Modeling the intermolecular interactions: molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide.

PubMed

Karabulut, Sedat; Namli, Hilmi; Kurtaran, Raif; Yildirim, Leyla Tatar; Leszczynski, Jerzy

2014-03-01

The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. Copyright © 2013 Elsevier Inc. All rights reserved.

Retinoids induce differentiation and downregulate telomerase activity and N-Myc to increase sensitivity to flavonoids for apoptosis in human malignant neuroblastoma SH-SY5Y cells.

PubMed

Das, Arabinda; Banik, Naren L; Ray, Swapan K

2009-03-01

Human malignant neuroblastoma is characterized by poor differentiation and uncontrolled proliferation of immature neuroblasts. Retinoids such as all-trans-retinoic acid (ATRA), 13-cis-retinoic acid (13-CRA), and N-(4-hydroxyphenyl) retinamide (4-HPR) at low doses are capable of inducing differentiation, while flavonoids such as (-)-epigallocatechin-3-gallate (EGCG) and genistein (GST) at relatively high dose can induce apoptosis. We used combination of retinoid and flavonoid for controlling growth of malignant neuroblastoma SH-SY5Y cells. Cells were treated with a retinoid (1 microM ATRA, 1 microM 13-CRA, or 0.5 microM 4-HPR) for 7 days and then with a flavonoid (25 microM EGCG or 25 microM GST) for 24 h. Treatment of cells with a low dose of a retinoid for 7 days induced neuronal differentiation with downregulation of telomerase activity and N-Myc but overexpression of neurofilament protein (NFP) and subsequent treatment with a relatively high dose of a flavonoid for 24 h increased apoptosis in the differentiated cells. Besides, retinoids reduced the levels of inflammatory and angiogenic factors. Apoptosis was associated with increases in intracellular free [Ca2+], Bax expression, cytochrome c release from mitochondria and activities of calpain and caspases. Decreases in expression of calpastatin (endogenous calpain inhibitor) and baculovirus inhibitor-of-apoptosis repeat containing (BIRC) proteins (endogenous caspase inhibitors) favored apoptosis. Treatment of SH-SY5Y cells with EGCG activated caspase-8, indicating induction of the receptor-mediated pathway of apoptosis. Based on our observation, we conclude that combination of a retinoid and a flavonoid worked synergistically for controlling the malignant growth of human neuroblastoma cells.

Synergistic efficacy of a novel combination therapy controls growth of Bcl-x(L) bountiful neuroblastoma cells by increasing differentiation and apoptosis.

PubMed

Mohan, Nishant; Banik, Naren L; Ray, Swapan K

2011-11-01

Neuroblastoma is the most prevalent extracranial solid tumor mainly in pediatric patients. We explored the efficacy of the combination of 2[(3-[2,3-dichlorophenoxy]propyl)amino]ethanol (2,3-DCPE, a small molecule inhibitor of the anti-apoptotic protein Bcl-x(L)) and N-(4-hydroxyphenyl) retinamide (4-HPR, a synthetic retinoid) in inducing differentiation and apoptosis in human malignant neuroblastoma cells. Immunofluorescence confocal microscopy and flow cytometry showed that the highest level of Bcl-x(L) expression occurred in SK-N-DZ cells followed by SH-SY5Y and IMR-32 cells. Combination of 20 μM 2,3-DCPE and 1 μM 4-HPR acted synergistically in decreasing viability of SK-N-DZ and SH-SY5Y cells. In situ methylene blue staining and protein gel blotting showed the efficacy of this combination of drugs in inducing neuronal differentiation morphologically and also biochemically with upregulation of the neuronal markers such as neurofilament protein (NFP) and neuron specific enolase (NSE) and downregulation of the differentiation inhibiting molecules such as N-Myc and Notch-1 in SK-N-DZ and SH-SY5Y cells. Annexin V-FITC/PI staining showed the synergistic action of this combination therapy in increasing apoptosis in both cell lines. Protein gel blotting manifested that combination therapy increased apoptosis with downregulation of the anti-apoptotic proteins Bcl-x(L), Bcl-2 and Mcl-1 and upregulation of the pro-apoptotic proteins Bax, p53, Puma (p53 upregulated modulator of apoptosis), and Noxa, ultimately causing activation of caspase-3. In conclusion, our results appeared highly encouraging in advocating the use of 2,3-DCPE and 4-HPR as a novel combination therapy for increasing both differentiation and apoptosis in human malignant neuroblastoma cells having Bcl-x(L) overexpression.

Influence of chlorine or fluorine substitution on the estrogenic properties of 1-alkyl-2,3,5-tris(4-hydroxyphenyl)-1H-pyrroles.

PubMed

Schäfer, Anja; Wellner, Anja; Strauss, Martin; Schäfer, Andreas; Wolber, Gerhard; Gust, Ronald

2012-11-26

In continuation of our previous work, several 1-alkyl-2,3,5-tris(4-hydroxyphenyl)aryl-1H-pyrroles with chlorine or fluorine substituents in the aryl residues were synthesized and tested for estrogen receptor (ER) binding at isolated ERα/ERβ receptors (HAP assay) and in transactivation assays using ERα-positive MCF-7/2a as well as U2-OS/ERα and U2-OS/ERβ cells. In the competition experiment at ERα the compounds displayed very high relative binding affinities of up to 37% (determined for 8m) but with restricted subtype selectivity (e.g., ERα/ERβ (8m) = 9). The highest estrogenic potency in ERα-positive MCF-7/2a cells was determined for 2,3,5-tris(2-fluoro-4-hydroxyphenyl)-1-propyl-1H-pyrrole 8m (EC(50) = 23 nM), while in U2-OS/ERα cells 2-(2-fluoro-4-hydroxyphenyl)-3,5-bis(4-hydroxyphenyl)-1-propyl-1H-pyrrole 8b (EC(50) = 0.12 nM) was the most potent agonist, only 30-fold less active than estradiol (E2, EC(50) = 0.004 nM). In U2-OS/ERβ cells for all pyrroles no transactivation could be observed, which indicates that they are selective ERα agonists in cellular systems.

Computational study of the binding mechanism between farnesoid X receptor α and antagonist N-benzyl-N-(3-(tertbutyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino) benzamide.

PubMed

Du, Juan; Qiu, Miaoxue; Guo, Lizhong; Yao, Xiaojun

2018-05-02

Farnesoid X receptor α (FXRα) is a bile acid-activated transcription factor, which plays important roles in the regulation of multiple metabolic processes. Development of FXR antagonist has revealed great potential for the treatment of metabolic disorders. The compound N-Benzyl-N-(3-(tertbutyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino). Benzamide (NDB) was recently determined as a selective antagonist of FXRα, while the detailed interaction mechanism is not well understood. In this study, the combined computational methods including molecular dynamics simulations, binding free energy calculation, and principal component analysis were utilized to investigate the effect of NDB on the dynamics behaviors and dimerization of FXRα The binding free energy calculation indicated that the protein dimerization increases NDB affinity and the binding of NDB also stabilizes the interaction between two subunits of FXRα. Further decomposition of the overall binding free energies into individual residues identifies several residues significant for NDB binding, including Leu291, Met294, Ala295, His298, Met332, Ser336, Ala452, and Leu455. It also suggests that the interactions of L289(A)-W458(B), W458(A)-L289(B), R459(A)-N461(B), and N461(A)-R459(B) are important for the dimer stabilization. This study provides a molecular basis for the understanding of binding mechanism between antagonist NDB and FXRα and valuable information for the novel FXR modulators design for the treatment of metabolic syndrome.

Anti-tumor effects of retinoids combined with trastuzumab or tamoxifen in breast cancer cells: induction of apoptosis by retinoid/trastuzumab combinations.

PubMed

Koay, Debbie C; Zerillo, Cynthia; Narayan, Murli; Harris, Lyndsay N; DiGiovanna, Michael P

2010-01-01

HER2 and estrogen receptor (ER) are important in breast cancer and are therapeutic targets of trastuzumab (Herceptin) and tamoxifen, respectively. Retinoids inhibit breast cancer growth, and modulate signaling by HER2 and ER. We hypothesized that treatment with retinoids and simultaneous targeting of HER2 and/or ER may have enhanced anti-tumor effects. The effects of retinoids combined with trastuzumab or tamoxifen were examined in two human breast cancer cell lines in culture, BT474 and SKBR3. Assays of proliferation, apoptosis, differentiation, cell cycle distribution, and receptor signaling were performed. In HER2-overexpressing/ER-positive BT474 cells, combining all-trans retinoic acid (atRA) with tamoxifen or trastuzumab synergistically inhibited cell growth, and altered cell differentiation and cell cycle. Only atRA/trastuzumab-containing combinations induced apoptosis. BT474 and HER2-overexpressing/ER-negative SKBR3 cells were treated with a panel of retinoids (atRA, 9-cis-retinoic acid, 13-cis-retinoic acid, or N-(4-hydroxyphenyl) retinamide (fenretinide) (4-HPR)) combined with trastuzumab. In BT474 cells, none of the single agents except 4-HPR induced apoptosis, but again combinations of each retinoid with trastuzumab did induce apoptosis. In contrast, the single retinoid agents did cause apoptosis in SKBR3 cells; this was only modestly enhanced by addition of trastuzumab. The retinoid drug combinations altered signaling by HER2 and ER. Retinoids were inactive in trastuzumab-resistant BT474 cells. Combining retinoids with trastuzumab maximally inhibits cell growth and induces apoptosis in trastuzumab-sensitive cells. Treatment with such combinations may have benefit for breast cancer patients.

Synthesis and evaluation of 2-halogenated-1,1-bis(4-hydroxyphenyl)-2-(3-hydroxyphenyl)-ethylenes as potential estrogen receptor-targeted radiodiagnostic and radiotherapeutic agents.

PubMed

Hanson, Robert N; Tongcharoensirikul, Pakamas; Barnsley, Kelton; Ondrechen, Mary Jo; Hughes, Alun; DeSombre, Eugene R

2015-04-01

A series of three 1,1-bis(4-hydroxyphenyl)-2-(3-hydroxyphenyl)-ethylene derivatives was prepared and evaluated as potential estrogen receptor imaging agents. The compounds display high binding affinity compared to estradiol, with the 2-iodo and 2-bromo-derivatives expressing higher affinity than the parent 2-nonhalogenated derivative. Evaluation in immature female rats also indicate that the compounds were all full estrogenic agonists with potencies in the same order of activity (I∼Br>H). Computational analysis of the interactions between the ligands and ERα-LBD demonstrated positive contribution of halide to binding properties. In preparation for studies using the radiohalogenated analogs, the corresponding protected 2-(tributylstannyl) derivative was prepared and converted to the corresponding 2-iodo-product. Copyright © 2015 Elsevier Inc. All rights reserved.

The HPr(Ser) Kinase of Streptococcus salivarius: Purification, Properties, and Cloning of the hprK Gene

PubMed Central

Brochu, Denis; Vadeboncoeur, Christian

1999-01-01

In gram-positive bacteria, HPr, a protein of the phosphoenolpyruvate:sugar phosphotransferase system, is phosphorylated on a serine residue at position 46 by an ATP-dependent protein kinase. The HPr(Ser) kinase of Streptococcus salivarius ATCC 25975 was purified, and the encoding gene (hprK) was cloned by using a nucleotide probe designed from the N-terminal amino acid sequence. The predicted amino acid sequence of the S. salivarius enzyme showed 45% identity with the Bacillus subtilis enzyme, the conserved residues being located mainly in the C-terminal half of the protein. The predicted hprK gene product has a molecular mass of 34,440 Da and a pI of 5.6. These values agree well with those found experimentally by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, molecular sieve chromatography in the presence of guanidine hydrochloride, and chromatofocusing using the purified protein. The native protein migrates on a Superdex 200 HR column as a 330,000-Da protein, suggesting that the HPr(Ser) kinase is a decamer. The enzyme requires Mg2+ for activity and functions optimally at pH 7.5. Unlike the enzyme from other gram-positive bacteria, the HPr(Ser) kinase from S. salivarius is not stimulated by FDP or other glycolytic intermediates. The enzyme is inhibited by inorganic phosphate, and its Kms for HPr and ATP are 31 μM and 1 mM, respectively. PMID:9922231

Effects of 4-Hydroxyphenyl 4-Isoprooxyphenylsulfone (BPSIP) Exposure on Reproduction and Endocrine System of Zebrafish.

PubMed

Lee, Jiyun; Park, Na-Youn; Kho, Younglim; Ji, Kyunghee

2018-02-06

The compound 4-hydroxyphenyl 4-isoprooxyphenylsulfone (BPSIP), a derivative of bisphenol S (BPS), has been detected in thermal paper and human urine samples; however, its potential effects on the endocrine system are largely unknown. The present study was conducted to determine the adverse effects of BPSIP on egg production, relative organ weights, plasma levels of sex hormones, and transcription of genes related to the hypothalamus-pituitary-gonad (HPG) axis in zebrafish (Danio rerio). In male fish, the gonadosomatic index was significantly decreased at concentrations of 5 and 50 μg/L BPSIP. The estrogenic (increase in the 17β-estradiol/testosterone [E2/T] ratio) and antiandrogenic (decrease in T) effects were observed in fish exposed to BPSIP and males were more sensitive to the adverse effects than females. The changes in sex hormones were supported by the regulation of genes along the HPG axis, such as cyp19, 17βhsd, and cyp17 transcripts. Although the effective concentration for endocrine disruption was greater than that of BPS, the actions of BPSIP on the steroidogenic pathway were similar to the effects of BPS exposure.

Photosystem II-inhibitors play a limited role in sweet corn response to 4-hydroxyphenyl pyruvate dioxygenase-inhibiting herbicides

USDA-ARS?s Scientific Manuscript database

Postemergence (POST) application of 4-hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors in combination with a photosystem II (PSII) inhibitor, such as atrazine, is common practice in sweet corn production. Given the sensitivity of sweet corn to HPPD-inhibiting herbicides, the objective of this wo...

Modification of sphingolipid metabolism by tamoxifen and N-desmethyltamoxifen in acute myelogenous leukemia – Impact on enzyme activity and response to cytotoxics

PubMed Central

Morad, Samy A. F.; Tan, Su-Fern; Feith, David J.; Kester, Mark; Claxton, David F.; Loughran, Thomas P.; Barth, Brian M.; Fox, Todd E.; Cabot, Myles C.

2015-01-01

The triphenylethylene antiestrogen, tamoxifen, can be an effective inhibitor of sphingolipid metabolism. This off-target activity makes tamoxifen an interesting ancillary for boosting the apoptosis-inducing properties of ceramide, a sphingolipid with valuable tumor censoring activity. Here we show for the first time that tamoxifen and metabolite, N –desmethyltamoxifen (DMT) block ceramide glycosylation and inhibit ceramide hydrolysis (by acid ceramidase, AC) in human acute myelogenous leukemia (AML) cell lines and in AML cells derived from patients. Tamoxifen (1-10 μM) inhibition of AC in AML cells was accompanied by decreases in AC protein expression. Tamoxifen also depressed expression and activity of sphingosine kinase 1 (SphK1), the enzyme catalyzing production of mitogenic sphingosine 1-phosphate (S1-P). Results from mass spectroscopy showed that tamoxifen and DMT, i ) increased the levels of endogenous C16:0- and C24:1 ceramide molecular species, ii) nearly totally halted production of respective glucosylceramide (GC) molecular species, iii ) drastically reduced levels of sphingosine ( to 9% of control), and iv ) reduced levels of S1-P by 85%, in vincristine-resistant HL-60/VCR cells. Co-administration of tamoxifen with either N-(4-hydroxyphenyl)retinamide (4-HPR), a ceramide-generating retinoid, or a cell-deliverable form of ceramide, C6-ceramide, resulted in marked decreases in HL-60/VCR cell viability that far exceeded single agent potency. Combination treatments resulted in synergistic apoptotic cell death as gauged by increased Annexin V binding and DNA fragmentation and activation of caspase-3. These results show the versatility of adjuvant triphenylethylene with ceramide-centric therapies for magnifying therapeutic potential in AML. Such drug regimens could serve as effective strategies, even in the multidrug resistant setting. PMID:25769964

Phase II study of oral capsular 4-hydroxyphenylretinamide (4-HPR/fenretinide) in pediatric patients with refractory or recurrent neuroblastoma: a report from the Children's Oncology Group.

PubMed

Villablanca, Judith G; London, Wendy B; Naranjo, Arlene; McGrady, Patrick; Ames, Matthew M; Reid, Joel M; McGovern, Renee M; Buhrow, Sarah A; Jackson, Hollie; Stranzinger, Enno; Kitchen, Brenda J; Sondel, Paul M; Parisi, Marguerite T; Shulkin, Barry; Yanik, Gregory A; Cohn, Susan L; Reynolds, C Patrick

2011-11-01

To determine the response rate to oral capsular fenretinide in children with recurrent or biopsy proven refractory high-risk neuroblastoma. Patients received 7 days of fenretinide: 2,475 mg/m(2)/d divided TID (<18 years) or 1,800 mg/m(2)/d divided BID (≥18 years) every 21 days for a maximum of 30 courses. Patients with stable or responding disease after course 30 could request additional compassionate courses. Best response by course 8 was evaluated in stratum 1 (measurable disease on CT/MRI ± bone marrow and/or MIBG avid sites) and stratum 2 (bone marrow and/or MIBG avid sites only). Sixty-two eligible patients, median age 5 years (range 0.6-19.9), were treated in stratum 1 (n = 38) and stratum 2 (n = 24). One partial response (PR) was seen in stratum 2 (n = 24 evaluable). No responses were seen in stratum 1 (n = 35 evaluable). Prolonged stable disease (SD) was seen in 7 patients in stratum 1 and 6 patients in stratum 2 for 4 to 45+ (median 15) courses. Median time to progression was 40 days (range 17-506) for stratum 1 and 48 days (range 17-892) for stratum 2. Mean 4-HPR steady-state trough plasma concentrations were 7.25 μmol/L (coefficient of variation 40-56%) at day 7 course 1. Toxicities were mild and reversible. Although neither stratum met protocol criteria for efficacy, 1 PR + 13 prolonged SD occurred in 14/59 (24%) of evaluable patients. Low bioavailability may have limited fenretinide activity. Novel fenretinide formulations with improved bioavailability are currently in pediatric phase I studies. ©2011 AACR

Liquid chromatography-tandem mass spectrometry analysis of 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine in cooked meats.

PubMed

Busquets, R; Puignou, L; Galceran, M T; Wakabayashi, K; Skog, K

2007-10-31

Several cooked meats such as beef (fried, coated-fried), pork (fried, coated-fried), and chicken (fried, griddled, coated-fried, roasted) were analyzed for the heterocyclic amine 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5- b]pyridine (4'-OH-PhIP) not commonly determined in food and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). The highest content of 4'-OH-PhIP was found in fried and griddled chicken breast, the concentration being 43.7 and 13.4 ng/g, respectively, whereas the corresponding PhIP concentrations were 19.2 and 5.8 ng/g. The estimated concentration of both pyridines in fried pork loin, in fried pork sausages, and in coated-fried chicken was below 2.5 ng/g. In the rest of the samples, 4'-OH-PhIP was not detected. The analyses were performed by solid-phase extraction and LC-MS/MS. The fragmentation of 4'-OH-PhIP in an ion trap mass analyzer was studied in order to provide information for the identification of 4'-OH-PhIP. Additionally, the effect of red wine marinades on the formation of 4'-OH-PhIP in fried chicken was examined, finding a notable reduction (69%) in the amine's occurrence.

Infectious salmon anaemia virus (ISAV) in Chilean Atlantic salmon (Salmo salar) aquaculture: emergence of low pathogenic ISAV-HPR0 and re-emergence of virulent ISAV-HPR∆: HPR3 and HPR14.

PubMed

Godoy, Marcos G; Kibenge, Molly J T; Suarez, Rudy; Lazo, Eduardo; Heisinger, Alejandro; Aguinaga, Javier; Bravo, Diego; Mendoza, Julio; Llegues, Katerina O; Avendaño-Herrera, Rubén; Vera, Cristian; Mardones, Fernando; Kibenge, Frederick S B

2013-11-23

Infectious salmon anaemia (ISA) is a serious disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. ISA is caused by virulent ISAV strains with deletions in a highly polymorphic region (HPR) of the hemagglutinin-esterase (HE) protein (designated virulent ISAV-HPR∆). This study shows the historic dynamics of ISAV-HPR∆ and ISAV-HPR0 in Chile, the genetic relationship among ISAV-HPR0 reported worldwide and between ISAV-HPR0 and ISAV-HPR∆ in Chile, and reports the 2013 ISA outbreak in Chile. The first ISA outbreak in Chile occurred from mid-June 2007 to 2010 and involved the virulent ISAV-HPR7b, which was then replaced by a low pathogenic ISAV-HPR0 variant. We analyzed this variant in 66 laboratory-confirmed ISAV-HPR0 cases in Chile in comparison to virulent ISAV-HPR∆ that caused two new ISA outbreaks in April 2013. Multiple alignment and phylogenetic analysis of HE sequences from all ISAV-HPR0 viruses allowed us to identify three genomic clusters, which correlated with three residue patterns of ISAV-HPR0 (360PST362, 360PAN362 and 360PAT362) in HPR. The virus responsible for the 2013 ISAV-HPR∆ cases in Chile belonged to ISAV-HPR3 and ISAV-HPR14, and in phylogenetic analyses, both clustered with the ISAV-HPR0 found in Chile. The ISAV-HPR14 had the ISAV-HPR0 residue pattern 360PAT362, which is the only type of ISAV-HPR0 variant found in Chile. This suggested to us that the 2013 ISAV-HPR∆ re-emerged from ISAV-HPR0 that is enzootic in Chilean salmon aquaculture and were not new introductions of virulent ISAV-HPR∆ to Chile. The clinical presentations and diagnostic evidence of the 2013 ISA cases indicated a mixed infection of ISAV with the ectoparasite Caligus rogercresseyi and the bacterium Piscirickettsia salmonis, which underscores the need for active ISAV surveillance in areas where ISAV-HPR0 is enzootic, to ensure early detection and control of new ISA outbreaks, as

Infectious salmon anaemia virus (ISAV) in Chilean Atlantic salmon (Salmo salar) aquaculture: emergence of low pathogenic ISAV-HPR0 and re-emergence of virulent ISAV-HPR∆: HPR3 and HPR14

PubMed Central

2013-01-01

Abstact Infectious salmon anaemia (ISA) is a serious disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), which belongs to the genus Isavirus, family Orthomyxoviridae. ISA is caused by virulent ISAV strains with deletions in a highly polymorphic region (HPR) of the hemagglutinin-esterase (HE) protein (designated virulent ISAV-HPR∆). This study shows the historic dynamics of ISAV-HPR∆ and ISAV-HPR0 in Chile, the genetic relationship among ISAV-HPR0 reported worldwide and between ISAV-HPR0 and ISAV-HPR∆ in Chile, and reports the 2013 ISA outbreak in Chile. The first ISA outbreak in Chile occurred from mid-June 2007 to 2010 and involved the virulent ISAV-HPR7b, which was then replaced by a low pathogenic ISAV-HPR0 variant. We analyzed this variant in 66 laboratory-confirmed ISAV-HPR0 cases in Chile in comparison to virulent ISAV-HPR∆ that caused two new ISA outbreaks in April 2013. Multiple alignment and phylogenetic analysis of HE sequences from all ISAV-HPR0 viruses allowed us to identify three genomic clusters, which correlated with three residue patterns of ISAV-HPR0 (360PST362, 360PAN362 and 360PAT362) in HPR. The virus responsible for the 2013 ISAV-HPR∆ cases in Chile belonged to ISAV-HPR3 and ISAV-HPR14, and in phylogenetic analyses, both clustered with the ISAV-HPR0 found in Chile. The ISAV-HPR14 had the ISAV-HPR0 residue pattern 360PAT362, which is the only type of ISAV-HPR0 variant found in Chile. This suggested to us that the 2013 ISAV-HPR∆ re-emerged from ISAV-HPR0 that is enzootic in Chilean salmon aquaculture and were not new introductions of virulent ISAV-HPR∆ to Chile. The clinical presentations and diagnostic evidence of the 2013 ISA cases indicated a mixed infection of ISAV with the ectoparasite Caligus rogercresseyi and the bacterium Piscirickettsia salmonis, which underscores the need for active ISAV surveillance in areas where ISAV-HPR0 is enzootic, to ensure early detection and control of new ISA

The retinamide VNLG-152 inhibits f-AR/AR-V7 and MNK-eIF4E signaling pathways to suppress EMT and castration-resistant prostate cancer xenograft growth.

PubMed

Ramamurthy, Vidya P; Ramalingam, Senthilmurugan; Gediya, Lalji K; Njar, Vincent C O

2018-03-01

VNLG-152 is a novel retinamide (NR) shown to suppress growth and progression of genetically diverse prostate cancer cells via inhibition of androgen receptor signaling and eukaryotic initiation factor 4E (eIF4E) translational machinery. Herein, we report therapeutic effects of VNLG-152 on castration-resistant prostate cancer (CRPC) growth and metastatic phenotype in a CRPC tumor xenograft model. Administration of VNLG-152 significantly and dose-dependently suppressed the growth of aggressive CWR22Rv1 tumors by 63.4% and 76.3% at 10 and 20 mg·kg -1 bw, respectively (P < 0.0001), vs. vehicle with no host toxicity. Strikingly, the expression of full-length androgen receptor (f-AR)/androgen receptor splice variant-7 (AR-V7), mitogen-activated protein kinase-interacting kinases 1 and 2 (MNK1/2), phosphorylated eIF4E and their associated target proteins, including prostate-specific antigen, cyclin D1 and Bcl-2, were strongly decreased in VNLG-152-treated tumors signifying inhibition of f-AR/AR-V7 and MNK-eIF4E signaling in VNLG-152-treated CWR22Rv1 tumors as observed in vitro. VNLG-152 also suppressed the epithelial to mesenchymal transition in CWR22Rv1 tumors as evidenced by repression of N-cadherin, β-catenin, claudin, Slug, Snail, Twist, vimentin and matrix metalloproteinases (MMP-2 and MMP-9) with upsurge in E-cadherin. These results highlight the promising use of VNLG-152 in CRPC therapy and justify its further development towards clinical trials. © 2018 Federation of European Biochemical Societies.

2-Diazo-1-(4-hydroxyphenyl)ethanone: A Versatile Photochemical and Synthetic Reagenta

PubMed Central

Senadheera, Sanjeewa N.; Evans, Anthony S.; Toscano, John P.; Givens, Richard S.

2014-01-01

α-Diazo arylketones are well-known substrates for Wolff rearrangement to phenylacetic acids through a ketene intermediate by either thermal or photochemical activation. Likewise, α-substituted p-hydroxyphenacyl (pHP) esters are substrates for photo-Favorskii rerrangements to phenylacetic acids by a different pathway that purportedly involves a cyclopropanone intermediate. In this paper, we show that the photolysis of a series of α-diazo-p-hydroxyacetophenones and p-hydroxyphenacyl (pHP) α-esters both generate the identical rearranged phenylacetates as major products. Since α-diazo-p-hydroxyacetophenone (1a, pHP N2) contains all the necessary functionalities for either Wolff or Favorskii rearrangement, we were prompted to probe this intriguing mechanistic dichotomy under conditions favorable to the photo-Favorskii reangement, i.e., photolysis in hydroxylic media. An investigation of the mechanism for conversion of 1a to p-hydroxyphenyl acetic acid (4a) using time-resolved infrared (TRIR) spectroscopy clearly demonstrates the formation of a ketene intermediate that is subsequently trapped by solvent or nucleophiles. The photoreaction of 1a is quenched by oxygen and sensitized by triplet sensitizers and the quantum yields for 1a–c range from 0.19 to a robust 0.25. The lifetime of the triplet, determined by Stern-Volmer quenching, is 15 ns with a rate for appearance of 4a of k = 7,1 × 106 s−1 in aq. acetonitrile (1:1 v:v). These studies establish that the primary rearrangement pathway for 1a involves ketene formation in accordance with the photo-Wolff rearrangement. Furthermore we have also demonstrated the synthetic utility of 1a as an esterification and etherification reagent with a variety of substituted α-diazo-p-hydroxyacetophenones, using them as synthons for efficiently coupling it to acids and phenols to produce pHP protect substrates. PMID:24305682

2-Diazo-1-(4-hydroxyphenyl)ethanone: a versatile photochemical and synthetic reagent.

PubMed

Senadheera, Sanjeewa N; Evans, Anthony S; Toscano, John P; Givens, Richard S

2014-02-01

α-Diazo arylketones are well-known substrates for Wolff rearrangement to phenylacetic acids through a ketene intermediate by either thermal or photochemical activation. Likewise, α-substituted p-hydroxyphenacyl (pHP) esters are substrates for photo-Favorskii rearrangements to phenylacetic acids by a different pathway that purportedly involves a cyclopropanone intermediate. In this paper, we show that the photolysis of a series of α-diazo-p-hydroxyacetophenones and p-hydroxyphenacyl (pHP) α-esters both generate the identical rearranged phenylacetates as major products. Since α-diazo-p-hydroxyacetophenone (1a, pHP N2) contains all the necessary functionalities for either Wolff or Favorskii rearrangement, we were prompted to probe this intriguing mechanistic dichotomy under conditions favorable to the photo-Favorskii rearrangement, i.e., photolysis in hydroxylic media. An investigation of the mechanism for conversion of 1a to p-hydroxyphenyl acetic acid (4a) using time-resolved infrared (TRIR) spectroscopy clearly demonstrates the formation of a ketene intermediate that is subsequently trapped by solvent or nucleophiles. The photoreaction of 1a is quenched by oxygen and sensitized by triplet sensitizers and the quantum yields for 1a-c range from 0.19 to a robust 0.25. The lifetime of the triplet, determined by Stern-Volmer quenching, is 31 ns with a rate for appearance of 4a of k = 7.1 × 10(6) s(-1) in aq. acetonitrile (1 : 1 v : v). These studies establish that the primary rearrangement pathway for 1a involves ketene formation in accordance with the photo-Wolff rearrangement. Furthermore we have also demonstrated the synthetic utility of 1a as an esterification and etherification reagent with a variety of substituted α-diazo-p-hydroxyacetophenones, using them as synthons for efficiently coupling it to acids and phenols to produce pHP protect substrates.

Crystallographic identification of an unexpected by-product in an Ullman's reaction toward biphenyls: 1-(4-hexyloxy-3-hydroxyphenyl)ethanone.

PubMed

Manzano, Veronica E; Baggio, Ricardo; Cukiernik, Fabio D

2015-11-01

The synthesis of 3,3'-diacetoxy-4,4'-bis(hexyloxy)biphenyl following the nickel-modified Ullmann reaction yielded a by-product which was identified successfully by crystallographic analysis as 1-(4-hexyloxy-3-hydroxyphenyl)ethanone, C14H20O3. This unexpected nonbiphenyl by-product exhibited IR, (1)H NMR, (13)C NMR and COSY (correlation spectroscopy) spectra fully consistent with the proposed structure. The compound crystallized in the orthorombic Pbca space group, with two independent formula units in the asymmetric unit (one of which was slightly disordered), and showed a supramolecular architecture in which molecules linked by hydroxy-ethanone O-H···O interactions are organized in columns separated by the aliphatic tails.

Regio- and Stereospecific Conversion of 4-Alkylphenols by the Covalent Flavoprotein Vanillyl-Alcohol Oxidase

PubMed Central

van den Heuvel, Robert H. H.; Fraaije, Marco W.; Laane, Colja; van Berkel, Willem J. H.

1998-01-01

The regio- and stereospecific conversion of prochiral 4-alkylphenols by the covalent flavoprotein vanillyl-alcohol oxidase was investigated. The enzyme was active, with 4-alkylphenols bearing aliphatic side chains of up to seven carbon atoms. Optimal catalytic efficiency occurred with 4-ethylphenol and 4-n-propylphenols. These short-chain 4-alkylphenols are stereoselectively hydroxylated to the corresponding (R)-1-(4′-hydroxyphenyl)alcohols (F. P. Drijfhout, M. W. Fraaije, H. Jongejan, W. J. H. van Berkel, and M. C. R. Franssen, Biotechnol. Bioeng. 59:171–177, 1998). (S)-1-(4′-Hydroxyphenyl)ethanol was found to be a far better substrate than (R)-1-(4′-hydroxyphenyl)ethanol, explaining why during the enzymatic conversion of 4-ethylphenol nearly no 4-hydroxyacetophenone is formed. Medium-chain 4-alkylphenols were exclusively converted by vanillyl-alcohol oxidase to the corresponding 1-(4′-hydroxyphenyl)alkenes. The relative cis-trans stereochemistry of these reactions was strongly dependent on the nature of the alkyl side chain. The enzymatic conversion of 4-sec-butylphenol resulted in two (4′-hydroxyphenyl)-sec-butene isomers with identical masses but different fragmentation patterns. We conclude that the water accessibility of the enzyme active site and the orientation of the hydrophobic alkyl side chain of the substrate are of major importance in determining the regiospecific and stereochemical outcome of vanillyl-alcohol oxidase-mediated conversions of 4-alkylphenols. PMID:9791114

Intrinsic fluorescence biomarkers in cells treated with chemopreventive drugs

NASA Astrophysics Data System (ADS)

Kirkpatrick, Nathaniel D.; Brands, William R.; Zou, Changping; Brewer, Molly A.; Utzinger, Urs

2005-03-01

Non-invasive monitoring of cellular metabolism offers promising insights into areas ranging from biomarkers for drug activity to cancer diagnosis. Fluorescence spectroscopy can be utilized in order to exploit endogenous fluorophores, typically metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), and estimate the redox status of the sample. Fluorescence spectroscopy was applied to follow metabolic changes in epithelial ovarian cells as well as bladder epithelial cancer cells during treatment with a chemopreventive drug that initiates cellular quiescence. Fluorescence signals consistent with NADH, FAD, and tryptophan were measured to monitor cellular activity, redox status, and protein content. Cells were treated with varying concentrations of N-4-(hydroxyphenyl) retinamide (4-HPR) and measured in a stable environment with a sensitive fluorescence spectrometer. A subset of measurements was completed on a low concentration of cells to demonstrate feasibility for medical application such as in bladder or ovary washes. Results suggest that all of the cells responded with similar dose dependence but started at different estimated redox ratio baseline levels correlating with cell cycle, growth inhibition, and apoptosis assays. NADH and tryptophan related fluorescence changed significantly while FAD related fluorescence remained unaltered. Fluorescence data collected from approximately 1000 - 2000 cells, comparable to a bladder or ovary wash, was measurable and useful for future experiments. This study suggests that future intrinsic biomarker measurements may need to be most sensitive to changes in NADH and tryptophan related fluorescence while using FAD related fluorescence to help estimate the baseline redox ratio and predict response to chemopreventive agents.

Studies on the synthesis, spectroscopic analysis, molecular docking and DFT calculations on 1-hydroxy-2-(4-hydroxyphenyl)-4,5-dimethyl-imidazol 3-oxide

NASA Astrophysics Data System (ADS)

Benzon, K. B.; Sheena, Mary Y.; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Pradhan, Kiran; Nanda, Ashis Kumar; Van Alsenoy, C.

2017-02-01

In this work we have investigated in details the spectroscopic and reactive properties of newly synthesized imidazole derivative, namely the 1-hydroxy-2-(4-hydroxyphenyl)-4,5-dimethyl-imidazole 3-oxide (HHPDI). FT-IR and NMR spectra were measured and compared with theoretically obtained data provided by calculations of potential energy distribution and chemical shifts, respectively. Insight into the global reactivity properties has been obtained by analysis of frontier molecular orbitals, while local reactivity properties have been investigated by analysis of charge distribution, ionization energies and Fukui functions. NBO analysis was also employed to understand the stability of molecule, while hyperpolarizability has been calculated in order to assess the nonlinear optical properties of title molecule. Sensitivity towards autoxidation and hydrolysis mechanisms has been investigated by calculations of bond dissociation energies and radial distribution functions, respectively. Molecular docking study was also performed, in order to determine the pharmaceutical potential of the investigated molecule.

Effects of Bisphenol A Metabolite 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene on Lung Function and Type 2 Pulmonary Alveolar Epithelial Cell Growth

PubMed Central

Liu, Shing-Hwa; Su, Chin-Chuan; Lee, Kuan-I; Chen, Ya-Wen

2016-01-01

Bisphenol A (BPA) is recognized as a major pollutant worldwide. 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is a major active metabolite of BPA. The epidemiological and animal studies have reported that BPA is harmful to lung function. The role of MBP in lung dysfunction after BPA exposure still remains unclear. This study investigated whether MBP would induce lung alveolar cell damage and evaluated the role of MBP in the BPA exposure-induced lung dysfunction. An in vitro type 2 alveolar epithelial cell (L2) model and an ex vivo isolated reperfused rat lung model were used to determine the effects of BPA or MBP on cell growth and lung function. MBP, but not BPA, dose-dependently increased the mean artery pressure (Pa), pulmonary capillary pressure (Pc), pulmonary capillary filtration coefficient (Kfc), and wet/dry weight ratio in isolated reperfused rat lungs. MBP significantly reduced cell viability and induced caspases-3/7 cleavage and apoptosis and increased AMP-activated protein kinas (AMPK) phosphorylation and endoplasmic reticulum (ER) stress-related molecules expression in L2 cells, which could be reversed by AMPK-siRNA transfection. These findings demonstrated for the first time that MBP exposure induced type 2 alveolar cell apoptosis and lung dysfunction through an AMPK-regulated ER stress signaling pathway. PMID:27982077

Effects of Bisphenol A Metabolite 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene on Lung Function and Type 2 Pulmonary Alveolar Epithelial Cell Growth.

PubMed

Liu, Shing-Hwa; Su, Chin-Chuan; Lee, Kuan-I; Chen, Ya-Wen

2016-12-16

Bisphenol A (BPA) is recognized as a major pollutant worldwide. 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is a major active metabolite of BPA. The epidemiological and animal studies have reported that BPA is harmful to lung function. The role of MBP in lung dysfunction after BPA exposure still remains unclear. This study investigated whether MBP would induce lung alveolar cell damage and evaluated the role of MBP in the BPA exposure-induced lung dysfunction. An in vitro type 2 alveolar epithelial cell (L2) model and an ex vivo isolated reperfused rat lung model were used to determine the effects of BPA or MBP on cell growth and lung function. MBP, but not BPA, dose-dependently increased the mean artery pressure (Pa), pulmonary capillary pressure (Pc), pulmonary capillary filtration coefficient (K fc ), and wet/dry weight ratio in isolated reperfused rat lungs. MBP significantly reduced cell viability and induced caspases-3/7 cleavage and apoptosis and increased AMP-activated protein kinas (AMPK) phosphorylation and endoplasmic reticulum (ER) stress-related molecules expression in L2 cells, which could be reversed by AMPK-siRNA transfection. These findings demonstrated for the first time that MBP exposure induced type 2 alveolar cell apoptosis and lung dysfunction through an AMPK-regulated ER stress signaling pathway.

Phase II study of oral capsular 4-hydroxyphenylretinamide (4-HPR/fenretinide) in pediatric patients with refractory or recurrent neuroblastoma: A report from the Children’s Oncology Group NSC #374551; IND# 40294

PubMed Central

Villablanca, Judith G.; London, Wendy B.; Naranjo, Arlene; McGrady, Patrick; Ames, Matthew M.; Reid, Joel M.; McGovern, Renee M.; Buhrow, Sarah A.; Jackson, Hollie; Stranzinger, Enno; Kitchen, Brenda J.; Sondel, Paul M.; Parisi, Marguerite T.; Shulkin, Barry; Yanik, Gregory A.; Cohn, Susan L.; Reynolds, C. Patrick

2011-01-01

Purpose To determine the response rate to oral capsular fenretinide in children with recurrent or biopsy proven refractory high-risk neuroblastoma. Experimental Design Patients received 7 days of fenretinide: 2475 mg/m2/day divided TID (<18 years) or 1800 mg/m2/day divided BID (≥18 years) every 21 days for a maximum of 30 courses. Patients with stable or responding disease after course 30 could request additional compassionate courses. Best response by course 8 was evaluated in Stratum 1 (measurable disease on CT/MRI +/− bone marrow and/or MIBG avid sites) and Stratum 2 (bone marrow and/or MIBG avid sites only). Results Sixty-two eligible patients, median age 5 years (range 0.6–19.9), were treated in Stratum 1 (n=38) and Stratum 2 (n=24). One partial response (PR) was seen in Stratum 2 (n=24 evaluable). No responses were seen in Stratum 1 (n=35 evaluable). Prolonged stable disease (SD) was seen in 7 patients in Stratum 1 and 6 patients in Stratum 2 for 4–45+ (median 15) courses. Median time to progression was 40 days (range 17–506) for Stratum 1 and 48 days (range 17–892) for Stratum 2. Mean 4-HPR steady state trough plasma concentrations were 7.25 µM (coefficient of variation 40–56%) at day 7 course 1. Toxicities were mild and reversible. Conclusions Although neither stratum met protocol criteria for efficacy, 1 PR + 13 prolonged SD occurred in 14/59 (24%) of evaluable patients. Low bioavailability may have limited fenretinide activity. Novel fenretinide formulations with improved bioavailability are currently in pediatric Phase I studies. PMID:21908574

Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells

PubMed Central

Bolton, Eric C.

2015-01-01

The androgen receptor (AR) mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT). However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR), and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK) complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation. PMID:26372468

The histidine phosphocarrier protein, HPr, binds to the highly thermostable regulator of sigma D protein, Rsd, and its isolated helical fragments.

PubMed

Neira, José L; Hornos, Felipe; Cozza, Concetta; Cámara-Artigas, Ana; Abián, Olga; Velázquez-Campoy, Adrián

2018-02-01

The phosphotransferase system (PTS) controls the preferential use of sugars in bacteria and it is also involved in other processes, such as chemotaxis. It is formed by a protein cascade in which the first two proteins are general (namely, EI and HPr) and the others are sugar-specific permeases. The Rsd protein binds specifically to the RNA polymerase (RNAP) σ 70 factor. We first characterized the conformational stability of Escherichia coli Rsd. And second, we delineated the binding regions of Streptomyces coelicolor, HPr sc , and E. coli Rsd, by using fragments derived from each protein. To that end, we used several biophysical probes, namely, fluorescence, CD, NMR, ITC and BLI. Rsd had a free energy of unfolding of 15 kcal mol -1 at 25 °C, and a thermal denaturation midpoint of 103 °C at pH 6.5. The affinity between Rsd and HPr sc was 2 μM. Interestingly enough, the isolated helical-peptides, comprising the third (RsdH3) and fourth (RsdH4) Rsd helices, also interacted with HPr sc in a specific manner, and with affinities similar to that of the whole Rsd. Moreover, the isolated peptide of HPr sc , HPr 9-30 , comprising the active site, His15, also was bound to intact Rsd with similar affinity. Therefore, binding between Rsd and HPr sc was modulated by the two helices H3 and H4 of Rsd, and the regions around the active site of HPr sc . This implies that specific fragments of Rsd and HPr sc can be used to interfere with other protein-protein interactions (PPIs) of each other protein. Copyright © 2018 Elsevier Inc. All rights reserved.

Computational insights into the molecular interactions of environmental xenoestrogens 4-tert-octylphenol, 4-nonylphenol, bisphenol A (BPA), and BPA metabolite, 4-methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene (MBP) with human sex hormone-binding globulin.

PubMed

Sheikh, Ishfaq A; Tayubi, Iftikhar A; Ahmad, Ejaz; Ganaie, Majid A; Bajouh, Osama S; AlBasri, Samera F; Abdulkarim, Ibtihal M J; Beg, Mohd A

2017-01-01

Environmental contamination has been one of the major drawbacks of the industrial revolution. Several man-made chemicals are constantly released into the environment during the manufacturing process and by leaching from the industrial products. As a result, human and animal populations are exposed to these synthetic chemicals on a regular basis. Many of these chemicals have adverse effects on the physiological functions, particularly on the hormone systems in human and animals and are called endocrine disrupting chemicals (EDCs). Bisphenol A (BPA), 4-tert-octylphenol (OP), and 4-nonylphenol (NP) are three high volume production EDCs that are widely used for industrial purposes and are present ubiquitously in the environment. Bisphenol A is metabolized in the human body to a more potent compound (MBP: 4-Methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene). Epidemiological and experimental studies have shown the three EDCs to be associated with adverse effects on reproductive system in human and animals. Sex hormone-binding globulin (SHBG) is a circulatory protein that binds sex steroids and is a potential target for endocrine disruptors in the human body. The current study was done in order to understand the binding mechanism of OP, BPA, NP, and MBP with human SHBG using in silico approaches. All four compounds showed high binding affinity with SHBG, however, the binding affinity values were higher (more negative) for MBP and NP than for OP and BPA. The four ligands interacted with 19-23 residues of SHBG and a consistent overlapping of the interacting residues for the four ligands with the residues for the natural ligand, dihydrotestosterone (DHT; 82-91% commonality) was shown. The overlapping SHBG interacting residues among DHT and the four endocrine disruptors suggested that these compounds have potential for interference and disruption in the steroid binding function. Copyright © 2016 Elsevier Inc. All rights reserved.

7-(4-Hydroxyphenyl)-1-phenyl-4E-hepten-3-one, a Diarylheptanoid from Alpinia officinarum, Protects Neurons against Amyloid-β Induced Toxicity.

PubMed

Huang, Xiaojie; Tang, Genyun; Liao, Yumei; Zhuang, Xiaoji; Dong, Xiao; Liu, Hui; Huang, Xiao-Jun; Ye, Wen-Cai; Wang, Ying; Shi, Lei

2016-12-01

Amyloid-β (Aβ) is one of the major causative agents of Alzheimer's disease (AD), the most common neurodegenerative disorder characterized by progressive cognitive impairment. While effective drugs for AD are currently limited, identifying anti-Aβ compounds from natural products has been shown as a promising strategy which may lead to breakthroughs for new drug candidate discovery. We have previously reported that 7-(4-hydroxyphenyl)-1-phenyl-4E-hepten-3-one (AO-1), a diarylheptanoid extracted from the plant Alpinia officinarum, has strong effects on neuronal differentiation and neurite outgrowth in vitro and in vivo. The present study further uncovers that AO-1 exerts neuroprotective effects against the neurotoxicity caused by Aβ. Under the damage of Aβ oligomers, the major pathological forms of Aβ, dendrites of neurons become atrophic and simplified, but such impairments were substantially alleviated by AO-1 treatment. Moreover, AO-1 reduced apoptotic levels and oxidative stress triggered by Aβ. Further analysis showed that the anti-caspase and dendrite protective effects of AO-1 were dependent on activation of phosphatidylinositol 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) pathways. These findings collectively identify AO-1 as a beneficial compound to ameliorate the deleterious effects of Aβ on dendrite integrity and cell survival, and may provide new insights on drug discovery of AD.

Hox proteins activate the IGFBP-1 promoter and suppress the function of hPR in human endometrial cells.

