bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid‐State Properties and Vibrational Circular Dichroism Spectroscopy in Solution of Hybrid Foldamers Stereoisomeric Mixtures
Authors: Castellucci Nicola , Falini Giuseppe , Milli Lorenzo , Monari Magda , Abbate Sergio , Longhi Giovanna , Castiglioni Ettore , Mazzeo Giuseppe , Tomasini Claudia 
Published: November 2013

AbstractUpon slow evaporation of a 1:1 diastereoisomeric mixture of Boc‐(L‐Phe‐L‐Oxd)2‐OBn (1; Boc=tert‐butyloxycarbonyl; L‐Oxd=trans‐(4S,5R)‐4‐carboxy 5‐methyloxazolidin‐2‐one, Bn=benzyloxycarbonyl) and Boc‐L‐Phe‐L‐Oxd‐D‐Phe‐L‐Oxd‐OBn (2) in methyl tert‐butyl ether, single crystals suitable for an X‐ray diffraction study were obtained. In contrast, the two pure oligomers lead to the formation of amorphous solids under any crystallization conditions. The preferential conformation of both oligomers was fully elucidated in the solid phase and compared with the known conformation of Boc‐(L‐Phe‐D‐Oxd)2‐OBn (3). The preferred conformation of 1 ranges from a polyproline II (PPII) helix to β strands and we can gather that longer and more structured oligomers will form PPII helices. In contrast, compound 3 forms infinite antiparallel β‐sheet structures; thus showing the strong effect of the reversal of the absolute configuration of the Oxd moieties on the secondary structure of these hybrid foldamers. The same outcome was retained in solution, as demonstrated by vibrational circular dichroism analysis. Finally, we have demonstrated that a 1:1 mixture of 1 and 2 leads to the formation of new materials with interesting properties that are missing from the two pure compounds, such as the tendency to form crystals, fibers, and globules, depending on the solvent.
Carbon Nitride for the Selective Oxidation of Aromatic Alcohols in Water under Visible Light
Authors: Long Baihua , Ding Zhengxin , Wang Xinchen 
Published: November 2013

AbstractThe front cover artwork for issue 11/2013 is provided by the group of Xincheng Wang at Fuzhou University (PR China). The image shows how a metal‐free carbon nitride photocatalyst selectively transforms aromatic alcohols into the corresponding aldehydes under visible light illumination. The Communication itself is available on page 2074.
Phylogenetic plant community structure along elevation is lineage specific
Authors: Ndiribe Charlotte , Pellissier Loïc , Antonelli Silvia , Dubuis Anne , Pottier Julien , Vittoz Pascal , Guisan Antoine , Salamin Nicolas 
Published: November 2013

AbstractThe trend of closely related taxa to retain similar environmental preferences mediated by inherited traits suggests that several patterns observed at the community scale originate from longer evolutionary processes. While the effects of phylogenetic relatedness have been previously studied within a single genus or family, lineage‐specific effects on the ecological processes governing community assembly have rarely been studied for entire communities or flora. Here, we measured how community phylogenetic structure varies across a wide elevation gradient for plant lineages represented by 35 families, using a co‐occurrence index and net relatedness index (NRI). We propose a framework that analyses each lineage separately and reveals the trend of ecological assembly at tree nodes. We found prevailing phylogenetic clustering for more ancient nodes and overdispersion in more recent tree nodes. Closely related species may thus rapidly evolve new environmental tolerances to radiate into distinct communities, while older lineages likely retain inherent environmental tolerances to occupy communities in similar environments, either through efficient dispersal mechanisms or the exclusion of older lineages with more divergent environmental tolerances. Our study illustrates the importance of disentangling the patterns of community assembly among lineages to better interpret the ecological role of traits. It also sheds light on studies reporting absence of phylogenetic signal, and opens new perspectives on the analysis of niche and trait conservatism across lineages.
Spectroscopic Studies and Crystal Structures of Double Thorium(IV) Oxalates with Sodium Ions
Authors: Zhang Yingjie , Bhadbhade Mohan , Karatchevtseva Inna , Gao Jiabin , Price Jason R. , Lumpkin Gregory R. 
Published: November 2013

