bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐Coordinate Aluminum Amides from Silylanilines and Alkylalanes
Authors: Khandelwal Manish , Powell Douglas R. , Wehmschulte Rudolf J.
Published: December 2010

The aluminum amides R2AlN(Ar)SiMe3 [R = Et, Ar = Dipp, 1 (Dipp = 2,6‐iPr2C6H3‐); R = iBu, Ar = Dipp, 2; R = Et, Ar = Mes, 3 (Mes = 2,4,6‐Me3C6H2‐); R = iBu, Ar = Mes, 4] were prepared by ethane or hydrogen elimination reaction between Et3Al or iBu2AlH and ArN(H)SiMe3 in refluxing hexane solution. The LiCl salt elimination route resulted in the formation of the monomeric aluminum amide Et2AlN(Mes)SiPh3 (5) featuring three‐coordinate aluminum and nitrogen centers. In addition, the synthesis and characterization of the dinuclear species Ph2Si{N(Mes)AlEt2}2 (6) and the hydride‐bridged eight‐membered ring compound {MesN(SiMe3)Al(iBu)(μ‐H)}2(μ‐LiH)(μ‐iBu2AlH) (7) are reported. All compounds have been characterized by 1H and 13C{1H} NMR spectroscopy, and compounds 5, 6, and 7 have also been characterized by single‐crystal X‐ray crystallography.
L‐t‐Leucine‐Catalyzed Direct Asymmetric Aldol Reaction of Cyclic Ketones
Authors: Kanemitsu Takuya , Umehara Atsushi , Miyazaki Michiko , Nagata Kazuhiro , Itoh Takashi
Published: December 2010

L‐t‐Leucine‐catalyzed direct asymmetric aldol reactions are described. In the aldol reaction of p‐nitrobenzaldehyde with a cyclic ketone at room temperature, L‐t‐leucine exhibits catalytic activity resulting in moderate to high diastereo‐ and enantioselectivity. Use of cycloheptanone or cyclooctanone as a substrate resulted in production of the syn selective product.
Nanohybrid Materials as Transducer Surfaces for Electrochemical Sensing Applications
Authors: Pereira da Silva Neves Marta Maria , García María Begoña González , Delerue‐Matos Cristina , García Agustín Costa
Published: December 2010

A nanohybrid electrochemical transducer surface was developed using carbon and gold nanomaterials. The strategy relayed on casting multiwalled carbon nanotubes or carbon nanofibers onto a screen‐printed carbon electrode surface, followed by in situ generation of gold nanoparticles by electrochemical deposition of ionic gold, in a reproducible manner. These transducers, so fabricated, were characterized using both electrochemical and microscopic techniques. Biofunctionality was evaluated using the streptavidin‐biotin interaction system as the biological reaction model. These platforms allow to achieve low detection limits (in the order of pmoles), are reproducible and stable at least for a month after their preparation, being a perfect candidate to be used as transducer of different sensor devices.
Carbon Supported Cobalt and Nickel Based Nanomaterials for Direct Uric Acid Determination
Authors: Singh Baljit , Laffir Fathima , Dickinson Calum , McCormac Timothy , Dempsey Eithne
Published: December 2010

Novel Co‐Ni based catalysts on activated carbon support were prepared using NaBH4 as a reducing agent in aqueous conditions and examined with respect to direct amperometric uric acid detection. The surface morphology and composition of the synthesised materials were examined using transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X‐ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) was employed in order to confirm the typical metallic electrochemical response of the Co, Ni and Co‐Ni based materials. The combination of metal hydroxides/oxides and nanoparticles in the carbon supported Co‐Ni based materials were found to play a key role in uric acid determination. Upon surface confinement of the Co1Ni1/C material, uric acid sensitivity 248.2 µA mM−1 cm−2 and limit of detection 0.08 µM at Eapp=+0.4 V vs. Ag/AgCl was found by hydrodynamic amperometry over the range 0–250 µM (r2=0.9992). The sensor provided linear and reproducible behaviour over a wide range (25–575 µM) of uric acid. The composite materials showed excellent selectivity with respect to commonly found interferences with no response even at 10‐fold concentration of urea, glucose and oxalate, and minimal influence of ascorbic acid (2 fold concentration). Overall, these materials are excellent candidates for direct uric acid detection in a stable, sensitive and very specific fashion over relevant physiological ranges, eliminating the pH, temperature sensitivity and lifetime issues associated with enzyme based systems. The materials are very promising for a range of applications including wound care/management and as non‐enzymatic disposable uric acid test strips.
A Sensitive Glucose Biosensor Based on Brushite, a Biocompatible Cement
Authors: López M. Sánchez‐Paniagua , López‐Ruiz B.
Published: December 2010

A highly sensitive biosensor based on glucose oxidase (GOx) immobilized on brushite cement is described. Biosensor was kept free of the interferences produced by ascorbic and uric acid by placing an extra Nafion film on the surface of the platinum electrode. Variables involved in the enzyme immobilization method were investigated. The biosensor exhibits a rapid response (10 s); a wide linear range (9×10−6 M to 3×10−3 M); low detection limit (9 µM); and high sensitivity (52.5±0.6 mA M−1 cm−2). Nafion/GOx/brushite biosensor was used to monitor the glucose levels of serum samples and satisfactory results were obtained.
Electrochemical Behavior and Electroanalytical Determination of Indole‐3‐Acetic Acid Phytohormone on a Boron‐Doped Diamond Electrode
Authors: Yardım Yavuz , Erez M. Emre
Published: December 2010

