bluuebunny/crossref_metadata_2025 huggingface dataset:
Manipulating Topological States by Imprinting Non-Collinear Spin Textures
Authors: Streubel Robert , Han Luyang , Im Mi-Young , Kronast Florian , Rößler Ulrich K. , Radu Florin , Abrudan Radu , Lin Gungun , Schmidt Oliver G. , Fischer Peter , Makarov Denys
Published: March 2015

Topological magnetic states, such as chiral skyrmions, are of great scientific interest and show huge potential for novel spintronics applications, provided their topological charges can be fully controlled. So far skyrmionic textures have been observed in noncentrosymmetric crystalline materials with low symmetry and at low temperatures. We propose theoretically and demonstrate experimentally the design of spin textures with topological charge densities that can be tailored at ambient temperatures. Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can be imprinted into the out-of-plane magnetised material. We observe distinct spin textures, e.g. vortices, magnetic swirls with tunable opening angle, donut states and skyrmion core configurations. We show that applying a small magnetic field, a reliable switching between topologically distinct textures can be achieved at remanence.
Genome-wide DNA methylome analysis reveals epigenetically dysregulated non-coding RNAs in human breast cancer
Authors: Li Yongsheng , Zhang Yunpeng , Li Shengli , Lu Jianping , Chen Juan , Wang Yuan , Li Yixue , Xu Juan , Li Xia
Published: March 2015

Despite growing appreciation of the importance of epigenetics in breast cancer, our understanding of epigenetic alterations of non-coding RNAs (ncRNAs) in breast cancer remains limited. Here, we explored the epigenetic patterns of ncRNAs in breast cancers using published sequencing-based methylome data, primarily focusing on the two most commonly studied ncRNA biotypes, long ncRNAs and miRNAs. We observed widely aberrant methylation in the promoters of ncRNAs and this abnormal methylation was more frequent than that in protein-coding genes. Specifically, intergenic ncRNAs were observed to comprise a majority (51.45% of the lncRNAs and 51.57% of the miRNAs) of the aberrantly methylated ncRNA promoters. Moreover, we summarized five patterns of aberrant ncRNA promoter methylation in the context of genomic CpG islands (CGIs), in which aberrant methylation occurred not only on CGIs, but also in regions flanking CGI and in CGI-lacking promoters. Integration with transcriptional datasets enabled us to determine that the ncRNA promoter methylation events were associated with transcriptional changes. Furthermore, a panel of ncRNAs were identified as biomarkers that discriminated between disease phenotypes. Finally, the potential functions of aberrantly methylated ncRNAs were predicted, suggestiong that ncRNAs and coding genes cooperatively mediate pathway dysregulation during the development and progression of breast cancer.
New Cyt-like δ-endotoxins from Dickeya dadantii: structure and aphicidal activity
Authors: Loth Karine , Costechareyre Denis , Effantin Géraldine , Rahbé Yvan , Condemine Guy , Landon Céline , da Silva Pedro
Published: March 2015

In the track of new biopesticides, four genes namelycytA,cytB,cytCandcytDencoding proteins homologous toBacillus thuringiensis(Bt) Cyt toxins have been identified in the plant pathogenic bacteriaDickeya dadantiigenome. Here we show that three Cyt-like δ-endotoxins fromD. dadantii(CytA, CytB and CytC) are toxic to the pathogen of the pea aphidAcyrthosiphon pisumin terms of both mortality and growth rate. The phylogenetic analysis of the comprehensive set of Cyt toxins available in genomic databases shows that the whole family is of limited taxonomic occurrence, though in quite diverse microbial taxa. From a structure-function perspective the 3D structure of CytC and its backbone dynamics in solution have been determined by NMR. CytC adopts a cytolysin fold, structurally classified as a Cyt2-like protein. Moreover, the identification of a putative lipid binding pocket in CytC structure, which has been probably maintained in most members of the Cyt-toxin family, could support the importance of this lipid binding cavity for the mechanism of action of the whole family. This integrative approach provided significant insights into the evolutionary and functional history ofD. dadantiiCyt toxins, which appears to be interesting leads for biopesticides.
Combination of angiotensin-(1–7) with perindopril is better than single therapy in ameliorating diabetic cardiomyopathy
Authors: Hao Panpan , Yang Jianmin , Liu Yanping , Zhang Mingxiang , Zhang Kai , Gao Fei , Chen Yuguo , Zhang Cheng , Zhang Yun
Published: March 2015

We recently found that overexpression of angiotensin (Ang)-converting enzyme 2, which metabolizes Ang-II to Ang-(1–7) and Ang-I to Ang-(1–9), may improve left ventricular remodeling in diabetic cardiomyopathy. Here we aimed to test whether chronic infusion of Ang-(1–7) can dose-dependently ameliorate left ventricular remodeling and function in a rat model of diabetic cardiomyopathy and whether the combination of Ang-(1–7) and Ang-converting enzyme inhibition may be superior to single therapy. Our results showed that Ang-(1–7) treatment dose-dependently ameliorated left ventricular remodeling and dysfunction in diabetic rats by attenuating myocardial fibrosis, myocardial hypertrophy and myocyte apoptosis via both the Mas receptor and angiotensin II type 2 receptor. Furthermore, combining Ang-(1–7) with perindopril provided additional cardioprotection relative to single therapy. Ang-(1–7) administration provides a novel and promising approach for treatment of diabetic cardiomyopathy.
Dietary legume consumption reduces risk of colorectal cancer: evidence from a meta-analysis of cohort studies
Authors: Zhu Beibei , Sun Yu , Qi Lu , Zhong Rong , Miao Xiaoping
Published: March 2015

