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1.
Phys Rev E ; 103(6-1): 062131, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34271676

RESUMO

We simulate the two-dimensional XY model in the flow representation by a worm-type algorithm, up to linear system size L=4096, and study the geometric properties of the flow configurations. As the coupling strength K increases, we observe that the system undergoes a percolation transition K_{perc} from a disordered phase consisting of small clusters into an ordered phase containing a giant percolating cluster. Namely, in the low-temperature phase, there exhibits a long-ranged order regarding the flow connectivity, in contrast to the quasi-long-range order associated with spin properties. Near K_{perc}, the scaling behavior of geometric observables is well described by the standard finite-size scaling ansatz for a second-order phase transition. The estimated percolation threshold K_{perc}=1.1053(4) is close to but obviously smaller than the Berezinskii-Kosterlitz-Thouless (BKT) transition point K_{BKT}=1.1193(10), which is determined from the magnetic susceptibility and the superfluid density. Various interesting questions arise from these unconventional observations, and their solutions would shed light on a variety of classical and quantum systems of BKT phase transitions.

2.
Molecules ; 26(11)2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34199966

RESUMO

Nanfeng mandarins (Citrus reticulata Blanco cv. Kinokuni), Xunwu mandarins (Citrus reticulata Blanco), Yangshuo kumquats (Citrus japonica Thunb) and physiologically dropped navel oranges (Citrus sinensis Osbeck cv. Newhall) were used as materials to extract peel essential oils (EOs) via hydrodistillation. The chemical composition, and antibacterial and antioxidant activities of the EOs were investigated. GC-MS analysis showed that monoterpene hydrocarbons were the major components and limonene was the predominate compound for all citrus EOs. The antibacterial testing of EOs against five different bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) was carried out using the filter paper method and the broth microdilution method. Kumquat EO had the best inhibitory effect on B. subtilis, E. coli and S. typhimurium with MIC (minimum inhibitory concentration) values of 1.56, 1.56 and 6.25 µL/mL, respectively. All citrus EOs showed the antioxidant activity of scavenging DPPH and ABTS free radicals in a dose-dependent manner. Nanfeng mandarin EO presented the best antioxidant activity, with IC50 values of 15.20 mg/mL for the DPPH assay and 0.80 mg/mL for the ABTS assay. The results also showed that the antibacterial activities of EOs might not be related to their antioxidant activities.


Assuntos
Antibacterianos/química , Antioxidantes/química , Citrus/química , Óleos Voláteis/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Bacillus subtilis/efeitos dos fármacos , Citrus/classificação , Destilação , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Óleos Vegetais/química , Óleos Vegetais/isolamento & purificação , Óleos Vegetais/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Salmonella typhimurium/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
3.
Phys Rev Lett ; 126(18): 185302, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34018783

RESUMO

Vortices play a leading role in many fascinating quantum phenomena. Here we generate a large number of vortices by thermally quenching a fermionic superfluid of ^{6}Li atoms in an oblate optical trap and study their annihilation dynamics and spatial distribution. Over a wide interaction range from the attractive to the repulsive side across the Feshbach resonance, these quasi-two-dimensional vortices are observed to follow algebraic scaling laws both in time and space, having exponents consistent with the two-dimensional universality. We further simulate the classical XY model on the square lattice by a Glauber dynamics and find good agreement between the numerical and experimental behaviors. Our work provides a direct demonstration of the universal 2D vortex dynamics.

4.
Molecules ; 25(18)2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32916953

RESUMO

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the only natural vector of bacteria responsible for Huanglongbing (HLB), a worldwide destructive disease of citrus. ACP reproduces and develops only on the young leaves of its rutaceous host plants. Olfactory stimuli emitted by young leaves may play an important role in ACP control and HLB detection. In this study, volatile organic compounds (VOCs) from healthy and HLB-infected young leaves of navel orange and pomelo were analyzed by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). A total of 36 compounds (including dimers or polymers) were identified and quantified from orange and 10 from pomelo leaves. Some compounds showed significant differences in signal intensity between healthy and HLB-infected leaves and may constitute possible indicators for HLB infection. Principal component analysis (PCA) clearly discriminated healthy and HLB-infected leaves in both orange and pomelo. HS-GC-IMS was an effective method to identify VOCs from leaves. This study may help develop new methods for detection of HLB or find new attractants or repellents of ACP for prevention of HLB.


