bluuebunny/crossref_metadata_2025 huggingface dataset:
Los proyectos de integración social del indio y el imaginario nacional de las elites intelectuales guatemaltecas, siglos XIX y XX
Authors: Casaus Arzú Marta E.
Published: October 2010

En este artículo se exponen con cierto rigor las tesis de algunos de los pensadores políticos del siglo XIX y XX, en torno a los proyectos de nación incluyentes o excluyentes de los grupos subalternos, indios o ladinos.
Se analizan a lo largo del siglo XIX las posiciones más incluyentes, representadas por José Cecilio del Valle, o las excluyentes, Batres Jáuregui y se analiza el proceso por el cual estas tesis siguen perdurando hasta el momento actual.
Se pueden encontrar defensores de la exclusión en Horacio Altamirano o de la inclusión, Juárez Muñoz, durante el primer cuarto del siglo XX.
El análisis de algunos pensadores de la llamada Generación del 20 permea todo este artículo y representa un novedoso análisis y una veta de trabajo realmente importante para comprender cuáles han sido algunos de aquellos argumentos que se siguen utilizando incluso en el presente, para seguir sosteniendo las teorías de la exclusión o inclusión de los indígenas en el proyecto de nación guatemalteco.
Effects of Orientation and Weatherproofing on the Detection of Bat Echolocation Calls
Authors: Britzke Eric R. , Slack Brooke A. , Armstrong Mike P. , Loeb Susan C.
Published: October 2010

Ultrasonic detectors are powerful tools for the study of bat ecology. Many options are available for deploying acoustic detectors including various weatherproofing designs and microphone orientations, but the impacts of these options on the quantity and quality of the bat calls that are recorded are unknown. We compared the impacts of three microphone orientations (horizontal, 45°, and vertical) and two weatherproofing designs (polyvinyl chloride tubes and the BatHat) on the number of calls detected, call quality, and species detected by the Anabat II bat detector system at 17 sites in central Kentucky in May and June 2008. Detectors with BatHat weatherproofing recorded significantly fewer call sequences, pulses per file, species per site, and lower quality calls. Detectors in the horizontal position also tended to record fewer files, fewer species, and lower quality calls. These results illustrate potential impacts of deployment method on quality and quantity of data obtained. Because weatherproofing and orientation impacted the quality and quantity of data recorded, comparison of results using different methodologies should be made with caution.
Microangiopathic Anemia of Acute Brucellosis – is it a True TTP?
Authors: Kuperman Amir
Published: October 2010

Thrombotic thrombocytopenic purpura (TTP) is a severe disease, potentially fatal, if not diagnosed and treated promptly. TTP is clinically characterized by the pentad of thrombocytopenia, Coombs-negative hemolytic anemia, fever, renal abnormalities and neurological disturbances. Advances in recent years have delineated the molecular mechanisms of acquired and hereditary TTP.Many infectious organisms have been reported to be associated with TTP, especially mycoplasma, but only 6 cases of Brucella infection associated with thrombotic microangiopathy were reported.We describe a young woman who presented clinically with TTP following acute infection with both Brucella melitensis and Brucella abortus. The patient completely recovered after an aggressive therapy with plasmapharesis, high-dose corticosteroids and appropriate antimicrobial therapy.Since measurement of ADMTS13 activity and neutralizing antibodies is now available, and in none of the reported cases of brucellosis with thrombotic microangiopathy (including the present report) were tested, we recommend this work-up in future cases for better understanding of this rare association.
A triad of pastoral leadership for congregational health and well-being: Leader, manager and servant in a shared and equipping ministry
Authors: Manala Matsobane J.
Published: October 2010

That ministry is to be given back to the laity is a laudable proposition. However, the level of development in many township and village communities is still such that a strong leadership and management facilitation role is demanded of the pastor. In such contexts, the pastor is also the only one who is always available for church tasks. The point of departure of this article was that the pastor is primarily a facilitator who assumes the tasks of a leader, a manager and a servant. The Trinitarian office of Christ is taken as model. Christian leadership, as discussed from a systems perspective, is seen as enabling rather than hegemonic. The pastor fulfils the seven leadership functions in order to equip the saints for their Christian service. Church management is redefined as a process which takes place in meaningful collaboration with others, over against the objectification found in conventional definitions which focus on ‘getting things done through people’. This article discussed servant leadership and service provision as the central purpose of Christian leadership.
Lessons Learned from Implementation of Information and Communication Technologies in Spain’s Healthcare Services
Authors: Rojas D. , Carnicero J.
Published: October 2010

Background: Spain’s health services have undertaken a number of important projects aimed at the creation of Electronic Health Records (EHR) through the incorporation of Information and Communication Technologies (ICT) into patient care practices. The objective of this endeavor is to improve care quality and efficiency and increase responsiveness to the population‘s needs and demands. Between 2006-2009 over 300 million Euro were invested in projects of this type.

Objective: To better understand the success criteria, the difficulties encountered and certain issues that must be kept in mind to ensure successful implementation of ICT projects in health organizations, based on Spain‘s experiences in this field.

Methods: The projects’ results are analyzed using the criteria of compliance with the expected scope, cost and time frame.

Results: The results can be considered satisfactory in primary care facilities, where almost 90% of Spain‘s general practitioners, pediatricians and primary care nurses are using electronic health record (EHR) systems. In hospitals EHR implementation is more uneven. Over 40% of Spanish primary care centers and 42% of pharmacies are using electronic prescription (the information system that connects the physician to the dispensing pharmacy and the dispensing pharmacy to the payer).

