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1.
Xiu‐feng Zhang Lei Chen Qian‐fan Yang Qian Li Xiao‐ran Sun Hong‐bo Chen Guang Yang Ya‐lin Tang 《Luminescence》2015,30(8):1176-1183
Complexation between the primary carrier of ligands in blood plasma, human serum transferrin (Tf), and a cyanine dye, 3,3′‐di(3‐sulfopropyl)‐4,5,4′,5′‐dibenzo‐9‐phenyl‐thiacarbocyanine‐triethylam monium salt (PTC) was investigated using fluorescence spectra, UV/Vis absorption spectra, synchronous fluorescence spectra, circular dichroism (CD) and molecular dynamic docking. The experimental results demonstrate that the formation of PTC–Tf complex is stabilized by van der Waal's interactions and hydrogen bonds, and the binding constants were found to be 8.55 × 106, 8.19 × 106 and 1.75 × 104 M?1. Moreover, fluorescence experiments prove that the operational mechanism for the fluorescence quenching is static quenching and non‐radiative energy transfer. Structural investigation of the PTC–Tf complexes via synchronous fluorescence spectra and CD showed that the structure of Tf became more stable with a major increase in the α‐helix content and increased polarity around the tryptophan residues after PTC binding. In addition, molecular modeling highlights the residues located in the N‐lobe, which retain high affinity for PTC. The mode of action of the PTC–Tf complex is illustrated by these results, and may provide an effective pathway for the transport and targeted delivery of antitumor agents. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
Six amylose‐2‐acetyl‐3,6‐bis(phenylcarbamate) (AAPC) samples ranging in weight‐average molar mass Mw from 1.8 × 104 g mol?1 to 1.1 × 106 g mol?1 have been prepared from enzymatically synthesized amylose samples. Static light scattering, small‐angle X‐ray scattering, sedimentation equilibrium, and viscosity measurements were made for the samples in 1,4‐dioxane (DIOX), 2‐ethoxyethanol (2EE), and 2‐butanone (MEK) all at 25°C to determine particle scattering functions, z‐average radii of gyration, intrinsic viscosities, as well as Mw. The data were analyzed in terms of the wormlike cylinder model mainly to yield the helix pitch per residue h and the Kuhn segment length λ?1, which corresponds to twice of the persistence length. The latter parameters (λ?1) in 2EE (11 nm) and MEK (12 nm) are quite smaller than those for amylose tris(phenylcarbamate) (ATPC) in the same solvent (16 nm in 2EE and 18 nm in MEK) whereas those for AAPC (21 nm) and ATPC (22 nm) in DIOX are essentially the same as each other. This indicates that the chain stiffness of AAPC is more strongly influenced by the solvents since the number of intramolecular H‐bonds of AAPC is more changeable than that for ATPC. © 2012 Wiley Periodicals, Inc. Biopolymers 97:1010–1017, 2012. 相似文献
3.
Germanium‐ and Silicon‐Substituted Donor–Acceptor Type Copolymers: Effect of the Bridging Heteroatom on Molecular Packing and Photovoltaic Device Performance
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Jong Soo Kim Zhuping Fei Sebastian Wood David T. James Myungsun Sim Kilwon Cho Martin J. Heeney Ji‐Seon Kim 《Liver Transplantation》2014,4(18)
The effects of heteroatom substitution from a silicon atom to a germanium atom in donor‐acceptor type low band gap copolymers, poly[(4,4′‐bis(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]silole)‐2,6‐diyl‐alt‐(2,1,3‐benzothiadiazole)‐4,7‐diyl] (PSiBTBT) and poly[(4,4′‐bis(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]germole)‐2,6‐diyl‐alt‐(2,1,3‐benzothiadiazole)‐4,7‐diyl] (PGeBTBT), are studied. The optoelectronic and charge transport properties of these polymers are investigated with a particular focus on their use for organic photovoltaic (OPV) devices in blends with phenyl‐C70‐butyric acid methyl ester (PC70BM). It is found that the longer C‐Ge bond length, in comparison to C‐Si, modifies the molecular conformation and leads to a more planar chain conformation in PGeBTBT than PSiBTBT. This increase in molecular planarity leads to enhanced crystallinity and an increased preference for a face‐on backbone orientation, thus leading to higher charge carrier mobility in the diode configuration. These results provide important insight into the impact of the heavy atom substitution on the molecular packing and device performance of polymers based on the poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b]‐dithiophene)‐alt‐4,7‐(2,1,3‐benzothiadiazole) (PCPDTBT) backbone. 相似文献
4.
