bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of High‐Mannose Oligosaccharide Analogues through Click Chemistry: True Functional Mimics of Their Natural Counterparts Against Lectins?
Authors: François‐Heude Marc , Méndez‐Ardoy Alejandro , Cendret Virginie , Lafite Pierre , Daniellou Richard , Ortiz Mellet Carmen , García Fernández José M. , Moreau Vincent , Djedaïni‐Pilard Florence 
Published: December 2014

AbstractTerminal “high‐mannose oligosaccharides” are involved in a broad range of biological and pathological processes, from sperm‐egg fusion to influenza and human immunodeficiency virus infections. In spite of many efforts, their synthesis continues to be very challenging and actually represents a major bottleneck in the field. Whereas multivalent presentation of mannopyranosyl motifs onto a variety of scaffolds has proven to be a successful way to interfere in recognition processes involving high‐mannose oligosaccharides, such constructs fail at reproducing the subtle differences in affinity towards the variety of protein receptors (lectins) and antibodies susceptible to binding to the natural ligands. Here we report a family of functional high‐mannose oligosaccharide mimics that reproduce not only the terminal mannopyranosyl display, but also the core structure and the branching pattern, by replacing some inner mannopyranosyl units with triazole rings. Such molecular design can be implemented by exploiting “click” ligation strategies, resulting in a substantial reduction of synthetic cost. The binding affinities of the new “click” high‐mannose oligosaccharide mimics towards two mannose specific lectins, namely the plant lectin concanavalin A (ConA) and the human macrophage mannose receptor (rhMMR), have been studied by enzyme‐linked lectin assays and found to follow identical trends to those observed for the natural oligosaccharide counterparts. Calorimetric determinations against ConA, and X‐ray structural data support the conclusion that these compounds are not just another family of multivalent mannosides, but real “structural mimics” of the high‐mannose oligosaccharides.
Ru‐Catalyzed Decarboxylative Annulations of α‐Keto Acids with Internal Alkynes: Dual Roles of COOH as Directing Group and Leaving Group
Authors: Tan Hui , Li Hongji , Wang Jiawang , Wang Lei 
Published: December 2014

AbstractCarboxylic acid serving as both directing and leaving group was discovered in Ru‐catalyzed decarboxylative annulations of α‐keto acids with alkynes. The well‐established protocol showed high functional group tolerance, which provided an efficient and alternative route to the coumarone backbone.
Replacement of Water Molecules in a Phosphate Binding Site by Furanoside‐Appended lin‐Benzoguanine Ligands of tRNA‐Guanine Transglycosylase (TGT)
Authors: Barandun Luzi J. , Ehrmann Frederik R. , Zimmerli Daniel , Immekus Florian , Giroud Maude , Grünenfelder Claudio , Schweizer W. Bernd , Bernet Bruno , Betz Michael , Heine Andreas , Klebe Gerhard , Diederich François 
Published: December 2014

AbstractThe enzyme tRNA‐guanine transglycosylase has been identified as a drug target for the foodborne illness shigellosis. A key challenge in structure‐based design for this enzyme is the filling of the polar ribose‐34 pocket. Herein, we describe a novel series of ligands consisting of furanoside‐appended lin‐benzoguanines. They were designed to replace a conserved water cluster and differ by the functional groups at C(2) and C(3) of the furanosyl moiety being either OH or OMe. The unfavorable desolvation of Asp102 and Asp280, which are located close to the ribose‐34 pocket, had a significant impact on binding affinity. While the enzyme has tRNA as its natural substrate, X‐ray co‐crystal structures revealed that the furanosyl moieties of the ligands are not accommodated in the tRNA ribose‐34 site, but at the location of the adjacent phosphate group. A remarkable similarity of the position of the oxygen atoms in these two structures suggests furanosides as a potential phosphate isoster.
Unprecedented Oxidative Addition and Metal‐Only Lewis Pair Chemistry of Antimony Trihalides
Authors: Braunschweig Holger , Dewhurst Rian D. , Hupp Florian , Wolf Justin 
Published: December 2014