Previous epidemiological studies on the relation between dietary legume consumption and risk of colorectal cancer (CRC) remain controversial. We conducted a meta-analysis based on prospective cohort studies to investigate the association between dietary legume consumption and risk of CRC. Fourteen cohort studies were finally included, containing a total of 1903459 participants and 12261 cases who contributed 11628960 person-years. We found that higher legume consumption was associated with a decreased risk of CRC (RR, relative risk = 0.91; 95% CI, confidence interval = 0.84–0.98). Subgroup analyses suggested that higher legume consumption was inversely associated with CRC risk in Asian (RR = 0.82; 95% CI = 0.74–0.91) and soybean intake was associated with a decreased risk of CRC (RR = 0.85; 95% CI = 0.73–0.99). Findings from our meta-analysis supported an association between higher intake of legume and a reduced risk of CRC. Further studies controlled for appropriate confounders are warranted to validate the associations.
MiR-181a regulates lipid metabolism via IDH1
Authors: Chu Bo , Wu Ting , Miao Lin , Mei Yide , Wu Mian
Published: March 2015

Lipid metabolism is important for cellular energy homeostasis. Excessive cellular lipid accumulation is associated with various human diseases such as obesity, cardiovascular disease or even cancer. It has been recognized that miR-181a is an important modulator in regulating T lymphocyte differentiation, vascular development and cerebellar neurodegeneration. Here we reports a novel function of miR-181a in the regulation of lipid metabolism. MiR-181a is able to target isocitrate dehydrogenase 1 (IDH1), a metabolic enzyme in TCA cycle. Via targeting IDH1, miR-181a decreases expression of genes involved in lipid synthesis and increases expression of genes involved in β-oxidation, thereafter inhibiting lipid accumulation. MiR-181a transgenic mice show a lower body weight as compared with their wild-type littermates and moreover, miR-181a transgenic mice exhibit less lipid accumulation. Collectively, these findings uncover a novel miR-181a-IDH1 axis that has an important role in regulating lipid metabolism and implicate miR-181a as a potential therapeutic target for lipid metabolism disorders.
Diagnostic accuracy of PLA2R autoantibodies and glomerular staining for the differentiation of idiopathic and secondary membranous nephropathy: an updated meta-analysis
Authors: Dai Huanzi , Zhang Huhai , He Yani
Published: March 2015

The diagnostic performance of M-type phospholipase A2 receptor (PLA2R) autoantibodies and PLA2R glomerular staining in discriminating between idiopathic membranous nephropathy (iMN) and secondary membranous nephropathy (sMN) has not been fully evaluated. We conducted an updated meta-analysis to investigate the accuracy and clinical value of serological anti-PLA2R test and histological PLA2R staining for differentiation iMN from sMN. A total of 19 studies involving 1160 patients were included in this meta-analysis. The overall sensitivity, specificity, diagnostic odds ratio (DOR) and area under the receiver operating characteristic curve (AUROC) of serum anti-PLA2R were 0.68 (95% CI, 0.61–074), 0.97 (95% CI, 0.85–1.00), 73.75 (95% CI, 12.56–432.96) and 0.82 (95% CI, 0.78–0.85), respectively, with substantial heterogeneity (I2 = 86.42%). Subgroup analyses revealed the study design, publication type, study origin, assay method might account for the heterogeneity. Additionally, the overall sensitivity, specificity, DOR and AUROC of glomerular PLA2R staining were 0.78 (95% CI, 0.72–0.83), 0.91 (95% CI, 0.75–0.97), 34.70 (95% CI, 9.93–121.30) and 0.84 (95% CI, 0.81–0.87), respectively, without heterogeneity (I2 = 0%). Serological anti-PLA2R testing has diagnostic value, but it must be interpreted in context with patient clinical characteristics and histological PLA2R staining in seronegative patients is recommended.
The Plasmodium vivax in China: decreased in local cases but increased imported cases from Southeast Asia and Africa
Authors: Feng Jun , Xiao Huihui , Zhang Li , Yan He , Feng Xinyu , Fang Wen , Xia Zhigui
Published: March 2015

Currently the local P. vivax was sharply decreased while the imported vivax malaria increased in China. Despite Southeast Asia was still the main import source of vivax malaria, the trend of Africa become serious, especially for west and central Africa. Herein we have clarified the trend of P. vivax in China from 2004–2012 and made some analysis for the differences of imported vivax back from different regions. There are significantly different of P. vivax between Southeast Asia and Africa, also the difference was observed for different regions in Africa. Additionally, we have explored the possibility for the difference of the P. vivax between migrant workers back from west and central Africa and the prevalence of local population. This reminds us that surveillance and training should be strengthened by medical staffs on the imported P. vivax cases reported especially from west and central Africa, in order to reduce the risk of malaria reintroduction and, specific tools should be developed, as well as the epidemiological study to avoid the misdiagnosis such as P. ovale and P. vivax.
Impedimetric transduction of swelling in pH-responsive hydrogels
Authors: Mac Kenna Nicky , Calvert Paul , Morrin Aoife
Published: March 2015

