bluuebunny/crossref_metadata_2025 huggingface dataset:
Single-photon non-linear optics with a quantum dot in a waveguide
Authors: Javadi A. , Söllner I. , Arcari M. , Hansen S. Lindskov , Midolo L. , Mahmoodian S. , Kiršanskė G , Pregnolato T. , Lee E. H. , Song J. D. , Stobbe S. , Lodahl P.
Published: October 2015

Strong non-linear interactions between photons enable logic operations for both classical and quantum-information technology. Unfortunately, non-linear interactions are usually feeble and therefore all-optical logic gates tend to be inefficient. A quantum emitter deterministically coupled to a propagating mode fundamentally changes the situation, since each photon inevitably interacts with the emitter, and highly correlated many-photon states may be created. Here we show that a single quantum dot in a photonic-crystal waveguide can be used as a giant non-linearity sensitive at the single-photon level. The non-linear response is revealed from the intensity and quantum statistics of the scattered photons, and contains contributions from an entangled photon–photon bound state. The quantum non-linearity will find immediate applications for deterministic Bell-state measurements and single-photon transistors and paves the way to scalable waveguide-based photonic quantum-computing architectures.
S-nitrosylation triggers ABI5 degradation to promote seed germination and seedling growth
Authors: Albertos Pablo , Romero-Puertas María C. , Tatematsu Kiyoshi , Mateos Isabel , Sánchez-Vicente Inmaculada , Nambara Eiji , Lorenzo Oscar
Published: October 2015

Plant survival depends on seed germination and progression through post-germinative developmental checkpoints. These processes are controlled by the stress phytohormone abscisic acid (ABA). ABA regulates the basic leucine zipper transcriptional factor ABI5, a central hub of growth repression, while the reactive nitrogen molecule nitric oxide (NO) counteracts ABA during seed germination. However, the molecular mechanisms by which seeds sense more favourable conditions and start germinating have remained elusive. Here we show that ABI5 promotes growth via NO, and that ABI5 accumulation is altered in genetic backgrounds with impaired NO homeostasis. S-nitrosylation of ABI5 at cysteine-153 facilitates its degradation through CULLIN4-based and KEEP ON GOING E3 ligases, and promotes seed germination. Conversely, mutation of ABI5 at cysteine-153 deregulates protein stability and inhibition of seed germination by NO depletion. These findings suggest an inverse molecular link between NO and ABA hormone signalling through distinct posttranslational modifications of ABI5 during early seedling development.
The post-vaccine microevolution of invasive Streptococcus pneumoniae
Authors: Cremers Amelieke J. H. , Mobegi Fredrick M. , de Jonge Marien I. , van Hijum Sacha A. F. T. , Meis Jacques F. , Hermans Peter W. M. , Ferwerda Gerben , Bentley Stephen D. , Zomer Aldert L.
Published: October 2015

The 7-valent pneumococcal conjugated vaccine (PCV7) has affected the genetic population of Streptococcus pneumoniae in pediatric carriage. Little is known however about pneumococcal population genomics in adult invasive pneumococcal disease (IPD) under vaccine pressure. We sequenced and serotyped 349 strains of S. pneumoniae isolated from IPD patients in Nijmegen between 2001 and 2011. Introduction of PCV7 in the Dutch National Immunization Program in 2006 preluded substantial alterations in the IPD population structure caused by serotype replacement. No evidence could be found for vaccine induced capsular switches. We observed that after a temporary bottleneck in gene diversity after the introduction of PCV7, the accessory gene pool re-expanded mainly by genes already circulating pre-PCV7. In the post-vaccine genomic population a number of genes changed frequency, certain genes became overrepresented in vaccine serotypes, while others shifted towards non-vaccine serotypes. Whether these dynamics in the invasive pneumococcal population have truly contributed to invasiveness and manifestations of disease remains to be further elucidated. We suggest the use of whole genome sequencing for surveillance of pneumococcal population dynamics that could give a prospect on the course of disease, facilitating effective prevention and management of IPD.
Visual Identification of Light-Driven Breakage of the Silver-Dithiocarbamate Bond by Single Plasmonic Nanoprobes
Authors: Gao Peng Fei , Yuan Bin Fang , Gao Ming Xuan , Li Rong Sheng , Ma Jun , Zou Hong Yan , Li Yuan Fang , Li Ming , Huang Cheng Zhi
Published: October 2015

Insight into the nature of metal-sulfur bond, a meaningful one in life science, interface chemistry and organometallic chemistry, is interesting but challenging. By utilizing the localized surface plasmon resonance properties of silver nanoparticles, herein we visually identified the photosensitivity of silver-dithiocarbamate (Ag-DTC) bond by using dark field microscopic imaging (iDFM) technique at single nanoparticle level. It was found that the breakage of Ag-DTC bond could be accelerated effectively by light irradiation, followed by a pH-dependent horizontal or vertical degradation of the DTC molecules, in which an indispensable preoxidation process of the silver was at first disclosed. These findings suggest a visualization strategy at single plasmonic nanoparticle level which can be excellently applied to explore new stimulus-triggered reactions and might also open a new way to understand traditional organic reaction mechanisms.
DNA methylation signatures of long intergenic noncoding RNAs in porcine adipose and muscle tissues
Authors: Zhou Zhong-Yin , Li Aimin , Wang Li-Gang , Irwin David M , Liu Yan-Hu , Xu Dan , Han Xu-Man , Wang Lu , Wu Shi-Fang , Wang Li-Xian , Xie Hai-Bing , Zhang Ya-Ping
Published: October 2015

