bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracking of dendritic cell migration into lymph nodes using molecular imaging with sodium iodide symporter and enhanced firefly luciferase genes
Authors: Lee Ho Won , Yoon Seung Yun , Singh Thoudam Debraj , Choi Yoon Ju , Lee Hong Je , Park Ji Young , Jeong Shin Young , Lee Sang-Woo , Ha Jeoung-Hee , Ahn Byeong-Cheol , Jeon Yong Hyun , Lee Jaetae
Published: May 2015

We sought to evaluate the feasibility of molecular imaging using the human sodium iodide symporter (hNIS) gene as a reporter, in addition to the enhanced firefly luciferase (effluc) gene, for tracking dendritic cell (DCs) migration in living mice. A murine dendritic cell line (DC2.4) co-expressing hNIS and effluc genes (DC/NF) was established. For the DC-tracking study, mice received either parental DCs or DC/NF cells in the left or right footpad, respectively and combined I-124 PET/CT and bioluminescence imaging (BLI) were performed. In vivo PET/CT imaging with I-124 revealed higher activity of the radiotracer in the draining popliteal lymph nodes (DPLN) of the DC/NF injection site at day 1 than DC injection site (p < 0.05). The uptake value further increased at day 4 (p < 0.005). BLI also demonstrated migration of DC/NF cells to the DPLNs at day 1 post-injection and signals at the DPLNs were much higher at day 4. These data support the feasibility of hNIS reporter gene imaging in the tracking of DC migration to lymphoid organs in living mice. DCs expressing the NIS reporter gene could be a useful tool to optimize various strategies of cell-based immunotherapy.
Fat/carbohydrate ratio but not energy density determines snack food intake and activates brain reward areas
Authors: Hoch Tobias , Kreitz Silke , Gaffling Simone , Pischetsrieder Monika , Hess Andreas
Published: May 2015

The snack food potato chips induces food intake in ad libitum fed rats, which is associated with modulation of the brain reward system and other circuits. Here, we show that food intake in satiated rats is triggered by an optimal fat/carbohydrate ratio. Like potato chips, an isocaloric fat/carbohydrate mixture influenced whole brain activity pattern of rats, affecting circuits related e.g. to reward/addiction, but the number of modulated areas and the extent of modulation was lower compared to the snack food itself.
Finding and tracing human MSC in 3D microenvironments with the photoconvertible protein Dendra2
Authors: Caires Hugo R. , Gomez-Lazaro Maria , Oliveira Carla M. , Gomes David , Mateus Denisa D. , Oliveira Carla , Barrias Cristina C. , Barbosa Mário A. , Almeida Catarina R.
Published: May 2015

Mesenchymal Stem/Stromal Cells (MSC) are a promising cell type for cell-based therapies - from tissue regeneration to treatment of autoimmune diseases - due to their capacity to migrate to damaged tissues, to differentiate in different lineages and to their immunomodulatory and paracrine properties. Here, a simple and reliable imaging technique was developed to study MSC dynamical behavior in natural and bioengineered 3D matrices. Human MSC were transfected to express a fluorescent photoswitchable protein, Dendra2, which was used to highlight and follow the same group of cells for more than seven days, even if removed from the microscope to the incubator. This strategy provided reliable tracking in 3D microenvironments with different properties, including the hydrogels Matrigel and alginate as well as chitosan porous scaffolds. Comparison of cells mobility within matrices with tuned physicochemical properties revealed that MSC embedded in Matrigel migrated 64% more with 5.2 mg protein/mL than with 9.6 mg/mL and that MSC embedded in RGD-alginate migrated 51% faster with 1% polymer concentration than in 2% RGD-alginate. This platform thus provides a straightforward approach to characterize MSC dynamics in 3D and has applications in the field of stem cell biology and for the development of biomaterials for tissue regeneration.
Quantitative assessment of the association between AXIN2 rs2240308 polymorphism and cancer risk
Authors: Gong Juan , Jiang Yuan , Hao Ningbo , Zhu Bo , Li Yongsheng
Published: May 2015

Axin2 is involved in the regulation of Wnt/β-catenin pathway and implicated in cancer development and progression. The association between AXIN2 rs2240308 polymorphism and cancer risk has been examined in several case-control studies, but the conclusions were conflicting. Here we performed a meta-analysis to evaluate the role of rs2240308 in cancer risk. A total of 8 studies were included in this meta-analysis (1559 cancer cases and 1503 controls). The pooled odds ratios (OR) and the 95% confidence intervals (CIs) were assessed to evaluate the association of the AXIN2 rs2240308 polymorphism with a susceptibility to cancer. A significantly decreased overall cancer risk was observed in the homozygous (TT vs. CC), heterozygous (CT vs. CC), dominant (CT+TT vs. CC) and allelic (T vs. C) models (P < 0.005), rather than that in the recessive (TT vs. CT+CC) model (P = 0.092). AXIN2 polymorphism rs2240308 was also associated with decreased cancer risk under all five models in lung cancer. However, AXIN2 rs2240308 polymorphism was not associated with cancer risk under any above model in Turkish population and under homozygous, heterozygous, recessive models in Japanese population. These findings indicate that AXIN2 rs2240308 polymorphism significantly and race-specifically correlates with decreased cancer risk.
Ultra-broadband and strongly enhanced diffraction with metasurfaces
Authors: Zhang Yong , Zhou Lin , Li Jia-qi , Wang Qian-jin , Huang Cheng-ping
Published: May 2015

