bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Characterization and Remarkable Axial Ligand Effect on the Nucleophilic Reactivity of a Nonheme Manganese(III)–Peroxo Complex
Authors: Annaraj Jamespandi , Cho Jaeheung , Lee Yong‐Min , Kim Sung Yeon , Latifi Reza , de Visser Sam P. , Nam Wonwoo
Published: May 2009

Seitlich angedockt: In dem Mangan(III)‐Komplex 1 mit einem 13‐gliedrigen makrocyclischen Liganden ist ein Peroxoligand durch Side‐on‐η2‐Koordination gebunden. Die Reaktivität von 1 wird durch Einführung anionischer Liganden in trans‐Stellung zur Peroxogruppe beeinflusst. Elektronische und strukturelle Änderungen bei der Bindung des trans‐Liganden erklären die höhere Nucleophilie der entstehenden Komplexe 1‐X.

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Asymmetric Syntheses of l,l‐ and l,d‐Di‐myo‐inositol‐1,1′‐phosphate and their Behavior as Stabilizers of Enzyme Activity at Extreme Temperatures
Authors: Longo Christina M. , Wei Yang , Roberts Mary F. , Miller Scott J.
Published: May 2009

Hitzeschutz: Die Totalsynthese von l,l‐DIP und l,d‐DIP (siehe Strukturen) beinhaltet als Schlüsselschritt den komplexen Fall einer doppelten asymmetrischen Induktion. Die thermoprotektive Wirkung beider Isomere auf Enzyme wurde untersucht, und beide zeigen biologische Aktivität.

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Efficient and Economical Access to Substituted Benzothiazoles: Copper‐Catalyzed Coupling of 2‐Haloanilides with Metal Sulfides and Subsequent Condensation
Authors: Ma Dawei , Xie Siwei , Xue Peng , Zhang Xiaojing , Dong Jinhua , Jiang Yongwen
Published: May 2009

Mit einfachsten Mitteln: Die erste metallkatalysierte direkte Kupplung zwischen Metallsulfiden und Arylhalogeniden mit anschließender intramolekularer Kondensation ergab substituierte Benzothiazole (siehe Schema). Zahlreiche funktionelle Gruppen waren mit den Reaktionsbedingungen kompatibel.

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Elektronentransfer entlang Peptiden mit Cystein und Methionin als Relais‐Aminosäuren
Authors: Wang Min , Gao Jian , Müller Pavel , Giese Bernd
Published: May 2009

Sprung ins Wasser: Bei mehrstufigen Elektronentransferreaktionen (ETs) durch Peptide können auch aliphatische Aminosäuren als Relaisstationen fungieren. Mit Cystein erfolgt ein protonengekoppelter Elektronentransfer (PCET), wobei Wasser als Mediator für den Protonentransfer wirkt (siehe Bild).

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Three Redox States of Nitrosyl: NO+, NO., and NO−/HNO Interconvert Reversibly on the Same Pentacyanoferrate(II) Platform
Authors: Montenegro Andrea C. , Amorebieta Valentín T. , Slep Leonardo D. , Martín Diego F. , Roncaroli Federico , Murgida Daniel H. , Bari Sara E. , Olabe José A.
Published: May 2009

Not so elusive: [FeII(CN)5(HNO)]3− has been characterized spectroscopically after the two‐electron reduction of nitroprusside (see scheme). The complex is stable at pH 6, slowly decomposing to [Fe(CN)6]4− and N2O. It is deprotonated at increasing pH value with oxidation of bound NO− to [FeII(CN)5(NO)]3−. [FeII(CN)5(HNO)]3− is the first non‐heme iron–nitroxyl complex prepared in aqueous solution that is reversibly redox‐active under biologically relevant conditions.

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Bioinspired Colorimetric Detection of Calcium(II) Ions in Serum Using Calsequestrin‐Functionalized Gold Nanoparticles
Authors: Kim Sunghyun , Park Jeong Won , Kim Dongkyu , Kim Daejin , Lee In‐Hyun , Jon Sangyong
Published: May 2009

Seeing is sensing: Calsequestrin (CSQ) functionalized gold nanoparticles undergo calcium‐dependent CSQ polymerization, which results in a clear color change (see picture) together with precipitation. The sensing system is specific for Ca2+ ions and the differences between normal and disease‐associated abnormal (hypercalcemia) Ca2+ ion levels in serum can be distinguished with the naked eye.

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Disterolphospholipids: Nonexchangeable Lipids and Their Application to Liposomal Drug Delivery
Authors: Huang Zhaohua , Jaafari Mahmoud Reza , Szoka Francis C.
Published: May 2009

Extreme makeover of cholesterol: Cholesterol exchange is a major reason for the instability of liposomes in blood. The formation of a covalent hybrid between cholesterol and glycerophosphocholine preserves the bilayer‐stabilizing effect of free cholesterol but prevents its transfer from the bilayer. Thus, disterolphospholipids (e.g.1) are valuable new components for liposome formulation.

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Electron Transfer in Peptides with Cysteine and Methionine as Relay Amino Acids
Authors: Wang Min , Gao Jian , Müller Pavel , Giese Bernd
Published: May 2009

Caught on the hop: In multistep electron transfer (ET) reactions through peptides, aliphatic amino acids can also act as relay stations. With cysteine, the reaction occurs as a proton‐coupled electron transfer (PCET) with water used as a mediator for the proton transfer (see picture).

