bluuebunny/crossref_metadata_2025 huggingface dataset:
Process Improvement, Learning, and Real Options
Authors: Li George , Rajagopalan Sampath
Published: December 2008

We use a real‐options approach to analyze investments in process improvement. We develop a simple, stochastic model of a firm making investment decisions in process improvement. Our analysis offers several interesting insights into investments in process improvement. First, early investment in process improvement results in valuable knowledge, which helps increase the value of the option to invest in process improvement in future periods. This may motivate a firm to invest in process improvements as early as possible. Second, it may be optimal for a firm to stop investing when such investments do not create enough value in the later stages of the investment horizon. Third, although one would expect the state of a firm's process relative to that of other firms to impact a firm's decision to invest in process improvement, this study finds that the impetus is conditional and identifies these conditions. Finally, in such an environment, the delay of investment in process improvement incurs an opportunity cost for a firm, and we show that the traditional net present value rule must incorporate this opportunity cost and the knowledge‐induced change in future option values to lead to a correct investment decision.
Scheduling Support Times for Satellites with Overlapping Visibilities
Authors: Arkali Gökçen , Dawande Milind , Sriskandarajah Chelliah
Published: December 2008

We consider the scheduling of ground station support times to low Earth orbit (LEO) satellites with overlapping visibilities. LEO satellites typically complete a revolution around the Earth in less than four hours at an altitude of a few hundred miles and are part of the critical infrastructure for natural resource management, crop yield estimation, meteorology, flood control, communication, and space research. Because these satellites are quite expensive to launch and operate, utilizing them in the best possible manner is of paramount importance for the agencies that own them. A ground station provides support time to a satellite to perform a variety of tasks when the satellite is visible to the station over a prespecified planning horizon; the payoff from providing such support is a function of the support time. When two or more satellites pass over the ground station, their visibility time windows may overlap. Thus, under overlapping visibilities, a relevant problem is that of scheduling ground station support time for each satellite with the objective of maximizing the total utility generated from supporting the satellites. We propose four basic scheduling models to address a variety of scenarios and investigate their computational complexities. For each model, we also identify special cases that are polynomially solvable.
From Mass Production to Mass Customization: Hindrance Factors, Structural Inertia, and Transition Hazard
Authors: Rungtusanatham M. Johnny , Salvador Fabrizio
Published: December 2008

Research on mass customization has largely overlooked the issue of organizational change associated with the mass production‐to‐mass customization transition. To address this gap in the literature, we conduct a longitudinal case study of a manufacturing facility belonging to a division of a Fortune 1000 discrete manufacturing firm as it seeks to transition from mass production to mass customization. We empirically identify five factors hindering the mass production‐to‐mass customization transition within the research site and articulate five corresponding generalizations explaining how and why these hindrance factors relate to the mass production‐to‐mass customization transition hazard beyond the research site (i.e., how and why the five hindrance factors, in general, threaten the likelihood of a successful mass production‐to‐mass customization transition). We then theoretically validate the five hindrance factors and corresponding generalizations by mapping them onto the antecedents and tenets of structural inertia theory. We conclude with a brief discussion of the scientific and pragmatic significance of the findings and highlight opportunities for future research.
Product Design for Life‐Cycle Mismatch
Authors: Bradley James R. , Guerrero Héctor H.
Published: December 2008

L ife‐cycle mismatch occurs when the life cycle of a product does not coincide with the life cycles of the parts used in that product. This is particularly a problem with products that contain electronic components that sometimes have life spans of only two years. The cost of mitigating component obsolescence, which may require redesigning the product, is often considerable. Thus, prudent product design necessitates the selection of electronic components and product architecture, considering the cost of mitigating an obsolete design and other costs related to the design and manufacture of a product. Accordingly, we develop and analyze a model that shows how a product design can be effectively tailored to a particular product's life cycle.
The Effects of Sharing Upstream Information on Product Rollover
Authors: Li Zhaolin , Gao Long
Published: December 2008

The process of introducing new and phasing out old products is called product rollover. This paper considers a periodic‐review inventory system consisting of a manufacturer and a retailer, where the manufacturer introduces new and improved products over an infinite planning horizon using the solo‐roll strategy. We consider two scenarios: (1) the manufacturer does not share the upstream information about new‐product introduction with the retailer and (2) the manufacturer shares the information. For each scenario, we first derive the decentralized ordering policy and the system‐optimal ordering policy with given cost parameters. We then devise an optimal supply chain contract that coordinates the inventory system. We demonstrate that when the inventory system is coordinated, information sharing improves the performance of both supply chain entities. However, this may not be true if the inventory system is not coordinated. We also show that under the optimal contract, the manufacturer has no incentive to mislead the retailer about new‐product information in the information‐sharing model. When demand variability increases, information sharing adds more benefits to the coordinated supply chain. Our research provides insights about coordinating product, financial, and information flows in supply chains with product rollover.
On the Benefits of Assortment‐Based Cooperation Among Independent Producers
Authors: Akçay Yalçin , Tan Bariş
Published: December 2008