Assuntos
Citrus/química , Doenças das Plantas/microbiologia , Folhas de Planta/química , Compostos Orgânicos Voláteis/análise , Animais , Bactérias , Cromatografia Gasosa , Citrus/classificação , Frutas , Hemípteros , Espectrometria de Mobilidade Iônica , Análise de Componente Principal , Software
5.
Science ; 369(6503): 550-553, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32554628

RESUMO

Scalable, coherent many-body systems can enable the realization of previously unexplored quantum phases and have the potential to exponentially speed up information processing. Thermal fluctuations are negligible and quantum effects govern the behavior of such systems with extremely low temperature. We report the cooling of a quantum simulator with 10,000 atoms and mass production of high-fidelity entangled pairs. In a two-dimensional plane, we cool Mott insulator samples by immersing them into removable superfluid reservoirs, achieving an entropy per particle of [Formula: see text] The atoms are then rearranged into a two-dimensional lattice free of defects. We further demonstrate a two-qubit gate with a fidelity of 0.993 ± 0.001 for entangling 1250 atom pairs. Our results offer a setting for exploring low-energy many-body phases and may enable the creation of large-scale entanglement.

6.
Molecules ; 25(1)2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31948058

RESUMO

Grapefruit essential oil has been proven to have wide range of bioactivities. However, bioactivity of its molecular distillate has not been well studied. In this study, a light phase oil was obtained by molecular distillation from cold-pressed grapefruit essential oil and GC-MS was used to identify its chemical composition. The antimicrobial activity of the light phase oil was tested by filter paper diffusion method, and the anticancer activity was determined by the Cell Counting Kit-8 (CCK-8) assay. Twenty-four components were detected with a total relative content of 99.74%, including 97.48% of terpenes and 1.66% of oxygenated terpenes. The light phase oil had the best antimicrobial effect on Bacillus subtilis, followed by Escherichia coli, Staphylococcus aureus and Salmonellaty phimurium. DPPH and ABTS assays demonstrated that the light phase oil had good antioxidant activity. The CCK-8 assay of cell proliferation showed that the light phase oil had a good inhibitory effect on the proliferation of HepG2 liver cancer cells and HCT116 colon cancer cells.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Citrus paradisi/química , Destilação/métodos , Antibacterianos/efeitos adversos , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/efeitos adversos , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/efeitos adversos , Bacillus subtilis/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Células HCT116 , Células Hep G2 , Humanos , Testes de Sensibilidade Microbiana , Óleos Voláteis/efeitos adversos , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Extratos Vegetais/efeitos adversos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Óleos Vegetais/efeitos adversos , Óleos Vegetais/química , Óleos Vegetais/farmacologia , Staphylococcus aureus/efeitos dos fármacos
7.
Molecules ; 24(3)2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30704118

RESUMO

The essential oil of 'Gannanzao' orange peel was extracted by hydrodistillation, and the extraction conditions were optimized by Box⁻Behnken response surface methodology. The components of essential oil were analyzed by GC-MS. Thirty-nine different components were detected, accounting for 99.59% of the total oil. Limonene (88.07%) was the prominent component. The optimal extraction conditions were as follows: liquid material ratio of 8.4:1 (mL/g), sodium chloride concentration of 5.3%, and distillation time of 3.5 h. The Cell Counting Kit-8 assay showed that 'Gannanzao' orange peel essential oil had good dose-dependent inhibition effect on the proliferation of HepG2 hepatoma cells and HCT116 colorectal cancer cells. When the concentration of the essential oil was 0.6 µL/mL or higher, the viability rate of both cancer cells became lower than 13.0%. The transwell assay indicated the essential oil can inhibit migration of both cancer cells at the concentration of 0.3 µL/mL.


Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Citrus sinensis/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos Vegetais/química , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Células HCT116 , Células Hep G2 , Humanos , Extração Líquido-Líquido , Espectroscopia de Ressonância Magnética , Óleos Vegetais/farmacologia
8.
Pest Manag Sci ; 75(5): 1339-1345, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30367747

RESUMO

BACKGROUND: Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an important pest of citrus worldwide because it transmits the bacteria causing huanglongbing (HLB). We investigated the effects and persistence of two soil application rates of thiamethoxam on ACP populations in two flushing seasons in the field. Thiamethoxam and clothianidin residues in the fruit were detected to evaluate food safety. RESULTS: Soil application of 50% thiamethoxam water-dispersible granules at concentrations of 4 and 10 g tree-1 significantly decreased ACP populations, and there was a positive correlation between control efficacy and the persistence of thiamethoxam and clothianidin in leaves, providing longer-term protection for up to 90 days in the fall compared with 60 days in the spring. Higher thiamethoxam and clothianidin amounts were observed in new leaves than in old leaves. Thiamethoxam and clothianidin residues at a high rate in fruit were 0.012 and 0.010 mg kg-1 at harvest, respectively, and neither insecticides was detectable at low rates. CONCLUSIONS: These results demonstrate that soil-applied thiamethoxam plays a role in defending ACP, and provides an extended period of control efficacy. This knowledge could provide a reference for the control of ACP by soil application of thiamethoxam to reduce HLB spread. © 2018 Society of Chemical Industry.


Assuntos
Citrus/metabolismo , Hemípteros , Estações do Ano , Solo/química , Tiametoxam/metabolismo , Animais , Transporte Biológico , Citrus/microbiologia , Inocuidade dos Alimentos , Guanidinas/metabolismo , Hemípteros/fisiologia , Resistência a Inseticidas , Limite de Detecção , Modelos Lineares , Neonicotinoides/metabolismo , Resíduos de Praguicidas/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Tiazóis/metabolismo
9.
Food Sci Nutr ; 6(6): 1431-1437, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30258585

RESUMO

The present investigation reported the chemical composition of cold pressed Gannan navel orange peel essential oil (EO) and its molecular distillation fraction (light phase EO), and examined their antimicrobial activity against spoiling and pathogenic microorganisms. Gas chromatography-mass spectrometry analysis identified 27 and 20 different chemical constituents in cold pressed EO and light phase EO, respectively. Limonene was the major constituent, accounting for 85.32% of cold pressed EO and 60.44% of light phase EO. Both EOs and some of their constituents showed good antimicrobial activity. Compared to cold pressed EO, light phase EO exhibited the better antimicrobial activity under weak acidic and neutral conditions. The light phase EO presented a higher antimicrobial activity after thermo-treatment at 60-100°C for 20 min than cold pressed EO. These results demonstrated that light phase EO had a potential to be used as a novel antimicrobial agent for food preservation and food processing.

10.
Phys Rev Lett ; 120(16): 167202, 2018 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-29756936

RESUMO

We study the quantum spin dynamics of a frustrated XXZ model on a pyrochlore lattice by using large-scale quantum Monte Carlo simulation and stochastic analytic continuation. In the low-temperature quantum spin ice regime, we observe signatures of coherent photon and spinon excitations in the dynamic spin structure factor. As the temperature rises to the classical spin ice regime, the photon disappears from the dynamic spin structure factor, whereas the dynamics of the spinon remain coherent in a broad temperature window. Our results provide experimentally relevant, quantitative information for the ongoing pursuit of quantum spin ice materials.