Enhanced high-order diffractions which are spatially dispersive are desirable in such as spectroscopy studies, thin-film solar cells, etc. Conventionally, the dielectric gratings can be used to realize the enhanced diffraction, but the facets are usually rugged and optically thick (~μm). Plasmonic materials may exhibit unprecedented ability for manipulating light. Nonetheless, much interest has been focused on the subwavelength metasurfaces working in the zero-order regime. Here, we show that ultra-broadband and strongly enhanced diffraction can be achieved with the super-wavelength metasurfaces. For the purpose, we employ symmetric or asymmetric metal patches on a ground metal plane, which support the localized oscillation of free electrons and enhanced scattering of light. The zero-order reflection is suppressed, giving rise to an enhancement of first-order diffraction (50 ~ 95%) in an ultra-wide bandwidth (600 ~ 1500 nm). The proposed plasmonic structure is planar and ultra-thin (with an etching depth of only 80 nm), showing new potential for constructing compact and efficient dispersive elements.
Impact of spatial dispersion, evolution and selection on Ebola Zaire Virus epidemic waves
Authors: Azarian Taj , Lo Presti Alessandra , Giovanetti Marta , Cella Eleonora , Rife Brittany , Lai Alessia , Zehender Gianguglielmo , Ciccozzi Massimo , Salemi Marco
Published: May 2015

Ebola virus Zaire (EBOV) has reemerged in Africa, emphasizing the global importance of this pathogen. Amidst the response to the current epidemic, several gaps in our knowledge of EBOV evolution are evident. Specifically, uncertainty has been raised regarding the potential emergence of more virulent viral variants through amino acid substitutions. Glycoprotein (GP), an essential component of the EBOV genome, is highly variable and a potential site for the occurrence of advantageous mutations. For this study, we reconstructed the evolutionary history of EBOV by analyzing 65 GP sequences from humans and great apes over diverse locations across epidemic waves between 1976 and 2014. We show that, although patterns of spatial dispersion throughout Africa varied, the evolution of the virus has largely been characterized by neutral genetic drift. Therefore, the radical emergence of more transmissible variants is unlikely, a positive finding, which is increasingly important on the verge of vaccine deployment.
Short-range order of compressed amorphous GeSe2
Authors: Properzi L. , Di Cicco A. , Nataf L. , Baudelet F. , Irifune T.
Published: May 2015

The structure of amorphous GeSe2 (a-GeSe2) has been studied by means of a combination of two-edges X-ray absorption spectroscopy (XAS) and angle-dispersive X-ray diffraction under pressures up to about 30 GPa. Multiple-edge XAS data-analysis of a-GeSe2 at ambient conditions allowed us to reconstruct and compare the first-neighbor distribution function with previous results obtained by neutron diffraction with isotopic substitution. GeSe2 is found to remain amorphous up to the highest pressures attained and a reversible 1.5 eV red-shift of the Ge K-edge energy indicating metallization, occurs between 10 GPa and 15 GPa. Two compression stages are identified by XAS structure refinement. First, a decrease of the first-neighbor distances up to about 10 GPa, in the same pressure region of a previously observed breakdown of the intermediate-range order. Second, an increase of the Ge-Se distances, bond disorder and of the coordination number. This stage is related to a reversible non-isostructural transition involving a gradual conversion from tetra- to octa-hedral geometry which is not yet fully completed at 30 GPa.
Inhibition of STAT3, FAK and Src mediated signaling reduces cancer stem cell load, tumorigenic potential and metastasis in breast cancer
Authors: Thakur Ravi , Trivedi Rachana , Rastogi Namrata , Singh Manisha , Mishra Durga Prasad
Published: May 2015

Cancer stem cells (CSCs) are responsible for aggressive tumor growth, metastasis and therapy resistance. In this study, we evaluated the effects of Shikonin (Shk) on breast cancer and found its anti-CSC potential. Shk treatment decreased the expression of various epithelial to mesenchymal transition (EMT) and CSC associated markers. Kinase profiling array and western blot analysis indicated that Shk inhibits STAT3, FAK and Src activation. Inhibition of these signaling proteins using standard inhibitors revealed that STAT3 inhibition affected CSCs properties more significantly than FAK or Src inhibition. We observed a significant decrease in cell migration upon FAK and Src inhibition and decrease in invasion upon inhibition of STAT3, FAK and Src. Combined inhibition of STAT3 with Src or FAK reduced the mammosphere formation, migration and invasion more significantly than the individual inhibitions. These observations indicated that the anti-breast cancer properties of Shk are due to its potential to inhibit multiple signaling proteins. Shk also reduced the activation and expression of STAT3, FAK and Srcin vivoand reduced tumorigenicity, growth and metastasis of 4T1 cells. Collectively, this study underscores the translational relevance of using a single inhibitor (Shk) for compromising multiple tumor-associated signaling pathways to check cancer metastasis and stem cell load.
Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals
Authors: Wu Wei , Liu Li , Dai Zhigao , Liu Juhua , Yang Shuanglei , Zhou Li , Xiao Xiangheng , Jiang Changzhong , Roy Vellaisamy A.L.
Published: May 2015

Ideal SERS substrates for sensing applications should exhibit strong signal enhancement, generate a reproducible and uniform response and should be able to fabricate in large-scale and low-cost. Herein, we demonstrate low-cost, highly sensitive, disposable and reproducible SERS substrates by means of screen printing Ag nanoparticles (NPs) on a plastic PET (Polyethylene terephthalate) substrates. While there are many complex methods for the fabrication of SERS substrates, screen printing is suitable for large-area fabrication and overcomes the uneven radial distribution. Using as-printed Ag substrates as the SERS platform, detection of various commonly known chemicals have been done. The SERS detection limit of Rhodamine 6G (R6G) is higher than the concentration of 1 × 10−10 M. The relative standard deviation (RSD) value for 784 points on the detection of R6G and Malachite green (MG) is less than 20% revealing a homogeneous SERS distribution and high reproducibility. Moreover, melamine (MA) is detected in fresh liquid-milk without additional pretreatment, which may accelerate the application of rapid on-line detection of MA in liquid milk. Our screen printing method highlights the use of large-scale printing strategies for the fabrication of well-defined functional nanostructures with applications well beyond the field of SERS sensing.
Manipulating Steady Heat Conduction by Sensu-shaped Thermal Metamaterials
Authors: Han Tiancheng , Bai Xue , Liu Dan , Gao Dongliang , Li Baowen , Thong John T. L. , Qiu Cheng-Wei
Published: May 2015

