries of imaging agents to identify the chemical characteristics of a ligand that yield the most sensitive imaging agents. This technique could be automated and readily adapted to other types of MRI or magnetic resonance/positron emission tomography agents as well.

Carbon pool and biomass dynamics associated with deforestation, land use, and agricultural abandonment in the neotropics.

PubMed

Kauffman, J Boone; Hughes, R Flint; Heider, Chris

2009-07-01

Current rates of deforestation and the resulting C emissions in the tropics exceed those of secondary forest regrowth and C sequestration. Changing land-use strategies that would maintain standing forests may be among the least expensive of climate change mitigation options. Further, secondary tropical forests have been suggested to have great value for their potential to sequester atmospheric C. These options require an understanding of and capability to quantify C dynamics at landscape scales. Because of the diversity of physical and biotic features of tropical forests as well as approaches and intensities of land uses within the neotropics, there are tremendous differences in the capacity of different landscapes to store and sequester C. Major gaps in our current knowledge include quantification of C pools, rates and patterns of biomass loss following land-cover change, and quantification of the C storage potential of secondary forests following abandonment. In this paper we present a synthesis and further analyses from recent studies that describe C pools, patterns of C decline associated with land use, and rates of C accumulation following secondary-forest establishment--all information necessary for climate-change mitigation options. Ecosystem C pools of Neotropical primary forests minimally range from approximately 141 to 571 Mg/ha, demonstrating tremendous differences in the capacity of different forests to store C. Most of the losses in C and nutrient pools associated with conversion occur when fires are set to remove the slashed forest to prepare sites for crop or pasture establishment. Fires burning slashed primary forests have been found to result in C losses of 62-80% of prefire aboveground pools in dry (deciduous) forest landscapes and 29-57% in wet (evergreen) forest landscapes. Carbon emissions equivalent to the aboveground primary-forest pool arise from repeated fires occurring in the first 4 to 10 years following conversion. Feedbacks of climate change, land-cover change, and increasing habitat fragmentation may result in increases of both the area burned and the total quantity of biomass consumed per unit area by fire. These effects may well limit the capacity for future tropical forests to sequester C and nutrients.

Green Synthesis of Silver Nanoparticles Using Sodium Alginate and Lignosulphonic Acid Blends

NASA Astrophysics Data System (ADS)

Thakur, Amrita; Reddy, Giridhar

2017-08-01

A simple method based on the principles of green chemistry has been developed to synthesize stable silver nanoparticles (AgNP) for possible biomedical applications. Blend of sodium alginate (SA) and lignosulphonic acid (LS) prepared in the ratio of 80/20 mass percent respectively was used as reducing and stabilizing agent. This blend is biocompatible and has shown drug release ability under physiological conditions. Use of blend has an added advantage as LS has the ability to reduce silver while the blend matrix acts as a stabilizing agent. Effect of precursor concentration (AgNO3) and temperature was investigated. Progress of synthesis was monitored using UV-Vis spectroscopy. Higher temperature and lower silver nitrate concentration showed better synthesis of AgNP.

Single Agents with Designed Combination Chemotherapy Potential: Synthesis and Evaluation of Substituted Pyrimido[4,5-b]indoles as Receptor Tyrosine Kinase and Thymidylate Synthase Inhibitors and as Antitumor Agents

PubMed Central

Gangjee, Aleem; Zaware, Nilesh; Raghavan, Sudhir; Ihnat, Michael; Shenoy, Satyendra; Kisliuk, Roy L.

2010-01-01

Combinations of antiangiogenic agents (AAs) with cytotoxic agents have shown significant promise and several such clinical trials are currently underway. We have designed, synthesized and evaluated two compounds that each inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) and platelet derived growth factor receptor-beta (PDGFR-β) for antiangiogenic effects and also inhibit human thymidylate synthase (hTS) for cytotoxic effects in single agents. The synthesis of these compounds involved the nucleophilic displacement of the common intermediate 5-chloro-9H-pyrimido[4,5-b]indole-2,4-diamine with appropriate benzenethiols. The inhibitory potency of both these single agents against VEGFR-2, PDGFR-β and hTS is better than or close to standards. In a COLO-205 xenograft mouse model one of the analogs significantly decreased tumor growth (TGI = 76% at 35 mg/kg), liver metastases and tumor blood vessels compared to a standard drug and to control and thus demonstrated potent tumor growth inhibition, inhibition of metastasis and antiangiogenic effects in vivo. These compounds afford combination chemotherapeutic potential in single agents. PMID:20092323

Identification of an anti-MRSA dihydrofolate reductase inhibitor from a diversity-oriented synthesis.

PubMed

Wyatt, Emma E; Galloway, Warren R J D; Thomas, Gemma L; Welch, Martin; Loiseleur, Olivier; Plowright, Alleyn T; Spring, David R

2008-10-28

The screening of a diversity-oriented synthesis library followed by structure-activity relationship investigations have led to the discovery of an anti-MRSA agent which operates as an inhibitor of Staphylococcus aureus dihydrofolate reductase.

Synthesis, Characterization and Reactivity of a Hexane-Soluble Silver Salt

ERIC Educational Resources Information Center

Stockland, Robert A. Jr.; Wilson, Brian D.; Goodman, Caton C.; Giese, Barret J.; Shrimp, Frederick L., II

2007-01-01

The connectivity of a hexane-soluble silver salt is established by using NMR spectroscopy to describe the synthesis, characterization and reactivity of the salt. The results found hexane-soluble silver to be an effective transfer agent.

Evaluation of the Role of the opgGH Operon in Yersinia pseudotuberculosis and Its Deletion during the Emergence of Yersinia pestis

PubMed Central

Quintard, Kévin; Dewitte, Amélie; Reboul, Angéline; Madec, Edwige; Bontemps-Gallo, Sébastien; Dondeyne, Jacqueline; Marceau, Michaël; Simonet, Michel

2015-01-01

The opgGH operon encodes glucosyltransferases that synthesize osmoregulated periplasmic glucans (OPGs) from UDP-glucose, using acyl carrier protein (ACP) as a cofactor. OPGs are required for motility, biofilm formation, and virulence in various bacteria. OpgH also sequesters FtsZ in order to regulate cell size according to nutrient availability. Yersinia pestis (the agent of flea-borne plague) lost the opgGH operon during its emergence from the enteropathogen Yersinia pseudotuberculosis. When expressed in OPG-negative strains of Escherichia coli and Dickeya dadantii, opgGH from Y. pseudotuberculosis restored OPGs synthesis, motility, and virulence. However, Y. pseudotuberculosis did not produce OPGs (i) under various growth conditions or (ii) when overexpressing its opgGH operon, its galUF operon (governing UDP-glucose), or the opgGH operon or Acp from E. coli. A ΔopgGH Y. pseudotuberculosis strain showed normal motility, biofilm formation, resistance to polymyxin and macrophages, and virulence but was smaller. Consistently, Y. pestis was smaller than Y. pseudotuberculosis when cultured at ≥37°C, except when the plague bacillus expressed opgGH. Y. pestis expressing opgGH grew normally in serum and within macrophages and was fully virulent in mice, suggesting that small cell size was not advantageous in the mammalian host. Lastly, Y. pestis expressing opgGH was able to infect Xenopsylla cheopis fleas normally. Our results suggest an evolutionary scenario whereby an ancestral Yersinia strain lost a factor required for OPG biosynthesis but kept opgGH (to regulate cell size). The opgGH operon was presumably then lost because OpgH-dependent cell size control became unnecessary. PMID:26150539

Synthesis of functional materials in combustion reactions

NASA Astrophysics Data System (ADS)

Zhuravlev, V. D.; Bamburov, V. G.; Ermakova, L. V.; Lobachevskaya, N. I.

2015-12-01

The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating-reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al2O3, YSZ composites, uranium oxides, nickel powder, NiO and NiO: YSZ composite, TiO2, and manganites, cobaltites, and aluminates of rare earth elements.

Synthesis and biological activity of imidazopyridine anticoccidial agents: part I.

PubMed

Scribner, Andrew; Dennis, Richard; Hong, Jean; Lee, Shuliang; McIntyre, Donald; Perrey, David; Feng, Dennis; Fisher, Michael; Wyvratt, Matthew; Leavitt, Penny; Liberator, Paul; Gurnett, Anne; Brown, Chris; Mathew, John; Thompson, Donald; Schmatz, Dennis; Biftu, Tesfaye

2007-01-01

Coccidiosis is the major cause of morbidity and mortality in the poultry industry. Protozoan parasites of the genus Eimeria invade the intestinal lining of the avian host causing tissue pathology, poor weight gain, and in some cases mortality. Resistance to current anticoccidials has prompted the search for new therapeutic agents with potent in vitro and in vivo activity against Eimeria. Antiparasitic activity is due to inhibition of a parasite specific cGMP-dependent protein kinase (PKG). In this study, we present the synthesis and biological activity of imidazo[1,2-a]pyridine anticoccidial agents. From this series, several compounds showed subnanomolar in vitro activity and commercial levels of in vivo activity. However, the potential genotoxicity of these compounds precludes them from further development.

The application of click chemistry in the synthesis of agents with anticancer activity

PubMed Central

Ma, Nan; Wang, Ying; Zhao, Bing-Xin; Ye, Wen-Cai; Jiang, Sheng

2015-01-01

The copper(I)-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry) to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents. PMID:25792812

Rational Tuning of Visual Cycle Modulator Pharmacodynamics

PubMed Central

Kiser, Philip D.; Zhang, Jianye; Badiee, Mohsen; Kinoshita, Junzo; Peachey, Neal S.; Tochtrop, Gregory P.

2017-01-01

Modulators of the visual cycle have been developed for treatment of various retinal disorders. These agents were designed to inhibit retinoid isomerase [retinal pigment epithelium-specific 65 kDa protein (RPE65)], the rate-limiting enzyme of the visual cycle, based on the idea that attenuation of visual pigment regeneration could reduce formation of toxic retinal conjugates. Of these agents, certain ones that contain primary amine groups can also reversibly form retinaldehyde Schiff base adducts, which contributes to their retinal protective activity. Direct inhibition of RPE65 as a therapeutic strategy is complicated by adverse effects resulting from slowed chromophore regeneration, whereas effective retinal sequestration can require high drug doses with potential off-target effects. We hypothesized that the RPE65-emixustat crystal structure could help guide the design of retinaldehyde-sequestering agents with varying degrees of RPE65 inhibitory activity. We found that addition of an isopropyl group to the central phenyl ring of emixustat and related compounds resulted in agents effectively lacking in vitro retinoid isomerase inhibitory activity, whereas substitution of the terminal 6-membered ring with branched moieties capable of stronger RPE65 interaction potentiated inhibition. The isopropyl derivative series produced discernible visual cycle suppression in vivo, albeit much less potently than compounds with a high affinity for the RPE65 active site. These agents were distributed into the retina and formed Schiff base adducts with retinaldehyde. Except for one compound [3-amino-1-(3-isopropyl-5-((2,6,6-trimethylcyclohex-1-en-1-yl)methoxy)phenyl)propan-1-ol (MB-007)], these agents conferred protection against retinal phototoxicity, suggesting that both direct RPE65 inhibition and retinal sequestration are mechanisms of potential therapeutic relevance. PMID:28476927

Inhibition of hepatic lipogenesis by 2-tetradecylglycidic acid.

PubMed

McCune, S A; Nomura, T; Harris, R A

1979-10-01

2-Tetradecylglycidic acid (TDGA), a hypoglycemic agent, has been found to be a very effective inhibitor of de novo fatty acid synthesis by isolated hepatocytes. A comparison was made between the effectiveness of TDGA and 5-(tetradecyloxy)-2-furoic acid (TOFA), a hypolipidemic agent, on the metabolic processes of isolated hepatocytes. These compounds are structurally related and both inhibit fatty acid synthesis; however, they have opposite effects from each other on the oxidation and esterification of fatty acids. TDGA inhibits whereas TOFA stimulates fatty acid oxidation. TDGA stimulates whereas TOFA inhibits fatty acid esterification.

Research on Intelligent Synthesis Environments

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Lobeck, William E.

2002-01-01

Four research activities related to Intelligent Synthesis Environment (ISE) have been performed under this grant. The four activities are: 1) non-deterministic approaches that incorporate technologies such as intelligent software agents, visual simulations and other ISE technologies; 2) virtual labs that leverage modeling, simulation and information technologies to create an immersive, highly interactive virtual environment tailored to the needs of researchers and learners; 3) advanced learning modules that incorporate advanced instructional, user interface and intelligent agent technologies; and 4) assessment and continuous improvement of engineering team effectiveness in distributed collaborative environments.

Research on Intelligent Synthesis Environments

NASA Astrophysics Data System (ADS)

Noor, Ahmed K.; Loftin, R. Bowen

2002-12-01

Four research activities related to Intelligent Synthesis Environment (ISE) have been performed under this grant. The four activities are: 1) non-deterministic approaches that incorporate technologies such as intelligent software agents, visual simulations and other ISE technologies; 2) virtual labs that leverage modeling, simulation and information technologies to create an immersive, highly interactive virtual environment tailored to the needs of researchers and learners; 3) advanced learning modules that incorporate advanced instructional, user interface and intelligent agent technologies; and 4) assessment and continuous improvement of engineering team effectiveness in distributed collaborative environments.

Interfacial Effects and Organization of Inorganic-Organic Composite Solids.

DTIC Science & Technology

1998-05-20

SITU NMR STUDY OF THE HYDROTHERMAL SYNTHESIS OF TEMPLATE-MEDIATED MICROPOROUS ALUMINOPHOSPHATE MATERIALS, Conne M Gersrdin, Pnnccton Univ, Dept...quantitatively characterize the hydrothermal medium while the synthesis proceeds can yield to a better description of the different steps of the...Inorganic-Organic Composite Solids," focused on recent applications in materials synthesis that use structure-directing agents and self-assembly

DNA synthesis inhibitors for the treatment of gastrointestinal cancer.

PubMed

Yasui, Hiroshi; Tsurita, Giichiro; Imai, Kohzoh

2014-11-01

Intensive laboratory, preclinical and clinical studies have identified and validated molecular targets in cancers, leading to a shift toward the development of novel, rationally designed and specific therapeutic agents. However, gastrointestinal cancers continue to have a poor prognosis, largely due to drug resistance. Here, we discuss the current understanding of DNA synthesis inhibitors and their mechanisms of action for the treatment of gastrointestinal malignancies. Conventional agents, including DNA synthesis inhibitors such as fluoropyrimidines and platinum analogs, remain the most effective therapeutics and are the standards against which new drugs are compared. Novel DNA synthesis inhibitors for the treatment of gastrointestinal malignancies include a combination of the antimetabolite TAS-102, which consists of trifluorothymidine with a thymidine phosphorylase inhibitor, and a novel micellar formulation of cisplatin NC-6004 that uses a nanotechnology-based drug delivery system. The challenges of translational cancer research using DNA synthesis inhibitors include the identification of drugs that are specific to tumor cells to reduce toxicity and increase antitumor efficacy, biomarkers to predict pharmacological responses to chemotherapeutic drugs, identification of ways to overcome drug resistance and development of novel combination therapies with DNA synthesis inhibitors and other cancer therapies, such as targeted molecular therapeutics. Here, we discuss the current understanding of DNA synthesis inhibitors and their mechanisms of action for the treatment of gastrointestinal malignancies.

Apparatus for extracting and sequestering carbon dioxide

DOEpatents

Rau, Gregory H [Castro Valley, CA; Caldeira, Kenneth G [Livermore, CA

2010-02-02

An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Method for extracting and sequestering carbon dioxide

DOEpatents

Rau, Gregory H.; Caldeira, Kenneth G.

2005-05-10

A method and apparatus to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said method and apparatus hydrates CO.sub.2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines - application to a formal synthesis of sarizotan.

PubMed

Gati, Wafa; Rammah, Mohamed M; Rammah, Mohamed B; Evano, Gwilherm

2012-01-01

We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.

Green Synthesis of Ag, Cu and AgCu Nanoparticles using Palm Leaves Extract as the Reducing and Stabilizing Agents

NASA Astrophysics Data System (ADS)

Mohamad, N. A. N.; Arham, N. A.; Junaidah, J.; Hadi, A.; Idris, S. A.

2018-05-01

This paper reports the green synthesis of Ag, Cu and AgCu nanoparticles at room temperature using palm leaves extract. The purpose of this study is to eliminate the use of chemicals in the synthesis of nanoparticles and evaluate the efficiency of the palm leaves extract as the reducing and stabilizing agents. The palm leaves extract was added to metal salt solution and continuously stirred until reaction completed. The produced nanoparticles were analyzed using atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analyses revealed that palm leaves extract has efficiently reduced the silver ions, but not the copper ions. During synthesis of AgCu nanoparticles, simultaneous reduction was occurred leading to formation of alloyed nanoparticles. Biomolecules from the palm leaves extract adsorbed on the surface of nanoparticles forming a capping layer thus stabilized the nanoparticles. The produced Ag and Cu nanoparticles were predominantly spherical with the particle size of Cu nanoparticles were larger than Ag nanoparticles. The AgCu nanoparticles closely resembled the Ag nanoparticles due to high Ag content with average size of 13nm. Therefore, palm leaves extract has a potential to be a good reducing and stabilizing agents.

Huperzine a as a pretreatment candidate drug against nerve agent toxicity. (Reannouncement with new availability information)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grunwald, J.; Raveh, L.; Doctor, B.P.

1994-12-31

Huperzine A (HUP) is a naturally-occurring, potent, reversible inhibitor of acetylcholinesterase (AChE) that crosses the blood-brain barrier. To examine its ability to protect against nerve agent poisoning, HUP was administered i.p. to mice, and the s.c. LD50 of soman was determined at various time intervals after pretreatment. Results were compared to those obtained for animals treated with physostigmine. A protective ratio of approximately 2 was maintained for at least 6 hr after a single injection of HUP, without the need for any post-challenge drug therapy. By contrast, pretreatment with physostigmine increased the LD50 of soman by 1.4- to 1.5-fold formore » only up to 90 min. The long-lasting antidotal efficacy displayed by HUP correlated with the time course of the blood-AChE inhibition. The results suggest that the protection of animals by HUP from soman poisoning was achieved by temporarily sequestering the active site region of the physiologically important AChE.« less

Superfund Record of Decision (EPA Region 4): Ciba-Geigy, Washington County, Mcintosh, AL. (Second remedial action), September 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-09-30

The 1,500-acre Ciba-Geigy site is an active chemical manufacturer in an industrial area in McIntosh, Washington County, Alabama. From 1952 to present, Ciba-Geigy, formerly Geigy Chemical Corporation, has produced various chemicals including DDT, laundry products, herbicides, insecticides, agricultural chelating agents, sequestering agents, plastic resins and additives, antioxidants, and specialty chemicals. In 1985, EPA issued a RCRA permit that included a corrective action plan requiring Ciba-Geigy to remove and treat ground water and surface water contamination at the site. In 1987, as part of the corrective action plan requirements, Ciba-Geigy installed an additional wastewater treatment system and ground water monitoring wells.more » The ROD addresses highly contaminated soil and sludge at 10 of the 11 former waste management areas as OU2. The primary contaminants of concern affecting the soil, sludge, and debris are VOCs including benzene and toluene; other organics including PCBs and pesticides (e.g., DDT); and metals including lead. The selected remedial action for the site is included.« less

Engineered Biomimetic Polymers as Tunable Agents for Controlling CaCO₃ Mineralization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chun-Long; Qi, Jiahui; Zuckermann, Ronald N.

2011-01-01

In nature, living organisms use peptides and proteins to precisely control the nucleation and growth of inorganic minerals and sequester CO₂ via mineralization of CaCO₃. Here we report the exploitation of a novel class of sequence-specific non-natural polymers called peptoids as tunable agents that dramatically control CaCO₃ mineralization. We show that amphiphilic peptoids composed of hydrophobic and anionic monomers exhibit both a high degree of control over calcite growth morphology and an unprecedented 23-fold acceleration of growth at a peptoid concentration of only 50 nM, while acidic peptides of similar molecular weight exhibited enhancement factors of only ~2 or less.more » We further show that both the morphology and rate controls depend on peptoid sequence, side-chain chemistry, chain length, and concentration. These findings provide guidelines for developing sequence-specific non-natural polymers that mimic the functions of natural peptides or proteins in their ability to direct mineralization of CaCO₃, with an eye toward their application to sequestration of CO₂ through mineral trapping.« less

Combination of Pim kinase inhibitor, SGI-1776, with bendamustine in B-cell lymphoma

PubMed Central

Yang, Qingshan; Chen, Lisa S; Neelapu, Sattva S.; Gandhi, Varsha

2013-01-01

SGI-1776 is a small molecule Pim kinase inhibitor that primarily targets c-Myc-driven transcription and cap-dependent translation in mantle cell lymphoma (MCL) cells. Bendamustine is an alkylating chemotherapeutic agent approved for use in B-cell lymphoma that is known to induce DNA damage and to initiate response to repair. We hypothesized that while each drug leads to the effects as stated above, combination of these drugs will enhance SGI-1776-induced inhibition of global transcription and translation processes, while promoting bendamustine-triggered decrease of DNA synthesis and DNA damage response in B-cell lymphoma. Both SGI-1776 and bendamustine as single agents effectively induced apoptosis and when used in combination, additive effect in cell killing was observed in MCL cell lines, JeKo-1 and Mino, as well as MCL and splenic marginal zone lymphoma (a type of B-cell lymphoma) primary cells. As expected, SGI-1776 was effective in inducing decrease of global RNA and protein synthesis, while bendamustine significantly inhibited DNA synthesis and generated DNA damage response. When used in combination, effects were intensified in DNA, RNA and protein syntheses compared to single agent treatments. Together, these data provided foundation and suggested feasibility of using Pim kinase inhibitor in combination with chemotherapeutic agents such as bendamustine in B-cell lymphoma. PMID:24290221

ROOM TEMPERATURE BULK AND TEMPLATE-FREE SYNTHESIS OF LEUCOEMARLDINE POLYANILINE NANOFIBERS

EPA Science Inventory

An extremely simple single-step method is described for the bulk synthesis of nanofibers of the electronic polymer polyaniline in fully reduced state (leucoemarldine form) without using any reducing agents, surfactants, and/or large amounts of insoluble templates. Chemical oxida...

ROOM TEMPERATURE BULK AND TEMPLATE-FREE SYNTHESIS OF LEUCOEMARLDINE POLYANILINE NANOFIBERS

EPA Science Inventory

Herein, we describe a simple strategy for the bulk and template-free synthesis of reduced leucoemarldine polyaniline nanofibers size ranging from as low as 10 nm to 50 nm without the use of any reducing agents at room temperature.

Synthesis and characterization of hydrogen-bond acidic functionalized graphene

NASA Astrophysics Data System (ADS)

Yang, Liu; Han, Qiang; Pan, Yong; Cao, Shuya; Ding, Mingyu

2014-05-01

Hexafluoroisopropanol phenyl group functionalized materials have great potential in the application of gas-sensitive materials for nerve agent detection, due to the formation of strong hydrogen-bonding interactions between the group and the analytes. In this paper, take full advantage of ultra-large specific surface area and plenty of carbon-carbon double bonds and hexafluoroisopropanol phenyl functionalized graphene was synthesized through in situ diazonium reaction between -C=C- and p-hexafluoroisopropanol aniline. The identity of the as-synthesis material was confirmed by transmission electron microscopy, Raman spectroscopy, ultraviolet visible spectroscopy, X-ray photoelectron spectroscopy and thermo gravimetric analysis. The synthesis method is simply which retained the excellent physical properties of original graphene. In addition, the novel material can be assigned as an potential candidate for gas sensitive materials towards organophosphorus nerve agent detection.

One-pot synthesis of water soluble iron nanoparticles using rationally-designed peptides and ligand release.

PubMed

Papst, Stefanie; Cheong, Soshan; Banholzer, Moritz J; Brimble, Margaret A; Williams, David E; Tilley, Richard D

2013-05-18

Herein we report the rational design of new phosphopeptides for control of nucleation, growth and aggregation of water-soluble, superparamagnetic iron-iron oxide core-shell nanoparticles. The use of the designed peptides enables a one-pot synthesis that avoids utilizing unstable or toxic iron precursors, organic solvents, and the need for exchange of capping agent after synthesis of the NPs.

Cardio-Pulmonary Response to Shock.

DTIC Science & Technology

1983-09-30

attenuated by inhibition of Tx synthesis . These data indicate that the prostanoids exert direct and indirect acticns in moderating c function...identified as the circulating negative inotropic agent whose production is stimulated by PG synthesis during PEEP. - The large amount of prostacyclin...127 ml - in controls (p < 0.05). The importance of WBC Tx synthesis in the induction of permeability was tested by stimulating isolated WBC with the

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

PubMed Central

Gati, Wafa; Rammah, Mohamed M; Rammah, Mohamed B

2012-01-01

Summary We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions. PMID:23365632

Search for the Universal Ancestors

NASA Technical Reports Server (NTRS)

Hartman, H. (Editor); Lawless, J. G. (Editor); Morrison, P. (Editor)

1985-01-01

By its nature, the study of the origins of life is multidisciplinary, requiring contributions from astronomers, biologists, chemists, geologists, physicists, and many others. Partial answers are provided to many questions about organic chemical evolution and the origin of life. It is observed that the gaps in our knowledge concerning the steps from the nonliving to the living are numerous. Among these gaps are: (1) a solar system formation with its accumulation of raw materials; (2) the synthesis of the life forming monomers, such as the amino acids, nucleotides, and lipids; (3) the condensation of these monomers into useful polymers, such as proteins and nucleic acids; (4) the sequestering of these materials into droplets of proteinoid or membrane-like structures; and (5) the development of a chemical memory (the genetic code) to pass on to the progeny the information acquired.

Synthesis of structurally diverse major groove DNA interstrand crosslinks using three different aldehyde precursors

PubMed Central

Mukherjee, Shivam; Guainazzi, Angelo; Schärer, Orlando D.

2014-01-01

DNA interstrand crosslinks (ICLs) are extremely cytotoxic lesions that block essential cellular processes, such as replication and transcription. Crosslinking agents are widely used in cancer chemotherapy and form an array of structurally diverse ICLs. Despite the clinical success of these agents, resistance of tumors to crosslinking agents, for example, through repair of these lesions by the cellular machinery remains a problem. We have previously reported the synthesis of site-specific ICLs mimicking those formed by nitrogen mustards to facilitate the studies of cellular responses to ICL formation. Here we extend these efforts and report the synthesis of structurally diverse major groove ICLs that induce severe, little or no distortion in the DNA. Our approach employs the incorporation of aldehyde precursors of different lengths into complementary strands and ICL formation using a double reductive amination with a variety of amines. Our studies provide insight into the structure and reactivity parameters of ICL formation by double reductive amination and yield a set of diverse ICLs that will be invaluable for exploring structure–activity relationships in ICL repair. PMID:24782532

HTLV-1 Tax Oncoprotein Subverts the Cellular DNA Damage Response via Binding to DNA-dependent Protein Kinase*S⃞

PubMed Central

Durkin, Sarah S.; Guo, Xin; Fryrear, Kimberly A.; Mihaylova, Valia T.; Gupta, Saurabh K.; Belgnaoui, S. Mehdi; Haoudi, Abdelali; Kupfer, Gary M.; Semmes, O. John

2008-01-01

Human T-cell leukemia virus type-1 is the causative agent for adult T-cell leukemia. Previous research has established that the viral oncoprotein Tax mediates the transformation process by impairing cell cycle control and cellular response to DNA damage. We showed previously that Tax sequesters huChk2 within chromatin and impairs the response to ionizing radiation. Here we demonstrate that DNA-dependent protein kinase (DNA-PK) is a member of the Tax·Chk2 nuclear complex. The catalytic subunit, DNA-PKcs, and the regulatory subunit, Ku70, were present. Tax-containing nuclear extracts showed increased DNA-PK activity, and specific inhibition of DNA-PK prevented Tax-induced activation of Chk2 kinase activity. Expression of Tax induced foci formation and phosphorylation of H2AX. However, Tax-induced constitutive signaling of the DNA-PK pathway impaired cellular response to new damage, as reflected in suppression of ionizing radiation-induced DNA-PK phosphorylation and γH2AX stabilization. Tax co-localized with phospho-DNA-PK into nuclear speckles and a nuclear excluded Tax mutant sequestered endogenous phospho-DNA-PK into the cytoplasm, suggesting that Tax interaction with DNA-PK is an initiating event. We also describe a novel interaction between DNA-PK and Chk2 that requires Tax. We propose that Tax binds to and stabilizes a protein complex with DNA-PK and Chk2, resulting in a saturation of DNA-PK-mediated damage repair response. PMID:18957425

Inhibition of Galectin-1 Sensitizes HRAS-driven Tumor Growth to Rapamycin Treatment.

PubMed

Michael, James V; Wurtzel, Jeremy G T; Goldfinger, Lawrence E

2016-10-01

The goal of this study was to develop combinatorial application of two drugs currently either in active use as anticancer agents (rapamycin) or in clinical trials (OTX008) as a novel strategy to inhibit Harvey RAS (HRAS)-driven tumor progression. HRAS anchored to the plasma membrane shuttles from the lipid ordered (L o ) domain to the lipid ordered/lipid disordered border upon activation, and retention of HRAS at these sites requires galectin-1. We recently showed that genetically enforced L o sequestration of HRAS inhibited mitogen-activated protein kinase (MAPK) signaling, but not phoshatidylinositol 3-kinase (PI3K) activation. Here we show that inhibition of galectin-1 with OTX008 sequestered HRAS in the L o domain, blocked HRAS-mediated MAPK signaling, and attenuated HRAS-driven tumor progression in mice. HRAS-driven tumor growth was also attenuated by treatment with mammalian target of rapamycin (mTOR) inhibitor rapamycin, and this effect was further enhanced in tumors driven by L o -sequestered HRAS. These drugs also revealed bidirectional cross-talk in HRAS pathways. Moreover, dual pathway inhibition with OTX008 and rapamycin resulted in nearly complete ablation of HRAS-driven tumor growth. These findings indicate that membrane microdomain sequestration of HRAS with galectin-1 inhibition, coupled with mTOR inhibition, may support a novel therapeutic approach to treat HRAS-mutant cancer. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Synthesis of functional materials in combustion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuravlev, V. D., E-mail: zhvd@ihim.uran.ru; Bamburov, V. G.; Ermakova, L. V.

2015-12-15

The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating–reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al{sub 2}O{sub 3}, YSZ composites, uranium oxides, nickelmore » powder, NiO and NiO: YSZ composite, TiO{sub 2}, and manganites, cobaltites, and aluminates of rare earth elements.« less

Eco-friendly green synthesis of silver nanoparticles using salmalia malabarica: synthesis, characterization, antimicrobial, and catalytic activity studies

NASA Astrophysics Data System (ADS)

Murali Krishna, I.; Bhagavanth Reddy, G.; Veerabhadram, G.; Madhusudhan, A.

2016-06-01

An economically viable and "green" process has been developed for the synthesis of silver nanoparticles (AgNPs) with an average size of 7 nm using non-toxic and renewable salmalia malabarica gum (SMG) as reducing and capping agent without using any chemical reducing agent. The effect of various parameters such as concentration of SMG and silver nitrate and reaction time for the synthesis of AgNPs was studied. The synthesized AgNPs are systematically characterized by UV/Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Transmission electron microscopy. The resultant SMG-capped AgNPs are highly stable and had significant antibacterial action on both Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus). The catalytic action of the SMG-capped AgNPs to initiate the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4 has also been reported. The kinetics of the reaction was found to be of pseudo-first-order with respect to the 4-NP.

Iron Reverses Impermeable Chelator Inhibition of DNA Synthesis in CCl39 Cells

NASA Astrophysics Data System (ADS)

Alcain, Francisco J.; Low, Hans; Crane, Frederick L.

1994-08-01

Treatment of Chinese hamster lung fibro-blasts (CCl 39 cells) with the impermeable iron(II) chelator bathophenanthroline disulfonate (BPS) inhibits DNA synthesis when cell growth is initiated with growth factors including epidermal growth factor plus insulin, thrombin, or ceruloplasmin, but not with 10% fetal calf serum. The BPS treatment inhibits transplasma membrane electron transport. The treatment leads to release of iron from the cells as determined by BPS iron(II) complex formation over 90 min. Growth factor stimulation of DNA synthesis and electron transport are restored by addition of di- or trivalent iron to the cells in the form of ferric ammonium citrate, ferrous ammonium sulfate, or diferric transferrin. The effect with BPS differs from the inhibition of growth by hydroxyurea, which acts on the ribonucleotide reductase, or diethylenetriaminepentaacetic acid, which is another impermeable chelating agent, in that these agents inhibit growth in 10% fetal calf serum. The BPS effect is consistent with removal of iron from a site on the cell surface that controls DNA synthesis.

Synthesis and characterization of natural and modified antifreeze glycopeptides: glycosylated foldamers.

PubMed

Nagel, Lilly; Plattner, Carolin; Budke, Carsten; Majer, Zsuzsanna; DeVries, Arthur L; Berkemeier, Thomas; Koop, Thomas; Sewald, Norbert

2011-08-01

In Arctic and Antarctic marine regions, where the temperature declines below the colligative freezing point of physiological fluids, efficient biological antifreeze agents are crucial for the survival of polar fish. One group of such agents is classified as antifreeze glycoproteins (AFGP) that usually consist of a varying number (n = 4-55) of [AAT]( n )-repeating units. The threonine side chain of each unit is glycosidically linked to β-D: -galactosyl-(1 → 3)-α-N-acetyl-D: -galactosamine. These biopolymers can be considered as biological antifreeze foldamers. A preparative route for stepwise synthesis of AFGP allows for efficient synthesis. The diglycosylated threonine building block was introduced into the peptide using microwave-enhanced solid phase synthesis. By this versatile solid phase approach, glycosylated peptides of varying sequences and lengths could be obtained. Conformational studies of the synthetic AFGP analogs were performed by circular dichroism experiments (CD). Furthermore, the foldamers were analysed microphysically according to their inhibiting effect on ice recrystallization and influence on the crystal habit.

Mu Opioids and Their Receptors: Evolution of a Concept

PubMed Central

Pan, Ying-Xian

2013-01-01

Opiates are among the oldest medications available to manage a number of medical problems. Although pain is the current focus, early use initially focused upon the treatment of dysentery. Opium contains high concentrations of both morphine and codeine, along with thebaine, which is used in the synthesis of a number of semisynthetic opioid analgesics. Thus, it is not surprising that new agents were initially based upon the morphine scaffold. The concept of multiple opioid receptors was first suggested almost 50 years ago (Martin, 1967), opening the possibility of new classes of drugs, but the morphine-like agents have remained the mainstay in the medical management of pain. Termed mu, our understanding of these morphine-like agents and their receptors has undergone an evolution in thinking over the past 35 years. Early pharmacological studies identified three major classes of receptors, helped by the discovery of endogenous opioid peptides and receptor subtypes—primarily through the synthesis of novel agents. These chemical biologic approaches were then eclipsed by the molecular biology revolution, which now reveals a complexity of the morphine-like agents and their receptors that had not been previously appreciated. PMID:24076545

Effect of both protective and reducing agents in the synthesis of multicolor silver nanoparticles

NASA Astrophysics Data System (ADS)

Rivero, Pedro Jose; Goicoechea, Javier; Urrutia, Aitor; Arregui, Francisco Javier

2013-02-01

In this paper, the influence of variable molar ratios between reducing and loading agents (1:100, 1:50, 1:20, 1:10, 1:5, 1:2, 1:1, 2:1) and between protective and loading agents (0.3:1, 0.75:1, 1.5:1, 3:1, 7.5:1, 30:1, 75:1) in the synthesis of silver nanoparticles by chemical reduction has been evaluated to obtain multicolor nanoparticles with a high stability in time. The protective agent poly(acrylic acid, sodium salt) (PAA) and reducing agent dimethylaminoborane (DMAB) play a key role in the formation of the resultant color. Evolution of the optical absorption bands of the silver nanoparticles as a function of PAA and DMAB molar ratios made it possible to confirm the presence of silver nanoparticles or clusters with a specific shape. The results reveal that a wide range of colors (violet, blue, green, brown, yellow, red, orange), sizes (from nanometer to micrometer), and shapes (cubic, rod, triangle, hexagonal, spherical) can be perfectly tuned by means of a fine control of the PAA and DMAB molar concentrations.

BIOCHEMICAL CHANGES IN TUMOR CELLS AFTER TREATMENT WITH X RAYS, IODOACETATE, HYDROGEN PEROXIDE, AND ETHYLENIMINOBENZOQUINONE (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maass, H.; Kunkel, H.A.

1960-07-01

Results are reported from biochemical investigations on tumor cells after treatment with various physical and chemical agents. If the effects of x rays, iodo-acetate, H/sub 2/O/sub 2/, and several ethyleneimino-benzoquinones on the carbchydrate metabolism are compared, very similar mechanisms of action are observed. These four agents inhibit the dehydrogenation of triosephosphate; but in the case of iodoacetate. an inactivation of triosephosphatedehydrogenase seems to be the reason for this inhibition. In irradiated cells, however, this enzyme is not inactivated, the delay of dehydrogenation being caused mainly by a loss of DPN. After application of cytostatic agents and H/sub 2/O/sub 2/, amore » similar mechanism can be suggested although both agents are also able to block this enzyme. On the other hand, the reaction of the DNA-synthesis is different. Here a much greater sensitivity to x rays and to cytostatic agents than in the case of glycolysis is observed. lodo-acetate, however, inhibits DNA-synthesis in the same range of concentrations in which the glycolysis is blocked. (auth)« less

Chromium removal from ground water by Ion exchange resins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skiadas, P.

1994-05-06

The ground water at several monitoring wells at LLNL has been found to exceed the Surface Water Discharge Limits for Cr(VI). Ion exchange resins have been selected for its removal. A research study is underway to determine which commercial resin is preferred for LLNL`s ground water. The choice of an appropriate resin will be based on Cr(VI) exchange capacity, regeneration efficiency, and pH stabilization. A sequestering agent must also be selected to be used for the elimination of scaling at the treatment facilities. The chemistry of ion exchange resins, and instrumentation and procedures are explained and described in the followingmore » paper. Comparison of the different resins tested lead us to the selection of the most effective one to be used in the treatment facilities.« less

Injectable nanocarriers for biodetoxification

NASA Astrophysics Data System (ADS)

Leroux, Jean-Christophe

2007-11-01

Hospitals routinely treat patients suffering from overdoses of drugs or other toxic chemicals as a result of illicit drug consumption, suicide attempts or accidental exposures. However, for many life-threatening situations, specific antidotes are not available and treatment is largely based on emptying the stomach, administering activated charcoal or other general measures of intoxication support. A promising strategy for managing such overdoses is to inject nanocarriers that can extract toxic agents from intoxicated tissues. To be effective, the nanocarriers must remain in the blood long enough to sequester the toxic components and/or their metabolites, and the toxin bound complex must also remain stable until it is removed from the bloodstream. Here, we discuss the principles that govern the use of injectable nanocarriers in biodetoxification and review the pharmacological performance of a number of different approaches.

Synthesis of tritium-labeled cyadox, a promising antimicrobial growth-promoting agent with high specific activity.

PubMed

Harnud, Sechenchogt; Zhang, Aiqun; Yuan, Zonghui

2018-05-23

Cyadox is a new antimicrobial growth-promoting agent for food-producing animals. Studies on radiolabeled compounds enable the use of sensitive radiometric analytical methods and help in the elucidation of metabolic and elimination pathways. In the present study, 6-[ 3 H]-cyadox with a high specific activity of 2.08 Ci/mmol was prepared by the catalytic bromine-tritium exchange of 4-bromo-2-nitroaniline followed by a three-step microscale synthesis, giving a high yield between 36.16% and 94.75%. Copyright © 2018. Published by Elsevier Ltd.

Perfluorophenyl Azides: New Applications in Surface Functionalization and Nanomaterial Synthesis

PubMed Central

Liu, Li-Hong; Yan, Mingdi

2010-01-01

Conspectus A major challenge in materials science is the ongoing search for coupling agents that are readily synthesized, capable of versatile chemistry, able to easily functionalize materials and surfaces, and efficient in covalently linking organic and inorganic entities. A decade ago, we began a research program investigating perfluorophenylazides (PFPAs) as the coupling agents in surface functionalization and nanomaterial synthesis. The p-substituted PFPAs are attractive heterobifunctional coupling agents because of their two distinct and synthetically distinguishable reactive centers: (i) the fluorinated phenylazide, which is capable of forming stable covalent adducts, and (ii) the functional group R, which can be tailored through synthesis. Two approaches have been undertaken for material synthesis and surface functionalization. The first method involves synthesizing PFPA bearing the first molecule or material with a functional linker R, and then attaching the resulting PFPA to the second material by activating the azido group. In the second approach, the material surface is first functionalized with PFPA via functional center R, and coupling of the second molecule or material is achieved with the surface azido groups. In this Account, we review the design and protocols of the two approaches, providing examples in which PFPA derivatives were successfully used in material surface functionalization, ligand conjugation, and the synthesis of hybrid nanomaterials. The methods developed have proved to be general and versatile, and they are applicable to a wide range of materials (especially those that lack reactive functional groups or are difficult to derivatize) and to various substrates of polymers, oxides, carbon materials, and metal films. The coupling chemistry can be initiated by light, heat, and electrons. Patterned structures can be generated by selectively activating the areas of interest. Furthermore, the process is easy to perform, and light activation occurs in minutes, greatly facilitating the efficiency of the reaction. PFPAs indeed demonstrate many benefits as versatile surface coupling agents and offer opportunities for further exploration. PMID:20690606

RISK REDUCTION VIA GREENER SYNTHESIS OF NOBLE METAL NANOSTRUCTURES AND NANOCOMPOSITES

EPA Science Inventory

Aqueous preparation of nanoparticles using vitamins B2 and C which can function both as reducing and capping agents are described. Bulk and shape-controlled synthesis of noble nanostructures via microwave (MW)-assisted spontaneous reduction of noble metal salts using a-D-glucose,...

Expeditious synthesis of noble metal nanoparticles using Vitamin B12 under microwave irradiation

EPA Science Inventory

A greener synthesis protocol for noble nanometals is developed using vitamin B12 as a reducing and capping agent in conjunction with the use of microwaves. Successful assembly of nanoparticles or microparticles with varied shapes and sizes have been demonstrated. The synthesized ...

In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent.

PubMed

Escárcega-González, Carlos Enrique; Garza-Cervantes, J A; Vázquez-Rodríguez, A; Montelongo-Peralta, Liliana Zulem; Treviño-González, M T; Díaz Barriga Castro, E; Saucedo-Salazar, E M; Chávez Morales, R M; Regalado Soto, D I; Treviño González, F M; Carrazco Rosales, J L; Cruz, Rocío Villalobos; Morones-Ramírez, José Rubén

2018-01-01

One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet-visible, and Fourier transform infrared. We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative ( Escherichia coli , Pseudomonas aeruginosa , and a clinical multidrug-resistant strain of P. aeruginosa ) and Gram-positive ( Bacillus subtilis ) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains.

In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent

PubMed Central

Escárcega-González, Carlos Enrique; Garza-Cervantes, JA; Vázquez-Rodríguez, A; Montelongo-Peralta, Liliana Zulem; Treviño-González, MT; Díaz Barriga Castro, E; Saucedo-Salazar, EM; Chávez Morales, RM; Regalado Soto, DI; Treviño González, FM; Carrazco Rosales, JL; Cruz, Rocío Villalobos; Morones-Ramírez, José Rubén

2018-01-01

Introduction One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains. PMID:29713166

Developing Inhibitors of Translesion DNA Synthesis as Therapeutic Agents against Lung Cancer

DTIC Science & Technology

2015-12-01

normal DNA synthesis. In contrast, pol eta shows a combination of high efficiency and low fidelity when replicating 8-oxo-G. These combined properties...are consistent with a pro- mutagenic role for pol eta when replicating this DNA lesion under cellular conditions. Studies with modified nucleotide...analogs indicate that pol eta relies heavily on hydrogen-bonding interactions during normal and translesion synthesis. However, some nucleobase

Imaging and controlling intracellular reactions: Lysosome transport as a function of diameter and the intracellular synthesis of conducting polymers

NASA Astrophysics Data System (ADS)

Payne, Christine

2014-03-01

Eukaryotic cells are the ultimate complex environment with intracellular chemical reactions regulated by the local cellular environment. For example, reactants are sequestered into specific organelles to control local concentration and pH, motor proteins transport reactants within the cell, and intracellular vesicles undergo fusion to bring reactants together. Current research in the Payne Lab in the School of Chemistry and Biochemistry at Georgia Tech is aimed at understanding and utilizing this complex environment to control intracellular chemical reactions. This will be illustrated using two examples, intracellular transport as a function of organelle diameter and the intracellular synthesis of conducting polymers. Using single particle tracking fluorescence microscopy, we measured the intracellular transport of lysosomes, membrane-bound organelles, as a function of diameter as they underwent transport in living cells. Both ATP-dependent active transport and diffusion were examined. As expected, diffusion scales with the diameter of the lysosome. However, active transport is unaffected suggesting that motor proteins are insensitive to cytosolic drag. In a second example, we utilize intracellular complexity, specifically the distinct micro-environments of different organelles, to carry out chemical reactions. We show that catalase, found in the peroxisomes of cells, can be used to catalyze the polymerization of the conducting polymer PEDOT:PSS. More importantly, we have found that a range of iron-containing biomolecules are suitable catalysts with different iron-containing biomolecules leading to different polymer properties. These experiments illustrate the advantage of intracellular complexity for the synthesis of novel materials.