AbstractReaction of the zero‐valent platinum complex [Pt(PCy3)2] with SbF3 generates the cationic diplatinum stibenium complex [{(Cy3P)2Pt}2(μ‐SbF2)]+, the first unsupported metal‐only Lewis pair containing an antimony‐centered Lewis acid. In contrast, SbCl3 undergoes oxidative addition to [Pt(PCy3)2], resulting in the dihalostibanyl complex trans‐[PtCl(SbCl2)(PCy3)2], the first example of oxidative addition of an antimony–halide bond to a transition metal.
Brønsted Acid‐Catalyzed, Highly Enantioselective Addition of Enamides to In Situ‐Generated ortho‐Quinone Methides: A Domino Approach to Complex Acetamidotetrahydroxanthenes
Authors: Saha Satyajit , Schneider Christoph 
Published: December 2014

AbstractThe highly enantioselective conjugate addition of enamides and enecarbamates to in situ‐generated ortho‐quinone methides, upon subsequent N,O‐acetalization, gives rise to acetamido‐substituted tetrahydroxanthenes with generally excellent enantio‐ and diastereoselectivities. A chiral BINOL‐based phosphoric acid catalyst controls the enantioselectivity of the carbon–carbon bond‐forming event. The products are readily converted into other xanthene‐based heterocycles.
Combination of Solid‐Phase Micro‐Extraction and Direct Analysis in Real Time‐Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages
Authors: Wu Mengxi , Wang Haoyang , Dong Guoqing , Musselman Brian D. , Liu Charles C. , Guo Yinlong 
Published: December 2014

AbstractA method for rapid identification and quantification of phthalate plasticizers in beverages was developed. A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act (CPSIA), European Union legislations and Chinese national standards (GB) were analyzed. By a combined solid‐phase micro‐extraction (SPME) and direct analysis in real time mass spectrometry (DART‐MS) approach, phthalates at sub‐ng·mL−1 levels can be qualitatively and quantitatively analyzed in a short time. The use of ultrahigh‐resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS) minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations. The limits of quantification (LOQs) were estimated to be at 0.3–5.0 ng·mL−1, lower than the Maximum Residue Limit (MRL) regulated by the European Union legislations (2007/19/EC) in foods, beverages, food packaging and toys (0.3–30 ng·mL−1). This rapid and easy‐to‐use SPME‐DART‐FT‐ICR‐MS method provided a relatively high‐throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.
Merging Allosteric and Active Site Binding Motifs: De novo Generation of Target Selectivity and Potency via Natural‐Product‐Derived Fragments
Authors: Lanz Jan , Riedl Rainer 
Published: December 2014

AbstractThe de novo design of molecules from scratch with tailored biological activity is still the major intellectual challenge in chemical biology and drug discovery. Herein we validate natural‐product‐derived fragments (NPDFs) as excellent molecular seeds for the targeted de novo discovery of lead structures for the modulation of therapeutically relevant proteins. The application of this de novo approach delivered, in synergy with the combination of allosteric and active site binding motifs, highly selective and ligand‐efficient non‐zinc‐binding (3: 4‐{[5‐(2‐{[(3‐methoxyphenyl)methyl]carbamoyl}eth‐1‐yn‐1‐yl)‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl]methyl}benzoic acid) as well as zinc‐binding (4: 4‐({5‐[2‐({[3‐(3‐carboxypropoxy)phenyl]methyl}carbamoyl)eth‐1‐yn‐1‐yl]‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl}methyl)benzoic acid) uracil‐based MMP‐13 inhibitors presenting IC50 values of 11 nM (3: LE=0.35) and 6 nM (4: LE=0.31).
Neoadjuvant gemcitabine, docetaxel, and capecitabine followed by gemcitabine and capecitabine/radiation therapy and surgery in locally advanced, unresectable pancreatic adenocarcinoma
Authors: Sherman William H. , Chu Kyung , Chabot John , Allendorf John , Schrope Beth Ann , Hecht Elizabeth , Jin Brian , Leung David , Remotti Helen , Addeo Gisella , Postolov Inna , Tsai Wei , Fine Robert L. 
Published: December 2014

