bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification of Nucleic Acids by Azobenzene Derivatives and Their Applications in Biotechnology and Nanotechnology
Authors: Li Jing , Wang Xingyu , Liang Xingguo
Published: September 2014

Azobenzene has been widely used as a photoregulator due to its reversible photoisomerization, large structural change between E and Z isomers, high photoisomerization yield, and high chemical stability. On the other hand, some azobenzene derivatives can be used as universal quenchers for many fluorophores. Nucleic acid is a good candidate to be modified because it is not only the template of gene expression but also widely used for building well‐organized nanostructures and nanodevices. Because the size and polarity distribution of the azobenzene molecule is similar to a nucleobase pair, the introduction of azobenzene into nucleic acids has been shown to be an ingenious molecular design for constructing light‐switching biosystems or light‐driven nanomachines. Here we review recent advances in azobenzene‐modified nucleic acids and their applications for artificial regulation of gene expression and enzymatic reactions, construction of photoresponsive nanostructures and nanodevices, molecular beacons, as well as obtaining structural information using the introduced azobenzene as an internal probe. In particular, nucleic acids bearing multiple azobenzenes can be used as a novel artificial nanomaterial with merits of high sequence specificity, regular duplex structure, and high photoregulation efficiency. The combination of functional groups with biomolecules may further advance the development of chemical biotechnology and biomolecular engineering.
Efficient Intramolecular Energy Transfer between Two Fluorophores in a Bis‐Branched [3]Rotaxane
Authors: Yao Jian , Li Hong , Xu Ya‐Nan , Wang Qiao‐Chun , Qu Da‐Hui
Published: September 2014

A bis‐branched [3]rotaxane, with two [2]rotaxane arms separated by an oligo(para‐phenylenevinylene) (OPV) fluorophore, was designed and investigated. Each [2]rotaxane arm employed a difluoroboradiaza‐s‐indacene (BODIPY) dye‐functionalized dibenzo[24]crown‐8 macrocycle interlocked onto a dibenzylammonium in the rod part. The chemical structure of the [3]rotaxane was confirmed and characterized by 1H and 13C NMR spectroscopy and high‐resolution ESI mass spectrometry. The photophysical properties of [3]rotaxane and its reference systems were investigated through UV/Vis absorption, fluorescence, and time‐resolved fluorescence spectroscopy. An efficient energy‐transfer process in [3]rotaxane occurred from the OPV donor to the BODIPY acceptor because of the large overlap between the absorption spectrum of the BODIPY moiety and the emission spectrum of the OPV fluorophore; this shows the important potential of this system for designing functional molecular systems.
o‐Fluorination of Aromatic Azides Yields Improved Azido‐Based Fluorescent Probes for Hydrogen Sulfide: Synthesis, Spectra, and Bioimaging
Authors: Wei Chao , Wang Runyu , Wei Lv , Cheng Longhuai , Li Zhifei , Xi Zhen , Yi Long
Published: September 2014

Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with multiple biological functions. To visualize the endogenous in situ production of H2S in real time, new coumarin‐ and boron‐dipyrromethene‐based fluorescent turn‐on probes were developed for fast sensing of H2S in aqueous buffer and in living cells. Introduction of a fluoro group in the ortho position of the aromatic azide can lead to a greater than twofold increase in the rate of reaction with H2S. On the basis of o‐fluorinated aromatic azides, fluorescent probes with high sensitivity and selectivity toward H2S over other biologically relevant species were designed and synthesized. The probes can be used to in situ to visualize exogenous H2S and D‐cysteine‐dependent endogenously produced H2S in living cells, which makes them promising tools for potential applications in H2S biology.
High‐level secretory expression and purification of unhydroxylated human collagen α1(III) chain in Pichia pastoris GS115
Authors: Li Linbo , Fan Daidi , Ma Xiaoxuan , Deng Jianjun , He Jing
Published: September 2014

Recombinant collagen and gelatin have been applied in biomedical materials field because of products from genetically engineered microorganisms with improved safety, traceability, reproducibility, and homogeneous quality. To obtain high‐level secretory expression of single‐chain full‐length human collagen α1(III) chain (COL3A1) without the N and C telopeptides, the cDNA coding for the human COL3A1 gene was cloned into the secretory expression vector pPIC9K and integrated into Pichia pastoris GS115. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and Western blotting analysis of culture supernatant from the recombinant methylotrophic yeast suggested that the unhydroxylated recombinant human COL3A1 (rhCOL3A1) was secreted into the culture medium, and exhibited an apparent molecular mass of approximately 130 kDa, which is 1.4 times higher than the theoretical one. Finally, the unhydroxylated rhCOL3A1 was purified to greater than 90% purity using a four‐step approach. In addition, methylthiazolydiphenyl‐tetrazolium bromide experiments indicated that low concentration of rhCOL3A1 could promote Baby hamster kidney cell (BHK21) proliferation effectively. The production and purification of rhCOL3A1 described in this study offer a new method for obtaining high level of rhCOL3A1 in relatively pure form, which is suitable for biomedical materials application.
TGFβ and Wnt in Cardiac Outflow Tract Defects in Offspring of Diabetic Pregnancies
Authors: Zhao Zhiyong
Published: September 2014

BACKGROUND

Diabetes mellitus in pregnancy causes defects in infant heart, including the outflow tracts (OFTs). Development of the aorta and pulmonary artery, which are derived from the common OFT in the embryo, is regulated by the transforming growth factor β (TGFβ) and Wnt families, and can be perturbed by hyperglycemia‐generated intracellular stress conditions. However, the underlying cellular and molecular mechanisms remain to be delineated.

METHODS

Female mice were induced diabetic with streptozotocin. Embryonic and fetal OFTs were examined morphologically and histologically. Cell proliferation was assessed using 5’‐bromo‐2’‐deoxyuridine incorporation assay. Oxidative and endoplasmic reticulum (ER) stress markers and TGFβ factors were detected using immunohistochemistry. The expression of genes in the Wnt‐signaling system was assessed using real‐time reverse transcription polymerase chain reaction array. The role of activin‐A in cell proliferation was addressed by treating embryos cultured in high glucose with activin‐A.

