bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil adsorption defluoridation of drinking water for an Ethiopian rural community
Authors: Errico M. , Desogus F. , Mascia M. , Tola G. , Dendena L.
Published: October 2006

Content of fluoride compounds in some typical Ethiopian water sources was analysed and several commonly available soils were characterized for their adsorption properties regarding the water defluoridation. Various soils were collected in different Ethiopian sites and the samples were analysed by X-ray diffractometry for their mineralogical composition. Batch experimental runs at room temperature were performed to evaluate the adsorption capacity of each soil sample as well as to deduce the adsorption isotherms of fluoride ions with respect to the examined soils. The best soil was identified in terms of adsorption capacity and considered for the design of two different adsorption apparatuses. Considering the water consumption of a small rural community, the capacity of the adsorption unit was selected to assure a reduction of the fluoride concentration in drinking water to the limits recommended by the World Health Organization and to allow a suitable working time of the adsorption unit before the replacement of adsorbent would be necessary.
Synthesis and separation properties for Cu(II)‐Ni(II) of macroporous crosslinked polystyrene‐supported triethylenetetramine resin using Cu(II) as template
Authors: Sun Changmei , Qu Rongjun , Sun Xiangrong , Ji Chunnuan , Wang Chunhua
Published: October 2006

A new method for preparing a novel macroporous chelating resin that has good adsorption capability for Cu(II) and high selectivity for it with the coexistence of Ni(II) was introduced in this article. First, the aminated resin (PS‐TETA) was synthesized by the reaction of crosslinked macroporous chloromethylated polystyrene with triethylenetetramine. Subsequently, PS‐TETA was coordinated with Cu(II) and then PS‐TETA‐Cu was obtained. After the crosslinking reaction of PS‐TETA‐Cu with epoxy chloropropane, the adsorbed Cu(II) was removed by chlorhydric acid, and then the target resin‐Cu(II) template triethylenetetramine crosslinked polystyrene resin was obtained. The selectively sorption tests for Cu(II) showed that the sorption capacity was as high as 1.6 mmol/g and the selectivity coefficient αCu(II)/Ni(II) could reach to 9.06 with the coexistence of Ni(II). SEM and nitrogen adsorption at 77 K methods were used to characterize the porous structure of the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 963–967, 2007
Physical properties and morphology of polycaprolactone/starch/pine‐leaf composites
Authors: Kim Eung Gu , Kim Beom Soo , Kim Dae Su
Published: October 2006

Polycaprolactone (PCL)/starch and PCL/starch/pine‐leaf composites, which can be possibly applied as biodegradable food packaging materials with natural pine flavor, were prepared and characterized in this study. The effect of incorporating a silane coupling agent at different content levels on the physical properties and morphology of the composites was studied. To investigate the melting behavior of the composites, a differential scanning calorimetry was employed. A universal testing machine was used to investigate the tensile properties of the composites and the water absorption properties of the composites were also investigated. Scanning electron microscope was used to investigate the morphology of the composites. The physical properties and morphology of the PCL/starch and PCL/starch/pine‐leaf composites were largely affected by the composition, especially the content of the silane coupling agent. The silane coupling agent led to a much better interfacial compatibility between the PCL matrix and the fillers and resulted in better physical properties of the composites. The PCL/starch/pine‐leaf composite with the silane coupling agent showed a morphology, indicating a good interfacial adhesion between the PCL matrix and the fillers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 928–934, 2007
Effect of annealing on the structure and properties of polyvinylidene fluoride hollow fiber by melt‐spinning
Authors: Li Xianfeng , Lu Xiaolong
Published: October 2006

Polyvinylidene fluoride hollow fibers were prepared by melt‐spinning technique under three spinning temperatures. The effects of annealing treatment on the structure and properties of hollow fiber were studied by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), tensile test, and scanning electron microscopy (SEM) measurements. DSC and WAXD results indicated that the annealing not only produced secondary crystallization but also perfected primary crystallization, and spinning and annealing temperature influenced the crystallinity of hollow fiber: the crystallinity decreased with the increase of spinning temperature; 140°C annealing increased the crystallinity, and hardly influenced the orientation of hollow fiber; above 150°C annealing increased the crystallinity as well, and furthermore had a comparative effect on the orientation. The tensile tests showed that the annealed samples, which did not present the obvious yield point, exhibited characteristics of hard elasticity, and all the hollow fiber had no neck phenomenon. Compared with the annealed sample, the precursor presented a clear yield point. In addition, the annealed samples had a higher break strength and initial modulus by contrast with the precursor, and the 140°C annealed sample showed the smallest break elongation. SEM demonstrated the micro‐fiber structure appeared in surface of drawn sample. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 935–941, 2007
Effect of molecular structures on polyimide properties: Comparison between estimations and experiments
Authors: Xu Yexin , Chen Cuixian , Zhang Pengxia , Sun Benhui , Li Jiding
Published: October 2006

The density and glass transition temperature (Tg) of 11 polyimides were investigated by experiments and predictions using the connectivity indices method to explore the structure–property relationships. The predicted results are in good agreement with the experimental data. The mean interchain spacings (d‐spacings) of polyimides increase with the introduction of bridging groups, i.e., following the order: PDA < BZD < ODA < MDA < BDAF, while the densities increase in the order of MDA < BZD < PDA, and cohesive energy densities (CEDs) of polyimides change following the order of BDAF < MDA < ODA < BZD < PDA. In addition, the glass transition temperatures (Tg's) increase as the CEDs increase for the polyimides prepared from the same dianhydride and different diamines, whereas no certain correlation exists between Tg's and the values of the characteristic ratio (C∞). This indicates that the strength of interchain interaction influences the Tg's of polyimides much stronger than the chain flexibility. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 998–1003, 2007
A novel and facile method for the synthesis of octa(aminophenyl)silsesquioxane and its nanocomposites with bismaleimide‐diamine resin
Authors: Zhang Jun , Xu Ri‐Wei , Yu Ding‐Sheng
Published: October 2006

Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octa(nitrophenyl)silsesquioxane (ONPS) by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent with a yield of around 86%. The product was characterized by FTIR, GPC, 1H NMR, 29Si NMR, and XRD. It was found that the time period for preparation of ONPS from octaphenylsilsesquioxane could be considerably shortened, reaching the complete nitration and avoiding double nitration of the aromatic rings. The polyimides were prepared by the reaction of N,N′‐bismaleimido‐4,4′‐diphenylmethane with OAPS and 4,4′‐diamino‐diphenyl ether. The structure of resulting organic–inorganic hybrid nanocomposites was characterized by XRD and FTIR. The decomposition temperature and char yield of resulting materials increased with increasing OAPS loading. The DSC data showed that the glass transition temperature of nanocomposite was enhanced by 36°C with the content of OAPS around 15 wt %. As the feed amount of OAPS increased further, the decrease in Tg's could be observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1004–1010, 2007
Electric conductivity of PS/PA6/carbon black composites
Authors: Xu Zhongbin , Zhao Chao , Gu Aijuan , Fang Zhengping
Published: October 2006

Polystyrene (PS)/nylon6 (PA6)/carbon black (CB) composites were prepared in Haake rheometer. The factors influencing the electric conductivity of PS/PA6/CB composites were investigated. Results showed that CB particles only distribute in PA6 phase because of the strong polarity of PA6. The CB content in PA6 phase and the morphology of PA6/CB phase affect the electric conductivity of PS/PA6/CB composites. No matter the PA6/CB phase is continuous or dispersed, the electric conductivity of PS/PA6/CB composites increases with the increase of CB content in the PA6 phase; higher continuous degree of PA6/CB phase leads to higher electric conductivity. A new term, statistical average critical distance (SACD), was defined to explain the electric mechanism of PS/PA6/CB composites, which is a function of CB content in PA6. The SACD of PS/PA6/CB composites, in which CB content is 23 wt % in PA6, was quantitatively counted, which is about 54 nm. Keeping the CB content in composites at 5.67 wt %, the optimum mass ratio of PS/PA6 for the composites having the highest electric conductivity is 80 : 20, resulting from the competitive result of the earlier two factors (that is the CB content in PA6 phase and the morphology of PA6/CB phase). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1042–1047, 2007
Extraocular eye muscles in human fetuses with craniofacial malformations: Anatomical findings and clinical relevance
Authors: Plock J. , Contaldo C. , Von Lüdinghausen M.
Published: October 2006

Anomalies of the extraocular muscles have been suspected to be present frequently in patients with craniofacial malformations. We studied the extraocular musculature in the orbits of 15 anencephalic human fetuses between the 5th and 10th months after gestation, and in one fetus with an occipital meningocele and a large defect of the left cranial base. The findings were compared to those in nine normal age‐matched fetuses. All malformed fetuses exhibited special features of the levator palpebrae superioris muscle, either its absence, an anomaly of the muscle belly, or an anomalous insertion. In addition, deficient or aberrant muscle bellies of the oblique and rectus muscles were found. In anencephaly, the frontal bone is condensed, forming narrowed orbital cavities with hypotelorism. Frequent disturbance of extraocular muscle development in fetuses with craniofacial malformations is implicated. The presented specimens are examples of extreme variants of cranial and craniofacial malformation syndromes. Thus, similar findings of extraocular muscles might also be regularly found in clinically relevant craniofacial malformations. This would force new considerations about diagnostic and therapeutic approaches to patients with craniofacial malformations. Clin. Anat. 20:239–245, 2007. © 2006 Wiley‐Liss, Inc.
Thermische Verfahren: Methoden und Kinetik der Keimreduktion und ‐inaktivierung in Lebensmitteln
Authors: Kulozik U.
Published: October 2006

Primäre Ursache für den Verderb von Lebensmitteln sind Mikroorganismen, die über Rohmaterialien oder über Kontaminationen im Verlauf des Herstellprozesses in das Produkt gelangen. Der Beitrag informiert über die Methoden zur Keiminaktivierung beim thermischen Behandeln von Lebensmitteln. Je nach Intensität der thermischen Behandlung werden die in einem Produkt enthaltenen Mikroorganismen vollständig oder teilweise abgetötet. Abnormale Inaktivierungskinetiken werden im Vergleich zum loglinearen Inaktivierungsverlauf beschrieben. Abschließend werden Verfahren zur Erfassung von Produktveränderungen im Zusammenhang mit dem gesamten Zeit‐Temperatur‐Profil dargestellt.
Chemische Verfahren zur Reinigung und Sterilisation von Aseptikanlagen
Authors: Wildbrett G.
Published: October 2006

Fachgerechte Reinigung und Sterilisation soll Aseptikanlagen nach jedem Gebrauch wieder in den erforderlichen hohen Hygienezustand versetzen. Der Beitrag geht auf die in Aseptikanlagen der Lebensmittelindustrie zu erwartenden Verschmutzungen sowie die Zusammensetzung und Wirkungsweise von Reinigungs‐ und Desinfektionsmitteln ein, die in Aseptikanlagen gebräuchlich sind. Ferner werden Verfahrensweisen, die dafür benötigten technischen Einrichtungen, Möglichkeiten der Erfolgskontrolle der Hygienemaßnahmen und die Regeneration von Reinigungslösungen nach ihrem Gebrauch vorgestellt.
UV‐Inaktivierung von Viren und Bakterien mit einem innovativen Wendelrohrreaktor im Labor‐ und Prozessmaßstab
Authors: Schmidt S. , Kauling J.
Published: October 2006

