bluuebunny/crossref_metadata_2025 huggingface dataset:
Extending the shelf‐life of bananas with 1‐methylcyclopropene and a chitosan‐based edible coating
Authors: Baez‐Sañudo Manuel , Siller‐Cepeda Jorge , Muy‐Rangel Dolores , Heredia J Basilio
Published: August 2009

BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf‐life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1‐methylcyclopropene (SmartFreshSM, 1‐MCP) and a chitosan‐based edible coating (FreshSeal®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated.

RESULTS: After 3 days, control and EC‐treated fruits were completely yellow (°Hue = 90), while 1‐MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1‐MCP) reached a Hue value of 90. Firmer fruits were observed with 1‐MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1‐MCP either alone or combined. Sensory results showed no adverse effects by using the 1‐MCP or the edible coating.

CONCLUSION: The combined treatment of EC + 1‐MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry
Enantioseparation of dansyl amino acids by ligand‐exchange capillary electrophoresis with zinc(II)‐L‐phenylalaninamide complex
Authors: Qi Li , Yang Gengliang
Published: August 2009

A novel method of chiral ligand‐exchange CE was developed with L‐amino acylamides as a chiral ligand and zinc(II) as a central ion. It has been demonstrated that these chiral complexes, such as Zn(II)‐L‐alaninamide, Zn(II)‐L‐prolinamide, and Zn(II)‐L‐phenylalaninamide, are suitable for use as chiral selectors for the enantioseparation of either individual pair of or mixed dansyl amino acids. The optimal separation running buffer consisted of 5 mM ammonium acetate, 100 mM boric acid, 4 mM ZnSO4·7 H2O, and 8 mM L‐amino acylamides at pH 8.2. The experiments showed that apart from the effect of the concentration of the complexes on the resolution and the migration time, the buffer pH also had a sharp influence on resolution. The employed chiral ligands exhibited different enantioselectivities and enantiomer migration orders. D‐Amino acids migrate faster than L‐amino acids when Zn(II)‐L‐alaninamide and Zn(II)‐L‐phenylalaninamide are used as chiral selectors, but it was observed that the migration order is reversed when Zn(II)‐L‐prolinamide is used as the chiral selector. Furthermore, the amount of dansylated amino acids is found to be highly dependent on the labeling temperature.
Formation of Two Kinds of Hexagonally Arranged Structures in ABC Triblock Copolymer Thin Films Induced by a Strongly Selective Solvent Vapor
Authors: Luo Chunxia , Huang Weihuan , Han Yanchun
Published: August 2009

An order–order transition (OOT) in the sequence of a hexagonally arranged core–shell cylinder to a double‐hexagonally arranged dot in polystyrene‐block‐poly(butadiene)‐block‐poly(2‐vinylpyridine) (SBV) triblock copolymer thin films is reported to be induced upon exposure to a solvent vapor that is strongly selective for the two end blocks. These two kinds of hexagonally arranged structures could form when the film thickness is 44, 123, and 223 nm. When the film thickness is decreased to 13 nm, the ordered structure is absent. The sizes of the core–shell cylinder structures formed with the same annealing time in films of different thickness are compared to address the effects of film thickness on the phase structure. The mechanism is analyzed from the total surface area of the blocks and the effective interaction parameter in the solvent vapor.

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Complementary and alternative medicine use in Gilles de la Tourette syndrome
Authors: Kompoliti Katie , Fan Wenqin , Leurgans Sue
Published: August 2009

The aim of this study was to describe the use of complementary and alternative medicine (CAM) in patients with Tourette syndrome (TS) and explore associations with CAM use. In recent years CAM use has increased, but rates of CAM use in TS patients are not reported. Consecutive TS patients or their parent(s), seen in an academic movement disorder center, completed a questionnaire regarding their use of CAM. One hundred TS patients or parents completed the questionnaire, mean age 21.5 ± 13.5, 76 males, 87 Caucasians. Sixty four patients had used at least one CAM modality. CAM treatments used were prayer (28), vitamins (21), massage (19), dietary supplements (15), chiropractic manipulations (12), meditation (10), diet alterations (nine), yoga (nine), acupuncture (eight), hypnosis (seven), homeopathy (six), and EEG biofeedback (six). Fifty six percent of patients using CAM reported some improvement. Users paid out of pocket for 47% of treatments pursued, and 19% of these payers received partial reimbursement by third party payer. Users and non‐users did not differ in age, gender, race, income, educational level, general health, tic severity, medication use for TS, current satisfaction from medications or experience of side effects from medications. CAM use was associated with the presence of affective disorder (P = 0.004), but not with either ADHD or OCD. Among CAM users, 80% initiated CAM without informing their doctor. CAM is commonly used in children and adults with TS, and often without the neurologist's knowledge. Physicians should inquire about CAM to understand the spectrum of interventions that patients with TS use. © 2009 Movement Disorder Society
Molecular characterization and polyadenylation‐regulated expression of cyclin B1 and Cdc2 in porcine oocytes and early parthenotes
Authors: Zhang Ding‐Xiao , Cui Xiang‐Shun , Kim Nam‐Hyung
Published: August 2009