Long intergenic noncoding RNAs (lincRNAs) are one of the major unexplored components of genomes. Here we re-analyzed a published methylated DNA immunoprecipitation sequencing (MeDIP-seq) dataset to characterize the DNA methylation pattern of pig lincRNA genes in adipose and muscle tissues. Our study showed that the methylation level of lincRNA genes was higher than that of mRNA genes, with similar trends observed in comparisons of the promoter, exon or intron regions. Different methylation pattern were observed across the transcription start sites (TSS) of lincRNA and protein-coding genes. Furthermore, an overlap was observed between many lincRNA genes and differentially methylated regions (DMRs) identified among different breeds of pigs, which show different fat contents, sexes and anatomic locations of tissues. We identify a lincRNA gene, linc-sscg3623, that displayed differential methylation levels in backfat between Min and Large White pigs at 60 and 120 days of age. We found that a demethylation process occurred between days 150 and 180 in the Min and Large White pigs, which was followed by remethylation between days 180 and 210. These results contribute to our understanding of the domestication of domestic animals and identify lincRNA genes involved in adipogenesis and muscle development.
Highly sensitive and selective sugar detection by terahertz nano-antennas
Authors: Lee Dong-Kyu , Kang Ji-Hun , Lee Jun-Seok , Kim Hyo-Seok , Kim Chulki , Hun Kim Jae , Lee Taikjin , Son Joo-Hiuk , Park Q-Han , Seo Minah
Published: October 2015

Molecular recognition and discrimination of carbohydrates are important because carbohydrates perform essential roles in most living organisms for energy metabolism and cell-to-cell communication. Nevertheless, it is difficult to identify or distinguish various carbohydrate molecules owing to the lack of a significant distinction in the physical or chemical characteristics. Although there has been considerable effort to develop a sensing platform for individual carbohydrates selectively using chemical receptors or an ensemble array, their detection and discrimination limits have been as high in the millimolar concentration range. Here we show a highly sensitive and selective detection method for the discrimination of carbohydrate molecules using nano-slot-antenna array-based sensing chips which operate in the terahertz (THz) frequency range (0.5–2.5 THz). This THz metamaterial sensing tool recognizes various types of carbohydrate molecules over a wide range of molecular concentrations. Strongly localized and enhanced terahertz transmission by nano-antennas can effectively increase the molecular absorption cross sections, thereby enabling the detection of these molecules even at low concentrations. We verified the performance of nano-antenna sensing chip by both THz spectra and images of transmittance. Screening and identification of various carbohydrates can be applied to test even real market beverages with a high sensitivity and selectivity.
Overshoot during phenotypic switching of cancer cell populations
Authors: Sellerio Alessandro L. , Ciusani Emilio , Ben-Moshe Noa Bossel , Coco Stefania , Piccinini Andrea , Myers Christopher R. , Sethna James P. , Giampietro Costanza , Zapperi Stefano , La Porta Caterina A. M.
Published: October 2015

The dynamics of tumor cell populations is hotly debated: do populations derive hierarchically from a subpopulation of cancer stem cells (CSCs), or are stochastic transitions that mutate differentiated cancer cells to CSCs important? Here we argue that regulation must also be important. We sort human melanoma cells using three distinct cancer stem cell (CSC) markers — CXCR6, CD271 and ABCG2 — and observe that the fraction of non-CSC-marked cells first overshoots to a higher level and then returns to the level of unsorted cells. This clearly indicates that the CSC population is homeostatically regulated. Combining experimental measurements with theoretical modeling and numerical simulations, we show that the population dynamics of cancer cells is associated with a complex miRNA network regulating the Wnt and PI3K pathways. Hence phenotypic switching is not stochastic, but is tightly regulated by the balance between positive and negative cells in the population. Reducing the fraction of CSCs below a threshold triggers massive phenotypic switching, suggesting that a therapeutic strategy based on CSC eradication is unlikely to succeed.
Dynamics of quantum correlation between separated nitrogen-vacancy centers embedded in plasmonic waveguide
Authors: Yang Wan-li , An Jun-Hong , Zhang Cheng-jie , Chen Chang-yong , Oh C. H.
Published: October 2015

We investigate the dynamics of quantum correlation between two separated nitrogen vacancy centers (NVCs) placed near a one-dimensional plasmonic waveguide. As a common medium of the radiation field of NVCs propagating, the plasmonic waveguide can dynamically induce quantum correlation between the two NVCs. It is interesting to find that such dynamically induced quantum correlation can be preserved in the long-time steady state by locally applying individual driving on the two NVCs. In particular, we also show that a large degree of quantum correlation can be established by this scheme even when the distance between the NVCs is much larger than their operating wavelength. This feature may open new perspectives for devising active decoherence-immune solid-state optical devices and long-distance NVC-based quantum networks in the context of plasmonic quantum electrodynamics.
Integrated multi-omics analyses reveal the pleiotropic nature of the control of gene expression by Puf3p
Authors: Kershaw Christopher J. , Costello Joseph L. , Talavera David , Rowe William , Castelli Lydia M. , Sims Paul F. G. , Grant Christopher M. , Ashe Mark P. , Hubbard Simon J. , Pavitt Graham D.
Published: October 2015