Motivated by the challenges small‐ to medium‐size companies face in export‐oriented industries, we consider a competitive market for a set of substitutable products. Depending on the assortment of the firms and the substitution behavior of the customer, either a product is sold to the customer or the sale is lost. We consider the cooperation of independent producers that offer a combined set of products to their customers. Producers use discounted price contracts to manage the exchange of products among themselves. We propose an analytical model that enables us to determine the characteristics of firms and their products that would facilitate a beneficial cooperation. We conclude that a cooperation between symmetric single‐product firms is always beneficial, whereas threshold‐type criteria should be satisfied so that assortment‐based cooperation is beneficial for asymmetric firms. We also show that commonality in product assortments of cooperating firms has adverse effects on the benefit from cooperation. For the most general problem setting, we propose a method to determine the set of firms that should cooperate and set the parameters of the contract among the members of cooperation in such a way that each member of the cooperation is better off. We use a numerical study to draw insights on the conditions for which our cooperation scheme is beneficial in the most general problem setting.
Value of Sharing Production Yield Information in a Serial Supply Chain
Authors: Choi Hyun‐cheol Paul , Blocher James D. , Gavirneni Srinagesh
Published: December 2008

New developments in corporate information technology such as enterprise resource planning systems have significantly increased the flow of information among members of supply chains. However, the benefits of sharing information can vary depending on the supply chain structure and its operational characteristics. Most of the existing research has studied the impact of sharing downstream information (e.g., a manufacturer sharing information with its suppliers). We evaluate the benefits of sharing upstream yield information (e.g., a supplier sharing information with the manufacturer) in a two‐stage serial supply chain in which the supplier has multiple internal processes and is faced with uncertain output due to yield losses. We are interested in determining when the sharing of the supplier's information is most beneficial to the manufacturer. After proposing an order‐up‐to type heuristic policy, we perform a detailed computational study and observe that this information is most beneficial when the supplier's yield variance is high and when end‐customer demand variance is low. We also find that the manufacturer's backorder‐to‐holding cost ratio has little, if any, impact on the usefulness of information.
Effectiveness of stone treatments in enhancing the durability of bioclastic calcarenite in (Granada, Spain)
Authors: Luque A. , Cultrone G. , Sebastián E. , Cazalla O.
Published: December 2008

Santa Pudia limestone, a biocalcarenite highly sensitive to decay, is one of the most commonly used building materials in historical monuments in the city of Granada, Spain. The compatibility between a variety of stone treatments (consolidants and/or water repellents) and this calcarenite was analyzed and the resulting improvement in durability assessed. To this end, a two-stage accelerated ageing process was implemented. In the first, freshly quarried, undamaged specimens were altered to resemble the weathered stone in buildings. The second was conducted after applying the various treatments to the artificially aged stone to test their effectiveness. While all the treatments studied (Tegosivin HL100, Silo 111, Estel 1100 and Tegovakon V) enhanced stone resistance to decay while barely affecting chromatic parameters, the most effective was Tegowakon V, as it provided the best results in the hydric tests on the limestone.
A MOBILE-CARE SYSTEM OVER WIRELESS SENSOR NETWORK FOR HOME HEALTHCARE APPLICATIONS
Authors: Lee Ren-Guey , Lai Chien-Chih , Chiang Shao-Shan , Liu Hsin-Sheng , Chen Chun-Chang , Hsieh Guan-Yu
Published: December 2008

In response to the home healthcare requirement of chronic patients, this paper proposes a mobile-care system integrated with a variety of vital-sign monitorings, where all the front-end vital-sign measuring devices are portable and have the ability of short-range wireless communication. In order to make the system suitable for home applications, wireless sensor network is introduced to transmit the captured vital signs to the residential gateway by means of multi-hop relay. Then the residential gateway uploads data to the care server via internet to carry out patient's condition monitoring and the management of pathological data. Furthermore, the system is equipped with the alarm mechanism, where the portable care device is able to immediately perceive the critical condition of the patient and send a warning message to medical and nursing personnels to achieve the goal of prompt rescue.
THE EFFECTS OF PEDAL RATES ON PEDAL REACTION FORCES DURING ELLIPTICAL EXERCISE
Authors: Chien Hui-Lien , Tsai Tsung-Yuan , Lu Tung-Wu
Published: December 2008

Despite the growing popularity in recent years of elliptical exercise (EE), little is known regarding the loadings applied to the body during EE. Since overloading to the body may lead to early fatigue of the muscles and increase the incidence of overuse injuries, such information is necessary for safe use of the elliptical trainer (ET) as a fitness tool. The current study aimed to determine the typical patterns and loading rates of the measured pedal reaction forces (PRF), and to quantify their differences from those during level walking, and the effects of pedaling rate. Fifteen male adults performed level walking and EE while 3D marker data, right PRFs and ground reaction forces (GRF) were measured. The parameters of the ET were set for two different pedal rates: 50 rpm and 70 rpm. For each pedal rate, the parameters were set to match the variables measured during level walking, with a mean step length of 55% leg length and no workload. During early stance the vertical PRF was smaller than the GRF, while the medial and posterior PRF were greater. PRFs also occurred during swing. Loading rates around heelstrike during EE were all smaller than those during walking. The medial, anterior and posterior PRF, as well as the medial and vertial loading rates increased with increasing pedal rates. The basic force patterns of EE and the effects of pedal rate were established in order to determine the true potential for such instrumentation in locomotion analysis. The results will be helpful for future related studies.
GRAY RELATIONAL ALGORITHM FOR ECG PATTERN RECOGNITION
Authors: Wen Cheng , Huang Chih-Hung , Yeh Ming-Feng
Published: December 2008