Meiotic maturation of mammalian oocytes is controlled by the maturation/M‐phase promotion factor (MPF), a complex of Cdc2 kinase and cyclin B protein. To better understand the molecular mechanism of oocyte maturation, we characterized porcine cyclin B1 and Cdc2 genes, both of which are widely expressed in pig tissues. We further analyzed their expression profiles during in vitro maturation of pig oocyte and early embryonic development at both the mRNA and protein level. Two isoforms of cyclin B1, comprising the same open reading frame but differing in 3′‐UTR length, were identified. Cyclin B1 transcripts was up‐regulated after 30 hr of maturation, while Cdc2 mRNA levels were unchanged during maturation except for a sharp decline at 44 hr. Cyclin B1 protein synthesis increased with oocyte maturation. Cdc2 protein expression was relatively low during 0–18 hr, followed by a higher level of expression up to 44 hr of maturation. Poly(A)‐test PCR clearly revealed that both cyclin B1 isoforms underwent cytoplasmic polyadenylation starting around 18–24 hr during maturation, while a substantial de‐adenylation and degradation of Cdc2 isoforms were observed in metaphase II oocytes and during embryo development after parthenogenetic activation. Porcine MII oocytes derived from small follicles (≤3 mm) and bad quality 2‐cell parthenotes showed lower developmental competence and lower levels of cyclin B1 protein, and Cdc2 mRNA or both gene mRNAs, respectively, compared to their control counterparts. These results suggested that cyclin B1 was regulated posttranscriptionally by cytoplasmic polyadenylation during porcine oocyte maturation. Further, the decreased expression of maternal cyclin B1 and Cdc2 at the mRNA or protein level in developmentally incompetent oocytes and embryos was responsible for, at least in part, a profound defect in further embryonic development. Mol. Reprod. Dev. 77: 38–50, 2010. © 2009 Wiley‐Liss, Inc.
Synthesis of high‐impact biodegradable multiblock copolymers comprising of poly(butylene succinate) and poly(1,2‐propylene succinate) with hexamethylene diisocyanate as chain extender
Authors: Zheng Liuchun , Li Chuncheng , Huang Weiguo , Huang Xi , Zhang Dong , Guan Guohu , Xiao Yaonan , Wang Dujing
Published: August 2009

Block copolymers demonstrate excellent thermal and mechanical properties superior to their corresponding random copolymers and homopolymers. However, it is difficult to synthesize block copolymers comprising of different polyester segments by copolycondensation due to the serious transesterification reaction. In this study, multiblock copolymers comprising of two different polyester segments, i.e. crystallizable poly(butylene succinate) (PBS) and amorphous poly(1,2‐propylene succinate) (PPSu), were synthesized by chain‐extension with hexamethylene diisocyanate (HDI). Amorphous PPSu segment was incorporated to improve the impact strength of PBS. The copolymers were characterized by GPC, laser light scattering (LLS), NMR, DSC, and mechanical testing. The results of 13C NMR spectra suggest that multiblock copolymers with regular sequential structure have been successfully synthesized. The data of DSC and mechanical testing indicate that block copolymers possess excellent thermal and mechanical properties with satisfactory tensile strength and extraordinary impact strength achieving upto 1900% of pure PBS. The influence of PPSu ratio and chain length of both the segments on the thermal and mechanical properties was investigated. The incorporation of an amorphous soft segment PPSu imparts high‐impact resistance to the copolymers without obviously decreasing the melting point (Tm). The favorable mechanical and thermal properties of the copolymers also depend on their regular sequential structure. At the same time, the introduction of amorphous PPSu segment enhances the enzymatic degradation rate of the multiblock copolymers. Copyright © 2009 John Wiley & Sons, Ltd.
Evaluating the processability of film blowing resins
Authors: Tiang Jen Shueng , Dealy John M.
Published: August 2009

A key factor that limits the production rate in film blowing is bubble instability. Although processing conditions play an important role, it is well known that some resins are more resistant to instabilities than others. It is clear that long‐chain branching enhances stability, but it is not currently possible to model the process with sufficient accuracy to establish a quantitative relationship between rheological properties and blown film processability. It would thus be useful to be able to compare the processabilities of film resins by means of a laboratory measurement. We compared two laboratory tests that may be helpful in evaluating the ability of a resin to resist instabilities in the film blowing process. One of these was a film resin tester designed to simulate some aspects of the film blowing process, and the other was an extensional rheometer. We used a set of polyethylene resins that had been used previously in an extensive study of blown film stability. The extensional rheometer clearly shows the superiority of low‐density polyethylene but is not able to distinguish among polymers of other types. The melt tester, on the other hand, is sensitive to differences among linear polymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Electrical conductivity and thermal properties of acrylonitrile‐butadiene‐styrene filled with multiwall carbon nanotubes
Authors: Wang Wen‐Yi , Luo Guo‐Hua , Wei Fei , Luo Jian
Published: August 2009

Composites of Acrylonitrile‐butadiene‐styrene (ABS) and multiwall carbon nanotubes (MWNTs) have been prepared via solution‐blending. The electrical conductivity of these composites is analyzed. The MWNT‐filled ABS shows percolation point of the electrical conductivity at low filler loadings (1–2 wt%). The micro‐structure of the composites is also analyzed by scanning electron microscopy showing that the nanotubes are dispersed quite homogeneously in the polymer‐matrix. The thermogravimetric analysis is used to study the thermal degradation of ABS/MWNTs composites in nitrogen. MWNTs tend to destabilize the ABS matrix in the 220–450°C degradation regions but improve the thermal stability in the 425–850°C regions. With further addition of MWNTs, the features of the destabilization in the 220–450°C degradation region did not change much but in the 425–850°C degradation process, the MWNTs reinforced stabilization and the quality of the char residue of amorphous carbon deposition was improved. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Properties of ultrahigh‐molecular‐weight polyethylene nanocomposite films containing different functionalized multiwalled carbon nanotubes
Authors: Ko Jeong‐Ho , Chang Jin‐Hae
Published: August 2009

