bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface infusion of gold nanoparticles into processed thermoplastics
Authors: Lentz Daniel M. , Pyles Robert A. , Hedden Ronald C.
Published: September 2009

Stable dispersions of gold (Au0) nanoparticles are produced in a few commercially important thermoplastics using a novel surface infusion technique. The thermoplastic article is immersed in a dilute solution of HAuCl4 in a ternary solvent mixture held well below the melt‐processing temperature of the plastic. Rapid infusion of plasticizing solvents and HAuCl4 is achieved for several thermoplastic polyurethane elastomers and an acrylic‐pyrrolidinone copolymer. A second infusion of triethylamine, a reducing agent, produces Au0 nanoparticles in a surface layer of (10–30 μm) depth. Precipitation of Au0 nanoparticles is arrested by the high viscosity of the plasticized polymer matrix, resulting in a stable dispersion, but formation of aggregates is possible in some plastics. The Au0 particle size distribution can be manipulated by changing processing conditions that affect the formation of aggregates, such as the concentrations of HAuCl4 and plasticizers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A facile synthesis method of nickel nanotubes assisted by polyethylene glycol
Authors: Tao Feifei , Gao Cuiling , Xu Zheng , Xue Ziling
Published: September 2009

Using an easy and general way, magnetic metal nickel nanotubes are successfully fabricated by adding polyethylene glycol (PEG200, PEG2000, and PEG20000) in the common electrolyte solution combined with electrodeposition technique. This method is very easy, effective, and facile. Especially, the pore wall of the template need not be modified, and their wall thickness can be effectively controlled by adjusting the experimental parameters, such as the electric current density, the concentration of polyethylene glycol, and the electrodeposition time. The possible formation mechanism is proposed. The magnetic measurement of Ni nanotubes indicates that the difference of the polymers used in the preparation does not have a notable effect on their magnetic properties. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Effects of organic encapsulation on the properties of magnetic PLLA/Fe3O4 composites
Authors: Zhang Jing , Yu Demei , Lv Anlin , Xie Yunchuan , Hu Guohe , Liang Honglu , Min Chao
Published: September 2009

Organic‐encapsulated Fe3O4 magnetic microspheres (MMS) were synthesized and used to prepare PLLA (poly (L‐lactic acid))/MMS composites. The effects of organic encapsulation on the mechanical, thermal, and magnetic properties of the composites were investigated. When compared with the PLLA/Fe3O4 composite, the elongation ratio of the PLLA/MMS composite improved significantly (by nearly 300%). Scanning electron microscope (SEM) images of the fracture morphology revealed an interesting “silking” phenomenon within the PLLA/MMS composite, which explains the greatly improved toughness. The decreased crystallinity and increased thermal stability of the PLLA/MMS composite suggest the existence of strong interacting forces between the PLLA molecules and the organic layer of the MMS particles, thereby limiting the mobility of the macromolecular chains. A study of the composites' magnetic properties indicated that the saturation magnetization was determined by the relative Fe3O4 content in the matrix, but not the types of the filling particles. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Study of the molecular orientation heterogeneity in polypropylene injection‐molded parts by Raman spectroscopy
Authors: Martin J. , Margueron S. , Fontana M. , Cochez M. , Bourson P.
Published: September 2009

Polarized Raman microspectroscopy has been used to study oriented‐skin layers induced in injection‐molded isotactic polypropylene (iPP) parts. A method based on the intensity sensitivity of several Raman bands to laser light polarization was employed to estimate the degree of molecular orientation in iPP. The skin‐core molecular orientation heterogeneity in injection‐molded iPP is then evaluated via two different experimental methods. Results show that an in‐depth profile using micro‐Raman confocal technique is as valuable as an edge profile performed on a sample cross‐section because both are correlated with optical microscopy measurements. Both Raman measurements are in good agreement with optical microscopy measurements. The skin development was found to be narrowly related to the shear strain rate at the mold walls. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Preparation of extruded melt‐mixed polypropylene/montmorillonite nanocomposites with inline monitoring
Authors: Bertolino Marcelo K. , Canevarolo Sebastião V.
Published: September 2009

This article advances the use of an inline optical detector to monitor the disaggregation of the montmorillonite (MMT) clay tactoids during the preparation of polypropylene (PP)/MMT nanocomposites via polymer melt compounding. During the exfoliation of the tactoids their size are reduced below the minimum particle size to produce light extinction and so, the signal of the inline detector reduces as the nanosize composite is formed. The measurement is done at the transient state with the MMT clay added as a pulse with constant weight into the PP extrusion melt flow and followed by the optical detector. The data comes out as the common residence time distribution curves having its maximum intensity related to the tactoids average particle size, keeping all other variables constants. The light extinction was measured for composites with different clays (Cloisite® 15A, 30B, Na+, and Sintered 20A) using the same PP grafted with maleic anhydride compatibilizer. The dissaglomeration/exfoliation efficiency increases as: ‘‘Sintered 20A’’ < ‘‘Na+ clay’’ < ‘‘organo‐modified clay’’ < ‘‘organo‐modified clay + compatibilizer’’. The best result is obtained using Cloisite® 15A and Cloisite® 20A following the expected reduction of the particle size obtained during a nanocomposite melt processing. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Nanocomposites of silver nanoparticle and dinonylnaphthalene disulfonic acid‐doped thermoreversible polyaniline gel
Authors: Garai Ashesh , Chatterjee Shreyam , Nandi Arun K.
Published: September 2009