PubMed

Gao, Jiaguo; Mazella, James; Tseng, Linda

2002-11-01

Previous studies have shown that progestin activates the transcription of IGFBP-1 (insulin-like growth factor binding protein-1). Four regions in the IGFBP-1 promotor have been identified to enhance the transcription. Two of the regions, located at -73 to -65 bp and -319 to -311 bp formed identical DNA-protein complexes with the nuclear extracts of endometrial stromal/decidual cells. To identify the binding protein(s) in endometrial cells that interact with these two regions, we have used the TGTCAATTA repeats (-319 to -11 bp of the IGFBP-1 promoter) to screen the human decidual cDNA library by yeast one-hybrid system. We found that Hox A10, HoxA11, HoxB2, HoxB4, and HoxD11 interacted with the TGTCAATTA repeats in yeast cells. Among these hox genes, the full-length coding region of HoxA10, HoxA11, and HoxB4 were used for functional analysis in three types of endometrial cells, undifferentiated endometrial stromal cells, decidual cells (differentiated stromal cells) and endometrial adenocarcinoma cell line (HEC1-B). All these endometrial cells produce IGFBP-1. Transient transfection assay showed that HoxA10 expression vector increased the promoter activity (the IGFBP-1 proximal promoter containing TGC/TCAATTA and two functional PRE sites) in endometrial stromal cells and in HEC-1B cells, but not in decidual cells. HoxB4 enhanced the promoter activity only in decidual cells, while HoxA11 had no apparent effect in all three types of cells. To evaluate whether Hox proteins would interact with progesterone receptor (hPR), cells were transfected with the promoter construct, Hox and hPR expression vectors. hPR alone activated the IGFBP-1 promoter activity, but expression of Hox gene suppressed the activation. Hox proteins also suppressed the hPR enhanced promoter activities of MMTV (containing consensus-PRE sites) and glycodelin (GdA, containing Sp1 site which mediates the hPR function). These data showed that Hox genes selectively activate the transcription of the IGFBP

Synthesis, characterization, crystal structure and theoretical studies of 4-[(E)-(3-chloro-4-hydroxyphenyl) diazenyl]-1, 5-dimethyl-2-phenyl-1, 2-dihydro-3H-pyrazol-3-one

NASA Astrophysics Data System (ADS)

Athira, L. S.; Lakshmi, C. S. Nair; Balachandran, S.; Arul Dhas, D.; Hubert Joe, I.

2017-11-01

Crystals of new heterocyclic azo compound of 4-aminoantipyrine, 4-[(E)-(3-chloro-4-hydroxyphenyl)diazenyl]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one have been grown by slow evaporation method at room temperature and its structural characterization was performed by X- ray diffraction method. The spectroscopic characterization was also performed by FT-IR, UV-Vis, 13C and 1H NMR techniques. The compound crystallizes in the monoclinic CC space group with cell dimensions a = 12.4842 (13), b = 16.4492 (16), c = 8.3389 (8) and β = 102.698 (3)°. The phenyl ring attached to the pyrazolone moiety is disordered over two positions with an occupancy ratio 52:48. The components of the disorder were refined. DFT calculations have been performed by using B3LYP/6-311G (d,p) level basis set. The calculated vibrational frequency showed a red shift for Cdbnd O and OH stretching. The natural bond orbital analysis of monomer, dimer and trimer structures reveals the absence of intramolecular hydrogen bonding; however intermolecular hydrogen bonding is observed. The cationic and anionic reactive sites of compound have been visualized on MEP surface.

Biotransformation of 2-Benzoxazolinone and 2-Hydroxy-1,4-Benzoxazin-3-one by Endophytic Fungi Isolated from Aphelandra tetragona

PubMed Central

Zikmundová, M.; Drandarov, K.; Bigler, L.; Hesse, M.; Werner, C.

2002-01-01

The biotransformation of the phytoanticipins 2-benzoxazolinone (BOA) and 2-hydroxy-1,4-benzoxazin-3-one (HBOA) by four endophytic fungi isolated from Aphelandra tetragona was studied. Using high-performance liquid chromatography-mass spectrometry, several new products of acylation, oxidation, reduction, hydrolysis, and nitration were identified. Fusarium sambucinum detoxified BOA and HBOA to N-(2-hydroxyphenyl)malonamic acid. Plectosporium tabacinum, Gliocladium cibotii, and Chaetosphaeria sp. transformed HBOA to 2-hydroxy-N-(2-hydroxyphenyl)acetamide, N-(2-hydroxyphenyl)acetamide, N-(2-hydroxy-5-nitrophenyl)acetamide, N-(2-hydroxy-3-nitrophenyl)acetamide, 2-amino-3H-phenoxazin-3-one, 2-acetylamino-3H-phenoxazin-3-one, and 2-(N-hydroxy)acetylamino-3H-phenoxazin-3-one. BOA was not degraded by these three fungal isolates. Using 2-hydroxy-N-(2-hydroxyphenyl)[13C2]acetamide, it was shown that the metabolic pathway for HBOA and BOA degradation leads to o-aminophenol as a key intermediate. PMID:12324332

Computational and spectroscopic studies of a new Schiff base 3-hydroxy-4-methoxybenzylidene(2-hydroxyphenyl)amine and molecular structure of its corresponding zwitterionic form.

PubMed

Habibi, Mohammad Hossein; Shojaee, Elahe; Ranjbar, Mahnaz; Memarian, Hamid Reza; Kanayama, Akihiko; Suzuki, Takayoshi

2013-03-15

Computational and spectroscopic properties of a novel Schiff base compound, 3-hydroxy-4-methoxybenzylidene(2-hydroxyphenyl)amine were studied. The crystal structures of the title compound and its corresponding zwitterionic form were analyzed by X-ray diffraction. The presence of N-H, C-O and C=N stretching vibrations in IR spectrum strongly suggest that the title compound has zwitterionic form in the solid state. Molecular geometry of the title compound in the ground state has been calculated using the density functional method (DFT) at B3LYP 6-31++G(d,p) basis set and was compared with the experimental data. The calculated results of the title compound show that the optimized geometry can well reproduce the crystal structure. The molecule shows absorption bands at 345 and 363 nm in EtOH. The shoulder-shaped bands at 415 nm can be assigned to n→π(*) transitions. The absorption band is observed at 285 nm in EtOH corresponds to the π→π(*) transitions. Copyright © 2012 Elsevier B.V. All rights reserved.

HPr antagonizes the anti-σ70 activity of Rsd in Escherichia coli.

PubMed

Park, Young-Ha; Lee, Chang-Ro; Choe, Mangyu; Seok, Yeong-Jae

2013-12-24

The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) is a multicomponent system that participates in a variety of physiological processes in addition to the phosphorylation-coupled transport of numerous sugars. In Escherichia coli and other enteric bacteria, enzyme IIA(Glc) (EIIA(Glc)) is known as the central processing unit of carbon metabolism and plays multiple roles, including regulation of adenylyl cyclase, the fermentation/respiration switch protein FrsA, glycerol kinase, and several non-PTS transporters, whereas the only known regulatory role of the E. coli histidine-containing phosphocarrier protein HPr is in the activation of glycogen phosphorylase. Because HPr is known to be more abundant than EIIA(Glc) in enteric bacteria, we assumed that there might be more regulatory mechanisms connected with HPr. The ligand fishing experiment in this study identified Rsd, an anti-sigma factor known to complex with σ(70) in stationary-phase cells, as an HPr-binding protein in E. coli. Only the dephosphorylated form of HPr formed a tight complex with Rsd and thereby inhibited complex formation between Rsd and σ(70). Dephosphorylated HPr, but not phosphorylated HPr, antagonized the inhibitory effect of Rsd on σ(70)-dependent transcriptions both in vivo and in vitro, and also influenced the competition between σ(70) and σ(S) for core RNA polymerase in the presence of Rsd. Based on these data, we propose that the anti-σ(70) activity of Rsd is regulated by the phosphorylation state-dependent interaction of HPr with Rsd.

HPr antagonizes the anti-σ70 activity of Rsd in Escherichia coli

PubMed Central

Park, Young-Ha; Lee, Chang-Ro; Choe, Mangyu; Seok, Yeong-Jae

2013-01-01

The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) is a multicomponent system that participates in a variety of physiological processes in addition to the phosphorylation-coupled transport of numerous sugars. In Escherichia coli and other enteric bacteria, enzyme IIAGlc (EIIAGlc) is known as the central processing unit of carbon metabolism and plays multiple roles, including regulation of adenylyl cyclase, the fermentation/respiration switch protein FrsA, glycerol kinase, and several non-PTS transporters, whereas the only known regulatory role of the E. coli histidine-containing phosphocarrier protein HPr is in the activation of glycogen phosphorylase. Because HPr is known to be more abundant than EIIAGlc in enteric bacteria, we assumed that there might be more regulatory mechanisms connected with HPr. The ligand fishing experiment in this study identified Rsd, an anti-sigma factor known to complex with σ70 in stationary-phase cells, as an HPr-binding protein in E. coli. Only the dephosphorylated form of HPr formed a tight complex with Rsd and thereby inhibited complex formation between Rsd and σ70. Dephosphorylated HPr, but not phosphorylated HPr, antagonized the inhibitory effect of Rsd on σ70-dependent transcriptions both in vivo and in vitro, and also influenced the competition between σ70 and σS for core RNA polymerase in the presence of Rsd. Based on these data, we propose that the anti-σ70 activity of Rsd is regulated by the phosphorylation state-dependent interaction of HPr with Rsd. PMID:24324139

Genetic analysis and comparative virulence of infectious salmon anemia virus (ISAV) types HPR7a and HPR7b from recent field outbreaks in Chile.

PubMed

Godoy, Marcos G; Suarez, Rudy; Lazo, Eduardo S; Llegues, Katerina O; Kibenge, Molly J T; Wang, Yingwei; Kibenge, Frederick S B

2014-11-29

Infectious salmon anemia (ISA) is a serious disease of marine farmed Atlantic salmon, Salmo salar L. caused by ISA virus (ISAV). ISAV genomic segments 5 and 6 encode surface glycoproteins hemagglutinin-esterase (HE) and F protein important for the pathogenicity of ISAV. In this study, we describe the genetic characteristics and relationship between ISAV-HPR7a and ISAV-HPR7b strains that caused the ISA outbreaks in Chile in 2013 and 2014, respectively, and the evolution of the ISAV clades since 2009 based on segment 5 and 6 sequences. The study material included samples from six ISA cases in Chile. RNA was extracted from salmon tissues and ISAV isolated from cell culture; segments 5 and 6 were amplified by RT-PCR and compared by alignment with ISAV sequences from the GenBank database. ISAV-HPR7a and ISAV-HPR7b belong to the European Genotype I strains only found in Europe and Chile, and in both cases, show high similarity in segments 5 and 6 with identity between 95-96%. Our data confirm the hypothesis that the original virus was introduced to Chile in 1996. Compared to the 2007 ISAV-HPR7b isolate, the 2014 ISAV-HPR7b does not have an insertion in segment 5 and was associated with low mortality, which suggests that ISAV virulence was attenuated by the absence of the insertion in segment 5. In contrast, the highly virulent ISAV-HPR14 from April 2013 outbreak did not have the insertion in segment 5 either. Variability in the ISAV virulence markers supports the quasispecies theory that multiple evolution forces are likely to shape ISAV genetic diversity. Our findings provide evidence of continuing evolution of ISAV in the Chilean aquaculture industry.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene--A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight.

PubMed

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A; Abuzenadah, Adel M; Damanhouri, Ghazi A; Bajouh, Osama S; AlBasri, Samera F; Assiri, Mansour M; Beg, Mohd A

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene—A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight

PubMed Central

Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A.; Abuzenadah, Adel M.; Damanhouri, Ghazi A.; Bajouh, Osama S.; AlBasri, Samera F.; Assiri, Mansour M.; Beg, Mohd A.

2015-01-01

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR

MMP-2, MMP-9, and TIMP-4 and Response to Aspirin in Diabetic and Nondiabetic Patients with Stable Coronary Artery Disease: A Pilot Study

PubMed Central

Kuliczkowski, Wiktor; Radomski, Marek; Gąsior, Mariusz; Urbaniak, Joanna; Kaczmarski, Jacek; Mysiak, Andrzej; Negrusz-Kawecka, Marta

2017-01-01

Background High on-aspirin treatment platelets reactivity (HPR) is a significant problem in long-term secondary prevention of cardiovascular events. We hypothesize that imbalance between platelets MMPs/TIMPs results in cardiovascular disorders. We also explored whether chronically elevated blood glucose affects MMP-2/TIMP-4 release from platelets. Materials and Methods Seventy patients with stable coronary artery disease, supplemented with aspirin, participated in this pilot study. The presence of HPR and/or diabetes mellitus was considered as the differentiating factor. Light aggregometry, impedance aggregometry, and ELISA tests for TXB2, MMP-2, MMP-9, and TIMP-4 were performed in serum, plasma, platelet-rich plasma, and platelets-poor plasma, as appropriate. Results Aspirin-HPR did not affect plasma MMP-2, MMP-9, and TIMP-4. Arachidonic acid-induced aggregation of platelets from aspirin-HPR patients did not lead to increased release of MMP-2, MMP-9, and TIMP-4. Studying patients at the lowest TXB2 serum concentration quartile revealed that high concentration of plasma TIMP-4 and TIMP-4 negatively correlated with TXB2 and platelet aggregation. Diabetics showed an increased plasma MMP-2 as well as an increased MMP-2 in supernatants after platelet aggregation. However, diabetes mellitus did not affect MMP-9 and TIMP-4. Conclusion Aspirin-HPR did not affect the translocation and release of MMPs and TIMP-4 from platelets. TIMP-4 may serve as a marker of TXA2-mediated platelet aggregation. Chronically elevated plasma glucose increases plasma MMP-2, and HPR potentiates this phenomenon. PMID:28770228

Evidence for an arene oxide-NIH shift pathway in the metabolic conversion of phenytoin to 5-(4-hydroxyphenyl)-5-phenylhydantoin in the rat and in man

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

Claesen, M.; Moustafa, M.A.; Adline, J.

To determine whether the hydroxylation of 5,5-diphenylhydantoin (DPH) to 5-(4-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) occurs by an arene oxide-NIH shift process, racemic 5-(4-deuteriophenyl)-5-phenylhydantoin (p-2H-DPH) was subjected to in vivo metabolic experiments in the rat and in man. After enzymatic hydrolysis of the urine, para-hydroxylated metabolites were separated by HPLC. Deuterium retention in the isolated metabolites determined by gas chromatography-mass spectrometry, was 68-72%. The results are interpreted as the predominance of an arene oxide-NIH shift pathway in those two metabolic systems. Induction of rats with phenobarbital or 3-methylcholanthrene showed no effect on the value of deuterium retention.

The HPr Proteins from the Thermophile Bacillus stearothermophilus Can Form Domain-swapped Dimers

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

Sridharan, Sudharsan; Razvi, Abbas; Scholtz, J. Martin

2010-07-20

The study of proteins from extremophilic organisms continues to generate interest in the field of protein folding because paradigms explaining the enhanced stability of these proteins still elude us and such studies have the potential to further our knowledge of the forces stabilizing proteins. We have undertaken such a study with our model protein HPr from a mesophile, Bacillus subtilis, and a thermophile, Bacillus stearothermophilus. We report here the high-resolution structures of the wild-type HPr protein from the thermophile and a variant, F29W. The variant proved to crystallize in two forms: a monomeric form with a structure very similar tomore » the wild-type protein as well as a domain-swapped dimer. Interestingly, the structure of the domain-swapped dimer for HPr is very different from that observed for a homologous protein, Crh, from B. subtilis. The existence of a domain-swapped dimer has implications for amyloid formation and is consistent with recent results showing that the HPr proteins can form amyloid fibrils. We also characterized the conformational stability of the thermophilic HPr proteins using thermal and solvent denaturation methods and have used the high-resolution structures in an attempt to explain the differences in stability between the different HPr proteins. Finally, we present a detailed analysis of the solution properties of the HPr proteins using a variety of biochemical and biophysical methods.« less

Streptococcal phosphoenolpyruvate-sugar phosphotransferase system: amino acid sequence and site of ATP-dependent phosphorylation of HPr

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

Deutscher, J.; Pevec, B.; Beyreuther, K.

1986-10-21

The amino acid sequence of histidine-containing protein (HPr) from Streptococcus faecalis has been determined by direct Edman degradation of intact HPr and by amino acid sequence analysis of tryptic peptides, V8 proteolyptic peptides, thermolytic peptides, and cyanogen bromide cleavage products. HPr from S. faecalis was found to contain 89 amino acid residues, corresponding to a molecular weight of 9438. The amino acid sequence of HPr from S. faecalis shows extended homology to the primary structure of HPr proteins from other bacteria. Besides the phosphoenolpyruvate-dependent phosphorylation of a histidyl residue in HPr, catalyzed by enzyme I of the bacterial phosphotransferase system,more » HPr was also found to be phosphorylated at a seryl residue in an ATP-dependent protein kinase catalyzed reaction. The site of ATP-dependent phosphorylation in HPr of S faecalis has now been determined. (/sup 32/P)P-Ser-HPr was digested with three different proteases, and in each case, a single labeled peptide was isolated. Following digestion with subtilisin, they obtained a peptide with the sequence -(P)Ser-Ile-Met-. Using chymotrypsin, they isolated a peptide with the sequence -Ser-Val-Asn-Leu-Lys-(P)Ser-Ile-Met-Gly-Val-Met-. The longest labeled peptide was obtained with V8 staphylococcal protease. According to amino acid analysis, this peptide contained 36 out of the 89 amino acid residues of HPr. The following sequence of 12 amino acid residues of the V8 peptide was determined: -Tyr-Lys-Gly-Lys-Ser-Val-Asn-Leu-Lys-(P)Ser-Ile-Met-. Thus, the site of ATP-dependent phosphorylation was determined to be Ser-46 within the primary structure of HPr.« less

Formation and stability of gas-phase o-benzoquinone from oxidation of ortho-hydroxyphenyl: A combined neutral and distonic radical study

DOE PAGES

Prendergast, Matthew B.; Kirk, Benjamin B.; Savee, John D.; ...

2015-10-19

Gas-phase product detection studies of o-hydroxyphenyl radical and O 2 are reported at 373, 500, and 600 K, at 4 Torr (533.3 Pa), using VUV time-resolved synchrotron photoionisation mass spectrometry. The dominant products are assigned as o-benzoquinone (C 6H 4O 2, m/z 108) and cyclopentadienone (C 5H 4O, m/z 80). It is concluded that cyclopentadienone forms as a secondary product from prompt decomposition of o-benzoquinone (and dissociative ionization of o-benzoquinone may contribute to the m/z 80 signal at photon energies ≳9.8 eV). Ion-trap reactions of the distonic o-hydroxyphenyl analogue, the 5-ammonium-2-hydroxyphenyl radical cation, with O 2 are also reported andmore » concur with the assignment of o-benzoquinone as the dominant product. In addition, the ion-trap study also provides support for a mechanism where cyclopentadienone is produced by decarbonylation of o-benzoquinone. Kinetic studies compare oxidation of the ammonium-tagged o-hydroxyphenyl and o-methylphenyl radical cations along with trimethylammonium-tagged analogues. Reaction efficiencies are found to be ca. 5% for both charge-tagged o-hydroxyphenyl and o-methylphenyl radicals irrespective of the charged substituent. G3X-K quantum chemical calculations are deployed to rationalise experimental results for o-hydroxyphenyl + O 2 and its charge-tagged counterpart. The prevailing reaction mechanism, after O 2 addition, involves a facile 1,5-H shift in the peroxyl radical and subsequent elimination of OH to yield o-benzoquinone that is reminiscent of the Waddington mechanism for β-hydroxyperoxyl radicals. These results suggest o-hydroxyphenyl + O 2 and decarbonylation of o-benzoquinone serve as plausible OH and CO sources in combustion.« less

Solution structure of the phosphoryl transfer complex between the cytoplasmic A domain of the mannitol transporter IIMannitol and HPr of the Escherichia coli phosphotransferase system.

PubMed

Cornilescu, Gabriel; Lee, Byeong Ryong; Cornilescu, Claudia C; Wang, Guangshun; Peterkofsky, Alan; Clore, G Marius

2002-11-01

The solution structure of the complex between the cytoplasmic A domain (IIA(Mtl)) of the mannitol transporter II(Mannitol) and the histidine-containing phosphocarrier protein (HPr) of the Escherichia coli phosphotransferase system has been solved by NMR, including the use of conjoined rigid body/torsion angle dynamics, and residual dipolar couplings, coupled with cross-validation, to permit accurate orientation of the two proteins. A convex surface on HPr, formed by helices 1 and 2, interacts with a complementary concave depression on the surface of IIA(Mtl) formed by helix 3, portions of helices 2 and 4, and beta-strands 2 and 3. The majority of intermolecular contacts are hydrophobic, with a small number of electrostatic interactions at the periphery of the interface. The active site histidines, His-15 of HPr and His-65 of IIA(Mtl), are in close spatial proximity, and a pentacoordinate phosphoryl transition state can be readily accommodated with no change in protein-protein orientation and only minimal perturbations of the backbone immediately adjacent to the histidines. Comparison with two previously solved structures of complexes of HPr with partner proteins of the phosphotransferase system, the N-terminal domain of enzyme I (EIN) and enzyme IIA(Glucose) (IIA(Glc)), reveals a number of common features despite the fact that EIN, IIA(Glc), and IIA(Mtl) bear no structural resemblance to one another. Thus, entirely different underlying structural elements can form binding surfaces for HPr that are similar in terms of both shape and residue composition. These structural comparisons illustrate the roles of surface and residue complementarity, redundancy, incremental build-up of specificity and conformational side chain plasticity in the formation of transient specific protein-protein complexes in signal transduction pathways.

Poly(1,3,4-oxadiazoles) via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Wolf, Peter (Inventor)

1992-01-01

Poly(1,3,4-oxadiazoles) (POX) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) 1,3,4-oxadiazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) 1,3,4-oxadiazole monomers are synthesized by reacting 4-hydroxybenzoic hydrazide with phenyl 4-hydrobenzoate in the melt and also by reacting aromatic dihydrazides with two moles of phenyl 4-hydroxybenzoate in the melt. This synthetic route has provided high molecular weight POX of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the large variety of activated aromatic dihalides which are available.

Di(hydroxyphenyl)- benzimidazole monomers

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

1993-01-01

Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

4,4\\'-Methylene bis(N,N\\'-dimethyl)aniline

Integrated Risk Information System (IRIS)

4,4 ' - Methylene bis ( N , N ' - dimethyl ) aniline ; CASRN 101 - 61 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Haz

Order-parameter tensor description of HPr in a medium of oriented bicelles.

PubMed

van Lune, Franciska; Manning, Linda; Dijkstra, Klaas; Berendsen, Herman J C; Scheek, Ruud M

2002-07-01

Residual dipolar couplings between 15N and 1H nuclear spins in HPr were used to determine the protein's orientation in a medium of bicelles, oriented by a magnetic field. In the case of wild-type HPr the protein's non-spherical shape can explain its orientation in this medium. In the case of the F48W mutant it was found that at least one other mechanism contributes to the observed orientation of the protein, to a degree that depends on the concentration of phosphate ions in the medium. We propose that the F48W mutant has a weak affinity towards the bicelle-surfaces that decreases with increasing phosphate concentrations. We used an order-parameter description to analyse this situation and to determine the axis of main order and the sign of the order parameter pertaining to this additional orientation mechanism.

One pot synthesis, X-ray crystal structure of 2-(2‧-hydroxyphenyl)oxazolo[4,5-b]pyridine derivatives and studies of their optical properties

NASA Astrophysics Data System (ADS)

Briseño-Ortega, Horacio; Juárez-Guerra, Lizbeth; Rojas-Lima, Susana; Mendoza-Huizar, Luis Humberto; Vázquez-García, Rosa A.; Farfán, Norberto; Arcos-Ramos, Rafael; Santillan, Rosa; López-Ruiz, Heralio

2018-04-01

A series of five 2-(2-hydroxyphenyl)oxazolo [4,5-b]pyridines (HPOP) (3a-e), where four are novel, were synthesized by a mild, one pot, phenylboronic acid-NaCN catalyzed reaction. Spectroscopic characterization and photophysical properties of these compounds are reported. Absorption and excitation spectra of the compounds were dependent on the substituents in the phenyl ring. Fluorescence quantum yields (0.009-0.538) were associated with the donor strength and the position of the substituents. Also, DFT analysis allowed us to determine the contribution of diethylamino and methoxy moieties to the π-system, which is in agreement with the experimental data analyzed in solution and by cyclic voltammetry. The results obtained in the solid state by single-crystal X-ray diffraction experiments indicate that, the quasi-planarity envisioned for the explored compounds is present, supporting the hypothesis that both the H-bonding of a hydroxyl group to the Cdbnd N moiety and a donor groups such as diethylamino and methoxy moieties favor an electronic communication. Due to the facile synthesis and their photophysical properties, the novel HPOP 3a-e have potential application as organic semiconductors.

A combined crystallographic, thermal, Raman and computational study on polymorphism and phase transition in 1-(4-hexyloxy-3-hydroxyphenyl)ethanone.

PubMed

Suárez, Sebastián; Manzano, Veronica E; Fantoni, Adolfo C; Halac, Emilia; Baggio, Ricardo; Cukiernik, Fabio D

2017-12-01

The crystal structure of the triclinic polymorph of 1-(4-hexyloxy-3-hydroxyphenyl)ethanone, C 14 H 20 O 3 , differs markedly from that of the orthorhombic polymorph [Manzano et al. (2015). Acta Cryst. C71, 1022-1027]. The two molecular structures are alike with respect to their bond lengths and angles, but differ in their spatial arrangement. This gives rise to quite different packing schemes, even if built up by similar chains having the hydroxy-ethanone O-H...O hydrogen-bond synthon in common. Both phases were found to be related by a first-order thermally driven phase transformation at 338-340 K, which is discussed in detail. The relative stabilities of both polymorphs are explained on the basis of both the noncovalent interactions operating in each structure and quantum chemical calculations. The polymorphic phase transition has also been studied experimentally by means of differential scanning calorimetry (DSC) experiments, conducted on individual single crystals, Raman spectroscopy and controlled heating under a microscope of individual single crystals, which were further characterized by powder and single-crystal X-ray diffraction.

Effect of 3-(3'-tert-butyl-4'-hydroxyphenyl)propyl thiosulfonate sodium on expression of GSTP1 and NQO1 genes and protein transcription factors in BALB/c mouse liver.

PubMed

Shintyapina, A B; Safronova, O G; Vavilin, V A; Kandalintseva, N V; Prosenko, A E; Lyakhovich, V V

2014-08-01

The study examined dynamics of the effect of novel phenol antioxidant preparation 3-(3'-tertbutyl- 4'-hydroxyphenyl)propyl thiosulfonate sodium (TS-13) on expression of antioxidant protection enzymes genes GSTP1 and NQO1 and on the content of protein transcription factors NF-κB and ATF-2 in mouse liver. Expression of GSTP1 gene decreased significantly on days 4 and 7 after per os administration of TS-13 (100 mg/kg), but increased on post-administration day 14. On days 7 and 14 post-administration, expression of NQO1 gene was significantly increased. On day 7, the hepatic content of the phosphorylated form of ATF-2 and two subunits of nuclear factor NF-κB (p50, p65) decreased significantly.

Highly selective "turn-on" fluorescent and colorimetric sensing of fluoride ion using 2-(2-hydroxyphenyl)-2,3-dihydroquinolin-4(1H)-one based on excited-state proton transfer.

PubMed

Kanagaraj, Kuppusamy; Pitchumani, Kasi

2014-01-01

A simple, highly selective and sensitive colorimetric system for the detection of fluoride ion in an aqueous medium has been developed using 2-(2-hydroxyphenyl)-2,3-dihydroquinolin-4(1H)-one. This system allows selective "turn-on" fluorescence detection of fluoride ion, which is found to be dependent upon guest basicity. An excited-state proton transfer is proposed to be the signaling mechanism, which is rationalized by DFT and TD-DFT calculations. The present sensor can also be applied to detect fluoride levels in real water samples. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 721.1085 - Benzenamine,4,4′-methylenebis[N-ethyl-N-methyl-.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenamine,4,4â²-methylenebis[N-ethyl-N-methyl-. 721.1085 Section 721.1085 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1085 Benzenamine,4,4′-methylenebis[N-ethyl-N-methyl-. (a) Chemical...

40 CFR 721.1085 - Benzenamine,4,4′-methylenebis[N-ethyl-N-methyl-.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenamine,4,4â²-methylenebis[N-ethyl-N-methyl-. 721.1085 Section 721.1085 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1085 Benzenamine,4,4′-methylenebis[N-ethyl-N-methyl-. (a) Chemical...

Crystallization, Preliminary X-ray Analysis and Biophysical Characterization of HPr Kinase/Phosphatase of Mycoplasma pneumoniae

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

Steinhauer, K.

2002-01-01

The Mycoplasma pneumoniae HPr kinase/phosphatase (HPrK/P) is a member of a large family of enzymes which are central to carbon regulation in Gram-positive bacteria. The full-length M. pneumonia HPrK/P was crystallized from solutions of polyethylene glycol 8000 and KCl or NaCl which also contained the non-hydrolysable ATP analog adenosine 5'-[{beta},{gamma}-methylene]triphosphate (AMPPCP). The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 117.1, b = 127.7, c = 170.7 {angstrom}. A complete X-ray intensity data set has been collected and processed to 2.50 {angstrom} resolution. The slow self-rotation function revealed the presence of amore » sixfold axis. Dynamic light-scattering (DLS) experiments indicated a molecular weight of 197 kDa for HPrK/P in the absence of AMPPCP and of 217 kDa in the presence of the ATP analog. Thus, the biophysical and crystallographic data suggest that HPrK/P is a functional hexamer that undergoes an ATP-binding-induced conformational change.« less

Poly(N-arylenbenzimidazoles) via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

1995-01-01

Novel poly(N-arylenebenzimidazole)s (PNABIs) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl N-arylenebenzimidazole) monomers are synthesized by reacting phenyl 4-hydroxybenzoate with bis(2-aminoanilino) arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyl N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Estrogenic Mechanisms and Cardiac Responses Following Early Life Exposure to Bisphenol A (BPA) and Its Metabolite 4-Methyl-2,4-bis( p-hydroxyphenyl)pent-1-ene (MBP) in Zebrafish.

PubMed

Moreman, John; Takesono, Aya; Trznadel, Maciej; Winter, Matthew J; Perry, Alexis; Wood, Mark E; Rogers, Nicola J; Kudoh, Tetsuhiro; Tyler, Charles R

2018-06-05

Environmental exposure to Bisphenol A (BPA) has been associated with a range of adverse health effects, including on the cardiovascular system in humans. Lack of agreement on its mechanism(s) of action likely stem from comparisons between in vivo and in vitro test systems and potential multiple effects pathways. In rodents, in vivo, metabolic activation of BPA produces 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), which is reported to be up to 1000 times more potent as an estrogen than BPA. We investigated the estrogenic effects and estrogen receptor signaling pathway(s) of BPA and MBP following early life exposure using a transgenic, estrogen responsive (ERE-TG) zebrafish and a targeted morpholino approach to knockdown the three fish estrogen receptor (ER) subtypes. The functional consequences of BPA exposure on the cardiovascular system of zebrafish larvae were also examined. The heart atrioventricular valves and the bulbus arteriosus were primary target tissues for both BPA and MBP in the ERE-TG zebrafish, and MBP was approximately 1000-fold more potent than BPA as an estrogen in these tissues. Estrogen receptor knockdown with morpholinos indicated that the estrogenic responses in the heart for both BPA and MBP were mediated via an estrogen receptor 1 (esr1) dependent pathway. At the highest BPA concentration tested (2500 μg/L), alterations in the atrial:ventricular beat ratio indicated a functional impact on the heart of 5 days post fertilization (dpf) larvae, and there was also a significantly reduced heart rate in these larvae at 14 dpf. Our findings indicate that some of the reported adverse effects on heart function associated with BPA exposure (in mammals) may act through an estrogenic mechanism, but that fish are unlikely to be susceptible to adverse effects on heart development for environmentally relevant exposures.

Effect of phosphorylation on hydrogen-bonding interactions of the active site histidine of the phosphocarrier protein HPr of the phosphoenolpyruvate-dependent phosphotransferase system determined by sup 15 N NMR spectroscopy

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

van Dijk, A.A.; de Lange, L.C.M.; Robillard, G.T.

1990-09-04

The phosphocarrier protein HPr of the phosphoenolpyruvate-dependent sugar transport system of Escherichia coli can exist in a phosphorylated and a nonphosphorylated form. During phosphorylation, the phosphoryl group is carried on a histidine residue, His15. The hydrogen-bonding state of this histidine was examined with {sup 15}N NMR. For this purpose we selectively enriched the histidine imidazole nitrogens with {sup 15}N by supplying an E. coli histidine auxotroph with the amino acid labeled either at the N{delta}1 and N{epsilon}2 positions or at only the N{delta}1 position. {sup 15}N NMR spectra of two synthesized model compound, phosphoimidazole and phosphomethylimidazole, were also recorded. Themore » authors show that, prior to phosphorylation, the protonated His15 N{epsilon}2 is strongly hydrogen bonded, most probably to a carboxylate moiety. The H-bond should strengthen the nucleophilic character of the deprotonated N{delta}1, resulting in a good acceptor for the phosphoryl group. The hydrogen bond to the His15 N{delta}1 breaks upon phosphorylation of the residue. Implications of the H-bond structure for the mechanism of phosphorylation of HPr are discussed.« less

Malate-mediated carbon catabolite repression in Bacillus subtilis involves the HPrK/CcpA pathway.

PubMed

Meyer, Frederik M; Jules, Matthieu; Mehne, Felix M P; Le Coq, Dominique; Landmann, Jens J; Görke, Boris; Aymerich, Stéphane; Stülke, Jörg

2011-12-01

Most organisms can choose their preferred carbon source from a mixture of nutrients. This process is called carbon catabolite repression. The Gram-positive bacterium Bacillus subtilis uses glucose as the preferred source of carbon and energy. Glucose-mediated catabolite repression is caused by binding of the CcpA transcription factor to the promoter regions of catabolic operons. CcpA binds DNA upon interaction with its cofactors HPr(Ser-P) and Crh(Ser-P). The formation of the cofactors is catalyzed by the metabolite-activated HPr kinase/phosphorylase. Recently, it has been shown that malate is a second preferred carbon source for B. subtilis that also causes catabolite repression. In this work, we addressed the mechanism by which malate causes catabolite repression. Genetic analyses revealed that malate-dependent catabolite repression requires CcpA and its cofactors. Moreover, we demonstrate that HPr(Ser-P) is present in malate-grown cells and that CcpA and HPr interact in vivo in the presence of glucose or malate but not in the absence of a repressing carbon source. The formation of the cofactor HPr(Ser-P) could be attributed to the concentrations of ATP and fructose 1,6-bisphosphate in cells growing with malate. Both metabolites are available at concentrations that are sufficient to stimulate HPr kinase activity. The adaptation of cells to environmental changes requires dynamic metabolic and regulatory adjustments. The repression strength of target promoters was similar to that observed in steady-state growth conditions, although it took somewhat longer to reach the second steady-state of expression when cells were shifted to malate.

Two New Isomers of Palmityl-4-hydroxycinnamate from Flowers of Taraxacum Species.

PubMed

Dudáš, Matej; Vilková, Mária; Béres, Tibor; Repcák, Miroslav; Mártonfi, Pavol

2016-06-01

Two isomers, (Z)- and (E)-palmityl 4-hydroxycinnamate [hexadecyl(2Z)-3-(4-hydroxyphenyl)prop-2-enoate and hexadecyl(2E)-3-(4-hydroxyphenyl)prop-2-enoate] were isolated for the first time from ligulate flowers of Taraxacum linearisquameum Soest (sect. Taraxacum). The highest amount of these compounds was detected in pollen grains; 0.26 mg/100 mg DW of the (E)-isomer and 0.096 mg/100 mg DW of the (Z)-isomer. The structures of these compounds were elucidated by a combination of HPLC-ESI-Qtof-MS and 1D and 2D NMR spectroscopy. Their presence was confirmed in other species of Taraxacum, but they were not found in the male - sterile triploid agamospermous taxon T. parnassicum.

Analysis of the use of codon pairs in the HE gene of the ISA virus shows a correlation between bias in HPR codon-pair use and mortality rates caused by the virus

PubMed Central

2013-01-01

Background Segment 6 of the ISA virus codes for hemoagglutinin-esterase (HE). This segment is highly variable, with more than 26 variants identified. The major variation is observed in what is called the high polymorphism region (HPR). The role of the different HPR zones in the viral cycle or evolution remains unknown. However viruses that present the HPR0 are avirulent, while viruses with important deletions in this region have been responsible for outbreaks with high mortality rates. In this work, using bioinformatic tools, we examined the influence of different HPRs on the adaptation of HE genes to the host translational machinery and the relationship to observed virulence. Methods Translational efficiency of HE genes and their HPR were estimated analyzing codon-pair bias (CPB), adaptation to host codon use (codon adaptation index - CAI) and the adaptation to available tRNAs (tAI). These values were correlated with reported mortality for the respective ISA virus and the ΔG of RNA folding. tRNA abundance was inferred from tRNA gene numbers identified in the Salmo salar genome using tRNAScan-SE. Statistical correlation between data was performed using a non-parametric test. Results We found that HPR0 contains zones with codon pairs of low frequency and low availability of tRNA with respect to salmon codon-pair usage, suggesting that HPR modifies HE translational efficiency. Although calculating tAI was impossible because one third of tRNAs (~60.000) were tRNA-ala, translational efficiency measured by CPB shows that as HPR size increases, the CPB value of the HE gene decreases (P = 2x10-7, ρ = −0.675, n = 63) and that these values correlate positively with the mortality rates caused by the virus (ρ = 0.829, P = 2x10-7, n = 11). The mortality associated with different virus isolates or their corresponding HPR sizes were not related with the ΔG of HPR RNA folding, suggesting that the secondary structure of HPR RNA does not modify virulence. Conclusions Our

Common structural changes accompany the functional inactivation of HPr by seryl phosphorylation or by serine to aspartate substitution

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

Wittekind, M.; Klevit, R.E.; Reizer, J.

1989-12-26

Although many proteins are known to be regulated via reversible phosphorylation, little is known about the mechanism by which the covalent modification of seryl, threonyl, or tyrosyl residues alters the activities of the target systems. To address this question, modified versions of bacillus subtilus HPr, a protein component of the bacterial phosphotransferase system, have been studied by {sup 1}H NMR spectroscopy. Phosphorylation at Ser{sub 46} or a Ser to Asp substitution at this position inactivates HPr. Two-dimensional spectra of these two modified proteins display nearly identical proton chemical shifts that differ significantly from those observed in the spectra of themore » unphosphorylated, wild-type protein and of functionally active HPr mutants. These results demonstrate that the functional inactivation of HPr brought about by the serine to aspartate mutation is accompanied by the same structural changes that occur when HPr is phosphorylated at Ser{sub 46}.« less

Design, synthesis, and biological evaluation of novel biphenyl-4-carboxamide derivatives as orally available TRPV1 antagonists.

PubMed

Oka, Hiromasa; Yonezawa, Koichi; Kamikawa, Akio; Ikegai, Kazuhiro; Asai, Norio; Shirakami, Shohei; Miyamoto, Satoshi; Watanabe, Toshihiro; Kiso, Tetsuo; Takemoto, Yukihiro; Tamura, Seiji; Kuramochi, Takahiro

2018-07-23

A new series of transient receptor potential vanilloid type 1 (TRPV1) antagonists were designed and synthesized from N-(3-hydroxyphenyl)-2-(piperidin-1-ylmethyl)biphenyl-4-carboxamide hydrochloride (8). SAR studies identified (R)-N-(1-methyl-2-oxo-1,2,3,4-tetrahydro-7-quinolyl)-2-[(2-methylpyrrolidin-1-yl)methyl]biphenyl-4-carboxamide hydrochloride (ASP8370, 7), as a compound with high aqueous solubility, satisfactory stability in human liver microsomes, and reduced CYP3A4 inhibition. ASP8370 was selected as a clinical development candidate with significant ameliorative effects on neuropathic pain. SAR studies also revealed the structural mechanisms underlying the switching between TRPV1 antagonism and agonism. Copyright © 2018 Elsevier Ltd. All rights reserved.

Crystal structures of 4-meth-oxy-N-(4-methyl-phenyl)benzene-sulfonamide and N-(4-fluoro-phenyl)-4-meth-oxy-benzene-sulfonamide.

PubMed

Rodrigues, Vinola Z; Preema, C P; Naveen, S; Lokanath, N K; Suchetan, P A

2015-11-01

Crystal structures of two N-(ar-yl)aryl-sulfonamides, namely, 4-meth-oxy-N-(4-methyl-phen-yl)benzene-sulfonamide, C14H15NO3S, (I), and N-(4-fluoro-phen-yl)-4-meth-oxy-benzene-sulfonamide, C13H12FNO3S, (II), were determined and analyzed. In (I), the benzene-sulfonamide ring is disordered over two orientations, in a 0.516 (7):0.484 (7) ratio, which are inclined to each other at 28.0 (1)°. In (I), the major component of the sulfonyl benzene ring and the aniline ring form a dihedral angle of 63.36 (19)°, while in (II), the planes of the two benzene rings form a dihedral angle of 44.26 (13)°. In the crystal structure of (I), N-H⋯O hydrogen bonds form infinite C(4) chains extended in [010], and inter-molecular C-H⋯πar-yl inter-actions link these chains into layers parallel to the ab plane. The crystal structure of (II) features N-H⋯O hydrogen bonds forming infinite one dimensional C(4) chains along [001]. Further, a pair of C-H⋯O inter-molecular inter-actions consolidate the crystal packing of (II) into a three-dimensional supra-molecular architecture.

Structural basis for the sequestration of the anti-σ(70) factor Rsd from σ(70) by the histidine-containing phosphocarrier protein HPr.

PubMed

Park, Young Ha; Um, Si Hyeon; Song, Saemee; Seok, Yeong Jae; Ha, Nam Chul

2015-10-01

Histidine-containing phosphocarrier protein (HPr) is a general component of the bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) involved in the phosphorylation-coupled transport of numerous sugars called PTS sugars. HPr mainly exists in a dephosphorylated form in the presence of PTS sugars in the medium, while its phosphorylation increases in the absence of PTS sugars. A recent study revealed that the dephosphorylated form of HPr binds and antagonizes the function of the antisigma factor Rsd. This anti-sigma factor sequesters the housekeeping sigma factor σ(70) to facilitate switching of the sigma subunit on RNA polymerase from σ(70) to the stress-responsive sigma factor σ(S) in stationary-phase cells. In this study, the structure of the complex of Rsd and HPr was determined at 2.1 Å resolution and revealed that the binding site for HPr on the surface of Rsd partly overlaps with that for σ(70). The localization of the phosphorylation site on HPr at the binding interface for Rsd explains why phosphorylation of HPr abolishes its binding to Rsd. The mutation of crucial residues involved in the HPr-Rsd interaction significantly influenced the competition between HPr and σ(70) for binding to Rsd both in vitro and in vivo. The results provide a structural basis for the linkage of global gene regulation to nutrient availability in the external environment.

MICROWAVE SPECTROSCOPY OF THE CALCIUM 4snf→4s(n+1)d, 4sng, 4snh, 4sni, AND 4snk TRANSITIONS

NASA Astrophysics Data System (ADS)

Nunkaew, Jirakan; Gallagher, Tom

2015-06-01

We use a delayed field ionization technique to observe the microwave transitions of calcium Rydberg states, from the 4snf states to the 4s(n+1)d, 4sng, 4snh, 4sni, and 4snk states for 18≤ n≤23. We analyze the observed intervals between the ℓ and (ℓ+1), ℓ≥5, states of the same n to determine the Ca^+ 4s dipole and quadrupole polarizabilities. We show that the adiabatic core polarization model is not adequate to extract the Ca^+ 4s dipole and quadrupole polarizabilities and a non adiabatic treatment is required. We use the non adiabatic core polarization model to determine the ionic dipole and quadrupole polarizabilities to be α_d=76.9(3);a_0^3 and α_q=206(9);a_0^5, respectively.

Syntheses and structures of [UO2( L)5](ClO4)2 and [U( L')4(H2O)4](ClO4)4 ( L is dimethylformamide, L' is N,N-dimethylcarbamide)

NASA Astrophysics Data System (ADS)

Serezhkin, V. N.; Vologzhanina, A. V.; Pushkin, D. V.; Astashkina, D. A.; Savchenkov, A. V.; Serezhkina, L. B.

2017-09-01

The reaction of aqueous solutions of uranyl perchlorate with selected organic amides was studied in the dark and under the sunlight. The complexes [UVIO2(C3H7NO)5](ClO4)2 ( I) and [UIV(C3H8N2O)4(H2O)4](ClO4)4 ( II), where C3H7NO is N,N-dimethylformamide ( Dmfa) and C3H8N2O is N,N-dimethylcarbamide ( a-Dmur), were studied by X-ray diffraction. Complex II and the complex UIV( s-Dmur)4(H2O)4(ClO4)4 ( III), where s-Dmur is N,N'-dimethylcarbamide, were studied by IR spectroscopy. Crystals I and II are composed of mononuclear [UO2( Dmfa)5]2+ and [U( Dmur)4(H2O)4]4+ groups as uranium-containing structural units belonging to the crystal-chemical groups AM 7 1 ( A = UVI, M 1 = O2- and Dmfa) and AM 8 1 ( A = UIV, M 1 = Dmur and H2O) of uranium complexes, respectively. The mononuclear uranium- containing complexes in the crystals of U(IV) and U(VI) perchlorates were found to obey the 14 neighbors rule.

Crystal structure of (E)-4-hy-droxy-N'-(3-meth-oxy-benzyl-idene)benzohydrazide.

PubMed

Chantrapromma, Suchada; Prachumrat, Patcharawadee; Ruanwas, Pumsak; Boonnak, Nawong; Kassim, Mohammad B

2016-09-01

The title compound, C 15 H 14 N 2 O 3 , crystallizes with two independent mol-ecules ( A and B ) in the asymmetric unit that differ in the orientation of the 3-meth-oxy-phenyl group with respect to the methyl-idenebenzohydrazide unit. The dihedral angles between the two benzene rings are 24.02 (10) and 29.30 (9)° in mol-ecules A and B , respectively. In mol-ecule A , the meth-oxy group is twisted slightly relative to its bound benzene ring, with a C meth-yl -O-C-C torsion angle of 14.2 (3)°, whereas it is almost co-planar in mol-ecule B , where the corresponding angle is -2.4 (3)°. In the crystal, the mol-ecules are linked by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, as well as by weak C-H⋯O inter-actions, forming sheets parallel to the bc plane. The N-H⋯O hydrogen bond and weak C-H⋯O inter-action link different mol-ecules ( A ⋯ B ) whereas both O-H⋯N and O-H⋯O hydrogen bonds link like mol-ecules ( A ⋯ A ) and ( B ⋯ B ). Pairs of inversion-related B mol-ecules are stacked approximately along the a axis by π-π inter-actions in which the distance between the centroids of the 3-meth-oxy-phenyl rings is 3.5388 (12) Å. The B mol-ecules also participate in weak C-H⋯π inter-actions between the 4-hy-droxy-phenyl and the 3-meth-oxy-phenyl rings.

From N=4 Galilean superparticle to three-dimensional non-relativistic N=4 superfields

NASA Astrophysics Data System (ADS)

Fedoruk, Sergey; Ivanov, Evgeny; Lukierski, Jerzy

2018-05-01

We consider the general N=4 , d = 3 Galilean superalgebra with arbitrary central charges and study its dynamical realizations. Using the nonlinear realization techniques, we introduce a class of actions for N=4 three-dimensional non-relativistic superparticle, such that they are linear in the central charge Maurer-Cartan one-forms. As a prerequisite to the quantization, we analyze the phase space constraints structure of our model for various choices of the central charges. The first class constraints generate gauge transformations, involving fermionic κ-gauge transformations. The quantization of the model gives rise to the collection of free N=4 , d = 3 Galilean superfields, which can be further employed, e.g., for description of three-dimensional non-relativistic N=4 supersymmetric theories.

