bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerobic Epoxidation of Olefins Catalyzed by the Cobalt‐Based Metal–Organic Framework STA‐12(Co)
Authors: Beier Matthias J. , Kleist Wolfgang , Wharmby Michael T. , Kissner Reinhard , Kimmerle Bertram , Wright Paul A. , Grunwaldt Jan‐Dierk , Baiker Alfons 
Published: December 2011

AbstractA Co‐based metal–organic framework (MOF) was investigated as a catalytic material in the aerobic epoxidation of olefins in DMF and exhibited, based on catalyst mass, a remarkably high catalytic activity compared with the Co‐doped zeolite catalysts that are typically used in this reaction. The structure of STA‐12(Co) is similar to that of STA‐12(Ni), as shown by XRD Rietveld refinement and is stable up to 270 °C. For the epoxidation reaction, significantly different selectivities were obtained depending on the substrate. Although styrene was epoxidized with low selectivity due to oligomerization, (E)‐stilbene was converted with high selectivities between 80 and 90 %. Leaching of Co was low and the reaction was found to proceed mainly heterogeneously. The catalyst was reusable with only a small loss of activity. The catalytic epoxidation of stilbene with the MOF featured an induction period, which was, interestingly, considerably reduced by styrene/stilbene co‐epoxidation. This could be traced back to the formation of benzaldehyde promoting the reaction. Detailed parameter and catalytic studies, including in situ EPR and EXAFS spectroscopy, were performed to obtain an initial insight into the reaction mechanism.
Rational Design of Ambipolar Organic Semiconductors: Is Core Planarity Central to Ambipolarity in Thiophene–Naphthalene Semiconductors?
Authors: Ortiz Rocío Ponce , Herrera Helena , Seoane Carlos , Segura José L. , Facchetti Antonio , Marks Tobin J. 
Published: December 2011

AbstractHerein, we report a new family of naphthaleneamidinemonoimide‐fused oligothiophene semiconductors designed for facile charge transport in organic field‐effect transistors (OFETs). These molecules have planar skeletons that induce high degrees of crystallinity and hence good charge‐transport properties. By modulating the length of the oligothiophene fragment, the majority carrier charge transport can be switched from n‐type to ambipolar behavior. The highest FET performance is achieved for solution‐processed films of 10‐[(2,2′‐bithiophen)‐5‐yl]‐2‐octylbenzo[lmn]thieno[3′,4′:4,5]imidazo[2,1‐b][3,8]phenanthroline‐1,3,6(2 H)‐trione (NDI‐3 Tp), with optimized film mobilities of 2×10−2 and 0.7×10−2 cm2 V−1 s−1 for electrons and holes, respectively. Finally, these planar semiconductors are compared with their twisted‐skeleton counterparts, which exhibit only n‐type mobility, in order to understand the origin of the ambipolarity in this new series of molecular semiconductors.
Grading Woodland Soil Water Productivity and Soil Bioavailability in the Semi‐Arid Loess Plateau of China
Authors: Zhang Guang‐Can , Xia Jiang‐Bao , Shao Hong‐Bo , Zhang Shu‐Yong 
Published: December 2011

AbstractIn the semi‐arid region of the Loess Plateau in China, a portable photosynthesis system (Li‐6400) and a portable steady porometer (Li‐1600) were used to study the quantitative relation between the soil water content (SWC) and trees' physiological parameters including net photosynthesis rate (Pn), carboxylation efficiency (CE), transpiration rate (Tr), water use efficiency of leaf (WUEL), stomatic conductivity (Gs), stomatal resistance (Rs), intercellular CO2 (Ci), and stomatal limitation (Ls). These are criteria for grading and evaluating soil water productivity and availability in forests of Black Locust (Robinia pseudoacacia) and Oriental Arborvitae (Platycladus orientalis). The results indicated: To the photosynthesis of Locust and Arborvitae, the SWC of less than 4.5 and 4.0% (relative water content (RWC) 21.5 and 19.0%) belong to “non‐productivity and non‐efficiency water”; the SWC of 4.5–10.0% (RWC 21.5–47.5%) and 4.0–8.5% (RWC 19.0–40.5%) belong to “low productivity and low efficiency water”; the SWC of 10.0–13.5% (RWC 47.5–64.0%) and 8.5–11.0% (RWC 40.5–52.0%) belong to “middle productivity and high efficiency water”; the SWC of 13.5–17.0% (RWC 64.0–81.0%) and 11.0–16.0% (RWC 52.0–76.0%) belong to “high productivity and middle efficiency water”; the SWC of 17.0–19.0% (RWC 81.0–90.5%) and 16.0–19.0% (RWC 76.0–90.5%) belong to “middle productivity and low efficiency water”; the SWC of more than 19.0% (RWC 90.5%) belongs to “low productivity and low efficiency water”. The SWC of about 13.5 and 11.0% (RWC 64.0 and 52.0%) are called “high productivity and high efficiency water”, which provides the further evidence for Locust and Arborvitae to get both higher productivity (Pn and CE) and the highest WUEL and adaptation to the local environment, respectively.
Soil Seed Banks and Forest Succession Direction Reflect Soil Quality in Ziwuling Mountain, Loess Plateau, China
Authors: Cheng Jimin , Cheng Jie , Shao Hongbo , Zhao Lingping , Yang Xiaomei 
Published: December 2011

