bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacologic inhibition of platelet vWF-GPIbα interaction prevents coronary artery thrombosis
Authors: Swillo Robert , Morgan Gwen , Leik Courtney , Brooks Jonathan , Shaw Gray , Schaub Robert , Crandall David , Vlasuk George , Hennan James
Published: February 2006

Under high shear arterial blood flow von Willebrand Factor (vWF) binds the platelet receptor glycoprotein (GP) Ibα, leading to platelet adhesion, activation and thrombosis. Blockade of vWF-GPIbα interactions by GPG-290 was investigated in a canine model of coronary artery thrombosis alone and in combination with clopidogrel. GPG-290 (100 µg/kg, n=6; 500 µg/kg, n=6) prolonged time to thrombotic occlusion (TTO) to 105±34 and 156±23 (p<0.05) min, respectively compared to the saline treated control group (32±6min, n=6). Patency of the injured vessel was sustained in 1/6 (100µg/kg) and 3/6 vessels (500 µg/kg) 4 hours after injury, in contrast to 0/6 in the control group. There was an increase in bleeding after the 500 µg/kg dose, but only at the 1 hr time point. Clopidogrel was studied in two dosing regimens representing either a clinical pretreatment regimen (PTR) of 4.3 mg/kg on day –2 followed by 1.1 mg/kg daily for2 days prior to the procedure or pre-procedural loading dose regimen (LDR) of 4.3 mg/kg 3 hr pre-procedure. The PTR and LDR clopidogrel treatments prolonged TTO to 98.2±30.0 min and 136.1±39.5 min (p<0.05), and sustained patency in 1/6 and 4/8 vessels, respectively. However, template bleeding time in the LDR clopidogrel group was sustained higher than the control group. The combination of PTR clopidogrel and GPG-290 (100 µg/kg) prolonged TTO equivalent to LDR clopidogrel alone (141.4±35.1 min) and sustained patency in 3/7 dogs, without increased bleeding while LDR clopidogrel combined with 100 µg/kg GPG-290 prevented occlusion in 5/8 dogs and further prolonged TTO (173.5±32.6 min) but was associated with increased bleeding compared to control. GPG-290 is an antithrombotic agent that may be combined with lower doses of clopidogrel to yield similar antithrombotic efficacy as higher loading doses.
Warm-up exercise suppresses platelet-eosinophil/neutrophil aggregation and platelet-promoted release of eosinophil/neutrophil oxidant products enhanced by severe exercise in men
Authors: Yen Hsiang-Ling , Yang Chuen-Mao , Wang Jong-Shyan
Published: February 2006

Heterotypic platelet-eosinophil/neutrophil aggregation and subsequent release of eosinophil/neutrophil oxidant products contribute to pathogenesis of conditions such as asthma and inflammatory bowel diseases. This study investigates whether warmup exercise (WUE) affects platelet-eosinophil/neutrophil interaction mediated by high-intensity exercise (HIE). Twenty-three healthy sedentary men performed on three occasions light-intensity exercise (LIE, 40%VO2max for 40 min) and HIE (80%VO2max for 40 min) with and without WUE (40%VO2max for 20 min). Before and immediately after exercise, platelet-eosinophil and platelet-neutrophil aggregation (PEA and PNA), reactive oxygen species production of eosinophils and neutrophils (EROS and NROS) enhanced by platelets, and adhesion molecule expression on platelets, eosinophils, and neutrophils were measured. The results of this study demonstrated that HIE enhanced PEA, PNA, and platelet-induced EROS and NROS, was accompanied by increased expressions of Mac-1 on eosinophils and neutrophils and P-selectin on platelets at 5 dyne/cm2 of shear stress, 100 µg/ml lipopolysaccharide, and 1 µM N-formylmethionyl-leucyl-phenylalanine treatments, whereas the enhancement of HIE on platelet-eosinophil/neutrophil interaction was suppressed by WUE. Conversely, LIE significantly reduced PEA and PNA, suppressed platelet-induced EROS and NROS, and down-regulated eosinophil/neutrophil Mac-1 and platelet P-selectin expressions under various stimuli and shear flow conditions. Moreover, these effects were more pronounced in platelet interaction with eosinophils than with neutrophils. It is concluded that HIE enhances hetero-aggregation, adhesion molecules expressions, and subsequent oxidative bursts mediated by platelets and eosinophils/neutrophils, this effect diminishes after WUE. However, LIE minimizes the risk of thromboinflammation.
Antithrombotic effects of ximelagatran plus acetylsalicylic acid (ASA) and clopidogrel plus ASA in a human ex vivo arterial thrombosis model
Authors: Eriksson-Lepkowska Maria , Nyström Per , Eriksson Ulf , Sarich Troy , Badimon Juan , Kalies Inge , Elg Margareta , Bylock Anders , Wåhlander Karin
Published: February 2006