In this work, a boron‐doped diamond (BDD) electrode was used for the electroanalytical determination of indole‐3‐acetic acid (IAA) phytohormone by square‐wave voltammetry. IAA yielded a well‐defined voltammetric response at +0.93 V (vs. Ag/AgCl) in Britton–Robinson buffer, pH 2.0. The process could be used to determine IAA in the concentration range of 5.0 to 50.0 µM (n=8, r=0.997), with a detection limit of 1.22 µM. The relative standard deviation of ten measurements was 2.09 % for 20.0 µM IAA. As an example, the practical applicability of BDD electrode was tested with the measurement of IAA in some plant seeds.
A modified measure of health care disparities applied to birth weight disparities and subsequent mortality
Authors: Butler Richard J. , Wilson Barbara L. , Johnson William G.
Published: December 2010

We describe how a modified Gini index serves as an improved method of estimating health care disparities. The method, although general, is applied to an example of birth weight disparities and to their effect on subsequent mortality. The method provides the between‐group results obtainable from current methods (i.e. how Hispanics generally fare relative to non‐Hispanic Whites) but adds measures of within‐group disparities (i.e. which specific Hispanics experience the greatest disparate treatment). Our application to birth weights and receipt of prenatal care, which may provide an upper bound because of omitted variables, shows that the time‐of‐birth disparities are associated with increased infant mortality within the first year of life. Copyright © 2010 John Wiley & Sons, Ltd.
Retained role of surgery for olfactory neuroblastoma
Authors: Smee Robert I. , Broadley Kathryn , Williams Janet R. , Meagher Nicola S. , Bridger G. Patrick
Published: December 2010

Background

Olfactory neuroblastoma is a rare paranasal sinus malignancy. The traditional approach was craniofacial resection (CFR) and then postoperative radiotherapy until 1998. This review will chart development of a new protocol.

Methods

This ethics‐approved audit evaluated the number of new patients diagnosed with olfactory neuroblastoma, with information relating to patient, disease, and treatment factors noted.

Results

There were 24 eligible patients, 16 men, 8 women, 7 Kadish stage B, 17 stage C. The planned treatment was: chemotherapy (cisplatin/etoposide) and determine treatment dependent on response in 6 patients, surgery and radiotherapy in 16 patients, and single‐modality treatment only (surgery, radiotherapy 1) in 2 patients. Surgery to radiotherapy occurred in 17 patients. With salvage treatment ultimate local control was 79%.

Conclusions

There was a higher local control in those patients who had surgery; abandoning this may carry a higher risk of local failure. The use of response to chemotherapy to determine local treatment remains experimental. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Total Synthesis of Aculeatins A and B from L‐Malic Acid
Authors: Yadav Jhillu S. , Rao Yerragorla Gopala , Chandrakanth Dandekar , Ravindar Kontham , Reddy Basi V. Subba
Published: December 2010

An efficient total synthesis of the cytotoxic spiroketal natural products aculeatin A and B is described. The synthesis of the 1,3,5‐triol moiety with appropriate configuration was accomplished from the commercially available L‐malic acid. The key steps in this synthesis are the Barbier allylation, LiAlH4/LiI‐mediated syn‐stereoselective 1,3‐asymmetric reduction, and phenyliodine bis(trifluoroacetate) (=[bis(trifluoroacetoxy)iodo]benzene; PIFA) mediated oxidative spirocyclization.
A Unique Indolo‐[1,7]naphthyridine Alkaloid from Incarvillea mairei var. grandiflora (Wehrh.) Grierson
Authors: Shen Yun‐Heng , Su Yong‐Qing , Tian Jun‐Mian , Lin Sheng , Li Hui‐Liang , Tang Jian , Zhang Wei‐Dong
Published: December 2010

A novel alkaloid with a unique indolo‐[1,7]naphthyridine nucleus, incargranine B, was isolated from the whole plant of Incarvillea mairei var. grandiflora (Wehrh.) Grierson. Its structure was determined by means of spectroscopic methods.
Sesquiterpenoids from Senecio argunensis
Authors: Xie Wei‐Dong , Niu Yu‐Fang , Huang Jian‐Jun , Row Kyung‐Ho
Published: December 2010

Investigation of unpolar extracts from the aerial parts of Senecio argunensis afforded two new sesquiterpenoids, 1β‐hydroxyeudesma‐4,11‐dien‐15‐al (1) and 4(15)‐cadinene‐5α,10α‐diol, (2) as well as six known compounds, 3–8. The structures of all isolates were elucidated on the basis of extensive analyses of spectroscopic data and comparison with literature data.
Neolignans and Caffeoyl Derivatives from Selaginella moellendorffii
Authors: Wang Yue‐Hu , Sun Qian‐Yun , Yang Fu‐Mei , Long Chun‐Lin , Zhao Fu‐Wei , Tang Gui‐Hua , Niu Hong‐Mei , Wang Huan , Huang Qiao‐Qin , Xu Jin‐Jin , Ma Li‐Juan
Published: December 2010

Ten new phenolic compounds including the six neolignans 1–3 and 6–8 and four caffeoyl derivatives, i.e., myo‐inositol 1‐caffeate (9), myo‐inositol 6‐caffeate (10), myo‐inositol 5‐caffeate (11), and paucine 3′‐β‐D‐glucopyranoside (12) were isolated from the whole plants of Selaginella moellendorffii (caffeic acid=3‐(3,4‐dihydroxyphenyl)prop‐2‐enoic acid). Their structures were established by spectroscopic and chemical methods.
Withanolides from Aureliana fasciculata var. fasciculata
Authors: Almeida‐Lafetá Rita C. , Ferreira Marcelo J. P. , Emerenciano Vicente P. , Kaplan Maria A. C.
Published: December 2010