The PUF family of RNA-binding proteins regulate gene expression post-transcriptionally. Saccharomyces cerevisiae Puf3p is characterised as binding nuclear-encoded mRNAs specifying mitochondrial proteins. Extensive studies of its regulation of COX17 demonstrate its role in mRNA decay. Using integrated genome-wide approaches we define an expanded set of Puf3p target mRNAs and quantitatively assessed the global impact of loss of PUF3 on gene expression using mRNA and polysome profiling and quantitative proteomics. In agreement with prior studies, our sequencing of affinity-purified Puf3-TAP associated mRNAs (RIP-seq) identified mRNAs encoding mitochondrially-targeted proteins. Additionally, we also found 720  new mRNA targets that predominantly encode proteins that enter the nucleus. Comparing transcript levels in wild-type and puf3∆ cells revealed that only a small fraction of mRNA levels alter, suggesting Puf3p determines mRNA stability for only a limited subset of its target mRNAs. Finally, proteomic and translatomic studies suggest that loss of Puf3p has widespread, but modest, impact on mRNA translation. Taken together our integrated multi-omics data point to multiple classes of Puf3p targets, which display coherent post-transcriptional regulatory properties and suggest Puf3p plays a broad, but nuanced, role in the fine-tuning of gene expression.
Crystal structure, equation of state and elasticity of phase H (MgSiO4H2) at Earth’s lower mantle pressures
Authors: Tsuchiya Jun , Mookherjee Mainak
Published: October 2015

Dense hydrous magnesium silicate (DHMS) phases play a crucial role in transporting water in to the Earth’s interior. A newly discovered DHMS, phase H (MgSiO4H2), is stable at Earth’s lower mantle, i.e., at pressures greater than 30 GPa. Here we report the crystal structure and elasticity of phase H and its evolution upon compression. Using first principles simulations, we have explored the relative energetics of the candidate crystal structures with ordered and disordered configurations of magnesium and silicon atoms in the octahedral sites. At conditions relevant to Earth’s lower mantle, it is likely that phase H is able to incorporate a significant amount of aluminum, which may enhance the thermodynamic stability of phase H. The sound wave velocities of phase H are ~2–4% smaller than those of isostructural δ-AlOOH. The shear wave impedance contrast due to the transformation of phase D to a mixture of phase H and stishovite at pressures relevant to the upper part of the lower mantle could partly explain the geophysical observations. The calculated elastic wave velocities and anisotropies indicate that phase H can be a source of significant seismic anisotropy in the lower mantle.
Great influence of geographic isolation on the genetic differentiation of Myriophyllum spicatum under a steep environmental gradient
Authors: Wu Zhigang , Yu Dan , Wang Zhong , Li Xing , Xu Xinwei
Published: October 2015

Understanding how natural processes affect population genetic structures is an important issue in evolutionary biology. One effective method is to assess the relative importance of environmental and geographical factors in the genetic structure of populations. In this study, we examined the spatial genetic variation of thirteen Myriophyllum spicatum populations from the Qinghai-Tibetan Plateau (QTP) and adjacent highlands (Yunnan-Guizhou Plateau, YGP) by using microsatellite loci and environmental and geographical factors. Bioclim layers, hydrological properties and elevation were considered as environmental variables and reduced by principal component analysis. The genetic isolation by geographic distance (IBD) was tested by Mantel tests and the relative importance of environmental variables on population genetic differentiation was determined by a partial Mantel test and multiple matrix regression with randomization (MMRR). Two genetic clusters corresponding to the QTP and YGP were identified. Both tests and MMRR revealed a significant and strong correlation between genetic divergence and geographic isolation under the influence of environmental heterogeneity at the overall and finer spatial scales. Our findings suggested the dominant role of geography on the evolution of M. spicatum under a steep environmental gradient in the alpine landscape as a result of dispersal limitation and genetic drift.
One-step large-scale deposition of salt-free DNA origami nanostructures
Authors: Linko Veikko , Shen Boxuan , Tapio Kosti , Toppari J. Jussi , Kostiainen Mauri A. , Tuukkanen Sampo
Published: October 2015

DNA origami nanostructures have tremendous potential to serve as versatile platforms in self-assembly -based nanofabrication and in highly parallel nanoscale patterning. However, uniform deposition and reliable anchoring of DNA nanostructures often requires specific conditions, such as pre-treatment of the chosen substrate or a fine-tuned salt concentration for the deposition buffer. In addition, currently available deposition techniques are suitable merely for small scales. In this article, we exploit a spray-coating technique in order to resolve the aforementioned issues in the deposition of different 2D and 3D DNA origami nanostructures. We show that purified DNA origamis can be controllably deposited on silicon and glass substrates by the proposed method. The results are verified using either atomic force microscopy or fluorescence microscopy depending on the shape of the DNA origami. DNA origamis are successfully deposited onto untreated substrates with surface coverage of about 4 objects/mm2. Further, the DNA nanostructures maintain their shape even if the salt residues are removed from the DNA origami fabrication buffer after the folding procedure. We believe that the presented one-step spray-coating method will find use in various fields of material sciences, especially in the development of DNA biochips and in the fabrication of metamaterials and plasmonic devices through DNA metallisation.
Inverse relationship between chitobiase and transglycosylation activities of chitinase-D from Serratia proteamaculans revealed by mutational and biophysical analyses
Authors: Madhuprakash Jogi , Bobbili Kishore Babu , Moerschbacher Bruno M. , Singh Tej Pal , Swamy Musti J. , Podile Appa Rao
Published: October 2015