Balanced Carrier Mobilities: Not a Necessary Condition for High‐Efficiency Thin Organic Solar Cells as Determined by MIS‐CELIV
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Ardalan Armin Gytis Juska Mujeeb Ullah Marappan Velusamy Paul L. Burn Paul Meredith Almantas Pivrikas 《Liver Transplantation》2014,4(4)
A novel technique based upon injection‐charge extraction by linearly increasing voltage (i‐CELIV) in a metal‐insulator‐semiconductor (MIS) diode structure is described for studying charge transport in organic semiconductors. The technique (MIS‐CELIV) allows selective measurement of both electron and hole mobilities of organic solar cells with active layers thicknesses representative of operational devices. The method is used to study the model high efficiency bulk heterojunction combination poly[N‐9′′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] (PCDTBT) and [6,6]‐phenyl C70‐butyric acid methyl ester (PC70BM) at various blend ratios. The absence of bipolar transport in PCDTBT‐and‐PC70BM‐only diodes is shown and strongly imbalanced carrier mobility is found in the most efficient “optimized” blend ratios. The mobility measurements are correlated with overall device performance and it is found that balanced and high charge carrier mobility are not necessarily required for high efficiencies in thin film organic solar cells. 相似文献
5.
In this paper, a simple and novel method for the determination of polychlorinated biphenyls (PCBs), using silver nanoparticles (AgNPs) as a resonance light scattering (RLS) probe, is proposed. Under optimized conditions, there existed linear relationships between the enhancing RLS intensity of the system and the concentrations of PCBs in the range 8.0 × 10?8?1.0 × 10?6 g mL?1 for 2,4,4′‐trichlorbiphenyl (PCB28), 9.0 × 10?8?1.0 × 10?6 g mL?1 for 2,2′,5,5′‐tetrachlorbiphenyl (PCB52) and 4.0 × 10?8?1.0 × 10?6 g mL?1 for 3,3′,4,4′‐tetrachlorobiphenyl (PCB77). The corresponding detection limits (S/N = 3) were 2.6 × 10?8 g mL?1 for PCB28, 3.3 × 10?8 g mL?1 for PCB52 and 6.3 × 10?9 g mL?1 for PCB77, respectively. Finally, the mechanism of RLS enhancement was also studied. The results indicated that PCBs were adsorbed on the surface of AgNPs to form larger AgNP–PCB aggregates, resulting in the RLS enhancement of the system. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
6.
Zach M. Beiley Eric T. Hoke Rodrigo Noriega Javier Dacuña George F. Burkhard Jonathan A. Bartelt Alberto Salleo Michael F. Toney Michael D. McGehee 《Liver Transplantation》2011,1(5):954-962
Bulk heterojunction solar cells (BHJs) based on poly[N‐9″‐hepta‐decanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] (PCDTBT) can have internal quantum efficiencies approaching 100% but require active layers that are too thin to absorb more than ~70% of the above band gap light. When the active layer thickness is increased so that the cell absorbs more light, the fill factor and open circuit voltage decrease rapidly, so that the overall power conversion efficiency decreases. We find that hole‐traps in the polymer, which we characterize using space‐charge limited current measurements, play an important role in the performance of PCDTBT‐based BHJs and may limit the active layer thickness. Recombination due to carrier trapping is not often considered in BHJs because it is not believed to be a dominant loss mechanism in the “fruit‐fly” P3HT system. Furthermore, we show that in contrast to P3HT, PCDTBT has only weak short‐range molecular order, and that annealing at temperatures above the glass transition decreases the order in the π–π stacking. The decrease in structural order is matched by the movement of hole‐traps deeper into the band gap, so that thermal annealing worsens hole transport in the polymer and reduces the efficiency of PCDTBT‐based BHJs. These findings suggest that P3HT is not prototypical of the new class of high efficiency polymers, and that further improvement of BHJ efficiencies will necessitate the study of high efficiency polymers with low structural order. 相似文献
7.