In the first phytochemical study of the Aureliana genus (Solanaceae), two new withanolides, 1 and 2, together with two known sterols, were isolated from the MeOH extract of the leaves of Aureliana fasciculata var. fasciculata. The structures were established as (4S,22R)‐16α‐acetoxy‐5β,6β‐epoxy‐4β,17α‐dihydroxy‐1‐oxowitha‐2,24‐dienolide (aurelianolide A) and (4S,22R)‐16α‐acetoxy‐4β,17α‐dihydroxy‐1‐oxowitha‐2,5,24‐trienolide (aurelianolide B). The new compounds possessed the unusual 16α,17α‐dioxygenated group and were fully characterized by spectroscopic techniques, including 1H‐ and 13C‐NMR (DEPT), as well as 2D‐NMR (HMBC, HMQC, 1H,1H‐COSY, NOESY) experiments, and HR‐MS.
Biologically Active Iridoids from Hedyotis diffusa
Authors: Ding Bo , Ma Wei‐Wei , Dai Yi , Gao Hao , Yu Yang , Tao Ye , Zhong Yi , Yao Xin‐Sheng
Published: December 2010

Two new iridoids, 10‐O‐benzoyl‐6′‐O‐α‐L‐arabino(1→6)‐β‐D‐glucopyranosylgeniposidic acid (1), deacetyl‐6‐ethoxyasperulosidic acid methyl ester (2), along with 14 other known iridoids, were isolated from the whole plant of Hedyotis diffusa Willd. Their structures were determined on the basis of spectroscopic analysis. The short‐term‐memory‐enhancement activities of compounds 1, 7–9, 11, and 13 were evaluated on an Aβ transgenic drosophila model.
Two New Monoterpenes from Mentha haplocalyxBriq.
Authors: She Gaimei , Xu Chao , Liu Bin , Shi Renbing
Published: December 2010

Two new monoterpenes with a skeleton similar to the 1,8‐cineole skeleton, i.e., (1R,4R)‐3,3,5‐trimethyl‐2‐oxabicyclo[2.2.2]oct‐5‐en‐4‐ol (1) and (1R,4R)‐4‐methoxy‐3,3,5‐trimethyl‐2‐oxabicyclo[2.2.2]oct‐5‐ene (2), were isolated from an aqueous acetone extract of the aerial parts of Mentha haplocalyx, together with three known compounds. Their structures were elucidated by extensive spectroscopic methods and by comparison with reference values.
Colorful window dressing: A critical review on workplace diversity in three major American corporations
Authors: Marques Joan F.
Published: December 2010

This article presents a brief diversity audit of three major U.S. corporations, who share some interesting common traits. The attractive diversity delineations posted on these company's Web sites will be reviewed, followed by their issues with the same topic in the past few decades. This threefold audit is followed by two important observations about U.S. and non‐U.S. companies, based on company diversity audits applied over the course of 5 years by more than 150 management university students. The author claims that a large number of major corporations in the United States are going out of their way to post diversity statements on their Web sites and to collect diversity‐based awards from numerous minority‐promoting organizations, but they overlook one small aspect: walking their talk. Theoretical and practical implications for HRD professionals are included.
Examining the role of perceived leader behavior on temporary employees' organizational commitment and citizenship behavior
Authors: Djibo Idriss J. A. , Desiderio Katie P. , Price Noriece M.
Published: December 2010

The attention given to the contingent segment of the workforce has significantly increased over the past decade. Investigative topics include the correlates of temporary employee work attitudes and behaviors. This study used a correlational design to examine leader behaviors outlined by the path–goal theory of leadership, as perceived by temporary employees (N = 126), as a determinant of their organizational commitment and citizenship behaviors. The results indicated that temporary workers' affective commitment was positively related to perceptions of instrumental and supportive leadership. The latter was also significantly related to the participants' organizational citizenship behavior. Implications for both research and practice are discussed.
Investigating the influences of core self‐evaluations, job autonomy, and intrinsic motivation on in‐role job performance
Authors: Joo Baek‐Kyoo (Brian) , Jeung Chang‐Wook , Yoon Hea Jun
Published: December 2010

This study investigates the effects of core self‐evaluations, job autonomy, and intrinsic motivation on employees' perceptions of their in‐role job performance, based on a cross‐sectional survey of 283 employees in a Fortune Global 100 company in Korea. The results suggest that employees perceived higher in‐role job performance when they had higher core self‐evaluations and intrinsic motivation. Intrinsic motivation partially mediated the relationship between core self‐evaluations and job performance, and it also fully mediated the relationship from job autonomy to job performance. Thus, to increase motivation and job performance, managers and HRD professionals need to create an integrated strategy incorporating enhancement of selection methods, elements of job redesign, and interpersonal developmental practices such as coaching and mentoring.
Toward a theoretical model of dispositional influences on transfer of learning: A test of a structural model
Authors: Yamkovenko Bogdan , Holton Ed
Published: December 2010

This study explores the hypothesized relationship between dimensions of the Five Factor model of personality, goal orientation, self‐efficacy, and intent to transfer training on the job. This study attempts to model the complex relationship between these characteristics and intent to transfer using structural equation modeling approach. A set of propositions is presented for each individual variable and its relationship to intent to transfer. Finally, a model of relationships is tested and the results are discussed. The findings revealed that conscientiousness was the only dispositional variable that had a significant relationship to intent to transfer. In addition, control variables, learner readiness and motivation to transfer, were significant in the model. The results suggest that dispositions may not be as important in the transfer system as other constructs like situational, motivational, and ability variables. Recommendations for further research and testing of the model are discussed.
The influence of perceived characteristics of management development programs on employee outcomes
Authors: Ardts Joost C. A. , van der Velde Mandy E. G. , Maurer Todd J.
Published: December 2010