We compared the thermomechanical properties, morphologies, gas permeabilities, and electrical conductivities of ultrahigh‐molecular‐weight polyethylene (UHMWPE) nanocomposite films containing two types of functionalized multiwalled carbon nanotubes (functionalized MWNTs). Both 2‐hydroxyethyl triphenyl phosphonium‐MWNT (Ph3P‐MWNT) and 1,1,1,3,3,3‐hexafluoro‐2‐phenyl‐2‐propanol‐MWNT (CF3‐MWNT) were used as reinforcing fillers in the fabrication of UHMWPE hybrid films. UHMWPE nanocomposites with various functionalized MWNT contents were solution‐cast to produce the films. The thermomechanical properties and morphologies of the UHMWPE hybrid films were then characterized using differential scanning calorimetry, thermogravimetric analysis, electron microscopy, and mechanical tensile analysis. Transmission electron microscopy studies showed that some of the MWNT particles were dispersed homogeneously within the polymer matrix (on the nanoscale), whereas others were agglomerated. We also found that the addition of only a small amount of functionalized MWNTs was sufficient to improve the thermomechanical properties and the gas barrier of the UHMWPE hybrid films. Even, those hybrid films with low functionalized MWNT contents (i.e., <1 wt%) were found to exhibit much better thermomechanical properties than the pure UHMWPE films. On the other hand, the values of the electrical conductivity remained constant, regardless of the amount of functionalized MWNTs. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Polymer electrolyte membranes for high‐temperature fuel cells based on aromatic polyethers bearing pyridine units
Authors: Kallitsis Joannis K , Geormezi Maria , Neophytides Stylianos G
Published: August 2009

This review is focused on the design and synthesis of new high‐temperature polymer electrolytes based on aromatic polyethers bearing polar pyridine moieties in the main chain. Such materials are designed to be used in polymer electrolyte fuel cells operating at temperatures higher than 100 °C. New monomers and polymers have been synthesized and characterized within this field in respect of their suitability for this specific application. Copolymers with optimized structures in order to combine excellent film‐forming properties with high mechanical, thermal and oxidative stability and controlled acid uptake have been synthesized which, after doping with phosphoric acid, result in ionically conducting membranes. Such materials have been studied in respect of their conductivity under various conditions and used for the construction of membrane‐electrode assemblies (MEAs) which are used for fuel cells operating at temperatures up to 180 °C. New and improved, in terms of oxidative stability and mechanical properties in the doped state, polymeric membranes have been synthesized and used effectively for MEA construction and single‐cell testing. Copyright © 2009 Society of Chemical Industry
Synthesis of fluoro‐substituted silole‐containing conjugated materials
Authors: Horst Sven , Evans Nicholas R. , Bronstein Hugo A. , Williams Charlotte K.
Published: August 2009

2,5‐Dihydroxyboryl‐1,1‐dimethyl‐3,4‐bis(3‐fluorophenyl)‐silole (2a) was prepared in 40% overall yield by reaction between 3‐fluorophenyl‐acetylene and dichlorodimethylsilane to yield bis[2(3‐fluorophenyl)ethynyl]dimethylsilane (1a), which subsequently undergoes a reductive cyclization reaction using an excess of lithium naphthalenide. The fluoro substituted silole was applied as a co‐monomer in the Suzuki polycondensation reaction with 2,7‐dibromo‐9,9‐dioctyl‐fluorene. An oligomer (3a) with a degree of polymerization of 6 was prepared and compared with an oligomer without fluoro substitution on the silole (3b), with a degree of polymerization of 4. The new oligomers were spin coated onto glass slides and showed weak green photoluminescence (PL) in the solid state. Cyclic voltammetry, visible absorption spectroscopy, and density functional theory calculations showed that the fluoro substituents were sufficiently electron withdrawing to lower both the highest occupied molecular orbital and the lowest unoccupied molecular orbital in the oligomer. Two further alternating co‐oligomers were prepared from 2,5‐dihydroxyboryl‐1,1‐dimethyl‐3,4‐bis(phenyl)‐silole (2b) and 1,3‐dibromo‐5‐fluoro‐benzene (4a) or 1,3‐dibromobenzene (4b). These oligomers both had degrees of polymerization of 8 and showed green PL in the solid state. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5116–5125, 2009
Simplified synthesis of spiro‐bridged ladder‐type poly(p‐phenylene)
Authors: Wang Baoling , Forster Michael , Preis Eduard , Wang Huan , Ma Yuguang , Scherf Ullrich
Published: August 2009