N-2-Hydroxy-4-methoxyacetophenone- N'-4-nitrobenzoyl hydrazine: Synthesis and structural characterization

NASA Astrophysics Data System (ADS)

Bessy Raj, B. N.; Kurup, M. R. Prathapachandra

2007-04-01

A new aroyl hydrazone, N-2-hydroxy-4-methoxyacetophenone- N'-4-nitrobenzoyl hydrazine was prepared by the condensation reaction of 2-hydroxy-4-methoxyacetophenone and 4-nitrobenzoyl hydrazine. Characterization of the compound was done by elemental analysis and electronic, infrared and NMR spectral analyses. The complete structural assignment of the compound was done by NMR studies by using COSY homonuclear and HSQC heteronuclear techniques. The crystal and molecular structure was determined by single crystal X-ray diffraction studies: crystallized in the monoclinic system, space group P2 1/ n, Z = 4, a = 7.3343(9) Å, b = 20.3517(9) Å, c = 10.1375(5) Å, α = 90.00°, β = 95.735(7)° and γ = 90.00°. From the crystal structure, it is concluded that the compound exists as the keto isomer in the solid state. There is a completely extended conformation in the central part of the molecule C5 sbnd C8 dbnd N1 sbnd N2 sbnd C10 dbnd O2 with an E configuration at the double bond of the hydrazinic bridge.

Crystal structure of (4-cyano­pyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ4 N}zinc–4-cyano­pyridine (1/1)

PubMed Central

Nasri, Soumaya; Amiri, Nesrine; Turowska-Tyrk, Ilona; Daran, Jean-Claude; Nasri, Habib

2016-01-01

In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetra­phenyl­benzoate)porphyrinate and 4-cyano­pyridine, respectively], the ZnII cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn—N(pyrrole) bond length is 2.060 (6) Å and the Zn—N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Å from the N4C20 mean plane of the porphyrinate anion toward the 4-cyano­pyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex mol­ecules are linked together via weak C—H⋯N, C—H⋯O and C—H⋯π inter­actions, forming supra­molecular channels parallel to the c axis. The non-coordinating 4-cyano­pyridine mol­ecules are located in the channels and linked with the complex mol­ecules, via weak C—H⋯N inter­actions and π-π stacking or via weak C—H⋯O and C—H⋯π inter­actions. The non-coordinating 4-cyano­pyridine mol­ecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4). PMID:26958379

Theoretical and Experimental Studies of N,N-Dimethyl-N'-Picryl-4,4'-Stilbenediamine.

PubMed

Papper, Vladislav; Wu, Yuanyuan; Kharlanov, Vladimir; Sukharaharja, Ayrine; Steele, Terry W J; Marks, Robert S

2018-01-01

N,N-dimethyl-N'-picryl-4,4'-stilbenediamine (DMPSDA) was prepared, purified and crystallised in a form of black lustrous crystals, and its absorption and fluorescence spectra were recorded in cyclohexane, acetonitrile and dimethyl sulfoxide. Non-emissive intramolecular charge transfer state (ICT) was clearly observed in this molecule in all three solvents. Theoretical calculations demonstrating a betaine electronic structure of the trinitrophenyl group in the ground state of the molecule and a charge transfer nature of the long wavelength transition S 0  → S 1 supported the experimental observations of the ICT formation in the molecule.

Synthesis and Proapoptotic Activity on Cervical Cancer Cell of Ester Eugenol 1-(3-Methoxy-4-hydroxy)phenyl-2-propylmethanoate

NASA Astrophysics Data System (ADS)

Farid Rahman, Moh.; Nazhif Haykal, Muhammad; Andriani Siagian, Novi; Maiselina Sriepindonnta, Priscilla; Tampubolon, Norman Alexander

2018-01-01

Proapoptotic activity of ester eugenol,1-(3-methoxy-4-hydroxy)phenyl-2-propylmethanoat, which synthesized from eugenol is reported. Eugenol as starting material in the synthesis of ester eugenol was obtained from fractional distillation of clove oil with the yield of 70.66%. Synthesis of ester eugenol was camed out by addition-esterification reaction through reaction between eugenol and formic acid with mol ratio of 1:27 and reaction time for11 h. GC-MS analysis showed ester eugenol was afforded purity of 92.42% and the yield in of 93.34%. UV spectra of ester eugenol was observed the formation of carbonyl group at λmax 290 nm and supported by FT-IR analysis at 1714.60 cm-1 (carbonyl group), 1193.65 cm-1 (C-O-C ester group) and the absence of vynil group in eugenol structure at region 914.20 and 995.20 cm-1. Mass spectra showed ion molecule at m/z 210 was accordance with molecular weight of ester eugenol. Afterward, HeLa cell culture media was prepared for cervical cancer antiproliferative test. The result which showed in histogram indicated that LC50 of ester eugenol was reached at concentration below 0.01% while eugenol was up to 0.01% that observed cervical cancer cell apoptotic activity. LC50 value of ester eugenol was obtained at concentration 48.73 ppm. This research reported that natural product modified its structure has potency to cure cervical cancer.

Malate-Mediated Carbon Catabolite Repression in Bacillus subtilis Involves the HPrK/CcpA Pathway ▿ §

PubMed Central

Meyer, Frederik M.; Jules, Matthieu; Mehne, Felix M. P.; Le Coq, Dominique; Landmann, Jens J.; Görke, Boris; Aymerich, Stéphane; Stülke, Jörg

2011-01-01

Most organisms can choose their preferred carbon source from a mixture of nutrients. This process is called carbon catabolite repression. The Gram-positive bacterium Bacillus subtilis uses glucose as the preferred source of carbon and energy. Glucose-mediated catabolite repression is caused by binding of the CcpA transcription factor to the promoter regions of catabolic operons. CcpA binds DNA upon interaction with its cofactors HPr(Ser-P) and Crh(Ser-P). The formation of the cofactors is catalyzed by the metabolite-activated HPr kinase/phosphorylase. Recently, it has been shown that malate is a second preferred carbon source for B. subtilis that also causes catabolite repression. In this work, we addressed the mechanism by which malate causes catabolite repression. Genetic analyses revealed that malate-dependent catabolite repression requires CcpA and its cofactors. Moreover, we demonstrate that HPr(Ser-P) is present in malate-grown cells and that CcpA and HPr interact in vivo in the presence of glucose or malate but not in the absence of a repressing carbon source. The formation of the cofactor HPr(Ser-P) could be attributed to the concentrations of ATP and fructose 1,6-bisphosphate in cells growing with malate. Both metabolites are available at concentrations that are sufficient to stimulate HPr kinase activity. The adaptation of cells to environmental changes requires dynamic metabolic and regulatory adjustments. The repression strength of target promoters was similar to that observed in steady-state growth conditions, although it took somewhat longer to reach the second steady-state of expression when cells were shifted to malate. PMID:22001508

Synthesis and structure of the extended phosphazane ligand [(1,4-C6H4){N(μ-PN(t)Bu)2N(t)Bu}2](4).

PubMed

Sevilla, Raquel; Less, Robert J; García-Rodríguez, Raúl; Bond, Andrew D; Wright, Dominic S

2016-02-07

The reaction of the phenylene-bridged precursor (1,4-C6H4)[N(PCl2)2]2 with (t)BuNH2 in the presence of Et3N gives the new ligand precursor (1,4-C6H4)[N(μ-N(t)Bu)2(PNH(t)Bu)2]2, deprotonation of which with Bu2Mg gives the novel tetraanion [(1,4-C6H4){N(μ-N(t)Bu)2(PN(t)Bu)2}2](4-).

Bacillus subtilis mutant LicT antiterminators exhibiting enzyme I- and HPr-independent antitermination affect catabolite repression of the bglPH operon.

PubMed

Lindner, Cordula; Hecker, Michael; Le Coq, Dominique; Deutscher, Josef

2002-09-01

The Bacillus subtilis antiterminator LicT regulates the expression of bglPH and bglS, which encode the enzymes for the metabolism of aryl-beta-glucosides and the beta-glucanase BglS. The N-terminal domain of LicT (first 55 amino acids) prevents the formation of rho-independent terminators on the respective transcripts by binding to target sites overlapping these terminators. Proteins of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) regulate the antitermination activity of LicT by phosphorylating histidines in its two PTS regulation domains (PRDs). Phosphorylation at His-100 in PRD-1 requires the PTS proteins enzyme I and HPr and the phosphorylated permease BglP and inactivates LicT. During transport and phosphorylation of aryl-beta-glucosides, BglP is dephosphorylated, which renders LicT active and thus leads to bglPH and bglS induction. In contrast, phosphorylation at His-207 and/or His-269 in PRD-2, which requires only enzyme I and HPr, is absolutely necessary for LicT activity and bglPH and bglS expression. We isolated spontaneous licT mutants expressing bglPH even when enzyme I and HPr were absent (as indicated by the designation "Pia" [PTS-independent antitermination]). Introduced in a ptsHI(+) strain, two classes of licT(Pia) mutations could be distinguished. Mutants synthesizing LicT(Pia) antiterminators altered in PRD-2 still required induction by aryl-beta-glucosides, whereas mutations affecting PRD-1 caused constitutive bglPH expression. One of the two carbon catabolite repression (CCR) mechanisms operative for bglPH requires the rho-independent terminator and is probably prevented when LicT is activated by P approximately His-HPr-dependent phosphorylation in PRD-2 (where the prefix "P approximately " stands for "phospho"). During CCR, the small amount of P approximately His-HPr present in cells growing on repressing PTS sugars probably leads to insufficient phosphorylation at PRD-2 of LicT and therefore to reduced bglPH expression

Bacillus subtilis Mutant LicT Antiterminators Exhibiting Enzyme I- and HPr-Independent Antitermination Affect Catabolite Repression of the bglPH Operon

PubMed Central

Lindner, Cordula; Hecker, Michael; Le Coq, Dominique; Deutscher, Josef

2002-01-01

The Bacillus subtilis antiterminator LicT regulates the expression of bglPH and bglS, which encode the enzymes for the metabolism of aryl-β-glucosides and the β-glucanase BglS. The N-terminal domain of LicT (first 55 amino acids) prevents the formation of ρ-independent terminators on the respective transcripts by binding to target sites overlapping these terminators. Proteins of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) regulate the antitermination activity of LicT by phosphorylating histidines in its two PTS regulation domains (PRDs). Phosphorylation at His-100 in PRD-1 requires the PTS proteins enzyme I and HPr and the phosphorylated permease BglP and inactivates LicT. During transport and phosphorylation of aryl-β-glucosides, BglP is dephosphorylated, which renders LicT active and thus leads to bglPH and bglS induction. In contrast, phosphorylation at His-207 and/or His-269 in PRD-2, which requires only enzyme I and HPr, is absolutely necessary for LicT activity and bglPH and bglS expression. We isolated spontaneous licT mutants expressing bglPH even when enzyme I and HPr were absent (as indicated by the designation “Pia” [PTS-independent antitermination]). Introduced in a ptsHI+ strain, two classes of licT(Pia) mutations could be distinguished. Mutants synthesizing LicT(Pia) antiterminators altered in PRD-2 still required induction by aryl-β-glucosides, whereas mutations affecting PRD-1 caused constitutive bglPH expression. One of the two carbon catabolite repression (CCR) mechanisms operative for bglPH requires the ρ-independent terminator and is probably prevented when LicT is activated by P∼His-HPr-dependent phosphorylation in PRD-2 (where the prefix “P∼” stands for “phospho”). During CCR, the small amount of P∼His-HPr present in cells growing on repressing PTS sugars probably leads to insufficient phosphorylation at PRD-2 of LicT and therefore to reduced bglPH expression. In agreement with this concept

40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P... reporting. (1) The chemical substances identified as acetamide, N-[4-(pentyloxy)phenyl]- (PMN P-92-31), acetamide, N-[2-nitro-4-(pentyloxy)phenyl]- (PMN P-92-32), and acetamide, N-[2-amino-4-(pentyloxy)phenyl...

40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P... reporting. (1) The chemical substances identified as acetamide, N-[4-(pentyloxy)phenyl]- (PMN P-92-31), acetamide, N-[2-nitro-4-(pentyloxy)phenyl]- (PMN P-92-32), and acetamide, N-[2-amino-4-(pentyloxy)phenyl...

Achieving high strength and high ductility in magnesium alloy using hard-plate rolling (HPR) process

NASA Astrophysics Data System (ADS)

Wang, Hui–Yuan; Yu, Zhao–Peng; Zhang, Lei; Liu, Chun–Guo; Zha, Min; Wang, Cheng; Jiang, Qi–Chuan

2015-11-01

Magnesium alloys are highly desirable for a wide range of lightweight structural components. However, rolling Mg alloys can be difficult due to their poor plasticity, and the strong texture yielded from rolling often results in poor plate forming ability, which limits their further engineering applications. Here we report a new hard-plate rolling (HPR) route which achieves a large reduction during a single rolling pass. The Mg-9Al-1Zn (AZ91) plates processed by HPR consist of coarse grains of 30-60 μm, exhibiting a typical basal texture, fine grains of 1-5 μm and ultrafine (sub) grains of 200-500 nm, both of the latter two having a weakened texture. More importantly, the HPR was efficient in gaining a simultaneous high strength and uniform ductility, i.e., ~371 MPa and ~23%, respectively. The superior properties should be mainly attributed to the cooperation effect of the multimodal grain structure and weakened texture, where the former facilitates a strong work hardening while the latter promotes the basal slip. The HPR methodology is facile and effective, and can avoid plate cracking that is prone to occur during conventional rolling processes. This strategy is applicable to hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial application.

The Nitrification Inhibitor Methyl 3-(4-Hydroxyphenyl)Propionate Modulates Root Development by Interfering with Auxin Signaling via the NO/ROS Pathway1

PubMed Central

Liu, Yangyang; Wang, Ruling; Zhang, Ping

2016-01-01

Methyl 3-(4-hydroxyphenyl)propionate (MHPP) is a root exudate that functions as a nitrification inhibitor and as a modulator of the root system architecture (RSA) by inhibiting primary root (PR) elongation and promoting lateral root formation. However, the mechanism underlying MHPP-mediated modulation of the RSA remains unclear. Here, we report that MHPP inhibits PR elongation in Arabidopsis (Arabidopsis thaliana) by elevating the levels of auxin expression and signaling. MHPP induces an increase in auxin levels by up-regulating auxin biosynthesis, altering the expression of auxin carriers, and promoting the degradation of the auxin/indole-3-acetic acid family of transcriptional repressors. We found that MHPP-induced nitric oxide (NO) production promoted reactive oxygen species (ROS) accumulation in root tips. Suppressing the accumulation of NO or ROS alleviated the inhibitory effect of MHPP on PR elongation by weakening auxin responses and perception and by affecting meristematic cell division potential. Genetic analysis supported the phenotype described above. Taken together, our results indicate that MHPP modulates RSA remodeling via the NO/ROS-mediated auxin response pathway in Arabidopsis. Our study also revealed that MHPP significantly induced the accumulation of glucosinolates in roots, suggesting the diverse functions of MHPP in modulating plant growth, development, and stress tolerance in plants. PMID:27217493

Complete genomic sequences for hepatitis C virus subtypes 4b, 4c, 4d, 4g, 4k, 4l, 4m, 4n, 4o, 4p, 4q, 4r and 4t.

PubMed

Li, Chunhua; Lu, Ling; Wu, Xianghong; Wang, Chuanxi; Bennett, Phil; Lu, Teng; Murphy, Donald

2009-08-01

In this study, we characterized the full-length genomic sequences of 13 distinct hepatitis C virus (HCV) genotype 4 isolates/subtypes: QC264/4b, QC381/4c, QC382/4d, QC193/4g, QC383/4k, QC274/4l, QC249/4m, QC97/4n, QC93/4o, QC139/4p, QC262/4q, QC384/4r and QC155/4t. These were amplified, using RT-PCR, from the sera of patients now residing in Canada, 11 of which were African immigrants. The resulting genomes varied between 9421 and 9475 nt in length and each contains a single ORF of 9018-9069 nt. The sequences showed nucleotide similarities of 77.3-84.3 % in comparison with subtypes 4a (GenBank accession no. Y11604) and 4f (EF589160) and 70.6-72.8 % in comparison with genotype 1 (M62321/1a, M58335/1b, D14853/1c, and 1?/AJ851228) reference sequences. These similarities were often higher than those currently defined by HCV classification criteria for subtype (75.0-80.0 %) and genotype (67.0-70.0 %) division, respectively. Further analyses of the complete and partial E1 and partial NS5B sequences confirmed these 13 'provisionally assigned subtypes'.

Evidence of link between quorum sensing and sugar metabolism in Escherichia coli revealed via cocrystal structures of LsrK and HPr

PubMed Central

Eo, Yumi; Ma, Xiaochu; Stephens, Kristina; Jeong, Migyeong; Bentley, William E.

2018-01-01

Quorum sensing (QS), a bacterial process that regulates population-scale behavior, is mediated by small signaling molecules, called autoinducers (AIs), that are secreted and perceived, modulating a “collective” phenotype. Because the autoinducer AI-2 is secreted by a wide variety of bacterial species, its “perception” cues bacterial behavior. This response is mediated by the lsr (LuxS-regulated) operon that includes the AI-2 transporter LsrACDB and the kinase LsrK. We report that HPr, a phosphocarrier protein central to the sugar phosphotransferase system of Escherichia coli, copurifies with LsrK. Cocrystal structures of an LsrK/HPr complex were determined, and the effects of HPr and phosphorylated HPr on LsrK activity were assessed. LsrK activity is inhibited when bound to HPr, revealing new linkages between QS activity and sugar metabolism. These findings help shed new light on the abilities of bacteria to rapidly respond to changing nutrient levels at the population scale. They also suggest new means of manipulating QS activity among bacteria and within various niches. PMID:29868643

Unusual structural phase transition in [N(C2H5)4][N(CH3)4][ZnBr4

NASA Astrophysics Data System (ADS)

Krawczyk, Monika K.; Ingram, Adam; Cach, Ryszard; Czapla, Zbigniew; Czupiński, Olaf; Dacko, Sławomir; Staniorowski, Piotr

2018-04-01

The new hybrid organic-inorganic crystal [N(C2H5)4][N(CH3)4][ZnBr4] was grown and its physical properties and structural phase transition are presented. On the basis of thermal analysis (DSC (differential scanning calorimetry), DTA (differential thermal analysis), DTG), X-ray structural, dilatometric and dielectric studies as well as optical observation, the reversible first-order phase transition at 490/488 K on heating and cooling run, respectively, has been found. An appearance of domain structure of ferroelastic type gives evidence for an untypical lowering of crystal symmetry during the phase transition. At room temperature, the satisfying crystal structure solution was found in the tetragonal system, in the P?21m space group.

Tri- and pentacalix[4]pyrroles: synthesis, characterization and their use in the extraction of halide salts.

PubMed

Aydogan, Abdullah; Akar, Ahmet

2012-02-13

Calixpyrrole-based oligomeric compounds were synthesized by "click chemistry" from the corresponding alkyne- and azide-functionalized calix[4]pyrroles. Calix[4]pyrrole 3, possessing an alkyne functional group, was prepared through a mixed condensation of pyrrole with acetone and but-3-ynyl 4-oxopentanoate. Another alkyne-group-containing calix[4]pyrrole 5 was obtained by treatment of 4'-hydroxyphenyl-functionalized calixpyrrole 4 with propargyl bromide. Tetrakis(azidopentyl)-functionalized calix[4]pyrrole 7 was synthesized by reacting NaN(3) with tetrabromopentyltetraethylcalix[4]pyrrole 6, which was prepared through a condensation reaction of pyrrole and 7-bromohept-2-one. Oligomeric calixpyrrole compounds were found to be capable of extracting tetrabutylammonium chloride and fluoride salts from aqueous media. Extraction abilities of the oligomeric compounds were monitored by NMR and UV/Vis spectroscopy and thermogravimetric analysis. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Particle size reduction of Si3N4 with Si3N4 milling hardware

NASA Technical Reports Server (NTRS)

Herbell, T. P.; Freedman, M. R.; Kiser, J. D.

1986-01-01

The grinding of Si3N4 powder using reaction bonded Si3N4 attrition, vibratory, and ball mills with Si3N4 media was examined. The rate of particle size reduction and the change in the chemical composition of the powder were determined in order to compare the grinding efficiency and the increase in impurity content resulting from mill and media wear for each technique. Attrition and vibratory milling exhibited rates of specific surface area increase that were approximately eight times that observed in ball milling. Vibratory milling introduced the greatest impurity pickup.

Bottom-up substitution assembly of AuF4-n0,-+nPO3 (n = 1-4): a theoretical study of novel oxyfluoride hyperhalogen molecules and anions AuF4-n(PO3)n0,-

NASA Astrophysics Data System (ADS)

Yang, Yi-fan; Cui, Zhong-hua; Ding, Yi-hong

2014-06-01

Compounds with high electron affinity, i.e. superhalogens, have continued to attract chemists' attention, due to their potential importance in fundamental chemistry and materials science. It has now proven very effective to build up novel superhalogens with multi-positively charged centres, which are usually called 'hyperhalogens'. Herein, using AuF4- and PO3 as the model building blocks, we made the first attempt to design the Au,P-based hyperhalogen anions AuF4-n(PO3)n- (n = 1-4) at the B3LYP/6-311+G(d)&SDD and CCSD(T)/6-311+G(d)&SDD (single-point) levels (6-311+G(d) for O, F, P and SDD for Au). Notably, for all the considered Au,P systems, the ground state bears a dioxo-bonded structure with n ≤ 3, which is significantly more stable than the usually presumed mono-oxo-bonded one. Moreover, the clustering of the -PO3 moieties becomes energetically favoured for n ≥ 3. The ground states of AuP4O120,- are the first reported cage-like oxide hyperhalogens. Thus, the -PO3 moiety cannot be retained during the 'bottom-up' assembly. The vertical detachment energy (VDE) value of the most stable AuF4-n(PO3)n- (n = 1-4) ranges from 7.16 to 8.20 eV, higher than the VDE values of the corresponding building blocks AuF4- (7.08 eV) and PO3- (4.69 eV). The adiabatic detachment energy values of these four hyperhalogens exceed 6.00 eV. Possible generation routes for AuF4-n(PO3)n- (n = 1-4) were discussed. The presently designed oxyfluorides not only enriches the family of hyperhalogens, but also demonstrates the great importance of considering the structural transformation during the superhalogen → hyperhalogen design such as for the present Au-P based systems.

Poly(N-arylenebenzimidazole)s via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Jr., Joseph G. (Inventor)

1996-01-01

Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Crystal structure of di-μ-chlorido-bis-(chlorido-{N1,N1-diethyl-N4-[(pyridin-2-yl-κN)methyl-idene]benzene-1,4-di-amine-κN4}mercury(II)).

PubMed

Faizi, Md Serajul Haque; Dege, Necmi; Goleva, Kateryna

2017-06-01

The title dinuclear mercury(II) complex, [Hg 2 Cl 4 (C 16 H 19 N 3 ) 2 ], synthesized from the pyridine-derived Schiff base ( E )- N 1 , N 1 -diethyl- N 4 -[(pyridin-2-yl)methyl-idene]benzene-1,4-di-amine (DPMBD), has inversion symmetry. The five-coordinated Hg II atoms have distorted square-pyramidal stereochemistry comprising two N-atom donors from bidentate chelate BPMBD ligands and three Cl-atom donors, two bridging and one monodentate. The dihedral angle between the benzene and the pyridine rings in the BPMBD ligand is 7.55 (4)°. In the crystal, the dinuclear mol-ecules are linked by weak C-H⋯Cl hydrogen bonds, forming zigzag ribbons lying parallel to [001]. Also present in the structure are π-π inter-actions between benzene and pyridine rings [minimum ring-centroid separation = 3.698 (8) Å].

2-(4-Hy-droxy-phen-yl)-1H-benzimidazol-3-ium chloride monohydrate.

PubMed

González-Padilla, Jazmin E; Rosales-Hernández, Martha Cecila; Padilla-Martínez, Itzia I; García-Báez, Efren V; Rojas-Lima, Susana

2013-01-01

The title mol-ecular salt, C13H11N2O(+)·Cl(-)·H2O, crystallizes as a monohydrate. In the cation, the phenol and benzimidazole rings are almost coplanar, making a dihedral angle of 3.18 (4)°. The chloride anion and benzimidazole cation are linked by two N(+)-H⋯Cl(-) hydrogen bonds, forming chains propagating along [010]. These chains are linked through O-H⋯Cl hydrogen bonds involving the water mol-ecule and the chloride anion, which form a diamond core, giving rise to the formation of two-dimensional networks lying parallel to (10-2). Two π-π inter-actions involving the imidazolium ring with the benzene and phenol rings [centroid-centroid distances = 3.859 (3) and 3.602 (3) Å, respectively], contribute to this second dimension. A strong O-H⋯O hydrogen bond involving the water mol-ecule and the phenol substituent on the benzimidazole unit links the networks, forming a three-dimensional structure.

Anhydrous versus hydrated N4-substituted 1H-pyrazolo[3,4-d]pyrimidine-4,6-diamines: hydrogen bonding in two and three dimensions.

PubMed

Trilleras, Jorge; Quiroga, Jairo; Cobo, Justo; Marchal, Antonio; Nogueras, Manuel; Low, John N; Glidewell, Christopher

2008-10-01

Ten new N(4)-substituted 1H-pyrazolo[3,4-d]pyrimidine-4,6-diamines have been synthesized and the structures of nine of them are reported here, falling into two clear groups, those which are stoichiometric hydrates and those which crystallize in solvent-free forms. In each of N(4)-methyl-N(4)-phenyl-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine, C(12)H(12)N(6) (I), N(4)-cyclohexyl-N(4)-methyl-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine, C(12)H(18)N(6) (II), and N(4)-(3-chlorophenyl)-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine, C(11)H(9)ClN(6) (III), the molecules are linked into hydrogen-bonded sheets. The molecules of 2-{4-(6-amino-1H-pyrazolo[3,4-d]pyrimidin-4-yl)piperazin-1-yl}ethanol, C(11)H(17)N(7)O (IV), are linked into a three-dimensional framework, while the structure of N(4)-methyl-N(4)-(4-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine monohydrate, C(13)H(14)N(6) x H(2)O (V), is only two-dimensional despite the presence of five independent hydrogen bonds. The stoichiometric hemihydrates N(4)-ethyl-N(4)-phenyl-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine hemihydrate, C(13)H(14)N(6) x 0.5 H(2)O (VI) and N(4)-(4-methoxyphenyl)-N(4)-methyl-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine hemihydrate, C(13)H(14)N(6)O x 0.5 H(2)O (VII), exhibit remarkably similar sheet structures, despite different space groups and Z' values, Z' = 0.5 in C2/c for (VI) and Z' = 1 in P1 for (VII). N(4)-4-Benzyl-N(4)-phenyl-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine monohydrate, C(18)H(16)N(6) x H(2)O (VIII), crystallizes with Z' = 2 in P2(1)/n, and the four independent molecular components are linked into sheets by a total of 11 intermolecular hydrogen bonds. The sheet structure in {4-(pyrrolidin-1-yl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine} ethanol hemisolvate hemihydrate, C(9)H(12)N(6).0.5C(2)H(6)O x 0.5 H(2)O (IX), is built from the pyrimidine and water components only; it contains eight independent hydrogen bonds, and it very closely mimics the sheets in (VI) and (VII); the ethanol molecules are

N(4)-Methyl-N(4)-(2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine-ethanol-hydrazine (1/0.865/0.135): hydrogen-bonded ribbons containing four independent ring types.

PubMed

Trilleras, Jorge; Quiroga, Jairo; Cobo, Justo; Glidewell, Christopher

2009-06-01

N(4)-Methyl-N(4)-(2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidine-4,6-diamine crystallizes from ethanol as a mixed solvate, C(13)H(14)N(6).0.865C(2)H(6)O.0.135N(2)H(4), (I), where the hydrazine has been carried through from the initial preparation. Within the heterocyclic component, the 2-methylphenyl substituent is disordered over two sets of sites. There is an intramolecular C-H...pi(arene) hydrogen bond, which may control the molecular conformation of the heterocycle. The heterocyclic molecules are linked by two independent N-H...N hydrogen bonds in a chain containing two types of R(2)(2)(8) ring. The ethanol component is linked to this chain by a combination of O-H...N and N-H...O hydrogen bonds and the hydrazine component by two N-H...N hydrogen bonds, so generating two R(3)(3)(9) rings and thus forming a ribbon containing four distinct ring types.

Lignins : natural polymers from oxidative coupling of 4-hydroxyphenyl-propanoids

Treesearch

John Ralph; Knut Lundquist; Gosta Brunow; Fachuang Lu; Hoon Kim; Paul F. Schatz; Jane M. Marita; Ronald D. Hatfield; Sally A. Ralph; Jorgen Holst Christensen; Wout Boerjan

2004-01-01

Lignins are complex natural polymers resulting from oxidative coupling of, primarily, 4-hydroxyphenylpropanoids. An understanding of their nature is evolving as a result of detailed structural studies, recently aided by the availability of lignin-biosynthetic-pathway mutants and transgenics. The currently accepted theory is that the lignin polymer is formed by...

Particle-size reduction of Si3N4 powder with Si3N4 milling hardware

NASA Technical Reports Server (NTRS)

Herbell, T. P.; Freedman, M. R.; Kiser, J. D.

1986-01-01

The grinding of Si3N4 powder using reaction bonded Si3N4 attrition, vibratory, and ball mills with Si3N4 media was examined. The rate of particle size reduction and the change in the chemical composition of the powder were determined in order to compare the grinding efficiency and the increase in impurity content resulting from mill and media wear for each technique. Attrition and vibratory milling exhibited rates of specific surface area increase that were approximately eight times that observed in ball milling. Vibratory milling introduced the greatest impurity pickup.

Sequence-specific sup 1 H NMR resonance assignments of Bacillus subtilis HPr: Use of spectra obtained from mutants to resolve spectral overlap

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

Wittekind, M.; Klevit, R.E.; Reizer, J.

1990-08-07

On the basis of an analysis of two-dimensional {sup 1}H NMR spectra, the complete sequence-specific {sup 1}H NMR assignments are presented for the phosphocarrier protein HPr from the Gram-positive bacterium Bacillus subtilis. During the assignment procedure, extensive use was made of spectra obtained from point mutants of HPr in order to resolve spectral overlap and to provide verification of assignments. Regions of regular secondary structure were identified by characteristic patterns of sequential backbone proton NOEs and slowly exchanging amide protons. B subtilis HPr contains four {beta}-strands that form a single antiparallel {beta}-sheet and two well-defined {alpha}-helices. There are two stretchesmore » of extended backbone structure, one of which contains the active site His{sub 15}. The overall fold of the protein is very similar to that of Escherichia coli HPr determined by NMR studies.« less

Combustion Properties of Amino-Substituted Guanidinium 4,4',5,5'-Tetranitro-2,2'-biimidazolate(N4BIM) Salts

DOE PAGES

Tappan, Bryce C.; Chavez, David E.

2014-12-02

This paper describes the combustion properties of the amino-substituted guanidinium 4,4’,5,5’-tetranitro-2,2’-biimidazolate (N4BIM) series, including the bis-mono, di and triaminoguanidinium salts. These salts are of interest as propellant ingredient additives, and in particular, the bis-triaminoguanidinium salt of N4BIM displays excellent burn rate and combustion behavior. Our combustion studies have shown that TAGN4-BIM displays a fast burning rate and has the lowest pressure dependence exponent yet measured for a triaminoguanidinium salt.

4-hydroxyphenylacetic acid derivatives of inositol from dandelion (Taraxacum officinale) root characterised using LC-SPE-NMR and LC-MS techniques.

PubMed

Kenny, O; Smyth, T J; Hewage, C M; Brunton, N P; McLoughlin, P

2014-02-01

The combination of hyphenated techniques, LC-SPE-NMR and LC-MS, to isolate and identify minor isomeric compounds from an ethyl acetate fraction of Taraxacum officinale root was employed in this study. Two distinct fractions of 4-hydroxyphenylacetic acid derivatives of inositol were isolated and characterised by spectroscopic methods. The (1)H NMR spectra and MS data revealed two groups of compounds, one of which were derivatives of the di-4-hydroxyphenylacetic acid derivative of the inositol compound tetrahydroxy-5-[2-(4-hydroxyphenyl)acetyl] oxycyclohexyl-2-(4-hydroxyphenyl) acetate, while the other group consisted of similar tri-substituted inositol derivatives. For both fractions the derivatives of inositols vary in the number of 4-hydroxyphenylacetic acid groups present and their position and geometry on the inositol ring. In total, three di-substituted and three tri-substituted 4-hydroxyphenylacetic acid inositol derivates were identified for the first time along with a further two previously reported di-substituted inositol derivatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

Second-Nearest-Neighbor Effects upon N NMR Shieldings in Models for Solid Si 3N 4and C 3N 4

NASA Astrophysics Data System (ADS)

Tossell, J. A.

1997-07-01

NMR shifts are generally determined mainly by the nearest-neighbor environment of an atom, with fairly small changes in the shift arising from differences in the second-nearest-neighbor environment. Previous calculations on the (SiH3)3N molecule used as a model for the local environment of N in crystalline α- and β-Si3N4gave N NMR shieldings much larger than those measured in the solids and gave the wrong order for the shifts of the inequivalent N sites (e.g., N1 and N2 in β-Si3N4). We have now calculated the N NMR shieldings in larger molecular models for the N2 site of β-Si3N4and have found that the N2 shielding is greatly reduced when additional N1 atoms (second-nearest-neighbors to the central N2) are included. The calculated N2 shieldings (using the GIAO method with the 6-31G* basis set and 6-31G* SCF optimized geometries) are 288.1, 244.7, and 206.0 ppm for the molecules (SiH3)3N, Si6N5H15, and Si9N9H21(central N2), respectively, while the experimental shielding of N2 in β-Si3N4is about 155 ppm. Second-nearest-neighbor effects of only slightly smaller magnitude are calculated for the analog C molecules. At the same time, the effects of molecule size upon Si NMR shieldings and N electric field gradients are small. The local geometries at the N2-like Ns in C6N5H15and C9N9H21are calculated to be planar, consistent with the planar local geometry recently calculated for N in crystalline C3N4using density functional theory.

A Convenient, TiCl4/SnCl4-Mediated Synthesis of N-Phenyl or N-Aryl Benzamidines and N-Phenylpicolinamidines

PubMed Central

Patil, Umesh D.; Mahulikar, Pramod P.

2012-01-01

A new, TiCl4-or SnCl4-mediated, solvent-free method was developed for the synthesis of N-Aryl benzamidines and N-phenylpicolinamidines, in moderate-to-good yield, using suitable amines and nitriles as starting materials. PMID:24052858

The crystal structures of iron and cobalt pyridine (py)–sulfates, [Fe(SO4)(py)4]n and [Co3(SO4)3(py)11]n

PubMed Central

Pham, Duyen N. K.; Roy, Mrittika; Kreider-Mueller, Ava; Golen, James A.; Manke, David R.

2018-01-01

The solid-state structures of two metal–pyridine–sulfate compounds, namely catena-poly[[tetra­kis­(pyridine-κN)iron(II)]-μ-sulfato-κ2 O:O′], [Fe(SO4)(C5H5N)4]n, (1), and catena-poly[[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ2 O:O′-[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ3 O,O′:O′′-[tris­(pyridine-κN)cobalt(II)]-μ-sulfato-κ2 O:O′], [Co3(SO4)3(C5H5N)11]n, (2), are reported. The iron compound (1) displays a polymeric structure, with infinite chains of FeII atoms adopting octa­hedral N4O2 coordination environments that involve four pyridine ligands and two bridging sulfate ligands. The cobalt compound (2) displays a polymeric structure, with infinite chains of CoII atoms. Two of the three Co centers have an octa­hedral N4O2 coordination environment that involves four pyridine ligands and two bridging sulfate ligands. The third Co center has an octa­hedral N3O3 coordination environment that involves three pyridine ligands, and two bridging sulfate ligands with one sulfate chelating the cobalt atom.

Crystal growth of triphenylphosphine oxide 4-nitrophenol (TP4N) for nonlinear optical (NLO) applications

NASA Astrophysics Data System (ADS)

Pandian, Muthu Senthil; Karuppasamy, P.; Kamalesh, T.; Ramasamy, P.; Verma, Sunil

2018-04-01

The optically good quality organic single crystals of triphenylphosphine oxide 4-nitrophenol (TP4N) were successfully grown by slow evaporation solution technique (SEST) using methanol as solvent. The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. The optical transmittance, cut-off wavelength and band gap of the TP4N crystal were obtained by UV-Vis NIR spectrum analysis. The photoluminescence studies were carried out to find out the luminesce properties of TP4N single crystal. The photoconductivity studies reveal that the TP4N crystal has negative photoconductive nature. The third order nonlinear susceptibility (χ(3)) of TP4N crystal was evaluated using the Z-scan technique at 640 nm.

Absence of genotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one) and its potential chemoprevention against DNA damage using in vitro and in vivo assays

PubMed Central

2017-01-01

The chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one), or 2HMC, displays antileishmanial, antimalarial, and antioxidant activities. The aim of this study was to investigate the cytotoxic, genotoxic, mutagenic, and protective effects of 2HMC using the Ames mutagenicity test, the mouse bone marrow micronucleus test, and the comet assay in mice. In the assessment using the Ames test, 2HMC did not increase the number of His+ revertants in Salmonella typhimurium strains, demonstrating lack of mutagenicity. 2HMC showed no significant increase in micronucleated polychromatic erythrocyte frequency (MNPCE) in the micronucleus test, or in DNA strand breaks using the comet assay, evidencing absence of genotoxicity. Regarding cytotoxicity, 2HMC exhibited moderate cytotoxicity in mouse bone marrow cells by micronucleus test. 2HMC showed antimutagenic action in co-administration with the positive controls, sodium azide (SA) and 4-nitroquinoline-1-oxide (4NQO), in the Ames test. Co-administered and mainly pre-administered with cyclophosphamide (CPA), 2HMC caused a decrease in the frequency of MNPCE using the micronucleus test and in DNA strand breaks using the comet assay. Thus, 2HMC exhibited antimutagenic and antigenotoxic effects, displaying a DNA-protective effect against CPA, SA, and 4NQO carcinogens. In conclusion, 2HMC presented antimutagenic, antigenotoxic and moderate cytotoxic effects; therefore it is a promising molecule for cancer prevention. PMID:28207781

Absence of genotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one) and its potential chemoprevention against DNA damage using in vitro and in vivo assays.

PubMed

Lima, Débora Cristina da Silva; Vale, Camila Regina do; Véras, Jefferson Hollanda; Bernardes, Aline; Pérez, Caridad Noda; Chen-Chen, Lee

2017-01-01

The chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one), or 2HMC, displays antileishmanial, antimalarial, and antioxidant activities. The aim of this study was to investigate the cytotoxic, genotoxic, mutagenic, and protective effects of 2HMC using the Ames mutagenicity test, the mouse bone marrow micronucleus test, and the comet assay in mice. In the assessment using the Ames test, 2HMC did not increase the number of His+ revertants in Salmonella typhimurium strains, demonstrating lack of mutagenicity. 2HMC showed no significant increase in micronucleated polychromatic erythrocyte frequency (MNPCE) in the micronucleus test, or in DNA strand breaks using the comet assay, evidencing absence of genotoxicity. Regarding cytotoxicity, 2HMC exhibited moderate cytotoxicity in mouse bone marrow cells by micronucleus test. 2HMC showed antimutagenic action in co-administration with the positive controls, sodium azide (SA) and 4-nitroquinoline-1-oxide (4NQO), in the Ames test. Co-administered and mainly pre-administered with cyclophosphamide (CPA), 2HMC caused a decrease in the frequency of MNPCE using the micronucleus test and in DNA strand breaks using the comet assay. Thus, 2HMC exhibited antimutagenic and antigenotoxic effects, displaying a DNA-protective effect against CPA, SA, and 4NQO carcinogens. In conclusion, 2HMC presented antimutagenic, antigenotoxic and moderate cytotoxic effects; therefore it is a promising molecule for cancer prevention.

Scalar Casimir energies in M4>=N for even N

NASA Astrophysics Data System (ADS)

Kantowski, R.; Milton, Kimball A.

1987-01-01

We construct a Green's-function formalism for computing vacuum-fluctuation energies of scalar fields in 4+N dimensions, where the extra N dimensions are compactified into a hypersphere SN of radius a. In all cases a leading cosmological energy term ucosmo~aN/b4+N results. Here b is an ultraviolet cutoff at the Planck scale. In all cases an unambiguous Casimir energy is computed. For odd N these energies agree with those calculated by Candelas and Weinberg. For even N, the Casimir energy is logarithmically divergent: uCasimir~(αN/a4)ln(a/b). The coefficients αN are computed in terms of Bernoulli numbers.

Chemoprevention of hormone-dependent prostate cancer in the Wistar-Unilever rat.

PubMed

McCormick, D L; Rao, K V

1999-01-01

The high incidence and long latent period of prostate cancer make it an ideal target for chemoprevention. We have evaluated a series of agents for chemopreventive efficacy using a model in which hormone-dependent prostate cancers are induced in the Wistar-Unilever (WU) rat by sequential treatment with antiandrogen (cyproterone acetate), androgen (testosterone propionate), and direct-acting chemical carcinogen (N-methyl-N-nitrosourea), followed by chronic androgen stimulation (testosterone). This regimen reproducibly induces prostate cancers in high incidence, with no gross toxicity and a low incidence of neoplasia in the seminal vesicle and other non-target tissues. Dehydroepiandrosterone (DHEA) and 9-cis-retinoic acid (9-cis-RA) are the most active agents identified to date. DHEA inhibits prostate cancer induction both when chronic administration is begun prior to carcinogen exposure, and when administration is delayed until preneoplastic prostate lesions are present. 9-cis-RA is the most potent inhibitor of prostate carcinogenesis identified; a study to determine the efficacy of delayed administration of 9-cis-RA is in progress. Liarozole fumarate confers modest protection against prostate carcinogenesis, while N-(4-hydroxyphenyl)retinamide (fenretinide), alpha-difluoromethylornithine, oltipraz, DL-alpha-tocopherol acetate (vitamin E), and L-selenomethionine are inactive. Chemoprevention efficacy evaluations in the WU rat will support the identification of agents that merit study for prostate cancer chemoprevention in humans.

4-Bromo-N-(di-n-propyl-carbamothioyl)-benzamide.

PubMed

Binzet, Gün; Flörke, Ulrich; Külcü, Nevzat; Arslan, Hakan

2009-02-04

The synthesis of the title compound, C(14)H(19)BrN(2)OS, involves the reaction of 4-bromo-benzoyl chloride with potassium thio-cyanate in acetone followed by condensation of the resulting 4-bromo-benzoyl isothio-cyanate with di-n-propyl-amine. Typical thio-urea carbonyl and thio-carbonyl double bonds, as well as shortened C-N bonds, are observed in the title compound. The short C-N bond lengths in the centre of the mol-ecule reveal the effects of resonance in this part of the mol-ecule. The asymmetric unit of the title compound contains two crystallographically independent mol-ecules, A and B. There is very little difference between the bond lengths and angles of these mol-ecules. In mol-ecule B, one di-n-propyl group is twisted in a -anti-periplanar conformation with C-C-C-H = -179.1 (3)° and the other adopts a -synclinal conformation with C-C-C-H = -56.7 (4)°; in mol-ecule A the two di-n-propyl groups are twisted in + and -anti-periplanar conformations, with C-C-C-H = -179.9 (3) and 178.2 (3)°, respectively. In the crystal, the mol-ecules are linked into dimeric pairs via pairs of N-H⋯S hydrogen bonds.

ELOVL4 protein preferentially elongates 20:5n3 to very long chain PUFAs over 20:4n6 and 22:6n3[S

PubMed Central

Yu, Man; Benham, Aaron; Logan, Sreemathi; Brush, R. Steven; Mandal, Md Nawajes A.; Anderson, Robert E.; Agbaga, Martin-Paul

2012-01-01

We hypothesized that reduction/loss of very long chain PUFAs (VLC-PUFAs) due to mutations in the ELOngase of very long chain fatty acid-4 (ELOVL4) protein contributes to retinal degeneration in autosomal dominant Stargardt-like macular dystrophy (STGD3) and age-related macular degeneration; hence, increasing VLC-PUFA in the retina of these patients could provide some therapeutic benefits. Thus, we tested the efficiency of elongation of C20-C22 PUFA by the ELOVL4 protein to determine which substrates are the best precursors for biosynthesis of VLC-PUFA. The ELOVL4 protein was expressed in pheochromocytoma cells, while green fluorescent protein-expressing and nontransduced cells served as controls. The cells were treated with 20:5n3, 22:6n3, and 20:4n6, either individually or in equal combinations. Both transduced and control cells internalized and elongated the supplemented FAs to C22-C26 precursors. Only ELOVL4-expressing cells synthesized C28-C38 VLC-PUFA from these precursors. In general, 20:5n3 was more efficiently elongated to VLC-PUFA in the ELOVL4-expressing cells, regardless of whether it was in combination with 22:6n3 or with 20:4n6. In each FA treatment group, C34 and C36 VLC-PUFAs were the predominant VLC-PUFAs in the ELOVL4-expressing cells. In summary, 20:5n3, followed by 20:4n6, seems to be the best precursor for boosting the synthesis of VLC-PUFA by ELOVL4 protein. PMID:22158834

Novel N4 Bacteriophages Prevail in the Cold Biosphere.

PubMed

Zhan, Yuanchao; Buchan, Alison; Chen, Feng

2015-08-01

Coliphage N4 is a lytic bacteriophage discovered nearly half a century ago, and it was considered to be a "genetic orphan" until very recently, when several additional N4-like phages were discovered to infect nonenteric bacterial hosts. Interest in this genus of phages is stimulated by their unique genetic features and propagation strategies. To better understand the ecology of N4-like phages, we investigated the diversity and geographic patterns of N4-like phages by examining 56 Chesapeake Bay viral communities, using a PCR-clone library approach targeting a diagnostic N4-like DNA polymerase gene. Many new lineages of N4-like phages were found in the bay, and their genotypes shift from the lower to the upper bay. Interestingly, signature sequences of N4-like phages were recovered only from winter month samples, when water temperatures were below 4°C. An analysis of existing metagenomic libraries from various aquatic environments supports the hypothesis that N4-like phages are most prolific in colder waters. In particular, a high number of N4-like phages were detected in Organic Lake, Antarctica, a cold and hypersaline system. The prevalence of N4-like phages in the cold biosphere suggests these viruses possess yet-to-be-determined mechanisms that facilitate lytic infections under cold conditions. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

More N =4 superconformal bootstrap

NASA Astrophysics Data System (ADS)

Beem, Christopher; Rastelli, Leonardo; van Rees, Balt C.

2017-08-01

In this long overdue second installment, we continue to develop the conformal bootstrap program for N =4 superconformal field theories (SCFTs) in four dimensions via an analysis of the correlation function of four stress-tensor supermultiplets. We review analytic results for this correlator and make contact with the SCFT/chiral algebra correspondence of Beem et al. [Commun. Math. Phys. 336, 1359 (2015), 10.1007/s00220-014-2272-x]. We demonstrate that the constraints of unitarity and crossing symmetry require the central charge c to be greater than or equal to 3 /4 in any interacting N =4 SCFT. We apply numerical bootstrap methods to derive upper bounds on scaling dimensions and operator product expansion coefficients for several low-lying, unprotected operators as a function of the central charge. We interpret our bounds in the context of N =4 super Yang-Mills theories, formulating a series of conjectures regarding the embedding of the conformal manifold—parametrized by the complexified gauge coupling—into the space of scaling dimensions and operator product expansion coefficients. Our conjectures assign a distinguished role to points on the conformal manifold that are self-dual under a subgroup of the S -duality group. This paper contains a more detailed exposition of a number of results previously reported in Beem et al. [Phys. Rev. Lett. 111, 071601 (2013), 10.1103/PhysRevLett.111.071601] in addition to new results.