Employees' perceptions of Management Development (MD) programs is the topic of this study. The purpose is to examine the influence of three important perceived characteristics of MD programs on relevant MD outcomes. The MD characteristics are: availability of role models, perceived control, and understanding the MD program. Outcomes are: participation in development activities, MD and job satisfaction, affective organizational commitment, perceived benefits of development activities, average salary growth, innovative behavior, and critical opinion sharing. Data are collected from 453 MD participants of seven organizations in the Netherlands. Findings show that perceived control has a positive relationship with MD satisfaction and extrinsic and organizational benefits of development activities. Understanding the MD program positively influences MD satisfaction and extrinsic benefits. Availability of role models has a positive relationship with intrinsic and organizational benefits.
Stability, change, and the stability of change in daily workplace affect
Authors: Beal Daniel J. , Ghandour Louma
Published: December 2010

Daily affect often is determined by unpredictable events, but also has predictable components. We describe how the simultaneous modeling of overall affect level, cyclical variation in affect, and the occurrence of affective events can provide a clearer understanding of how affective well‐being fluctuates over time. We examined intrinsic task motivation as a positive affective event, and had an opportunity to examine a single large negative affective event as well. Specifically, data collection was interrupted by a hurricane which made landfall very close to the data collection site, disrupting the lives of employees for weeks or months. We hypothesized that affect spin—an individual difference measure of variability in the affect circumplex—would increase reactions both to positive and negative affective events. These ideas were examined with 65 employees who provided daily ratings of affect for 21 days. Positive affect was influenced by several factors, whereas negative affect was less predictable. Affect spin moderated many of the dynamic components of daily positive affect, largely supporting the notion that affect spin reflects sensitivity both to positive and negative affective events. Discussion centers on the utility of incorporating dynamic accounts of affect in the study of well‐being and work. Copyright © 2010 John Wiley & Sons, Ltd.
What makes a creative day? A diary study on the interplay between affect, job stressors, and job control
Authors: Binnewies Carmen , Wörnlein Sarah C.
Published: December 2010

Applying a within‐person perspective to research on creativity at work, this diary study examined daily positive and negative affect (NA) in the morning as well as daily job stressors (time pressure and situational constraints) as predictors of daily creativity. In addition, the general level of job control was investigated as a cross‐level moderator in these relationships. Hypotheses were tested in a sample of 90 interior architects (N = 326 days) who completed a general survey and two daily surveys over the course of one work week. Hierarchical linear modeling showed that a higher level of positive affect (PA) in the morning as well as an intermediate level of daily time pressure was related to higher daily creativity. Job control moderated relations between daily NA, daily situational constraints and daily time pressure (curvilinear effect) with daily creativity. Our results stress the importance of daily affect and daily job stressors as well as the moderating role of job control for daily creativity at work. Copyright © 2010 John Wiley & Sons, Ltd.
p‐Phenylenediamine Epoxy Resin Film for Redox Enzyme Detection
Authors: Kanno Kenichi , Kugimiya Akimitsu , Matsumoto Yasumasa , Konishi Yuya , Arakawa Tsuyoshi , Takaki Yuichiro , Yoshida Yuya , Hanada Keiichiro , Matsumura Kotaro , Endo Takeshi
Published: December 2010

Summary: Phenylenediamine derivatives (PDs) are environmentally hazardous, though very useful for chemical analysis. To minimize release into the environment, a PD‐containing epoxy resin film was developed that retained redox enzyme activity. p‐Phenylenediamine and 2,2‐bis(4‐glycidyloxyphenyl)‐propane were cured to produce a violet film. This film was reactive against peroxidase, a redox enzyme that oxidizes phenylenediamine to afford an imine. Enzymatic oxidation caused the film to change color from violet to deep green. The film exhibited fluorescence at 394 nm under excitation at 350 nm, and the fluorescent intensity decreased with greater oxidation. Thus, the film could be used to detect redox enzyme activity.
Thermosensitive Poly(N‐isopropylacrylamide)‐g ‐Polyamidoamine Dendrimer Derivatives: Preparation and the Drug Release Behaviors
Authors: Wang Zheng , Zhou Bo , Liu Dong , Fan Xiang‐pan
Published: December 2010

Summary: A series of thermally responsive dendritic core‐shell polymers were prepared based upon dendritic polyamidoamine (PAMAM), modified with carboxyl end‐capped linear poly(N‐isopropylacrylamide) (PNIPAAm‐COOH) in different ratios via an esterification process to obtain PNIPAAm‐g‐PAMAM. The graft ratio of PNIPAAm could be adjusted by changing the feed ratio of PAMAM‐OH to PNIPAAm‐COOH and was verified by 1H NMR and gel penetration chromatography (GPC). The lower critical solution temperature (LCST) of PNIPAAm‐g‐PAMAM evaluated by UV‐vis spectrophotometer was about 32 °C. Indomethacin (IMC) as a model drug was loaded in the thermosensitive polymer‐grafted dendrimer derivative and its release behavior was studied below and above its LCST (27 °C vs 37 °C). Results showed that the LCST of PNIPAAm‐g‐PAMAM was around 32 °C compared with that of the pure PNIPAAm. The release behavior of the indomethacin entrapped in the internal cavities of the PNIPAAm‐g‐PAMAM showed that almost 77% of the drug was cumulatively released at 27 °C after 10 hours, whereas only 20% was released at 37 °C. The release rate of IMC from the IMC/PNIPAAm‐g‐PAMAM complex at 37 °C is significantly slower than that at 27 °C, which indicates that the PNIPAAm chains grafted on the surface of PAMAM dendrimer could act as a channel switching on‐off button through expending or contracting in response to the temperature variation and could control the drug release by varying the surrounding temperature.
Tunable Amphiphilic Poly(Ether‐Anhydride) Gel Nanoparticles for the Delivery of Hydrophobic Drugs
Authors: Wang Zheng , Cai Zheng , Guo Qian
Published: December 2010