Discussion: All of Spain’s health services are currently carrying out projects involving ICT application in healthcare, and a priori the benefits of ICT are not questioned. However, the costs and time frames required for these projects are clearly surpassing initial expectations, while the benefits perceived by both professionals and institutions remain limited. This situation may be due in part to the absence of a project management culture in the health services, which has led them to pay insufficient attention to the main difficulties and key issues related to the implementation of EHR.
What is the Role of Three-dimensional Ultrasound in Reproductive Medicine?
Authors: Lam Po Mui , Haines Christopher
Published: October 2010

This article reviews the merits of three-dimensional (3D) ultrasound and thereby establishes its clinical and research role in reproductive medicine. Its main clinical applications include the assessment for uterine anomalies and intrauterine pathology, especially, if combined with the procedure of saline infusion into the uterine cavity. Moreover, 3D color Doppler sonography is an exciting research tool for the evaluation of endometrial receptivity, ovarian reserve, and polycystic ovaries.
Three-dimensional Sonography in the Assessment of Normal Fetal Anatomy in Late Pregnancy
Authors: Ahmed Badreldeen , Honemeyer Ulrich
Published: October 2010

Three-dimensional, multiplanar sonography, using a volume data set acquired with a 3D probe, has revolutionized ultrasonographic imaging and takes sonographers to a new perception of the fetus in 3 dimensions. Real time scanning, until the late nineties only possible in B-mode, can now be performed in 3D with up to 40 frames/sec. Fetal neurology emerged as a new perinatal research field with the 4D visualization of fetal behavior. Doppler ultrasound, diversified and refined from continuous wave and pulsed Doppler to Color – and Power Doppler, when added to 3D sonography, creates fascinating options of noninvasive fetal vascular mapping (sonoangiography) and vascular assessment of placenta. The diagnostic and demonstrative potential of an acquired 3D volume data set can be maxed with the help of postprocessing and rendering software. After storage, the evaluation of fetal 3D data sets can happen without the patient, with the option of specialist consultation, using telemedicine. In the article, the new 3D “modes” like surface rendering, maximum mode, 3D Color and Power Doppler, STIC, volume rendering, and glass body rendering, are described and illustrated in their display of normal fetal anatomy.
Soot microphysical effects on liquid clouds, a multi-model investigation
Authors: Koch D. , Balkanski Y. , Bauer S. E. , Easter R. C. , Ferrachat S. , Ghan S. J. , Hoose C. , Iversen T. , Kirkevåg A. , Kristjansson J. E. , Liu X. , Lohmann U. , Menon S. , Quaas J. , Schulz M. , Seland Ø. , Takemura T. , Yan N.
Published: October 2010

Abstract. We use global models to explore the microphysical effects of carbonaceous aerosols on clouds. Although absorption of solar radiation by soot warms the atmosphere, soot may cause climate cooling due to its contribution to cloud condensation nuclei (CCN) and therefore cloud brightness. Six global models conducted three soot experiments; four of the models had detailed aerosol microphysical schemes. The average cloud radiative response to biofuel soot (black and organic carbon), including both indirect and semi-direct effects, is −0.11 Wm−2, comparable in size but opposite in sign to the respective direct effect. In a more idealized fossil fuel black carbon experiment, some models calculated a~positive cloud response because soot provides a deposition sink for sulfuric and nitric acids and secondary organics, decreasing nucleation and evolution of viable CCN. Biofuel soot particles were also typically assumed to be larger and more hygroscopic than for fossil fuel soot and therefore caused more negative forcing, as also found in previous studies. Diesel soot (black and organic carbon) experiments had relatively smaller cloud impacts with five of the models
The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate
Authors: Reed J. M. , Cvetkoska A. , Levkov Z. , Vogel H. , Wagner B.
Published: October 2010

Abstract. Lake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the Last Glacial, while setting up taxonomic protocols for future research. The results are outstanding in demonstrating the sensitivity of diatoms to climate change, providing proxy evidence for temperature change marked by glacial-interglacial shifts between the dominant planktonic taxa, Cyclotella fottii and C. ocellata, and exact correlation with geochemical proxies to mark the start of the Last Interglacial at ca. 130 ka. Importantly, diatoms show much stronger evidence in this site for warming during MIS3 than recorded in other productivity-related proxies, peaking at ca. 39 ka, prior to the extreme conditions of the Last Glacial maximum. In the light of the observed patterns, and from the results of analysis of early Holocene sediments from a second core, Lz1120, the lack of a response to Late Glacial and early Holocene warming from ca. 14.7–6.9 ka suggests the Co1202 sequence may be compromised during this phase. After ca. 7.4 ka, there is evidence for enhanced nutrient enrichment compared to the Last Interglacial, followed by a post-Medieval loss of diversity which is consistent with cooling, but not definitive. Taxonomically, morphological variability in C. fottii shows no clear trends linked to climate, but an intriguing change in central area morphology occurs after ca. 48.7 ka, coincident with a tephra layer. In contrast, C. ocellata shows morphological variation in the number of ocelli between interglacials, suggesting climatically-forced variation or evolutionary selection pressure. The application of a simple dissolution index does not track preservation quality very effectively, underlining the importance of diatom accumulation data in future studies.
Methane oxidation in permeable sediments at hydrocarbon seeps in the Santa Barbara Channel, California
Authors: Treude T. , Ziebis W.
Published: October 2010