Silver/polyaniline‐dinonylnaphthalene disulfonic acid (PANI‐DNNDSA) gel nanocomposites are prepared from the reduction of silver salt by polyaniline in formic acid medium. Scanning electron micrographs (SEM) indicate the presence of three‐dimensional fibrillar network structure and the silver nanoparticles remain dispersed within the PANI‐DNNDSA fibrillar network. Differential scanning calorimetric (DSC) study shows reversible first‐order phase transition characterizing the composite to behave as a thermoreversible gel. Transmission electron micrographs (TEM) show a decrease of nanoparticle size with increasing AgNO3 concentration. Wide angle X‐ray scattering (WAXS) patterns show lamellar structure in the gel as well as in the gel metal nanocomposites (GMNCs) and the two melting peaks in the DSC patterns correspond to the melting of monolayer and bilayer crystals produced from the interdigitation of DNNDSA tails anchored from PANI chains within the PANI lamella. The above melting points are greater in the GMNCs than that of pure gel indicating the formation of complex melting thermogram with crystallites produced from the anchored surfactants tails at the surface of Ag nanoparticles. The GMNCs show a higher thermal stability than that of pure PANI‐DNNDSA gel. PANI‐DNNDSA gel has an emission peak at 354 nm but fluorescence quenching occurs in the GMNCs and the emission peak becomes red shifted. Also in the UV–vis spectra the π band‐polaron band transition peak shows a red shift and the DC conductivity increases with increasing Ag nanoparticle concentration in the GMNCs. The current (I)–voltage (V) characteristic curves indicate Ohmic nature of conductivity of the gel and the current at the same voltage increases appreciably with increasing Ag nanoparticle concentration. These GMNCs are easily processible due to its thermoreversible nature. So, an easily processible, thermally stable and highly conducting DNNDSA‐doped PANI‐Ag gel nanocomposite with interesting photoluminescent property has been successfully developed suitable for optoelectronic applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A proteomic and transcriptomic view of amino acids catabolism in the yeast Yarrowia lipolytica
Authors: Mansour Soulaf , Bailly Julie , Delettre Jérôme , Bonnarme Pascal
Published: September 2009

The yeast Yarrowia lipolytica has to develop dynamic metabolic adaptation mechanisms to survive within the cheese habitat. The availability of amino acids (AAs) is of major importance for microbial development and/or aroma production during cheese ripening. Using 2‐D protein gel electrophoresis, we analyzed the adaptation mechanisms of Y. lipolytica for AAs limitation or supplementation in a batch culture containing lactate as a carbon source. Proteome analyses allow the identification of 34 differentially expressed proteins between the culture conditions. These analyses demonstrated that prior to the AAs addition, mainly proteins involved in the oxidative stress of the yeast were induced. Following the AAs addition, yeast cells reorganize their metabolism toward AAs catabolism and also generate a higher induction of proteins related to carbon metabolism and proteins biosynthesis. Using real‐time reverse transcription PCR, we re‐evaluated the expression of genes encoding proteins involved in these processes. The expression levels of the genes were in accordance with the proteomic results, with the up‐regulation of genes encoding a branched‐chain amino transferase BAT2, a pyruvate decarboxylase PDC6 and an Hsp70 protein SSZ1 involved in protein biosynthesis. A volatile compound analysis was also performed, and increased production of dimethyldisulfide from methionine and 3‐methyl‐butanal from leucine was observed in media supplemented with AAs.
Al Top Cathode Deposition on OLED Using DC Magnetron Sputtering
Authors: Gil Tae Hyun , May Christian , Lakner Hubert , Leo Karl , Keller Stefan
Published: September 2009

We fabricated OLEDs having the evaporated Yb cathode and the sputtered Al cathode. Magnetron sputtering is a versatile deposition method, but the energetic particles during sputtering process can damage the underlying organic layers. We applied various process parameters to explain the role of Ar neutrals quoting the former researches. OLEDs showed almost comparable degradation under the discharge voltage of 300 V, but serious degradations were found at the discharge voltage of over 300 V and the low process pressure. The degradations influenced on the lifetime of OLED, and the measured luminance decay was much larger than the OLED having the evaporated Yb cathode due to the high leakage currents.
Molecular mechanism of allosteric communication in the human PPARα‐RXRα heterodimer
Authors: Venäläinen Tuomas , Molnár Ferdinand , Oostenbrink Chris , Carlberg Carsten , Peräkylä Mikael
Published: September 2009

