bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical and morphological properties of organic–inorganic, hybrid, clay‐filled, and cyanate ester/siloxane toughened epoxy nanocomposites
Authors: Nagendiran S. , Premkumar S. , Alagar M.
Published: July 2007

Organic–inorganic hybrids involving cyanate ester and hydroxyl‐terminated polydimethylsiloxane (HTPDMS) modified diglycidyl ether of bisphenol A (DGEBA; epoxy resin) filled with organomodified clay [montmorillonite (MMT)] nanocomposites were prepared via in situ polymerization and compared with unfilled‐clay macrocomposites. The epoxy‐organomodified MMT clay nanocomposites were prepared by the homogeneous dispersion of various percentages (1–5%), and the resulting homogeneous epoxy/clay hybrids were modified with 10% HTPDMS and γ‐aminopropyltriethoxysilane as a coupling agent in the presence of a tin catalyst. The siliconized epoxy/clay prepolymer was further modified separately with 10% of three different types of cyanate esters, namely, 4,4′‐dicyanato‐2,2′‐diphenylpropane, 1,1′‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, and 1,3‐dicyanato benzene, and cured with diaminodiphenylmethane as a curing agent. The reactions during the curing process between the epoxy, siloxane, and cyanate were confirmed by Fourier transform infrared analysis. The results of dynamic mechanical analysis showed that the glass‐transition temperatures of the clay‐filled hybrid epoxy systems were lower than that of neat epoxy. The data obtained from mechanical studies implied that there was a significant improvement in the strength and modulus by the nanoscale reinforcement of organomodified MMT clay with the matrix resin. The morphologies of the siloxane‐containing, hybrid epoxy/clay systems showed heterogeneous character due to the partial incompatibility of HTPDMS. The exfoliation of the organoclay was ascertained from X‐ray diffraction patterns. The increase in the percentage of organomodified MMT clay up to 5 wt % led to a significant improvement in the mechanical properties and an insignificant decrease in the glass‐transition temperature versus the unfilled‐clay systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Shade darkening effect of polyorganosiloxane modified with amino and hydroxy groups on dyed polyester microfiber fabric
Authors: Xie Kongliang , Yu Jibin , Jiang Denghui
Published: July 2007

The novel polyorganosiloxane material S‐101 modified with amino and hydroxy groups is synthesized. Shade darkening effect of modified polyorganosiloxane on dyed polyester microfiber fabric is investigated by reflectance spectrum, color yield (K/S), and the color differences (ΔE). The colorimetric data of CIELAB is discussed. The results show that the novel material of silicone polymer modified with amino and hydroxy groups has excellent shade darkening effect on dyed polyester microfiber fabric. The rates of the color yield increase (I%) of all dyed fabric with four dyes (Disperse Yellow S‐4RL, Red GS, Blue 2BLN, and Black SF‐R) exceed 10%. The shapes of the reflectance spectra curves of the dyed fabrics before and after treated with S‐101 are not noticeable change. The dyed fabrics with the polymer have not significant effect on the wash fastness and wet rubbing fastness. The low reflectance thin film on dyed fabrics is formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
On a compounding assets model with positive jumps
Authors: Dong Yinghui , Wang Guojing
Published: July 2007

In this paper, a compounding assets model with positive jumps is proposed. Integral equations and integro‐differential equations for the survival probability and the ruin probability for the proposed model are derived. By using a probability method, an exact expression in the form of series for the ruin probability is obtained. Some closed‐form expressions for the survival probability are deduced by solving certain integro‐differential equations. Copyright © 2007 John Wiley & Sons, Ltd.
Haematopoietic stem cell niche in Drosophila
Authors: Koch Ute , Radtke Freddy
Published: July 2007

Development and homeostasis of the haematopoietic system is dependent upon stem cells that have the unique ability to both self‐renew and to differentiate in all cell lineages of the blood. The crucial decision between haematopoietic stem cell (HSC) self‐renewal and differentiation must be tightly controlled. Ultimately, this choice is regulated by the integration of intrinsic signals together with extrinsic cues provided by an exclusive microenvironment, the so‐called haematopoietic niche. Although the haematopoietic system of vertebrates has been studied extensively for many decades, the specification of the HSC niche and its signals involved are poorly understood. Much of our current knowledge of how niches regulate long‐term maintenance of stem cells is derived from studies on Drosophila germ cells. Now, two recently published studies by Mandal et al.1 and Krezmien et al.2 describe the Drosophila haematopoietic niche and signal transduction pathways that are involved in the maintenance of haematopoietic precursors. Both reports emphasize several features that are important for controlling stem cell behavior and show parallels to both the vertebrate haematopoietic niche as well as the Drosophila germline stem cell niches in ovary and testis. The findings of both papers shed new light on the specific interactions between haematopoietic progenitors and their microenvironment. BioEssays 29:713–716, 2007. © 2007 Wiley Periodicals, Inc.
New roads lead to Rubisco in archaebacteria
Authors: Mueller‐Cajar Oliver , Badger Murray Ronald
Published: July 2007