Abstract. A shallow-water area in the Santa Barbara Channel, California, known collectively as the Coal Oil Point seep field, is one of the largest natural submarine hydrocarbon emission areas in the world. Both gas and oil are seeping constantly through a predominantly sandy seabed into the ocean. This study focused on the methanotrophic activity within the surface sediments (0–15 cm) of the permeable seabed in the so-called Brian Seep area at a water depth of ∼10 m. Detailed investigations of the sediment biogeochemistry of active gas vents indicated that it is driven by fast advective transport of water through the sands, resulting in a deep penetration of oxidants (oxygen, sulfate). Maxima of microbial methane consumption were found at the sediment-water interface and in deeper layers of the sediment, representing either aerobic or anaerobic oxidation of methane, respectively. Methane consumption was relatively low (0.6–8.7 mmol m−2 d-1) in comparison to gas hydrate-bearing fine-grained sediments on the continental shelf. The low rates and the observation of free gas migrating through permeable coastal sediments indicate that a substantial proportion of methane can escape the microbial methane filter in coastal sediments.
Late Quaternary palaeoenvironmental reconstruction from Lakes Ohrid and Prespa (Macedonia/Albania border) using stable isotopes
Authors: Leng M. J. , Baneschi I. , Zanchetta G. , Jex C. N. , Wagner B. , Vogel H.
Published: October 2010

Abstract. Here we present stable isotope data from three sediment records from lakes that lie along the Macedonian-Albanian border (Lake Prespa: 1 core, and Lake Ohrid: 2 cores). The records only overlap for the last 40 kyr, although the longest record contains the MIS 5/6 transition (Lake Ohrid). The sedimentary characteristics of both lakes differ significantly between the glacial and interglacial phases. At the end of MIS 6 Lake Ohrid's water level was low (high δ18Ocalcite) and, although productivity was increasing (high calcite content), the carbon supply was mainly from inorganic catchment rock sources (high δ13Ccarb). During the last interglacial, calcite and TOC production and preservation increased, progressively lower δ18Ocalcite suggest increase in humidity and lake levels until around 115 ka. During ca. 80 ka to 11 ka the lake records suggest cold conditions as indicated by negligible calcite precipitation and low organic matter content. In Lake Ohrid, δ13Corg are complacent; in contrast, Lake Prespa shows consistently higher δ13Corg suggesting a low oxidation of 13C-depleted organic matter in agreement with a general deterioration of climate conditions during the glacial. From 15 ka to the onset of the Holocene, calcite and TOC begin to increase, suggesting lake levels were probably low (high δ18Ocalcite). In the Holocene (11 ka to present) enhanced productivity is manifested by high calcite and organic matter content. All three cores show an early Holocene characterised by low δ18Ocalcite, apart from the very early Holocene phase in Prespa where the lowest δ18Ocalcite occurs at ca. 7.5 ka, suggesting a phase of higher lake level only in (the more sensitive) Lake Prespa. From 6 ka, δ18Ocalcite suggest progressive aridification, in agreement with many other records in the Mediterranean, although the uppermost sediments in one core records low δ18Ocalcite which we interpret as a result of human activity. Overall, the isotope data present here confirm that these two big lakes have captured the large scale, low frequency palaeoclimate variation that is seen in Mediterranean lakes, although in detail there is much palaeoclimate information that could be gained, especially small scale, high frequency differences between this region and the Mediterranean.
Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model
Authors: Atencia A. , Llasat M. C. , Garrote L. , Mediero L.
Published: October 2010

Abstract. The performance of distributed hydrological models depends on the resolution, both spatial and temporal, of the rainfall surface data introduced. The estimation of quantitative precipitation from meteorological radar or satellite can improve hydrological model results, thanks to an indirect estimation at higher spatial and temporal resolution. In this work, composed radar data from a network of three C-band radars, with 6-minutal temporal and 2 × 2 km2 spatial resolution, provided by the Catalan Meteorological Service, is used to feed the RIBS distributed hydrological model. A Window Probability Matching Method (gage-adjustment method) is applied to four cases of heavy rainfall to improve the observed rainfall sub-estimation in both convective and stratiform Z/R relations used over Catalonia. Once the rainfall field has been adequately obtained, an advection correction, based on cross-correlation between two consecutive images, was introduced to get several time resolutions from 1 min to 30 min. Each different resolution is treated as an independent event, resulting in a probable range of input rainfall data. This ensemble of rainfall data is used, together with other sources of uncertainty, such as the initial basin state or the accuracy of discharge measurements, to calibrate the RIBS model using probabilistic methodology. A sensitivity analysis of time resolutions was implemented by comparing the various results with real values from stream-flow measurement stations.
Using structural information to improve search in Web collections
Authors: de Moura Edleno S. , Fernandes David , Ribeiro‐Neto Berthier , da Silva Altigran S. , Gonçalves Marcos André
Published: October 2010

In this work, we investigate the problem of using the block structure of Web pages to improve ranking results. Starting with basic intuitions provided by the concepts of term frequency (TF) and inverse document frequency (IDF), we propose nine block‐weight functions to distinguish the impact of term occurrences inside page blocks, instead of inside whole pages. These are then used to compute a modified BM25 ranking function. Using four distinct Web collections, we ran extensive experiments to compare our block‐weight ranking formulas with two other baselines: (a) a BM25 ranking applied to full pages, and (b) a BM25 ranking that takes into account best blocks. Our methods suggest that our block‐weighting ranking method is superior to all baselines across all collections we used and that average gain in precision figures from 5 to 20% are generated.
Augmented Lyapunov functional approach for stability of neutral systems with mixed delays
Authors: Qian Wei , Liu Juan , Fei Shumin
Published: October 2010

This paper is concerned with the neutral‐delay‐dependent and discrete‐delay‐dependent stability for uncertain neutral systems with mixed delays and norm‐bounded uncertainties. Through constructing a new augmented Lyapunov‐Krasovskii functional and proving its positive definiteness, introducing some slack matrices and using integral inequality, the improved delay‐dependent stability criteria are derived in terms of linear matrix inequalities. Numerical examples are given to illustrate the significant improvement on the conservatism of the delay bound over some existing results.

Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Das essenzielle Spurenelement Zink. Ein Metall in Biologie und Medizin
Authors: Haase Hajo , Rink Lothar
Published: October 2010

Der menschliche Körper enthält 2–3 Gramm des essenziellen Spurenelements Zink. Sowohl die Aufnahme als auch die Ausscheidung von Zink unterliegen einer genauen Kontrolle. Wenn dieses Gleichgewicht gestört ist, kommt es zu einer Beeinträchtigung zahlreicher biologischer Vorgänge: Zink ist unter anderem wichtig für die Entwicklung und Funktion des zentralen Nervensystems, die Infektabwehr des Immunsystems und die Produktion und Funktion von Insulin. In der Zelle gibt es über 300 zinkhaltige Enzyme, viele weitere Zinkproteine sowie freies Zink, das eine Rolle bei der Weiterleitung von Signalen innerhalb der Zelle spielt.
Flechten. Der Erfolg einer Symbiose
Authors: Büdel Burkhard
Published: October 2010

Flechten sind eine einzigartige Gruppe von Organismen, die je aus einer oder zwei Algen und einem Pilz bestehen. Der Thallus ist artspezifisch und wird nur in der Symbiose verwirklicht. Aufgrund ihrer ökologischen Eigenschaften können sie nahezu alle terrestrischen Habitate besiedeln. Ihre poikilohydrische Natur hat aber auch Nachteile. Sie können ihren Wasserhaushalt nicht kontrollieren und werden deshalb oft mit Wasser übersättigt. Auch wenn alle anderen Umweltfaktoren optimal sind, wird ihr Kohlenstoffgewinn so deutlich reduziert. Diese Eigenschaften setzen den Rahmen innerhalb dessen der Thallusbau für ein bestimmtes Mikroklima variiert werden kann. Da jede Optimierung hinsichtlich der Wasseraufnahme auch für die Wasserabgabe gilt, vollführen Flechten immer eine Gradwanderung zwischen zu viel oder zu wenig Wasser. Auf diese Weise hat jedes Habitat seine eigene Herausforderung an die Thalluskonstruktion und Flechten müssen “Strategien” parat haben, um mit verschiedenen Umweltbedingungen spezifisch umzugehen.
Wie sich Oasen‐Bananen gegen ihre Feinde wehren. Uralter Toleranzmechanismus im Oman entdeckt
Authors: Bürkert Andreas , Al Khanjari Sulaiman , Al‐Saady Nadiya A. , De Langhe Edmond , Hölscher Dirk , Gebauer Jens , Behrendt Stephan , Happe Stefan , Brinkmann Katja , Schlecht Eva
Published: October 2010

Bis vor wenigen Jahren war über die Kulturpflanzenvielfalt des an der Nordostspitze der arabischen Halbinsel gelegenen Wüstenlandes Oman wenig bekannnt. Neuere interdisziplinäre Untersuchungen in den oft Jahrtausende alten Oasen belegen deren Rolle als genetisches Reservoir für alte, einst aus den Nachbarregionen importierte Weizen‐ und Bananen‐Varietäten. Zwei dieser neu entdeckten Reliktbananen zeigen einen hocheffizienten biochemischen Abwehrmechanismus gegen Schädlinge und Krankheiten, dessen Nutzung für den kommerziellen Anbau von Essbananen große Bedeutung haben könnte.
Drei Höhe(n)punkte am Mittelrhein. Die Exkursion
Authors: Kremer Bruno P.
Published: October 2010

Das Obere Mittelrheintal zwischen Bingen und Koblenz, seit 2002 UNESCO‐Welterbe, ist eine der klassischen Reiselandschaften von beeindruckender landschaftlicher Schönheit. Der steilhängige und enge Canyon weist eine dichte Folge bemerkenswerter Geo‐ und Biotope auf, die sich durch tektonische und floristische ebenso wie faunistische Besonderheiten auszeichnen. Dieser Exkursionsvorschlag greift drei empfehlenswerte Einzelziele heraus.
Geschickte Architektur macht Männchen größer
Authors: Wendler Silke
Published: October 2010

Männliche Laubenvögel sind kunstvolle Architekten. Sie bauen eine Laube mit Wänden aus dünnen Zweigen und Ästen, die sie mit bunten Objekten verzieren, um die Aufmerksamkeit der Weibchen auf sich zu ziehen. Der in Australien beheimatete Graulaubenvogel (Chlamydera nuchalis) bedient sich noch zusätzlich eines optischen Tricks, wodurch er selbst größer und imposanter erscheint.
Henry Moore – Natur und Figur
Authors: Lischka‐Seitz Christiane
Published: October 2010

Mit einer Auswahl von Druckgrafiken, Plastiken und zoologischen Exponaten zeigt die Ausstellung im Neumarkter Museum Lothar Fischer bislang weniger bekannte Aspekte im Werk des berühmten englischen Bildhauers Henry Moore auf.
Diffusion of biologically relevant molecules through gel‐like tissue scaffolds
Authors: Roberts Simon J. , Tomlins Paul E. , Faruqui Nilofar , Robinson Jim A. J.
Published: October 2010