In this study, a simplified route to synthesize soluble, spiro‐bridged ladder‐type poly(p‐phenylene)s (spiro‐LPPP) was developed. The new, simplified synthesis route for spiro‐LPPP involves two reaction steps: a single‐stranded precursor polymer containing diaryloylbenzene building blocks was obtained by the Suzuki reaction, followed by a subsequent twofold cyclization cascade using methanesulfonic acid to form the target spiro‐LPPP. Spiro‐LPPP shows a well‐defined chemical structure, high molecular weight (Mn of 17,500 g/mol with a polydispersity index of 2.0), excellent thermal stability (5% weight loss at 370 °C), and good solubility in common organic solvents. Spiro‐LPPP emits blue light (λmax,em = 455 nm) with the high solution PL quantum yield (94%). The spectral properties of spiro‐LPPP in the solid state are very similar to the solution properties, thus indicating a low degree of intermolecular aggregation. After annealing a thin film of spiro‐LPPP to 120 °C in air for 3 to 24 h, its emission spectrum is unchanged, reflecting excellent thermooxidative stability. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5137–5143, 2009
Humoral immune response against 38‐ and 16‐kDa mycobacterial antigens in childhood tuberculosis
Authors: Senol Gunes , Ecevit Cigdem , Öztürk Aysel
Published: August 2009

Several enzyme‐linked immunosorbent assays (ELISAs) based on mycobacterial antigens have been tried for the rapid diagnosis of tuberculosis (TB). In this study, the value of the 16 and 38‐kDa mycobacterial antigens in the diagnosis of TB was investigated in pediatric patients in Izmir, Turkey in whom they were found using clinical and/or bacteriological methods. A commercial ELISA kit was used for measuring IgG against 38 and 16‐kDa recombinant antigens. The humoral immune response was analyzed in a group of 32 TB patients (24 pulmonary, 3 lymphadenitis and 2 pleuritis, 2 meningitis and a disseminated TB) and in control groups consisting of 20 healthy children and 20 pulmonary diseases other than TB cases. The sensitivity, specificity, positive predictive value, and the negative predictive value of the test were found to be 25%, 90%, 66.7%, and 60%, respectively, in the TB cases. The ELISA test shows very good specificity, but low level of sensitivity and negative predict value. It was thought that it might be used in combination with other methods to increase diagnostic accuracy, especially for culture‐negative TB pediatric cases, which are difficult to diagnose. Pediatr Pulmonol. 2009; 44:839–844. © 2009 Wiley‐Liss, Inc.
Microstructural, electrical, magnetic and spectroscopic properties of PbOSb2O3As2O3:MnO glass ceramics
Authors: Padmanabham A. , Satyanarayana T. , Gandhi Y. , Veeraiah N.
Published: August 2009

PbOSb2O3As2O3 glasses mixed with different concentrations of MnO (ranging from 0 to 5.0 mol%) were crystallized. The samples were characterized by X‐ray diffraction, scanning electron microscopy and differential thermal analysis techniques. Dielectric properties over a range of frequency and temperature, optical absorption, fluorescence IR, ESR and magnetic susceptibility at room temperature have been studied. The X‐ray diffraction studies have revealed the presence of Pb5Sb2O8, PbSb2O6, SbAsO4, Mn2Sb2O7, Mn3Sb2O6, Mn2O3, MnAsO4 and Pb5Sb4O11 crystalline phases in these samples. The DTA studies have indicated the spreading of the crystallization from inside to the surface of the samples as the concentration of the crystallizing agent is increased. The IR studies have pointed out the existence of conventional AsO3 and SbO3 structural units in the glass ceramic samples. These studies have further indicated the decreasing concentration of symmetrical structural vibrational groups with increase in the concentration of MnO. The results of various studies viz., also been reported. The results of optical absorption, ESR, luminescence and magnetic susceptibility studies have been analysed in the light of different oxidation states and environment of manganese ions in the glass ceramic network.
X‐ray photoelectron spectroscopy study of sodium–copper–germanate glasses
Authors: Mekki A. , Khattak G. D.
Published: August 2009

Sodium germanate glasses containing copper oxide with the nominal composition (0.70 − x) GeO20.30Na2OxCuO, (x in the range 0–0.15 mol%), were prepared and their structure as well as the valence state of the copper ions have been investigated by X‐ray photoelectron spectroscopy (XPS). The absence of “shake up” satellite peak in the Cu 2p spectra for glasses with x = 0.05 and 0.15 suggests the presence of copper in the Cu+ state for these glasses while the presence of both oxidation states (Cu+ and Cu2+) in the glass with x = 0.10 has been concluded from the presence of satellite structure of the Cu 2p core level spectra as well as the observation of asymmetry in the Cu 2p spectra. A deconvolution procedure has been undertaken to determine quantitatively the Cu2+/Cutotal ratio for x = 0.10 glass composition. The non‐bridging oxygen content, obtained from the deconvolution of the O 1s core level spectra, increases with increasing copper oxide content indicating that copper acts as a network modifier. The Ge 3d core level spectra show asymmetry and were fitted with two contributions, one due to Ge atoms in Ge (IV) coordination and the other due to Na 2p core level spectra which were overlapping with the Ge 3d peaks.
Fabrication study of AlN solar‐blind (<280 nm) MSM photodetectors grown by low‐temperature deposition
Authors: Chen Meei‐Ru , Chang S. H. , Chen Tzu Chieh , Hsu Chih‐Hsiang , Kao H. L. , Chyi Jen‐Inn
Published: August 2009

AlN, an important semiconductor with the widest band gap among III‐nitrides, was employed to construct solar blind metal–semiconductor–metal photodetectors (MSM‐PDs). MSM‐PDs were fabricated on AlN epitaxial thin films deposited on GaN/sapphire using a helicon sputtering system at a low temperature of 300 °C. The dark current of the device is as low as 200 fA at 20 V and the photocurrent illuminated by a D2 lamp increases more than two orders of magnitude. The photocurrent increases almost linearly with the incident optical power at the wavelength of 200 nm. The results show that the low temperature grown AlN MSM device is suitable for the application of deep UV detection.
Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc
Authors: Aristov V. Yu. , Molodtsova O. V. , Ossipyan Yu. A. , Doyle B. P. , Nannarone S. , Knupfer M.
Published: August 2009