Summary: Biodegradable amphiphilic poly(ether‐anhydride) gel nanoparticles (GNPs) with a hydrophobic crosslinked core and a hydrophilic PEG shell have been prepared from amphiphilic photo‐crosslinkable ether‐anhydride macromers via microemulsion photo‐polymerization. The properties of the GNPs, such as degradability, size and drug‐loading capacity, were investigated by tailoring the length of PEG chains in macromers from 400 to 4000 and by the addition of a hydrophobic photo‐crosslinkable monomer: stearic monoacrylic anhydride (MSA). TEM showed that the GNPs were spherical in shape with a core‐shell structure when MSA was added. The GNPs were used as the carriers to enhance the solubility of hydrophobic drugs. Indomethacin (IND) as a model drug was entrapped in the hydrophobic crosslinked core by an in situ embedding method. Results showed that IND maintained chemically intact during the formulation process, and its dissolution rate were improved compared to those of the pure IND. The GNPs prepared from PEG macromer (molecular weight: 4000) with the addition of MSA exhibited the zero‐order release behavior, which is potentially useful to control the release of hydrophobic drugs.
Neutral and Charged Brushes Covalently Grafted from OH‐Functionalized Mica Surfaces using Surface‐Initiated ATRP – Swelling Investigation by AFM
Authors: Lego Béatrice , Skene W.G. , Giasson Suzanne
Published: December 2010

Poly(acrylic acid) (PAA) and poly(tert‐butyl acrylate) (PBA) brushes of various grafting densities were prepared via surface‐initiated polymerization of tert‐butyl acrylate on mica. PAA was prepared by hydrolyzing the PBA brushes. The swelling behavior of PBA and PAA brushes was studied as a function of grafting density by AFM. The swelling of the polymer layer was found to be higher for PAA in water than for the PBA sample swollen with DFM.
Simulation of Itraconazole Encapsulation by Novel Biocampatible Dendritic Compounds
Authors: Elkin Igor , Hildgen Patrice
Published: December 2010

Summary: To enhance the dissolution rate of itraconazole, the novel macromolecular biocompatible dendritic compounds were selected. The possible drug encapsulation was evaluated by the calculated difference between potential energies of the individual dendrimers and structures having one itraconazole molecule near the dendrimer core. The structures with the decanediol spacers and with the core presented by 1,2,3,4‐butanetetracarboxylic acid demonstrated better energetic effects to be good candidates as a drug delivery carrier for itraconazole pharmaceutical applications. Additional simulations with the less bulky modeling structures with different cores, using molecular dynamic procedure, allowed us to obtain the best results with the tetracarboxy benzene core.
Polymers Grafted to Single‐walled Carbon Nanotubes by Radical Polymerization
Authors: Ford Warren T.
Published: December 2010

Summary:Polymers have been grafted from single‐walled carbon nanotubes (SWCNT) by ATRP and grafted to SWCNT by use of ATRP and azide end groups and by in situ polymerization. The SWCNT/polymer products are soluble indefinitely in good solvents for the polymers. AFM images indicate that the SWCNT are present as individual or bundles of only a few nanotubes.
Synthesis of Non‐natural Xyloglucans by Polycondensation of 4,6‐Dimethoxy‐1,3,5‐triazin‐2‐yl Oligosaccharide Monomers Catalyzed by Endo‐β‐1,4‐glucanase
Authors: Tanaka Tomonari , Noguchi Masato , Ishihara Masaki , Kobayashi Atsushi , Shoda Shin‐ichiro
Published: December 2010

Summary: A cellotetraose‐backboned hepta‐saccharide (XXXG) (a capital X represents a glucopyranose residue that is substituted with a xylopyranose through an α‐1,6 glycosidic bond, and a capital G represents a non‐substituted glucopyranose residue) and a nona‐saccharide (XLLG) (a capital L represents a glucopyranose residue that is substituted with a galactopyranoseβ(1‐2)xylopyranose through an α‐1,6 glycosidic bond) have directly been converted to the corresponding 4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl derivatives (DMT‐β‐XXXG 1 and DMT‐β‐XLLG 2, respectively) by the action of 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methyl morpholinium chloride (DMT‐MM). The selective nucleophilic attack of the anomeric hydroxyl group to DMT‐MM has been achieved in water without using any protection of the hydroxyl groups. The resulting activated oligosaccharide derivatives (1 and 2) were found to polymerize catalyzed by an endo‐β‐1,4‐glucanase as catalyst. The polymerization took place in a complete regio‐ and stereo‐selective manner, affording non‐natural polysaccharides having a XXXG‐repeating unit and a XLLG‐repeating unit, respectively, in the main chain. It is extremely difficult to construct such definite repeating structures via the conventional synthetic routes including protection‐deprotection procedures.
Chelating Ligands Tethered to Carbon Nanotubes
Authors: Howell Bob A. , Dumitrascu Adina
Published: December 2010