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Symmetry‐Based Design for the Chemoenzymatic Synthesis of Oseltamivir (Tamiflu) from Ethyl Benzoate
Authors: Sullivan Bradford , Carrera Ignacio , Drouin Melissa , Hudlicky Tomas
Published: May 2009

A short chemoenzymatic formal synthesis of oseltamivir from ethyl benzoate has been achieved. The key steps involve a toluene dioxygenase‐mediated dihydroxylation, hetero‐Diels–Alder cycloaddition, and generation of C4 acetamido functionality. The formal synthesis of oseltamivir is achieved in ten steps and incorporates a unique translocation of the olefin with concomitant elimination of the C2 hydroxy group (see scheme).

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Degradation behavior of nanoreinforced epoxy systems under pulse laser
Authors: Calhoun M. , Kumar A. , Aglan H.
Published: May 2009

Nanocomposites using EPON 824 as their matrix were exposed to pulse laser at 532 nm for various time intervals. The developed nanomaterials used for this study were manufactured using EPON 824 with multiwalled carbon nanotubes (MWCNTs) at a loading rate of 0.15% by weight and nanoclays at a loading rate of 2% by weight as reinforcements. The effect of laser irradiation on polymer composites has been investigated. The degradation mechanism for the epoxy was of a laser induced burning nature. Of all specimens tested, the ultimate strength of the MWCNT‐reinforced specimens decreased the most as a function of radiation time; the nanoclay‐reinforced epoxy retained the most strength after 2 min of laser radiation. In addition, the threshold fluence for decomposition indicated that less energy was required to initiate decomposition in the MWCNT‐reinforced epoxy than in the nanoclay‐reinforced epoxy. This can be attributed to the high thermal conductivity of the carbon nanotubes. Measurement of surface damage in the material was observed via electron microscopy. Fourier transform infrared spectroscopy was used to investigate changes to the molecular structure as a function of exposure time. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and thermal and thermo‐oxidative stability of vinylidene chloride‐co‐vinyl chloride copolymer/synthetic hectorite nanocomposites
Authors: Hsieh Tar‐Hwa , Ho Ko‐Shan , Bi Hsiaotao T. , Hung Jan‐Kuan , Han Yu‐Kai , Yang Shin‐Shiao , Chang Yu‐Chen
Published: May 2009

Poly(vinylidene chloride‐co‐vinylchloride)/organically modified hectorite (VDC‐VC/SPN) nanocomposites were prepared by melt blending VDC‐VC copolymer with SPN in the presence of dioctyl phthalate, which acted as a plasticizer. As a result, the exfoliated structure was found in the VDC‐VC/SPN nanocomposites. In nitrogen atmosphere, VDC‐VC/SPN nanocomposites exhibited a single‐step thermal degradation. The thermal stability of VDC‐VC/SPN nanocomposites is significantly influenced by the SPN, which was modified with long alkyl ternary ammonium salt. In air atmosphere, VDC‐VC/SPN nanocomposites revealed a two‐step thermo‐oxidative degradation behavior. At the first degradation stage, the weight loss pattern is similar to that of VDC‐VC composites in nitrogen, in which the thermo‐oxidative stability of VDC‐VC/SPN nanocomposites is affected by the ternary ammonium salt and oxygen rather than its morphology. At the second degradation stage, both the enhanced thermo‐oxidative stability and the flame‐retardation ability of VDC‐VC composites are strongly and closely related to the morphology of nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci ,2009
Dynamically vulcanized blends of polypropylene and ethylene octene copolymer: Influence of various coagents on mechanical and morphological characteristics
Authors: Babu R. Rajesh , Singha Nikhil K. , Naskar Kinsuk
Published: May 2009

Dynamically cured blends of polypropylene (PP) and ethylene octene copolymer (EOC) with coagent‐assisted peroxide curative system were prepared by melt‐mixing method. It was well established that PP exhibits β‐chain scission in the presence of peroxide. Principally, incorporation of a coagent increases the crosslinking efficiency in the EOC phase and decreases the extent of degradation in the PP phase. The present study mainly focused on the influence of three structurally different coagents, namely, triallyl cyanurate (TAC), trimethylol propane triacrylate (TMPTA), and N,N′‐m‐phenylene dimaleimide (MPDM), on the mechanical properties of the PP/EOC thermoplastic vulcanizates (TPVs). The reactivity and efficiency of different coagents were characterized by cure study on EOC gum vulcanizate. TAC showed the highest torque values followed by MPDM and TMPTA. Significant improvements in the physical properties of the TPVs were inferred with the addition of coagents. Among the three coagents used, MPDM showed the best balance of mechanical properties in these TPVs. The results indicated that torque values obtained during mixing and the final mechanical properties can be correlated. Different aspects were explained for the selection of a coagent that forms a product with desired properties. The phase morphologies of the TPVs prepared were studied by scanning electron microscopy. Tensile fracture patterns were also analyzed to study the failure mechanism of the samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Reduction of free radicals and endotoxin by conjugated linoleic acid loaded in an in situ‐synthesized poly(N‐isopropyl acrylamide) thin layer
Authors: Huang Li‐Heng , Wu Jiunn‐Tzong , Su Te‐Li , Yang Ming‐Chien , Kuo Yu‐Lin , Kung Fu‐Chen
Published: May 2009