Serratia proteamaculans chitinase-D (SpChiD) has a unique combination of hydrolytic and transglycosylation (TG) activities. The TG activity of SpChiD can be used for large-scale production of chito-oligosaccharides (CHOS). The multiple activities (hydrolytic and/or chitobiase activities and TG) of SpChiD appear to be strongly influenced by the substrate-binding cleft. Here, we report the unique property of SpChiD substrate-binding cleft, wherein, the residues Tyr28, Val35 and Thr36 control chitobiase activity and the residues Trp160 and Trp290 are crucial for TG activity. Mutants with reduced (V35G and T36G/F) or no (SpChiDΔ30–42 and Y28A) chitobiase activity produced higher amounts of the quantifiable even-chain TG product with degree of polymerization (DP)-6, indicating that the chitobiase and TG activities are inversely related. In addition to its unprecedented catalytic properties, unlike other chitinases, the single modular SpChiD showed dual unfolding transitions. Ligand-induced thermal stability studies with the catalytically inactive mutant of SpChiD (E153A) showed that the transition temperature increased upon binding of CHOS with DP2–6. Isothermal titration calorimetry experiments revealed the exceptionally high binding affinities for E153A to CHOS with DP2–6. These observations strongly support that the architecture of SpChiD substrate-binding cleft adopted to control chitobiase and TG activities, in addition to usual chitinase-mediated hydrolysis.
Graphene-supported Pd catalyst for highly selective hydrogenation of resorcinol to 1, 3-cyclohexanedione through giant π-conjugate interactions
Authors: Wei Zuojun , Pan Ruofei , Hou Yaxin , Yang Yao , Liu Yingxin
Published: October 2015

The selective hydrogenation of resorcinol (RES) to 1, 3-cyclohexanedione (1,3-CHD) without the addition of alkali is a big challenge. In this article, a novel reduced graphene oxide (rGO) supported Pd catalyst was prepared through co-reduction method, over which we obtained 99.9% of resorcinol conversion and 94.2% of the ever-reported highest 1,3-cyclohexanedione selectivity at 25 °C in only CH2Cl2 solvent. The excellent selectivity was contributed to the strong π-π and p-π interactions between the graphene nanosheet and the benzene ring as well as hydroxyl in RES molecule. The followed adsorption experiment and Raman analysis also showed the existence of aromatic graphite structures in rGO, which exhibited stronger adsorption towards RES than towards 1,3-CHD.
Testicular expression of the Lin28/let-7 system: Hormonal regulation and changes during postnatal maturation and after manipulations of puberty
Authors: Sangiao-Alvarellos S. , Manfredi-Lozano M. , Ruiz-Pino F. , León S. , Morales C. , Cordido F. , Gaytán F. , Pinilla L. , Tena-Sempere M.
Published: October 2015

The Lin28/let-7 system, which includes the RNA-binding proteins, Lin28a/Lin28b and let-7 miRNAs, has emerged as putative regulator of puberty and male gametogenesis; yet, its expression pattern and regulation in postnatal testis remain ill defined. We report herein expression profiles of Lin28 and let-7 members and related mir-145 and mir-132, in rat testis during postnatal maturation and in models of altered puberty and hormonal deregulation. Neonatal expression of Lin28a and Lin28b was low and rose markedly during the infantile period; yet, expression patterns diverged thereafter, with persistently elevated levels only for Lin28b, which peaked at puberty. Let-7a, let-7b, mir-132 and mir-145 showed profiles opposite to Lin28b. In fact, let-7b and mir-145 were abundant in pachytene spermatocytes, but absent in elongating spermatids, where high expression of Lin28b was previously reported. Perturbation of puberty by neonatal estrogenization reverted the Lin28/let-7 expression ratio; expression changes were also detected in other models of delayed puberty, due to early photoperiod or nutritional manipulations. In addition, hypophysectomy or growth hormone (GH) deficiency revealed regulation of this system by gonadotropins and GH. Our data document the expression profiles of the Lin28/let-7 system in rat testis along postnatal/pubertal maturation and their perturbation in models of pubertal and hormonal manipulation.
N-donor ligands enhancing luminescence properties of seven Zn/Cd(ii) MOFs based on a large rigid π-conjugated carboxylate ligand
Authors: Ye Run-Ping , Zhang Xin , Zhai Ji-Quan , Qin Ye-Yan , Zhang Lei , Yao Yuan-Gen , Zhang Jian
Published: October 2015

Aggregation-induced emission (AIE) has been identified and studied based on a bulky π-conjugated ligand (H2IDPA) with Zn/CdII metals.
Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study
Authors: McGregor James , Li Ruoyu , Zeitler J. Axel , D'Agostino Carmine , Collins James H. P. , Mantle Mick D. , Manyar Haresh , Holbrey John D. , Falkowska Marta , Youngs Tristan G. A. , Hardacre Christopher , Stitt E. Hugh , Gladden Lynn F.
Published: October 2015

90 molH2O% is identified as a critical composition at which alcohol–water interactions are maximised; with 4–5 H2O molecules present in the hydration shell per 2-propanol.
Radiation-induced transformations of matrix-isolated formic acid: evidence for the HCOOH → HOCO + H channel
Authors: Ryazantsev Sergey V. , Feldman Vladimir I.
Published: October 2015

HOCO radicals are produced under X-ray irradiation of isolated formic acid at low temperatures, and possible mechanisms and astrochemical implications are discussed.
Nickel-catalyzed direct alkynylation of C(sp2)–H bonds of amides: an “inverse Sonogashira strategy” to ortho-alkynylbenzoic acids
Authors: Landge Vinod G. , Shewale Chinmay H. , Jaiswal Garima , Sahoo Manoj K. , Midya Siba P. , Balaraman Ekambaram
Published: October 2015

Nickel-catalyzed direct alkynylation of C(sp2)–H bonds of amides using commercially available, inexpensive 8-aminoquinoline as a removable bidentate directing group is described.
Group 9 bimetallic carbonyl permethylpentalene complexes
Authors: Chadwick F. Mark , Ashley Andrew E. , Cooper Robert T. , Bennett Luke A. , Green Jennifer C. , O'Hare Dermot M.
Published: October 2015