The peroxisome proliferator‐activated receptor α (PPARα) is a nuclear receptor (NR) that forms a heterodimeric transcription factor complex with the retinoid X receptor α (RXRα). The phenomenon that the heterodimer can be activated by both PPARα and RXRα ligands, while both ligands have a synergistic effect on its activity suggests that there is an allosteric communication within the heterodimer. In this study, the molecular mechanism of this allosteric signaling was studied by molecular dynamics (MD) simulations and some of the residues involved in this communication were tested experimentally. Multiple MD simulations were done for the PPARα‐RXRα heterodimer ligand‐binding domains (LBDs) without ligands, with agonistic ligand bound to RXRα or PPARα, and ligand bound to both receptors. Fluctuation calculations and structural clustering analysis of the heterodimer MD simulations showed that ligand binding to RXRα decreases fluctuations of large parts of PPARα, most notably helices 3 and 4 at the coactivator binding site, which presumably stabilizes the coactivator binding to heterodimer complex. The dynamics of helix 8–9 loop and helix 10/11 located at the heterodimeric interface were affected by RXRα ligand binding, suggesting that these parts of the dimer are involved in allosteric communication. Experimental data complemented this view by showing that a large set of residues at the heterodimerization surface has a role in the communication. These results provided evidence that RXRα ligand binding‐induced stabilization of PPARα coactivator binding site has a role in the permissive and synergistic activation of the PPARα‐RXRα heterodimer. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Effect of synthesis process on the Young's modulus of titanate nanowire
Authors: Chang Ming , Deka Juti Rani , Chang Feng Cheng
Published: September 2009

Nanocrystalline materials have attracted a great deal of attention because of their intriguing size‐/shape‐dependent properties. Titanate nanowires have been synthesized from titania (TiO2) nanoparticles using conventional hydrothermal process. Young's moduli of as‐prepared titanate nanowires have been determined in situ from the buckling instability of the nanowires due to application of axial compressive load using a nanomanipulator inside a scanning electron microscope. Based on Euler's buckling model, the Young's moduli of the nanowires are determined to be 32 ± 11 GPa. The obtained Young's moduli have been compared to that of the titanate nanowires prepared with microwave hydrothermal process to study the effect of synthesis process on the mechanical behavior of nanomaterials. The prolonged holding time of a conventional hydrothermal process helps in the significant enhancement of the Young's modulus of nanowire in comparison to that prepared with microwave hydrothermal process.
Effective surface passivation of crystalline silicon using ultrathin Al2O3 films and Al2O3/SiNx stacks
Authors: Schmidt Jan , Veith Boris , Brendel Rolf
Published: September 2009

We measure surface recombination velocities (SRVs) below 10 cm/s on p‐type crystalline silicon wafers passivated by atomic–layer–deposited (ALD) aluminium oxide (Al2O3) films of thickness ≥10 nm. For films thinner than 10 nm the SRV increases with decreasing Al2O3 thickness. For ultrathin Al2O3 layers of 3.6 nm we still attain a SRV < 22 cm/s on 1.5 Ω cm p‐Si and an exceptionally low SRV of 1.8 cm/s on high‐resistivity (200 Ω cm) p‐Si. Ultrathin Al2O3 films are particularly relevant for the implementation into solar cells, as the deposition rate of the ALD process is extremely low compared to the frequently used plasma‐enhanced chemical vapour deposition of silicon nitride (SiNx). Our experiments on silicon wafers passivated with stacks composed of ultrathin Al2O3 and SiNx show that a substantially improved thermal stability during high‐temperature firing at 830 °C is obtained for the Al2O3/SiNx stacks compared to the single‐layer Al2O3 passivation. Al2O3/SiNx stacks are hence ideally suited for the implementation into industrial‐type silicon solar cells where the metal contacts are made by screen‐printing and high‐temperature firing of metal pastes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective imaging of positively charged polar and nonpolar lipids by optimizing matrix solution composition
Authors: Sugiura Yuki , Setou Mitsutoshi
Published: September 2009

Previous studies have shown that matrix‐assisted laser desorption/ionization–imaging mass spectrometry (MALDI‐IMS) is useful for studying the distribution of various small metabolites, particularly lipids. However, in this technique, selective ionization of the target molecules is imperative, particularly when analyzing small molecules. Since the sample clean‐up procedures available for the MALDI‐IMS of small metabolites are limited, the tissue sample will contain numerous molecular species other than the target molecules. These molecules will compete for ionization resulting in severe ion suppression. Hence, it is necessary to develop and optimize a sample preparation protocol for the target molecules. In this study, through model experiments using reference compounds, we optimized the composition of the matrix solution used for positively charged lipids in terms of the concentration of the organic solvent and presence/absence of alkali metal salts. We demonstrated that a high concentration of organic solvent in the matrix solution favors the preferential detection of lipids over peptides. The presence of alkali metal salts in the matrix solution was favorable for the detection of polar lipids, while a salt‐free matrix solution was suitable for the detection of nonpolar lipids. Furthermore, potassium salts added to the matrix solution caused merging of various lipid adducts (adducts with proton, sodium, and potassium) into one single potassiated species. Using the optimized protocols, we selectively analyzed phosphatidylcholine (PC) and triacylglycerol (TG) with different fatty acid compositions in a rat kidney section. Copyright © 2009 John Wiley & Sons, Ltd.
Characterization of S‐thiolation on secreted proteins fromE. coliby mass spectrometry
Authors: Liu Peiran , Tarnowski Malloree A. , O'Mara Brian W. , Wu Wei , Zhang Haiying , Tamura James K. , Ackerman Michael S. , Tao Li , Grace Michael J. , Russell Reb J.
Published: September 2009