It was the objective of this study to compare the antithrombotic effects and bleeding profiles of the oral direct thrombin inhibitor ximelagatran, an anticoagulant, and the antiplatelet agent clopidogrel on top of steady-state acetylsalicylic acid (ASA) in a human arterial thrombosis model. Healthy male volunteers (n=62) received ASA (160 mg once daily),plus either clopidogrel for 6 days (loading dose 300 mg, then 75 mg once daily), or a single dose of ximelagatran (36 or 72 mg) on Day 6. Changes in total thrombus area (TTA) under low shear rate (LSR; 212 s-1) and high shear rate (HSR; 1690 s-1) conditions were measured, using the ex vivo Badimon perfusion chamber model pre-dose and 2 and 5 hours after dosing on Day 6, and capillary bleeding times (CBT) were determined. Ximelagatran plus ASA significantly reduced TTA under LSR and HSR, compared with ASA alone. Ximelagatran plus ASA reduced TTA more than clopidogrel plus ASA under LSR after2 hours (36 mg, P=0.0011; 72 mg, P<0.0001) and 5 hours (72 mg, P=0.0057), and under HSR after 2 and 5 hours (72 mg, P<0.05). Compared with ASA alone, CBT was markedly prolonged by clopidogrel plus ASA (ratio 6.4; P<0.0001) but only slightly by ximelagatran plus ASA (72 mg ximelagatran,ratio 1.4;P=0.0010).Both drug combinations were well tolerated. Oral ximelagatran plus ASA has a greater antithrombotic effect in this human ex vivo thrombosis model and a less prounounced prolongation of bleeding time than clopidogrel plus ASA.
The risk of recurrent venous thromboembolism in patients with unprovoked symptomatic deep vein thrombosis and asymptomatic pulmonary embolism
Authors: Díaz Gema , Marín Elena , Vidal Rafael , Sueiro Antonio , Yusen Roger , Jiménez David
Published: February 2006

Patients with a first episode of symptomatic pulmonary embolism (PE) havea higher risk of recurrent venous thromboembolism (VTE) than patients with a first episode of proximal lower extremity deep vein thrombosis (DVT). Patients with symptomatic DVT and silent PE may havea different risk of VTE recurrence than patients that have symptomatic DVT without PE. Therefore, it was the aim of this prospective cohort study to compare the risk of recurrent symptomaticVTE in patients with proximal lower extremity DVT and silent PE to the risk in patients that only have proximal lower extremity DVT. Ninty-one consecutive outpatients presenting to the emergency department of a university hospital subsequently hospitalised with a first episode of unprovoked symptomatic proximal lower extremity DVT, and without new pulmonary symptoms were included. Standard initial treatment consisted of intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin for 5–7 days, overlapped with oral vitamin-K antagonist therapy, with long-term oral vitamin-K antagonist therapy (goal INR 2.5 [2.0–3.0]). Study endpoints were: symptomatic recurrent DVT, new PE, and recurrent PE, evaluated by standard objective testing. At enrolment, 28 of 91 (31%) patients with DVT had silent PE. In the patients with DVT and silent PE, there were 3 VTE recurrences during 20 person-years of follow-up, while there were no VTE recurrences during 61 person-years of follow-up in the patients with isolated DVT. The Kaplan-Meier estimated VTE recurrence rate at 1 year after the diagnosis of DVT was 11% (95% CI: 2–28%) for patients with symptomatic DVT and silent PE, compared to 0% in patients with isolated symptomatic DVT (p = 0.0045). In patients with a first episode of unprovoked symptomatic acute proximal lower extremity DVT, the risk of recurrent VTE was significantly higher in those with silent PE compared to those without PE.
Anti-thrombotic effect of bivalirudin compared with eptifibatide and unfractionated heparin in diabetic patients
Authors: Lev Eli , Patel Rajnikant , Karim Azim , Kleiman Amanda , Badimon Juan , Kleiman Neal
Published: February 2006

Patients with diabetes who undergo percutaneous coronary intervention (PCI) are at high risk for thrombotic complications following the procedure. We sought to compare the anti-thrombotic effect of bivalirudin to that of eptifibatide plus unfractionated heparin in diabetic patients undergoing elective PCI. Thirty diabetic patients were randomized to receive during PCI either bivalirudin (bivalirudin group, n=15) or eptifibatide plus heparin (eptifibatide group, n=15) at standard dosing regimens. The drugs were continued for 20 minutes (bivalirudin) or 18 hours (eptifibatide) after PCI. Blood thrombogenicity was assessed using the Badimon ex vivo perfusion chamber. Each patient underwent two perfusion studies – at baseline (on aspirin and clopidogrel) and 15–20 minutes following PCI. Perfusion studies were performed at rheologic conditions of low and high shear rates (LSR, HSR). Porcine aortic tunica media served as the thrombogenic substrate. Aortic specimens were stained for total platelet-thrombus and fibrin deposition. Thrombus area was measured using computerized planimetry. There were no differences in clinical characteristics or baseline thrombus area between the two groups. Total platelet-thrombus area was reduced significantly in both groups, but the degree of reduction was lower in the bivalirudin group compared with the eptifibatide group (HSR: 69.5% vs. 89.3% reduction, respectively, P=0.04; LSR: 50.6% vs. 73.2%, P=0.03). Fibrin deposition was reduced in both groups by 47–49%. In conclusion, both bivalirudin and the combination of eptifibatide plus heparin, given to diabetic patients during PCI, achieved marked reductions in total thrombus formation and fibrin deposition. However, glycoprotein IIb/IIIa inhibition by eptifibatide causeda more pronounced reduction in thrombus formation.
Human endothelial cells synthesize protein Z, but not the protein Z dependent inhibitor
Authors: Denoyelle Christophe , Corbière Cécile , Litzler Pierre-Yves , Legrand Elisabeth , Vannier Jean-Pierre , Vasse Marc
Published: February 2006