Christine Knies Hans Reuter Katharina Hammerbacher Eugenia Bender Gabriel A. Bonaterra Ralf Kinscherf Helmut Rosemeyer 《化学与生物多样性》2019,16(3)
2‐Chloro‐2′‐deoxyadenosine (cladribine, 1 ) was acylated with valproic acid ( 2 ) under various reaction conditions yielding 2‐chloro‐2′‐deoxy‐3′,5′‐O‐divalproyladenosine ( 3 ) as well as the 3′‐O‐ and 5′‐O‐monovalproylated derivatives, 2‐chloro‐2′‐deoxy‐3′‐O‐valproyladenosine ( 4 ) and 2‐chloro‐2′‐deoxy‐5′‐O‐valproyladenosine ( 5 ), as new co‐drugs. In addition, 6‐azauridine‐2′,3′‐O‐(ethyl levulinate) ( 8 ) was valproylated at the 5′‐OH group (→ 9 ). All products were characterized by 1H‐ and 13C‐NMR spectroscopy and ESI mass spectrometry. The structure of the by‐product 6 (N‐cyclohexyl‐N‐(cyclohexylcarbamoyl)‐2‐propylpentanamide), formed upon valproylation of cladribine in the presence of N,N‐dimethylaminopyridine and dicyclohexylcarbodiimide, was analyzed by X‐ray crystallography. Cladribine as well as its valproylated co‐drugs were tested upon their cancerostatic/cancerotoxic activity in human astrocytoma/oligodendroglioma GOS‐3 cells, in rat malignant neuro ectodermal BT4Ca cells, as well as in phorbol‐12‐myristate 13‐acetate (PMA)‐differentiated human THP‐1 macrophages. The most important result of these experiments is the finding that only the 3′‐O‐valproylated derivative 4 exhibits a significant antitumor activity while the 5′‐O‐ as well as the 3′,5′‐O‐divalproylated cladribine derivatives 3 and 5 proved to be inactive. 相似文献
8.
Joseph P. Ramos Balaji Babu Sameer Chavda Yang Liu Adam Plaunt Amanda Ferguson Mia Savagian Megan Lee Samuel Tzou Shicai Lin Konstantinos Kiakos Shuo Wang Moses Lee John A. Hartley W. David Wilson 《Biopolymers》2013,99(8):497-507
Synthetic N‐methyl imidazole and N‐pyrrole containing polyamides (PAs) that can form “stacked” dimers can be programmed to target and bind to specific DNA sequences and control gene expression. To accomplish this goal, the development of PAs with lower molecular mass which allows for the molecules to rapidly penetrate cells and localize in the nucleus, along with increased water solubility, while maintaining DNA binding sequence specificity and high binding affinity is key. To meet these challenges, six novel f‐ImPy*Im PA derivatives that contain different orthogonally positioned moieties were designed to target 5′‐ACGCGT‐3′. The synthesis and biophysical characterization of six f‐ImPy*Im were determined by CD, ΔTM, DNase I footprinting, SPR, and ITC studies, and were compared with those of their parent compound, f‐ImPyIm. The results gave evidence for the minor groove binding and selectivity of PAs 1 and 6 for the cognate sequence 5′‐ACGCGT‐3′, and with strong affinity, Keq = 2.8 × 108 M?1 and Keq = 6.2 × 107 M?1, respectively. The six novel PAs presented in this study demonstrated increased water solubility, while maintaining low molecular mass, sequence specificity, and binding affinity, addressing key issues in therapeutic development. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 497–507, 2013. 相似文献
9.
Christopher M. Bianchetti George C. Blouin Eduard Bitto John S. Olson George N. Phillips Jr. 《Proteins》2010,78(4):917-931
The protein from Arabidopsis thaliana gene locus At1g79260.1 is comprised of 166‐residues and is of previously unknown function. Initial structural studies by the Center for Eukaryotic Structural Genomics (CESG) suggested that this protein might bind heme, and consequently, the crystal structures of apo and heme‐bound forms were solved to near atomic resolution of 1.32 Å and 1.36 Å, respectively. The rate of hemin loss from the protein was measured to be 3.6 × 10?5 s?1, demonstrating that it binds heme specifically and with high affinity. The protein forms a compact 10‐stranded β‐barrel that is structurally similar to the lipocalins and fatty acid binding proteins (FABPs). One group of lipocalins, the nitrophorins (NP), are heme proteins involved in nitric oxide (NO) transport and show both sequence and structural similarity to the protein from At1g79260.1 and two human homologues, all of which contain a proximal histidine capable of coordinating a heme iron. Rapid‐mixing and laser photolysis techniques were used to determine the rate constants for carbon monoxide (CO) binding to the ferrous form of the protein (k′CO = 0.23 μM?1 s?1, kCO = 0.050 s?1) and NO binding to the ferric form (k′NO = 1.2 μM–1 s–1, kNO = 73 s?1). Based on both structural and functional similarity to the nitrophorins, we have named the protein nitrobindin and hypothesized that it plays a role in NO transport. However, one of the two human homologs of nitrobindin contains a THAP domain, implying a possible role in apoptosis. Proteins 2010. © 2009 Wiley‐Liss, Inc. 相似文献
10.