The discovery of the CO2‐fixing enzyme Rubisco in the Archaebacteria has presented a conundrum in that they apparently lack the gene for phosphoribulokinase, which is required to generate Rubisco's substrate ribulose 1,5‐bisphosphate (RuBP). However, two groups1, 2 have now demonstrated novel RuBP synthesis pathways, demystifying Rubisco's non‐autotrophic and perhaps ancient role. A new CO2 fixing role for Rubisco, which is distinct from the globally dominant Calvin cycle, is providing important clues furthering our understanding of the evolution of autotrophy. This perspective is strengthened by the additional recognition in this commentary that some Rubisco‐containing Archaea do also contain PRK and may represent an interesting autotrophic evolutionary transition. Supplementary material for this article can be found on the BioEssays website (http://www.interscience.wiley.com/jpages/0265‐9247/suppmat/index.html). BioEssays 29:722–724, 2007. © 2007 Wiley Periodicals, Inc.
Insulin resistance is an evolutionarily conserved physiological mechanism at the cellular level for protection against increased oxidative stress
Authors: Erol Adnan
Published: July 2007

Several protective cellular mechanisms protect against the accumulation of reactive oxygen species (ROS) and the concomitant oxidative stress. Therefore, any reduction in glucose or fatty acid flux into cells leading to a decrease in the production of reducing equivalents would also lead to a decreased ROS production and protect cells against oxidative stress. In the presence of insulin, FOXO proteins are localized from the nucleus to the cytoplasm and degraded. An increase in cellular glucose uptake will lead to increased production of ROS. This in turn activates the stress‐responsive Jun‐N‐terminal kinase (JNK), which promotes nuclear translocation of FOXO proteins, upregulating some important target genes including stress resistance. Consequently, insulin resistance should result in decreased cellular ROS production. For this reason, insulin resistance could be a physiological mechanism activated at the cellular level in response to conditions stimulating ROS production and leading to the prevention of oxidative stress, and extension of life. Concerning the whole organism, however, IR is a maladaptive process in the long term causing a diabetic state. BioEssays 29:811–818, 2007. © 2007 Wiley Periodicals, Inc.
Metabolic engineering of ketocarotenoid biosynthesis in leaves and flowers of tobacco species
Authors: Gerjets Tanja , Sandmann Manuela , Zhu Changfu , Sandmann Gerhard
Published: July 2007

Ketocarotenoids and especially astaxanthin are high‐valued pigments used as feed additives. Conventionally, they are provided by chemical synthesis. Their biological production is a promising alternative. For the development of a plant production system,Nicotiana glauca, a species with carotenoid‐containing yellow pigmented flower petals, was transformed with a cyanobacterial ketolase gene. The resulting plants accumulated 4‐ketozeaxantin (adinoxanthin), which is the first ketocarotenoid synthesized in flower petals by genetic modification. Due to the very late flowering in this tobacco species,N. tabacumwas used to optimize the yield and ketocarotenoid product pattern by metabolic engineering of the ketolation steps of carotenogenesis. The highly carotenogenic nectary tissue in the flowers represents a model of a flower chromoplast system. By expression of a ketolase gene, it was possible to engineer the biosynthetic pathway towards the formation of 3'‐hydroxyechinenone, 3‐hydroxyechinenone, 4‐ketozeaxanthin, 4‐ketozeaxanthin esters, 4‐ketolutein and 4‐ketolutein esters. Some of these ketocarotenoids were also formed in the leaves of the trangenic plants. In particular, by co‐expression of the ketolase gene in combination with a hydroxylase gene under an ubiquitous promoter, the formation of total carotenoids in nectaries increased by more than 2.5‐fold. In the nectaries of this type of transformants, more than 50% of the accumulating carotenoids were keto derivatives. In addition, the levels of ketocarotenoid esters were much lower and a higher percentage of the free ketocarotenoids accumulated. These results open new promising perspectives for a successful metabolic engineering of keto‐hydroxy carotenoid production in carotenogenic flowers.
Learning curve of combined modality treatment in peritoneal surface disease
Authors: Smeenk R M , Verwaal V J , Zoetmulder F A N
Published: July 2007

Background

Cytoreductive surgery with intraperitoneal chemotherapy has emerged as a new standard approach for peritoneal surface disease. This study investigated the learning curve of this combined modality treatment at a single institute.

Methods

Variables analysed over three consecutive treatment periods (1996–1998, 1999–2002 and 2003–2006) included number of abdominal regions affected, Simplified Peritoneal Cancer Index (SPCI) score, result of cytoreduction, morbidity, duration of hospital stay and survival.

Results

A total of 323 procedures were performed between January 1996 and June 2006, 184 for peritoneal carcinomatosis of colorectal cancer origin and 139 for pseudomyxoma peritonei (PMP), including second procedures in 11 patients with PMP. The mean SPCI score decreased significantly over the study period (P < 0·001), but the number of regions affected did not. The rate of complete cytoreductions increased from 35·6 to 65·1 per cent (P = 0·012). The postoperative morbidity rate decreased from 71·2 to 34·1 per cent (P < 0·001). The median duration of hospital stay decreased from 24 to 17 days. The peak of the learning curve, graded by the percentage of complete cytoreductions, was reached after approximately 130 procedures.