Schematic of the swelling mechanism: (i) GOx immobilised within a polymer network, (ii) glucose diffusion and (iii) production of gluconic acid/network ionisation. Swelling response of glucose-sensitive hydrogels in 10 mM glucose over time. (After immersion for 24 h in DI water).
Reactive and unreactive pathways in a photochemical ring opening reaction from 2D femtosecond stimulated Raman
Authors: Valley David T. , Hoffman David P. , Mathies Richard A.
Published: March 2015

Two-dimensional femtosecond stimulated Raman spectroscopy (2D-FSRS) is used to probe the structural evolution of a modified cyclohexadiene as it undergoes a photoinduced ring opening reaction.
Simple and complex disorder in binary mixtures with benzene as a common solvent
Authors: Požar Martina , Seguier Jean-Baptiste , Guerche Jonas , Mazighi Redha , Zoranić Larisa , Mijaković Marijana , Kežić-Lovrinčević Bernarda , Sokolić Franjo , Perera Aurélien
Published: March 2015

Substituting benzene for water in computer simulations of binary mixtures, allows one to study the various forms of disorder, without the complications often encountered in aqueous mixtures.
Cancer biomarker detection: recent achievements and challenges
Authors: Wu Li , Qu Xiaogang
Published: March 2015

We provide an overview covering the existing challenges and latest developments in achieving high selectivity and sensitivity cancer-biomarker detection.
Metal-free carbon nanotube–SiC nanowire heterostructures with enhanced photocatalytic H2 evolution under visible light irradiation
Authors: Zhou Xunfu , Li Xin , Gao Qiongzhi , Yuan Jielin , Wen Jiuqing , Fang Yueping , Liu Wei , Zhang Shengsen , Liu Yingju
Published: March 2015

Carbon nanotube–SiC nanowire 1D–1D heterostructures exhibit significantly enhanced photocatalytic H2 evolution activities under visible light irradiation.
Selective catalytic hydrogenation of polycyclic aromatic hydrocarbons promoted by ruthenium nanoparticles
Authors: Bresó-Femenia Emma , Chaudret Bruno , Castillón Sergio
Published: March 2015

Naphthalene, anthracene, triphenylene and pyrene were partially hydrogenated with selectivities between 80% and 100% under mild conditions using ruthenium NPs.
Photo-control of the magnetic properties of Dy(iii) and Ho(iii) homometal coordination polymers bridged by a diarylethene ligand
Authors: Cosquer Goulven , Morimoto Masakazu , Irie Masahiro , Fetoh Ahmed , Breedlove Brian K. , Yamashita Masahiro
Published: March 2015

Two-dimensional Dy(iii) and Ho(iii) homometal coordination polymers containing the DTE ligand were obtained, and the magnetic properties of the open and closed forms were investigated.
Hypervalent iodine mediated alkene difunctionalization of vinylphenols: diastereoselective synthesis of substituted indoles and indolizines
Authors: Zhang Kai , Wang Hang , Zheng Jingfeng , Yu Lei , Ding Hanfeng
Published: March 2015

An efficient and highly diastereoselective synthesis of substituted indoles and indolizines through a hypervalent iodine mediated alkene difunctionalization reaction is described.
Cp2TiCl2-catalyzed cis-hydroalumination of propargylic amines with Red-Al: stereoselective synthesis of Z-configured allylic amines
Authors: Sun Renhong , Liu Jun , Yang Shuang , Chen Ming , Sun Ning , Chen Haoyi , Xie Xin , You Xu , Li Shi , Liu Yuanhong
Published: March 2015

Titanium-catalyzed cis-hydroalumination of propargylic amines with Red-Al provides Z-configured allylic amines in good to excellent yields with high stereoselectivity.
Intramolecular decarboxylative coupling as the key step in copper-catalyzed domino reaction: facile access to 2-(1,3,4-oxadiazol-2-yl)aniline derivatives
Authors: Xu Cheng , Jia Feng-Cheng , Cai Qun , Li Deng-Kui , Zhou Zhi-Wen , Wu An-Xin
Published: March 2015

Novel access to diverse 2-(1,3,4-oxadiazol-2-yl)aniline derivatives has been developed by introducing copper-catalyzed decarboxylative coupling for intramolecular C–O bond formation.
Zirconocene-catalyzed sequential ethylcarboxylation of alkenes using ethylmagnesium chloride and carbon dioxide
Authors: Shao Peng , Wang Sheng , Chen Chao , Xi Chanjuan
Published: March 2015

The zirconocene-catalyzed sequential ethylcarboxylation of alkenes using ethylmagnesium chloride and carbon dioxide has been developed. A range of alkenes were transformed into the corresponding carboxylic acids in high yields.
Copper(i)-catalyzed heteroannulation of [60]fullerene with ketoxime acetates: preparation of novel 1-fulleropyrrolines
Authors: Jiang Sheng-Peng , Su Yi-Tan , Liu Kai-Qing , Wu Qing-Hua , Wang Guan-Wu
Published: March 2015

A cuprous bromide-catalyzed heteroannulation reaction of [60]fullerene with ketoxime acetates has been exploited to prepare novel 1-fulleropyrrolines via N–O bond cleavage and C–C/C–N formation under thermal conditions.
A ratiometric fluorescent probe for in situ quantification of basal mitochondrial hypochlorite in cancer cells
Authors: Hou Ji-Ting , Li Kun , Yang Jin , Yu Kang-Kang , Liao Ye-Xin , Ran Yu-Zhao , Liu Yan-Hong , Zhou Xue-Dong , Yu Xiao-Qi
Published: March 2015