BACKGROUNDThis prospective study was undertaken to assess toxicity, resectability, and survival in pancreatic adenocarcinoma patients presenting with locally advanced, unresectable disease treated with neoadjuvant gemcitabine, docetaxel, and capecitabine (GTX) and gemcitabine and capecitabine (GX)/radiation therapy (RT).METHODSAll patients presenting to the Pancreas Center were evaluated for eligibility. Forty‐five patients (mean age, 64 years; range, 44‐83 years)—34 patients deemed unresectable because of arterial involvement and 11 patients deemed unresectable because of extensive venous involvement—were treated with 6 cycles of GTX. Those with arterial involvement were treated with GX/RT after chemotherapy.RESULTSThe GTX and GX/RT treatments were tolerated with the expected drug‐related toxicities. There were no bowel perforations, cases of pancreatitis, or delayed strictures. Among those with arterial involvement, 29 underwent subsequent resection, with 20 (69%) achieving R0 resections. All 11 patients with venous‐only involvement underwent resection, with 8 achieving R0 resections and 3 achieving complete pathologic responses. For the arterial arm, the 1‐year survival rate was 71% (24 of 34 patients), and the median survival was 29 months (95% confidence interval, 21‐38 months). Thirteen patients (38%) have not relapsed (range, 5‐49+ months). For the venous arm, the median survival has not been reached at more than 42 months. Six patients (55%) in the venous arm did not experience recurrence (range, 6.2‐42+ months).CONCLUSIONSGTX plus GX/RT is an effective neoadjuvant regimen that can be safely administered to patients up to at least the age of 83 years. It is associated with a high response rate, a high rate of R0 resections, and prolonged overall survival. Cancer 2015;121:673–680. © 2014 American Cancer Society.
Photoelectron Circular Dichroism of Bicyclic Ketones from Multiphoton Ionization with Femtosecond Laser Pulses
Authors: Lux Christian , Wollenhaupt Matthias , Sarpe Cristian , Baumert Thomas 
Published: December 2014

AbstractPhotoelectron circular dichroism (PECD) is a CD effect up to the ten‐percent regime and shows contributions from higher‐order Legendre polynomials when multiphoton ionization is compared to single‐photon ionization. We give a full account of our experimental methodology for measuring the multiphoton PECD and derive quantitative measures that we apply on camphor, fenchone and norcamphor. Different modulations and amplitudes of the contributing Legendre polynomials are observed despite the similarity in chemical structure. In addition, we study PECD for elliptically polarized light employing tomographic reconstruction methods. Intensity studies reveal dissociative ionization as the origin of the observed PECD effect, whereas ionization of the intermediate resonance is dominating the signal. As a perspective, we suggest to make use of our tomographic data as an experimental basis for a complete photoionization experiment and give a prospect of PECD as an analytic tool.
Diazo Compounds in Continuous‐Flow Technology
Authors: Müller Simon T. R. , Wirth Thomas 
Published: December 2014

AbstractDiazo compounds are very versatile reagents in organic chemistry and meet the challenge of selective assembly of structurally complex molecules. Their leaving group is dinitrogen; therefore, they are very clean and atom‐efficient reagents. However, diazo compounds are potentially explosive and extremely difficult to handle on an industrial scale. In this review, it is discussed how continuous flow technology can help to make these powerful reagents accessible on large scale. Microstructured devices can improve heat transfer greatly and help with the handling of dangerous reagents safely. The in situ formation and subsequent consumption of diazo compounds are discussed along with advances in handling diazomethane and ethyl diazoacetate. The potential large‐scale applications of a given methodology is emphasized.
Enhancing the Stability of Porphyrin Dye‐Sensitized Solar Cells by Manipulation of Electrolyte Additives
Authors: Lau Genevieve P. S. , Tsao Hoi Nok , Yi Chenyi , Zakeeruddin Shaik M. , Grätzel Michael , Dyson Paul J. 
Published: December 2014

AbstractThe use of porphyrin‐based photosensitizers with superior light‐harvesting properties has enabled the power conversion efficiency of dye‐sensitized solar cells (DSCs) to reach 13 % under full sun illumination. However, a major limitation of such devices corresponds to the volatility of the solvent used so far for the electrolyte, which prevents practical applications. In this work, we describe a porphyrin‐ionic liquid DSC, which not only affords the highest efficiency reported to date, but is also stable for more than 300 h under continuous full sun illumination at 60 °C. Furthermore, we identify a previously unreported pathway for device degradation, and show that the addition of N‐methylbenzimidazole and a thiocyanate salt to the electrolyte is critical to obtaining long‐lived devices.
Image based validation of dynamical models for cell reorientation
Authors: Lockley Robert , Ladds Graham , Bretschneider Till 
Published: December 2014