AbstractTwo new double thorium oxalates with sodium ions have been prepared and characterized by using scanning electron microscopy/energy‐dispersive spectroscopy (SEM/EDS), Raman spectroscopy and single‐crystal X‐ray diffraction. The crystal structure of Na4[Th(C2O4)4]·5.5H2O (1) contains infinite chains, [Th(μ2‐C2O4)2(C2O4)3]n4n–, with three terminating bidentate and two bridging tetradentate oxalate ligands. The crystal structure of Na10[Th2(C2O4)9]·15H2O (2) comprises unique dimers, [Th2(μ2‐C2O4)(C2O4)8]10–, with Th atoms being coordinated by five oxalato ligands, four terminating bidentate and one bridging tetradentate. The structure is the first dimer of tetravalent actinide oxalato complexes. The spectroscopic results are in good agreement with the crystal structures.
Highlight Article summary: What are the trans fatty acids issues in foods after discontinuation of industrially produced trans fats? Ruminant products, vegetable oils, and synthetic supplements
Authors: Aldai Noelia , de Renobales Mertxe , Barron Luis Javier R. , Kramer John K.G. 
Published: November 2013

SUMMARYAdverse health effect of trans fatty acids (TFAs) are well recognized, which has precipitated efforts to reduce their content in food products. With the decline of dietary TFAs derived from partial oil hydrogenation, interest is focused on the remaining sources of dietary TFAs derived from ruminants (rTFA), deodorized vegetable oils, trans isomerization during frying, and synthetic conjugated FA (CFA) supplements. Partial hydrogenation and heat‐treated oils result in a random distribution of TFA isomers, whereas rTFAs contain specific isomers resulting from enzymatic processes. Reviews of human observational and metabolic intervention studies have suggested that consumption of rTFAs at current levels should not raise health concerns. However, these studies were not based on rTFA levels currently sold in retail markets. Current feeding practices of ruminants result in higher total TFAs with trans‐18:1 isomers other than vaccenic acid, and many CFAs other than rumenic acid. The definition of TFA adopted by several countries does not distinguish among isolated TFAs of concern and ignores CFAs that should be included in total TFA due to their negative health effects. Accurate TFA definition establishment and nutritional assessment of individual TFA isomers is needed for labeling purposes. Also required are adoptions of analytical methods to resolve all TFA isomers. This information can then be used to construct a database and as a basis for meaningful recommendations.Practical applications: Areas that require further investigations have been identified: 1) Establish a uniform TFA nomenclature based on chemical structure. 2) Standardize, assess and normalize appropriate methodologies for the analysis of TFAs. 3) Synthesize pure reference standards for TFA identification. 4) Report individual TFA levels with different biological activities rather than total TFA content. 5) Assess the nutritional characteristics of individual TFAs independent of their origin. 6) Develop strategies to increase the content of desirable TFA isomers in ruminants. 7) Identify potential bioactive trans metabolites produced from PUFAs in ruminants. 8) Develop labeling regulations based on specific chemical structures and physiological effects regardless of their origin. 9) Construct an accurate database complemented with specific surveys of ruminant product FA composition that can be accessed by regulatory agencies to make appropriate TFA recommendations.
Geophysical constraints on deep weathering and water storage potential in the Southern Sierra Critical Zone Observatory
Authors: Holbrook W. Steven , Riebe Clifford S. , Elwaseif Mehrez , L. Hayes Jorden , Basler‐Reeder Kyle , L. Harry Dennis , Malazian Armen , Dosseto Anthony , C. Hartsough Peter , W. Hopmans Jan 
Published: November 2013

ABSTRACTThe conversion of bedrock to regolith marks the inception of critical zone processes, but the factors that regulate it remain poorly understood. Although the thickness and degree of weathering of regolith are widely thought to be important regulators of the development of regolith and its water‐storage potential, the functional relationships between regolith properties and the processes that generate it remain poorly documented. This is due in part to the fact that regolith is difficult to characterize by direct observations over the broad scales needed for process‐based understanding of the critical zone. Here we use seismic refraction and resistivity imaging techniques to estimate variations in regolith thickness and porosity across a forested slope and swampy meadow in the Southern Sierra Critical Zone Observatory (SSCZO). Inferred seismic velocities and electrical resistivities image a weathering zone ranging in thickness from 10 to 35 m (average = 23 m) along one intensively studied transect. The inferred weathering zone consists of roughly equal thicknesses of saprolite (P‐velocity < 2 km s−1) and moderately weathered bedrock (P‐velocity = 2–4 km s−1). A minimum‐porosity model assuming dry pore space shows porosities as high as 50% near the surface, decreasing to near zero at the base of weathered rock. Physical properties of saprolite samples from hand augering and push cores are consistent with our rock physics model when variations in pore saturation are taken into account. Our results indicate that saprolite is a crucial reservoir of water, potentially storing an average of 3 m3 m−2 of water along a forested slope in the headwaters of the SSCZO. When coupled with published erosion rates from cosmogenic nuclides, our geophysical estimates of weathering zone thickness imply regolith residence times on the order of 105 years. Thus, soils at the surface today may integrate weathering over glacial–interglacial fluctuations in climate. Copyright © 2013 John Wiley & Sons, Ltd.
Characterization of retinoic acid–induced neurobehavioral effects in developing zebrafish
Authors: Wang Yujiang , Chen Jiangfei , Du Changchun , Li Chunqi , Huang Changjiang , Dong Qiaoxiang 
Published: November 2013