The paper proposes a gray relational analysis based learning algorithm, called gray relational algorithm, for the recognition of ECG beats. Without analyzing relations between the input ECG beat and every beat in the database for the recognition, several training beats are chosen for learning from an ECG waveform database with patient diagnosis information, and then the learning result is used to analyze the test ECGs. The resulting similarity measurement is further identified as the diagnosis of the test ECG. This algorithm is capable of reducing the computational procedure of gray relational analysis as it is directly used for the analysis. The experiment shows that the proposed method can achieve a good classification result.
DEVELOPMENT OF A WEB-BASED FETAL MONITORING SYSTEM: AN INNOVATIVE APPROACH
Authors: Mittra A. K. , Choudhary N. K.
Published: December 2008

The well being of the fetal is one of the primary issues in prenatal obstetric care. The assessment of fetal well being is usually practiced by observing the fetal heart rate and monitoring its patterns. Ultrasound based instruments are commonly used for this purpose in hospitals, but they are not suitable for home monitoring applications because of several known reasons. This work is focused around the development of a web-based prototype system for routine fetal home monitoring application. This is helpful in management of complex pregnancies. The presented system is used for recording fetal heart sound in the woman's restful hours at home and makes it available to the physician remotely via the internet. Transmitted data is then processed by an innovative methodology for deriving crucial results of diagnostic importance. After careful examination of these results, status report is electronically e-mailed to the expectant mother for a ready reference and subsequent action. The system has been tested on 20 pregnant women with varied gestation age and pathological conditions. The resultant performance was compared with a standard ultrasound based device commonly used in hospitals. It is found that the developed fetal health care system provides promising result that enables fetal monitoring in low stress, and relaxed home environment. It also supports rapid information flow, and provides quick accessibility to information at the point of decision.
Hole Injection in a Model Fluorene–Triarylamine Copolymer
Authors: Fong Hon Hang , Papadimitratos Alexis , Hwang Jaehyung , Kahn Antoine , Malliaras George G.
Published: December 2008

Recent developments in synthesis and purification have yielded conjugated polymers with hole mobilities exceeding 0.01 cm2 V−1 s−1. Essential to harvesting the potential of these materials in organic light emitting diodes (OLEDs) is the identification of suitable ohmic contacts. Using a model fluorene copolymer that shows high‐mobility, non‐dispersive hole transport, it is demonstrated that electrodes commonly used as anodes in OLEDs are very poor hole injectors. Injection from Au and indium tin oxide anodes is limited by energy barriers of 0.75 and 0.65 eV, respectively, and the injected current is found to be temperature independent—a prediction that was not reproduced by the leading injection model for disordered organic semiconductors. Injection from a poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) anode, on the other hand, is found to become less efficient with electric field, a behavior which is currently not understood. In thinner poly[(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐co‐(4,4′‐(N‐(4‐sec‐butyl))diphenylamine)] films, which are of relevance to OLEDs, ohmic losses on the PEDOT:PSS layer are found to limit the flow of current. These results illustrate the opportunity to further improve the performance of OLEDs as well as the challenge posed by high mobility conjugated polymers for the design of hole injection layers.
Enzyme‐Mediated Deposition of a TiO2 Coating onto Biofunctionalized WS2 Chalcogenide Nanotubes
Authors: Tahir Muhammad Nawaz , Natalio Filipe , Therese Helen Annal , Yella Aswani , Metz Nadine , Shah Muhammad Raza , Mugnaioli Enrico , Berger Rüdiger , Theato Patrick , Schröder Heinz‐Christoph , Müller Werner E. G. , Tremel Wolfgang
Published: December 2008

A chemically specific and facile method for the biofunctionalization of WS2 nanotubes (NT‐WS2) is reported. The covalent modification strategy is based on the affinity of the nitrilotriacetic acid (NTA) side chain, which serves as a ligand for the surface binding to NT‐WS2 and simultaneously as an anchor group for the binding of His‐tagged proteins to the polymer backbone. The polymer functionalized WS2 nanotubes can be solubilized either in water or organic solvents; they are stable for at least one week. The probes were characterized by FT‐IR and UV‐vis spectroscopy. The immobilization of silicatein, a hydrolytic protein encountered in marine sponges, was visualized by scanning force microscopy (SFM) and confocal laser scanning microscopy (CLSM). The formation of the biotitania coating mediated by the immobilized silicatein onto the surface was characterized by scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
Bioinspired Design of SrAl2O4:Eu2+Phosphor
Authors: Kostova Mariya H. , Zollfrank Cordt , Batentschuk Miroslaw , Goetz‐Neunhoeffer Friedlinde , Winnacker Albrecht , Greil Peter
Published: December 2008