Conclusion

The learning curve of combined modality treatment for peritoneal surface disease is long, and reflects patient selection and treatment expertise.
Improving forensic tribunal decisions: the role of the clinician
Authors: McKee Shari A. , Harris Grant T. , Rice Marnie E.
Published: July 2007

Three empirical investigations of forensic decision‐making were conducted: a study of 104 hearings by a forensic tribunal; an evaluation of which aspects of forensic patients' clinical presentation were empirical predictors of violence; and a survey of forensic clinicians to determine which factors they said they used to assess risk of violent recidivism and which they actually used. Results showed a significant correlation between actuarial risk and clinical advice to the tribunal, and a nonsignificant trend for patients higher in actuarial risk to receive more restrictive dispositions. Psychotic diagnoses and symptoms were not indicators of increased risk of violent recidivism. Clinicians endorsed some empirically valid indicators of risk, but also relied on some invalid indicators. There was also inconsistency between factors clinicians said they used and factors actually related to their hypothetical decision‐making. An automated system is presented as an illustration of how the consistency and validity of forensic decisions could be enhanced. Copyright © 2007 John Wiley & Sons, Ltd.
Approximating character biomechanics with real‐time weighted inverse kinematics
Authors: Meredith Michael , Maddock Steve
Published: July 2007

In this paper we show how the expensive, offline dynamic simulations of character motions can be approximated using the cheaper weighted inverse kinematics (WIK)‐based approach. We first show how a dynamics‐based approach can be used to produce a motion that is representative of a real target actor using the motion of a different source actor and the biomechanics of the target actor. This is compared against a process that uses WIK to achieve the same motion mapping goal without direct biomechanical input. The parallels between the results of the two approaches are described and further reasoned from a mathematical perspective. Thus we demonstrate how character biomechanics can be approximated with real‐time WIK. Copyright © 2007 John Wiley & Sons, Ltd.
Nematicidal Metabolites Produced by the Endophytic Fungus Geotrichum sp. AL4
Authors: Li Guo‐Hong , Yu Ze‐Fen , Li Xuan , Wang Xing‐Biao , Zheng Li‐Jun , Zhang Ke‐Qin
Published: July 2007

From the endophytic fungal strain Geotrichum sp. AL4, cultivated from the leaves of the neem tree (Azadirachta indica), four compounds, 1–4, were isolated from the AcOEt extract, including two new, chlorinated, epimeric 1,3‐oxazinane derivatives. All compounds were assessed for their nematicidal activities against the nematodes Bursaphelenchus xylophilus and Panagrellus redivivus, and three out of the four isolates showed noticeable bioactivities.
The Effect of Ultraviolet‐Depleted Light on the Flavonol Contents of the Cactus Species Opuntia wilcoxii and Opuntia violacea
Authors: Berger John M. , Itagaki Yasuhiro , Nakanishi Koji
Published: July 2007

An early investigation at the Biosphere‐2 Laboratory, an artificial ecosystem in the Arizona desert, had shown that the flavonoid content of cacti grown in glass‐filtered solar light was lower than of cacti grown in normal solar light. This was attributed to the absence of ultraviolet (UV) radiation, which is required for flavonoid biosynthesis. In this study, two species of Opuntia cacti were grown in solar and UV‐depleted light, and their flavonol contents of different tissues were determined by HPLC. O. wilcoxii, previously raised in the absence of UV light, was exposed to normal solar light. The flavonol content of young O. wilcoxii pads was 28‐fold higher when grown in solar light as compared to UV‐depleted light. The flavonol contents of mature outer tissues were only slightly higher. O. violacea, previously raised in solar light, was also maintained in the same UV‐depleted artificial ecosystem. The flavonol content after hydrolysis of outer tissues was similar, whether grown in solar light or UV‐depleted light. We attribute these responses to different biosynthetic and metabolic rates of young vs. mature plant tissues; slow‐growing mature tissues neither produce nor metabolize compounds as quickly as immature tissues. These findings indicate that artificial ecosystems can influence the production of natural products in cultivated plants.
Estrogen‐eluting stent implantation inhibits neointimal formation and extracellular signal‐regulated kinase activation
Authors: Han Yaling , Liang Ming , Kang Jian , Qi Yanmei , Deng Jie , Xu Kai , Yan Chenghui
Published: July 2007

Objectives: The goal of this study was to evaluate the efficacy and the mechanism of 17β‐estradiol‐eluting stents on inhibiting neointimal formation of abdominal aortas in rabbits fed with high fat diet. Background: Animal experiments have shown that local delivery of estrogen reduced neointimal formation after coronary angioplasty. Preliminary trial of estrogen‐eluting stent implantation in patients with coronary disease also suggests a reduction in restenosis. Methods: We implanted 17β‐estradiol‐eluting stents, or control phosphorylcholine‐ coated stents, or bare metal stents of abdominal aortas in rabbits fed with high fat diet. Histology, immunohistochemistry, and Western blot analysis were used to assess the efficacy and mechanism of inhibiting neointimal formation of 17β‐estradiol‐eluting stents. Results: Western blot analysis revealed marked increase in ERK phosphorylation in 30 min after deployment of phosphorylcholine‐coated or bare metal stents, indicating activation of MAP kinase pathway. Immunohistochemistry showed intense staining of phospho‐ERK in the medial smooth muscle cells in stent‐implanted region. Extensive neointimal hyperplasia developed 12 weeks after stenting. In contrast, we observed significant inhibition of ERK phosphorylation and neointimal thickening in estrogen‐eluting stent‐implanted animals. Immunohistochemistry of factor VIII‐related antigen demonstrated an accelerated reendothelialization as compared with the bare metal stent or phosphorylcholine‐coated stent‐implanted controls. Conclusions: Current study suggests that estrogen‐eluting stents reduce neointimal formation and hence prevent restenosis after angioplasty possibly by inhibiting ERK activation in smooth muscle cells and promoting reendothelialization. © 2007 Wiley‐Liss, Inc.
Clinical relevance of coronary angiography at the time of percutaneous closure of a patent foramen ovale
Authors: Wahl Andreas , Praz Fabien , Seiler Christian , Windecker Stephan , Meier Bernhard
Published: July 2007

Background:

The value of incidental coronary angiography during percutaneous shunt closure to screen for asymptomatic coronary artery disease (CAD) is unknown.