S‐thiolation is a reversible post‐translational modification in which thiol metabolites of low molecular masses are linked to protein sulfhydryl groups through disulfide bonds. This modification is commonly observed in recombinant proteins secreted fromE. colicells. Since it can alter protein functions and introduce molecular heterogeneity, S‐thiolation is undesirable for recombinant protein production. To date, few published studies have characterized thiol modifiers or investigated the mechanism of S‐thiolation in recombinant proteins. In this work, reversed‐phase liquid chromatography and mass spectrometry were used to characterize four of the most abundant thiol modifiers on recombinant proteins secreted fromE. coliBL21 (DE3) strain. These thiol modifiers have been identified as glutathione, 4‐phosphopantetheine, gluconoylated glutathione, and dephosphorylated coenzyme A. S‐thiolation by these thiol modifiers increases protein mass by 305, 356, 483, and 685 Da, respectively. These specific mass increases can be used as markers for identifying S‐thiolation in recombinant proteins. Copyright © 2009 John Wiley & Sons, Ltd.
Derivatization aids in the determination of end groups in poly(alkylene glycol)s by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Borisov Roman S. , Polovkov Nikolai Yu. , Zaikin Vladimir G.
Published: September 2009

A method for end‐group characterization by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry following preliminary derivatization with N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) and capryloyl chloride is described and applied to poly(alkylene glycol)s. The MALDI mass spectra of the products revealed peaks of sodiated derivative cations, whose shift by the respective increments allowed the determination of the number of end functional groups with active hydrogens. This approach is particularly efficient for the distinction of cyclic and linear dehydration products among minor components. Copyright © 2009 John Wiley & Sons, Ltd.
Formation of Resistant Starch in Corn Starch and Estimation of its Content from Physicochemical Properties
Authors: Kim Sung‐Kon , Kwak Jae‐Eun
Published: September 2009

The effect of autoclaving temperatures (100‐120°C) on yields of enzyme‐resistant starch (RS) from normal corn starch and the physicochemical properties of autoclaved‐cooled starches were studied. The RS content increased linearly with increasing autoclaving temperature (R2 = 0.993) and the number of autoclaving‐cooling cycles at an autoclaving temperature of 120°C. The effect of the number of autoclaving‐cooling cycles was more pronounced than that of temperature. The swollen starch weight measured at 60°C slightly increased as the RS content increased, and then drastically decreased with the continous increase of the RS content (R2 = ‐0.969). As the RS content increased, all parameters of Rapid Visco Analyser (RVA) viscosity except breakdown decreased. Log RVA peak viscosity showed a negative correlation with the RS content (R2 = ‐0.986). The enthalpy in the differential scanning calorimetry (DSC) endotherm corresponding to the transitions of RS linearly increased as the RS content increased (R2 = 0.988). The RS content of the heat‐treated starch estimated from the relationship between RS content and swollen starch weight at 60°C, log RVA peak viscosity or DSC enthalpy was in good agreement with that determined with the standard method.
Effect of Fatty Acid Addition on the Properties of Biopolymer Films Based on Lipophilic Maize Starch and Gelatin
Authors: Fakhouri Farayde M. , Fontes Luciana C. B. , Innocentini‐Mei Lucia H. , Collares‐Queiroz Fernanda P.
Published: September 2009

In the presented work, composed layer films based on lipophilic starch and gelatin were produced containing different amounts of fatty acids (palmitic, lauric, myristic, capric, caproic and caprylic); i.e., 5, 15, 25 and 50%, using sorbitol as the plasticizer. All films were prepared by casting in an acrylic plate and their barrier properties (vapor permeability), as well as their mechanical (tensile strength and elongation), physicochemical (water solubility) and physical (opacity and thickness) properties were measured. The addition of fatty acids to the biopolymer films increased their thickness, opacity and elongation. On the other hand, the addition of fatty acids decreased the tensile strength and water vapor permeability of the biopolymer films for all formulations studied. The fatty acid concentration found to be effective in reducing the biopolymer film permeability varied between 15 and 25%.
Impact of Pre‐Processing of Montmorillonite on the Properties of Melt‐Extruded Thermoplastic Starch/ Montmorillonite Nanocomposites
Authors: Wang Xuechen , Zhang Xingxiang , Liu Haihui , Wang Ning
Published: September 2009

A simple and environmentally‐friendly processing method was used to prepare thermoplastic starch (TPS)/ montmorillonite (MMT) nanocomposites. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) demonstrated that glycerol could enlarge the d‐spacing and destruct the layered structure of MMT effectively during the pre‐processing of MMT. So the enlarged d‐spacing and fragmentized platelets of glycerol activated‐MMT were a precondition to form intercalated or exfoliated TPS‐based nanocomposites during the melt extrusion processing. These highly dispersive and compatible TPS/activated‐MMT nanocomposites had increased thermal stability and tensile properties as compared with non‐activated composites. Especially, the tensile strength of nanocomposites could be enhanced to 8.6 MPa, the improvement was about two times the initial tensile strength of TPS.
More significant and intentional learning in the economics classroom
Authors: Miners Laurence , Nantz Kathryn
Published: September 2009

By using Fink's taxonomy to shape new learning goals and creating new learning and assessment activities, two teachers succeeded in raising students' awareness of the value of their courses and enabled them to become more reflective learners in the process.
Integrating big questions with real‐world applications: Gradual redesign in philosophy and art history
Authors: Rose Marice , Torosyan Roben
Published: September 2009

Two humanities professors shift from the rut of readings, memorization, and papers to having students ask personalized questions and make concepts relevant outside the classroom.
Still learning
Authors: Fink L. Dee
Published: September 2009