Protein Z (PZ) is a vitamin K-dependent protein isolated from human plasma, and acts as a cofactor fora serpin, called protein Z-dependent protease inhibitor (ZPI).A prothrombotic phenotype has been reported in PZ deficient mice, and PZ deficiencies have been observed in patients with arterial thrombotic events. PZ was immunologically detected in the endothelium of atherosclerotic arteries, suggesting that endothelial cells could be involved in the production of PZ.In this study we analyzed the synthesis and release of PZ and ZPI by human umbilical vein endothelial cells (HUVEC), representative of the macrovasculature, and by HMEC-1, a microvascular endothelial cell line. PZ was quantified bya specific ELISA in the supernatant and in the lysates of both cellular types. Western blotting of the supernatants showed the presence of a band of 62 kDa,identical to PZ synthesized by the hepatoma cell line HepG2. mRNA of PZ was also detected in each cellular type. PZ biosynthesis was unaffected by inflammatory cytokines in HUVEC, whereas a slight decrease of mRNA and PZ antigen (53.5 ± 14.5% of protein synthesis as compared to the control, p < 0.01) and a modest increase (126± 8.5% as compared to the control, p< 0.05) were induced respectively byTumor Necrosis Factor (TNF)-alpha (25 ng/ml) and oncostatin M (5 ng/ml) in HMEC-1. Immunological studies showed the presence of PZ near the nucleus and a possible expression of PZ at the membrane.In addition, PZ was present in the endothelial cells of both normal arterial and venous vessel sections. In contrast, neither ZPI nor its mRNA was detected in endothelial cells.
Re-conceptualizing Civil Society: The Debate Continues With Specific Reference to Contemporary Senegal
Authors: Lo Mbaye
Published: February 2006

This article challenges the civil society argument based on its failure to correctly and appropriately conceptualize Africa's societal experiences. To this end, the article explores Senegal as a case study to show how the idiosyncrasy of societal development has constructed and produced different types of associational life that is not grasped within the liberal preconditions of civil society. Senegal was selected to make a deductive analysis. If we can prove that Senegalese society, which is commonly cited in the liberal argument as a vibrant model of civil society, is neither acting within the conventional frameworks nor meets the conventional preconditions of civil society, the argument on the flaws of the liberal conception of civil society will stand.
Census in Nigeria: The Politics and the Imperative of Depoliticization
Authors: Mimiko Femi
Published: February 2006

This paper demonstrates that the persistent (mis)management of census is a key variable in the pattern of political instability and diminishing capacity that have defined the Nigerian State since it attained relative political independence in 1960. With roots in the highly exploitative and manipulative colonial enterprise, the crises of census in Nigeria continue to be sustained in contemporary times by the inherited contradictions that define the nation's political economy. Thus every past census in Nigeria has been a victim of intense elite contestation for power and resources, and therefore rather than enhance the planning and development process of the country, has further impaired it. The paper argues that any census, the scheduled 2005 edition inclusive, conducted in the context of extant hotly-disputed and largely illegitimate State structure, will not be able to accomplish its set objectives; with the decision by the Nigerian State to deny rather than come to terms with Nigerians' primary forms of identity, ethnic and religious, set to further erode rather than enhance the integrity of the exercise. It concludes that census will stop being inverted in its role in Nigeria only when the governance structure becomes wholly decentralized, the federating units become truly so, and census as an exercise becomes wholly de-politicized.
South Asians in East Africa (1880-1920) with a Particular Focus on Zanzibar: Toward a Historical Explanation of Economic Success of a Middlemen Minority
Authors: Oonk Gijsbert
Published: February 2006

The main object of this article is to falsify the common historical portrait of South Asians in Zanzibar and East Africa. Most studies, a-priori, assume the outstanding business success of the Asian minority in East Africa. In explaining this success, they emphasize common explanations and theories for their economic success, like hard work, having a superior business mind, using their ethnic resources for capital accumulation and knowledge of (international) markets. In this article I attempt to explain the success of South Asians in Zanzibar, East Africa, from a historical point of view. My main argument is that South Asians started with a far more favorable socio-economic position as compared to their African counterparts. They were more than Swahilis, accustomed with a money economy and the concept of interest. In addition, they knew how to read, write and produce account books. Finally, they had access to the rulers, and were able to negotiate profitable terms of trade. Nevertheless, many were not successful at all and went bankrupt. Therefore, the success of South Asians in East Africa may be explained as the outcome of a 'trial and error' process. The successful remained in East Africa, whereas others left. India remained a safety net for those who did not make out as well as a source for new recruitment of traders, shopkeepers and clerks.
The Economy of Conflict in the Oil Rich Niger Delta Region of Nigeria
Authors: Ikelegbe Augustine
Published: February 2006

Economies of war underpinned by greed and opportunities have been posited to underlie causality, dynamics and the sustenance of conflicts – particularly Africa's resource wars. This study examines the economy of conflict in the resource conflicts in the Niger Delta region of Nigeria. It found that a conflict economy comprising an intensive and violent struggle for resource opportunities, inter and intra communal/ethnic conflicts over resources, and the theft and trading in refined and crude oil has blossomed since the 1990s. This paper examines the interfaces between the Nigerian state, multinational oil companies, the international community, and youth militias with the economy. This paper found that though the economy did not cause the conflict, it has become a part of the resistance and a resource for sustaining it. The economy underpins an extensive proliferation of arms and the institutions of violence and the pervasiveness of crime, violence and communal/ethnic conflicts.
Preparation of Very Reactive Thiol-Protected Gold Nanoparticles: Revisiting the Brust-Schiffrin Method
Authors: Araki Koiti , Mizuguchi Eisuke , Tanaka Hirofumi , Ogawa Takuji
Published: February 2006