Encapsulation of living cells into gel‐like matrices that are capable of maintaining their viability over an extended time period is starting to play a major role in medicine in applications such as, cell‐based sensors, cellular therapy, and tissue engineering. The permeability of nutrients and waste products through these matrices is critical to their performance. In this article, we report a methodology for selecting scaffolds with different permeabilities and surface area/volume ratios that can be used to house a 3D cell aggregate. Such a system can be modeled if the consumption or production rates for metabolites and waste products, respectively and the diffusion coefficients of these solutes in culture medium and the encapsulating gel matrix are known. A transient finite volume mass diffusion model, based on Fick's law, is derived where the consumption of a solute by the cells is modeled through a source term. The results show that the “performance” of cell‐doped gel is critically dependent on the rate at which cells consume key molecules e.g., glucose. Pragmatically, the model also provides insight as to how many cells a given gel geometry and structure can support. The approach used applies to any porous structure where mass transport occurs through diffusion. © 2011 Crown Copyright Biotechnol. Prog., 2011
A compiler‐based toolkit to teach and learn finite automata
Authors: Chakraborty Pinaki , Saxena P. C. , Katti C. P.
Published: October 2010

This paper introduces a compiler technology based approach to model and simulate finite automata for pedagogical purposes. The compiler technology helps to define a language to formally model finite automata and to develop a toolkit to simulate them efficiently. The language is called Finite Automaton Description Language (FADL) and the toolkit is based on it. A fast single‐pass compiler is used to compile a finite automaton defined in FADL. Then an interpreter is used to simulate the working of the compiled finite automaton for any input string. The nondeterminism of a Nondeterministic Finite Automaton (NFA) is simulated using backtracking. A tool to view the transition diagram of the finite automaton is provided. A Deterministic Finite Automaton (DFA) can be additionally compiled using an optimizing compiler that also minimizes the number of states. Tools for converting an NFA to a DFA and for converting a DFA to a Turing machine are also provided. A preliminary testing of the toolkit has been performed in which the participating students observed that the toolkit is an interesting teaching tool and it helped them to acquire a better perception about finite automata. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 467–474, 2013
Using GEMANOVA to explore the pattern generating properties of the Delta‐Notch model
Authors: Isaeva Julia , Sæbø Solve , Wyller John Andreas , Liland Kristian Hovde , Faergestad Ellen Mosleth , Bro Rasmus , Martens Harald
Published: October 2010

In the area of systems biology, increasingly complex models are developed to approximate biological processes. The complexity makes it difficult to derive the properties of such models analytically. An alternative to analytical considerations is to use multivariate statistical methods to reveal essential properties of the models. In this paper it is shown how the properties of a relatively complex mathematical model for describing cell‐pattern development, the Delta‐Notch model, can be explored by means of statistical analyses of data generated from the model. ANOVA is a well‐known and one of the most commonly used methods for analyzing data from designed experiments, but it turns out that it is not always appropriate for finding and exploring higher‐order interactions. For this purpose a multiplicative alternative—GEMANOVA—was used in the present paper for studying the Delta‐Notch model, for which the properties depend on higher order interactions between the model parameters. It is shown here how a forward selection strategy combined with bootstrapping can be used to identify GEMANOVA models with reasonable fit to the data, and it is demonstrated how new insight about the Delta‐Notch model can be gained from interpreting the GEMANOVA output. Copyright © 2010 John Wiley & Sons, Ltd.
Neutralization of a sec‐Ammonium Group Unusually Stabilized by the “Rotaxane Effect”: Synthesis, Structure, and Dynamic Nature of a “Free” sec‐Amine/Crown Ether‐Type Rotaxane
Authors: Nakazono Kazuko , Takata Toshikazu
Published: October 2010

A fifteen‐year riddle has been settled: neutralization, the most popular chemical event, of a crown ether/sec‐ammonium salt‐type rotaxane has been achieved and a completely nonionic crown ether/sec‐amine‐type rotaxane isolated. A [2]rotaxane was prepared as a typical substrate from a mixture of dibenzo[24]crown‐8 ether (DB24C8) and sec‐ammonium hexafluorophosphate (PF6) with a terminal hydroxy group through end‐capping with 3,5‐dimethylbenzoic anhydride in the presence of tributylphosphane as a catalyst in 90 % yield. A couple of approaches to the neutralization of the ammonium rotaxane were investigated to isolate the free sec‐amine‐type rotaxane by decreasing the degree of thermodynamic and kinetic stabilities. One approach was the counteranion‐exchange method in which the soft counterion PF6− was replaced with the fluoride anion by mixing with tetrabutylammonium fluoride, thus decreasing the cationic character of the ammonium moiety. Subsequent simple washing with a base allowed us to isolate the free sec‐amine‐type rotaxane in a quantitative yield. The other approach was a synthesis based on a protection/deprotection protocol. The acylation of the sec‐ammonium moiety with 2,2,2‐trichloroethyl chloroformate gave an N‐carbamated rotaxane that could be deprotected by treating with zinc in acetic acid to afford the corresponding free sec‐amine‐type rotaxane in a quantitative yield. The structure of the free sec‐amine‐type rotaxane was fully confirmed by spectral and analytical data. The generality of the counteranion‐exchange method was also confirmed through the neutralization of a bisammonium‐type [3]rotaxane. The mechanism was studied from the proposed potential‐energy diagram of the rotaxanes with special emphasis on the role of the PF6− counterion.
Crystallization‐Controlled Dynamic Self‐Assembly and an On/Off Switch for Equilibration Using Boronic Ester Formation
Authors: Takahagi Hiroki , Iwasawa Nobuharu
Published: October 2010