RESULTS

Maternal diabetes caused complex abnormalities in the OFTs, including aortic and pulmonary stenosis and persistent truncus arteriosus. The development of the endocardial cushions was suppressed, manifested with insufficient cellularization of the tissues. Cell proliferation was significantly decreased under oxidative and ER stress conditions. The expression of genes in the Wnt signaling was significantly altered. Activin‐A and Smad3 were found to be expressed in the OFT. Treatment with activin‐A rescued cell proliferation in the endocardial cushions.

CONCLUSIONS

Maternal diabetes generates oxidative and ER stress conditions, suppresses TGFβ and Wnt signaling, inhibits cell proliferation and cellularization of the endocardial cushions, leading to OFT septal defects. Activin‐A plays a role in hyperglycemia‐suppressed proliferation of the endocardial cells
Synthesis of Novel Phosphonic‐Type Activity‐Based Probes for Neutrophil Serine Proteases and Their Application in Spleen Lysates of Different Organisms
Authors: Grzywa Renata , Burchacka Ewa , Łęcka Maria , Winiarski Łukasz , Walczak Maciej , Łupicka‐Słowik Agnieszka , Wysocka Magdalena , Burster Timo , Bobrek Kamila , Csencsits‐Smith Keri , Lesner Adam , Sieńczyk Marcin
Published: September 2014

Neutrophils are a type of granulocyte important in the “first line of defense” of the innate immune system. Upon activation, they facilitate the destruction of invading microorganisms by the production of superoxide radicals, as well as the release of the enzymatic contents of their lysozymes. These enzymes include specific serine proteases: cathepsin G, neutrophil elastase, proteinase 3, as well as the recently discovered neutrophil serine protease 4 (NSP4). Under normal conditions, the proteolytic activity of neutrophil proteases is tightly regulated by endogenous serpins; however, this mechanism can be subverted during tissue stress, thereby resulting in the uncontrolled activity of serine proteases, which induce chronic inflammation and subsequent pathology. Herein, we describe the development of low‐molecular‐weight activity‐based probes that specifically target the active sites of neutrophil proteases.
Evaluation of the Calmodulin‐SOX9 Interaction by “Magnetic Fishing” Coupled to Mass Spectrometry
Authors: McFadden Meghan J. , Hryciw Todd , Brown Arthur , Junop Murray S. , Brennan John D.
Published: September 2014

Disruption of calmodulin (CaM)‐based protein interactions has been touted as a potential means for modulating several disease pathways. Among these is SOX9, which is a DNA binding protein that is involved in chrondrocyte differentiation and regulation of the hormones that control sexual development. In this work, we employed a “magnetic fishing”/mass spectrometry assay in conjunction with intrinsic fluorescence to examine the interaction of CaM with the CaM‐binding domain of SOX9 (SOX‐CAL), and to assess the modulation of this interaction by known anti‐CaM compounds. Our data show that there is a high affinity interaction between CaM and SOX‐CAL (27±9 nM), and that SOX‐CAL bound to the same location as the well‐known CaM antagonist melittin; unexpectedly, we also found that addition of CaM‐binding small molecules initially produced increased SOX‐CAL binding, indicative of binding to both the well‐known high‐affinity CaM binding site and a second, lower‐affinity binding site.
Oncogenic nature of a novel mutant AATF and its interactome existing within human cancer cells
Authors: Sharma Shaveta , Kaul Deepak , Arora Mansi , Malik Deepti
Published: September 2014

Since apoptosis presents a natural defense in cancer development, the anti‐apoptotic factor AATF/Che‐1 has emerged as a crucial ‘Epigenomic‐Switch’. We have tried to understand the double‐edged nature of AATF, showing for the first time the conspicuous existence of an aberrant AATF/Che‐1 transcriptome encoding for 23 kDa mutant AATF protein, which evolves its unique interactome within human cancer cells derived from different tissue origins. This mutant AATF along with its interactome consisting of SP1, DNMT3B and Par‐4 ensures cancer cell DNA methylation required for down‐regulation of tumor suppressor genes. Hence, the proposed mutant AATF interactome‐based pathway can have the inherent ability to ensure human cells become and remain cancerous.
Formic Acid Dehydrogenation Catalysed by Tris(TPPTS) Ruthenium Species: Mechanism of the Initial “Fast” Cycle
Authors: Thevenon Arnaud , Frost‐Pennington Ewan , Weijia Gan , Dalebrook Andrew F. , Laurenczy Gábor
Published: September 2014

Water‐soluble ruthenium m‐triphenylphosphinetrisulfonate (TPPTS) complexes are excellent catalysts for formic acid dehydrogenation. Interestingly, the choice of metal catalyst precursor has a direct influence on initial activities. The reaction with hexaaquaruthenium(II) tosylate directly yields bisphosphine complexes in the presence of TPPTS and formic acid, whereas trisphosphine adducts are involved if the reaction starts with ruthenium(III) chloride. We present the results of a series of manometric and spectroscopic experiments that reveal the true nature of these highly active species, and subsequently propose a rational “fast” cycle mechanism explaining this peculiar activity profile.
Grooves of Bundled Single‐Walled Carbon Nanotubes Dramatically Enhance the Activity of the Oxygen Reduction Reaction
Authors: Fujigaya Tsuyohiko , Morita Junichi , Nakashima Naotoshi
Published: September 2014

Nitrogen‐doped graphitic structures (N‐GSs) are promising and cheap catalyst candidates for the oxygen reduction reaction (ORR). In this paper, we describe, first, the synthesis of single‐walled carbon nanotubes (SWNTs) coated by a N‐GS (SWNT/N‐GS) and, second, the dramatic enhancement in the activity of the ORR by using this catalyst relative to that observed for the analogue composite composed of multiwalled carbon nanotubes (MWNTs) coated by a N‐GS (i.e., MWNT/N‐GS). Scanning electron microscopy and gas‐adsorption experiments revealed that the SWNT/N‐GS formed a bundled structure and that superior gas adsorption behavior originated from this groove structure. It is assumed that the grooves of the bundled SWNT/N‐GS dramatically enhance the activity of the ORR owing to superior O2 adsorption on the grooves.
Polyvinyl Alcohol–Borax Slime as Promising Polyelectrolyte for High‐Performance, Easy‐to‐Make Electrochromic Devices
Authors: Alesanco Yolanda , Palenzuela Jesús , Viñuales Ana , Cabañero Germán , Grande Hans J. , Odriozola Ibon
Published: September 2014