AbstractThe paper presents a study by taking the soil seed banks and vegetation successions of the forests in Ziwuling Mountain as indicators to analyze the effects of the ages, and the litter layers and soil depths at growing locations in seven types of forest communities on their seed bank formations and soil quality. The results showed that the seed banks at different growing locations in the communities increased in the order of upper slope, middle slope, and lower slope; the seed storages of the seed banks in the different layers of the communities varied, much more higher in the litter layers than in 0–15 cm, and the seed storages of the seed banks in the seven types of forest communities ranked in the increasing order of Pinus tabulaeformis forest, Pinus shenkaneusis forest, Quercus liaotungensis forest, Populus davidiana forest, Betula platyphylla forest, scrub communities, and grassland communities; in the meantime, the seed storage of seed banks peaked in 30–50 years old P. shenkaneusis forest, 30–40 years old P. tabulaeformis forest, 15–30 years old Q. liaotungensis, and P. davidiana and B. platyphylla forests, and 10–15 years old scrub and grassland communities, and the ages of the communities varied with the seed storages of the seed banks in a significantly correlative manner following a fitted exponential equation. In addition, the soil seed banks of the seven types of communities consisted of rich and diverse species with the herbaceous and shrub species greatly outnumbering the arbor species; in general, the coniferous forests were composed of 31 kinds of plants, the deciduous and broadleaf forests consisted of 20–29 plant species, the shrubs contained 27 plant species, and the herbaceous plants numbered 20 plant species; The various species compositions contained only 4–6 arbor species with most being foreign species. In each of the compositions, Bothriochloa ischemum was the grassland plant with the highest occurrence frequency, Sophora viciifolia and Hippophae reamnoides were the shrub plants with the highest occurrence frequencies, and Q. liaotungensis was the arbor plant with the highest occurrence frequency, and they followed by P. shenkaneusis and P. tabulaeformis. These results showed that soil seed banks and forest successions are better indicators for soil quality from natural successions.
Morphology Controlled Nanostructures Self‐Assembled from Phthalocyanine Derivatives Bearing Alkylthio Moieties: Effect of Sulfur–Sulfur and Metal–Ligand Coordination on Intermolecular Stacking
Authors: Hao Zijuan , Wu Xingcui , Sun Ranran , Ma Changqin , Zhang Xiaomei 
Published: December 2011

AbstractTo investigate the effect of sulfur–sulfur and metal–ligand coordination on the molecular structure and morphology of self‐assembled nanostructures, metal‐free 2,3,9,10,16,17,23,24‐octakis(isopropylthio)phthalocyanine H2Pc(β‐SC3H7)8 (1) and its copper and lead congeners CuPc(β‐SC3H7)8 (2) and PbPc(β‐SC3H7)8 (3) are synthesized and fabricated into organic nanostructures by a phase‐transfer method. The self‐assembly properties are investigated by electronic absorption and Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). Experimental results reveal different molecular packing modes in these aggregates, which in turn result in self‐assembled nanostructures with different morphologies ranging from nanobelts for 1 through nanoribbons for 2 to cluster nanoflowers for 3. Intermolecular π–π and sulfur–sulfur interactions between metal‐free phthalocyanine 1 lead to the formation of nanobelts. The additional CuS coordination bond between the central copper ion of 2 and the sulfur atom of the adjacent molecule of 2 in cooperation with the intermolecular π–π stacking interaction increases the intermolecular interaction, and results in the formation of long nanoribbons for 2. In contrast to compounds 1 and 2, the special molecular structure of complex 3, together with the intermolecular π–π stacking interaction and additional PbS coordination bond, induces the formation of Pb‐connected pseudo‐double‐deckers during the self‐assembly process, which in turn further self‐assemble into cluster nanoflowers. In addition, good semiconducting properties of the nanostructures fabricated from phthalocyanine derivatives 1–3 were also revealed by I–V measurements.
Do patients with type 2 diabetes mellitus have an increased prevalence of Cushing's syndrome?
Authors: Krarup Therese , Krarup Thure , Hagen Claus 
Published: December 2011