The first mitochondria-targeted ratiometric fluorescent probe to image exogenous and endogenous ClO−was presented with high selectivity and sensitivity.
Structural insights into the cubic–hexagonal phase transition kinetics of monoolein modulated by sucrose solutions
Authors: Reese Caleb W. , Strango Zachariah I. , Dell Zachary R. , Tristram-Nagle Stephanie , Harper Paul E.
Published: March 2015

We use DSC, Avrami theory and density measurements to examine the cubic-inverted hexagonal transition in monoolein.
Selective electrocatalytic hydrogenation using palladium nanoparticles electrochemically formed in layer-by-layer multilayer films
Authors: Villalba M. , Bossi M. L. , Calvo E. J.
Published: March 2015

Sequential adsorption of PdCl42− within weak polyelectrolyte layer-by-layer (LbL) self-assembled multilayer films with further electrochemical reduction to yield Pd0 nanoparticles (Pd-NPs) and later heat treatment.
A metallic superhard boron carbide: first-principles calculations
Authors: Ma Mengdong , Yang Bingchao , Li Zihe , Hu Meng , Wang Qianqian , Cui Lin , Yu Dongli , He Julong
Published: March 2015

This work proposed a new metallic, superhard phase of BC3which might exist in experimentally synthesized BC3.
Dynamic interface charge governing the current–voltage hysteresis in perovskite solar cells
Authors: Zhang Huimin , Liang Chunjun , Zhao Yong , Sun Mengjie , Liu Hong , Liang Jingjing , Li Dan , Zhang Fujun , He Zhiqun
Published: March 2015

Since interface charge changes band bending and thus influences photocurrent, its dynamics governs the current–voltage hysteresis.
Effects of separation distance on the charge transfer interactions in quantum dot–dopamine assemblies
Authors: Ji Xin , Wang Wentao , Mattoussi Hedi
Published: March 2015

We explored the effects of changing the separation distance on the charge transfer interactions between luminescent QD and proximal dopamine (in QD–dopamine assemblies), and the ensuing photoluminescence quenching.
Molecular interactions between gold nanoparticles and model cell membranes
Authors: Hu Peipei , Zhang Xiaoxian , Zhang Chi , Chen Zhan
Published: March 2015

Direct observations of the lipid flip-flop induced by Au NP – model mammalian cell membrane interactions.
Solvent response to fluorine-atom reaction dynamics in liquid acetonitrile
Authors: Dunning G. T. , Murdock D. , Greetham G. M. , Clark I. P. , Orr-Ewing A. J.
Published: March 2015

Solvent restructuring and vibrational cooling follow exothermic fluorine-atom reactions in acetonitrile.
The role of terahertz polariton absorption in the characterization of crystalline iron sulfate hydrates
Authors: Ruggiero Michael T. , Bardon Tiphaine , Strlič Matija , Taday Philip F. , Korter Timothy M.
Published: March 2015

Solid-state density functional theory indicates that polariton absorption plays a central role in understanding the identifying terahertz-frequency spectral features of hydrated iron sulfate compounds.
Influence of support acidity on the performance of size-confined Pt nanoparticles in the chemoselective hydrogenation of acetophenone
Authors: Wang Zichun , Kim Kyung-Duk , Zhou Cuifeng , Chen Mengmeng , Maeda Nobutaka , Liu Zongwen , Shi Jeffrey , Baiker Alfons , Hunger Michael , Huang Jun
Published: March 2015

Chemoselectivity of hydrogenation depends on strength of the covered BAS, whereas the free BAS enhance the rate.
Optimizing the performance of a membrane bio-electrochemical reactor using an anion exchange membrane for wastewater treatment
Authors: Li Jian , He Zhen
Published: March 2015

The use of an anion exchange membrane can significantly improve nitrogen removal in a membrane bioelectrochemical reactor.
Facile green ring-opening polymerization of l-lactide catalyzed by natural kaoline
Authors: Gao Jie , Bao Feng , Wang Duo , Ma Rui , Jiang Sanfeng , Zhang Xu , Yao Yanjin , Han Xiaobing , Yan Chunjie
Published: March 2015

Natural kaoline without any further modification was used as a novel catalyst for the facile green ring-opening polymerization of l-lactide.
Polypeptoids with tunable cloud point temperatures synthesized from N-substituted glycine N-thiocarboxyanhydrides
Authors: Tao Xinfeng , Du Jianwei , Wang Youxiang , Ling Jun
Published: March 2015

Poly(sarcosine-r-N-butylglycine) random copolymers with various MWs and compositions are synthesized from NTA monomers, which exhibit tunable Tcps in aqueous solutions.
Incorporation of crystal violet, methylene blue and safranin O into a copolymer emulsion; the development of a novel antimicrobial paint
Authors: Beech Sidney J. , Noimark Sacha , Page Kristopher , Noor Nuruzzaman , Allan Elaine , Parkin Ivan P.
Published: March 2015

Crystal violet, methylene blue and safranin O were successfully incorporated into a co-polymer emulsion to make a potent antimicrobial paint.
Cost effective urea combustion derived mesoporous-Li2MnSiO4as a novel material for supercapacitors
Authors: Chaturvedi Prerna , Kumar Amit , Sil Anjan , Sharma Yogesh
Published: March 2015