A novel slime‐type electrochromic system based on polyvinyl alcohol (PVA) and borax, in combination with a viologen and a redox pair has been developed. On top of overcoming the limitations of both liquid electrolytes, such as the risk of leakage and difficulty of assembly and of solid electrolytes, such as limited transparency and slow response time, this easy‐to‐make slime electrochromic system offers an excellent wettability and transparency and achieves high‐performance in terms of optical contrast (>65 % at 550 nm), switching time (<5 s as estimated for 90 % of the total transmittance change at 550 nm) and cyclability (8 000–10 000). For the electrochromic devices shown here, the CIELAB 1976 color space coordinates at the “on” state were L*=7.12, a*=18.08, and b*=−21.02, corresponding to a purple color. The color efficiencies were 75.5 cm2 C−1 and 149.3 cm2 C−1 for coloration and bleaching processes respectively.
Tailoring the Structure of Hierarchically Porous Zeolite Beta through Modified Orientated Attachment Growth in a Dry Gel System
Authors: Chen Jiao , Hua Weiming , Xiao Yu , Huo Qisheng , Zhu Kake , Zhou Xinggui
Published: September 2014

The crystallization of zeolite beta in a dry gel system is found to follow the orientated attachment growth route, escorted with a temporal morphology change from bulky gel, through aggregation of the particulate to large zeolitic crystals. Modification of the precrystallized gel with organosilanes can be used to tune the morphology of the ultimate beta. When hexadecyltrimethoxysilane (HTS) is employed to modify precrystallized gel, a resumed secondary growth produces a hybrid mesocrystal of agglomerated nanozeolites. Combustive removal of organics leads to the formation of hierarchically porous zeolite beta of 100 to 160 nm, composed of nanocrystal building units ranging from 20 to 40 nm, with a noticeable micropore volume of 0.19 mL g−1 and a meso/macropore size between 5 and 80 nm. Conversely, when 1,8‐bis(triethoxysilyl)octane (BTO) is utilized to modify the same precrystallized gel, assemblages of discrete beta nanozeolite of around 35 nm are generated. These assemblages construct a hierarchical zeolite beta with a micropore volume of 0.20 mL g−1 and auxiliary pores ranging from 5 to 100 nm. Both organosilanes bring about well‐connected hierarchical pore networks. HTS has little effect on the Brønsted/Lewis acidity, whereas BTO causes a substantial reduction of strong Brønsted acid sites. The hierarchical beta zeolite‐supported Pt catalyst exhibits improved catalytic performance for the hydroisomerization of n‐heptane.
Static and Dynamic Properties of 1,1′‐Bi‐2‐naphthol and Its Conjugated Acids and Bases
Authors: Alkorta Ibon , Cancedda Céline , Cocinero Emilio José , Dávalos Juan Z. , Écija Patrica , Elguero José , González Javier , Lesarri Alberto , Ramos Rocio , Reviriego Felipe , Roussel Christian , Uriarte Iciar , Vanthuyne Nicolas
Published: September 2014

Several convergent techniques were used to characterize 1,1′‐bi‐2‐naphthol (BINOL) and some of its properties. Its acidity in the gas‐phase, from neutral species to monoanion, was measured by mass spectrometry. The conformation and structure of BINOL in the gas phase was determined by microwave rotational spectroscopy. NMR experiments in fluorosulfonic acid established that BINOL was monoprotonated on one of the hydroxyl oxygen atoms. The enantiomerization barriers reported in the literature for BINOL under neutral, basic, and acid conditions were analyzed with regard to the species involved. Finally, DFT calculations allowed all of these results to be gathered in a coherent picture of the BINOL structure.
One‐Step Versus Multistep Equilibrium of Carbazole‐Bridged Dinuclear Zinc(II) Complex Formation: Metal‐Assisted π‐Association and ‐Dissociation Processes
Authors: Inukai Norie , Kawai Tsuyoshi , Yuasa Junpei
Published: September 2014

This work demonstrates a selection criteria that determines whether molecular assembly occurs through a one‐step or stepwise manner in ligand‐bridged dinuclear zinc(II) (Zn2+) complex formation, which is associated with the π stacking of building blocks. The building blocks of carbazole ligands (L1 and L4) that contain two imidazole moieties at the 3,6‐positions form 4:2 complexes (i.e., [L]4(Zn2+)2) at a molar ratio of 0.50 ([Zn2+]/[L]0=0.50), thereby providing π stacking between the carbazole ligands. At the molar ratio of 0.67 ([Zn2+]/[L]0=0.67), the 4:2 complexes change to 3:2 complexes (i.e., [L]3(Zn2+)2) with no π‐stacked carbazole unit. In contrast, when the imidazole groups in L1 are replaced with benzoimidazole groups (L3), L3 also yields the 4:2 complex [(L3)4(Zn2+)2] at a molar ratio of 0.50. However, there is no structural transition from (L3)4(Zn2+)2 to other complex species above a molar ratio of 0.50. Similarly, when two imidazole groups are introduced into the carbazole ring at 2,7‐positions (L5), L5 also gives the 4:2 complex [(L5)4(Zn2+)2] that shows no structural transition to other complex species at a higher molar ratio.
Probing the Role of π Interactions in the Reactivity of Oxygen Species: A Case of Ethylzinc Aryloxides with Different Dispositions of Aromatic Rings toward the Metal Center
Authors: Mąkolski Łukasz , Zelga Karolina , Petrus Rafał , Kubicki Dominik , Zarzycki Piotr , Sobota Piotr , Lewiński Janusz
Published: September 2014