The preparation and properties of tert-dodecanethiol protected gold nanoparticles amenable to very rapid surface functionalization by associative mechanism is described. The new material can be easily prepared by controlling the reaction time, because only a limited but enough
number of tert-dodecanethiol to stabilize the gold clusters is bond to the surface until about an hour. Accordingly, it can be isolated as a solid and handled much like the highly stabilized Brust-Schiffrin analogues, but reacted very rapidly with any molecular species containing one
or multiple functional groups such as thiol, disulfide, pyridine, etc., These characteristics are ideal for the preparation of a variety of new organic–inorganic hybrid nanomaterials by coordinative self-assembly. This possibility was illustrated using meso-tetra(4-pyridyl)porphyrin,
which promptly bonded to the reactive protected gold nanoparticles generating a solid that can be grown as thin films with layer-by-layer control on a suitably modified surface.
Layer-by-Layer Nanocoating of Lignocellulose Fibers for Enhanced Paper Properties
Authors: Zheng Zhiguo , McDonald John , Khillan Rajneek , Su Yi , Shutava Tatsiana , Grozdits George , Lvov Yuri M.
Published: February 2006

The systematic modification of the surface charge of lignocellulose fibers was performed with a polyelectrolyte layer-by-layer (LbL) nanocoating process to produce negatively and positively charged fibers. The fibers were coated with 20–50 nm thick polymer surface layers which
subsequently increased interaction between the fibers during paper formation. The modified fibers were added to standard fibers at varying proportions to produce paper with corresponding variation in properties such as strength and electrical conductivity. Paper strength was doubled by manipulating
the surface charge and coating thickness of the LbL-treated pulp fibers. It is demonstrated that the LbL coating process increased the fiber interactions and that these interactions enhanced the paper properties. This process, when applied to a simulated sample of recycle grade of fibers,
produce paper with an increase in tear strength as compared with untreated fiber paper. Nanocoating fibers with polythiophene/polyallylamine multilayers produced marginally conductive pulp and paper. Paper electrical conductivity was proportional to the number of the bilayers deposited.
In-Situ Preparation of Binary-Phase Silver Nanoparticles at a High Ag+ Concentration
Authors: Ullah Md. Habib , Kim Il , Ha Chang-Sik
Published: February 2006

Stable and monodisperse silver nanoparticles (NPs) have been synthesized using high metal salt concentration (up to 0.735 M) through a simple but novel technique. It is based on one-step procedure that uses glycerol for reducing Ag+ in the presence of o-phenylenediamine
(o-PDA) resulting the nanoparticles are in two forms (one water-soluble, the other a precipitated). The water-soluble phase contains NPs that have a bimodal size distribution (2–3 and 5–6 nm); the other comprises precipitated NPs, having a unimodal size distribution (2–3
nm). The water-soluble NPs are covalently bonded to the aromatic amine molecules to form isolated units, while the precipitated nanoparticles are embedded in the networks formed by cross-linking between COOH groups of hydroxypyruvic acid (oxidized form of glycerol) and NH2 groups
of o-PDA molecules. We used transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) to characterize the silver products obtained.
Electrochemical Hydrogen Storage in Single-Walled Carbon Nanotube Paper
Authors: Guo Z. P. , Ng S. H. , Wang J. Z. , Huang Z. G. , Liu H. K. , Too C. O. , Wallace G. G.
Published: February 2006

Single-walled carbon nanotube (SWNT) papers were successfully prepared by dispersing SWNTs in Triton X-100 solution, then filtered by PVDF membrane (0.22 μm pore size). The electrochemical behavior and the reversible hydrogen storage capacity of single-walled carbon nanotube
(SWNT) papers have been investigated in alkaline electrolytic solutions (6 N KOH) by cyclic voltammetry, linear micropolarization, and constant current charge/discharge measurements. The effect of thickness and the addition of carbon black on hydrogen adsorption/desorption were also investigated.
It was found that the electrochemical charge–discharge mechanism occurring in SWNT paper electrodes is somewhere between that of carbon nanotubes (physical process) and that of metal hydride electrodes (chemical process), and consists of a charge-transfer reaction (Reduction/Oxidation)
and a diffusion step (Diffusion).
Aerosol Phase Generation of Indium–Selenide Nanoparticles
Authors: Geretovszky Zs. , Deppert K. , Karlsson L. S. , Karlsson M. N. A. , Malm J.-O. , Mühlberg M.
Published: February 2006

Results on the generation and heat treatment of In–Se nanoparticles, made by heterogeneous condensation of selenium on indium nanoparticles synthesised via the evaporation/condensation route are reported. In-situ aerosol measurements are complemented with ex-situ
analysis, to provide structural, morphological, and compositional information on the In–Se nanoparticles. Our results indicate that prior to heat treatment In–Se nanoparticles have a shape in the aerosol phase, similar to an asymmetric dumbbell. The bigger particle of the dumbbell
structure is made up of amorphous Se, while the overall composition of the polycrystalline smaller particle is around InSe. The smaller particle has an intrinsic structure, and consists of different InSe-compounds, with a decreasing In content towards the shell. The shape of the In–Se
nanoparticles is different in the aerosol phase and on the surface of the samples. The observed variety of particle sizes and shapes on the sample surface is shown to be partly due to the agglomeration of the aerosol phase binaries (i.e., dumbbells) via coalescence on the surface of the sample
and wetting of the sample surface by the Se nanoparticles. These processes make the bigger particle of the dumbbell structure appear almost perfectly hemispherical on the sample surfaces. During heat treatment at lower temperatures mainly the evaporative removal of the big Se particle of the
dumbbell structure will take place. Annealing of the smaller particles starts to dominate at temperatures above 240 °C and makes the composition of the small particles closer to that of the thermodynamically most favoured In2Se3.
Conductive Super-Hydrophobic Surfaces of Polyaniline Modified Porous Anodic Alumina Membranes
Authors: Chen Xinhua , Chen Guangming , Ma Yongmei , Li Xinhong , Jiang Lei , Wang Fosong
Published: February 2006

