bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ni‐catalyzed Reductive Cleavage of Methyl 3‐Methoxy‐2‐Naphthoate
Authors: Cornella Josep , Zarate Cayetana , Martin* Ruben 
Published: June 2015

Abstract
The Ni‐catalyzed reductive cleavage was distinguished by its wide scope, including challenging substrate combinations. This article describes a functional group tolerant Ni‐catalyzed reductive cleavage of aryl methyl ethers that occurs with a wide substrate scope. It is believed that such a reaction open up new perspectives in the field of CO bond‐cleavage, a less‐explored but vibrant area of expertise.
Indium‐Catalyzed Heteroaryl–Heteroaryl Bond Formation through Nucleophilic Aromatic Substitution: Preparation of 2‐Methyl‐3‐(thien‐2‐yl)‐1
H
‐indole
Authors: Nagase Yuta , Tsuchimoto* Teruhisa 
Published: June 2015

Abstract

The article describes the synthesis of 2‐methyl‐3‐(thien‐2‐yl)‐1
H
‐indole on a 0.25 mmol scale carried out with 2‐methyl‐1H‐indole and 2‐methoxythiophene in a 1.3:1 molar ratio. The desired product is isolated as a pure form by column chromatography on silica gel. In order to obtain the pure product in such a large‐scale synthesis, the use of a slight excess molar amount of not 2‐methyl‐1H‐indole but 2‐methoxythiophene is important.
3‐Hydroxymethyl‐3‐phenylcyclopropene
Authors: Selvaraj Ramajeyam , Chintala Srinivasa R. , Taylor Michael T. , Fox* Joseph M. 
Published: June 2015

Abstract
The article describes the preparation of 3‐hydroxymethyl‐3‐phenylcyclopropene and modification was reported. This compound and related, prochiral cyclopropenes served as platforms for a number of enantioselective reactions, including enantioselective hydrostannation, hydroacylation, hydroboration, carbomagnesation and carbozincation reactions.
Enantioselective Synthesis of α− and β−Boc‐protected 6‐Hydroxy‐pyranones: Carbohydrate Building Blocks
Authors: Bajaj Sumit O. , Farnsworth Jamison R. , O'Doherty* George A. 
Published: June 2015

Abstract
As part of a larger effort aimed at using the tools of asymmetric synthesis for medicinal chemistry, chemists have been seeking new methods for the de novo asymmetric synthesis of carbohydrates. One broadly applicable asymmetric approach involves the use of α‐ and β‐6‐t‐butoxycarboxy‐2H‐pyran‐3(6H)‐ones as carbohydrate precursors. This article describes the enantioselective synthesis of α‐ and β‐Boc protected 6‐hydroxy‐pyranones.
Consequences of systematic model drift in DYNAMO MJO hindcasts with SP‐CAM and CAM5
Authors: Hannah Walter M. , Maloney Eric D. , Pritchard Michael S. 
Published: June 2015

AbstractHindcast simulations of MJO events during the dynamics of the MJO (DYNAMO) field campaign are conducted with two models, one with conventional parameterization (CAM5) and a comparable model that utilizes superparameterization (SP‐CAM). SP‐CAM is shown to produce a qualitatively better reproduction of the fluctuations of precipitation and low‐level zonal wind associated with the first two DYNAMO MJO events compared to CAM5. Interestingly, skill metrics using the real‐time multivariate MJO index (RMM) suggest the opposite conclusion that CAM5 has more skill than SP‐CAM. This inconsistency can be explained by a systematic increase of RMM amplitude with lead time, which results from a drift of the large‐scale wind field in SP‐CAM that projects strongly onto the RMM index. CAM5 hindcasts exhibit a contraction of the moisture distribution, in which extreme wet and dry conditions become less frequent with lead time. SP‐CAM hindcasts better reproduce the observed moisture distribution, but also have stronger drift patterns of moisture budget terms, such as an increase in drying by meridional advection in SP‐CAM. This advection tendency in SP‐CAM appears to be associated with enhanced off‐equatorial synoptic eddy activity with lead time. Systematic drift moisture tendencies in SP‐CAM are of similar magnitude to intraseasonal moisture tendencies, and therefore are important for understanding MJO prediction skill.
Effects of the passage of Comet C/2013 A1 (Siding Spring) observed by the Shallow Radar (SHARAD) on Mars Reconnaissance Orbiter
Authors: Restano Marco , Plaut Jeffrey J. , Campbell Bruce A. , Gim Yonggyu , Nunes Daniel , Bernardini Fabrizio , Egan Anthony , Seu Roberto , Phillips Roger J. 
Published: June 2015