Summary: Carbon nanotubes offer an inert platform on which various species may be supported. A range of applications have been addressed using this approach. Anchoring sites on the nanotubes are usually groups introduced via an oxidative procedure. These groups provide convenient reactive functionality that can be accessed in a variety of ways. In this case, carboxyl functionality have been utilized to attach, through a linker, a good coordinating ligands, 1‐10‐phenanthroline. In the first instance, 1,10‐phenanthroline was converted to the 5,6‐epoxide by treatment with hypochlorite. The epoxide was opened in sulfuric acid to generate the 5‐hydroxy compound. This, in turn, was treated with ethylene oxide in the presence of a base to provide the alkoxylated compound. The alcohol terminus, as the alkoxide, was used to couple the nanotubes by displacement of tosyl anion from the methylol ester. The carboxyl groups at the nanotubes surface were reduced to the corresponding alcohol and treated with p‐toluenesulfonyl chloride in the presence of pyridine to generate the tosylate used for coupling. In a second approach the carboxyl groups were converted to the corresponding acid chloride which was treated with alkoxylated phenanthroline to achieve coupling via an ester linkage.
Synthesis, Characterization and Bactericidal Properties of Poly(N‐vinyl‐2‐pyrrolidone‐co‐Maleic anhydride‐co‐N‐Isopropyl acrylamide)
Authors: Talu Muzaffer , Uzluk Elif , Yüksel Betül
Published: December 2010

Summary: Radical‐initiated terpolymerization of maleic anhydride (MA), N‐vinyl‐2‐pyrrolidone (NVP) with N‐isopyropyl acrylamide (NIPA) has been prepared as a way to obtain new water‐soluble polymers. Structure, composition and thermal behaviour of synthesized terpolymers were determined by FTIR, UV‐vis, 1H NMR spectroscopy, elemental analysis (N content), differential scanning calorimetry, thermogravimetric and differential thermal analysis, gel permeation chromatography analysis (GPC), scanning electron microscopy (SEM) and X‐ray diffraction analysis (XRD). The terpolymer composition‐structure‐property relationship indicates that the semicrystalline structure of terpolymers with different reaction times, degrees of crystallinity, and thermal behaviour depends on the content of carboxyl and amide‐containing monomer linkage. The antimicrobial activities the terpolymers were evaluated against pathogen bacteria: Staphylococcus aureus, Salmonella enteridis, Streptococcucs faecalis, Eschericia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The antimicrobial activity was explored by the well‐diffusion technique. All the studied polymers, containing biologically active moieties in the form of ionized cyclic amide and carboxylic acid groups, were more effective against Gram‐positive than Gram‐negative bacteria. The bactericidal effect of terpolymers against Gram negative bacteria increased with the increasing reaction times.
Micellar Solubilization and In Vitro Release of Silymarin in the self‐Aggregates of an Amphiphilic Derivative of Chitosan
Authors: Sui Weiping , Yin Changqing , Kong Xiangzheng
Published: December 2010

Summary: The amphiphilic derivatives of chitosan, (2‐hydroxyl‐3‐butoxyl)‐propylcarboxymethyl‐chitosan (HBP‐CMCHS), can form micelles with the inner core of hydrophobic segments and the outer shell of hydrophilic segments. The typical poor water‐soluble drug silymarin was solubilized in the HBP‐CMCHS micellar by physical entrapped method. Results showed that the solubilizing capacity was enhanced by increasing the concentration of HBP‐CMCHS with the same dosage of silymarin. Silymarin‐loaded micellar system of HBP‐CMCHS was characterized by TEM and DLS. TEM photograph revealed that the micelles were spherical and silymarin was solubilized in the cores of the spherical polymeric micelles. DLS showed that after solubilization the size of the micelles became bigger. In vitro tests showed that silymarin was slowly released from micellar solution and the release lasted up to 40 h by means of the dialysis method.
Fracture Behavior of Covalently Re‐Modified MWNT/Epoxy Nanocomposites
Authors: Kaffashi Babak , Kaveh Amir
Published: December 2010

Summary: In this work, a surface re‐modified multi‐walled carbon nanotube (MWNT) was prepared by the chemical attachment of oligomeric unsaturated polyester on the MWNT surface. The re‐modified MWNT was incorporated in two concentrations of 0.35 and 0.70 Wt.% into epoxy resin in order to investigate its effect on morphology and mechanical behavior of the MWNT/epoxy nanocomposite. The transmission electron microscopy showed that the re‐modification of MWNT surface improves its dispersion state in the epoxy matrix. The tensile measurements for the nanocomposite having different amounts of surface re‐modified/not‐modified MWNT showed that the fracture mechanism changed from brittle to tough beyond a certain amount of surface re‐modified MWNT. The scanning electron microscopy findings on the fracture surface morphology of the resulted nanocomposite substantiated the observed phenomena.
Chronic dietary intake of quercetin alleviates hepatic fat accumulation associated with consumption of a Western‐style diet in C57/BL6J mice
Authors: Kobori Masuko , Masumoto Saeko , Akimoto Yukari , Oike Hideaki
Published: December 2010

Scope: To determine the effect of consumption of a quercetin‐rich diet on obesity and dysregulated hepatic gene expression.