Quantitation of the rates of hepatic and intestinal cholesterol synthesis in lysosomal acid lipase-deficient mice before and during treatment with ezetimibe.

PubMed

Chuang, Jen-Chieh; Lopez, Adam M; Turley, Stephen D

2017-07-01

Esterified cholesterol (EC) and triglycerides, contained within lipoproteins taken up by cells, are hydrolysed by lysosomal acid lipase (LAL) in the late endosomal/lysosomal (E/L) compartment. The resulting unesterified cholesterol (UC) is transported via Niemann-Pick type C2 and C1 into the cytosolic compartment where it enters a putative pool of metabolically active cholesterol that is utilized in accordance with cellular needs. Loss-of-function mutations in LIPA, the gene encoding LAL, result in dramatic increases in tissue concentrations of EC, a hallmark feature of Wolman disease and cholesteryl ester storage disease (CESD). The lysosomal sequestration of EC causes cells to respond to a perceived deficit of sterol by increasing their rate of cholesterol synthesis, particularly in the liver. A similar compensatory response occurs with treatments that disrupt the enterohepatic movement of cholesterol or bile acids. Here we measured rates of cholesterol synthesis in vivo in the liver and small intestine of a mouse model for CESD given the cholesterol absorption inhibitor ezetimibe from weaning until early adulthood. Consistent with previous findings, this treatment significantly reduced the amount of EC sequestered in the liver (from 132.43±7.35 to 70.07±6.04mg/organ) and small intestine (from 2.78±0.21 to 1.34±0.09mg/organ) in the LAL-deficient mice even though their rates of hepatic and intestinal cholesterol synthesis were either comparable to, or exceeded those in matching untreated Lal -/- mice. These data reveal the role of intestinal cholesterol absorption in driving the expansion of tissue EC content and disease progression in LAL deficiency. Copyright © 2017 Elsevier Inc. All rights reserved.

Mimusops elengi bark extract mediated green synthesis of gold nanoparticles and study of its catalytic activity

NASA Astrophysics Data System (ADS)

Majumdar, Rakhi; Bag, Braja Gopal; Ghosh, Pooja

2016-04-01

The bark extract of Mimusops elengi is rich in different types of plant secondary metabolites such as flavonoids, tannins, triterpenoids and saponins. The present study shows the usefulness of the bark extract of Mimusops elengi for the green synthesis of gold nanoparticles in water at room temperature under very mild conditions. The synthesis of the gold nanoparticles was complete within a few minutes without any extra stabilizing or capping agents and the polyphenols present in the bark extract acted as both reducing as well as stabilizing agents. The synthesized colloidal gold nanoparticles were characterized by HRTEM, surface plasmon resonance spectroscopy and X-ray diffraction studies. The synthesized gold nanoparticles have been used as an efficient catalyst for the reduction of 3-nitrophenol and 4-nitrophenol to their corresponding aminophenols in water at room temperature.

Rapid synthesis of gold and silver nanoparticles using tryptone as a reducing and capping agent

NASA Astrophysics Data System (ADS)

Mehta, Sourabh M.; Sequeira, Marilyn P.; Muthurajana, Harries; D'Souza, Jacinta S.

2018-02-01

Due to its eco-friendliness, recent times have seen an immense interest in the green synthesis of metallic nanoparticles. We present here, a protocol for the rapid and cheap synthesis of Au and Ag nanoparticles (NPs) using 1 mg/ml tryptone (trypsinized casein) as a reducing and capping agent. These nanoparticles are spherical, 10 nm in diameter and relatively monodispersed. The atoms of these NPs are arranged in face-centered cubic fashion. Further, when tested for their cytotoxic property against HeLa and VERO cell lines, gold nanoparticles were more lethal than silver nanoparticles, with a more or less similar trend observed against both Gram-positive and Gram-negative bacteria. On the other hand, the NPs were least cytotoxic against a unicellular alga, Chlamydomonas reinhardtii implying their eco-friendly property.

Synthesis and in vitro evaluation of bone-seeking superparamagnetic iron oxide nanoparticles as contrast agents for imaging bone metabolic activity.

PubMed

Panahifar, Arash; Mahmoudi, Morteza; Doschak, Michael R

2013-06-12

In this article, we report the synthesis and in vitro evaluation of a new class of nonionizing bone-targeting contrast agents based on bisphosphonate-conjugated superparamagnetic iron oxide nanoparticles (SPIONs), for use in imaging of bone turnover with magnetic resonance imaging (MRI). Similar to bone-targeting (99m)Technetium medronate, our novel contrast agent uses bisphosphonates to impart bone-seeking properties, but replaces the former radioisotope with nonionizing SPIONs which enables their subsequent detection using MRI. Our reported method is relatively simple, quick and cost-effective and results in BP-SPIONs with a final nanoparticle size of 17 nm under electron microscopy technique (i.e., TEM). In-vitro binding studies of our novel bone tracer have shown selective binding affinity (around 65%) for hydroxyapatite, the principal mineral of bone. Bone-targeting SPIONs offer the potential for use as nonionizing MRI contrast agents capable of imaging dynamic bone turnover, for use in the diagnosis and monitoring of metabolic bone diseases and related bone pathology.

Synthesis and crystal structures of gold nanowires with Gemini surfactants as directing agents.

PubMed

Xu, Feng; Hou, Hao; Gao, Zhinong

2014-12-15

The preparation of crystalline gold nanowires (NWs) by using gemini surfactants as directing agents through a three-step seed-mediated method is reported. Unlike the nanorods with relatively low aspect ratios (typically below 20) obtained by using cetyltrimethylammonium bromide as a directing agent, the NWs obtained in this investigation can reach up to 4.4 μm, and the largest aspect ratio is calculated to be 210. For this, each of seven different gemini surfactants are utilized as directing agents, and the length and/or aspect ratio of the NWs can be tuned by varying the hydrocarbon chain lengths of the gemini surfactants. Both single and twinned crystalline structures are elucidated by selected-area electron diffraction and high-resolution transmission electron microscopy studies. The use of gemini surfactants not only advances the synthesis of gold nanostructures, but improves the understanding of the growth mechanism for seed-mediated growth. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elution of Uranium and Transition Metals from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Horng-Bin; Kuo, Li-Jung; Wai, Chien M.

2015-11-30

High-surface-area amidoxime and carboxylic acid grafted polymer adsorbents developed at Oak Ridge National Laboratory were tested for sequestering uranium in a flowing seawater flume system at the PNNL-Marine Sciences Laboratory. FTIR spectra indicate that a KOH conditioning process is necessary to remove the proton from the carboxylic acid and make the sorbent effective for sequestering uranium from seawater. The alkaline conditioning process also converts the amidoxime groups to carboxylate groups in the adsorbent. Both Na 2CO 3-H 2O 2 and hydrochloric acid elution methods can remove ~95% of the uranium sequestered by the adsorbent after 42 days of exposure inmore » real seawater. The Na 2CO 3-H 2O 2 elution method is more selective for uranium than conventional acid elution. Iron and vanadium are the two major transition metals competing with uranium for adsorption to the amidoxime-based adsorbents in real seawater.« less

Hypolipidemic, anti-obesity, anti-inflammatory, anti-osteoporotic, and anti-neoplastic properties of amine carboxyboranes.

PubMed Central

Hall, I H; Chen, S Y; Rajendran, K G; Sood, A; Spielvogel, B F; Shih, J

1994-01-01

The amine-carboxyborane derivatives were shown to be effective antineoplastic/cytotoxic agents with selective activity against single-cell and solid tumors derived from murine and human leukemias, lymphomas, sarcomas, and carcinomas. The agents inhibited DNA and RNA synthesis in preference to protein synthesis in L1210 lymphoid leukemia cells. Inosine-monophosphate dehydrogenase apparently is a target site of the compounds; similar effects on phosphoribosyl-pyrophosphate amido transferase, orotidine-monophosphate decarboxylase, and both nucleoside and nucleotide kinases were observed. Deoxyribonucleotide pool levels were reduced in the cells; DNA strand scission was observed with the agents. In rodents, the amine carboxyboranes were potent hypolipidemic agents, lowering both serum cholesterol and triglyceride concentrations, in addition to lowering cholesterol content of very low-density lipoprotein and low-density lipoprotein (LDL) and elevating high-density lipoprotein (HDL) cholesterol concentrations. De novo regulatory enzymes involved in lipid synthesis were also inhibited (e.g., hypocholesterolemic 3-hydroxy-3-methyl-Coenzyme A reductase, acyl-Coenzyme A cholesterol acyltransferase, and sn-glycerol-3-phosphate acyltransferase). Concurrently, the agents modulated LDL and HDL receptor binding, internalization, and degradation, so that less cholesterol was delivered to the plaques and more broken down from esters and conducted to the liver for biliary excretion. Tissue lipids in the aorta wall of the rat were reduced and fewer atherosclerotic morphologic lesions were present in quail aortas after treatment with the agents. Cholesterol resorption from the rat intestine was reduced in the presence of drug. Genetic hyperlipidemic mice demonstrated the same types of reduction after treatment with the agents. The agents would effectively lower lipids in tissue based on the inhibition of regulatory enzymes in pigs. These findings should help improve domestic meat supplies from fowl and pigs. The amine-carboxyboranes were effective anti-inflammatory agents against septic shock, induced edema, pleurisy, and chronic arthritis at 2.5 to 8 mg/kg. Lysosomal and proteolytic enzyme activities were also inhibited. More significantly, the agents were dual inhibitors of prostaglandin cyclooxygenase and 5'-lipoxygenase activities. These compounds also affected cytokine release and white cell migration. Subsequent studies showed that the amine-carboxyboranes were potent anti-osteoporotic agents reducing calcium resorption as well as increasing calcium and proline incorporation into mouse pup calvaria and rat UMR-106 collagen. PMID:7889876

Synthesis and hypocholesterolemic activity of some N-diphenylmethylpiperazine derivatives.

PubMed

Alivert, A; Canals, F; Bonet, J J; Gómez-Parra, V; Sánchez-Alonso, F

1991-09-01

The synthesis and preliminary assays as hypocholesterolemic agents of five N-diphenylmethylpiperazines are described. The evaluations were carried out in hypercholesterolemic mice and two of these compounds were more effective than bezafibrate in the test employed. The di-p-chlorosubstituted compounds showed higher activity than their corresponding dechlorinated analogs.

Green synthesis of nanomaterials and sustainable applications of nano-catalysts

EPA Science Inventory

Green synthesis efforts involving the use of vitamins B1, B2, C, and tea and wine polyphenols which function both as reducing and capping agents will be presented which enables extremely simple, one-pot, green synthetic methods to nanomaterials in water.1a Shape-controlled synth...

Glutathione: A Benign Alternative for the Synthesis of Nanomaterials and Magnetically Separable Organocatalyst in Water

EPA Science Inventory

Glutathione, a completely benign ubiquitous tripeptide, has been used as a reducing agent for the expeditious synthesis of various metal nanoparticles including Ag, Au, Pd and Pt under microwave irradiation conditions in less than one minute. The particles sizes were found to be ...

Gold-silver alloy nanoshells: a new candidate for nanotherapeutics and diagnostics

NASA Astrophysics Data System (ADS)

Gheorghe, Dana E.; Cui, Lili; Karmonik, Christof; Brazdeikis, Audrius; Penaloza, Jose M.; Young, Joseph K.; Drezek, Rebekah A.; Bikram, Malavosklish

2011-10-01

We have developed novel gold-silver alloy nanoshells as magnetic resonance imaging (MRI) dual T 1 (positive) and T 2 (negative) contrast agents as an alternative to typical gadolinium (Gd)-based contrast agents. Specifically, we have doped iron oxide nanoparticles with Gd ions and sequestered the ions within the core by coating the nanoparticles with an alloy of gold and silver. Thus, these nanoparticles are very innovative and have the potential to overcome toxicities related to renal clearance of contrast agents such as nephrogenic systemic fibrosis. The morphology of the attained nanoparticles was characterized by XRD which demonstrated the successful incorporation of Gd(III) ions into the structure of the magnetite, with no major alterations of the spinel structure, as well as the growth of the gold-silver alloy shells. This was supported by TEM, ICP-AES, and SEM/EDS data. The nanoshells showed a saturation magnetization of 38 emu/g because of the presence of Gd ions within the crystalline structure with r 1 and r 2 values of 0.0119 and 0.9229 mL mg-1 s-1, respectively (Au:Ag alloy = 1:1). T 1- and T 2-weighted images of the nanoshells showed that these agents can both increase the surrounding water proton signals in the T 1-weighted image and reduce the signal in T 2-weighted images. The as-synthesized nanoparticles exhibited strong absorption in the range of 600-800 nm, their optical properties being strongly dependent upon the thickness of the gold-silver alloy shell. Thus, these nanoshells have the potential to be utilized for tumor cell ablation because of their absorption as well as an imaging agent.

Gold nanoparticles synthesized by Brassica oleracea (Broccoli) acting as antimicrobial agents against human pathogenic bacteria and fungi

NASA Astrophysics Data System (ADS)

Piruthiviraj, Prakash; Margret, Anita; Krishnamurthy, Poornima Priyadharsani

2016-04-01

Production of antimicrobial agents through the synthesis of gold nanoparticles using green technology has been extensively made consistent by various researchers; yet, this study uses the flower bud's aqueous extracts of Brassica oleracea (Broccoli) as a reducing agent for chloroauric acid (1 mM). After 30 min of incubation, synthesis of gold nanoparticles (AuNps) was observed by a change in extract color from pale yellow to purple color. Synthesis of AuNps was confirmed in UV-visible spectroscopy at the range of approximately 560 nm. The SEM analysis showed the average nanoparticles size of 12-22 nm. The antimicrobial activity of AuNps was analyzed by subjecting it to human pathogenic bacteria (Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumonia) and fungi (Aspergillus flavus, Aspergillus niger and Candida albicans) using disc diffusion method. The broccoli-synthesized AuNps showed the efficient antibacterial and antifungal activity of above-mentioned microbes. It was confirmed that AuNps have the best antimicrobial agent compared to the standard antibiotics (Gentamicin and Fluconazole). When the concentrations of AuNps were increased (10, 25, and 50 µg/ml), the sensitivity zone also increased for all the tested microbes. The synthesized AuNps are capable of rendering high antimicrobial efficacy and, hence, have a great potential in the preparation of drugs used against major bacterial and fungal diseases in humans.

Samarium Diiodide-Mediated Reactions in Total Synthesis

PubMed Central

Nicolaou, K. C.; Ellery, Shelby P.; Chen, Jason S.

2009-01-01

Introduced by Henri Kagan more than three decades ago, samarium diiodide (SmI2) has found increasing applications in chemical synthesis. This single-electron reducing agent has been particularly useful in C–C bond formations, including those found in total synthesis endeavors. This Review highlights selected applications of SmI2 in total synthesis, with special emphasis on novel transformations and mechanistic considerations. The examples discussed are both illustrative of the power of this reagent in complex molecule construction and inspirational for the design of synthetic strategies toward such targets, both natural and designed. PMID:19714695

Native Soil Charcoal as a Model for Designing Biochar for Carbon Sequestration

EPA Science Inventory

Under changing climate a variety of mechanisms for removing carbon from the atmosphere and sequestering it elsewhere are being considered to reduce the forcing of the atmosphere. Amending soils with biochar has been proposed as one long-term means of sequestering carbon originat...

Conservation agricultural management to sequester soil organic carbon

USDA-ARS?s Scientific Manuscript database

Storing carbon (C) in soil as organic matter is not only a viable strategy to sequester CO2 from the atmosphere, but is vital for improving the quality, fertility, and functioning of soil. This presentation describes relevant management approaches to avoid land degradation and foster soil organic C ...

Metamaterial 3D Gain Nanostructures Fabricated Using Direct Laser Writing

DTIC Science & Technology

2015-07-11

oxide (PdO) and selenium powder. To avoid aggregation of the nanoparticles oleic acid and trioctylphosphine were used as stabilizing agents. The...synthesis of the PbSe quantum dots. The precursors used are CdO (Cadmium oxide) and Selenium powder and as stabilizing agent oleic acid was used. The

SYNTHESIS OF HIGHLY FLUORINATED CHLOROFORMATES AND THEIR USE AS DERIVATIZING AGENTS FOR HYDROPHILIC COMPOUNDS AND DRINKING WATER DISINFECTION BY-PRODUCTS

EPA Science Inventory

A rapid, safe and efficient procedure was developed to synthesize perfluorinated chloroformates in the small scale generally required to perform analytical derivatizations. This new family of derivatizing agents allows straightforward derivatization of highly polar compounds, co...

Developing Inhibitors of Translesion DNA Synthesis as Therapeutic Agents Against Lung Cancer

DTIC Science & Technology

2014-10-01

pol eta when replicating damaged DNA. 1S. SUBJECT TERMS: Mutagenesis, DNA polymerases, nucleoside analogs, chemotherapeutic agents 16. SECURITY ...such as polymerase eta, iota , and kappa that are involved in replicating damaged DNA. Our kinetic data obtained under Task 1B indicates that pol eta

Polymer-directed synthesis of metal oxide-containing nanomaterials for electrochemical energy storage

NASA Astrophysics Data System (ADS)

Mai, Yiyong; Zhang, Fan; Feng, Xinliang

2013-12-01

Metal oxide-containing nanomaterials (MOCNMs) of controllable structures at the nano-scale have attracted considerable interest because of their great potential applications in electrochemical energy storage devices, such as lithium-ion batteries (LIBs) and supercapacitors. Among many structure-directing agents, polymers and macromolecules, including block copolymers (BCPs) and graphene, exhibit distinct advantages in the template-assisted synthesis of MOCNMs. In this feature article, we introduce the controlled preparation of MOCNMs employing BCPs and graphene as structure-directing agents. Typical synthetic strategies are presented for the control of structures and sizes as well as the improvement of physical properties and electrochemical performance of MOCNMs in LIBs and supercapacitors.

Polymer-directed synthesis of metal oxide-containing nanomaterials for electrochemical energy storage.

PubMed

Mai, Yiyong; Zhang, Fan; Feng, Xinliang

2014-01-07

Metal oxide-containing nanomaterials (MOCNMs) of controllable structures at the nano-scale have attracted considerable interest because of their great potential applications in electrochemical energy storage devices, such as lithium-ion batteries (LIBs) and supercapacitors. Among many structure-directing agents, polymers and macromolecules, including block copolymers (BCPs) and graphene, exhibit distinct advantages in the template-assisted synthesis of MOCNMs. In this feature article, we introduce the controlled preparation of MOCNMs employing BCPs and graphene as structure-directing agents. Typical synthetic strategies are presented for the control of structures and sizes as well as the improvement of physical properties and electrochemical performance of MOCNMs in LIBs and supercapacitors.

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition.

PubMed

Desbois, Nicolas; Pacquelet, Sandrine; Dubois, Adrien; Michelin, Clément; Gros, Claude P

2015-01-01

The Cu(I)-catalysed Huisgen cycloaddition, known as "click" reaction, has been applied to the synthesis of a range of triazole-linked porphyrin/corrole to DOTA/NOTA derivatives. Microwave irradiation significantly accelerates the reaction. The synthesis of heterobimetallic complexes was easily achieved in up to 60% isolated yield. Heterobimetallic complexes were easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one "cold" metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes are promising contrast agents (CA) in MRI.

Molecular Medicine: Synthesis and In Vivo Detection of Agents for use in Boron Neutron Capture Therapy. Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabalka, G. W.

2005-06-28

The primary objective of the project was the development of in vivo methods for the detection and evaluation of tumors in humans. The project was focused on utilizing positron emission tomography (PET) to monitor the distribution and pharamacokinetics of a current boron neutron capture therapy (BNCT) agent, p-boronophenylalanine (BPA) by labeling it with a fluorine-18, a positron emitting isotope. The PET data was then used to develop enhanced treatment planning protocols. The study also involved the synthesis of new tumor selective BNCTagents that could be labeled with radioactive nuclides for the in vivo detection of boron.

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

PubMed Central

Desbois, Nicolas; Pacquelet, Sandrine; Dubois, Adrien; Michelin, Clément

2015-01-01

Summary The Cu(I)-catalysed Huisgen cycloaddition, known as “click” reaction, has been applied to the synthesis of a range of triazole-linked porphyrin/corrole to DOTA/NOTA derivatives. Microwave irradiation significantly accelerates the reaction. The synthesis of heterobimetallic complexes was easily achieved in up to 60% isolated yield. Heterobimetallic complexes were easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one “cold” metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes are promising contrast agents (CA) in MRI. PMID:26664643

Microwave-assisted synthesis of gold, silver, platinum and palladium nanostructures and their use in electrocatalytic applications.

PubMed

Safavi, Afsaneh; Tohidi, Maryam

2014-09-01

Microwave-assisted ionic liquid method was used for synthesis of various noble metals, such as gold, silver, platinum and palladium nanomaterials. This route does not employ any template agent, surface capping agents or reducing agents. The process is fast, simple and of high yield. Different metal precursors in various ionic liquids media (1-butyl-3-methylimidazolium tetrafluoroborate, octyl pyridinium hexaflurophosphate and 1-octyl-3-methylimidazolium hexaflurophosphate) were applied to produce metal nanomaterials. Silver, platinium and palladium nanoparticles exhibit spherical morphology while nanosheets with high aspect ratio were obtained for gold. These metal nanostructures were incorporated into a carbon ionic liquid electrode to investigate their electrocatalytic properties. It was found that synthesis in different ionic liquids result in different activity. Excellent electrocatalytic effects toward adenine, hydrazine, formaldehyde and ethanol were observed for the modified electrodes with different nanoparticles synthesized in 1-butyl-3-methylimidazolium tetrafluoroborate. The high conductivity, large surface-to-volume ratio and active sites of nanosized metal particles are responsible for their electrocatalytic activity. In contrast, the carbon ionic liquid electrode modified with synthesized metal nanoparticles in octyl pyridinium hexaflurophosphate and 1-octyl-3-methylimidazolium hexaflurophosphate showed negligible activity for detection of these probes.

Self-assembling biomolecular catalysts for hydrogen production

NASA Astrophysics Data System (ADS)

Jordan, Paul C.; Patterson, Dustin P.; Saboda, Kendall N.; Edwards, Ethan J.; Miettinen, Heini M.; Basu, Gautam; Thielges, Megan C.; Douglas, Trevor

2016-02-01

The chemistry of highly evolved protein-based compartments has inspired the design of new catalytically active materials that self-assemble from biological components. A frontier of this biodesign is the potential to contribute new catalytic systems for the production of sustainable fuels, such as hydrogen. Here, we show the encapsulation and protection of an active hydrogen-producing and oxygen-tolerant [NiFe]-hydrogenase, sequestered within the capsid of the bacteriophage P22 through directed self-assembly. We co-opted Escherichia coli for biomolecular synthesis and assembly of this nanomaterial by expressing and maturing the EcHyd-1 hydrogenase prior to expression of the P22 coat protein, which subsequently self assembles. By probing the infrared spectroscopic signatures and catalytic activity of the engineered material, we demonstrate that the capsid provides stability and protection to the hydrogenase cargo. These results illustrate how combining biological function with directed supramolecular self-assembly can be used to create new materials for sustainable catalysis.

Soluble forms of polyQ-expanded huntingtin rather than large aggregates cause endoplasmic reticulum stress

NASA Astrophysics Data System (ADS)

Leitman, Julia; Ulrich Hartl, F.; Lederkremer, Gerardo Z.

2013-11-01

In Huntington’s disease, as in other neurodegenerative diseases, it was initially thought that insoluble protein aggregates are the toxic species. However, growing evidence implicates soluble oligomeric polyglutamine-expanded huntingtin in cytotoxicity. Here we show that pathogenic huntingtin inhibits endoplasmic reticulum (ER)-associated degradation and induces ER stress before its aggregation into visible inclusions. All three branches of the unfolded protein response are activated. ER stress can be compensated by overexpression of p97/VCP, suggesting its sequestration by pathogenic huntingtin as a main cause. Stress correlates with the presence of huntingtin oligomers and is independent of continual huntingtin synthesis. Stress levels, measured in striatal neurons, are stabilized but only slowly subside on huntingtin aggregation into inclusions. Our results can be explained by the constant conversion of huntingtin monomers to toxic oligomers; large aggregates sequester the former, precluding further conversion, whereas pre-existing toxic oligomers are only gradually depleted.

Lipid Droplets: Formation to Breakdown.

PubMed

Meyers, Alex; Weiskittel, Taylor M; Dalhaimer, Paul

2017-06-01

One of the most exciting areas of cell biology during the last decade has been the study of lipid droplets. Lipid droplets allow cells to store non-polar molecules such as neutral lipids in specific compartments where they are sequestered from the aqueous environment of the cell yet can be accessed through regulated mechanisms. These structures are highly conserved, appearing in organisms throughout the phylogenetic tree. Until somewhat recently, lipid droplets were widely regarded as inert, however progress in the field has continued to demonstrate their vast roles in a number of cellular processes in both mitotic and post-mitotic cells. No doubt the increase in the attention given to lipid droplet research is due to their central role in current pressing human diseases such as obesity, type-2 diabetes, and atherosclerosis. This review provides a mechanistic timeline from neutral lipid synthesis through lipid droplet formation and size augmentation to droplet breakdown.

Ni-Fe2O4 nanoparticles as contrast agents for magnetic resonance imaging.

PubMed

Ahmad, Tanveer; Rhee, Ilsu; Hong, Sungwook; Chang, Yongmin; Lee, Jaejun

2011-07-01

Reported herein is the synthesis of a dextran coating on nickel ferrite (Ni-Fe2O4) nanoparticles via chemical coprecipitation. The aqueous solution of the synthesized nanoparticles showed good colloidal stability, and no precipitate was observed 20 months after the synthesis. The coated nanoparticles were found to be cylindrical in shape in the TEM images, and showed a uniform size distribution with an average length and diameter of 17 and 4 nm, respectively. The coated particles were evaluated as potential T1 and T2 contrast agents for MRI. The T1 and T2 relaxations of the hydrogen protons in the water molecules in an aqueous solution of dextran-coated Ni-Fe2O4 nanoparticles were studied. It was found that the T1 relaxivity for the aqueous solution of dextran-coated nanoparticles was slightly greater than that of a commercial Gd-DTPA-BMA contrast agent. The T2 relaxivity, however, was almost twice that of the commercial Gd-DTPA-BMA contrast agent. Animal experimentation also demonstrated that the dextran-coated Ni-Fe2O4 nanoparticles are suitable for use as either T1 or T2 contrast agents in MRI.

Synthesis and Performance of a Biomimetic Indicator for Alkylating Agents.

PubMed

Provencher, Philip A; Love, Jennifer A

2015-10-02

4-(4-Nitrobenzyl)pyridine (NBP) is a colorimetric indicator compound for many types of carcinogenic alkylating agents. Because of the similar reactivity of NBP and guanine in DNA, NBP serves as a DNA model. NBP assays are used in the toxicological screening of pharmaceutical compounds, detection of chemical warfare agents, environmental hygiene technology, preliminary toxicology tests, mutagenicity of medicinal compounds, and other chemical analyses. Nevertheless, the use of NBP as a DNA model suffers from the compound's low water solubility, its lack of reactive oxygen sites, and dissimilar steric encumbrance compared to DNA. We report herein the design and synthesis of NBP derivatives that address some of these issues. These derivatives have been tested in solution and found to be superior in the colorimetric assay of the alkylating anticancer drug cyclophosphamide. The derivatives have also been integrated into a polymeric silica material which changes color upon the exposure to dangerous alkylating agents, such as iodomethane vapor, without the need for an exogenous base. This material modernizes the NBP assay from a time-consuming laboratory analysis to a real-time solid state sensor, which requires neither solvent nor additional reagents and can detect both gas- and solution-phase alkylating agents.

Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

EPA Science Inventory

A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

A Three-Step Synthesis of Benzoyl Peroxide

ERIC Educational Resources Information Center

Her, Brenda; Jones, Alexandra; Wollack, James W.

2014-01-01

Benzoyl peroxide is used as a bleaching agent for flour and whey processing, a polymerization initiator in the synthesis of plastics, and the active component of acne medication. Because of its simplicity and wide application, benzoyl peroxide is a target molecule of interest. It can be affordably synthesized in three steps from bromobenzene using…

Drug Development Against Parasitic Diseases: Synthesis of the Antimalarial Agent Qinghaosu and Analogs.

DTIC Science & Technology

A stereoselective total synthesis of (+)- artemisinin has been improved from 18 steps to 13 steps with a resultant 12-fold increase in the overall...yield. A new class of tricyclic analogs of artemisinin has been discovered that possess good in vitro antimalarial activity. U.S. and foreign patents

Toxin-Induced Activation of Rat Hepatocyte Prostaglandin Synthesis and Phospholipid Metabolism

DTIC Science & Technology

1989-12-22

rate-limiting step in prostaglandin synthesis, which is controlled by balancing deacylating and reacylating activities (4,5). Several natural toxins...1980) Nature 288, 597- 600. 4. Ferber, E. and Ecker, B. (1984) Agents and Actions 15, 27-28. 5. Flesch, I., Ecker, B. and Ferber, E. (1984) Eur. J

Green synthesis of Se/Ru alloy nanoparticles using gallic acid and evaluation of theiranti-invasive effects in HeLa cells.

PubMed

Zhou, Yanhui; Xu, Meng; Liu, Yanan; Bai, Yan; Deng, Yuqian; Liu, Jie; Chen, Lanmei

2016-08-01

Methods for the synthesis of nanoparticles (NPs) for biomedical applications ideally involve the use of nontoxic reducing and capping agents, and more importantly, enable control over the shape and size of the particles. As such, we used gallic acid (GA) as both a reducing and a capping agent in a simple and "green" synthesis of stable Se/Rualloy NPs (GA-Se/RuNPs). The diameter and morphology of the Se/Ru alloy NPs were regulated by GA concentration, and the presence of Ru was found to be a key factor in regulating and controlling the size of GA-Se/RuNPs. Moreover, GA-Se/RuNPs suppressed HeLa cell proliferation through the induction of apoptosis at concentrations that were nontoxic in normal cells. Furthermore, GA-Se/RuNPs effectively inhibited migration and invasion in HeLa cells via the inhibition of MMP-2 and MMP-9 proteins. Our findings confirm that bimetallic (Se/Ru) NPs prepared via GA-mediated synthesis exhibit enhanced anticancer effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Force fields for describing the solution-phase synthesis of shape-selective metal nanoparticles

NASA Astrophysics Data System (ADS)

Zhou, Ya; Al-Saidi, Wissam; Fichthorn, Kristen

2013-03-01

Polyvinylpyrrolidone (PVP) and polyethylene oxide (PEO) are structure-directing agents that exhibit different performance in the polyol synthesis of Ag nanostructures. The success of these structure-directing agents in selective nanostructure synthesis is often attributed to their selective binding to Ag(100) facets. We use first-principles, density-functional theory (DFT) calculations in a vacuum environment to show that PVP has a stronger preference to bind to Ag(100) than to Ag(111), whereas PEO exhibits much weaker selectivity. To understand the role of solvent in the surface-sensitive binding, we develop classical force fields to describe the interactions of the structure-directing (PVP and PEO) and solvent (ethylene glycol) molecules with various Ag substrates. We parameterize the force fields through force-and-energy matching to DFT results using simulated annealing. We validate the force fields by comparisons to DFT and experimental binding energies. Our force fields reproduce the surface-sensitive binding predicted by DFT calculations. Molecular dynamics simulations based on these force fields can be used to reveal the role of solvent, polymer chain length, and polymer concentration in the selective synthesis of Ag nanostructures.

Ascorbyl coumarates as multifunctional cosmeceutical agents that inhibit melanogenesis and enhance collagen synthesis.

PubMed

Kwak, Jun Yup; Park, Soojin; Seok, Jin Kyung; Liu, Kwang-Hyeon; Boo, Yong Chool

2015-09-01

L-Ascorbic acid (AA) and p-coumaric acid (p-CA) are naturally occurring antioxidants that are known to enhance collagen synthesis and inhibit melanin synthesis, respectively. The purpose of this study was to examine hybrid compounds between AA and p-CA as multifunctional cosmeceutical agents. Ascorbyl 3-p-coumarate (A-3-p-C), ascorbyl 2-p-coumarate (A-2-p-C), and their parent compounds were tested for their effects on cellular melanin synthesis and collagen synthesis. At 100 μM, A-3-p-C and A-2-p-C decreased melanin content of human dermal melanocytes stimulated by L-tyrosine, by 65 and 59%, respectively, compared to 11% inhibition of AA and 70% inhibition of p-CA. A-3-p-C and A-2-p-C were less effective than p-CA but more effective than AA at inhibiting tyrosinase activity. A-3-p-C and A-2-p-C were more effective than p-CA at inhibiting the autoxidation of L-3,4-dihydroxyphenylalanine. At 100-300 μM, A-3-p-C and A-2-p-C augmented collagen release from human dermal fibroblasts by 120-144% and 125-191%, respectively, compared to 126-133% increase of AA and 120-146% increase of p-CA. They increased procollagen type I C-peptide release (A-3-p-C, and A-2-p-C) like AA, and decreased matrix metalloproteinase 1 level (A-2-p-C) like p-CA, implicating that they might regulate collagen metabolism by multiple mechanisms. This study suggests that A-3-p-C and A-2-p-C could be used as multifunctional cosmeceutical agents for the attenuation of certain aspects of skin aging.

Bacilysin from Bacillus amyloliquefaciens FZB42 Has Specific Bactericidal Activity against Harmful Algal Bloom Species

PubMed Central

Wu, Liming; Wu, Huijun; Chen, Lina; Xie, Shanshan; Zang, Haoyu; Borriss, Rainer

2014-01-01

Harmful algal blooms, caused by massive and exceptional overgrowth of microalgae and cyanobacteria, are a serious environmental problem worldwide. In the present study, we looked for Bacillus strains with sufficiently strong anticyanobacterial activity to be used as biocontrol agents. Among 24 strains, Bacillus amyloliquefaciens FZB42 showed the strongest bactericidal activity against Microcystis aeruginosa, with a kill rate of 98.78%. The synthesis of the anticyanobacterial substance did not depend on Sfp, an enzyme that catalyzes a necessary processing step in the nonribosomal synthesis of lipopeptides and polyketides, but was associated with the aro gene cluster that is involved in the synthesis of the sfp-independent antibiotic bacilysin. Disruption of bacB, the gene in the cluster responsible for synthesizing bacilysin, or supplementation with the antagonist N-acetylglucosamine abolished the inhibitory effect, but this was restored when bacilysin synthesis was complemented. Bacilysin caused apparent changes in the algal cell wall and cell organelle membranes, and this resulted in cell lysis. Meanwhile, there was downregulated expression of glmS, psbA1, mcyB, and ftsZ—genes involved in peptidoglycan synthesis, photosynthesis, microcystin synthesis, and cell division, respectively. In addition, bacilysin suppressed the growth of other harmful algal species. In summary, bacilysin produced by B. amyloliquefaciens FZB42 has anticyanobacterial activity and thus could be developed as a biocontrol agent to mitigate the effects of harmful algal blooms. PMID:25261512

Transthyretin Sequesters Amyloid β Protein and Prevents Amyloid Formation

NASA Astrophysics Data System (ADS)

Schwarzman, Alexander L.; Gregori, Luisa; Vitek, Michael P.; Lyubski, Sergey; Strittmatter, Warren J.; Enghilde, Jan J.; Bhasin, Ramaninder; Silverman, Josh; Weisgraber, Karl H.; Coyle, Patricia K.; Zagorski, Michael G.; Talafous, Joseph; Eisenberg, Moises; Saunders, Ann M.; Roses, Allen D.; Goldgaber, Dmitry

1994-08-01

The cardinal pathological features of Alzheimer disease are depositions of aggregated amyloid β protein (Aβ) in the brain and cerebrovasculature. However, the Aβ is found in a soluble form in cerebrospinal fluid in healthy individuals and patients with Alzheimer disease. We postulate that sequestration of Aβ precludes amyloid formation. Failure to sequester Aβ in Alzheimer disease may result in amyloidosis. When we added Aβ to cerebrospinal fluid of patients and controls it was rapidly sequestered into stable complexes with transthyretin. Complexes with apolipoprotein E, which has been shown to bind Aβ in vitro, were not observed in cerebrospinal fluid. Additional in vitro studies showed that both purified transthyretin and apolipoprotein E prevent amyloid formation.

Detection of Alkylating Agents using Electrical and Mechanical Means

NASA Astrophysics Data System (ADS)

Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Tal, Shay; Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir; Eichen, Yoav

2011-08-01

Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

Synthesis and evaluation of 1-amino-6-halo-β-carbolines as antimalarial and antiprion agents.

PubMed

Thompson, Mark J; Louth, Jennifer C; Little, Susan M; Jackson, Matthew P; Boursereau, Yohan; Chen, Beining; Coldham, Iain

2012-04-01

Malaria is one of the world's most devastating parasitic diseases, causing almost one million deaths each year. Growing resistance to classical antimalarial drugs, such as chloroquine, necessitates the discovery of new therapeutic agents for successful control of this global disease. Here, we report the synthesis of some 6-halo-β-carbolines as analogues of the potent antimalarial natural product, manzamine A, retaining its heteroaromatic core whilst providing compounds with much improved synthetic accessibility. Two compounds displayed superior activity to chloroquine itself against a resistant Plasmodium falciparum strain, identifying them as promising leads for future development. Furthermore, in line with previous reports of similarities in antimalarial and antiprion effects of aminoaryl-based antimalarial agents, the 1-amino-β-carboline libraries were also found to possess significant bioactivity against a prion-infected cell line. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of altered sink:source ratio on photosynthetic metabolism of source leaves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plaut, Z.; Mayoral, M.L.; Reinhold, L.

When seven crop species were grown under identical environmental conditions, decreased sink:source ratio led to a decreased photosynthetic rate within 1 to 3 days in Cucumis sativus L., Gossypium hirsutum L., and Raphanus sativus L., but not in Capsicum annuum L., Solanum melongena L., Phaseolus vulgaris L., or Ricinus communis L. The decrease was not associated with stomatal closure. In cotton and cucumbers, sink removal led to an increase in starch and sugar content, in glucose 6-phosphate and fructose 6-phosphate pools, and in the proportion of /sup 14/C detected in sugar phosphates and UDPglucose following /sup 14/CO/sub 2/ supply. Whenmore » mannose was supplied to leaf discs to sequester cytoplasmic inorganic phosphate, promotion of starch synthesis, and inhibition of CO/sub 2/ fixation, were observed in control discs, but not in discs from treated plants. Phosphate buffer reduced starch synthesis in the latter, but not the former discs. The findings suggest that sink removal led to a decreased ratio inorganic phosphate:phosphorylated compounds. In beans /sup 14/C in sugar phosphates increased following sink removal, but without sucrose accumulation, suggesting tighter feedback control of sugar level. Starch accumulated to higher levels than in the other plants, but CO/sub 2/ fixation rate was constant for several days.« less

Technical Improvements to an Absorbing Supergel for Radiological Decontamination in Tropical Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaminski, Michael D.; Mertz, Carol J.; Kivenas, Nadia

Argonne National Laboratory (Argonne) developed a superabsorbing gel-based process (SuperGel) for the decontamination of cesium from concrete and other porous building materials. Here, we report on results that tested the gel decontamination technology on specific concrete and ceramic formulations from a coastal city in Southeast Asia, which may differ significantly from some U.S. sources. Results are given for the evaluation of americium and cesium sequestering agents that are commercially available at a reasonable cost; the evaluation of a new SuperGel formulation that combines the decontamination properties of cesium and americium; the variation of the contamination concentration to determine the effectsmore » on the decontamination factors with concrete, tile, and brick samples; and pilot-scale testing (0.02–0.09 m2 or 6–12 in. square coupons).« less

Non-Systemic Drugs: A Critical Review

PubMed Central

Charmot, Dominique

2012-01-01

Non-systemic drugs act within the intestinal lumen without reaching the systemic circulation. The first generation included polymeric resins that sequester phosphate ions, potassium ions, or bile acids for the treatment of electrolyte imbalances or hypercholesteremia. The field has evolved towards non-absorbable small molecules or peptides targeting luminal enzymes or transporters for the treatment of mineral metabolism disorders, diabetes, gastrointestinal (GI) disorders, and enteric infections. From a drug design and development perspective, non-systemic agents offer novel opportunities to address unmet medical needs while minimizing toxicity risks, but also present new challenges, including developing a better understanding and control of non-transcellular leakage pathways into the systemic circulation. The pharmacokinetic-pharmacodynamic relationship of drugs acting in the GI tract can be complex due to the variability of intestinal transit, interaction with chyme, and the complex environment of the surface epithelia. We review the main classes of non-absorbable agents at various stages of development, and their therapeutic potential and limitations. The rapid progress in the identification of intestinal receptors and transporters, their functional characterization and role in metabolic and inflammatory disorders, will undoubtedly renew interest in the development of novel, safe, non-systemic therapeutics. PMID:22300258

Synthesis in plants and plant extracts of silver nanoparticles with potent antimicrobial properties: current status and future prospects.

PubMed

Mashwani, Zia-ur-Rehman; Khan, Tariq; Khan, Mubarak Ali; Nadhman, Akhtar

2015-12-01

Synthesis of silver nanoparticles by plants and plant extracts (green synthesis) has been developed into an important innovative biotechnology, especially in the application of such particles in the control of pathogenic bacteria. This is a safer technology, biologically and environmentally, than synthesis of silver nanoparticles by chemical or physical methods. Plants are preferable to microbes as agents for the synthesis of silver nanoparticles because plants do not need to be maintained in cell culture. The antibacterial activity of bionanoparticles has been extensively explored during the past decade. This review examines studies published in the last decade that deal with the synthesis of silver nanoparticles in plants and their antibacterial activity.

Fire and the distribution and uncertainty of carbon sequestered as above-ground tree biomass in Yosemite and Sequoia & Kings Canyon National Parks

USGS Publications Warehouse

Lutz, James A.; Matchett, John R.; Tarnay, Leland W.; Smith, Douglas F.; Becker, Kendall M.L.; Furniss, Tucker J.; Brooks, Matthew L.

2017-01-01

Fire is one of the principal agents changing forest carbon stocks and landscape level distributions of carbon, but few studies have addressed how accurate carbon accounting of fire-killed trees is or can be. We used a large number of forested plots (1646), detailed selection of species-specific and location-specific allometric equations, vegetation type maps with high levels of accuracy, and Monte Carlo simulation to model the amount and uncertainty of aboveground tree carbon present in tree species (hereafter, carbon) within Yosemite and Sequoia & Kings Canyon National Parks. We estimated aboveground carbon in trees within Yosemite National Park to be 25 Tg of carbon (C) (confidence interval (CI): 23–27 Tg C), and in Sequoia & Kings Canyon National Park to be 20 Tg C (CI: 18–21 Tg C). Low-severity and moderate-severity fire had little or no effect on the amount of carbon sequestered in trees at the landscape scale, and high-severity fire did not immediately consume much carbon. Although many of our data inputs were more accurate than those used in similar studies in other locations, the total uncertainty of carbon estimates was still greater than ±10%, mostly due to potential uncertainties in landscape-scale vegetation type mismatches and trees larger than the ranges of existing allometric equations. If carbon inventories are to be meaningfully used in policy, there is an urgent need for more accurate landscape classification methods, improvement in allometric equations for tree species, and better understanding of the uncertainties inherent in existing carbon accounting methods.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanders, L.K.; Xian, W.; Guaqueta, C.