Mesoporous-Li2MnSiO4(LMS) having a surface area of 35 (±2) m2g−1is produced using a very simple, fast and cost effective urea combustion method for the first time and examined as novel material for supercapacitor.
MnIIand CuIIcomplexes with arylhydrazones of active methylene compounds as effective heterogeneous catalysts for solvent- and additive-free microwave-assisted peroxidative oxidation of alcohols
Authors: Mahmudov Kamran T. , Sutradhar Manas , Martins Luísa M. D. R. S. , Guedes da Silva M. Fátima C. , Ribera Alice , Nunes Ana V. M. , Gahramanova Shahnaz I. , Marchetti Fabio , Pombeiro Armando J. L.
Published: March 2015

Highly water-soluble MnIIand CuIIcomplexes are heterogeneous catalysts for solvent- and additive-free microwave-assisted peroxidative oxidation of less polar bulky substituted or long chain alcohols.
Increasing the rate of hydrogen oxidation without increasing the overpotential: a bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay
Authors: Darmon Jonathan M. , Kumar Neeraj , Hulley Elliott B. , Weiss Charles J. , Raugei Simone , Bullock R. Morris , Helm Monte L.
Published: March 2015

H2 oxidation by a molecular electrocatalyst is dramatically improved by controlling proton movement from iron to the outer coordination sphere.
In situ laser-imprinted surface realignment of a nematic liquid crystal
Authors: Mirri Giorgio , Škarabot Miha , Muševič Igor
Published: March 2015

We present a new method for the in-plane realignment of nematic liquid crystals in already fully assembled cells with uni-directionally rubbed polyimide as an aligning layer. This method can be applied to obtain twisted and planar μm-sized domains.
Facile preparation of an ultrathin sulfur-wrapped polyaniline nanofiber composite with a core–shell structure as a high performance cathode material for lithium–sulfur batteries
Authors: Gao Hong , Lu Qi , Liu Nianjiang , Wang Xianhong , Wang Fosong
Published: March 2015

An ultrathin sulfur-wrapped PANI nano-composite was well-designed and successfully prepared which displayed superior electrochemical performance.
Nanoengineered drug releasing aluminium wire implants: a model study for localized bone therapy
Authors: Rahman Shafiur , Atkins Gerald J. , Findlay David M. , Losic Dusan
Published: March 2015

A nanoengineered drug releasing aluminium wire implant has been developed and inserted into viable bone by a needle puncturing approach to directly deliver therapeutics inside the bone.
Bahl–Cocke–Jelinek–Raviv decoding algorithm applied to the three‐user binary adder channel
Authors: Alcoforado Maria de Lourdes M.G. , Oliveira Mariana C.C. , da Rocha Valdemar C.
Published: March 2015

The Bahl–Cocke–Jelinek–Raviv (BCJR) algorithm is a well‐known maximum a posteriori probability decoding algorithm which has been proposed earlier for point to point communication applications, employing block codes or convolutional codes and turbo codes. This study describes an application of the BCJR algorithm for decoding the output of a multiple‐access channel called the noisy three‐user binary adder channel, in the presence of additive white Gaussian noise. The computer simulation results are presented for the overall coding performance in terms of bit error rate against signal‐to‐noise ratio.
Colour image steganography method based on sparse representation
Authors: Ahani Soodeh , Ghaemmaghami Shahrokh
Published: March 2015

The authors address the use of sparse representation to securely hide a message within non‐overlapping blocks of a given colour image in the wavelet domain. All four sub‐images of the two‐dimensional wavelet transform of two colour bands are used for data embedding without affecting the image perceptibility. Bit error rate of hidden data extraction is reduced to zero by introducing a novel refinement procedure in the proposed algorithm. The refinement procedure introduced solves the hidden bit extraction errors caused by the rounding process, the overflows and the nature of approximation in sparse decomposition. Capacity of the proposed method is calculated using necessary conditions for uniqueness of the sparse representations and validated by means of experimental results. The authors experimental results show that the embedded data are invisible perceptually. The average peak signal‐to‐noise ratio (PSNR) value of the introduced method is about 40 and 11 dB higher than the average PSNR values of the MPSteg‐colour method and the wavelet domain 2‐LSB embedding method, respectively. The security of the proposed method is also evaluated comparatively, using five well‐known steganalysers, which confirms superior performance of the new method comparing with the MPSteg‐colour method and the wavelet domain 2‐LSB embedding method.
In Vitro Reconstitution of Metabolic Pathways: Insights into Nature’s Chemical Logic
Authors: Khosla Chaitan , Lowry Brian , Walsh Christopher
Published: March 2015

In vitro analysis of metabolic pathways is becoming a powerful method for gaining a deeper understanding of nature’s core biochemical transformations. Through the astounding advances in biotechnology, the purification of the enzymatic components of a given metabolic pathway is becoming a tractable problem; such in vitro studies permit scientists to capture the fine details of the mechanisms, kinetics, and identities of organic products of enzymatic reactions. In this review, we describe eleven metabolic pathways that have been the subject of recently reported in vitro reconstitution studies. In addition, we have selected and analyzed a subset of four case studies within these eleven examples that exemplify the remarkable organic chemistry that occurs within biological systems. These examples serves as tangible reminders that nature’s biochemical routes obey the fundamental principles of organic chemistry, as their chemical mechanisms are reminiscent of those occurring in conventional synthetic organic routes. The illustrations of biosynthetic chemistry presented in this review might inspire the development of biomimetic chemistries involving abiotic chemical techniques.