11.
Molecules ; 22(8)2017 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-28829378

RESUMO

China is one of the leading producers of citrus in the world. Gannan in Jiangxi Province is the top navel orange producing area in China. In the present study, an essential oil was prepared by cold pressing of Gannan navel orange peel followed by molecular distillation. Its chemical composition was analyzed by GC-MS. Twenty four constituents were identified, representing 97.9% of the total oil. The predominant constituent was limonene (74.6%). The anticancer activities of this orange essential oil, as well as some of its major constituents, were investigated by MTT assay. This essential oil showed a positive effect on the inhibition of the proliferation of a human lung cancer cell line A549 and prostate cancer cell line 22RV-1. Some of the oil constituents displayed high anticancer potential and deserve further study.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/farmacologia , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Óleos Vegetais/farmacologia , Antineoplásicos Fitogênicos/química , Antioxidantes/química , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Sobrevivência Celular , Citrus sinensis/química , Cicloexenos/química , Cicloexenos/farmacologia , Frutas/química , Humanos , Limoneno , Óleos Voláteis/química , Extratos Vegetais/química , Óleos Vegetais/química , Terpenos/química , Terpenos/farmacologia
12.
J Econ Entomol ; 110(4): 1556-1562, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28444322

RESUMO

Sweet orange oil fractions were prepared by molecular distillation of cold-pressed orange oil from sample A (Citrus sinensis (L.) 'Hamlin' from America) and sample B (Citrus sinensis Osbeck 'Newhall' from China) respectively, and their fumigant activities against medium workers of red imported fire ants (Solenopsis invicta Buren) were investigated. The volatile composition of the orange oil fractions was identified and quantified using GC-MS. Fractions from sample A (A1, A2, and A3) contained 23, 37, and 48 chemical constituents, and fractions from sample B (B1, B2, and B3) contained 18, 29, and 26 chemical constituents, respectively. Monoterpenes were the most abundant components, accounting for 73.56% to 94.86% of total orange oil fractions, among which D-limonene (65.28-80.18%), ß-pinene (1.71-5.58%), 3-carene (0.41-4.01%), ß-phellandrene (0.58-2.10%), and linalool (0.31-2.20%) were major constituents. Fumigant bioassay indicated that all orange oil fractions exerted good fumigant toxicity against workers of fire ants at 3, 5, 10, and 20 mg/centrifuge tubes, and B1 had the strongest insecticidal potential, followed by A1, B2, A2, B3, and A3. The fractions composed of more high volatile molecules (A1 and B1) showed greater fumigant effects than others. Compounds linalool and D-limonene, which were the constituents of the orange oil, exhibited excellent fumigant toxicity against red imported fire ant workers. Linalool killed red imported fire ant workers completely at 5, 10, and 20 mg/tube after 8 h of treatment, and D-limonene induced >86% mortality at 8 h of exposure.


Assuntos
Formigas/efeitos dos fármacos , Citrus sinensis/química , Fumigação/métodos , Inseticidas/farmacologia , Óleos Voláteis/farmacologia , Animais , Óleos Vegetais/farmacologia , Especificidade da Espécie
13.
Am J Physiol Endocrinol Metab ; 312(4): E357-E367, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28270440

RESUMO

Liver X receptors, including LXRα and LXRß, are known to be master regulators of liver lipid metabolism. Activation of LXRα increases hepatic lipid storage in lipid droplets (LDs). 17ß-Hydroxysteroid dehydrogenase-13 (17ß-HSD13), a recently identified liver-specific LD-associated protein, has been reported to be involved in the development of nonalcoholic fatty liver disease. However, little is known about its transcriptional regulation. In the present study, we aimed at determining whether 17ß-HSD13 gene transcription is controlled by LXRs. We found that treatment with T0901317, a nonspecific LXR agonist, increased both 17ß-HSD13 mRNA and protein levels in cultured hepatocytes. It also significantly upregulated hepatic 17ß-HSD13 expression in wild-type (WT) and LXRß-/- mice but not in LXRα-/- mice. Basal expression of 17ß-HSD13 in the livers of LXRα-/- mice was lower than that in the livers of WT and LXRß-/- mice. Moreover, induction of hepatic 17ß-HSD13 expression by T0901317 was almost completely abolished in SREBP-1c-/- mice. Bioinformatics analysis revealed a consensus sterol regulatory element (SRE)-binding site in the promoter region of the 17ß-HSD13 gene. A 17ß-HSD13 gene promoter-driven luciferase reporter and ChIP assays further confirmed that the 17ß-HSD13 gene was under direct control of SREBP-1c. Collectively, these findings demonstrate that LXRα activation induces 17ß-HSD13 expression in a SREBP-1c-dependent manner. 17ß-HSD13 may be involved in the development of LXRα-mediated fatty liver.