The chemistry and electronic properties of the interfaces formed between the ferromagnetic metal (Fe) and the model organic semiconductor copper phthalocyanine are investigated in ultra‐high vacuum conditions for the case of metal deposition onto the organic molecular thin film. The studies were performed by means of core‐level and valence‐band high‐resolution photoemission electron spectroscopy (PES) as well as near‐edge X‐ray absorption fine structure using synchrotron radiation. Metal overlayer formation on the top of the organic semiconductor was observed without substantial penetration of deposited metal species into the organic film. At the thin interface layer the ferromagnetic metal shows strong chemical interaction with the nitrogen and carbon of the organic films. Moreover, our results infer that, as a consequence of Fe deposition onto CuPc, central copper atoms of the organic molecules at the interface are reduced from Cu(II) to Cu(I), while Fe atoms are oxidized and/or the ferromagnetic metal replaces this central Cu atom. Further optimization of such an interface is thus required to allow and/or facilitate the injection of spin‐polarized carriers into organic semiconductors.
Vertically aligned diamond nanowires: Fabrication, characterization, and application for DNA sensing
Authors: Yang Nianjun , Uetsuka Hiroshi , Williams Oliver A. , Osawa Eiji , Tokuda Norio , Nebel Christoph E.
Published: August 2009

In this review, we introduce a novel procedure to fabricate vertically aligned diamond nanowires with controlled geometrical properties like length and distance between wires by use of nanodiamond particles as a hard mask and by use of reactive ion etching. We summarize the characterizations of nanowires by atomic force microscopy and scanning tunneling microscopy as well as electrochemical techniques. In the last section, we show biofunctionalization of nucleic acid molecules on diamond nanowires using electrochemically bond nitrophenyl molecules as linker for deoxyribonucleic acid (DNA) sensing. The tip biofunctionalization and performance of as‐prepared DNA sensors are discussed in detail.
Doping‐induced changes in the valence band edge structure of homoepitaxial B‐doped diamond films below Mott's critical density
Authors: Takeuchi D. , Ogura M. , Tokuda N. , Okushi H. , Yamasaki S.
Published: August 2009

Heavily boron‐doped p‐type diamond is a key material for developing diamond‐based applications in various fields. We obtain information about changes in the valence band edge of homoepitaxial boron‐doped diamond films around and below Mott's critical density for a metal–non‐metal transition. For a boron concentration of about 2–3 × 1020 cm−3, where this transition is expected to occur, a metal‐like behaviour is observed at room temperature (RT) with the Fermi‐level lying 0.1 eV above the valence band edge. For a boron concentration about 4 × 1019 cm−3, which is well below the critical density, the valence band edge is quite different from that of lightly doped samples. It is proposed as an explanation for these experimental differences that the excited‐states of acceptors overlap.
Nickel doping of nitrogen enriched CVD‐diamond for the production of single photon emitters
Authors: Wolfer M. , Kriele A. , Williams O. A. , Obloh H. , Leancu C.‐C. , Nebel C. E.
Published: August 2009

Chemical vapour deposition has been utilised for the fabrication of nickel–nitrogen defects in diamond. By introducing nickel, as well as nitrogen into the process gas, this approach offers the advantage, that a direct formation of nickel–nitrogen centres on the growing surface is possible. This could therefore make postannealing steps superfluous. Nanocrystalline diamond films, as well as single crystal layers were grown under addition of nickel and nitrogen using different doping sources, namely: gaseous nickelocene, nickel powder and nickel wire. The amount of nickel present in the gas phase was characterised by optical emission spectroscopy (OES). In order to investigate the presence of nickel or nickel–nitrogen‐related defects, photoluminescence (PL) measurements at different temperatures have been applied. A strong fluorescence in the range between 800 and 900 nm, accompanied by a peak at around 817 nm, as well as a narrow peak at 788 nm has been observed at cryogenic temperatures (10 K). The peak at 788 nm indicates the presence of nickel and nickel–nitrogen‐related complexes in our samples. PL measurements at higher temperatures reveal, an initially rising intensity of a broad emission band at temperatures up to 200 K, while the emission is quenched at 300 K.
Measurement and analysis of ‘small’ packages in next‐day air shipments
Authors: Singh S. P. , Singh J. , Chiang K. C. , Saha K.
Published: August 2009

Packaged goods are shipped globally using various means of transportation. Over the past two decades, there has been a continuous increase in studies that measure and analyse dynamic events that occur to packages during transportation and handling. These data offer useful information to design and test packages, and provide protection from potential hazards like drops and impacts. However, none of the past studies are directed towards single packages regarded as ‘smalls’. ‘Smalls’ or small‐package product systems are defined as those with volume of less than 0.013 m3, a longest dimension of 0.356 m and a weight of 4.54 kg or less. Packages that qualify for these specifications are often mixed together in a large carrying bag and handled with other single parcel shipments. This study measured and analysed the effect of moving this category of single packages through expedited shipments in the USA. The results showed that these packages experienced as many as 27 events comprising of drops or tosses in a one‐way shipment, and a maximum of 5.01 m of near‐zero G travel distance representing long ‘tosses’. Copyright © 2009 John Wiley & Sons, Ltd.
Synoptic variability of the monsoon flux over West Africa prior to the onset
Authors: Couvreux F. , Guichard F. , Bock O. , Campistron B. , Lafore J.‐P. , Redelsperger J.‐L.
Published: August 2009