The ability to design the control of heat flow has innumerable benefits in the design of electronic systems such as thermoelectric energy harvesters, solid-state lighting and thermal imagers, where the thermal design plays a key role in performance and device reliability. In this work, we employ one identical sensu-unit with facile natural composition to experimentally realize a new class of thermal metamaterials for controlling thermal conduction (e.g., thermal concentrator, focusing/resolving, uniform heating), only resorting to positioning and locating the same unit element of sensu-shape structure. The thermal metamaterial unit and the proper arrangement of multiple identical units are capable of transferring, redistributing and managing thermal energy in a versatile fashion. It is also shown that our sensu-shape unit elements can be used in manipulating dc currents without any change in the layout for the thermal counterpart. These could markedly enhance the capabilities in thermal sensing, thermal imaging, thermal-energy storage, thermal packaging, thermal therapy and more domains beyond.
Noise-robust recognition of wide-field motion direction and the underlying neural mechanisms in Drosophila melanogaster
Authors: Suzuki Yoshinori , Ikeda Hideaki , Miyamoto Takuya , Miyakawa Hiroyoshi , Seki Yoichi , Aonishi Toru , Morimoto Takako
Published: May 2015

Appropriate and robust behavioral control in a noisy environment is important for the survival of most organisms. Understanding such robust behavioral control has been an attractive subject in neuroscience research. Here, we investigated the processing of wide-field motion with random dot noise at both the behavioral and neuronal level in Drosophila melanogaster. We measured the head yaw optomotor response (OMR) and the activity of motion-sensitive neurons, horizontal system (HS) cells, with in vivo whole-cell patch clamp recordings at various levels of noise intensity. We found that flies had a robust sensation of motion direction under noisy conditions, while membrane potential changes of HS cells were not correlated with behavioral responses. By applying signal classification theory to the distributions of HS cell responses, however, we found that motion direction under noise can be clearly discriminated by HS cells and that this discrimination performance was quantitatively similar to that of OMR. Furthermore, we successfully reproduced HS cell activity in response to noisy motion stimuli with a local motion detector model including a spatial filter and threshold function. This study provides evidence for the physiological basis of noise-robust behavior in a tiny insect brain.
Prognostic value of meta-signature miRNAs in renal cell carcinoma: an integrated miRNA expression profiling analysis
Authors: Tang Kun , Xu Hua
Published: May 2015

To identify a robust panel of microRNA (miRNA) signatures that can distinguish renal cell carcinoma (RCC) from normal kidney using miRNA expression levels. We performed a comprehensive meta-analysis of 29 published studies that compared the miRNA expression profiles of RCC tissues and adjacent normal tissues (NT) to determine candidate miRNAs as prognostic biomarkers for RCC. Using vote-counting strategy and robust rank aggregation method, we identified a statistically significant miRNA meta-signature of two upregulated (miR-21, miR-210) and three downregulated (miR-141, miR-200c and miR-429) miRNAs. X-tile plot was used to generate the optimum cut-off point for the 15 different deregulated miRNAs and Kaplan-Meier method was used to calculate CSS. In a cohort of 45 patients, the high expression of miR-21 (HR: 5.46, 95%CI: 2.02-53.39) and miR-210 (HR: 6.85, 95%CI: 2.13-43.36), the low expression of miR-141 (HR: 0.16, 95%CI: 0.004-0.18), miR-200c (HR: 0.08, 95%CI: 0.01-0.43) and miR-429 (HR: 0.18, 95%CI: 0.02-0.50) were associated with poor cancer-specific survival (CSS) following RCC resection. We also constructed a five-miRNAs-based classifier as a reliable prognostic and predictive tool for CSS in patients with RCC, especially in clear cell RCC (ccRCC) (HR: 5.46, 95% CI: 1.51-19.66). This method might facilitate patient counselling and individualise management of RCC.
Multivalent Aptamer/Gold Nanoparticle–Modified Graphene Oxide for Mass Spectrometry–Based Tumor Tissue Imaging
Authors: Huang Rong-Cing , Chiu Wei-Jane , Po-Jung Lai Irving , Huang Chih-Ching
Published: May 2015

The protein mucin1 (MUC1) is an attractive target for cancer biomarkers because it is overexpressed in most adenocarcinomas. In this study, we exploited a MUC1-binding aptamer (AptMUC1) as a targeting agent for nanoparticle-based imaging systems coupled with laser desorption/ionization mass spectrometry (LDI-MS). We found that AptMUC1-conjugated gold nanoparticles immobilized, through hydrophobic and π–π interactions, on graphene oxide (AptMUC1–Au NPs/GO) bound effectively to MUC1 units on tumor cell membranes. The ultrahigh density and high flexibility of AptMUC1 on the GO surface enhanced the platform’s cooperative and multivalent binding affinity for MUC1 on cell membranes. After we had labeled MUC1-overexpressing MCF-7 cells (human breast adenocarcinoma cell line) with AptMUC1–Au NPs/GO, we used LDI-MS to monitor Au cluster ions ([Aun]+; n = 1–3), resulting in the detection of as few as 100 MCF-7 cells. We also employed this AptMUC1–Au NPs/GO–LDI-MS system to analyze four different MUC1 expression cell lines. In addition, the AptMUC1–Au NPs/GO platform could be used further as a labeling agent for tumor tissue imaging when coupled with LDI-MS. Thus, Apt–Au NPs/GO can function as a highly amplified signal transducer through the formation of large Au clusters ions during LDI-MS analysis.
Achieving high energy absorption capacity in cellular bulk metallic glasses
Authors: Chen S. H. , Chan K. C. , Wu F. F. , Xia L.
Published: May 2015