Macrocyclic boronic esters of different sizes can be prepared selectively from the same starting diboronic acid and 1,2‐diol by means of an interesting dynamic self‐assembly phenomena. More specifically, two kinds of macrocyclic boronic esters could be formed diastereoselectively and nearly quantitatively under neutral conditions by the addition of an appropriate guest molecule that acts as a template. Although a mixture of tetrol 1 and di(boronic acid) 2 in methanol gave only insoluble polymeric boronic esters, a soluble macrocyclic boronic ester, homo‐[2+2], was obtained selectively in the presence of toluene as a guest molecule. Furthermore, when benzene was employed as a guest molecule, the selective formation of another macrocyclic boronic ester, hetero‐[3+3], occurred. Interestingly, each of these macrocycles could be converted into the other in the presence of methanol and the appropriate guest molecule; however, under aprotic conditions, guest molecules encaged by the macrocyclic boronic ester could be exchanged without affecting its structure. Thus the presence or absence of a protic solvent could be used as a regulator to switch on or off the dynamic equilibrium of the system. In addition, investigation of the effect of reaction time, direct observation of the reaction mixture by NMR spectroscopy, and carrying out the reaction using optically active tetrol suggested that precipitation plays an essentially important role in the selective formation of the macrocyclic boronic esters. Thus, although both of [2+2] and [3+3] were present as solutes in the reaction mixture, the type of added guest molecule induced the selective precipitation of only one form of macrocyclic boronic ester, hence displacing the equilibrium of the system.
Organocatalysts for the Controlled “Immortal” Ring‐Opening Polymerization of Six‐Membered‐Ring Cyclic Carbonates: A Metal‐Free, Green Process
Authors: Helou Marion , Miserque Olivier , Brusson Jean‐Michel , Carpentier Jean‐François , Guillaume Sophie M.
Published: October 2010

Six‐membered cyclic carbonates, namely trimethylene carbonate (TMC), 3,3‐dimethoxytrimethylene carbonate (DMTMC) and 3‐benzyloxytrimethylene carbonate (BTMC), undergo controlled “immortal” ring‐opening polymerization (iROP) under mild conditions (bulk, 60–150 °C), by using organocatalysts, including an amine [4‐N,N‐dimethylaminopyridine (DMAP)], a guanidine [1,5,7‐triazabicyclo‐[4.4.0]dec‐5‐ene (TBD)], or a phosphazene [2‐tert‐butylimino‐2‐diethylamino‐1,3‐dimethylperhydro‐1,3,2‐diazaphosphorine (BEMP)], in the presence of an alcohol [benzyl alcohol (BnOH), 1,3‐propanediol (PPD), glycerol (GLY)] that acts as both a co‐initiator and a chain‐transfer agent. Remarkably, such organocatalysts remain highly active in the iROP of technical‐grade, unpurified TMC. Under optimized conditions, as much as 100 000 equivalents of TMC were fully converted by as little as 10 ppm of BEMP with the simultaneous growth of as many as 200 polymer chains, allowing the preparation of high molar mass poly(trimethylene carbonate)s (up to 45 800 g mol−1). These catalyst systems enable among the highest activities (TOF=55 800 h−1) and productivities (TON=95 000) ever reported for the ROP of TMC.
X‐ray Fluorescence Investigation of Ordered Intermetallic Phases as Electrocatalysts towards the Oxidation of Small Organic Molecules
Authors: Liu Yi , Lowe Michael A. , Finkelstein Ken D. , Dale Darren S. , DiSalvo Francis J. , Abruña Héctor D.
Published: October 2010

The composition of ordered intermetallic nanoparticles (PtBi and PtPb) has been quantitatively studied by in situ X‐ray fluorescence (XRF) during active electrochemical control in solutions of supporting electrolyte and small organic molecules (SOMs). Because the Pt Lβ1,2 lines and the Bi Lα1,2 lines are only separated by 200 eV, an energy‐dispersive detector and a multiple‐channel analyzer (MCA) were used to record the major fluorescent emission lines from these two elements. The molar ratios of platinum to the less‐noble elements (Bi, Pb) in the nanoparticles dramatically changed as a function of the applied upper limit potentials (Eulp) in cyclic voltammetric (CV) characterization. Similar to previous investigations for bulk intermetallic surfaces, the less‐noble elements leached out from the surfaces of the intermetallic nanoparticles. For PtBi nanoparticles, the ratios of fluorescence intensities of Pt/Bi in the samples were 0.42, 0.96, and 1.36 for Eulp=+0.40, +0.80, and 1.20 V, respectively, while cycling the potential from −0.20 V to the Eulp value for 10 cycles. The leaching‐out process of the less‐noble elements occurred at more negative Eulp values than expected. After cycling to relatively positive Eulp values, nonuniform PtM (M=Bi of Pb) nanoparticles formed with a Pt‐rich shell and intermetallic PtM core. When the supporting solutions contained active fuel molecules in addition to the intermetallic nanoparticles (formic acid for PtBi, formic acid and methanol for PtPb), kinetic stabilization effects were observed for Eulp=+0.80 V, in a way similar to the response of the bulk materials. It was of great importance to quantitatively explore the change in composition and structure of the intermetallic nanoparticles under active electrochemical control. More importantly, this approach represents a simple, universal, and multifunctional method for the study of multi‐element nanoparticles as electrocatalysts. This is, to our knowledge, the first report of nondestructive, quantitative characterization of bimetallic or multi‐elemental nanoparticles electrocatalysts under active electrochemical control.
Short‐Peptide‐Based Hydrogel: A Template for the In Situ Synthesis of Fluorescent Silver Nanoclusters by Using Sunlight
Authors: Adhikari Bimalendu , Banerjee Arindam
Published: October 2010