Abstract

Retinoic signaling plays an important role in cell proliferation and differentiation. Disruption of retinoic signaling via excessive or deficient retinoic acid can cause teratogenic effects on developing embryos. Similar to retinoic acid, many xenobiotic environmental pollutants have been found to disrupt retinoic signaling through binding and eliciting agonistic activity on retinoic acid receptors. Currently, studies of retinoic acid or retinoic acid–like compounds in aquatic organisms have mainly focused on teratogenicity and few studies have explored their neurobehavioral toxicity. In the present study, the authors used retinoic acid as an example to explore the neurobehavioral toxicity associated with developmental exposure of retinoic acid–like compounds in zebrafish. The findings confirmed retinoic acid's teratogenic effects such as bent spine, malformed tail, and pericardial edema in developing zebrafish with a median effective concentration of 2.47 nM. Retinoic acid–induced cell apoptosis at 24 h postfertilization was consistently found in the eye and tail regions of embryos. Spontaneous movement as characterized by tail bend frequency was significantly increased in zebrafish embryos following exposure to 2 nM and 8 nM retinoic acid. Relatively low-dose retinoic acid exposure of 2 nM led to fast locomotion behavior in the dark period and hyperactivity during light–dark photoperiod stimulation. The 2-nM retinoic acid exposure also led to alterations of neurobehavior- and optic nerve–related genes, with the transforming growth factor-β signal transduction inhibitor noggin (nog) and the spinal cord marker homeobox c3a (hox) being underexpressed and the retinal G protein–coupled receptor a (rgr), the photoreceptor cell marker rhodopsin (rho), and the short wave–sensitive cone pigment opsin 1 (opn1sw1) being overexpressed. Increased expression of opn1sw1 and rho was confirmed by whole-mount in situ hybridization. Whether the misexpression of these genes leads to the neurobehavioral changes merits further study. The findings demonstrated that low-dose retinoic acid exposure perturbed the visual system and optic nerve development and caused hyperactivity in developing zebrafish. Environ Toxicol Chem 2014;33:431–437. © 2013 SETAC
Spectroscopic biofeedback on cutaneous carotenoids as part of a prevention program could be effective to raise health awareness in adolescents
Authors: Yu Ruo‐Xi , Köcher Wolfgang , Darvin Maxim E. , Büttner Monika , Jung Sora , Lee Bich Na , Klotter Christoph , Hurrelmann Klaus , Meinke Martina C. , Lademann Jürgen 
Published: November 2013

AbstractThe cutaneous carotenoid concentration correlates with the overall antioxidant status of a person and can be seen as biomarker for nutrition and lifestyle. 50 high school students were spectroscopically measured for their cutaneous carotenoid concentrations initially in a static phase, followed by an intervention phase with biofeedback of their measured values, living a healthy lifestyle and on healthy food this time. The volunteers showed higher carotenoid concentrations than found in previous studies. A significant correlation of healthy lifestyle habits and a high antioxidant status could be determined. Subjects improved their nutritional habits and significantly increased their carotenoid concentration during intervention. Follow‐up five months later showed a consolidation of the increase. The investigations show that a healthy diet and a well‐balanced lifestyle correlate with a high cutaneous antioxidant concentration and that spectroscopic biofeedback measurement of cutaneous carotenoids as part of an integrated prevention program is a feasible and effective means to raise the health awareness in adolescents. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Arctigenin Enhances Chemosensitivity to Cisplatin in Human Nonsmall Lung Cancer H460 Cells through Downregulation of Survivin Expression
Authors: Wang Huan‐qin , Jin Jian‐jun , Wang Jing 
Published: November 2013