A conductive polymer polyaniline (PANI) was employed to achieve surfaces of both super-hydrophobic and conductive on NaOH etched porous anodic alumina (PAA) membranes. The surfaces exhibit micro- and nanostructures. In the PANI modified PAA membrane, PANI is mainly emeraldine. After
the membrane was immersed in HCl, the content of the protonated nitrogen increased, which increased the conductivity.
Controlled Synthesis and Field Emission Properties of ZnO Nanostructures with Different Morphologies
Authors: Huang Y. H. , Zhang Y. , Liu L. , Fan S. S. , Wei Y. , He J.
Published: February 2006

By simply controlling atmosphere, rods, tetraleg-rods, and arrays of ZnO nanostructures have been fabricated respectively through pure zinc powder evaporation without catalyst at temperature of 650 &sim 700 °C. Investigations through HRTEM and XRD showed that the growth of the
synthesized ZnO nanostructures was controlled by vapor-solid mechanism. Field emission measurements revealed that all of the structures, owing to their very low turn-on voltage, sufficient emission current and proper linearity of 1/V ∼ Ln(I/V2), are likely to be potential candidates
as a field emitter. The results also indicated that field emission properties are relative to morphology and size of the tips of ZnO nanostructures, and the nanorods with sharp tips possess the first-class FE property.
Encoding Information Using Molecular Vibronics
Authors: Yan Liuming , Ma Yuefei , Seminario Jorge M.
Published: February 2006

Signals carrying information are encoded in molecular vibrational waves (vibronics) rather than in electric currents as widely done in microelectronics. We demonstrate theoretically that signals can be transmitted along a long polypeptide molecule; the signal is modulated in a terahertz
carrier corresponding to a frequency of an intrinsic vibrational mode of the backbone of the polypeptide, via amplitude and frequency modulations. The modulated carrier is coupled as a vibrational wave to the polypeptide at one end of the molecule and propagates for more than 168 Å towards
the other end. Digital signal processing techniques are used to recover the modulated signals.
Synthesis of Silica Nanowires by Active Oxidation of Silicon Substrates
Authors: Ferlauto Andre S. , Oliveira Sergio , Silva Edelma E. , Magalhaes-Paniago Rogerio , Ladeira Luiz O. , Lacerda Rodrigo G.
Published: February 2006

Amorphous silica nanowires have been produced by thermal annealing of Si/SiO2/Ni substrate structures at 900 °C under an atmosphere of hexamethyldisilazane (HMDS) and hydrogen (H2). The wires have diameter ranging from 35 to 55 nm, which are controlled by the
Ni particle size. It is demonstrated that the growth occurs through vapor–liquid–solid mechanisms, and it is proposed that the vapor source is volatile SiO generated from the etching of the Si substrate through active oxidation reactions. The role of the HMDS-H2 atmosphere
in promoting such reactions is discussed.
Structural and Optical Properties of Tin Oxide Branched Nanostructures
Authors: Jeedigunta Sathyaharish , Singh Manoj K. , Kumar Ashok , Zekri Souheil , Bumgarner John , Rossie Benjamin
Published: February 2006

Branched nanostructures of tin oxide (SnO2) have been synthesized by Vapor–Liquid–Solid (VLS) mechanism using a gold catalyst in the temperature range of 800–850 °C under an ambient gas flow of 200 sccm. The microstructural and the optical properties
of the as prepared products have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), micro-Raman, and photoluminescence (PL) studies. SnO2 branches with a rutile phase are found to have a preferential orientation along
(101). Typical lengths of these branches are found to be approximately 3–5 μm and diameters in the range of 50–100 nm. Selected area electron diffraction (SAED) pattern shows that the SnO2 branches have a tetragonal cross section with [101] crystal direction.
A Raman line at 631 cm−1 (Sn–O bond) is obtained in the micro Raman spectra. Low temperature PL spectrum shows a strong green emission band near 506 nm.
Self-Organized CdSSe Quantum Dots Thin Films
Authors: Chaure Shweta , Chaure N. B. , Pandey R. K.
Published: February 2006

Self-organized and strained CdSSe quantum dot (Q-dot) thin films have been grown on ITO-coated glass substrates bynovel wet chemical route. The Q-dots are (002) oriented faceted pyramids with average particle size of 7.5 nm. The X-ray diffraction results reveal the formation of a solid
solution of CdSSe. Atomic force microscopy is used to investigate the morphology of the nanocrystalline thin films. The energy dispersive X-ray analysis spectrum confirms the presence of Cd, S, and Se in the films. Optical absorption and photoluminescence spectra show the blue shift for quantum
dot thin films.
Inlaying Nanoscale Surface Recess Patterns with Nanoscale Objects
Authors: Yau Siu-Tung , Thai Ngee Mei , Strauss Ela , Rana Narender , Wang Gang
Published: February 2006

A simple and versatile approach to constructing patterns on a solid surface using nanoscale objects is demonstrated. The approach is essentially an inlaying process, in which recess patterns fabricated on a surface are selectively filled with nanoscale objects. The objects are anchored
firmly on the surface due to the spatial confinement provided by the recess structures. Protein molecules and inorganic nanoparticles are used in this demonstration. Cyclic voltammetry is used to detect electron transfer signals from patterns of protein molecules. The approach suggests a potentially
fast, high-throughput and versatile technique for constructing architectural structures on a solid surface using nanoscale objects.
ZnO Nanorods on In-Situ Synthesized ZnSe Grains
Authors: Choy Wallace C. H. , Guo C. F. , Pang G. K. H. , Leung Y. P. , Wang G. Z. , Cheah K. W.
Published: February 2006