A phosphor based on Sr0.97Al2O4:Eu0.03with a biomorphous morphology is manufactured via vacuum assisted infiltration of wood tissue (Pinus sylvestris) with a precursor nitrate solution. The nitrate solution penetrates homogeneously into the uniform arrangement of rectangular shaped tracheidal cells of the wood tissue. According to scanning electron microscopy, the original wood cell walls are completely transformed retaining the original wood structure. The major crystalline phase is monoclinic SrAl2O4, detected by X‐ray diffraction and confirmed by Rietveld refinement. Energy‐dispersive X‐ray analysis proves the homogeneous conversion of the original wood cell wall into Sr0.97Al2O4:Eu0.03struts. The optical properties of the resulting phosphor material are determined by photoluminescence and cathode‐luminescence spectroscopy in scanning electron microscopy. The biotemplated Sr0.97Al2O4:Eu0.03shows a characteristic green emission at 530 nm (2.34 eV). Shaping biomorphous SrAl2O4:Eu2+phosphor with a microstructure pseudomorphous to the bioorganic template anatomy offers a novel approach for designing micropatterned phosphor materials.
A Densely and Uniformly Packed Organic Semiconductor Based on Annelated β‐Trithiophenes for High‐Performance Thin Film Transistors
Authors: Tan Lin , Zhang Lei , Jiang Xi , Yang Xiaodi , Wang Linjun , Wang Zhaohui , Li Liqiang , Hu Wenping , Shuai Zhigang , Li Lin , Zhu Daoben
Published: December 2008

A novel semiconductor based on annelated β‐trithiophenes is presented, possessing an extraordinary compressed packing mode combining edge‐to‐face π–π interactions and S…S interactions in single crystals, which is favorable for more effective charge transporting. Accordingly, the device incorporating this semiconductor shows remarkably high charge carrier mobility, as high as 0.89 cm2 V−1 s−1, and an on/off ratio of 4.6 × 107 for vacuum‐deposited thin films.
Nanoaggregate‐Embedded Beads as Novel Raman Labels for Biodetection
Authors: Huang Ping‐Ji , Chau Lai‐Kwan , Yang Tzyy‐Schiuan , Tay Li‐Lin , Lin Tai‐Tsung
Published: December 2008

Novel Raman tags called nanoaggregate‐embedded beads (NAEBs) have been developed. NAEBs are silica‐coated, dye‐induced aggregates of a small number of metal nanoparticles. In this work, the Raman reporters used to induce aggregation of gold nanoparticles include strongly binding dyes such as XRITC, TRITC, and DTDC and weakly binding dyes such as R6G. Surface‐enhanced Raman scattering (SERS) signal from a single NAEB can be detected. This study also demonstrates that these SERS‐active beads can be used as Raman tags for bio‐detection.
Preparation of Functional Hybrid Glass Material from Platinum (II) Complexes for Broadband Nonlinear Absorption of Light
Authors: Zieba Roman , Desroches Cédric , Chaput Frédéric , Carlsson Marcus , Eliasson Bertil , Lopes Cesar , Lindgren Mikael , Parola Stephane
Published: December 2008

The synthesis of trans‐di(arylalkynyl)diphosphine platinum(II) complexes bearing trialkoxysilane groups is described, as well as the preparation of siloxane‐based hybrid materials from organometallic chromophores through a modified sol–gel process. Glass materials prepared from trans‐[P(n–Bu)3]2Pt[(C≡C–p–C6H4–C≡C–p–C6H4–CH2O(CO)NH(CH2)3Si(OC2H5)3]2 generally show spectral transmittance, absorption and luminescence similar to that of solutions reported in the literature. Measurements of optical power limiting for the hybrid glass are carried out, and show broadband nonlinear absorption throughout the whole visible wavelength range with clamping values in the range 0.2–7 µJ at 120 mM chromophore concentration. The sol–gel process using urethane‐propyltriethoxysilane‐functionalized chromophores as precursors appears to be a valid method for formation of robust silicate materials with grafted diarylethynyl Pt(II) complexes for OPL devices.
π‐Conjugated Oligothiophene‐Based Polycatenar Liquid Crystals: Self‐Organization and Photoconductive, Luminescent, and Redox Properties
Authors: Yasuda Takuma , Ooi Hirotaka , Morita Jun , Akama Yusuke , Minoura Kiyoshi , Funahashi Masahiro , Shimomura Takeshi , Kato Takashi
Published: December 2008

A series of liquid‐crystalline (LC) π‐‐conjugated oligothiophenes bearing three or two alkoxy chains at their extremities has been designed and synthesized. These polycatenar oligothiophenes form various LC nanostructures including smectic, columnar, and micellar cubic phases. These properties depend on the number and length of the terminal alkoxy chains. The hole mobilities for the oligothiophenes have been measured. The layered smectic and columnar structures are capable of transporting holes, leading to mobilities of up to 0.01 cm2 V−1 s−1. The columnar LC assemblies have also been explored to produce linearly polarized light‐emission. Fine red polarized fluorescence is observed from a uniaxially aligned film of the oligothiophenes. The redox properties of the oligothiophenes both in solutions and in films have been examined. The oligothiophenes exhibit electrochromism upon applying an oxidative potential. The present design strategy is useful for fabricating a variety of functional electro‐active molecular assemblies.
p‐Toluenesulfonylmethyl Isocyanide (TosMIC) and Indium Manifold Strategy to Access β‐Keto‐(E)‐enamino Esters from 1,3‐Dicarbonyl Compounds
Authors: Krishna Palakodety Radha , Sekhar Empati Raja
Published: December 2008

The indium trichloride‐catalyzed CC bond formation between 1,3‐dicarbonyl compounds and p‐toluenesulfonylmethyl isocyanide (TosMIC) to access β‐keto‐(E)‐enamino esters exclusively is reported for the first time. The corresponding products are obtained in good to excellent yields.
Aerobic Oxidative Iodination of Organic Compounds with Iodide Catalyzed by Sodium Nitrite
Authors: Stavber Gaj , Iskra Jernej , Zupan Marko , Stavber Stojan
Published: December 2008