In biotechnologischen und pharmazeutischen Prozessen ist die Vermeidung und Eliminierung viraler Kontaminationen von entscheidender Bedeutung. Der neuartige Wendelrohrreaktor UVivatec wurde für die Bestrahlung trüber flüssiger Medien mit UV konzipiert. Er inaktiviert sehr effektiv besonders kritische Viren, ohne dass hohe Produktverluste in Kauf genommen werden müssen. Die Methode ergänzt in idealer Weise bestehende und etablierte Verfahren.
Efficient Total Synthesis of (–)‐(3S,6R)‐3,6‐Dihydroxy‐10‐methylundecanoic Acid
Authors: Kumar Pandey Satyendra , Kumar Pradeep
Published: October 2006

An efficient enantioselective synthesis of (–)‐(3S,6R)‐3,6‐dihydroxy‐10‐methylundecanoic acid (1) from epichlorohydrin is described. The key steps include Jacobsen’s HKR, Sharpless asymmetric dihydroxylation, regioselective opening of epoxide and cyclic sulfate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Decreasing incidence of cervical adenocarcinoma in Ontario: Is this related to improved endocervical Pap test sampling?
Authors: Howlett Roberta I. , Marrett Loraine D. , Innes Michael K. , Rosen Barry P. , McLachlin C. Meg
Published: October 2006

In many developed countries, the incidence of cervical cancer has decreased. These reductions have been specific to squamous cell carcinoma (SCC) and have not included adenocarcinoma (AC). Incidence of AC has increased steadily over the last 20 years. The intent of this article is to examine trends in cervical adenocarcinoma incidence in Ontario over a 20‐year period in relation to screening practices. All cases of cervical cancer between 1981 and 2002 were extracted from the Ontario Cancer Registry (a population‐based, provincial‐wide database). Age‐standardized incidence rates were calculated overall, by broad age groups and by morphological type (SCC and AC). Time trends were assessed using JoinPoint methodology. In Ontario, opportunistic cervical cancer screening has been accompanied by significantly decreased rates of SCC since at least 1981. Conversely, the incidence of AC rose by 3.1% per year (95% CI: 1.6%, 4.6%) between 1981 and 1995, and subsequently declined by 4.0% per year (95% CI: −7.4%, −0.5%). From the mid‐ to late‐1990s, instructions were distributed to clinicians, reinforcing the importance of dual specimen collection (i.e., using both spatula and endocervical brush). At the same time, laboratories routinely provided physicians with kits that included both spatula and brush. The subsequent decline in AC incidence may be due, in part, to improved specimen collection. As well, the decline may be partly due to increased awareness of AC precursors among cytopathologists and clinicians, and/or improvements in laboratory training and quality assurance. © 2006 Wiley‐Liss, Inc.
Degradation of porous poly(D,L‐lactic‐co‐glycolic acid) films based on water diffusion
Authors: Huang Ying‐Ying , Qi Min , Liu Hong‐Ze , Zhao Hong , Yang Da‐Zhi
Published: October 2006

Poly(D,L‐lactic‐co‐glycolic acid) has been extensively used as a controlled release carrier for drug delivery due to its good biocompatibility, biodegradability, and mechanical strength. Effects of dense and porous film's degradation behavior have been systematically investigated up to 17 weeks in Hank's Simulated Body Fluid at 37°C. The degradation of the films was studied by measuring changes in weight, molecular weight and its distribution, morphology, composition etc.. A special thing was that the differences in water diffusion in dense and porous structure films caused the different degradation behavior. According to the characteristic changes of various properties of films, the degradation process is suggested to be roughly divided into four stages, tentatively named as water absorption stage, dramatic loss of molecular weight or micro‐pores formed stage, loss of weight or enlarged‐pores formed stage, pores diminished or pores collapse stage. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Weak amicable T‐matrices and Plotkin arrays
Authors: Holzmann W. H. , Kharaghani H.
Published: October 2006

We introduce the class of weak amicable T‐matrices and use it to construct a class of orthogonal designs,

for p = 1 and for p a prime power ≡ 3 (mod 4), and all odd q, q ≤ 21. This class includes new Plotkin arrays of order 24, 40, 56 and for the first time, of orders 8q, q ∈ {9,11,13,15,17,19,21}. © 2006 Wiley Periodicals, Inc. J Combin Designs 16: 44–52, 2008
On large sets of almost Hamilton cycle decompositions
Authors: Zhao Hongtao , Kang Qingde
Published: October 2006

A large set of CS(v, k, λ), k‐cycle system of order v with index λ, is a partition of all k‐cycles of Kv into CS(v, k, λ)s, denoted by LCS(v, k, λ). A (v − 1)‐cycle is called almost Hamilton. The completion of the existence spectrum for LCS(v, v − 1, λ) only depends on one case: all v ≥ 4 for λ = 2. In this article, it is shown that there exists an LCS(v, v − 1,2) for any v ≡ 0,1 (mod 4) except v = 5, and for v = 6,7,10,11. © 2006 Wiley Periodicals, Inc. J Combin Designs 16: 53–69, 2008
Gene therapy. An ethical profile of a new medical territory
Authors: Fuchs Michael
Published: October 2006