1 Introduction

2 Bacterial Metabolites

2.1 Fatty Acids

2.2 Farnesene

2.3 O-Polysaccharides

3 Plant Metabolites

3.1 Dhurrin

3.2 Camalexin

4 Polyketides and Nonribosomal Peptides

4.1 Aromatic Polyketides

4.1.1 Actinorhodin-Derived Polyketides

4.1.2 Enterocin

4.2 Fungal Polyketides

4.2.1 Norsolorinic Acid

4.2.2 Dihydromonacolin L

4.3 Assembly Line Polyketides and Nonribosomal Peptides

4.3.1 6-Deoxyerythronolide B

4.3.2 Asperlicin

5 Discussion of Chemical Insights

5.1 Allylic Carbocation Chemistry Drives Farnesene Synthesis

5.2 Multifunctional Oxidation Chemistry of Cytochrome P450 Enzymes

5.3 A Remarkable Favorskiiase Enzyme Within Enterocin Biosynthesis

5.4 Diels–Alder Chemistry Appears in Biology

6 Concluding Remarks
Concise Synthesis of (–)-Axenol by Using	Stereocontrolled Allylic Substitution
Authors: Kobayashi Yuichi , Ozaki Takuri
Published: March 2015

Synthesis of (–)-axenol was achieved stereoselectively through allylic substitution to form the quaternary carbon followed by ring-closing metathesis. The key allylic picolinate was synthesized from natural menthol.
Regioselective Hetero-Michael Addition of Oxygen, Sulfur, and Nitrogen­ Nucleophiles to Maleimides Catalyzed by BF3·OEt2
Authors: An Yu-Long , Deng Yun-Xia , Zhang Wei , Zhao Sheng-Yin
Published: March 2015

A practical BF3·OEt2-catalyzed regioselective 1,2-addition or 1,4-hetero-Michael addition of oxygen, sulfur, and nitrogen nucleo­philes to maleimides has been developed for the synthesis of alkyl fumarate derivatives or 3-substituted succinimides, respectively. This reaction system has wide substrate scope and gives moderate to excellent yields (up to 96%) of the desired products. In contrast to the base-catalyzed methods, this strategy is very general, simple, environmentally friendly, and tolerant of oxygen.
Custom Anatomical 3D Spacer for Temporomandibular Joint Resection and Reconstruction
Authors: Green JohnMarshall , Lawson Sarah T. , Liacouras Peter C. , Wise Edward M. , Gentile Michael A. , Grant GeraldThomas
Published: March 2015

Two cases are presented using a two-stage approach and a custom antibiotic spacer placement. Temporomandibular reconstruction can be very demanding and accomplished with a variety of methods in preparation of a total joint and ramus reconstruction with total joint prostheses (TMJ Concepts, Ventura, CA). Three-dimensional reconstructions from diagnostic computed tomography were used to establish a virtually planned resection which included the entire condyle-ramus complex. From these data, digital designs were used to manufacture molds to facilitate intraoperative fabrication of precise custom anatomic spacers from rapidly setting antibiotic-impregnated polymethyl methacrylate. Molds were manufactured using vat polymerization (stereolithography) with a photopolymer in the first case and powder bed fusion (electron beam melting) with Ti6AL4V for the second. Surgical methodology and the use of molds for intraoperative spacer fabrication for each case are discussed.
Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures
Authors: Ploetz Elizabeth A. , Smith Paul E.
Published: March 2015

Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations.
A fluorescence XAFS measurement instrument in the soft x-ray region toward observation under operando conditions
Authors: Honda M. , Baba Y. , Shimoyama I. , Sekiguchi T.
Published: March 2015

X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO42− when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.
Population transfer HMQC for half-integer quadrupolar nuclei
Authors: Wang Qiang , Li Yixuan , Trébosc Julien , Lafon Olivier , Xu Jun , Hu Bingwen , Feng Ningdong , Chen Qun , Amoureux Jean-Paul , Deng Feng
Published: March 2015

This work presents a detailed analysis of a recently proposed nuclear magnetic resonance method [Wang et al., Chem. Commun. 49(59), 6653-6655 (2013)] for accelerating heteronuclear coherence transfers involving half-integer spin quadrupolar nuclei by manipulating their satellite transitions. This method, called Population Transfer Heteronuclear Multiple Quantum Correlation (PT-HMQC), is investigated in details by combining theoretical analyses, numerical simulations, and experimental investigations. We find that compared to instant inversion or instant saturation, continuous saturation is the most practical strategy to accelerate coherence transfers on half-integer quadrupolar nuclei. We further demonstrate that this strategy is efficient to enhance the sensitivity of J-mediated heteronuclear correlation experiments between two half-integer quadrupolar isotopes (e.g., 27Al-17O). In this case, the build-up is strongly affected by relaxation for small T2′ and J coupling values, and shortening the mixing time makes a huge signal enhancement. Moreover, this concept of population transfer can also be applied to dipolar-mediated HMQC experiments. Indeed, on the AlPO4-14 sample, one still observes experimentally a 2-fold shortening of the optimum mixing time albeit with no significant signal gain in the 31P-{27Al} experiments.
Transition fields in organic materials: From percolation to inverted Marcus regime. A consistent Monte Carlo simulation in disordered PPV
Authors: Volpi Riccardo , Stafström Sven , Linares Mathieu
Published: March 2015