Extracts and phenolic compounds from Zuccagnia punctata as fungicide seed protectants for corn
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C. M. Jiménez M.A. Sgariglia J.R. Soberón M.A. Vattuone D.A. Sampietro 《The Annals of applied biology》2018,173(2):112-120
The ethanolic leaf extract (TZP) of Zuccagnia punctata, its ethereal fraction (Eet), 2′,4′‐dihydroxychalcone (DC), 2′,4′‐dihydroxy‐3′‐methoxychalcone (DMC) and 7‐hydroxy‐3′,4′‐dimethoxyflavone (HF) were evaluated as fungicide seed protectants on corn. Microdilution assays on a set of Fusarium strains showed minimum inhibitory concentrations (MICs) of 400–800 μg mL?1 (TZP), 50–100 μg mL?1 (Eet), 25–50 μg mL?1 (DC), 50–100 μg mL?1 (DMC) and 200–400 μg mL?1 (HF), with minimum fungicidal concentration (MFC)/MIC = 1. Suspensions of TZP, Eet, DC and DMC at MIC × 20 incorporated to the grains at rates of 1920, 240, 120 and 240 mg dry matter kg?1 of grain, respectively, increased the elongation of the primary roots (24–44%) and the number of seminal roots (44–50%). TZP also increased the number of secondary roots. HF was phytotoxic. Suspensions of TZP, Eet, DC and DMC suppressed the endogenous grain mycoflora at levels similar to those recorded for a thiram + carbendazim‐based fungicide. Grains treated with TZP (1920 mg kg?1), Eet (240 mg kg?1), DC (120 mg kg?1) and DMC (240 mg kg?1) stimulated the growth of the seedling root system both because of fungal suppression and hormetic effects in greenhouse curative and preventive assays against Fusarium verticillioides on a sand/soil substrate. Eet and its chalcones also reduced the severity of seedling blight more than the thiram + carbendazim‐based fungicide in preventive assays and led to the same disease severity observed for the fungicide treatment in the curative assays. Our results show that Eet and its chalcones not only were effective seed protectants against F. verticillioides and other seedborne fungi, but also improved the early performance of maize seedlings. 相似文献
11.
Three mononuclear CuII complexes, [CuCl(naph‐pa)] ( 1 ), [Cu(bipy)(naph‐pa)]Cl ( 2 ), and [Cu(naph‐pa)(phen)]Cl ( 3 ) ((naph‐pa)=Schiff base derived from the condensation of 2‐hydroxynaphthalene‐1‐carbaldehyde and 2‐picolylamine (=2‐(aminomethyl)pyridine), bipy=2,2′‐bypiridine, and phen=1,10‐phenanthroline) were synthesized and characterized. Complex 1 exhibits square‐planar geometry, and 2 and 3 exhibit square pyramidal geometry, where Schiff base and bipy/phen act as NNO and as NN donor ligands, respectively. CT (Calf thymus)‐DNA‐binding studies revealed that the complexes bind through intercalative mode and show good binding propensity (intrinsic binding constant Kb: 0.98×105, 2.22×105, and 2.67×105 M ?1 for 1 – 3 , resp.). The oxidative and hydrolytic DNA‐cleavage activity of these complexes has been studied by gel electrophoresis: all the complexes displayed chemical nuclease activity in the presence and absence of H2O2. From the kinetic experiments, hydrolytic DNA cleavage rate constants were determined as 2.48, 3.32, and 4.10 h?1 for 1 – 3 , respectively. It amounts to (0.68–1.14)×108‐fold rate enhancement compared to non‐catalyzed DNA cleavage, which is impressive. The complexes display binding and cleavage propensity to DNA in the order of 3 > 2 > 1 . 相似文献
12.