From early on, the possibility of genetic intervention in humans has been the subject of philosophical and ethical reflection in the scientific community. It became the object of public debate and parliamentary decision‐making under the rule of law even before the first authorized trials on human subjects could start. This article explains why the debate on germ‐line intervention and genetic enhancement is still ongoing. The focus is on somatic gene therapy. There is a political and academic consensus that it represents an adequate tool for a high‐ranking end if some points are considered and taken into account. But where do we stand and what are the ethical conclusions we can draw from recent clinical experiences? Copyright © 2006 John Wiley & Sons, Ltd.
Maximum directed cuts in acyclic digraphs
Authors: Alon Noga , Bollobás Béla , Gyárfás András , Lehel Jenő , Scott Alex
Published: October 2006

It is easily shown that every digraph with m edges has a directed cut of size at least m/4, and that 1/4 cannot be replaced by any larger constant. We investigate the size of the largest directed cut in acyclic digraphs, and prove a number of related results concerning cuts in digraphs and acyclic digraphs. © 2006 Wiley Periodicals, Inc. J Graph Theory 55: 1–13, 2007
Kinetics of thermal gas‐phase decomposition of 2‐bromopropene using static system
Authors: Nisar Jan , Awan Iftikhar A.
Published: October 2006

The gas phase elimination kinetics of 2‐bromopropene was studied over the temperature range of 571–654 K and pressure range of 12–46 Torr using the seasoned static reaction system. Propyne was the only olefinic product formed and accounted for >98% of the reaction. This product was formed by homogeneous, unimolecular pathways with high‐pressure first‐order rate constant k∞ given by the equation k∞ = 1013.47 ± 0.6 exp−208.2 ± 6.7 (kJ mol−1)/RT. The error limits are 95% certainty limits. The observed Arrhenius parameters are consistent with the four centered activated complex. The presence of methyl group on α‐carbon lowers the activation energy by 41 kJ mol−1. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 1–5, 2007
Carbon nanotube–polybithiophene photovoltaic devices with high open‐circuit voltage
Authors: Patyk Rodolfo L. , Lomba Bruno S. , Nogueira Ana Flávia , Furtado Clascídia A. , Santos Adelina Pinheiro , Mello Regina M. Q. , Micaroni Liliana , Hümmelgen Ivo A.
Published: October 2006

We report the preparation of photovoltaic devices using modified single wall carbon nanotubes, SWNTs. Devices are produced stacking on top of fluorine‐doped tin‐oxide, an electrochemically deposited polybithiophene layer, a layer of SWNT blended with poly(3‐octylthiophene) and an evaporated top metal contact, Ca/Al or Al. Ca/Al‐top‐electrode devices achieve open‐circuit voltages of 1.81 V and average power conversion efficiency of 1.48% at irradiance of 15.5 W m–2, spectrally distributed following AM1.5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of ovenproof plastic films on the quality of spotted rose snapper (lutjanus guttatus) fillets during frozen storage
Authors: Dorado‐Rodelo José Angel , Ezquerra‐Brauer Josafat Marina , Soto‐Valdez Herlinda
Published: October 2006

Spotted rose snapper (Lutjanus guttatus) fillets packed in two polymer films, polyamide 6,6 (PA66) and polyethylene terephthalate (PET), were stored at −20°C for a period of 120 days. Films were tested for melting temperature (PA66 253–257°C and PET 252–255°C), oxygen transmission rate [PA66 51.8 ± 12.9cm3/(m2·24h·atm) and PET 152.7 ± 0.2cm3/(m2·24h·atm)] and water vapor transmission rate [PA66 17.8 ± 1.7g/(m2·24h) and PET 6.5 ± 0.2g/(m2·24h)]. Sensory analyses (firmness, flavour and appearance) were performed at 0, 30, 60, 90 and 120 days of storage after baking the fillets in the same storage bags. For raw fillets, their water‐holding capacity (WHC), total aerobic counts (TAC), pH, trimethylamine (TMA) and shear‐force resistance were measured at the same periods. Sensory analyses after baking showed no differences between the fillets packaged in the two films. The WHC, TAC, pH and TMA values in both products were kept within accepted limits. The fillets packed in PET showed a significant increase in firmness (shear‐force resistance) during the first 60 days of storage and then a decrease at 90 days due to dehydration through the film seals. Over the same period, the fillets packed in PA66 showed no significant changes in firmness. In this study, it was demonstrated that it is possible to develop a ready‐to‐bake fish fillet product by using ovenproof films for packaging during storage. Copyright © 2006 John Wiley & Sons, Ltd.
Reactivation pathway of the hydrogenase H‐cluster: Density functional theory study
Authors: Motiu Stefan , Dogaru Daniela , Gogonea Valentin
Published: October 2006

This work puts forth a reaction pathway for the reactivation of exogenous ligand inhibited H‐cluster, the active site of Fe‐only hydrogenases. The H‐cluster is a dimetal complex, Fe–Fe, with the metal centers bridged by di(thiomethyl)amine. Exogenous ligands, H2O, and OH−, are bound to the distal iron (Fed). Density functional theory (DFT) calculations on the native and ruthenium‐modified H‐cluster have been performed using the B3LYP functional with 6‐31+G** and 6‐311+G** basis sets. We have ascertained that there is a thermodynamically favorable pathway for the reactivation of the OH− inhibited H‐cluster, which proceeds by an initial protonation of the Fed–OH− complex. The proposed reaction pathway has all its intermediate reactions ensue exothermically. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Growing One‐Dimensional Metallic Nanowires by Dielectrophoresis
Authors: Ranjan Nitesh , Vinzelberg Hartmut , Mertig Michael
Published: October 2006