Synthesis, XRD single crystal structure analysis, vibrational spectral analysis, molecular dynamics and molecular docking studies of 2-(3-methoxy-4-hydroxyphenyl) benzothiazole

NASA Astrophysics Data System (ADS)

Sarau Devi, A.; Aswathy, V. V.; Sheena Mary, Y.; Yohannan Panicker, C.; Armaković, Stevan; Armaković, Sanja J.; Ravindran, Reena; Van Alsenoy, C.

2017-11-01

The vibrational spectra and corresponding vibrational assignments of 2-(3-methoxy-4-hydroxyphenyl)benzothiazole is reported. Single crystal XRD data of the title compound is reported and the orientation of methoxy group is cis to nitrogen atom of the thiazole ring. The phenyl ring breathing modes of the title compound are assigned at 1042 and 731 cm-1 theoretically. The charge transfer within the molecule is studied using frontier molecular orbital analysis. The chemical reactivity descriptors are calculated theoretically. The NMR spectral data predicted theoretically are in good agreement with the experimental data. The strong negative region spread over the phenyl rings, nitrogen atom and oxygen atom of the hydroxyl group in the MEP plot is due to the immense conjugative and hyper conjugative resonance charge delocalization of π-electrons. Molecule sites prone to electrophilic attacks have been determined by analysis of ALIE surfaces, while Fukui functions provided further insight into the local reactivity properties of title molecule. Autoxidation properties have been investigated by calculation of bond dissociation energies (BDEs) of hydrogen abstraction, while BDEs of the rest of the single acyclic bonds were valuable for the further investigation of degradation properties. Calculation of radial distribution functions was performed in order to determine which atoms of the title molecule have pronounced interactions with water molecules. The title compound forms a stable complex with aryl hydrocarbon receptor and can be a lead compound for developing new anti-tumor drug. Antimicrobial properties of the title compound was screened against one bacterial culture Escherchia coli and four fungal cultures viz., Aspergillus niger, Pencillum chrysogenum, Saccharomyces cerevisiae and Rhyzopus stolonifer.

Role of N-acetyltransferase 2 acetylation polymorphism in 4, 4'-methylene bis (2-chloroaniline) biotransformation.

PubMed

Hein, David W; Zhang, Xiaoyan; Doll, Mark A

2018-02-01

Arylamine N-acetyltransferase 1 (NAT1) and 2 (NAT2) catalyze the acetylation of arylamine carcinogens. Single nucleotide polymorphisms in the NAT2 coding exon present in NAT2 haplotypes encode allozymes with reduced N-acetyltransferase activity towards the N-acetylation of arylamine carcinogens and the O-acetylation of their N-hydroxylated metabolites. NAT2 acetylator phenotype modifies urinary bladder cancer risk following exposures to arylamine carcinogens such as 4-aminobiphenyl. 4, 4'-methylene bis (2-chloroaniline) (MOCA) is a Group 1 carcinogen for which a role of the NAT2 acetylation polymorphism on cancer risk is unknown. We investigated the role of NAT2 and the genetic acetylation polymorphism on both MOCA N-acetylation and N-hydroxy-MOCA O-acetylation. MOCA N-acetylation exhibited a robust gene dose response in rabbit liver cytosol and in cryopreserved human hepatocytes derived from individuals of rapid, intermediate and slow acetylator NAT2 genotype. MOCA exhibited about 4-fold higher affinity for recombinant human NAT2 than NAT1. Recombinant human NAT2*4 (reference) and 15 variant recombinant human NAT2 allozymes catalyzed both the N-acetylation of MOCA and the O-acetylation of N-hydroxy-MOCA. Human NAT2 5, NAT2 6, NAT2 7 and NAT2 14 allozymes catalyzed MOCA N-acetylation and N-hydroxy-O-acetylation at rates much lower than the reference NAT2 4 allozyme. In conclusion, our results show that NAT2 acetylator genotype has an important role in MOCA metabolism and suggest that risk assessments related to MOCA exposures consider accounting for NAT2 acetylator phenotype in the analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

PubMed

Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

2003-08-25

Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3

Rhodium(I)-Complexes Catalyzed 1,4-Conjugate Addition of Arylzinc Chlorides to N-Boc-4-pyridone.

PubMed

Guo, Fenghai; McGilvary, Matthew A; Jeffries, Malcolm C; Graves, Briana N; Graham, Shekinah A; Wu, Yuelin

2017-05-01

Rhodium(I)-complexes catalyzed the 1,4-conjugate addition of arylzinc chlorides to N -Boc-4-pyridone in the presence of chlorotrimethylsilane (TMSCl). A combination of [RhCl(C₂H₄)₂]₂ and BINAP was determined to be the most effective catalyst to promote the 1,4-conjugate addition reactions of arylzinc chlorides to N -Boc-4-pyridone. A broad scope of arylzinc reagents with both electron-withdrawing and electron-donating substituents on the aromatic ring successfully underwent 1,4-conjugate addition to N -Boc-4-pyridone to afford versatile 1,4-adducts 2-substituted-2,3-dihydropyridones in good to excellent yields (up to 91%) and excellent ee (up to 96%) when ( S )-BINAP was used as chiral ligand.

Genetic characterization of avian influenza subtype H4N6 and H4N9 from live bird market, Thailand

USDA-ARS?s Scientific Manuscript database

A one year active surveillance program for influenza A viruses among avian species in a live-bird market (LBM) in Bangkok, Thailand was conducted in 2009. Out of 970 samples collected, influenza A virus subtypes H4N6 (n=2) and H4N9 (n=1), were isolated from healthy Muscovy ducks. All three viruses w...

Heats of Formation for Cyclic C4Fn, n=4-8, and their Cations

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Ricca, Alessandra; Arnold, James (Technical Monitor)

2000-01-01

Heats of formation for cyclic C4F8 and C4F8+ are determined at the G3MP2 level. The several decomposition pathways are investigated. The calculations confirm that C4F8+ rearranges and its decomposition is responsible for both the C2F4+ and C3F5+ species observed in experiment. The heats of formation are presented for C4Fn and C4Fn+, n = 4-8.

catena-Poly[[bis­[4-(dimethyl­amino)­pyridine-κN 1]cobalt(II)]-di-μ-azido-κ4 N 1:N 3

PubMed Central

Guenifa, Fatiha; Zeghouan, Ouahida; Hadjadj, Nasreddine; Bendjeddou, Lamia; Merazig, Hocine

2013-01-01

The title layered polymer, [Co(N3)2(C7H10N2)2]n, contains CoII, azide and 4-(dimethyl­amino)­pyridine (4-DMAP) species with site symmetries m2m, 2 and m, respectively. The Co2+ ion adopts an octa­hedral coordination geometry in which four N atoms from azide ligands lie in the equatorial plane and two 4-DMAP N atoms occupy the axial positions. The CoII atoms are connected by two bridging azide ligands, resulting in a chain parallel to the c axis. PMID:23476514

Metabolism of 4-N-Hydroxy-Cytidine in Escherichia coli

PubMed Central

Trimble, R. B.; Maley, Frank

1971-01-01

4-N-hydroxy-cytidine was found to substitute for uridine as a pyrimidine supplement for the growth of Escherichia coli Bu−. Measurement of the incorporation of 4-N-hydroxy-cytidine-2-14C into ribonucleic acid and deoxyribonucleic acid revealed that this compound was converted to cytidine or uridine before utilization. Two pathways for metabolism were considered: (i) the reduction of 4-N-hydroxy-cytidine to cytidine followed by deamination, (ii) the direct hydrolysis of hydroxylamine from 4-N-hydroxy-cytidine to yield uridine. A threefold increase in cytidine (deoxycytidine) deaminase (EC 3.5.4.5) activity, when the cells were grown on 4-N-hydroxy-cytidine, suggested the involvement of this enzyme. More direct proof was obtained by purifying the deaminase 185-fold and finding that it released hydroxylamine from 4-N-hydroxy-cytidine at one-fiftieth the rate at which ammonia was removed from cytidine. This result is consistent with the slower rate of growth of the Bu− cells on 4-N-hydroxy-cytidine than cytidine and suggests that the second pathway is the major route for utilization of this compound. PMID:4941553

X-ray diffraction analysis of 4- and 4'-substituted C n H2 n + 1O-C6H3(OH)-CH=N-C6H4-C m H2 m + 1 ( n/ m = 2/1 and 3/4) salicylideneanilines

NASA Astrophysics Data System (ADS)

Kuz'mina, L. G.; Navasardyan, M. A.; Mikhailov, A. A.

2017-11-01

X-ray diffraction study of two crystalline modifications of C2H5O-C6H3(OH)-CH=N-C6H4-CH3 ( 1a, sp. gr. P21/ n, and 1b, sp. gr. C2/c) and C3H7O-C6H3(OH)-CH=N-C6H4-C4H9 ( 2, sp. gr. P212121) has been performed. The 1a crystal structure contains two independent molecules. The molecules are conformationally nonrigid with respect to the mutual rotation of benzene rings; the dihedral angles between their planes are 29.19° and 26.00° in the independent molecules of 1a, 18.72° in the molecule of 1b, and 50.35° in the molecule of 2. The crystal packing of the compounds is discussed.

Superconductivity at 33-37 K in A L n2Fe4As4O2 (A =Kand Cs;L n =lanthanides)

NASA Astrophysics Data System (ADS)

Wu, Si-Qi; Wang, Zhi-Cheng; He, Chao-Yang; Tang, Zhang-Tu; Liu, Yi; Cao, Guang-Han

2017-09-01

We have synthesized ten iron oxyarsenides, K L n2Fe4As4O2 (L n =Gd,Tb,Dy, and Ho) and Cs L n2Fe4As4O2 (L n =Nd,Sm,Gd,Tb,Dy, and Ho) , with the aid of the lattice-match approach. The resultant compounds possess hole-doped conducting double FeAs layers [AFe4As4] 2 - that are separated by the insulating [Ln2O2] 2 + slabs. Measurements of electrical resistivity and dc magnetic susceptibility demonstrate bulk superconductivity at Tc=33 -37 K. We find that Tc correlates with the axial ratio c /a for all 12442-type superconductors discovered. Also, Tc tends to increase with the lattice mismatch, implying that lattice instability plays a role in the enhancement of superconductivity.

Tautomerism in o-hydroxyanilino-1,4-naphthoquinone derivatives: Structure, NMR, HPLC and density functional theoretic investigations

NASA Astrophysics Data System (ADS)

Bhand, Sujit; Patil, Rishikesh; Shinde, Yogesh; Lande, Dipali N.; Rao, Soniya S.; Kathawate, Laxmi; Gejji, Shridhar P.; Weyhermüller, Thomas; Salunke-Gawali, Sunita

2016-11-01

Structure and spectral characteristics of 'Ortho' ((E)-4-hydroxy-2-(2‧-(4‧-R)-hydroxyphenyl)-imino)-naphthalen-1(2H)-one) and 'para' (2-(2‧-(4‧-R)-hydroxyphenyl)-amino)-1,4-naphthoquinone) tautomers of o-hydroxyanilino-1,4-naphthoquinone derivatives (Rdbnd H, 1A; sbnd CH3, 2A; and -Cl, 3A) are investigated using the 1H, 13C, DEPT, gDQCOSY, gHSQCAD NMR, HPLC, cyclic voltammetry techniques combined with the density functional theory. The compound 2A crystallizes in monoclinic space group P21/c. wherein the polymer chain is facilitated via Osbnd H⋯O and Csbnd H⋯O intermolecular hydrogen bonding. Marginal variations in bond distances in quinonoid and aminophenol moieties render structural flexibility to these compounds those in solution exist as exist in 'ortho - para' tautomers. 1H and 13C NMR spectra in DMSO-d6 showed two sets of peaks in all compounds; whereas only the para tautomer of for 1A and 2A, the para tautomer is predominant in CD3CN solution. Further the ortho-para interconversion is accompanied by a large up-field signals for C(3)sbnd H(3) in their 1H and 13C NMR spectra. These inferences are corroborated by the density functional theoretic calculations.

CeVO4 nanofibers hybridized with g-C3N4 nanosheets with enhanced visible-light-driven photocatalytic activity

NASA Astrophysics Data System (ADS)

Li, Li; Wang, Haoran; Wang, Xiong

2018-01-01

The g-C3N4/CeVO4 composites were successfully synthesized by hybridizing CeVO4 nanofibers with g-C3N4 nanosheets. The photocatalytic activity of g-C3N4/CeVO4 composites was evaluated for the photodegradation of methylene blue under visible light irradiation. Among them, the 50 wt% g-C3N4/CeVO4 composites presented the highest photocatalytic activity, about 2 and 3.2 times higher than those of CeVO4 and g-C3N4, respectively. The improved catalytic activity was owed to the hybridization, which facilitated the rapid separation of photoinduced carriers and enhanced the visible light harvesting. A possible photocatalytic mechanism was proposed.

Elastic scattering of 8He on 4He and 4 n system

NASA Astrophysics Data System (ADS)

Wolski, R.; Sidorchuk, S. I.; Ter-Akopian, G. M.; Fomichev, A. S.; Rodin, A. M.; Stepantsov, S. V.; Mittig, W.; Roussel-Chomaz, P.; Savajols, H.; Alamanos, N.; Auger, F.; Lapoux, V.; Raabe, R.; Tchuvil'sky, Yu. M.; Rusek, K.

2003-07-01

Elastic scattering of a 26A MeV beam of 8He on a gaseous helium target has been studied. In spite of efforts made for the observation of backward angle enhancement only upper limits could be obtained for the elastic scattering cross section at backward angles. The angular distribution of 8He nuclei scattered to CM 20°-80° was was analyzed in terms of a phenomenological Optical Model. Possible contributions from transfer reactions were estimated. The DWBA calculations indicate that the two step 2n transfer is more important than the one step 4n transfer. The transfer reaction d( 8He, 6Li)4n is discussed in terms of possible tests of a four-neutron system.

Efficient water disinfection with Ag2WO4-doped mesoporous g-C3N4 under visible light.

PubMed

Li, Yi; Li, Yanan; Ma, Shuanglong; Wang, Pengfei; Hou, Qianlei; Han, Jingjing; Zhan, Sihui

2017-09-15

Ag 2 WO 4 /g-C 3 N 4 composite photocatalyst was synthesized by polymerization of thiourea and ammonia chloride combined with the deposition-precipitation method, which was applied as an efficient visible-light driven photocatalyst for inactivating Escherichia coli (E. coli). The physicochemical properties of these photocatalysts were systematically characterized by various techniques such as SEM, TEM, XRD, FT-IR, BET, UV-vis DRS and PL. The synthesized photocatalysts exhibited outstandingly enhanced photocatalytic disinfection efficiency compared with that of pure g-C 3 N 4 and Ag 2 WO 4 under visible light. Furthermore, the optimal mass ratio of the Ag 2 WO 4 to g-C 3 N 4 was 5wt%, and a number of live bacteria could be completely inactivated with Ag 2 WO 4 (5%)/g-C 3 N 4 (100μg/mL) after 90min under visible light irradiation. The high disinfection efficiency is due to the synergetic effect between g-C 3 N 4 and Ag 2 WO 4 , including a good distribution of Ag 2 WO 4 particles on the surface of g-C 3 N 4 and an improved separation rate of photogenerated electron-hole pairs. The enhanced disinfection mechanism was also investigated using photogenerated current densities and electrochemical impedance spectroscopy (EIS). Considering the bulk availability and excellent disinfection activity of Ag 2 WO 4 /g-C 3 N 4 composite, it is a promising solar-driven photocatalyst for cleaning the microbial contaminated water. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR 721.10164 - Benzenecarboximidamide, N-hydroxy-4-nitro-.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenecarboximidamide, N-hydroxy-4... Specific Chemical Substances § 721.10164 Benzenecarboximidamide, N-hydroxy-4-nitro-. (a) Chemical substance... benzenecarboximidamide, N-hydroxy-4-nitro- (PMN P-08-36; CAS No. 1613-86-1) is subject to reporting under this section...

40 CFR 721.10164 - Benzenecarboximidamide, N-hydroxy-4-nitro-.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenecarboximidamide, N-hydroxy-4... Specific Chemical Substances § 721.10164 Benzenecarboximidamide, N-hydroxy-4-nitro-. (a) Chemical substance... benzenecarboximidamide, N-hydroxy-4-nitro- (PMN P-08-36; CAS No. 1613-86-1) is subject to reporting under this section...

[Seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value in rainwater in Yangtze River Delta].

PubMed

Xie, Ying-Xin; Zhang, Shu-Li; Zhao, Xu; Xiong, Zheng-Qin; Xing, Guang-Xi

2008-09-01

By using a customized manual rainwater sampler made of polyvinyl chloride plastic, the molar ratio of NH4(+) -N/NO3(-) -N and the natural 15N abundance of NH4(+) (delta 15 NH4(+) in rainwater was monitored all year round from June 2003 to July 2005 at three observation sites (Changshu, Nanjing, and Hangzhou) in the Yangtze River Delta. The results indicated that at the three sites, the NH4(+) -N/NO3(-) -N ratio and the delta 15 NH4(+) value in rainwater had the similar seasonal variation trend, being more obvious in Changshu (rural monitoring type) site than in Nanjing (urban monitoring type) and Hangzhou (urban-rural monitoring type) sites. The NH4(+) -N/NO3(-) -N ratio peaked from early June to early August, declined gradually afterwards, and reached the bottom in winter; while the delta 15 NH4(+) value was negative from late June to mid-August, turned positive from late August to mid or late November, became negative again when winter dominated from December to March, but turned positive again in next May and negative again in next July. These seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value were found in relation to the application of chemical nitrogen fertilizers during different crop growth periods, and also, the alternation of seasons and the NH3 volatilization from other NH3 emission sources (including excrements of human and animals, nitrogen- polluted water bodies, and organic nitrogen sources, etc.), which could be taken as an indicator of defining the sources and form composition of NH4(+) in atmospheric wet deposition and the intensity of various terrestrial NH3 emission sources.

Structure and magnetization of Co4N thin film

NASA Astrophysics Data System (ADS)

Pandey, Nidhi; Gupta, Mukul; Gupta, Rachana; Rajput, Parasmani; Stahn, Jochen

2018-02-01

In this work, we studied the local structure and the magnetization of Co4N thin films deposited by a reactive dc magnetron sputtering process. The interstitial incorporation of N atoms in a fcc Co lattice is expected to expand the structure. This expansion yields interesting magnetic properties e.g. a larger magnetic moment (than Co) and a very high value of spin polarization ratio in Co4N . By optimizing the growth conditions, we prepared Co4N film having lattice parameter close to its theoretically predicted value. The N concentration was measured using secondary ion mass spectroscopy. Detailed magnetization measurements using bulk magnetization method and polarized neutron reflectivity confirm that the magnetic moment of Co in Co4N is higher than that of Co.

Crystal structures of three co-crystals of 1,2-bis-(pyridin-4-yl)ethane with 4-alk-oxy-benzoic acids: 4-eth-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), 4-n-propoxybenzoic acid-1,2-bis(pyridin-4-yl)ethane (2/1) and 4-n-but-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1).

PubMed

Tabuchi, Yohei; Gotoh, Kazuma; Ishida, Hiroyuki

2015-11-01

The crystal structures of three hydrogen-bonded co-crystals of 4-alk-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), namely, 2C9H10O3·C12H12N2, (I), 2C10H12O3·C12H12N2, (II), and 2C11H14O3·C12H12N2, (III), have been determined at 93, 290 and 93 K, respectively. In (I), the asymmetric unit consists of one 4-eth-oxy-benzoic acid mol-ecule and one half-mol-ecule of 1,2-bis-(pyridin-4-yl)ethane, which lies on an inversion centre. In (II) and (III), the asymmetric units each comprise two crystallographically independent 4-alk-oxy-benzoic acid mol-ecules and one 1,2-bis-(pyridin-4-yl)ethane mol-ecule. In each crystal, the two components are linked by O-H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1unit of the acid and the base. Similar to the structure of 2:1 unit of (I), the units of (II) and (III) adopt nearly pseudo-inversion symmetry. The 2:1 units of (I), (II) and (III) are linked via C-H⋯O hydrogen bonds, forming tape structures.

Synthesis of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction with enhanced photocatalytic performance

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

He, Peizhi; Song, Limin; Zhang, Shujuan, E-mail: songlmnk@sohu.com

2014-03-01

Graphical abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The results show that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} possesses a much higher activity for the decomposition of RhB than that of the pure Ag{sub 3}PO{sub 4} particles. The most mechanism is that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst can efficiently separate the photogenerated electron–hole pairs, enhancing the photocatalytic activity of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} composites. - Highlights: • g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction showed much higher activity than that of Ag{sub 3}PO{sub 4}. • The high activitymore » could be attributed to g-C{sub 3}N{sub 4} for modifying Ag{sub 3}PO{sub 4}. • More ·OH radicals may be significant reason to improve Ag{sub 3}PO{sub 4} activity. - Abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UV–vis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} decomposed RhB more effectively than the pure Ag{sub 3}PO{sub 4} particles did, and 2 wt.% g-C{sub 3}N{sub 4} had the highest activity. Furthermore, 2 wt.% g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} degraded high-concentration RhB more potently than unmodified Ag{sub 3}PO{sub 4} did, probably because g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electron–hole pairs.« less

4,4′-Bipyridinium bis(perchlorate)–4-aminobenzoic acid–4,4′-bipyridine–water (1/4/2/2)

PubMed Central

Meng, Qun-Hui; Han, Lu; Hou, Jian-Dong; Luo, Yi-Fan; Zeng, Rong-Hua

2009-01-01

In the structure of the title compound, C10H10N2 2+·2ClO4 −·4C7H7NO2·2C10H8N2·2H2O, the 4,4′-bipyridinium cation has a crystallographically imposed centre of symmetry. The cation is linked by N—H⋯N hydrogen bonds to adjacent 4,4′-bipyridine mol­ecules, which in turn inter­act via O—H⋯N hydrogen bonds with 4-amino­benzoic acid mol­ecules, forming chains running parallel to [30]. The chains are further connected into a three-dimensional network by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions involving the perchlorate anion, the water mol­ecules and the 4-amino­benzoic acid mol­ecules. In addition, π–π stacking inter­actions with centroid–centroid distances ranging from 3.663 (6) to 3.695 (6) Å are present. The O atoms of the perchlorate anion are disordered over two sets of positions, with refined site occupancies of 0.724 (9) and 0.276 (9). PMID:21581593

Ti4O7/g-C3N4 visible light photocatalytic performance on hypophosphite oxidation: Effect of annealing temperature

NASA Astrophysics Data System (ADS)

Guan, Wei; Sun, Gaoge; Yin, Lei; Zhang, Zhenghua; Tian, Shichao

2018-03-01

The oxidation of hypophosphite to phosphate is the key to recover the phosphorus resource from the hypophosphite wastewater. In the present work, Ti4O7/g-C3N4 composites were synthesized at two different temperatures (100 and 160 °C) and their performance on photocatalytic oxidation of hypophosphite under visible light irradiation and the corresponding mechanism were evaluated. A hydrolysis method using g-C3N4 and Ti4O7 was applied to synthesize the Ti4O7/g-C3N4 composites with their hybrid structure and morphology confirmed by XRD, SEM and XPS. The annealing temperature significantly affected the photocatalytic performance of Ti4O7/g-C3N4 that the 160-Ti4O7/g-C3N4 composite (fabricated at 160 °C) showed the highest oxidation efficiency of hypophosphite of 81% and the highest photocatalytic oxidation rate of 0.467 h-1 comparing with the 100-Ti4O7/g-C3N4 composite (fabricated at 100 °C) and pure g-C3N4. The enhanced photocatalytic performance of 160-Ti4O7/g-C3N4 could be ascribed to the effective charge separation and enhanced photoabsorption efficiency. Additionally, electron spin resonance (ESR) results showed that hydroxyl radicals and superoxide anion radicals were mainly responsible to the oxidation of hypophosphite with superoxide anion radicals accounting for a more significant contribution. Moreover, Ti4O7/g-C3N4 photocatalysts showed the remarkable stability in the repetitive experiments.

N =4 supersymmetric mechanics on curved spaces

NASA Astrophysics Data System (ADS)

Kozyrev, Nikolay; Krivonos, Sergey; Lechtenfeld, Olaf; Nersessian, Armen; Sutulin, Anton

2018-04-01

We present N =4 supersymmetric mechanics on n -dimensional Riemannian manifolds constructed within the Hamiltonian approach. The structure functions entering the supercharges and the Hamiltonian obey modified covariant constancy equations as well as modified Witten-Dijkgraaf-Verlinde-Verlinde equations specified by the presence of the manifold's curvature tensor. Solutions of original Witten-Dijkgraaf-Verlinde-Verlinde equations and related prepotentials defining N =4 superconformal mechanics in flat space can be lifted to s o (n )-invariant Riemannian manifolds. For the Hamiltonian this lift generates an additional potential term which, on spheres and (two-sheeted) hyperboloids, becomes a Higgs-oscillator potential. In particular, the sum of n copies of one-dimensional conformal mechanics results in a specific superintegrable deformation of the Higgs oscillator.

Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

PubMed Central

2011-01-01

Background In plants, nitrate (NO3-) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+) nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4+ (aq) which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Results Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that transports N in the

Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants.

PubMed

Ariz, Idoia; Cruz, Cristina; Moran, Jose F; González-Moro, María B; García-Olaverri, Carmen; González-Murua, Carmen; Martins-Loução, Maria A; Aparicio-Tejo, Pedro M

2011-05-16

In plants, nitrate (NO3-) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+) nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4+ (aq) which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that transports N in the molecular form and is associated with

Ti4O7/g-C3N4 Visible Light Photocatalytic Performance on Hypophosphite Oxidation: Effect of Annealing Temperature

PubMed Central

Guan, Wei; Sun, Gaoge; Yin, Lei; Zhang, Zhenghua; Tian, Shichao

2018-01-01

The oxidation of hypophosphite to phosphate is the key to recover the phosphorus resource from the hypophosphite wastewater. In the present work, Ti4O7/g-C3N4 composites were synthesized at two different temperatures (100 and 160°C) and their performance on photocatalytic oxidation of hypophosphite under visible light irradiation and the corresponding mechanism were evaluated. A hydrolysis method using g-C3N4 and Ti4O7 was applied to synthesize the Ti4O7/g-C3N4 composites with their hybrid structure and morphology confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS). The annealing temperature significantly affected the photocatalytic performance of Ti4O7/g-C3N4 that the 160-Ti4O7/g-C3N4 composite (fabricated at 160°C) showed the highest oxidation efficiency of hypophosphite of 81% and the highest photocatalytic oxidation rate of 0.467 h−1 comparing with the 100-Ti4O7/g-C3N4 composite (fabricated at 100°C) and pure g-C3N4. The enhanced photocatalytic performance of 160-Ti4O7/g-C3N4 could be ascribed to the effective charge separation and enhanced photoabsorption efficiency. Additionally, electron spin resonance (ESR) results showed that hydroxyl radicals and superoxide anion radicals were mainly responsible to the oxidation of hypophosphite with superoxide anion radicals accounting for a more significant contribution. Moreover, Ti4O7/g-C3N4 photocatalysts showed the remarkable stability in the repetitive experiments. PMID:29546041

Ti4O7/g-C3N4 Visible Light Photocatalytic Performance on Hypophosphite Oxidation: Effect of Annealing Temperature.

PubMed

Guan, Wei; Sun, Gaoge; Yin, Lei; Zhang, Zhenghua; Tian, Shichao

2018-01-01

The oxidation of hypophosphite to phosphate is the key to recover the phosphorus resource from the hypophosphite wastewater. In the present work, Ti 4 O 7 /g-C 3 N 4 composites were synthesized at two different temperatures (100 and 160°C) and their performance on photocatalytic oxidation of hypophosphite under visible light irradiation and the corresponding mechanism were evaluated. A hydrolysis method using g-C 3 N 4 and Ti 4 O 7 was applied to synthesize the Ti 4 O 7 /g-C 3 N 4 composites with their hybrid structure and morphology confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS). The annealing temperature significantly affected the photocatalytic performance of Ti 4 O 7 /g-C 3 N 4 that the 160-Ti 4 O 7 /g-C 3 N 4 composite (fabricated at 160°C) showed the highest oxidation efficiency of hypophosphite of 81% and the highest photocatalytic oxidation rate of 0.467 h -1 comparing with the 100-Ti 4 O 7 /g-C 3 N 4 composite (fabricated at 100°C) and pure g-C 3 N 4 . The enhanced photocatalytic performance of 160-Ti 4 O 7 /g-C 3 N 4 could be ascribed to the effective charge separation and enhanced photoabsorption efficiency. Additionally, electron spin resonance (ESR) results showed that hydroxyl radicals and superoxide anion radicals were mainly responsible to the oxidation of hypophosphite with superoxide anion radicals accounting for a more significant contribution. Moreover, Ti 4 O 7 /g-C 3 N 4 photocatalysts showed the remarkable stability in the repetitive experiments.

Anti-tumorigenic action of 2-[piperidinoethoxyphenyl]-3-[4-hydroxyphenyl]-2H-benzo(b)pyran: evidence for involvement of GPR30/EGFR signaling pathway.

PubMed

Chandra, V; Fatima, I; Saxena, R; Hussain, M K; Hajela, K; Sankhwar, P; Roy, B G; Chandna, S; Dwivedi, A

2013-05-01

The aim of the present study was to investigate the effect of non-steroidal, pure antiestrogenic benzopyran derivative i.e., 2-[piperidinoethoxyphenyl]-3-[4-hydroxyphenyl]-2H-benzo(b)pyran (K-1) on the growth of human endometrial cancer cells in vivo and in vitro and to elucidate its mechanism of action. Cell proliferation was assayed by measuring the incorporation of 5'-bromo-2'-deoxyuridine in Ishikawa and primary endometrial cancer cells. The expression of proliferation and apoptotic markers was analyzed by immunoblotting. The effect of K-1 on GPR30-regulated proteins was analyzed by ELISA and by immunoblotting. Nude mice bearing subcutaneous implanted-Ishikawa tumors, were treated for 14days with K-1 (200μg/kg body weight/day/orally). The proliferation markers, GPR30-regulated proteins and apoptotic markers were analyzed by immunoblotting in tumor xenograft. The apoptotic effect of compound K-1 was determined by TUNEL assay. Compound K-1 inhibited proliferation of endometrial adenocarcinoma cells and decreased the expression of proliferation markers. It caused apoptosis by increasing the expression of apoptotic markers (NOXA, PUMAα) and reducing the expression of p-CREB and BclxL. Compound interfered with GPR30-regulated-EGFR activation, decreased p-ERK, p-c-jun, c-fos, cyclinD1 and c-myc expression. Treatment of tumor-bearing mice with K-1 resulted in a significant decrease in tumor volume and weight. Decreased expression of p-ERK and its downstream molecules and increased expression of apoptotic markers were observed in tumor in K-1 treated animals. Findings suggest the potent inhibitory effect of compound K-1 on endometrial cancer cellular growth (in-vitro) and on tumor size (in-vivo) which is mediated at least, in part, by interference with GPR30-signaling. Copyright © 2013 Elsevier Inc. All rights reserved.

NMR analysis of the iron ligand ethylenediaminedi(o-hydroxyphenyl)acetic acid (EDDHA) employed in fertilizers.

PubMed

Cremonini, M A; Alvarez-Fernández, A; Lucena, J J; Rombolà, A; Marangoni, B; Placucci, G

2001-08-01

The exceptional efficiency of the iron chelate of ethylenediaminedi(o-hydroxyphenyl)acetic acid (o,o-EDDHA) in correcting iron chlorosis in plants and the medical applications of various metallic chelates of this compound have long been recognized. As commercial preparations of o,o-EDDHA usually contain impurities, a method for their detection is proposed. By using one- and two-dimensional nuclear magnetic resonance two impurities were identified. The structure of one of these compounds was assigned to an isomer of EDDHA containing at least one p-hydroxyphenyl moiety. The structure of the other impurity was tentatively assigned to a byproduct of the EDDHA synthesis: 2,6-di[CH(COOH)NHCH(2)CH(2)NHCH(COOH)Ar]phenol (Ar = hydroxyphenyl). Both compounds were also detected in the EDDHA extracted from a commercial iron fertilizer.

The Nedd4-binding partner 1 (N4BP1) protein is an inhibitor of the E3 ligase Itch

PubMed Central

Oberst, Andrew; Malatesta, Martina; Aqeilan, Rami I.; Rossi, Mario; Salomoni, Paolo; Murillas, Rodolfo; Sharma, Prashant; Kuehn, Michael R.; Oren, Moshe; Croce, Carlo M.; Bernassola, Francesca; Melino, Gerry

2007-01-01

Nedd4-binding partner-1 (N4BP1) has been identified as a protein interactor and a substrate of the homologous to E6AP C terminus (HECT) domain-containing E3 ubiquitin–protein ligase (E3), Nedd4. Here, we describe a previously unrecognized functional interaction between N4BP1 and Itch, a Nedd4 structurally related E3, which contains four WW domains, conferring substrate-binding activity. We show that N4BP1 association with the second WW domain (WW2) of Itch interferes with E3 binding to its substrates. In particular, we found that N4BP1 and p73α, a target of Itch-mediated ubiquitin/proteasome proteolysis, share the same binding site. By competing with p73α for binding to the WW2 domain, N4BP1 reduces the ability of Itch to recruit and ubiquitylate p73α and inhibits Itch autoubiquitylation activity both in in vitro and in vivo ubiquitylation assays. Similarly, both c-Jun and p63 polyubiquitylation by Itch are inhibited by N4BP1. As a consequence, genetic and RNAi knockdown of N4BP1 diminish the steady-state protein levels and significantly impair the transcriptional activity of Itch substrates. Notably, stress-induced induction of c-Jun was impaired in N4BP1−/− cells. These results demonstrate that N4BP1 functions as a negative regulator of Itch. In addition, because inhibition of Itch by N4BP1 results in the stabilization of crucial cell death regulators such as p73α and c-Jun, it is conceivable that N4BP1 may have a role in regulating tumor progression and the response of cancer cells to chemotherapy. PMID:17592138

The Nedd4-binding partner 1 (N4BP1) protein is an inhibitor of the E3 ligase Itch.

PubMed

Oberst, Andrew; Malatesta, Martina; Aqeilan, Rami I; Rossi, Mario; Salomoni, Paolo; Murillas, Rodolfo; Sharma, Prashant; Kuehn, Michael R; Oren, Moshe; Croce, Carlo M; Bernassola, Francesca; Melino, Gerry

2007-07-03

Nedd4-binding partner-1 (N4BP1) has been identified as a protein interactor and a substrate of the homologous to E6AP C terminus (HECT) domain-containing E3 ubiquitin-protein ligase (E3), Nedd4. Here, we describe a previously unrecognized functional interaction between N4BP1 and Itch, a Nedd4 structurally related E3, which contains four WW domains, conferring substrate-binding activity. We show that N4BP1 association with the second WW domain (WW2) of Itch interferes with E3 binding to its substrates. In particular, we found that N4BP1 and p73 alpha, a target of Itch-mediated ubiquitin/proteasome proteolysis, share the same binding site. By competing with p73 alpha for binding to the WW2 domain, N4BP1 reduces the ability of Itch to recruit and ubiquitylate p73 alpha and inhibits Itch autoubiquitylation activity both in in vitro and in vivo ubiquitylation assays. Similarly, both c-Jun and p63 polyubiquitylation by Itch are inhibited by N4BP1. As a consequence, genetic and RNAi knockdown of N4BP1 diminish the steady-state protein levels and significantly impair the transcriptional activity of Itch substrates. Notably, stress-induced induction of c-Jun was impaired in N4BP1(-/-) cells. These results demonstrate that N4BP1 functions as a negative regulator of Itch. In addition, because inhibition of Itch by N4BP1 results in the stabilization of crucial cell death regulators such as p73 alpha and c-Jun, it is conceivable that N4BP1 may have a role in regulating tumor progression and the response of cancer cells to chemotherapy.

Potential for 4-n-nonylphenol biodegradation in stream sediments

USGS Publications Warehouse

Bradley, P.M.; Barber, L.B.; Kolpin, D.W.; McMahon, P.B.; Chapelle, F.H.

2008-01-01

The potential for in situ biodegradation of 4-nonylphenol (4-NP) was investigated in three hydrologically distinct streams impacted by wastewater treatment plants (WWTPs) in the United States. Microcosms were prepared with sediments from each site and amended with [U-ring-14C]4-n-nonylphenol (4-n-NP) as a model test substrate. Microcosms prepared with sediment collected upstream of the WWTP outfalls and incubated under oxic conditions showed rapid and complete mineralization of [U-ring-14C]4- n-NP to 14CO2 in all three systems. In contrast, no mineralization of [U-ring-14C]4-n-NP was observed in these sediments under anoxic (methanogenic) conditions. The initial linear rate of [U-ring-14C]4-n-NP mineralization in sediments from upstream and downstream of the respective WWTP outfalls was inversely correlated with the biochemical oxygen demand (BOD) of the streambed sediments. These results suggest that the net supply of dissolved oxygen to streambed sediments is a key determinant of the rate and extent of 4-NP biodegradation in stream systems. In the stream systems considered by the present study, dissolved oxygen concentrations in the overlying water column (8–10 mg/L) and in the bed sediment pore water (1–3 mg/L at a depth of 10 cm below the sediment–water interface) were consistent with active in situ 4-NP biodegradation. These results suggest WWTP procedures that maximize the delivery of dissolved oxygen while minimizing the release of BOD to stream receptors favor efficient biodegradation of 4-NP contaminants in wastewater-impacted stream environments.

Fate of ( sup 14 C)monolinuron in potatoes and soil under outdoor conditions

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

Freitag, D.; Scheunert, I.

1990-12-01

(phenyl-{sup 14}C)Monolinuron was applied (2.5 and 1.9 kg/ha) to the soil surface of an outdoor lysimeter in two successive years: then, potatoes were grown. Total recovery of {sup 14}C in soil, plants, and leached water was about 55% (of {sup 14}C applied) after the first growing period and about 43% after the second growing period. Radioactivity in soil contained 77.1% (based on total {sup 14}C recovered in soil) bound residues, 15% monolinuron, and the following conversion products: N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea, N-(4-chlorophenyl)-N'-methylurea. N-(4-chlorophenyl)methylcarbamate, N-(4-chlorophenyl)-N-methyl-methylcarbamate, and 4-chloroformanilide. The leachate contained 0.8% (based on total {sup 14}C recovered in leachate) N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea. Potato plants contained 0.106more » mg/kg radioactive residues in peeled tubers after one growing period and 15.94 mg/kg in the tops; after two growing periods, peeled tubers contained 0.091 mg/kg and tops contained 18.87 mg/kg radioactive residues. These residues consisted of bound {sup 14}C (57.9% of total {sup 14}C recovered in plants), N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea, N-(4-chlorophenyl)-N'-methylurea, N-(4-chlorophenyl)methylcarbamate, N-(4-chlorophenyl)-N-methyl-methylcarbamate, and 4,4'-dichlorozobenzene.« less

Molecular design of new nitramine explosives: 1,3,5,7-tetranitro-8-(nitromethyl)-4-imidazolino[4,5-b]4-imidazolino-[4,5-e] pyridine and its N-oxide.

PubMed

Liu, Hui; Du, Hongchen; Wang, Guixiang; Liu, Yan; Gong, Xuedong

2012-04-01

Two new nitramine compounds containing pyridine, 1,3,5,7-tetranitro-8-(nitromethyl) -4-imidazolino[4,5-b]4-imidazolino-[4,5-e]pyridine and its N-oxide 1,3,5,7-tetranitro-8- (nitromethyl)-4-imidazolino[4,5-b]4-imidazolino-[4,5-e]pyridine-4-ol were proposed. Density functional theory (DFT) has been employed to study the molecular geometries, electronic structures, infrared spectra, and thermodynamic properties at the B3LYP/6-31G* level. Their detonation performances evaluated using the Kamlet-Jacobs equations with the calculated densities and heats of formation are superior to those of HMX. The predicted densities of them were ca. 2 g cm(-3), detonation velocities were over 9 km s(-1), and detonation pressures were about 40 GPa, showing that they may be potential candidates of high energy density materials (HEDMs). The natural bond orbital analysis indicated that N-NO(2) bond is the trigger bond during thermolysis process. The stability of the title compounds is slightly lower than that of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12- hexaazaisowurtzitane (CL-20). The results of this study may provide basic information for the molecular design of new HEDMs.

Applications of Subleading-Color Amplitudes in N = 4 SYM Theory

DOE PAGES

Naculich, Stephen G.; Nastase, Horatiu; Schnitzer, Howard J.

2011-01-01

A numore » mber of features and applications of subleading-color amplitudes of N = 4 SYM theory are reviewed. Particular attention is given to the IR divergences of the subleading-color amplitudes, the relationships of N = 4 SYM theory to N = 8 supergravity, and to geometric interpretations of one-loop subleading-color and N k MHV amplitudes of N = 4 SYM theory.« less

Synthesis of N4-(Substituted phenyl)-N4-alkyl/desalkyl-9H-pyrimido[4,5-b]indole-2,4-diamines and Identification of New Microtubule Disrupting Compounds that are Effective against Multidrug Resistant Cells1

PubMed Central

Gangjee, Aleem; Zaware, Nilesh; Devambatla, Ravi Kumar Vyas; Raghavan, Sudhir; Westbrook, Cara D.; Dybdal-Hargreaves, Nicholas F.; Hamel, Ernest; Mooberry, Susan L.

2013-01-01

A series of fourteen N4-(substituted phenyl)-N4-methyl/desmethyl-9H-pyrimido[4,5-b]indole-2,4-diamines was synthesized as potential microtubule targeting agents. The synthesis involved a Fisher indole cyclization of 2-amino-6-hydrazinylpyrimidin-4(3H)-one with cyclohexanone, followed by oxidation, chlorination and displacement with appropriate anilines. Compounds 6, 14 and 15 had low nanomolar potency against MDA-MB-435 tumor cells and depolymerized microtubules. Compound 6 additionally had nanomolar GI50 values against 57 of the NCI 60-tumor panel cell lines. Mechanistic studies showed that 6 inhibited tubulin polymerization and [3H]colchicine binding to tubulin. The most potent compounds were all effective in cells expressing P-glycoprotein or the βIII isotype of tubulin, which have been associated with clinical drug reisistence. Modeling studies provided the potential interactions of 6, 14 and 15 within the colchicine site. PMID:23332369

Rare Earth 4f Hybridization with the GaN Valence Band

DTIC Science & Technology

2012-01-01

DOS of Ga17GdN18. and Auger-like electrons emitted in a super Coster– Kronig process [52] 4d104fN + hν → [4d94fN+1]∗ → 4d104fN−1 + e−, (2) where...similar, albeit not identical, response for GaN:Er compared to GaN:Gd at the photon energy characteristic for the Er 4d → 4f super Coster– Kronig resonance

Highly Corrosion Resistant and Sandwich-like Si3N4/Cr-CrNx/Si3N4 Coatings Used for Solar Selective Absorbing Applications.

PubMed

Zhang, Ke; Du, Miao; Haoa, Lei; Meng, Jianping; Wang, Jining; Mi, Jing; Liu, Xiaopeng

2016-12-14

Highly corrosion resistant, layer-by-layer nanostructured Si 3 N 4 /Cr-CrN x /Si 3 N 4 coatings were deposited on aluminum substrate by DC/RF magnetron sputtering. Corrosion resistance experiments were performed in 0.5, 1.0, 3.0, and 5.0 wt % NaCl salt spray at 35 °C for 168 h. Properties of the coatings were comprehensively investigated in terms of optical property, surface morphology, microstructure, elemental valence state, element distribution, and potentiodynamic polarization. UV-vis-near-IR spectrophotometer and FTIR measurements show that the change process in optical properties of Si 3 N 4 /Cr-CrN x /Si 3 N 4 /Al coatings can be divided into three stages: a rapid active degradation stage, a steady passivation stage, and a transpassivation degradation stage. With the increase in the concentration of NaCl salt spray, solar absorptance and thermal emittance experienced a slight degradation. SEM images reveal that there is an increase in surface defects, such as microcracks and holes and -cracks. XRD and TEM measurements indicate that the phase structure changed partially and the content of CrO x and Al 2 O 3 has increased. Auger electron spectroscopy shows that the elements of Cr, N, and O have undergone a minor diffusion. Electrochemical polarization curves show that the as-deposited Si 3 N 4 /Cr-CrN x /Si 3 N 4 /Al coatings have excellent corrosion resistance of 3633.858 kΩ, while after corroding in 5.0 wt % NaCl salt spray for 168 h the corrosion resistance dropped to 13.759 kΩ. However, these coatings still have an outstanding performance of high solar absorptance of 0.924 and low thermal emittance of 0.090 after corroding in 3.0 wt % NaCl salt spray for 120 h. Thus, the Si 3 N 4 /Cr-CrN x /Si 3 N 4 /Al coating is a good choice for solar absorber coatings applied in the high-saline environment.

Synthesis of two-dimensional titanium nitride Ti4N3 (MXene)

NASA Astrophysics Data System (ADS)

Urbankowski, Patrick; Anasori, Babak; Makaryan, Taron; Er, Dequan; Kota, Sankalp; Walsh, Patrick L.; Zhao, Mengqiang; Shenoy, Vivek B.; Barsoum, Michel W.; Gogotsi, Yury

2016-06-01

We report on the synthesis of the first two-dimensional transition metal nitride, Ti4N3-based MXene. In contrast to the previously reported MXene synthesis methods - in which selective etching of a MAX phase precursor occurred in aqueous acidic solutions - here a molten fluoride salt is used to etch Al from a Ti4AlN3 powder precursor at 550 °C under an argon atmosphere. We further delaminated the resulting MXene to produce few-layered nanosheets and monolayers of Ti4N3Tx, where T is a surface termination (F, O, or OH). Density functional theory calculations of bare, non-terminated Ti4N3 and terminated Ti4N3Tx were performed to determine the most energetically stable form of this MXene. Bare and functionalized Ti4N3 are predicted to be metallic. Bare Ti4N3 is expected to show magnetism, which is significantly reduced in the presence of functional groups.We report on the synthesis of the first two-dimensional transition metal nitride, Ti4N3-based MXene. In contrast to the previously reported MXene synthesis methods - in which selective etching of a MAX phase precursor occurred in aqueous acidic solutions - here a molten fluoride salt is used to etch Al from a Ti4AlN3 powder precursor at 550 °C under an argon atmosphere. We further delaminated the resulting MXene to produce few-layered nanosheets and monolayers of Ti4N3Tx, where T is a surface termination (F, O, or OH). Density functional theory calculations of bare, non-terminated Ti4N3 and terminated Ti4N3Tx were performed to determine the most energetically stable form of this MXene. Bare and functionalized Ti4N3 are predicted to be metallic. Bare Ti4N3 is expected to show magnetism, which is significantly reduced in the presence of functional groups. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02253g

(2,2) and (0,4) supersymmetric boundary conditions in 3d N =4 theories and type IIB branes

NASA Astrophysics Data System (ADS)

Chung, Hee-Joong; Okazaki, Tadashi

2017-10-01

The half-BPS boundary conditions preserving N =(2 ,2 ) and N =(0 ,4 ) supersymmetry in 3d N =4 supersymmetric gauge theories are examined. The BPS equations admit decomposition of the bulk supermultiplets into specific boundary supermultiplets of preserved supersymmetry. Nahm-like equations arise in the vector multiplet BPS boundary condition preserving N =(0 ,4 ) supersymmetry, and Robin-type boundary conditions appear for the hypermultiplet coupled to the vector multiplet when N =(2 ,2 ) supersymmetry is preserved. The half-BPS boundary conditions are realized in the brane configurations of type IIB string theory.

Catalytic Silylation of N2 and Synthesis of NH3 and N2H4 by Net Hydrogen Atom Transfer Reactions Using a Chromium P4 Macrocycle.