N‐terminally Fmoc‐protected dipeptide, Fmoc‐Val‐Asp‐OH, forms a transparent, stable hydrogel with a minimum gelation concentration of 0.2 % w/v. The gelation property of the hydrogel was investigated by using methods such as transmission electron microscopy, field‐emission scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy. The silver‐ion‐encapsulating hydrogel can efficiently and spontaneously produce fluorescent silver nanoclusters under sunlight at physiological pH (7.46) by using a green chemistry approach. Interestingly, in the absence of any conventional reducing agent but in the presence of sunlight, silver ions were reduced by the carboxylate group of a gelator peptide that contains an aspartic acid residue. These clusters were investigated by using UV/Vis spectroscopy, photoluminescence spectroscopy, high‐resolution transmission electron microscopy (HR‐TEM), atomic force microscopy (AFM) and X‐ray diffraction (XRD) studies. Mass spectrometric analysis shows the presence of a few atoms in nanoclusters containing only Ag2. The reported fluorescent Ag nanoclusters show excellent optical properties, including a very narrow emission profile and large Stokes shift (>100 nm). The reported fluorescent Ag nanoclusters within hydrogel are very stable even after 6 months storage in the dark at 4 °C. The as‐prepared hydrogel–nanocluster conjugate could have applications in antibacterial preparations, bioimaging and other purposes.
Double‐CO32− Centered [CoII5] Wheel and Modeling of Its Magnetic Properties
Authors: Sarkar Mrinal , Aromí Guillem , Cano Joan , Bertolasi Valerio , Ray Debashis
Published: October 2010

A high‐spin CoII cluster with a rare pentagonal molecular structure and formula [Co5(CO3)2(bpp)5]ClO4 (1; Hbpp is 2,6‐bis(phenyliminomethyl)‐4‐methylphenolate) has been synthesized and characterized by single‐crystal X‐ray diffraction. This topology arises from fusing five [Co2(bpp)] moieties in a cyclic manner around two CO32− central ligands, resulting in propeller‐like configuration. The irregular coordination of the carbonate ions to the metal centers results in a combination of coordination numbers (CNs) of the CoII ions of five and six. The bulk magnetization of this complicated magnetically exchanged system has been modeled successfully by employing a matrix diagonalization technique. For this, the combination of S=3/2 ions (CN=5) with ions exhibiting strong spin‐orbit coupling (CN=6) has been considered and a perturbative approach to handle the data in the whole studied range of temperatures (2–300 K) yielding parameters of g and D (for the five‐coordinate CoII ions), of A, κ, λ, and Δ (for the metals with spin‐orbit coupling) and of the exchange constants J. The agreement with results from DFT calculations, also presented here, is remarkable.
Cyclopropylamines fromN,N‐Dialkylcarboxamides and Grignard Reagents in the Presence of Titanium Tetraisopropoxide or Methyltitanium Triisopropoxide
Authors: de Meijere Armin , Chaplinski Vladimir , Winsel Harald , Kordes Markus , Stecker Björn , Gazizova Vesta , Savchenko Andrei I. , Boese Roland , Schill (née Brackmann) Farina
Published: October 2010

Thirty‐three differentN,N‐dialkyl‐ andN‐alkyl‐N‐phosphorylalkyl‐substituted carboxamides9–17were treated with unsubstituted as well as with 2‐alkyl‐, 2,2‐dialkyl‐, and 3‐alkenyl‐substituted ethylmagnesium bromides6in the presence of stoichiometric amounts of titanium tetraisopropoxide or methyltitanium triisopropoxide to furnish substituted cyclopropylamines20–25in 20–98 % yield, depending on the substituents with no (1:1) to excellent (>25:1) diastereoselectivities. Generally higher yields (up to 98 %) of the cyclopropylamines20–28without loss of the diastereoselectivity were obtained with methyltitanium triisopropoxide as the titanium mediator. Under these conditions, even dioxolane‐protected ketones and halogen‐substituted and chiral as well as achiral alkyloxyalkyl‐substituted carboxamides could be converted to the correspondingly substituted cyclopropylamines with unsubstituted as well as phenyl‐ and a variety of alkyl‐substituted ethylmagnesium bromides in addition to numerous heteroatom‐containing (e.g., halogen‐, trityloxy‐, tetrahydropyranyloxy‐substituted) Grignard reagents (62 examples altogether). The transformation ofN,N‐diformylalkylamines54with ethylmagnesium bromide in the presence of methyltitanium triisopropoxide toN,N‐dicyclopropyl‐N‐alkylamines55can be brought about in up to 82 % yield (6 examples). An asymmetric variant of the titanium‐mediated cyclopropanation ofN,N‐dialkylcarboxamides has been developed by applying chiral titanium mediators generated from stoichiometric amounts of titanium tetraisopropoxide and chiral diamino or diol ligands, respectively. The most efficient chiral mediators turned out to be titanium bistaddolates that provided the corresponding cyclopropylamines with enantiomeric excesses (ee) of up to 84 %. Evaluation of several silyl‐based additives revealed that the reaction can also efficiently be carried out with substoichiometric amounts (down to 25 mol %) of the titanium reagent, as long as 2‐aryl‐ or 2‐ethenyl‐substituted ethylmagnesium halides are used and a concomitant slight decrease in yields is accepted. The newly developed methodology was successfully applied for the preparation of analogues with cyclopropylamine moieties of known drugs and natural products such as the nicotine metabolite (S)‐Cotinine as well as the insecticides Dinotefuran and Imidacloprid.
Smart Macrocyclic Molecules: Induced Fit and Ultrafast Self‐Sorting Inclusion Behavior through Dynamic Covalent Chemistry
Authors: Han Ji‐Min , Pan Jin‐Long , Lei Ting , Liu Chenjiang , Pei Jian
Published: October 2010