We report an electrical‐field‐controlled growth process for the directed bottom‐up assembly of one‐dimensional palladium nanowires between microfabricated electrodes. The wires, grown from an aqueous palladium salt solution by dielectrophoresis, have a thickness of only 5–10 nm and a length of up to several micrometers. The growth process depends largely on both the strength of the applied ac field and the concentration of the metal salt solution. The conditions for optimum growth are evaluated. Room‐temperature current–voltage measurements show ohmic behavior and indicate electromigration effects at higher voltages. Low‐temperature transport measurements reveal localization effects with a characteristic resistance minimum at 20 K. The temperature dependence below the minimum shows the wires to be one dimensional in their electron‐transport properties. The investigated growth method is capable of building complex circuit patterns for future nanoelectronics.
On the ‘Meishan Phenomenon’ in Song culture
Authors: Shangshu Zhu
Published: October 2006

The Song Dynasty enjoyed a splendid culture. Meishan, a small county in Southwest Sichuan, was one of the most developed cultural areas. This is closely related to a large-scale immigration after the collapse of the Tang Dynasty and the ‘Jingkang defeat’ in the Song Dynasty. Meishan was an area receiving more immigrants than other regions. A great number of distinguished families from North China brought with them the advanced culture of the Yellow River areas to Meishan, which combined with native culture, and produced many “cultural clans” from this “clan culture.” Some of these people became elites in various areas through education and the Civil Service Examinations. The so-called “Meishan Phenomenon” was a result of cultural melting.
A model of tenascin‐X integration within the collagenous network
Authors: Lethias Claire , Carisey Alexandre , Comte Jane , Cluzel Caroline , Exposito Jean-Yves
Published: October 2006

Tenascin‐X is an extracellular matrix protein whose absence leads to an Ehlers‐Danlos syndrome in humans, characterized mainly by disorganisation of collagen and elastic fibril networks. After producing recombinant full‐length tenascin‐X in mammalian cells, we find that this protein assembled into disulfide‐linked oligomers. Trimers were the predominant form observed using rotary shadowing. By solid phase interaction studies, we demonstrate that tenascin‐X interacts with types I, III and V fibrillar collagen molecules when they are in native conformation. The use of tenascin‐X variants with large regions deleted indicated that both epidermal growth factor repeats and the fibrinogen‐like domain are involved in this interaction. Moreover, we demonstrate that tenascin‐X binds to the fibril‐associated types XII and XIV collagens. We thus suggest that tenascin‐X, via trimerization and multiple interactions with components of collagenous fibrils, plays a crucial role in the organisation of extracellular matrices.
The signature of the planet Mercury in plants
Authors: Fyfe Agnes
Published: October 2006

1 Particular form-types may be distinguished in the sap pictures whatever thedegree of general configuration.

2 The cup form is described fully.

3 Methods used until now to evaluate the pictures have disregarded individualforms.

4 A method of producing the cup form artificially was found by adding amercury salt solution to the gold reagent.

5 The relation between the seven major metals and the planets led us toconsider whether the appearance of the cup form in pictures developed with the gold reagent only is connected with the position of the planet Mercury at the time when the plants are gathered.
Mediating Judaism: Mind, Body, Spirit, and Contemporary North American Jewish Fiction
Authors: Horowitz Sara R.
Published: October 2006

That Jewish literature in North America is an altogether secular venue has long been regarded as a truism among many influential literary scholars. Indeed, for much of the twentieth century, the fiction of Jewish immigrants and their progeny wrote its way into American and Canadian culture through narratives that captured the process of acculturation by distancing itself from Jewish traditional practices, construed mockingly or nostalgically as relics of a European life left behind, a wellspring of historical or textual memories that oppress or elevate. The few departures from this trend—fiction that represents Judaic ritual and experience sympathetically, with complexity and depth—are exceptions that prove the rule: Chaim Potok’s novels, for example, beginning in the late 1960s and continuing through the close of the twentieth century, and a handful of women novelists negotiating Jewish feminism in stories and novels of the 1980s and 1990s.
Beyond the Verse: Midrash Aggadah as Interpretation of Biblical Narrative
Authors: Steinmetz Devora
Published: October 2006

The 1980s saw the introduction of postmodern literary theory into the field of rabbinic literature, in particular into the study of midrash, which began to be explored as anticipating or aligning with many of the claims of modern literary theorists. This new interest intersected oddly at times with the prevailing historicist mode of inquiry. For many scholars, the notion of textual indeterminacy supported the idea of the interpreter of the text as essentially an “eisegete,” who reads the text from his or her own historically embedded perspective, rather than as an exegete, who at least attempts to find out what the text “really means.” Thus, scholars who embraced this new perspective often rejected an inquiry into midrash as biblical interpretation in the classic sense of the word. “No one believes anymore,” someone pointed out to me after a session on midrash in a conference during the mid-1980’s, “that texts have meaning.”
Diffusion of [3H]Dexamethasone in Rat Subcutaneous Slices after Injection Measured by Digital Autoradiography
Authors: Moussy Yvonne , Dungel Paul , Hersh Lawrence
Published: October 2006

A relatively simple method for the determination of the diffusion coefficient of a substance that has been injected into tissue is described. We illustrate this method using [3H]dexamethasone injected into the subcutaneous tissue of rats. Digital autoradiography was used to measure the distribution of the [3H]dexamethasone within the subcutaneous tissue at 2.5 and 20 min after injection. Measured concentration profiles of the injection were compared to a mathematical model of drug diffusion from an injection. There was good agreement between the experimental data and the mathematical model. The diffusion coefficient found using this simple injection method was (4.01 ± 2.01) × 10−10 m2/s. This D value was very close to the value of D = (4.11 ± 1.77) × 10−10 m2/s found previously using different mathematical and experimental techniques with osmotic pumps implanted for 6, 24, and 60 h in rats (1). The simple method given here for the determination of the diffusion coefficient is general enough to be applied to other substances and tissues as well.
Interaction of human GTP cyclohydrolase I with its splice variants
Authors: Pandya Maya J. , Golderer Georg , Werner Ernst R. , Werner-Felmayer Gabriele
Published: October 2006