Cellular bulk metallic glasses (BMGs) have exhibited excellent energy-absorption performance by inheriting superior strength from the parent BMGs. However, how to achieve high energy absorption capacity in cellular BMGs is vital but mysterious. In this work, using step-by-step observations of the deformation evolution of a series of cellular BMGs, the underlying mechanisms for the remarkable energy absorption capacity have been investigated by studying two influencing key factors: the peak stress and the decay of the peak stress during the plastic-flow plateau stages. An analytical model of the peak stress has been proposed and the predicted results agree well with the experimental data. The decay of the peak stress has been attributed to the geometry change of the macroscopic cells, the formation of shear bands in the middle of the struts and the “work-softening” nature of BMGs. The influencing factors such as the effect of the strut thickness and the number of unit cells have also been investigated and discussed. Strategies for achieving higher energy absorption capacity in cellular BMGs have been proposed.
Development of a highly sensitive fluorescent light-up probe for G-quadruplexes
Authors: Hu Ming-Hao , Chen Shuo-Bin , Guo Rui-Jun , Ou Tian-Miao , Huang Zhi-Shu , Tan Jia-Heng
Published: May 2015

A highly sensitive and selective fluorescent light-up probe (IZCM-7) was developed for the detection of G-quadruplexes both in solution and in a gel matrix.
Indium tin oxide coated PET film contactless conductivity detector for microchip capillary electrophoresis
Authors: Yan Xingxing , Liu Wenfang , Yuan Yu , Chen Chuanpin
Published: May 2015

Low-cost ITO coated PET film contactless conductivity detector with microchip electrophoresis for the determination of stimulated samples of heavy metal ions.
Fluorescence resonance energy transfer-based aptamer biosensors for bisphenol A using lanthanide-doped KGdF4 nanoparticles
Authors: Duan Nuo , Zhang Hui , Nie Yu , Wu Shijia , Miao Tingting , Chen Jie , Wang Zhouping
Published: May 2015

FRET from KGdF4:Tb3+ NP–aptamers to AuNP–cDNA for the trace detection of BPA.
Highly sensitive turn-on biosensors by regulating fluorescent dye assembly on liposome surfaces
Authors: Seo Sungbaek , Kwon Min Sang , Phillips Andrew W. , Seo Deokwon , Kim Jinsang
Published: May 2015

Herein, we developed a turn-on type liposome-based sensing platform by assembling fluorescence dyes to form H-type aggregation with emission quenching on phospholipid-liposome surfaces. Rationally devised specific interactions between the phospholipid and a target analyte effectively release the fluorescence dyes from H-aggregate, producing a turn-on signal.
Selective catalytic conversion of guaiacol to phenols over a molybdenum carbide catalyst
Authors: Ma Rui , Cui Kai , Yang Le , Ma Xiaolei , Li Yongdan
Published: May 2015

An activated carbon supported α-molybdenum carbide catalyst (α-MoC1−x/AC) showed remarkable activity in the selective deoxygenation of guaiacol to substituted mono-phenols in low carbon number alcohol solvents.
Construction of a reusable multi-enzyme supramolecular device via disulfide bond locking
Authors: Gao Xin , Zhao Chengcheng , Yu Ting , Yang Shengli , Ren Yuhong , Wei Dongzhi
Published: May 2015

A strategy for constructing a reusable multi-enzyme supramolecular device was developed by reprogramming protein–protein interactions and disulfide locking.
Direct accessibility of mixed-metal (iii/ii) acid sites through the rational synthesis of porous metal carboxylates
Authors: Wongsakulphasatch S. , Nouar F. , Rodriguez J. , Scott L. , Le Guillouzer C. , Devic T. , Horcajada P. , Grenèche J.-M. , Llewellyn P. L. , Vimont A. , Clet G. , Daturi M. , Serre C.
Published: May 2015

The scalable and environmentally-friendly synthesis of mixed-metal MOFs is presented.
A mitochondria-targeted colorimetric and ratiometric fluorescent probe for biological SO2derivatives in living cells
Authors: Liu Yu , Li Kun , Wu Ming-Yu , Liu Yan-Hong , Xie Yong-Mei , Yu Xiao-Qi
Published: May 2015

A novel mitochondria-targeted ratiometric fluorescent probe for SO2derivatives was presented, which could selectively respond to HSO3−over other thiol compounds in living cells.
The role of magnetic–electric coupling in exciton-coupled ECD spectra: the case of bis-phenanthrenes
Authors: Jurinovich Sandro , Guido Ciro A. , Bruhn Torsten , Pescitelli Gennaro , Mennucci Benedetta
Published: May 2015

The intrinsic magnetic moment of phenanthrene1Bbtransition has a strong impact on exciton-coupled CD spectra of some bis(phenanthrenes).
Singlet and triplet excitons and charge polarons in cycloparaphenylenes: a density functional theory study
Authors: Liu Jin , Adamska Lyudmyla , Doorn Stephen K. , Tretiak Sergei
Published: May 2015

Upon excitation, electron–phonon coupling leads to spatial localization of the electronic wavefunction and distortion of molecular geometry.
Residual water in ionic liquids: clustered or dissociated?
Authors: Reid Joshua E. S. J. , Walker Adam J. , Shimizu Seishi
Published: May 2015