This study investigates the synoptic variability of the monsoon flux during the establishment of the West African monsoon using observations and ECMWF analyses. It highlights variability at a 3–5‐day time scale, characterized by successive northward excursions of the monsoon flux. Their characteristics and climatology prior to the monsoon onset are presented. These penetrations follow a maximum of intensity of the heat‐low (extension and minimum of pressure) and are concomitant with an acceleration of the low‐level meridional wind. Some penetrations are stationary whereas others propagate westward simultaneously with African easterly waves. Both types are investigated in more detail by case‐studies. This enables us to distinguish the boundary‐layer mechanisms involved in such penetrations. A similar conceptual model holds for both. It is argued that the heat‐low dynamics is a major driver of these synoptic penetrations, pointing to the predominantly continental nature of this phenomenon. In turn, the heat‐low can be partitioned by the penetrations. Horizontal advection is the main process that eventually accounts for these surges; nevertheless, turbulent mixing also plays a significant role by vertically redistributing moisture, and in more subtle ways by its contribution to the shaping of the low‐level synoptic environment within which the surges take place. Copyright © 2009 Royal Meteorological Society
A stochastic model for microtubule dynamicity involving mixtures of tubulin isotypes
Authors: Rezania Vahid , Tuszynski Jack A.
Published: August 2009

Experimental studies on the dynamicity of microtubules in a mixed αβII/αβIII tubulin solution show a nonlinear dependence with respect to the relative αβII/αβIII concentration. In this article, a physical model explaining this phenomenon in terms of tubulin dimers' affinity is introduced. We argue that lower affinities of tubulin dimers belonging to the same isotype than those that represent different isotypes indicate hitherto unsuspected influences of tubulin dimers on each other within a microtubule. We further show that similar influences between GTP‐GTP, GTP‐GDP, and GDP‐GDP tubulin dimers could also play a major role in the structure of the microtubule tip and hence in determining the microtubule's growth and/or shortening phases. These results can guide a future atomistic‐level model development. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
The role of gold adatoms in self‐assembled monolayers of thiol on Au(111)
Authors: Torres Edmanuel , Biedermann P.Ulrich , Blumenau Alexander T.
Published: August 2009

The role of Au adatoms in high‐density alkanethiol self‐assembled monolayers (SAMs) has been investigated. Surface reconstructions in ethylthiol (ET) SAMs due to gold adatoms have been studied using DFT calculations. Relative energies are compared based on binding and surface energies calculated for different lattices using the same unit cell. We have found a structure with two ET‐Au‐ET adatom moieties binding on top of surface gold atoms as the most stable structure. Our model is consistent with the structural parameters obtained from experiments. In particular, the simulated STM image displays the characteristic zig‐zag pattern. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Matrix suppression and analyte suppression effects of quaternary ammonium salts in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry: an investigation of suppression mechanism
Authors: Lou Xianwen , van Dongen Joost L. J. , Vekemans Jef A. J. M. , Meijer E. W.
Published: August 2009

In the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI TOF MS) analysis of some quaternary ammonium salts (QASs), very clean spectra of the quaternary ammonium ions were recorded with a strong matrix suppression effect (MSE). The QASs also showed a considerable analyte suppression effect (ASE). It was demonstrated that the MSE and ASE of the QASs can be explained well by the cluster ionization model. According to this model, MALDI ions are formed from charged matrix/analyte clusters. Various analyte ions and matrix ions might coexist in the cluster, and they will compete for the limited number of net charges available. If enough quaternary ammonium ions are present in the cluster, they will take away the net charges, thus resulting in the MSE and ASE. Our results also suggest that ‘the cluster ionization model’ is not in conflict with ‘the theory of ionization via secondary gas‐phase reactions’. The initial MALDI ions produced from charged matrix/analyte clusters will collide with other molecules or ions in the MALDI plume. Depending on the properties of the initial ions and the composition of the MALDI plume, secondary gas‐phase reactions might result from these collisions. The final ions observed are the combined results of ‘cluster ionization’ and ‘ionization via secondary gas‐phase reactions’. Copyright © 2009 John Wiley & Sons, Ltd.
Gas chromatography/time‐of‐flight mass spectrometry of triacetone triperoxide based on femtosecond laser ionization
Authors: Yamaguchi Satoshi , Uchimura Tomohiro , Imasaka Tomoko , Imasaka Totaro
Published: August 2009

Triacetone triperoxide (TATP), which is used as an explosive in acts of terrorism, was measured by means of gas chromatography/multiphoton ionization/time‐of‐flight mass spectrometry using a deep‐ultraviolet (deep‐UV) femtosecond laser as an ionization source. The fragmentation process was investigated by changing the intensity of the laser at the center axis of a molecular beam. A molecular ion was observed using a femtosecond laser, and the ratio of the intensities of the molecular and fragment ions decreased as the intensity of the laser increased. These results suggest that TATP can be efficiently ionized using a deep‐UV, ultrashort optical pulse. Furthermore, fragmentation was accelerated by excess energy supplied through higher‐order multiphoton processes under a strong radiation field. The detection limits obtained using the molecular ion and two dominant fragment ions, C2H3O+ and CH, were determined to be 670, 83 and 150 pg, respectively. Copyright © 2009 John Wiley & Sons, Ltd.
Partial atrioventricular septal defect in the fetus: diagnostic features and associations in a multicenter series of 30 cases
Authors: Paladini D. , Volpe P. , Sglavo G. , Russo M. G. , De Robertis V. , Penner I. , Nappi C.
Published: August 2009

Objective

To assess the anatomical features and the associations of partial atrioventricular septal defect (pAVSD) in the fetus.