Methods and results: C56BL/6J mice were fed for 20 wk on AIN93G (control) or a Western diet high in fat, cholesterol and sucrose, both with or without 0.05% quercetin. Triglyceride levels in plasma, thiobarbituric acid‐reactive substances (oxidative stress marker) and glutathione levels and peroxisome proliferator‐activated receptor α expression in livers of mice fed with the Western diet were all improved after 8 wk feeding with quercetin. After 20 wk, further reductions of visceral and liver fat accumulation and improved hyperglycemia, hyperinsulinemia, dyslipidemia and plasma adiponectin and TNFα levels in these mice fed with quercetin were observed. The expression of hepatic genes related to steatosis, such as peroxisome proliferator‐activated receptor γ and sterol regulatory element‐binding protein‐1c was also normalized by quercetin. In mice fed with the control diet, quercetin did not affect body weight but reduces the plasma TNFα and hepatic thiobarbituric acid‐reactive substance levels.

Conclusion: In mice fed with a Western diet, chronic dietary intake of quercetin reduces liver fat accumulation and improves systemic parameters related to metabolic syndrome, probably mainly through decreasing oxidative stress and reducing PPARα expression, and the subsequent reduced expression in the liver of genes related to steatosis.
A new material classification of lossy metamaterials
Authors: Lee Dong Hyun , Park Wee Sang
Published: December 2010

The propagation constant is extended and derived for lossy metamaterials in which ε < 0 and μ > 0 (ENG), ε > 0 and μ < 0 (MNG), and ε < 0 and μ < 0 (DNG).Regardless of the magnitudes of ε and μ, DPS materials are a RH medium and DNG materials are a LH medium. However, SNG materials become a RH medium when the sign of (ε × μ + ε × μ) is positive and a LH medium when the sign is negative. A new diagram is proposed to classify any lossy metamaterial into either RH or LH medium. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:445–447, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25687
A novel highly sensitive optical fiber microphone based on single mode–multimode–single mode structure
Authors: Sun An , Semenova Yuliya , Farrell Gerald
Published: December 2010

In this article, a novel multimode interference based optical fiber microphone by employing single mode‐multimode‐single mode (SMS) structure is presented. The acoustic vibration is measured by detecting the transmission loss of the SMS structure that attached to a thick aluminum membrane. Experiments are carried on to test the performance of SMS structured fiber microphone, and the experimental results show that the SMS fiber sensor can effectively detect the acoustic signal within the audio range of 20 kHz. It also exhibits a high sensitivity and human voice can also be picked up effectively within the distance of 2 m. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:442–445, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25688
Internal dual‐antenna in the folder‐type mobile phone for DVB‐H and 3G applications
Authors: Zuo Shaoli , Yin Yingzeng , Zhang Zhiya , Ren Xueshi
Published: December 2010

A dual‐antenna system that consists of a planar meander monopole antenna and a planar inverted‐F antenna (PIFA) in the folder‐type mobile phone is proposed. By using the planar monopole type radiating element constructed with meander strips, the monopole antenna provides a degree of miniaturization while retaining a wide impedance bandwidth of 740 MHz (440–1180 MHz) and 220 MHz (1710–1930 MHz) that covers DVB‐H/GSM/DCS within 3:1 VSWR; while by exciting dual‐resonant modes of 1/8 λ at 900 MHz and 1/4 λ at 1800 MHz, the PIFA with coupling feed shows dual impedance bandwidths of 142 MHz (858–1000 MHz) and 410 MHz (1790–2200 MHz) that covers GSM/PCS/3G(UMTS) within 3:1 VSWR. The approximately omnidirectional pattern, good gain, over the operating bands have also been obtained. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:306–310, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25695
Low‐profile Fabry–Pérot cavity antenna with a double‐layered partially reflecting surface structure
Authors: Ju J. , Kim D. , Lee W. , Choi J.
Published: December 2010

A low‐profile Fabry–Pérot cavity antenna covered with a double‐layered partially reflecting surface is proposed to enhance the gain and reduce the height of the antenna.A ray theory is applied to predict the resonance frequency and cavity height of the proposed antenna. The proposed antenna is useful for designing a cavity antenna with a low profile and high gain. The maximum gain of the antenna is 13.88 dB, and its total height is smaller than λ/8 at an operating frequency of 2.46 GHz. The good agreement between the measured and predicted results ensures the validity of our design approaches. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:271–273, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25698
Forward–backward time‐stepping method combined with genetic algorithm applied to breast cancer detection
Authors: Moriyama Toshifumi , Meng Zhiqi , Takenaka Takashi
Published: December 2010

A hybrid method of forward–backward time‐stepping algorithm and genetic algorithm is applied to microwave imaging for breast cancer detection.A two‐dimensional numerical breast phantom with high contrast between fat and fibroglandular tissues and low contrast between fibroglandular and tumor tissues is used to assess the efficacy of the proposed method. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:438–442, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25699
A six‐pole ultra‐narrowband high‐temperature super conducting filter at S‐band
Authors: Zhang Ying , Guo Xubo , Chen Wei , Lu Xinxiang , Zhang Xiaoping , Wei Bin , Cao Bisong
Published: December 2010

This article presents a six‐pole high‐temperature superconducting (HTS) filter with a fractional bandwidth (FBW) of 0.09% at 3.3 GHz. Twin‐spiral resonators with a high quality factor (Qu) of 69,000 are used in the design procedure. The measured results of the filter exhibit a low insertion loss of 0.62 dB and are in good agreement with the simulated ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:435–438, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25700
A novel compact bandstop filter using defected microstrip structure
Authors: La Dongsheng , Lu Yinghua , Sun Siyang , Liu Ning , Zhang Jingling
Published: December 2010