Tetrahydrobiopterin is an essential cofactor for aromatic amino acid hydroxylases, ether lipid oxidase and nitric oxide synthases. Its biosynthesis in mammals is regulated by the activity of the homodecameric enzyme GCH (GTP cyclohydrolase I; EC 3.5.4.16). In previous work, catalytically inactive human GCH splice variants differing from the wild-type enzyme within the last 20 C-terminal amino acids were identified. In the present study, we searched for a possible role of these splice variants. Gel filtration profiles of purified recombinant proteins showed that variant GCHs form high-molecular-mass oligomers similar to the wild-type enzyme. Co-expression of splice variants together with wild-type GCH in mammalian cells revealed that GCH levels were reduced in the presence of splice variants. Commensurate with these findings, the GCH activity obtained for wild-type enzyme was reduced 2.5-fold through co-expression with GCH splice variants. Western blots of native gels suggest that splice variants form decamers despite C-terminal truncation. Therefore one possible explanation for the effect of GCH splice variants could be that inactive variants are incorporated into GCH heterodecamers, decreasing the enzyme stability and activity.
Rapid stimulation of tyrosine phosphorylation signals downstream of G-protein-coupled receptors for thromboxane A2 in human platelets
Authors: Minuz Pietro , Fumagalli Laura , Gaino Stefania , Tommasoli Rosa M. , Degan Maurizio , Cavallini Chiara , Lecchi Anna , Cattaneo Marco , Lechi Santonastaso Clara , Berton Giorgio
Published: October 2006

Signals ensuing from trimeric G-protein-coupled receptors synergize to induce platelet activation. At low doses, the thromboxane A2 analogue U46619 does not activate integrin αIIbβ3 or trigger platelet aggregation, but it induces shape changes. In the present study, we addressed whether low doses of U46619 trigger tyrosine phosphorylation independently of integrin αIIbβ3 activation and ADP secretion, and synergize with adrenaline (epinephrine) to induce aggregation in acetylsalicylic acid (aspirin)-treated platelets. Low doses of U46619 triggered tyrosine phosphorylation of different proteins, including FAK (focal adhesion kinase), Src and Syk, independently of signals ensuing from integrin αIIbβ3 or ADP receptors engaged by secreted ADP. The G12/13-mediated Rho/Rho-kinase pathway was also increased by low doses of U46619; however, this pathway was not upstream of tyrosine phosphorylation, because this occurred in the presence of the Rho-kinase inhibitor Y-27632. Although low doses of U46619 or adrenaline alone were unable to trigger platelet aggregation and integrin αIIbβ3 activation, the combination of the two stimuli effectively induced these responses. PP2, a tyrosine kinase inhibitor, and Y-27632 inhibited platelet activation induced by low doses of U46619 plus adrenaline and, when used in combination, totally suppressed this platelet response. In addition, the two inhibitors selectively blocked tyrosine kinases and the Rho/Rho-kinase pathway respectively. These findings suggest that both tyrosine phosphorylation and the Rho/Rho-kinase pathway are required to activate platelet aggregation via G12/13 plus Gz signalling.
Influence of the direct response on the heterodyne sensitivity of hot electron bolometer mixers
Authors: Baselmans J. J. A. , Baryshev A. , Reker S. F. , Hajenius M. , Gao J. R. , Klapwijk T. M. , Voronov B. , Gol’tsman G.
Published: October 2006

We present a detailed experimental study of the direct detection effect in a small volume (0.15μm×1μm×3.5nm) quasioptical NbN phonon cooled hot electron bolometer mixer at 673GHz. We find that the small signal noise temperature, relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 and 77K calibration loads. In a separate set of experiments we show that the direct detection effect is caused by a combination of bias current reduction when switching from the 77 to the 300K load in combination with the bias current dependence of the receiver gain. The bias current dependence of the receiver gain is shown to be mainly caused by the current dependence of the mixer gain.
Experimental and theoretical investigation of rate coefficients of the reaction S(P3)+OCS in the temperature range of 298–985K
Authors: Lu Chih-Wei , Wu Yu-Jong , Lee Yuan-Pern , Zhu R. S. , Lin M. C.
Published: October 2006

The reaction S(P3)+OCS in Ar was investigated over the pressure range of 50–710Torr and the temperature range of 298–985K with the laser photolysis technique. S atoms were generated by photolysis of OCS with light at 248nm from a KrF excimer laser; their concentration was monitored via resonance fluorescence excited by atomic emission of S produced from microwave-discharged SO2. At pressures less than 250Torr, our measurements give k(298K)=(2.7±0.5)×10−15cm3molecule−1s−1, in satisfactory agreement with a previous report by Klemm and Davis [J. Phys. Chem. 78, 1137 (1974)]. New data determined for 407–985K connect rate coefficients reported previously for T⩾860 and T⩽478K and show a non-Arrhenius behavior. Combining our results with data reported at high temperatures, we derived an expression k(T)=(6.1±0.3)×10−18T1.97±0.24exp[−(1560±170)∕T]cm3molecule−1s−1 for 298⩽T∕K⩽1680. At 298K and P⩾500Torr, the reaction rate was enhanced. Theoretical calculations at the G2M(CC2) level, using geometries optimized with the B3LYP∕6-311+G(3df) method, yield energies of transition states and products relative to those of the reactants. Rate coefficients predicted with multichannel Rice–Ramsperger–Kassel–Marcus (RRKM) calculations agree satisfactorily with experimental observations. According to our calculations, the singlet channel involving formation of SSCO followed by direct dissociation into S2(aΔg1)+CO dominates below 2000K; SSCO is formed via intersystem crossing from the triplet surface. At low temperature and under high pressure the stabilization of OCS2, formed via isomerization of SSCO, becomes important; its formation and further reaction with S atoms partially account for the observed increase in the rate coefficient under such conditions.
Low frequency dielectric response of mechanosynthesized (Pb0.9Ba0.1)(Fe0.50Nb0.50)O3 nanoceramics
Authors: Varshney Deepak , Choudhary R. N. P. , Katiyar R. S.
Published: October 2006