PubMed

Kendall, Alexander J; Johnson, Samantha I; Bullock, R Morris; Mock, Michael T

2018-02-21

We report the first discrete molecular Cr-based catalysts for the reduction of N 2 . This study is focused on the reactivity of the Cr-N 2 complex, trans-[Cr(N 2 ) 2 (P Ph 4 N Bn 4 )] (P 4 Cr(N 2 ) 2 ), bearing a 16-membered tetraphosphine macrocycle. The architecture of the [16]-P Ph 4 N Bn 4 ligand is critical to preserve the structural integrity of the catalyst. P 4 Cr(N 2 ) 2 was found to mediate the reduction of N 2 at room temperature and 1 atm pressure by three complementary reaction pathways: (1) Cr-catalyzed reduction of N 2 to N(SiMe 3 ) 3 by Na and Me 3 SiCl, affording up to 34 equiv N(SiMe 3 ) 3 ; (2) stoichiometric reduction of N 2 by protons and electrons (for example, the reaction of cobaltocene and collidinium triflate at room temperature afforded 1.9 equiv of NH 3 , or at -78 °C afforded a mixture of NH 3 and N 2 H 4 ); and (3) the first example of NH 3 formation from the reaction of a terminally bound N 2 ligand with a traditional H atom source, TEMPOH (2,2,6,6-tetramethylpiperidine-1-ol). We found that trans-[Cr( 15 N 2 ) 2 (P Ph 4 N Bn 4 )] reacts with excess TEMPOH to afford 1.4 equiv of 15 NH 3 . Isotopic labeling studies using TEMPOD afforded ND 3 as the product of N 2 reduction, confirming that the H atoms are provided by TEMPOH.

Construction of all N=4 conformal supergravities.

PubMed

Butter, Daniel; Ciceri, Franz; de Wit, Bernard; Sahoo, Bindusar

2017-02-24

All N=4 conformal supergravities in four space-time dimensions are constructed. These are the only N=4 supergravity theories whose actions are invariant under off-shell supersymmetry. They are encoded in terms of a holomorphic function that is homogeneous of zeroth degree in scalar fields that parametrize an SU(1,1)/U(1) coset space. When this function equals a constant the Lagrangian is invariant under continuous SU(1,1) transformations. The construction of these higher-derivative invariants also opens the door to various applications for nonconformal theories.

4-N, 4-S & 4-O Chloroquine Analogues: Influence of Side Chain Length and Quinolyl Nitrogen pKa on Activity vs. Chloroquine Resistant Malaria+, #

PubMed Central

Natarajan, Jayakumar K.; Alumasa, John; Yearick, Kimberly; Ekoue-Kovi, Kekeli A.; Casabianca, Leah B.; de Dios, Angel C.; Wolf, Christian; Roepe, Paul D.

2009-01-01

Using predictions from heme – quinoline antimalarial complex structures, previous modifications of chloroquine (CQ), and hypotheses for chloroquine resistance (CQR), we synthesize and assay CQ analogues that test structure – function principles. We vary side chain length for both monoethyl and diethyl 4N CQ derivatives. We alter the pKa of the quinolyl N by introducing alkylthio or alkoxy substituents into the 4 position, and vary side chain length for these analogues. We introduce an additional titratable amino group to the side chain of 4O analogues with promising CQR strain selectivity and increase activity while retaining selectivity. We solve atomic resolution structures for complexes formed between representative 4N, 4S and 4O derivatives vs. μ-oxo dimeric heme, measure binding constants for monomeric vs. dimeric heme, and quantify hemozoin (Hz) formation inhibition in vitro. The data provide additional insight for the design of CQ analogues with improved activity vs. CQR malaria. PMID:18512900

Mechanism of the mutagenic action of hydroxylamine. IX. The UV-induced cleavage of the N-O bond in N4-hydroxy-and N4-methoxycytidine and N6-methoxyadenosine.

PubMed Central

Simukova, N A; Yakovlev, D Y; Budowsky, E I

1975-01-01

The principal UV-induced (lambda = 2546nm) reaction of N4-hydroxy- and N4methoxycytidines and N6-methoxyadenosine in neutral aqueous solutions is cleavage of the exocyclic N-O bond with the respective formation of cytidine and adenosine. Quantum yields are 2.8x10(-3) and 2.2x10(-3) M/E for the first two compounds and 9.1x10(-3) M/E for N6-methoxyadenosine. PMID:1052542

AF4 and AF4N protein complexes: recruitment of P-TEFb kinase, their interactome and potential functions

PubMed Central

Scholz, Bastian; Kowarz, Eric; Rössler, Tanja; Ahmad, Khalil; Steinhilber, Dieter; Marschalek, Rolf

2015-01-01

AF4/AFF1 and AF5/AFF4 are the molecular backbone to assemble “super-elongation complexes” (SECs) that have two main functions: (1) control of transcriptional elongation by recruiting the positive transcription elongation factor b (P-TEFb = CyclinT1/CDK9) that is usually stored in inhibitory 7SK RNPs; (2) binding of different histone methyltransferases, like DOT1L, NSD1 and CARM1. This way, transcribed genes obtain specific histone signatures (e.g. H3K79me2/3, H3K36me2) to generate a transcriptional memory system. Here we addressed several questions: how is P-TEFb recruited into SEC, how is the AF4 interactome composed, and what is the function of the naturally occuring AF4N protein variant which exhibits only the first 360 amino acids of the AF4 full-length protein. Noteworthy, shorter protein variants are a specific feature of all AFF protein family members. Here, we demonstrate that full-length AF4 and AF4N are both catalyzing the transition of P-TEFb from 7SK RNP to their N-terminal domain. We have also mapped the protein-protein interaction network within both complexes. In addition, we have first evidence that the AF4N protein also recruits TFIIH and the tumor suppressor MEN1. This indicate that AF4N may have additional functions in transcriptional initiation and in MEN1-dependend transcriptional processes. PMID:26171280

Catalytic Silylation of N 2 and Synthesis of NH 3 and N 2H 4 by Net Hydrogen Atom Transfer Reactions Using a Chromium P 4 Macrocycle

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

Kendall, Alexander J.; Johnson, Samantha I.; Bullock, R. Morris

We report the first discrete molecular Cr-based catalysts for the reduction of N2. This study is focused on the reactivity of the Cr-N2 complex, trans-[Cr(N2)2(PPh4NBn4)] P4Cr(N2)2, bearing a 16-membered tetraphosphine macrocycle. The architecture of the [16]-PPh4NBn4 ligand is critical to preserve the structural integrity of the catalyst. P4Cr(N2)2 was found to mediate the reduction of N2 by three complementary reaction pathways: (1) Cr-catalyzed reduction of N2 to N(SiMe3)3 by Na and Me3SiCl affording up to 34 equiv N(SiMe3)3; (2) stoichiometric reduction of N2 by protons and electrons. For example, the reaction of cobaltocene (CoCp2) and collidinium triflate (ColH[OTf]) at roommore » temperature to afforded 1.9 equiv of NH3, or at -78 °C to afforded a mixture of NH3 and N2H4; (3) the first example of NH3 formation from the reaction of a terminally bound N2 ligand with a traditional H atom source, TEMPOH, (2,2,6,6-tetramethylpiperidine-1-ol). We found that trans-[Cr(15N2)2(PPh4NBn4)] reacts with excess TEMPOH to afford a 1.4 equiv of 15NH3.« less

Non-Abelian Berry phase, instantons, and N=(0,4) supersymmetry

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

Laia, Joao N.

2010-12-15

In supersymmetric quantum mechanics, the non-Abelian Berry phase is known to obey certain differential equations. Here we study N=(0,4) systems and show that the non-Abelian Berry connection over R{sup 4n} satisfies a generalization of the self-dual Yang-Mills equations. Upon dimensional reduction, these become the tt* equations. We further study the Berry connection in N=(4,4) theories and show that the curvature is covariantly constant.

Multielectron spectroscopy: energy levels of K n+ and Rb n+ ions (n = 2, 3, 4)

NASA Astrophysics Data System (ADS)

Khalal, M. A.; Soronen, J.; Jänkälä, K.; Huttula, S.-M.; Huttula, M.; Bizau, J.-M.; Cubaynes, D.; Guilbaud, S.; Ito, K.; Andric, L.; Feng, J.; Lablanquie, P.; Palaudoux, J.; Penent, F.

2017-11-01

A magnetic bottle time-of-flight spectrometer has been used to perform spectroscopy of K n+ and Rb n+ states with ionization degrees n of 2, 3 and 4. Energy levels are directly measured by detecting in coincidence the n electrons that are emitted as a result of single photon absorption. Experimental results are compared with the energies from the NIST atomic database and ab initio multiconfiguration Dirac-Fock calculations. Previously unidentified 3p 4(3P)3d 1 4D energy levels of K2+ are assigned.

Transient-Absorption Spectroscopy of Cis-Trans Isomerization of N,N-dimethyl-4,4'-Azodianiline with 3D-Printed Temperature-Controlled Sample Holder

ERIC Educational Resources Information Center

Kosenkov, Dmytro; Shaw, James; Zuczek, Jennifer; Kholod, Yana

2016-01-01

The laboratory unit demonstrates a project based approach to teaching physical chemistry laboratory where upper-division undergraduates carry out a transient-absorption experiment investigating the kinetics of cis-trans isomerization of N,N-dimethyl-4,4'-azodianiline. Students participate in modification of a standard flash-photolysis spectrometer…

New application of Z-scheme Ag3PO4/g-C3N4 composite in converting CO2 to fuel.

PubMed

He, Yiming; Zhang, Lihong; Teng, Botao; Fan, Maohong

2015-01-06

This research was designed for the first time to investigate the activities of photocatalytic composite, Ag3PO4/g-C3N4, in converting CO2 to fuels under simulated sunlight irradiation. The composite was synthesized using a simple in situ deposition method and characterized by various techniques including Brunauer-Emmett-Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and an electrochemical method. Thorough investigation indicated that the composite consisted of Ag3PO4, Ag, and g-C3N4. The introduction of Ag3PO4 on g-C3N4 promoted its light absorption performance. However, more significant was the formation of heterojunction structure between Ag3PO4 and g-C3N4, which efficiently promoted the separation of electron-hole pairs by a Z-scheme mechanism and ultimately enhanced the photocatalytic CO2 reduction performance of the Ag3PO4/g-C3N4. The optimal Ag3PO4/g-C3N4 photocatalyst showed a CO2 conversion rate of 57.5 μmol · h(-1) · gcat(-1), which was 6.1 and 10.4 times higher than those of g-C3N4 and P25, respectively, under simulated sunlight irradiation. The work found a new application of the photocatalyst, Ag3PO4/g-C3N4, in simultaneous environmental protection and energy production.

Photochromism of 7-(N,N-diethylamino)-4'-hydroxyflavylium in a water-ionic liquid biphasic system.

PubMed

Pina, Fernando; Parola, A Jorge; Melo, Maria João; Laia, César A T; Afonso, Carlos A M

2007-04-28

Photochromism of trans-4-(N,N-diethylamino)-2,4'-dihydroxychalcone, with formation of the photoproduct 7-(N,N-diethylamino)-4'-hydroxyflavylium, is promoted in the ionic liquid phase of a water/[bmim][PF6] biphasic system.

Azido and tetrazolo 1,2,4,5-tetrazine N-oxides

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

Chavez, David E.; Parrish, Damon A.; Mitchell, Lauren

2017-02-23

This paper presents the synthesis and characterization of the oxidation products of 3,6-diazido-1,2,4,5-tetrazine (1) and 6-amino-[1,5-b]tetrazolo-1,2,4,5-tetrazine (2). 3,6-Diazido-1,2,4,5-tetrazine-1,4-dioxide was produced from oxidation with peroxytrifluoroacetic acid, and more effectively using hypofluorous acid, and 2 can be oxidized to two different products, 6-amino-[1,5-b]tetrazolo-1,2,4,5-tetrazine mono-N-oxide and di-N-oxide. These N-oxide compounds display promising performance properties as energetic materials.

Mechanism of inhibition of mammalian tumor and other thymidylate synthases by N sup 4 -hydroxy-dCMP, N sup 4 -hydroxy-5-fluoro-dCMP, and related analogues

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

Rode, W.; Zielinski, Z.; Dzik, J.M.

1990-12-01

N{sup 4}-Hydroxy-dCMP (N{sup 4}-OH-dCMP), N{sup 4}-methoxy-dCMP (N{sup 4}-OMe-dCMP), and their 5-fluoro congeners were all slow-binding inhibitors of Ehrlich carcinoma thymidylate synthase (TS), competitive with respect to dUMP, and had differing kinetic constants describing interactions with the two TS binding sites. N{sup 4}-OH-dCMP was not a substrate and its inactivation of TS was methylenetetrahydrofolate-dependent, hence mechanism-based. K{sub i} values for N{sup 4}-OH-dCMP and its 5-fluoro analogue were in the range 10{sup {minus}7}-10{sup {minus}8} M, 2-3 orders of magnitude higher for the corresponding N{sup 4}-OMe analogues. The 5-methyl analogue of N{sup 4}-OHdCMP was 10{sup 4}-fold less potent, pointing to the anti rotamermore » of the imino form of exocyclic N{sup 4}-OH, relative to the ring N(3), as the active species. This is consistent with weaker slow-binding inhibition of the altered enzyme from 5-FdUrd-resistant, relative to parent, L1210 cells by both FdUMP and N{sup 4}-OH-dCMP, suggesting interaction of both N{sup 4}-OH and C(5)-F groups with the same region of the active center. Kinetic studies with purified enzyme from five sources, viz., Ehrlich carcinoma, L1210 parental, and 5-FdUrd-resistant cells, regenerating rat liver, and the tapeworm Hymenolepis diminuta, demonstrated that addition of a 5-fluoro substituent to N{sup 4}-OH-dCMP increased its affinity from 2- to 20-fold for the enzyme from different sources. With the Ehrlich and tapeworm enzymes, N{sup 4}-OH-FdCMP and FdUMP were almost equally effective inhibitors.« less

Synthesis and biological activity of pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives: in silico approach.

PubMed

Khobragade, Chandrahas N; Bodade, Ragini G; Dawane, Bhaskar S; Konda, Shankaraiah G; Khandare, Namdev T

2010-10-01

Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56 microg, 3g: 2.337 microg, allopurinol: 1.816 microg) and IC(50) (3b: 4.228 microg, 3g: 3.1 microg, allopurinol: 2.9 microg) values. The enzyme-ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (-84.976 kcal/mol) and 3g (-90.921 kcal/mol) compared with allopurinol (-55.01 kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.

Grassmannians for scattering amplitudes in 4d $$\\mathcal{N}=4 $$ SYM and 3d ABJM

DOE PAGES

Elvang, Henriette; Huang, Yu-tin; Keeler, Cynthia; ...

2014-12-31

Scattering amplitudes in 4d N=4 super Yang-Mills theory (SYM) can be described by Grassmannian contour integrals whose form depends on whether the external data is encoded in momentum space, twistor space, or momentum twistor space. Here, after a pedagogical review, we present a new, streamlined proof of the equivalence of the three integral formulations. A similar strategy allows us to derive a new Grassmannian integral for 3d N = 6 ABJM theory amplitudes in momentum twistor space: it is a contour integral in an orthogonal Grassmannian with the novel property that the internal metric depends on the external data. Themore » result can be viewed as a central step towards developing an amplituhedron formulation for ABJM amplitudes. Various properties of Grassmannian integrals are examined, including boundary properties, pole structure, and a homological interpretation of the global residue theorems for N = 4 SYM.« less

Two-dimensional sup 1 H NMR studies on HPr protein from Staphylococcus aureus: Complete sequential assignments and secondary structure

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

Kalbitzer, H.R.; Neidig, K.P.; Hengstenberg, W.

1991-11-19

Complete sequence-specific assignments of the {sup 1}H NMR spectrum of HPr protein from Staphylococcus aureus were obtained by two-dimensional NMR methods. Important secondary structure elements that can be derived from the observed nuclear Overhauser effects are a large antiparallel {beta}-pleated sheet consisting of four strands, A, B, C, D, a segment S{sub AB} consisting of an extended region around the active-center histidine (His-15) and an {alpha}-helix, a half-turn between strands B and C, a segment S{sub CD} which shows no typical secondary structure, and the {alpha}-helical, C-terminal segment S{sub term}. These general structural features are similar to those found earliermore » in HPr proteins from different microorganisms such as Escherichia coli, Bacillus subtilis, and Streptococcus faecalis.« less

Two Novel C3N4 Phases: Structural, Mechanical and Electronic Properties

PubMed Central

Fan, Qingyang; Chai, Changchun; Wei, Qun; Yang, Yintang

2016-01-01

We systematically studied the physical properties of a novel superhard (t-C3N4) and a novel hard (m-C3N4) C3N4 allotrope. Detailed theoretical studies of the structural properties, elastic properties, density of states, and mechanical properties of these two C3N4 phases were carried out using first-principles calculations. The calculated elastic constants and the hardness revealed that t-C3N4 is ultra-incompressible and superhard, with a high bulk modulus of 375 GPa and a high hardness of 80 GPa. m-C3N4 and t-C3N4 both exhibit large anisotropy with respect to Poisson’s ratio, shear modulus, and Young’s modulus. Moreover, m-C3N4 is a quasi-direct-bandgap semiconductor, with a band gap of 4.522 eV, and t-C3N4 is also a quasi-direct-band-gap semiconductor, with a band gap of 4.210 eV, with the HSE06 functional. PMID:28773550

Pd n Ag (4-n) and Pd n Pt (4-n) clusters on MgO (100): a density functional surface genetic algorithm investigation

DOE PAGES

Heard, Christopher J.; Heiles, Sven; Vajda, Stefan; ...

2014-08-07

We employed the novel surface mode of the Birmingham Cluster Genetic Algorithm (S-BCGA) for the global optimisation of noble metal tetramers upon an MgO(100) substrate at the GGA-DFT level of theory. The effect of element identity and alloying in surface-bound neutral subnanometre clusters is determined by energetic comparison between all compositions of Pd nAg (4-n) and Pd nPt (4-n). And while the binding strengths to the surface increase in the order Pt > Pd > Ag, the excess energy profiles suggest a preference for mixed clusters for both cases. The binding of CO is also modelled, showing that the adsorptionmore » site can be predicted solely by electrophilicity. Comparison to CO binding on a single metal atom shows a reversal of the 5s-d activation process for clusters, weakening the cluster surface interaction on CO adsorption. Charge localisation determines homotop, CO binding and surface site preferences. Furthermore, the electronic behaviour, which is intermediate between molecular and metallic particles allows for tunable features in the subnanometre size range.« less

4-N-, 4-S-, and 4-O-chloroquine analogues: influence of side chain length and quinolyl nitrogen pKa on activity vs chloroquine resistant malaria.

PubMed

Natarajan, Jayakumar K; Alumasa, John N; Yearick, Kimberly; Ekoue-Kovi, Kekeli A; Casabianca, Leah B; de Dios, Angel C; Wolf, Christian; Roepe, Paul D

2008-06-26

Using predictions from heme-quinoline antimalarial complex structures, previous modifications of chloroquine (CQ), and hypotheses for chloroquine resistance (CQR), we synthesize and assay CQ analogues that test structure-function principles. We vary side chain length for both monoethyl and diethyl 4-N CQ derivatives. We alter the pKa of the quinolyl N by introducing alkylthio or alkoxy substituents into the 4 position and vary side chain length for these analogues. We introduce an additional titratable amino group to the side chain of 4-O analogues with promising CQR strain selectivity and increase activity while retaining selectivity. We solve atomic resolution structures for complexes formed between representative 4-N, 4-S, and 4-O derivatives vs mu-oxo dimeric heme, measure binding constants for monomeric vs dimeric heme, and quantify hemozoin (Hz) formation inhibition in vitro. The data provide additional insight for the design of CQ analogues with improved activity vs CQR malaria.

Insight into the theoretical and experimental studies of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N(4)-methyl-N(4)- phenylthiosemicarbazone - A potential NLO material

NASA Astrophysics Data System (ADS)

Sangeetha, K. G.; Aravindakshan, K. K.; Safna Hussan, K. P.

2017-12-01

The synthesis, geometrical parameters, spectroscopic studies, optimised molecular structure, vibrational analysis, Mullikan population analysis, MEP, NBO, frontier molecular orbitals and NLO effects of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N-(4)-methyl-N-(4)-phenylthiosemicarbazone, C25H23N5OS (L1) have been communicated in this paper. A combined experimental and theoretical approach was used to explore the structure and properties of the compound. For computational studies, Gaussian 09 program was used. Starting geometry of molecule was taken from X-ray refinement data and has been optimized by using DFT (B3LYP) method with the 6-31+G (d, p) basis sets. NBO analysis gave insight into the strongly delocalized structure, responsible for the nonlinearity and hence the stability of the molecule. Frontier molecular orbitals have been defined to forecast the global reactivity descriptors of L1. The computed first-order hyperpolarizability (β) of the compound is 2 times higher than that of urea and this account for its nonlinear optical property. Simultaneously, a molecular docking study of the compound was performed using GLIDE Program. For this, three biological enzymes, histone deacetylase, ribonucleotide reductase and DNA methyl transferase, were selected as receptor molecules.

(E)-4-Meth-oxy-N'-(2,4,5-tri-meth-oxy-benzyl-idene)benzohydrazide hemihydrate.

PubMed

Chantrapromma, Suchada; Boonnak, Nawong; Horkaew, Jirapa; Quah, Ching Kheng; Fun, Hoong-Kun

2014-02-01

The title compound crystallizes as a hemihydrate, C18H20N2O5·0.5H2O. The mol-ecule exists in an E conformation with respect to the C=N imine bond. The 4-meth-oxy-phenyl unit is disordered over two sets of sites with a refined occupancy ratio of 0.54 (2):0.46 (2). The dihedral angles between the benzene rings are 29.20 (9) and 26.59 (9)°, respectively, for the major and minor components of the 4-meth-oxy-substituted ring. All meth-oxy substituents lie close to the plane of the attached benzene rings [the Cmeth-yl-O-C-C torsion angles range from -4.0 (12) to 3.9 (2)°]. In the crystal, the components are linked into chains propagating along [001] via N-H⋯O and O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions.

Study on Control of NH4 +-N in Surface Water by Photocatalytic

NASA Astrophysics Data System (ADS)

Zuo, Xiaoran; He, Honghua; Yang, Yue; Yan, Chao; Zhou, Ying

2018-01-01

NH4 +-N has become the main pollution factor affecting the surface water quality in China. Based on the theory of photolysis, the feasibility of photolysis removing NH4 +-N in surface water is studied. The effects of pH, CaO2 content and photolysis time on removal rate of NH4 +-N are studied. The actual study is based on Laboratory studies results. Experimental results show: When the pH<7, photolysis can increase the NH4 +-N content. And when pH>8, the photolysis can greatly reduce the NH4 +-N content in water. CaO2 can greatly remove NH4 +-N. The removal rate of NH4 +-N increased with the increase of photocatalytic time. When irradiated with UV light for 108 hours or the sun is irradiated for about 40 days, NH4 +-N content can be reduced from 4mg/L to 0.5mg/L under the optimum experimental conditions. Adjusting the pH of surface water is the most important condition for controlling NH4 +-N content.

Characterization of solvated electrons in hydrogen cyanide clusters: (HCN)n- (n=3, 4)

NASA Astrophysics Data System (ADS)

Wu, Di; Li, Ying; Li, Zhuo; Chen, Wei; Li, Zhi-Ru; Sun, Chia-Chung

2006-02-01

Theoretical studies of the solvated electrons (HCN)n- (n =3, 4) reveal a variety of electron trapping possibilities in the (HCN)n (n =3, 4) clusters. Two isomers for (HCN)3- and four isomers for (HCN)4- are obtained at the MP2/aug -cc-pVDZ+dBF (diffusive bond functions) level of theory. In view of vertical electron detachment energies (VDEs) at the CCSD(T) level, the excess electron always "prefers" locating in the center of the system, i.e., the isomer with higher coordination number shows larger VDE value. However, the most stable isomers of the solvated electron state (HCN)3- and (HCN)4- are found to be the linear C∞ν and D∞h structures, respectively, but not the fullyl symmetric structures which have the largest VDE values.

N4H9Cu7S4: a hydrazinium-based salt with a layered Cu7S4- framework.

PubMed

Mitzi, David B

2007-02-05

Crystals of a hydrazinium-based copper(I) sulfide salt, N4H9Cu7S4 (1), have been isolated by an ambient temperature solution-based process. In contrast to previously reported hydrazinium salts of main-group metal chalcogenides, which consist of isolated metal chalcogenide anions, and ACu7S4 (A = NH4+, Rb+, Tl+, K+), which contains a more three-dimensional Cu7S4- framework with partial Cu-site occupancy, the structure of 1 [P21, a = 6.8621(4) A, b = 7.9851(4) A, c = 10.0983(5) A, beta = 99.360(1) degrees , Z = 2] is composed of extended two-dimensional Cu7S4- slabs with full Cu-site occupancy. The Cu7S4- slabs are separated by a mixture of hydrazinium and hydrazine moieties. Thermal decomposition of 1 into copper(I) sulfide proceeds at a significantly lower temperature than that observed for analogous hydrazinium salts of previously considered metal chalcogenides, completing the transition at temperatures as low as 120 degrees C. Solutions of 1 may be used in the solution deposition of a range of Cu-containing chalcogenide films.

Functional Aromatic Poly(1,3,4-Oxadiazole-Ether)s with Benzimidazole Pendants: Synthesis, Thermal and Dielectric Studies

PubMed Central

Ganesh, Shimoga D.; Pai, Vasantakumar K.; Kariduraganavar, Mahadevappa Y.; Jayanna, Madhu B.

2014-01-01

Poly(1,3,4-oxadiazole-ether) with reactive carboxylic acid pendants was synthesized from solution polymerization via nucleophilic displacement polycondensation among 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole (BFPOx) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). Without altering the polymeric segments, benzimidazole modified poly(1,3,4-oxadiazole-ether)s were prepared by varying stoichiometric ratios of 1,2-phenylenediamine. The molecular structural characterization of these polymers was achieved by, FT-IR, NMR, TGA, elemental analysis, and analytical techniques. The weight-average molecular weight of virgin polymer with carboxylic acid functionality was determined by gel permeation chromatography (GPC) and was found to be 22400 (Mw/Mn = 2.07). All the synthesized polyethers were compressed into pellets and electrical contacts were established to perform dielectric properties. PMID:27437448

Visible Light-Driven Photocatalytic Performance of N-Doped ZnO/g-C3N4 Nanocomposites.

PubMed

Kong, Ji-Zhou; Zhai, Hai-Fa; Zhang, Wei; Wang, Shan-Shan; Zhao, Xi-Rui; Li, Min; Li, Hui; Li, Ai-Dong; Wu, Di

2017-09-06

N-doped ZnO/g-C 3 N 4 composites have been successfully prepared via a facile and cost-effective sol-gel method. The nanocomposites were systematically characterized by XRD, FE-SEM, HRTEM, FT-IR, XPS, and UV-vis DRS. The results indicated that compared with the pure N-doped ZnO, the absorption edge of binary N-doped ZnO/g-C 3 N 4 shifted to a lower energy with increasing the visible-light absorption and improving the charge separation efficiency, which would enhance its photocatalytic activity. Compared with the pure g-C 3 N 4 , ZnO, N-doped ZnO and the composite ZnO/g-C 3 N 4 , the as-prepared N-doped ZnO/g-C 3 N 4 exhibits a greatly enhanced photocatalytic degradation of methylene blue and phenol under visible-light irradiation. Meanwhile, N-doped ZnO/g-C 3 N 4 possesses a high stability. Finally, a proposed mechanism for N-doped ZnO/g-C 3 N 4 is also discussed. The improved photocatalysis can be attributed to the synergistic effect between N-doped ZnO and g-C 3 N 4 , including the energy band structure and enhanced charge separation efficiency.

Integral and differential cross section measurements at low collision energies for the N2++CH4/CD4 reactions

NASA Astrophysics Data System (ADS)

Nicolas, Christophe; Torrents, Raquel; Gerlich, Dieter

2003-02-01

Absolute integral cross sections are measured in the collision energy range between 0.1 to 3.5 eV for the N2++CH4 and N2++CD4 reactions using the universal guided ion beam apparatus. The reaction branching ratio, CX3+:CX2+:N2X+ (X=H or D), is found to be 0.86:0.09:0.05 and 0.88:0.07:0.05 for the N2++CH4 and N2++CD4 reactions, respectively. The CH3+/CH2+ ratio is constant over the whole collision energy range and very similar to the one obtained for the almost isoenergetic Ar++CH4 reaction. Axial velocity distributions of the product ions are measured by time of flight at collision energies between 0.1 and 3.5 eV. The results provide direct insight into the reaction dynamics. The dissociative charge transfer channels, leading to CH3+ and CH2+ product ions, occur via an electron jump combined with some exchange of momentum between the colliding partners. The H (D) transfer leading to N2H+ can be described as a direct process, similar to a spectator stripping mechanism. Various isotope effects are observed, the dominant being that the cross sections for reaction with CH4 are up to 20% bigger than the corresponding ones for CD4.

Hydrazinium lanthanide oxalates: synthesis, structure and thermal reactivity of N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce, Nd.

PubMed

De Almeida, Lucie; Grandjean, Stéphane; Rivenet, Murielle; Patisson, Fabrice; Abraham, Francis

2014-03-28

New hydrazinium lanthanide oxalates N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce (Ce-HyOx) and Nd (Nd-HyOx), were synthesized by hydrothermal reaction at 150 °C between lanthanide nitrate, oxalic acid and hydrazine solutions. The structure of the Nd compound was determined from single-crystal X-ray diffraction data, space group P2₁/c with a = 16.315(4), b = 12.127(3), c = 11.430(2) Å, β = 116.638(4)°, V = 2021.4(7) Å(3), Z = 4, and R1 = 0.0313 for 4231 independent reflections. Two distinct neodymium polyhedra are formed, NdO9 and NdO8N, an oxygen of one monodentate oxalate in the former being replaced by a nitrogen atom of a coordinated hydrazinium ion in the latter. The infrared absorption band at 1005 cm(-1) confirms the coordination of N2H5(+) to the metal. These polyhedra are connected through μ2 and μ3 oxalate ions to form an anionic three-dimensional neodymium-oxalate arrangement. A non-coordinated charge-compensating hydrazinium ion occupies, with water molecules, the resulting tunnels. The N-N stretching frequencies of the infrared spectra demonstrate the existence of the two types of hydrazine ions. Thermal reactivity of these hydrazinium oxalates and of the mixed isotypic Ce/Nd (CeNd-HyOx) oxalate were studied by using thermogravimetric and differential thermal analyses coupled with gas analyzers, and high temperature X-ray diffraction. Under air, fine particles of CeO2 and Ce(0.5)Nd(0.5)O(1.75) are formed at low temperature from Ce-HyOx and CeNd-HyOx, respectively, thanks to a decomposition/oxidation process. Under argon flow, dioxymonocyanamides Ln2O2CN2 are formed.

Ab Initio Calculations of Anharmonic Vibrational Spectroscopy for Hydrogen Fluoride (HF)n (n=3,4) and Mixed Hydrogen Fluoride/Water (HF)n(H20)n (n=1,2,4) Clusters

NASA Technical Reports Server (NTRS)

Chaban, Galina M.; Gerber, R. Benny; Kwak, Dochan (Technical Monitor)

2001-01-01

Anharmonic vibrational frequencies and intensities are computed for hydrogen fluoride clusters (HF)n with n=3,4 and mixed clusters of hydrogen fluoride with water (HF)n(H2O)n where n=1,2. For the (HF)4(H2O)4 complex, the vibrational spectra are calculated at the harmonic level, and anharmonic effects are estimated. Potential energy surfaces for these systems are obtained at the MP2/TZP level of electronic structure theory. Vibrational states are calculated from the potential surface points using the correlation-corrected vibrational self-consistent field (CC-VSCF) method. The method accounts for the anharmonicities and couplings between all vibrational modes and provides fairly accurate anharmonic vibrational spectra that can be directly compared with experimental results without a need for empirical scaling. For (HF)n, good agreement is found with experimental data. This agreement shows that the MP2 potential surfaces for these systems are reasonably reliable. The accuracy is best for the stiff intramolecular modes, which indicates the validity of MP2 in describing coupling between intramolecular and intermolecular degrees of freedom. For (HF)n(H2O)n experimental results are unavailable. The computed intramolecular frequencies show a strong dependence on cluster size. Intensity features are predicted for future experiments.

Modulatory Effect of 2-(4-Hydroxyphenyl)amino-1,4-naphthoquinone on Endothelial Vasodilation in Rat Aorta.

PubMed

Palacios, Javier; Cifuentes, Fredi; Valderrama, Jaime A; Benites, Julio; Ríos, David; González, Constanza; Chiong, Mario; Cartes-Saavedra, Benjamín; Lafourcade, Carlos; Wyneken, Ursula; González, Pamela; Owen, Gareth I; Pardo, Fabián; Sobrevia, Luis; Buc Calderon, Pedro

The vascular endothelium plays an essential role in the control of the blood flow. Pharmacological agents like quinone (menadione) at various doses modulate this process in a variety of ways. In this study, Q7 , a 2-phenylamino-1,4-naphthoquinone derivative, significantly increased oxidative stress and induced vascular dysfunction at concentrations that were not cytotoxic to endothelial or vascular smooth muscle cells. Q7 reduced nitric oxide (NO) levels and endothelial vasodilation to acetylcholine in rat aorta. It also blunted the calcium release from intracellular stores by increasing the phenylephrine-induced vasoconstriction when CaCl 2 was added to a calcium-free medium but did not affect the influx of calcium from extracellular space. Q7 increased the vasoconstriction to BaCl 2 (10 -3  M), an inward rectifying K + channels blocker, and blocked the vasodilation to KCl (10 -2  M) in aortic rings precontracted with BaCl 2 . This was recovered with sodium nitroprusside (10 -8  M), a NO donor. In conclusion, Q7 induced vasoconstriction was through a modulation of cellular mechanisms involving calcium fluxes through K + channels, and oxidative stress induced endothelium damage. These findings contribute to the characterization of new quinone derivatives with low cytotoxicity able to pharmacologically modulate vasodilation.

Synthesis, characterization and computational studies of 3-{(E)-[(2-hydroxyphenyl)imino]methyl}benzene-1,2-diol and molecular structure of its zwitterionic form

NASA Astrophysics Data System (ADS)

Ezeorah, Julius Chigozie; Ossai, Valentine; Obasi, Lawrence Nnamdi; Elzagheid, Mohamed I.; Rhyman, Lydia; Lutter, Michael; Jurkschat, Klaus; Dege, Necmi; Ramasami, Ponnadurai

2018-01-01

The Schiff base 3-{(E)-[(2-hydroxyphenyl)imino]methyl}benzene-1,2-diol was synthesized by the condensation of 2,3-dihydroxybenzaldehyde and 2-aminophenol in water at room temperature. The crystal was grown using two solvents (dry methanol and 60% methanol). The compound was characterized using elemental microanalysis, IR, NMR, UV spectroscopies and single-crystal X-ray diffraction crystallography. The X-ray structure reveals that the Schiff base crystallizes as a methanol solvate in dry methanol with triclinic crystal system, space group P-1 and Z = 2 in the unit cell and as a non-methanol solvate in 60% methanol with triclinic crystal system, space group P-1 and Z = 4 in the unit cell. The compound showed absorption bands at 272, 389, 473 and 602 nm in DMSO. These bands were assigned as π → π ∗, n → π∗ and n-σ∗ transitions. The 473 and 602 nm bands in DMSO reveal that the compound exists in tautomeric forms. The presence of N-H, C-O and Cdbnd N stretching vibrations in the IR spectrum indicates that the compound is zwitterionic in the solid state. This study was supplemented using density functional theory method.

Lignification in transgenics deficient in 4-coumarate 3-hydroxylase (C3H)or the associated hydroxycinnamoyl transferase (HCT)

Treesearch

John Ralph; Takuya Akiyama; Hoon Kim; Fachuang Lu; Sally A. Ralph; Clint Chapple; Ramesh B. Nair; Armin Wagner; Fang Chen; M.S. Srinivasa Reddy; Richard A Dixon; Heather D. Coleman; Shawn D. Mansfield

2006-01-01

Down-regulation of the gene encoding 4-coumarate 3-hydroxylase (C3H) in angiosperms massively but predictably increased the proportion of p-hydroxyphenyl (P) units relative to the normally dominant syringyl (S) and guaiacyl (G) units. Alfalfa stem levels of up to ~65% P (from wild-type (WT) levels of ~1%) resulting from down-regulation of C3H were measured by...

Photo reduction of CO2 to CH4 on g-C3N4: The effect of concentrating light and pretreatment

NASA Astrophysics Data System (ADS)

Li, Dong; Fang, Xiaoxiang; Liu, Huayan; Lu, Hanfeng; Zhang, Zekai

2018-06-01

The behavior of CO2 photoreduction to CH4 on the g-C3N4 catalyst was studied in a concentrating light reactor. The g-C3N4 catalysts before and after pretreatment were characterized by FE-SEM, XRD and photoilluminance. It is found that concentrating light increases the CH4 yield on the g-C3N4 by heightening the incident light intensity, and light pretreatment has an excessive effect on the performance. Pretreated by suitable light intensity, air atmosphere and time, the CH4 yield on the g-C3N4 under concentrating light irradiation reached about 3.39 μmol.g-1.h-1, which is about 16 times of that g-C3N4 reacted at nature incident light without pretreatment. The mechanism of pretreatment is considered to be from the surface oxidation state change of the catalyst either from the oxidation of the catalyst surface or the activation of surface oxygen.

The synthesis and crystal structure of 2-[4(S)-4,5-dihydro-4-phenyl-2-oxazolinyl]-benzenamine, and 2-[4(S)-4,5-dihydro-4-benzyl-2-oxazolinyl]-benzenamine

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

Mei Luo, E-mail: Lmhh5523385@yahoo.cn; Hai Zhangjia; Hao Yin

2010-12-15

Two oxazolines compound 1a and 1b, 2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl-benzenamine, and (C{sub 15}H{sub 14}N{sub 2}O), 2-[4(S)-4,5-dihydro-4-benzyl-2-ozazolinyl-benzenamine (C{sub 16}H{sub 16}N{sub 2}O) were obtained in moderate yield from the reactions of 2-aminobenzonitrile with optically active L-(+)-Phenylglycinol and L-(+)-Phenylalaninol, respectively, in chlorobenzene under dry, anaerobic conditions. ZnCl{sub 2} was dried under vacuum and acted as a Lewis acid catalyst in this reaction. The structures of 1a and 1b were determined by X-ray diffraction and NMR. There exist intra- and intermolecular N-H-N hydrogen bonds in the crystal structure.

N-demethylation of N-methyl-4-aminoantipyrine, the main metabolite of metamizole.

PubMed

Bachmann, Fabio; Duthaler, Urs; Rudin, Deborah; Krähenbühl, Stephan; Haschke, Manuel

2018-05-08

Metamizole is an old analgesic used frequently in some countries. Active metabolites of metamizole are the non-enzymatically generated N-methyl-4-aminoantipyrine (4-MAA) and its demethylation product 4-aminoantipyrine (4-AA). Previous studies suggested that 4-MAA demethylation can be performed by hepatic cytochrome P450 (CYP) 3A4, but the possible contribution of other CYPs remains unclear. Using human liver microsomes (HLM), liver homogenate and HepaRG cells, we could confirm 4-MAA demethylation by CYPs. Based on CYP induction (HepaRG cells) and CYP inhibition (HLM) we could identify CYP2B6, 2C8, 2C9 and 3A4 as major contributors to 4-MAA demethylation. The 4-MAA demethylation rate by HLM was 280 pmol/mg protein/h, too low to account for in vivo 4-MAA demethylation in humans. Since peroxidases can perform N-demethylation, we investigated horseradish peroxidase and human myeloperoxidase (MPO). Horse radish peroxidase efficiently demethylated 4-MAA, depending on the hydrogen peroxide concentration. This was also true for MPO; this reaction was saturable with a K m of 22.5 μM and a maximal velocity of 14 nmol/min/mg protein. Calculation of the entire body MPO capacity revealed that the demethylation capacity by granulocyte/granulocyte precursors was approximately 600 times higher than the liver capacity and could account for 4-MAA demethylation in humans. 4-MAA demethylation could also be demonstrated in MPO-expressing granulocyte precursor cells (HL-60). In conclusion, 4-MAA can be demethylated in the liver by several CYPs, but hepatic metabolism cannot fully explain 4-MAA demethylation in humans. The current study suggests that the major part of 4-MAA is demethylated by circulating granulocytes and granulocyte precursors in bone marrow. Copyright © 2018 Elsevier B.V. All rights reserved.

Crystal structure of 4,4′-(disulfanediyl)dibutanoic acid–4,4′-bipyridine (1/1)

PubMed Central

Atria, Ana María; Garland, Maria Teresa; Baggio, Ricardo

2014-01-01

4,4′-(Disulfanediyl)dibutanoic acid (dtba) and 4,4′-bipyridine (4,4′-bpy) crystallize in an 1:1 ratio, leading to the title co-crystal with composition C8H14O4S2·C10H8N2. A distinctive feature of the crystal structure is the geometry of the dtba moiety, which appears to be stretched [with a 9.98 (1) Å span between outermost carbons] and acts as an hydrogen-bonding connector, forming linear chains along [-211] with the 4,4′-bpy moiety by way of O—H⋯N hydrogen bonds and C—H⋯O interactions. The influence of the mol­ecular shape on the hydrogen-bonding pattern is analysed by comparing the title compound and two other 4,4′-bpy co-crystals with closely related mol­ecules of similar formulation but different geometry, showing the way in which this correlates with the packing arrangement. PMID:25309167

Novel H5N8 clade 2.3.4.4 highly pathogenic avian influenza virus in wild awuatic birds, Russia, 2016

USDA-ARS?s Scientific Manuscript database

H5N1 high pathogenicity avian influenza virus (HPAIV) emerged in 1996 in Guangdong China (Gs/GD) and has evolved into multiple genetic clades. Since 2008, HPAIV H5 clade 2.3.4 with N2, N5 and N8 neuraminidase subtypes have been identified in mainland China and outbreak of HPAIV H5N8 clade 2.3.4.4 ou...

40 CFR 721.10187 - 4-Morpholinepropanamine, N-(1,3-dimethylbutylidene)-.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-morpholinepropanamine, N-(1,3-dimethylbutylidene)- (PMN P-05-186, Chemical A; CAS No. 1003863-30-6) is subject to... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 4-Morpholinepropanamine, N-(1,3... Specific Chemical Substances § 721.10187 4-Morpholinepropanamine, N-(1,3-dimethylbutylidene)-. (a) Chemical...

A Theoretical Study on N'-[(Z)-(4-Methylphenyl)Methylidene]-4-Nitrobenzohydrazide (NMPMN)

NASA Astrophysics Data System (ADS)

Okur, Muhammet; Albayrak, Nazmiye; Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

2018-05-01

Quantum mechanical calculations of ground state energy, vibration wavenumbers, and electronic absorption wavelengths of N'-[(Z)-(4-methylphenyl)methylidene]-4-nitrobenzohydrazide with C15H13N3O3 empirical formula was performed by using Gaussian 09 program. Becke's three-parameter exchange functional in conjunction with the Lee-Yang-Parr correlation functional and Heyd-Scuseria-Ernzerhof functional levels of density functional theory (DFT) with the 6-311++G(d,p) basis set were used in the performing of above mentioned calculations. The highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) energies have been also calculated at the same levels. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) behavior of the title molecule has been examined by the determining of electric dipole moment (μ), polarizability (α), and static first-order hyperpolarizability (β). Finally, molecular electrostatic potential (MEP) surface as well as Mulliken and NBO atomic charges were calculated by using Gaussian 09 program.

Ab initio calculations of anharmonic vibrational spectroscopy for hydrogen fluoride (HF)n (n = 3, 4) and mixed hydrogen fluoride/water (HF)n(H2O)n (n = 1, 2, 4) clusters

NASA Technical Reports Server (NTRS)

Chaban, Galina M.; Gerber, R. Benny

2002-01-01

Anharmonic vibrational frequencies and intensities are computed for hydrogen fluoride clusters (HF)n, with n = 3, 4 and mixed clusters of hydrogen fluoride with water (HF)n(H2O)n where n = 1, 2. For the (HF)4(H2O)4 complex, the vibrational spectra are calculated at the harmonic level, and anharmonic effects are estimated. Potential energy surfaces for these systems are obtained at the MP2/TZP level of electronic structure theory. Vibrational states are calculated from the potential surface points using the correlation-corrected vibrational self-consistent field method. The method accounts for the anharmonicities and couplings between all vibrational modes and provides fairly accurate anharmonic vibrational spectra that can be directly compared with experimental results without a need for empirical scaling. For (HF)n, good agreement is found with experimental data. This agreement shows that the Moller-Plesset (MP2) potential surfaces for these systems are reasonably reliable. The accuracy is best for the stiff intramolecular modes, which indicates the validity of MP2 in describing coupling between intramolecular and intermolecular degrees of freedom. For (HF)n(H2O)n experimental results are unavailable. The computed intramolecular frequencies show a strong dependence on cluster size. Intensity features are predicted for future experiments.

Fluorescence spectroscopy and amplified spontaneous emission (ASE) of phenylimidazoles: predicted vibronic coupling along the excited-state intramolecular proton transfer in 2-(2'-hydroxyphenyl)imidazoles.

PubMed

del Valle, Juan Carlos; Claramunt, R M; Catalán, J

2008-06-26

Methylation at the 1N position of 2-phenylimidazole provides the shortest wavelength for a liquid-state laser dye reported to date; that is, the 1-methyl-2-phenylimidazole molecule in cyclohexane solution yields amplified spontaneous emission (ASE) with a peak wavelength at 314.5 nm and a constant laser gain value of 5 cm(-1) from 310 to 317 nm. Methyl substitution in this case favors the appearance of laser action (owing to a torsion-vibrational mechanism) in cyclohexane as compared with the nonmethylated species which does not exhibit ASE in this solvent. The 2-(2'-hydroxyphenyl)imidazole molecules give rise to ASE with high gain values (ca. 9 cm(-1)) at 450 and 466 nm. The mechanism of population inversion is understood in terms of a vibronic coupling between the hydroxyl stretching motion and the torsional vibration of the phenyl and imidazole rings. The proton-transfer spectroscopy of 2-(2'-hydroxyphenyl)imidazoles is studied in dioxane, cyclohexane, dimethyl sulfoxide, methanol, and water. The greater the acidity of the solvent the greater the disruption of the intramolecular hydrogen bond; solvent acidity is the main parameter which favors formation of the open-form species in the ground electronic state. Methyl substitution at the 1N position favors formation of the open species for 2-hydroxyphenylimidazoles in the ground electronic state, which decreases their own capacity to undergo ASE. Low-temperature absorption spectroscopy confirms aggregation processes for 2-(2'-hydroxyphenyl)imidazoles in solution. In accordance with X-ray analyses in the solid phase, these molecules form associations through intermolecular chains of the type N-H...O or O-H...N.

Response to Comment on "Synthesis and characterization of the pentazolate anion cyclo-N5- in (N5)6(H3O)3(NH4)4Cl".

PubMed

Jiang, Chao; Zhang, Lei; Sun, Chengguo; Zhang, Chong; Yang, Chen; Chen, Jun; Hu, Bingcheng

2018-03-16

Huang and Xu argue that the cyclo -N 5 - ion in (N 5 ) 6 (H 3 O) 3 (NH 4 ) 4 Cl we described in our report is theoretically unfavorable and is instead protonated. Their conclusion is invalid, as they use an improper method to assess the proton transfer in a solid crystal structure. We present an in-depth experimental and theoretical analysis of (N 5 ) 6 (H 3 O) 3 (NH 4 ) 4 Cl that supports the results in the original paper. Copyright © 2018, American Association for the Advancement of Science.