We describe the synthesis, structure and bonding of the first iridium and rhodium permethylpentalene complexes,syn-[M(CO)2]2(μ:η5:η5-Pn*) (M = Rh, Ir).
Efficient conversion of carbon dioxide at atmospheric pressure to 2-oxazolidinones promoted by bifunctional Cu(ii)-substituted polyoxometalate-based ionic liquids
Authors: Wang Mei-Yan , Song Qing-Wen , Ma Ran , Xie Jia-Ning , He Liang-Nian
Published: October 2015

Cu(ii)-substituted polyoxometalate-based ionic liquids were successfully developed as halogen-free bifunctional catalysts for carboxylative cyclization of atmospheric CO2 with propargylic amines.
One-step hydrothermal synthesis of photoluminescent carbon nitride dots derived from ionic liquids
Authors: Xiao Deli , Li Siqiao , Liu Shubo , He Hua , Lu Jinrong
Published: October 2015

A novel hydrothermal approach to synthesize fluorescent carbon nitride dots derived from ionic liquids has been reported. In comparison with previous methods, this method bears several unique merits, such as being clean, cheap, convenient and having a potential to advance large-scale industrialization.
Facile synthesis of arylthiophenyl-functionalized diketopyrrolopyrrole derivatives via direct C–H arylation: characterization and utilization in organic electronic devices
Authors: Palai Akshaya Kumar , Kumar Amit , Sim Kyoseung , Kwon Jaehyuk , Shin Tae Joo , Jang Soonmin , Cho Sungwoo , Park Seung-Un , Pyo Seungmoon
Published: October 2015

We report the synthesis and characterization of three arylthiophenyl-functionalized diketopyrrolopyrrole derivatives with different end-capping groups via direct C–H arylation.
In situ SeO2promoted synthesis of CdSe/PPy and Se/PPy nanocomposites and their utility in optical sensing for detection of Hg2+ions
Authors: Khanna Pawan K. , Bhanoth Sreenu , Dhanwe Vaishali , Kshirsagar Anuraj , More Priyesh
Published: October 2015

The reaction of selenium dioxide, a mild oxidizing agent, leads to the initiation of polymerization of pyrrole. The presence of cadmium metal can generate CdSe/PPy nanocomposites however, without it, Se/ PPy composites have been isolated.
Enhanced antibacterial activity of new “composite” biocides with both N-chloramine and quaternary ammonium moieties
Authors: Ning Chenxi , Li Lingdong , Logsetty Sarvesh , Ghanbar Sadegh , Guo Melinda , Ens Werner , Liu Song
Published: October 2015

Combining bothN-chloramine and quaternary ammonium moieties in one molecule results in a new biocide with better antibacterial activity.
Superlubricity of the DLC films-related friction system at elevated temperature
Authors: Zeng Qunfeng , Eryilmaz Osman , Erdemir Ali
Published: October 2015

Superlubricity is defined as a sliding regime in which friction or resistance to sliding almost vanishes. High temperature superlubricity is realized by the DLC films-related friction system.
Self-directedly assembled porphyrin thin films with high photoactivity
Authors: Yuan Bing , Ge Riyue , Kang Shi-Zhao , Qin Lixia , Li Guodong , Li Xiangqing
Published: October 2015

A highly photoactive porphyrin thin films were self-directedly assembled by using 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin cobalt and γ-isocyanatopropyltriethoxysilane as the reactants.
Highly selective and sensitive fluorescence optode membrane for uranyl ion based on 5-(9-anthracenylmethyl)-5-aza-2,8-dithia[9],(2,9)-1,10-phenanthrolinophane
Authors: Shamsipur Mojtaba , Mohammadi Moslem , Taherpour Avat (Arman) , Garau Alessandra , Lippolis Vito
Published: October 2015

A highly sensitive and selective fluorimetric optode membrane based on the enhancement in fluorescence emission of 5-(9-anthracenylmethyl)-5-aza-2,8-dithia[9],(2,9)-1,10-phenanthrolinophane (L) for subnanomolar detection of uranyl ion is presented.
Highly selective and sensitive recognition of histidine based on the oxidase-like activity of Cu2+ions
Authors: Xu Yan , Wu Xiao-Qiong , Shen Jiang-Shan , Zhang Hong-Wu
Published: October 2015

A simple, highly sensitive and selective PL sensing platform for histidine has been developed, based on the oxidase-like activity of Cu2+ions.
Microbial production of phenol via salicylate decarboxylation
Authors: Ren Yanxian , Yang Sen , Yuan Qipeng , Sun Xinxiao
Published: October 2015

A novel phenol biosynthetic pathway was designed and verified inE. coli.
Aceclofenac nanocrystals for improved dissolution: influence of polymeric stabilizers
Authors: Pattnaik Satyanarayan , Swain Kalpana , Rao Jupally Venkateswar , Varun Talla , Prusty K. Baikuntha , Subudhi Sanjeev Kumar
Published: October 2015

SEM of nanocrystals synthesized through bottom up approach.
In situ generation and protonation of the isocyanide/acetylene adduct: a powerful catalyst-free strategy for multicomponent synthesis of ketenimines, aza-dienes, and heterocycles
Authors: Rostamnia Sadegh
Published: October 2015