In this article, a new defected microstrip structure (DMS) which is used to design filter is introduced.Its resonant characteristics can be adjusted by changing the dimension of the structure unit. A novel bandstop filter is designed based on this structure. There are two transmission zeros located at about 4.08 GHz and 6.2 GHz, respectively. The measured results show a good agreement with the simulation. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:433–435, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25708
A uneven Doherty power amplifier using anticoupled power divider and composite right/left‐handed transmission lines
Authors: Zhao Shiwei , Tang Zongxi , Wu Yiwei , Bao Lifen
Published: December 2010

A uneven Doherty power amplifier using anticoupled power divider and composite right/left‐handed transmission lines (CRLH‐TL) is proposed for efficiency and linearity improvement.Uneven power divider is achieved by anticoupled line divider and CRLH‐TL, the structure is used to deliver more input power to the peaking amplifier than the main amplifier. The CRLH‐TL with lead 90° phase shifter at the input of maim amplifier is designed to flexible variation of power division ratio and phase, besides, anticoupled power divider to suppress the second harmonic of front class input. The drain efficiency of 45.2 and 39.3% has been measured at the saturated output power of 43 dBm and 6‐dB back off, respectively. Furthermore, the third‐order intermodulation distortion performance and ACLR is improved as much as 5–6 dB when compared with conventional uneven Doherty amplifier. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:322–324, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25715
Compact tunable lumped‐element Wilkinson power divider with high isolation
Authors: Mung Steve W. Y. , Chan Wing Shing
Published: December 2010

In this letter, a compact tunable lumped‐element Wilkinson power divider is proposed.It is realized by the electronically tunable microwave impedance transformers controllable by varactor diodes. The proposed divider possesses a tunable frequency range over a bandwidth of 53% different from the conventional Wilkinson power divider. Experimental results show that it can operate over the tunable frequency range from 1.1 to 1.9 GHz with more than 50 dB isolation between the isolated ports. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:288–290, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25717
Field prediction in urban environment using radar approach
Authors: Ouattara Yélakan B. , Richalot Elodie , Picon Odile , Wiart Joe
Published: December 2010

To accelerate radio channel predictions in urban environment, the use of the radar cross section is proposed as a compact representation of far‐field buildings scattering. Simple analytical formulas are obtained, and multiple scattering between buildings is taken into account by combining them with the ray‐tracing approach. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:257–261, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25726
Millimetre‐wave radio‐over‐fibre data transmission over multimode fibre
Authors: Khawaja Bilal A. , Cryan Martin J.
Published: December 2010

This article presents non‐return‐to‐zero (NRZ), binary phase‐shift keying (BPSK) data transmission over 100 m (50‐μm core) and 200 m (62.5‐μm core) millimetre‐wave multimode radio‐over‐fibre (RoF) links.The system consists of a 1.55‐μm tunable laser source, a wide bandwidth 40‐Gb/s Mach‐Zehnder Modulator (MZM), and a high‐speed photodiode for detection. Successful data transmission of 900 Mb/s over 100 m and 500 Mb/s over 200‐m multimode RoF links is achieved. A millimetre‐wave carrier frequency of 38.8 GHz is used for the data transmission over multimode fibres which is believed to the highest reported so far. After the RoF links eye‐diagrams are recovered with good Q‐factor performance recorded. These measurements show that multimode fibre links have the potential for use in next generation in‐building/campus wide pico‐cellular and low cost distributed antenna systems. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:254–256, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25727
Research on the electromagnetic scattering of 3D target coated with anisotropic medium using impedance boundary condition
Authors: Yu Ding‐Feng , He Si‐Yuan , Chen Hai‐Tao , Zhu Guo‐Qiang
Published: December 2010

Based on impedance boundary condition, a method of moments solution for the electromagnetic scattering of three‐dimensional target coated with anisotropic medium is presented.According to the surface equivalence principle, the scatters can be replaced by equivalent electric and magnetic current source expanded by Rao‐Wilton‐Glisson vector‐basis functions. Using electric‐field integral equation, Galerkin moment method can deal with the electromagnetic issues of arbitrary structural targets (surface open or closed) simply and effectively. Electromagnetic parameters of medium are characterized by the surface impedance matrix, to simulate the anisotropic materials. Several numerical examples of typical target coated with anisotropic media are presented, and the results are compared with the physical optics solution, reasonable analysis is given as well. By setting the surface impedance matrix, the issue can be degraded to isotropic medium coating case or perfectly electric conductor case, and the proposed algorithm is still efficient and accurate. Simulation analysis to the electromagnetic scattering of plasma coating space satellite is presented, which provides theoretical support for the radar stealth and shows the proposed algorithm's value for engineering applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:458–462, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25728
A low‐voltage 5.4 GHZ monolithic cascode LNA using 0.18 um CMOS technology
Authors: Liu Baohong , Mao Junfa
Published: December 2010

This article presents a low‐voltage monolithic cascode LNA using 0.18‐um CMOS technology. Different from the stacked threshold voltage supply topology of conventional cascode LNA, this cascode LNA is designed as two cascaded stages for low‐voltage application. For the purpose of lowering the whole power dissipation while RF performances are not influenced, the current occupation is reduced by decreasing the channel width of the second NMOS. The whole circuit is implemented through TSMC 0.18‐um CMOS technology. Measurement results show that it can get 10.7‐dB gain and 2.6 dB NF at frequency of 5.4 GHz. The IIP3 is about −2.3 dBm. The supply voltage is only 0.7 V, and the whole power dissipation is 6.3 mW. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:386–389, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25733