Selective and efficient iodinations of organic compounds were achieved by an aerobic oxidative process catalyzed by sodium nitrite using potassium iodide in acidic media. Using the potasasium iodide (KI)/air/sodium nitrite (NaNO2; cat.)/sulfuric acid (H2SO4) iodinating system, activated and moderately deactivated aromatic compounds were exclusively or preferentially iodinated at the para position. In protic solvents ketones and 1,3‐dicarbonyl compounds were iodofunctionalized at the α carbonyl position, while in the case of aryl methyl ketones bearing an activated aromatic ring, the regioselectivity of iodination could be directed by the solvent used. In acetonitrile (MeCN) the aromatic ring was selectively iodinated, while in aqueous rethanol (EtOH) functionalization of the methyl carbon atom took place. Alkenes were transformed to vicinal iodohydrins or vicinal iodoalkoxy derivatives following Markovnikov‐type regioselectivity and anti stereoselectivity, while 1,2‐diiodoalkenes with preferentially E orientation were formed from alkynes.
Supported Palladium Catalysts for Suzuki Reactions: Structure‐Property Relationships, Optimized Reaction Protocol and Control of Palladium Leaching
Authors: Köhler Klaus , Heidenreich Roland G. , Soomro Saeeda S. , Pröckl Sandra S.
Published: December 2008

Palladium on metal oxides and on activated carbon with particular properties (high palladium dispersion, low degree of reduction, water content) are shown to be highly active (tunrover number, TON=20,000; turnover frequency, TOF=16,600), selective and robust catalysts for Suzuki cross‐couplings of aryl bromides and activated aryl chlorides. Catalysts and reaction protocol offer combined advantages of high catalytic efficiency under ambient conditions (air and moisture), easy separation and reuse and quantitative recovery of palladium. The palladium concentration in solution during the reaction correlates clearly with the progress of the reaction and indicates that dissolved molecular palladium is in fact the catalytically active species. Dissolved palladium is redeposited onto the support at the end of the reaction. Additional minimization of the palladium content in solution (down to 0.1 ppm) could be achieved by simple procedures which meet the requirements of pharmaceutical industry.
Palladium‐Catalyzed N‐Demethylation/N‐Acylation of Some Morphine and Tropane Alkaloids
Authors: Carroll Robert J. , Leisch Hannes , Scocchera Eric , Hudlicky Tomas , Cox D. Phillip
Published: December 2008

Hydrocodone was converted to various N‐acyl derivatives via a one‐pot N‐demethylation/N‐acylation protocol catalyzed by palladium(II). The procedure has also been successfully applied to several N‐methyltropane alkaloids. A plausible mechanism is suggested.
Epistaxis in a low level hydrogen fluoride exposed industrial staff
Authors: Graff Pål , Bozhkov Georgi , Hedenlöf Karin , Johannesson Olof , Flodin Ulf
Published: December 2008

Objectives

To assess the effect of exposure to hydrogen fluoride (HF) on the airway mucosa in an industrial setting.

Methods

A cross‐sectional study encompassing 33 industrial workers in a flame soldering plant and 44 assembly workers unexposed to HF was performed by means of a questionnaire on symptoms and diagnosis regarding upper and lower airways as well as through conduct of a clinical examination of the exposed group. Air concentrations of HF that were monitored in winter amounted to 1.0 mg/m3 and in summer time to 0.15 mg/m3.

Results

A threefold risk for epistaxis (RR = 3.6, 95% confidence interval 1.1–11.0) was observed in the exposed group. Time from the start of exposure to HF until debut of a nose bleeding period varied from 1 month to 6 years. Mean induction (latency) time was 42 months. Mean duration of symptoms was 26 months, range 3–72 months, indicating that the exposure level in summer time was sufficient to maintain the propensity of almost daily nose bleeding.

Conclusion

HF is an irritating vapor, even at relatively low air concentrations. We recommend an 8 hr TLV lower than 1.0 mg/m3. Am. J. Ind. Med. 52:240–245, 2009. © 2008 Wiley‐Liss, Inc.
Orale Verabreichung von Protein‐ und Peptidwirkstoffen entlang der Vitamin‐B12‐Route
Authors: Petrus Amanda K. , Fairchild Timothy J. , Doyle Robert P.
Published: December 2008

Der oralen Verabreichung therapeutischer Peptide und Proteine stehen zwei größere Hindernisse entgegen: der proteolytische Abbau im Magen und ein unzulänglicher Absorptionsmechanismus für Polypeptide aus dem Darmlumen. Daher müssen Therapeutika auf Proteinbasis über Injektionen verabreicht werden – ein schmerzhafter Vorgang, der auf geringere Zustimmung beim Patienten stößt. Daher war es das Ziel umfangreicher Forschungsarbeiten, diese beiden Hindernisse zu überwinden und die erfolgreiche orale Verabreichung von Peptidtherapeutika zu ermöglichen. Dieser Kurzaufsatz konzentriert sich auf die orale Peptid/Protein‐Verabreichung über den bestehenden Aufnahmeweg für Vitamin B12 aus der Nahrung. Aktuelle Fortschritte auf diesem Gebiet schließen die Verabreichung von Erythropoietin, des Granulocyten stimulierenden Faktors, des Luteinisierungshormon freisetzenden Hormons und von Insulin ein.
Chemoselektive Ligations‐ und Modifikationsstrategien für Peptide und Proteine
Authors: Hackenberger Christian P. R. , Schwarzer Dirk
Published: December 2008