A rigorous statistical thermodynamic theory clarifies how residual water molecules interact in three dialkylimidazolium ionic liquids.
Comparing the electronic relaxation dynamics of aniline and d7-aniline following excitation at 272–238 nm
Authors: Kirkby Oliver M. , Sala Matthieu , Balerdi Garikoitz , de Nalda Rebeca , Bañares Luis , Guérin Stéphane , Fielding Helen H.
Published: May 2015

Femtosecond studies of electronic relaxation in aniline reveal evidence for a 3-state conical intersection and show that tunnelling is unimportant.
Rhenium(i)-based bridgeless double metallocalix[4]arenes
Authors: Elumalai Palani , Kanagaraj Rajendiran , Marimuthu Rajendiran , Shankar Bhaskaran , Kalita Alok Ch. , Sathiyendiran Malaichamy
Published: May 2015

Bridgeless double metallocalix[4]arenes possessing two orthogonally arranged dinuclear cavitands were obtained from Re2(CO)10, rigid bis-chelating units, and a flexible bis-ditopic N-donor by a one-pot approach.
Sponge-like ionic liquids: a new platform for green biocatalytic chemical processes
Authors: Lozano Pedro , Bernal Juana M. , Garcia-Verdugo Eduardo , Sanchez-Gomez Gregorio , Vaultier Michel , Burguete M. Isabel , Luis Santiago V.
Published: May 2015

Hydrophobic ILs based on cations with long alkyl side-chains are switchable ionic liquid/solid phases with temperature that behave as sponge-like systems (Sponge-Like Ionic Liquids, SLILs), being applied for producing pure liquid compounds (e.g. biodiesel, etc).
Rough hypercuboid based supervised clustering of miRNAs
Authors: Paul Sushmita , Vera Julio
Published: May 2015

The microRNAs are small, endogenous non-coding RNAs found in plants, animals, and some viruses, which function in RNA silencing and post-transcriptional regulation of gene expression.
Reactivity of halfsandwich rare-earth metal methylaluminates toward potassium (2,4,6-tri-tert-butylphenyl)amide and 1-adamantylamine
Authors: Schädle Dorothea , Enders Markus , Schädle Christoph , Maichle-Mössmer Cäcilia , Törnroos Karl W. , Anwander Reiner
Published: May 2015

Donor functionalities drastically affect salt-metathetical methylaluminato–amido exchange reactions in CpRLn(AlMe4)2 by triggering methylaluminate cleavage and C–H bond activation of proximal aliphatic groups.
Base-modified NAD and AMP derivatives and their activity against bacterial DNA ligases
Authors: Pergolizzi Giulia , Cominetti Marco M. D. , Butt Julea N. , Field Robert A. , Bowater Richard P. , Wagner Gerd K.
Published: May 2015

2-Substituted NAD+derivatives are poor substrates, but moderate inhibitors for NAD+-dependent bacterial DNA ligases, acting synergistically with NAD+.
A transition-metal-free Heck-type reaction between alkenes and alkyl iodides enabled by light in water
Authors: Liu Wenbo , Li Lu , Chen Zhengwang , Li Chao-Jun
Published: May 2015

A transition-metal-free coupling protocol between various alkenes and non-activated alkyl iodides is developed by using photoenergy in water.
New dimeric carbazole–benzimidazole mixed ligands for the stabilization of human telomeric G-quadruplex DNA and as telomerase inhibitors. A remarkable influence of the spacer
Authors: Maji Basudeb , Kumar Krishan , Muniyappa K. , Bhattacharya Santanu
Published: May 2015

G-quadruplex DNA binding dimeric ligands and their telomerase inhibition activity are reported.
On the feasibility of determining polymer chemical heterogeneity by SEC with continuous off-line Raman detection
Authors: Pitkänen Leena , Urbas Aaron A. , Striegel André M.
Published: May 2015

Examined here is the feasibility of employing Raman spectroscopy as a detection method in size-exclusion chromatography (SEC) and related macromolecular separations, for the purposes of determining the chemical heterogeneity of copolymers.
Poly(2-oxazoline) molecular brushes by grafting through of poly(2-oxazoline)methacrylates with aqueous ATRP
Authors: Gieseler Dan , Jordan Rainer
Published: May 2015

Well defined molecular brushes of poly(2-oxazoline)s were synthesized by ATRP of oligo- and poly(2-methyl-, 2-ethyl- and 2-isopropyl-2-oxazoline) macromonomers in aqueous solution.
Correction: Organic–inorganic halide perovskite based solar cells – revolutionary progress in photovoltaics
Authors: Liu Xiangye , Zhao Wei , Cui Houlei , Xie Yi'an , Wang Yaoming , Xu Tao , Huang Fuqiang
Published: May 2015

Correction for ‘Organic–inorganic halide perovskite based solar cells – revolutionary progress in photovoltaics’ by Xiangye Liu, et al., Inorg. Chem. Front., 2015, 2, 315–335.
Characterization of malic enzyme and the regulation of its activity and metabolic engineering on lipid production
Authors: Liang Ying-Jie , Jiang Jian-Guo
Published: May 2015

Nowadays, microbial lipids are employed as the feedstock for biodiesel production, which has attracted great attention across the whole world.
Nanochannel arrays etched into hexagonal boron nitride meso-membranes by a focused ion beam
Authors: Linas S. , Fulcrand R. , Cauwet F. , Poinsot B. , Brioude A.
Published: May 2015

Nanochannel arrays are etched into h-BN membranes by a focused ion beam for nanofluidic applications.
(2-Chlorobenzoyloxy)copper(i) catalyzed C–S cross-coupling of di(hetero)aryl disulfides with aryl boronic acids under base-free conditions
Authors: Guo Yan , Quan Zheng-Jun , Da Yu-Xia , Zhang Zhang , Wang Xi-Cun
Published: May 2015