Methods:

On the occasion of percutaneous closure of patent foramen ovale (PFO), incidental coronary angiography routinely offered to men >40 and women >50 years, or younger patients with particular risk patterns, was performed in 575 patients (64% men, mean age 55 ± 10 years, mean 1.5 ± 1.1 cardiovascular risk factors) without overt history, signs, or symptoms of CAD.

Results:

CAD was found in 164 patients (29%); 53 (9%) had ≥50% diameter stenoses. Thirty patients (5%) had one‐vessel, 13 (2%) two‐vessel, and 10 (2%) three‐vessel disease. Patients with CAD (n = 164) were older (60 ± 9 vs. 53 ± 10 years; P < 0.0001), more frequently male (76% vs. 59%; P = 0.0002), and had a higher body mass index (26.5 ± 4.0 vs. 25.4 ± 4.6; P = 0.006) and more cardiovascular risk factors (2.0 ± 1.1 vs. 1.2 ± 1.0; P < 0.0001). There were six procedural complications (1%). Two were unequivocally related to coronary angiography: one minor stroke (diplopia), and one iatrogenic dissection of the right coronary ostium requiring stenting. Furthermore, four arteriovenous fistulae at the puncture site requiring elective surgical closure were possibly related to coronary angiography. Forty‐five patients (8% of total) underwent percutaneous (n = 43) or surgical (n = 2) revascularization.

Conclusions:

In selected asymptomatic patients referred for percutaneous PFO closure, incidental coronary angiography discloses a rather high prevalence of clinically unsuspected CAD. These findings are relevant not only for timely revascularization but also for maintenance of long‐term antiplatelet therapy beyond the few months recommended after PFO closure. © 2007 Wiley‐Liss, Inc.
Does creatine kinase‐MB (CK‐MB) isoenzyme elevation following percutaneous coronary intervention with drug‐eluting stents impact late clinical outcome?
Authors: Javaid Aamir , Buch Ashesh N. , Steinberg Daniel H. , Pinto Slottow Tina , Roy Probal , Pichard Augusto D. , Satler Lowell F. , Kent Kenneth M. , Gevorkian Natalie , Xue Zhenyi , Suddath William O. , Waksman Ron
Published: July 2007

Background:

The incidence of postprocedural creatine kinase (CK)‐MB elevation to >3× the upper limit of normal after percutaneous coronary intervention (PCI) has been reported at rates of up to 18% in the bare metal stent era and is correlated with higher adverse cardiovascular outcomes. This study examined the incidence and prognostic significance of CK‐MB elevations after drug‐eluting stent (DES) implantation.

Methods:

The records of 2,537 patients who underwent DES implantation and completed ≥6 months' follow‐up were evaluated. Patients with acute myocardial infarction and those who presented in cardiogenic shock and had elevated cardiac enzymes at baseline were excluded from the analysis. Of these, 179 patients (7.1%) had ≥3× postprocedural CK‐MB and 2,358 patients had <3× CK‐MB elevation. The composite end point of target vessel revascularization‐major adverse cardiac events (TVR‐MACE) at 6 months was compared between groups. Univariate and multivariate regression analyses were performed to identify predictors of adverse cardiac outcomes.

Results:

The patients with CK‐MB ≥3× elevation had a higher number of diseased vessels (2.15 ± 0.86 vs. 1.81 ± 0.87; P < 0.001), higher prevalence of type C lesions (29.9% vs. 17.7%; P < 0.001), received a higher average number of stents, and total stented length (1.72 ± 0.89 vs. 1.49 ± 0.83; P < 0.001 and 37.4 ± 23.0 mm vs. 30.8 ± 20.7 mm; P = 0.0003, respectively), and had lower rates of clinical success (91.9% vs. 99.2%; P < 0.001). The 6‐month and 1‐year TVR‐MACE rates were higher for the elevated CK‐MB group (11.9% vs. 7.0%; P = 0.02 and 16.1% vs. 26.6%, respectively; P = 0.005). The rates of subacute thrombosis were also significantly higher in the group with elevated CK‐MB (0.4% vs. 3.2%, P < 0.001). Though significant CK‐MB release was a predictor of TVR‐MACE after univariate analysis, multivessel PCI, subacute stent thrombosis, total stented length, and history of prior PCI were the only predictors after multivariate regression analysis.

Conclusions:

Postprocedural CK‐MB ≥3× elevation following PCI with DES continues to be a marker for the complexity of coronary disease and lack of clinical success; and correlates with higher rates of subacute thrombosis as well as late adverse events at 6‐months and 1‐year postprocedure. © 2007 Wiley‐Liss, Inc.
Endovascular treatment of thoracic aortic disease: Mid‐term follow‐up
Authors: Tespili Maurizio , Banfi Carlo , Valsecchi Orazio , Aiazzi Luigi , Ricucci Cristina , Guagliumi Giulio , Musumeci Giuseppe , Ferrazzi Paolo , Dake Michael D.
Published: July 2007

Objective:

The aim of this study was to evaluate the mid‐term follow‐up in a cohort of patients with acute or chronic descending aortic disease treated by stent‐graft repair.

Background:

Since 1999, endovascular stent‐graft placement has been reported as an alternative treatment to surgical approach for a variety of thoracic aortic diseases; however, results beyond initial short‐term follow‐up are not widely available for the broad range of applications.