The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozymemore » complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held together by arrays of lysozyme at the threefold interstitial sites of the actin sublattice to marginally stable complexes in which lysozyme resides at twofold bridging sites between actin. The reduced stability arises from strongly reduced partitioning of salt between the complex and the surrounding solution. Changes in the stability of actin-lysozyme complexes are of biomedical interest because their formation has been reported to contribute to the persistence of airway infections in cystic fibrosis by sequestering antimicrobials such as lysozyme. We present x-ray microscopy results that argue for the existence of actin-lysozyme complexes in cystic fibrosis sputum and demonstrate that, for a wide range of salt conditions, charge-reduced lysozyme is not sequestered in ordered complexes while retaining its bacterial killing activity.« less

Sodium ion channel alkaloid resistance does not vary with toxicity in aposematic Dendrobates poison frogs: An examination of correlated trait evolution

PubMed Central

Wang, Ian J.

2018-01-01

Spatial heterogeneity in the strength or agents of selection can lead to geographic variation in ecologically important phenotypes. Many dendrobatid frogs sequester alkaloid toxins from their diets and often exhibit fixed mutations at NaV1.4, a voltage-gated sodium ion channel associated with alkaloid toxin resistance. Yet previous studies have noted an absence of resistance mutations in individuals from several species known to sequester alkaloid toxins, suggesting possible intraspecific variation for alkaloid resistance in these species. Toxicity and alkaloid profiles vary substantially between populations in several poison frog species (genus Dendrobates) and are correlated with variation in a suite of related traits such as aposematic coloration. If resistance mutations are costly, due to alterations of channel gating properties, we expect that low toxicity populations will have reduced frequencies and potentially even the loss of resistance alleles. Here, we examine whether intraspecific variation in toxicity in three dendrobatid frogs is associated with intraspecific variation in alleles conferring toxin resistance. Specifically, we examine two species that display marked variation in toxicity throughout their native ranges (Dendrobates pumilio and D. granuliferus) and one species with reduced toxicity in its introduced range (D. auratus). However, we find no evidence for population-level variation in alkaloid resistance at NaV1.4. In fact, contrary to previous studies, we found that alkaloid resistance alleles were not absent in any populations of these species. All three species exhibit fixed alkaloid resistance mutations throughout their ranges, suggesting that these mutations are maintained even when alkaloid sequestration is substantially reduced. PMID:29534110

A Mouse Click Away: Internet Resources for Students in Crisis in Geographically Isolated or Self-Sequestered Communities

ERIC Educational Resources Information Center

Gary, Juneau Mahan

2010-01-01

The impact, incidence, prevalence, and severity of violence and trauma adversely affect students academically, behaviorally, emotionally, and socially. For students residing in geographically isolated or self-sequestered communities, trauma may be exacerbated when school counselors may be unprepared to respond effectively and timely because…

Process for sequestering carbon dioxide and sulfur dioxide

DOEpatents

Maroto-Valer, M Mercedes [State College, PA; Zhang, Yinzhi [State College, PA; Kuchta, Matthew E [State College, PA; Andresen, John M [State College, PA; Fauth, Dan J [Pittsburgh, PA

2009-10-20

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Can greening of aquaculture sequester blue carbon?

PubMed

Ahmed, Nesar; Bunting, Stuart W; Glaser, Marion; Flaherty, Mark S; Diana, James S

2017-05-01

Globally, blue carbon (i.e., carbon in coastal and marine ecosystems) emissions have been seriously augmented due to the devastating effects of anthropogenic pressures on coastal ecosystems including mangrove swamps, salt marshes, and seagrass meadows. The greening of aquaculture, however, including an ecosystem approach to Integrated Aquaculture-Agriculture (IAA) and Integrated Multi-Trophic Aquaculture (IMTA) could play a significant role in reversing this trend, enhancing coastal ecosystems, and sequestering blue carbon. Ponds within IAA farming systems sequester more carbon per unit area than conventional fish ponds, natural lakes, and inland seas. The translocation of shrimp culture from mangrove swamps to offshore IMTA could reduce mangrove loss, reverse blue carbon emissions, and in turn increase storage of blue carbon through restoration of mangroves. Moreover, offshore IMTA may create a barrier to trawl fishing which in turn could help restore seagrasses and further enhance blue carbon sequestration. Seaweed and shellfish culture within IMTA could also help to sequester more blue carbon. The greening of aquaculture could face several challenges that need to be addressed in order to realize substantial benefits from enhanced blue carbon sequestration and eventually contribute to global climate change mitigation.

Immobilization of Iron Nanoparticles on Multi Substrates and Its Reduction Removal of Chromium (VI) from Waste Streams

EPA Science Inventory

This article describes the in-situ synthesis and immobilization of iron nanoparticles on several substrates at room temperature using NaBH4 as a reducing agent and ascorbic acid as capping agent. The method is very effective in protecting iron nanoparticles from air oxidation for...

Impact of Environmental Conditions (pH, Ionic Strength, And Electrolyte Type) On The Surface Charge And Aggregation Of Silver Nanoparticles Suspensions

EPA Science Inventory

The impact of capping agents and environmental conditions (pH, ionic strength, and background electrolytes) on surface charge and aggregation potential of silver nanoparticles (AgNPs) suspensions were investigated. Capping agents are chemicals used in the synthesis of nanopartic...

The in situ synthesis and application of silver nanoparticles as an antimicrobial agent for cotton fibers

USDA-ARS?s Scientific Manuscript database

The application of sliver (Ag) as an antimicrobial agent dates back to the 1800s. Silver systems release positively charged silver ions (Ag+), when in aqueous media, that disrupts negatively charged surfaces of bacterial membranes, thus resulting in bacterial death. Its antimicrobial utility is not ...

WORKSHOP ON EMERGING INFECTIOUS DISEASE AGENTS AND ISSUES ASSOCIATED WITH ANIMAL MANURES, BIOSOLIDS, AND OTHER SIMILAR BY-PRODUCTS: THE REST OF THE STORY

EPA Science Inventory

This presentation will:

Discuss the purpose of the workshop
Discussion publication of "Contemporary Perspectives on Infectious Disease Agents in Sewage Sludge and Manure.
Present Table of Contents
Discuss summary
Discuss synthesis document

Synthesis and biological evaluation of novel gigantol derivatives as potential agents in prevention of diabetic cataract

USDA-ARS?s Scientific Manuscript database

As a continuation of our efforts directed towards the development of natural anti-diabetic cataract agents, gigantol was isolated from Herba dendrobii and was found to inhibit both aldose reductase (AR) and inducible nitric oxide synthase (iNOS) activity, which play a significant role in the develop...

Simple sol-gel synthesis and characterization of new CoTiO3/CoFe2O4 nanocomposite by using liquid glucose, maltose and starch as fuel, capping and reducing agents.

PubMed

Ansari, Fatemeh; Sobhani, Azam; Salavati-Niasari, Masoud

2018-03-15

The sol-gel auto-combustion technique is an effective method for the synthesis of the composites. In this research for the first time, CoTiO 3 /CoFe 2 O 4 nanocomposites are successfully synthesized via a new sol-gel auto-combustion technique. The glucose, maltose and starch are used as fuel, capping and reducing agents, also the optimal reducing agent is chosen. The effects of quantity of reducing agent, molar ratio of Ti:Co, calcination temperature and time on the morphology, particle size, magnetic property, purity and phase of the nanocomposites are investigated. XRD patterns show formation of CoTiO 3 /CoFe 2 O 4 spherical nanoparticles with nearly evenly distribution, when the molar ratio of Co/Ti is 1:1. EDS analysis confirm results of XRD. The magnetic behavior of the nanocomposites is studied by VSM. The nanocomposites exhibit a high coercivity at room temperature. Copyright © 2017 Elsevier Inc. All rights reserved.

Infectious Mononucleosis

PubMed Central

Joncas, J.

1967-01-01

A short review of past and recent works pertinent to the etiology and pathogenesis of infectious mononucleosis is presented. Epidemiological studies have led to the elaboration of hypotheses concerning the etiology, the length of the incubation period and the mode of transmission of the disease. An unusual type of infectious mononucleosis of rickettsial origin has been reported by Japanese workers. Studies of accidental and experimental transmission suggest that more than one agent may give rise to the same disease. Isolation attempts in tissue cultures have been unrewarding except for the uncovering of possible agents by interference and immunofluorescence. The atypical lymphocyte is the site of increased RNA and DNA synthesis. It does not seem to be involved in antibody synthesis. The heterophile agglutinins and other mononucleosis-associated antibodies apparently account for only part of the excess 19S antibody material found in mononucleosis sera. The origin and function of these antibodies and of the atypical lymphocyte are the subject of speculation. The final elucidation of the pathogenesis of the disease and the confirmation of the reviewed hypotheses are all dependent on the eventual discovery of the elusive etiological agent(s) of infectious mononucleosis. PMID:5336955

Intelligent Agents for Design and Synthesis Environments: My Summary

NASA Technical Reports Server (NTRS)

Norvig, Peter

1999-01-01

This presentation gives a summary of intelligent agents for design synthesis environments. We'll start with the conclusions, and work backwards to justify them. First, an important assumption is that agents (whatever they are) are good for software engineering. This is especially true for software that operates in an uncertain, changing environment. The "real world" of physical artifacts is like that: uncertain in what we can measure, changing in that things are always breaking down, and we must interact with non-software entities. The second point is that software engineering techniques can contribute to good design. There may have been a time when we wanted to build simple artifacts containing little or no software. But modern aircraft and spacecraft are complex, and rely on a great deal of software. So better software engineering leads to better designed artifacts, especially when we are designing a series of related artifacts and can amortize the costs of software development. The third point is that agents are especially useful for design tasks, above and beyond their general usefulness for software engineering, and the usefulness of software engineering to design.

Sulfonated macro-RAFT agents for the surfactant-free synthesis of cerium oxide-based hybrid latexes.

PubMed

Garnier, Jérôme; Warnant, Jérôme; Lacroix-Desmazes, Patrick; Dufils, Pierre-Emmanuel; Vinas, Jérôme; van Herk, Alex

2013-10-01

Three types of amphiphatic macro-RAFT agents were employed as compatibilizers to promote the polymerization reaction at the surface of nanoceria for the synthesis of CeO2-based hybrid latexes. Macro-RAFT copolymers and terpolymers were first synthesized employing various combinations of butyl acrylate as a hydrophobic monomer and acrylic acid (AA) and/or 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as hydrophilic monomers. After characterizing the adsorption of these macro-RAFT agents at the cerium oxide surface by UV-visible spectrometry, emulsion copolymerization reactions of styrene and methyl acrylate were then carried out in the presence of the surface-modified nanoceria. Dynamic Light Scattering and cryo-Transmission Electron Microscopy were employed to confirm the hybrid structure of the final CeO2/polymer latexes, and proved that the presence of acrylic acid units in amphiphatic macro-RAFT agents enabled an efficient formation of hybrid structures, while the presence of AMPS units, when combined with AA units, resulted in a better distribution of cerium oxide nanoclusters between latex particles. Copyright © 2013 Elsevier Inc. All rights reserved.

Density Control of Multi-Agent Systems with Safety Constraints: A Markov Chain Approach

NASA Astrophysics Data System (ADS)

Demirer, Nazli

The control of systems with autonomous mobile agents has been a point of interest recently, with many applications like surveillance, coverage, searching over an area with probabilistic target locations or exploring an area. In all of these applications, the main goal of the swarm is to distribute itself over an operational space to achieve mission objectives specified by the density of swarm. This research focuses on the problem of controlling the distribution of multi-agent systems considering a hierarchical control structure where the whole swarm coordination is achieved at the high-level and individual vehicle/agent control is managed at the low-level. High-level coordination algorithms uses macroscopic models that describes the collective behavior of the whole swarm and specify the agent motion commands, whose execution will lead to the desired swarm behavior. The low-level control laws execute the motion to follow these commands at the agent level. The main objective of this research is to develop high-level decision control policies and algorithms to achieve physically realizable commanding of the agents by imposing mission constraints on the distribution. We also make some connections with decentralized low-level motion control. This dissertation proposes a Markov chain based method to control the density distribution of the whole system where the implementation can be achieved in a decentralized manner with no communication between agents since establishing communication with large number of agents is highly challenging. The ultimate goal is to guide the overall density distribution of the system to a prescribed steady-state desired distribution while satisfying desired transition and safety constraints. Here, the desired distribution is determined based on the mission requirements, for example in the application of area search, the desired distribution should match closely with the probabilistic target locations. The proposed method is applicable for both systems with a single agent and systems with large number of agents due to the probabilistic nature, where the probability distribution of each agent's state evolves according to a finite-state and discrete-time Markov chain (MC). Hence, designing proper decision control policies requires numerically tractable solution methods for the synthesis of Markov chains. The synthesis problem has the form of a Linear Matrix Inequality Problem (LMI), with LMI formulation of the constraints. To this end, we propose convex necessary and sufficient conditions for safety constraints in Markov chains, which is a novel result in the Markov chain literature. In addition to LMI-based, offline, Markov matrix synthesis method, we also propose a QP-based, online, method to compute a time-varying Markov matrix based on the real-time density feedback. Both problems are convex optimization problems that can be solved in a reliable and tractable way, utilizing existing tools in the literature. A Low Earth Orbit (LEO) swarm simulations are presented to validate the effectiveness of the proposed algorithms. Another problem tackled as a part of this research is the generalization of the density control problem to autonomous mobile agents with two control modes: ON and OFF. Here, each mode consists of a (possibly overlapping) finite set of actions, that is, there exist a set of actions for the ON mode and another set for the OFF mode. We give formulation for a new Markov chain synthesis problem, with additional measurements for the state transitions, where a policy is designed to ensure desired safety and convergence properties for the underlying Markov chain.

New agents for prostate cancer.

PubMed

Agarwal, N; Di Lorenzo, G; Sonpavde, G; Bellmunt, J

2014-09-01

The therapeutic landscape of metastatic castration-resistant prostate cancer (mCRPC) has been revolutionized by the arrival of multiple novel agents in the past 2 years. Immunotherapy in the form of sipuleucel-T, androgen axis inhibitors, including abiraterone acetate and enzalutamide, a chemotherapeutic agent, cabazitaxel, and a radiopharmaceutical, radium-223, have all yielded incremental extensions of survival and have been recently approved. A number of other agents appear promising in early studies, suggesting that the armamentarium against castrate-resistant prostate cancer is likely to continue to expand. Emerging androgen pathway inhibitors include androgen synthesis inhibitors (TAK700), androgen receptor inhibitors (ARN-509, ODM-201), AR DNA binding domain inhibitors (EPI-001), selective AR downregulators or SARDs (AZD-3514), and agents that inhibit both androgen synthesis and receptor binding (TOK-001/galeterone). Promising immunotherapeutic agents include poxvirus vaccines and CTLA-4 inhibitor (ipilimumab). Biologic agents targeting the molecular drivers of disease are also being investigated as single agents, including cabozantinib (Met and VEGFR2 inhibitor) and tasquinimod (angiogenesis and immune modulatory agent). Despite the disappointing results seen from studies evaluating docetaxel in combination with other agents, including GVAX, anti-angiogentic agents (bevacizumab, aflibercept, lenalinomide), a SRC kinase inhibitor (dasatinib), endothelin receptor antagonists (atrasentan, zibotentan), and high-dose calcitriol (DN-101), the results from the trial evaluating docetaxel in combination with the clusterin antagonist, custirsen, are eagerly awaited. New therapeutic hurdles consist of discovering new targets, understanding resistance mechanisms, the optimal sequencing and combinations of available agents, as well as biomarkers predictive for benefit. Novel agents targeting bone metastases are being developed following the success of zoledronic acid and denosumab. Finally, all of these modalities do not appear curative, suggesting that clinical trial enrollment and a better understanding of biology remain of paramount importance. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Progress in the development of gelling agents for improved culturability of microorganisms

PubMed Central

Das, Nabajit; Tripathi, Naveen; Basu, Srijoni; Bose, Chandra; Maitra, Susmit; Khurana, Sukant

2015-01-01

Gelling agents are required for formulating both solid and semisolid media, vital for the isolation of microorganisms. Gelatin was the first gelling agent to be discovered but it soon paved the way for agar, which has far superior material qualities. Source depletion, issues with polymerase-chain-reaction and inability to sustain extermophiles etc., necessitate the need of other gelling agents. Many new gelling agents, such as xantham gum, gellan gum, carrageenan, isubgol, and guar gum have been formulated, raising the hopes for the growth of previously unculturable microorganisms. We evaluate the progress in the development of gelling agents, with the hope that our synthesis would help accelerate research in the field. PMID:26257708

Drug Development of the Antimalarial Agent Artemisinin: Total Synthesis, Analog Synthesis, and Structure-Activity Relationship Studies

DTIC Science & Technology

1990-08-15

16. SUPPLEMENTARY NOTATION 17 COSATi CODES FiELD 07 06 CROUP 03 01 SUB-GROUP IB SUBJECT TERMS (Cont/nu* on rtvtnt if ntctiwy *ne identity b ...number of requisite substituents resulted in the synthesis of ring cleaved analogs and partial structures of artemisinin: (+)-C/D, (+)-A/ B /C, (+)-A/C...in the preparation of the unstable aldehyde 2, and in commendable fashion others have employed an enol ether photo-oxygenation as entry to that

Total Synthesis of Jiadifenolide**

PubMed Central

Paterson, Ian; Xuan, Mengyang; Dalby, Stephen M

2014-01-01

As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small-molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium-mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters. PMID:24861364

GREEN AND CONTROLLED SYNTHESIS OF GOLD AND PLATINUM NANOMATERIALS USING VITAMIN B2: DENSITY-ASSISTED SELF-ASSEMBLY OF NANOSPHERES, WIRES AND RODS

EPA Science Inventory

For the first time, we report density-assisted self-assembly and efficient synthesis of gold (Au) and platinum (Pt) nanospheres, nanowires and nanorods using vitamin B₂ (riboflavin) without employing any special capping or dispersing agent at room temperature; this env...

Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

EPA Science Inventory

For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag) and palladium (Pd), nanospheres, nanowires and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4) or hydroxylamine hydro...

EFFECT OF POLY (ETHYLENE GLYCOL) ON THE FORMATION OF NANOSTRUCTURES: A FACILE SUSTAINABLE APPROACH FOR THE SYNTHESIS OF SILVER NANORODS USING MICROWAVE IRRADIATION

EPA Science Inventory

Bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) under microwave irradiation is reported. The formation of nanorods or particulate morphology is dependent on the PEG concentration. This greener method uses no surfactants or reducing agents and employs a b...

Green chemistry approach for the synthesis of biocompatible graphene

PubMed Central

Gurunathan, Sangiliyandi; Han, Jae Woong; Kim, Jin-Hoi

2013-01-01

Background Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. One of the most common methods for preparation of graphene is chemical exfoliation of graphite using powerful oxidizing agents. Generally, graphene is synthesized through deoxygenation of graphene oxide (GO) by using hydrazine, which is one of the most widespread and strongest reducing agents. Due to the high toxicity of hydrazine, it is not a promising reducing agent in large-scale production of graphene; therefore, this study focused on a green or sustainable synthesis of graphene and the biocompatibility of graphene in primary mouse embryonic fibroblast cells (PMEFs). Methods Here, we demonstrated a simple, rapid, and green chemistry approach for the synthesis of reduced GO (rGO) from GO using triethylamine (TEA) as a reducing agent and stabilizing agent. The obtained TEA reduced GO (TEA-rGO) was characterized by ultraviolet (UV)–visible absorption spectroscopy, X-ray diffraction (XRD), particle size dynamic light scattering (DLS), scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). Results The transition of graphene oxide to graphene was confirmed by UV–visible spectroscopy. XRD and SEM were used to investigate the crystallinity of graphene and the surface morphologies of prepared graphene respectively. The formation of defects further supports the functionalization of graphene as indicated in the Raman spectrum of TEA-rGO. Surface morphology and the thickness of the GO and TEA-rGO were analyzed using AFM. The presented results suggest that TEA-rGO shows significantly more biocompatibility with PMEFs cells than GO. Conclusion This is the first report about using TEA as a reducing as well as a stabilizing agent for the preparation of biocompatible graphene. The proposed safe and green method offers substitute routes for large-scale production of graphene for several biomedical applications. PMID:23940417

One-pot wet-chemical co-reduction synthesis of bimetallic gold-platinum nanochains supported on reduced graphene oxide with enhanced electrocatalytic activity

NASA Astrophysics Data System (ADS)

Chen, De-Jun; Zhang, Qian-Li; Feng, Jin-Xia; Ju, Ke-Jian; Wang, Ai-Jun; Wei, Jie; Feng, Jiu-Ju

2015-08-01

In this work, a simple, rapid and facile one-pot wet-chemical co-reduction method is developed for synthesis of bimetallic Au-Pt alloyed nanochains supported on reduced graphene oxide (Au-Pt NCs/RGO), in which caffeine is acted as a capping agent and a structure-directing agent, while no any seed, template, surfactant or polymer involved. The as-prepared nanocomposites display enlarged electrochemical active surface area, significantly enhanced catalytic activity and better stability for methanol and ethylene glycol oxidation, compared with commercial Pt-C (Pt 50 wt%), PtRu-C (Pt 30 wt% and Ru 15 wt%) and Pt black.

Cucurbit[7]uril as a tool in the green synthesis of gold nanoparticles.

PubMed

Premkumar, Thathan; Geckeler, Kurt E

2010-12-03

A simple, green, one-pot synthesis of gold nanoparticles was achieved through the reaction of an aqueous mixture of potassium tetrachloroaurate(III) and the macrocycle cucurbit[7]uril in the presence of sodium hydroxide at room temperature without introducing any kind of traditional reducing agents and/or external energy. The as-prepared gold nanoparticles showed catalytic activity for the reduction reaction of 4-nitrophenol in the presence of NaBH(4), which has been established by visual inspection and UV/Vis spectroscopy. This report is the first for the preparation of gold nanoparticles using cucurbit[7]uril in aqueous media through chemical reduction without employing conventional reducing agents and/or external energy.

Genetically modified Medicago truncatula lacking calcium oxalate has increased calcium bioavailability and partially rescues vitamin D receptor knockout mice phenotypes

USDA-ARS?s Scientific Manuscript database

How the distribution and sequestered form of plant macro/micro-nutrients influence their bioavailability, and ultimately impact human health, is poorly understood. The legume Medicago truncatula has a portion of its tissue calcium sequestered in the form of the calcium oxalate crystal, which reduces...

Minimum cost strategies for sequestering carbon in forests.

Treesearch

Darius M. Adams; Ralph J. Alig; Bruce A. McCarl; John M. Callaway; Steven M. Winnett

1999-01-01

This paper examines the costs of meeting explicit targets for increments of carbon sequestered in forests when both forest management decisions and the area of forests can be varied. Costs are estimated as welfare losses in markets for forest and agricultural products. Results show greatest change in management actions when targets require large near-term flux...

Meeting global policy commitments carbon sequestration and southern pine forests

Treesearch

Kurt H. Johnsen; David N. Wear; R. Oren; R.O. Teskey; Felipe Sanchez; Rodney E. Will; John Butnor; D. Markewitz; D. Richter; T. Rials; H.L. Allen; J. Seiler; D. Ellsworth; Christopher Maier; G. Katul; P.M. Dougherty

2001-01-01

In managed forests, the amount of carbon further sequestered will be determined by (1) the increased amount of carbon in standing biomass (resulting from land-use changes and increased productivity); (2) the amount of recalcitrant carbon remaining below ground at the end of rotations; and (3) the amount of carbon sequestered in products created from harvested wood....

Biocompatible, Biodegradable, and Enzymatic-Cleavable MRI Contrast Agents for Early Detection of Bone Metastatic Breast Cancer

DTIC Science & Technology

2012-04-01

detection of bone metastasis from breast cancer. The proposed imaging agent is consist of bone targeting moiety of Asp8 and MRI imaging moiety of DOTA ...peptide onto DOTA followed by Gd complexation was performed to achieve the proposed imaging agent. Non-targeting and CTSK-insensitive controls were...synthesis (SPPS) strategy, and purified by preparative HPLC. The chemical structures of peptides were shown below. Peptides reacted with DOTA -NHS

Monodisperse spindle-like FeWO{sub 4} nanoparticles: Controlled hydrothermal synthesis and enhanced optical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Jinxue; Zhou, Xiaoyu; Lu, Yibin

2012-12-15

Monodisperse FeWO{sub 4} nanoparticles with specific spindle-like morphology have been synthesized in the presence of citric acid through hydrothermal process. In the synthesis route, citric acid played four roles such as the reducing agent, chelating regents, structure-directing agent and stabilizing agents. In addition, the morphology of FeWO{sub 4} was dramatically tuned by the pH value of the precursor medium. The optical properties of FeWO{sub 4} were investigated with UV-Vis spectra and photoluminescence spectroscopy. The photocatalytic experiments demonstrated that the decomposition efficiency of the monodisperse spindle-like FeWO{sub 4} nanoparticles is 74% after 30 min of UV irradiation, which displayed remarkable enhancedmore » photodegradation activity compared with ordinary FeWO{sub 4} sample (57%) and normal TiO{sub 2} photocatalysts P-25 (56%). - Monodisperse spindle-like FeWO{sub 4} nanoparticles with enhanced photocatalytic activities. Highlights: Black-Right-Pointing-Pointer Monodisperse spindle-like FeWO{sub 4} were synthesized with hydrothermal method. Black-Right-Pointing-Pointer Citric acid plays key roles in the hydrothermal synthesis. Black-Right-Pointing-Pointer Their morphology can be tuned with pH value of the precursor medium. Black-Right-Pointing-Pointer They show enhanced photocatalytic activities with irradiation of UV light.« less

Facile One-Pot Synthesis of Tellurium Nanorods as Antioxidant and Anticancer Agents.

PubMed

Huang, Wei; Wu, Hualian; Li, Xiaoling; Chen, Tianfeng

2016-08-19

Nanorods have been utilized in targeted therapy, controlled release, molecular diagnosis, and molecule imaging owing to their large surface area and optical, magnetic, electronic, and structural properties. However, low stability and complex synthetic methods have substantially limited the application of tellurium nanorods for use as antioxidant and anticancer agents. Herein, a facile one-pot synthesis of functionalized tellurium nanorods (PTNRs) by using a hydrothermal synthetic system with a polysaccharide-protein complex (PTR), which was extracted from Pleurotus tuber-regium, as a capping agent is described. PTNRs remained stable in water and in phosphate-buffered saline and exhibited high hemocompatibility. Interestingly, these nanorods possessed strong antioxidant activity for scavenging 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS(.+) ) and 2,2-diphenyl-1-picrylhydrazylhydrate (DPPH) free radicals and demonstrated novel anticancer activities. However, these nanorods exhibited low cytotoxicity toward normal human cells. In addition, the PTNRs effectively induced a decrease in the mitochondrial membrane potential in a dose-dependent manner, which indicated that mitochondrial dysfunction might play an important role in PTNR-induced apoptosis. Therefore, this study provides a one-pot strategy for the facile synthesis of tellurium nanorods with novel antioxidant and anticancer application potentials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microbial glycolipoprotein-capped silver nanoparticles as emerging antibacterial agents against cholera.

PubMed

Gahlawat, Geeta; Shikha, Sristy; Chaddha, Baldev Singh; Chaudhuri, Saumya Ray; Mayilraj, Shanmugam; Choudhury, Anirban Roy

2016-02-01

With the increased number of cholera outbreaks and emergence of multidrug resistance in Vibrio cholerae strains it has become necessary for the scientific community to devise and develop novel therapeutic approaches against cholera. Recent studies have indicated plausibility of therapeutic application of metal nano-materials. Among these, silver nanoparticles (AgNPs) have emerged as a potential antimicrobial agent to combat infectious diseases. At present nanoparticles are mostly produced using physical or chemical techniques which are toxic and hazardous. Thus exploitation of microbial systems could be a green eco-friendly approach for the synthesis of nanoparticles having similar or even better antimicrobial activity and biocompatibility. Hence, it would be worth to explore the possibility of utilization of microbial silver nanoparticles and their conjugates as potential novel therapeutic agent against infectious diseases like cholera. The present study attempted utilization of Ochrobactrum rhizosphaerae for the production of AgNPs and focused on investigating their role as antimicrobial agents against cholera. Later the exopolymer, purified from the culture supernatant, was used for the synthesis of spherical shaped AgNPs of around 10 nm size. Further the exopolymer was characterized as glycolipoprotein (GLP). Antibacterial activity of the novel GLP-AgNPs conjugate was evaluated by minimum inhibitory concentration, XTT reduction assay, scanning electron microscopy (SEM) and growth curve analysis. SEM studies revealed that AgNPs treatment resulted in intracellular contents leakage and cell lysis. The potential of microbially synthesized nanoparticles, as novel therapeutic agents, is still relatively less explored. In fact, the present study first time demonstrated that a glycolipoprotein secreted by the O. rhizosphaerae strain can be exploited for production of AgNPs which can further be employed to treat infectious diseases. Although this type of polymer has been obtained earlier from marine fungi and bacteria, none of these reports have studied the role of this polymer in AgNPs synthesis and its application in cholera therapy. Interestingly, the microbial GLP-capped AgNPs exhibited antibacterial activity against V. cholerae comparable to ciprofloxacin. Thus the present study may open up new avenues for development of novel therapeutic agents for treatment of infectious diseases. Graphical abstract Development of novel therapeutic agents for treatment of cholera.

The influence of human neutrophils on N-nitrosodimethylamine (NDMA) synthesis.

PubMed

Jabłoński, Jakub; Jabłońska, Ewa; Iwanowska, Jolanta; Marcińczyk, Magda; Moniuszko-Jakoniuk, Janina

2006-01-01

N-nitrozodimethyloamine (NDMA) is a carcinogenic compound that can be formed in vivo. NDMA is synthesized from precursors-amines and nitrosating agents. Nitrosating agents are formed through the reaction of oxide, reactive oxygen species and nitric oxide (NO). Human neutrophils (PMN) are an important source of the most reactive oxygen species as well as of the nitric oxide. The increase in oxygen metabolism of PMN can lead to the increase nitrosating agent and nitroso-forms. Inflammatory process is associated with locally decreased pH that may favor nitrosation reaction. In the present study, we estimated the NDMA synthesis by LPS-stimulated PMN in the presence of the iNOS inhibitor--N-nitro-L-arginine methyl ester (L-NAME). In the nitrosation reaction dimethylamine (DMA) was used as substrat. The viability of the cells was measured by cytometric method. NDMA concentrations the culture media was measured by GCMS method. NO production was estimated by Griess's method. Expression of iNOS was determined by western blotting. Results obtained showed that DMA nitrosation is most effective in pH between 3-4.5. Nonstimulated PMN produced lower concentrations of NO than LPS-stimulated cells (1.27 microg/cm3 and 1.57 microg/cm3, respectively). In the culture of nonstimulated PMN supplemented with DMA, there was NDMA (mean--0.99 ng/cm3). In the culture of LPS-stimulated PMN in the presence of DMA, the concentration of NDMA was higher than in the culture of nonstimulated PMN (median--1.45 ng/cm3). In the supernatants of cells incubated without DMA and with DMA, LPS and L-NAME, no NDMA was detected. These results indicate that PMN can be one of sources of nitrosating agents and can play a role in endogenous NDMA synthesis. Stimulation of PMN can lead to the increase of NDMA concentration following the increase of NO production. Different pathological conditions associated with PMN activation as well as the decreased pH may favor endogenous NDMA synthesis.

Soil organic carbon sequestration in cotton production systems of the southeastern United States: a review.

PubMed

Causarano, H J; Franzluebbers, A J; Reeves, D W; Shaw, J N

2006-01-01

Past agricultural management practices have contributed to the loss of soil organic carbon (SOC) and emission of greenhouse gases (e.g., carbon dioxide and nitrous oxide). Fortunately, however, conservation-oriented agricultural management systems can be, and have been, developed to sequester SOC, improve soil quality, and increase crop productivity. Our objectives were to (i) review literature related to SOC sequestration in cotton (Gossypium hirsutum L.) production systems, (ii) recommend best management practices to sequester SOC, and (iii) outline the current political scenario and future probabilities for cotton producers to benefit from SOC sequestration. From a review of 20 studies in the region, SOC increased with no tillage compared with conventional tillage by 0.48 +/- 0.56 Mg C ha(-1) yr(-1) (H(0): no change, p < 0.001). More diverse rotations of cotton with high-residue-producing crops such as corn (Zea mays L.) and small grains would sequester greater quantities of SOC than continuous cotton. No-tillage cropping with a cover crop sequestered 0.67 +/- 0.63 Mg C ha(-1) yr(-1), while that of no-tillage cropping without a cover crop sequestered 0.34 +/- 47 Mg C ha(-1) yr(-1) (mean comparison, p = 0.04). Current government incentive programs recommend agricultural practices that would contribute to SOC sequestration. Participation in the Conservation Security Program could lead to government payments of up to Dollars 20 ha(-1). Current open-market trading of C credits would appear to yield less than Dollars 3 ha(-1), although prices would greatly increase should a government policy to limit greenhouse gas emissions be mandated.

Differential Regulation of Angiogenesis using Degradable VEGF-Binding Microspheres

PubMed Central

Belair, David G.; Miller, Michael J.; Wang, Shoujian; Darjatmokon, Soesiawati R.; Binder, Bernard Y.K.; Sheibani, Nader; Murphy, William L.

2016-01-01

Vascular endothelial growth factor (VEGF) spatial and temporal activity must be tightly controlled during angiogenesis to form perfusable vasculature in a healing wound. The native extracellular matrix (ECM) regulates growth factor activity locally via sequestering, and researchers have used ECM-mimicking approaches to regulate the activity of VEGF in cell culture and in vivo. However, the impact of dynamic, affinity-mediated growth factor sequestering has not been explored in detail with biomaterials. Here, we sought to modulate VEGF activity dynamically over time using poly(ethylene glycol) microspheres containing VEGF-binding peptides (VBPs) and exhibiting varying degradation rates. The degradation rate of VBP microspheres conferred a differential ability to up- or down-regulate VEGF activity in culture with primary human endothelial cells. VBP microspheres with fast-degrading crosslinks reduced VEGF activity and signaling, while VBP microspheres with no inherent degradability sequestered and promoted VEGF activity in culture with endothelial cells. VBP microspheres with degradable crosslinks significantly reduced neovascularization in vivo, but neither non-degradable VBP microspheres nor bolus delivery of soluble VBP reduced neovascularization. The covalent incorporation of VBP to degradable microspheres was required to reduce neovascularization in a mouse model of choroidal neovascularization in vivo, which demonstrates a potential clinical application of degradable VBP microspheres to reduce pathological angiogenesis. The results herein highlight the ability to modulate the activity of a sequestered growth factor by changing the crosslinker identity within PEG hydrogel microspheres. The insights gained here may instruct the design and translation of affinity-based growth factor sequestering biomaterials for regenerative medicine applications. PMID:27061268

Social Skills Interventions for Individuals with Autism: Evaluation for Evidence-Based Practices within a Best Evidence Synthesis Framework

ERIC Educational Resources Information Center

Reichow, Brian; Volkmar, Fred R.

2010-01-01

This paper presents a best evidence synthesis of interventions to increase social behavior for individuals with autism. Sixty-six studies published in peer-reviewed journals between 2001 and July 2008 with 513 participants were included. The results are presented by the age of the individual receiving intervention and by delivery agent of…

Bulk Synthesis of Monodisperse Ferrite Nanoparticles at Water-Organic Interfaces under Conventional and Microwave Hydrothermal Treatment and Their Surface Functionalization

EPA Science Inventory

Synthesis of monodisperse MFe2O4 (M=, Ni, Co, Mn) and γ-Fe2O3 nanoparticles at a water-toluene interface under conventional as well as microwave hydrothermal conditions using readily available nitrate or chloride salts and oleic acid as the dispersing agent is described. The ens...

Arabinosylthymine: inhibitor of splenic lymphocyte macromolecular synthesis in vitro.

PubMed Central

Barnett, J M; McGowan, J J; Gentry, G A

1979-01-01

The effect of arabinosylthymine on lymphocyte transformation was investigated. Arabinosylthymine was demonstrated not to be cytotoxic for hamster spleen lymphocytes but was found to inhibit the increase in deoxyribonucleic acid and protein synthesis usually observed as a result of mitogen stimulation. These findings suggest that, in addition to being a potent anti-herpesvirus inhibitor, arabinosylthymine is also an immunosuppressive agent. PMID:500206

Synthesis of Enantiomerically Pure Anthracyclinones

NASA Astrophysics Data System (ADS)

Achmatowicz, Osman; Szechner, Barbara

The anthracycline antibiotics are among the most important clinical drugs used in the treatment of human cancer. The search for new agents with improved therapeutic efficacy and reduced cardiotoxicity stimulated considerable efforts in the synthesis of new analogues. Since the biological activity of anthracyclines depends on their natural absolute configuration, various strategies for the synthesis of enantiomerically pure anthracyclinones (aglycones) have been developed. They comprise: resolution of racemic intermediate, incorporation of a chiral fragment derived from natural and non-natural chiral pools, asymmetric synthesis with the use of a chiral auxiliary or a chiral reagent, and enantioselective catalysis. Synthetic advances towards enantiopure anthracyclinones reported over the last 17 years are reviewed.

A novel metallogel based approach to synthesize (Mn, Cu) doped ZnS quantum dots and labeling of MCF-7 cancer cells.

PubMed

Bhowal, Soumya; Ghosh, Arijit; Chowdhuri, Srijita Paul; Mondal, Raju; Das, Benu Brata

2018-05-08

The present study aims to formulate a common synthetic strategy for preparing quantum dots (QDs) in a greener way by using combination of popular methods, viz. a colloidal method with suitable capping agent and low molecular weight gel based synthesis. Pyridine dicarboxylic acid (PDC) in presence of AlCl3 forms a stable metallogel, which serves as an excellent medium for selective ZnS QD synthesis. The aromatic pyridine moiety, well known for being a capping agent, indeed plays its part in the run up to QD synthesis. To the best of our knowledge, this is the first example of a metallogel based doped ZnS QD synthesis. Altering the doping material and its composition changes the properties of the QDs, but herein we also tried to establish how these changes affect the gel morphology and stability of both gel and QDs. We further demonstrate, by using live cell confocal microscopy, the delivery of QDs Cu ZnS and MnZnS nanomaterials in the nucleus and the cytoplasm of human breast cancer cells (MCF7), implicating the use of metallogel based QDs for bio-imaging and bio-labeling.

Carbon sequestration in forests as a national policy issue

Treesearch

Linda S. Heath; Linda A. Joyce

1997-01-01

The United States' 1993 Climate Change Action Plan called upon the forestry sector to sequester an additional 10 million metric tons/yr by the year 2000. Forests are currently sequestering carbon and may provide opportunities to mitigate fossil fuel emissions in the near-term until fossil fuel emissions can be reduced. Using the analysis of carbon budgets based on...

Forest carbon benefits, costs and leakage effects of carbon reserve scenarios in the United States

Treesearch

Prakash Nepal; Peter J. Ince; Kenneth E. Skog; Sun J. Chang

2013-01-01

This study evaluated the potential effectiveness of future carbon reserve scenarios, where U.S. forest landowners would hypothetically be paid to sequester carbon on their timberland and forego timber harvests for 100 years. Scenarios featured direct payments to landowners of $0 (baseline), $5, $10, or $15 per metric ton of additional forest carbon sequestered on the...

Aligning ecology and markets in the forest carbon cycle

Treesearch

Matthew D. Hurteau; Bruce A. Hungate; George W. Koch; Malcolm P. North; Gordon R Smith

2013-01-01

A forest carbon (C) offset is a quantifiable unit of C that is commonly developed at the local or regional project scale and is designed to counterbalance anthropogenic C emissions by sequestering C in trees. In capand- trade programs, forest offsets have market value if the sequestered C is additional (more than would have occurred in the absence of the project) and...

Elution of uranium and transition metals from amidoxime-based polymer adsorbents for sequestering uranium from seawater

DOE PAGES

Pan, Horng-Bin; Kuo, Li-Jung; Miyamoto, Naomi; ...

2015-11-30

High-surface-area amidoxime and carboxylic acid grafted polymer adsorbents developed at Oak Ridge National Laboratory were tested for sequestering uranium in a flowing seawater flume system at the PNNL-Marine Sciences Laboratory. FTIR spectra indicate that a KOH conditioning process is necessary to remove the proton from the carboxylic acid and make the sorbent effective for sequestering uranium from seawater. The alkaline conditioning process also converts the amidoxime groups to carboxylate groups in the adsorbent. Both Na 2CO 3 H 2O 2 and hydrochloric acid elution methods can remove ~95% of the uranium sequestered by the adsorbent after 42 days of exposuremore » in real seawater. The Na 2CO 3 H 2O 2 elution method is more selective for uranium than conventional acid elution. Iron and vanadium are the two major transition metals competing with uranium for adsorption to the amidoxime-based adsorbents in real seawater. Tiron (4,5-Dihydroxy-1,3-benzenedisulfonic acid disodium salt, 1 M) can remove iron from the adsorbent very effectively at pH around 7. The coordination between vanadium (V) and amidoxime is also discussed based on our 51V NMR data.« less

In-situ observation for growth of hierarchical metal-organic frameworks and their self-sequestering mechanism for gas storage

NASA Astrophysics Data System (ADS)

Hyo Park, Jung; Min Choi, Kyung; Joon Jeon, Hyung; Jung Choi, Yoon; Ku Kang, Jeung

2015-07-01

Although structures with the single functional constructions and micropores were demonstrated to capture many different molecules such as carbon dioxide, methane, and hydrogen with high capacities at low temperatures, their feeble interactions still limit practical applications at room temperature. Herein, we report in-situ growth observation of hierarchical pores in pomegranate metal-organic frameworks (pmg-MOFs) and their self-sequestering storage mechanism, not observed for pristine MOFs. Direct observation of hierarchical pores inside the pmg-MOF was evident by in-situ growth X-ray measurements while self-sequestering storage mechanism was revealed by in-situ gas sorption X-ray analysis and molecular dynamics simulations. The results show that meso/macropores are created at the early stage of crystal growth and then enclosed by micropore crystalline shells, where hierarchical pores are networking under self-sequestering mechanism to give enhanced gas storage. This pmg-MOF gives higher CO2 (39%) and CH4 (14%) storage capacity than pristine MOF at room temperature, in addition to fast kinetics with robust capacity retention during gas sorption cycles, thus giving the clue to control dynamic behaviors of gas adsorption.

Virtual odors to transmit emotions in virtual agents

NASA Astrophysics Data System (ADS)

Delgado-Mata, Carlos; Aylett, Ruth

2003-04-01

In this paper we describe an emotional-behvioral architecture. The emotional engine sits at a higher layer than the behavior system, and can alter behavior patterns, the engine is designed to simulate Emotionally-Intelligent Agents in a Virtual Environment, where each agent senses its own emotions, and other creature emotions through a virtual smell sensor; senses obstacles and other moving creatures in the environment and reacts to them. The architecture consists of an emotion engine, behavior synthesis system, a motor layer and a library of sensors.

Difluoromethylornithine in cancer: new advances.

PubMed

Alexiou, George A; Lianos, Georgios D; Ragos, Vassileios; Galani, Vasiliki; Kyritsis, Athanassios P

2017-04-01

Difluoromethylornithine (DFMO; eflornithine) is an irreversible suicide inhibitor of the enzyme ornithine decarboxylase which is involved in polyamine synthesis. Polyamines are important for cell survival, thus DFMO was studied as an anticancer agent and as a chemoprevention agent. DFMO exhibited mainly cytostatic activity and had single agent efficacy as well as activity in combination with other chemotherapeutic drugs for some cancers and leukemias. Herewith, we summarize the current knowledge of the anticancer and chemopreventive properties of DFMO and assess the status of clinical trials.

Titanium compounds as catalysts of higher alpha-olefin-based super-high-molecular polymers synthesis

NASA Astrophysics Data System (ADS)

Konovalov, K. B.; Kazaryan, M. A.; Manzhay, V. N.; Vetrova, O. V.

2016-01-01

The synthesis of polymers of 10 million or more molecular weight is a difficult task even in a chemical lab. Higher α-olefin-based polymer agents of such kind have found a narrow but quite important niche, the reduction of drag in the turbulent flow of hydrocarbon fluids such as oil and oil-products. In its turn, searching for a catalytic system capable to produce molecules of such a high length and to synthesize polymers of a low molecular-mass distribution is part of a global task of obtaining a high-quality product. In this paper we had observed a number of industrial catalysts with respect to their suitability for higher poly-α- olefins synthesis. A number samples representing copolymers of 1-hexene with 1-decene obtained on a previous generation catalyst, a microsphere titanium chloride catalytic agent had been compared to samples synthesized using a titanium-magnesium catalyst both in solution and in a polymer medium.