(2-Chlorobenzoyloxy)copper(i) exhibited high activity towards the challenging C–S cross-coupling of di(hetero)aryl disulfides with aryl boric acids with good to excellent yields under base-free conditions.
Amine-catalyzed cascade reactions of ketoses with 1,3-dicarbonyl compounds
Authors: Richter Celin , Voigt Benjamin , Mahrwald Rainer
Published: May 2015

An amine-catalyzed cascade reaction of ketoses with 1,3-dicarbonyl compounds is described.
Patterned catalyst arrays of Pd/SnO2 core–shell nanowires for electrooxidations of biomass-derived alcohols
Authors: Lee Sang Ho , Park Woojin , Lee Byoung Hun , Kim Won Bae
Published: May 2015

High-performance catalyst platforms for electrooxidations of biomass-derived alcohol fuels were developed by designing patterned arrays of Pd/SnO2 core–shell nanowires.
Hierarchical 3-dimensional CoMoO4 nanoflakes on a macroporous electrically conductive network with superior electrochemical performance
Authors: Li Mai , Xu Shaohui , Cherry Christopher , Zhu Yiping , Wu Dajun , Zhang Chi , Zhang Xiaolin , Huang Rong , Qi Ruijuan , Wang Lianwei , Chu Paul K.
Published: May 2015

The paper reports the novel CoMoO4 nanostructure that is fabricated on an ordered Macroporous Electrically conductive Network (MECN) as faradaic electrode.
Efficient ceramic zeolite membranes for CO2/H2 separation
Authors: Korelskiy D. , Ye P. , Fouladvand S. , Karimi S. , Sjöberg E. , Hedlund J.
Published: May 2015

The developed high flux MFI zeolite membranes have been shown to have great potential for selective, cost-effective and sustainable removal of CO2 from synthesis gas.
Ammonia-assisted dehydrofluorination between PVDF and Nafion for highly selective and low-cost proton exchange membranes: a possible way to further strengthen the commercialization of Nafion
Authors: Feng Kai , Tang Beibei , Wu Peiyi
Published: May 2015

Low-cost PEM with high performance is preparedviadehydrofluorination reactions between PVDF and Nafion with the aid of ammonia.
Lithium ion assisted hydration of metal ions in non-aqueous sol–gel inks for high performance metal oxide thin-film transistors
Authors: Park Jee Ho , Oh Jin Young , Baik Hong Koo , Lee Tae Il
Published: May 2015

Enhanced hydration lowers the dehydroxylation temperature of the sol–gel inks, resulting in high-performance metal oxide thin film transistors.
Moisture-responsive films consisting of luminescent polyoxometalates and agarose
Authors: Qiu Yun-Feng , Liu Hong , Liu Jian-Xun , Zhang Chen , Ma Zhuo , Hu Ping-An , Gao Guang-Gang
Published: May 2015

Novel switchable and tunable luminescent composite films consisting of Na9[EuW10O36]·32H2O (EuW10) and agarose have been prepared.
Crossed-beam DC slice imaging of fluorine atom reactions with linear alkanes
Authors: Shi Yuanyuan , Kamasah Alexander , Joalland Baptiste , Suits Arthur G.
Published: May 2015

We report the reaction dynamics of F atom with selected alkanes studied by crossed beam scattering with DC slice ion imaging. The target alkanes are propane, n-butane, and n-pentane. The product alkyl radicals are probed by 157 nm single photon ionization following reaction at a collision energy of ∼10 kcal mol−1. The analyzed data are compared with the corresponding theoretical studies. Reduced translational energy distributions for each system show similar trends with little of the reaction exoergicity appearing in translation. However, the pentane reaction shows a somewhat smaller fraction of available energy in translation than the other two, suggesting greater energy channeled into pentyl internal degrees of freedom. The center-of-mass angular distributions all show backscattering as well as sharp forward scattering that decreases in relative intensity with the size of the molecule. Possible reasons for these trends are discussed.
Extended quantum jump description of vibronic two-dimensional spectroscopy
Authors: Albert Julian , Falge Mirjam , Keß Martin , Wehner Johannes G. , Zhang Pan-Pan , Eisfeld Alexander , Engel Volker
Published: May 2015

We calculate two-dimensional (2D) vibronic spectra for a model system involving two electronic molecular states. The influence of a bath is simulated using a quantum-jump approach. We use a method introduced by Makarov and Metiu [J. Chem. Phys. 111, 10126 (1999)] which includes an explicit treatment of dephasing. In this way it is possible to characterize the influence of dissipation and dephasing on the 2D-spectra, using a wave function based method. The latter scales with the number of stochastic runs and the number of system eigenstates included in the expansion of the wave-packets to be propagated with the stochastic method and provides an efficient method for the calculation of the 2D-spectra.
Density-functional errors in ionization potential with increasing system size
Authors: Whittleton Sarah R. , Sosa Vazquez Xochitl A. , Isborn Christine M. , Johnson Erin R.
Published: May 2015

This work investigates the effects of molecular size on the accuracy of density-functional ionization potentials for a set of 28 hydrocarbons, including series of alkanes, alkenes, and oligoacenes. As the system size increases, delocalization error introduces a systematic underestimation of the ionization potential, which is rationalized by considering the fractional-charge behavior of the electronic energies. The computation of the ionization potential with many density-functional approximations is not size-extensive due to excessive delocalization of the incipient positive charge. While inclusion of exact exchange reduces the observed errors, system-specific tuning of long-range corrected functionals does not generally improve accuracy. These results emphasize that good performance of a functional for small molecules is not necessarily transferable to larger systems.
Observation and theory of reorientation-induced spectral diffusion in polarization-selective 2D IR spectroscopy
Authors: Kramer Patrick L. , Nishida Jun , Giammanco Chiara H. , Tamimi Amr , Fayer Michael D.
Published: May 2015