Nanocomposite of exfoliated bentonite/g-C3N4/Ag3PO4 for enhanced visible-light photocatalytic decomposition of Rhodamine B.

PubMed

Ma, Jianfeng; Huang, Daiqin; Zhang, Wenyi; Zou, Jing; Kong, Yong; Zhu, Jianxi; Komarneni, Sridhar

2016-11-01

Novel visible-light-driven heterojunction photocatalyst comprising exfoliated bentonite, g-C3N4 and Ag3PO4 (EB/g-C3N4/Ag3PO4) was synthesized by a facile and green method. The composites EB/g-C3N4/Ag3PO4 were characterized by X-ray diffraction, Transmission electron microscopy, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy and the Brunauer, Emmett, and Teller (BET) surface area method. Under visible light irradiation, EB/g-C3N4/Ag3PO4 composites displayed much higher photocatalytic activity than that of either pure g-C3N4 or pure Ag3PO4 in the degradation of Rhodamine B (RhB). Among the hybrid photocatalysts, EB/g-C3N4/Ag3PO4 composite containing 20 wt% Ag3PO4 exhibited the highest photocatalytic activity for the decolorization of RhB. Under the visible-light irradiation, the RhB dye was completely decolorized in less than 60 min. The enhanced photocatalytic performance is attributed to the stable structure, enlarged surface area, strong adsorbability, strong light absorption ability, and high-efficiency separation rate of photoinduced electron-hole pairs. Our finding paves a way to design highly efficient and stable visible-light-induced photocatalysts for practical applications in wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification and analytical characterization of nine synthetic cathinone derivatives N-ethylhexedrone, 4-Cl-pentedrone, 4-Cl-α-EAPP, propylone, N-ethylnorpentylone, 6-MeO-bk-MDMA, α-PiHP, 4-Cl-α-PHP, and 4-F-α-PHP.

PubMed

Liu, Cuimei; Jia, Wei; Li, Tao; Hua, Zhendong; Qian, Zhenhua

2017-08-01

Clinical and forensic toxicology laboratories are continuously confronted by analytical challenges when dealing with the new psychoactive substances (NPS) phenomenon. In this study, the analytical characterization of nine synthetic cathinones is described: 2-(ethylamino)-1-phenylhexan-1-one (N-ethylhexedrone 1), 1-(4-chlorophenyl)-2-(methylamino)pentan-1-one (4-Cl-pentedrone 2), 1-(4-chlorophenyl)-2-(ethylamino)pentan-1-one (4-Cl-α-EAPP 3), 1-(3,4-methylenedioxyphenyl)-2-propylaminopropan-1-one (propylone 4), 1-(3,4-methylenedioxyphenyl)-2-ethylaminopentan-1-one (N-ethylnorpentylone 5), 1-(6-methoxy-3,4-methylenedioxyphenyl)-2-methylaminopropan-1-one (6-MeO-bk-MDMA 6), 4-methyl-1-phenyl-2-(pyrrolidin-1-yl)pentan-1-one (α-PiHP 7), 1-(4-chlorophenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-Cl-α-PHP 8), and 1-(4-fluorophenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-F-α-PHP 9). The identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The mass-spectral fragmentations of these compounds following collision-induced dissociation (CID) and electron ionization (EI) were studied to assist forensic laboratories in identifying these compounds or other substances with similar structure in their case work. To our knowledge, no analytical data about the compounds 1-4, 7, and 8 have appeared until now, making this the first report on these compounds. The GC-MS data of 5, 6 and 9 has been reported, but this study added the LC-MS, Fourier Transform Infrared (FTIR) and NMR data for additional characterization. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Range Finding 14-Day and 90-Day Subchronic Feeding Studies with N,N-Dipropylcyclohexanecarboxamide in Rats. Phase 4.

DTIC Science & Technology

1986-12-01

Y CLS$1F-.AT N OF THIS...1 MN cD jO 0 -O Ocn00 ~ c" W) 400’ rno n + a9 .9 .i , vi 4 -W cm C44. y c 000 CD %D 1% CD-. U 4 CnN C! - N ON N N TV o 00 e~. r, ML 4r WL ne 0...to N D N4 ’aN N " Nf Y N Nm 00 1C’ bq D Wc iG f". rC W C4 No N N D On ’-0 0 0 f" .4l cc W.4 LoP doE N 04 In Ins. +. V. 0 0 fn 10 C Go 0D C 00’ 4o

Isoelectric point and adsorption activity of porous g-C3N4

NASA Astrophysics Data System (ADS)

Zhu, Bicheng; Xia, Pengfei; Ho, Wingkei; Yu, Jiaguo

2015-07-01

The isoelectric point (IEP) is an important physicochemical parameter of many compounds, such as oxides, hydroxides, and nitrides, and can contribute to estimation of the surface charges of compound particles at various pH conditions. In this work, three types of graphitic carbon nitrides (g-C3N4) were synthesized by directly heating melamine, thiourea, and urea. The prepared samples showed different microstructures and IEPs that influenced their adsorption activity. Differences in microstructure resulted from the various precursors used during synthesis. The IEPs of the obtained g-C3N4 were measured to be approximately 4-5, which is due to the equilibrium of chemical reactions between hydrogen ions, hydroxyl ions, and amine groups on the g-C3N4 surface. The IEP of g-C3N4 prepared from thiourea was lower than those of the corresponding samples prepared from melamine and urea. The adsorption activity of methylene blue on g-C3N4 prepared from urea and thiourea was excellent, which indicates that g-C3N4 is a promising adsorbent. This work provides a useful reference for choosing precursors with which to prepare g-C3N4 and combining g-C3N4 with other compounds in solution.

Crystal structure of bis-(benzyl-amine-κN)[5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinato-κ(4) N]iron(II) n-hexane monosolvate.

PubMed

Dhifaoui, Selma; Harhouri, Wafa; Bujacz, Anna; Nasri, Habib

2016-01-01

In the title compound, [Fe(II)(C44H24Cl4N4)(C6H5CH2NH2)2]·C6H14 or [Fe(II)(TPP-Cl)(BzNH2)2]·n-hexane [where TPP-Cl and BzNH2 are 5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinate and benzyl-amine ligands, respectively], the Fe(II) cation lies on an inversion centre and is octa-hedrally coordinated by the four pyrrole N atoms of the porphyrin ligand in the equatorial plane and by two amine N atoms of the benzyl-amine ligand in the axial sites. The crystal structure also contains one inversion-symmetric n-hexane solvent mol-ecule per complex mol-ecule. The average Fe-Npyrrole bond length [1.994 (3) Å] indicates a low-spin complex. The crystal packing is sustained by N-H⋯Cl and C-H⋯Cl hydrogen-bonding inter-actions and by C-H⋯π inter-molecular inter-actions, leading to a three-dimensional network structure.

Synthesis, spectral, thermal and antimicrobial studies of transition metal complexes of 14-membered tetraaza[N4] macrocyclic ligand

NASA Astrophysics Data System (ADS)

Shankarwar, Sunil G.; Nagolkar, Bhagwat B.; Shelke, Vinod A.; Chondhekar, Trimbak K.

2015-06-01

A series of metal complexes of Mn(II), Co(II), Ni(II), Cu(II), have been synthesized with newly synthesized biologically active macrocyclic ligand. The ligand was synthesized by condensation of β-diketone 1-(4-chlorophenyl)-3-(2-hydroxyphenyl)propane-1,3-dione and o-phenylene diamine. All the complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, 1H-NMR, UV-Vis spectroscopy and mass spectroscopy. From the analytical data, stoichiometry of the complexes was found to be 1:2 (metal:ligand). Thermal behavior (TG/DTA) and kinetic parameters suggest more ordered activated state in complex formation. All the complexes are of high spin type and six coordinated. On the basis of IR, electronic spectral studies and magnetic behavior, an octahedral geometry has been assigned to these complexes. The antibacterial and antifungal activities of the ligand and its metal complexes, has been screened in vitro against Staphylococcus aureus, Escherichia coli and Aspergillus niger, Trichoderma respectively.

Synthesis and Characterization of Selected 4,4'-Diaminoalkoxyazobenzenes

EPA Science Inventory

The role of the -N(CH2CH20H)2 group in producing a mutagenic response from 4-«3-(2h) Uroxyethoxy)4-amino)phenylazo)-N,N-bis(2-hydroxyethyl)-aniline has been investigated. To accomplish this goal, a group ofsubstituted 4,4'-diaminoazobenzene dyes was synthesized, and their struct...

Discovery of 4-anilino-N-methylthieno[3,2-d]pyrimidines and 4-anilino-N-methylthieno[2,3-d]pyrimidines as potent apoptosis inducers.

PubMed

Kemnitzer, William; Sirisoma, Nilantha; May, Chris; Tseng, Ben; Drewe, John; Cai, Sui Xiong

2009-07-01

We report the discovery of N-((benzo[d][1,3]dioxol-5-yl)methyl)-6-phenylthieno[3,2-d]pyrimidin-4-amine (2a) as an apoptosis inducer using our proprietary cell- and caspase-based ASAP HTS assay, and SAR study of HTS hit 2a which led to the discovery of 4-anilino-N-methylthieno[3,2-d]pyrimidines and 4-anilino-N-methylthieno[2,3-d]pyrimidines as potent apoptosis inducers. Compounds 5d and 5e were the most potent with EC(50) values of 0.008 and 0.004microM in T47D human breast cancer cells, respectively. Compound 5d was found to be highly active in the MX-1 breast cancer model. Functionally, compounds 5d and 5e both induced apoptosis through inhibition of tubulin polymerization.

4-N-Hydroxy-4-[1-(sulfonyl)piperidin-4-yl]-butyramides as HDAC inhibitors.

PubMed

Rossi, Cristina; Fincham, Christopher I; D'Andrea, Piero; Porcelloni, Marina; Ettorre, Alessandro; Mauro, Sandro; Bigioni, Mario; Binaschi, Monica; Maggi, Carlo A; Nardelli, Federica; Parlani, Massimo; Fattori, Daniela

2011-11-15

A series of N-substituted 4-alkylpiperidine hydroxamic acids, corresponding to the basic structure of histone deacetylase (HDAC) inhibitors (zinc binding moiety-linker-capping group) has been previously reported by our group. Linker length and aromatic capping group connection were systematically varied to find the optimal geometric parameters. A new series of submicromolar inhibitors was thus identified, which showed antiproliferative activity on HCT-116 colon carcinoma cells. We report here the second part of the strategy used in our research group to find a new class of HDAC inhibitors, namely the SAR study for the compounds bearing a sulfonyl group on the piperidine nitrogen. In the present work, we have considered both sulfonamides and sulfonyl ureas. Copyright © 2011 Elsevier Ltd. All rights reserved.

Enhanced photo-Fenton-like process over Z-scheme CoFe2O4/g-C3N4 Heterostructures under natural indoor light.

PubMed

Yao, Yunjin; Wu, Guodong; Lu, Fang; Wang, Shaobin; Hu, Yi; Zhang, Jie; Huang, Wanzheng; Wei, Fengyu

2016-11-01

Low-cost catalysts with high activity and stability toward producing strongly oxidative species are extremely desirable, but their development still remains a big challenge. Here, we report a novel strategy for the synthesis of a magnetic CoFe 2 O 4 /C 3 N 4 hybrid via a simple self-assembly method. The CoFe 2 O 4 /C 3 N 4 was utilized as a photo-Fenton-like catalyst for degradation of organic dyes in the presence of H 2 O 2 under natural indoor light irradiation, a green and energy-saving approach for environmental cleaning. It was found the CoFe 2 O 4 /C 3 N 4 hybrid with a CoFe 2 O 4 : g-C 3 N 4 mass ratio of 2:1 can completely degrade Rhodamine B nearly 100 % within 210 min under room-light irradiation. The effects of the amount of H 2 O 2 (0.01-0.5 M), initial dye concentration (5-20 mg/L), solution pH (3.08-10.09), fulvic acid concentration (5-50 mg/L), different dyes and catalyst stability on the organic dye degradation were investigated. The introduction of CoFe 2 O 4 on g-C 3 N 4 produced an enhanced separation efficiency of photogenerated electron - hole pairs by a Z-scheme mechanism between the interfaces of g-C 3 N 4 and CoFe 2 O 4 , leading to an excellent activity as compared with either g-C 3 N 4 or CoFe 2 O 4 and their mixture. This study demonstrates an efficient way to construct the low-cost magnetic CoFe 2 O 4 /C 3 N 4 heterojunction as a typical Z-scheme system in environmental remediation.

Crystal structure of poly[di­aqua­(μ2-benzene-1,4-di­carboxyl­ato-κ2 O 1:O 4)(μ2-benzene-1,4-di­carboxyl­ato-κ4 O 1,O 1′:O 4,O 4′)bis­(μ2-3,3′,5,5′-tetra­methyl-4,4′-bi­pyrazole-κ2 N:N′)dinickel(II)

PubMed Central

Wu, Chao; Cao, Peng

2015-01-01

The asymmetric unit of the polymeric title compound, [Ni(C8H4O4)(C10H14N4)(H2O)]n, contains one Ni2+ cation, one coordinating water mol­ecule, one 3,3′,5,5′-tetra­methyl-4,4′-bi­pyrazole ligand and half each of two benzene-1,4-di­carboxyl­ate anions, the other halves being generated by inversion symmetry. The Ni2+ cation exhibits an octa­hedral N2O4 coordination sphere defined by the O atoms of the water mol­ecule and two different anions and the N atoms of two symmetry-related N-heterocycles. The N-heterocycles and both anions bridge adjacent Ni2+ cations into a three-dimensional network structure, with one of the anions in a bis-bidentate and the other in a bis-monodentate bridging mode. N—H⋯O and O—H⋯O hydrogen bonds between the N-heterocycles and water mol­ecules as donor groups and the carboxyl­ate O atoms as acceptor groups consolidate the crystal packing. PMID:26090165

Narrowing the gap: from semiconductor to semimetal in the homologous series of rare-earth zinc arsenides RE(2-y)Zn4As4·n(REAs) and Mn-substituted derivatives RE(2-y)Mn(x)Zn(4-x)As4·n(REAs) (RE = La-Nd, Sm, Gd).

PubMed

Lin, Xinsong; Tabassum, Danisa; Mar, Arthur

2015-12-14

A homologous series of ternary rare-earth zinc arsenides, prepared by reactions of the elements at 750 °C, has been identified with the formula RE(2-y)Zn4As4·n(REAs) (n = 2, 3, 4) for various RE members. They adopt trigonal structures: RE(4-y)Zn4As6 (RE = La-Nd), space group R3̄m1, Z = 3; RE(5-y)Zn4As7 (RE = Pr, Nd, Sm, Gd), space group P3̄m1, Z = 1; RE(6-y)Zn4As8 (RE = La-Nd, Sm, Gd), space group R3̄m1, Z = 3. The Zn atoms can be partially substituted by Mn atoms, resulting in quaternary derivatives RE(2-y)Mn(x)Zn(4-x)As4·n(REAs). Single-crystal structures were determined for nine ternary and quaternary arsenides RE(2-y)M4As4·n(REAs) (M = Mn, Zn) as representative examples of these series. The structures are built by stacking close-packed nets of As atoms, sometimes in very long sequences, with RE atoms occupying octahedral sites and M atoms occupying tetrahedral sites, resulting in an intergrowth of [REAs] and [M2As2] slabs. The recurring feature of all members of the homologous series is a sandwich of [M2As2]-[REAs]-[M2As2] slabs, while rocksalt-type blocks of [REAs] increase in thickness between these sandwiches with higher n. Similar to the previously known related homologous series REM(2-x)As2·n(REAs) which is deficient in M, this new series RE(2-y)M4As4·n(REAs) exhibits deficiencies in RE to reduce the electron excess that would be present in the fully stoichiometric formulas. Enthalpic and entropic factors are considered to account for the differences in site deficiencies in these two homologous series. Band structure calculations indicate that the semiconducting behaviour of the parent n = 0 member (with CaAl2Si2-type structure) gradually evolves, through a narrowing of the gap between valence and conduction bands, to semimetallic behaviour as the number of [REAs] blocks increases, to the limit of n = ∞ for rocksalt-type REAs.

Theoretical Studies of Routes to Synthesis of Tetrahedral N4

NASA Technical Reports Server (NTRS)

Lee, Timothy J.; Dateo, Christopher E.

2007-01-01

A paper [Chem. Phys. Lett. 345, 295 (2001)] describes theoretical studies of excited electronic states of nitrogen molecules, with a view toward utilizing those states in synthesizing tetrahedral N4, or Td N4 a metastable substance under consideration as a high-energy-density rocket fuel. Several ab initio theoretical approaches were followed in these studies, including complete active space self-consistent field (CASSCF), state-averaged CASSCF (SA-CASSCF), singles configuration interaction (CIS), CIS with second-order and third-order correlation corrections [CIS(D) and CIS(3)], and linear response singles and doubles coupled-cluster (LRCCSD). Standard double zeta polarized and triple zeta double polarized one-particle basis sets were used. The CASSCF calculations overestimated the excitation energies, while SACASSCF calculations partly corrected these overestimates. The accuracy of the CIS calculations varied, depending on the particular state, while the CIS(D), CIS(3), and LRCCSD results were in generally good agreement. The energies of the lowest six excited singlet states of Td N4 as calculated by the LRCCSD were compared with the energies of possible excited states of N2 + N2 fragments, leading to the conclusion that the most likely route for synthesis of Td N4 would involve a combination of two bound quintet states of N2.

Conformational organizations of G-quadruplexes composed of d(G(4)T(n))(3)G(4).

PubMed

Wong, Wan Chi; Zhuang, Jinyi; Ng, Selina Ling Ling; New, Lilian Li Lin; Hiew, Shuhui; Guo, Juanjuan; Yang, Zhaoqi; Li, Tianhu

2010-08-01

Structural polymorphism is one of the important issues with regard to G-quadruplexes because the structural diversity may significantly affect their biological functions in vivo and their physical property in nano-material. A series of oligonucleotides with four repeat guanines sequence [d(G(4)T(n))(3)G(4) (n=1-6)] were designed. In this study, the effects of loop length on the formation of structures of G-quadruplex were investigated through the result of CD (circular dichroism) and 20% non-denatured polyacrylamide gel electrophoresis. Our studies demonstrate that the length of loop in 100mM KCl solution could predict the conformation of G-quadruplex. Copyright 2010 Elsevier Ltd. All rights reserved.

AdS/CFT beyond the N = 4 SYM paradigm

NASA Astrophysics Data System (ADS)

Pomoni, Elli

In this thesis we present studies in the AdS/CFT correspondence that intend to push the present knowledge beyond the N = 4 super Yang-Mills (SYM) paradigm. The first part is concerned with the study of non-supersymmetric deformations of N = 4 SYM (which still are in the N = 4 universality class). For non-supersymmetric CFT's at Large N we explore the correspondence between string theory tachyons in the bulk and instabilities on the boundary effective action. The operators dual to AdS tachyons have anomalous dimensions that are purely complex numbers. We give a prescription for calculating the mass of the tachyon from the field theory side. Moreover, we apply this general dictionary to the case of intersecting D7 flavor branes in AdS 5 x S5 and obtain the mass of the open string tachyon that is dual to the instability in the mesonic sector of the theory. In the second part we present work aiming at finding string theory duals for gauge theories beyond the N = 4 universality class, i.e. theories that have genuinely less supersymmetry and unquenched flavor. Arguably the next simplest example after N = 4 SYM is N = 2 SU(Nc) SYM coupled to Nf = 2Nc fundamental hypermultiplets. The theory admits a Veneziano expansion of large Nc and large Nf, with Nf/Nc and lambda = g2Nc kept fixed. The topological structure of large N diagrams invites a general conjecture: the flavor-singlet sector of a gauge theory in the Veneziano limit is dual to a closed string theory. We present the one-loop Hamiltonian for the scalar sector of N = 2 superconformal QCD and study this integrability of the theory. Furthermore, we explore the chiral spectrum of the protected operators of the theory using the one-loop anomalous dimensions and, additionally, by studying the index of the theory. We finally search for possible AdS dual trying to match the chiral spectrum. We conclude that the string dual is a sub-critical background containing both an AdS 5 and an S1 factor.

NATb/NAT1*4 promotes greater arylamine N-acetyltransferase 1 mediated DNA adducts and mutations than NATa/NAT1*4 following exposure to 4-aminobiphenyl

PubMed Central

Millner, Lori M.; Doll, Mark A.; Cai, Jian; States, J. Christopher; Hein, David W.

2011-01-01

N -acetyltransferase 1 (NAT1) is a phase II metabolic enzyme responsible for the biotransformation of aromatic and heterocyclic amine carcinogens such as 4-aminobiphenyl (ABP). NAT1 catalyzes N-acetylation of arylamines as well as the O-acetylation of N-hydroxylated arylamines. O-acetylation leads to the formation of electrophilic intermediates that result in DNA adducts and mutations. NAT1 is transcribed from a major promoter, NATb, and an alternative promoter, NATa, resulting in mRNAs with distinct 5′-untranslated regions (UTR). NATa mRNA is expressed primarily in the kidney, liver, trachea and lung while NATb mRNA has been detected in all tissues studied. To determine if differences in 5′-UTR have functional effect upon NAT1 activity and DNA adducts or mutations following exposure to ABP, pcDNA5/FRT plasmid constructs were prepared for transfection of full length human mRNAs including the 5′-UTR derived from NATa or NATb, the open reading frame, and 888 nucleotides of the 3′-UTR. Following stable transfection of NATb/NAT1*4 or NATa/NAT1*4 into nucleotide excision repair (NER) deficient Chinese hamster ovary cells, N-acetyltransferase activity (in vitro and in situ), mRNA, and protein expression were higher in NATb/NAT1*4 than NATa/NAT1*4 transfected cells (p<0.05). Consistent with NAT1 expression and activity, ABP-induced DNA adducts and hypoxanthine phosphoribosyl transferase mutants were significantly higher (p<0.05) in NATb/NAT1*4 than in NATa/NAT1*4 transfected cells following exposure to ABP. These differences observed between NATa and NATb suggest that the 5′-UTRs are differentially regulated. PMID:21837760

N-(4-Meth-oxy-phen-yl)-6-methyl-2-phenyl-5-{[4-(tri-fluoro-meth-yl)anilino]meth-yl}pyrimidin-4-amine.

PubMed

Cieplik, Jerzy; Pluta, Janusz; Bryndal, Iwona; Lis, Tadeusz

2013-11-27

The title compound, C26H23F3N4O, crystallizes with two symmetry-independent mol-ecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the meth-oxy-phenyl ring. The -CF3 group of mol-ecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, meth-oxy-phenyl and tri-fluoro-methyl-phenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2)°, respectively, in mol-ecule A, and 9.3 (2), 5.3 (2) and 79.7 (2)° in mol-ecule B. An intra-molecular N-H⋯N hydrogen bond occurs in each mol-ecule. In the crystal, two crystallographically independent mol-ecules associate into a dimer via a pair of N-H⋯N hydrogen bonds, with a resulting R 2 (2)(12) ring motif and π-π stacking inter-actions [centroid-centroid distance = 3.517 (4) Å] between the pyrimidine rings. For the A mol-ecules, there are inter-molecular C-H⋯O hydrogen bonds between an aryl C atom of meth-oxy-phenyl ring and a meth-oxy O atom of an adjacent mol-ecule. A similar inter-action is lacking in the B mol-ecules.

Facile synthesis of Fe3O4/g-C3N4/HKUST-1 composites as a novel biosensor platform for ochratoxin A.

PubMed

Hu, Shuisheng; Ouyang, Wenjun; Guo, Longhua; Lin, Zhenyu; Jiang, Xiaohua; Qiu, Bin; Chen, Guonan

2017-06-15

A fluorescent biosensor for ochratoxin A was fabricated on the basis of a new nanocomposite (Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites). Fe 3 O 4 /g-C 3 N 4 /HKUST-1 was synthesized in this work for the first time, which combined HKUST-1 with g-C 3 N 4 to improve its chemical stability. Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites have strong adsorption capacity for dye-labeled aptamer and are able to completely quench the fluorescence of the dye through the photoinduced electron transfer (PET) mechanism. In the presence of ochratoxin A (OTA), it can bind with the aptamer with high affinity, causing the releasing of the dye-labeled aptamer from the Fe 3 O 4 /g-C 3 N 4 /HKUST-1 and therefore results in the recovery of fluorescence. The fluorescence intensity of the biosensor has a linear relationship with the OTA concentration in the range of 5.0-160.0ng/mL. The LOD of sensor is 2.57ng/mL (S/N=3). This fluorescence sensor based on the Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites has been applied to detect OTA in corn with satisfying results. Copyright © 2016. Published by Elsevier B.V.

Pressure-induced stable BeN4 as a high-energy density material

NASA Astrophysics Data System (ADS)

Zhang, Shoutao; Zhao, Ziyuan; Liu, Lulu; Yang, Guochun

2017-10-01

Polynitrogens are the ideal rocket fuels or propellants. Due to strong triple N≡N bond in N2, the direct polymerization of nitrogen is rather difficult (i.e. extreme high temperature and high pressure). However, the use of nitrides as precursors or the reaction of N2 with other elements has been proved to be an effective way to obtain polynitrogens. Here, with assistance of the advanced first-principles swarm-intelligence structure searches, we found that P 1 bar -BeN4, containing infinite zigzag-like polymeric nitrogen chains, can be synthesized by compressing the mixture of Be3N2 and N2 at 25.4 GPa, which is greatly lower than 110 GPa for synthesizing cubic gauche nitrogen and other polynitrogen compounds (e.g. bulk CNO at 52 GPa and SN4 at 49 GPa). Its structural stability can be attributed to the coexistence of ionic Be-N and covalent N-N bonds. Intriguingly, this phase has high kinetic stability and remains metastable at ambient pressure. The exceptional properties, including high energy density (3.60 kJ g-1), high nitrogen content (86.1%), high dynamical stability, and low polymerization pressure, make P 1 bar -structured BeN4 a promising high energy material. Infinite nitrogen chains in P 1 bar -BeN4 transform to N10 rings network in P21/c phase at 115.1 GPa. P 1 bar -BeN4 is metallic, while P21/c-BeN4 is an insulator.

Formation of Different Si3N4 Nanostructures by Salt-Assisted Nitridation.

PubMed

Liu, Xiongzhang; Guo, Ran; Zhang, Sengjing; Li, Qingda; Saito, Genki; Yi, Xuemei; Nomura, Takahiro

2018-04-11

Silicon nitride (Si 3 N 4 ) products with different nanostructure morphologies and different phases for Si 3 N 4 ceramic with high thermal conductivity were synthesized by a direct nitriding method. NaCl and NH 4 Cl were added to raw Si powders, and the reaction was carried out under a nitrogen gas flow of 100 mL/min. The phase composition and morphologies of the products were systemically characterized by X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. At 1450 °C, the NaCl content was 30 wt %, the NH 4 Cl content was 3 wt %, and the maximum α-Si 3 N 4 content was 96 wt %. The process of Si nitridation can be divided into three stages by analyzing the reaction schemes: in the first stage (25-900 °C), NH 4 Cl decomposition and the generation of stacked amorphous Si 3 N 4 occurs; in the second stage (900-1450 °C), NaCl melts and Si 3 N 4 generates; and in the third stage (>1450 °C), α-Si 3 N 4 → β-Si 3 N 4 phase change and the evaporation of NaCl occurs. The products are made of two layers: a thin upper layer of nanowires containing different nanostructures and a lower layer mainly comprising fluffy, blocky, and short needlelike products. The introduction of NaCl and NH 4 Cl facilitated the evaporation of Si powders and the decomposition of Al 2 O 3 from porcelain boat and furnace tube, which resulted in the mixing of N 2 , O 2 , Al 2 O, and Si vapors and generated Al x Si y O z nanowires with rough surfaces and lead to thin Si 3 N 4 nanowires, nanobranches by the vapor-solid (VS), vapor-liquid-solid (VLS), and the double-stage VLS base and VS tip growth mechanisms.

Aryl-1H-imidazole[4,5f][1,10]phenanthroline Cu(II) complexes: Electrochemical and DNA interaction studies.

PubMed

Rajebhosale, Bharati S; Dongre, Shivali N; Deshpande, Sameer S; Kate, Anup N; Kumbhar, Anupa A

2017-10-01

The reaction of aryl imidazo[4,5f] [1,10]phenanthrolines with Cu(NO 3 ) 2 lead to the formation of Cu(II) complexes of the type [Cu(L)(NO 3 ) 2 ] where L=PIP, 2-(phenyl) [4,5f] imidazo phenanthroline; HPIP=2-(2-hydroxyphenyl)imidazo [4,5f] phenanthroline and NIP=2-(naphthyl) [4,5f] imidazo phenanthroline. The interaction of these complexes with calf thymus DNA has been studied using viscosity measurements, UV-visible and fluorescence spectroscopy. Chemical nuclease activity of these complexes has also been investigated. All complexes cleave DNA via oxidative pathway involving singlet oxygen. Molecular docking studies revealed that these complexes bind to DNA through minor groove. Copyright © 2017 Elsevier Inc. All rights reserved.

N-(2-{[5-Bromo-2-(morpholin-4-yl)pyrimidin-4-yl]sulfan­yl}-4-meth­oxy­phen­yl)-4-chloro­benzene­sulfonamide

PubMed Central

Kumar, Mohan; Mallesha, L.; Sridhar, M. A.; Kapoor, Kamini; Gupta, Vivek K.; Kant, Rajni

2012-01-01

In the title compound, C21H20BrClN4O4S2, the benzene rings bridged by the sulfonamide group are tilted relative to each other by a dihedral angle of 70.2 (1)° and the dihedral angle between the sulfur-bridged pyrimidine and benzene rings is 69.5 (1)°. The mol­ecular conformation is stabilized by a weak intra­molecular π–π stacking inter­action between the pyrimidine and the 4-chloro­benzene rings [centroid–centroid distance = 3.978 (2) Å]. The morpholine ring adopts a chair conformation. In the crystal, mol­ecules are linked into inversion dimers by pairs of C—H⋯N hydrogen bonds and these dimers are further connected by N—H⋯O hydrogen bonds, forming a tape along the a axis. PMID:22969673

Crystal structure of poly[[μ-4-(hy-droxy-meth-yl)pyridine-κ(2) N:O][4-(hy-droxy-meth-yl)pyridine-κN](μ-thio-cyanato-κ(2) N:S)(thio-cyanato-κN)cadmium].

PubMed

Werner, Julia; Jess, Inke; Näther, Christian

2015-06-01

The crystal structure of the title compound, [Cd(NCS)2(C6H7NO)2] n is made up of Cd(2+) cations that are coordinated by three thio-cyanate ligands and three 4-(hy-droxy-meth-yl)pyridine ligands within distorted N4OS octa-hedra. The asymmetric unit consists of one Cd(2+) cation, two thio-cyanate anions and two 4-(hy-droxy-meth-yl)pyridine ligands in general positions. Two Cd(2+) cations are linked by two μ-1,3 N- and S-bonding thio-ycanate anions into dimers which are further linked into branched chains along [100] by two μ-1,6 N- and O-bonding 4-(hy-droxy-meth-yl)pyridine ligands. One additional N-bonded 4-(hy-droxy-meth-yl)pyridine ligand and one additional N-bonded thio-cyanate anion are only terminally bonded to the metal cation. Inter-chain O-H⋯S hydrogen bonds between the hy-droxy H atoms and one of the thio-cyanate S atoms connect the chains into a three-dimensional network.

Tris(4,4′-bi-1,3-thia­zole-κ2 N,N′)iron(II) tetra­bromidoferrate(III) bromide

PubMed Central

Abedi, Anita; Amani, Vahid; Safari, Nasser

2011-01-01

In the [Fe(4,4′-bit)3]2+ (4,4′-bit is 4,4′-bi-1,3-thia­zole) cation of the title compound, [Fe(C6H4N2S2)3][FeBr4]Br, the FeII atom (3 symmetry) is six-coordinated in a distorted octa­hedral geometry by six N atoms from three 4,4′-bit ligands. In the [FeBr4]− anion, the FeIII atom (3 symmetry) is four-coordinated in a distorted tetra­hedral geometry. In the crystal, inter­molecular C—H⋯Br hydrogen bonds and Br⋯π inter­actions [Br⋯centroid distances = 3.562 (3) and 3.765 (2) Å] link the cations and anions, stabilizing the structure. PMID:21522247

Highly efficient alkane oxidation catalyzed by [Mn(V)(N)(CN)4](2-). Evidence for [Mn(VII)(N)(O)(CN)4](2-) as an active intermediate.

PubMed

Ma, Li; Pan, Yi; Man, Wai-Lun; Kwong, Hoi-Ki; Lam, William W Y; Chen, Gui; Lau, Kai-Chung; Lau, Tai-Chu

2014-05-28

The oxidation of various alkanes catalyzed by [Mn(V)(N)(CN)4](2-) using various terminal oxidants at room temperature has been investigated. Excellent yields of alcohols and ketones (>95%) are obtained using H2O2 as oxidant and CF3CH2OH as solvent. Good yields (>80%) are also obtained using (NH4)2[Ce(NO3)6] in CF3CH2OH/H2O. Kinetic isotope effects (KIEs) are determined by using an equimolar mixture of cyclohexane (c-C6H12) and cyclohexane-d12 (c-C6D12) as substrate. The KIEs are 3.1 ± 0.3 and 3.6 ± 0.2 for oxidation by H2O2 and Ce(IV), respectively. On the other hand, the rate constants for the formation of products using c-C6H12 or c-C6D12 as single substrate are the same. These results are consistent with initial rate-limiting formation of an active intermediate between [Mn(N)(CN)4](2-) and H2O2 or Ce(IV), followed by H-atom abstraction from cyclohexane by the active intermediate. When PhCH2C(CH3)2OOH (MPPH) is used as oxidant for the oxidation of c-C6H12, the major products are c-C6H11OH, c-C6H10O, and PhCH2C(CH3)2OH (MPPOH), suggesting heterolytic cleavage of MPPH to generate a Mn═O intermediate. In the reaction of H2O2 with [Mn(N)(CN)4](2-) in CF3CH2OH, a peak at m/z 628.1 was observed in the electrospray ionization mass spectrometry, which is assigned to the solvated manganese nitrido oxo species, (PPh4)[Mn(N)(O)(CN)4](-)·CF3CH2OH. On the basis of the experimental results the proposed mechanism for catalytic alkane oxidation by [Mn(V)(N)(CN)4](2-)/ROOH involves initial rate-limiting O-atom transfer from ROOH to [Mn(N)(CN)4](2-) to generate a manganese(VII) nitrido oxo active species, [Mn(VII)(N)(O)(CN)4](2-), which then oxidizes alkanes (R'H) via a H-atom abstraction/O-rebound mechanism. The proposed mechanism is also supported by density functional theory calculations.

Low-energy collision-induced fragmentation of negative ions derived from ortho-, meta-, and para-hydroxyphenyl carbaldehydes, ketones, and related compounds.

PubMed

Attygalle, Athula B; Ruzicka, Josef; Varughese, Deepu; Bialecki, Jason B; Jafri, Sayed

2007-09-01

Collision-induced dissociation (CID) mass spectra of anions derived from several hydroxyphenyl carbaldehydes and ketones were recorded and mechanistically rationalized. For example, the spectrum of m/z 121 ion of deprotonated ortho-hydroxybenzaldehyde shows an intense peak at m/z 93 for a loss of carbon monoxide attributable to an ortho-effect mediated by a charge-directed heterolytic fragmentation mechanism. In contrast, the m/z 121 ion derived from meta and para isomers undergoes a charge-remote homolytic cleavage to eliminate an *H and form a distonic anion radical, which eventually loses CO to produce a peak at m/z 92. In fact, for the para isomer, this two-step homolytic mechanism is the most dominant fragmentation pathway. The spectrum of the meta isomer on the other hand, shows two predominant peaks at m/z 92 and 93 representing both homolytic and heterolytic fragmentations, respectively. (18)O-isotope-labeling studies confirmed that the oxygen in the CO molecule that is eliminated from the anion of meta-hydroxybenzaldehyde originates from either the aldehydic or the phenolic group. In contrast, anions of ortho-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde, both of which show two consecutive CO eliminations, specifically lose the carbonyl oxygen first, followed by that of the phenolic group. Anions from 2-hydroxyphenyl alkyl ketones lose a ketene by a hydrogen transfer predominantly from the alpha position. Interestingly, a very significant charge-remote 1,4-elimination of a H(2) molecule was observed from the anion derived from 2,4-dihydroxybenzaldehyde. For this mechanism to operate, a labile hydrogen atom should be available on the hydroxyl group adjacent to the carbaldehyde functionality.

Reintroduction of highly pathogenic avian influenza A/H5N8 virus of clade 2.3.4.4. in Russia.

PubMed

Marchenko, Vasiliy Y; Susloparov, Ivan M; Komissarov, Andrey B; Fadeev, Artem; Goncharova, Nataliya I; Shipovalov, Andrey V; Svyatchenko, Svetlana V; Durymanov, Alexander G; Ilyicheva, Tatyana N; Salchak, Lyudmila K; Svintitskaya, Elena P; Mikheev, Valeriy N; Ryzhikov, Alexander B

2017-05-01

In the spring of 2016, a loss of wild birds was observed during the monitoring of avian influenza virus activity in the Republic of Tyva. That outbreak was caused by influenza H5N8 virus of clade 2.3.4.4. In the fall, viruses of H5N8 clade 2.3.4.4 were propagated in European countries. This paper presents some results of analysis of the virus strains isolated during the spring and fall seasons in 2016 in the Russian Federation. The investigated strains were highly pathogenic for mice, and some of their antigenic and genetic features differed from those of an H5N8 strain that circulated in 2014 in Russia.

Photocatalytic decomposition of N2O over TiO2/g-C3N4 photocatalysts heterojunction

NASA Astrophysics Data System (ADS)

Kočí, K.; Reli, M.; Troppová, I.; Šihor, M.; Kupková, J.; Kustrowski, P.; Praus, P.

2017-02-01

TiO2/g-C3N4 photocatalysts with the various TiO2/g-C3N4 weight ratios from 1:2 to 1:6 were fabricated by mechanical mixing in water suspension followed by calcination. Pure TiO2 was prepared by thermal hydrolysis and pure g-C3N4 was prepared from commercial melamine by thermal annealing at 620 °C. All the nanocomposites were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, photoelectrochemical measurements and nitrogen physisorption. The prepared mixtures along with pure TiO2 and g-C3N4 were tested for the photocatalytic decomposition of nitrous oxide under UVC (λ = 254 nm), UVA (λ = 365 nm) and Vis (λ > 400 nm) irradiation. The TiO2/g-C3N4 nanocomposites showed moderate improvement compared to pure g-C3N4 but pure TiO2 proved to be a better photocatalyst under UVC irradiation. However, under UVA irradiation conditions, the photocatalytic activity of TiO2/g-C3N4 (1:2) nanocomposite exhibited an increase compared to pure TiO2. Nevertheless, further increase of g-C3N4 amount leads/led to a decrease in reactivity. These results are suggesting the nanocomposite with the optimal weight ratio of TiO2 and g-C3N4 have shifted absorption edge energy towards longer wavelengths and decreased the recombination rate of charge carriers compared to pure g-C3N4. This is probably due to the generation of heterojunction on the TiO2/g-C3N4 interface.

Synthesis, crystal structure, characterization and antifungal activity of 3,4-diaryl-1H-Pyrazoles derivatives

NASA Astrophysics Data System (ADS)

Zhang, Jin; Tan, Da-Jin; Wang, Tao; Jing, Si-Si; Kang, Yang; Zhang, Zun-Ting

2017-12-01

A series of 3,4-diaryl-1H-pyrazoles derivatives were designed and synthesized by the reaction of 3-heteroarylchromones and 3-phenylchromones with hydrazine hydrate in good yields. All of those compounds were characterized by 1H NMR, 13C NMR, IR, and HRMS. Moreover, 3-(2,4-dihydroxyphenyl)-4-(4-hydroxyphenyl)-1H-pyrazole and 3-(2,4-dihydroxy phenyl)-4-(4-methoxyphenyl)-1H-pyrazole were further conformed by the single crystal X-ray diffraction. In addition, the antifungal activity against five phytopathogenic fungi (Cytospora sp., Colletotrichum gloeosporioides, Botrytis cinerea, Alternaria solani and Fusarium solani) of 3,4-diaryl-1H-pyrazoles were evaluated. 3-(2-Hydroxy-4-isopropoxyphenyl)-4-phenyl-1H-pyrazole was more better and broader inhibitory effect on Cytospora sp., C. gloeosporioides, A. solani and Fusarium solani with IC50 values of 26.96, 28.84, 16.77 and 22.10 μg/mL, respectively. 4-(4-Fluorophenyl)-3-(2-hydroxy-4-methoxyphenyl)-1H-pyrazole exhibited fairly effective antifungal activity against Cytospora sp., C. gloeosporioides and A. solani with IC50 values of 11.91, 14.92 and 16.98 μg/mL, respectively.

Temperature-Dependent Electrical Characteristics of Au/Si3N4/4H n-SiC MIS Diode

NASA Astrophysics Data System (ADS)

Yigiterol, F.; Güllü, H. H.; Bayraklı, Ö.; Yıldız, D. E.

2018-03-01

Electrical characteristics of the Au/Si3N4/4H n-SiC metal-insulator-semiconductor (MIS) diode were investigated under the temperature, T , interval of 160-400 K using current-voltage (I-V), capacitance-voltage ( C {-} V ) and conductance-voltage ( G/ω {-} V ) measurements. Firstly, the Schottky diode parameters as zero-bias barrier height ( Φ_{B0} ) and ideality factor ( n ) were calculated according to the thermionic emission (TE) from forward bias I-V analysis in the whole working T . Experimental results showed that the values of Φ_{B0} were in increasing behavior with increasing T while n values decreased with inverse proportionality in n versus Φ_{{{{B}}0}} plot. Therefore, the non-ideal I-V behavior with inhomogeneous barrier height (BH) formation has been discussed under the assumption of Gaussian distribution (GD). From the GD of BHs, the mean BH was found to be about 1.40 eV with 0.1697 standard deviation and the modified Richardson constant A^{*} of this diode was obtained as 141.65 A/cm2 K2 in good agreement with the literature (the theoretical value of A^{*} is 137.21 A/cm2 K2). The relationship between Φ_{B0} and n showed an abnormal I-V behavior depending on T , and it was modeled by TE theory with GD of BH due to the effect in inhomogeneous BH at the interface. Secondly, according to Cheung's model, series resistance, R_{{S}} values were calculated in the T range of 160-400 K and these values were found to decrease with increasing T . Finally, the density of interface states, D_{{it}} was calculated and the T dependence of energy distribution of D_{{it}} profiles determined the forward I {-} V measurements by taking into account the bias dependence of the effective BH, Φ_{{e}} and n . D_{{it}} were also calculated according to the Hill-Coleman method from C {-} V and G/ω {-} V analysis. Furthermore, the variation of D_{{it}} as a function of frequency, f and T were determined.

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

Chenna, Ahmed; Gupta, Ramesh C.; Bonala, Radha R.

N2-(4-Hydroxyphenyl)-2'-deoxyguanosine-5'-O-DMT-3'-phosphoramidite has been synthesized and used to incorporate the N2-(4-hydroxyphenyl)-2'-dG (N2-4-HOPh-dG) into DNA, using solid-state synthesis technology. The key step to obtaining the xenonucleoside is a palladium (Xantphos-chelated) catalyzed N2-arylation (Buchwald-Hartwig reaction) of a fully protected 2'-deoxyguanosine derivative by 4-isobutyryloxybromobenzene. The reaction proceeded in good yield and the adduct was converted to the required 5'-O-DMT-3'-O-phosphoramidite by standard methods. The latter was used to synthesize oligodeoxynucleotides in which the N2-4-HOPh-dG adduct was incorporated site-specifically. The oligomers were purified by reverse-phase HPLC. Enzymatic hydrolysis and HPLC analysis confirmed the presence of this adduct in the oligomers.

Finding pathways to prepare Fe4N thin films at low substrate temperature

NASA Astrophysics Data System (ADS)

Seema, Gupta, Nitiand Mukul

2018-04-01

In Fe-N phase diagram the formation of Fe4N thin films occur in a very narrow region, specially below 573 K. Above this, the range of homogeneity for formation of Fe4N start to increase yielding more favorable conditions for formation of single phase Fe4N. However, when deposited at high substrate temperature (Ts) typically above 650 K, nitrogen (N) tends to diffuse out of the system yielding a N deficient phase. In this work, we attempt to find pathways to deposit Fe4N thin films at low Ts and successfully prepared single phase Fe4N thin films at Ts as low as 423 K. This was achieved by utilizing an underlayer of CrN. We find that such underlayer not only has close lattice matching with Fe4N, it also acts as a diffusion barrier for the film-substrate interface.

Charge-controlled switchable CO adsorption on FeN4 cluster embedded in graphene

NASA Astrophysics Data System (ADS)

Omidvar, Akbar

2018-02-01

Electrical charging of an FeN4 cluster embedded in graphene (FeN4G) is proposed as an approach for electrocatalytically switchable carbon monoxide (CO) adsorption. Using density functional theory (DFT), we found that the CO molecule is strongly adsorbed on the uncharged FeN4G cluster. Our results show that the adsorption energy of a CO molecule on the FeN4G cluster is dramatically decreased by introducing extra electrons into the cluster. Once the charges are removed, the CO molecule is spontaneously adsorbed on the FeN4G absorbent. In the framework of frontier molecular orbital (FMO) analysis, the enhanced sensitivity and reactivity of the FeN4G cluster towards the CO molecule can be interpreted in terms of interaction between the HOMO of CO molecule and the LUMO of FeN4G cluster. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the FeN4G nanomaterial is an excellent absorbent for controllable and reversible capture and release of the CO.

Reliably counting atomic planes of few-layer graphene (n > 4).

PubMed

Koh, Yee Kan; Bae, Myung-Ho; Cahill, David G; Pop, Eric

2011-01-25

We demonstrate a reliable technique for counting atomic planes (n) of few-layer graphene (FLG) on SiO(2)/Si substrates by Raman spectroscopy. Our approach is based on measuring the ratio of the integrated intensity of the G graphene peak and the optical phonon peak of Si, I(G)/I(Si), and is particularly useful in the range n > 4 where few methods exist. We compare our results with atomic force microscopy (AFM) measurements and Fresnel equation calculations. Then, we apply our method to unambiguously identify n of FLG devices on SiO(2) and find that the mobility (μ ≈ 2000 cm(2) V(-1) s(-1)) is independent of layer thickness for n > 4. Our findings suggest that electrical transport in gated FLG devices is dominated by carriers near the FLG/SiO(2) interface and is thus limited by the environment, even for n > 4.

The Coulomb Branch of 3d $${\\mathcal{N}= 4}$$ N = 4 Theories

DOE PAGES

Bullimore, Mathew; Dimofte, Tudor; Gaiotto, Davide

2017-06-03

We propose a construction for the quantum-corrected Coulomb branch of a general 3d gauge theory with N=4 supersymmetry, in terms of local coordinates associated with an abelianized theory. In a fixed complex structure, the holomorphic functions on the Coulomb branch are given by expectation values of chiral monopole operators. We construct the chiral ring of such operators, using equivariant integration over BPS moduli spaces. We also quantize the chiral ring, which corresponds to placing the 3d theory in a 2d Omega background. Then, by unifying all complex structures in a twistor space, we encode the full hyperkähler metric on themore » Coulomb branch. We verify our proposals in a multitude of examples, including SQCD and linear quiver gauge theories, whose Coulomb branches have alternative descriptions as solutions to Bogomolnyi and/or Nahm equations.« less

Psychotomimetic opiate receptors labeled and visualized with (+)-(/sup 3/H)3-(3-hydroxyphenyl)-N-(1-propyl)piperidine

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

Largent, B.L.; Gundlach, A.L.; Snyder, S.H.