The ZnO nanorods grown on in-situ synthesized ZnSe grains through the chemical vapour deposition method are reported here for the first time. With a suitable growth condition, single crystal ZnO nanorods grow on the well-defined bounded facets of the random shape ZnSe grains using Zn
and Se powders without any metal catalyst. The growth direction of ZnSe nanorods on a facet of a ZnSe grain is quite uniform. The synthesis mechanism of the ZnO nanorods on the ZnSe grains is proposed. The effects of the Se powder usage on the ZnO–ZnSe products and the photoluminescence
of the products are investigated.
Mn-Doped Zinc Aluminate Nanoparticles: Hydrothermal Synthesis, Characterization, and Photoluminescence Properties
Authors: Mu Li , Wan Junxi , Wang Zhenghua , Gao Yongqian , Qian Yitai
Published: February 2006

A two-step synthesis method was developed to fabricate Mn-doped zinc aluminate (ZnAl2O4) nanoparticles, including the first step of ageing, and the second step of crystallization. The effects of preparation conditions, such as ageing temperature, crystallization
time, and the pH on the Mn-doped ZnAl2O4 nanoparticles were systematically investigated. The photoluminescence (PL) properties of green phosphor Mn-doped ZnAl2O4 nanoparticles were also discussed. Compared with the bulk sample, the PL spectrum of
Mn-doped ZnAl2O4 nanoparticles has distinct blue shift. This procedure provides a facile way for the synthesis of well-crystallized ZnAl2O4:Mn at low temperature.
Nanorods of Tellurium: Synthesis and Self-Assembly
Authors: Batabyal Sudip K. , Basu C. , Das A. R. , Sanyal G. S.
Published: February 2006

A simple solution phase approach is described to prepare tellurium nanorods which undergo morphological modifications to yield different microstructures under varied experimental conditions. The morphology of the prepared products is drastically altered in presence of a few oxidizing
agents such as sodium oxychloride (NaOCl), hydrogen peroxide (H2O2) etc. The effects of poly (sodium 4-styrene sulphonate) (PSS) and Isooctyl phenoxy poly oxyethanol (TritonX-100) on the size and shape of the products in presence of air/NaOCl have also been monitored.
Generation of CdS Nano-Necklaces and NiS Nanotubes Templated by Sugar-Appended Hydrogel
Authors: Bao Chunyan , Lu Ran , Xue Pengchong , Jin Ming , Tan Changhui , Liu Guofa , Zhao Yingying
Published: February 2006

A new hydrogel based on glucose-appended Schiff base derivative has been employed as the template to synthesize CdS and NiS nanostructures with different morphologies. The FT-IRand UV-vis results revealed that H-bonding and π–π interaction played important
roles in the formation of original hydrogel fibers. The study of mineralization mechanism suggested that the inorganic ions were firstly adsorbed at the surface of the hydrogel fibers due to the hydrophilic affinity with the hydrophilic glucose groups. With the penetration of H2S
gas, the preformed CdS or NiS nanoparticles on the surface of the fibers acted as the growing points for the continuous growth. And the different adsorption abilities of the metal ions at the hydrogel fibers resulted in the formation of CdS nano-necklaces and NiS nanotubes.
Focused Ion Beam Nanofabrication: A Comparison with Conventional Processing Techniques
Authors: Langford R. M.
Published: February 2006

Focused ion beam and dual platform systems are versatile tools for nanoengineering and nano-science applications. These systems complement conventional processing methods and can be used to prototype and modify a diverse range of nano-devices and sensors. This article discusses FIB
nanofabrication and compares it with other fabrication techniques such as electron beam lithography and reactive ion etching. Aspects such as the minimum feature size and side wall profiles are discussed and compared. In addition, the limitations and detrimental effects of FIB processes are
discussed.
Self-Surface Passivation of CdX (X = Se, Te) Quantum Dots
Authors: Jose Rajan , Zhelev Zhivko , Nagase Toshimi , Bakalova Rumiana , Baba Yoshinobu , Ishikawa Mitsuru
Published: February 2006

A small portion of a reaction mixture including unpurified CdX (X = Se or Te) quantum dots (QDs), in which unreacted Cd and Se ions were left together with coordinating solvents, was dropped into an organic solvent. The CdX QDs in this organic solution showed enhancement of photoluminescence
(PL) efficiency, growth of particles, and focusing of size distribution for more than 10 h at room temperature (RT, ∼23 °C). These effects were attributed to passivation of QDs' surface by Cd and X ions present in the solution. No external energy source was used for these achievements;
therefore, the process is termed as self-surface passivation. The self-surface passivation was reproduced using purified CdX QDs with additional Cd and X ions in an organic solvent. The self-surface passivation method was applied to RT-synthesized CdSe QDs, which is characterized by a broad
PL spectrum (fwhm ∼ 150 nm) for monodispersed QDs, to modify their emission characteristics. On self-surface passivation, the broad PL spectrum was narrowed (fwhm ∼ 35 nm) and the QDs were grown. The X-ray diffraction measurements of RT-synthesized CdSe QDs and that subsequently aged
in 1-butanol showed that crystallinity of the samples was improved on aging.
Room Temperature Formation of Ammonia by Oxidizing Hydrogenated Cerium Nanoparticles in the Air
Authors: Zhang Yaohua , Liu Tong , Wang Zhong , Li Yan , Li Xingguo
Published: February 2006

Ammonia formation was observed when hydrogenated cerium nanoparticles prepared by hydrogen plasma-metal reaction (HPMR) were exposed to the air at room temperature. This novel phenomenon represents a successful example of room temperature cleavage of dinitrogen and may find application
in low temperature synthesis of ammonia under thermodynamically favorable conditions. A possible mechanism is also proposed. We suggest that the oxidation of cerium hydride offers chemical force to drive the hydrogen atoms out of the lattice. The monoatomic H released to the surface is highly
active and readily reacts with N2 to yield ammonia. Some surface processes, which we know little about at the moment, are likely to be involved so as to lower the energy barrier of nitrogen dissociation. Further investigation is required to elucidate the detailed mechanism.
Controlled Synthesis of Manganese Oxohydroxide (MnOOH) and Mn3O4 Nanorods Using Novel Reverse Micelles
Authors: Dong Xiyan , Zhang Xingtang , Liu Bing , Wang Hongze , Li Yuncai , Huang Yabin , Du Zuliang
Published: February 2006