Methods:

From March 2001, 43 consecutive patients with traumatic aortic transection (group A = 16) and complicated type B aortic dissection or aneurysm (group B = 27) underwent stent‐graft implantation. All patients underwent computed tomography (CT) scan as preoperative assessment and in 26 a transesophageal echo (TEE) exam was performed.

Results:

Technically successful stent‐graft deployment was achieved in all patients. No patient required surgical conversion and no cases of paraplegia occurred. The overall in‐hospital mortality was 9.3%. A residual endoleak (type II) was detected in one group B patient who was managed conservatively. The mean follow‐up was 29 ± 8 months (range 10–48 months). No patient died during late follow‐up after hospital discharge. At 12 months, one patient (2.5%) who had stent graft repair of an aortic dissection developed an asymptomatic type I endoleak. Three asymptomatic patients with chronic dissection had a persistent retrograde perfusion of the thoracic false lumen via a distal tear(s) in the dissection septum.

Conclusion:

Our results of stent‐graft treatment of complicated and uncomplicated diseases of the descending aorta confirms that this alternative to open repair is a safe, less invasive, and relatively low risk approach. Medium‐term follow‐up results suggest that it is effective and durable therapy with low associated mortality and morbidity rates. © 2007 Wiley‐Liss, Inc.
Methanesulfenyl Fluoride, CH3SF, a Missing Link in the Family of Sulfenyl Halides: Formation and Characterization through the Matrix Photochemistry of Methyl Thiofluoroformate, FC(O)SCH3
Authors: Romano Rosana M. , Della Védova Carlos O. , Downs Anthony J.
Published: July 2007

Matrix‐isolation experiments have afforded the means of preparing the hitherto unknown sulfur(II) fluoride, methanesulfenyl fluoride, CH3SF. Broadband UV‐visible irradiation of methyl thiofluoroformate, FC(O)SCH3, isolated in a solid Ar matrix results, first, in photoisomerization of thesyninto theantiform of the molecule, and, subsequently, in the elimination of CO with the concomitant formation of CH3SF. Continued irradiation brings about tautomerization of this product with the detachment and migration of a hydrogen from the methyl group to give the molecular complex H2CS⋅⋅⋅HF. The changes have been monitored and the photoproducts detected and identified by the IR spectra of the matrices, and the conclusions confirmed: 1) with reference to the corresponding behavior of the perdeuterated molecule FC(O)SCD3; 2) by analogy with the properties of related molecules, for example, ClC(O)SCH3, CH3SCl, and H2CS⋅⋅⋅HCl, and; 3) by comparison with the vibrational properties simulated for the different molecules by ab initio and density functional theory methods.
Studies on a New Material for Hydrogen Storage and Supply by Modified Fe and Fe2O3 Powder
Authors: Wang Hui , Wang Xian‐Sheng , Wang Xin‐Zhi , Wang Xiao‐Fang , Dong Fa‐Xin , Shi Qi‐Zhen
Published: July 2007

Modified iron oxide, a new material for hydrogen storage and supply to polymer electrolyte fuel cell (PEFC), was prepared by impregnating Fe or Fe2O3 powder with an aqueous solution containing metal cation additives (Al, Cr, Ni, Co, Zr and Mo). Hydrogen storage properties of the samples were investigated. The results show that both Fe and Fe2O3 powder with additive Mo presented excellent catalytic activity and cyclic stability, and their hydrogen producing temperature could be surprisingly decreased. The temperature of forming hydrogen for the Fe2O3‐Mo at the rate of 250 µmol·min−1·Fe‐g−1 could be dramatically decreased from 527 °C before addition of Mo to 283 °C after addition of Mo in the fourth cycle. The cause for it was probably related to preventing the sinter of the sample particles. In addition, hydrogen storage capacity of the Fe2O3‐Mo can reach w=4.5% (72 kg H2/m3), close to International Energy Agency (IEA) criterion. These show the value of practical application of the Fe2O3‐Mo as the promising hydrogen storage material.
A Novel Toxicological Evaluation of TiO2 Nanoparticles on DNA Structure
Authors: Zhu Rong‐Rong , Wang Shi‐Long , Zhang Rui , Sun Xiao‐Yu , Yao Si‐De
Published: July 2007

TiO2 has been tested to be toxic to DNA under the photo‐irradiation of ultraviolet A (UVA). However, in the dark conditions, after several days of treatment with TiO2 in aqueous solution, the interaction between TiO2 and two types of DNA was detected and the mechanisms were studied by the methods of gel‐electrophoresis, IR spectroscopy and TEM. The results showed that the DNA would be bound to TiO2; the ratio of binding was related to the concentration and the treating time; the mechanism of binding is related to phosphate groups of DNA. Besides, DNA with different structure showed different degree of binding. These findings showed a new possible way through which the TiO2 nanoparticles interact with DNA.
NMR chemical shift measurements revisited: High precision measurements
Authors: Granger P. , Bourdonneau M. , Assémat O. , Piotto M.
Published: July 2007

Accurate chemical shifts are now accessible with high field NMR spectrometers. After the recall of the basic formulae, methods are proposed to measure chemical shifts with a high precision. Using two coaxial rotors at the magic angle, the necessary parameters used for correction are measured. The influence of different factors on the precision of the NMR measurements is discussed. Some proposals are given for MAS experiments used with solid‐state samples. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 184–193, 2007.
Generalized treatment of NMR spectra for rapid chemical reactions
Authors: Christianson Matthew D. , Landis Clark R.
Published: July 2007