Ethylzinc derivatives of ortho‐hydroxybiphenyl and 2,6‐diphenylphenol that bear different nuclearity and dispositions of aromatic rings toward the metal center were synthesized and structurally characterized in the solid state and solution. This family of well‐defined compounds was examined as a model system for the activation of dioxygen mediated by using complexes that feature lack of a redox‐active metal center. Experimental and theoretical studies indicate an essential role in the oxygenation process of intramolecular interactions that involve aromatic subunits. Additionally, novel results for the oxygenation chemistry of alkylzinc compounds, including the isolation and structural characterization of the unique octanuclear aryloxide (hydroxide) compound Zn8(OAr)8(OH)6(O2) with an encapsulated peroxide species, are presented.
Rhodium‐Catalyzed Arylative Cyclization for the Enantioselective Synthesis of (Trifluoromethyl)cyclobutanols
Authors: Johnson Thomas , Choo Ken‐Loon , Lautens Mark
Published: September 2014

A rhodium‐catalyzed cyclization of 1‐(trifluoromethyl)‐4‐alkyn‐1‐ones with arylboronic acids is described to yield a novel class of small rings: (trifluoromethyl)cyclobutanols bearing an exocyclic double bond. The use of a rhodium/chiral diene complex allowed the reaction to proceed under mild conditions, often with high enantioselectivity. An X‐ray crystal structure was obtained confirming the formation of the four‐membered ring products.
Culprit Vessel Only vs Immediate Complete Revascularization in Patients With Acute ST‐Segment Elevation Myocardial Infarction: Systematic Review and Meta‐Analysis
Authors: Sekercioglu Nigar , Spencer Frederick A. , Cruz Lopes Luciane , Guyatt Gordon H.
Published: September 2014

Although multivessel coronary artery disease has been associated with poor health outcomes in patients with acute ST‐segment elevation myocardial infarction (STEMI), the optimal approach to revascularization remains uncertain. The objective of this review was to determine the benefits and harms of culprit vessel only vs immediate complete percutaneous coronary intervention (PCI) in patients with acute STEMI. We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for randomized controlled trials (RCTs). Teams of 2 reviewers, independently and in duplicate, screened titles and abstracts, completed full‐text reviews, and abstracted data. We calculated pooled risk ratios (RRs) and associated 95% confidence intervals (CIs) using random‐effect models for nonfatal myocardial infarction (MI), revascularization, cardiovascular mortality, all‐cause mortality, and adverse events, and used the GRADE approach to rate confidence in estimates of effect. Of 341 patients randomized to complete revascularization and followed to study conclusion, 31 experienced revascularization, as did 80 of 324 randomized to culprit vessel only revascularization (RR: 0.35, 95% CI: 0.24‐0.53). Ten patients in the complete revascularization group and 28 patients in the culprit vessel only revascularization group experienced nonfatal MI (RR: 0.35, 95% CI: 0.17‐0.72). All‐cause mortality and cardiac deaths did not differ between groups (RR: 0.69, 95% CI: 0.40‐1.21 for all‐cause mortality; RR: 0.48, 95% CI: 0.22‐1.04 for cardiac deaths). Pooled data from 3 RCTs suggest that immediate complete revascularization probably reduces revascularization in patients with acute STEMI; although results suggest possible benefits on MI and death, confidence in estimates is low.
Cytopathology fellowship milestones
Authors: Naritoku Wesley Y. , Black‐Schaffer W. Stephen
Published: September 2014

The American Society of Cytopathology has provided guidelines for goals and objectives for cytopathology fellows. There are 90 Accreditation Council for Graduate Medical Education‐accredited cytopathology fellowship training programs in the United States, each with its own unique curriculum designed to achieve these goals and objectives. The Accreditation Council for Graduate Medical Education cytopathology fellowship milestones were developed to ensure some uniformity in the outcomes of the various skill sets and competencies expected of a graduating cytopathology fellow. The rationale, development, and details of the cytopathology fellowship milestones are described herein. Cancer (Cancer Cytopathol) 2014;122:859–865. © 2014 American Cancer Society.
The effect of food and formulation on the pharmacokinetics, safety, and tolerability of GSK1322322 in healthy volunteers
Authors: Naderer Odin , Jones Lori S. , Zhu John , Coffin Mark D. , Kurtinecz Milena , Dumont Etienne
Published: September 2014

GSK1322322 is the first in a new class of antibiotics that inhibit peptide deformylase, necessary for bacterial protein maturation. Previously, low absolute bioavailability was observed for the 1500‐mg oral tablet formulation, resulting in a less than dose‐proportional increase from the 1000‐mg dose. Furthermore, high variability of pharmacokinetic (PK) parameters within cohorts was suggested to be associated with differences in body weight. This open‐label, randomized, 4‐period, crossover, single‐dose phase I study in healthy individuals compared the PK, safety, and tolerability of free base oral tablets under fasted or fed conditions with intravenous and oral mesylate salt solution of GSK1322322 under fasted conditions. Absolute bioavailability of GSK1322322 1500‐mg free base tablets under fasted conditions, fed conditions, and oral mesylate salt solution was 57%, 77%, and 92%, respectively. Moderate‐fat/calorie food intake increased area under the concentration–time curve (AUC0−∞) by 36%, maintained maximum observed concentration (Cmax), and delayed time to Cmax. It appeared that AUC0−∞ decreased with body weight, whereas clearance increased. GSK1322322 administration resulted in only mild‐to‐moderate adverse events. These results support future clinical investigations of the free base oral tablet formulation of GSK1322322 1500 mg after intake of a moderate‐fat/calorie meal, including further investigation of a potential weight‐based dosage change.
Effect of canagliflozin on the pharmacokinetics of glyburide, metformin, and simvastatin in healthy participants
Authors: Devineni Damayanthi , Manitpisitkul Prasarn , Murphy Joseph , Skee Donna , Wajs Ewa , Mamidi Rao N. V. S. , Tian Hong , Vandebosch An , Wang Shean‐Sheng , Verhaeghe Tom , Stieltjes Hans , Usiskin Keith
Published: September 2014