Die Untersuchung biologischer Fragestellungen mit chemischen Methoden wird meist als “Chemische Biologie” bezeichnet und setzt voraus, dass biologisch relevante Makromoleküle, wie Peptide und Proteine, chemisch zugänglich sind. Auf der Festphasensynthese von Peptiden aufbauend wurden viele chemoselektive Ligations‐ und Modifikationstechniken zur Verknüpfung synthetischer Peptide oder funktionaler Einheiten zu größeren synthetischen, biologisch relevanten Makromolekülen entwickelt. Dieser Aufsatz fasst die aktuellen Entwicklungen auf dem Gebiet der chemoselektiven Ligations‐ und Modifikationsstrategien zusammen und illustriert ihre Anwendbarkeit an Beispielen aus der chemischen Totalsynthese von Proteinen bis hin zur Semisynthese natürlicher modifizierter Proteine.
Solid‐State Scrolls from Hierarchical Self‐Assembly of T‐Shaped Rod–Coil Molecules
Authors: Hong Dong‐Je , Lee Eunji , Jeong Haemi , Lee Jeong‐kyu , Zin Wang‐Cheol , Nguyen Trung Dac , Glotzer Sharon C. , Lee Myongsoo
Published: December 2008

Aufgerollt wie ein Teppich: Durch Anbringen flexibler Knäuel an den Mittelteil starrer stabförmiger Moleküle entstehen T‐förmige Stab‐Knäuel‐Konstrukte, die selbstorganisierte Schichten aufbauen. Diese Schichten rollen sich auf, sodass im Festkörper, je nach Größe der Knäuel, ausgefüllte Zylinder oder hohle Röhren resultieren (siehe Bild). Die Stäbe liegen dabei jeweils in der Schichtebene.

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Heterogeneously Hybridized Porous Coordination Polymer Crystals: Fabrication of Heterometallic Core–Shell Single Crystals with an In‐Plane Rotational Epitaxial Relationship
Authors: Furukawa Shuhei , Hirai Kenji , Nakagawa Keiji , Takashima Yohei , Matsuda Ryotaro , Tsuruoka Takaaki , Kondo Mio , Haruki Rie , Tanaka Daisuke , Sakamoto Hirotoshi , Shimomura Satoru , Sakata Osami , Kitagawa Susumu
Published: December 2008

MOF on MOF: Core–shell porous coordination polymer (PCP) crystals are fabricated at the single‐crystal level by epitaxial growth in solution. Synchrotron X‐ray diffraction measurements unveiled the structural relationship between the shell crystal and the core crystal, where in‐plane rotational epitaxial growth compensates the difference in lattice constant.

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Synthesis and Anticonvulsant Activity of N‐(2‐Hydroxy‐ethyl)amide Derivatives
Authors: Guan Li‐Ping , Zhao Dong‐Hai , Xiu Jing‐Hui , Sui Xin , Piao Hu‐Ri , Quan Zhe‐Shan
Published: December 2008

A series novel of N‐(2‐hydroxyethyl)amide derivatives was synthesized and screened for their anticonvulsant activities by the maximal electroshock (MES) test, and their neurotoxicity was evaluated by the rotarod test (Tox). The maximal electroshock test showed that N‐(2‐hydroxyethyl)decanamide 1g, N‐(2‐hydroxyethyl)palmitamide 1l, and N‐(2‐hydroxyeth‐yl)stearamide 1n were found to show a better anticonvulsant activity and also had lower toxicity than the marked anti‐epileptic drug valproate. In the anti‐MES potency test, these compounds exhibited median effective doses (ED50) of 22.0, 23.3, 20.5 mg/kg, respectively, and median toxicity doses (TD50) of 599.8, >1000, >1000 mg/kg, respectively, resulting in a protective index (PI) of 27.5, >42.9, >48.8, respectively. This is a much better protective index than that of the marked anti‐epileptic drug valproate (PI = 1.6). To further investigate the effects of the anticonvulsant activity in several different models, compounds 1g, 1l, and 1n were tested having evoked convulsions with chemical substances, including pentylenetetrazloe, isoniazide, 3‐mercaptopropionic acid, bicuculline, thiosemicarbazide, and strychnine.
π‐Conjugated Dendrimers as Stable Pure‐Blue Emissive Materials: Photophysical, Electrochemical, and Electroluminescent Properties
Authors: Jiang Yang , Wang Lei , Zhou Yan , Cui Yu‐Xin , Wang Jian , Cao Yong , Pei Jian
Published: December 2008

Bigger, stronger, better: A family of giant π‐conjugated dendrimers has been developed as pure‐blue active materials for organic light‐emitting diodes. The dendrimer‐generation number has little effect on the photophysical, electrochemical, and EL properties, and device efficiency of G0 and G1. The preliminary OLED devices achieve pure‐blue color with stable CIE chromaticity coordinates (0.16, 0.08) for both G0 and G1.