A thin layer of poly(N‐isopropyl acrylamide) (pNIPAAm) was synthesized in situ on the surface of hydrolyzed polyacrylonitrile (PAN) membrane. This thin layer exhibited both pH response due to the poly(acrylic acid) moiety and temperature response due to the pNIPAAm moiety. The swelling behavior of the membranes was evaluated under various temperatures and pH. The curve of the swelling ratio for the PAN‐NIPAAm showed a lower critical solution temperature. Then, conjugated linoleic acid (CLA) was loaded into the pNIPAAm layer. The effects of CLA on the blood coagulation and oxidative stress were evaluated with the use of human blood. The level of reactive oxygen species (ROS) was measured by the chemiluminescence (CL) method to evaluate the oxidative stress. Furthermore, the removal of bacterial endotoxin (lipopolysaccharide) by CLA‐loaded PAN‐NIPAAm was measured with enzyme‐linked immunosorbent assay. The results show that the LCST swelling curve was at 37°C. PNIPAAm chains form expanded structures under 37°C. At temperatures greater than 37°C, however, the chains form compact structures by dehydration. This makes PNIPAAM membrane due to rapid hydration and dehydration changes of the polymer chain. In addition, the swelling ratio increased by 71% when the pH increased from 5 to 10. The concentration of LPS can be reduced by CLA‐loaded PAN‐NIPAAm 2.1 and 1.2 times of that by unmodified PAN and PAN‐NIPAAm membranes, respectively. In addition, the level of ROS against CLA‐loaded PAN‐NIPAAm was reduced significantly than that against unmodified PAN and PAN‐NIPAAm. Therefore CLA‐loaded PAN‐NIPAAm membrane could offer protection for patients against oxidative stress and could also inhibit lipopolysaccharide for clinical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and properties of poly(WPSF‐co‐butyl acrylate) copolymer emulsion with ultrasonic radiation II. Monomer conversion rate and characterization
Authors: Ai Zhao Quan , Zhang Hai Rong , Liu Qing , Hu Ying
Published: May 2009

A stable emulsion of poly(WPSF‐co‐butyl acrylate) based on butyl acrylate, waste polystyrene foam was synthesized through emulsion polymerization using sodium dodecyl sulfate and octyl phenyl polyoxyethylene ether as surfactant, ammonium persulfate and sodium hydrogen bisulfate as mixed redox initiator, under ultrasound irradiation in the absence of inert gas. The effects of various copolymerization conditions on the monomer conversion were reported. The copolymers were characterized by means of IR, 1HNMR, and gel permeation chromatography. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal and mechanical characterization of maleimide‐functionalized copoly(urethane‐urea)s
Authors: Gaina Constantin , Gaina Viorica , Ciobanu Constantin
Published: May 2009

Maleimide functionalized copoly(urethane‐urea)s were prepared by the reaction of a binary mixture of dibenzyldiisocyanate and 5‐maleimidoisophthalic diisocyanate with a macrodiol (PEGA‐2000), using diethylene glycol and trimethylol‐propane as chain extender and crosslinkers in toluene‐dichloromethane solutions at the ratio NCO/OH = 1.2. Structures of polymers were confirmed by IR spectroscopy and properties were studied by thermal and mechanical analysis (dynamic mechanical analysis (DMA), differential scanning calorimetry, thermogravimetric analysis, stress‐strain) and other physical methods. Maleimide modification increased the storage modulus and Young's modulus of copoly(urethane‐urea)s, slightly increased their glass transition temperature from −10.6°C to −6.3°C. Copoly(urethane‐urea) networks obtained by thermal polymerization of maleimide functions showed significantly increased of the mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The characterization of polyaniline and polypyrrole composites by pyrolysis mass spectrometry
Authors: Hacaloglu Jale , Tezal Feride , Kücükyavuz Zühal
Published: May 2009

In this work, direct insertion probe pyrolysis mass spectrometry technique was applied to investigate the thermal and structural characteristics of electrochemically prepared polyaniline (PANI), polypyrrole (PPy), and their composites/copolymers synthesized either by electrochemical polymerization of pyrrole on PANI‐coated electrode (PANI/PPy) or by coating PANI on PPy (PPy/PANI) in H2SO4 solutions. It has been determined that the polymer first coated on the electrode degraded to a certain extent during the polymerization of the second. The extent of degradation was greater for PPy and increased with the increase in acid concentration. On the other hand, the detection of mixed dimers confirmed copolymer formation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Electromagnetic interference shielding behavior of polyaniline/graphite composites prepared by in situ emulsion pathway
Authors: Saini Parveen , Choudhary Veena , Sood K. N. , Dhawan S. K.
Published: May 2009

Polyaniline–graphite composites were prepared via in situ emulsion pathway, using different weight ratios of aniline to graphite. These composites were characterized for thermal, electrical, and spectral attributes. The thermal stability (∼ 230°C) and electrical conductivity (67.9 S/cm) were improved significantly as compared with polyaniline doped with conventional inorganic dopants such as HCl (140°C and 10 S/cm). Scanning electron micrographs indicated a systematic change in morphology from globular to flaky with increasing amounts of graphite. The relative shifting of UV–visible bands indicates that some interactions exist between doped polyaniline and graphite. Absorption‐dominated total electromagnetic interference shielding effectiveness of the order of −33.6 dB suggests that these materials can be used as futuristic microwave shielding materials. The good electrical conductivity and thermal stability make them ideal candidates for preparing conducting composites by melt blending with conventional thermoplastics such as polyethylene, polypropylene, and polystyrene, etc. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Modification of cellulose acetate with oligomeric polycaprolactone by reactive processing: Efficiency, compatibility, and properties
Authors: Klébert Szilvia , Nagy Lajos , Domján Attila , Pukánszky Béla
Published: May 2009

Oligomeric polycaprolactone (oPCL) was used for the modification of cellulose acetate by reactive processing in an internal mixer at 180°C, 50 rpm, 60 min reaction time, and 45 wt % caprolactone (CL) content. The product of the reaction was characterized by several analytical techniques and its mechanical properties were determined by dynamic mechanical thermal analysis and tensile testing. The synthesized oPCL contained small and large molecular weight components. The small molecular weight fraction plasticized cellulose acetate externally and helped fusion. Although composition and structure did not differ considerably from each other when CL monomer or polycaprolactone oligomer was used for modification, the grafting of a few long chains had considerable effect on some properties of the product. The large molecular weight chains attached to CA increased the viscosity of the melt considerably and resulted in larger deformability. oPCL homopolymer is not miscible with cellulose acetate and migrates to the surface of the polymer. Exuded polycaprolactone oligomers crystallize on the surface but can be removed very easily. More intense conditions may favor the grafting of long chains leading to polymers with advantageous properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Durability enhancement of Nafion® fuel cell membranes via in situ sol‐gel‐derived titanium dioxide reinforcement
Authors: Patil Yatin , Mauritz Kenneth A.
Published: May 2009