AbstractA key feature of directed cell movement is the ability of cells to reorient quickly in response to changes in the direction of an extracellular stimulus. Mathematical models have suggested quite different regulatory mechanisms to explain reorientation, raising the question of how we can validate these models in a rigorous way. In this study, we fit three reaction–diffusion models to experimental data of Dictyostelium amoebae reorienting in response to alternating gradients of mechanical shear flow. The experimental readouts we use to fit are spatio‐temporal distributions of a fluorescent reporter for cortical F‐actin labeling the cell front. Experiments performed under different conditions are fitted simultaneously to challenge the models with different types of cellular dynamics. Although the model proposed by Otsuji is unable to provide a satisfactory fit, those suggested by Meinhardt and Levchenko fit equally well. Further, we show that reduction of the three‐variable Meinhardt model to a two‐variable model also provides an excellent fit, but has the advantage of all parameters being uniquely identifiable. Our work demonstrates that model selection and identifiability analysis, commonly applied to temporal dynamics problems in systems biology, can be a powerful tool when extended to spatio‐temporal imaging data. © 2014 The Authors. Published by Wiley Periodicals, Inc.
Peak‐to‐average power ratio reduction of a hidden training sequence‐aided precoding scheme for MIMO‐OFDM
Authors: Kim Byung Wook , Jung Sung‐Yoon 
Published: December 2014

SummaryWe analyze a peak‐to‐average power ratio (PAPR) reduction property based on a hidden training sequence‐aided precoding scheme for MIMO‐OFDM systems. In addition to the benefits of a hidden training sequence‐aided precoding scheme such as improvement in bandwidth efficiency and frequency diversity gain, we address that power amplifier efficiency can be improved without any additional complexity burden. By mathematically analyzing PAPR of the precoded MIMO‐OFDM signal with a hidden training sequence, we demonstrate that PAPR reduction can be obtained by varying the allocated power to the hidden training sequence. Because of the low PAPR property of this scheme, it is possible to utilize a low‐cost power amplifier, resulting in the reduction in the total cost for hardware implementation. Copyright © 2014 John Wiley & Sons, Ltd.
The use of urinary nuclear matrix protein 22 (NMP22) as a diagnostic adjunct to urine cytology for monitoring of recurrent bladder cancer—institutional experience and review
Authors: Önal Binnur , Han Ünsal , Yilmaz Sinasi , Köybasioglu Fulya , Altuğ Uğur 
Published: December 2014

BackgroundThis prospective study compares urine NMP22 immunoassay and cytomorphology for detecting recurrent urothelial carcinoma (UC) of the bladder and correlates between NMP22 levels and grade, multiplicity, and size of the tumor. We aimed refining the use of NMP22 test in the management of UC at our institution.MethodsUrine specimens, collected prior to a cystoscopic biopsy either from patients with a history of bladder cancer (n = 50) or from controls (n = 15) were studied. Cytology and NMP22 results were compared with subsequent biopsies and performance characteristics were measured.ResultsOverall sensitivity and specificity of cytology was 62.5% and 87.5%, respectively while NMP22 had a sensitivity of 85.4% and specificity of 76.5%. NMP22 was superior to cytology for detecting low‐grade UC (82.6% vs. 54.5%) and in terms of NPV (65% vs. 44.4%) while cytology reached 100% detection rate for high‐grade UC. And, the sensitivity of 98% was achieved when NMP22 was combined with atypical cytology. Optimal performance of NMP22 has been detected around the reference value of 6.4 U/ml. The mean NMP22 values in control and study groups were 2.5 U/ml and 36 U/ml, respectively. The mean NMP22 value was 20.9 U/ml in low‐grade UC and 53.2 U/ml in high‐grade category.ConclusionsThe NMP22 values displayed higher sensitivity for low‐grade UC while cytology was highly sensitive and spesific in detection of high‐grade UC. Combining urine NMP22 assay with atypical cytology improved sensitivity for detection of recurrent UC. The inclusion of the adjunctive NMP22 test in monitoring protocols for low‐grade UC in combination with cytology for high‐grade UC could enable clinicians to decrease the frequency of follow‐up cystoscopies. Diagn. Cytopathol. 2015;43:307–314. © 2014 Wiley Periodicals, Inc.
Habitat selection and consumption across a landscape of multiple predators
Authors: Wesner Jeff S. , Meyers Peter , Billman Eric J. , Belk Mark C. 
Published: December 2014