Assuntos
17-Hidroxiesteroide Desidrogenases/metabolismo , Hepatócitos/metabolismo , Receptores X do Fígado/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , 17-Hidroxiesteroide Desidrogenases/genética , Animais , Regulação da Expressão Gênica , Hepatócitos/efeitos dos fármacos , Hidrocarbonetos Fluorados/farmacologia , Gotículas Lipídicas/metabolismo , Receptores X do Fígado/agonistas , Receptores X do Fígado/genética , Camundongos , Camundongos Knockout , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Sulfonamidas/farmacologia , Ativação Transcricional
14.
J Mol Cell Biol ; 8(6): 518-529, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27436752

RESUMO

Among the four prostaglandin E2 receptors, EP3 receptor is the one most abundantly expressed in white adipose tissue (WAT). The mouse EP3 gene gives rise to three isoforms, namely EP3α, EP3ß, and EP3γ, which differ only at their C-terminal tails. To date, functions of EP3 receptor and its isoforms in WAT remain incompletely characterized. In this study, we found that the expression of all EP3 isoforms were downregulated in WAT of both db/db and high-fat diet-induced obese mice. Genetic ablation of three EP3 receptor isoforms (EP3-/- mice) or EP3α and EP3γ isoforms with EP3ß intact (EP3ß mice) led to an obese phenotype with increased food intake, decreased motor activity, reduced insulin sensitivity, and elevated serum triglycerides. Since the differentiation of preadipocytes and mouse embryonic fibroblasts to adipocytes was markedly facilitated by either pharmacological blockade or genetic deletion/inhibition of EP3 receptor via the cAMP/PKA/PPARγ pathway, increased adipogenesis may contribute to obesity in EP3-/- and EP3ß mice. Moreover, both EP3-/- and EP3ß mice had increased lipolysis in WAT mainly due to the activated cAMP/PKA/hormone-sensitive lipase pathway. Taken together, our findings suggest that EP3 receptor and its α and γ isoforms are involved in both adipogenesis and lipolysis and influence food intake, serum lipid levels, and insulin sensitivity.


Assuntos
Adipogenia , Tecido Adiposo Branco/metabolismo , Lipólise , Receptores de Prostaglandina E Subtipo EP3/metabolismo , Adipócitos/metabolismo , Adipócitos/patologia , Animais , Diferenciação Celular , Deleção de Genes , Inflamação/metabolismo , Inflamação/patologia , Resistência à Insulina , Lipoproteínas VLDL/metabolismo , Camundongos , Camundongos Obesos , Obesidade/metabolismo , Obesidade/patologia , Fenótipo , Isoformas de Proteínas/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais , Triglicerídeos/metabolismo
15.
Biochim Biophys Acta ; 1851(10): 1317-26, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26170200

RESUMO

Arachidonic acid (AA) metabolism plays an important role in vascular homeostasis. We reported that DNA hypomethylation of EPHX2 induced a pro-inflammatory response in vascular endothelial cells (ECs). However, the change in the whole AA metabolism by DNA methylation is still unknown. Using a metabolomic approach, we investigated the effect of DNA methylation on the balance of AA metabolism and the underlying mechanism. ECs were treated with a DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-AZA), and AA metabolic profiles were analyzed. Levels of prostaglandin D2 (PGD2) and thromboxane B2 (TXB2), metabolites in the cyclooxygenase (COX) pathway, were significantly increased by 5-AZA treatment in ECs resulting from the induction of PGD2 synthase (PTGDS) and thromboxane A synthase 1 (TBXAS1) expression by DNA hypomethylation. This phenomenon was also observed in liver and kidney cell lines, indicating a universal mechanism. Pathophysiologically, homocysteine, known to cause DNA demethylation, induced a similar pattern of the change of AA metabolism. Furthermore, 5-AZA activated ECs, as evidenced by the upregulation of adhesion molecules. Indomethacin, a COX inhibitor, reversed the effects of 5-AZA on the levels of PGD2 and TXB2, EC activation and monocyte adhesion. In vivo, the plasma levels of PGD2 and TXB2 and the expression of In vivo PTGDS and TBXAS1 as well as adhesion molecules were increased in the aorta of the mice injected with 5-AZA. In conclusion, using a metabolomic approach, our study uncovered that DNA demethylation increased AA metabolites PGD2 and TXB2 by upregulating the expression of the corresponding enzymes, which might contribute to the DNA hypomethylation-induced endothelial activation.