To improve durability of Nafion® membranes, samples were modified via an in situ sol‐gel polymerization of titanium isopropoxide to generate titania quasi‐networks in the polar domains. The incorporated titania reduced water uptake but equivalent weight was essentially unchanged. Fuel cell performance of the modified membrane was inferior to that of the unfilled membrane although these were considered as model studies with focus on mechanical durability. Mechanical analysis of contractile stress buildup during drying from a swollen state in samples clamped at constant length demonstrated considerable reinforcement of Nafion® by the titania structures. Tensile studies showed that at 80°C and 100% relative humidity the dimensional change of the composite membrane is one half and the initial modulus is three times higher than that of the unmodified membrane. During an open circuit voltage decay test the voltage decay rate for the modified membrane is 3.5 times lower than that of control Nafion®. Fluoride emission for the composite is at least an order of magnitude lower than that of the control Nafion® membrane indicating reduced chemical degradation. These model studies indicate that this in situ inorganic modification offers a way to enhance fuel cell membrane durability by reducing both physical and chemical degradation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The role of auxiliary monomers and emulsifiers on wet scrub resistance of various latex paints at different pigment volume concentrations
Authors: Khorassani M. , Afshar‐Taromi F. , Mohseni M. , Pourmahdian S.
Published: May 2009

This work is an attempt to study the effect of different latex types containing various auxiliary monomers and emulsifiers on their pigmentation and their corresponding behavior on scrub resistance. The auxiliary monomers investigated were acrylic acid (AA), methacrylic acid (MAA), and itaconic acid and the emulsifiers contained sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS). It was shown that a semibatch polymerization technique which led to smaller particles and sharper size distributions is preferable. The best wet scrub results were obtained by using MAA and SLS. It was also shown that the proper selection of an auxiliary monomer generally depended on the range of incorporated pigment volume concentration (PVC). At high PVCs, AA gave better performances compared with MMA. The reverse effect was shown to occur at low PVCs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Introduction of a new vegetable fiber for textile application
Authors: Mortazavi Sayed Majid , Moghadam Meghdad Kamali
Published: May 2009

Finding textile applications for a new or underused fiber is always very attractive, especially when the fiber is natural and indigenous. Leafiran fiber is derived form the leaves of a plant called Typha australis, which belongs to the family Typhaceae. The fiber was obtained by chemical retting. Some properties of this fiber, such as its tensile strength, chemical composition, thermal properties, moisture absorption, and IR spectra, were determined. Leafiran is a lignocellulosic fiber having a cellulose content of 54%, a moisture regain of 8–10%, and a tenacity of 29 cN/tex. The results show that Leafiran could be an ideal replacement for some widely used natural textile fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic study of free volume properties in polyethylene/styrene butadiene rubber blends by positron annihilation lifetime method
Authors: Mostafa N. , Ali E. Hassan , Mohsen M.
Published: May 2009

Positronium (Ps) formation in low and high‐density polyethylene (LDPE and HDPE) and styrene butadiene rubber (SBR), as well as in their blends (LDPE/SBR: 50/50 and HDPE/SBR: 50/50) has been investigated by positron annihilation lifetime (PAL) measurements as a function of low temperature (100–300 K). The glass transition temperature (Tg) for the initial polymers and their blends are determined by ortho‐positronium (o‐Ps) lifetime, τ3 versus temperature as well as by differential scanning calorimetry (DSC) measurements. The temperature dependence of nanoscale free volume size shows similar trend for all the investigated samples indicating an abrupt change at Tg, which is found to be higher for SBR sample characterized by its high chain mobility. In addition, The Tg values deduced from PAL measurements are compared with the corresponding data deduced from DSC. The variation of o‐Ps formation probability I3 versus temperature for polyethylene and their blends were interpreted in the frame work of spur reaction model of Ps formation. On the other hand, the lifetime coefficient below and above Tg is found to be one order of magnitude larger than the linear expansion coefficient. This constitutes evidence that Ps is only probing free volumes. The results obtained from change in free volume–hole distribution with temperature reflect both thermal expansion and increase in free volume–hole size with the rise in temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Terpolymer resin–III: Synthesis and characterization of 8‐hydroxyquinoline–dithiooxamide–formaldehyde terpolymer resins
Authors: Katkamwar S. S. , Zade A. B. , Rahangdale S. S. , Gurnule W. B.
Published: May 2009

Terpolymer resins (8‐HQDF) were synthesized by the condensation of 8‐hydroxyquinoline (8‐HQ) and dithiooxamide (D) with formaldehyde (F) in the presence of acid catalyst and using varied molar ratios of reacting monomers. Terpolymer resins compositions have been determined on the basis of their elemental analysis and the number average molecular weights of these resins were determined by conductometric titration in non‐aqueous medium. Viscometric measurements in dimethyl formamide (DMF) have been carried out with a view to ascertain the characteristic functions and constants. The UV‐visible, FTIR, and proton nuclear magnetic resonance (H+ NMR) spectra were studied to elucidate the structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Humidity‐dependent bending recovery and relaxation of human hair
Authors: Wortmann Franz J. , Stapels Michael , Chandra Lalitesh
Published: May 2009