AbstractThe close passage of Comet C/2013 A1 (Siding Spring) to Mars provided a unique opportunity to observe the interaction of cometary materials with the Martian ionosphere and atmosphere using the sounding radar SHARAD (SHAllow RADar) aboard Mars Reconnaissance Orbiter. In two nightside observations, acquired in the 10 h following the closest approach, the SHARAD data reveal a significant increase of the total electron content (TEC). The observed TEC values are typical for daylight hours just after dawn or before sunset but are unprecedented this deep into the night. Results support two predictions indicating that cometary pickup O+ ions, or ions generated from the ablation of cometary dust, are responsible for the creation of an additional ion layer.
Great earthquakes in low strain rate continental interiors: An example from SE Kazakhstan
Authors: Campbell G. E. , Walker R. T. , Abdrakhmatov K. , Jackson J. , Elliott J. R. , Mackenzie D. , Middleton T. , Schwenninger J.‐L. 
Published: June 2015

AbstractThe Lepsy fault of the northern Tien Shan, SE Kazakhstan, extends E‐W 120 km from the high mountains of the Dzhungarian Ala‐tau, a subrange of the northern Tien Shan, into the low‐lying Kazakh platform. It is an example of an active structure that connects a more rapidly deforming mountain region with an apparently stable continental region and follows a known Palaeozoic structure. Field‐based and satellite observations reveal an ∼10 m vertical offset exceptionally preserved along the entire length of the fault. Geomorphic analysis and age control from radiocarbon and optically stimulated luminescence dating methods indicate that the scarp formed in the Holocene and was generated by at least two substantial earthquakes. The most recent event, dated to sometime after ∼400 years B.P., is likely to have ruptured the entire ∼120 km fault length in aMw7.5–8.2 earthquake. The Lepsy fault kinematics were characterized using digital elevation models and high‐resolution satellite imagery, which indicate that the predominant sense of motion is reverse right lateral with a fault strike, dip, and slip vector azimuth of ∼110°, 50°S, and 317–343°, respectively, which is consistent with predominant N‐S shortening related to the India‐Eurasia collision. In light of these observations, and because the activity of the Lepsy fault would have been hard to ascertain if it had not ruptured in the recent past, we note that the absence of known active faults within low‐relief and low strain rate continental interiors does not always imply an absence of seismic hazard.
Large eddy simulation using the general circulation modelICON
Authors: Dipankar Anurag , Stevens Bjorn , Heinze Rieke , Moseley Christopher , Zängl Günther , Giorgetta Marco , Brdar Slavko 
Published: June 2015

AbstractICON (ICOsahedral Nonhydrostatic) is a unified modeling system for global numerical weather prediction (NWP) and climate studies. Validation of its dynamical core against a test suite for numerical weather forecasting has been recently published by Zängl et al. (2014). In the present work, an extension of ICON is presented that enables it to perform as a large eddy simulation (LES) model. The details of the implementation of the LES turbulence scheme in ICON are explained and test cases are performed to validate it against two standard LES models. Despite the limitations that ICON inherits from being a unified modeling system, it performs well in capturing the mean flow characteristics and the turbulent statistics of two simulated flow configurations—one being a dry convective boundary layer and the other a cumulus‐topped planetary boundary layer.
Balanced dynamics and convection in the tropical troposphere
Authors: Raymond David , Fuchs Željka , Gjorgjievska Saška , Sessions Sharon 
Published: June 2015

AbstractThis paper presents a conceptual picture of balanced tropical tropospheric dynamics inspired by recent observations. The most important factor differentiating the tropics from middle and higher latitudes is the absence of baroclinic instability; upward motion occurs primarily via deep convective processes. Thus, convection forms an integral part of large‐scale tropical motions. Since convection itself is small‐scale and chaotic in detail, predictability lies in uncovering the hidden hands that guide the average behavior of convection. Two appear, balanced dynamics and thermodynamic constraints. Contrary to conventional expectations, balanced dynamics plays a crucial role in the tropical atmosphere. However, due to the smallness of the Coriolis parameter there, nonlinear balance is more important in the tropics than at higher latitudes. Three thermodynamic constraints appear to play an important role in governing the average behavior of convection outside of the cores of tropical storms. First, convection is subject to control via a lower tropospheric buoyancy quasi‐equilibrium process, wherein destabilization of the lower troposphere by nonconvective processes is balanced by convective stabilization. Second, the production of precipitation is extraordinarily sensitive to the saturation fraction of the troposphere. Third, “moisture quasi‐equilibrium” governs the saturation fraction, with moister atmospheres being associated with smaller moist convective instability. The moist convective instability is governed by the balanced thermodynamic response to the pattern of potential vorticity, which in turn is slowly modified by convective and radiative heating. The intricate dance between these dynamic and thermodynamic processes leads to complex behavior of the tropical atmosphere in ways that we are just beginning to understand.
Bridging the gap between models and measurements of peat hydraulic conductivity
Authors: Morris Paul J. , Baird Andy J. , Belyea Lisa R. 
Published: June 2015