Aurélien Tournebize Pierre‐Olivier Bussière Pascal Wong‐Wah‐Chung Sandrine Thérias Agnès Rivaton Jean‐Luc Gardette Serge Beaupré Mario Leclerc 《Liver Transplantation》2013,3(4):478-487
This paper reports on the photochemical behavior upon exposure to UV‐visible light of a poly(2,7‐carbazole) derivative for use in high‐performance solar cells. Poly[N‐9′‐hepta‐decanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)] (PCDTBT) is one of a relatively large class of push‐pull carbazole‐based copolymers that have been synthesized to better harvest the solar spectrum. The 2,7‐carbazole building block of PCDTBT is also used with different electron‐accepting units in a large variety of low‐band‐gap polymers. The photochemical and morphological behavior of PCDTBT thin films is investigated from the molecular scale to the nanomechanical properties. The photo‐oxidation mechanism is shown to be governed by chain‐scission and cross‐linking reactions. It results in dramatic evolution of the morphology, roughness and stiffness of thin PCDTBT films. Based on the identification of several photoproducts formed along the macromolecular chains or released into the gas phase, the main pathways of PCDTBT photochemical evolution are discussed. These processes first involve the scission of the C–N bond between the carbazole group and the tertiary carbon atom bearing the alkyl side‐chain. Modifications of the chemical structure of PCDTBT, the evolution of its UV‐visible absorbance, and its nanomechanical properties initiated by light irradiation are shown to be closely related. 相似文献
13.
Combinatorial Synthesis of New Pyrimidine‐ and Purine‐β‐d‐Ribonucleoside Nucleolipids: Their Distribution Between Aqueous and Organic Phases and Their In Vitro Activity Against Human‐ and Rat Glioblastoma Cells In Vitro
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Katharina Hammerbacher Katharina Görtemaker Christine Knies Eugenia Bender Gabriel A. Bonaterra Helmut Rosemeyer Ralf Kinscherf 《化学与生物多样性》2018,15(9)
14.
Yang Wang Bin Liu Chang Woo Koh Xin Zhou Huiliang Sun Jianwei Yu Kun Yang Hang Wang Qiaogan Liao Han Young Woo Xugang Guo 《Liver Transplantation》2019,9(24)
A series of polycyclic aromatic hydrocarbons (PAHs) with extended π‐conjugated cores (from naphthalene, anthracene, pyrene, to perylene) are incorporated into nonfullerene acceptors for the first time. Four different fused‐ring electron acceptors (FREAs), i.e., DTN‐IC‐2Ph , DTA‐IC‐3Ph , DTP‐IC‐4Ph , and DTPy‐IC‐5Ph , are prepared via simple and facile synthetic procedures, yielding a remarkable platform to study the structure–property relationship for nonfullerene solar cells. With the PAH core being extended systematically, the gradually redshifted absorption with enhanced molar extinction coefficient (ε) is realized, the energy level of the highest occupied molecular orbital is up‐shifted, and the electron mobility is greatly enhanced. Meanwhile, the solubility decreases and the molecular packing becomes strengthened. As a result, with an optimized combination of these characteristics, DTP‐IC‐4Ph attains good solubility, high molar extinction coefficient, complementary absorption, suitable morphology, well‐matched energy levels, as well as efficient charge dissociation and transport in blend film. Consequently, the DTP‐IC‐4Ph ‐based solar cells with a donor polymer, poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T) exhibit a promising power conversion efficiency of 10.37% without any additives, which is close to the best performance achieved in additive‐free nonfullerene solar cells (NFSCs). The results demonstrate that the PAH building blocks have great potential for the construction of novel FREAs for efficient additive‐free NFSCs. 相似文献
15.