In addition to isocyanide-based Ugi, Passerini, van Leusen, and Orru multicomponent reactions, a new class of isocyanide/acetylene-based multicomponent reactions, using zwitterionic adducts, have emerged as powerful methods to synthesize biologically interesting molecules.
Synthesis of a novel bifunctional nanocomposite with tunable upconversion emission and magnetic properties
Authors: Cheng Qian , Li Yu , Liu Shouxin , Sui Jiehe , Cai Wei
Published: October 2015

A method of Co2+ ions codoping for significantly enhancing upconversion emission intensity and simultaneous controlling sparamagnetic properties in β-NaYF4:Yb/Er nanoparticles, with well maintaining their morphology and highly disperse.
Development of a red fluorescent light-up probe for highly selective and sensitive detection of vicinal dithiol-containing proteins in living cells
Authors: Wang Yuanyuan , Yang Xiao-Feng , Zhong Yaogang , Gong Xueyun , Li Zheng , Li Hua
Published: October 2015

An environment-sensitive red fluorescent light-up probe for vicinal dithiol-containing proteins (VDPs) in living cells has been successfully developed.
Catalytic activation of a single C–F bond in trifluoromethyl arenes
Authors: Dang Hester , Whittaker Aaron M. , Lalic Gojko
Published: October 2015

Catalytic activation of a single C–F bond in a trifluoromethyl group was used to accomplish highly selective monodefluorination of trifluoromethyl arenes. An investigation of the reaction mechanism suggests the formation of an unexpected intermediate and provides evidence for an unusual reaction pathway responsible for the observed selectivity.
Efficient multicast resource allocation algorithm with limited feedback scheme in single‐frequency networks
Authors: Chen Lei
Published: October 2015

Single‐frequency network (SFN) can provide multimedia broadcast multicast service (MBMS) over a large coverage area, so it receives more and more attention from both academia and industry. However, the application of SFN is still restricted by a large number of feedbacks. Therefore, the authors propose a novel multicast resource allocation algorithm based on limited feedback scheme. In the algorithm, they first design a user limited feedback scheme based on channel gain threshold to effectively reduce feedback load. The scheme determines to which base stations users should report channel state information. Next, to overcome the MBMS capacity limitation drawback, they encode the MBMS data into a base layer and multiple enhancement layers and develop a joint subcarrier and power allocation strategy to maximise the throughput of enhancement layers while guaranteeing the rate requirement of base layer. Simulation results show that the proposed algorithm significantly reduces 83% of the feedback overhead while achieving a comparable multicast throughput performance to the case of full feedback.
High‐performance binary and non‐binary Low‐density parity‐check codes based on affine permutation matrices
Authors: Gholami Mohammad , Alinia Masoumeh
Published: October 2015

Low‐density parity‐check (LDPC) codes from affine permutation matrices, called APM‐LDPC codes, are a class of LDPC codes whose parity‐check matrices consist of zero matrices or APMs of the same orders. APM‐LDPC codes are not quasi‐cyclic (QC), in general. In this study, necessary and sufficient conditions are provided for an APM‐LDPC code to have cycles of length 2l, l ≥ 2, and a deterministic algorithm is given to generate APM‐LDPC codes with a given girth. Unlike Type‐I conventional QC‐LDPC codes, the constructed (J, L) APM‐LDPC codes with the J × L all‐one base matrix can achieve minimum distance greater than (J + 1)! and girth larger than 12. Moreover, the lengths of the constructed APM‐LDPC codes, in some cases, are smaller than the best known lengths reported for QC‐LDPC codes with the same base matrices. Another significant advantage of the constructed APM‐LDPC codes is that they have remarkably fewer cycle multiplicities compared with QC‐LDPC codes with the same base matrices and the same lengths. Simulation results show that the binary and non‐binary constructed APM‐LDPC codes with lower girth outperform QC‐LDPC codes with larger girth.
Achievable rates and outage probability of cognitive radio with dynamic frequency hopping under imperfect spectrum sensing
Authors: Le Anh D. , Herath Sanjeewa P. , Tran Nghi H. , Duong Trung Q. , Shetty Sachin
Published: October 2015

In this study, the authors propose simple methods to evaluate the achievable rates and outage probability of a cognitive radio (CR) link that takes into account the imperfectness of spectrum sensing. In the considered system, the CR transmitter and receiver correlatively sense and dynamically exploit the spectrum pool via dynamic frequency hopping. Under imperfect spectrum sensing, false‐alarm and miss‐detection occur which cause impulsive interference emerged from collisions due to the simultaneous spectrum access of primary and cognitive users. That makes it very challenging to evaluate the achievable rates. By first examining the static link where the channel is assumed to be constant over time, they show that the achievable rate using a Gaussian input can be calculated accurately through a simple series representation. In the second part of this study, they extend the calculation of the achievable rate to wireless fading environments. To take into account the effect of fading, they introduce a piece‐wise linear curve fitting‐based method to approximate the instantaneous achievable rate curve as a combination of linear segments. It is then demonstrated that the ergodic achievable rate in fast fading and the outage probability in slow fading can be calculated to achieve any given accuracy level.
Low‐complexity peak‐to‐average power ratio reduction method for orthogonal frequency‐division multiplexing communications
Authors: Wang Yuewen , Akansu Ali N.
Published: October 2015