In 2007, Fink taught a graduate‐level course, Preparing for College‐Level Teaching, at the University of Oklahoma. This experience generated three specific lessons worth sharing.
Lessons we can learn from the voices of experience
Authors: Fink Arletta Knight , Fink L. Dee
Published: September 2009

This chapter reviews the preceding chapters and distills from that collection answers to three questions that all good teachers need to ask and answer.
Confidence of expert ultrasound operators in making a diagnosis of adnexal tumor: effect on diagnostic accuracy and interobserver agreement
Authors: Yazbek J. , Ameye L. , Testa A. C. , Valentin L. , Timmerman D. , Holland T. K. , Van Holsbeke C. , Jurkovic D.
Published: September 2009

Objective

To assess the degree of confidence with which expert ultrasound operators make a diagnosis of benign, borderline and invasive malignant ovarian tumors and its effect on diagnostic accuracy and interobserver agreement.

Method

Digitally stored static two‐dimensional B‐mode images of representative cases of benign, borderline and invasive malignant ovarian tumors were independently assessed by three expert ultrasound operators who had not performed the original real‐time ultrasound examination. The experts classified the tumors as benign, borderline or invasive malignant and they also indicated the degree of confidence with which they made the diagnosis (certain, probable and uncertain). The diagnostic accuracy and interobserver agreement, in differentiating benign, borderline and invasive malignant ovarian tumors, were calculated depending on the level of confidence with which the diagnosis was made.

Results

One hundred and sixty‐six cases were included in the final data analysis. The diagnostic accuracy of all three experts decreased with decreasing level of confidence. Interobserver agreement between any two experts was very high when they were certain of the diagnosis (rates of agreement 98%, 99% and 100%), but it was significantly lower with a moderate level of confidence (rates of agreement 78%, 71% and 76%) (P < 0.01 for any two experts). The agreement in both diagnosis and confidence was lowest in cases of borderline ovarian tumors compared to benign and primary invasive lesions.

Conclusions

The accuracy of expert ultrasound operators using pattern recognition depends on the degree of certainty with which the diagnosis is made. Interobserver variability is also influenced by the operators' confidence in making the diagnosis. Our findings suggest that the level of confidence with which the diagnosis is made should be included in the ultrasound report. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Nanoparticles in sentinel lymph node mapping
Authors: Ravizzini Gregory , Turkbey Baris , Barrett Tristan , Kobayashi Hisataka , Choyke Peter L.
Published: September 2009

The lymph nodes and lymphatic vessels are more difficult to access than most vascular structures. Interstitial injection of imaging agents is often necessary to opacify the lymphatics. Traditionally, radionuclide methods of sentinel node imaging have dominated this field, however, limitations in resolution and exposure to radiation have encouraged the development of newer imaging methods. Among these are magnetic resonance lymphography in which a Gadolinium labeled nanoparticle is injected and imaged providing superior anatomic resolution and assessment of lymphatic dynamics. Optical imaging employing various nanoparticles including quantum dots also provide the capability of mapping each lymphatic basin in another “color”. Taken together this “toolbox” of lymphatic imaging agents is poised to improve our understanding of the lymphatic system Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery
2,5,8‐Trihydrazino‐s‐heptazine: A Precursor for Heptazine‐based Iminophosphoranes
Authors: Saplinova Tatyana , Bakumov Vadym , Gmeiner Tobias , Wagler Jörg , Schwarz Marcus , Kroke Edwin
Published: September 2009

The title compound  C6N7(NHNH2)3 (1) was obtained from melem C6N7(NH2)3 or melon [C6N7(NH2)NH]n and hydrazine by an autoclave synthesis. Upon treatment with a 10 % HCl solution it is transformed into the trihydrochloride  [C6N7(NHNH3)3]Cl3 (2). Compounds 1 and 2 were analysed with 13C NMR, 15N NMR, FTIR and Raman spectroscopy. Furthermore, the single‐crystal X‐ray structure of the pentahydrate of 2 is reported (P\bar{1}, a = 674.96(3), b = 1214.17(6), c = 1272.15(6) pm, α = 66.288(2)°, β = 75.153(2)°, γ = 80.420(2)°, V = 920.30(8)·106 pm3, Z = 2, T = 90(2) K). The thermal decomposition of 1 and 2 was investigated with TG/DTA. Reaction of 1 with NaNO2/HCl yields triazido‐s‐heptazine, C6N7(N3)3 (3). Tris(tri‐n‐butylphosphinimino)‐s‐heptazine (4) was synthesised from 3 and characterised by means of 13C, 31P, 1H NMR, FTIR and MALDI‐TOF spectroscopy. Similar to s‐heptazine derivative 3, compounds 1 and 4 are precursors for graphitic carbon nitrides, which have attracted considerable attention recently, and to various potential applications, such as flame retardants and (photo) catalysis.
Management of Liver Trauma
Authors: Badger S. A. , Barclay R. , Campbell P. , Mole D. J. , Diamond T.
Published: September 2009

Background

Blunt and penetrating liver trauma is common and often presents major diagnostic and management problems.

Methods

A literature review was undertaken to determine the current consensus on investigation and management strategies.