AbstractPeat saturated hydraulic conductivity, Ksat, declines strongly with increasing degree of decomposition, providing a potentially important negative ecohydrological feedback that may buffer peatlands from climate‐induced drying. However, the quantitative nature of this relationship is poorly understood. We measured downcore changes in Ksat and carbon‐to‐nitrogen concentration quotients (C/N) in 14 shallow (∼0.5 m deep, 0.1 m diameter) peat cores from a Swedish raised bog. We used the C/N measurements to approximate the fraction of original peat mass remaining. A linear mixed effects (LME) model predicts log10(Ksat) from (i) our C/N‐derived estimate of fractional remaining mass; (ii) depth; (iii) microhabitat (hummock, hollow); and (iv) location (treeless bog center, treed bog margin). The LME model indicated no significant random effects or interactions between predictors, so we derived a nonlinear multiple regression (NLMR) model to predict Ksat on its original scale. Both LME and NLMR models predict that Ksat decreases exponentially with depth and that Ksat is lower beneath hollows than beneath hummocks for equivalent depths below the surface. Fractional remaining mass was an important predictor in the LME model, but not in the NLMR model. The distinction between central and marginal areas of the bog was not an important predictor. We demonstrate for the first time that the relationship between fractional remaining mass and Ksat is log‐linear, and suggest revisions that should be made to peatland development models. In particular, depth—usually ignored in modeling studies—exerted a strong control over Ksat independently of decomposition and should be included explicitly in model algorithms.
Hydraulic fracturing water use variability in theUnitedStates and potential environmental implications
Authors: Gallegos Tanya J. , Varela Brian A. , Haines Seth S. , Engle Mark A. 
Published: June 2015

AbstractUntil now, up‐to‐date, comprehensive, spatial, national‐scale data on hydraulic fracturing water volumes have been lacking. Water volumes used (injected) to hydraulically fracture over 263,859 oil and gas wells drilled between 2000 and 2014 were compiled and used to create the first U.S. map of hydraulic fracturing water use. Although median annual volumes of 15,275 m3and 19,425 m3of water per well was used to hydraulically fracture individual horizontal oil and gas wells, respectively, in 2014, about 42% of wells were actually either vertical or directional, which required less than 2600 m3water per well. The highest average hydraulic fracturing water usage (10,000−36,620 m3per well) in watersheds across the United States generally correlated with shale‐gas areas (versus coalbed methane, tight oil, or tight gas) where the greatest proportion of hydraulically fractured wells were horizontally drilled, reflecting that the natural reservoir properties influence water use. This analysis also demonstrates that many oil and gas resources within a given basin are developed using a mix of horizontal, vertical, and some directional wells, explaining why large volume hydraulic fracturing water usage is not widespread. This spatial variability in hydraulic fracturing water use relates to the potential for environmental impacts such as water availability, water quality, wastewater disposal, and possible wastewater injection‐induced earthquakes.
Uncertainty in global groundwater storage estimates in a Total Groundwater Stress framework
Authors: Richey Alexandra S. , Thomas Brian F. , Lo Min‐Hui , Famiglietti James S. , Swenson Sean , Rodell Matthew 
Published: June 2015