The time‐dependent bending recovery of human hair fibers was investigated for a variety of relative humidities and aging times. The data were analyzed on the basis of a viscoelastic filament/matrix model and the Denby‐equation, containing the parameter K as the ratio of the elastic bending rigidities of the matrix and the filaments and the Kohlrausch‐Williams‐Watts (KWW) function as relaxation function. The first stage of the analysis ascertained that the recovery curves shift with aging time on the time scale with the expected aging rate of μ ≈ 1. The second stage showed that the shape factor of the KWW function exhibits a mean value across the aging and humidity range of m = 0.28, which is close to the “universal” value of 1/3. On this basis, it was found that virtually no change occurs for the modulus ratio for low water contents up to about 10%, being constant at K0= 6 .1, while linearly decreasing beyond this threshold. The reduced, characteristic relaxation time drops on the log‐time scale from logτr(0) = 0.47 for the dry fiber linearly with water content, covering about two thirds of a decade for 0–20% water content. With the pronounced humidity dependence of the parameters, hair shows what is termed hydro‐rheologically complex (HRC) in analogy to thermo‐rheologically complex behavior. Using the HRC approach, the dynamical mechanical performance of hair (1 Hz) was calculated for a range of water contents and aging times and found to be in good general agreement with experimental data. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Anatomy education faces challenges in Pakistan
Authors: Memon Ismail K.
Published: May 2009

Anatomy education in Pakistan is facing many of the same challenges as in other parts of the world. Roughly, a decade ago, all medical and dental colleges in Pakistan emphasized anatomy as a core basic discipline within a traditional medical science curriculum. Now institutions are adopting problem based learning (PBL) teaching philosophies, and since medical colleges in Pakistan first introduced PBL curricula that expose the basic sciences primarily in clinical contexts, the methods and extent of anatomy teaching have been topics of much debate. Many claim that PBL curricula dilute basic science education, especially anatomy. At the same time, classically trained faculty members with PhD in anatomy have become nearly extinct in Pakistan, with only four working in country. A third challenge currently facing anatomy education in Pakistan, as in many parts of the world, is an unavailability of cadavers for dissection. As more institutions adopt PBL curricula, as PhD anatomists are harder to find, and as cadavers for dissection become scarce, Pakistan and other countries around the world will have to seriously consider how they will sustain adequate anatomy education. Anat Sci Educ 2:193–194, 2009. © 2009 American Association of Anatomists.
CT demonstration of caput medusae
Authors: Weber Edward C. , Vilensky Joel A.
Published: May 2009

Maximum intensity and volume rendered CT displays of caput medusae are provided to demonstrate both the anatomy and physiology of this portosystemic shunt associated with portal hypertension. Anat Sci Educ 2:184–185, 2009. © 2009 American Association of Anatomists.
Perturbation of the tris(2,2′‐bipyridine) ruthenium(II)‐catalyzed Belousov–Zhabotinsky oscillating chemiluminescence reaction by l‐cysteine and its application
Authors: Liu Huimin , Han Heyou
Published: May 2009

Perturbation of the tris(2,2′‐bipyridine)ruthenium(II) [Ru(bpy)32+]‐catalyzed Belousov–Zhabotinsky (BZ) oscillating chemiluminescence (CL) reaction induced by l‐cysteine was observed in the closed system. It was found that the CL intensity was decreased in the presence of l‐cysteine. Meanwhile, oscillation period and oscillating induction period were prolonged. The sufficient reproducible induction period was used as parameter for the analytical application of oscillating CL reaction. Under the optimum conditions, the changes in the oscillating CL induction period were linearly proportional to the concentration of l‐cysteine in the range from 8.0 × 10−7 to 5.0 × 10−5 mol L−1 (r = 0.997) with a detection limit of 4.3 × 10−7 mol L−1. The possible mechanism of l‐cysteine perturbation on the oscillating CL reaction was also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Optical ascorbic acid sensor based on the fluorescence quenching of silver nanoparticles
Authors: Park Hyun Woo , Alam Seikh Mafiz , Lee Sang Hak , Karim Mohammad Mainul , Wabaidur Saikh Mohammad , Kang Meea , Choi Jong Ha
Published: May 2009

A sensitive and selective fluorimetric sensor for the assay of ascorbic acid (AA) using silver nanoparticles as emission reagent was investigated. In this study, silver nanoparticles were prepared based on aqueous–gaseous phase reaction of silver nitrate solution and ammonia gas. The nanoparticles were water‐soluble, stable and had a narrow emission band. They were used as a fluorescence probe for the assay of ascorbic acid on its quenching effect on the emission of silver nanoparticles. The principal reason for quenching is likely to be a complexation between ascorbic acid and silver nanoparticles. The quenching mechanism was established by Stern–Volmer law. Under the optimum conditions, the quenched fluorescence intensity was linear with the concentration of ascorbic acid in the range of 4.1 × 10−6 to 1.0 ×10−4 m (r = 0.9985) with a detection limit of 1.0 × 10−7 m. The RSD for repeatability of the sensor for the assay of ascorbic acid concentration of 3.0 × 10−5 and 4.0 × 10−6 m was found to be 1.5 and 1.3%, respectively. The proposed method was applied to the determination of ascorbic acid in vegetables and vitamin C tablets. Copyright © 2009 John Wiley & Sons, Ltd.
Development of ultra‐high sensitivity bioluminescent enzyme immunoassay for hepatitis B virus surface antigen using firefly luciferase
Authors: Minekawa Takayuki , Ohkuma Hiroshi , Abe Katsushi , Maekawa Hiroaki , Arakawa Hidetoshi
Published: May 2009