The nanocrystalline (40nm) samples of Pb(Fe0.50Nb0.50)O3 (PFN) and Pb0.90Ba0.1(Fe0.5Nb0.5)O3 (PBFN) were synthesized by mechanosynthesis and mixed oxide methods. Preliminary structural analysis of these samples showed that tetragonal PFN can be distorted to orthorhombic structure on 10% Ba substitution in it. One of the relaxor characteristics (i.e., diffuse phase transition with low frequency dielectric dispersion) was observed in PBFN with a decrease in the transition temperature from 380K (PFN) to 170K. The suggested relaxor behavior in a new PFN composition is possibly due to compositional fluctuations at the nanolevel.
Thermally activated charge reversibility of gallium vacancies in GaAs
Authors: El-Mellouhi Fedwa , Mousseau Normand
Published: October 2006

The dominant charge state for the Ga vacancy in GaAs has been the subject of a long debate, with experiments suggesting −1, −2, or −3 as the best answer. We revisit this problem using ab initio calculations to compute the effects of temperature on the Gibbs free energy of formation, and we find that the thermal dependence of the Fermi level and of the ionization levels lead to a reversal of the preferred charge state as the temperature increases. Calculating the concentrations of gallium vacancies based on these results, we reproduce two conflicting experimental measurements, showing that these can be understood from a single set of coherent local density approximation results when thermal effects are included.
Role of elastic scattering mechanisms in GaInAs∕AlInAs quantum cascade lasers
Authors: Vasanelli A. , Leuliet A. , Sirtori C. , Wade A. , Fedorov G. , Smirnov D. , Bastard G. , Vinter B. , Giovannini M. , Faist J.
Published: October 2006

Electron scattering spectroscopy has been performed on a GaInAs∕AlInAs midinfrared quantum cascade laser by applying a strong magnetic field along its growth axis. The interpretation of the experimental data, supported by our model of the electron lifetime in the presence of a strong magnetic field, very clearly demonstrates that the elastic contribution to the total scattering rate has a weight comparable to that of the optical phonons. The authors believe that this contribution has its origin in the alloy disorder, an efficient mechanism in this material system, which limits the lifetime of the excited subband of the laser transition.
Relativistic calculation of nuclear magnetic shielding tensor including two-electron spin-orbit interactions
Authors: Ootani Y. , Yamaguti H. , Maeda H. , Fukui H.
Published: October 2006

A relativistic calculation of nuclear magnetic shielding tensor including two-electron spin-orbit interactions is performed. In order to reduce the computational load in evaluating the two-electron relativistic integrals, the charge density is approximated by a linear combination of the squares of s-type spatial basis functions. Including the two-electron spin-orbit interaction effect is found to improve the calculation results.
Integrated tunneling sensor for nanoelectromechanical systems
Authors: Sadewasser S. , Abadal G. , Barniol N. , Dohn S. , Boisen A. , Fonseca L. , Estéve J.
Published: October 2006

Transducers based on quantum mechanical tunneling provide an extremely sensitive sensor principle, especially for nanoelectromechanical systems. For proper operation a gap between the electrodes of below 1nm is essential, requiring the use of structures with a mobile electrode. At such small distances, attractive van der Waals and capillary forces become sizable, possibly resulting in snap-in of the electrodes. The authors present a comprehensive analysis and evaluation of the interplay between the involved forces and identify requirements for the design of tunneling sensors. Based on this analysis, a tunneling sensor is fabricated by Si micromachining technology and its proper operation is demonstrated.
Modeling multiple quantum barrier effects and reduced electron leakage in red-emitting laser diodes
Authors: Brown M. R. , Cobley R. J. , Teng K. S. , Rees P. , Wilks S. P. , Sobiesierski A. , Smowton P. M. , Blood P.
Published: October 2006

Severe electron leakage impedes the full exploitation of AlGaInP laser diodes in the 630nm regime. Such thermally activated currents are attributed to inherently small conduction band offsets and intervalley transfer between the Γ and X conduction band minima. To negate the detrimental effect of these two intrinsic material issues a theoretical model is proposed. A multi-quantum-barrier (MQB) structure able to inhibit both Γ- and X-band transmissions is inserted in the p-doped region adjacent to the active region of the device, allowing a greater percentage of injected electrons to be reflected back within the active region. The design of the MQB follows a strict optimization procedure that takes into account fluctuations of superlattice layer width and composition. This model is used in conjunction with a dual conduction band drift-diffusion simulator to enable the design of the MQB at an operating voltage and hence account for nonlinear charge distribution across it. Initial results indicate strong agreement between experimentally determined effective enhancements and those predicted theoretically.
Spatially confined alloy single crystals for model studies of volumetrically constrained phase transformations
Authors: Sugar Joshua D. , McKeown Joseph T. , Glaeser Andreas M. , Gronsky Ronald , Radmilovic Velimir
Published: October 2006