AbstractGroundwater is a finite resource under continuous external pressures. Current unsustainable groundwater use threatens the resilience of aquifer systems and their ability to provide a long‐term water source. Groundwater storage is considered to be a factor of groundwater resilience, although the extent to which resilience can be maintained has yet to be explored in depth. In this study, we assess the limit of groundwater resilience in the world's largest groundwater systems with remote sensing observations. The Total Groundwater Stress (TGS) ratio, defined as the ratio of total storage to the groundwater depletion rate, is used to explore the timescales to depletion in the world's largest aquifer systems and associated groundwater buffer capacity. We find that the current state of knowledge of large‐scale groundwater storage has uncertainty ranges across orders of magnitude that severely limit the characterization of resilience in the study aquifers. Additionally, we show that groundwater availability, traditionally defined as recharge and redefined in this study as total storage, can alter the systems that are considered to be stressed versus unstressed. We find that remote sensing observations from NASA's Gravity Recovery and Climate Experiment can assist in providing such information at the scale of a whole aquifer. For example, we demonstrate that a groundwater depletion rate in the Northwest Sahara Aquifer System of 2.69 ± 0.8 km3/yr would result in the aquifer being depleted to 90% of its total storage in as few as 50 years given an initial storage estimate of 70 km3.
Occupational and environmental risk factors for chronic rhinosinusitis: a systematic review
Authors: Sundaresan Agnes S. , Hirsch Annemarie G. , Storm Margaret , Tan Bruce K. , Kennedy Thomas L. , Greene J. Scott , Kern Robert C. , Schwartz Brian S. 
Published: June 2015

BackgroundChronic rhinosinusitis (CRS) is a prevalent and disabling paranasal sinus disease, with a likely multifactorial etiology potentially including hazardous occupational and environmental exposures. We completed a systematic review of the occupational and environmental literature to evaluate the quality of evidence of the role that hazardous exposures might play in CRS.MethodsWe searched PubMed for studies of CRS and following exposure categories: occupation, employment, work, industry, air pollution, agriculture, farming, environment, chemicals, roadways, disaster, and traffic. We abstracted information from the final set of articles across 6 primary domains: study design; population; exposures evaluated; exposure assessment; CRS definition; and results.ResultsWe identified 41 articles from 1080 manuscripts: 37 occupational risk papers, 1 environmental risk paper, and 3 papers studying both categories of exposures. None of the 41 studies used a CRS definition consistent with current diagnostic guidelines. Exposure assessment was generally dependent on self‐report or binary measurements of exposure based on industry of employment. Only grain, dairy, and swine operations among farmers were evaluated by more than 1 study using a common approach to defining CRS, but employment in these settings was not consistently associated with CRS. The multiple other exposures did not meet quality standards for reporting associations or were not evaluated by more than 1 study.ConclusionThe current state of the literature allows us to make very few conclusions about the role of hazardous occupational or environmental exposures in CRS, leaving a critical knowledge gap regarding potentially modifiable risk factors for disease onset and progression.
Olfactory change after intensity‐modulated radiotherapy for nasopharyngeal carcinoma
Authors: Wang Jing‐Jie , Liang Kai‐Li , Twu Chih‐Wen , Lin Jin‐Ching , Jiang Rong‐San 
Published: June 2015

BackgroundRadiotherapy is the mainstay of treatment for nasopharyngeal cancer (NPC), but many side effects were reported in NPC patients receiving radiotherapy. This study was conducted to evaluate the long‐term effects of intensity‐modulated radiotherapy (IMRT) on olfactory function.MethodsThe olfactory function of 41 NPC patients was assessed by a traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT‐TC). The patients also filled out a Taiwanese version of the 22‐item Sino‐Nasal Outcome Test (TWSNOT‐22) questionnaire and received imaging examinations of the sinuses before IMRT and 1 year after IMRT. The sinus imaging was scored according to the Lund‐Mackay system.ResultsThe mean UPSIT‐TC scores were 30.6 before IMRT and 28.0 after IMRT and the decrease in UPSIT‐TC scores was significant (p = 0.001). The mean TWSNOT‐22 scores were 32.1 before IMRT and 28.8 after IMRT. The change in TWSNOT‐22 scores was not significant, but the scores for item 5 “loss of smell or taste” significantly increased after IMRT (p = 0.035). The mean total computed tomography (CT) scores were 1.7 before IMRT and 3.2 after IMRT, and the mean ethmoid CT scores were 0.5 before IMRT and 1.2 after IMRT. The increase in total CT and ethmoid CT scores was both significant (p = 0.004 and 0.002). The decrease in UPSIT‐TC scores was moderately negatively correlated with the increase in total CT and ethmoid CT scores (r = −0.348 and −0.423).ConclusionOur results showed that the olfactory function of NPC patients was mildly impaired after IMRT, which can cause rhinosinusitis.
Photokatalysatoren auf Graphenbasis für die Produktion von Solarbrennstoffen
Authors: Xiang Quanjun , Cheng Bei , Yu Jiaguo 
Published: June 2015