Hepatitis B virus (HBV) infection continues to be a global public health concern. Efficient diagnosis of HBV surface antigen (HBsAg) is useful for identification of infection, treatment and prevention of transfusion‐transmitted viral infections. Seronegative window reduction afforded by a highly sensitive measurement methodology is necessary as a small quantity of virus with infection risk exists for the period characterized by undetectable HBsAg following HBV infection. In this study, a bioluminescent enzyme immunoassay (BLEIA) for HBsAg was developed employing firefly luciferase as a labeling enzyme and a two‐step sandwich immunoassay method. The cut‐off value (10 mIU/mL) was 50‐fold more sensitive relative to conventional chemiluminescent enzyme immunoassay based on luminol luminescence involving peroxidase as the labeling enzyme and the identical antibodies. Preliminary clinical data for this BLEIA revealed that the HBV seroconversion panel derived sequentially from HBV‐infected human blood was detected 11 days following window closure from the first bleed, whereas detection occurred 14–25 days following window closure with the three conventional commercial kits. Copyright © 2009 John Wiley & Sons, Ltd.
Lactone Size Dependent Reactivity in Candida Antarctica Lipase B: A Molecular Dynamics and Docking Study
Authors: Veld Martijn A. J. , Fransson Linda , Palmans Anja R. A. , Meijer E. W. , Hult Karl
Published: May 2009

Size matters: Lactones have extensively been studied as monomers in enzymatic polymerization reactions. Large lactones showed an unexpectedly high reactivity in these reactions. A combination of docking and molecular dynamics studies have been used to explain this high reactivity in terms of productive binding due to the transoid nature of the ester bond in these substrates.

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Buddy balloon to deliver a percutaneous aortic valve device: A percutaneous shoehorn?
Authors: Sheiban Imad , Infantino Vincenzo , Bollati Mario
Published: May 2009

Percutaneous aortic valve replacement is performed with increasing frequency in patients with severe aortic stenosis at prohibitive surgical risk. Currently available devices are however in their early development stage, and are thus quite bulky with a large profile, with ensuing difficulties in delivery of the device through a stenotic aortic valve. We report hereby a case in which we employed a buddy wire and balloon technique as a “shoehorn” to enable accurate delivery of a balloon‐expandable aortic valve prosthesis from the transfemoral route. © 2009 Wiley‐Liss, Inc.
“Armored” aspiration catheter technique to enhance aspiration catheter delivery in challenging thrombus‐containing lesions
Authors: Brilakis Emmanouil S. , Lichtenwalter Christopher , Banerjee Subhash
Published: May 2009

Use of aspiration catheters can improve the outcomes of percutaneous coronary interventions in thrombus‐containing lesions, yet delivery of such catheters may be difficult, especially in tortuous and calcified vessels and when guide catheter support is poor. We report two cases demonstrating successful application of a novel “armored” aspiration catheter technique, in which a 0.035 inch guidewire is inserted via the aspiration lumen to render the aspiration catheter stiffer and facilitate delivery to the target vessel thrombotic segment. © 2009 Wiley‐Liss, Inc.
Retrograde recanalization of chronic total coronary artery occlusion using a novel “reverse wire trapping” technique
Authors: Ge Junbo , Zhang Feng
Published: May 2009

Percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) remains a technical challenge for the interventional cardiologists. Recently, modified techniques based on the retrograde approach have demonstrated that this approach could increase the success rate for PCI of CTO. In the current report, we describe a novel “reverse wire trapping” technique that can help create an antegrade wire route to open CTO after the wire has passed through the CTO retrogradely, even though the retrograde balloon dilatation or antegrade wiring was unapproachable. © 2009 Wiley‐Liss, Inc.
TEVAR for non‐aneurysmal thoracic aortic pathology
Authors: D'Souza Sean , Duncan Audra , Aguila Fernando , Oderich Gustavo , Ricotta Joseph , Kalra Manju , Gloviczki Peter , Bower Thomas , Sundt Thoralf
Published: May 2009

Objective: Management of penetrating atherosclerotic ulcers (PAU), intramural hematomas (IMH), and acute aortic dissections (AD) of the thoracic aorta remain controversial in the endovascular era. Methods: Between 2001 and 2007, patients with PAU (13 patients), and/or IMH (7 patients) were treated with thoracic endografts (TEVAR) in the endovascular suite under general anesthesia. Indications for intervention were intractable chest pain, expanding hematoma or contained rupture, or distal malperfusion. End‐points were early morbidity and mortality, incidence of endoleak, device‐related complications, and secondary interventions. Results: Of the 20 patients with a median age of 67 (25–83), 13 (65%) were men, 2 (10%) had contained aortic rupture, and 10 were symptomatic. One patient had carotid‐subclavian bypass debranching before endograft implantation. Ten patients had cerebrospinal fluid drainage. Mean length of aorta treated was 122.1 mm (range 36–300). All endografts were technically successful. Average blood loss was 50 mL. Thirty‐day mortality was 0%. Symptoms resolved in all patients; there were no neurologic complications. Average length of stay was 5 days. Mean follow‐up was 2.0 years (range 0.1–5.8). All patients remained asymptomatic. Three had early (<180 days) endoleaks: Two type II and 1 type I treated successfully with an additional cuff, which was the only patient requiring reintervention. Two patients had late (>180 days) endoleaks (type 2) observed with no aortic expansion. Two deaths at 5.4 and 5.8 years were due to severe aortic valve stenosis and metastatic lung cancer. Conclusion: TEVAR is a feasible option for repair of non‐aneurysmal thoracic aortic pathology with resolution of symptoms, no mortality, and no neurologic complications. © 2009 Wiley‐Liss, Inc.
Quantitative assessment of the conformational change in the femoropopliteal artery with leg movement
Authors: Klein Andrew J. , James Chen S. , Messenger John C. , Hansgen Adam R. , Plomondon Mary E. , Carroll John D. , Casserly Ivan P.
Published: May 2009

Background:

The unique physical forces exerted on the femoropopliteal (FP) artery during movement have been implicated in the high rates of restenosis and stent fracture in this artery. Conformational changes in the FP artery during movement are important surrogates of these forces. This study sought to quantify the conformational change in the FP artery between the straight‐leg (SL) and crossed‐leg (CL) positions.