In nearly all applications of ultrafast multidimensional infrared spectroscopy, the spectral degrees of freedom (e.g., transition frequency) and the orientation of the transition dipole are assumed to be decoupled. We present experimental results which confirm that frequency fluctuations can be caused by rotational motion and observed under appropriate conditions. A theory of the frequency-frequency correlation function (FFCF) observable under various polarization conditions is introduced, and model calculations are found to reproduce the qualitative trends in FFCF rates. The FFCF determined with polarization-selective two-dimensional infrared (2D IR) spectroscopy is a direct reporter of the frequency-rotational coupling. For the solute methanol in a room temperature ionic liquid, the FFCF of the hydroxyl (O–D) stretch decays due to spectral diffusion with different rates depending on the polarization of the excitation pulses. The 2D IR vibrational echo pulse sequence consists of three excitation pulses that generate the vibrational echo, a fourth pulse. A faster FFCF decay is observed when the first two excitation pulses are polarized perpendicular to the third pulse and the echo, 〈XXY Y〉, than in the standard all parallel configuration, 〈XXXX〉, in which all four pulses have the same polarization. The 2D IR experiment with polarizations 〈XY XY〉 (“polarization grating” configuration) gives a FFCF that decays even more slowly than in the 〈XXXX〉 configuration. Polarization-selective 2D IR spectra of bulk water do not exhibit polarization-dependent FFCF decays; spectral diffusion is effectively decoupled from reorientation in the water system.
Correlating solvent dynamics and chemical reaction rates using binary solvent mixtures and two-dimensional infrared spectroscopy
Authors: Jones Brynna H. , Huber Christopher J. , Spector Ivan C. , Tabet Anthony M. , Butler RiAnna L. , Hang Ying , Massari Aaron M.
Published: May 2015

Two-dimensional infrared (2D-IR) spectroscopy was performed on Vaska’s complex (VC) and its oxygen adduct (V C-O2) in binary solvent mixtures of chloroform or benzyl alcohol in d6-benzene. The second order rate constants for oxygenation were also measured in these solvent mixtures. The rate constant in chloroform mixtures is linear with mole fraction within the error of the measurements but changes nonlinearly in benzyl alcohol mixtures, displaying a preference for the alcohol over benzene. The rate constants were compared with FTIR spectra of the carbonyl ligand and the frequency-frequency correlation function of this mode determined by 2D-IR. The line shape broadening mechanisms of the linear spectra of the CO bound to VC and V C-O2 are similar to those previously reported for V C-I2. There is a particularly strong correlation between rate constants and homogeneous linewidths of the carbonyl vibration on the V C-O2 product state. Concurrently, the FTIR spectra and spectral diffusion observed by 2D-IR corroborate an increase in solvent heterogeneity around the product. We interpret these results in the context of the potential role of solvent dynamics in facilitating chemical reactivity.
Kinetically induced irreversibility in electro-oxidation and reduction of Pt surface
Authors: Jinnouchi Ryosuke , Kodama Kensaku , Suzuki Takahisa , Morimoto Yu
Published: May 2015

A mean field kinetic model was developed for electrochemical oxidations and reductions of Pt(111) on the basis of density functional theory calculations, and the reaction mechanisms were analyzed. The model reasonably describes asymmetric shapes of cyclic voltammograms and small Tafel slopes of relevant redox reactions observed in experiments without assuming any unphysical forms of rate equations. Simulations using the model indicate that the oxidation of Pt(111) proceeds via an electrochemical oxidation from Pt to PtOH and a disproportionation reaction from PtOH to PtO and Pt, while its reduction proceeds via two electrochemical reductions from PtO to PtOH and from PtOH to Pt.
Semi-stochastic full configuration interaction quantum Monte Carlo: Developments and application
Authors: Blunt N. S. , Smart Simon D. , Kersten J. A. F. , Spencer J. S. , Booth George H. , Alavi Ali
Published: May 2015

We expand upon the recent semi-stochastic adaptation to full configuration interaction quantum Monte Carlo (FCIQMC). We present an alternate method for generating the deterministic space without a priori knowledge of the wave function and present stochastic efficiencies for a variety of both molecular and lattice systems. The algorithmic details of an efficient semi-stochastic implementation are presented, with particular consideration given to the effect that the adaptation has on parallel performance in FCIQMC. We further demonstrate the benefit for calculation of reduced density matrices in FCIQMC through replica sampling, where the semi-stochastic adaptation seems to have even larger efficiency gains. We then combine these ideas to produce explicitly correlated corrected FCIQMC energies for the beryllium dimer, for which stochastic errors on the order of wavenumber accuracy are achievable.
Triple-band low frequency ultra-compact metamaterial absorber
Authors: Lin Baoqin , Zhao Shanghong , Da Xinyu , Fang Yingwu , Ma Jiajun , Li Wei , Zhu Zihang
Published: May 2015