Drug–drug interactions between canagliflozin, a sodium glucose co‐transporter 2 inhibitor, and glyburide, metformin, and simvastatin were evaluated in three phase‐1 studies in healthy participants. In these open‐label, fixed sequence studies, participants received: Study 1‐glyburide 1.25 mg/day (Day 1), canagliflozin 200 mg/day (Days 4–8), canagliflozin with glyburide (Day 9); Study 2‐metformin 2,000 mg/day (Day 1), canagliflozin 300 mg/day (Days 4–7), metformin with canagliflozin (Day 8); Study 3‐simvastatin 40 mg/day (Day 1), canagliflozin 300 mg/day (Days 2–6), simvastatin with canagliflozin (Day 7). Pharmacokinetic parameters were assessed at prespecified intervals. Co‐administration of canagliflozin and glyburide did not affect the overall exposure (maximum plasma concentration [Cmax] and area under the plasma concentration–time curve [AUC]) of glyburide and its metabolites (4‐trans‐hydroxy‐glyburide and 3‐cis‐hydroxy‐glyburide). Canagliflozin did not affect the peak concentration of metformin; however, AUC increased by 20%. Though Cmax and AUC were slightly increased for simvastatin (9% and 12%) and simvastatin acid (26% and 18%) following coadministration with canagliflozin, compared with simvastatin administration alone; however, no effect on active 3‐hydroxy‐3‐methyl‐glutaryl‐CoA (HMG‐CoA) reductase inhibitory activity was observed. There were no serious adverse events or hypoglycemic episodes. No drug–drug interactions were observed between canagliflozin and glyburide, metformin, or simvastatin. All treatments were well‐tolerated in healthy participants.
Boron and other Triel Lewis Acid Centers: From Hypovalency to Hypervalency
Authors: Grabowski Sławomir J.
Published: September 2014

MP2/aug‐cc‐pVTZ calculations were performed on triel trifluorides, ZF3(Z=B, Al, Ga, In, Tl), and their complexes with N2and HCN species, which are acting as Lewis bases. Interaction of the ZF3trigonal structure with a single HCN or N2ligand may lead to a tetrahedral structure with the tetravalent triel atom, whereas interaction of ZF3with two ligands results in a trigonal bipyramidal structure with a pentacoordinate Z atom. Consequently, the Z atom in ZF3compounds suffers from electron deficiency (hypovalency), it obeys the octet rule in ZF3–NCH and ZF3–N2moieties, and it may be considered as a hypervalent center in complexes of ZF3with two ligands. Much weaker interactions are observed for the boron complexes than for the other triel systems. This is because of the lower acidity of the B center relative to that of the other triel centers, and it may be the result of a stronger backbonding effect for BF3than for the other triel trifluorides. Interactions in aluminum complexes are characterized by meaningful electrostatic contributions, whereas for gallium complexes, the most important electron charge shift is observed as a result of complexation. Analysis of the geometry of the triel complexes and of the Z⋅⋅⋅N interactions (triel bonds) in these complexes is based on ab initio calculations as well as on the quantum theory of atoms in molecules and the natural bond orbitals method.
Almost Enclosed Buckyball Joints: Synthesis, Complex Formation, and Computational Simulations of Pentypticene‐Extended Tribenzotriquinacene
Authors: Henne Stefan , Bredenkötter Björn , Alaghemandi Mohammad , Bureekaew Sareeya , Schmid Rochus , Volkmer Dirk
Published: September 2014

We report the synthesis of a tribenzotriquinacene‐based (TBTQ) receptor (3) for C60 fullerene, which is extended by pentiptycene moieties to provide an almost enclosed concave ball bearing. The system serves as a model for a self‐assembling molecular rotor with a flexible and adapting stator. Unexpectedly, nuclear magnetic resonance spectroscopic investigations reveal a surprisingly low complex stability constant of K1=213±37 M−1 for [C60⊂3], seemingly inconsistent with the previously reported TBTQ systems. Molecular dynamics (MD) simulations have been conducted for three different [C60⊂TBTQ] complexes to resolve this. Because of the dominating dispersive interactions, the binding energies increase with the contact area between guest and host, however, only for rigid host structures. By means of free‐energy calculations with an explicit solvent model it can be shown that the novel flexible TBTQ receptor 3 binds weakly because of hampering entropic contributions.
Strong Coupling and Laser Action of Ladder‐Type Oligo(p‐phenylene)s in a Microcavity
Authors: Höfner Michael , Kobin Björn , Hecht Stefan , Henneberger Fritz
Published: September 2014

We investigate the coupling of ladder‐type quarterphenyl to the photon modes of a dielectric ZrOx/SiOx microcavity at ultraviolet wavelengths. For a relatively long cavity (≈10 μm) with high‐reflectivity mirrors (0.998), optically pumped laser action is demonstrated in the weak‐coupling regime. We observe single‐mode operation with a threshold of 0.4 mJ cm−2. Strong coupling is achieved by using a short λ/2 cavity. We find pronounced anti‐crossing features of the molecular (0,0) and (0,1) vibronic transitions and the cavity mode in angle‐dependent reflectivity measurements providing Rabi splittings of (90±10) meV. All these features occur spectrally resonant to the exciton transition of ZnO demonstrating the potential of ladder‐type oligo(p‐phenylene)s for the construction of inorganic/organic hybrid microcavities.
Assessment of Luminescent Downshifting Layers for the Improvement of Light‐Harvesting Efficiency in Dye‐Sensitized Solar Cells
Authors: Hosseini Zahra , Diau Eric Wei‐Guang , Mehrany Khashayar , Taghavinia Nima
Published: September 2014