Novel reverse micelles of high CTAB concentration were successfully developed to synthesize MnOOH (manganese oxyhydroxide) nanorods with uniform diameters of about 10 nm and up to 200 nm in length under mild solution conditions and Mn3O4 nanorods with the same
morphology could be obtained by calcining the precursors at 450 °C. The morphology and microstructure of the nanorods were investigated by transmission electron microscopy (TEM and HRTEM), XRD and TGA. The results showed that the concentration of CTAB was a key factor for the formation
of MnOOH nanorods and only above 0.2 M the nanorods could be obtained. Moreover, the length of nanorods increased with the increase of CTAB concentration, while the diameter of nanorods retained steadily. In this way, the length of nanorods could be easily controlled from tens nanometers to
hundreds nanometers by increasing the CTAB concentration from 0.35 M to 1.25 M. In addition, in our experiment the products were almost entirely rod-like shape, which indicated this method should be suitable for mass-producing.
Preparation of Vermiculite Nanoparticles Using Thermal Hydrogen Peroxide Treatment
Authors: Weiss Zdeněk , Valášková Marta , Seidlerová Jana , Šupová-Křístková Monika , Šustai Ondřej , Matějka Vlastimil , Čapková Pavla
Published: February 2006

Powdered natural Mg-vermiculite (Letovice, Czech Republic), with the formula (Mg0.35K0.02Ca0.01) (Mg2.39Fe3+0.51Fe2+0.02Al0.08) (Si2.64Al1.33Ti0.03) O10(OH)2·4.97H2O
and particle size <5 μm, was used for the investigation of exfoliation after hydrogen peroxide and/or microwave treatment (600 W). A sample heated in the microwave oven for 40 min exhibits a 11% mass loss and reduction of the 001 peak intensity in the X-ray diffraction pattern.
The basal 001 peak intensity of untreated Mg-vermiculite sample (I001 = 100%) drops to 35% in the microwave treated sample. Only the sample treated for 5 h at 80 °C fully rehydrated after 120 min at room temperature. A more pronounced reduction of the 001 peak intensity
(to 8%) was observed after hydrogen peroxide treatment of the sample at 25 °C. The combination of a five-hour hydrogen peroxide treatment at 80 °C and subsequent microwave heating leads to an effective extinction of the 001 diffraction in the XRD pattern. The 001 diffraction profile
becomes very diffuse with peak intensity less than 1%. The degree of reduction of the 001 diffraction intensity also depends on the time and temperature of hydrogen peroxide treatment and on the peroxide concentration. An even more pronounced reduction of the peak intensity is caused by exfoliation
of particles to nano-domains coupled with a randomization of the c-axes.
Synthesis and Characterization of Ultrafine Poly(vinylalcohol phosphate) Coated Magnetite Nanoparticles
Authors: Mohapatra Sasmita , Pramanik Nabakumar , Ghosh Sudip K. , Pramanik Panchanan
Published: February 2006

Nanosized magnetite (Fe3O4) particles showing superparamagnetism at room temperature have been prepared by controlled coprecipitation of Fe2+ and Fe3+ in presence of highly hydrophilic poly(vinylalcohol phosphate)(PVAP). The impact of polymer
concentration on particle size, size distribution, colloidal stability, and magnetic property has been extensively studied. The aqueous suspension of magnetite, prepared using 1% PVAP solution is stable for four weeks at pH 5–8. X-ray diffractograms show the formation of nanocrystalline
inverse spinel phase magnetite. Transmission Electron Microscopy confirmed well dispersed cubic magnetite particles of size of about 5.8 nm. Dynamic Light Scattering measurement shows narrow distribution of hydrodynamic size of particle aggregates. Infrared spectra of samples show strong Fe—O—P
bond on the oxide surface. UV-visible studies show aqueous dispersion of magnetite formed by using 1% PVAP solution is stable at least for four weeks without any detoriation of particle size. Magnetization measurements at room temperature show superparamagnetic nature of polymer coated magnetite
nanoparticles.
Growth and Observation of Low-Field Giant Magnetoresistance in La0.7Sr0.3MnO3/ZnO Superlattice Structures
Authors: Tiwari Ashutosh , Narayan J.
Published: February 2006

We report the growth of a new class of superlattice structure, consisting of alternate layers of La0.7Sr0.3MnO3 (LSMO) and ZnO, which exhibits giant magnetoresistance at low fields. These superlattices were fabricated using a novel pulsed-laser deposition
technique with a specially designed target assembly. Giant magnetoresistance of >250% has been observed in these structures in current-in-plane configuration on the application of just ∼400 Gauss of magnetic field over the broad temperature range 15–200 K. Observation of giant
magnetoresistance at such low magnetic fields is a groundbreaking step in the field of novel magnetic materials and devices.
Synthesis and Luminescence Properties of Lanthanide (III)-Doped YF3 Nanoparticles
Authors: Cui Yang , Fan Xianping , Hong Zhanglian , Wang Minquan
Published: February 2006