1984-08-01

3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP) has been proposed as a selective dopamine autoreceptor agonist in the central nervous system. This report describes the pharmacology and localization of specific high-affinity binding sites for (+)-(/sup 3/H)3-PPP in brain. The drug specificity of (+)-(/sup 3/H)3-PPP binding is identical to that of sigma receptors, which may mediate psychotomimetic effects of some opiates. Haloperidol and the opioid derivatives, pentazocine, cyclazocine, and SKF 10,047 are potent inhibitors of (+)-(/sup 3/H)3-PPP binding. Stereoselectivity is exhibited for the (+) isomers of cyclazocine and SKF 10.047 at the sigma site, opposite to the stereoselectivity seen at ..mu.., sigma, and k opiate receptors.more » (+)-(/sup 3/H)3-PPP does not label dopamine receptors, as potent dopamine agonists and antagonists are weak inhibitors of binding and the localization of specific (+)-(/sup 3/H)3-PPP binding sites does not parallel that of dopamine neurons. Discrete localizations of (+)-(/sup 3/H)3-PPP binding sites in many brain areas including limbic, midbrain, brainstem, and cerebellar regions may explain psychotomimetic actions of opiates and behavior effects of 3-PPP. 41 references, 2 figures, 1 table.« less

N-(2-{[5-Bromo-2-(morpholin-4-yl)pyrimidin-4-yl]sulfan­yl}-4-meth­oxy­phen­yl)-4-methyl­benzene­sulfonamide

PubMed Central

Kant, Rajni; Gupta, Vivek K.; Kapoor, Kamini; Kumar, Mohan; Mallesha, L.; Sridhar, M. A.

2012-01-01

In the title compound, C22H23BrN4O4S2, the benzene rings bridged by the sulfonamide group are tilted relative to each other by 68.9 (1)° and the dihedral angle between the sulfur-bridged pyrimidine and benzene rings is 69.7 (1)°. The mol­ecular conformation is stabilized by a weak intra­molecular π–π stacking inter­action between the pyrimidine and the 4-methylbenzene rings [centroid–centroid distance = 3.934 (2) Å]. The morpholine ring adopts a chair conformation and is disordered over two positions with an occupancy ratio of 0.853 (6):0.147 (6). In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds into chains extending along the a axis and further, through C—H⋯N and C—H⋯O inter­actions, into a three-dimensional supramolecular structure. PMID:22905015

Structural, Electronic, and Thermodynamic Properties of Tetragonal t-SixGe3−xN4

PubMed Central

Han, Chenxi; Chai, Changchun; Fan, Qingyang; Yang, Jionghao; Yang, Yintang

2018-01-01

The structural, mechanical, anisotropic, electronic, and thermal properties of t-Si3N4, t-Si2GeN4, t-SiGe2N4, and t-Ge3N4 in the tetragonal phase are systematically investigated in the present work. The mechanical stability is proved by the elastic constants of t-Si3N4, t-Si2GeN4, t-SiGe2N4, and t-Ge3N4. Moreover, they all demonstrate brittleness, because B/G < 1.75, and v < 0.26. The elastic anisotropy of t-Si3N4, t-Si2GeN4, t-SiGe2N4, and t-Ge3N4 is characterized by Poisson’s ratio, Young’s modulus, the percentage of elastic anisotropy for bulk modulus AB, the percentage of elastic anisotropy for shear modulus AG, and the universal anisotropic index AU. The electronic structures of t-Si3N4, t-Si2GeN4, t-SiGe2N4, and t-Ge3N4 are all wide band gap semiconductor materials, with band gaps of 4.26 eV, 3.94 eV, 3.83 eV, and 3.25 eV, respectively, when using the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional. Moreover, t-Ge3N4 is a quasi-direct gap semiconductor material. The thermodynamic properties of t-Si3N4, t-Si2GeN4, t-SiGe2N4, and t-Ge3N4 are investigated utilizing the quasi-harmonic Debye model. The effects of temperature and pressure on the thermal expansion coefficient, heat capacity, Debye temperature, and Grüneisen parameters are discussed in detail. PMID:29518943

Synthesis and applications of [1-(15)N]-labeled 4,6-dimethyl-4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide as a useful tool for mechanistic investigations.

PubMed

Sako, M; Yaekura, I; Oda, S; Hirota, K

2000-10-06

[1-(15)N]-Labeled 4,6-dimethyl-4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide (1-(15)N1) was easily prepared by nitration of commercially available 6-amino-1,3-dimethyl-1H-pyrimidine-2,4-dione using 15N-enriched nitric acid followed by an intramolecular oxidative cyclization with iodosylbenzene diacetate under mild conditions. On the basis of the experimental results using 1-(15)N1, the formation of 8-phenyltheophylline (3), the 1,3-dimethylalloxazines (4: n = 0, 1), and 1,3,7,9-tetramethyl-1H,9H-pyrimido[5,4-g]pteridine-2,4,6,8-tetraone++ + (5) in the thermal reaction of the N-oxide 1 with benzylamine, aniline, or piperidine, and the generation of NO or NO-related species in the reaction with N-acetylcysteamine were reasonably explained by considering the initial attack of the employed nucleophiles on the 3a-position of 1.

Heteropentanuclear Oxalato-Bridged nd–4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

PubMed Central

Kuhn, Paul-Steffen; Cremer, Laura; Gavriluta, Anatolie; Jovanović, Katarina K; Filipović, Lana; Hummer, Alfred A; Büchel, Gabriel E; Dojčinović, Biljana P; Meier, Samuel M; Rompel, Annette; Radulović, Siniša; Tommasino, Jean Bernard; Luneau, Dominique; Arion, Vladimir B

2015-01-01

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d–4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by 13C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)]2− are coordinated to YIII and DyIII, respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4]5− (Ln=Y, Dy). While YIII is eight-coordinate in 2, DyIII is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N+ ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2–5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d–4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2–5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d–4f metal complexes 6–9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells. PMID:26260662

Highly Permeable AlPO-18 Membranes for N 2 /CH 4 Separation

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

Zong, Zhaowang; Elsaidi, Sameh K.; Thallapally, Praveen K.

Herein we demonstrate that AlPO-18 membranes can separate N2/CH4 gas mixtures at unprecedented N2 permeances. The best membranes separated N2/CH4 mixtures with N2 permeances as high as 3076 GPU and separation selectivities as high as 4.6. Gas mixture separation data, N2 and CH4 adsorption isotherms, ideal adsorbed solution theory (IAST), and breakthrough experiments were collected to understand the separation mechanisms. Competitive adsorption and differences in diffusivities were identified as the prevailing separation mechanisms. Differences in diffusivity played a more dominant role than the competitive adsorption, and led to nitrogen selective membranes.

40 CFR 721.10078 - Butanamide, 2-[(2-methoxy-4-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-, 4-[(17-substituted-3,6,9...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl)substituted...-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl)substituted...]-N-(2-methoxyphenyl)-3-oxo-, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl)substituted]phenyl...

Modular architecture of the T4 phage superfamily: A conserved core genome and a plastic periphery

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

Comeau, Andre M.; Bertrand, Claire; Letarov, Andrei

2007-06-05

Among the most numerous objects in the biosphere, phages show enormous diversity in morphology and genetic content. We have sequenced 7 T4-like phages and compared their genome architecture. All seven phages share a core genome with T4 that is interrupted by several hyperplastic regions (HPRs) where most of their divergence occurs. The core primarily includes homologues of essential T4 genes, such as the virion structure and DNA replication genes. In contrast, the HPRs contain mostly novel genes of unknown function and origin. A few of the HPR genes that can be assigned putative functions, such as a series of novelmore » Internal Proteins, are implicated in phage adaptation to the host. Thus, the T4-like genome appears to be partitioned into discrete segments that fulfil different functions and behave differently in evolution. Such partitioning may be critical for these large and complex phages to maintain their flexibility, while simultaneously allowing them to conserve their highly successful virion design and mode of replication.« less

40 CFR 721.1070 - Benzenamine, 4-methoxy-2-methyl-N-(3-methylphenyl).

Code of Federal Regulations, 2010 CFR

2010-07-01

... as benzenamine, 4-methoxy-2-methyl-N-(3-methylphenyl) (PMN P-01-152; CAS No. 93072-06-1) is subject... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenamine, 4-methoxy-2-methyl-N-(3... Specific Chemical Substances § 721.1070 Benzenamine, 4-methoxy-2-methyl-N-(3-methylphenyl). (a) Chemical...

Base-resolution detection of N 4-methylcytosine in genomic DNA using 4mC-Tet-assisted-bisulfite-sequencing

DOE PAGES

Yu, Miao; Ji, Lexiang; Neumann, Drexel A.; ...

2015-07-15

Restriction-modification (R-M) systems pose a major barrier to DNA transformation and genetic engineering of bacterial species. Systematic identification of DNA methylation in R-M systems, including N 6-methyladenine (6mA), 5-methylcytosine (5mC) and N 4-methylcytosine (4mC), will enable strategies to make these species genetically tractable. Although single-molecule, real time (SMRT) sequencing technology is capable of detecting 4mC directly for any bacterial species regardless of whether an assembled genome exists or not, it is not as scalable to profiling hundreds to thousands of samples compared with the commonly used next-generation sequencing technologies. Here, we present 4mC-Tet-assisted bisulfite-sequencing (4mC-TAB-seq), a next-generation sequencing method thatmore » rapidly and cost efficiently reveals the genome-wide locations of 4mC for bacterial species with an available assembled reference genome. In 4mC-TAB-seq, both cytosines and 5mCs are read out as thymines, whereas only 4mCs are read out as cytosines, revealing their specific positions throughout the genome. We applied 4mC-TAB-seq to study the methylation of a member of the hyperthermophilc genus, Caldicellulosiruptor, in which 4mC-related restriction is a major barrier to DNA transformation from other species. Lastly, in combination with MethylC-seq, both 4mC- and 5mC-containing motifs are identified which can assist in rapid and efficient genetic engineering of these bacteria in the future.« less

N-Heterocyclic Carbene Capture by Cytochrome P450 3A4

PubMed Central

Jennings, Gareth K.; Ritchie, Caroline M.; Shock, Lisa S.; Lyons, Charles E.

2016-01-01

Cytochrome P450 3A4 (CYP3A4) is the dominant P450 enzyme involved in human drug metabolism, and its inhibition may result in adverse interactions or, conversely, favorably reduce the systemic elimination rates of poorly bioavailable drugs. Herein we describe a spectroscopic investigation of the interaction of CYP3A4 with N-methylritonavir, an analog of ritonavir, widely used as a pharmacoenhancer. In contrast to ritonavir, the binding affinity of N-methylritonavir for CYP3A4 is pH-dependent. At pH <7.4, the spectra are definitively type I, whereas at pH ≥7.4 the spectra have split Soret bands, including a red-shifted component characteristic of a P450-carbene complex. Variable-pH UV-visible spectroscopy binding studies with molecular fragments narrows the source of this pH dependence to its N-methylthiazolium fragment. The C2 proton of this group is acidic, and variable-pH resonance Raman spectroscopy tentatively assigns it a pKa of 7.4. Hence, this fragment of N-methylritonavir is expected to be readily deprotonated under physiologic conditions to yield a thiazol-2-ylidene, which is an N-heterocyclic carbene that has high-affinity for and is presumed to be subsequently captured by the heme iron. This mechanism is supported by time-dependent density functional theory with an active site model that accurately reproduces distinguishing features of the experimental UV-visible spectra of N-methylritonavir bound to CYP3A4. Finally, density functional theory calculations support that this novel interaction is as strong as the tightest-binding azaheterocycles found in P450 inhibitors and could offer new avenues for inhibitor development. PMID:27126611

Highly Pathogenic Avian Influenza Virus (H5N8) Clade 2.3.4.4 Infection in Migratory Birds, Egypt.

PubMed

Selim, Abdullah A; Erfan, Ahmed M; Hagag, Naglaa; Zanaty, Ali; Samir, Abdel-Hafez; Samy, Mohamed; Abdelhalim, Ahmed; Arafa, Abdel-Satar A; Soliman, Mohamed A; Shaheen, Momtaz; Ibraheem, Essam M; Mahrous, Ibrahim; Hassan, Mohamed K; Naguib, Mahmoud M

2017-06-01

We isolated highly pathogenic avian influenza virus (H5N8) of clade 2.3.4.4 from the common coot (Fulica atra) in Egypt, documenting its introduction into Africa through migratory birds. This virus has a close genetic relationship with subtype H5N8 viruses circulating in Europe. Enhanced surveillance to detect newly emerging viruses is warranted.

47 CFR Figure 4 to Subpart N of... - Example of EPIRB Carrier Component

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Example of EPIRB Carrier Component 4 Figure 4 to Subpart N of Part 2 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY... Emergency Position Indicating Radiobeacons (EPIRBs) Pt. 2, Subpt. N, Fig. 4 Figure 4 to Subpart N of Part 2...

47 CFR Figure 4 to Subpart N of... - Example of EPIRB Carrier Component

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Example of EPIRB Carrier Component 4 Figure 4 to Subpart N of Part 2 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY... Emergency Position Indicating Radiobeacons (EPIRBs) Pt. 2, Subpt. N, Fig. 4 Figure 4 to Subpart N of Part 2...

Development of Sintered Si3N4 for High Performance Thermomechanical Applications.

DTIC Science & Technology

1984-01-01

noted( 17) that final grain size of sintered Si3 N4 is quite sensitive to both temperature and time at temperature. The sintering of Si NI containing...Characterization of Ube-SN-E0 Si3 N4 Chemical Analysis Lot A-10 Lot A-18 N (alkali fusion) wt . % 38 38 0 (inert gas fusion) wt . % 1.2 1.4 C (inert gas fusion) wt ...temperature stutral applications except for the high creep rate, Which is of the ame order a NC-13. The sintering of -qfiN4ontaning 5 wt % LiAIq0 1and

Biodegradation studies of N4-acetylsulfapyridine and N4-acetylsulfamethazine in environmental water by applying mass spectrometry techniques.

PubMed

García-Galán, María Jesús; Frömel, Tobias; Müller, Jutta; Peschka, Manuela; Knepper, Thomas; Díaz-Cruz, Silvia; Barceló, Damiá

2012-03-01

This work evaluates the biodegradation of N(4)-acetylsulfapyridine (AcSPY) and N(4)-acetylsulfamethazine (AcSMZ), metabolites of two of the most commonly used sulfonamides (SAs) in human and veterinary medicine, respectively. Aerobic transformation in effluent wastewater was simulated using aerated fixed-bed bioreactors. No visible changes in concentration were observed in the AcSMZ reactor after 90 days, whereas AcSPY was fully degraded after 32 days of experiment. It was also demonstrated that AcSPY transformed back to its parent compound sulfapyridine (SPY). The environmental presence of these two metabolites in wastewater effluent had been previously investigated and confirmed, together with three more SA acetylated metabolites and their corresponding parent compounds, in 18 different wastewater treatment plants in Hesse (Germany). Sulfamethoxazole (SMX) and SPY were the two SAs detected most frequently (90% and 89% of the samples, respectively) and in the highest concentrations (682 ng L(-1) for SMX and 532 ng L(-1) for SPY). To conclude, hazard quotients were calculated whenever toxicity data were available. None of the SAs studied posed an environmental risk.

N,N-dimethyl-2-(2-amino-4-(18)F-fluorophenylthio)-benzylamine (4-(18)F-ADAM): an improved PET radioligand for serotonin transporters.

PubMed

Shiue, Grace G; Choi, Seok-Rye; Fang, Ping; Hou, Catherine; Acton, Paul D; Cardi, Chris; Saffer, Janet R; Greenberg, Joel H; Karp, Joel S; Kung, Hank F; Shiue, Chyng-Yann

2003-12-01

There has been considerable interest in the development of PET radioligands that are useful for imaging serotonin transporter (SERT) in the living human brain. For the last decade, (11)C-(+)McN5652 has been the most promising PET agent for studying SERT in humans. However, this agent has some limitations. Recently, a new promising SERT PET radioligand, 3-(11)C-amino-4-(2-dimethylaminomethylphenylsulfanyl)benzonitrile, has been reported. We recently reported the synthesis of a new (18)F-labeled SERT PET radioligand, N,N-dimethyl-2-(2-amino-4-(18)F-fluorophenylthio)benzylamine (4-(18)F-ADAM), which may have advantages over (11)C-labeled radioligands. The purpose of this study was to evaluate this newly developed (18)F-labeled PET radioligand as a promising agent for studying SERT in the living human brain. This agent was evaluated by studying its in vitro binding to different monoamine transporters, its in vivo biodistributions in rats, its integrity and pharmacologic profiles in rat brain, and its distribution in a female baboon brain. In vitro binding assays showed that 4-F-ADAM displayed high affinity to SERT sites (inhibition constant = 0.081 nmol/L, using membrane preparations of LLC-PK1 cells expressing the specific transporter) and showed more than 1,000- and 28,000-fold selectivity for SERT over norepinephrine transporter and dopamine transporter, respectively. Biodistribution of 4-(18)F-ADAM in rats showed a high initial uptake and slow clearance in the brain (2.13%, 1.90%, and 0.95% injected dose per organ at 2, 30, and 60 min after intravenous injection, respectively), with the specific binding peaking at 2 h after injection (hypothalamus/cerebellum = 12.49). The uptake in blood, muscle, lung, kidney, and liver was also initially high but cleared rapidly. The radioactivity in the femur increases with time for 4-(18)F-ADAM, indicating that in vivo defluorination may occur. In vivo metabolism studies in rats showed that 4-(18)F-ADAM was not metabolized in

Three dimensional N=4 supersymmetric mechanics with Wu-Yang monopole

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

Bellucci, Stefano; Krivonos, Sergey; Sutulin, Anton

2010-05-15

We propose Lagrangian and Hamiltonian formulations of a N=4 supersymmetric three-dimensional isospin-carrying particle moving in the non-Abelian field of a Wu-Yang monopole and in some specific scalar potential. This additional potential is completely fixed by N=4 supersymmetry, and in the simplest case of flat metrics it coincides with that which provides the existence of the Runge-Lenz vector for the bosonic subsector. The isospin degrees of freedom are described on the Lagrangian level by bosonic auxiliary variables forming N=4 supermultiplet with additional, also auxiliary, fermions. Being quite general, the constructed systems include such interesting cases as N=4 superconformally invariant systems withmore » Wu-Yang monopole, the particles living in the flat R{sup 3} and in the RxS{sup 2} spaces and interacting with the monopole, and also the particles moving on three-dimensional sphere and pseudosphere with the Wu-Yang monopole sitting in the center. The superfield Lagrangian description of these systems is so simple that one could wonder to see how all couplings and the proper coefficients arise while passing to the component action.« less

Heteropentanuclear Oxalato-Bridged nd-4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity.

PubMed

Kuhn, Paul-Steffen; Cremer, Laura; Gavriluta, Anatolie; Jovanović, Katarina K; Filipović, Lana; Hummer, Alfred A; Büchel, Gabriel E; Dojčinović, Biljana P; Meier, Samuel M; Rompel, Annette; Radulović, Siniša; Tommasino, Jean Bernard; Luneau, Dominique; Arion, Vladimir B

2015-09-21

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d-4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by (13)C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)](2-) are coordinated to Y(III) and Dy(III), respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4](5-) (Ln=Y, Dy). While Y(III) is eight-coordinate in 2, Dy(III) is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N(+) ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2-5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d-4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2-5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d-4f metal complexes 6-9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open

Bis-Indole-Derived NR4A1 Ligands and Metformin Exhibit NR4A1-Dependent Glucose Metabolism and Uptake in C2C12 Cells.

PubMed

Mohankumar, Kumaravel; Lee, Jehoon; Wu, Chia Shan; Sun, Yuxiang; Safe, Stephen

2018-05-01

Treatment of C2C12 muscle cells with metformin or the NR4A1 ligand 1,1-bis(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) induced NR4A1 and Glut4 messenger RNA and protein expression. Similar results were observed with buttressed (3- or 3,5-substituted) analogs of DIM-C-pPhOH, including 1,1-bis(3'-indolyl)-1-(3-chloro-4-hydroxy-5-methoxyphenyl)methane (DIM-C-pPhOH-3-Cl-5-OCH3), and the buttressed analogs were more potent than DIM-C-pPhOH NR4A1 agonists. Metformin and the bis-indole substituted analogs also induced expression of several glycolytic genes and Rab4, which has previously been linked to enhancing cell membrane accumulation of Glut4 and overall glucose uptake in C2C12 cells, and these responses were also observed after treatment with metformin and the NR4A1 ligands. The role of NR4A1 in mediating the responses induced by the bis-indoles and metformin was determined by knockdown of NR4A1, and this resulted in attenuating the gene and protein expression and enhanced glucose uptake responses induced by these compounds. Our results demonstrate that the bis-indole-derived NR4A1 ligands represent a class of drugs that enhance glucose uptake in C2C12 muscle cells, and we also show that the effects of metformin in this cell line are NR4A1-dependent.

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine

NASA Astrophysics Data System (ADS)

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-01

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH = 3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreased gradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.7 × 107 L mol-1. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn.

N-(3-azidophenyl)-N-methyl-N'-([4-1H]- and [4-3H]-1-naphthyl)guanidine. A potent and selective ligand designed as a photoaffinity label for the phencyclidine site of the N-methyl-D-aspartate receptor.

PubMed

Gee, K R; Durant, G J; Holmes, D L; Magar, S S; Weber, E; Wong, S T; Keana, J F

1993-01-01

A novel radiolabeled photoaffinity ligand has been synthesized for the phencyclidine (PCP) site of the N-methyl-D-aspartate (NMDA) receptor. N-(3-Azidophenyl)-N-methyl-N'-([4-3H]-1-naphthyl)guanidine (13) was prepared with a specific activity of 25 Ci/mmol by diazotization of N-(3-aminophenyl)-N-methyl-N'-([4-3H]-1-naphthyl)guanidine (12) followed by treatment with sodium azide. Guanidine 12 was obtained by catalytic tritiation of N-(4-bromo-1-naphthyl)-N'-methyl-N'-(3-nitrophenyl)guanidine (11). The nontritiated analog 5 of 13 was prepared beginning with N-methyl-N'-1-naphthyl-N-(3-nitrophenyl)guanidine (9). The guanidines 9 and 11 were prepared in moderate yield by the aluminum chloride-catalyzed reaction of N-methyl-3-nitroaniline hydrochloride with 1-naphthylcyanamide and 4-bromo-1-naphthylcyanamide, respectively. Azide 5 showed high selectivity and affinity (IC50 = 100 nM vs [3H]MK801; 3000 nM vs [3H]ditolylguanidine) for the PCP site of the NMDA receptor in guinea pig brain homogenate. Photolabeling experiments with 13, however, failed to radiolabel a significant amount of receptor polypeptide.

A review on g-C3N4-based photocatalysts

NASA Astrophysics Data System (ADS)

Wen, Jiuqing; Xie, Jun; Chen, Xiaobo; Li, Xin

2017-01-01

As one of the most appealing and attractive technologies, heterogeneous photocatalysis has been utilized to directly harvest, convert and store renewable solar energy for producing sustainable and green solar fuels and a broad range of environmental applications. Due to their unique physicochemical, optical and electrical properties, a wide variety of g-C3N4-based photocatalysts have been designed to drive various reduction and oxidation reactions under light irradiation with suitable wavelengths. In this review, we have systematically summarized the photocatalytic fundamentals of g-C3N4-based photocatalysts, including fundamental mechanism of heterogeneous photocatalysis, advantages, challenges and the design considerations of g-C3N4-based photocatalysts. The versatile properties of g-C3N4-based photocatalysts are highlighted, including their crystal structural, surface phisicochemical, stability, optical, adsorption, electrochemical, photoelectrochemical and electronic properties. Various design strategies are also thoroughly reviewed, including band-gap engineering, defect control, dimensionality tuning, pore texture tailoring, surface sensitization, heterojunction construction, co-catalyst and nanocarbon loading. Many important applications are also addressed, such as photocatalytic water splitting (H2 evolution and overall water splitting), degradation of pollutants, carbon dioxide reduction, selective organic transformations and disinfection. Through reviewing the important state-of-the-art advances on this topic, it may provide new opportunities for designing and constructing highly effective g-C3N4-based photocatalysts for various applications in photocatalysis and other related fields, such as solar cell, photoelectrocatalysis, electrocatalysis, lithium battery, supercapacitor, fuel cell and separation and purification.

The Molybdenum(V) and Tungsten(VI) Oxoazides [MoO(N3 )3 ], [MoO(N3 )3 ⋅2 CH3 CN], [(bipy)MoO(N3 )3 ], [MoO(N3 )5 ](2-) , [WO(N3 )4 ], and [WO(N3 )4 ⋅CH3 CN].

PubMed

Haiges, Ralf; Skotnitzki, Juri; Fang, Zongtang; Dixon, David A; Christe, Karl O

2015-12-14

A series of novel molybdenum(V) and tungsten(VI) oxoazides was prepared starting from [MOF4 ] (M=Mo, W) and Me3 SiN3 . While [WO(N3 )4 ] was formed through fluoride-azide exchange in the reaction of Me3 SiN3 with WOF4 in SO2 solution, the reaction with MoOF4 resulted in a reduction of Mo(VI) to Mo(V) and formation of [MoO(N3 )3 ]. Carried out in acetonitrile solution, these reactions resulted in the isolation of the corresponding adducts [MoO(N3 )3 ⋅2 CH3 CN] and [WO(N3 )4 ⋅CH3 CN]. Subsequent reactions of [MoO(N3 )3 ] with 2,2'-bipyridine and [PPh4 ][N3 ] resulted in the formation and isolation of [(bipy)MoO(N3 )3 ] and [PPh4 ]2 [MoO(N3 )5 ], respectively. Most molybdenum(V) and tungsten(VI) oxoazides were fully characterized by their vibrational spectra, impact, friction and thermal sensitivity data and, in the case of [WO(N3 )4 ⋅CH3 CN], [(bipy)MoO(N3 )3 ], and [PPh4 ]2 [MoO(N3 )5 ], by their X-ray crystal structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The unique N-terminal zinc finger of synaptotagmin-like protein 4 reveals FYVE structure.

PubMed

Miyamoto, Kazuhide; Nakatani, Arisa; Saito, Kazuki

2017-12-01

Synaptotagmin-like protein 4 (Slp4), expressed in human platelets, is associated with dense granule release. Slp4 is comprised of the N-terminal zinc finger, Slp homology domain, and C2 domains. We synthesized a compact construct (the Slp4N peptide) corresponding to the Slp4 N-terminal zinc finger. Herein, we have determined the solution structure of the Slp4N peptide by nuclear magnetic resonance (NMR). Furthermore, experimental, chemical modification of Cys residues revealed that the Slp4N peptide binds two zinc atoms to mediate proper folding. NMR data showed that eight Cys residues coordinate zinc atoms in a cross-brace fashion. The Simple Modular Architecture Research Tool database predicted the structure of Slp4N as a RING finger. However, the actual structure of the Slp4N peptide adopts a unique C 4 C 4 -type FYVE fold and is distinct from a RING fold. To create an artificial RING finger (ARF) with specific ubiquitin-conjugating enzyme (E2)-binding capability, cross-brace structures with eight zinc-ligating residues are needed as the scaffold. The cross-brace structure of the Slp4N peptide could be utilized as the scaffold for the design of ARFs. © 2017 The Protein Society.

Novel N4-Like Bacteriophages of Pectobacterium atrosepticum.

PubMed

Buttimer, Colin; Hendrix, Hanne; Lucid, Alan; Neve, Horst; Noben, Jean-Paul; Franz, Charles; O'Mahony, Jim; Lavigne, Rob; Coffey, Aidan

2018-05-14

Pectobacterium atrosepticum is an economically important phytopathogen that is responsible for potato blackleg and soft rot, and for which current control strategies are limited. In this study, stem samples of potato crops exhibiting blackleg were taken from three farms in Co. Cork, Ireland, and they were found to be infected with P. atrosepticum . Three closely related bacteriophages (phages) that are specific to this phytopathogen were isolated and characterized, namely vB_PatP_CB1, vB_PatP_CB3, and vB_PatP_CB4 (abbreviated as CB1, CB3, and CB4). Both CB1 and CB3 were determined to infect 12 strains and CB4 10 strains of the 19 strains of P. atrosepticum tested. Morphology, latent periods, burst sizes, and their stability at various temperatures and pHs were also examined. Genome sequencing of the three phages revealed that they shared a minimum nucleotide identity of 93% with each other. Their genomes exhibited an Enquartavirinae genome organization, possessing several conserved proteins that were associated with phages of this group, like the type species Escherichia virus N4. Tandem electrospray ionization-mass spectrometry (ESI-MS/MS) allowed for the identification of ten structural proteins that form the virion of CB1, six that are conserved in phage N4. Biocontrol experiments demonstrated that the phages suppress soft rot formation upon co-inoculation with P. atrosepticum on whole tubers. The results of this study indicate that CB1 related phages could be good candidates for phage-based control.

Microbial CH4 and N2O Consumption in Acidic Wetlands

PubMed Central

Kolb, Steffen; Horn, Marcus A.

2012-01-01

Acidic wetlands are global sources of the atmospheric greenhouse gases methane (CH4), and nitrous oxide (N2O). Consumption of both atmospheric gases has been observed in various acidic wetlands, but information on the microbial mechanisms underlying these phenomena is scarce. A substantial amount of CH4 is consumed in sub soil by aerobic methanotrophs at anoxic–oxic interfaces (e.g., tissues of Sphagnum mosses, rhizosphere of vascular plant roots). Methylocystis-related species are likely candidates that are involved in the consumption of atmospheric CH4 in acidic wetlands. Oxygen availability regulates the activity of methanotrophs of acidic wetlands. Other parameters impacting on the methanotroph-mediated CH4 consumption have not been systematically evaluated. N2O is produced and consumed by microbial denitrification, thus rendering acidic wetlands as temporary sources or sinks for N2O. Denitrifier communities in such ecosystems are diverse, and largely uncultured and/or new, and environmental factors that control their consumption activity are unresolved. Analyses of the composition of N2O reductase genes in acidic wetlands suggest that acid-tolerant Proteobacteria have the potential to mediate N2O consumption in such soils. Thus, the fragmented current state of knowledge raises open questions concerning methanotrophs and denitrifiers that consume atmospheric CH4 and N2O in acidic wetlands. PMID:22403579

Incommensurate smectic order at the free surface in the nematic phase of 4-n-heptylphenyl-4'-(4''-nitrobenzoyloxy)benzoate (DB7NO2)

NASA Astrophysics Data System (ADS)

Ocko, B. M.; Pershan, P. S.; Safinya, C. R.; Chiang, L. Y.

1987-02-01

We report x-ray reflectivity measurements on the free surface of 4-n-heptylphenyl-4'-(4''-nitrobenzoyloxy)benzoate (DB7NO2) at the nematic to smectic-A phase transition, TNA=99.9 °C. The free surface in the nematic phase exhibits smecticlike ordering at two q vectors, one which is commensurate with the smectic-A monolayer q vector q2. The other q vector is incommensurate corresponding to ordering at ~0.59q2. The commensurate peak constructively interferes with the air-liquid interface while the incommensurate peak destructively interferes. These results are compared with bulk-phase x-ray scattering measurements.

Emissions of N2O from tropical forest soils - Response to fertilization with NH4(+), NO3(-), and PO4(3-)

NASA Technical Reports Server (NTRS)

Keller, M.; Kaplan, W. A.; Wofsy, S. C.; Da Costa, Jose Maria

1988-01-01

Undisturbed oxisols in a central Amazon tropical forest were fertilized with ammonium, nitrate, or phosphate. Enhanced emissions of N2O were observed for all treatments within one day of fertilization, with the response NO3(-) much greater than NH4(+) much greater than PO4(3-). Approximately, 0.5 percent of applied NO3(-) was converted to N2O within two weeks after application, with less than 0.1 percent of the NH4(+) converted to N2O. These experiments reveal a potentially large source of N2O from microbial reduction of NO3(-) in the clay soils of Amazonia.

The Heats of Formation of SiCl+n, for n=1-4

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Partridge, Harry; Arnold, James O. (Technical Monitor)

1997-01-01

The heats of formation of SiCl(sub n) and SiCl+(sub n), for n=1-4, have been determined using the G2(B3LYP/MP2/CC) approach. The results for the neutral systems are in very good agreement with previous work. High level calibration calculations show that ion results have about the same accuracy as the neutrals, and allow us to refine the G2(B3LYP/MP2/CC) values. The calculations show that the adiabatic IP of SiCl4 is about 7 kcal/mol smaller than the accepted value. Using a rigid rotor/harmonic oscillator approximation, the temperature dependence of the heat of formation, heat capacity, and entropy are computed for 300 to 4000 K and fit to a polynomial.

Proton-transfer lasers based on solid copolymers of modified 2-(2'-hydroxyphenyl)benzimidazoles with methacrylate monomers

NASA Astrophysics Data System (ADS)

Costela, A.; García-Moreno, I.; Mallavia, Ricardo; Amat-Guerri, F.; Barroso, J.; Sastre, R.

1998-06-01

We report on the lasing action of two newly synthesized 2-(2'-hydroxyphenyl) benzimidazole derivatives copolymerized with methyl methacrylate. The laser samples were transversely pumped with a N 2 laser at 337 nm. The influence on the proton-transfer laser performance of the distance between the chromophore group and the polymeric main chain and of the rigidity of the polymeric host matrix, were studied. Significant increases in lasing efficiency and photostability are demonstrated for some of the new materials, as compared to those previously obtained with related proton-transfer dyes also covalently bound to methacrylic monomers.

Fabrication of modified g-C3N4 nanorod/Ag3PO4 nanocomposites for solar-driven photocatalytic oxygen evolution from water splitting

NASA Astrophysics Data System (ADS)

Tian, Lin; Xian, Xiaozhai; Cui, Xingkai; Tang, Hua; Yang, Xiaofei

2018-02-01

Semiconductor-based photocatalysis has been considered as one of the most effective techniques to achieve the conversion of clean and sustainable sunlight to solar fuel, in which the construction of novel solar-driven photocatalytic systems is the key point. Here, we report initially the synthesis of modified graphitic carbon nitride (g-C3N4) nanorods via the calcination of intermediates obtained from the co-polymerization of precursors, and the in-situ hybridization of Ag3PO4 with as-prepared modified g-C3N4 to produce g-C3N4 nanorod/Ag3PO4 composite materials. The diameter of modified rod-like g-C3N4 materials is determined to be around 1 μm. Subsequently the morphological features, crystal and chemical structures of the assembled g-C3N4 nanorod/Ag3PO4 composites were systematically investigated by SEM, XRD, XPS, UV-vis diffuse reflectance spectra (DRS). Furthermore, the use of as-prepared composite materials as the catalyst for photocatalytic oxygen evolution from water splitting was studied. The oxygen-generating results showed that the composite photocatalyst modified with 600 mg rod-like g-C3N4 demonstrates 2.5 times higher efficiency than that of bulk Ag3PO4. The mechanism behind the enhancement in the oxygen-evolving activity is proposed on the basis of in-situ electron spin resonance (ESR) measurement as well as theoretical analysis. The study provides new insights into the design and development of new photocatalytic composite materials for energy and environmental applications.

Bimetallic-organic framework derived porous Co3O4/Fe3O4/C-loaded g-C3N4 nanocomposites as non-enzymic electrocatalysis oxidization toward ascorbic acid, dopamine acid, and uric acid

NASA Astrophysics Data System (ADS)

Hu, Bin; Liu, Yongkang; Wang, Zhuo-Wei; Song, Yingpan; Wang, Minghua; Zhang, Zhihong; Liu, Chun-Sen

2018-05-01

We report on the synthesis of Co- and Fe-based bimetallic nanocatalysts embedded in mesoporous carbon and g-C3N4 nanosheets (denoted as Co3O4/Fe3O4/mC@g-C3N4) for selectively simultaneous determination of ascorbic acid (AA), dopamine acid (DA), and uric acid (UA). These electrocatalysts consisting of bimetallic Co-Fe alloy nanoparticles encapsulated in N-doped carbon matrix were prepared via pyrolysis of Co/Fe-MOFs after grinding with high amounts of melamine. Chemical/crystal structures suggest high contents of mesoporous carbon in calcinated Co3O4/Fe3O4/mC nanocomposites, which exhibited enhanced electrocatalytic activity toward small biomolecules. The intrinsic performances of Co/Fe-MOFs with large specific surface area and regular nodes in the two-dimensional nanostructured g-C3N4 nanosheets endowed the as-prepared series of Co3O4/Fe3O4/mC@g-C3N4 nanocomposites with remarkable electrocatalytic activities and high adsorption ability toward oxidation of AA, DA, and UA. The developed biosensors also showed long-term stability and high selectivity for targeted analytes, with satisfactory results on actual samples in human urine. The results indicate that the as-synthesized Co3O4/Fe3O4/mC@g-C3N4 nanostructure exhibits good electrocatalytic activity and potential applications in clinical diagnosis and biosensing.

Formation mechanisms of Si3N4 and Si2N2O in silicon powder nitridation

NASA Astrophysics Data System (ADS)

Yao, Guisheng; Li, Yong; Jiang, Peng; Jin, Xiuming; Long, Menglong; Qin, Haixia; Kumar, R. Vasant

2017-04-01

Commercial silicon powders are nitrided at constant temperatures (1453 K; 1513 K; 1633 K; 1693 K). The X-ray diffraction results show that small amounts of Si3N4 and Si2N2O are formed as the nitridation products in the samples. Fibroid and short columnar Si3N4 are detected in the samples. The formation mechanisms of Si3N4 and Si2N2O are analyzed. During the initial stage of silicon powder nitridation, Si on the outside of sample captures slight amount of O2 in N2 atmosphere, forming a thin film of SiO2 on the surface which seals the residual silicon inside. And the oxygen partial pressure between the SiO2 film and free silicon is decreasing gradually, so passive oxidation transforms to active oxidation and metastable SiO(g) is produced. When the SiO(g) partial pressure is high enough, the SiO2 film will crack, and N2 is infiltrated into the central section of the sample through cracks, generating Si2N2O and short columnar Si3N4 in situ. At the same time, metastable SiO(g) reacts with N2 and form fibroid Si3N4. In the regions where the oxygen partial pressure is high, Si3N4 is oxidized into Si2N2O.

Endocrine-Disrupting Potential of Bisphenol A, Bisphenol A Dimethacrylate, 4-n-Nonylphenol, and 4-n-Octylphenol in Vitro: New Data and a Brief Review

PubMed Central

Bonefeld-Jørgensen, Eva C.; Long, Manhai; Hofmeister, Marlene V.; Vinggaard, Anne Marie

2007-01-01

Background An array of environmental compounds is known to possess endocrine disruption (ED) potentials. Bisphenol A (BPA) and bisphenol A dimethacrylate (BPA-DM) are monomers used to a high extent in the plastic industry and as dental sealants. Alkylphenols such as 4-n-nonylphenol (nNP) and 4-n-octylphenol (nOP) are widely used as surfactants. Objectives We investigated the effect in vitro of these four compounds on four key cell mechanisms including transactivation of a) the human estrogen receptor (ER), b) the human androgen receptor (AR), c) the aryl hydrocarbon receptor (AhR), and d) aromatase activity. Results All four compounds inhibited aromatase activity and were agonists and antagonists of ER and AR, respectively. nNP increased AhR activity concentration-dependently and further increased the 2,3,7,8-tetrachlorodibenzo-p-dioxin AhR action. nOP caused dual responses with a weak increased and a decreased AhR activity at lower (10−8 M) and higher concentrations (10−5–10−4 M), respectively. AhR activity was inhibited with BPA (10−5–10−4 M) and weakly increased with BPA-DM (10−5 M), respectively. nNP showed the highest relative potency (REP) compared with the respective controls in the ER, AhR, and aromatase assays, whereas similar REP was observed for the four chemicals in the AR assay. Conclusion Our in vitro data clearly indicate that the four industrial compounds have ED potentials and that the effects can be mediated via several cellular pathways, including the two sex steroid hormone receptors (ER and AR), aromatase activity converting testosterone to estrogen, and AhR; AhR is involved in syntheses of steroids and metabolism of steroids and xenobiotic compounds. PMID:18174953

Stimulation of dihydroxyacetone and glycerol kinase activity in Streptococcus faecalis by phosphoenolpyruvate-dependent phosphorylation catalyzed by enzyme I and HPr of the phosphotransferase systems

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

Deutscher, J.; Sauerwald, H.

1986-06-01

Recently a report was given of the phosphoenolpyruvate (PEP)-dependent phosphorylation of a 55-kilodalton protein of Streptococus faecalis catalyzed by enzyme I and histidine-containing protein (HPr) of the phosphotransferase system. The purified 55-kilodalton protein was found to exhibit dihydroxyacetone kinase activity. Glycerol was six times more slowly phosphorylated than dihydroxyacetone. The K/sub m/s were found to 0.7 mM for ATP, 0.45 mM for dihydroxyacetone, and 0.9 MM for glycerol. PEP-dependent phosphorylation of dihydroxyacetone kinase stimulated phosphorylation of both substrates about 10-fold. Fructose 1,6-diphosphate at concentrations higher than 2 mM inhibited the activity of phosphorylated and unphosphorylated dihydroxyacetone kinase in a noncompetitivemore » manner. The rate of PEP-dependent phosphorylation of dihydroxyacetone kinase was about 200-fold slower than the phosphorylation rate of III proteins (also called enzyme III or factor III), which so far have been considered the only phosphoryl acceptors of histidyl-phosphorylated HPr. P-Dihydroxyacetone kinase was found to be able to transfer its phosphoryl group in a backward reaction to HPr. Following (/sup 32/P)PEP-dependent phosphorylation and tryptic digestion of dihydroxyacetone kinase, the authors isolated a labeled peptide composed of 37 amino acids, as determined by amino acid analysis. The single histidyl residue of this peptide most likely carries the phosphoryl group in phosphorylated dihydroxyacetone kinase.« less

Quantitative interdependence of coeffectors, CcpA and cre in carbon catabolite regulation of Bacillus subtilis.

PubMed

Seidel, Gerald; Diel, Marco; Fuchsbauer, Norbert; Hillen, Wolfgang

2005-05-01

The phosphoproteins HPrSerP and CrhP are the main effectors for CcpA-mediated carbon catabolite regulation (CCR) in Bacillus subtilis. Complexes of CcpA with HPrSerP or CrhP regulate genes by binding to the catabolite responsive elements (cre). We present a quantitative analysis of HPrSerP and CrhP interaction with CcpA by surface plasmon resonance (SPR) revealing small and similar equilibrium constants of 4.8 +/- 0.4 microm for HPrSerP-CcpA and 19.1 +/- 2.5 microm for CrhP-CcpA complex dissociation. Forty millimolar fructose-1,6-bisphosphate (FBP) or glucose-6-phosphate (Glc6-P) increases the affinity of HPrSerP to CcpA at least twofold, but have no effect on CrhP-CcpA binding. Saturation of binding of CcpA to cre as studied by fluorescence and SPR is dependent on 50 microm of HPrSerP or > 200 microm CrhP. The rate constants of HPrSerP-CcpA-cre complex formation are k(a) = 3 +/- 1 x 10(6) m(-1).s(-1) and k(d) = 2.0 +/- 0.4 x 10(-3).s(-1), resulting in a K(D) of 0.6 +/- 0.3 nm. FBP and Glc6-P stimulate CcpA-HPrSerP but not CcpA-CrhP binding to cre. Maximal HPrSerP-CcpA-cre complex formation in the presence of 10 mm FBP requires about 10-fold less HPrSerP. These data suggest a specific role for FBP and Glc6-P in enhancing only HPrSerP-mediated CCR.

Conformational analysis of some N,N-diethyl-2-[(4‧-substituted) phenylthio] acetamides

NASA Astrophysics Data System (ADS)

Vinhato, Elisângela; Olivato, Paulo R.; Zukerman-Schpector, Julio; Dal Colle, Maurizio

2013-11-01

The conformational analysis of some N,N-diethyl-2[(4‧-substituted)phenylthio]acetamides bearing the substituents OMe 1, Me 2, H 3, Cl 4, Br 5 and NO26, was performed by νCO IR analysis, along with B3LYP/6-311++G(d,p) and Polarisable Continuum Model (PCM) calculations, as well as NBO analysis for 1, 3, and 6 and X-ray diffraction for 4. The results of the calculations indicated the existence of two stable conformation pairs, i.e. gauche (anti; syn) (most stable) and cis (anti; syn) in the gas phase. The gauche conformers were less polar with respect to the cis ones for 1 and 3, but more polar for 6. The most intense IR carbonyl doublet component observed at the lower frequency can be ascribed to the gauche conformers g(anti; syn) for 3-6 in n-C6H14, which is in agreement with the gauche and cis relative stabilities and frequencies resulting from the PCM calculations. Similarly, the single IR band for 1 and 2 in n-hexane may be attributed to the gauche conformers. The PCM calculations compared well with the IR data for the compounds in solution, showing that there is a progressive increase of the cis/gauche population ratio as the solvent polarity increases. The NBO analysis indicated that the gauche(anti; syn) conformation in the gas phase was stabilized by the relevant LPS4 → πC 2dbnd O 1∗, πC 2dbnd O 1 → σC 3sbnd S 4∗ , σC 3sbnd S 4 → πC 2dbnd O 1∗, πC 2dbnd O 1∗ → σC 3sbnd S 4∗, and LPO1 →σ∗ C11sbnd H28 orbital interactions, which were absent in the cis(anti; syn) conformer. On the contrary, the cis conformer for derivatives 1, 3, and 6 were stabilized by the σC 3 -S 4∗ →σ∗ C2sbnd N5 orbital interaction (through bond coupling), along with the additional LPO1 →σ∗ S4sbnd C10 interaction for 6. Moreover, the electrostatic repulsion between the Cδ+sbnd Sδ- and Cδ+dbnd Oδ- dipoles (Repulsive Field Effect) contributed to both the larger destabilization and increase of the νCO frequency of the cis conformer with respect

N-[2-(5-Bromo-2-morpholin-4-ylpyrim­idin-4-ylsulfan­yl)-4-meth­oxy­phen­yl]-2,4,6-trimethyl­benzene­sulfonamide

PubMed Central

Kumar, Mohan; Mallesha, L.; Sridhar, M. A.; Kapoor, Kamini; Gupta, Vivek K.; Kant, Rajni

2012-01-01

In the title compound, C24H27BrN4O4S2, the mol­ecule is twisted at the sulfonyl S atom with a C—S(O2)—N(H)—C torsion angle of 62.6 (3)°. The benzene rings bridged by the sulfonamide group are tilted to each other by a dihedral angle of 60.6 (1)°. The dihedral angle between the sulfur-bridged pyrimidine and benzene rings is 62.7 (1)°. The morpholine ring adopts a chair conformation. The mol­ecular conformation is stabilized by a weak intra­molecular π–π stacking inter­action between the pyrimidine and the 2,4,6-trimethyl­benzene rings [centroid–centroid distance = 3.793 (2) Å]. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds into a chain along the b axis. PMID:23284396

Experimental infection of highly pathogenic avian influenza viruses, Clade 2.3.4.4 H5N6 and H5N8, in Mandarin ducks from South Korea.