AbstractAufgrund des zunehmenden Energiebedarfs und wachsender Umweltprobleme erfahren die Produktion von Solarbrennstoffen durch photokatalytische Wasserspaltung und die CO2‐Reduktion mithilfe von Photokatalysatoren beträchtliches Interesse. In den letzten Jahren haben zahlreiche Studien gezeigt, dass die Effizienz der Photokatalysatoren für die Produktion von Solarbrennstoffen deutlich gesteigert werden kann, wenn man Graphen verwendet, das eine besondere konjugierte 2D‐Struktur und spezielle elektronischen Eigenschaften besitzt. Dieser Aufsatz gibt einen Überblick über jüngste Fortschritte bei der Anwendung von Photokatalysatoren auf Graphenbasis für die Produktion von Solarbrennstoffen einschließlich der CO2‐Reduktion zu Kohlenwasserstoffen und der H2‐Erzeugung mittels Wasserspaltung. Die Grundlagen der Wasserspaltung und der CO2‐Reduktion werden kurz dargestellt. Die für die Verbesserung der photokatalytischen Leistung relevanten Funktionen des Graphens werden diskutiert. Mit Blick auf bestehende Herausforderungen und Möglichkeiten auf diesem vielversprechenden Gebiet werden schließlich mögliche Perspektiven erörtert.
Eine kurze und divergente Totalsynthese von (+)‐Machaeriol B, (+)‐Machaeriol D, (+)‐Δ8‐THC und zugehörigen Analoga
Authors: Klotter Felix , Studer Armido 
Published: June 2015

AbstractEin kurzer und divergenter Syntheseweg mit hoch effizienten stereoselektiven Umsetzungen liefert Machaeriole und Cannabinoide aus einer gemeinsamen Vorstufe, der kommerziell erhältlichen (S)‐Perillasäure. Schlüsselschritte des neuen Ansatzes sind eine stereospezifische Pd‐katalysierte decarboxylierende Arylierung und eine Eintopf‐Sequenz aus stereoselektiver Hydroborierung mit anschließender Oxidation bzw. Reduktion der Boran‐Intermediate. Die divergente Strategie ließ sich überzeugend für je fünfstufige Synthesen von (+)‐Machaeriol B, (+)‐Machaeriol D sowie zugehörigen Analoga und für eine vierstufige Sequenz zu (+)‐Δ8‐THC und einem seiner Derivate heranziehen.
Convergent Versus Sequential Protein Synthesis: The Case of Ubiquitinated and Glycosylated H2B
Authors: Seenaiah Mallikanti , Jbara Muhammad , Mali Sachitanand M. , Brik Ashraf 
Published: June 2015

AbstractThe chemical synthesis of a protein from four fragments or more applying native chemical ligation could be achieved stepwise, in one‐pot, convergently, or on a solid support. With the increasing demands of applying protein synthesis to highly complex targets, examining these approaches becomes essential to achieve highly efficient synthesis. Different chemical synthetic strategies are compared for the preparation of the H2B protein having different post‐translational modifications. The analogues include H2B that is ubiquitinated at Lys34, Lys120, glycosylated at Ser112, and doubly modified with ubiquitin and N‐acetylglucosamine. This study demonstrates that the applied convergent strategy for the synthesis of most of these complex targets was better than the one‐pot approach in terms of yield and purity. Some guidelines are offered for future synthetic endeavors of similar challenging proteins.
A Perylene Bisimide Cyclophane as a “Turn‐On” and “Turn‐Off” Fluorescence Probe
Authors: Spenst Peter , Würthner Frank 
Published: June 2015

AbstractA rigid, covalently linked perylene‐3,4:9,10‐tetracarboxylic acid bisimide (PBI) cyclophane was synthesized by imidization of a bay‐substituted perylene bisanhydride with p‐xylylenediamine. The interchromophoric distance of approximately 6.5 Å establishes an ideal rigid cavity for the encapsulation of large aromatic compounds such as perylene and anthracene with binding constants up to 4.6×104 M−1 (in CHCl3). For electron‐poor guest molecules, the complexation process is accompanied by a significantly increased fluorescence, whereas the emission intensity is dramatically quenched by more electron‐rich guests because of the formation of charge‐transfer complexes. Furthermore, the influence of the PBI core twist on the binding constant results in a remarkable selectivity towards more flexible aromatic guest molecules.