A triple-band low frequency ultra-compact metamaterial absorber (MA) is proposed, which is composed of a periodic array of 3D structures constructed in lossy FR4-epoxy dielectric slab, and another ultra-thin grounded dielectric substrate is attached to its bottom. The unit cell can be counted as a combiner of three 3D magnetic resonators, which have similar resonant mechanisms and can all be ultra-compact in size. By adjusting structural parameters of the unit cell, the proposed MA can perform well in absorptions at each low resonant frequency. For example, one MA with unit cell width 10.92 mm exhibits three absorption peaks at 2.151 GHz, 2.283 GHz, and 2.378 GHz with the corresponding absorptivities of 96.5%, 96.8%, and 99.6%, respectively; for the three low frequencies, the width of the unit cell is only 7.8%, 8.3%, or 8.6% of the free space wavelength, respectively. Furthermore, the three absorption peaks can be lowered to 1.220 GHz, 1.281 GHz, and 1.343 GHz when the relative permittivity of the ultra-thin grounded substrate is increased to 9.8. Finally, one waveguide experiment was conducted to verify the proposed MA effectively.
Ion mixing, hydration, and transport in aqueous ionic systems
Authors: Tse Ying-Lung Steve , Voth Gregory A. , Witten Thomas A.
Published: May 2015

The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities.
Light scattering by epitaxial VO2 films near the metal-insulator transition point
Authors: Lysenko Sergiy , Fernández Felix , Rúa Armando , Aparicio Joaquin , Sepúlveda Nelson , Figueroa Jose , Vargas Kevin , Cordero Joseph
Published: May 2015

Experimental observation of metal-insulator transition in epitaxial films of vanadium dioxide is reported. Hemispherical angle-resolved light scattering technique is applied for statistical analysis of the phase transition processes on mesoscale. It is shown that the thermal hysteresis strongly depends on spatial frequency of surface irregularities. The transformation of scattering indicatrix depends on sample morphology and is principally different for the thin films with higher internal elastic strain and for the thicker films where this strain is suppressed by introduction of misfit dislocations. The evolution of scattering indicatrix, fractal dimension, surface power spectral density, and surface autocorrelation function demonstrates distinctive behavior which elucidates the influence of structural defects and strain on thermal hysteresis, twinning of microcrystallites, and domain formation during the phase transition.
Investigation of thermal stability and reliability of HfO2 based resistive random access memory devices with cross-bar structure
Authors: Chand Umesh , Huang Kuan-Chang , Huang Chun-Yang , Ho Chia-Hua , Lin Chen-Hsi , Tseng Tseung-Yuen
Published: May 2015

The effect of the annealing treatment of a HfO2 resistive switching layer and the memory performance of a HfO2-based resistive random access memory (cross-bar structure) device were investigated. Oxygen is released from HfO2 resistive switching layers during vacuum annealing, leading to unstable resistive switching properties. This oxygen release problem can be suppressed by inserting an Al2O3 thin film, which has a lower Gibbs free energy, between the HfO2 layer and top electrode to form a Ti/Al2O3/HfO2/TiN structure. This device structure exhibited good reliability after high temperature vacuum annealing and post metal annealing (PMA) treatments. Moreover, the endurance and retention properties of the device were also improved after the PMA treatment.
Note: Improved calibration of atomic force microscope cantilevers using multiple reference cantilevers
Authors: Sader John E. , Friend James R.
Published: May 2015

Overall precision of the simplified calibration method in J. E. Sader et al., Rev. Sci. Instrum. 83, 103705 (2012), Sec. III D, is dominated by the spring constant of the reference cantilever. The question arises: How does one take measurements from multiple reference cantilevers, and combine these results, to improve uncertainty of the reference cantilever’s spring constant and hence the overall precision of the method? This question is addressed in this note. Its answer enables manufacturers to specify of a single set of data for the spring constant, resonant frequency, and quality factor, from measurements on multiple reference cantilevers. With this data set, users can trivially calibrate cantilevers of the same type.
Two-dimensional spectra of electron collisions with acrylonitrile and methacrylonitrile reveal nuclear dynamics
Authors: Regeta K. , Allan M.
Published: May 2015

Detailed experimental information on the motion of a nuclear packet on a complex (resonant) anion potential surface is obtained by measuring 2-dimensional (2D) electron energy loss spectra. The cross section is plotted as a function of incident electron energy, which determines which resonant anion state is populated, i.e., along which normal coordinate the wave packet is launched, and of the electron energy loss, which reveals into which final states each specific resonant state decays. The 2D spectra are presented for acrylonitrile and methacrylonitrile, at the incident energy range 0.095-1.0 eV, where the incoming electron is temporarily captured in the lowest π∗ orbital. The 2D spectra reveal selectivity patterns with respect to which vibrations are excited in the attachment and de-excited in the detachment. Further insight is gained by recording 1D spectra measured along horizontal, vertical, and diagonal cuts of the 2D spectrum. The methyl group in methacrylonitrile increases the resonance width 7 times. This converts the sharp resonances of acrylonitrile into boomerang structures but preserves the essence of the selectivity patterns. Selectivity of vibrational excitation by higher-lying shape resonances up to 8 eV is also reported.
Giant magnetoimpedance biosensor for ferrogel detection: Model system to evaluate properties of natural tissue
Authors: Kurlyandskaya G. V. , Fernández E. , Safronov A. P. , Svalov A. V. , Beketov I. , Beitia A. Burgoa , García-Arribas A. , Blyakhman F. A.
Published: May 2015

Thin-film based magnetoimpedance (MI) sensors were used for quantitative determination of the concentration of magnetic nanoparticles (MNPs) in ferrogels. Ferrogels (model systems for biological tissue) were synthesized by radical polymerization of acrylamide in a stable aqueous suspension of γ-Fe2O3 MNPs fabricated by laser target evaporation. MI [FeNi/Ti]3/Cu/[Ti/FeNi]3/Ti sensitive elements were prepared by sputtering. Thorough structural and magnetic studies of MNPs, ferrogels, and multilayered sensitive element insure the complete characterization of biosensor prototype. The MI response of the sensitive element was carefully evaluated in initial state and in the presence of ferrogels with different concentration of iron oxide MNPs from 0 to 2.44 wt. %, which produced systematic changes of the MI in a frequency span of 300 kHz to 400 MHz.