Cellulose-Silica Nanocomposites of High Reinforcing Content with Fungi Decay Resistance by One-Pot Synthesis

PubMed Central

Rodríguez-Robledo, M. Concepción; González-Lozano, M. Azucena; Ponce-Peña, Patricia; Quintana Owen, Patricia; Aguilar-González, Miguel Angel; Nieto-Castañeda, Georgina; López-Martínez, Rubén; Ramírez-Galicia, Guillermo

2018-01-01

Hybrid bionanocomposites based on cellulose matrix, with silica nanoparticles as reinforcers, were prepared by one-pot synthesis of cellulose surface modified by solvent exchange method to keep the biopolymer net void for hosting inorganic nanoparticles. Neither expensive inorganic-particle precursors nor crosslinker agents or catalysts were used for effective dispersion of reinforcer concentration up to 50 wt %. Scanning electron microscopy of the nanocomposites shows homogeneous dispersion of reinforcers in the surface modified cellulose matrix. The FTIR spectra demonstrated the cellulose features even at 50 weight percent content of silica nanoparticles. Such a high content of silica provides high thermal stability to composites, as seen by TGA-DSC. The fungi decay resistance to Trametes versicolor was measured by standard test showing good resistance even with no addition of antifungal agents. This one-pot synthesis of biobased hybrid materials represents an excellent way for industrial production of high performance materials, with a high content of inorganic nanoparticles, for a wide variety of applications. PMID:29642522

Cellulose-Silica Nanocomposites of High Reinforcing Content with Fungi Decay Resistance by One-Pot Synthesis.

PubMed

Rodríguez-Robledo, M Concepción; González-Lozano, M Azucena; Ponce-Peña, Patricia; Quintana Owen, Patricia; Aguilar-González, Miguel Angel; Nieto-Castañeda, Georgina; Bazán-Mora, Elva; López-Martínez, Rubén; Ramírez-Galicia, Guillermo; Poisot, Martha

2018-04-09

Hybrid bionanocomposites based on cellulose matrix, with silica nanoparticles as reinforcers, were prepared by one-pot synthesis of cellulose surface modified by solvent exchange method to keep the biopolymer net void for hosting inorganic nanoparticles. Neither expensive inorganic-particle precursors nor crosslinker agents or catalysts were used for effective dispersion of reinforcer concentration up to 50 wt %. Scanning electron microscopy of the nanocomposites shows homogeneous dispersion of reinforcers in the surface modified cellulose matrix. The FTIR spectra demonstrated the cellulose features even at 50 weight percent content of silica nanoparticles. Such a high content of silica provides high thermal stability to composites, as seen by TGA-DSC. The fungi decay resistance to Trametes versicolor was measured by standard test showing good resistance even with no addition of antifungal agents. This one-pot synthesis of biobased hybrid materials represents an excellent way for industrial production of high performance materials, with a high content of inorganic nanoparticles, for a wide variety of applications.

Hierarchical macro-mesoporous structures in the system TiO{sub 2}-Al{sub 2}O{sub 3}, obtained by hydrothermal synthesis using Tween-20 as a directing agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Benjume, M.L.; Espitia-Cabrera, M.I.; Contreras-Garcia, M.E., E-mail: eucontre@zeus.umich.mx

2009-12-15

Macro-mesoporous powders of titania, alumina, and mixed titania-20%alumina systems were obtained by hydrothermal synthesis employing surfactant Tween-20 as structural directing agent in order to promote the textural properties of titania. The effect of the alumina in the titania phase and on textural properties was analyzed. The obtained powders presented a macroporous channel structure that was characterized by X-ray diffractometry, scanning and transmission electron microscopy, N{sub 2} adsorption-desorption analysis, pore size distribution, Fourier transform infrared spectrometry, and thermogravimetric analysis. It was found that alumina content retarded the anatase phase crystallization and increased the Brunauer-Emmet-Teller surface area from 136 to 210 m{supmore » 2}/g. The powders calcined at 400 deg. C are thermally stable and possess an interconnected macro-mesoporous hierarchical structure; the results indicate that this synthesis can be employed to prepare mixed titania-alumina with good textural properties.« less

Red tea leaves infusion as a reducing and stabilizing agent in silver nanoparticles synthesis

NASA Astrophysics Data System (ADS)

Pluta, K.; Tryba, A. M.; Malina, D.; Sobczak-Kupiec, A.

2017-12-01

Due to the unique properties of silver nanoparticles there is growing interest in their applications. Current trends in nanotechnology are focused on developing a new technique to synthesize nanoparticles using biological methods associated with the use of plant extracts, fungi, bacteria or essential oils. These methods are a promising alternative to conventional approaches which can minimize the use of hazardous substances. The silver nanoparticles synthesis using red tea infusion as a reducing and stabilizing agent and their characteristics have been described. Total antioxidant capacity using DPPH radical and total content of phenolic compounds by Folin-Ciocalteau method were measured in tea infusion. Synthesis of silver nanoparticles was carried out using chemical reduction at various temperatures. Furthermore, the effect of tea infusion volume added to reaction mixture on nanoparticles’ properties was investigated. Finally, nanosilver suspensions were characterized by UV-vis spectrophotometer, dynamic light scattering (DLS) scanning electron microscope (SEM) and transmission electron microscope (TEM). Moreover, phytotoxicity of silver nanoparticles was determined using Phytotestkit microbiotest.

KHG26792 Inhibits Melanin Synthesis in Mel-Ab Cells and a Skin Equivalent Model

PubMed Central

Li, Hailan; Kim, Jandi; Hahn, Hoh-Gyu; Yun, Jun; Jeong, Hyo-Soon; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Min, Young Sil; Park, Kyoung-Chan

2014-01-01

The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy) methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyrosinase was not inhibited directly. KHG26792 activated extracellular signal-regulated kinase (ERK), whereas an ERK pathway inhibitor, PD98059, rescued KHG26792-induced hypopigmentation. These results suggest that KHG26792 decreases melanin production via ERK activation. Moreover, the hypopigmentary effects of KHG26792 were confirmed in a pigmented skin equivalent model using Cervi cornus Colla (deer antler glue), in which the color of the pigmented artificial skin became lighter after treatment with KHG26792. In summary, our findings suggest that KHG26792 is a novel skin whitening agent. PMID:24976765

KHG26792 Inhibits Melanin Synthesis in Mel-Ab Cells and a Skin Equivalent Model.

PubMed

Li, Hailan; Kim, Jandi; Hahn, Hoh-Gyu; Yun, Jun; Jeong, Hyo-Soon; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Min, Young Sil; Park, Kyoung-Chan; Kim, Dong-Seok

2014-06-01

The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy) methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyrosinase was not inhibited directly. KHG26792 activated extracellular signal-regulated kinase (ERK), whereas an ERK pathway inhibitor, PD98059, rescued KHG26792-induced hypopigmentation. These results suggest that KHG26792 decreases melanin production via ERK activation. Moreover, the hypopigmentary effects of KHG26792 were confirmed in a pigmented skin equivalent model using Cervi cornus Colla (deer antler glue), in which the color of the pigmented artificial skin became lighter after treatment with KHG26792. In summary, our findings suggest that KHG26792 is a novel skin whitening agent.

Silver nanoparticles with gelatin nanoshells: photochemical facile green synthesis and their antimicrobial activity

NASA Astrophysics Data System (ADS)

Pourjavadi, Ali; Soleyman, Rouhollah

2011-10-01

In the current study, a facile green synthesis of silver-gelatin core-shell nanostructures (spherical, spherical/cubic hybrid, and cubic, DLS diameter: 4.1-6.9 nm) is reported via the wet chemical synthesis procedure. Sunlight-UV as an available reducing agent cause mild reduction of silver ions into the silver nanoparticles (Ag-NPs). Gelatin protein, as an effective capping/shaping agent, was used in the reaction to self-assemble silver nanostructures. The formation of silver nanostructures and their self-assembly pattern was confirmed by SEM, AFM, and TEM techniques. Further investigations were carried out using zeta-potential, UV-Vis, FTIR, GPC, and TGA/DTG/DTA data. The prepared Ag-NPs showed proper and acceptable antimicrobial activity against three classes of microorganisms ( Escherichia coli Gram-negative bacteria, Staphylococcus aureus Gram-positive bacteria, and Candida albicans fungus). The antibacterial and antifungal Ag-NPs exhibit good stability in solution and can be considered as promising candidates for a wide range of biomedical applications.

Enhancement of the reduction efficiency of soluble starch for platinum nanoparticles synthesis.

PubMed

Tongsakul, Duangta; Wongravee, Kanet; Thammacharoen, Chuchaat; Ekgasit, Sanong

2012-08-01

In this work, the efficiency of soluble starch as a reducing and a stabilizing agent in the synthesis of platinum nanoparticles under acidic-alkaline treatment is systematically studied. The degraded intermediates with reducing potential (i.e., small molecules containing aldehyde and α-hydroxy ketone moieties) are concomitantly generated when the alkaline concentration is greater than 0.025 M. The in situ generated species could completely reduce platinum ions (20 mM) and sufficiently stabilize the obtained platinum nanoparticles (5 mM) of uniform particle size (2-4 nm). The reduction is efficient and rapid as a complete conversion is achieved within 5 min. In a stronger alkaline condition, the platinum nanoparticles tend to aggregate and form a bigger domain because extensive degradation generates small starch fragments with less stabilization efficiency. This observation suggests that starch is a promising green material which could be chemically treated and transformed to a powerful reducing agent and stabilizer for the synthesis of metal nanoparticles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Green chemistry for nanoparticle synthesis.

PubMed

Duan, Haohong; Wang, Dingsheng; Li, Yadong

2015-08-21

The application of the twelve principles of green chemistry in nanoparticle synthesis is a relatively new emerging issue concerning the sustainability. This field has received great attention in recent years due to its capability to design alternative, safer, energy efficient, and less toxic routes towards synthesis. These routes have been associated with the rational utilization of various substances in the nanoparticle preparations and synthetic methods, which have been broadly discussed in this tutorial review. This article is not meant to provide an exhaustive overview of green synthesis of nanoparticles, but to present several pivotal aspects of synthesis with environmental concerns, involving the selection and evaluation of nontoxic capping and reducing agents, the choice of innocuous solvents and the development of energy-efficient synthetic methods.

Synthesis of tin monosulfide (SnS) nanoparticles using surfactant free microemulsion (SFME) with the single microemulsion scheme

NASA Astrophysics Data System (ADS)

Tarkas, Hemant S.; Marathe, Deepak M.; Mahajan, Mrunal S.; Muntaser, Faisal; Patil, Mahendra B.; Tak, Swapnil R.; Sali, Jaydeep V.

2017-02-01

Synthesis of monomorphic, SnS nanoparticles without using a capping agent is a difficult task with chemical route of synthesis. This paper reports on synthesis of tin monosulfide (SnS) nanopartilces with dimension in the quantum-dot regime using surfactant free microemulsion with single microemulsion scheme. This has been achieved by reaction in microreactors in the CME (C: chlorobenzene, M: methanol and E: ethylene glycol) microemulsion system. This is an easy and controllable chemical route for synthesis of SnS nanoparticles. Nanoparticle diameter showed prominent dependence on microemulsion concentration and marginal dependence on microemulsion temperature in the temperature range studied. The SnS nanoparticles formed with this method form stable dispersion in Tolune.

A simple single-step approach towards synthesis of nanofluids containing cuboctahedral cuprous oxide particles using glucose reduction

NASA Astrophysics Data System (ADS)

Shenoy, U. Sandhya; Shetty, A. Nityananda

2018-03-01

Enhancement of thermal properties of conventional heat transfer fluids has become one of the important technical challenges. Since nanofluids offer a promising help in this regard, development of simpler and hassle free routes for their synthesis is of utmost importance. Synthesis of nanofluids using a hassle free route with greener chemicals has been reported. The single-step chemical approach reported here overcomes the drawbacks of the two-step procedures in the synthesis of nanofluids. The resulting Newtonian nanofluids prepared contained cuboctahedral particles of cuprous oxide and exhibited a thermal conductivity of 2.852 W·m-1·K-1. Polyvinylpyrrolidone (PVP) used during the synthesis acted as a stabilizing agent rendering the nanofluid a stability of 9 weeks.

A novel mode for transcription inhibition mediated by PNA-induced R-loops with a model in vitro system.

PubMed

D'Souza, Alicia D; Belotserkovskii, Boris P; Hanawalt, Philip C

2018-02-01

The selective inhibition of transcription of a chosen gene by an artificial agent has numerous applications. Usually, these agents are designed to bind a specific nucleotide sequence in the promoter or within the transcribed region of the chosen gene. However, since optimal binding sites might not exist within the gene, it is of interest to explore the possibility of transcription inhibition when the agent is designed to bind at other locations. One of these possibilities arises when an additional transcription initiation site (e.g. secondary promoter) is present upstream from the primary promoter of the target gene. In this case, transcription inhibition might be achieved by inducing the formation of an RNA-DNA hybrid (R-loop) upon transcription from the secondary promoter. The R-loop could extend into the region of the primary promoter, to interfere with promoter recognition by RNA polymerase and thereby inhibit transcription. As a sequence-specific R-loop-inducing agent, a peptide nucleic acid (PNA) could be designed to facilitate R-loop formation by sequestering the non-template DNA strand. To investigate this mode for transcription inhibition, we have employed a model system in which a PNA binding site is localized between the T3 and T7 phage RNA polymerase promoters, which respectively assume the roles of primary and secondary promoters. In accord with our model, we have demonstrated that with PNA-bound DNA substrates, transcription from the T7 promoter reduces transcription from the T3 promoter by 30-fold, while in the absence of PNA binding there is no significant effect of T7 transcription upon T3 transcription. Copyright © 2018 Elsevier B.V. All rights reserved.

Human APC sequesters beta-catenin even in the absence of GSK-3beta in a Drosophila model.

PubMed

Rao, P R; Makhijani, K; Shashidhara, L S

2008-04-10

There have been conflicting reports on the requirement of GSK-3beta-mediated phosphorylation of the tumor suppressor adenomatous polyposis coli (APC) vis-à-vis its ability to bind and degrade beta-catenin. Using a unique combination of loss of function for Shaggy/GSK-3beta and a gain of function for human APC in Drosophila, we show that misexpressed human APC (hAPC) can still sequester Armadillo/beta-catenin. In addition, human APC could suppress gain of Wnt/Wingless phenotypes associated with loss of Shaggy/GSK-3beta activity, suggesting that sequestered Armadillo/beta-catenin is non-functional. Based on these studies, we propose that binding per se of beta-catenin by APC does not require phosphorylation by GSK-3beta.

A preliminary assessment on the use of biochar as a soil additive for reducing soil-to-plant uptake of cesium isotopes in radioactively contaminated environments

DOE PAGES

Hamilton, Terry F.; Martinelli, Roger E.; Kehl, Steven R.; ...

2015-10-19

A series of K d tracer batch experiments were conducted in this paper to assess the absorptive-desorption properties of Biochar as a potential agent to selectively sequester labile soil Cs or otherwise help reduce the uptake of Cs isotopes into plants. A parallel experiment was conducted for strontium. Fine-grained fractionated Woodlands tree Biochar was found to have a relatively high affinity for Cs ions (K d > 100) relative to coral soil (K d < 10) collected from the Marshall Islands. The Biochar material also contains an abundance of K (and Mg). Finally, these findings support a hypothesis that themore » addition of Biochar as a soil amendment may provide a simple yet effective method for reducing soil-to-plant transfer of Cs isotopes in contaminated environments.« less

SEQUESTERING AGENTS FOR METAL IMMOBILIZATION APPLICATION TO THE DEVELOPMENT OF ACTIVE CAPS IN FRESH AND SALT WATER SEDIMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knox, A; Michael Paller, M

2006-11-17

This research evaluated the removal of inorganic contaminants by a variety of amendments and mixtures of amendments in fresh and salt water. A series of removal and retention batch experiments was conducted to identify the best treatment for metal removal. Metal removal by the amendments was evaluated by calculating the partition coefficient and percent removal. Retention of metals by the amendments was evaluated in retention (desorption) studies in which residue from the removal studies was extracted with 1 M MgCl{sub 2} solution. The results indicated that phosphate amendments, some organoclays (e.g., OCB-750), and the biopolymer, chitosan, are very effective inmore » removal and retention of metals in both fresh and salt water. These amendments are being evaluated further as components in the development of active caps for sediment remediation.« less

A review of the mechanism of injury and treatment approaches for illness resulting from exposure to water-damaged buildings, mold, and mycotoxins.

PubMed

Hope, Janette

2013-01-01

Physicians are increasingly being asked to diagnose and treat people made ill by exposure to water-damaged environments, mold, and mycotoxins. In addition to avoidance of further exposure to these environments and to items contaminated by these environments, a number of approaches have been used to help persons affected by exposure to restore their health. Illness results from a combination of factors present in water-damaged indoor environments including, mold spores and hyphal fragments, mycotoxins, bacteria, bacterial endotoxins, and cell wall components as well as other factors. Mechanisms of illness include inflammation, oxidative stress, toxicity, infection, allergy, and irritant effects of exposure. This paper reviews the scientific literature as it relates to commonly used treatments such as glutathione, antioxidants, antifungals, and sequestering agents such as cholestyramine, charcoal, clay and chlorella, antioxidants, probiotics, and induced sweating.

A Review of the Mechanism of Injury and Treatment Approaches for Illness Resulting from Exposure to Water-Damaged Buildings, Mold, and Mycotoxins

PubMed Central

2013-01-01

Physicians are increasingly being asked to diagnose and treat people made ill by exposure to water-damaged environments, mold, and mycotoxins. In addition to avoidance of further exposure to these environments and to items contaminated by these environments, a number of approaches have been used to help persons affected by exposure to restore their health. Illness results from a combination of factors present in water-damaged indoor environments including, mold spores and hyphal fragments, mycotoxins, bacteria, bacterial endotoxins, and cell wall components as well as other factors. Mechanisms of illness include inflammation, oxidative stress, toxicity, infection, allergy, and irritant effects of exposure. This paper reviews the scientific literature as it relates to commonly used treatments such as glutathione, antioxidants, antifungals, and sequestering agents such as Cholestyramine, charcoal, clay and chlorella, antioxidants, probiotics, and induced sweating. PMID:23710148

Current technologies for biological treatment of textile wastewater--a review.

PubMed

Sarayu, K; Sandhya, S

2012-06-01

The release of colored wastewater represents a serious environmental problem and public health concern. Color removal from textile wastewater has become a big challenge over the last decades, and up to now, there is no single and economically attractive treatment method that can effectively decolorize the wastewater. Effluents from textile manufacturing, dyeing, and finishing processes contain high concentrations of biologically difficult-to-degrade or even inert auxiliaries, chemicals like acids, waxes, fats, salts, binders, thickeners, urea, surfactants, reducing agents, etc. The various chemicals such as biocides and stain repellents used for brightening, sequestering, anticreasing, sizing, softening, and wetting of the yarn or fabric are also present in wastewater. Therefore, the textile wastewater needs environmental friendly, effective treatment process. This paper provides a critical review on the current technology available for decolorization and degradation of textile wastewater and also suggests effective and economically attractive alternatives.

Smart swelling biopolymer microparticles by a microfluidic approach: synthesis, in situ encapsulation and controlled release.

PubMed

Fang, Aiping; Cathala, Bernard

2011-01-01

This paper reports a microfluidic synthesis of biopolymer microparticles aiming at smart swelling. Monodisperse aqueous emulsion droplets comprising biopolymer and its cross-linking agent were formed in mineral oil and solidified in the winding microfluidic channels by in situ chaotic mixing, which resulted in internal chemical gelation for hydrogels. The achievement of pectin microparticles from in situ mixing pectin with its cross-linking agent, calcium ions, successfully demonstrates the reliability of this microfluidic synthesis approach. In order to achieve hydrogels with smart swelling, the following parameters and their impacts on the swelling behaviour, stability and morphology of microparticles were investigated: (1) the type of biopolymers (alginate or mixture of alginate and carboxymethylcellulose, A-CMC); (2) rapid mixing; (3) concentration and type of cross-linking agent. Superabsorbent microparticles were obtained from A-CMC mixture by using ferric chloride as an additional external cross-linking agent. The in situ encapsulation of a model protein, bovine serum albumin (BSA), was also carried out. As a potential protein drug-delivery system, the BSA release behaviours of the biopolymer particles were studied in simulated gastric and intestinal fluids. Compared with alginate and A-CMC microparticles cross-linked with calcium ions, A-CMC microparticles cross-linked with both calcium and ferric ions demonstrate a significantly delayed release. The controllable release profile, the facile encapsulation as well as their biocompatibility, biodegradability, mucoadhesiveness render this microfluidic approach promising in achieving biopolymer microparticles as protein drug carrier for site-specific release. Copyright © 2010 Elsevier B.V. All rights reserved.

Nucleic Acid-Based Nanoconstructs

Cancer.gov

Focuses on the design, synthesis, characterization, and development of spherical nucleic acid constructs as effective nanotherapeutic, single-entity agents for the treatment of glioblastoma multiforme and prostate cancers.

Bio-inspired green synthesis of Fe3O4 magnetic nanoparticles using watermelon rinds and their catalytic activity

NASA Astrophysics Data System (ADS)

Prasad, Ch.; Gangadhara, S.; Venkateswarlu, P.

2016-08-01

Novel and bio-inspired magnetic nanoparticles were synthesized using watermelon rinds (WR) which are nontoxic and biodegradable. Watermelon rind extract was used as a solvent and capping and reducing agent in the synthesis. The Fe3o4 MNPs were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer techniques (VSM). XRD studies revealed a high degree of crystalline and monophasic Fe nanoparticles of face-centered cubic stricture. FTIR analysis proved that particles are reduced and stabilized in solution by the capping agent that is likely to be proteins secreted by the biomass. The present process in an excellent candidate for the synthesis of iron nanoparticles that is simple, easy to execute, pollutant free and inexpensive. A practical and convenient method for the synthesis of highly stable and small-sized iron nanoparticles with a narrow distribution from 2 to 20 nm is reported. Also, the MNPs present in higher saturation magnetization (Ms) of 14.2 emu/g demonstrate tremendous magnetic response behavior. However, the synthesized iron nanoparticles were used as a catalyst for the preparation of biologically interesting 2-oxo-1,2,3,4-tetrahydropyrimidine derivatives in high yields. These results exhibited that the synthesized Fe3O4 MNPs could be used as a catalyst in organic synthesis.

Synthesis of silver nanoparticles stabilized with C-phycocyanin and for fluorimetric detection of copper ions

NASA Astrophysics Data System (ADS)

Wei, Nana; Hou, Yanhua; Lu, Zongbao; Yu, Huatong; Wang, Quanfu

2018-01-01

In this study, C-phycocyanin as protective agent, AgNO3 as raw material and NaBH4 as reducing agent synthesized C-phycocyanin-Ag nanoparticles (PC-AgNPs). The synthesis conditions of PC-AgNPs were determined by optimization. The maximum UV absorption peak of PC-AgNPs at 400 nm. The fluorescence excitation wavelength was 580 nm and the emission wavelength was 625 nm. PC-AgNPs was spherical in transmission electron microscope and the particles sizes were about 10-25 nm. In addition, fluorescence quenching was observed after adding copper ions to PC-AgNPs, which indicated that PC-AgNPs has potential applications in the detection of copper ions in diverse water environment.

Tricholin, a new antifungal agent from Trichoderma viride, and its action in biological control of Rhizoctonia solani.

PubMed

Lin, A; Lee, T M; Rern, J C

1994-07-01

Tricholin, a ribosome-inactivating protein isolated from the culture broth of Trichoderma viride, has been shown to exert fungicidal effects on Rhizoctonia solani through a multi-hit kinetic interaction. Tricholin causes a parallel cessation of growth, uptake of amino acids, and protein biosynthesis. The in vivo mode of action of tricholin on protein synthesis and cell growth appears to be attributed to the diminishing of the polysome formation in R. solani through damage to large ribosomal subunits. These results concur with previous data and prove that tricholin is an effective inhibitor of protein synthesis. The efficacy of tricholin as an antibiotic agent was estimated to have a duration of approximately 42 hours.

The synthesis and dynamics research of new curing agent for epoxy resin

NASA Astrophysics Data System (ADS)

Peng, Yongli; Huang, Hengyu; Sun, Yong

2017-05-01

Two-step synthesis of trimellitic anhydride trimellitic anhydride n - butyl ester (TMNB) was introduced which could be used as an epoxy resin curing agent. The kinetics of the curing reaction was analyzed by N-order model and autocatalytic model. The curing kinetics parameters, the results show that the curing activation energy (Ea) of this system was 35.79kJ / mol. The kinetic equation of curing was d/a d t =2.1061 ×104e x p (-35.79/R T ) α0.5163(l-α ) 0.366 . Combined with β-1 / T extrapolation and experimental adjustment to obtain the resin system curing process: 75°C for 1h, 140°C for 3h, 160°C for 2h.

Design, synthesis and evaluation of a new Mn - Contrast agent for MR imaging of myocardium based on the DTPA-phenylpentadecanoic acid complex

NASA Astrophysics Data System (ADS)

Belyanin, Maxim L.; Stepanova, Elena V.; Valiev, Rashid R.; Filimonov, Victor D.; Usov, Vladimir Y.; Borodin, Oleg Y.; Ågren, Hans

2016-11-01

In the present paper we describe the first synthesis and evaluation of a novel Mn (II) complex (DTPA-PPDA Mn (II)) which contains a C-15 fatty acid moiety that has high affinity to the heart muscle. The complexation energy of DTPA-PPDA Mn (II) evaluated by quantum chemistry methodology indicates that it essentially exceeds the corresponding value for the known DTPA Mn (II) complex. Molecular docking revealed that the affinity of the designed complex to the heart-type transport protein H-FABP well exceeds that of lauric acid. Phantom experiments in low-field MRI the designed contrast agent provides MR imaging comparable to gadopentetic acid.

Synthesis of gold nanoflowers using deep eutectic solvent with high surface enhanced Raman scattering properties

NASA Astrophysics Data System (ADS)

Aghakhani Mahyari, Farzaneh; Tohidi, Maryam; Safavi, Afsaneh

2016-09-01

A facile, seed-less and one-pot method was developed for synthesis of gold nanoflowers with multiple tips through reduction of HAuCl4 with deep eutectic solvent at room temperature. This solvent is eco-friendly, low-cost, non-toxic and biodegradable and can act as both reducing and shape-controlling agent. In this protocol, highly branched and stable gold nanoflowers were obtained without using any capping agent. The obtained products were characterized by different techniques including, field emission scanning electron microscopy, transmission electron microscopy, x-ray diffraction and UV-vis spectroscopy. The as-prepared gold nanoflowers exhibit efficient surface-enhanced Raman scattering (SERS) properties which can be used as excellent substrates for SERS.

Anti-AIDS agents 81. Design, synthesis, and structure-activity relationship study of betulinic acid and moronic acid derivatives as potent HIV maturation inhibitors.

PubMed

Qian, Keduo; Kuo, Reen-Yun; Chen, Chin-Ho; Huang, Li; Morris-Natschke, Susan L; Lee, Kuo-Hsiung

2010-04-22

In our continuing study of triterpene derivatives as potent anti-HIV agents, different C-3 conformationally restricted betulinic acid (BA, 1) derivatives were designed and synthesized in order to explore the conformational space of the C-3 pharmacophore. 3-O-Monomethylsuccinyl-betulinic acid (MSB) analogues were also designed to better understand the contribution of the C-3' dimethyl group of bevirimat (2), the first-in-class HIV maturation inhibitor, which is currently in phase IIb clinical trials. In addition, another triterpene skeleton, moronic acid (MA, 3), was also employed to study the influence of the backbone and the C-3 modification toward the anti-HIV activity of this compound class. This study enabled us to better understand the structure-activity relationships (SAR) of triterpene-derived anti-HIV agents and led to the design and synthesis of compound 12 (EC(50): 0.0006 microM), which displayed slightly better activity than 2 as a HIV-1 maturation inhibitor.

Synthesis, Characterization and Biological Evaluation of Some Quinoxaline Derivatives: A Promising and Potent New Class of Antitumor and Antimicrobial Agents.

PubMed

Al-Marhabi, Aisha R; Abbas, Hebat-Allah S; Ammar, Yousry A

2015-11-03

In continuation of our endeavor towards the development of potent and effective anticancer and antimicrobial agents; the present work deals with the synthesis of some novel tetrazolo[1,5-a]quinoxalines, N-pyrazoloquinoxalines, the corresponding Schiff bases, 1,2,4-triazinoquinoxalines and 1,2,4-triazoloquinoxalines. These compounds were synthesized via the reaction of the key intermediate hydrazinoquinoxalines with various reagents and evaluated for anticancer and antimicrobial activity. The results indicated that tetrazolo[1,5-a]quinoxaline derivatives showed the best result, with the highest inhibitory effects towards the three tested tumor cell lines, which were higher than that of the reference doxorubicin and these compounds were non-cytotoxic to normal cells (IC50 values > 100 μg/mL). Also, most of synthesized compounds exhibited the highest degrees of inhibition against the tested strains of Gram positive and negative bacteria, so tetrazolo[1,5-a]quinoxaline derivatives show dual activity as anticancer and antimicrobial agents.

One-pot synthesis of MWW zeolite nanosheets using a rationally designed organic structure-directing agent

DOE PAGES

Luo, Helen Y.; Michaelis, Vladimir K.; Hodges, Sydney; ...

2015-07-22

A new material MIT-1 comprised of delaminated MWW zeolite nanosheets is synthesized in one-pot using a rationally designed organic structure-directing agent (OSDA). The OSDA is comprised of a hydrophilic head segment that resembles the OSDA used to synthesize the zeolite precursor MCM22(P), a hydrophobic tail segment that resembles the swelling agent used to swell MCM22(P), and a di-quaternary ammonium linker that connects both segments. MIT-1 features high crystallinity and surface areas exceeding 500 m 2g -1, and can be synthesized over a wide synthesis window that includes Si/Al ratios ranging from 13 to 67. Characterization data reveal high mesoporosity andmore » acid strength with no detectable amorphous silica phases. In conclusion, compared to MCM-22 and MCM-56, MIT-1 shows a three-fold increase in catalytic activity for the Friedel-Crafts alkylation of benzene with benzyl alcohol.« less

Serotonin, atherosclerosis, and collateral vessel spasm

NASA Technical Reports Server (NTRS)

Hollenberg, N.

1988-01-01

Studies on animal models demonstrate that platelet products contribute to vascular spasm in ischemic syndromes and that this is reversible with administration of ketanserin and thromboxane synthesis inhibitors. Laboratory animals (dogs, rabbits, and rats) that had femoral artery ligations exhibited supersensitivity to serotonin within days in their collateral blood vessels. This supersensitivity lasted at least 6 months. The response to serotonin was reversed by ketanserin, but not by 5HT-1 antagonists. Supersensitivity does not extend to norepinephrine, and alpha blockers do not influence the response to serotonin. It appears that platelet activation by endothelial injury contributes to ischemia through blood vessel occlusion and vascular spasm. When platelet activation occurs in vivo, blood vessel occlusion and vascular spasm are reversible in part by using ketanserin or agents that block thromboxane synthesis or its action. Combining both classes of agents reverses spasm completely. These findings support existing evidence that platelet products contribute to vascular disease, and provide an approach to improved management with currently available pharmacologic agents.

Axinellamines as Broad-Spectrum Antibacterial Agents: Scalable Synthesis and Biology

PubMed Central

2015-01-01

Antibiotic-resistant bacteria present an ongoing challenge to both chemists and biologists as they seek novel compounds and modes of action to out-maneuver continually evolving resistance pathways, especially against Gram-negative strains. The dimeric pyrrole–imidazole alkaloids represent a unique marine natural product class with diverse primary biological activity and chemical architecture. This full account traces the strategy used to develop a second-generation route to key spirocycle 9, culminating in a practical synthesis of the axinellamines and enabling their discovery as broad-spectrum antibacterial agents, with promising activity against both Gram-positive and Gram-negative bacteria. While their detailed mode of antibacterial action remains unclear, the axinellamines appear to cause secondary membrane destabilization and impart an aberrant cellular morphology consistent with the inhibition of normal septum formation. This study serves as a rare example of a natural product initially reported to be devoid of biological activity surfacing as an active antibacterial agent with an intriguing mode of action. PMID:25328977

Aryl sulfonate based anticancer alkylating agents.

PubMed

Sheikh, Hamdullah Khadim; Arshad, Tanzila; Kanwal, Ghazala

2018-05-01

This research work revolves around synthesis of antineoplastic alkylating sulfonate esters with dual alkylating sites for crosslinking of the DNA strands. These molecules were evaluated as potential antineoplastic cross linking alkylating agents by reaction with the nucleoside of Guanine DNA nucleobase at both ends of the synthesized molecule. Synthesis of the alkylating molecules and the crosslinking with the guanosine nucleoside was monitored by MALDITOF mass spectroscopy. The synthesized molecule's crosslinking or adduct forming rate with the nucleoside was compared with that of 1,4 butane disulfonate (busulfan), in form of time taken for the appearance of [M+H] + . It was found that aryl sulfonate leaving group was causing higher rate of nucleophilic attack by the Lewis basic site of the nucleobase. Furthermore, the rate was also found to be a function of electron withdrawing or donating nature of the substituent on the aryl ring. Compound with strong electron withdrawing substituent on the para position of the ring reacted fastest. Hence, new alkylating agents were synthesized with optimized or desired reactivity.

Synthesis and SAR studies of potent imidazopyridine anticoccidial agents.

PubMed

Liang, Gui-Bai; Qian, Xiaoxia; Feng, Dennis; Fisher, Michael; Brown, Christine M; Gurnett, Anne; Leavitt, Penny Sue; Liberator, Paul A; Misura, Andrew S; Tamas, Tamas; Schmatz, Dennis M; Wyvratt, Matthew; Biftu, Tesfaye

2007-07-01

Diaryl imidazo[1,2-a]pyridine derivatives, such as 6a and 7i, have been synthesized and found to be potent inhibitors of parasite PKG activity. The most potent compounds are the 7-isopropylaminomethyl analog 6a and 2-isopropylamino analog 7i. These compounds are also fully active in in vivo assay as anticoccidial agents at 25 ppm in feed.

One-step synthesis of mesoporous pentasil zeolite with single-unit-cell lamellar structural features

DOEpatents

Tsapstsis, Michael; Zhang, Xueyi

2015-11-17

A method for making a pentasil zeolite material includes forming an aqueous solution that includes a structure directing agent and a silica precursor; and heating the solution at a sufficient temperature and for sufficient time to form a pentasil zeolite material from the silica precursor, wherein the structure directing agent includes a quaternary phosphonium ion.

In vivo photoacoustic tumor tomography using a quinoline-annulated porphyrin as NIR molecular contrast agent.

PubMed

Luciano, Michael; Erfanzadeh, Mohsen; Zhou, Feifei; Zhu, Hua; Bornhütter, Tobias; Röder, Beate; Zhu, Quing; Brückner, Christian

2017-01-25

The synthesis and photophysical properties of a tetra-PEG-modified and freely water-soluble quinoline-annulated porphyrin are described. We previously demonstrated the ability of quinoline-annulated porphyrins to act as an in vitro NIR photoacoustic imaging (PAI) contrast agent. The solubility of the quinoline-annulated porphyrin derivative in serum now allowed the assessment of the efficacy of the PEGylated derivative as an in vivo NIR contrast agent for the PAI of an implanted tumor in a mouse model. A multi-fold contrast enhancement when compared to the benchmark dye ICG could be shown, a finding that could be traced to its photophysical properties (short triplet lifetimes, low fluorescence and singlet oxygen sensitization quantum yields). A NIR excitation wavelength of 790 nm could be used, fully taking advantage of the optical window of tissue. Rapid renal clearance of the dye was observed. Its straight-forward synthesis, optical properties with the possibility for further optical fine-tuning, nontoxicity, favorable elimination rates, and contrast enhancement make this a promising PAI contrast agent. The ability to conjugate the PAI chromophore with a fluorescent tag using a facile and general conjugation strategy was also demonstrated.

Combinatorial synthesis and in vitro evaluation of a biaryl hydroxyketone library as antivirulence agents against MRSA.

PubMed

Yu, Guanping; Kuo, David; Shoham, Menachem; Viswanathan, Rajesh

2014-02-10

Antibiotic resistance coupled with decreased development of new antibiotics necessitates the search for novel antibacterial agents. Antivirulence agents offer an alternative to conventional antibiotics. In this work, we report on a family of small-molecule antivirulence agents against methicillin-resistant Staphylococcus aureus (MRSA), the most widespread bacterial pathogen. Structure-activity relationship studies led to the development of a concise synthesis of a 148-member biarylhydroxyketone library. An acylation bond-forming process afforded resorcinols (1) and aryloxy acetonitriles (2) as synthons. A Lewis-acid-activated Friedel-Crafts' acylation step involving a nitrile functionality of 2 by ZnCl2, followed by nucleophilic attack by 1 was executed to obtain biaryl hydroxyketones in excellent yields. A large number of products crystallized. This strategy affords a range of biarylhydroxyketones in a single step. This is the first collective synthetic study documenting access to this class of compounds through a single synthetic operation. In vitro efficacy of compounds in this library was evaluated by a rabbit erythrocyte hemolysis assay. The most efficacious compound, 4f-12, inhibits hemolysis by 98.1 ± 0.1% compared to control in the absence of the compound.

Naive CD8 T-Cells Initiate Spontaneous Autoimmunity to a Sequestered Model Antigen of the Central Nervous System

ERIC Educational Resources Information Center

Na, Shin-Young; Cao, Yi; Toben, Catherine; Nitschke, Lars; Stadelmann, Christine; Gold, Ralf; Schimpl, Anneliese; Hunig, Thomas

2008-01-01

In multiple sclerosis, CD8 T-cells are thought play a key pathogenetic role, but mechanistic evidence from rodent models is limited. Here, we have tested the encephalitogenic potential of CD8 T-cells specific for the model antigen ovalbumin (OVA) sequestered in oligodendrocytes as a cytosolic molecule. We show that in these "ODC-OVA" mice, the…

Economic Analysis of Planting Forests on Rice Lands in Texas: Sequestering Carbon and Avoiding Methane Production

NASA Astrophysics Data System (ADS)

Kronrad, G. D.; Huang, C.

2005-12-01

Global climate change is predicted due to increases in greenhouse gasses (i.e. CO2, CH4, CFCs, N2O, O3) in the atmosphere caused by human activities. The atmospheric concentration of methane (CH4), which absorbs and retains heat 21 times more effectively than CO2, has increased. Anaerobic bacterial activity in rice paddies constitutes one of major emission sources of CH4. The rice fields of Texas, for example, accounted for an annual CH4 emission of between 1.1 and 1.6 million tons of CO2 equivalent between 1990 and 2000. Converting marginal rice fields to forests plantations will remove CO2 from the atmosphere, sequester carbon in the forests and prevent the production of CH4. Therefore, carbon credits can be claimed for the carbon sequestered and the avoidance of CH4 production. Analyses were conducted to calculate the amount of carbon sequestered and methane avoided, and the profitability, measured in net present worth (NPW), of managing loblolly pine plantation for 1) timber production only, 2) the dual products of timber products and carbon credits in forests planted on marginal agricultural and unused pastureland and 3) the dual products of timber and carbon storage in forests planted on marginal rice lands. Calculations were performed using three discount rates, three site qualities and five prices for carbon credits. The results indicate that on average quality land, using a discount rate of 8 percent, forests planted on marginal agricultural and unused pastureland earn a NPW of 346 per acre from timber production only; a NPW of 438 per acre from timber and carbon credits (54.4 tons of carbon sequestered), assuming carbon is worth 10 per ton, during one rotation (32 years). The profitability of forest management increases due to the inclusion of carbon credits. The profitability of planting forests on marginal rice fields is even higher, earning a NPW of 566 per acre from timber and carbon credits (54.4 tons of C sequestered and 33.3 tons of C emission avoided).

Saccharin Derivative Synthesis via [1,3] Thermal Sigmatropic Rearrangement: A Multistep Organic Chemistry Experiment for Undergraduate Students

ERIC Educational Resources Information Center

Fonseca, Custódia S. C.

2016-01-01

Saccharin (1,2-benzisothiazole-3-one 1,1-dioxide) is an artificial sweetener used in the food industry. It is a cheap and easily available organic compound that may be used in organic chemistry laboratory classes for the synthesis of related heterocyclic compounds and as a derivatizing agent. In this work, saccharin is used as a starting material…

Synthesis and Properties of Chelating N-Heterocyclic Carbene Rhodium(I) Complexes: Synthetic Experiments in Current Organometallic Chemistry

ERIC Educational Resources Information Center

Mata, Jose A.; Poyatos, Macarena; Mas-Marza, Elena

2011-01-01

The preparation and characterization of two air-stable Rh(I) complexes bearing a chelating N-heterocyclic carbene (NHC) ligand is described. The synthesis involves the preparation of a Ag(I)-NHC complex and its use as carbene transfer agent to a Rh(I) precursor. The so obtained complex can be further reacted with carbon monoxide to give the…

Ferrocene-pyrimidine conjugates: Synthesis, electrochemistry, physicochemical properties and antiplasmodial activities.

PubMed

Chopra, Rakesh; de Kock, Carmen; Smith, Peter; Chibale, Kelly; Singh, Kamaljit

2015-07-15

The promise of hybrid antimalarial agents and the precedence set by the antimalarial drug ferroquine prompted us to design ferrocene-pyrimidine conjugates. Herein, we report the synthesis, electrochemistry and anti-plasmodial evaluation of ferrocenyl-pyrimidine conjugates against chloroquine susceptible NF54 strain of the malaria parasite Plasmodium falciparum. Also their physicochemical properties have been studied. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A defect in homologous recombination leads to increased translesion synthesis in E. coli

PubMed Central

Naiman, Karel; Pagès, Vincent; Fuchs, Robert P.

2016-01-01

DNA damage tolerance pathways allow cells to duplicate their genomes despite the presence of replication blocking lesions. Cells possess two major tolerance strategies, namely translesion synthesis (TLS) and homology directed gap repair (HDGR). TLS pathways involve specialized DNA polymerases that are able to synthesize past DNA lesions with an intrinsic risk of causing point mutations. In contrast, HDGR pathways are essentially error-free as they rely on the recovery of missing information from the sister chromatid by RecA-mediated homologous recombination. We have investigated the genetic control of pathway choice between TLS and HDGR in vivo in Escherichia coli. In a strain with wild type RecA activity, the extent of TLS across replication blocking lesions is generally low while HDGR is used extensively. Interestingly, recA alleles that are partially impaired in D-loop formation confer a decrease in HDGR and a concomitant increase in TLS. Thus, partial defect of RecA's capacity to invade the homologous sister chromatid increases the lifetime of the ssDNA.RecA filament, i.e. the ‘SOS signal’. This increase favors TLS by increasing both the TLS polymerase concentration and the lifetime of the TLS substrate, before it becomes sequestered by homologous recombination. In conclusion, the pathway choice between error-prone TLS and error-free HDGR is controlled by the efficiency of homologous recombination. PMID:27257075

Paramyxovirus activation and inhibition of innate immune responses.

PubMed

Parks, Griffith D; Alexander-Miller, Martha A

2013-12-13

Paramyxoviruses represent a remarkably diverse family of enveloped nonsegmented negative-strand RNA viruses, some of which are the most ubiquitous disease-causing viruses of humans and animals. This review focuses on paramyxovirus activation of innate immune pathways, the mechanisms by which these RNA viruses counteract these pathways, and the innate response to paramyxovirus infection of dendritic cells (DC). Paramyxoviruses are potent activators of extracellular complement pathways, a first line of defense that viruses must face during natural infections. We discuss mechanisms by which these viruses activate and combat complement to delay neutralization. Once cells are infected, virus replication drives type I interferon (IFN) synthesis that has the potential to induce a large number of antiviral genes. Here we describe four approaches by which paramyxoviruses limit IFN induction: by limiting synthesis of IFN-inducing aberrant viral RNAs, through targeted inhibition of RNA sensors, by providing viral decoy substrates for cellular kinase complexes, and through direct blocking of the IFN promoter. In addition, paramyxoviruses have evolved diverse mechanisms to disrupt IFN signaling pathways. We describe three general mechanisms, including targeted proteolysis of signaling factors, sequestering cellular factors, and upregulation of cellular inhibitors. DC are exceptional cells with the capacity to generate adaptive immunity through the coupling of innate immune signals and T cell activation. We discuss the importance of innate responses in DC following paramyxovirus infection and their consequences for the ability to mount and maintain antiviral T cells. © 2013.