Synthesis and Deprotection of Biodegradably and Thermally Protected Dinucleoside‐2′,5′‐Monophosphate Prodrug Model of 2‐5A
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Protected dinucleoside‐2′,5′‐monophosphate has been prepared to develop a prodrug strategy for 2‐5A. The removal of enzymatically and thermally labile 4‐(acetylthio)‐2‐(ethoxycarbonyl)‐3‐oxo‐2‐methylbutyl phosphate protecting group and enzymatically labile 3′‐O‐pivaloyloxymethyl group was followed at pH 7.5 and 37 °C by HPLC from the fully protected dimeric adenosine‐2′,5′‐monophosphate 1 used as a model compound for 2‐5A. The desired unprotected 2′,3′‐O‐isopropylideneadenosine‐2′,5′‐monophosphate ( 9 ) was observed to accumulate as a major product. Neither the competitive isomerization of 2′,5′‐ to a 3′,5′‐linkage nor the P–O5′ bond cleavage was detected. The phosphate protecting group was removed faster than the 3′‐O‐protection and, hence, the attack of the neighbouring 3′‐OH on phosphotriester moiety did not take place. 相似文献
16.
The Introduction of Fluorine and Sulfur Atoms into Benzotriazole‐Based p‐Type Polymers to Match with a Benzotriazole‐Containing n‐Type Small Molecule: “The Same‐Acceptor‐Strategy” to Realize High Open‐Circuit Voltage
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“The Same‐Acceptor‐Strategy” (SAS) adopts benzotriazole (BTA)‐based p‐type polymers paired with a new BTA based non‐fullerene acceptor BTA13 to minimize the trade‐off between the open‐circuit voltage (VOC) and short circuit current (JSC). The fluorination and sulfuration are introduced to lower the highest occupied molecular orbitals (HOMO) of the polymers. The fluorinated polymer of J52‐F shows the higher power conversion efficiency (PCE) of 8.36% than the analog polymer of J52, benefited from a good balance between an improved VOC of 1.18 V and a JSC of 11.55 mA cm?2. Further adding alkylthio groups on J52‐F, the resulted polymer, J52‐FS, exhibits the highest VOC of 1.24 V with a decreased energy loss of 0.48 eV, compared with 0.67 eV for J52 and 0.54 eV for J52‐F. However, J52‐FS shows an inferior PCE (3.84%) with a lower JSC of 6.74 mA cm?2, because the small ΔEHOMO between J52‐FS and BTA13 (0.02 eV) gives rise to the inefficient hole transfer and high charge recombination, as well as low carrier mobilities. The results of this study clearly demonstrate that the introduction of different atoms in p‐type polymers is effective to improve the SAS and realize the high (VOC) and PCE. 相似文献
17.
Dehalogenation Activity of Selected Fungi Toward δ‐Iodo‐γ‐Lactone Derived from trans,trans‐Farnesol
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Anna Gliszczyńska Witold Gładkowski Marta Świtalska Joanna Wietrzyk Antoni Szumny Elżbieta Gębarowska Czesław Wawrzeńczyk 《化学与生物多样性》2016,13(4):477-482
Time‐course of biotransformation of racemic trans‐4‐((E)‐4′,8′‐dimethylnona‐3′,7′‐dien‐1‐yl)‐5‐iodomethyl‐4‐methyldihydrofuran‐2‐one ( 1 ) in fungal and yeast cultures was investigated. In these conditions, the substrate 1 was enantioselectively dehalogenated yielding 4‐((E)‐4′,8′‐dimethylnona‐3′,7′‐dien‐1‐yl)‐4‐methyl‐5‐methylenedihydrofuran‐2‐one ( 2 ) and its structure was established based on the spectroscopic data. The most effective biocatalyst used was Didymosphaeria igniaria, which catalyzed the process with highest rate and enantioselectivity (ee of product = 76%). The antiproliferative activity of δ‐iodo‐γ‐lactone 1 , product of its biotransformation 2 , and starting substrate (farnesol) were evaluated toward two cancer cell lines: A549 (human lung adenocarcinoma) and HL‐60 (human promyelocytic leukemia). 相似文献
18.