Synthesis process and luminescence properties of trivalent lanthanide ions (Ln3+) doped YF3 nanoparticles have been investigated. To synthesis Ln3+-doped YF3 nanoparticles, the mixture of (YCl3·nH2O + LnCl3·nH2O),
and NH4F was hydrothermal treated at 180 °C in a Teflon-liner auto-clave or heated at higher temperatures (400 °C ∼ 600 °C) in a stove. The XRD patterns showed that the Ln3+-doped orthorhombic YF3 nanoparticles with no second phase have been
prepared. The solid solution Y1−xEuxF3 (x = 0 ∼ 0.4) nanoparticles have been synthesized. The luminescence concentration quenching resulted from resonance energy transfer between neighboring Eu3+ ions occurred at higher
Eu3+ concentrations (30 mol%). The upconversion luminescence of Er3+−Yb3+ codoped YF3 nanoparticles under 980 nm excitation has also been observed. With increase of heated temperature, the size of the Er3+−Yb3+ codoped
YF3 nanoparticles increased gradually, and upconversion luminescence intensity increased significantly.
A Simple and Rapid Method of Making 2D and 3D Arrays of Gold Nanoparticles
Authors: Fernandez Carlos A. , Wai Chien W.
Published: February 2006

Monodispersive gold nanoparticles can be synthesized by a dropwise addition of a reducing agent microemulsion to a gold ion microemulsion followed by immediate stabilization with 1-decanethiol. No size-selective precipitations or digestive ripening procedures are necessary. There is
no need for metal functionalization of the surfactant AOT. Gold nanoparticles with an average size of 3.8 nm and a relative size dispersion of 5.4% were observed using n-heptane as a solvent. It seems possible to adjust the nanoparticle size by small changes in the carbon chain length
of the solvent. Self-assembled 2D and 3D arrays of gold nanoparticles with adjustable sizes have been obtained on carbon-coated copper grids and on a silicon wafer. The arrays have good crystallinity as evidenced by the external morphology and transmission electron diffraction results. The
size of the gold nanoparticle 3D arrays depends on the immersion time and can be greater than 15 μm. This approach could be used to synthesize other noble metal nanoparticle arrays that may lead to new materials for electronic and photonic applications.
Carbon Nanotube-Based Sensors
Authors: Sinha Niraj , Ma Jiazhi , Yeow John T. W.
Published: February 2006

Sensors continue to make significant impact in everyday life. There has been a strong demand for producing highly selective, sensitive, responsive, and cost effective sensors. As a result, research emphasis is on developing new sensing materials and technologies. Carbon nanotubes (CNTs)
have many distinct properties that may be exploited to develop next generation of sensors. This manuscript reviews the distinct physical, electronic, and mechanical properties of CNTs. The main thrust of this review is to highlight the present and future research and development work in the
area of carbon nanotube sensors for real-world applications. The technical challenges associated with CNT-based sensors, which remain to be fully addressed, have also been outlined at the end of the manuscript. This review aims to act as a reference source for researchers to help them in developing
new applications of CNT-based sensors.
Effect of Sodium dodecylsulfate and Dodecyltrimethyl Ammonium Bromide on the Morphologies of Gold Nanoparticles in the Presence of Poly(amidoamine) Dendrimers
Authors: Bakshi Mandeep Singh , Kaura Aman , Kaur Gurinder , Torigoe Kanjiro , Esumi Kunio
Published: February 2006

The synthesis of gold nanoparticles has been carried out in aqueous phase in the presence of both ionic surfactants (i.e., sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTAB)) and poly(amidoamine) dendrimers (PAMAM). It has been observed that the fluoroderivative
of 2G PAMAM (2D) acts as reducing agent in reducing Au(III) to Au(0) leading to the formation of fine gold nanoparticles. This process has been further evaluated in the presence of fixed amounts of both SDS and DTAB in their respective pre and post micellar concentration regions. The presence
of SDS leads to the appearance of clear ordered morphologies such as triangular, hexagonal, spherical, and rod shaped, while the presence of DTAB does not show this effect. The formation of nanoparticles in triangular morphologies is more significant in the premicellar concentration range
of SDS whereas hexagonal morphologies in the post micellar concentration range. On the contrary, increase in the DTAB concentration from pre to post micellar range only reduces the size of gold nanoparticles without the appearance of any ordered morphology. The formation of ordered gold nanoparticles
in the presence of SDS has been further attributed to the significant SDS-dendrimer interactions and an appropriate mechanism has been proposed to justify the results.
Thermal Diffusivity of Nanofluids Containing Au/Pd Bimetallic Nanoparticles of Different Compositions
Authors: Sánchez-Ramírez J. F. , Pérez J. L. Jiménez , Orea A. Cruz , Fuentes R. Gutierrez , Bautista-Hernández A. , Pal U.
Published: February 2006

Colloidal suspensions of bimetallic Au/Pd nanoparticles were prepared by simultaneous reduction of the metal ions from their corresponding chloride salts with polymer (PVP) stabilizer. Thermal properties of water containing bimetallic nanoparticles with different nominal compositions
(Au/Pd = 12/1, 5/1, 1/1, 1/5) were measured using the mode mismatched dual-beam thermal lens technique to determine the effect of particle composition on the thermal diffusivity of the nanofluids. The characteristic time constant of the transient thermal lens was estimated by fitting the experimental
data to the theoretical expression for transient thermal lens. The thermal diffusivity of the nanofluids (water, containing Au/Pd bimetallic nanoparticles) is seen to be strongly dependent on the composition of the particles. The maximum diffusivity was achieved for the nanoparticles with
highest Au/Pd molar ratio. A possible mechanism for such high thermal diffusivity of the nanofluids with bimetallic particles is given. UV-Vis spectroscopy, TEM and high-resolution electron microscopy (HREM) techniques were used to characterize the Au/Pd bimetallic nanoparticles.