Paramyxovirus Activation and Inhibition of Innate Immune Responses

PubMed Central

Parks, Griffith D.; Alexander-Miller, Martha A.

2014-01-01

Paramyxoviruses represent a remarkably diverse family of enveloped nonsegmented negative-strand RNA viruses, some of which are the most ubiquitous disease-causing viruses of humans and animals. This review focuses on paramyxovirus activation of innate immune pathways, the mechanisms by which these RNA viruses counteract these pathways, and the innate response to paramyxovirus infection of dendritic cells (DC). Paramyxoviruses are potent activators of extracellular complement pathways, a first line of defense that viruses must face during natural infections. We discuss mechanisms by which these viruses activate and combat complement to delay neutralization. Once cells are infected, virus replication drives type I interferon (IFN) synthesis that has the potential to induce a large number of antiviral genes. Here we describe four approaches by which paramyxoviruses limit IFN induction: by limiting synthesis of IFN-inducing aberrant viral RNAs, through targeted inhibition of RNA sensors, by providing viral decoy substrates for cellular kinase complexes, and through direct blocking of the IFN promoter. In addition, paramyxoviruses have evolved diverse mechanisms to disrupt IFN signaling pathways. We describe three general mechanisms, including targeted proteolysis of signaling factors, sequestering cellular factors, and upregulation of cellular inhibitors. DC are exceptional cells with the capacity to generate adaptive immunity through the coupling of innate immune signals and T cell activation. We discuss the importance of innate responses in DC following paramyxovirus infection and their consequences for the ability to mount and maintain antiviral T cells. PMID:24056173

Multiple exciton generation in cluster-free alloy Cd(x)Hg(1-x)Te colloidal quantum dots synthesized in water.

PubMed

Kershaw, Stephen V; Kalytchuk, Sergii; Zhovtiuk, Olga; Shen, Qing; Oshima, Takuya; Yindeesuk, Witoon; Toyoda, Taro; Rogach, Andrey L

2014-12-21

A number of different composition CdxHg1-xTe alloy quantum dots have been synthesized using a modified aqueous synthesis and ion exchange method. The benefits of good stoichiometric control and high emission quantum yield were retained whilst also ensuring that the tendency to form gel-like clusters and adsorb excess cations in the stabilizing ligand shells was mitigated using a sequestering method to remove excess ionic material during and after the synthesis. This was highly desirable for ultrafast carrier dynamics measurements, avoiding strong photocharging effects which may mask fundamental carrier signals. Transient grating measurements revealed a composition dependent carrier multiplication process which competes with phonon mediated carrier cooling to deplete the initial hot carrier population. The interplay between these two mechanisms is strongly dependent on the electron effective mass which in these alloys has a marked composition dependence and may be considerably lower than the hole effective mass. For a composition x = 0.52 we measured a maximum carrier multiplication quantum yield of 199 ± 19% with pump photon energy 3 times the bandgap energy, Eg, whilst the threshold energy is calculated to be just 2.15Eg. There is some evidence to suggest an impact ionization process analogous to the inverse Auger S mechanism seen in bulk CdxHg1-xTe.

The interferon response circuit in antiviral host defense.

PubMed

Haller, O; Weber, F

2009-01-01

Viruses have learned to multiply in the face of a powerful innate and adaptive immune response of the host. They have evolved multiple strategies to evade the interferon (IFN) system which would otherwise limit virus growth at an early stage of infection. IFNs induce the synthesis of a range of antiviral proteins which serve as cell-autonomous intrinsic restriction factors. For example, the dynamin-like MxA GTPase inhibits the multiplication of influenza and bunyaviruses (such as La Crosse virus, Hantaan virus, Rift Valley Fever virus, and Crimean-Congo hemorrhagic fever virus) by binding and sequestering the nucleocapsid protein into large perinuclear complexes. To overcome such intracellular restrictions, virulent viruses either inhibit IFN synthesis, bind and inactivate secreted IFN molecules, block IFN-activated signaling, or disturb the action of IFN-induced antiviral proteins. Many viruses produce specialized proteins to disarm the danger signal or express virulence genes that target members of the IFN regulatory factor family (IRFs) or components of the JAK-STAT signaling pathway. An alternative evasion strategy is based on extreme viral replication speed which out-competes the IFN response. The identification of viral proteins with IFN antagonistic functions has great implications for disease prevention and therapy. Virus mutants lacking IFN antagonistic properties represent safe yet highly immunogenic candidate vaccines. Furthermore, novel drugs intercepting viral IFN-antagonists could be used to disarm the viral intruders.

Copper-catalyzed selective hydroamination reactions of alkynes

PubMed Central

Shi, Shi-Liang; Buchwald, Stephen L.

2014-01-01

The development of selective reactions that utilize easily available and abundant precursors for the efficient synthesis of amines is a longstanding goal of chemical research. Despite the centrality of amines in a number of important research areas, including medicinal chemistry, total synthesis and materials science, a general, selective, and step-efficient synthesis of amines is still needed. In this work we describe a set of mild catalytic conditions utilizing a single copper-based catalyst that enables the direct preparation of three distinct and important amine classes (enamines, α-chiral branched alkylamines, and linear alkylamines) from readily available alkyne starting materials with high levels of chemo-, regio-, and stereoselectivity. This methodology was applied to the asymmetric synthesis of rivastigmine and the formal synthesis of several other pharmaceutical agents, including duloxetine, atomoxetine, fluoxetine, and tolterodine. PMID:25515888

Copper-catalysed selective hydroamination reactions of alkynes

NASA Astrophysics Data System (ADS)

Shi, Shi-Liang; Buchwald, Stephen L.

2015-01-01

The development of selective reactions that utilize easily available and abundant precursors for the efficient synthesis of amines is a long-standing goal of chemical research. Despite the centrality of amines in a number of important research areas, including medicinal chemistry, total synthesis and materials science, a general, selective and step-efficient synthesis of amines is still needed. Here, we describe a set of mild catalytic conditions utilizing a single copper-based catalyst that enables the direct preparation of three distinct and important amine classes (enamines, α-chiral branched alkylamines and linear alkylamines) from readily available alkyne starting materials with high levels of chemo-, regio- and stereoselectivity. This methodology was applied to the asymmetric synthesis of rivastigmine and the formal synthesis of several other pharmaceutical agents, including duloxetine, atomoxetine, fluoxetine and tolterodine.

Free Radicals Generated by Ionizing Radiation Signal Nuclear Translocation of p53

NASA Technical Reports Server (NTRS)

Martinez, J. D.; Pennington, M. E.; Craven, M. T.; Warters, R. L.

1997-01-01

The p53 tumor suppressor is a transcription factor that regulates several pathways, which function collectively to maintain the integrity of the genome. Nuclear localization is critical for wild-type function. However, the signals that regulate subcellular localization of p53 have not been identified. Here, we examine the effect of ionizing radiation on the subcellular localization of p53 in two cell lines in which p63 is normally sequestered in the cytoplasm and found that ionizing radiation caused a biphasic translocation response. p53 entered the nucleus 1-2 hours postirradiation (early response), subsequently emerged from the nucleus, and then again entered the nucleus 12-24 hours after the cells had been irradiated (delayed response). These changes in subcellular localization could be completely blocked by the free radical scavenger, WR1065. By comparison, two DNA-damaging agents that do not generate free radicals, mitomycin C and doxorubicin, caused translocation only after 12-24 h of exposure to the drugs, and this effect could not be inhibited by WR1065. Hence, although all three DNA-damaging agents induced relocalization of p53 to the nucleus, only the translocation caused by radiation was sensitive to free radical scavenging. We suggest that the free radicals generated by ionizing radiation can signal p53 translocation to the nucleus.

Dihydroartemisinin Exerts Its Anticancer Activity through Depleting Cellular Iron via Transferrin Receptor-1

PubMed Central

Ba, Qian; Zhou, Naiyuan; Duan, Juan; Chen, Tao; Hao, Miao; Yang, Xinying; Li, Junyang; Yin, Jun; Chu, Ruiai; Wang, Hui

2012-01-01

Artemisinin and its main active metabolite dihydroartemisinin, clinically used antimalarial agents with low host toxicity, have recently shown potent anticancer activities in a variety of human cancer models. Although iron mediated oxidative damage is involved, the mechanisms underlying these activities remain unclear. In the current study, we found that dihydroartemisinin caused cellular iron depletion in time- and concentration-dependent manners. It decreased iron uptake and disturbed iron homeostasis in cancer cells, which were independent of oxidative damage. Moreover, dihydroartemisinin reduced the level of transferrin receptor-1 associated with cell membrane. The regulation of dihydroartemisinin to transferrin receptor-1 could be reversed by nystatin, a cholesterol-sequestering agent but not the inhibitor of clathrin-dependent endocytosis. Dihydroartemisinin also induced transferrin receptor-1 palmitoylation and colocalization with caveolin-1, suggesting a lipid rafts mediated internalization pathway was involved in the process. Also, nystatin reversed the influences of dihydroartemisinin on cell cycle and apoptosis related genes and the siRNA induced downregulation of transferrin receptor-1 decreased the sensitivity to dihydroartemisinin efficiently in the cells. These results indicate that dihydroartemisinin can counteract cancer through regulating cell-surface transferrin receptor-1 in a non-classical endocytic pathway, which may be a new action mechanism of DHA independently of oxidative damage. PMID:22900042

Method for removing strongly adsorbed surfactants and capping agents from metal to facilitate their catalytic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adzic, Radoslav R.; Gong, Kuanping; Cai, Yun

A method of synthesizing activated electrocatalyst, preferably having a morphology of a nanostructure, is disclosed. The method includes safely and efficiently removing surfactants and capping agents from the surface of the metal structures. With regard to metal nanoparticles, the method includes synthesis of nanoparticle(s) in polar or non-polar solution with surfactants or capping agents and subsequent activation by CO-adsorption-induced surfactant/capping agent desorption and electrochemical oxidation. The method produces activated macroparticle or nanoparticle electrocatalysts without damaging the surface of the electrocatalyst that includes breaking, increasing particle thickness or increasing the number of low coordination sites.

Synthesis and evaluation of novel caged DNA alkylating agents bearing 3,4-epoxypiperidine structure.

PubMed

Kawada, Yuji; Kodama, Tetsuya; Miyashita, Kazuyuki; Imanishi, Takeshi; Obika, Satoshi

2012-07-14

Previously, we reported that the 3,4-epoxypiperidine structure, whose design was based on the active site of DNA alkylating antitumor antibiotics, azinomycins A and B, possesses prominent DNA cleavage activity. In this report, novel caged DNA alkylating agents, which were designed to be activated by UV irradiation, were synthesized by the introduction of four photo-labile protecting groups to a 3,4-epoxypiperidine derivative. The DNA cleavage activity and cytotoxicity of the caged DNA alkylating agents were examined under UV irradiation. Four caged DNA alkylating agents showed various degrees of bioactivity depending on the photosensitivity of the protecting groups.

The fast method of Cu-porphyrin complex synthesis for potential use in positron emission tomography imaging

NASA Astrophysics Data System (ADS)

Kilian, Krzysztof; Pęgier, Maria; Pyrzyńska, Krystyna

2016-04-01

Porphyrin based photosensitizers are useful agents for photodynamic therapy and fluorescence imaging of cancer. Additionally, porphyrins are excellent metal chelators, forming stable metalo-complexes and 64Cu isotope can serve as a positron emitter (t1/2 = 12.7 h). The other advantage of 64Cu is its decay characteristics that facilitates the use of 64Cu-porphyrin complex as a therapeutic agent. Thus, 64Cu chelation with porphyrin photosensitizer may become a simple and versatile labeling strategy for clinical positron emission tomography. The present study reports a convenient method for the synthesis of Cu complex with tetrakis(4-carboxyphenyl)porphyrin (TCPP). The experimental conditions for labeling, such as the metal-to-ligand molar ratio, pH and time of reaction were optimized to achieve a high complexation efficiency in a short period of time as possible. In order to accelerate the metallation, the use of substitution reactions of cadmium or lead porphyrin and the presence of reducing agent, such as ascorbic acid, hydroxylamine and flavonoid - morin, were evaluated. The optimum conditions for the synthesis of the copper complex were borate buffer at pH 9 with the addition of 10-fold molar excess, with respect to Cu2 + ions and TCPP and ascorbic acid which resulted in reduction of the reaction time from 30 min to below 1 min.

NIR-Cyanine Dye Linker: a Promising Candidate for Isochronic Fluorescence Imaging in Molecular Cancer Diagnostics and Therapy Monitoring.

PubMed

Komljenovic, Dorde; Wiessler, Manfred; Waldeck, Waldemar; Ehemann, Volker; Pipkorn, Ruediger; Schrenk, Hans-Hermann; Debus, Jürgen; Braun, Klaus

2016-01-01

Personalized anti-cancer medicine is boosted by the recent development of molecular diagnostics and molecularly targeted drugs requiring rapid and efficient ligation routes. Here, we present a novel approach to synthetize a conjugate able to act simultaneously as an imaging and as a chemotherapeutic agent by coupling functional peptides employing solid phase peptide synthesis technologies. Development and the first synthesis of a fluorescent dye with similarity in the polymethine part of the Cy7 molecule whose indolenine-N residues were substituted with a propylene linker are described. Methylating agent temozolomide is functionalized with a tetrazine as a diene component whereas Cy7-cell penetrating peptide conjugate acts as a dienophilic reaction partner for the inverse Diels-Alder click chemistry-mediated ligation route yielding a theranostic conjugate, 3-mercapto-propionic-cyclohexenyl-Cy7-bis-temozolomide-bromide-cell penetrating peptide. Synthesis route described here may facilitate targeted delivery of the therapeutic compound to achieve sufficient local concentrations at the target site or tissue. Its versatility allows a choice of adequate imaging tags applicable in e.g. PET, SPECT, CT, near-infrared imaging, and therapeutic substances including cytotoxic agents. Imaging tags and therapeutics may be simultaneously bound to the conjugate applying click chemistry. Theranostic compound presented here offers a solid basis for a further improvement of cancer management in a precise, patient-specific manner.

NIR-Cyanine Dye Linker: a Promising Candidate for Isochronic Fluorescence Imaging in Molecular Cancer Diagnostics and Therapy Monitoring

PubMed Central

Komljenovic, Dorde; Wiessler, Manfred; Waldeck, Waldemar; Ehemann, Volker; Pipkorn, Ruediger; Schrenk, Hans-Hermann; Debus, Jürgen; Braun, Klaus

2016-01-01

Personalized anti-cancer medicine is boosted by the recent development of molecular diagnostics and molecularly targeted drugs requiring rapid and efficient ligation routes. Here, we present a novel approach to synthetize a conjugate able to act simultaneously as an imaging and as a chemotherapeutic agent by coupling functional peptides employing solid phase peptide synthesis technologies. Development and the first synthesis of a fluorescent dye with similarity in the polymethine part of the Cy7 molecule whose indolenine-N residues were substituted with a propylene linker are described. Methylating agent temozolomide is functionalized with a tetrazine as a diene component whereas Cy7-cell penetrating peptide conjugate acts as a dienophilic reaction partner for the inverse Diels-Alder click chemistry-mediated ligation route yielding a theranostic conjugate, 3-mercapto-propionic-cyclohexenyl-Cy7-bis-temozolomide-bromide-cell penetrating peptide. Synthesis route described here may facilitate targeted delivery of the therapeutic compound to achieve sufficient local concentrations at the target site or tissue. Its versatility allows a choice of adequate imaging tags applicable in e.g. PET, SPECT, CT, near-infrared imaging, and therapeutic substances including cytotoxic agents. Imaging tags and therapeutics may be simultaneously bound to the conjugate applying click chemistry. Theranostic compound presented here offers a solid basis for a further improvement of cancer management in a precise, patient-specific manner. PMID:26722379

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet.

PubMed

Petschenka, Georg; Agrawal, Anurag A

2015-11-07

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na(+)/K(+)-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na(+)/K(+)-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na(+)/K(+)-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na(+)/K(+)-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na(+)/K(+)-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na(+)/K(+)-ATPase, but had systematically reduced effects on Na(+)/K(+)-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na(+)/K(+)-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. © 2015 The Author(s).

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet

PubMed Central

Petschenka, Georg; Agrawal, Anurag A.

2015-01-01

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium–potassium pump (Na+/K+-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na+/K+-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na+/K+-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na+/K+-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na+/K+-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na+/K+-ATPase, but had systematically reduced effects on Na+/K+-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na+/K+-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. PMID:26538594

Translational control of aberrant stress responses as a hallmark of cancer.

PubMed

El-Naggar, Amal M; Sorensen, Poul H

2018-04-01

Altered mRNA translational control is emerging as a critical factor in cancer development and progression. Targeting specific elements of the translational machinery, such as mTORC1 or eIF4E, is emerging as a new strategy for innovative cancer therapy. While translation of most mRNAs takes place through cap-dependent mechanisms, a sub-population of cellular mRNA species, particularly stress-inducible mRNAs with highly structured 5'-UTR regions, are primarily translated through cap-independent mechanisms. Intriguingly, many of these mRNAs encode proteins that are involved in tumour cell adaptation to microenvironmental stress, and thus linked to aggressive behaviour including tumour invasion and metastasis. This necessitates a rigorous search for links between microenvironmental stress and aggressive tumour phenotypes. Under stress, cells block global protein synthesis to preserve energy while maintaining selective synthesis of proteins that support cell survival. One highly conserved mechanism to regulate protein synthesis under cell stress is to sequester mRNAs into cytosolic aggregates called stress granules (SGs), where their translation is silenced. SGs confer survival advantages and chemotherapeutic resistance to tumour cells under stress. Recently, it has been shown that genetically blocking SG formation dramatically reduces tumour invasive and metastatic capacity in vivo. Therefore, targeting SG formation might represent a potential treatment strategy to block cancer metastasis. Here, we present the critical link between selective mRNA translation, stress adaptation, SGs, and tumour progression. Further, we also explain how deciphering mechanisms of selective mRNA translation occurs under cell stress holds great promise for the identification of new targets in the treatment of cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Reducing eIF4E-eIF4G Interactions Restores the Balance Between Protein Synthesis and Actin Dynamics in Fragile X Syndrome Model Mice*

PubMed Central

Santini, Emanuela; Huynh, Thu N.; Longo, Francesco; Koo, So Yeon; Mojica, Edward; D’Andrea, Laura; Bagni, Claudia; Klann, Eric

2018-01-01

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism spectrum disorder. FXS is caused by silencing of the FMR1 gene, which encodes fragile X mental retardation protein (FMRP), an mRNA-binding protein that represses the translation of its target mRNAs. One mechanism by which FMRP represses translation is through its association with cytoplasmic FMRP-interacting protein 1 (CYFIP1), which binds to and sequesters eukaryotic initiation factor 4E (eIF4E). CYFIP1 shuttles between the FMRP–eIF4E complex and the Rac1–Wave regulatory complex, thereby connecting translation regulation to actin dynamics and dendritic spine morphology, which are dysregulated in FXS model mice that lack FMRP. Treating FXS mice with 4EGI-1, which blocks interactions between eIF4E and eukaryotic factor 4G (eIF4G), a critical interacting partner for protein synthesis, reversed defects in hippocampus-dependent memory and spine morphology. We also found that 4EGI-1 normalized the phenotypes of enhanced metabotropic glutamate receptor (mGluR)-mediated long-term depression (LTD), upregulated Rac1–p21-activated kinase (PAK)–cofilin signaling, altered actin dynamics, and dysregulated CYFIP1/eIF4E and CYFIP1/Rac1 interactions in FXS mice. Our findings are consistent with the idea that an imbalance of protein synthesis and actin dynamics contributes to pathophysiology in FXS mice, and suggest that targeting eIF4E may be a strategy for treating FXS. PMID:29114037

Low-cost fabrication of ternary CuInSe{sub 2} nanocrystals by colloidal route using a novel combination of volatile and non-volatile capping agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chawla, Parul; Narain Sharma, Shailesh, E-mail: shailesh@nplindia.org; Singh, Son

2014-11-15

Wet-route synthesis of CuInSe{sub 2} (CISe) nanocrystals has been envisaged with the utilization of the unique combination of coordinating ligand and non coordinating solvent. Our work demonstrates the formation of a single-phase, nearly stoichiometric and monodispersive, stable and well-passivated colloidal ternary CISe nanocrystals (band gap (E{sub g})∼1.16 eV) using a novel combination of ligands; viz. volatile arylamine aniline and non-volatile solvent 1-octadecene. The synthesis and growth conditions have been manoeuvred using the colligative properties of the mixture and thus higher growth temperature (∼250 °C) could be attained that promoted larger grain growth. The beneficial influence of the capping agents (anilinemore » and 1-octadecene) on the properties of chalcopyrite nanocrystals has enabled us to pictorally model the structural, morphological and optoelectronic aspects of CISe nanoparticles. - Graphical abstract: Without resorting to any post-selenization process and using the colligative properties of the mixture comprising of volatile aniline and non-volatile 1-octadecene to manoeuvre the growth conditions to promote Ostwald ripening, a single phase, monodispersive and nearly stoichiometric ternary CISe nanocrystals are formed by wet-synthesis route. - Highlights: • Wet-route synthesis of CISe nanocrystals reported without post-selenization process. • Single-phase, stable and well-passivated colloidal ternary CISe nanocrystals formed. • Novel combination of capping agents: volatile aniline and non-volatile 1-octadecene. • Higher growth temperature attained using the colligative properties of the mixture. • Metallic salts presence explains exp. and theoretical boiling point difference.« less

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Kolsky, Kathryn L.; Mausner, Leonard F.; Srivastava, Suresh C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N, N, N', N'-tetra acetic acid.

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Mausner, Leonard F.; Srivastava, Suresh C.

1994-01-01

Cyclo agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N',N'-tetra acetic acid.

Development of a PET Prostate-Specific Membrane Antigen Imaging Agent: Preclinical Translation for Future Clinical Application

DTIC Science & Technology

2016-10-01

small-molecule peptidomimetic imaging agents labeled with positron emitting fluorine- 18 . These data will enable the filing of an exploratory IND...outcome. 15. SUBJECT TERMS Prostate Cancer, Prostate Specific Membrane Antigen (PSMA), Fluorine- 18 , Molecular Imaging, Radiotracer, Automated...Synthesis, Phosphoramidate, Inhibitor, Peptide Mimic, Peptidomimetic 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18 . NUMBER OF PAGES 19a

Synthesis and potent in vitro activity of novel 1H-benzimidazoles as anti-MRSA agents.

PubMed

Karataş, Hacer; Alp, Mehmet; Yildiz, Sulhiye; Göker, Hakan

2012-08-01

A new class of 1H-benzimidazolecarboxamidines was synthesized and evaluated for in vitro antibacterial and antifungal activities, including drug-resistant bacterial strains. The most potent compound (32) has the same ratio of anti-MRSA activity as Vancomycin (minimal inhibitory concentrations value 0.78 μg/mL). The mechanism of action for 1H-benzimidazolecarboxamidine appears to be different from existing antibacterial agents. These compounds have potential for development as a new class of potent anti-MRSA agent. © 2012 John Wiley & Sons A/S.

4-haloethenylphenyl tropane:serotonin transporter imaging agents

DOEpatents

Goodman, Mark M.; Martarello, Laurent

2005-01-18

A series of compounds in the 4-fluoroalkyl-3-halophenyl nortropanes and 4-haloethenylphenyl tropane families are described as diagnostic and therapeutic agents for diseases associated with serotonin transporter dysfunction. These compounds bind to serotonin transporter protein with high affinity and selectivity. The invention provides methods of synthesis which incorporate radioisotopic halogens at a last step which permit high radiochemical yield and maximum usable product life. The radiolabeled compounds of the invention are useful as imaging agents for visualizing the location and density of serotonin transporter by PET and SPECT imaging.

Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass - the "hydrothermal pump hypothesis"

NASA Astrophysics Data System (ADS)

Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim

2018-03-01

Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis).

Potential New Ligand Systems for Binding Uranyl Ions in Seawater Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arnold, John

2014-12-13

Work began this quarter on a new project involving a combined computational and biosynthetic approach to selective recognition of uranyl ion in aqueous solution. This project exploits the results of computational studies to discover new ligand classes. Synthetic studies will follow to generate target systems for uranyl binding and determination of binding constants. The process will be iterative, with results from computation informing synthesis, and vice versa. The theme of the ligand classes to be examined initially will be biologically based. New phosphonate-containing α-amino acid N-carboxyanhydride (NCA) monomers were used recently to prepare well-defined phosphonate-containing poly-peptides and block copolypeptides. Ourmore » first approach is to utilize these phosphate- and phosphonate-containing NCAs for the coordination of uranyl. The work includes the laboratory-scale preparation of a series of NCAs and the full thermodynamic and spectroscopic characterization of the resulting uranyl complexes. We are also evaluating the sequestering activity in different physiological and environmental conditions of these copolymers as well as their biodegradability.« less

Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

DOE PAGES

Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; ...

2014-10-26

Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu + accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotopemore » labeling demonstrated that sequestered Cu + became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.« less

The Development of High Transition Temperature Superconducting Ceramic Thick Films and Wire Composites

DTIC Science & Technology

1991-12-02

number of protein or sugar agents were experimented with including Agar, pectin, carboxymethylcellulose, gelatin, alginic acid, xanthan gum , guar gum ...I) Introduction and Description of Scientific Goals 1 II) Material and Powder Synthesis 1 A) Freeze Dried Fabrication of Powders 1 B) Utilization of...composites. II). Material and Powder Synthesis The availability of a reliable technique for producing large quantities of phase pure, submicron powders

Mechanisms of Oxygen Toxicity at the Cellular Level.

DTIC Science & Technology

1982-06-30

exposed and measured using glucose as the sole carbon source. Addition of SH containing reducing agents (cysteine, lipoic acid or dithiothreitol) before...of a Few Seconds. Biotechnology and Bioengineering 16:1645-1657 (1974). (28) Brown, O.R. Failure of Lipoic Acid to Protect Against Cellular Oxygen...respiration, and fatty acid synthesis. The interruption of fatty acid synthesis is not the result of inactivation of the fatty acid synthetase enzyme complex

An easy access to 2-Amino-5,6-dihydro-3H-pyrimidin-4-one building blocks: the reaction under conventional and microwave conditions.

PubMed

Ostras, Konstantin S; Gorobets, Nikolay Yu; Desenko, Sergey M; Musatov, Vladimir I

2006-08-01

A new one-stage fast multicomponent synthesis of title compounds leads to products in 21-55% isolated yields under both conventional and microwave conditions. The primary amino group in the building blocks can be easily acylated by various usual electophilic agents that can be utilized in the synthesis of diverse heterocylic compounds libraries.

Advances in the synthesis of α-quaternary α-ethynyl α-amino acids.

PubMed

Boibessot, Thibaut; Bénimélis, David; Meffre, Patrick; Benfodda, Zohra

2016-09-01

α-Quaternary α-ethynyl α-amino acids are an important class of non-proteinogenic amino acids that play an important role in the development of peptides and peptidomimetics as therapeutic agents and in the inhibition of enzyme activities. This review provides an overview of the literature concerning synthesis and applications of α-quaternary α-ethynyl α-amino acids covering the period from 1977 to 2015.

Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope

PubMed Central

Helmann, John D.

2016-01-01

Summary Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σW is most closely associated with membrane-active agents, σX with cationic antimicrobial peptide resistance, and σV with resistance to lysozyme. Here, I highlight the role of the σM regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes. Studies of these cell envelope stress responses provide insights into how bacteria acclimate to the presence of antibiotics. PMID:26901131

Encapsulation of nanoclusters in dried gel materials via an inverse micelle/sol gel synthesis

DOEpatents

Martino, Anthony; Yamanaka, Stacey A.; Kawola, Jeffrey S.; Showalter, Steven K.; Loy, Douglas A.

1998-01-01

A dried gel material sterically entrapping nanoclusters of a catalytically active material and a process to make the material via an inverse micelle/sol-gel synthesis. A surfactant is mixed with an apolar solvent to form an inverse micelle solution. A salt of a catalytically active material, such as gold chloride, is added along with a silica gel precursor to the solution to form a mixture. To the mixture are then added a reducing agent for the purpose of reducing the gold in the gold chloride to atomic gold to form the nanoclusters and a condensing agent to form the gel which sterically entraps the nanoclusters. The nanoclusters are normally in the average size range of from 5-10 nm in diameter with a monodisperse size distribution.

Cellulose as an adhesion agent for the synthesis of lignin aerogel with strong mechanical performance, Sound-absorption and thermal Insulation

PubMed Central

Wang, Chao; Xiong, Ye; Fan, Bitao; Yao, Qiufang; Wang, Hanwei; Jin, Chunde; Sun, Qingfeng

2016-01-01

The lignin aerogels that are both high porosity and compressibility would have promising implications for bioengineering field to sound-adsorption and damping materials; however, creating this aerogel had a challenge to adhesive lignin. Here we reported cellulose as green adhesion agent to synthesize the aerogels with strong mechanical performance. Our approach—straightforwardly dissolved in ionic liquids and simply regenerated in the deionized water—causes assembly of micro-and nanoscale and even molecule level of cellulose and lignin. The resulting lignin aerogels exhibit Young’s modulus up to 25.1 MPa, high-efficiency sound-adsorption and excellent thermal insulativity. The successful synthesis of this aerogels developed a path for lignin to an advanced utilization. PMID:27562532

New target for inhibition of bacterial RNA polymerase: 'switch region'.

PubMed

Srivastava, Aashish; Talaue, Meliza; Liu, Shuang; Degen, David; Ebright, Richard Y; Sineva, Elena; Chakraborty, Anirban; Druzhinin, Sergey Y; Chatterjee, Sujoy; Mukhopadhyay, Jayanta; Ebright, Yon W; Zozula, Alex; Shen, Juan; Sengupta, Sonali; Niedfeldt, Rui Rong; Xin, Cai; Kaneko, Takushi; Irschik, Herbert; Jansen, Rolf; Donadio, Stefano; Connell, Nancy; Ebright, Richard H

2011-10-01

A new drug target - the 'switch region' - has been identified within bacterial RNA polymerase (RNAP), the enzyme that mediates bacterial RNA synthesis. The new target serves as the binding site for compounds that inhibit bacterial RNA synthesis and kill bacteria. Since the new target is present in most bacterial species, compounds that bind to the new target are active against a broad spectrum of bacterial species. Since the new target is different from targets of other antibacterial agents, compounds that bind to the new target are not cross-resistant with other antibacterial agents. Four antibiotics that function through the new target have been identified: myxopyronin, corallopyronin, ripostatin, and lipiarmycin. This review summarizes the switch region, switch-region inhibitors, and implications for antibacterial drug discovery. Copyright © 2011 Elsevier Ltd. All rights reserved.

Synthesis of fluorine-18 labeled rhodamine B: A potential PET myocardial perfusion imaging agent

PubMed Central

Heinrich, Tobias K.; Gottumukkala, Vijay; Snay, Erin; Dunning, Patricia; Fahey, Frederic H; Treves, S. Ted; Packard, Alan B.

2009-01-01

There is considerable interest in developing an 18F-labeled PET myocardial perfusion agent. Rhodamine dyes share several properties with 99mTc-MIBI, the most commonly used single-photon myocardial perfusion agent, suggesting that an 18F-labeled rhodamine dye might prove useful for this application. In addition to being lipophilic cations, like 99mTc-MIBI, rhodamine dyes are known to accumulate in the myocardium and are substrates for Pgp, the protein implicated in MDR1 multidrug resistance. As the first step in determining whether 18F-labeled rhodamines might be useful as myocardial perfusion agents for PET, our objective was to develop synthetic methods for preparing the 18F-labeled compounds so that they could be evaluated in vivo. Rhodamine B was chosen as the prototype compound for development of the synthesis because the ethyl substituents on the amine moieties of rhodamine B protect them from side reactions, thus eliminating the need to include (and subsequently remove) protecting groups. The 2′-[18F]fluoroethyl ester of rhodamine B was synthesized by heating rhodamine B lactone with [18F]fluoroethyltosylate in acetonitrile at 165°C for 30 min.using [18F]fluoroethyl tosylate, which was prepared by the reaction of ethyleneglycol ditosylate with Kryptofix 2.2.2, K2CO3, and [18F]NaF in acetonitrile for 10 min. at 90°C. The product was purified by semi-preparative HPLC to produce the 2′-[18F]-fluoroethylester in >97% radiochemical purity with a specific activity of 1.3 GBq/μmol, an isolated decay corrected yield of 35%, and a total synthesis time of 90 min. PMID:19783150

Water-free synthesis of polyurethane foams using highly reactive diisocyanates derived from 5-hydroxymethylfurfural.

PubMed

Neumann, Christopher N D; Bulach, Winfried D; Rehahn, Matthias; Klein, Roland

2011-09-01

This paper reports on the synthesis of a new highly reactive diisocyanate monomer based on hydroxymethylfurfural. It further describes its catalyst-free conversion to linear-chain thermoplastic polyurethanes as well as to cross-linked polyurethane foams. In addition, a novel strategy for the synthesis of polyurethane foams without the necessity of using water is developed. Nitrogen is utilized herein as blowing agent which is formed during Curtius rearrangement of a new furan based carboxylic azide into its corresponding diisocyanate. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of long T₁ silicon nanoparticles for hyperpolarized ²⁹Si magnetic resonance imaging.

PubMed

Atkins, Tonya M; Cassidy, Maja C; Lee, Menyoung; Ganguly, Shreyashi; Marcus, Charles M; Kauzlarich, Susan M

2013-02-26

We describe the synthesis, materials characterization, and dynamic nuclear polarization (DNP) of amorphous and crystalline silicon nanoparticles for use as hyperpolarized magnetic resonance imaging (MRI) agents. The particles were synthesized by means of a metathesis reaction between sodium silicide (Na₄Si₄) and silicon tetrachloride (SiCl₄) and were surface functionalized with a variety of passivating ligands. The synthesis scheme results in particles of diameter ∼10 nm with long size-adjusted ²⁹Si spin-lattice relaxation (T₁) times (>600 s), which are retained after hyperpolarization by low-temperature DNP.

Synthesis of Long-T1 Silicon Nanoparticles for Hyperpolarized 29Si Magnetic Resonance Imaging

PubMed Central

Atkins, Tonya M.; Cassidy, Maja C.; Lee, Menyoung; Ganguly, Shreyashi; Marcus, Charles M.; Kauzlarich, Susan M.

2013-01-01

We describe the synthesis, materials characterization and dynamic nuclear polarization (DNP) of amorphous and crystalline silicon nanoparticles for use as hyperpolarized magnetic resonance imaging (MRI) agents. The particles were synthesized by means of a metathesis reaction between sodium silicide (Na4Si4) and silicon tetrachloride (SiCl4) and were surface functionalized with a variety of passivating ligands. The synthesis scheme results in particles of diameter ~10 nm with long size-adjusted 29Si spin lattice relaxation (T1) times (> 600 s), which are retained after hyperpolarization by low temperature DNP. PMID:23350651

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

PubMed Central

Rigamonti, Marco Giulio

2015-01-01

Summary The first stereoselective synthesis of lippidulcines A, B and C has been accomplished starting from (+)-hernandulcin, which has been prepared on a multigram scale. The previously assigned absolute configurations have been confirmed. The key steps of this synthesis are based on a modified version of the Kornblum–DeLaMare rearrangement, and on a highly regioselective and stereoselective ketone reduction with the MeCBS reagent. The taste evaluations indicate that none of these sesquiterpenes are sweet, instead the lippidulcine A is a cooling agent with a mint after taste. PMID:26664632

Sequestering the Gravitino: Neutralino Dark Matter in Gauge Mediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craig, Nathaniel J.; /Stanford U., Dept. Phys.; Green, Daniel

2008-08-15

In conventional models of gauge-mediated supersymmetry breaking, the lightest supersymmetric particle (LSP) is invariably the gravitino. However, if the supersymmetry breaking sector is strongly coupled, conformal sequestering may raise the mass of the gravitino relative to the remaining soft supersymmetry-breaking masses. In this letter, we demonstrate that such conformal dynamics in gauge-mediated theories may give rise to satisfactory neutralino dark matter while simultaneously solving the flavor and {mu}/B{mu} problems.

Pharmacokinetic Models for the Elimination of Drinking Water Contaminants from the Body,

DTIC Science & Technology

1990-03-01

that are sequestered in the bones (lead, barium), in certain soft tissues such as the kidney ( cadmium ), and in the adipose tissue (DDT...slow" component (sequestered in 3 bone or in adipose tissue ). Finally, much more attention must be given to differences among I individuals and among...lead from bone, effectively reducing the half-life. Fasting or starvation can mobilize toxicants 3 stored in adipose tissue . Competition for enzyme

Genome Sequence of Carbon Dioxide-Sequestering Serratia sp. Strain ISTD04 Isolated from Marble Mining Rocks.

PubMed

Kumar, Manish; Gazara, Rajesh Kumar; Verma, Sandhya; Kumar, Madan; Verma, Praveen Kumar; Thakur, Indu Shekhar

2016-10-20

The Serratia sp. strain ISTD04 has been identified as a carbon dioxide (CO 2 )-sequestering bacterium isolated from marble mining rocks in the Umra area, Rajasthan, India. This strain grows chemolithotrophically on media that contain sodium bicarbonate (NaHCO 3 ) as the sole carbon source. Here, we report the genome sequence of 5.07 Mb Serratia sp. ISTD04. Copyright © 2016 Kumar et al.

Budget Issues: Effects of the Fiscal Year 1990 Sequester on the Department of Education. Fact Sheet for the Chairman, Committee on the Budget, House of Representatives.

ERIC Educational Resources Information Center

General Accounting Office, Washington, DC.

The Balanced Budget and Emergency Deficit Control Act of 1985, as amended, establishes deficit targets to lead to a balanced unified budget by fiscal year 1993. If the Office of Management and Budget projects a deficit in excess of the target amount plus $10 billion, the President must issue a sequester order to reduce budget resources…

An étude on global vacuum energy sequester

DOE PAGES

D’Amico, Guido; Kaloper, Nemanja; Padilla, Antonio; ...

2017-09-18

Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. The original proposal was based on using global Lagrange multipliers, but later a local formulation was provided. Subsequently other interesting claims of a different non-local approach to the cosmological constant problem were made, based again on global Lagrange multipliers. We examine some of these proposals and find their mutual relationship. We explain that the proposals which do not treat the cosmological constant counterterm as a dynamical variable require fine tunings to have acceptable solutions. Furthermore,more » the counterterm often needs to be retuned at every order in the loop expansion to cancel the radiative corrections to the cosmological constant, just like in standard GR. These observations are an important reminder of just how the proposal of vacuum energy sequester avoids such problems.« less

Bark extract mediated green synthesis of silver nanoparticles: Evaluation of antimicrobial activity and antiproliferative response against osteosarcoma.

PubMed

Nayak, Debasis; Ashe, Sarbani; Rauta, Pradipta Ranjan; Kumari, Manisha; Nayak, Bismita

2016-01-01

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV-vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative (Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae) and Gram positive (Bacillus subtilis) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of polycarbonate-r-polyethylene glycol copolymer for templated synthesis of mesoporous TiO2 films.

PubMed

Patel, Rajkumar; Kim, Jinkyu; Lee, Chang Soo; Kim, Jong Hak

2014-12-01

We synthesized a novel polycarbonate Z-r-polyethylene glycol (PCZ-r-PEG) copolymer by solution polycondensation. Successful synthesis of PCZ-r-PEG copolymer was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H-NMR), gel permeation chromatography (GPC), and transmission electron microscopy (TEM). PCZ-r-PEG copolymer was used as a structure-directing agent for fabrication of mesoporous thin film containing a titanium dioxide (TiO2) layer. To control the porosity of the resultant inorganic layer, the ratio of titanium(IV) isopropoxide (TTIP) to PCZ-r-PEG copolymer was varied. The structure and porosity of the resulting mesoporous films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Mesoporous TiO2 films fabricated on an F-doped tin oxide (FTO) surface were used as photoanodes for quasi-solid-state dye-sensitized solar cells (qssDSSCs). The highest efficiency achieved was 3.3% at 100 mW/cm2 for a film thickness of 750 nm, which is high considering the thickness of TiO2 film, indicating the importance of the structure-directing agent.

Flame-Sprayed Y2O3 Films with Metal-EDTA Complex Using Various Cooling Agents

NASA Astrophysics Data System (ADS)

Komatsu, Keiji; Toyama, Ayumu; Sekiya, Tetsuo; Shirai, Tomoyuki; Nakamura, Atsushi; Toda, Ikumi; Ohshio, Shigeo; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

2017-01-01

In this study, yttrium oxide (Y2O3) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H2-O2 combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y2O3 films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y2O3 films showed only a few cracks and minor peeling in their microstructures. For instance, the Y2O3 film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film's temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit's temperatures.

Synthesis and DNA cleavage activity of Bis-3-chloropiperidines as alkylating agents.

PubMed

Zuravka, Ivonne; Roesmann, Rolf; Sosic, Alice; Wende, Wolfgang; Pingoud, Alfred; Gatto, Barbara; Göttlich, Richard

2014-09-01

Nitrogen mustards are an important class of bifunctional alkylating agents routinely used in chemotherapy. They react with DNA as electrophiles through the formation of highly reactive aziridinium ion intermediates. The antibiotic 593A, with potential antitumor activity, can be considered a naturally occurring piperidine mustard containing a unique 3-chloropiperidine ring. However, the total synthesis of this antibiotic proved to be rather challenging. With the aim of designing simplified analogues of this natural product, we developed an efficient bidirectional synthetic route to bis-3-chloropiperidines joined by flexible, conformationally restricted, or rigid diamine linkers. The key step involves an iodide-catalyzed double cyclization of unsaturated bis-N-chloroamines to simultaneously generate both piperidine rings. Herein we describe the synthesis and subsequent evaluation of a series of novel nitrogen-bridged bis-3-chloropiperidines, enabling the study of the impact of the linker structure on DNA alkylation properties. Our studies reveal that the synthesized compounds possess DNA alkylating abilities and induce strand cleavage, with a strong preference for guanine residues. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of surfactant-free electrostatically stabilized gold nanoparticles by plasma-induced liquid chemistry

NASA Astrophysics Data System (ADS)

Patel, J.; Němcová, L.; Maguire, P.; Graham, W. G.; Mariotti, D.

2013-06-01

Plasma-induced non-equilibrium liquid chemistry is used to synthesize gold nanoparticles (AuNPs) without using any reducing or capping agents. The morphology and optical properties of the synthesized AuNPs are characterized by transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy. Plasma processing parameters affect the particle shape and size and the rate of the AuNP synthesis process. Particles of different shapes (e.g. spherical, triangular, hexagonal, pentagonal, etc) are synthesized in aqueous solutions. In particular, the size of the AuNPs can be tuned from 5 nm to several hundred nanometres by varying the initial gold precursor (HAuCl4) concentration from 2.5 μM to 1 mM. In order to reveal details of the basic plasma-liquid interactions that lead to AuNP synthesis, we have measured the solution pH, conductivity and hydrogen peroxide (H2O2) concentration of the liquid after plasma processing, and conclude that H2O2 plays the role of the reducing agent which converts Au+3 ions to Au0 atoms, leading to nucleation growth of the AuNPs.

Mustard Gas: Its Pre-World War I History

NASA Astrophysics Data System (ADS)

Duchovic, Ronald J.; Vilensky, Joel A.

2007-06-01

Mustard gas is perhaps the best-known chemical warfare agent and is commonly associated with World War I, both in its first use in warfare and its first synthesis. Although the former is correct, the latter is not. We review here the history of the repeated synthesis of mustard gas by 19th century European chemists. The techniques developed by these chemists were the ones relied upon by both the Central Powers and the Allies to manufacture this agent during World War I. Further, a historical review of mustard gas synthesis highlights the increasing sophistication of the chemical sciences. In particular, during the latter half of the 19th century, the concepts of atomic mass, chemical periodicity, and chemical structure underwent a rapid development that culminated in the application of quantum mechanics to chemistry in the 20th century. A comparison is made of the molecular formula for mustard gas from the 19th century with that of the 21st century, demonstrating that the concept of atomic mass has undergone significant refinement over this period of time.