Luminescence downshifting (LDS) of light can be a practical photon management technique to compensate the narrow absorption band of high‐extinction‐coefficient dyes in dye‐sensitized solar cells (DSSCs). Herein, an optical analysis on the loss mechanisms in a reflective LDS (R‐LDS)/DSSC configuration is reported. For squaraine dye (550–700 nm absorption band) and CaAlSiN3:Eu2+ LDS material (550–700 nm emission band), the major loss channels are found to be non‐unity luminescence quantum efficiency (QE) and electrolyte absorption. By using an ideal LDS layer (QE=100 %), a less absorbing electrolyte (Co‐based), and antireflection coatings, approximately 20 % better light harvesting is obtained. If the absorption/emission band of dye/LDS is shifted to 800 nm, a maximal short‐circuit current density (Jsc) of 22.1 mA cm−2 can be achieved. By putting the LDS layer in front of the DSSC (transmissive mode), more significant loss channels are observed, and hence a lower overall efficiency than the R‐LDS configuration.
Understanding Aqueous Electrolyte Stability through Combined Computational and Magnetic Resonance Spectroscopy: A Case Study on Vanadium Redox Flow Battery Electrolytes
Authors: Vijayakumar Murugesan , Nie Zimin , Walter Eric , Hu Jianzhi , Liu Jun , Sprenkle Vincent , Wang Wei
Published: September 2014

The investigation of the vanadium electrolyte stability issue on the molecular‐level solvation structure and the dynamics has led to the successful designing of mixed acid‐based vanadium electrolytes. This new mixed‐acid based electrolyte system render approximately 70 % increase in energy density (≈40 Wh L−1) and approximately 80 % increase in stable temperature window (−10 to +50 °C) compared with conventional sulfuric acid‐based vanadium electrolyte. Through a comprehensive study by density functional theory and nuclear magnetic resonance spectroscopies, the improved stability is attributed to the hydrochloric acid as optimal cosolvent providing chloride anions for a ligand‐exchange process in the vanadium solvation structure. The role of the chloride counteranion in the solvation structure and dynamics of vanadium species was studied using combined magnetic resonance spectroscopy and DFT‐based theoretical methods. The solvation phenomenon of multiple vanadium species and their impact on vanadium redox flow battery electrolyte chemical stability are discussed.
Comparative Analysis of the Olfactory Properties of Silicon/Germanium/Tin Analogues of the Lily‐of‐the‐Valley Odorants Lilial and Bourgeonal
Authors: Dörrich Steffen , Gelis Lian , Wolf Steffen , Sunderkötter Astrid , Mahler Christoph , Guschina Elena , Tacke Reinhold , Hatt Hanns , Kraft Philip
Published: September 2014

The silicon/germanium/tin analogues of the lily‐of‐the‐valley odorants lilial (rac‐1 a), compounds rac‐1 b, rac‐1 c, and rac‐1 d, and bourgeonal (2 a), compounds 2 b, 2 c, and 2 d, were synthesized and characterized for their olfactory properties, including GC–olfactometry studies. Compounds rac‐1 a–c and 2 a–c possess a typical lily‐of‐the‐valley odor, whereas the stanna‐analogues rac‐1 d and 2 d, despite some floral aspects, clearly no longer belong to the lily‐of‐the‐valley family. In both series of the carbon/silicon/germanium/tin analogues studied, the lily‐of‐the‐valley odor decreases in the order of carbon<silicon<germanium<tin. A HEK293 cell line with stable tetracycline‐regulated expression of hOR17‐4 was generated to analyze recombinant hOR17‐4 activation by rac‐1 a–d and 2 a–d by using Ca2+ imaging. Bourgeonal (2 a) showed the highest activation potency, whereas lilial (rac‐1 a) and sila‐bourgeonal (2 b) exhibited lower activation potencies. Sila‐lilial (rac‐1 b), germa‐lilial (rac‐1 c), and stanna‐lilial (rac‐1 d), as well as germa‐bourgeonal (2 c) and stanna‐bourgeonal (2 d), did not activate heterologously expressed hOR17‐4 at the concentrations tested. The carbon/silicon/germanium/tin switch strategy thus showed that the stanna‐derivatives clearly exceeded the molecular dimensions of the odorant receptor(s) responsible for the recognition of lily‐of‐the‐valley odorants, although the receptor affinity was already affected with the sila‐ and germa‐analogues. These data could later be used in the qualitative and quantitative evaluation of computational receptor models.
Activated‐Carbon‐Supported Gold–Cesium(I) as Highly Effective Catalysts for Hydrochlorination of Acetylene to Vinyl Chloride
Authors: Zhao Jia , Xu Jiangtao , Xu Jinhui , Ni Jun , Zhang Tongtong , Xu Xiaoliang , Li Xiaonian
Published: September 2014

The synthesis of vinyl chloride from acetylene by hydrochlorination has gained tremendous interest in coal‐based chemistry. Bimetallic gold–cesium(I)/activated carbon (AuCsI/AC) catalysts were found to have a higher catalytic activity and stability for acetylene hydrochlorination when compared with gold catalysts. Over 1 Au4 CsI/AC catalysts, the maximum conversion of acetylene was 94 % and there was only 5 % C2H2 conversion loss after 50 h of running time. Moreover, the 1 Au4 CsI/AC catalyst delivered a stable performance during a 500 h test with the conversion of acetylene and the selectivity of vinyl chloride reaching more than 99.8 and 99.9 %, respectively. Temperature‐programmed reduction of H2, temperature‐programmed desorption of C2H2, and X‐ray photoelectron spectroscopy techniques were further applied to detect structural information on the AuCsI/AC catalysts. Additives of CsCl indeed stabilized the catalytically active Au3+ species and inhibited the reduction of Au3+ to Au0, thereby improving the activity and long‐term stability of gold‐based catalysts.
In Situ Synthesis of Neutral Dinuclear Rhodium Diphosphine Complexes [{Rh(diphosphine)(μ2‐X)}2]: Systematic Investigations
Authors: Meißner Antje , Preetz Angelika , Drexler Hans‐Joachim , Baumann Wolfgang , Spannenberg Anke , König Anja , Heller Detlef
Published: September 2014