Methods

This was a retrospective multicenter study of 30 cases of confirmed pAVSD seen since 1996 at two referral centers. The following variables were available for analysis in all cases: indications for fetal echocardiography, diagnostic features, associated cardiac, extracardiac and chromosomal anomalies and fetoneonatal outcome. At fetal echocardiography, the echocardiographic features deemed indicative of pAVSD were: 1) ostium primum atrial septal defect and 2) loss of the normal offset appearance of the atrioventricular valves.

Results

Eighteen of the 30 (60%) cases were diagnosed before 24 weeks of gestation and 12 were diagnosed later. Suspicion of congenital heart disease and known aneuploidy (trisomy 21) accounted for 60% of the referral indications. The two anatomical landmarks deemed indicative of pAVSD were detected in all cases at echocardiography. Twelve cases were isolated (one with increased nuchal transluceny at the 12‐week scan, one with polyhydramnios, one with fetal growth restriction) including four that were detected on routine ultrasound examination by the authors. Additional cardiac anomalies were present in five (17%) cases, four of which involved aortic coarctation. There were associated chromosomal anomalies in 13 (43%); however, excluding the six cases referred because of known Down syndrome, the adjusted association rate with aneuploidy was 29.2% (7/24). Extracardiac anomalies, including non‐chromosomal syndromes, were present in 10 cases (33.3%). Regarding fetoneonatal outcome, there were 13 terminations of pregnancy, one early neonatal death and 16 survivors, including four with mild to severe neurodevelopmental delay due to associated syndromic conditions.

Conclusions

We describe the key echocardiographic features of pAVSD in the fetus. In addition, we have confirmed that the association with trisomy 21 holds also for pAVSD, though to a lesser extent, with a 12.5% association rate in this series. In the fetus, pAVSD seems to be associated with a high rate of chromosomal/non‐chromosomal syndromic conditions, including skeletal dysplasias. Inutero, aortic coarctation represents the most frequently associated cardiac lesion (13.3%). Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Transvaginal ultrasonography and magnetic resonance imaging for assessment of presence, size and extent of invasive cervical cancer
Authors: Testa A. C. , Ludovisi M. , Manfredi R. , Zannoni G. , Gui B. , Basso D. , Di Legge A. , Licameli A. , Di Bidino R. , Scambia G. , Ferrandina G.
Published: August 2009

Objectives

To prospectively assess the diagnostic performance of transvaginal ultrasound and magnetic resonance imaging (MRI), using histology as the gold standard, with regard to the presence, size, and extent of invasive cervical cancers and the detection of metastatic lymph nodes.

Methods

This was a prospective study designed to examine patients with invasive cervical cancer by means of ultrasonography and MRI within 1 week before surgery. We included patients with early cervical cancer planned for primary surgery and patients with locally advanced cervical cancer planned for surgery after neoadjuvant treatment.

Results

An invasive cervical cancer tumor was confirmed in the 33 patients triaged for primary surgery. A residual tumor mass was documented in 27 out of 35 patients (77%) who underwent surgery after neoadjuvant treatment, with no residual tumor in eight (23%) cases. Transvaginal ultrasound and MRI examinations showed the presence of the tumor mass in 56/60 (93%) and in 53/60 (88%) cases, respectively. Ultrasound and MRI detected the depth of stromal invasion to be greater than two‐thirds with a sensitivity of 100% (16/16) and 94% (15/16) (P = 1) and a false‐positive rate of 25% (13/52) and 15% (8/52) (P = 0.58), respectively. Both ultrasound and MRI provided low sensitivities (3/5, 60% and 2/5, 40% respectively, P = 1) and the same false‐positive rate (7/63, 11%) for the presence of parametrial infiltration. One of the 11 patients with metastatic lymph nodes was detected at ultrasound examination (sensitivity 9%) with no false‐positive cases, while MRI correctly identified three positive cases (sensitivity 27%, 3/11) with two false‐positive cases (false positive rate 4%, 2/55).

Conclusions

Ultrasound and MRI had similar sensitivity and specificity with regard to the parameters investigated. Ultrasound has the advantages over MRI of low cost, widespread availability and of being a relatively quick procedure. Ultrasound should be considered as a suitable diagnostic method in the preoperative work‐up of cervical cancer. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Increase in cytosolic calcium maintains plasma membrane integrity through the formation of microtubule ring structure in apoptotic cervical cancer cells induced by trichosanthin
Authors: Wang Ping , Xu Shujun , Zhao Kai , Xiao Bingxiu , Guo Junming
Published: August 2009