Final Technical Report: Targeting DOE-Relevant Ions with Supramolecular Strategies, DE-SC0010555

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman-James, Kristin

The effectiveness of three popular supramolecular strategies to selectively target negatively charged ions (anions) was evaluated. Ions of interest included oxo anions, particularly sulfate, that hamper nuclear waste remediation. Three objectives were pursued using a simple building block strategies and by strategically placing anion-binding sites at appropriate positions on organic host molecules. The goal of the first objective was to assess the influence of secondary, tertiary and quaternized amines on binding tetrahedral anions using mixed amide/amine macrocyclic and urea/amine hosts containing aromatic or heteroaromatic spacers. Objective 2 focused on the design of ion pair hosts, using mixed macrocyclic anion hostsmore » joined through polyether linkages. Objective 3 was to explore the synthesis of new metal-linked extended macrocyclic frameworks to leverage anion binding. Key findings were that smaller 24-membered macrocycles provided the most complementary binding for sulfate ion and mixed urea/amine chelates showed enhanced binding over amide corollaries in addition to being highly selective for SO 4 2- in the presence of small quantities of water. In addition to obtaining prototype metal-linked macrocyclic anion hosts, a new dipincer ligand was designed that can be used to link macrocyclic or other supramolecular hosts in extended frameworks. When the tetraamide-based pincers are bound to two metal ions, an interesting phenomenon occurs. Upon deprotonation of the amides, two new protons appear between adjacent carbonyl pairs on the ligand, which may modify the chemistry, and metal-metal interactions in the complexes. Gel formation occurred for some of these extended hosts, and the physical properties are currently under investigation. The new tetracarboxamide-based pincers can also provide basic frameworks for double macrocycles capable of binding ion pairs as well as for binding metal ions and exploring intermetallic interactions through the pyrazine π system. Additionally appendages capable of influencing solvation effects can be introduced, and a number of other potential applications can be realized in areas such as soft materials chemistry, catalysis, sensing, and proton switches, the latter for binding and release of targeted guests. These findings provide a better foundation for understanding the selective binding of anions by targeted placement of hydrogen binding sites, and the strengths and weaknesses of various functional groups, that will allow for more the design of more effective anion sequestering agents. Our design strategy also used simple, cost-effective building blocks for host synthesis to allow for scale-up should real-world applications be forthcoming.« less

Synthesis and characterization of nanocrystalline mordenite, high silica zeolite RHO, and copper faujasite

NASA Astrophysics Data System (ADS)

Hincapie Palacio, Beatriz Omaira

Mordenite is a zeolite that has been used as a selective adsorbent and as a catalyst. In reactions where the diffusion of reagents into the pore system is the rate-determining step, nanoparticles of the catalyst improve the reaction rate. Mordenite with a crystal diameter smaller than 100 nm has been prepared by the modification of different synthetic parameters such as the source of aluminum, the presence of seeds, the use of low temperatures (150°C vs. 170°C), longer crystallization times (24 h vs. 96 h), and different silica to alumina ratios (10--30). The decrease in the crystal diameter of the prepared mordenite was monitored by the application of the Scherrer equation that relates the broadness of the X-ray diffraction peaks to crystal sizes. Zeolite RHO with an initial silica to alumina ratio (SAR) higher than 20 has been prepared. EDTA, citric acid, and tartaric acid have been used as complexing agents in the synthesis of zeolite RHO. Crystallization time increases (from 48 h to 900 h) with increasing the silica to alumina ratios (SAR) of the initial gel (SAR: 10.8 to 30) and by adding complexing agents. Complexing agents favor the formation of small crystals (0.8 mum) with increased silica to alumina ratio (final SAR: 4.5 vs. 4.0 without complexing agents). The products were characterized by XRD, FESEM, EDX, FTIR, and in-situ XRD. Copper containing faujasite has been successfully prepared for the first time using a direct synthesis method. Ammonium hydroxide was used to form a copper complex that was later mixed with the reacting gel. Crystallization took place at 85°C for 11 days. The copper containing faujasite obtained was characterized by XRD, FESEM, EDX, EPR, FTIR, TPR, and BET. According to the XRD pattern only FAU type zeolite was obtained. According to TPR experiments, the reduction temperature for Cu2+ ions present in Cu-FAU prepared by direct synthesis was 70 K higher than for Cu-FAU prepared by ion-exchange. This difference can be due to the different location of the copper ions in the supercages or in the sodalite cages of the faujasite.

Streamlined Total Synthesis of Trioxacarcins and Its Application to the Design, Synthesis, and Biological Evaluation of Analogues Thereof. Discovery of Simpler Designed and Potent Trioxacarcin Analogues.

PubMed

Nicolaou, K C; Chen, Pengxi; Zhu, Shugao; Cai, Quan; Erande, Rohan D; Li, Ruofan; Sun, Hongbao; Pulukuri, Kiran Kumar; Rigol, Stephan; Aujay, Monette; Sandoval, Joseph; Gavrilyuk, Julia

2017-11-01

A streamlined total synthesis of the naturally occurring antitumor agents trioxacarcins is described, along with its application to the construction of a series of designed analogues of these complex natural products. Biological evaluation of the synthesized compounds revealed a number of highly potent, and yet structurally simpler, compounds that are effective against certain cancer cell lines, including a drug-resistant line. A novel one-step synthesis of anthraquinones and chloro anthraquinones from simple ketone precursors and phenylselenyl chloride is also described. The reported work, featuring novel chemistry and cascade reactions, has potential applications in cancer therapy, including targeted approaches as in antibody-drug conjugates.

Design, synthesis, and biological evaluation of combretabenzodiazepines: a novel class of anti-tubulin agents.

PubMed

Galli, Ubaldina; Travelli, Cristina; Aprile, Silvio; Arrigoni, Elena; Torretta, Simone; Grosa, Giorgio; Massarotti, Alberto; Sorba, Giovanni; Canonico, Pier Luigi; Genazzani, Armando A; Tron, Gian Cesare

2015-02-12

In the present manuscript, starting from the 1,4-benzodiazepin-2-one nucleus, a privileged structure in medicinal chemistry, we have synthesized a novel class of cis-locked combretastatins named combreatabenzodiazepines. They show similar cytotoxic and antitubulin activity compared to combretastatin A-4 in neuroblastoma cells, showing a better pharmacokinetic profile. This class of compounds has therefore the potential for further development as antitubulin agents.

Promoter-Based Theranostics for Prostate Cancer

DTIC Science & Technology

2015-10-01

PD/PI(s) or senior/key personnel since the last reporting period?  Marty Pomper Ended Title: PSMA -Based Cancer Imaging Agents Time Commitments...for PSMA . Aim #2: Synthetic optimization of the best compounds of Aim 1 en route to GMP and/or facilitated use. Aim #3: Synthesis and evaluation of a...series of homo- and heterodimeric imaging agents for PSMA . Title: BETR Therapy of Herpesvirus-associated Tumors Time Commitments

Repurposing Toremifene for Treatment of Oral Bacterial Infections.

PubMed

Gerits, Evelien; Defraine, Valerie; Vandamme, Katleen; De Cremer, Kaat; De Brucker, Katrijn; Thevissen, Karin; Cammue, Bruno P A; Beullens, Serge; Fauvart, Maarten; Verstraeten, Natalie; Michiels, Jan

2017-03-01

The spread of antibiotic resistance and the challenges associated with antiseptics such as chlorhexidine have necessitated a search for new antibacterial agents against oral bacterial pathogens. As a result of failing traditional approaches, drug repurposing has emerged as a novel paradigm to find new antibacterial agents. In this study, we examined the effects of the FDA-approved anticancer agent toremifene against the oral bacteria Porphyromonas gingivalis and Streptococcus mutans We found that the drug was able to inhibit the growth of both pathogens, as well as prevent biofilm formation, at concentrations ranging from 12.5 to 25 μM. Moreover, toremifene was shown to eradicate preformed biofilms at concentrations ranging from 25 to 50 μM. In addition, we found that toremifene prevents P. gingivalis and S. mutans biofilm formation on titanium surfaces. A time-kill study indicated that toremifene is bactericidal against S. mutans Macromolecular synthesis assays revealed that treatment with toremifene does not cause preferential inhibition of DNA, RNA, or protein synthesis pathways, indicating membrane-damaging activity. Biophysical studies using fluorescent probes and fluorescence microscopy further confirmed the membrane-damaging mode of action. Taken together, our results suggest that the anticancer agent toremifene is a suitable candidate for further investigation for the development of new treatment strategies for oral bacterial infections. Copyright © 2017 American Society for Microbiology.

Role of different chelating agent in synthesis of copper doped tin oxide (Cu-SnO2) nanoparticles

NASA Astrophysics Data System (ADS)

Saravanakumar, B.; Anusiya, A.; Rani, B. Jansi; Ravi, G.; Yuvakkumar, R.

2018-05-01

An attempt was made to synthesis the copper doped tin oxide (Cu-SnO2) nanoparticles by adopting different chelating agents (NaOH, KOH and C2H2O4) by Sol-gel process. The synthesized products were characterized by XRD, Photoluminescence (PL), Infra- Red (FTIR) and SEM analysis. The XRD confirms the formation of Cu-SnO2 shows the maximum peak at 33.8° with lattice plane (101). The PL peak at 361 and 382 nm due to the recombination of electron in conduction band to valence band infers the optical properties. The IR spectra correspond to the peak at 551 and 620 cm-1 attributed to the characteristics peak for Cu-SnO2 nanoparticles. The SEM images for all three Cu-SnO2 nanoparticles formed by three chelating agent (NaOH, KOH and C2H2O4) facilitates the formation mechanism and the chelating agent Oxalic acid results in formation of nano flowers with diverse layers orientated in random direction. Further SEM studies reveal that, the Cu-SnO2 nanoparticles formed by oxalic acid could posses high surface area with large number layered structured enables the better electrochemical properties and its applications.

Stimuli-sensitive hydrogels: ideal carriers for chronobiology and chronotherapy.

PubMed

Peppas, Nicholas A; Leobandung, William

2004-01-01

The development of solid-phase peptide synthesis in the early 1960s and recombinant DNA technology in the early 1970s boosted the scientific interest of utilizing proteins and peptides as potential therapeutic agents to battle poorly controlled diseases. While there has been rapid progress in the development and synthesis of new proteins and peptides as potential therapeutic agents, the formulation and development of the associated delivery systems is lacking. The development of delivery systems is equally important due to the problems of stability, low bioavailability and short half-life of proteins and peptides. The main problem in this field is that low stability leads to low bioavailability. In this review we draw attention to chrono-pharmacological drug-delivery systems, which can be used to match the delivery of therapeutic agents with the biological rhythm. They are very important especially in endocrinology and in vaccine therapy. We show that the treatment of hypopituitary dwarfism by administration of human growth-hormone-releasing hormone (GHRH) is more effective when GHRH is administered in a pulsatile manner that exhibits a period characteristic of the patient's circadian rhythm. Here we examine how to design novel chrono-pharmacological drug-delivery systems that should be able to release the therapeutic agents at predetermined intervals.

Dissociation of the Tubulin-sequestering and Microtubule Catastrophe-promoting Activities of Oncoprotein 18/Stathmin

PubMed Central

Howell, Bonnie; Larsson, Niklas; Gullberg, Martin; Cassimeris, Lynne

1999-01-01

Oncoprotein 18/stathmin (Op18) has been identified recently as a protein that destabilizes microtubules, but the mechanism of destabilization is currently controversial. Based on in vitro microtubule assembly assays, evidence has been presented supporting conflicting destabilization models of either tubulin sequestration or promotion of microtubule catastrophes. We found that Op18 can destabilize microtubules by both of these mechanisms and that these activities can be dissociated by changing pH. At pH 6.8, Op18 slowed microtubule elongation and increased catastrophes at both plus and minus ends, consistent with a tubulin-sequestering activity. In contrast, at pH 7.5, Op18 promoted microtubule catastrophes, particularly at plus ends, with little effect on elongation rates at either microtubule end. Dissociation of tubulin-sequestering and catastrophe-promoting activities of Op18 was further demonstrated by analysis of truncated Op18 derivatives. Lack of a C-terminal region of Op18 (aa 100–147) resulted in a truncated protein that lost sequestering activity at pH 6.8 but retained catastrophe-promoting activity. In contrast, lack of an N-terminal region of Op18 (aa 5–25) resulted in a truncated protein that still sequestered tubulin at pH 6.8 but was unable to promote catastrophes at pH 7.5. At pH 6.8, both the full length and the N-terminal–truncated Op18 bound tubulin, whereas truncation at the C-terminus resulted in a pronounced decrease in tubulin binding. Based on these results, and a previous study documenting a pH-dependent change in binding affinity between Op18 and tubulin, it is likely that tubulin sequestering observed at lower pH resulted from the relatively tight interaction between Op18 and tubulin and that this tight binding requires the C-terminus of Op18; however, under conditions in which Op18 binds weakly to tubulin (pH 7.5), Op18 stimulated catastrophes without altering tubulin subunit association or dissociation rates, and Op18 did not depolymerize microtubules capped with guanylyl (α, β)-methylene diphosphonate–tubulin subunits. We hypothesize that weak binding between Op18 and tubulin results in free Op18, which is available to interact with microtubule ends and thereby promote catastrophes by a mechanism that likely involves GTP hydrolysis. PMID:9880330

Green route for synthesis of multifunctional fluorescent carbon dots from Tulsi leaves and its application as Cr(VI) sensors, bio-imaging and patterning agents.

PubMed

Bhatt, Shreya; Bhatt, Madhuri; Kumar, Anshu; Vyas, Gaurav; Gajaria, Tejal; Paul, Parimal

2018-07-01

We report a one pot green strategy for the synthesis of carbon dots using tulsi leaves and their potential application in sensing of Cr(VI) selectively. The detection mechanism is based on the phenomenon called inner filter effect (IFE) and a good linear static quenching was observed in the range of 1.6 μM to 50 μM with a detection limit of 4.5 ppb. The reversible switching in fluorescence has been tested and a good recovery in fluorescence was observed up to three consecutive cycles upon addition of ascorbic acid as reducing agent. Also the low toxicity, high fluorescence and photostabilty of the CDs make them excellent imaging and patterning agent. The acid and alkali resistant property of these CDs makes it suitable for real sample analysis. The fluorescent CDs were applied for successful detection of Cr(VI) in water with spike-recoveries ranging from 93 to 99%. Copyright © 2018 Elsevier B.V. All rights reserved.

In situ growth of metal particles on 3D urchin-like WO3 nanostructures.

PubMed

Xi, Guangcheng; Ye, Jinhua; Ma, Qiang; Su, Ning; Bai, Hua; Wang, Chao

2012-04-18

Metal/semiconductor hybrid materials of various sizes and morphologies have many applications in areas such as catalysis and sensing. Various organic agents are necessary to stabilize metal nanoparticles during synthesis, which leads to a layer of organic compounds present at the interfaces between the metal particles and the semiconductor supports. Generally, high-temperature oxidative treatment is used to remove the organics, which can extensively change the size and morphology of the particles, in turn altering their activity. Here we report a facile method for direct growth of noble-metal particles on WO(3) through an in situ redox reaction between weakly reductive WO(2.72) and oxidative metal salts in aqueous solution. This synthetic strategy has the advantages that it takes place in one step and requires no foreign reducing agents, stabilizing agents, or pretreatment of the precursors, making it a practical method for the controlled synthesis of metal/semiconductor hybrid nanomaterials. This synthetic method may open up a new way to develop metal-nanoparticle-loaded semiconductor composites. © 2012 American Chemical Society

Α-aryl-N-alkyl nitrones, as potential agents for stroke treatment: synthesis, theoretical calculations, antioxidant, anti-inflammatory, neuroprotective, and brain-blood barrier permeability properties.

PubMed

Chioua, Mourad; Sucunza, David; Soriano, Elena; Hadjipavlou-Litina, Dimitra; Alcázar, Alberto; Ayuso, Irene; Oset-Gasque, María Jesús; González, María Pilar; Monjas, Leticia; Rodríguez-Franco, María Isabel; Marco-Contelles, José; Samadi, Abdelouahid

2012-01-12

We report the synthesis, theoretical calculations, the antioxidant, anti-inflammatory, and neuroprotective properties, and the ability to cross the blood-brain barrier (BBB) of (Z)-α-aryl and heteroaryl-N-alkyl nitrones as potential agents for stroke treatment. The majority of nitrones compete with DMSO for hydroxyl radicals, and most of them are potent lipoxygenase inhibitors. Cell viability-related (MTT assay) studies clearly showed that nitrones 1-3 and 10 give rise to significant neuroprotection. When compounds 1-11 were tested for necrotic cell death (LDH release test) nitrones 1-3, 6, 7, and 9 proved to be neuroprotective agents. In vitro evaluation of the BBB penetration of selected nitrones 1, 2, 10, and 11 using the PAMPA-BBB assay showed that all of them cross the BBB. Permeable quinoline nitrones 2 and 3 show potent combined antioxidant and neuroprotective properties and, therefore, can be considered as new lead compounds for further development in specific tests for potential stroke treatment.

Solvothermal synthesis of ZnO nanoparticles and anti-infection application in vivo.

PubMed

Bai, Xiangyang; Li, Linlin; Liu, Huiyu; Tan, Longfei; Liu, Tianlong; Meng, Xianwei

2015-01-21

Zinc oxide nanoparticles (ZnONPs) have been widely studied as the bacteriostatic reagents. However, synthesis of small ZnO nanoparticles with good monodispersion and stability in aqueous solution is still a challenge. Anti-infection research of ZnONPs used as antibacterial agent in vivo is rare. In this paper, a novel, sustainable, and simple method to synthesize ZnO nanoparticles with good monodispersion in aqueous low-temperature conditions and with a small molecule agent is reported. Inhibition zone test and the minimum inhibitory concentration test were performed to examine the antibacterial activity of ZnONPs against bacteria Staphylococcus aureus and Escherichia coli in vitro. For further application in vivo, low cytotoxicity and low acute toxicity in mice of ZnO were demonstrated. Finally, 4 nm ZnONPs combined with poly(vinyl alcohol) gel was used as antibacterial agent in rodent elytritis model, and significant anti-infection effect was proven. In one word, the present research would shed new light on the designing of antibacterial materials like ZnO with promising application in disinfection.

Controlled synthesis of flexible graphene aerogels macroscopic monolith as versatile agents for wastewater treatment

NASA Astrophysics Data System (ADS)

Dong, Shuying; Xia, Longji; Guo, Teng; Zhang, Fangyuan; Cui, Lingfang; Su, Xianfa; Wang, Dong; Guo, Wei; Sun, Jianhui

2018-07-01

Emerging applications for environmental purification require agents that not only possess high decontamination efficiency, but also are capable of withstanding mechanical deformation without secondary pollution and degradation of performance. To this end, we have controlled synthesis of mechanically flexible graphene aerogel (GA) by vacuum freeze-drying of their hydrogel precursors obtained from heating the aqueous mixtures of graphene oxide (GO) and Vitamin C (VC) without stirring. Through the adaptable process conditions, such as the particle size of carbon, GO concentration, dosage of reducing agent and solution pH, the highly porous, ultralight and mechanically flexible GA are synthesized. Owing to the porous, robust and stable structure, the resulting GA show very promising performance in water purification including enrichment of organic liquid solvents (alcohols, oil and alkanes), removal of hexavalent chromium Cr(VI) and purified industrial wastewater, as well as flexible conductors. The successful creation of the GA may provide new insights into the design of carbon-based aerogels for various applications, as the GA can be prepared via a very simple procedure and available in macroscopic diverse morphologies with tunable porosity.

Biomedical Applications of Nanomaterials as Therapeutics.

PubMed

Ng, Cheng-Teng; Baeg, Gyeong-Hun; Yu, Liya E; Ong, Choon-Nam; Bay, Boon-Huat

2018-01-01

As nanomaterials possess attractive physicochemical properties, immense research efforts have been channeled towards their development for biological and biomedical applications. In particular, zinc nanomaterials (nZnOs) have shown great potential for use in in the medical and pharmaceutical fields, and as tools for novel antimicrobial treatment, thereby capitalizing on their unique antimicrobial effects. We conducted a literature search using databases to retrieve the relevant articles related to the synthesis, properties and current applications of nZnOs in the diagnosis and treatment of diseases. A total of 86 publications were selected for inclusion in this review. Besides studies on the properties and the methodology for the synthesis of nZnOs, many studies have focused on the application of nZnOs as delivery agents, biosensors and antimicrobial agents, as well as in bioimaging. This review gives an overview of the current development of nZnOs for their potential use as theranostic agents. However, more comprehensive studies are needed to better assess the valuable contributions and the safety of nZnOs in nanomedicine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Macromolecular and Dendrimer Based Magnetic Resonance Contrast Agents

PubMed Central

Bumb, Ambika; Brechbiel, Martin W.; Choyke, Peter

2010-01-01

Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20–25 years, a number of gadolinium based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution and targeting of dendrimer-based MR contrast agents are also discussed. PMID:20590365

Synthesis of a new hardener agent for self-healing epoxy resins

NASA Astrophysics Data System (ADS)

Raimondo, Marialuigia; Guadagno, Liberata; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Agovino, Anna

2014-05-01

Actually, the development of smart composites capable of self-repair in aeronautical structures is still at the planning stage owing to complex issues to overcome. One of the critical points in the development of self-healing epoxy resin is related to the impossibility to employ primary amines as hardeners. In this paper, the synthesis of a new hardener for self-healing resins is shown together with applicability conditions/ranges.

Copper-catalyzed aerobic decarboxylative sulfonylation of cinnamic acids with sodium sulfinates: stereospecific synthesis of (E)-alkenyl sulfones.

PubMed

Jiang, Qing; Xu, Bin; Jia, Jing; Zhao, An; Zhao, Yu-Rou; Li, Ying-Ying; He, Na-Na; Guo, Can-Cheng

2014-08-15

A copper-catalyzed aerobic decarboxylative sulfonylation of alkenyl carboxylic acids with sodium sulfinates is developed. This study offers a new and expedient strategy for stereoselective synthesis of (E)-alkenyl sulfones that are widely present in biologically active natural products and therapeutic agents. Moreover, the transformation is proposed to proceed via a radical process and exhibits a broad substrate scope and good functional group tolerance.

Synthesis and Biological Evaluation of Benzochromenopyrimidinones as Cholinesterase Inhibitors and Potent Antioxidant, Non-Hepatotoxic Agents for Alzheimer's Disease.

PubMed

Dgachi, Youssef; Bautista-Aguilera, Oscar M; Benchekroun, Mohamed; Martin, Hélène; Bonet, Alexandre; Knez, Damijan; Godyń, Justyna; Malawska, Barbara; Gobec, Stanislav; Chioua, Mourad; Janockova, Jana; Soukup, Ondrej; Chabchoub, Fakher; Marco-Contelles, José; Ismaili, Lhassane

2016-05-14

We report herein the straightforward two-step synthesis and biological assessment of novel racemic benzochromenopyrimidinones as non-hepatotoxic, acetylcholinesterase inhibitors with antioxidative properties. Among them, compound 3Bb displayed a mixed-type inhibition of human acetylcholinesterase (IC50 = 1.28 ± 0.03 μM), good antioxidant activity, and also proved to be non-hepatotoxic on human HepG2 cell line.

The study of interaction of modified fatty acid with {sup 99m}Tc in alcoholic media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skuridin, V. S.; Stasyuk, E. S.; Varlamova, N. V.

2016-08-02

The paper presents the results of laboratory research aimed at the development of methods of synthesis of new radiodiagnostic agents based on modified fatty acid labelled with technetium-99m intended for scintigraphic evaluation of myocardial metabolism. In particular, the interaction of substance with {sup 99m}Tc in alcoholic media and the use of ethanol as solvent in the synthesis of the radiopharmaceutical were studied.

Gold(III) complexes with hydroxyquinoline, aminoquinoline and quinoline ligands: Synthesis, cytotoxicity, DNA and protein binding studies.

PubMed

Martín-Santos, Cecilia; Michelucci, Elena; Marzo, Tiziano; Messori, Luigi; Szumlas, Piotr; Bednarski, Patrick J; Mas-Ballesté, Rubén; Navarro-Ranninger, Carmen; Cabrera, Silvia; Alemán, José

2015-12-01

In this article, we report on the synthesis and the chemical and biological characterization of novel gold(III) complexes based on hydroxyl- or amino-quinoline ligands that are evaluated as prospective anticancer agents. To gain further insight into their reactivity and possible mode of action, their interactions with model proteins and standard nucleic acid molecules were investigated. Copyright © 2015 Elsevier Inc. All rights reserved.

Chemistry, Biochemistry, Pharmacology, and Toxicology of CS and Synthesis of Its Novel Analogs

DTIC Science & Technology

2007-10-01

fluorine and fluorine -containing groups have been synthesized using microwave irradiation and novel catalysts. The structures and physical properties and...safe, and biologically more potent CS analogs. To this end, the synthesis of a novel group of CS-agents incorporating fluorine and fluorine ...CONCLUSION The new CS-analogs are expected to be more potent than CS. This observation is based on the following considerations. First, fluorine is

Direct reductive amination of aldehyde bisulfite adducts induced by 2-picoline borane: application to the synthesis of a DPP-IV inhibitor.

PubMed

Faul, Margaret; Larsen, Rob; Levinson, Adam; Tedrow, Jason; Vounatsos, Filisaty

2013-02-15

Aldehyde-bisulfite adducts dervied from unstable parent aldehydes were reductively alkylated in a direct fashion with a variety of amines. This approach features the use of 2-picoline borane as the reducing agent and a protic solvent for the reaction media and has been successfully applied to the synthesis of a DPP-IV inhibitor and a variety of other amines.

Plant mediated green synthesis: modified approaches.

PubMed

Das, Ratul Kumar; Brar, Satinder Kaur

2013-11-07

Plant mediated green synthesis of different metallic nanoparticles has emerged as one of the options for implementation of green chemistry principles, and successfully made an important contribution towards green nanotechnology. However, beyond the synthesis and application aspects, the science of green synthesis has carried some wrong perceptions in an unforeseen fashion. In this review, some of the key issues related to the green synthesis of metallic nanoparticles employing plants as reducing/capping agents have been addressed. Random selection of plants and its overall impact on the different aspects of green synthesis have been discussed. Emphasis is given to the setting of some standard selection criteria to be adopted for selecting a plant for use in green synthesis. How selection of a plant can positively or negatively influence both procedure and products of a green synthesis process is the prime concern of this article. In addition to selection, the key issue of biocompatibility associated with green synthesized metallic nanoparticles has been considered. Both selection of plant and biocompatibility were reconsidered for their minute details in terms of synthesis, analysis and data interpretation in the green synthesis approach. The key factors capable of fine tuning the core meaning of "green" in the synthesis of any metallic nanoparticles were taken into consideration. This article is an effort towards keeping the core meaning of green synthesis.

Agroforestry: a sustainable environmental practice for carbon sequestration under the climate change scenarios-a review.

PubMed

Abbas, Farhat; Hammad, Hafiz Mohkum; Fahad, Shah; Cerdà, Artemi; Rizwan, Muhammad; Farhad, Wajid; Ehsan, Sana; Bakhat, Hafiz Faiq

2017-04-01

Agroforestry is a sustainable land use system with a promising potential to sequester atmospheric carbon into soil. This system of land use distinguishes itself from the other systems, such as sole crop cultivation and afforestation on croplands only through its potential to sequester higher amounts of carbon (in the above- and belowground tree biomass) than the aforementioned two systems. According to Kyoto protocol, agroforestry is recognized as an afforestation activity that, in addition to sequestering carbon dioxide (CO 2 ) to soil, conserves biodiversity, protects cropland, works as a windbreak, and provides food and feed to human and livestock, pollen for honey bees, wood for fuel, and timber for shelters construction. Agroforestry is more attractive as a land use practice for the farming community worldwide instead of cropland and forestland management systems. This practice is a win-win situation for the farming community and for the environmental sustainability. This review presents agroforestry potential to counter the increasing concentration of atmospheric CO 2 by sequestering it in above- and belowground biomass. The role of agroforestry in climate change mitigation worldwide might be recognized to its full potential by overcoming various financial, technical, and institutional barriers. Carbon sequestration in soil by various agricultural systems can be simulated by various models but literature lacks reports on validated models to quantify the agroforestry potential for carbon sequestration.

Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary Kronrad

2004-10-31

This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of sitemore » qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.« less

Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary Kronrad

2006-01-31

This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of sitemore » qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.« less

Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary Kronrad

2005-04-30

This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of sitemore » qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.« less

Enhancement of Terrestrial Carbon Sinks throught the Reclamation of Abandoned Mined Lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gary Kronrad

2006-06-30

This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of sitemore » qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.« less

Synthesis of gold nanochains via photoactivation technique and their catalytic applications.

PubMed

Sinha, Arun Kumar; Basu, Mrinmoyee; Sarkar, Sougata; Pradhan, Mukul; Pal, Tarasankar

2013-05-15

The article reports a simple photoactivation technique for the synthesis of chain like assembly of spherical Au nanocrystals using a nontoxic biochemical, β-cyclodextrin under ~365 nm UV-light irradiation. Under UV irradiation, β-cyclodextrin acts as a reducing as well as capping agent and eventually becomes a stabilizing linker for Au nanoparticles. The UV-visible spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopic techniques are employed to systematically characterize the Au nanochains. Additionally, it is shown that the Au nanocrystals act as an effective catalyst for the reduction in nitrobenzene to aniline and methylene blue to leuco methylene blue in presence of suitable reducing agent. The catalytic reduction reactions and kinetic parameters are evaluated from UV-visible spectroscopy. Copyright © 2013 Elsevier Inc. All rights reserved.

Oxidative acylation using thioacids

NASA Technical Reports Server (NTRS)

Liu, R.; Orgel, L. E.

1997-01-01

Several important prebiotic reactions, including the coupling of amino acids into polypeptides by the formation of amide linkages, involve acylation. Theae reactions present a challenge to the understanding of prebiotic synthesis. Condensation reactions relying on dehydrating agents are either inefficient in aqueous solution or require strongly acidic conditions and high temperatures. Activated amino acids such as thioester derivatives have therefore been suggested as likely substrates for prebiotic peptide synthesis. Here we propose a closely related route to amide bond formation involving oxidative acylation by thioacids. We find that phenylalanine, leucine and phenylphosphate are acylated efficiently in aqueous solution by thioacetic acid and an oxidizing agent. From a prebiotic point of view, oxidative acylation has the advantage of proceeding efficiently in solution and under mild conditions. We anticipate that oxidative acylation should prove to be a general method for activating carboxylic acids, including amino acids.

Synthesis and antimicrobial studies of novel derivatives of 4-(4-formyl-3-phenyl-1H-pyrazol-1-yl)benzoic acid as potent anti-Acinetobacter baumanni agents

PubMed Central

Allison, Devin; Delancey, Evan; Ramey, Hunter; Williams, Conrad; Alsharif, Zakeyah Ali; Al-khattabi, Hessa; Ontko, Allyn; Gilmore, David

2017-01-01

Microbial resistance to antibiotics is a global concern. The World Health Organization (WHO) has identified antimicrobial resistance as one the three greatest threats for human beings in the 21st century. Without urgent and coordinated action, the world is moving toward a post-antibiotic era, in which normal infections or minor injuries may become fatal. In an effort to find new agents, we report the synthesis and antimicrobial activities of 40 novel 1,3-diphenyl pyrazole derivatives. These compounds have shown zones of growth inhibition up to 85 mm against Acinetobacter baumannii. We tested the active compounds against this Gram-negative bacterium in minimum inhibitory concentration (MIC) tests and found activity with concentration as low as 4 μg/mL. PMID:28065568

Synthesis and antimicrobial studies of novel derivatives of 4-(4-formyl-3-phenyl-1H-pyrazol-1-yl)benzoic acid as potent anti-Acinetobacter baumannii agents.

PubMed

Allison, Devin; Delancey, Evan; Ramey, Hunter; Williams, Conrad; Alsharif, Zakeyah Ali; Al-Khattabi, Hessa; Ontko, Allyn; Gilmore, David; Alam, Mohammad A

2017-02-01

Microbial resistance to antibiotics is a global concern. The World Health Organization (WHO) has identified antimicrobial resistance as one the three greatest threats for human beings in the 21st century. Without urgent and coordinated action, the world is moving toward a post-antibiotic era, in which normal infections or minor injuries may become fatal. In an effort to find new agents, we report the synthesis and antimicrobial activities of 40 novel 1,3-diphenyl pyrazole derivatives. These compounds have shown zones of growth inhibition up to 85mm against Acinetobacter baumannii. We tested the active compounds against this Gram-negative bacterium in minimum inhibitory concentration (MIC) tests and found activity with concentration as low as 4μg/mL. Published by Elsevier Ltd.

Ga@C-dots as an antibacterial agent for the eradication of Pseudomonas aeruginosa

PubMed Central

Kumar, Vijay Bhooshan; Natan, Michal; Jacobi, Gila; Porat, Ze’ev; Banin, Ehud; Gedanken, Aharon

2017-01-01

The opportunistic pathogen Pseudomonas aeruginosa causes infections that are difficult to treat by antibiotic therapy. This research article reports on the synthesis of gallium (Ga) doped in carbon (C)-dots (Ga@C-dots) and their antimicrobial activity against free-living P. aeruginosa bacteria. The synthesis of Ga@C-dots was carried out by sonicating molten Ga (for 2.5 h) in polyethylene glycol-400, which acts as both a medium and carbon source. The resultant Ga@C-dots, having an average diameter of 9±2 nm, showed remarkably enhanced antibacterial activity compared with undoped C-dots. This was reflected by the much lower concentration of Ga doped within Ga@C-dots which was required for full inhibition of the bacterial growth. These results highlight the possibility of using Ga@C-dots as potential antimicrobial agents. PMID:28176980

Benzyl Alcohol-Mediated Versatile Method to Fabricate Nonstoichiometric Metal Oxide Nanostructures.

PubMed

Qamar, Mohammad; Adam, Alaaldin; Azad, Abdul-Majeed; Kim, Yong-Wah

2017-11-22

Nanostructured metal oxides with cationic or anionic deficiency find applications in a wide range of technological areas including the energy sector and environment. However, a facile route to prepare such materials in bulk with acceptable reproducibility is still lacking; many synthesis techniques are still only bench-top and cannot be easily scaled-up. Here, we report that the benzyl alcohol (BA)-mediated method is capable of producing a host of nanostructured metal oxides (MO x , where M = Ti, Zn, Ce, Sn, In, Ga, or Fe) with inherent nonstoichiometry. It employs multifunctional BA as a solvent, a reducing agent, and a structure-directing agent. Depending on the oxidation states of metal, elemental or nonstoichiometric oxide forms are obtained. Augmented photoelectrochemical oxidation of water under visible light by some of these nonstoichiometric oxides highlights the versatility of the BA-mediated synthesis protocol.

Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope.

PubMed

Helmann, John D

2016-04-01

Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σ(W) is most closely associated with membrane-active agents, σ(X) with cationic antimicrobial peptide resistance, and σ(V) with resistance to lysozyme. Here, I highlight the role of the σ(M) regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes. Studies of these cell envelope stress responses provide insights into how bacteria acclimate to the presence of antibiotics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced antimicrobial activity in biosynthesized ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Kumari, Niraj; Kumari, Priti; Jha, Anal K.; Prasad, K.

2018-05-01

Biological synthesis of different metallic and/or oxide nanoparticles and their applications especially in agriculture and biomedical sciences are gaining prominence nowadays due to their handy and reproducible synthetic protocols which are cost-effective and eco-friendly. In this work, green synthesis of zinc oxide nanoparticles (ZnO NPs) using the alcoholic extract of Azadirachta indica as a reducing and stabilizing agent has been presented. Formation of ZnO NPs was confirmed by X-ray diffraction, scanning and transmission electron microscopy techniques. The phytochemicals responsible for nano-transformation were principally alkaloids, flavanoids, terpenoids, tannins and organic acids present in the Azadirachta indica leaves. The synthesized ZnO NPs were used for antimicrobial assays by disc diffusion method against Staphylococcus aureus and Candida albicans. Results showed that ZnO NPs may act as antimicrobial agent especially against skin infections.

Encapsulation of nanoclusters in dried gel materials via an inverse micelle/sol gel synthesis

DOEpatents

Martino, A.; Yamanaka, S.A.; Kawola, J.S.; Showalter, S.K.; Loy, D.A.

1998-09-29

A dried gel material sterically entrapping nanoclusters of a catalytically active material and a process to make the material via an inverse micelle/sol-gel synthesis are disclosed. A surfactant is mixed with an apolar solvent to form an inverse micelle solution. A salt of a catalytically active material, such as gold chloride, is added along with a silica gel precursor to the solution to form a mixture. To the mixture are then added a reducing agent for the purpose of reducing the gold in the gold chloride to atomic gold to form the nanoclusters and a condensing agent to form the gel which sterically entraps the nanoclusters. The nanoclusters are normally in the average size range of from 5--10 nm in diameter with a monodisperse size distribution. 1 fig.

Synthesis and biological evaluation of sialyl-oligonucleotide conjugates targeting leukocyte B trans-membranal receptor CD22 as delivery agents for nucleic acid drugs.

PubMed

St-Pierre, Gabrielle; Pal, Sudip; Østergaard, Michael E; Zhou, Tianyuan; Yu, Jinghua; Tanowitz, Michael; Seth, Punit P; Hanessian, Stephen

2016-06-01

Antisense oligonucleotides (ASOs) modified with ligands which target cell surface receptors have the potential to significantly improve potency in the target tissue. This has recently been demonstrated using triantennary N-acetyl d-galactosamine conjugated ASOs. CD22 is a cell surface receptor expressed exclusively on B cells thus presenting an attractive target for B cell specific delivery of drugs. Herein, we reported the synthesis of monovalent and trivalent ASO conjugates with biphenylcarbonyl (BPC) modified sialic acids and their study as ASO delivery agents into B cells. CD22 positive cells exhibited reduced potency when treated with ligand modified ASOs and mechanistic examination suggested reduced uptake into cells potentially as a result of sequestration of ASO by other cell-surface proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Tetracyclines, sulfonamides and metronidazole].

PubMed

Pérez-Trallero, Emilio; Iglesias, Luis

2003-11-01

Tetracyclines form a group of natural and semisynthetic products that acts inhibiting the bacterial protein synthesis. They are bacteriostatic agents, exhibiting activity against a wide range of organisms, but they are at the present of limited use because of their acquired resistance. Doxycycline is currently the most frequently used tetracycline in human medicine and it is included in the List of Essential Medicines of the World Health Organization. Sulfonamides are synthetic, broad-spectrum bacteriostatic antibiotics. They were the first effective systemic antimicrobial agents. Their mode of action is based on the inhibition of DNA synthesis. Due to their toxicity and high adquired resistance their use is currently very low. Metronidazole is the main compound of 5-nitroimidazole family. It is a very active bactericidal antibiotic against anaerobic and some microaerophilic bacteria and it is still very useful in the treatment of bacterian and parasitic infections.

Design, Synthesis, and Properties of a Potent Inhibitor of Pseudomonas aeruginosa Deacetylase LpxC.

PubMed

Piizzi, Grazia; Parker, David T; Peng, Yunshan; Dobler, Markus; Patnaik, Anup; Wattanasin, Som; Liu, Eugene; Lenoir, Francois; Nunez, Jill; Kerrigan, John; McKenney, David; Osborne, Colin; Yu, Donghui; Lanieri, Leanne; Bojkovic, Jade; Dzink-Fox, JoAnn; Lilly, Maria-Dawn; Sprague, Elizabeth R; Lu, Yipin; Wang, Hongming; Ranjitkar, Srijan; Xie, Lili; Wang, Bing; Glick, Meir; Hamann, Lawrence G; Tommasi, Ruben; Yang, Xia; Dean, Charles R

2017-06-22

Over the past several decades, the frequency of antibacterial resistance in hospitals, including multidrug resistance (MDR) and its association with serious infectious diseases, has increased at alarming rates. Pseudomonas aeruginosa is a leading cause of nosocomial infections, and resistance to virtually all approved antibacterial agents is emerging in this pathogen. To address the need for new agents to treat MDR P. aeruginosa, we focused on inhibiting the first committed step in the biosynthesis of lipid A, the deacetylation of uridyldiphospho-3-O-(R-hydroxydecanoyl)-N-acetylglucosamine by the enzyme LpxC. We approached this through the design, synthesis, and biological evaluation of novel hydroxamic acid LpxC inhibitors, exemplified by 1, where cytotoxicity against mammalian cell lines was reduced, solubility and plasma-protein binding were improved while retaining potent anti-pseudomonal activity in vitro and in vivo.

Imidazoline and imidazolidine nitroxides as controlling agents in nitroxide-mediated pseudoliving radical polymerization

NASA Astrophysics Data System (ADS)

Edeleva, M. V.; Marque, S. R. A.; Bagryanskaya, E. G.

2018-04-01

Controlled, or pseudoliving, radical polymerization provides unique opportunities for the synthesis of structurally diverse polymers with a narrow molecular-weight distribution. These reactions occur under relatively mild conditions with broad tolerance to functional groups in the monomers. The nitroxide-mediated pseudoliving radical polymerization is of particular interest for the synthesis of polymers for biomedical applications. This review briefly describes one of the mechanisms of controlled radical polymerization. The studies dealing with the use of imidazoline and imidazolidine nitroxides as controlling agents for nitroxide-mediated pseudoliving radical polymerization of various monomers are summarized and analyzed. The publications addressing the key steps of the controlled radical polymerization in the presence of imidazoline and imidazolidine nitroxides and new approaches to nitroxide-mediated polymerization based on protonation of both nitroxides and monomers are considered. The bibliography includes 154 references.

Abroma augusta Linn bark extract-mediated green synthesis of gold nanoparticles and its application in catalytic reduction

NASA Astrophysics Data System (ADS)

Das, Subhajit; Bag, Braja Gopal; Basu, Ranadhir

2015-10-01

The bark extract of Abroma augusta Linn is rich in medicinally important phytochemicals including antioxidants and polyphenols. First one step green synthesis of gold nanoparticles (AuNPs) has been described utilizing the bark extract of Abroma augusta L. and chloroauric acid under very mild reaction conditions. The phytochemicals present in the bark extract acted both as a reducing as well as a stabilizing agent, and no additional stabilizing and capping agents were needed. Detailed characterizations of the stabilized AuNPs were carried out by surface plasmon resonance spectroscopy, high resolution transmission electron microscopy, and X-ray diffraction studies. The catalytic activity of the freshly synthesized gold nanoparticles has been demonstrated for the sodium borohydride reduction of 4-nitrophenol to 4-aminophenol, and the kinetics of the reduction reaction have been studied spectrophotometrically.

Robust one pot synthesis of colloidal silver nanoparticles by simple redox method and absorbance recovered sensing.

PubMed

Salman, Muhammad; Iqbal, Mahwish; El Ashry, El Sayed H; Kanwal, Shamsa

2012-01-01

Conventional synthesis of silver nanoparticles employs a reducing agent and a capping agent. In this report water-soluble silver nanoparticles (AgNPs) were prepared facilely by chemical reduction of Ag(I) ions. 4-Amino-3-(d-gluco-pentitol-1-yl)-4,5-dihydro-1,2,4-triazole-5-thione (AGTT) was used both as reducing and stabilizing agent. Direct heating methodology was found to be more suitable for achieving particles with a hydrodynamic diameter of ~20 nm. AGTT exists as tautomer in solution form and our studies indicate that -NH(2) group is involved in the reduction and stabilization of Ag(+) and thione (Δ=S) group of AGTT is possibly involved in stabilizing the nanoparticles via coordinate covalent linkage. Characterization of synthesized silver nanoparticles was performed by UV-vis, FT-IR and by FESEM. Based on the absorption properties of synthesized AgNPs, we used AgNPs to detect bovine serum albumin (BSA) and AgNPs-BSA composite nanoprobe was further applied to detect Cu(2+) based on absorbance recovery. The proposed method has advantages over existing methods in terms of rapid synthesis and stability of AgNPs and their applications. Analysis is reproducible, cost effective and highly sensitive. The lowest detectable concentration of BSA in this approach is 3 nM, and for Cu(2+) it can detect upto 200 pM. Copyright © 2012 Elsevier B.V. All rights reserved.

Panax ginseng induces human Type I collagen synthesis through activation of Smad signaling.

PubMed

Lee, Jongsung; Jung, Eunsun; Lee, Jiyoung; Huh, Sungran; Kim, Jieun; Park, Mijung; So, Jungwoon; Ham, Younggeun; Jung, Kwangseon; Hyun, Chang-Gu; Kim, Yeong Shik; Park, Deokhoon

2007-01-03

Skin aging appears to be principally related to a decrease in levels of Type I collagen, the primary component of the dermal layer of skin. It is important to introduce an efficient agent for effective management of skin aging; this agent should have the fewest possible side effects and the greatest wrinkle-reducing effect. In the course of screening collagen production-promoting agents, we obtained Panax ginseng C.A. Meyer. This study was designed to investigate the possible collagen production-promoting activities of Panax ginseng C.A. Meyer root extract (PGRE) in human dermal fibroblast cells. As a first step to this end, human COL1A2 promoter luciferase assay was performed in human dermal fibroblast cells. In this assay, PGRE activated human COL1A2 promoter activity in a concentration-dependent manner. Human Type I procollagen synthesis was also induced by PGRE. These results suggest that PGRE promotes collagen production in human dermal fibroblast cells. Additionally, we have attempted to characterize the mechanism of action of PGRE in Type I procollagen synthesis. PGRE was found to induce the phosphorylation of Smad2, an important transcription factor in the production of Type I procollagen. When applied topically in a human skin primary irritation test, PGRE did not induce any adverse reactions. Therefore, based on these results, we suggest the possibility that PGRE may be considered as an attractive, wrinkle-reducing candidate for topical application.