Application of NMR spectroscopy to fast irreversible reactions (t1/2 < 0.7 s) has been hampered by limitations in instrumentation and general methods for modeling the complicated spectra that result. Analytical descriptions of nuclear spin dynamics during fast reactions, first solved by Ernst and coworkers, are limited to first‐order reaction kinetics. We demonstrate that numeric methods enable simulation of NMR spectra for fast reactions having any form of rate law. Simulated stopped‐flow NMR spectra are presented for a variety of common kinetic scenarios including reversible and irreversible reactions of first and second‐order, multistep reactions, and catalytic transformations. The simulations demonstrate that a wealth of mechanistic information, including reaction rates, rate laws, and the existence of intermediates, is imbedded in a single NMR spectrum. The sensitivity of modern NMR instrumentation along with robust methods for simulating and fitting kinetic parameters of fast reactions make stopped‐flow NMR an attractive method for kinetic studies of fast chemical reactions. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 165–183, 2007.
An MRI‐dedicated parallel FDTD scheme
Authors: Wang Hua , Trakic Adnan , Xia Ling , Liu Feng , Crozier Stuart
Published: July 2007

This study extends our recent works on object‐oriented Finite‐Difference Time‐Domain (FDTD) simulations into a parallel‐computing framework, producing substantially improved performance with respect to computing time efficiency. The simulator is intended to be a complete, high‐performance FDTD model of an MRI system including all temporal radio frequency (RF) and low‐frequency field generating units and electrical models of the patient. The parallel computational structure has been designed using a Message‐Passing Interface (MPI) Library. The implementation of the MRI‐dedicated FDTD algorithms within the parallel computing framework is detailed. To improve the simulator performance in a realistic network‐computing environment, several software design aspects have been investigated. These include: data transmission with consideration of buffered and synchronous communication, load balancing on the computing network using a weighting mechanism. The power of the optimized FDTD parallel architecture is illustrated by two distinct, large‐scale field calculation problems involving the study of the interaction of RF‐fields with human tissue (whole‐body, male and female) in high field MRI and characterization of the temporal eddy currents induced on the cryostat vessel during gradient switching. The examples demonstrate the improved capabilities of the simulator. In addition, through the parallelization of the FDTD algorithm we are in a position to study various MRI phenomena at much higher spatial resolutions than was previously feasible. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 31B: 147–161, 2007
InterGrid: a case for internetworking islands of Grids
Authors: Dias de Assunção Marcos , Buyya Rajkumar , Venugopal Srikumar
Published: July 2007

Over the last few years, several nations around the world have set up Grids to share resources such as computers, data, and instruments to enable collaborative science, engineering, and business applications. These Grids follow a restricted organizational model wherein a Virtual Organization (VO) is created for a specific collaboration and all interactions such as resource sharing are limited to within the VO. Therefore, dispersed Grid initiatives have led to the creation of disparate Grids with little or no interaction between them. In this paper, we propose a model that: (a) promotes interlinking of islands of Grids through peering arrangements to enable InterGrid resource sharing; (b) provides a scalable structure for Grids that allow them to interconnect with one another and grow in a sustainable way; (c) creates a global Cyberinfrastructure to support e‐Science and e‐Business applications. This work identifies and proposes architecture, mechanisms, and policies that allow the internetworking of Grids and allows Grids to grow in a similar manner as the Internet. We term the structure resulting from such internetworking between Grids as theInterGrid. The proposed InterGrid architecture is composed of InterGrid Gateways responsible for managing peering arrangements between Grids. We discuss the main components of the architecture and present a research agenda to enable the InterGrid vision. Copyright © 2007 John Wiley & Sons, Ltd.
Broadband ISDN — service visions and technological realities
Authors: Spears Dan R.
Published: July 2007

Two forces, service needs and technological advances, are driving the extension of the Integrated Services Digital Network (ISDN) into the broadband area. First, this paper identifies several business and residential services which provide a market pull for broadband ISDN (BISDN). Secondly, it reviews recent advances in optical transmission and broadband switching which provide a technological push. Finally, it describes an experimental broadband prototype constructed to help us better understand the transmission, switching, signaling protocol, software, and service capabilities required for BISDN.
Home automation: A view from a marketer
Authors: Parks Patricia H.
Published: July 2007

Home automation is a new, exciting industry that will change many of our products and habits in the 21st century. It is also complex, and there are many more questions today than answers. This article addresses the basic questions ‘What is home automation?’, ‘Who cares?’ and ‘What basic issues require resolution to foster this industry's growth?’
Video coding in bisdn with a distribution rate of approximately 135 mb/s
Authors: Rzeszewski T. S.
Published: July 2007

Video coding for Broadband Integrated Services Digital Network (BISDN) is analysed, and coding techniques that use sub‐Nyquist sampling are proposed. Specifically, recommendations are given for digital video coding for EQTV distribution in the area of BISDN at a payload rate of approximately 135 Mb/s. The contribution signal that is used in video production will either be the CCIR Recommendation 601 signal or a minor modification of it to maximize horizontal resolution. Also, the scanning parameters will be the same as NTSC so that the same monitor can be used to display either EQTV or NTSC TV.