The high peak‐to‐average power ratio (PAPR) of the transmitted signal is a major drawback of multicarrier transmission such as orthogonal frequency‐division multiplexing OFDM. A plethora of PAPR reduction techniques has been reported in the literature. Some of the techniques modify the phase and/or amplitude of symbols in the original symbol alphabet (SA) such as selected mapping and partial transmit sequences techniques. However, such methods have shortcomings of a heavy computational burden caused by required multiple inverse fast‐Fourier transform (IFFT) operations and bit error rate performance degradation due to side information (SI). In this study, a low‐complexity PAPR reduction framework is proposed to jointly modify phase and amplitude values of the original symbols in the alphabet. This framework utilises only one IFFT/FFT operator pair for transmultiplexing of symbols without any SI. The merit of the proposed method to design a SA modifier matrix (SAM) for PAPR reduction is shown through performance comparisons for the application scenarios presented in this study.
Spectrum combinatorial double auction for cognitive radio network with ubiquitous network resource providers
Authors: Chen Long , Huang Liusheng , Sun Zehao , Xu Hongli , Guo Hansong
Published: October 2015

Spectrum auction is an emerging economic scheme to stimulate both primary spectrum operators (POs) and secondary users (SUs) to be involved in spectrum sharing. Previous spectrum auction works mostly assume each PO can only have one type spectrum or each SU can only buy homogeneous spectrum bands from the same PO. However, in a ubiquitous network scenario, each PO possesses heterogeneous spectrum resources such as WiFi, 3G and each SU may request different types of spectrum bands from the same PO. Existing auction schemes cannot be used to effectively solve the problem. Therefore, the authors come out with a lightweight combinatorial double auction to tackle this challenge. Since spectrum combinatorial double auction problem is NP‐hard, the authors develop a general greedy algorithm G‐Greedy to solve the problem. Inspired by the recent group‐buying discounts, they also invent an enhanced scheme E‐Greedy to further optimise total utility. They theoretically prove the economy properties of the proposed schemes such as individual rationality, budget balance and truthfulness. Simulation results show that both of the two algorithms can yield higher utilities and are effective.
Nitrogen ion implantation into various materials using 28 GHz electron cyclotron resonance ion source
Authors: Shin Chang Seouk , Lee Byoung-Seob , Choi Seyong , Yoon Jang-Hee , Kim Hyun Gyu , Ok Jung-Woo , Park Jin Yong , Kim Seong Jun , Bahng Jungbae , Hong Jonggi , Lee Seung Wook , Won Mi-Sook
Published: October 2015

The installation of the 28 GHz electron cyclotron resonance ion source (ECRIS) ion implantation beamline was recently completed at the Korea Basic Science Institute. The apparatus contains a beam monitoring system and a sample holder for the ion implantation process. The new implantation system can function as a multipurpose tool since it can implant a variety of ions, ranging hydrogen to uranium, into different materials with precise control and with implantation areas as large as 1–10 mm2. The implantation chamber was designed to measure the beam properties with a diagnostic system as well as to perform ion implantation with an in situ system including a mass spectrometer. This advanced implantation system can be employed in novel applications, including the production of a variety of new materials such as metals, polymers, and ceramics and the irradiation testing and fabrication of structural and functional materials to be used in future nuclear fusion reactors. In this investigation, the first nitrogen ion implantation experiments were conducted using the new system. The 28 GHz ECRIS implanted low-energy, multi-charged nitrogen ions into copper, zinc, and cobalt substrates, and the ion implantation depth profiles were obtained. SRIM 2013 code was used to calculate the profiles under identical conditions, and the experimental and simulation results are presented and compared in this report. The depths and ranges of the ion distributions in the experimental and simulation results agree closely and demonstrate that the new system will enable the treatment of various substrates for advanced materials research.
Coupled pulsating and cellular structure in the propagation of globally planar detonations in free space
Authors: Han Wenhu , Gao Yang , Wang Cheng , Law Chung K.
Published: October 2015

The globally planar detonation in free space is numerically simulated, with particular interest to understand and quantify the emergence and evolution of the one-dimensional pulsating instability and the two-dimensional cellular structure which is inherently also affected by pulsating instability. It is found that the pulsation includes three stages: rapid decay of the overdrive, approach to the Chapman-Jouguet state and emergence of weak pulsations, and the formation of strong pulsations; while evolution of the cellular structure also exhibits distinct behavior at these three stages: no cell formation, formation of small-scale, irregular cells, and formation of regular cells of a larger scale. Furthermore, the average shock pressure in the detonation front consists of fine-scale oscillations reflecting the collision dynamics of the triple-shock structure and large-scale oscillations affected by the global pulsation. The common stages of evolution between the cellular structure and the pulsating behavior, as well as the existence of shock-front pressure oscillation, suggest highly correlated mechanisms between them. Detonations with period doubling, period quadrupling, and chaotic amplitudes were also observed and studied for progressively increasing activation energies.
The length distribution of frangible biofilaments
Authors: Michaels Thomas C. T. , Yde Pernille , Willis Julian C. W. , Jensen Mogens H. , Otzen Daniel , Dobson Christopher M. , Buell Alexander K. , Knowles Tuomas P. J.
Published: October 2015

A number of different proteins possess the ability to polymerize into filamentous structures. Certain classes of such assemblies can have key functional roles in the cell, such as providing the structural basis for the cytoskeleton in the case of actin and tubulin, while others are implicated in the development of many pathological conditions, including Alzheimer’s and Parkinson’s diseases. In general, the fragmentation of such structures changes the total number of filament ends, which act as growth sites, and hence is a key feature of the dynamics of filamentous growth phenomena. In this paper, we present an analytical study of the master equation of breakable filament assembly and derive closed-form expressions for the time evolution of the filament length distribution for both open and closed systems with infinite and finite monomer supply, respectively. We use this theoretical framework to analyse experimental data for length distributions of insulin amyloid fibrils and show that our theory allows insights into the microscopic mechanisms of biofilament assembly to be obtained beyond those available from the conventional analysis of filament mass only.
Shock response of open-cell nanoporous Cu foams: Effects of porosity and specific surface area
Authors: Jian W. R. , Li B. , Wang L. , Yao X. H. , Luo S. N.
Published: October 2015