SummaryMany clinical features are common for patients with type 2 diabetes mellitus (T2DM) and Cushing's syndrome (CS) such as central obesity, hypertension and dyslipidaemia. Patients with CS often have T2DM. Because T2DM is much more frequent than CS, it is possible that some patients with T2DM have increased production of cortisol and thus represent patients with CS. The aim of this review was to evaluate the prevalence of CS in patients with T2DM. A search was performed in PubMed and Medline. We found seven prospective studies, two case–control studies and two cross‐sectional studies. The difficulties in diagnosing subclinical CS is discussed. The most frequent tests for diagnosing CS, late‐night salivary cortisol, 1‐mg dexamethasone suppression test and urinary free cortisol are discussed and put in relation to the results of the literature found. The observed prevalence of CS in patients with T2DM varies widely between the different studies, ranging from 0–9.4%. This may be due to patient selection, differences in test methodology (including choice of test), cutoff values and different cortisol assays. The true prevalence of CS in T2DM has not been determined. We need more studies investigating the prevalence of CS in T2DM patients. There is a need for developing more specific tests for diagnosing CS in patients with only slightly elevated cortisol secretion and subclinical CS. We suggest that examination for hypercortisolism should only be performed in T2DM patients with a cushingoid appearance and hypertension or truncal obesity or dyslipidaemia. Copyright © 2011 John Wiley & Sons, Ltd.
Biogeomorphology of tidal landforms: physical and biological processes shaping the tidal landscape
Authors: D'Alpaos Andrea , Da Lio Cristina , Marani Marco 
Published: December 2011

ABSTRACTWe analyse the equilibrium states and transient dynamics of tidal biogeomorphic systems, such as lagoons and estuaries, in response to variations in the governing physical and biological forcings, such as tidal range, wind climate, sediment supply, vegetation, and microphytobenthos growth, and rates of relative sea level rise (RSLR). We use a point model of the coupled elevation–vegetation dynamics, which retains the description of the chief processes shaping these systems. We observe that salt marshes exposed to large tidal ranges are more stable, and therefore more resilient to increasing rates of RSLR, than marshes subjected to low tidal ranges. Furthermore, subtidal platforms in macrotidal systems are less exposed to wind‐induced erosion processes than their counterparts in systems with smaller tidal fluctuations. Notably, we find that vegetation crucially affects both the equilibrium marsh elevation, through dissipation of wind waves and organic accumulation, and marsh resilience to accelerations in RSLR rates. Moreover, the biomass production as a function of elevation associated with the presence of different vegetation species, as opposed to mono‐specific vegetation covers, increases marsh stability and resilience in the face of increasing rates of RSLR. Finally, our results show that the existence and stability of equilibrium states fundamentally depend on the local wind and tidal regime, even within the same tidal system, with important biogeomorphic implications. In summary, our model analyses of physical and biological controls of tidal system dynamics highlight the importance of accounting for biogeomorphic feedback to obtain realistic representations of the system dynamics in response to climatic changes. Copyright © 2011 John Wiley & Sons, Ltd.
Perforin plays an unexpected role in regulating T‐cell contraction during prolonged Listeria monocytogenes infection
Authors: Schmidt Nathan W. , Khanolkar Aaruni , Hancox Lisa , Heusel Jonathan W. , Harty John T. 
Published: December 2011

AbstractAfter infection or vaccination, antigen‐specific T cells proliferate then contract in numbers to a memory set point. T‐cell contraction is observed after both acute and prolonged infections although it is unknown if contraction is regulated similarly in both scenarios. Here, we show that contraction of antigen‐specific CD8+ and CD4+ T cells is markedly reduced in TNF/perforin‐double deficient (DKO) mice responding to attenuated Listeria monocytogenes infection. Reduced contraction in DKO mice was associated with delayed clearance of infection and sustained T‐cell proliferation during the normal contraction interval. Mechanistically, sustained T‐cell proliferation mapped to prolonged infection in the absence of TNF; however, reduced contraction required the additional absence of perforin since T cells in mice lacking either TNF or perforin (singly deficient) underwent normal contraction. Thus, while T‐cell contraction after acute infection is independent of peforin, a perforin‐dependent pathway plays a previously unappreciated role to mediate contraction of antigen‐specific CD8+ and CD4+ T cells during prolonged L. monocytogenes infection.
New Approach to [FeFe]‐Hydrogenase Models Using Aromatic Thioketones
Authors: Daraosheh Ahmad Q. , Apfel Ulf‐Peter , Görls Helmar , Friebe Christian , Schubert Ulrich S. , El‐khateeb Mohammad , Mloston Grzegorz , Weigand Wolfgang 
Published: December 2011