Aggregation of ALS-linked FUS mutant sequesters RNA binding proteins and impairs RNA granules formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takanashi, Keisuke; Yamaguchi, Atsushi, E-mail: atsyama@restaff.chiba-u.jp

Highlights: • Aggregation of ALS-linked FUS mutant sequesters ALS-associated RNA-binding proteins (FUS wt, hnRNP A1, and hnRNP A2). • Aggregation of ALS-linked FUS mutant sequesters SMN1 in the detergent-insoluble fraction. • Aggregation of ALS-linked FUS mutant reduced the number of speckles in the nucleus. • Overproduced ALS-linked FUS mutant reduced the number of processing-bodies (PBs). - Abstract: Protein aggregate/inclusion is one of hallmarks for neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). FUS/TLS, one of causative genes for familial ALS, encodes a multifunctional DNA/RNA binding protein predominantly localized in the nucleus. C-terminal mutations in FUS/TLS cause the retention and the inclusionmore » of FUS/TLS mutants in the cytoplasm. In the present study, we examined the effects of ALS-linked FUS mutants on ALS-associated RNA binding proteins and RNA granules. FUS C-terminal mutants were diffusely mislocalized in the cytoplasm as small granules in transiently transfected SH-SY5Y cells, whereas large aggregates were spontaneously formed in ∼10% of those cells. hnRNP A1, hnRNP A2, and SMN1 as well as FUS wild type were assembled into stress granules under stress conditions, and these were also recruited to FUS mutant-derived spontaneous aggregates in the cytoplasm. These aggregates stalled poly(A) mRNAs and sequestered SMN1 in the detergent insoluble fraction, which also reduced the number of nuclear oligo(dT)-positive foci (speckles) in FISH (fluorescence in situ hybridization) assay. In addition, the number of P-bodies was decreased in cells harboring cytoplasmic granules of FUS P525L. These findings raise the possibility that ALS-linked C-terminal FUS mutants could sequester a variety of RNA binding proteins and mRNAs in the cytoplasmic aggregates, which could disrupt various aspects of RNA equilibrium and biogenesis.« less

Cosmeceuticals for Hyperpigmentation: What is Available?

PubMed Central

Sarkar, Rashmi; Arora, Pooja; Garg, K Vijay

2013-01-01

Cosmeceuticals are topical cosmetic-pharmaceutical hybrids that enhance the beauty through constituents that provide additional health-related benefit. Cosmeceuticals are commonly used for hyperpigmentation. These disorders are generally difficult to treat, hence the need for skin lightening agents including, cosmeceuticals. These agents selectively target hyperplastic melanocytes and inhibit key regulatory steps in melanin synthesis. With the recent safety concern regarding use of hydroquinone, the need for alternative natural, safe and efficacious skin lightening agents is becoming all the more necessary and the article attempts to look at other alternative cosmeceuticals available or maybe upcoming in the future. We carried out a PUBMED search using the following terms “cosmeceuticals, hyperpigmentation, skin lightening agents.” We cited the use of various agents used for the treatment of hyperpigmentation, mainly melasma and post-inflammatory hyperpigmentation. We describe the safety and efficacy of these agents and their advantage over the conventional therapy. PMID:23723597

Biogenic synthesis of metallic nanoparticles and prospects toward green chemistry.

PubMed

Adil, Syed Farooq; Assal, Mohamed E; Khan, Mujeeb; Al-Warthan, Abdulrahman; Siddiqui, Mohammed Rafiq H; Liz-Marzán, Luis M

2015-06-07

The immense importance of nanoparticles and their applications is a strong motivation for exploring new synthetic techniques. However, due to strict regulations that manage the potential environmental impacts greener alternatives for conventional synthesis are the focus of intense research. In the scope of this perspective, a concise discussion about the use of green reducing and stabilizing agents toward the preparation of metal nanoparticles is presented. Reports on the synthesis of noble metal nanoparticles using plant extracts, ascorbic acid and sodium citrate as green reagents are summarized and discussed, pointing toward an urgent need of understanding the mechanistic aspects of the involved reactions.

Green synthesis of silver nanoparticles using tannins

NASA Astrophysics Data System (ADS)

Raja, Pandian Bothi; Rahim, Afidah Abdul; Qureshi, Ahmad Kaleem; Awang, Khalijah

2014-09-01

Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.

TiO2 synthesized by microwave assisted solvothermal method: Experimental and theoretical evaluation

NASA Astrophysics Data System (ADS)

Moura, K. F.; Maul, J.; Albuquerque, A. R.; Casali, G. P.; Longo, E.; Keyson, D.; Souza, A. G.; Sambrano, J. R.; Santos, I. M. G.

2014-02-01

In this study, a microwave assisted solvothermal method was used to synthesize TiO2 with anatase structure. The synthesis was done using Ti (IV) isopropoxide and ethanol without templates or alkalinizing agents. Changes in structural features were observed with increasing time of synthesis and evaluated using periodic quantum chemical calculations. The anatase phase was obtained after only 1 min of reaction besides a small amount of brookite phase. Experimental Raman spectra are in accordance with the theoretical one. Micrometric spheres constituted by nanometric particles were obtained for synthesis from 1 to 30 min, while spheres and sticks were observed after 60 min.

Serinol: small molecule - big impact

PubMed Central

2011-01-01

The amino alcohol serinol (2-amino-1,3-propanediol) has become a common intermediate for several chemical processes. Since the 1940s serinol was used as precursor for synthesis of synthetic antibiotics (chloramphenicol). In the last years, new scopes of applications were discovered. Serinol is used for X-ray contrast agents, pharmaceuticals or for chemical sphingosine/ceramide synthesis. It can either be obtained by chemical processes based on 2-nitro-1,3-propanediol, dihydroxyacetone and ammonia, dihydroxyacetone oxime or 5-amino-1,3-dioxane, or biotechnological application of amino alcohol dehydrogenases (AMDH) or transaminases. This review provides a survey of synthesis, properties and applications for serinol. PMID:21906364

Synthesis and antitumour activity of 4-aminoquinazoline derivatives

NASA Astrophysics Data System (ADS)

Lipunova, G. N.; Nosova, E. V.; Charushin, V. N.; Chupakhin, O. N.

2016-07-01

Pieces of data on the synthesis and antitumour activity of 4-aminoquinazolines are summarized and analyzed. Key methods for the synthesis of these compounds are considered, primarily cyclocondensation of carboxylic acid derivatives, as well as the oxidation of quinazolines and the cyclization of disubstituted thioureas. Improvements of synthetic schemes for erlotinib, gefitinib and lapatinib, which are the best-known pharmaceuticals based on compounds of the title class, are also considered. Synthetic strategies and biological activities for new 4-aminoquinazoline derivatives that are EGFR-tyrosine kinase inhibitors, multiactive compounds, and labelled compounds for use as positron emission tomography (PET) imaging agents are discussed. The bibliography includes 263 references.

Conference Report: ESF-COST High-Level Research Conference Natural Products Chemistry, Biology and Medicine III.

PubMed

Catino, Arthur

2010-12-01

Natural Products Chemistry, Biology and Medicine III was the third conference in a series of events sponsored by the European Science Foundation (ESF) and the European Cooperation in the field of Scientific and Technical Research (COST). Scientists came together from within and outside the EU to present cutting-edge developments in chemical synthesis. Research areas included the synthesis of natural products, methods development, isolation/structural elucidation and chemical biology. As our capacity to produce new chemotherapeutic agents relies on chemical synthesis, this year's conference has never been so timely. This report highlights several of the scientific contributions presented during the meeting.

Effect of the Polymeric Stabilizer in the Aqueous Phase Fischer-Tropsch Synthesis Catalyzed by Colloidal Cobalt Nanocatalysts

PubMed Central

Delgado, Jorge A.; Claver, Carmen; Castillón, Sergio; Curulla-Ferré, Daniel; Godard, Cyril

2017-01-01

A series of small and well defined cobalt nanoparticles were synthesized by the chemical reduction of cobalt salts in water using NaBH4 as a reducing agent and using various polymeric stabilizers. The obtained nanocatalysts of similar mean diameters (ca. 2.6 nm) were fully characterized and tested in the aqueous phase Fischer-Tropsch Synthesis (AFTS). Interestingly, the nature and structure of the stabilizers used during the synthesis of the CoNPs affected the reduction degree of cobalt and the B-doping of these NPs and consequently, influenced the performance of these nanocatalysts in AFTS. PMID:28336892

Gd-complexes of macrocyclic DTPA conjugates of 1,1'-bis(amino)ferrocenes as high relaxivity MRI blood-pool contrast agents (BPCAs).

PubMed

Kim, Hee-Kyung; Park, Ji-Ae; Kim, Kyeong Min; Nasiruzzaman, Sk Md; Kang, Duk-Sik; Lee, Jongmin; Chang, Yongmin; Kim, Tae-Jeong

2010-11-28

We report the synthesis of macrocyclic DTPA conjugates of 1,1'-bis(amino)ferrocenes (1a-b) and their Gd-complexes [Gd(L)(H(2)O)] (2a-b, L = 1a-b) for use as new MRI blood-pool contrast agents. High R(1) relaxivity in HSA as well as high thermodynamic and kinetic stabilities is observed for 2a.

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Mausner, L.F.; Srivastava, S.C.

1994-03-08

Cyclo agents are described which are useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2diamino cyclohexane-N,N,N',N'-tetra acetic acid. No Drawings

Solution synthesis of mixed-metal chalcogenide nanoparticles and spray deposition of precursor films

DOEpatents

Schulz, Douglas L.; Curtis, Calvin J.; Ginley, David S.

2000-01-01

A colloidal suspension comprising metal chalcogenide nanoparticles and a volatile capping agent. The colloidal suspension is made by reacting a metal salt with a chalcogenide salt in an organic solvent to precipitate a metal chalcogenide, recovering the metal chalcogenide, and admixing the metal chalcogenide with a volatile capping agent. The colloidal suspension is spray deposited onto a substrate to produce a semiconductor precursor film which is substantially free of impurities.

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Kolsky, K.L.; Mausner, L.F.; Srivastava, S.C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes are synthesized. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N{prime},N{prime}-tetra acetic acid.

Development of a Multifaceted Ovarian Cancer Therapeutic and Imaging Agent

DTIC Science & Technology

2011-04-01

by 1-ethyl-3- [3-(dimethylamino) propyl ]carbodiimide (EDC) and N-hydroxysulfonosuccinimide (SNHS) at pH 5.5 for 30 min with a molar ratio of...particle-coated migratory substrate that can act as a permanent record of cellular movement. The gold chloride solution was prepared using 0.342 g... Synthesis and clinical Evaluation. Anticancer Agents Med. Chem. McLane, M.A., Joerger, T., Mahmoud, A., 2008. Disintegrins in health and disease. Front

Activation of formylmethanofuran synthesis in cell extracts of Methanobacterium thermoautotrophicum.

PubMed Central

Bobik, T A; Wolfe, R S

1989-01-01

In cell extracts of Methanobacterium thermoautotrophicum, formylmethanofuran (formyl-MFR) synthesis (an essential CO2 fixation reaction that is an early step in CO2 reduction to methane) is subject to a complex activation that involves a heterodisulfide of coenzyme M and N-(7-mercaptoheptanoyl)threonine O3-phosphate (CoM-S-S-HTP). In this paper we report that titanium(III) citrate, a low-potential reducing agent, stimulated CO2 reduction to methane and activated formyl-MFR synthesis in cell extracts. Titanium(III) citrate functioned as the sole source of electrons for formyl-MFR synthesis and enabled this reaction to occur independently of CoM-S-S-HTP. In addition, CoM-S-S-HTP was found to activate an unknown electron carrier that reduced metronidazole. The activation of formyl-MFR synthesis by CoM-S-S-HTP may involve the activation of a low-potential electron carrier. PMID:2921239

DNA synthesis security.

PubMed

Nouri, Ali; Chyba, Christopher F

2012-01-01

It is generally assumed that genetic engineering advances will, inevitably, facilitate the misapplication of biotechnology toward the production of biological weapons. Unexpectedly, however, some of these very advances in the areas of DNA synthesis and sequencing may enable the implementation of automated and nonintrusive safeguards to avert the illicit applications of biotechnology. In the case of DNA synthesis, automated DNA screening tools could be built into DNA synthesizers in order to block the synthesis of hazardous agents. In addition, a comprehensive safety and security regime for dual-use genetic engineering research could include nonintrusive monitoring of DNA sequencing. This is increasingly feasible as laboratories outsource this service to just a few centralized sequencing factories. The adoption of automated, nonintrusive monitoring and surveillance of the DNA synthesis and sequencing pipelines may avert many risks associated with dual-use biotechnology. Here, we describe the historical background and current challenges associated with dual-use biotechnologies and propose strategies to address these challenges.

Synthesis and Characterization of Ionically Crosslinked Elastomers

DTIC Science & Technology

2016-01-01

ionomer with a anionic monomer, and crosslinking by copolymerization with a  hydrophobic  monomer.  While these materials displayed signatures of...Therefore, these RAFT agents should have utility in the  synthesis of  super ‐soft and/or higher damping elastomers.  2. An ionic, divinyl crosslinking

Synthesis of 4-hydroxy-1-methylindole and benzo[b]thiophen-4-ol based unnatural flavonoids as new class of antimicrobial agents.

PubMed

Yadav, Prem P; Gupta, Prasoon; Chaturvedi, A K; Shukla, P K; Maurya, Rakesh

2005-03-01

Synthesis of nitrogen and sulfur heterocyclic mimics of furanoflavonoids have been achieved for the first time. Synthesized flavonoid alkaloids and thiophenyl flavonoids have been screened for antifungal and antibacterial activities. All the test compounds barring 25 exhibited antifungal activity. The compound 19 was the best and showed comparable MICs to the known compound karanjin. Compounds 5, 12, 14 and 22 also showed comparable MIC to karanjin.

Upscaling nitrogen-mycorrhizal effects to quantify CO2 fertilization.

NASA Astrophysics Data System (ADS)

Terrer, C.; Franklin, O.; Kaiser, C.; Vicca, S.; Stocker, B.; Prentice, I. C.; Soudzilovskaia, N.

2016-12-01

Terrestrial ecosystems sequester annually about a quarter of anthropogenic carbon dioxide (CO2) emissions. However, it has been proposed that nitrogen (N) availability will limit plants' capacity to absorb increasing quantities of CO2 in the atmosphere. Experiments in which plants are fumigated with elevated CO2 show contrasting results, leaving open the debate of whether the magnitude of the CO2 fertilization effect will be limited by N. By synthesizing data from CO2 experiments through meta-analysis, we found that the magnitude of the CO2 fertilization effect can be explained based on the interaction between N availability and type of mycorrhizal association. Indeed, N availability is the most important driver of the CO2 fertilization effect, however, plants that associate with ectomycorrhizal fungi can overcome N limitations and grow about 30% more under 650ppm than under 400ppm of atmospheric CO2. On the other hand, plants that associate with arbuscular mycorrhizal fungi show no CO2 fertilization effect under low N availability. Using this framework, we quantified biomass responses to CO2 as a function of the soil parameters that determine N availability for the two mycorrhizal types. Then, by overlaying the distribution of mycorrhizal plants with global projections of the soil parameters that determine N availability, we estimated the amount of extra CO2 that terrestrial plants can sequester in biomass for an increase in CO2, as well as the distribution of the CO2 fertilization effect. This synthesis reconciles contrasting views of the role of N in terrestrial carbon uptake and emphasizes the plant control on N availability through interaction with ectomycorrhizal fungi. Large-scale ecosystem models should account for the influence of nitrogen and mycorrhizae reported here, which will improve representation of the CO2 fertilization effect, critical for projecting ecosystem responses and feedbacks to climate change.

A Survival Strategy for Pseudomonas aeruginosa That Uses Exopolysaccharides To Sequester and Store Iron To Stimulate Psl-Dependent Biofilm Formation

PubMed Central

Yu, Shan; Wei, Qing; Zhao, Tianhu; Guo, Yuan

2016-01-01

ABSTRACT Exopolysaccharide Psl is a critical biofilm matrix component in Pseudomonas aeruginosa, which forms a fiber-like matrix to enmesh bacterial communities. Iron is important for P. aeruginosa biofilm development, yet it is not clearly understood how iron contributes to biofilm development. Here, we showed that iron promoted biofilm formation via elevating Psl production in P. aeruginosa. The high level of iron stimulated the synthesis of Psl by reducing rhamnolipid biosynthesis and inhibiting the expression of AmrZ, a repressor of psl genes. Iron-stimulated Psl biosynthesis and biofilm formation held true in mucoid P. aeruginosa strains. Subsequent experiments indicated that iron bound with Psl in vitro and in biofilms, which suggested that Psl fibers functioned as an iron storage channel in P. aeruginosa biofilms. Moreover, among three matrix exopolysaccharides of P. aeruginosa, Psl is the only exopolysaccharide that can bind with both ferrous and ferric ion, yet with higher affinity for ferrous iron. Our data suggest a survival strategy of P. aeruginosa that uses exopolysaccharide to sequester and store iron to stimulate Psl-dependent biofilm formation. IMPORTANCE Pseudomonas aeruginosa is an environmental microorganism which is also an opportunistic pathogen that can cause severe infections in immunocompromised individuals. It is the predominant airway pathogen causing morbidity and mortality in individuals affected by the genetic disease cystic fibrosis (CF). Increased airway iron and biofilm formation have been proposed to be the potential factors involved in the persistence of P. aeruginosa in CF patients. Here, we showed that a high level of iron enhanced the production of the key biofilm matrix exopolysaccharide Psl to stimulate Psl-dependent biofilm formation. Our results not only make the link between biofilm formation and iron concentration in CF, but also could guide the administration or use of iron chelators to interfere with biofilm formation in P. aeruginosa in CF patients. Furthermore, our data also imply a survival strategy of P. aeruginosa under high-iron environmental conditions. PMID:27565622

Characterization of zinc stress response in Cyanobacterium Synechococcus sp. IU 625.

PubMed

Newby, Robert; Lee, Lee H; Perez, Jose L; Tao, Xin; Chu, Tinchun

2017-05-01

The ability of cyanobacteria to survive many environmental stress factors is a testament to their resilience in nature. Of these environmental stress factors, overexposure to zinc is important to study since excessive zinc intake can be a severe hazard. Zinc toxicity in freshwater has been demonstrated to affects organisms such as invertebrates, algae and cyanobacteria. Cyanobacteria which possess increased resistance to zinc have been isolated. It is therefore important to elucidate the mechanism of survival and response to determine what factors allow their survival; as well as any remediation implications they may have. To characterize the effects of zinc in freshwater cyanobacteria, we investigated the response of Synechococcus sp. IU 625 (S. IU 625) over 29days to various concentrations (10, 25, and 50mg/L) of ZnCl 2 . S. IU 625 was shown to be tolerant up to 25mg/L ZnCl 2 exposure, with 10mg/L ZnCl 2 having no outward physiological change and 50mg/L ZnCl 2 proving lethal to the cells. To determine a potential mechanism Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) and RNA-seq analysis were performed on zinc exposed cells. Analysis performed on days 4 and 7 indicated that response is dose-dependent, with 10mg/L ZnCl 2 exhibiting nearly all zinc extracellular, corresponding with upregulation of cation transport response. Whereas the 25mg/L ZnCl 2 exhibited half of total zinc sequestered by the cells, which corresponds with the upregulation of sequestering proteins such as metallothionein and the downregulation of genes involved with ATP synthesis and phycobilisome assembly. These analyses were combined with growth monitoring, microscopy, quantitative polymerase chain reaction (qPCR) and flow cytometry to present a full spectrum of mechanisms behind zinc response in S. IU 625. Copyright © 2017 Elsevier B.V. All rights reserved.

A comprehensive review on green nanomaterials using biological systems: Recent perception and their future applications.

PubMed

Saratale, Rijuta Ganesh; Karuppusamy, Indira; Saratale, Ganesh Dattatraya; Pugazhendhi, Arivalagan; Kumar, Gopalakrishanan; Park, Yooheon; Ghodake, Gajanan S; Bharagava, Ram Naresh; Banu, J Rajesh; Shin, Han Seung

2018-05-19

Over the last few years, nanotechnology is increasingly developing in scientific sector, which has attracted a great deal of interest because of its abundant applications in almost all the areas. In recent times, green nanotechnology is a relative and multidisciplinary field that has emerged as a rapidly developing research area. This is serving as an important technique that spotlight on making the procedure which is clean, safe and in particular environtmentally friendly, in a gap with the currently employed methods such as chemical and physical methods for nanosynthesis. The present review recaps the existing knowledge on various biogenic synthesis methods relying on bacteria, fungi, yeast, algae, viruses and on using biomolecules. The green nanosynthesis refers to the employment of reducing and stabilizing agents from plants and other natural resources, to fabricate nanomaterials. The green synthesis method does not engage the use of exceedingly venomous chemicals or elevated energy inputs during the synthesis. Nanoparticles (NPs) with distinct shapes, sizes and bioactivity can be produced from the variations in the bio-reducing agents employed for nanosynthesis. Hence, this review article summarizes the present information regarding the biological methods which are employed to fabricate greener, safer, and environmentally sustainable nanosynthesis routes. This review mainly highlights the wide-scale fabrication of NPs via green synthesis for biomedical and agricultural applications. Copyright © 2018. Published by Elsevier B.V.

Synthesis, Structural Characterization and Antinociceptive Activities of New Arylated Quinolines via Suzuki-Miyaura Cross Coupling Reaction.

PubMed

Ullah, Malik A; Adeel, Muhammad; Tahir, Muhammad N; Rauf, Abdur; Akram, Muhammad; Hadda, Taibi B; Mabkhot, Yahia N; Muhammad, Naveed; Naseer, Fehmida; Mubarak, Mohammad S

2017-01-01

The quinoline ring system is one of the most commonly encountered heterocycles in medicinal chemistry, due to the pharmaceutical and medicinal uses of derivatives containing this ring. These quinoline-based compounds have remarkable biological activity, as they are employed as antimalarial, antibacterial, antifungal, and antitumor agents. The quinoline nucleus can be synthesized by various traditional methods such as the Skraup reaction, Friedlaender synthesis, Combes quinoline synthesis, Larock quinoline synthesis, among others. The aim of the present work is to synthesize a number of new arylated quninolines having significant antinoceciptive effect through the Suzuki-Miyaura cross coupling reaction using 3- bromoquinoline as a starting material. A number of new quinoline derivatives have been synthesized. Structures of the newly synthesized compounds were confirmed by means of IR, NMR, and mass spectrometry, and by elemental analysis. In addition, the molecular structures of two representative derivatives were determined with the aid of X-ray crystallography. Additionally, the antinociceptive activity of the prepared compounds was evaluated in vivo; results revealed that most of the tested compounds exhibited a dosedependent antinociceptive effect. Prepared compounds were found to exhibit significant antinociceptive activities and could be used as potential analgesic agents. Further work, however, may be required to establish the safety and efficacy of these compounds. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Microplasma-liquid interactions for nanomaterials synthesis

NASA Astrophysics Data System (ADS)

Patel, Jenish; Maguire, Paul; Mariotti, Davide

2012-10-01

Interactions of microplasmas with solid, liquid and/or gas precursors provide new pathways for the synthesis and surface-engineering of nanomaterials. This study is focused on the plasma-induced non-euqilibrium liquid-chemistry (PiLC) as an effective approach to synthesize colloidal metal nanoparticles without using any reducing/capping agents. Highly dispersed gold and silver nanoparticles (NPs) were synthesized in aqueous solutions without any capping agents which explore the opportunities to functionalize the surface of these surfactant-free metal NPs for a better device applications. In particular, various sizes (5 nm to 100 nm) and shapes (e.g. spherical, hexagonal, pentagonal, triangular, etc.) of the gold nanoparticles (AuNPs) were formed with different concentrations of gold precursor. Moreover, conductivity, pH and temperature of the solutions were measured before and after the plasma processing, in order to realize the basic chemistry initiated by plasma in/at liquid surface. Especially, to understand the basic reduction process of AuNPs synthesis by plasma, we measured the presence the of hydrogen peroxide (H2O2) which is believed to be a strong reductant for gold and for the first time we demonstrated experimentally that H2O2 is the key factor that reduces the gold precursor to AuNPs. These investigations create the opportunities to understand how these microplasmas can be effectively explored to other materials synthesis/processing.

Ribozyme-mediated cleavage of c-fos mRNA reduces gene expression of DNA synthesis enzymes and metallothionein.

PubMed Central

Scanlon, K J; Jiao, L; Funato, T; Wang, W; Tone, T; Rossi, J J; Kashani-Sabet, M

1991-01-01

The c-fos gene product Fos has been implicated in many cellular processes, including signal transduction, DNA synthesis, and resistance to antineoplastic agents. A fos ribozyme (catalytic RNA) was designed to evaluate the effects of suppressing Fos protein synthesis on expression of enzymes involved in DNA synthesis, DNA repair, and drug resistance. DNA encoding the fos ribozyme (fosRb) was cloned into the pMAMneo expression plasmid, and the resultant vector was transfected into A2780DDP cells resistant to the chemotherapeutic agent cisplatin. The parental drug-sensitive A2780S cells were transfected with the pMMV vector containing the c-fos gene. Morphological alterations were accompanied by significant changes in pharmacological sensitivity in both c-fos- and fosRb-transfected cells. pMAMneo fosRb transfectants revealed decreased c-fos gene expression, concomitant with reduced thymidylate (dTMP) synthase, DNA polymerase beta, topoisomerase I, and metallothionein IIA mRNAs. In contrast, c-myc expression was elevated after fos ribozyme action. Insertion of a mutant ribozyme, mainly capable of antisense activity, into A2780DDP cells resulted in smaller reductions in c-fos gene expression and in cisplatin resistance than the active ribozyme. These studies establish a role for c-fos in drug resistance and in mediating DNA synthesis and repair processes by modulating expression of genes such as dTMP synthase, DNA polymerase beta, and topoisomerase I. These studies also suggest the utility of ribozymes in the analysis of cellular gene expression. Images PMID:1660142

A Short Review on the Synthetic Strategies of Duocarmycin Analogs that are Powerful DNA Alkylating Agents.

PubMed

Patil, Pravin C; Satam, Vijay; Lee, Moses

2015-01-01

The duocarmycins and CC-1065 are members of a class of DNA minor groove, AT-sequence selective, and adenine-N3 alkylating agents, isolated from Streptomyces sp. that exhibit extremely potent cytotoxicity against the growth of cancer cells grown in culture. Initial synthesis and structural modification of the cyclopropa[c] pyrrolo[3,2-e]indole (CPI) DNA-alkylating motif as well as the indole non-covalent binding region in the 1980s have led to several compounds that entered clinical trials as potential anticancer drugs. However, due to significant systemic toxicity none of the analogs have passed clinical evaluation. As a result, the intensity in the design, synthesis, and development of novel analogs of the duocarmycins has continued. Accordingly, in this review, which covers a period from the 1990s through the present time, the design and synthesis of duocarmycin SA are described along with the synthesis of novel and highly cytotoxic analogs that lack the chiral center. Examples of achiral analogs of duocarmycin SA described in this review include seco-DUMSA (39 and 40), seco-amino-CBI-TMI (13, Centanamycin), and seco-hydroxy-CBI-TMI (14). In addition, another novel class of biologically active duocarmycin SA analogs that contained the seco-iso-cyclopropylfurano[2,3-e]indoline (seco-iso-CFI) and seco-cyclopropyltetrahydrofurano[2,3-f]quinoline (seco-CFQ) DNA alkylating submit was also designed and synthesized. The synthesis of seco-iso-CFI-TMI (10, Tafuramycin A) and seco-CFQ-TMI (11, Tafuramycin B) is included in this review.

Work of community health agents in the Family Health Strategy: meta-synthesis

PubMed Central

Alonso, Carolina Maria do Carmo; Béguin, Pascal Daniel; Duarte, Francisco José de Castro Moura

2018-01-01

ABSTRACT OBJECTIVE To systematize and analyze the evidence from qualitative studies that address the perception of Brazilian Community Health Agents about their work. METHODS This is a systematic review of the meta-synthesis type on the work of community health agents, carried out from the Virtual Health Library using the descriptors “Agente Comunitário de Saúde” and “Trabalho”, in Portuguese. The strategy was constructed by crossing descriptors, using the Boolean operator “AND”, and filtering Brazilian articles, published from 2004 to 2014, which resulted in 129 identified articles. We removed quantitative or quanti-qualitative research articles, essays, debates, literature reviews, reports of experiences, and research that did not include Brazilian Community Health Agents as subjects. Using these criteria, we selected and analyzed 33 studies that allowed us to identify common subjects and differences between them, to group the main conclusions, to classify subjects, and to interpret the content. RESULTS The analysis resulted in three thematic units: characteristics of the work of community health agents, problems related to the work of community health agents, and positive aspects of the work of community health agents. On the characteristics, we could see that the work of the community health agents is permeated by the political and social dimensions of the health work with predominant use of light technologies. The main input is the knowledge that this professional obtains with the contact with families, which is developed with home visits. On the problems in the work of community health agents, we could identify the lack of limits in their attributions, poor conditions, obstacles in the relationship with the community and teams, weak professional training, and bureaucracy. The positive aspects we identified were the recognition of the work by families, resolution, bonding, work with peers, and work close to home. CONCLUSIONS This review provided an overview of the difficulties and positive aspects that are present in the daily work of community health agents. Given this, we have raised two challenges. The first one refers to how public policy makers need to appropriation the research results and the second one refers to the need to invest in studies that are designed to generate solutions for the difficulties faced by community health agents in their work. PMID:29489997

Work of community health agents in the Family Health Strategy: meta-synthesis.

PubMed

Alonso, Carolina Maria do Carmo; Béguin, Pascal Daniel; Duarte, Francisco José de Castro Moura

2018-01-01

OBJECTIVE To systematize and analyze the evidence from qualitative studies that address the perception of Brazilian Community Health Agents about their work. METHODS This is a systematic review of the meta-synthesis type on the work of community health agents, carried out from the Virtual Health Library using the descriptors "Agente Comunitário de Saúde" and "Trabalho", in Portuguese. The strategy was constructed by crossing descriptors, using the Boolean operator "AND", and filtering Brazilian articles, published from 2004 to 2014, which resulted in 129 identified articles. We removed quantitative or quanti-qualitative research articles, essays, debates, literature reviews, reports of experiences, and research that did not include Brazilian Community Health Agents as subjects. Using these criteria, we selected and analyzed 33 studies that allowed us to identify common subjects and differences between them, to group the main conclusions, to classify subjects, and to interpret the content. RESULTS The analysis resulted in three thematic units: characteristics of the work of community health agents, problems related to the work of community health agents, and positive aspects of the work of community health agents. On the characteristics, we could see that the work of the community health agents is permeated by the political and social dimensions of the health work with predominant use of light technologies. The main input is the knowledge that this professional obtains with the contact with families, which is developed with home visits. On the problems in the work of community health agents, we could identify the lack of limits in their attributions, poor conditions, obstacles in the relationship with the community and teams, weak professional training, and bureaucracy. The positive aspects we identified were the recognition of the work by families, resolution, bonding, work with peers, and work close to home. CONCLUSIONS This review provided an overview of the difficulties and positive aspects that are present in the daily work of community health agents. Given this, we have raised two challenges. The first one refers to how public policy makers need to appropriation the research results and the second one refers to the need to invest in studies that are designed to generate solutions for the difficulties faced by community health agents in their work.

In situ synthesis of gold nanoparticles in exponentially-growing layer-by-layer films

PubMed Central

Shen, Liyan; Rapenne, Laetitia; Chaudouet, Patrick; Ji, Jian; Picart, Catherine

2014-01-01

In situ synthesis of inorganic nanoparticles (NPs) in polyelectrolytes multilayers (PEMs) has recently gained much attention. Due to the versatility of their composition, PEMs offer a unique opportunity to synthesize a variety of NPs. So far, mostly cationic precursors have been used and only few studies have investigated the possibility of using amine groups to bind anionic precursors. Here, we use exponentially growing poly(L-lysine)/hyaluronan (PLL/HA) films as a nanoreservoir to bind and sequester aurochlorate (AuCl4−) anions thanks to the large number of free amine groups. The polypeptide-polysaccharide reactive template enabled the formation in a spatially-confined environment of gold NP at a very high yield. The synthesized gold NPs were homogenous and well-dispersed in the nanocomposite. Importantly, there was no particular effect of the film-ending layer (either PLL or HA). The largest particles of ~ 9 nm and the largest amount of gold were obtained at acidic pH of 3. When the pH was increased, smaller and more numerous NPs were synthesized but the total amount of gold was lower. Based on UV-visible spectrometry, FTIR and TEM data, we finally propose a scheme for the mechanism of gold NPs formation, in which several groups of PLL and HA contribute to the binding of gold ions, the nucleation and growth of NPs, and their stabilization in the “bulk” of the film. PMID:22981588

Cytological characteristics and classification of spindle inhibitors according to their effects on segmentation mitoses.

PubMed

Sentein, P; Ates, Y

1978-01-01

The effects of spindle inhibitors and of protein synthesis inhibitors on segmentation mitoses allow us to classify them into six groups : 1. Colchicine type : destruction of the whole achromatic apparatus and centrospheres without storing of dense bodies; 2. Quinoline type : same effect on the achromatic apparatus, but blocked centrospheres with accumulation of dense bodies; 3. Chloralhydrate type : Incomplete destruction of achromatic apparatus, spindle residue which maintains the chromosomes in a star shape, inactive centrospheres sequestered by the reticulum, but without accumulation of dense bodies; 4. Phenylurethane type : Incomplete and reversible action, which leads to easy production of pluripolar mitoses; 5. Carboxylic acid type : dissociation of the spindle, sometimes with blocking of the centrosphere, together with profound chromosome changes without primitive breaks; the intensity and quality of their action is related to the number of carbon atoms in the acid considered; 6. Protein synthesis inhibitor type : (cycloheximide, pederin) characterized by a stop of the nuclear cycle at telo-prophase when the action is sufficient, chromosome abnormalities, sometimes, reduced to strings of beads, and freeing of asters; at weaker concentrations mitosis is possible, but the congression of chromosomes at the equator is abnormal because of functional disturbance of the kinetochores. The nature and grading of these effects, their association (or non - association) to chromosome damage, the soundness of the spindle when only the chromosomes are affected (nitrogen mustard) make this one of the tests which gives the most specific data about the action of antimitotic substances.

Sequestration of the Aβ Peptide Prevents Toxicity and Promotes Degradation In Vivo

PubMed Central

de Barros, Teresa Pereira; van Dijk Härd, Iris; Brorsson, Ann-Christin; Macao, Bertil; Persson, Cecilia; Crowther, Damian C.; Lomas, David A.; Ståhl, Stefan; Dobson, Christopher M.; Härd, Torleif

2010-01-01

Protein aggregation, arising from the failure of the cell to regulate the synthesis or degradation of aggregation-prone proteins, underlies many neurodegenerative disorders. However, the balance between the synthesis, clearance, and assembly of misfolded proteins into neurotoxic aggregates remains poorly understood. Here we study the effects of modulating this balance for the amyloid-beta (Aβ) peptide by using a small engineered binding protein (ZAβ3) that binds with nanomolar affinity to Aβ, completely sequestering the aggregation-prone regions of the peptide and preventing its aggregation. Co-expression of ZAβ3 in the brains of Drosophila melanogaster expressing either Aβ42 or the aggressive familial associated E22G variant of Aβ42 abolishes their neurotoxic effects. Biochemical analysis indicates that monomer Aβ binding results in degradation of the peptide in vivo. Complementary biophysical studies emphasize the dynamic nature of Aβ aggregation and reveal that ZAβ3 not only inhibits the initial association of Aβ monomers into oligomers or fibrils, but also dissociates pre-formed oligomeric aggregates and, although very slowly, amyloid fibrils. Toxic effects of peptide aggregation in vivo can therefore be eliminated by sequestration of hydrophobic regions in monomeric peptides, even when these are extremely aggregation prone. Our studies also underline how a combination of in vivo and in vitro experiments provide mechanistic insight with regard to the relationship between protein aggregation and clearance and show that engineered binding proteins may provide powerful tools with which to address the physiological and pathological consequences of protein aggregation. PMID:20305716

Green Synthesis of Robust, Biocompatible Silver Nanoparticles Using Garlic Extract

PubMed Central

Von White, Gregory; Kerscher, Petra; Brown, Ryan M.; Morella, Jacob D.; McAllister, William; Dean, Delphine; Kitchens, Christopher L.

2012-01-01

This paper details a facile approach for the synthesis of stable and monodisperse silver nanoparticles performed at ambient/low temperature where Allium sativum (garlic) extract functions as the silver salt reducing agent during nanoparticle synthesis as well as the post-synthesis stabilizing ligands. Varying the synthesis conditions provides control of particle size, size-distribution, and kinetics of particle formation. Infrared spectroscopy, energy dispersive x-ray chemical analysis, and high performance liquid chromatography indicated that the carbohydrates present in the garlic extract are the most likely nanoparticle stabilizing chemistry. The synthesized silver nanoparticles also demonstrate potential for biomeical applications, owing to the 1) enhanced stability in biological media, 2) resistance to oxidation by the addition of H2O2, 3) ease and scalability of synthesis, and 4) lack of harsh chemicals required for synthesis. Cytotoxicity assays indicated no decrease in cellular proliferation for vascular smooth muscle cells and 3T3 fibroblasts at a concentration of 25 μg/ml, confirming that garlic extract prepared silver nanoparticles are ideal candidates for future experimentation and implementation into biomedical applications. PMID:24683414

Green Synthesis of Robust, Biocompatible Silver Nanoparticles Using Garlic Extract.

PubMed

Von White, Gregory; Kerscher, Petra; Brown, Ryan M; Morella, Jacob D; McAllister, William; Dean, Delphine; Kitchens, Christopher L

2012-01-01

This paper details a facile approach for the synthesis of stable and monodisperse silver nanoparticles performed at ambient/low temperature where Allium sativum (garlic) extract functions as the silver salt reducing agent during nanoparticle synthesis as well as the post-synthesis stabilizing ligands. Varying the synthesis conditions provides control of particle size, size-distribution, and kinetics of particle formation. Infrared spectroscopy, energy dispersive x-ray chemical analysis, and high performance liquid chromatography indicated that the carbohydrates present in the garlic extract are the most likely nanoparticle stabilizing chemistry. The synthesized silver nanoparticles also demonstrate potential for biomeical applications, owing to the 1) enhanced stability in biological media, 2) resistance to oxidation by the addition of H 2 O 2 , 3) ease and scalability of synthesis, and 4) lack of harsh chemicals required for synthesis. Cytotoxicity assays indicated no decrease in cellular proliferation for vascular smooth muscle cells and 3T3 fibroblasts at a concentration of 25 μg/ml, confirming that garlic extract prepared silver nanoparticles are ideal candidates for future experimentation and implementation into biomedical applications.

Cellular Inclusion Bodies of Mutant Huntingtin Exon 1 Obscure Small Fibrillar Aggregate Species

PubMed Central

Sahl, Steffen J.; Weiss, Lucien E.; Duim, Whitney C.; Frydman, Judith; Moerner, W. E.

2012-01-01

The identities of toxic aggregate species in Huntington's disease pathogenesis remain ambiguous. While polyQ-expanded huntingtin (Htt) is known to accumulate in compact inclusion bodies inside neurons, this is widely thought to be a protective coping response that sequesters misfolded conformations or aggregated states of the mutated protein. To define the spatial distributions of fluorescently-labeled Htt-exon1 species in the cell model PC12m, we employed highly sensitive single-molecule super-resolution fluorescence imaging. In addition to inclusion bodies and the diffuse pool of monomers and oligomers, fibrillar aggregates ~100 nm in diameter and up to ~1–2 µm in length were observed for pathogenic polyQ tracts (46 and 97 repeats) after targeted photo-bleaching of the inclusion bodies. These short structures bear a striking resemblance to fibers described in vitro. Definition of the diverse Htt structures in cells will provide an avenue to link the impact of therapeutic agents to aggregate populations and morphologies. PMID:23193437

Ectromelia virus encodes an anti-apoptotic protein that regulates cell death.

PubMed

Mehta, Ninad; Taylor, John; Quilty, Douglas; Barry, Michele

2015-01-15

Apoptosis serves as a powerful defense against damaged or pathogen-infected cells. Since apoptosis is an effective defense against viral infection, many viruses including poxviruses, encode proteins to prevent or delay apoptosis. Here we show that ectromelia virus, the causative agent of mousepox encodes an anti-apoptotic protein EVM025. Here we demonstrate that expression of functional EVM025 is crucial to prevent apoptosis triggered by virus infection and staurosporine. We demonstrate that the expression of EVM025 prevents the conformational activation of the pro-apoptotic proteins Bak and Bax, allowing the maintenance of mitochondrial membrane integrity upon infection with ECTV. Additionally, EVM025 interacted with intracellular Bak. We were able to demonstrate that EVM025 ability to inhibit Bax activation is a function of its ability to inhibit the activity of an upstream BH3 only protein Bim. Collectively, our data indicates that EVM025 inhibits apoptosis by sequestering Bak and inhibiting the activity of Bak and Bax. Copyright © 2014 Elsevier Inc. All rights reserved.

Proof-of-Concept of the Phytoimmobilization Technology for TNX Outfall Delta: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, D.I.

2001-06-04

A series of proof-of-principle studies was initiated to evaluate the soil remediation technology, phytoimmobilization, for application at the TNX Outfall Delta (TNX OD) operable unit. Phytoimmobilization involves two steps. The first step is entitled phytoextraction, and it takes place mostly during the spring and summer. During this step the plants extract contaminants from the sediment into the roots and then translocate the contaminants to the aboveground plant parts. The second step is referred to as sequestration and it takes place largely during the autumn and winter when annual plants senesce or deciduous trees drop their leaves. This step involves themore » immobilization of the contaminant once it leaches form the fallen leaves into a ''geomat,'' a geotextile embedded with mineral sequestering agents. This final report describes the results to date, including those reported in the status report (Kaplan et al. 2000a), those completed since the report was issued, and the preliminary calculations of the phytoimmobilization effectiveness.« less

The effect of the textile industry dye bath additive EDTMPA on colour removal characteristics by ozone oxidation.

PubMed

Olmez, T; Kabdaşli, I; Tünay, O

2007-01-01

In this study, the effects of the phosphonic acid based sequestering agent EDTMPA used in the textile dye baths on colour and organic matter removal by ozone oxidation was experimentally investigated. Procion Navy HEXL dyestuff that has been commonly used for the reactive dyeing of cellulose fibers was selected as the model component. The organic matter oxidation by ozone was determined to obey the pseudo-first order kinetics as they are treated singly or in combination. COD removal rates obtained from pseudo-first order reaction kinetics showed that oxidation of Navy HEXL alone (0.0947 L/min) was faster than that of EDTMPA (0.0171 L/min) and EDTMPA with dye (0.0155 L/min) at pH 3.0. It was also found that reaction rates of single EDTMPA removal and EDTMPA and dye mixture removal increased as the reaction pH was increased from 3.0 to 10.5.

Human Calprotectin Is an Iron-Sequestering Host-Defense Protein

PubMed Central

Nakashige, Toshiki G.; Zhang, Bo; Krebs, Carsten; Nolan, Elizabeth M.