Results

The liver is the most frequently injured organ following abdominal trauma. Immediate assessment with ultrasound has replaced diagnostic peritoneal lavage in the resuscitation room, but computerised tomography remains the gold standard investigation. Nonoperative management is preferred in stable patients but laparotomy is indicated in unstable patients. Damage control techniques such as perihepatic packing, hepatotomy plus direct suture, and resectional debridement are recommended. Major complex surgical procedures such as anatomical resection or atriocaval shunting are now thought to be redundant in the emergency setting. Packing is also recommended for the inexperienced surgeon to allow control and stabilisation prior to transfer to a tertiary centre. Interventional radiological techniques are becoming more widely used, particularly in patients who are being managed nonoperatively or have been stabilised by perihepatic packing.

Conclusions

Management of liver injuries has evolved significantly throughout the last two decades. In the absence of other abdominal injuries, operative management can usually be avoided. Patients with more complex injuries or subsequent complications should be transferred to a specialist centre to optimise final outcome.
Laparoscopic liver surgery: 8 years of multicenter Spanish register
Authors: Cugat Esteve , Pérez‐Romero Noelia , Rotellar Fernando , Suárez Miguel A. , Gastaca Mikel , Artigas Vicente , Olsina Jorge‐Juan , Noguera José , Martínez Sagrario , Moreno‐Sanz C. , Figueras Joan , Herrera Javier , Díaz Hermógenes , Caballé Jordi , Pereira Fernando
Published: September 2009

Background

To present the data of laparoscopy in liver surgery and to assess the real indications and outcomes of this kind of approach.

Methods

From February 2000 to March 2008, a prospective study was performed on 182 patients from 15 Spanish surgical centres.

Results

A total of 308 lesions was collected. The mean age was 57 years old, and 61.5% were female. Among patients with cystic lesions we found: 45 simple cysts, 19 policystic diseases, 12 hydatidic cysts and 2 cystoadenomas. Among solid lesions (n = 104), we found 34 patients with benign pathology (12 focal nodular hyperplasia, 10 adenomas, 7 haemangyomas and 5 other lesions) and 70 with malignant pathology (38 metastases, 29 hepatocellular carcinomas, 2 cholangiocarcinomas and 1 lymphoma). The global rate of conversion was 8.8%. The global morbidity rate was 14.8%, and 5 of them required re‐intervention.

Conclusions

Nowadays there are strong criteria for patients being submitted to laparoscopy procedures based both on type and location features. The postoperative morbidity rate is low, also for hepatocellular carcinoma in cirrhotic liver. In case of malignant pathology, we think the use of ultrasonography is mandatory to obtain a free margin, which implies a long‐term survival rate.
Subacromial Injection Improves Deltoid Firing in Subjects with Large Rotator Cuff Tears
Authors: Cordasco Frank A. , Chen Neal C. , Backus Sherry I. , Kelly Bryan T. , Williams Riley J. , Otis James C.
Published: September 2009

Previous studies demonstrate that scapulohumeral mechanics improve after subacromial injection. However, it is unclear how injection affects muscle firing. Forty-one subjects with two-tendon rotator cuff tears and 23 volunteer subjects with normal rotator cuffs documented by ultrasonography were examined. Electromyographic activity from 12 muscles was collected during ten functional tasks. Nine symptomatic subjects with rotator cuff tears underwent subacromial injection of anesthetic and underwent repeat electromyographic examination. Subjects with rotator cuff tears demonstrate global electromyographic differences when compared to normal controls. Asymptomatic subjects with rotator cuff tears had significantly increased anterior deltoid firing when compared to symptomatic counterparts during forward shoulder elevation. After subacromial injection, symptomatic subjects demonstrate increased anterior deltoid firing. Previous in vitro and in vivo studies have suggested that pain leads to deltoid inhibition and that subacromial injection leads to improved deltoid firing and, subsequently, improved shoulder function. This study provides direct evidence that subacromial injection improves deltoid firing in symptomatic subjects with rotator cuff tears. These findings reinforce the concept that deltoid inhibition resulting from pain is an important component of the motor disability associated with rotator cuff tears.
Synthesis, Characterization, and Microwave Absorption Property of the SnO2Nanowire/Paraffin Composites
Authors: Feng HT , Zhuo RF , Chen JT , Yan D , Feng JJ , Li HJ , Cheng S , Wu ZG , Wang J , Yan PX
Published: September 2009

In this article, SnO2nanowires (NWs) have been prepared and their microwave absorption properties have been investigated in detail. Complex permittivity and permeability of the SnO2NWs/paraffin composites have been measured in a frequency range of 0.1–18 GHz, and the measured results are compared with that calculated from effective medium theory. The value of maximum reflection loss for the composites with 20 vol.% SnO2NWs is approximately −32.5 dB at 14 GHz with a thickness of 5.0 mm.
Hydrothermal Growth and Application of ZnO Nanowire Films with ZnO and TiO2Buffer Layers in Dye-Sensitized Solar Cells
Authors: Yang Weiguang , Wan Farong , Chen Siwei , Jiang Chunhua
Published: September 2009