Assuntos
Ácidos Araquidônicos/metabolismo , Metilação de DNA/fisiologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Animais , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Metilação de DNA/efeitos dos fármacos , Decitabina , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/fisiologia , Células HEK293 , Células Endoteliais da Veia Umbilical Humana/citologia , Humanos , Oxirredutases Intramoleculares/biossíntese , Rim/citologia , Rim/enzimologia , Lipocalinas/biossíntese , Fígado/citologia , Fígado/enzimologia , Masculino , Metabolômica , Camundongos , Tromboxano-A Sintase/biossíntese
16.
J Insect Sci ; 142014.
Artigo em Inglês | MEDLINE | ID: mdl-25525106

RESUMO

In total, 29 compounds from sweet wormwood (Artemisia annua L.) oil were identified using gas chromatography-mass spectrometry. The five active components were D-camphor, linalool, cineole, α-terpineol, and L(-)-borneol. The effectiveness of A. annua oil, as well as d-camphor, linalool, cineole, α-terpineol, and L(-)-borneol, as fumigants, contact insecticides, and repellents, were tested on the red imported fire ant Solenopsis invicta Buren. The results indicated that A. annua oil has no significant topical toxicity; however, the spray contact test revealed that it has strong insecticidal activity and the inhibitory effect is stronger during closed exposure than during open exposure. In the fumigant test, cineole and D-camphor exhibited strong fumigant toxicity on minor and major S. invicta workers. They also caused 100% mortality at 5, 3, 2, and 1 mg/centrifuge tube but not at 0.5 mg/centrifuge tube. The mortality rates of linalool, α-terpineol, and L(-)-borneol exceeded 80% at 5, 3, and 2 mg/centrifuge tube. In the repellent test, cineole and d-camphor showed significant repellency at 100, 10, and 1 mg/kg. However, linalool, α-terpineol, and L(-)-borneol significantly facilitated digging at 10 and 1 mg/kg.


Assuntos
Formigas/efeitos dos fármacos , Artemisia annua/química , Cânfora/farmacologia , Cicloexanóis/farmacologia , Repelentes de Insetos/farmacologia , Monoterpenos/farmacologia , Óleos Voláteis/farmacologia , Animais , Cânfora/química , Cicloexanóis/química , Cromatografia Gasosa-Espectrometria de Massas , Repelentes de Insetos/química , Inseticidas/química , Inseticidas/isolamento & purificação , Inseticidas/farmacologia , Monoterpenos/química
20.
Bioorg Med Chem Lett ; 19(3): 922-5, 2009 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19097779

RESUMO

The stereoselective synthesis of novel photoreactive gamma-secretase inhibitors 2 and 3 has been achieved. Key steps of the strategy involve preparation of alpha-N-Boc-epoxide 8 and formation of lactone 14 in a practical and stereo-controlled fashion. Compounds 2 and 3 are potent gamma-secretase inhibitors and directly interact with presenilin-1, a catalytic subunit of gamma-secretase.


Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/metabolismo , Biotinilação , Cristalografia por Raios X/métodos , Dipeptídeos/química , Desenho de Fármacos , Compostos de Epóxi/química , Células HeLa , Humanos , Concentração Inibidora 50 , Lactonas/química , Modelos Químicos , Fotoquímica/métodos , Presenilina-1/química
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