Methods:

Using paired angiographic images of overlapping segments of the FP artery in SL and CL positions from patients with peripheral arterial disease, 3‐D models of individual segments were generated and subsequently fused to create a 3‐D model of the entire FP artery in both leg positions. Based on these 3‐D models, the following parameters in the SL and CL positions were quantitatively assessed for the superficial femoral artery (SFA), popliteal artery (PA), and FP artery (i.e., SFA and PA): length, curvature, torsion, twist angle, and development of new flexion angles = 15°.

Results:

In nine male patients with a mean age of 57 ± 10.2 years, angiography was performed in 10 FP arteries, with successful generation of 3‐D models for all vessels. Movement from the SL to the CL position for the SFA, PA, and FP artery was associated with (a) a mean shortening of 18.2 mm (P = 0.002), 32.2 mm (P < 0.001), and 50.3 mm (P < 0.001), respectively; (b) a mean increase in curvature of 0.04 cm−1 (P = 0.012), 0.2 cm−1 (P < 0.001), and 0.11 cm−1 (P < 0.001), respectively; (c) and small absolute changes in mean torsion of 0.034 cm−1 (P = 0.48), 0.006 cm−1 (P < 0.001), and 0.057 cm−1 (P < 0.001), respectively. The same leg movement was associated with a mean twist angle of 45.6° ± 27.9° (range of 17.4°–103.4°) and 61.1° ± 31.9° (range of 20.5°–101.1°) for the SFA and PA, respectively. Compared to the SL position, the CL position induced a single flexion point (FxP) =15° in the SFA in two patients, and a mean of 2.4 FxPs =15° (range 1–5) in the PA.

Conclusions:

Significant changes in length, curvature, and twist occur in the PA and significant but more modest changes in length and twist occur in the SFA during movement from the SL to the CL position. This data has important implications for endovascular therapies that are used to treat disease in the FP artery. © 2009 Wiley‐Liss, Inc.
Fully automatic three‐dimensional quantitative analysis of intracoronary optical coherence tomography
Authors: Sihan Kenji , Botha Charl , Post Frits , de Winter Sebastiaan , Gonzalo Nieves , Regar Evelyn , Serruys Patrick J.W.C. , Hamers Ronald , Bruining Nico
Published: May 2009

Objectives and background: Quantitative analysis of intracoronary optical coherence tomography (OCT) image data (QOCT) is currently performed by a time‐consuming manual contour tracing process in individual OCT images acquired during a pullback procedure (frame‐based method). To get an efficient quantitative analysis process, we developed a fully automatic three‐dimensional (3D) lumen contour detection method and evaluated the results against those derived by expert human observers. Methods: The method was developed using Matlab (The Mathworks, Natick, MA). It incorporates a graphical user interface for contour display and, in the selected cases where this might be necessary, editing. OCT image data of 20 randomly selected patients, acquired with a commercially available system (Lightlab imaging, Westford, MA), were pulled from our OCT database for validation. Results: A total of 4,137 OCT images were analyzed. There was no statistically significant difference in mean lumen areas between the two methods (5.03 ± 2.16 vs. 5.02 ± 2.21 mm2; P = 0.6, human vs. automated). Regression analysis showed a good correlation with an r value of 0.99. The method requires an average 2–5 sec calculation time per OCT image. In 3% of the detected contours an observer correction was necessary. Conclusion: Fully automatic lumen contour detection in OCT images is feasible with only a select few contours showing an artifact (3%) that can be easily corrected. This QOCT method may be a valuable tool for future coronary imaging studies incorporating OCT. © 2009 Wiley‐Liss, Inc.
Balloon angioplasty versus stenting with nitinol stents in intermediate length superficial femoral artery lesions
Authors: Dick Petra , Wallner Hubert , Sabeti Schila , Loewe Christian , Mlekusch Wolfgang , Lammer Johannes , Koppensteiner Renate , Minar Erich , Schillinger Martin
Published: May 2009

Background: Recent randomized trials investigating stent implantation compared with balloon angioplasty for treatment of superficial femoral artery (SFA) disease have given divergent results in short (mean 5 cm) and intermediate (mean 10 cm) lesions. We reinvestigated whether primary nitinol stenting is associated with a morphologic and clinical benefit when compared with percutaneous transluminal angioplasty with optional stenting (PTA) in intermediate‐length lesions. Methods: We randomly assigned 73 patients with severe claudication or chronic limb ischemia and average 8 cm long (range 3–20 cm) SFA stenosis or occlusion to primary stent implantation (n = 34) or PTA (n = 39). Restenosis >50% and clinical outcome were assessed at 3, 6, and 12 months postintervention. Results: Average length of the treated segments was 98 ± 54 mm and 71 ± 43 mm in the stent and PTA groups (P = 0.011), respectively. In the PTA group, secondary stenting was performed in 10 of 39 patients (26%) due to a suboptimal result after balloon dilation. Restenosis rates in the stent and PTA groups were 21.9% versus 55.6% (P = 0.005) at 6 months by CT‐angiography, and 2.9% versus 18.9% (P = 0.033), 18.2% versus 50.0% (P = 0.006), and 34.4% versus 61.1% (P = 0.028) at 3, 6, and 12 months by sonography, respectively. Clinically, patients in the stent group reported a significantly higher maximum walking capacity compared with the PTA group at 6 and 12 months. Conclusion: In this randomized multicenter trial, primary stenting with a self‐expanding nitinol stent for treatment of intermediate length SFA disease resulted morphologically and clinically superior midterm results compared with balloon angioplasty with optional secondary stenting. © 2009 Wiley‐Liss, Inc.
Medicinal Chemistry Teaching and Training: A Continuous Adaptation
Authors: Timmerman Henk , de Souza Noel J.
Published: May 2009