In this article, we analyze the electric field dependence of the hole mobility in disordered poly(p-phenylene vinylene). The charge carrier mobility is obtained from Monte Carlo simulations. Depending on the field strength three regions can be identified: the percolation region, the correlation region, and the inverted region. Each region is characterized by a different conduction mechanism and thus a different functional dependence of the mobility on the electric field. Earlier studies have highlighted that Poole-Frenkel law, which appears in the correlation region, is based on the type of correlation caused by randomly distributed electric dipoles. This behavior is thus observed in a limited range of field strengths, and by studying a broader range of electric fields, a more fundamental understanding of the transport mechanism is obtained. We identify the electric fields determining the transitions between the different conduction mechanisms in the material and we explain their physical origin. In principle, this allows us to characterize the mobility field dependence for any organic material. Additionally, we study the charge carrier trapping mechanisms due to diagonal and off-diagonal disorder, respectively.
The total position-spread tensor: Spin partition
Authors: El Khatib Muammar , Brea Oriana , Fertitta Edoardo , Bendazzoli Gian Luigi , Evangelisti Stefano , Leininger Thierry
Published: March 2015

The Total Position Spread (TPS) tensor, defined as the second moment cumulant of the position operator, is a key quantity to describe the mobility of electrons in a molecule or an extended system. In the present investigation, the partition of the TPS tensor according to spin variables is derived and discussed. It is shown that, while the spin-summed TPS gives information on charge mobility, the spin-partitioned TPS tensor becomes a powerful tool that provides information about spin fluctuations. The case of the hydrogen molecule is treated, both analytically, by using a 1s Slater-type orbital, and numerically, at Full Configuration Interaction (FCI) level with a V6Z basis set. It is found that, for very large inter-nuclear distances, the partitioned tensor growths quadratically with the distance in some of the low-lying electronic states. This fact is related to the presence of entanglement in the wave function. Non-dimerized open chains described by a model Hubbard Hamiltonian and linear hydrogen chains Hn (n ≥ 2), composed of equally spaced atoms, are also studied at FCI level. The hydrogen systems show the presence of marked maxima for the spin-summed TPS (corresponding to a high charge mobility) when the inter-nuclear distance is about 2 bohrs. This fact can be associated to the presence of a Mott transition occurring in this region. The spin-partitioned TPS tensor, on the other hand, has a quadratical growth at long distances, a fact that corresponds to the high spin mobility in a magnetic system.
A hybrid variational-perturbation calculation of the ro-vibrational spectrum of nitric acid
Authors: Pavlyuchko A. I. , Yurchenko S. N. , Tennyson Jonathan
Published: March 2015

Rotation-vibration spectra of the nitric acid molecule, HNO3, are calculated for wavenumbers up to 7000 cm−1. Calculations are performed using a Hamiltonian expressed in internal curvilinear vibrational coordinates employing a hybrid variational-perturbation method. An initial potential energy surface (PES) and dipole moment function (DMF) are calculated ab initio at the CCSD(T)/aug-cc-pVQZ level of theory. Parameters of the PES and DMF are varied to minimize differences between the calculated and experimental transition frequencies and intensities. The average, absolute deviation between calculated and experimental values is 0.2 cm−1 for frequencies in the fundamental bands and 0.4 cm−1 for those in the first overtone and lowest combination bands. For the intensities, the calculated and experimental values differ by 0.3% and 40% for the fundamentals and overtones, respectively. The optimized PES and DMF are used to calculate the room-temperature ro-vibrational spectrum. These calculation reproduce both the form of the absorption bands and fine details of the observed spectra, including the rotational structure of the vibrational bands and the numerous hot absorption band. Many of these hot bands are found to be missing from the compilation in HITRAN. A room temperature line list comprising 2 × 109 lines is computed.
On the validity of the basis set superposition error and complete basis set limit extrapolations for the binding energy of the formic acid dimer
Authors: Miliordos Evangelos , Xantheas Sotiris S.
Published: March 2015

We report the variation of the binding energy of the Formic Acid Dimer with the size of the basis set at the Coupled Cluster with iterative Singles, Doubles and perturbatively connected Triple replacements [CCSD(T)] level of theory, estimate the Complete Basis Set (CBS) limit, and examine the validity of the Basis Set Superposition Error (BSSE)-correction for this quantity that was previously challenged by Kalescky, Kraka, and Cremer (KKC) [J. Chem. Phys. 140, 084315 (2014)]. Our results indicate that the BSSE correction, including terms that account for the substantial geometry change of the monomers due to the formation of two strong hydrogen bonds in the dimer, is indeed valid for obtaining accurate estimates for the binding energy of this system as it exhibits the expected decrease with increasing basis set size. We attribute the discrepancy between our current results and those of KKC to their use of a valence basis set in conjunction with the correlation of all electrons (i.e., including the 1s of C and O). We further show that the use of a core-valence set in conjunction with all electron correlation converges faster to the CBS limit as the BSSE correction is less than half than the valence electron/valence basis set case. The uncorrected and BSSE-corrected binding energies were found to produce the same (within 0.1 kcal/mol) CBS limits. We obtain CCSD(T)/CBS best estimates for De = − 16.1 ± 0.1 kcal/mol and for D0 = − 14.3 ± 0.1 kcal/mol, the later in excellent agreement with the experimental value of −14.22 ± 0.12 kcal/mol.
Exchange biased magnetoelectric composites for magnetic field sensor application by frequency conversion
Authors: Röbisch V. , Yarar E. , Urs N. O. , Teliban I. , Knöchel R. , McCord J. , Quandt E. , Meyners D.
Published: March 2015