A compatible vertical improvement can be added initially, or in the future, that will provide additional vertical resolution beyond the capability of the present NTSC TV, or the capabilities of Recommendation 601. Finally, several coding techniques for video distribution are configured to maximize horizontal resolution given the above constraints. Two of these video coding techniques allow extra bandwidth by using sub‐Nyquist sampling techniques together with comb filtering. This EQTV system will produce a horizontal resolution that is close to values normally used for HDTV.
1‐persistent DUAL channel local area network for integrated voice and data application
Authors: Vaman Dhadesugoor R. , Wu Chin Tu , Lu Kal
Published: July 2007

It is a well‐known fact that the carrier sense multiple access with collission detection (CSMA/CD) protocol would suffer from throughput degradations and long packet delays at heavy loads due to excessive collisions and retransmissions, and thus is not suitable for voice/data integration. Recently, a new protocol called carrier sense multiple access with time‐split collision detection and split channel reservation (CSMA‐TCD‐SCR) has been proposed1 to improve the channel throughput of CSMA/CD protocol by splitting the common channel into dual channels, i.e. one for data transfer and the other for reservation. It has been shown that the CSMA‐TCD‐SCR protocol improves the channel throughput and stability performance significantly.1 In this paper, we propose a 1‐persistent dual‐channel LAN (1P‐DC‐LAN) protocol with the tree algorithm for reservation, which is an extension of the CSMA‐TCD‐SCR protocol, for voice/data integration applications. Through approximate analytical modelling and computer simulations, it has been demonstrated that the 1P‐DC‐LAN protocol exhibits nearperfect scheduling throughputs for data transmission and highly bounded voice packet delays. In addition, the results were compared with IEEE 802.3 CSMA/CD and twin‐channel CSMA/CD.
Network control: The other gating factor for network evolution to broadband
Authors: Beckner Mark
Published: July 2007

An invited contribution from a member of the editorial board, or another respected figure in the profession, in which a particular viewpoint is put forward giving an informed, but not necessarily conventional, opinion on a major topic in the field of communication systems..
Cost analysis for switched star broadband access
Authors: Lu K. W. , Wolff R. S.
Published: July 2007

This paper presents a first cost analysis of a broadband local access system based on the switched star architecture. The per‐subscriber cost, including all network components from the customer premises interface to the central office switch termination, is established. Both near‐term and long‐range per‐subscriber costs based on technology trend forecasts are obtained and serve as a bench‐mark. These results are used for comparisons of the relative costs of offering different broadband access capabilities. The analysis identifies the most important elements in the per‐subscriber cost and explores trade‐offs and possibilities for cost reduction.
Passive optical networks for local telephony and cable TV provision
Authors: Faulkner D. W. , Ballance J. W.
Published: July 2007

Recent proposals have been made for a passive optical local access network (PON) for telephony and cable TV applications. These are leading to the design of new telecommunications customer access equipment whose functional requirements are discussed, together with details of the system demonstrators at BTRL. Possible sccenarios for network deployment are presented.
Technical concepts in broadband ATM
Authors: Beau Olivier , Paul Jean‐Lin , Penet Xavier
Published: July 2007

The asynchronous transfer mode (ATM) approach to connecting subscribers to the broadband packet network, is expected to bring an appropriate solution for a future public network. The prerequisites of the broadband network, the characteristics of the ATM technique as well as possible ATM network equipment are described here. Envisaged solutions to the basic problems being posed are discussed.
ATM: A contribution to the debate on broadband ISDN
Authors: Coudreuse Jean‐Pierre
Published: July 2007

The definition of broadband ISDN recently became a major topic of research and predevelopments. Fast packet technologies are widely recognized as the basis for BISDN. Even if international consensus has appeared far more quickly than could have been expected a few years ago, a lot of issues remain open. This paper is a contribution to discussions on some important topics relating to the definition of asynchronous transfer mode.
Considerations on ATM switching techniques
Authors: Lutz K. A.
Published: July 2007

A comparison of various ATM switching matrix principles using an input buffer, output buffer or central buffer bearing in mind system aspects, traffic aspects and technological aspects comes out clearly in favour of the last‐named. When larger switching networks are set up, consisting of 16/16 or 32/32 switching elements, the compromise proposal arrived at if various assessment criteria are used indicates a preference for two‐stage folded networks made up of interconnections of 16/16, 32/32 or 64/64 modules, depending on the desired maximum capacity. Three‐stage folded networks are only advantageous for switching networks with over 2000 access lines.
Videotex and interactive services on tree‐and‐branch cable TV networks
Authors: Roberts S. C.
Published: July 2007

Interactive services on tree‐and‐branch cable TV systems in the U.K. have been rather slow to emerge. This has been partly due to the high cost of the customers' terminals but is also due to the difficulty of passing keyboard data, from the customers, back over the cable network to the head‐end. This paper describes a new approach to these problems and shows that Videotex and other interactive services can be provided without major engineering changes to the network.
Israel's cable TV and pay TV — on the way to becoming a reality
Authors: Bines Rozalia
Published: July 2007

Israel's cable TV plans are among the most comprehensive of any country. This paper reviews the progress to date, and details the technical specifications and administrative co‐ordination involved in such a major enterprise.
Can purchasing power parity help forecast the dollar?
Authors: Cochran Steven J. , Defina Robert H.
Published: July 2007