As the workhorses for many applications, neutral dimeric μ2‐X‐bridged diphosphine rhodium complexes of the type [{Rh(diphosphine)(μ2‐X)}2] (X=Cl, OH) are usually prepared in situ by the addition of diphosphine ligands to the rhodium complex [{Rh(diolefin)(μ2‐X)}2] (diolefin=cyclooctadiene (cod) or norbornadiene (nbd)) or [{Rh(monoolefin)2(μ2‐Cl)}2] (monoolefin=cyclooctene (coe) or ethylene (C2H4)). The in situ procedure has been investigated for the diphosphines 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP), 5,5′‐bis(diphenylphosphino)‐4,4′‐bi‐1,3‐benzodioxole (SEGPHOS), 5,5′‐bis[di(3,5‐xylyl)phosphino]‐4,4′‐bi‐1,3‐benzodioxole (DM‐SEGPHOS), 5,5′‐bis[di(3,5‐di‐tert‐butyl‐4‐methoxyphenyl)phosphino]‐4,4′‐bi‐1,3‐benzodioxole (DTBM‐SEGPHOS), 2,2′‐bis(diphenylphosphino)‐1,1′‐dicyclopentane (BICP), 1‐[2‐(diphenylphosphino)ferrocenyl]ethyldi‐tert‐butylphosphine (PPF‐PtBu2), 1,1′‐bis(diisopropylphosphino)ferrocene (DiPPF), 1,2‐bis(diphenylphosphino)ethane (DPPE), 1,2‐bis(o‐methoxyphenylphosphino)ethane (DIPAMP), 4,5‐bis(diphenylphosphinomethyl)‐2,2‐dimethyl‐1,3‐dioxalane (DIOP), 1,2‐bis(2,5‐dimethylphospholano)benzene (Me‐DuPHOS), 1,4‐bis(diphenylphosphino)butane (DPPB), and 1,3‐bis(diphenylphosphino)propane (DPPP); the resulting complexes have been characterized by 31P NMR spectroscopy and, in most cases, also by X‐ray analysis. Depending on the diphosphine ligand, the solvent, the temperature, and the rhodium precursor, species other than the desired one [{Rh(diphosphine)(μ2‐X)}2] are formed, for example, [(diolefin)Rh(μ2‐Cl)2Rh(diphosphine)], [Rh(diphosphine)(diolefin)]+, [Rh(diphosphine)2]+, and [Rh(diphosphine)(diolefin)(Cl)]. The results clearly show that the in situ method commonly applied for precatalyst preparation cannot be regarded as an optimal strategy for the formation of such neutral [{Rh(diphosphine)(μ2‐X)}2] complexes.
Hole‐Transporting Small Molecules Based on Thiophene Cores for High Efficiency Perovskite Solar Cells
Authors: Li Hairong , Fu Kunwu , Boix Pablo P. , Wong Lydia H. , Hagfeldt Anders , Grätzel Michael , Mhaisalkar Subodh G. , Grimsdale Andrew C.
Published: September 2014

Two new electron‐rich molecules, 2,3,4,5‐tetra[4,4′‐bis(methoxyphenyl)aminophen‐4“‐yl]‐thiophene (H111) and 4,4′,5,5′‐tetra[4,4′‐bis(methoxyphenyl)aminophen‐4”‐yl]‐2,2′‐bithiophene (H112), which contain thiophene cores with arylamine side groups, are reported. When used as the hole‐transporting material (HTM) in perovskite‐based solar cell devices, power conversion efficiencies of up to 15.4 % under AM 1.5G solar simulation were obtained. This is the highest efficiency achieved with HTMs not composed of 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) and its isomers. Both HTMs, especially H111, have great potential to replace expensive spiro‐OMeTAD given their much simpler and less expensive syntheses.
Interacting effects of age, density, and weather on survival and current reproduction for a large mammal
Authors: Richard Emmanuelle , Simpson Steven E. , Medill Sarah A. , McLoughlin Philip D.
Published: September 2014

Individual‐based study of natural populations allows for accurate and precise estimation of fitness components and the extent to which they might vary with ecological conditions. By tracking the fates of all 701 horses known to have lived on Sable Island, Canada, from 2009 to 2013 (where there is no predation, human interference, or interspecific competition for food), we present a detailed analysis of structured population dynamics with focus on interacting effects of intraspecific competition and weather on reproduction and survival. Annual survival of adult females (0.866 ± 0.107 [ ± SE]) was lower than that of 3‐year‐olds (0.955 ± 0.051), although annual fecundity (producing a foal in a year that was observed during our census) was higher in adults (0.616 ± 0.023) compared to 3‐year‐olds (0.402 ± 0.054). Milder winters and lower densities during gestation increased fecundity. Density negatively impacted survival for all age and sex categories; however, highest adult female survival was observed during high‐density years coupled with a harsh winter, the result expected if pregnancy loss during winter or loss of foals in spring improved survival. Three‐year‐old females, which reproduced at lower rates, experienced higher survival than adults. Our results contrast with a previous study of feral horses that suggested recently feral ungulates might be artificially selected to reproduce even when costs to survival are high. In part, this may be because of the comparably long history of feralization (250 years; at least 25 generations) for Sable Island horses.
Human bone marrow contains a subset of quiescent early memory CD8+ T cells characterized by high CD127 expression and efflux capacity
Authors: Kudernatsch Robert F. , Letsch Anne , Guerreiro Manuel , Löbel Madlen , Bauer Sandra , Volk Hans‐Dieter , Scheibenbogen Carmen
Published: September 2014