2015-01-01

Human calprotectin (CP) is a metal-chelating antimicrobial protein of the innate immune response. The current working model states that CP sequesters manganese and zinc from pathogens. We report the discovery that CP chelates iron and deprives bacteria of this essential nutrient. Elemental analysis of CP-treated growth medium establishes that CP reduces the concentrations of manganese, iron, and zinc. Microbial growth studies reveal that iron depletion by CP contributes to the growth inhibition of bacterial pathogens. Biochemical investigations demonstrate that CP coordinates Fe(II) at an unusual hexahistidine motif, and the Mössbauer spectrum of 57Fe(II)-bound CP is consistent with coordination of high-spin Fe(II) at this site (δ = 1.20 mm/s, ΔEQ = 1.78 mm/s). In the presence of Ca(II), CP turns on its iron-sequestering function and exhibits sub-picomolar affinity for Fe(II). Our findings expand the biological coordination chemistry of iron and support a previously unappreciated role for CP in mammalian iron homeostasis. PMID:26302479

Synthesis route and three different core-shell impacts on magnetic characterization of gadolinium oxide-based nanoparticles as new contrast agents for molecular magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Azizian, Gholamreza; Riyahi-Alam, Nader; Haghgoo, Soheila; Moghimi, Hamid Reza; Zohdiaghdam, Reza; Rafiei, Behrooz; Gorji, Ensieh

2012-10-01

Despite its good resolution, magnetic resonance imaging intrinsically has low sensitivity. Recently, contrast agent nanoparticles have been used as sensitivity and contrast enhancer. The aim of this study was to investigate a new controlled synthesis method for gadolinium oxide-based nanoparticle preparation. For this purpose, diethyleneglycol coating of gadolinium oxide (Gd2O3-DEG) was performed using new supervised polyol route, and small particulate gadolinium oxide (SPGO) PEGylation was obtained with methoxy-polyethylene-glycol-silane (550 and 2,000 Da) coatings as SPGO-mPEG-silane550 and 2,000, respectively. Physicochemical characterization and magnetic properties of these three contrast agents in comparison with conventional Gd-DTPA were verified by dynamic light scattering transmission electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma, X-ray diffraction, vibrating sample magnetometer, and the signal intensity and relaxivity measurements were performed using 1.5-T MRI scanner. As a result, the nanoparticle sizes of Gd2O3-DEG, SPGO-mPEG-silane550, and SPGO-mPEG-silane2000 could be reached to 5.9, 51.3, 194.2 nm, respectively. The image signal intensity and longitudinal ( r 1) and transverse relaxivity ( r 2) measurements in different concentrations (0.3 to approximately 2.5 mM), revealed the r 2/ r 1 ratios of 1.13, 0.89, 33.34, and 33.72 for Gd-DTPA, Gd2O3-DEG, SPGO-mPEG-silane550, and SPGO-mPEG-silane2000, respectively. The achievement of new synthesis route of Gd2O3-DEG resulted in lower r 2/ r 1 ratio for Gd2O3-DEG than Gd-DTPA and other previous synthesized methods by this and other groups. The smaller r 2/ r 1 ratios of two PEGylated-SPGO contrast agents in our study in comparison with r 2/ r 1 ratio of previous PEGylation ( r 2/ r 1 = 81.9 for mPEG-silane 6,000 MW) showed that these new three introduced contrast agents could potentially be proper contrast enhancers for cellular and molecular MR imaging.

Deoxypodophyllotoxin: a promising therapeutic agent from herbal medicine.

PubMed

Khaled, Meyada; Jiang, Zhen-Zhou; Zhang, Lu-Yong

2013-08-26

Recently, biologically active compounds isolated from plants used in herbal medicine have been the center of interest. Deoxypodophyllotoxin (DPT), structurally closely related to the lignan podophyllotoxin, is a potent antitumor and anti-inflammatory agent. However, DPT has not been used clinically yet. Also, DPT from natural sources seems to be unavailable. Hence, it is important to establish alternative resources for the production of such lignan; especially that it is used as a precursor for the semi-synthesis of the cytostatic drugs etoposide phosphate and teniposide. The update paper provides an overview of DPT as an effective anticancer natural compound and a leader for cytotoxic drugs synthesis and development in order to highlight the gaps in our knowledge and explore future research needs. The present review covers the literature available from 1877 to 2012. The information was collected via electronic search using Chinese papers and the major scientific databases including PubMed, Sciencedirect, Web of Science and Google Scholar using the keywords. All abstracts and full-text articles reporting database on the history and current status of DPT were gathered and analyzed. Plants containing DPT have played an important role in traditional medicine. In light of the in vitro pharmacological investigations, DPT is a high valuable medicinal agent that has anti-tumor, anti-proliferative, anti-inflammatory and anti-allergic properties. Further, DPT is an important precursor for the cytotoxic aryltetralin lignan, podophyllotoxin, which is used to obtain semisynthetic derivatives like etoposide and teniposide used in cancer therapy. However, most studies have focused on the in vitro data. Therefore, DPT has not been used clinically yet. DPT has emerged as a potent chemical agent from herbal medicine. Therefore, in vivo studies are needed to carry out clinical trials in humans and enable the development of new anti-cancer agents. In addition, DPT from commercial sources seems to be unavailable due to its rarity from natural sources and cumbersome extraction procedures. Hence, it is important to establish alternative, cost-effective and renewable resources, such plant cell cultures and (semi-) synthesis strategies for the production of DPT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Nano Sponges for Drug Delivery and Medicinal Applications

NASA Technical Reports Server (NTRS)

Tour, James M.; Lucente-Schultz, Rebecca; Leonard, Ashley; Kosynkin, Dimitry V.; Price, Brandi Katherine; Hudson, Jared L.; Conyers, Jodie L., Jr.; Moore, Valerie C.; Casscells, S. Ward; Myers, Jeffrey N.;

Host Shifts from Lamiales to Brassicaceae in the Sawfly Genus Athalia

PubMed Central

Opitz, Sebastian E. W.; Boevé, Jean-Luc; Nagy, Zoltán Tamás; Sonet, Gontran; Koch, Frank; Müller, Caroline

2012-01-01

Plant chemistry can be a key driver of host shifts in herbivores. Several species in the sawfly genus Athalia are important economic pests on Brassicaceae, whereas other Athalia species are specialized on Lamiales. These host plants have glucosides in common, which are sequestered by larvae. To disentangle the possible direction of host shifts in this genus, we examined the sequestration specificity and feeding deterrence of iridoid glucosides (IGs) and glucosinolates (GSs) in larvae of five species which either naturally sequester IGs from their hosts within the Plantaginaceae (Lamiales) or GSs from Brassicaceae, respectively. Furthermore, adults were tested for feeding stimulation by a neo-clerodane diterpenoid which occurs in Lamiales. Larvae of the Plantaginaceae-feeders did not sequester artificially administered p-hydroxybenzylGS and were more deterred by GSs than Brassicaceae-feeders were by IGs. In contrast, larvae of Brassicaceae-feeders were able to sequester artificially administered catalpol (IG), which points to an ancestral association with Lamiales. In line with this finding, adults of all tested species were stimulated by the neo-clerodane diterpenoid. Finally, in a phylogenetic tree inferred from genetic marker sequences of 21 Athalia species, the sister species of all remaining 20 Athalia species also turned out to be a Lamiales-feeder. Fundamental physiological pre-adaptations, such as the establishment of a glucoside transporter, and mechanisms to circumvent activation of glucosides by glucosidases are therefore necessary prerequisites for successful host shifts between Lamiales and Brassicaceae. PMID:22485146

Localization of Defensive Chemicals in Two Congeneric Butterflies (Euphydryas, Nymphalidae).

PubMed

Mason, Peri A; Deane Bowers, M

2017-05-01

Many insect species sequester compounds acquired from their host plants for defense against natural enemies. The distribution of these compounds is likely to affect both their efficacy as defenses, and their costs. In this study we examined the distribution of sequestered iridoid glycosides (IGs) in two congeneric species of nymphalid butterfly, Euphydryas anicia and E. phaeton, and found that the pattern of localization of IGs differed between the two species. Although IG concentrations were quite high in the heads of both species, the relative concentrations in wings and abdomens differed substantially. Euphydryas anicia had relatively high IG concentrations in their abdomens and low IG concentrations in their wings, whereas the reverse was true in E. phaeton. We interpret these results in light of two current hypotheses regarding where sequestered chemicals should be localized: that they should be found in wings, which would allow non-lethal sampling by predators; and that their distribution is constrained by the distribution of tissue types to which sequestered compounds bind. We also offer the third hypothesis, that costs of storage may differ among body parts, and that the localization of compounds may reflect a cost-reduction strategy. Results from E. phaeton were consistent with all three of these non-mutually exclusive hypotheses, whereas results from E. anicia were only consistent with the notion that tissue bias among body parts plays a role in IG distribution. The finding that these two congeneric butterflies exhibit different patterns of IG localization suggests that they have been shaped by different selection regimes.

Tartaric acid assisted hydrothermal synthesis of different flower-like ZnO hierarchical architectures with tunable optical and oxygen vacancy-induced photocatalytic properties

NASA Astrophysics Data System (ADS)

Liu, Tingzhi; Li, Yangyang; Zhang, Hao; Wang, Min; Fei, Xiaoyan; Duo, Shuwang; Chen, Ying; Pan, Jian; Wang, Wei

2015-12-01

Different flower-like ZnO hierarchical architectures were prepared by tartaric acid assisted hydrothermal synthesis, especially four flower-like ZnO nanostructures were obtained simultaneously under the same reaction condition. The cauliflower-like ZnO is assembled by spherical shaped nanoparticles, and the chrysanthemum-like and other flower-like ZnO nanostructures are assembled by hexagonal rods/prisms with from planar to semi-pyramid, and to pyramid tips. TA acts as a capping agent and structure-directing agent during the synthesis. All ZnO possess the hexagonal wurtzite structure. The PL spectra can be tuned by changing TA concentration. XRD, PL and Raman spectra confirmed that oxygen vacancies mainly come from the ZnO surface. The flower-like samples of 1:4.5 and 1:3 with the largest aspect ratios have highest photocatalytic performance. They decompose 85% MB within 60 min. Combining PL Gaussian fitting with K, the higher content of oxygen vacancy is, the higher photocatalytic activity is. The enhanced photocatalytic performance is mainly induced by oxygen vacancy of ZnO. The possible formation mechanism, growth and change process of flower-like ZnO were proposed.

Synthesis of Pt/rGO catalysts with two different reducing agents and their methanol electrooxidation activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vu, Thu Ha Thi, E-mail: ptntd2004@yahoo.fr; Tran, Thanh Thuy Thi, E-mail: tranthithanhthuygl@gmail.com; Le, Hong Ngan Thi

2016-01-15

Highlights: • Pt/rGO catalysts were successfully synthesized using either NaBH{sub 4} or ethylene glycol. • Synthesis using NaBH{sub 4} could improve electrocatalytic towards methanol oxidation of Pt/rGO catalyst. • 40%Pt/rGO synthesized using NaBH{sub 4} showed the best electrocatalytic performance. - Abstract: The synthesis processes of Platinum (Pt) on reduced graphene oxide (rGO) catalysts from graphene oxide (GO) using two reducing agents including sodium borohydride and ethylene glycol is reported. Structure and morphology of Pt/rGO catalysts are characterized by X-ray powder diffraction, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrocatalytic methanol oxidation properties of these catalysts are evaluated bymore » cyclic voltammetry and chronoamperometry. The results show that catalyst synthesized using sodium borohydride has a higher metallic Pt content and an improved catalytic performance in comparison to catalyst synthesized using ethylene glycol. Moreover, effect of Pt loading amount on electrocatalytic methanol oxidation performance of catalysts synthesized using sodium borohydride is systematically investigated. The optimal Pt loading amount on graphene is determined to be 40%.« less

One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles.

PubMed

Hussain, Muhammad Ajaz; Shah, Abdullah; Jantan, Ibrahim; Tahir, Muhammad Nawaz; Shah, Muhammad Raza; Ahmed, Riaz; Bukhari, Syed Nasir Abbas

2014-12-03

Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. UV-vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies showed spherical Ag NPs in the size regime of ~50-70 nm. Face centered cubic lattice of Ag NPs was confirmed by powder X-ray diffraction (PXRD). FT-IR spectroscopy confirmed that dextran not only acts as reducing agent but also functionalizes the surfaces of Ag NPs to make very stable dispersions. Moreover, on drying, the solution of dextran stabilized Ag NPs resulted in the formation of thin films which were found stable over months with no change in the plasmon band of pristine Ag NPs. The antimicrobial assay of the as synthesized Ag NPs showed remarkable activity. Being significantly active against microbes, the Ag NPs can be explored for antimicrobial medical devices.

Antimicrobial Resistance and the Alternative Resources with Special Emphasis on Plant-Based Antimicrobials—A Review

PubMed Central

Chandra, Harish; Bishnoi, Parul; Yadav, Archana; Patni, Babita; Mishra, Abhay Prakash; Nautiyal, Anant Ram

2017-01-01

Indiscriminate and irrational use of antibiotics has created an unprecedented challenge for human civilization due to microbe’s development of antimicrobial resistance. It is difficult to treat bacterial infection due to bacteria’s ability to develop resistance against antimicrobial agents. Antimicrobial agents are categorized according to their mechanism of action, i.e., interference with cell wall synthesis, DNA and RNA synthesis, lysis of the bacterial membrane, inhibition of protein synthesis, inhibition of metabolic pathways, etc. Bacteria may become resistant by antibiotic inactivation, target modification, efflux pump and plasmidic efflux. Currently, the clinically available treatment is not effective against the antibiotic resistance developed by some bacterial species. However, plant-based antimicrobials have immense potential to combat bacterial, fungal, protozoal and viral diseases without any known side effects. Such plant metabolites include quinines, alkaloids, lectins, polypeptides, flavones, flavonoids, flavonols, coumarin, terpenoids, essential oils and tannins. The present review focuses on antibiotic resistance, the resistance mechanism in bacteria against antibiotics and the role of plant-active secondary metabolites against microorganisms, which might be useful as an alternative and effective strategy to break the resistance among microbes. PMID:28394295

Synthesis of Gold Nanoparticles Using Leaf Extract of Ziziphus zizyphus and their Antimicrobial Activity

PubMed Central

Akkam, Yazan; Al-Batayneh, Khalid M.; Abo Alrob, Osama; Alkilany, Alaaldin M.; Benamara, Mourad

2018-01-01

(1) Background: There is a growing need for the development of new methods for the synthesis of nanoparticles. The interest in such particles has raised concerns about the environmental safety of their production methods; (2) Objectives: The current methods of nanoparticle production are often expensive and employ chemicals that are potentially harmful to the environment, which calls for the development of “greener” protocols. Herein we describe the synthesis of gold nanoparticles (AuNPs) using plant extracts, which offers an alternative, efficient, inexpensive, and environmentally friendly method to produce well-defined geometries of nanoparticles; (3) Methods: The phytochemicals present in the aqueous leaf extract acted as an effective reducing agent. The generated AuNPs were characterized by Transmission electron microscopy (TEM), Scanning electron microscope (SEM), and Atomic Force microscopy (AFM), X-ray diffraction (XRD), UV-visible spectroscopy, energy dispersive X-ray (EDX), and thermogravimetric analyses (TGA); (4) Results and Conclusions: The prepared nanoparticles were found to be biocompatible and exhibited no antimicrobial or antifungal effect, deeming the particles safe for various applications in nanomedicine. TGA analysis revealed that biomolecules, which were present in the plant extract, capped the nanoparticles and acted as stabilizing agents. PMID:29562669

Unlocking the chemotherapeutic potential of beta-aminovinyl ketones and related compounds.

PubMed

Gaber, Hatem M; Bagley, Mark C

2009-07-01

The role of beta-aminovinyl ketones as synthetic intermediates has been well categorised, but recent developments have shown an interesting array of applications and new chemotherapeutic potential, both in the preparation of biologically active heterocycles and as pharmacophores in their own right.Medicinal chemists are accustomed to using the products of Knoevenagel-type condensations as auxiliaries for the synthesis of N-containing heteroaromatic compounds. One such example of these chemical building blocks are beta-aminovinyl ketones-valuable synthetic intermediates that have been used in the preparation of pyridines, pyrimidines, pyrazoles, and many other heterocyclic motifs. This review highlights their recent use in the synthesis of biologically active targets as part of drug discovery programmes and in natural product synthesis. However, it is becoming increasingly evident that the enaminone motif may serve as a therapeutic pharmacophore in its own right. This review highlights the range of biological responses that beta-aminovinyl ketones elicit, including as antitumour, antibacterial, and anticonvulsant agents. Thus, with a broad spectrum of biological properties and as versatile chemical intermediates, it is clear that beta-aminovinyl ketones offer great potential in the search for new chemotherapeutic agents.

Green synthesis of Ag nanoparticles using plant metabolites

NASA Astrophysics Data System (ADS)

Filippi, Antonio; Mattiello, Alessandro; Musetti, Rita; Petrussa, Elisa; Braidot, Enrico; Marchiol, Luca

2017-08-01

Nano-biotechnology is one of the most promising areas in modern nanoscience and technology. In this emerging area of research, nanoparticles (NPs) play an important role since the large-scale production and huge numbers of utilization. Gold and silver nanoparticles are among the most extensively studied nanomaterials, since they show high stability and low chemical reactivity in comparison to other metals. They are commonly synthesized using toxic chemical reducing agents able to reduce metal ions into uncharged NPs and/or high energy supplied procedures. The most commonly used method for the synthesis of NPs requires toxic chemicals like N,N-dimethyl formamide (DMF) or trisodium citrate, but recently a green technique, based on natural reducing agents, has been suggested to substitute the nature-unfriendly chemical methods. Many scientific works put in evidence the efficacy of plant extracts to reduce metal salts into the respective NPs, but this process lacks a clear control of NPs shapes and dimensions, since many different metabolites present into the extracts could participate to the process. This paper aims to clarify the reducing action of single pure natural compounds usually present in plant tissues and to obtain a stable and reproducible protocol for NPs synthesis.

Rapid biological synthesis of platinum nanoparticles using Ocimum sanctum for water electrolysis applications.

PubMed

Soundarrajan, C; Sankari, A; Dhandapani, P; Maruthamuthu, S; Ravichandran, S; Sozhan, G; Palaniswamy, N

2012-06-01

The leaf extract of Ocimum sanctum was used as a reducing agent for the synthesis of platinum nanoparticles from an aqueous chloroplatinic acid (H(2)PtCl(6)·6H(2)O). A greater conversion of platinum ions to nanoparticles was achieved by employing a tulsi leaf broth with a reaction temperature of 100 °C. Energy-dispersive absorption X-ray spectroscopy confirmed the platinum particles as major constituent in the reduction process. It is evident from scanning electron microscopy that the reduced platinum particles were found as aggregates with irregular shape. Fourier-transform infrared spectroscopy revealed that the compounds such as ascorbic acid, gallic acid, terpenoids, certain proteins and amino acids act as reducing agents for platinum ions reduction. X-ray diffraction spectroscopy suggested the associated forms of platinum with other molecules and the average particle size of platinum nanoparticle was 23 nm, calculated using Scherer equation. The reduced platinum showed similar hydrogen evolution potential and catalytic activity like pure platinum using linear scan voltammetry. This environmentally friendly method of biological platinum nanoparticles production increases the rates of synthesis faster which can potentially be used in water electrolysis applications.

Antibacterial potential of silver nanoparticles synthesized using Madhuca longifolia flower extract as a green resource.

PubMed

Patil, Maheshkumar Prakash; Singh, Rahul Dheerendra; Koli, Prashant Bhimrao; Patil, Kalpesh Tumadu; Jagdale, Bapu Sonu; Tipare, Anuja Rajesh; Kim, Gun-Do

2018-05-25

The green and one-step synthesis of silver nanoparticles (AgNPs) has been proposed as simple and ecofriendly. In the present study, a flower extract of Madhuca longifolia was used for the reduction of silver nitrate into AgNPs, with phytochemicals from the flower extract as a reducing and stabilizing agents. The synthesized AgNPs were spherical and oval shaped and about 30-50 nm sizes. The appearance of a brown color in the reaction mixture is a primary indication of AgNPs formation, and it was confirmed by observing UV-visible spectroscopy peak at 436 nm. The Energy Dispersive X-ray spectra and X-ray diffraction analysis results together confirm that the synthesized nanoparticles contain silver and silver chloride nanoparticles. The Zeta potential analysis indicates presence of negative charges on synthesized AgNPs. The FT-IR study represents involvement of functional groups in AgNPs synthesis. Synthesized AgNPs shows potential antibacterial activity against Gram-positive and Gram-negative pathogens. M. longifolia flower is a good source for AgNPs synthesis and synthesized AgNPs are applicable as antibacterial agent in therapeutics. Copyright © 2018 Elsevier Ltd. All rights reserved.

ENVIRONMENTAL ENGINEERING AND ENDOCRINE DISRUPTING CHEMICALS

EPA Science Inventory

Endocrine disruptors are a class of chemicals of growing interest to the environmental community. USEPA's Risk Assessment Forum defined an endocrine disrupting chemical (EDC) as "an exogenous agent that interferes with the synthesis, secretion, transport, binding, action, or elim...

Enantiomerically Pure Acetals in Organic Synthesis: Resolutions and Diastereoselective Alkylations of Alpha-Hydroxy Esters

DTIC Science & Technology

1990-01-01

sensitivity of the alkylating agent to the reaction conditions. In either case , a decision was made to use 5-iodo-2- methyl -l-pentene as the alkylating ...agent, and the reaction conditions. In most cases the diastereomeric products of the alkylation were also separated by column chromatography. This...equatorially substituted product. Oxidation of the alcohol to the ketone followed by treatment with an alkyl Grignard reagent gave only the product which

Design of Monoamine Reuptake Inhibitors: SSRIs, SNRIs and NRIs

NASA Astrophysics Data System (ADS)

Whitlock, Gavin A.; Andrews, Mark D.; Brown, Alan D.; Fish, Paul V.; Stobie, Alan; Wakenhut, Florian

This review will detail the medicinal chemistry involved in the design, synthesis and discovery of selective serotonin, noradrenaline reuptake inhibitors and dual serotonin/noradrenaline reuptake inhibitors. In particular, this review will focus exclusively on series and compounds which have been disclosed within the medicinal chemistry literature between January 2000 and June 2008. Background information on previously disclosed clinical agents, such as atomoxetine, milnacipran and reboxetine, is included for comparison purposes with more recently disclosed agents.

Dicationic ionic liquid mediated fabrication of Au@Pt nanoparticles supported on reduced graphene oxide with highly catalytic activity for oxygen reduction and hydrogen evolution

NASA Astrophysics Data System (ADS)

Shi, Ya-Cheng; Chen, Sai-Sai; Feng, Jiu-Ju; Lin, Xiao-Xiao; Wang, Weiping; Wang, Ai-Jun

2018-05-01

Ionic liquids as templates or directing agents have attracted great attention for shaping-modulated synthesis of advanced nanomaterials. In this work, reduced graphene oxide supported uniform core-shell Au@Pt nanoparticles (Au@Pt NPs/rGO) were fabricated by a simple one-pot aqueous approach, using N-methylimidazolium-based dicationic ionic liquid (1,1-bis(3-methylimadazoilum-1-yl)butylene bromide, [C4(Mim)2]2Br) as the shape-directing agent. The morphology evolution, structural information and formation mechanism of Au@Pt NPs anchored on rGO were investigated by a series of characterization techniques. The obtained nanocomposites displayed superior electrocatalytic features toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) compared with commercial Pt/C catalyst. This approach provides a novel route for facile synthesis of nanocatalysts in fuel cells.

Substituted 3-((Z)-2-(4-nitrophenyl)-2-(1H-tetrazol-5-yl) vinyl)-4H-chromen-4-ones as novel anti-MRSA agents: synthesis, SAR, and in-vitro assessment.

PubMed

Diwakar, Santosh D; Bhagwat, Sachin S; Shingare, Murlidhar S; Gill, Charansing H

2008-08-15

In search for a new antibacterial agent with improved antimicrobial spectrum and potency, we designed and synthesized a series of novel 3-((Z)-2-(4-nitrophenyl)-2-(1H-tetrazol-5-yl) vinyl)-4H-chromen-4-ones 7a-h by convergent synthesis approach. All the synthesized compounds were assayed for their in-vitro antibacterial activities against gram-negative and gram-positive bacteria. The preliminary structure-activity relationship, to elucidate the essential structure requirements for the antimicrobial activity that results into anti-MRSA (methicillin-resistant S. aureus) potential, has been described. Amongst the synthesized compounds 7d, 7e, 7f and 7h were found to possess activity against methicillin-resistant S. aureus in addition to the activity against other bacterial strains such as E. faecalis, S. pneumoniae, and E. coli.

Synthesis of the spiroacetal-containing anti-Helicobacter pylori agents CJ-12,954 and CJ-13,014.

PubMed

Brimble, Margaret A; Bryant, Christina J

2006-11-21

The first synthesis of the spiroacetal-containing anti-Helicobacter pylori agents ent-CJ-12,954 and ent-CJ-13,014 is reported based on the union of a heterocycle-activated spiroacetal-containing sulfone fragment with a phthalide-containing aldehyde fragment; comparison of the 1H and 13C NMR data, optical rotations and HPLC retention times of the synthetic compounds (3S,2"S,5"S,7"S)-(1a) and (3S,2"S,5"R,7"S)-(2a) and the (3R)-diastereomers (3R,2"S,5"S,7"S)-(1b) and (3R,2"S,5"R,7"S)- (2b) with the naturally occurring compounds established that the synthetic isomers (1a) and (2a) were in fact enantiomeric to the natural products CJ-12,954 and CJ-13,014.

Synthesis of Some Benzofuran Derivatives Containing Pyrimidine Moiety as Potent Antimicrobial Agents.

PubMed

Venkatesh, Talavara; Bodke, Yadav Dasharathrao; Joy, Muthipeedika Nibin; Dhananjaya, Bhadrapura Lakkappa; Venkataraman, Sivaramakrishnan

2018-01-01

In this investigation, the synthesis of 2-substituted pyrimidines by the reaction of benzofuran chalcones (3a-d) with urea, thiourea and guanidine hydrochloride was reported. The structures of title compounds (4a-d), (5a-d) and (6a-d) were established on the basis of analytical and spectral data. The synthesized compounds were screened for antimicrobial activity and molecular docking studies. Some of the compounds displayed excellent antimicrobial activity. The molecular docking analysis revealed that compounds 5a and 5c with the lowest binding energy in comparison to others suggesting its potential as best inhibitor of GluN-6-P. Consequently, it is confirmed from the above analysis that the compounds 5a and 5c might serve as a useful backbone scaffold for rational design, adaptation and investigation of more active analogs as potential broad spectrum antimicrobial agents.

Synthesis and pharmacokinetics of valopicitabine (NM283), an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine.

PubMed

Pierra, Claire; Amador, Agnès; Benzaria, Samira; Cretton-Scott, Erika; D'Amours, Marc; Mao, John; Mathieu, Steven; Moussa, Adel; Bridges, Edward G; Standring, David N; Sommadossi, Jean-Pierre; Storer, Richard; Gosselin, Gilles

2006-11-02

In our search for new therapeutic agents against chronic hepatitis C, a ribonucleoside analogue, 2'-C-methylcytidine, was discovered to be a potent and selective inhibitor in cell culture of a number of RNA viruses, including the pestivirus bovine viral diarrhea virus, a surrogate model for hepatitis C virus (HCV), and three flaviviruses, namely, yellow fever virus, West Nile virus, and dengue-2 virus. However, pharmacokinetic studies revealed that 2'-C-methylcytidine suffers from a low oral bioavailability. To overcome this limitation, we have synthesized the 3'-O-l-valinyl ester derivative (dihydrochloride form, valopicitabine, NM283) of 2'-C-methylcytidine. We detail herein for the first time the chemical synthesis and physicochemical characteristics of this anti-HCV prodrug candidate, as well as a comparative study of its pharmacokinetic parameters with those of its parent nucleoside analogue, 2'-C-methylcytidine.

Solvothermal synthesis of N-doped graphene supported PtCo nanodendrites with highly catalytic activity for 4-nitrophenol reduction

NASA Astrophysics Data System (ADS)

Zhang, Xiao-Fang; Zhu, Xiao-Yan; Feng, Jiu-Ju; Wang, Ai-Jun

2018-01-01

A simple solvothermal method was developed to prepare N-doped reduced graphene oxide supported homogeneous PtCo nanodendrites (PtCo NDs/N-rGO), where ethylene glycol (EG) served as the reducing agent and the solvent, and linagliptin as the structure-directing and stabilizing agent for PtCo NDs and dopant for rGO, respectively. Controlled researches showed that the dosage of linagliptin and the ratios of the two metal precursors were important in the current synthesis. The PtCo NDs/N-rGO nanocomposite exhibited higher catalytic activity towards the reduction of 4-nitrophnol (4-NP) in contrast with the referenced Pt1Co3 NCs/N-rGO, Pt3Co1 NCs/N-rGO and commercial Pt/C catalysts. More importantly, the constructed catalyst exhibited the superior stability without sacrificing the catalytic activity, showing great prospect for the reduction of 4-NP in practice.

High-level production of C-11-carboxyl-labeled amino acids. [For use in tumor and pancreatic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washburn, L. C.; Sun, T. T.; Byrd, B. L.

Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two othersmore » for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period.« less

Porous metal oxide particles and their methods of synthesis

DOEpatents

Chen, Fanglin; Liu, Qiang

2013-03-12

Methods are generally disclosed for synthesis of porous particles from a solution formed from a leaving agent, a surfactant, and a soluble metal salt in a solvent. The surfactant congregates to form a nanoparticle core such that the metal salt forms about the nanoparticle core to form a plurality of nanoparticles. The solution is heated such that the leaving agent forms gas bubbles in the solution, and the plurality of nanoparticles congregate about the gas bubbles to form a porous particle. The porous particles are also generally disclosed and can include a particle shell formed about a core to define an average diameter from about 0.5 .mu.m to about 50 .mu.m. The particle shell can be formed from a plurality of nanoparticles having an average diameter of from about 1 nm to about 50 nm and defined by a metal salt formed about a surfactant core.

3-methyl-2-phenyl-1-substituted-indole derivatives as indomethacin analogs: design, synthesis and biological evaluation as potential anti-inflammatory and analgesic agents.

PubMed

Abdellatif, Khaled R A; Lamie, Phoebe F; Omar, Hany A

2016-01-01

In a new group of 3-methyl-2-phenyl-1-substituted-indole derivatives (10a-f), the indomethacin analogs were prepared via the Fisher indole synthesis reaction of propiophenone with appropriately substituted phenylhydrazine hydrochloride. This is followed by the insertion of the appropriate benzyl or benzoyl fragment. All the synthesized compounds were evaluated for their anti-inflammatory (in vitro and in vivo) and analgesic activities. The methanesulphonyl derivatives 10d, e and f showed the highest anti-inflammatory (in vitro and in vivo) and analgesic activities. In addition, molecular docking studies were performed on compounds 10a-f and the results were in agreement with that obtained from the in vitro COX inhibition assays. The significant anti-inflammatory and analgesic activities exhibited by 10d and 10e warrant continued preclinical development as potential anti-inflammatory and analgesic agents.

Facile Synthesis of Efficient Antibacterial Agent as CoFe₂O₄/Ag Composite Material Against Both Gram-Negative Escherichia coli and Gram-Positive Bacillus subtilis Bacteria.

PubMed

Gankhuyag, Sukhbayar; Lee, Kyoung; Bae, Dong Sik

2018-09-01

We have suggested that a facile synthesis of CoFe2O4/Ag composite material as an antibacterial agent for substitution of a chlorination agent for microbial infected wastewater treatment. The CoFe2O4/Ag was synthesized by an impregnation method in assistance with trisodium citrate as a reducing agent. The as-prepared uncalcined CoFe2O4 (CFG), calcined CoFe2O4 (CFG600), and calcined CoFe2O4/Ag (CFG600/Ag) composites were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM) and Energy Dispersive X-ray (EDX) techniques. Antibacterial activities were also determined in liquid culture by measuring the minimum inhibitory concentrations (MIC) against Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) bacteria in vitro. Results showed that CFG600/Ag composites had an excellent antibacterial activity in comparison with CFG and CFG600 composites. The CFG600/Ag composites have completely inhibited the growth of both E. coli and B. subtilis bacteria from concentrations of more than 0.25 mg/ml. Furthermore, the FE-SEM study demonstrated the physical damage of bacteria when treated with CFG600/Ag composite material at a concentration of 0.10 mg/ml.

Development and Testing of an In Vitro Assay for Screening of Potential Therapeutic Agents against Na Channel Neurotoxins

DTIC Science & Technology

1987-02-03

or by synthesis , the search almost certainly would have failed (3). Fortunately, the accumulated knowledge of sodium channel pharmacology allows the...distinct sodium channel domains. These studies were made possible by the synthesis of a tritiated analog of BTX, batrachotoxinin-A benzoate (BTX-B), of...elaborated upon. Creveling et al. (11) found that the local anesthetic lidocaine ethiodide was 10 times more potent at displacing specifically bound [3H]BTX-B

Design and synthesis of novel N-benzylidenesulfonohydrazide inhibitors of MurC and MurD as potential antibacterial agents.

PubMed

Frlan, Rok; Kovac, Andreja; Blanot, Didier; Gobec, Stanislav; Pecar, Slavko; Obreza, Ales

2008-01-11

A series of novel N-benzylidenesulfonohydrazide compounds were designed and synthesized as inhibitors of UDP-N-acetylmuramic acid: L-alanine ligase (MurC) and UDP-N-acetylmuramoyl-L-alanine: D-glutamate ligase (MurD) from E. coli, involved in the biosynthesis of bacterial cell-walls. Some compounds possessed inhibitory activity against both enzymes with IC(50) values as low as 30 microM. In addition, a new, one-pot synthesis of amidobenzaldehydes is reported.

A library synthesis of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester derivatives as anti-tumor agents.

PubMed

Hayakawa, Ichiro; Shioya, Rieko; Agatsuma, Toshinori; Furukawa, Hidehiko; Naruto, Shunji; Sugano, Yuichi

2004-09-06

As a result of a hit-to-lead program using a technique of solution-phase parallel synthesis, a highly potent (2,4-dimethoxyphenyl)-[6-(3-fluorophenyl)-4-hydroxy-3-methylbenzofuran-2-yl]methanone (15b) was synthesized as an optimized derivative of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester (1), which was discovered as a screening hit from small-molecule libraries and exhibited selective cytotoxicity against a tumorigenic cell line.

Sol-gel synthesis and characterization of SiO{sub 2}/PEG hybrid materials containing quercetin as implants with antioxidant properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Catauro, Michelina; Bollino, Flavia; Gloria, Antonio

2016-05-18

In the present work, Silica/Polyethylene glycol (PEG) hybrid nanocomposites containing an antioxidant agent, the quercetin, were synthesized via sol-gel to be used as implants with antioxidant properties. Fourier transform infrared (FT-IR) analysis proved that a modification of both polymer and quercetin occurs due to synthesis process. Scanning electron microscope (SEM) showed that the proposed materials were hybrid nanocomposites. The bioactivity was ascertained by soaking the samples in a simulated body fluid (SBF).

Prostate Cancer Evaluation: Design, Synthesis, and Evaluation of Novel Enzyme-Activated Proton MRI Contrast Agents

DTIC Science & Technology

2007-10-01

colored plates: ALL DTIC reproductions will be in black and white. 14. ABSTRACT The lacZ gene encoding E . coli beta-gal has already been...interaction, lacZ gene encoding E . coli β-gal has already been recognized as the most commonly used reporter system.[34] However, the well-established...Figure 7 Moreover, we are deeply encouraged by the success on the synthesis of the target molecule M7, as shown in Figure 8. f e d cba OH N

2-Aminoquinazolin-4(3H)-one as an Organocatalyst for the Synthesis of Tertiary Amines.

PubMed

Thakur, Maheshwar S; Nayal, Onkar S; Upadhyay, Rahul; Kumar, Neeraj; Maurya, Sushil K

2018-03-02

The potential of 2-aminoquinazolin-4(3H)-one as an organocatalyst for the activation of aldehydes via noncovalent interaction for the synthesis of tertiary amines using formic acid as a reducing agent is reported for the first time. The developed protocol demonstrated a dilated substrate scope for aromatic and aliphatic amines with aromatic and aliphatic aldehydes. Furthermore, the current method was also fruitful for the derivatization of ciprofloxacin and its derivative in good to excellent yields.

To Investigate the Therapeutic Efforts of the COX-2 Inhibitor NS-398 as a Single Agent, and in Combination with Vitamin D, in Vitro and in Vivo

DTIC Science & Technology

2008-01-01

by immunoelectron microscopy. The Journal Of Biological Chemistry 1998;273:9886-93. 29. Iniguez M, Rodriguez A, Volpert O, Fresno M, Redondo J...controlled by local hypoxia that induces the synthesis of angio- genic factors that can activate signal pathways and transcrip- tion for endothelial...Helmberg,A. and Karin,M. (1995) Immunosuppression by glucocorticoids: inhibition of NF-kappa B activity through induction of I kappa B synthesis . Science

Synthesis of a new family of acyclic nucleoside phosphonates, analogues of TPases transition states.

PubMed

Dayde, Bénédicte; Benzaria, Samira; Pierra, Claire; Gosselin, Gilles; Surleraux, Dominique; Volle, Jean-Noël; Pirat, Jean-Luc; Virieux, David

2012-05-07

A 6-step procedure was developed for the synthesis of a new family of acyclic nucleoside phosphonates (ANPs), "PHEEPA" [(2-pyrimidinyl-2-(2-hydroxyethoxy)ethyl)phosphonic acids] in overall yields ranging from 4.5% to 32%. These compounds, which possess on one side a hydroxy function and on the other side a phosphonate group, can be considered either as potential antiviral agents or as transition state analogues of nucleoside phosphorylases such as thymidine phosphorylase.

Multiagent intelligent systems

NASA Astrophysics Data System (ADS)

Krause, Lee S.; Dean, Christopher; Lehman, Lynn A.

2003-09-01

This paper will discuss a simulation approach based upon a family of agent-based models. As the demands placed upon simulation technology by such applications as Effects Based Operations (EBO), evaluations of indicators and warnings surrounding homeland defense and commercial demands such financial risk management current single thread based simulations will continue to show serious deficiencies. The types of "what if" analysis required to support these types of applications, demand rapidly re-configurable approaches capable of aggregating large models incorporating multiple viewpoints. The use of agent technology promises to provide a broad spectrum of models incorporating differing viewpoints through a synthesis of a collection of models. Each model would provide estimates to the overall scenario based upon their particular measure or aspect. An agent framework, denoted as the "family" would provide a common ontology in support of differing aspects of the scenario. This approach permits the future of modeling to change from viewing the problem as a single thread simulation, to take into account multiple viewpoints from different models. Even as models are updated or replaced the agent approach permits rapid inclusion in new or modified simulations. In this approach a variety of low and high-resolution information and its synthesis requires a family of models. Each agent "publishes" its support for a given measure and each model provides their own estimates on the scenario based upon their particular measure or aspect. If more than one agent provides the same measure (e.g. cognitive) then the results from these agents are combined to form an aggregate measure response. The objective would be to inform and help calibrate a qualitative model, rather than merely to present highly aggregated statistical information. As each result is processed, the next action can then be determined. This is done by a top-level decision system that communicates to the family at the ontology level without any specific understanding of the processes (or model) behind each agent. The increasingly complex demands upon simulation for the necessity to incorporate the breadth and depth of influencing factors makes a family of agent based models a promising solution. This paper will discuss that solution with syntax and semantics necessary to support the approach.

Tetramethylenedisulfotetramine: pest control gone awry.

PubMed

Shakarjian, Michael P; Laukova, Marcela; Velíšková, Jana; Stanton, Patric K; Heck, Diane E; Velíšek, Libor

2016-08-01

Incidences of pesticide poisonings are a significant cause of morbidity and mortality worldwide. The seizure-inducing rodenticide tetramethylenedisulfotetramine is one of the most toxic of these agents. Although banned, it has been responsible for thousands of accidental, intentional, and mass poisonings in mainland China and elsewhere. An optimal regimen for treatment of poisoning has not been established. Its facile synthesis from easily obtained starting materials, extreme potency, and lack of odor, color, or taste make it a potential chemical threat agent. This review describes the toxicologic properties of this agent, more recent advances in our understanding of its properties, and recommendations for future research. © 2016 New York Academy of Sciences.

Green synthesis of anisotropic gold nanoparticles for photothermal therapy of cancer.

PubMed

Fazal, Sajid; Jayasree, Aswathy; Sasidharan, Sisini; Koyakutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

2014-06-11

Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm(2) proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy.

Co-Encapsulating the Fusogenic Peptide INF7 and Molecular Imaging Probes in Liposomes Increases Intracellular Signal and Probe Retention

PubMed Central

Martin, Erik W.; Li, Changqing; Lu, Wuyuan; Kao, Joseph P. Y.

2015-01-01

Liposomes are promising vehicles to deliver diagnostic and therapeutic agents to cells in vivo. After uptake into cells by endocytosis, liposomes are degraded in the endolysosomal system. Consequently, the encapsulated cargo molecules frequently remain sequestered in endosomal compartments; this limits their usefulness in many applications (e.g. gene delivery). To overcome this, various fusogenic peptides have been developed to facilitate delivery of liposomally-encapsulated molecules into the cytosol. One such peptide is the pH-sensitive influenza-derived peptide INF7. Liposomal delivery of imaging agents is an attractive approach for enabling cell imaging and cell tracking in vivo, but can be hampered by inadequate intracellular accumulation and retention of probes caused by exocytosis (and possible degradation) of endosome-entrapped probes. Such signal loss could be minimized by facilitating escape of probe molecules from endolysosomal compartments into the cytosol. We investigated the ability of co-encapsulated INF7 to release liposomally-delivered rhodamine fluorophores into the cytosol after endosomal acidification/maturation. We co-encapsulated INF7 and fluorescent rhodamine derivatives having vastly different transport properties to show that after endocytosis by CV1 cells, the INF7 peptide is activated by acidic endosomal pH and facilitates efficient release of the fluorescent tracers into the cytosol. Furthermore, we show that INF7-facilitated escape from endosomes markedly enhanced retention of tracers that cannot be actively extruded from the cytosol. Minimizing loss of intracellular probes improves cellular imaging by increasing the signal-to-noise ratio of images and lengthening the time window that imaging can be performed. In particular, this will enhance in vivo electron paramagnetic resonance imaging, an emergent magnetic resonance imaging modality requires exogenous paramagnetic imaging agents and is highly promising for cellular and molecular imaging. PMID:25816348

Design, Synthesis and Pharmacological Evaluation of Novel Vanadium-Containing Complexes as Antidiabetic Agents

PubMed Central

Fedorova, Elena V.; Buryakina, Anna V.; Zakharov, Alexey V.; Filimonov, Dmitry A.; Lagunin, Alexey A.; Poroikov, Vladimir V.

2014-01-01

Based on the data about structure and antidiabetic activity of twenty seven vanadium and zinc coordination complexes collected from literature we developed QSAR models using the GUSAR program. These QSAR models were applied to 10 novel vanadium coordination complexes designed in silico in order to predict their hypoglycemic action. The five most promising substances with predicted potent hypoglycemic action were selected for chemical synthesis and pharmacological evaluation. The selected coordination vanadium complexes were synthesized and tested in vitro and in vivo for their hypoglycemic activities and acute rat toxicity. Estimation of acute rat toxicity of these five vanadium complexes was performed using a freely available web-resource (http://way2drug.com/GUSAR/acutoxpredict.html). It has shown that the selected compounds belong to the class of moderate toxic pharmaceutical agents, according to the scale of Hodge and Sterner. Comparison with the predicted data has demonstrated a reasonable correspondence between the experimental and predicted values of hypoglycemic activity and toxicity. Bis{tert-butyl[amino(imino)methyl]carbamato}oxovanadium (IV) and sodium(2,2′-Bipyridyl)oxo-diperoxovanadate(V) octahydrate were identified as the most potent hypoglycemic agents among the synthesized compounds. PMID:25057899

Graphene Oxide from Carbon Rod Waste

NASA Astrophysics Data System (ADS)

Rahmawati, F.; Prasasti, B. L. W.; Mudjijono, M.

2018-03-01

Carbon rods extracted from Zn-C primary battery waste was used as raw material for graphene oxide (GO) synthesis. The synthesis used a modified Hummers method by providing potassium permanganate-sulfuric acid as the oxidizing agent. XRD analysis confirms a significant change between the graphite waste pattern and the produced graphene oxide pattern. A major peak at 2θ 27 ° which present in the graphite waste pattern is disappeared after it converts to the product, as well as a broad peak under 25 ° referring the presence of amorphous carbon. A broad peak at low angle of 12.02 ° dominantly present in the prepared GO pattern as a characteristic peak of GO. Meanwhile, some small peaks at 2θ of 17.76 °, 28.58 °, and 37.28 ° confirming the presence of manganese oxide which was used as oxidizing agent. A sharp peak at 1700 – 1500 cm-1 in the FT-IR spectrum indicates the presence of –C=O group, and at 1600 cm-1 refers to –C=C group. It confirms that this research has produced the targeted GO. Even though, the purity is need to be enhanced by removing the rest of oxidizing agent that still exist in the material.