The authors present a method to fabricate confined, oriented, single crystals of ternary alloys within an inert ceramic matrix. Pulsed-laser deposition of a polycrystalline CuNiFe film fills lithographically defined surface cavities in a sapphire single crystal. Solid-state diffusion bonding to a second sapphire crystal internalizes the metal-filled cavities. Electron microscopy verifies that subsequent heat treatment converts the thin, fully constrained films into single crystals of specific orientation by nucleation-controlled liquid-phase epitaxy during cooling from above the alloy melting temperature. The resulting films provide an ideal medium for fundamental studies of a wide range of volumetrically constrained phase transformations.
Mechanism of improved channel carrier mobility for stacked Y2O3∕HfO2 gate dielectric
Authors: Zhu Feng , Kang Chang Yong , Rhee Se Jong , Choi Chang Hwan , Krishnan Siddarth A. , Zhang Manhong , Kim Hyoung-Sub , Lee Taekhwi , Ok Injo , Thareja Gaurav , Lee Jack C.
Published: October 2006

Stacked Y2O3∕HfO2 gate dielectric, compared to HfO2, shows significantly enhanced electron channel mobility at different temperatures. This mobility improvement can be attributed to reduced remote phonon scattering, which is associated with the smaller ionic polarization of Y2O3, and the suppressed Coulomb scattering due to less electron trapping in the bulk of high-κ layer and reduced metal impurities in the substrate.
Anisotropic field-effect mobility of pentacene thin-film transistor: Effect of rubbed self-assembled monolayer
Authors: Weng Shou-Zheng , Hu Wei-Shan , Kuo Chi-Hsien , Tao Yu-Tai , Fan Liang-Jen , Yang Yaw-Wen
Published: October 2006

Enhanced and anisotropic field-effect mobility of thin-film transistors based on pentacene was obtained on a substrate covered with a prerubbed, self-assembled monolayer (SAM) of n-alkyltrichlorosilane. The field-effect mobility along the rubbing direction increased by a factor of ∼15 on rubbed n-nonyltrichlorosilane-modified surface, whereas on n-octadecyltrichlorosilane-modified surface, an increase by a factor of 2–4 was observed. The structures of pentacene films deposited on the SAM/rubbed SAM were characterized by powder x-ray diffraction, atomic force microscopy, and carbon K-edge near edge x-ray fine structure spectroscopy. An in-plane alignment effect on the pentacene packing and film morphology is proposed.
Magnetoresistivity of cobalt-polytetrafluoroethylene granular composites
Authors: Kwong H. Y. , Wong M. H. , Wong Y. W. , Wong K. H.
Published: October 2006

Giant magnetoresistance (GMR) was observed in a heterogeneous granular film with polymer matrix. Cobalt and polytetrafluoroethylene (PTFE) were deposited on glass substrates by using the pulsed laser deposition technique. IR absorption spectra of the deposited PTFE showed similar characteristics with the bulk PTFE. The granular samples exhibit a resistance change of about 5% (at 10kOe) at room temperature. The temperature dependence of resistance of the samples shows that charge transportation is mainly due to tunneling between the metal particles. The GMR can thus be interpreted by the spin-dependent electrons tunneling through the ferromagnetic metal granules (cobalt) in the insulating matrix (PTFE).
Tip traveling and grain boundary effects in domain formation using piezoelectric force microscopy for probe storage applications
Authors: Kim Yunseok , Cho Youngsang , Hong Seungbum , Bühlmann Simon , Park Hongsik , Min Dong-Ki , Kim Seung-Hyun , No Kwangsoo
Published: October 2006

Tip traveling and grain boundary effects have been investigated by varying the voltage pulse width on Pb(Zr0.25Ti0.75)O3 films using piezoelectric force microscopy. Depending on pulse width, the authors distinguish three regions of domain formation. It was found that grain boundaries act as electric shield, which prevents domain growth across grains. Domain growth across grains was mainly due to the tip traveling effect. Calculations based on the authors’ model matched well with experimental data.
High-mobility AlAs quantum wells with out-of-plane valley occupation
Authors: Vakili K. , Shkolnikov Y. P. , Tutuc E. , De Poortere E. P. , Padmanabhan M. , Shayegan M.
Published: October 2006

Employing state-of-the-art molecular beam epitaxy techniques to grow thin, modulation-doped AlAs quantum wells, we have achieved a low temperature mobility of 5.5m2∕Vs with out-of-plane occupation, an order of magnitude improvement over previous studies. However, from the narrow well width, mobilities are still limited by scattering due to interface roughness disorder. We demonstrate the implementation of a technique utilizing thermally induced, biaxial, tensile strain that forces electrons to occupy the out-of-plane valley in thicker quantum wells, reducing interface roughness scattering and allowing us to achieve mobilities as high as 8.8m2∕Vs.
Silicon single electron transistors aiming at a high gate modulation factor
Authors: Chen Jiezhi , Shi Yi , Pu Lin , Zheng Youdou , Long Shibing , Liu Ming
Published: October 2006

The authors report on the fabrication of a Si-based single electron transistor (SET), in which the gate is formed just on the top of quantum dots (QDs). By this kind of structure, the gate modulation factor can be modulated to be high, which provides a promising approach to improve the voltage gain. It is demonstrated that the gate modulation factor achieves 0.84 in the fabricated SET device with sub-10-nm QD at room temperature. The transport characteristics with Coulomb blockade oscillations and negative differential conductance are discussed.