AbstractPredator community composition can alter habitat quality for prey by changing the strength and direction of consumptive effects. Whether predator community composition also alters prey density via nonconsumptive effects during habitat selection is not well known, but is important for understanding how changes to predator communities will alter prey populations. We tested the hypothesis that predator community composition (presence of caged trout, caged dragonflies, or caged trout + dragonflies) alters colonization of aquatic mesocosms by ovipositing aquatic insects. In a previous experiment in this system, we found a spatial contagion effect, in which insects avoided pools with predators, but only when predator‐free pools were isolated (~5 m away from predator pools). Here, we removed the isolated predator‐free pools, allowing us to test whether insects would make fine‐scale (~1 m) oviposition decisions in the absence of preferred isolated pools. We also estimated consumptive effects by allowing predators to feed on colonists for 5 days following colonization. All insects collected after 21 days were dipterans, dominated by Chironomidae. Total colonization, measured as the number of developing larvae after 21 days, was not affected by either predator presence or composition. Consumption was significant in the trout only treatment, reducing larval insect density by 46 ± 37% (mean ± SE). No other predator treatment significantly reduced prey density, although the proportion of chironomid larvae in protective cases increased in response to direct predation from dragonflies, indicating an antipredatory behavioral response. Taken together, these results reveal that predator community composition altered larval survival and behavior, but colonizing females either did not or could not assess these risks across small scales during oviposition.
Restoration of degraded transitional (piñon–juniper) woodland sites improves ecohydrologic condition and primes understory resilience to subsequent disturbance
Authors: Jacobs Brian F. 
Published: December 2014

AbstractAn overstory thinning and slash mulch treatment designed to improve ecohydrologic condition of degraded transitional (piñon–juniper) woodland sites was evaluated at four sites over a cumulative 16‐year period beginning in 1994. Study sites were located within Bandelier National Monument and Santa Fe National Forest on the east‐facing Pajarito Plateau of the Jemez Mountains in North‐Central New Mexico. Across all sites, total understory cover increased several‐fold at 3 to 5 years post‐treatment relative to both pre‐treatment condition and control, whereas measures of runoff and sediment production were reduced by an order of magnitude. During the course of post‐treatment monitoring, several coincident disturbances (multi‐year drought beginning in fall 1999, wildfire in spring 2000 and piñon ips beetle outbreak in 2002) caused widespread vegetation mortality and allowed differential recovery patterns to be documented across treatment and control areas. Response to these unplanned disturbances suggested prior restoration to improve ecohydrologic function of denuded intercanopy locations also primed understory resilience as measured by the relative capacity of restored areas to regain levels of effective cover. Treatment areas affected by drought‐beetle tree mortality exceeded pre‐drought levels of understory cover within two growing seasons while retaining improved hydrologic function; by contrast, control areas continued to exhibit accelerated runoff and erosion despite temporary improvements in understory cover post‐disturbance. Post‐fire outcomes suggest that prior restoration also enhanced levels of understory cover post‐burn relative to control, despite negative‐soil‐heating effects from consumed slash. Copyright © 2014 John Wiley & Sons, Ltd.
Sap flow and water use sources of shelter‐belt trees in an arid inland river basin of Northwest China
Authors: Shen Qin , Gao Guangyao , Fu Bojie , Lü Yihe 
Published: December 2014

AbstractThe knowledge of plant water use characteristics was essential for ecosystem management and water resources distribution in arid inland river basin. This study was conducted to quantify the sap flow variations and water use sources of shelter‐belt trees at the oasis–desert ecotone in the middle of China's Heihe River Basin. Sap flow was measured by the thermal dissipation method on eight Gansu Poplar (Populus gansuensis) trees with different diameter at breast height in 2012 and 2013. The mean sap flow density increased linearly with diameter at breast height. The sap flow density exhibited linear relationship with solar radiation, and it increased logarithmically with vapour pressure deficit and air temperature, whereas the water table had negative impact on sap flow. The relationship between sap flow and soil relative extractable water at 0–220 cm depth was implicit during the whole growing season, whereas the soil water had apparently positive influence on sap flow after the shelter‐belt trees irrigation. The stand transpiration rate represented as a logarithmic function of reference crop evapotranspiration. The total transpiration of Gansu Poplar during growing season was 599.3 mm, whereas only 58.1% of which was provided by the precipitation and irrigation. The groundwater and cropland irrigation were critical water sources of shelter‐belt trees. The contribution of groundwater to tree transpiration was estimated to be 35.1 and 19.0% in 2012 and 2013, respectively. The great precipitation in 2013 weakened the dependence of tree transpiration on groundwater. The estimated threshold distance of cropland irrigation influencing the tree transpiration was about 8 m. Copyright © 2015 John Wiley & Sons, Ltd.