A comparison is presented between magnetoelectric composite sensors based on AlN and FeCoSiB with and without exchange bias coupling. All layer stacks were fabricated by thin film deposition on Si substrates. Whereas sensors without exchange bias exhibit a low limit of detection in the 1 pT/√Hz regime for resonant AC fields, such sensors fail at the detection of low frequency signals. Accordingly, their detection limit increases to about 10 nT/√Hz for alternating magnetic fields with 10 Hz frequency and an integration time equal to 3 s. A frequency conversion technique based on magnetic modulation of the sensors improves their detection limit by about one order of magnitude. However, frequency conversion can be applied more effectively to magnetoelectric sensors with exchange biased multilayers as a magnetostrictive phase. As a result, their limit of detection is about 180 pT/√Hz for 10 Hz signals and an integration time of 1 s. This is in contrast to the magnetoelectric coefficient αME of the two types of sensors. Whereas αME equals 6.9 kV/cm Oe for non-biased composites and resonant fields, it is by a factor of 8 smaller for the exchange biased composites. The nonetheless arising improvement of sensor performance with regard to the limit of detection for magnetic fields with low frequencies can be explained by a significantly lower magnetic noise contribution during modulation of the exchange biased sensors.
Magnetic response of aperiodic wire networks based on Fibonacci distortions of square antidot lattices
Authors: Farmer B. , Bhat V. S. , Sklenar J. , Teipel E. , Woods J. , Ketterson J. B. , Hastings J. T. , De Long L. E.
Published: March 2015

The static and dynamic magnetic responses of patterned ferromagnetic thin films are uniquely altered in the case of aperiodic patterns that retain long-range order (e.g., quasicrystals). We have fabricated permalloy wire networks based on periodic square antidot lattices (ADLs) distorted according to an aperiodic Fibonacci sequence applied to two lattice translations, d1 = 1618 nm and d2 = 1000 nm. The wire segment thickness is fixed at t = 25 nm, and the width W varies from 80 to 510 nm. We measured the DC magnetization between room temperature and 5 K. Room-temperature, narrow-band (9.7 GHz) ferromagnetic resonance (FMR) spectra were acquired for various directions of applied magnetic field. The DC magnetization curves exhibited pronounced step anomalies and plateaus that signal flux closure states. Although the Fibonacci distortion breaks the fourfold symmetry of a finite periodic square ADL, the FMR data exhibit fourfold rotational symmetry with respect to the applied DC magnetic field direction.
Enhanced flexoelectricity through residual ferroelectricity in barium strontium titanate
Authors: Garten Lauren M. , Trolier-McKinstry Susan
Published: March 2015

Residual ferroelectricity is observed in barium strontium titanate ceramics over 30 °C above the global phase transition temperature, in the same temperature range in which anomalously large flexoelectric coefficients are reported. The application of a strain gradient leads to strain gradient-induced poling or flexoelectric poling. This was observed by the development of a remanent polarization in flexoelectric measurements, an induced d33 piezoelectric response even after the strain gradient was removed, and the production of an internal bias of 9 kV m−1. It is concluded that residual ferroelectric response considerably enhances the observed flexoelectric response.
Modeling of particle agglomeration in nanofluids
Authors: Krishna K. Hari , Neti S. , Oztekin A. , Mohapatra S.
Published: March 2015

Agglomeration strongly influences the stability or shelf life of nanofluid. The present computational and experimental study investigates the rate of agglomeration quantitatively. Agglomeration in nanofluids is attributed to the net effect of various inter-particle interaction forces. For the nanofluid considered here, a net inter-particle force depends on the particle size, volume fraction, pH, and electrolyte concentration. A solution of the discretized and coupled population balance equations can yield particle sizes as a function of time. Nanofluid prepared here consists of alumina nanoparticles with the average particle size of 150 nm dispersed in de-ionized water. As the pH of the colloid was moved towards the isoelectric point of alumina nanofluids, the rate of increase of average particle size increased with time due to lower net positive charge on particles. The rate at which the average particle size is increased is predicted and measured for different electrolyte concentration and volume fraction. The higher rate of agglomeration is attributed to the decrease in the electrostatic double layer repulsion forces. The rate of agglomeration decreases due to increase in the size of nano-particle clusters thus approaching zero rate of agglomeration when all the clusters are nearly uniform in size. Predicted rates of agglomeration agree adequate enough with the measured values; validating the mathematical model and numerical approach is employed.
Is the Hénon attractor chaotic?
Authors: Galias Zbigniew , Tucker Warwick
Published: March 2015

By performing a systematic study of the Hénon map, we find low-period sinks for parameter values extremely close to the classical ones. This raises the question whether or not the well-known Hénon attractor—the attractor of the Hénon map existing for the classical parameter values—is a strange attractor, or simply a stable periodic orbit. Using results from our study, we conclude that even if the latter were true, it would be practically impossible to establish this by computing trajectories of the map.