Bridging the gap: The differences between medicinal chemistry at the industrial and academic levels raises the question: Is there a significant gap between the two spheres that requires attention, or should such differences be deemed natural, without the need to close the gap? Herein we provide perspectives on this issue, based in part on opinions expressed at a forum discussion held at ISMC 2008 in Vienna.

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Liver function test abnormalities in anorexia nervosa—Cause or effect
Authors: Narayanan Vignesh , Gaudiani Jennifer L. , Harris Robert Hill , Mehler Philip S.
Published: May 2009

Objective:

Two females with severe anorexia nervosa (BMI of 10) were seen with marked abnormalities in their liver function tests before the initiation of refeeding. These paradoxically resolved with progressive refeeding and weight restoration.

Method:

Clinical observation during regimented medical stabilization and refeeding of two patients with severe anorexia nervosa with frequent monitoring of liver function tests.

Results:

Normalization of liver function tests ensued as caloric intake increased and weight gain progressed.

Discussion:

Although classically liver function test elevations occur during refeeding, as a manifestation of excessive calories and fat deposition in the liver, they may also be elevated due to severe malnutrition before refeeding has commenced and improved as refeeding occurs. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2010
Statins inhibit NK‐cell cytotoxicity by interfering with LFA‐1‐mediated conjugate formation
Authors: Raemer Patrick C. , Kohl Kristine , Watzl Carsten
Published: May 2009

Inhibitors of the 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, commonly referred to as statins, are inhibitors of cholesterol biosynthesis. They are broadly used for treating hypercholesterolemia and for prevention of cardio‐ and cerebrovascular diseases. Recent publications show that statins also act as immunomodulatory drugs. Here, we show that lipophilic statins inhibit NK‐cell degranulation and cytotoxicity. This effect was reversible by addition of substrates of isoprenylation, but not by addition of cholesterol. In NK‐target cell conjugates intracellular Ca2+ flux was unaffected by statin treatment. However, statins strongly reduced the amount of conjugate formation between NK and target cells. This inhibition was paralleled by a statin‐dependent inhibition of LFA‐1‐mediated adhesion and a reduction of NK‐cell polarization. This demonstrates that statins impair the formation of effector–target cell conjugates resulting in the disruption of early signaling and the loss of NK‐cell cytotoxicity.
Synthesis, Structure, Conductivity, and Calculated Nonlinear Optical Properties of Two Novel Bis(triphenylphosphane)copper(I) Dithiocarbamates
Authors: Kumar Abhinav , Mayer‐Figge Heike , Sheldrick William S. , Singh Nanhai
Published: May 2009

A centrosymmetric binuclear [{Cu(PPh3)2}2(piperzdtc)] (1) [piperzdtc2– = piperazinebis(dithiocarbamate)] and another mononuclear [{Cu(PPh3)2}(BzMedtc)] (2) (BzMedtc– = N‐benzyl‐N‐methyldithiocarbamate) complex have been synthesized and characterized by elemental analyses, IR, 1H, 13C, and 31P NMR spectroscopy and by X‐ray crystallography. The nonlinear optical properties of 2 have been investigated by density functional theory and its electronic absorption bands have been assigned by time‐dependent density functional theory (TD‐DFT). Both complexes are weakly conducting (σrt ≈ 10–8 S cm–1) because of the absence of M···S/S···S intermolecular stacking and exhibit semiconductivity with band gaps of 0.94 and 1.24 eV, respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Crystal Structures and Solution Behavior of Paramagnetic, Trinuclear, Mixed‐Valent Cobalt Complexes with Salen‐Type Ligands
Authors: Mechi Lassaad , Siega Patrizia , Dreos Renata , Zangrando Ennio , Randaccio Lucio
Published: May 2009

New trinuclear mixed‐valent CoIII‐CoII‐CoIII complexes with salen‐type ligands have been synthesized and characterized both in the solid state and in solution. These complexescomprise a central CoCl2 unit connecting two [RCo(4,4′,7,7′tmsalen)] fragments with chlorides acting as bridging ligands between the metals, while the central CoII ion completes its octahedral coordination through the salen oxygen donors. Complex 1 (R = CH2Cl), which has cis Cl ligands at the central CoII ion, has approximate C2 symmetry, whereas the centrosymmetric complex 2 (R = CF3CH2) contains trans Cl ligands (C2h symmetry). Complexes 1 and 2 are paramagnetic with magnetic moments of 4.7 and 4.4 μB, respectively, which indicate the presence of a high‐spin CoII center in the molecule. The 1H NMR spectra, which spread over a range of nearly 190 ppm, are consistent with the presence of both cis and trans isomers in solution (with cis being the prevailing species), and indicate that exchange is slow on the NMR time‐scale. Isotropically shifted 1H NMR signals have been fully assigned by comparison with those of appropriately substituted complexes and by T1 measurements and 2D exchange experiments (EXSY). The K constant for the trans [rlarr2] cis equilibrium, as evaluated from the 1H NMR signal intensity ratio at various temperatures, has allowed us to estimate, at least qualitatively, the thermodynamic parameters ΔH° and ΔS°.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)