This paper examines the information on future exchange rate movements provided by the doctrine of purchasing power parity (PPP). Previous research has studied this issue by analyzing the time‐series properties of period‐by‐period levels of, or changes in, exchange rates. In contrast, the present study focuses on the durations of periods in which exchange rates deviate from their PPP levels. If PPP provides information about future exchange rate movements, these durations should exhibit positive duration dependence. That is, the probability of returning to PPP levels should increase as the period of deviation increases. Parametric hazard functions estimated using data from eighteen countries provide no evidence of positive duration dependence. These results are robust to alternative definitions of PPP and to alternative functional specifications. While exchange rates take prolonged swings away from their PPP levels and then eventually return, these movements apparently constitute Monte Carlo cycles in which, at any point in time, the probability of moving back toward PPP is the same as the probability of moving farther away. Thus, PPP provides no useful information on future exchange rate changes, a result consistent with market efficiency.
Lead‐lag relationship between spot index and futures price of the nikkei stock average
Authors: Tse Y. K.
Published: July 2007

This paper examines the lead‐lag relationship between the spot index and futures price of the Nikkei Stock Average. Using daily data in the post‐crash period we investigate the interaction between the spot and futures series through the error correction model. Two versions of error correction models are considered, depending on the postulated long‐run equilibrium relationship. It is found that lagged changes in the futures price affect the short‐term adjustment in the spot index, but not vice versa. Forecasting models for the spot index are also constructed using the univariate time series approach and the vector autoregressive method. For the post‐sample forecast comparison the error correction models produce the best results. The vector autoregressive method performs better than the martingale model, while the univariate time series method gives the poorest forecasts.
Als die Menschen sesshaft wurden
Authors: Schmidt Klaus
Published: July 2007

Wege zur frühen Menschheitsgeschichte: Am Göbekli Tepe in Anatolien legen Archäologen einzigartige steinzeitliche Monumente frei. Sie tragen zu einem neuen Verständnis der Siedlungsgeschichte und des beginnenden Ackerbaus bei
„Zwei Herzen schlagen ach' in meiner Brust”︁
Authors: Unterstell Rembert
Published: July 2007

Der Leipziger Herzchirurg Torsten Doenst verbindet seine klinische Arbeit mit wegweisender Grundlagenforschung
Candidate glioblastoma development gene identification using concordance between copy number abnormalities and gene expression level changes
Authors: Lo Ken C. , Rossi Michael R. , LaDuca Jeffrey , Hicks David G. , Turpaz Yaron , Hawthorn Lesleyann , Cowell John K.
Published: July 2007

Copy number abnormalities (CNAs) in tumor cells are presumed to affect expression levels of genes located in region of abnormality. To investigate this relationship we have surveyed the losses, gains and amplifications in 30 glioblastomas using array comparative genome hybridization and compared these data with gene expression changes in the same tumors using the Affymetrix U133Plus2.0 oligonucleotide arrays. The two datasets were overlaid using our in‐house overlay tool which highlights concordance between CNAs and expression level changes for the same tumors. In this survey we have highlighted genes frequently overexpressed in amplified regions on chromosomes 1, 4, 11, and 12 and have identified novel amplicons on these chromosomes. Deletions of specific regions on chromosomes 9, 10, 11, 14, and 15 have also been correlated with reduced gene expression in the regions of minimal overlap. In addition we describe a novel approach for comparing gene expression levels between tumors based on the presence or absence of chromosome CNAs. This genome wide screen provides an efficient and comprehensive survey of genes which potentially serve as the drivers for the CNAs in GBM. © 2007 Wiley‐Liss, Inc.
Does the quality of care in Medicaid MCOs vary with the form of physician compensation?
Authors: Quast Troy , Sappington David E. M. , Shenkman Elizabeth
Published: July 2007

A growing fraction of Medicaid participants are enrolled in managed care organizations (MCOs). MCOs contract with primary care physicians (PCPs) to provide health‐care services to Medicaid enrollees. The PCPs are generally compensated either via fee‐for‐service (FFS) or via capitated arrangements. This paper investigates whether the quality of care that Medicaid enrollees receive varies with the means by which PCPs are compensated. Using data for all Medicaid MCO enrollees in a large state, we find that enrollees in MCOs that pay their PCPs exclusively via FFS arrangements are more likely to receive services for which the PCPs receive additional compensation. These enrollees also are less likely to receive services for which the PCPs do not receive additional compensation. These findings suggest that financial incentives may influence the behavior of PCPs in Medicaid MCOs, and thus the quality of the health care received by Medicaid participants enrolled in MCOs. Copyright © 2007 John Wiley & Sons, Ltd.
Antibody responses to survivin and their clinical significance in patients with head and neck cancer
Authors: Eto Mayumi , Kodama Satoru , Uemura Naoki , Suzuki Masashi
Published: July 2007

Background.

Survivin is highly expressed in cancer cells but shows little or no expression in normal tissues. Little is known about antibody responses to survivin in patients with head and neck cancer.

Methods.

Anti‐survivin antibody responses in patients with head and neck cancer were investigated by enzyme‐linked immunosorbent assay. Anti‐p53 antibody and squamous cell carcinoma antigen were also examined.

Results.

Sera from 69 of 97 patients (71.1%) were positive for anti‐survivin, with a cutoff value (absorbance; >0.673) with healthy control subjects. High levels of anti‐survivin were detected in patients with advanced stage. Interestingly, levels of anti‐survivin fell after curative treatment. In addition, 24 of 26 (92.3%) tested patients were positive for at least 1 of 3 markers.

Conclusions.

These findings suggest that survivin may act as a major cancer antigen in head and neck cancer. Anti‐survivin antibody responses may be a valuable marker in patients with head and neck cancer. © 2007 Wiley Periodicals, Inc. Head Neck 2007