Muhammad Asghar Mohammad Yaqoob Masood Ahmed Siddiqui Nusrat Munawar Amir Waseem Abdul Nabi 《Luminescence》2020,35(1):79-89
Chemiluminescence (CL) of the rhodamine 6‐G‐diperiodatonickelate (IV) (Rh6‐G‐Ni(IV) complex) in the presence of Brij‐35 was examined in an alkaline medium and implemented using flow‐injection analysis to analyze Mn(II) in natural waters. Brij‐35 was identified as the surfactant of choice that enhanced CL intensity by about 62% of the reaction. The calibration curves were linear in the range 1.7 × 10?3 – 0.2 (0.9990, n = 7) and 8.0 × 10?4 – 0.1 μg ml?1 (0.9990, n = 7) with limits of detection (LODs) (S:N = 3) of 5.0 × 10?4 and 2.4 × 10?4 μg ml?1 without and with using an in‐line 8‐hydroxyquinoline (8‐HQ) resin mini‐column, respectively. The sample throughput and relative standard deviation were 200 h?1 and 1.7–2.2% in the range studied respectively. Mn(II) concentrations in certified reference materials and natural water samples was successfully determined. A brief discussion about the possible CL reaction mechanism is also given. In addition, analysis of V(III), Cr(III) and Fe(II) was also performed without and with using an in‐line 8–HQ column and selective elution of each metal ion was achieved by adjusting the pH of the sample carrier stream with aqueous HCl solution. 相似文献
19.
Carrier Transport and Recombination in Efficient “All‐Small‐Molecule” Solar Cells with the Nonfullerene Acceptor IDTBR
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Ru‐Ze Liang Maxime Babics Victoria Savikhin Weimin Zhang Vincent M. Le Corre Sergei Lopatin Zhipeng Kan Yuliar Firdaus Shengjian Liu Iain McCulloch Michael F. Toney Pierre M. Beaujuge 《Liver Transplantation》2018,8(19)
Reaching device efficiencies that can rival those of polymer‐fullerene Bulk Heterojunction (BHJ) solar cells (>10%) remains challenging with the “All‐Small‐Molecule” (All‐SM) approach, in part because of (i) the morphological limitations that prevail in the absence of polymer and (ii) the difficulty to raise and balance out carrier mobilities across the active layer. In this report, the authors show that blends of the SM donor DR3TBDTT (DR3) and the nonfullerene SM acceptor O‐IDTBR are conducive to “All‐SM” BHJ solar cells with high open‐circuit voltages (VOC) >1.1 V and PCEs as high as 6.4% (avg. 6.1%) when the active layers are subjected to a post‐processing solvent vapor‐annealing (SVA) step with dimethyl disulfide (DMDS). Combining electron energy loss spectroscopy (EELS) analyses and systematic carrier recombination examinations, the authors show that SVA treatments with DMDS play a determining role in improving charge transport and reducing non‐geminate recombination for the DR3:O‐IDTBR system. Correlating the experimental results and device simulations, it is found that substantially higher BHJ solar cell efficiencies of >12% can be achieved if the IQE and carrier mobilities of the active layer are increased to >85% and >10?4 cm2 V?1 s?1, respectively, while suppressing the recombination rate constant k to <10?12 cm3 s?1. 相似文献
20.
Sylvia de Pater Johan E. Pinas Paul J. J. Hooykaas Bert J. van der Zaal 《Plant biotechnology journal》2013,11(4):510-515
Previously, we showed that ZFN‐mediated induction of double‐strand breaks (DSBs) at the intended recombination site enhanced the frequency of gene targeting (GT) at an artificial target locus using Agrobacterium‐mediated floral dip transformation. Here, we designed zinc finger nucleases (ZFNs) for induction of DSBs in the natural protoporphyrinogen oxidase (PPO) gene, which can be conveniently utilized for GT experiments. Wild‐type Arabidopsis plants and plants expressing the ZFNs were transformed via floral dip transformation with a repair T‐DNA with an incomplete PPO gene, missing the 5′ coding region but containing two mutations rendering the enzyme insensitive to the herbicide butafenacil as well as an extra KpnI site for molecular analysis of GT events. Selection on butafenacil yielded 2 GT events for the wild type with a frequency of 0.8 × 10?3 per transformation event and 8 GT events for the ZFNs expressing plant line with a frequency of 3.1 × 10?3 per transformation event. Molecular analysis using PCR and Southern blot analysis showed that 9 of the GT events were so‐called true GT events, repaired via homologous recombination (HR) at the 5′ and the 3′ end of the gene. One plant line contained a PPO gene repaired only at the 5′ end via HR. Most plant lines contained extra randomly integrated T‐DNA copies. Two plant lines did not contain extra T‐DNAs, and the repaired PPO genes in these lines were transmitted to the next generation in a Mendelian fashion. 相似文献