We investigate the effects of porosity or relative mass density and specific surface area on shock response of open-cell nanoporous Cu foams with molecular dynamics simulations, including compression, shock velocity–particle velocity, and shock temperature curves, as well as shock-induced melting. While porosity still plays the key role in shock response, specific surface area at nanoscales can have remarkable effects on shock temperature and pressure, but its effects on shock velocity and specific volume are negligible. Shock-induced melting of nanofoams still follows the equilibrium melting curve for full-density Cu, and the incipient and complete melting temperatures are established as a function of both relative mass density and specific surface area.
Acoustically induced transparency using Fano resonant periodic arrays
Authors: Amin M. , Elayouch A. , Farhat M. , Addouche M. , Khelif A. , Bağcı H.
Published: October 2015

A three-dimensional acoustic device, which supports Fano resonance and induced transparency in its response to an incident sound wave, is designed and fabricated. These effects are generated from the destructive interference of closely coupled one broad- and one narrow-band acoustic modes. The proposed design ensures excitation and interference of two spectrally close modes by locating a small pipe inside a wider and longer one. Indeed, numerical simulations and experiments demonstrate that this simple-to-fabricate structure can be used to generate Fano resonance as well as acoustically induced transparency with promising applications in sensing, cloaking, and imaging.
Thermoelectric properties of rocksalt ZnO from first-principles calculations
Authors: Alvarado Andrew , Attapattu Jeevake , Zhang Yi , Chen Changfeng
Published: October 2015

Zinc oxide (ZnO) undergoes a pressure-induced structural transition from its normal ambient-pressure wurtzite (WZ) phase to a rocksalt (RS) phase around 10 GPa. A recent experiment shows that the high-pressure RS ZnO phase can be recovered and stabilized at ambient conditions, which raises exciting prospects of expanding the range of properties of ZnO. For a fundamental understanding of the RS ZnO phase, we have performed first-principles calculations to determine its electronic, phonon, and thermodynamic properties at high (20 GPa) and ambient (0 GPa) pressure. Furthermore, we have calculated its electrical and thermal transport properties, which allow an evaluation of its thermoelectric figure of merit ZT at different temperature and doping levels. Our calculations show that the ambient-pressure RS ZnO phase can reach ZT values of 0.25 to 0.3 under both n-type and p-type doping in a large temperature range of 400 K to 800 K, which is considerably lower than the temperature range of 1400 K to 1600 K where WZ ZnO reaches similar ZT values. These results establish RS ZnO as a promising material for thermoelectric devices designed to operate at temperatures desirable for many heat recovery applications.
A comprehensive reliability assessment of residential photovoltaic systems
Authors: Piri Marzieh , Niroomand Mehdi , Hooshmand Rahmat-Allah
Published: October 2015

Due to the growing use of photovoltaic (PV) systems in recent years, the reliability of these systems as one of the most important issues regarding durability and correct performance is important. This paper presents a comprehensive assessment of the reliability of Residential PV System (RPVS) in various conditions based on the Markov model. The systems taken into considerations consist of PV modules, a DC-DC converter, an inverter, an inverter controller, and a maximum power point tracking (MPPT) controller. These systems are considered repairable. To evaluate the effect of the three-phase boost converter and the PV modules on reliability, these systems have been considered towards this specific perspective. Furthermore, the impact of various factors on the reliability of the system components and the entire system is evaluated. Simulation results demonstrate the capacity of the proposed method to assess and comparison of the reliability of different RPVS. Also, the results indicate the impact of various factors such as temperature on it.
Intense transient electric field sensor based on the electro-optic effect of LiNbO3
Authors: Yang Qing , Sun Shangpeng , Han Rui , Sima Wenxia , Liu Tong
Published: October 2015

Intense transient electric field measurements are widely applied in various research areas. An optical intense E-field sensor for time-domain measurements, based on the electro-optic effect of lithium niobate, has been studied in detail. Principles and key issues in the design of the sensor are presented. The sensor is insulated, small in size (65 mm × 15 mm × 15 mm), and suitable for high-intensity (<801 kV/m) electric field measurements over a wide frequency band (10 Hz–10 MHz). The input/output characteristics of the sensor were obtained and the sensor calibrated. Finally, an application using this sensor in testing laboratory lightning impulses and in measuring transient electric fields during switch-on of a disconnector confirmed that the sensor is expected to find widespread use in transient intense electric field measurement applications.
The sRNA NsiR4 is involved in nitrogen assimilation control in cyanobacteria by targeting glutamine synthetase inactivating factor IF7
Authors: Klähn Stephan , Schaal Christoph , Georg Jens , Baumgartner Desirée , Knippen Gernot , Hagemann Martin , Muro-Pastor Alicia M. , Hess Wolfgang R.
Published: October 2015

Significance

A key enzyme in inorganic nitrogen assimilation, glutamine synthetase, is the target of multiple regulatory mechanisms. Here we describe the nitrogen stress-induced RNA 4 (NsiR4), a small regulatory RNA that reduces the expression of inactivating factor 7 (IF7), an inhibitory factor of glutamine synthetase in cyanobacteria. The expression of NsiR4 is under positive control through the nitrogen control transcription factor (NtcA). NtcA also induces the transcription of the glutamine synthetase gene and represses the gene encoding IF7. Therefore, NsiR4 is a new player in the NtcA-mediated regulation of nitrogen assimilation, which is important for adaptations to rapid changes in available nitrogen sources and concentrations.