ABSTRACTArctigenin, a dibenzylbutyrolactone lignan, enhances cisplatin‐mediated cell apoptosis in cancer cells. Here, we sought to investigate the effects of arctigenin on cisplatin‐treated non‐small‐cell lung cancer (NSCLC) H460 cells. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and annexin‐V/propidium iodide staining were performed to analyze the proliferation and apoptosis of H460 cells. Arctigenin dose‐dependently suppressed cell proliferation and potentiated cell apoptosis, coupled with increased cleavage of caspase‐3 and poly(ADP‐ribose) polymerase. Moreover, arctigenin sensitized H460 cells to cisplatin‐induced proliferation inhibition and apoptosis. Arctigenin alone or in combination with cisplatin had a significantly lower amount of survivin. Ectopic expression of survivin decreased cell apoptosis induced by arctigenin (P < 0.05) or in combination with cisplatin (P < 0.01). Moreover, arctigenin (P < 0.05) or in combination with cisplatin (P < 0.01) induced G1/G0 cell‐cycle arrest. Our data provide evidence that arctigenin has a therapeutic potential in combina‐tion with chemotherapeutic agents for NSLC.
Chemoselective Synthesis of β‐Amino Ester or β‐Lactam via Sonochemical Reformatsky Reaction
Authors: Lee Adam Shih‐Yuan , Chang Yu‐Ting , Su Feng‐Yi 
Published: November 2013

AbstractA series of β‐amino esters were synthesized by the reaction of N‐tosyl aldimine or N‐hydroxy aldimine with bromoacetate by sonochemical Reformatsky reaction. The β‐N‐hydroxyamino ester was obtained and the formed sensitive hydroxylamino functionality was resistant under the reaction condition. The β‐lactam also was synthesized by the reaction of N‐p‐methoxy aldimine as reacting substrate under this sonochemical Reformatsky reaction condition.
An Efficient One‐pot Access to Substituted Dihydropyrrol‐2‐one Derivatives Using Sucrose as Natural, Biodegradable and Inexpensive Catalyst
Authors: Hazeri Nourallah , Sajadikhah Seyed Sajad , Maghsoodlou Malek Taher , Mohamadian‐Souri Sajad , Norouzi Mahmoud , Moein Maryam 
Published: November 2013

AbstractAn efficient and simple procedure for the synthesis of highly substituted dihydropyrrol‐2‐ones has been developed via one‐pot four‐component condensation of amines, dialkyl acetylenedicarboxyaltes and formaldehyde in the presence of sucrose as an organocatalyst. The salient advantages of this method are using a natural, biodegradable and commercial available catalyst, good yields, short reaction times, simple work‐up and lack of need for column chromatography.
Synthesis of Phosphatidylinositol Mannosides
Authors: Patil Pratap S. , Zulueta Medel Manuel L. , Hung Shang‐Cheng 
Published: November 2013

AbstractThe cell envelope of mycobacterial species, which include the deadly Mycobacterium tuberculosis, carries unique glycan structures that are crucial for infection and bacterial survival. Notable among these glycans are the structurally‐related phosphatidylinositol mannosides (PIMs), lipomannan, and lipoarabinomannan. The immunoactivities of these structures attracted considerable attention from synthetic chemists and biologists alike, who are keen on evaluating vaccine or adjuvant properties. Moreover, PIMs are interesting synthetic targets because of the regio‐ and stereoselective considerations in generating the inositol and mannosyl cores. In this paper, we summarize the recent efforts in the chemical synthesis of PIMs as well as their analogues. Particular emphasis is given on the challenges associated with the preparation of the chiral myo‐inositol derivatives, the regioselective installation of mannosyl residues, and phosphatidylation strategies. The results of the bioevaluation of selected compounds are also briefly described.
Development and validation of a novel method to derive central aortic systolic pressure from the MR aortic distension curve
Authors: Quail Michael A. , Steeden Jennifer A. , Knight Daniel , Segers Patrick , Taylor Andrew M. , Muthurangu Vivek 
Published: November 2013

PurposeCentral aortic systolic pressure (CASP) is a more accurate measure of load and cardiovascular risk than brachial pressure. Unfortunately, CASP is difficult to measure using current methods. In this study we report three methods of determining CASP by combining MR‐derived aortic area curves with different models of the pressure–area relationship.Materials and MethodsCASP was derived by calibrating aortic area curves to the brachial mean and diastolic pressure, using: linear, exponential, and arctangent models in 20 volunteers using a high temporal resolution spiral PC‐MR flow sequence. The arctangent model also required calibration with pulse wave velocity. Carotid tonometry CASP was used as the reference standard.ResultsBrachial systolic pressure correlated only moderately with carotid CASP r2 = 0.46 (P = 0.01). However, arctangent, exponential, and linear CASP correlated strongly with carotid CASP, r2 = 0.90, r2 = 0.86, r2 = 0.85, respectively (P < 0.0001). There was excellent agreement between carotid CASP and both arctangent (bias 1.5; SD 3.3) and exponential CASP (bias 0.6; SD 3.6). There was a slight underestimation using the linear model (bias −2.3; SD 3.8) and poor agreement and overestimation using brachial systolic pressure (bias 12.9; SD 8.0).ConclusionWe have shown that CASP can be derived from MR data: arctangent and exponential methods being superior to the linear method. The superior correlation of MR derived CASP over brachial systolic BP suggests these measures will allow more comprehensive assessment of systemic arterial hypertension.J. Magn. Reson. Imaging 2014;40:1064–1070. © 2013 Wiley Periodicals, Inc.
Quantification of cerebral blood flow in healthy volunteers and type 1 diabetic patients: Comparison of MRI arterial spin labeling and [15O]H2O positron emission tomography (PET)
Authors: van Golen Larissa W. , Kuijer Joost P.A. , Huisman Marc C. , IJzerman Richard G. , Barkhof Frederik , Diamant Michaela , Lammertsma Adriaan A. 
Published: November 2013