This study investigates the role of dysregulated cytosolic free calcium ([Ca2+]c) homeostasis on microtubule (MT) ring structure in apoptotic cervical cancer (HeLa) cells induced by trichosanthin (TCS), a type I ribosome inactivating protein (RIP). The TCS‐induced decrease in cell viability was significantly enhanced in combination with the specific calcium chelator, EGTA‐AM. Sequestration of [Ca2+]c markedly disrupted the special MT ring structure. Furthermore, TCS tended to increase LDH release, whereas no significant differences were observed until 48 h of the treatment. In contrast, combined addition of EGTA‐AM or colchicine (an inhibitor of tubulin polymerization) significantly reinforced LDH release. The data suggest that TCS‐elevated [Ca2+]c maintains plasma membrane integrity via the formation of the MT ring structure in apoptotic HeLa cells.
Mesenchymal stem cells regulate the proliferation and differentiation of neural stem cells through Notch signaling
Authors: Wang Yang , Tu Wei , Lou Yuanlei , Xie An , Lai Xianliang , Guo Fei , Deng Zhifeng
Published: August 2009

The effects of mesenchymal stem cells (MSCs) on proliferation and cell fate determination of neural stem cells (NSCs) have been investigated. NSCs were co‐cultured with MSCs or NIH3T3 cells using an in vitro transwell system. After 4 days, immunofluorescence staining showed that the number of cells positive for the cell proliferation antigen, ki‐67, in neurospheres in MSCs was greater than in NIH3T3 cells. In some experiments, the top‐layers of MSCs and NIH3T3 cells were removed to induce NSCs differentiation. Seven days after initiating differentiation, the levels of the neuronal marker, NSE, were higher in NSCs in MSCs co‐culture group, and those of glial fibrillary acidic protein (GFAP) were lower, compared with NIH3T3 cells co‐culture group. These were confirmed by immunofluorescence. The role of the Notch signaling pathway analyzed with the specific inhibitor, DAPT, and by examining the expression of Notch‐related genes using RT‐PCR showed that after co‐culturing with MSCs for 24 h, NSCs expressed much higher levels of ki‐67, Notch1, and Hes1 than did NSCs co‐cultured with NIH3T3 cells. Treatment with DAPT decreased ki‐67, Notch1 and Hes1 expression in NCSs, and increased Mash1 expression. The data indicate that the interactions between MSCs and NSCs promote NSCs proliferation and are involved in specifying neuronal fate, mediated in part by Notch signaling.
Human impacts, climate change, and aquatic ecosystem response during the past 2000 yr at Lake Wandakara, Uganda
Authors: Russell James M. , McCoy S.J. , Verschuren D. , Bessems I. , Huang Y.
Published: August 2009

Analyses of carbon and hydrogen isotope ratios of terrestrial leaf waxes and the carbon and nitrogen abundance, ratio, and isotopic composition of bulk sediments from Lake Wandakara, a crater lake in western Uganda, East Africa, document human and climatic controls on the aquatic system and on the surrounding terrestrial vegetation during the past two millennia. Our data indicate that Wandakara was a relatively stable, productive lake surrounded by C3 vegetation from AD 70 to 1000. Abrupt changes in the δ13C of terrestrial leaf waxes indicate a series of abrupt shifts in the relative abundance of C3 and C4 vegetation caused by a combination of climate change and human activities around Wandakara beginning at AD 1000. Abrupt shifts in bulk sediment organic geochemistry, particularly C/N ratios and δ15N, indicate that human activities at this time caused permanent changes in the limnology of Lake Wandakara, including eutrophication. Our results suggest that the biogeochemistry of Lake Wandakara was more sensitive to shifting human impacts than to climate variations during the past millennium, highlighting the importance of understanding the intensity of pre-colonial human impacts on Africa's aquatic ecosystems.
Professor George Coedès, 1866–1969: A Memoir
Authors: Osborne Milton
Published: August 2009

The world of Southeast Asian scholarship has suffered an immeasurable loss with the death in October 1969 of Professor George Coedès, the undisputed doyen of those who have studied the early history of the region. In a lifetime of scholarly activity, beginning with the publication of his first article on the early history of Cambodia in 1904, Professor Coedès prepared a rich heritage for those who seek to understand the intricacies of the history and culture of the Indianised states of Southeast Asia.
Burmese and Malaysian Student Politics: A Preliminary Comparative Inquiry
Authors: Silverstein Josef
Published: August 2009

“Malaysia needs this kind of spirit.” With these words, the Prime Minister of Malaysia, Tunku Abdul Rahman, responded to a student demonstration supporting the nation against the 1968 territorial claims to Sabah put forth by the Philippines. Although he toned down his enthusiasm somewhat when later he learned that the same students had forced their way into the Philippine Embassy compound and had torn down its flag prior to their demonstration in front of his residence, there is no denying that this was another example of political change in Malaysia which is causing its leaders to come to grips with a comparatively new phenomena, students as participants in the political process.
Japan and Philippine Beer: The 1930s
Authors: Goodman Grant K.
Published: August 2009

During the 1930s Japanese business interests increasingly believed that if and when free trade or preferential trade between the United States and the Philippines were to be terminated Japan would necessarily profit by taking over a greater share of the Philippine market. Such anticipation was particularly stimulated after the passage of the Tydings-McDuffie Act and the establishment on November 15, 1935 of the Philippine Commonwealth which was to be the transitional form of government until full independence was granted on July 4, 1946. Thus the pace of Japanese commercial activity in the Islands accelerated significantly, and Japan's economic stake expanded accordingly. The skills, the business acumen and the unstinting diligence of the Japanese all served to provide them with financial rewards from the Philippine economy. Aggressive tactics, superior organization and sufficient capital also sustained and enhanced Japanese commercial success. All of these factors were evident in the chronology of the development of a Japanese stake in the brewing of Philippine beer.