Even today it is still not completely understood how CD8+ T‐cell memory is maintained long term. Since bone marrow (BM) is a niche for immunological memory, we sought to identify long‐lasting early memory CD8+ T cells in this compartment. To achieve this, we looked for CD8+ T cells that are able to efflux Rhodamine 123, a typical property of stem cells. Indeed, we identified a distinct subset of CD8+ T cells in BM, with the capacity to efflux and high CD127 expression. These CD127hi effluxers are conventional CD8+ T cells exhibiting a broad TCR‐Vβ repertoire and are generated in response to viral peptides in vitro. CD127hi effluxer CD8+ T cells have an early memory phenotype defined by preferential TNF‐α production and a Bcl‐2hi, KLRG‐1low profile. This population has long telomeres and shows constitutively low frequencies of Ki‐67 expression ex vivo, but has a high proliferative and differentiation capacity in vitro. However, IL‐15 downmodulates CD127 in CD127hi effluxer CD8+ T cells in vitro. Consequently, the CD127low effluxer subset may comprise cells recently exposed to IL‐15. Taken together, CD127hi effluxer CD8+ T cells represent a novel population of early memory T cells resident in BM with properties required for long‐lived memory.
Exploring the Effects of Axial Pseudohalide Ligands on the Photophysical and Cyclic Voltammetry Properties and Molecular Structures of MgII Tetraphenyl/porphyrin Complexes
Authors: Ezzayani Khaireddine , Denden Zouhour , Najmudin Shabir , Bonifácio Cecilia , Saint‐Aman Eric , Loiseau Frédérique , Nasri Habib
Published: September 2014

The (meso‐tetraphenylporphyrinato)magnesium(II) complexes with azido (1), cyanato‐N (2), and thiocyanato‐N (3) ligands were prepared by using 2.2.2‐cryptand to solubilize the azide, cyanato, and thiocyanato salts in dichloromethane solvent. These species were characterized by UV/Vis and IR spectroscopy, mass spectrometry, and electrochemistry. The first reduction potential and the two first oxidation potentials of the porphyrin rings of these species are not affected by the nature of the axial ligand, and an unusual third irreversible oxidation of the porphyrin ring is observed. The anodic behavior of the magnesium azide derivative is complicated by the appearance of additional signals for ligand‐centered electron transfers that originate from the release of the azido ligand of 1. The room‐temperature fluorescence spectra of the magnesium complexes 1–3 indicate that the Soret and Q bands are not particularly affected by the nature of the axial ligands. The quantum yields of the S1→S0 fluorescence are between 0.10 and 0.19, and the fluorescence lifetimes range between 3.7 and 6.1 ns at room temperature. Complexes 1–3 crystallize in the monoclinic crystal system in the same space group, P21/n. The molecular structure of 1 is the first example of a magnesium azide complex. The average equatorial magnesium–Npyrrole bond lengths (Mg–Np) are higher than those of the related pentacoordinate magnesium porphyrin species and decreases from 1 [2.1187(16) Å] to 2 [2.1108(15) Å] to 3 [2.0962(13) Å]; the distance between the magnesium center and the 24‐atom mean plane of the porphyrin ring (Mg–PC) also decreases from 1 to 2 to 3 with values of 0.6629(7), 0.6598(7), and 0.5797(6) Å, respectively. Complex 1 shows major doming and saddle distortions, whereas 2–3 exhibit relatively high ruffling and moderate doming deformations. The molecular structure of 1 is stabilized by weak intermolecular C–H···N hydrogen bonds between one carbon atom of the phenyl ring and the terminal nitrogen atom of the azido ligand, and the lattice of 2 exhibits weak intermolecular C–H···O H bonds between one carbon atom of the phenyl ring and the terminal oxygen atom of the NCO– ligand. The crystal structure of 3 is mainly sustained by weak intermolecular C–H···Cg π interactions between a carbon atom of 2.2.2‐cryptand and the centroid of one pyrrole ring.
A Pair of Enantiopure Cubane‐Type CuII4O4 Clusters: Synthesis, Structure, Chirality and Magnetism
Authors: Yin Ji , Yin Ting‐Ting , Gao Chen , Wang Bing‐Wu , Zhu Yuan‐Yuan , Wu Zong‐Quan , Gao Song
Published: September 2014

A pair of enantiopure cubane‐type CuII4O4 clusters was constructed from simple chiral ligands (R or S)‐2‐[(2‐hydroxy‐1‐phenylethylimino)methyl]phenol (H2LR or S). Single‐crystal X‐ray diffraction studies demonstrated that complexes 1R and 1S are enantiomers. They consist of a CuII4O4 cubane core in which the four CuII centres are linked by a μ3‐oxo bridge. The four CuII ions in one cluster are all in a distorted square‐pyramidal geometry. Circular dichroism (CD) spectroscopy also confirmed that complexes 1R and 1S are enantiomers and that the chirality was successfully transferred and amplified from the ligand to the coordination environment of the CuII ions. Magnetic susceptibility measurements show an overall antiferromagnetic interaction which could be fitted by using MAGPACK with a two parameter model (J1 = –5.58 cm–1, J2 = 3.80 cm–1).
Microwave‐Enhanced Asymmetric Transfer Hydrogenation of N‐(tert‐Butylsulfinyl)imines
Authors: Pablo Óscar , Guijarro David , Yus Miguel
Published: September 2014

Microwave irradiation has considerably enhanced the efficiency of the asymmetric transfer hydrogenation of N‐(tert‐butylsulfinyl)imines in isopropyl alcohol catalyzed by a ruthenium complex bearing the achiral ligand 2‐amino‐2‐methylpropan‐1‐ol. In addition to shortening reaction times for the transfer hydrogenation processes to only 30 min, the amounts of ruthenium catalyst and isopropyl alcohol can be considerably reduced in comparison with our previous procedure assisted by conventional heating, which diminishes the environmental impact of this new protocol. This methodology can be applied to aromatic, heteroaromatic and aliphatic N‐(tert‐butylsulfinyl)ketimines, leading, after desulfinylation, to the expected primary amines in excellent yields and with enantiomeric excesses of up to 96 %.
Iodine Sensing by AgI and AgI1−xClx
Authors: Clinsha P. C. , Gnanasekar K. I. , Jayaraman V. , Gnanasekaran T.
Published: September 2014

Compositions of nominal formula, AgI1−xClx (x=0–0.25) were prepared by soft chemical method. The synthesized compositions were characterized by various physicochemical techniques. The studies revealed the formation of solid solution of AgCl in AgI up to 5 mol %. The composition AgI0.95Cl0.05 exhibited marginally higher conductivity than AgI. Electrochemical sensors were assembled using AgI and AgI0.95Cl0.05. Iodine sensing properties of these two potentiometric sensors were elucidated. Preliminary results show that I2 can be sensed down to ∼10 vppm.