PurposeTo compare cerebral blood flow (CBF) values measured using magnetic resonance imaging (MRI) arterial spin labeling (ASL) with those obtained with [15O]H2O positron emission tomography (PET), the gold standard for measuring CBF in vivo.Materials and MethodsData were collected in 11 healthy men and in 20 age‐ and body mass index (BMI)‐matched type 1 diabetic men. Pseudo‐continuous ASL (PCASL) data were acquired at 3 T and [15O]H2O PET scans were acquired using a high‐resolution PET scanner. Input functions were obtained using on‐line arterial blood sampling. Whole brain and regional CBF values were compared.ResultsFor both modalities, whole brain CBF was similar in both subject groups. In groups combined, average whole brain CBF was 0.30 ± 0.05 mL·cm−3·min−1 for [15O]H2O PET and 0.34 ± 0.05 mL·cm−3·min−1 for ASL MRI (P < 0.01). A significant correlation between methods was observed for whole brain, gray and white matter. In 12 out of 33 brain regions a significant difference between methods was observed.ConclusionPCASL provides CBF values that correlate with [15O]H2O PET‐derived values, but is less accurate. PCASL may be an attractive alternative when absolute quantification is not needed.J. Magn. Reson. Imaging 2014;40:1300–1309. © 2013 Wiley Periodicals, Inc.
Quantitative assessment of susceptibility‐weighted imaging processing methods
Authors: Li Ningzhi , Wang Wen‐Tung , Sati Pascal , Pham Dzung L. , Butman John A. 
Published: November 2013

PurposeTo evaluate different susceptibility‐weighted imaging (SWI) phase processing methods and parameter selection, thereby improving understanding of potential artifacts, as well as facilitating choice of methodology in clinical settings.Materials and MethodsTwo major phase processing methods, homodyne‐filtering and phase unwrapping‐high pass (HP) filtering, were investigated with various phase unwrapping approaches, filter sizes, and filter types. Magnitude and phase images were acquired from a healthy subject and brain injury patients on a 3T clinical Siemens MRI system. The results were evaluated based on image contrast‐to‐noise ratio and presence of processing artifacts.ResultsWhen using a relatively small filter size (32 pixels for the matrix size 512 × 512 pixels), all homodyne‐filtering methods were subject to phase errors leading to 2% to 3% masked brain area in lower and middle axial slices. All phase unwrapping‐filtering/smoothing approaches demonstrated fewer phase errors and artifacts compared to the homodyne‐filtering approaches. For performing phase unwrapping, Fourier‐based methods, although less accurate, were 2–4 orders of magnitude faster than the PRELUDE, Goldstein, and Quality‐guide methods.ConclusionAlthough homodyne‐filtering approaches are faster and more straightforward, phase unwrapping followed by HP filtering approaches perform more accurately in a wider variety of acquisition scenarios. J. Magn. Reson. Imaging 2014;40:1463–1473. © 2013 Wiley Periodicals, Inc.
Efficient Separation of Conjugated Polymers Using a Water Soluble Glycoprotein Matrix: From Fluorescence Materials to Light Emitting Devices
Authors: Hendler Netta , Wildeman Jurjen , Mentovich Elad. D. , Schnitzler Tobias , Belgorodsky Bogdan , Prusty Deepak K. , Rimmerman Dolev , Herrmann Andreas , Richter Shachar 
Published: November 2013

AbstractOptically active bio‐composite blends of conjugated polymers or oligomers are fabricated by complexing them with bovine submaxilliary mucin (BSM) protein. The BSM matrix is exploited to host hydrophobic extended conjugated π‐systems and to prevent undesirable aggregation and render such materials water soluble. This method allows tuning the emission color of solutions and films from the basic colors to the technologically challenging white emission. Furthermore, electrically driven light emitting biological devices are prepared and operated.