AbstractThe reactions of triiron dodecacarbonyl with thiobenzophenone (2a) and 9H‐thioxanthene‐9‐thione (2b) were investigated under different conditions. In the case of a 1:1 molar ratio of triiron dodecacarbonyl and 2a or 2b, the ortho‐metallated complexes [Fe2(CO)6{μ,κ,S,SCH(C6H5)C6H4‐η2}] (3a) and [Fe2(CO)6{μ,κ,S,SCH(C6H4)–S–C6H3‐η2}] (4a) were obtained as the major products, respectively. In contrast, the treatment of triiron dodecacarbonyl with an excess of 2a or 2b afforded [Fe2(CO)6{μ‐SCH(C6H5)C6H4S‐μ}] (3b) and [Fe2(CO)6{μ‐SCH(C6H4)–S–C6H3S‐μ}] (4b), respectively, which are both bioinspired models for the active site of [FeFe]‐hydrogenase. In addition to these complexes, the two reactions afforded [Fe2(CO)6{μ‐SC(C6H5)2S‐μ}] (3c) and [Fe2(CO)6{μ‐SC(C6H4–S–C6H4)S‐μ}] (4c). Furthermore, [{Fe2(CO)6{μ‐SCH(C6H5)2}}2(μ4‐S)] (3d) was isolated from the reaction of Fe3(CO)12 with 2a. The molecular structures of all of the new complexes were determined from the spectroscopic and analytical data and the crystal structures for 3c, 3d, 4b, and 4c were obtained. A plausible mechanism for the formation of the isolated complexes that involves dithiirane derivatives as the key intermediates is proposed. Herein, thioketones 2a and 2b act as sulfur transfer reagents. The electrochemical experiments showed that complex 3b behaves as a catalyst for the electrochemical reduction of protons from acetic acid.
Lipophilic components in black currant seed and pomace extracts
Authors: Dobson Gary , Shrestha Marie , Hilz Hauke , Karjalainen Reijo , McDougall Gordon , Stewart Derek 
Published: December 2011

AbstractThe nature of the fatty acids and other lipophilic components in extracts from black currant seed and pomace (containing seed) were investigated, with a view to highlighting any potential uses. The same non‐hydroxylated fatty acids were the major components in both types of extract, but total levels were less in pomace (75 582 mg 100 g−1 oil) than in seed alone (90 972 mg 100 g−1 oil) and there were less unsaturated fatty acids, including GLA (8653 and 12 625 mg 100 g−1 oil, respectively), but long chain n‐20:0 – n‐30:0 fatty acids (4080 and 437 mg 100 g−1 oil, respectively) were greatly increased in pomace. Phytosterols (mainly β‐sitosterol), saturated n‐20:0 – n‐30:0 policosanols, ω‐hydroxy fatty acids (mainly 16‐hydroxy 16:0) and 2‐hydroxy fatty acids (mainly 2‐hydroxy 24:0) were present at much greater levels in pomace (2496, 2097, 958 and 46 mg 100 g−1 oil, respectively) than in seed (553, 108, 161, and 1 mg 100 g−1 oil, respectively). The pomace extract is a useful source of fatty acids, phytosterols and policosanols with potential functional properties.Practical applications: The study investigated the lipophilic components in isohexane extracts from black currant seed and pomace (containing seed). Only pomace extracts had substantial amounts of phytosterols and policosanols that have potential as cholesterol‐lowering agents, whereas fatty acids such as GLA, that has anti‐inflammatory properties, are mainly in the seed.
Copper‐Mediated C–H Activation of 1,3,4‐Oxadiazoles with 1,1‐Dibromo‐1‐alkenes Using PEG‐400 as a Solvent Medium: Distinct Approach for the Alkynylation of 1,3,4‐Oxadiazoles
Authors: Reddy Gandolla Chinna , Balasubramanyam Penagaluri , Salvanna N. , Das Biswanath 
Published: December 2011