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A family of giant π‐conjugated dendrimers has been developed as pure‐blue active materials for organic light‐emitting diodes (OLEDs). The investigation of their photophysical properties indicates that G0 and G1 exhibit almost the same absorption and PL spectra in dilute solutions and in thin films. The steric hindrance of the bulky dendrimers effectively prevents strong intermolecular interaction in the solid state, which effectively improves the emission spectral stability. Preliminary OLEDs fabricated with the configuration of ITO/PEDOT:PSS/PVK/dendrimer/TPBI/Ba/Al achieve a pure‐blue emission with stable CIE chromaticity coordinates (0.16, 0.08) for both G0 and G1. These results indicate that G0 and G1 are promising blue‐light emitting materials with good stability. Such strategy provides us a platform to achieve pure‐blue emitting dendrimer‐like materials with high efficiency for use as OLEDs.
Asymmetric Syntheses and Wnt Signal Inhibitory Activity of Melleumin A and Four Analogues of Melleumins A and B
Authors: Luo Jie‐Min , Dai Chao‐Feng , Lin Shu‐Yong , Huang Pei‐Qiang
Published: December 2008

Guided by nature: A flexible and epimerization‐free approach for the asymmetric syntheses of melleumin A and four analogues of melleumins A and B was developed, which allowed confirming the stereochemistry at C‐4 of melleumin A, and revealed that the unnatural 4‐epi‐melleumin B possesses a modest inhibitory activity on Wnt signaling.

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The first total synthesis of melleumin A and four analogues of melleumins A and B is described. The N‐acyl L‐Thr‐Gly/β‐hydroxy‐γ‐amino acid coupling/macrolactamization strategy allowed the efficient assembly of the three segments being free of epimerization. While the Jouin–Castro method with minor modification allows a rapid entrance to the key syn‐β‐hydroxy‐γ‐amino acid segment, required for the synthesis of melleumin A, an extension of our malimide‐based methodology using a changed N‐protecting group affords a flexible access to several anti‐β‐hydroxy‐γ‐amino acids, and hence analogues of melleumins A and B. Among them, unnatural 4‐epi‐melleumin B (2 a) exhibits a modest inhibitory activity on Wnt signaling. The total synthesis of melleumin A allowed confirmation of its full structure.
High‐Temperature Chlorination‐Reduction Sequence for the Preparation of Silicon Hydride Modified Silica Surfaces
Authors: Plumeré Nicolas , Speiser Bernd , Mayer Hermann A. , Joosten Dominik , Wesemann Lars
Published: December 2008

A general method for the functionalization of silica surfaces with silicon hydride (Si–H) groups is described for four different preparations of silica. The silica surface is reduced in a two‐step chlorination–reduction procedure within a simple gas‐flow system at high temperatures. After initial dehydroxylation of the silica surface, silicon chloride groups are formed by the reaction with thionyl chloride. The chlorination activates otherwise inaccessible surface siloxane moieties. A high silicon–hydride surface concentration results from the subsequent reduction of the chlorinated surface with hydrogen. The physical properties of the resulting silica are analyzed using scanning electron microscopy, as well as dynamic light scattering and Brunauer–Emmet–Teller measurements. The chlorination–reduction sequence has no significant impact on the structure, surface area and mesopore size of the silica materials used. The surface of the materials is characterized by diffuse reflectance infrared Fourier transform (DRIFT) and 29Si CP/MAS NMR spectroscopy. The silicon–hydride groups are mostly of the ${{\rm T}{{3\hfill \atop {\rm H}\hfill}}}$‐type. The use of high temperatures (>800 °C) results in the condensation of internal and surface silanol groups. Therefore, materials with both a fully condensed silica matrix as well as a surface free of silanol groups are obtained. The materials are ideal precursors for further molecular silica surface modification, as demonstrated with a ferrocene derivative.
Chirality in the Absence of Rigid Stereogenic Elements: The Design of Configurationally Stable C3‐Symmetric Propellers
Authors: Benincori Tiziana , Marchesi Andrea , Pilati Tullio , Ponti Alessandro , Rizzo Simona , Sannicolò Francesco
Published: December 2008

Residual stereoisomerism is a form of stereoisomerism scarcely considered so far for applicative purposes, though extremely interesting, since the production of stereoisomers does not involve classical rigid stereogenic elements. In three‐bladed propeller‐shaped molecules, a preferred stereomerization mechanism, related to the correlated rotation of the rings, allows the free interconversion of stereoisomers inside separated sets (the residual stereoisomers) that can interconvert through higher energy pathways. In light of possible future applications as chiral ligands for transition metals in stereoselective processes, some C3‐symmetric phosphorus‐centered propellers, which could exist as residual enantiomers, are synthesized and the possibility of resolving their racemates into residual antipodes is explored. While the tris(aryl)methanes are configurationally stable at room temperature, only selected tris(aryl)phosphane oxides display a configurational stability high enough to allow resolution by HPLC on a chiral stationary phase (CSP HPLC) at a semipreparative level at room temperature. Stability was evaluated through different techniques (circular dichroism (CD) signal decay, dynamic CSP HPLC (CSP DHPLC), dynamic NMR analysis (DNMR)) and the results compared and discussed. Phosphanes were found much less stable than the corresponding phosphane oxides, for which preliminary calculations suggest that the three‐ring‐flip enantiomerization mechanism (M0) would be easier than phosphorus pyramidal inversion. The parameters affecting the configurational stability of the residual enantiomers of C3‐symmetric propellers are discussed.
Lewis Acid or Brønsted Acid Catalyzed Reactions of Vinylidene Cyclopropanes with Activated Carbon–Nitrogen, Nitrogen–Nitrogen, and Iodine–Nitrogen Double‐Bond‐Containing Compounds
Authors: Lu Jian‐Mei , Zhu Zhi‐Bin , Shi Min
Published: December 2008