This paper reports the effects of the seed layers prepared by spin-coating and dip-coating methods on the morphology and density of ZnO nanowire arrays, thus on the performance of ZnO nanowire-based dye-sensitized solar cells (DSSCs). The nanowire films with the thick ZnO buffer layer (~0.8–1 μm thick) can improve the open circuit voltage of the DSSCs through suppressing carrier recombination, however, and cause the decrease of dye loading absorbed on ZnO nanowires. In order to further investigate the effect of TiO2buffer layer on the performance of ZnO nanowire-based DSSCs, compared with the ZnO nanowire-based DSSCs without a compact TiO2buffer layer, the photovoltaic conversion efficiency and open circuit voltage of the ZnO DSSCs with the compact TiO2layer (~50 nm thick) were improved by 3.9–12.5 and 2.4–41.7%, respectively. This can be attributed to the introduction of the compact TiO2layer prepared by sputtering method, which effectively suppressed carrier recombination occurring across both the film–electrolyte interface and the substrate–electrolyte interface.
Self-Assembled Polymeric Micellar Nanoparticles as Nanocarriers for Poorly Soluble Anticancer Drug Ethaselen
Authors: Li Xinru , Yang Zhuoli , Yang Kewei , Zhou Yanxia , Chen Xingwei , Zhang Yanhui , Wang Fei , Liu Yan , Ren Lijun
Published: September 2009

A series of monomethoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA) diblock copolymers were synthesized, and mPEG-PLA micelle was fabricated and used as a nanocarrier for solubilization and delivery of a promising anticancer drug ethaselen. Ethaselen was efficiently encapsulated into the micelles by the dialysis method, and the solubility of ethaselen in water was remarkably increased up to 82 μg/mL before freeze-drying. The mean diameter of ethaselen-loaded micelles ranged from 51 to 98 nm with a narrow size distribution and depended on the length of PLA block. In vitro hemolysis study indicated that mPEG-PLA copolymers and ethaselen-loaded polymeric micelles had no hemolytic effect on the erythrocyte. The enhanced antitumor efficacy and reduced toxic effect of ethaselen-loaded polymeric micelle when compared with ethaselen-HP-β-CD inclusion were observed at the same dose in H22human liver cancer cell bearing mouse models. These suggested that mPEG-PLA polymeric micelle nanoparticles had great potential as nanocarriers for effective solubilization of poorly soluble ethaselen and further reducing side effects and toxicities of the drug.
Probing Nucleation Mechanism of Self-Catalyzed InN Nanostructures
Authors: Xu Guowei , Li Zhuangzhi , Baca Javier , Wu Judy
Published: September 2009

The nucleation and evolution of InN nanowires in a self-catalyzed growth process have been investigated to probe the microscopic growth mechanism of the self-catalysis and a model is proposed for high pressure growth window at ~760 Torr. In the initial stage of the growth, amorphous InN
x
microparticles of cone shape in liquid phase form with assistance of an InN
x
wetting layer on the substrate. InN crystallites form inside the cone and serve as the seeds for one-dimensional growth along the favorable [0001] orientation, resulting in single-crystalline InN nanowire bundles protruding out from the cones. An amorphous InN
x
sheath around the faucet tip serves as the interface between growing InN nanowires and the incoming vapors of indium and nitrogen and supports continuous growth of InN nanowires in a similar way to the oxide sheath in the oxide-assisted growth of other semiconductor nanowires. Other InN 1D nanostructures, such as belts and tubes, can be obtained by varying the InN crystallites nucleation and initiation process.
Green tea (Camellia sinensis) catechins and vascular function
Authors: Moore Rosalind J. , Jackson Kim G. , Minihane Anne M.
Published: September 2009

The health benefits of green tea (Camellia sinensis) catechins are becoming increasingly recognised. Amongst the proposed benefits are the maintenance of endothelial function and vascular homeostasis and an associated reduction in atherogenesis and CVD risk. The mounting evidence for the influential effect of green tea catechins on vascular function from epidemiological, human intervention and animal studies is subject to review together with exploration of the potential mechanistic pathways involved. Epigallocatechin-3-gallate, one of the most abundant and widely studied catechin found in green tea, will be prominent in the present review. Since there is a substantial inconsistency in the published data with regards to the impact of green tea catechins on vascular function, evaluation and interpretation of the inter- and intra-study variability is included. In conclusion, a positive effect of green tea catechins on vascular function is becoming apparent. Further studies in animal and cell models using physiological concentrations of catechins and their metabolites are warranted in order to gain some insight into the physiology and molecular basis of the observed beneficial effects.
The birth weight of rabbits born after heterospermic insemination
Authors: Beatty R. A.
Published: September 2009

1. Two rabbit sires were used for insemination of sixty-eight females. Insemination was either homospermic (one sire at a time) or heterospermic (mixed semen from the two sires). Each offspring could be traced to its sire by genetic marks. The sires differed in weight and were known to give offspring differing in mature weight and named Large and Small offspring. The object of study was the birth weight of these offspring in logarithmic transformation.

2. After heterospermic insemination, there was no evidence of any real ‘heterospermic vigour’ in the average birth weight of the litter as a whole.

3. After heterospermic insemination, the difference in birth weight between the two kinds of offspring was accentuated (enhancement effect). This confirms a previous experiment.

4. The enhancement effect is ascribed to competition among embryos. It is not attributable to postulated changes in the gestation period. It appears to arise from an increase in the birth weight of Large offspring, together with a possible decrease in the birth weight of Small offspring. These changes in birth weight are attributable to changes in prenatal growth rate.