PubMed

Son, K; Kim, Y-K; Oem, J-K; Jheong, W-H; Sleeman, J M; Jeong, J

2018-06-01

Outbreaks of highly pathogenic avian influenza (HPAI) have been reported worldwide. Wild waterfowl play a major role in the maintenance and transmission of HPAI. Highly pathogenic avian influenza subtype H5N6 and H5N8 viruses simultaneously emerged in South Korea. In this study, the comparative pathogenicity and infectivity of Clade 2.3.4.4 Group B H5N8 and Group C H5N6 viruses were evaluated in Mandarin duck (Aix galericulata). None of the ducks infected with H5N6 or H5N8 viruses showed clinical signs or mortality. Serological assays revealed that the HA antigenicity of H5N8 and H5N6 viruses was similar to each other. Moreover, both the viruses did not replicate after cross-challenging with H5N8 and H5N6 viruses, respectively, as the second infection. Although both the viruses replicated in most of the internal organs of the ducks, viral replication and shedding through cloaca were higher in H5N8-infected ducks than in H5N6-infected ducks. The findings of this study provide preliminary information to help estimate the risks involved in further evolution and dissemination of Clade 2.3.4.4 HPAI viruses among wild birds. © 2017 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

Generalization of Faddeev-Popov rules in Yang-Mills theories: N = 3,4 BRST symmetries

NASA Astrophysics Data System (ADS)

Reshetnyak, Alexander

2018-01-01

The Faddeev-Popov rules for a local and Poincaré-covariant Lagrangian quantization of a gauge theory with gauge group are generalized to the case of an invariance of the respective quantum actions, S(N), with respect to N-parametric Abelian SUSY transformations with odd-valued parameters λp, p = 1,…,N and generators sp: spsq + sqsp = 0, for N = 3, 4, implying the substitution of an N-plet of ghost fields, Cp, instead of the parameter, ξ, of infinitesimal gauge transformations: ξ = Cpλ p. The total configuration spaces of fields for a quantum theory of the same classical model coincide in the N = 3 and N = 4 symmetric cases. The superspace of N = 3 SUSY irreducible representation includes, in addition to Yang-Mills fields 𝒜μ, (3 + 1) ghost odd-valued fields Cp, B̂ and 3 even-valued Bpq for p, q = 1, 2, 3. To construct the quantum action, S(3), by adding to the classical action, S0(𝒜), of an N = 3-exact gauge-fixing term (with gauge fermion), a gauge-fixing procedure requires (1 + 3 + 3 + 1) additional fields, Φ¯(3): antighost C¯, 3 even-valued Bp, 3 odd-valued B̂pq and Nakanishi-Lautrup B fields. The action of N = 3 transformations on new fields as N = 3-irreducible representation space is realized. These transformations are the N = 3 BRST symmetry transformations for the vacuum functional, Z3(0) =∫dΦ(3)dΦ¯(3)exp{(ı/ℏ)S(3)}. The space of all fields (Φ(3),Φ¯(3)) proves to be the space of an irreducible representation of the fields Φ(4) for N = 4-parametric SUSY transformations, which contains, in addition to 𝒜μ the (4 + 6 + 4 + 1) ghost-antighost, Cr = (Cp,C¯), even-valued, Brs = -Bsr = (Bpq,Bp4 = Bp), odd-valued B̂r = (B̂,B̂pq) and B fields. The quantum action is constructed by adding to S0(𝒜) an N = 4-exact gauge-fixing term with a gauge boson, F(4). The N = 4 SUSY transformations are by N = 4 BRST transformations for the vacuum functional, Z4(0) =∫dΦ(4)exp{(ı/ℏ)S(4)}. The procedures are valid for

Immobilization of Mn and NH4 (+)-N from electrolytic manganese residue waste.

PubMed

Chen, Hongliang; Liu, Renlong; Liu, Zuohua; Shu, Jiancheng; Tao, Changyuan

2016-06-01

The objective of this work was the immobilization of soluble manganese (Mn) and ammonium nitrogen (NH4 (+)-N) leached from electrolytic manganese residue (EMR). Immobilization of Mn was investigated via carbonation using carbon dioxide (CO2) and alkaline additives. NH4 (+)-N immobilization was evaluated via struvite precipitation using magnesium and phosphate sources. Results indicated that the immobilization efficiency of Mn using CO2 and quicklime (CaO) was higher than using CO2 and sodium hydroxide (NaOH). This higher efficiency was likely due to the slower release of OH(-) during CaO hydrolysis. The immobilization efficiency of Mn was >99.99 % at the CaO:EMR mass ratio of 0.05:1 for 20-min reaction time. The struvite precipitation of NH4 (+)-N was conducted in the carbonated EMR slurry and the immobilization efficiency was 89 % using MgCl2 · 6H2O + Na3PO4 · 12H2O at the Mg:P:N molar ratio of 1.5:1.5:1 for 90-min reaction time. A leaching test showed that the concentrations of Mn and NH4 (+)-N in the filtrate of the treated EMR were 0.2 and 9 mg/L, respectively. The combined immobilization of Mn and NH4 (+)-N was an effective pretreatment method in the harmless treatment of the EMR.

Electronic structure evolution and energy level alignment at C60/4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine]/MoOx/indium tin oxide interfaces

NASA Astrophysics Data System (ADS)

Liu, Xiaoliang; Yi, Shijuan; Wang, Chenggong; Wang, Congcong; Gao, Yongli

2014-04-01

The electronic structure evolution and energy level alignment have been investigated at interfaces comprising fullerene (C60)/4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine] (TAPC)/ molybdenum oxide (MoOx)/ indium tin oxide with ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy. With deposition of TAPC upon MoOx, a dipole of 1.58 eV was formed at the TAPC/MoOx interface due to electron transfer from TAPC to MoOx. The highest occupied molecular orbital (HOMO) onset of TAPC was pinned closed to the Fermi level, leading to a p-doped region and thus increasing the carrier concentration at the very interface. The downward band bending and the resulting built-in field in TAPC were favorable for the hole transfer toward the TAPC/MoOx interface. The rigid downward shift of energy levels of TAPC indicated no significant interface chemistry at the interface. With subsequent deposition of C60 on TAPC, a dipole of 0.27 eV was observed at the C60/TAPC heterojunction due to the electron transfer from TAPC to C60. This led to a drop of the HOMO of TAPC near the C60/TAPC interface, and hence further enhanced the band bending in TAPC. The band bending behavior was also observed in C60, similarly creating a built-in field in C60 film and improving the electron transfer away from the C60/TAPC interface. It can be deduced from the interface analysis that a promising maximum open circuit voltage of 1.5 eV is achievable in C60/TAPC-based organic photovoltaic cells.

Multisite constrained model of trans-4-(N,N-dimethylamino)-4'-nitrostilbene for structural elucidation of radiative and nonradiative excited states.

PubMed

Lin, Cheng-Kai; Wang, Yu-Fu; Cheng, Yuan-Chung; Yang, Jye-Shane

2013-04-18

A constrained model compound of trans-4-(N,N-dimethylamino)-4'-nitrostilbene (DNS), namely, compound DNS-B3 that is limited to torsions about the phenyl-nitro C-N bond and the central C═C bond, was prepared to investigate the structural nature of the radiative and nonradiative states of electronically excited DNS. The great similarities in solvent-dependent electronic spectra, fluorescence decay times, and quantum yields for fluorescence (Φf) and trans → cis photoisomerization (Φtc) between DNS and DNS-B3 indicate that the fluorescence is from a planar charge-transfer state and torsion of the nitro group is sufficient to account for the nonradiative decay of DNS. This conclusion is supported by TDDFT calculations on DNS-B3 in dichloromethane. The structure at the conical intersection for internal conversion is associated with not only a twisting but also a pyramidalization of the nitro group. The mechanism of the NO2 torsion is discussed in terms of the effects of solvent polarity, the substituents, and the volume demand. The differences and analogies of the NO2- vs amino-twisted intramolecular charge-transfer (TICT) state of trans-aminostilbenes are also discussed.

Structure determination of two structural analogs, named 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16F2N4S) and 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-chlorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C23H16ClFN4S) by synchrotron X-ray powder diffraction

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

Gündoğdu, Gülsüm; Aytaç, Sevim Peri; Müller, Melanie

Two novel compounds, 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-fluorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C 23H 16F 2N 4S) (1) and 3-[1-(2-fluoro-4-biphenyl)ethyl]-6-(4-chlorophenyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole (C 23H 16ClFN 4S) (2), have been designed and synthesized as cytotoxic agents. The compounds were characterized by infrared, proton nuclear magnetic resonance, mass spectral data, elemental analysis and X-ray powder diffraction. The present study comprises spectral data and crystal structures of these novel compounds determined from synchrotron X-ray powder diffraction data. The structure solutions were obtained by simulated annealing. The final structures were achieved by Rietveld refinement using soft restraints for all bond lengths, bond angles, and planar groups. Both compounds crystallize in space groupmore » $$P\\bar 1$$,Z= 2, with the unit-cell parametersa= 6.37433(9),b= 11.3641(2),c= 14.09115(19) Å,α= 80.1740(8)°,β= 85.1164(8)°,γ= 80.9831(10)°,V= 991.55(3) Å 3of compound (1) anda= 6.53736(6),b= 11.55725(15),c= 14.01373(13) Å,α= 80.3323(7)°,β= 84.8939(6)°,γ= 79.3954(8)°,V= 1024.08(2) Å 3of compound (2). Structural analyses reveal that the title compounds are isostructural.« less

$$ \\mathcal{N} $$ = 4 superconformal bootstrap of the K 3 CFT

DOE PAGES

Lin, Ying-Hsuan; Shao, Shu-Heng; Simmons-Duffin, David; ...

2017-05-23

We study two-dimensional (4; 4) superconformal eld theories of central charge c = 6, corresponding to nonlinear sigma models on K3 surfaces, using the superconformal bootstrap. This is made possible through a surprising relation between the BPS N = 4 superconformal blocks with c = 6 and bosonic Virasoro conformal blocks with c = 28, and an exact result on the moduli dependence of a certain integrated BPS 4-point function. Nontrivial bounds on the non-BPS spectrum in the K3 CFT are obtained as functions of the CFT moduli, that interpolate between the free orbifold points and singular CFT points. Wemore » observe directly from the CFT perspective the signature of a continuous spectrum above a gap at the singular moduli, and fi nd numerically an upper bound on this gap that is saturated by the A1 N = 4 cigar CFT. We also derive an analytic upper bound on the fi rst nonzero eigenvalue of the scalar Laplacian on K3 in the large volume regime, that depends on the K3 moduli data. As two byproducts, we find an exact equivalence between a class of BPS N = 2 superconformal blocks and Virasoro conformal blocks in two dimensions, and an upper bound on the four-point functions of operators of sufficiently low scaling dimension in three and four dimensional CFTs.« less

$$ \\mathcal{N} $$ = 4 superconformal bootstrap of the K 3 CFT

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

Lin, Ying-Hsuan; Shao, Shu-Heng; Simmons-Duffin, David

We study two-dimensional (4; 4) superconformal eld theories of central charge c = 6, corresponding to nonlinear sigma models on K3 surfaces, using the superconformal bootstrap. This is made possible through a surprising relation between the BPS N = 4 superconformal blocks with c = 6 and bosonic Virasoro conformal blocks with c = 28, and an exact result on the moduli dependence of a certain integrated BPS 4-point function. Nontrivial bounds on the non-BPS spectrum in the K3 CFT are obtained as functions of the CFT moduli, that interpolate between the free orbifold points and singular CFT points. Wemore » observe directly from the CFT perspective the signature of a continuous spectrum above a gap at the singular moduli, and fi nd numerically an upper bound on this gap that is saturated by the A1 N = 4 cigar CFT. We also derive an analytic upper bound on the fi rst nonzero eigenvalue of the scalar Laplacian on K3 in the large volume regime, that depends on the K3 moduli data. As two byproducts, we find an exact equivalence between a class of BPS N = 2 superconformal blocks and Virasoro conformal blocks in two dimensions, and an upper bound on the four-point functions of operators of sufficiently low scaling dimension in three and four dimensional CFTs.« less

Metastatic Neuroblastoma Confined to Distant Lymph Nodes (stage 4N) Predicts Outcome in Patients With Stage 4 Disease: A Study From the International Neuroblastoma Risk Group Database

PubMed Central

Morgenstern, Daniel A.; London, Wendy B.; Stephens, Derek; Volchenboum, Samuel L.; Hero, Barbara; Di Cataldo, Andrea; Nakagawara, Akira; Shimada, Hiroyuki; Ambros, Peter F.; Matthay, Katherine K.; Cohn, Susan L.; Pearson, Andrew D.J.; Irwin, Meredith S.

2014-01-01

Purpose The presence of distant metastases is one of the most powerful predictors of outcome in patients with neuroblastoma. However, the pattern of metastatic spread is not incorporated into current risk stratification systems. Small case series have suggested that patients with neuroblastoma who have metastatic disease limited to distant lymph nodes (4N disease) may have improved outcomes. Patients and Methods We analyzed retrospective data from the International Neuroblastoma Risk Group database for patients diagnosed from 1990 to 2002. 4N patients were compared with the remaining stage 4 patients (non-4N), excluding those with missing metastatic site data. Results In all, 2,250 International Neuroblastoma Staging System stage 4 patients with complete data were identified, of whom 146 (6.5%) had 4N disease. For 4N patients, event-free survival (EFS; 5-year, 77% ± 4%) and overall survival (OS; 5-year, 85% ± 3%) were significantly better than EFS (5-year, 35% ± 1%) and OS (5-year, 42% ± 1%) for non-4N stage 4 patients (P < .001). 4N patients were more likely to be younger (P < .001) and have tumors with favorable characteristics, including absence of MYCN amplification (89% v 69%; P < .001). In a multivariable analysis, 4N disease remained a significant predictor of outcome (hazard ratio for non-4N v 4N: 3.40 for EFS and 3.69 for OS). Within subgroups defined by age at diagnosis and tumor MYCN status, 4N disease was significantly associated with improved outcomes. Conclusion 4N represents a subgroup with better outcome than that of other patients with metastatic disease. These findings suggest that the biology and treatment response of 4N tumors differ from other stage 4 tumors, and less intensive therapy should be considered for this cohort. Future exploration of biologic factors determining the pattern of metastatic spread is warranted. PMID:24663047

N(4)-[B-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan)methyl]-2'-deoxycytidine as a potential boron delivery agent with respect to glioblastoma.

PubMed

Uram, Łukasz; Nizioł, Joanna; Maj, Piotr; Sobich, Justyna; Rode, Wojciech; Ruman, Tomasz

2017-11-01

Glioblastoma multiforme (GBM) is a central nervous system tumor of grade IV, according to the WHO classification, extremely resistant to all currently used forms of therapy, including resection, radiotherapy, chemotherapy or combined therapy. Therefore, more effective treatment strategies of this tumor are needed, with boron neutron capture therapy (BNCT) being a potential solution, provided a proper cancer cells-targeted 10B delivery agent is found. In search of such an agent, toxicity and capacity to target DNA of a boronated derivative of 2'-deoxycytidine, N(4)-[B-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan)methyl]-2'-deoxycytidine (1), was tested against human tumor vs. normal cells. The present in vitro results revealed 1 to show low toxicity for human U-118 MG glioma cells (in the mM range) and even by 3-4 - fold lower against normal human fibroblasts. In accord, induction of apoptosis dependent on caspase-3 and caspase-7 was detected at high (>20mM) concentration of 1. Although demonstrated to be susceptible to phosphorylation by human deoxycytidine kinase and to undergo incorporation in cellular DNA, the boron analogue did not disturb cell proliferation when applied at non-toxic concentrations and showed low toxicity to a model metazoan organism, Caenorhabditis elegans. Thus, N(4)-[B-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan)methyl]-2'-deoxycytidine appears a promising candidate for a 10B delivery agent to be used in BNCT, with C. elegans indicated as a good model for in vivo studies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4

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

Chen, Mingyang; Straatsma, Tjerk P.; Dixon, David A.

In the low energy structures of the (TiO 2) n(H 2O) m (n ≤ 4, m ≤ 2n) and (TiO 2) 8(H 2O) m (m = 3, 7, 8) clusters were predicted using a global geometry optimization approach, with a number of new lowest energy isomers being found. Water can molecularly or dissociatively adsorb on pure and hydrated TiO 2 clusters. Dissociative adsorption is the dominant reaction for the first two H 2O adsorption reactions for n = 1, 2, and 4, for the first three H 2O adsorption reactions for n = 3, and for the first four Hmore » 2O adsorption reactions for n = 8. As more H 2O’s are added to the hydrated (TiO 2)n cluster, dissociative adsorption becomes less exothermic as all the Ti centers become 4-coordinate. Furthermore two types of bonds can be formed between the molecularly adsorbed water and TiO 2 clusters: a Lewis acid–base Ti–O(H 2) bond or an O···H hydrogen bond. The coupled cluster CCSD(T) results show that at 0 K the H 2O adsorption energy at a 4-coordinate Ti center is ~15 kcal/mol for the Lewis acid–base molecular adsorption and ~7 kcal/mol for the H-bond molecular adsorption, in comparison to that of 8–10 kcal/mol for the dissociative adsorption. The cluster size and geometry independent dehydration reaction energy, ED, for the general reaction 2(-TiOH) → -TiOTi– + H 2O at 4-coordinate Ti centers was estimated from the aggregation reaction of nTi(OH) 4 to form the monocyclic ring cluster (TiO 3H 2) n + nH 2O. E D is estimated to be -8 kcal/mol, showing that intramolecular and intermolecular dehydration reactions are intrinsically thermodynamically allowed for the hydrated (TiO 2) n clusters with all of the Ti centers 4-coordinate, which can be hindered by cluster geometry changes caused by such processes. Finally by bending force constants for the TiOTi and OTiO bonds are determined to be 7.4 and 56.0 kcal/(mol·rad 2). Infrared vibrational spectra were calculated using density functional theory, and the new bands appearing upon water adsorption

Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4

DOE PAGES

Chen, Mingyang; Straatsma, Tjerk P.; Dixon, David A.

2015-10-20

In the low energy structures of the (TiO 2) n(H 2O) m (n ≤ 4, m ≤ 2n) and (TiO 2) 8(H 2O) m (m = 3, 7, 8) clusters were predicted using a global geometry optimization approach, with a number of new lowest energy isomers being found. Water can molecularly or dissociatively adsorb on pure and hydrated TiO 2 clusters. Dissociative adsorption is the dominant reaction for the first two H 2O adsorption reactions for n = 1, 2, and 4, for the first three H 2O adsorption reactions for n = 3, and for the first four Hmore » 2O adsorption reactions for n = 8. As more H 2O’s are added to the hydrated (TiO 2)n cluster, dissociative adsorption becomes less exothermic as all the Ti centers become 4-coordinate. Furthermore two types of bonds can be formed between the molecularly adsorbed water and TiO 2 clusters: a Lewis acid–base Ti–O(H 2) bond or an O···H hydrogen bond. The coupled cluster CCSD(T) results show that at 0 K the H 2O adsorption energy at a 4-coordinate Ti center is ~15 kcal/mol for the Lewis acid–base molecular adsorption and ~7 kcal/mol for the H-bond molecular adsorption, in comparison to that of 8–10 kcal/mol for the dissociative adsorption. The cluster size and geometry independent dehydration reaction energy, ED, for the general reaction 2(-TiOH) → -TiOTi– + H 2O at 4-coordinate Ti centers was estimated from the aggregation reaction of nTi(OH) 4 to form the monocyclic ring cluster (TiO 3H 2) n + nH 2O. E D is estimated to be -8 kcal/mol, showing that intramolecular and intermolecular dehydration reactions are intrinsically thermodynamically allowed for the hydrated (TiO 2) n clusters with all of the Ti centers 4-coordinate, which can be hindered by cluster geometry changes caused by such processes. Finally by bending force constants for the TiOTi and OTiO bonds are determined to be 7.4 and 56.0 kcal/(mol·rad 2). Infrared vibrational spectra were calculated using density functional theory, and the new bands appearing upon water adsorption

Nqrs Data for C24H76BLiN12O4P4 (Subst. No. 1593)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H76BLiN12O4P4 (Subst. No. 1593)

Characterization of 4-Nitrophenylpropyl-N-alkylamine Interactions with Sigma Receptors

PubMed Central

Chu, Uyen B.; Hajipour, Abdol R.; Ramachandran, Subramaniam; Ruoho, Arnold E.

2011-01-01

Sigma receptors are small membrane proteins implicated in a number of pathophysiological conditions including drug addiction, psychosis and cancer; thus, small molecule inhibitors of sigma receptors have been proposed as potential pharmacotherapeutics for these diseases. We previously discovered that endogenous monochain N-alkyl sphingolipids including D-erythro-sphingosine, sphinganine, and N,N-dimethyl sphingosine bind to the sigma-1 receptor at physiologically relevant concentrations [Ramachandran et al. 2009 Eur J Pharmacol. 609(1–3):19–26]. Here, we investigated several N-alkylamines of varying chain lengths as sigma receptor ligands. Although the KI values for N-alkylamines were found to be in the micromolar range, when N-3-phenylpropyl and N-3-(4-nitrophenyl)propyl derivatives of butyl- (1a and 1b), heptyl- (2a and 2b), dodecyl- (3a and 3b), and octadecyl-amine (4a and 4b) were evaluated as sigma receptor ligands we found that these compounds exhibited nanomolar affinities with both sigma-1 and sigma-2 receptors. A screen of the high affinity ligands 2a, 2b, 3a and 3b against a variety of other receptors/transporters confirmed these four compounds to be highly selective mixed sigma-1 and sigma-2 ligands. Additionally, in HEK293 cells reconstituted with Kv1.4 potassium channel and the sigma-1 receptor, these derivatives were able to inhibit the outward current from the channel – consistent with sigma receptor modulation. Finally, cytotoxicity assays showed that 2a, 2b, 3a and 3b were highly potent against a number of cancer cell lines, demonstrating their potential utility as mixed sigma-1 and sigma-2 receptor anti-cancer agents. PMID:21790129

An ingenious strategy of preparing TiO2/g-C3N4 heterojunction photocatalyst: In situ growth of TiO2 nanocrystals on g-C3N4 nanosheets via impregnation-calcination method

NASA Astrophysics Data System (ADS)

Zhang, Guanghui; Zhang, Tianyong; Li, Bin; Jiang, Shuang; Zhang, Xia; Hai, Li; Chen, Xingwei; Wu, Wubin

2018-03-01

An ingenious method was employed to design and fabricate the TiO2/g-C3N4 heterojunction photocatalysts in this study. The thermal oxidation etching of g-C3N4 nanosheets and the in situ growth of TiO2 nanocrystal on the surface of g-C3N4 nanosheets were completed simultaneously by the calcination process. The g-C3N4 nanosheets played a crucial role in regulating and assembling the structures and morphologies of TiO2. Furthermore, the thickness and content of g-C3N4, and the crystallinity of TiO2 in TiO2/g-C3N4 composites could be regulated and controlled by the calcination temperature. Among the resultant TiO2/g-C3N4 samples, the TiO2/g-C3N4 sample with 41.6 wt% g-C3N4 exhibited the highest photocatalytic activity. It could degrade almost all MO molecules under visible light irradiation within 3 h. Moreover, it displayed higher visible light photocatalytic performance for degrading MO solution than pure g-C3N4 and D-TiO2. The synergistic effect between TiO2 and g-C3N4 makes significant contributions to the enhancement of the visible light photocatalytic activity. In addition, the favorable photocatalytic performance of TiO2/g-C3N4 nanocomposites is also attributed to the porous structures and uniform morphologies, and large surface area. Furthermore, the resultant TiO2/g-C3N4 exhibits excellent photocatalytic stability. Radical trapping experiments indicated that rad O2- and h+ were the main reactive species during the photodegradation process under visible light irradiation. Hopefully, the results can offer new design and strategy for preparing other g-C3N4-based nanocomposites for environmental and energy applications.

Higher spin gauge theory on fuzzy \\boldsymbol {S^4_N}

NASA Astrophysics Data System (ADS)

Sperling, Marcus; Steinacker, Harold C.

2018-02-01

We examine in detail the higher spin fields which arise on the basic fuzzy sphere S^4N in the semi-classical limit. The space of functions can be identified with functions on classical S 4 taking values in a higher spin algebra associated to \

Synthesis, crystal structure and DFT studies of N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide

NASA Astrophysics Data System (ADS)

Gautam, P.; Gautam, D.; Chaudhary, R. P.

2013-12-01

The title compound N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide ( III) was obtained from the reaction of 2-(propan-2-ylidene)hydrazinecarbothioamide ( II) with acetic anhydride instead of formation of the desired thiosemcarbazide derivative of Meldrum acid. The structures of II and III were established by elemental analysis, IR, NMR, Mass and X-ray crystallographic studies. II crystallizes in triclinic system, sp. gr. Z = 2; III crystallizes in the monoclinic system, sp. gr. P21/ c, Z = 8. Density functional theory (DFT) calculations have been carried out for III. 1H and 13C NMR of III has been calculated and correlated with experimental results.

miR-7-1 POTENTIATED ESTROGEN RECEPTOR AGONISTS FOR FUNCTIONAL NEUROPROTECTION IN VSC4.1 MOTONEURONS

PubMed Central

CHAKRABARTI, M.; BANIK, N. L.; RAY, S. K.

2013-01-01

Protection of motoneurons is an important goal in the treatment of spinal cord injury (SCI). We tested whether neuroprotective microRNAs (miRs) like miR-206, miR-17, miR-21, miR-7-1, and miR-106a could enhance efficacy of estrogen receptor (ER) agonists such as 1,3,5-tris (4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT, ERα agonist), Way200070 (WAY, ERβ agonist), and estrogen (EST, ERα and ERβ agonist) in preventing apoptosis in the calcium ionophore (CI) insulted VSC4.1 motoneurons. We determined that 200 nM CI induced 70% cell death. Treatment with 50 nM PPT, 100 nM WAY, and 150 nM EST induced overexpression of ERα, ERβ, and both receptors, respectively, at mRNA and protein levels. Treatment with ER agonists significantly upregulated miR-206, miR-17, and miR-7-1 in the CI insulted VSC4.1 motoneurons. Transfection with miR-206, miR-17, or miR-7-1 mimic potentiated WAY or EST to inhibit apoptosis in the CI insulted VSC4.1 motoneurons. Overexpression of miR-7-1 maximally increased efficacy of WAY and EST for down regulation of pro-apoptotic Bax and upregulation of anti-apoptotic Bcl-2. A search using miRDB indicated that miR-7-1 could inhibit expression of L-type Ca2+ channel protein alpha 1C (CPα1C). miR-7-1 overexpression and WAY or EST treatment down regulated CPα1C but upregulated p-Akt to trigger cell survival signaling. The same therapeutic strategy increased expression of the Ca2+/calmodulin-dependent protein kinase II beta (CaMKIIβ) and the phosphorylated cAMP response element binding protein (p-CREB) so as to promote Bcl-2 transcription. Whole cell membrane potential and mitochondrial membrane potential studies indicated that miR-7-1 highly potentiated EST to preserve functionality in the CI insulted VSC4.1 motoneurons. In conclusion, our data indicated that miR-7-1 most significantly potentiated efficacy of EST for functional neuroprotection and this therapeutic strategy could be used in the future to attenuate apoptosis of motoneurons in SCI. PMID

MOF-Templated Fabrication of Hollow Co4N@N-Doped Carbon Porous Nanocages with Superior Catalytic Activity.

PubMed

Sheng, Jianping; Wang, Liqiang; Deng, Liu; Zhang, Min; He, Haichuan; Zeng, Ke; Tang, Feiying; Liu, You-Nian

2018-02-28

Metallic Co 4 N catalysts have been considered as one of the most promising non-noble materials for heterogeneous catalysis because of their high electrical conductivity, great magnetic property, and high intrinsic activity. However, the metastable properties seriously limit their applications for heterogeneous water phase catalysis. In this work, a novel Co-metal-organic framework (MOF)-derived hollow porous nanocages (PNCs) composed of metallic Co 4 N and N-doped carbon (NC) were synthesized for the first time. This hollow three-dimensional (3D) PNC catalyst was synthesized by taking advantage of Co-MOF as a precursor for fabricating 3D hollow Co 3 O 4 @C PNCs, along with the NH 3 treatment of Co-oxide frames to promote the in situ conversion of Co-MOF to Co 4 N@NC PNCs, benefiting from the high intrinsic activity and electron conductivity of the metallic Co 4 N phase and the good permeability of the hollow porous nanostructure as well as the efficient doping of N into the carbon layer. Besides, the covalent bridge between the active Co 4 N surface and PNC shells also provides facile pathways for electron and mass transport. The obtained Co 4 N@NC PNCs exhibit excellent catalytic activity and stability for 4-nitrophenol reduction in terms of low activation energy (E a = 23.53 kJ mol -1 ), high turnover frequency (52.01 × 10 20 molecule g -1 min -1 ), and high apparent rate constant (k app = 2.106 min -1 ). Furthermore, its magnetic property and stable configuration account for the excellent recyclability of the catalyst. It is hoped that our finding could pave the way for the construction of other hollow transition metal-based nitride@NC PNC catalysts for wide applications.

4-(Naphthalene-2-carboxamido)­pyridin-1-ium thio­cyanate–N-(pyridin-4-yl)naphthalene-2-carboxamide (1/1)

PubMed Central

Saeed, Sohail; Rashid, Naghmana; Butcher, Ray J.; Öztürk Yildirim, Sema; Hussain, Rizwan

2012-01-01

The asymmetric unit of the title compound, C16H13N2O+·NCS−·C16H12N2O, contains two N-(pyridin-4-yl)naphthalene-2-carboxamide mol­ecules, both are partially protonated in the pyridine moiety, i.e. the H atom attached to the pyridine N atom is partially occupied with an occupancy factor of 0.61 (3) and 0.39 (3), respectively. In the crystal, protonated and neutral N-(pyridin-4-yl)naphthalene-2-carboxamide mol­ecules are linked by N—H⋯N hydrogen bonding; the thio­cyanate counter-ion links with both protonated and neutral N-(pyridin-4-yl)naphthalene-2-carboxamide mol­ecules via N—H⋯S and N—H⋯N hydrogen bonding. The dihedral angles between the pyridine ring and naphthalene ring systems are 11.33 (6) and 9.51 (6)°, respectively. π–π stacking is observed in the crystal structure, the shortest centroid–centroid distance being 3.5929 (8) Å. The crystal structure was determined from a nonmerohedral twin {ratio of the twin components = 0.357 (1):0.643 (1) and twin law [-100 0-10 -101]}. PMID:23125774

Polybenzimidazoles via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

1995-01-01

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Exact partition functions for deformed N=2 theories with N_f=4 flavours

NASA Astrophysics Data System (ADS)

Beccaria, Matteo; Fachechi, Alberto; Macorini, Guido; Martina, Luigi

2016-12-01

We consider the Ω-deformed N=2 SU(2) gauge theory in four dimensions with N f = 4 massive fundamental hypermultiplets. The low energy effective action depends on the deformation parameters ɛ 1 , ɛ 2, the scalar field expectation value a, and the hypermultiplet masses m = ( m 1 , m 2 , m 3 , m 4). Motivated by recent findings in the N={2}^{*} theory, we explore the theories that are characterized by special fixed ratios ɛ 2 /ɛ 1 and m /ɛ 1 and propose a simple condition on the structure of the multi-instanton contributions to the prepotential determining the effective action. This condition determines a finite set Π N of special points such that the prepotential has N poles at fixed positions independent on the instanton number. In analogy with what happens in the N={2}^{*} gauge theory, the full prepotential of the Π N theories may be given in closed form as an explicit function of a and the modular parameter q appearing in special combinations of Eisenstein series and Jacobi theta functions with well defined modular properties. The resulting finite pole partition functions are related by AGT correspondence to special 4-point spherical conformal blocks of the Virasoro algebra. We examine in full details special cases where the closed expression of the block is known and confirms our Ansatz. We systematically study the special features of Zamolodchikov's recursion for the Π N conformal blocks. As a result, we provide a novel effective recursion relation that can be exactly solved and allows to prove the conjectured closed expressions analytically in the case of the Π1 and Π2 conformal blocks.

Highly Efficient and Simple Route to Synthesize N-(4-Acetylphenyl)-4-chlorobenzenesulfonamide and Its Crystal Structure

NASA Astrophysics Data System (ADS)

Kobkeatthawin, T.; Chantrapromma, S.; Chidan Kumar, C. S.; Fun, H.-K.

2017-12-01

The one-pot synthesis of N-(4-acetylphenyl)-4-chlorobenzenesulfonamide under base conditions is carried out. The present method offers several advantages such as excellent yields, short reaction times and high purity. The chemical structure was elucidated using 1H-NMR, FT-IR and UV-Vis spectroscopy. The crystal structure of the substance was determined by single crystal X-ray structure analysis. The molecule is in a V-shape. The two substituted benzene rings make the dihedral angle of 84.31(9)°. In the crystal packing, the molecules are linked by N-H···O and C-H···O hydrogen bonds into double chains along the b-axis. The crystal is further stabilized by weak C-H···O, C-Cl···π and π···π interactions.

Novel ternary g-C3N4/Ag3VO4/AgBr nanocomposites with excellent visible-light-driven photocatalytic performance for environmental applications

NASA Astrophysics Data System (ADS)

Barzegar, Javid; Habibi-Yangjeh, Aziz; Akhundi, Anise; Vadivel, S.

2018-04-01

Novel visible-light-induced photocatalysts were fabricated by integration of Ag3VO4 and AgBr semiconductors with graphitic carbon nitride (g-C3N4) through a facile refluxing method. The fabricated photocatalysts were extensively characterized by XRD, EDX, SEM, TEM, FT-IR, UV-vis DRS, BET, TGA, and PL instruments. The photocatalytic performance of these samples was studied by degradations of three dye contaminants under visible-light exposure. Among the ternary photocatalysts, the g-C3N4/Ag3VO4/AgBr (10%) nanocomposite displayed the maximum activity for RhB degradation with rate constant of 1366.6 × 10-4 min-1, which is 116, 7.23, and 38.5 times as high as those of the g-C3N4, g-C3N4/AgBr (10%), and g-C3N4/Ag3VO4 (30%) photocatalysts, respectively. The effects of synthesis time and calcination temperature were also investigated and discussed. Furthermore, according to the trapping experiments, it was found that superoxide anion radicals were the predominant reactive species in this system. Finally, the ternary photocatalyst displayed superlative activity in removal of the contaminants under visible-light exposure, displaying great potential of this ternary photocatalyst for environmental remediation, because of a facile synthesis route and outstanding photocatalytic performance.

Solid state coordination chemistry: structural consequences of variations in tether length in the oxovanadium-copper-bisterpy-[O3P(CH2)nPO3]4- system, n= 1-6 (bisterpy = 2,2':4',4'':2'',2'''-quarterpyridyl-6',6''-di-2-pyridine).

PubMed

Ouellette, Wayne; Koo, Bon-Kweon; Burkholder, Eric; Golub, Vladimir; O'Connor, C J; Zubieta, Jon

2004-05-21

Hydrothermal reactions of Na3VO4, an appropriate Cu(II) source, bisterpy and an organodiphosphonate, H2O3P(CH2)nPO3H2 (n = 1-6) yielded a family of materials of the type [Cu2(bisterpy)]4+/VxOy(n-)/[O3P(CH2)nPO3]4-. This family of bimetallic oxides is characterized by an unusual structural diversity. The oxides [[Cu2(bisterpy)]V2O4[O3PCH2PO3H]2] (1), [[Cu2(bisterpy)(H2O)]VO2[O3P(CH2)3PO3][HO3P(CH2)3PO3H2

Sequence and expression of the genes for HPr (ptsH) and enzyme I (ptsI) of the phosphoenolpyruvate-dependent phosphotransferase transport system from Streptococcus mutans.

PubMed Central

Boyd, D A; Cvitkovitch, D G; Hamilton, I R

1994-01-01

We report the sequencing of a 2,242-bp region of the Streptococcus mutants NG5 genome containing the genes for ptsH and ptsI, which encode HPr and enzyme I (EI), respectively, of the phosphoenolpyruvate-dependent phosphotransferase transport system. The sequence was obtained from two cloned overlapping genomic fragments; one expresses HPr and a truncated EI, while the other expresses a full-length EI in Escherichia coli, as determined by Western immunoblotting. The ptsI gene appeared to be expressed from a region located in the ptsH gene. The S. mutans NG5 pts operon does not appear to be linked to other phosphotransferase transport system proteins as has been found in other bacteria. A positive fermentation pattern on MacConkey-glucose plates by an E. coli ptsI mutant harboring the S. mutans NG5 ptsI gene on a plasmid indicated that the S. mutans NG5 EI can complement a defect in the E. coli gene. This was confirmed by protein phosphorylation experiments with 32P-labeled phosphoenolpyruvate indicating phosphotransfer from the S. mutans NG5 EI to the E. coli HPr. Two forms of the cloned EI, both truncated to varying degrees in the C-terminal region, were inefficiently phosphorylated and unable to complement fully the ptsI defect in the E. coli mutant. The deduced amino acid sequence of HPr shows a high degree of homology, particularly around the active site, to the same protein from other gram-positive bacteria, notably, S. salivarius, and to a lesser extent with those of gram-negative bacteria. The deduced amino acid sequence of S. mutans NG5 EI also shares several regions of homology with other sequenced EIs, notably, with the region around the active site, a region that contains the only conserved cystidyl residue among the various proteins and which may be involved in substrate binding. Images PMID:8132321

Amine templating effect absent in uranyl sulfates synthesized with 1,4-n-butyldiamine

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

Jouffret, Laurent J., E-mail: ljouffret@nd.edu; Wylie, Ernest M.; Burns, Peter C.

2013-01-15

Two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3), were synthesized and their crystal structures determined. NDUS2 was obtained in highly acidic media heat-treated at 373 K and subsequently maintained at 278 K until crystals formed after two months. NDUS3 results from the degradation of NDUS2 over the course of a few days. NDUS2 and NDUS3 crystallize in the monoclinic space group P2{sub 1}/n, a=10.9075(4) A, b=10.4513(4) A, c=17.7881(7) A, {beta}=97.908(2) Degree-Sign , V=2008.52(13) A{sup 3}, Z=4, at 140 K and a=8.8570(4) A,more » b=7.3299(3) A, c=20.4260(9) A, {beta}=95.140(2) Degree-Sign , V=1320.74(10) A{sup 3}, Z=4, at 140 K, respectively. The compounds contain interlayer 1,4-n-butyldiammonium cations that charge-balance the anionic structural units. - Graphical abstract: Amine templating effect absent in uranyl sulfates synthesized with 1,4-diaminobutane, as shown by the synthesis of two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3). Highlights: Black-Right-Pointing-Pointer Two layered uranyl sulfates were synthesized. Black-Right-Pointing-Pointer Amine molecules are located in the interlayers of the compounds. Black-Right-Pointing-Pointer No templating effect of the amine was observed. Black-Right-Pointing-Pointer Amine molecules are only charge balancing cations in the structures.« less

Solar photocatalytic water oxidation over Ag3PO4/g-C3N4 composite materials mediated by metallic Ag and graphene

NASA Astrophysics Data System (ADS)

Cui, Xingkai; Tian, Lin; Xian, Xiaozhai; Tang, Hua; Yang, Xiaofei

2018-02-01

Solar-driven water splitting over semiconductor-based photocatalysts provides direct conversion of solar energy to chemical energy, in which electron-hole separation and charge transport are critical for enhancing the photocatalytic activity of semiconducting materials. Moreover, the search for active photocatalysts that efficiently oxidize water remains a challenging task. Here, we demonstrate that a series of Ag3PO4/Ag/graphene/graphitic carbon nitride (g-C3N4) heterostructured materials can drive photocatalytic water oxidation efficiently under LED illumination. The water oxidation behavior of as-prepared composite photocatalysts in relation to the added amount of g-C3N4 and the roles of electron mediators was investigated in detail. Based on the illuminated Z-scheme photocatalytic mechanism, the photogenerated electrons and holes can be separated effectively and the electron-hole recombination of bulk material is suppressed. The reduced metallic Ag nanoparticles were found to function as the center for the accumulation of electrons from Ag3PO4 and holes from g-C3N4. By exploiting the proper addition of g-C3N4 into the composite, photocatalytic oxygen evolution performance over the heterostructured materials could be suitably tuned, which resulted in highly efficient water oxidation.

Barrier height modification and mechanism of carrier transport in Ni/in situ grown Si3N4/n-GaN Schottky contacts

NASA Astrophysics Data System (ADS)

Karpov, S. Y.; Zakheim, D. A.; Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Brunkov, P. N.; Lundina, E. Y.; Tsatsulnikov, A. F.

2018-02-01

In situ growth of an ultra-thin (up to 2.5 nm) Si3N4 film on the top of n-GaN is shown to reduce remarkably the height of the barrier formed by deposition of Ni-based Schottky contact. The reduction is interpreted in terms of polarization dipole induced at the Si3N4/n-GaN interface and Fermi level pinning at the Ni/Si3N4 interface. Detailed study of temperature-dependent current-voltage characteristics enables identification of the electron transport mechanism in such Schottky diodes under forward bias: thermal/field electron emission over the barrier formed in n-GaN followed by tunneling through the Si3N4 film. At reverse bias and room temperature, the charge transfer is likely controlled by Poole-Frenkel ionization of deep traps in n-GaN. Tunneling exponents at forward and reverse biases and the height of the Ni/Si3N4 Schottky barrier are evaluated experimentally and compared with theoretical predictions.

Decoration of mesoporous Co3O4 nanospheres assembled by monocrystal nanodots on g-C3N4 to construct Z-scheme system for improving photocatalytic performance

NASA Astrophysics Data System (ADS)

Wu, Haijun; Li, Chunmei; Che, Huinan; Hu, Hao; Hu, Wei; Liu, Chunbo; Ai, Junzhe; Dong, Hongjun

2018-05-01

The Co3O4/g-C3N4 Z-scheme system is constructed by decoration of mesoporous Co3O4 nanospheres assembled by monocrystal nanodots on the surface of g-C3N4, which dramatically improves the photocatalytic activity for degrading tetracycline hydrochloride (TC) compared with single g-C3N4. The microstructure investigations evidence the mesoporous structure and enlarged specific surface area of Co3O4/g-C3N4 Z-scheme system, which implies the increase of surface active sites and adsorption ability for reactant molecules. Moreover, by virtue of analyzing physical and photoelectrochemical properties, it evidences that the decoration effect of mesoporous Co3O4 nanospheres on the surface of g-C3N4 obviously improves the transfer and separation efficiency of charge carriers between two phase interfaces and broadens light harvest range. These important factors are beneficial to enhancing photocatalytic activity of Co3O4/g-C3N4 Z-scheme system. In addition, the photocatalityc reaction mechanism is also revealed in depth.

A facile one-pot preparation of Co3O4/g-C3N4 heterojunctions with excellent electrocatalytic activity for the detection of environmental phenolic hormones

NASA Astrophysics Data System (ADS)

Sun, Yanjuan; Jiang, Jizhou; Liu, Yi; Wu, Shengli; Zou, Jing

2018-02-01

The Co3O4/g-C3N4 heterojunctions were prepared by a facile one-pot thermal decomposition technique. Compared with g-C3N4, it was found that Co3O4/g-C3N4 heterojunctions possessed a higher Brunner-Emmet-Teller (BET) surface area, which was beneficial to the diffusion of aim molecules on the electrode surfaces. And the optimal Co3O4/g-C3N4 heterojunctions exhibited a narrower band gap and a higher donor density, resulting in an excellent electrocatalytic activity for environmental phenolic hormones. Moreover, the Co3O4/g-C3N4 heterojunctions were used for the electrochemical sensing of environmental phenolic hormones such as bisphenol A, pentachlorophenol, p-nitrophenol and octylphenol. All detection ranges reached three orders of magnitude, showing a lower limit of detection of 10-9 mol L-1. So, sensitivity and accurate determination of environmental phenolic hormones in real water samples may use this Co3O4/g-C3N4 heterojunctions modified electrode.

Formation of 4-ethoxy-4'-nitrosodiphenylamine in the reaction of the phenacetin metabolite 4-nitrosophenetol with glutathione.

PubMed

Klehr, H; Eyer, P; Schäfer, W

1987-08-01

Phenacetin, a constituent of several analgesic and antipyretic formulations has been made responsible for a variety of toxic and carcinogenic actions. 4-Nitrosophenetol, the N-oxydation product of intermediate 4-phenetidine, forms methemoglobin and binds covalently to sulfhydryl groups of proteins and glutathione. In the reaction of 4-nitrosophenetol with glutathione and other thiols an intermediate so-called "semimercaptal" is formed from which N-(thiol-S-yl)-4-phenetidine S-oxide, N-(thiol-S-yl)-4-phenetidine and 4-phenetidine derive. Besides thiol adducts, a yellow compound is formed which was isolated as a pure crystalline product (elemental analysis) and identified by FAB-MS, EI-MS, 13C-, 1H-NMR, and UV-VIS spectroscopy as 4-ethoxy-4'-nitrosodiphenylamine. This nitrosoarene is formed by an unknown mechanism from 4-nitrosophenetol and 4-phenetidine under liberation of ethanol. In human erythrocytes this compound is easily reduced to 4-amino-4'-ethoxydiphenylamine (FAB-MS, EI-MS, 13C-NMR). During the reaction of 4-nitrosophenetol with red cells only traces of 4-ethoxy-4'-nitrosodiphenylamine were formed, whereas up to 10% appeared as the reduction product 4-amino-4'-ethoxydiphenylamine. This latter compound is unstable in red cells and is metabolized further to unidentified products.

Multiferroic GaN nanofilms grown within Na-4 mica channels

NASA Astrophysics Data System (ADS)

Bhattacharya, Santanu; Datta, A.; Chakravorty, D.

2010-03-01

Gallium nitride nanofilms grown within nanochannels of Na-4 mica structure, exhibit ferromagnetism even at room temperature due to the presence of gallium vacancies at the surfaces of the nanofilms. These nanofilms also show a ferroelectric behavior at room temperature ascribed to a small distortion in the crystal structure of GaN due to its growth within the Na-4 mica nanochannels. A colossal increase in 338% in dielectric constant was observed for an applied magnetic field of 26 kOe. The magnetoelectric effect is ascribed to magnetostriction of magnetic GaN phase.

Ti n O2n-1-Coated Li4Ti5O12 Composite Anode Material for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Zhang, Xiaoyan; Xu, Wen; Liu, Wanying; Li, Xing; Zhong, Xiaoxi; Lin, Yuanhua

2018-01-01

In an effort to enhance the rate capability of Li4Ti5O12, the Ti n O2n-1-coated Li4Ti5O12 (Li4Ti5O12-Ti n O2n-1, 3 < n < 10) composite has been synthesized through a sol-gel process followed by heat treatment in H2 atmosphere. Compared with pure Li4Ti5O12, Li4Ti5O12-Ti n O2n-1 composite shows higher specific capacity, better rate capability and cycle stability. The initial discharge capacity of the Li4Ti5O12-Ti n O2n-1 composite electrode is 171.2 mAh g-1 at 0.2°C, and 103.8 mAh g-1 at 20°C. Moreover, the discharge capacity remains 79.5 mAh g-1 after 100 cycles at 20°C with a capacity loss of 23.4%. The improved rate capacity and cycling stability clarify the positive effects of Ti n O2n-1 coating layer in Li4Ti5O12-Ti n O2n-1 composite as an anode material for lithium ion batteries.

N-(3-Chloro-4-eth-oxy-1-methyl-1H-indazol-5-yl)-4-meth-oxy-benzene-sulfonamide.

PubMed

Chicha, Hakima; Rakib, El Mostapha; Hannioui, Abdellah; Saadi, Mohamed; El Ammari, Lahcen

2014-06-01

The indazole ring system of the title compound, C17H18ClN3O4S, is almost planar (r.m.s. deviation = 0.0113 Å) and forms dihedral angles of 32.22 (8) and 57.5 (3)° with the benzene ring and the mean plane through the 4-eth-oxy group, respectively. In the crystal, mol-ecules are connected by pairs of N-H⋯O hydrogen bonds into inversion dimers, which are further linked by π-π inter-actions between the diazole rings [inter-centroid distance = 3.4946 (11) Å], forming chains parallel to [101].

Reassortant clade 2.3.4.4 of highly pathogenic avian influenza A (H5N6) virus, Taiwan, 2017