A family of macrocycles with oligo(ethylene glycol) chains, 4O, 5O, and 6O, was developed to construct a series of new incorporated macrocycles through dynamic covalent chemistry. These flexible macrocycles exhibited excellent “self‐sorting” abilities with diamine compounds, which depended on the “induced‐fit” rule. For instance, the host macrocycles underwent conformational modulation to accommodate the diamine guests, affording [1+1] intramolecular addition compounds regardless of the flexibility of the diamine. These macrocycles folded themselves to fit various diamines with different chain length through modulation of the flexible polyether chain, and afforded intramolecular condensation products. However, if the chain of the diamine was too long and rigid, oligomers or polymers were obtained from the mixture of the macromolecule and the diamine. All results demonstrated that inclusion compounds involving conformationally suitable aromatic diamines were thermodynamically favorable candidates in the mixture due to the restriction of the macrocycle size. Furthermore, kinetic and thermodynamic studies of self‐sorting behaviors of both mixed 4O–5O and 4O–6O systems were investigated in detail. Finally, theoretical calculations were also employed to further understand such self‐sorting behavior, and indicated that the large enthalpy change of H2NArArNH2@4O is the driving force for the sorting behavior. Our system may provide a model to further understand the principle of biomolecules with high specificity due only to their conformational self‐adjusting ability.
Development of Versatile and Silver‐Free Protocols for Gold(I) Catalysis
Authors: Gaillard Sylvain , Bosson Johann , Ramón Rubén S. , Nun Pierrick , Slawin Alexandra M. Z. , Nolan Steven P.
Published: October 2010

The use of a versatileN‐heterocyclic carbene (NHC) gold(I) hydroxide precatalyst, [Au(OH)(IPr)], (IPr=N,N′‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) permits the in situ generation of the [Au(IPr)]+ion by simple addition of a Brønsted acid. This cationic entity is believed to be the active species in numerous catalytic reactions.1H NMR studies in several solvent media of the in situ generation of this [Au(IPr)]+ion also reveal the formation of a dinuclear gold hydroxide intermediate [{Au(IPr)}2(μ‐OH)], which is fully characterized and was tested in gold(I) catalysis.
Bulk and Surface Structure and High‐Temperature Thermoelectric Properties of Inverse Clathrate‐III in the Si‐P‐Te System
Authors: Zaikina Julia V. , Mori Takao , Kovnir Kirill , Teschner Detre , Senyshyn Anatoliy , Schwarz Ulrich , Grin Yuri , Shevelkov Andrei V.
Published: October 2010

The creation of thermoelectric materials for waste heat recovery and direct solar energy conversion is a challenge that forces the development of compounds that combine appreciable thermoelectric figure‐of‐merit with high thermal and chemical stability. Here we propose a new candidate for high‐temperature thermoelectric materials, the type‐III Si172−xPxTey cationic clathrate, in which the framework is composed of partially ordered silicon and phosphorus atoms, whereas tellurium atoms occupy guest positions. We show that the utmost stability of this clathrate (up to 1500 K) in air is ensured by the formation of a nanosized layer of phosphorus‐doped silica on the surface, which prevents further oxidation and degradation. As‐cast (non‐optimized) Si‐P‐Te clathrates display rather high values of the thermoelectric figure‐of‐merit (ZT=0.24–0.36) in the temperature range of 700–1100 K. These ZT values are comparable to the best values achieved for the properly doped transition‐metal‐oxide materials. The methods of the thermoelectric efficiency optimization are discussed.
Asymmetric reduction of β‐ketoesters and chiral β‐iminoesters: Impact of a α‐quaternary stereocenter
Authors: Almahli Hadia , Hendra Frédéric , Troufflard Claire , Cavé Christian , Joseph Delphine , Delarue‐Cochin Sandrine
Published: October 2010

Diastereomeric reduction of nonactivated, hindered β‐keto and chiral β‐iminoesters are described. The influence of a α‐stereocontrolled center on the efficiency and stereoselectivity of the reduction was studied. Reaction conditions were optimized to synthesize β‐hydroxy‐ and β‐aminoesters in good yields. In the case of chiral β‐iminoesters, influence of matched/mismatched diastereomeric pairs has been assessed. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
A reverse phase HPLC method for the separation of two stereo isomers of 2‐[4‐(methylsulfonyl)phenyl]‐3‐(3(r)‐oxocyclopentyl)propanoic acid
Authors: Davadra Prakash M. , Patel Timir K. , Chauhan Jignesh C. , Kharul Rajendra K. , Pandey Bipin , Jain Mukul R. , Bapodra Atul H.
Published: October 2010

This study describes successful method development and separation of two stereo isomers of 2‐[4‐(methylsulfonyl)phenyl]‐3‐(3(R)‐oxocyclopentyl)propanoic acid by reverse phase high‐performance liquid chromatography. Baseline resolution was achieved on a J'sphere‐ODS‐H80 (150 mm × 4.6 mm, 4 μm) column using mobile phase consisting of 0.05% triflouroacetic acid in water‐acetonitrile (85:15, v/v) at a flow rate of 1.0 ml/min. The detection was carried out at 228 nm. The title compound, in turn, can be obtained by C‐alkylation of methyl 2‐[4‐(methylthio)phenyl]acetate with 2(S)‐iodomethyl‐8,8‐dimethyl‐6,10‐dioxaspiro[4.5]decane followed by consecutive hydrolysis and oxidation. The partially validated analytical method (system suitability, peak homogeneity, linearity, precision, robustness, and solution stability) has limit of detection and limit of quantification, 0.15 and 0.50 μg/ml respectively. Alternatively, the new method is being routinely utilized to monitor epimerization of α‐carbon of the propanoic acid in the title compound by crystallization‐induced dynamic resolution. Chirality, 2011. © 2010 Wiley‐Liss, Inc.