AbstractThe direct C–H alkynylation of 1,3,4‐oxadiazoles with 1,1‐dibromo‐1‐alkenes has been accomplished by using a combination of CuBr/LiOtBu in PEG‐400 (a green solvent) at 80 °C. The products were formed in high yields (73–86 %) in 2 h. No additional ligand or volatile solvent was required and the conversion was ecofriendly.
Progressive failure of sheeted rock slopes: the 2009–2010 Rhombus Wall rock falls in Yosemite Valley, California, USA
Authors: Stock Greg M. , Martel Stephen J. , Collins Brian D. , Harp Edwin L. 
Published: December 2011

ABSTRACTProgressive rock‐fall failures in natural rock slopes are common in many environments, but often elude detailed quantitative documentation and analysis. Here we present high‐resolution photography, video, and laser scanning data that document spatial and temporal patterns of a 15‐month‐long sequence of at least 14 rock falls from the Rhombus Wall, a sheeted granitic cliff in Yosemite Valley, California. The rock‐fall sequence began on 26 August 2009 with a small failure at the tip of an overhanging rock slab. Several hours later, a series of five rock falls totaling 736 m3 progressed upward along a sheeting joint behind the overhanging slab. Over the next 3 weeks, audible cracking occurred on the Rhombus Wall, suggesting crack propagation, while visual monitoring revealed opening of a sheeting joint adjacent to the previous failure surface. On 14 September 2009 a 110 m3 slab detached along this sheeting joint. Additional rock falls between 30 August and 20 November 2010, totaling 187 m3, radiated outward from the initial failure area along cliff (sub)parallel sheeting joints. We suggest that these progressive failures might have been related to stress redistributions accompanying propagation of sheeting joints behind the cliff face. Mechanical analyses indicate that tensile stresses should occur perpendicular to the cliff face and open sheeting joints, and that sheeting joints should propagate parallel to a cliff face from areas of stress concentrations. The analyses also account for how sheeting joints can propagate to lengths many times greater than their depths behind cliff faces. We posit that as a region of failure spreads across a cliff face, stress concentrations along its margin will spread with it, promoting further crack propagation and rock falls. Published in 2012. This article is a US Government work and is in the public domain in the USA.
Health care and patient safety: The failure of traditional approaches – how human factors and ergonomics can and MUST help
Authors: Bagian James P. 
Published: December 2011

AbstractHazard and harm to patients as well as inefficiencies associated with health care have been well described as worldwide problems that result in hundreds of thousands of patient deaths and billions of dollars of waste every year. The underlying causes for these problems have not been nearly so well described; more importantly, generalizable mitigation strategies have not been effectively identified or used. The current state of health care and patient safety will be discussed with particular attention to the essential role that an engineering‐based approach, which is heavily rooted in human factors and ergonomics, must play if real and sustainable progress in the safe and efficient delivery of health care is to be achieved. Specific case studies that illustrate the compelling opportunities for the application of human factors and ergonomics–related knowledge will be discussed. © 2011 Wiley Periodicals, Inc.
A new model of job design: Initial evidence and implications for future research
Authors: Challenger Rose , Leach Desmond J. , Stride Christopher B. , Clegg Chris W. 
Published: December 2011

AbstractClegg and Spencer's (2007) model of job design synthesizes and extends recent conceptions of the job design process by incorporating variables such as knowledge, motivation, and trust into a cyclical and dynamic system. The objective of this study was to examine the sequential organization of variables that comprise the model, as a basis from which to justify further investigations of the model's dynamic properties. Data were collected via questionnaires from 432 participants in two work organizations. Results obtained from structural equation modeling are broadly supportive of the proposed relationships between the variables. Implications of this initial study for future research and practice are discussed. © 2011 Wiley Periodicals, Inc.
The role of organizational factors in achieving reliability in the design and manufacture of subsea equipment
Authors: Parkes Katharine , Hodkiewicz Melinda , Morrison David 
Published: December 2011

AbstractFailures of equipment used in deepwater oil and gas production are potentially hazardous, difficult and costly to rectify, and damaging to the environment; a high degree of reliability over many years of continuous operation is therefore an essential requirement of subsea systems. Although technical issues have been widely investigated, less is known about the organizational factors that promote high reliability in the design, manufacture, and installation of these systems. This review draws on studies of high‐reliability manufacturing and process industries to examine the roles of intraorganizational factors (particularly organizational culture) that may promote or detract from the achievement of high reliability in subsea systems. External factors, such as supply chain coordination, are also considered. Studies of organizational change designed to enhance the reliability of design and manufacturing processes are rare in the subsea industry, but relevant issues arising from change initiatives in other organizational settings are discussed. Finally, several areas are identified in which systematic industry‐based research could contribute to identifying critical elements in the development and operation of subsea systems and, hence, reduce the risk of failures. © 2011 Wiley Periodicals, Inc.