Lewis acid or Brønsted acid catalyzed reactions of vinylidene cyclopropanes (VDCPs), 1, with activated carbon–nitrogen, nitrogen–nitrogen, and iodine–nitrogen double‐bond‐containing compounds have been thoroughly investigated. We found that pyrrolidine and 1,2,3,4‐tetrahydroquinoline derivatives can be formed in good yields in the reactions of VDCPs 1 with ethyl (arylimino)acetates 2 by a [3+2] cycloaddition or intramolecular Friedel–Crafts reaction pathway. Based on these results, we found that activated carbon–nitrogen and nitrogen–nitrogen double‐bond‐containing compounds, such as N‐toluene‐4‐sulfonyl (N‐Ts) imines 5 and diisopropylazodicarboxylate (7), can also react with VDCPs 1 to give [3+2] cycloaddition products in moderate to good yields in the presence of a Lewis acid. When N‐tert‐butoxycarbonyl aldimine 9 was used as the substrate, six‐membered cycloaddition products 10 and 11 were formed in moderate yields in the presence of a Brønsted acid, trifluoromethanesulfonic acid (TfOH). The reactions of VDCPs 1 with N‐Ts‐iminophenyliodinane (12) were also carried out in the presence of (CuOTf)2⋅C6H6 and it was found that nitrogen‐containing indene derivatives 13 were obtained, rather than the aziridination products. Plausible mechanisms for all of these transformations are discussed, based on the obtained results.
Complexation between Methyl Viologen (Paraquat) Bis(Hexafluorophosphate) and Dibenzo[24]Crown‐8 Revisited
Authors: Gasa Travis B. , Spruell Jason M. , Dichtel William R. , Sørensen Thomas J. , Philp Douglas , Stoddart J. Fraser , Kuzmič Petr
Published: December 2008

Paraquat bis(hexafluorophosphate) undergoes stepwise dissociation in acetone. All three species—the neutral molecule, and the mono‐ and dications—are represented significantly under the experimental conditions typically used in host–guest binding studies. Paraquat forms at least four host–guest complexes with dibenzo[24]crown‐8. They are characterized by both 1:1 and 1:2 stoichiometries, and an overall charge of either zero (neutral molecule) or one (monocation). The monocationic 1:1 host–guest complex is the most abundant species under typical (0.5–20 mM) experimental conditions. The presence of the dicationic 1:1 host–guest complex cannot be excluded on the basis of our experimental data, but neither is it unambiguously confirmed to be present. The two confirmed forms of paraquat that do undergo complexation—the neutral molecule and the monocation—exhibit approximately identical binding affinities toward dibenzo[24]crown‐8. Thus, the relative abundance of neutral, singly, and doubly charged pseudorotaxanes is identical to the relative abundance of neutral, singly, and doubly charged paraquat unbound with respect to the crown ether in acetone. In the specific case of paraquat/dibenzo[24]crown‐8, ion‐pairing does not contribute to host–guest complex formation, as has been suggested previously in the literature.
ChemInform Abstract: Mg2Cl‐5 and Mg3Cl‐7 Superhalogen Anions.
Authors: Anusiewicz Iwona
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Co2As2O5 — The First Cobalt(II)—Arsenate(III).
Authors: Loesel Stefan , Hillebrecht Harald
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: BaIrIn4 and Ba2Ir4In13: Two In‐Rich Polar Intermetallic Structures with Different Augmented Prismatic Environments about the Cations.
Authors: Palasyuk Andriy M. , Corbett John D.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Controlled Synthesis and Optical Properties of Colloidal Ternary Chalcogenide CuInS2 Nanocrystals.
Authors: Zhong Haizheng , Zhou Yi , Ye Mingfu , He Youjun , Ye Jianping , He Chang , Yang Chunhe , Li Yongfang
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electronic Structure and Physical Properties of Hf5Sb9 Containing a Unique T Net of Sb Atoms.
Authors: Xu Jianxiao , Kleinke Katja M. , Kleinke Holger
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Strontium Isopoly Tungstates: Synthesis and Properties.
Authors: Rozantsev G. M. , Radio S. V. , Gumerova N. I.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ln‐Site Substitution Effect on the Oxygen‐Storage Capability of LnBaCo4O7+δ.
Authors: Kadota S. , Karppinen M. , Motohashi T. , Yamauchi H.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Solid‐ and Solution Phase Transformations in Novel Hybrid Iodoplumbate Derivatives Templated by Solvated Yttrium Complexes.
Authors: Mishra Shashank , Jeanneau Erwann , Daniele Stephane , Ledoux Gilles , Swamy Prakash N.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Microporous Vanadyl‐Arsenate with the Template Incorporated Exhibiting Sorption and Catalytic Properties.
Authors: Berrocal Teresa , Mesa Jose L. , Pizarro Jose L. , Bazan Begona , Iglesias Marta , Aguayo Andres T. , Arriortua Maria I. , Rojo Teofilo
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Transition of Classic Decatungstate to Paratungstate: Synthesis, Structure and Luminescence Properties of Two Paratungstate‐Based 3‐D Compounds.
Authors: Yuan Ling , Qin Chao , Wang Xinlong , Li Yangguang , Wang Enbo
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.