5. The bearing of this work on Russian experiments with heterospermie insemination is discussed.
Heterokaryon formation in Coprinus lagopus
Authors: Swiezynski K. M. , Day P. R.
Published: September 2009

1. The four possible kinds of heterokaryon of Coprinus lagopus with no, one or both mating-type factors in common (dikaryon, common A, common B and common AB) were produced. Analysis of hyphal tips of common A and common AB heterokaryons has shown that both nuclei may be present in the same hypha.

2. All four heterokaryons are prototrophic when synthesized from two auxotrophic components with different requirements.

3. When synthesized in this way compatible heterokaryons were stable in all tests, but the other heterokaryons showed different degrees of stability. Common B heterokaryons were the most stable and rarely gave rise to monokaryotic mycelia. Dissociation of the common A and the common AB heterokaryon into either component took place much more easily.

4. Comparisons of the growth-rates of wild-type heterokaryons on complete medium show that common A heterokaryons are less vigorous, and dikaryons more vigorous than their monokaryon components. On minimal medium both compatible and common A heterokaryons are less vigorous than their wild-type monokaryon components. The possible reasons for this are discussed.

5. Fruit-bodies have been obtained from both common A and common B heterokaryons. Both types showed normal segregation at the heterozygous locus (B or A), but showed in addition the segregation of new reactions at the ‘homozygous’ locus.
Four new half-and-half mosaic fowls
Authors: Cock A. G.
Published: September 2009

Two mosaic birds are described, from a sex-linked F1cross (Rhode Island Red ♂ × Light Sussex ♀). They are sexually normal males and full brothers. Each has the following abnormalities on one side of the body: absence of the maternal dominantsS(silver, sex-linked),W(white skin) andCo(Columbian restriction of black), and reduction in size. In one case all the melanocytes appear to be derived from the smaller side, so that the plumage pattern is identical on the two sides; in the other there is a minor deviation (modified expression ofCo) from normal F1plumage pattern on the larger side. Mated to Brown Leghorn hens, both mosaics bred as normal F1males, with no evidence of germinal mosaicism. Over thirty full sibs were all found to be normal.

A purely paternal origin of the smaller side appears to be excluded in both cases by the lack of striping in the down, and by minor deviations from normal Brown Leghorn phenotype in adult plumage pattern. Origin by some kind of maldistribution of chromosomes at first cleavage division would require the X-chromosome and possibly as many as three autosomes to be affected simultaneously.

Two further unrelated crossbred mosaic males are described. Each has yellow skin (w) on one side of the body. In one case this is accompanied by a slight difference in plumage pattern, reduction in size and abnormal proportions in the limb bones; in the other merely by a slight reduction in size. Loss or non-disjunction of a single chromosome at first cleavage division is a possible explanation of these.
Discussion on the mutagenic effects of alkylating agents
Authors: Auerbach C.
Published: September 2009

Recently, a publication under this title has been distributed by Drs O. G. and M. J. Fahmy. On top of every page, it carries my name and not that of the authors. This has already resulted in its summary having been printed mistakenly as ‘author's summary’ of a paper of mine in Biological Abstracts. Since this curious publication is likely to lead to more confusion, its origin is explained below.
Maternal effects on the rate of egg development inDrosophila subobscura
Authors: Clarke Jean M. , Smith J. Maynard , Travers Pamela
Published: September 2009

The time in hours from laying to hatching at 17°C. has been measured for eggs from four inbred lines ofDrosophila subobscura, and also for F1eggs, and for eggs obtained by crossing F1hybrids to unrelated inbred lines and to unrelated F1hybrids.

Eggs laid by females of a given genotype have a characteristic rate of development, which, with one exception, is not greatly influenced by the genotype of the male parent. F1hybrid females laid eggs which were more uniform in hatching time than eggs laid by inbred females, and which developed more rapidly than eggs laid by three of the four kinds of inbred female studied. The slowest-developing eggs were laid by females from theNFSinbred line, a line originally selected for slow development from egg to adult.

The male parent, and hence the zygotic nucleus, had an appreciable effect on the rate of egg development only for eggs laid byNFSfemales; these eggs developed more rapidly if fertilized by sperm from an unrelated male.
Genetics of plasma transferrins in the mouse
Authors: Cohen B. L.
Published: September 2009

1. The plasma proteins of six inbred strains of mice have been studied, using starch-gel electrophoresis.

2. The existence of two alternative plasma transferrin (β-globulin) phenotypes has been demonstrated. Five of the strains have one of these and one strain has the other. Each of the two transferrin patterns comprises three (or possibly only two) electrophoretic bands. The two patterns differ in all of these bands.

3. The two transferrin types recognized are determined by a pair of allelic, autosomal genes (designatedTrfAandTrfB). The TrfA phenotype (CBA strain) is determined by the genotypeTrfA/TrfA, and the TrfB phenotype (A, C57BL, JU, KL, RIII strains) by the genotypeTrfB/TrfB. The phenotype TrfAB, of the heterozygote (genotypeTrfA/TrfB), is distinguishable and shows four (or possibly only three) bands. In this way it closely resembles a mixture of equal parts of TrfA and TrfB plasma.

4. No linkage was detected between theTrflocus and sex, the agouti locus or the haemoglobin locus.

5. The possible molecular basis of the action of the transferrin alleles in the mouse, and the widespread distribution in mammals of polymorphism involving the transferrins, are discussed.