bluuebunny/crossref_metadata_2025 huggingface dataset:
LIMIT AND SHAKEDOWN ANALYSIS OF RC ROD CROSS-SECTIONS
Authors: Aliawdin Piotr , Kasabutski Sergei
Published: March 2009

This paper presents the calculation of the cross‐section of an RC rod element strength under the quasistatic low‐cyclic loadings, considering the non‐linear stress‐strain relations of materials without cracks. Some mathematical models of the limit and shakedown analysis proposed by the authors involve the technique of calculating the cross‐section under one‐path loadings, considering the non‐uniqueness of problem solutions. The plasticity conditions for the materials of the cross‐section are formulated either in stress or in strain space. Simple solutions of two types, direct and inverse, corresponding to the limit states for alternating plasticity or progressive failure, are considered for the non‐linear optimization problems obtained.

Santrauka

Nagrinėjamas nepleišėjančio gelžbetoninio elemento skerspjūvio stiprio skaičiavimas veikiant mažaciklei apkrovai. Naudojama netiesinė medžiagos įtempių-deformacijų priklausomybė. Pateikiami ribinės pusiausvyros ir prisitaikomumo analizavimo uždavinių matematiniai modeliai. Naudojama metodika skerspjūvio parinkimui vienos trajektorijos apkrovimo atvejais, nagrinėjamas uždavinio sprendinių nevieninteliškumas. Medžiagos plastiškumo sąlygos formuluojamos įtempiais arba deformacijomis. Sprendžiant netiesinio optimizavimo uždavinius gaunami paprasti dviejų tipų sprendiniai: tiesioginis ir atvirkštinis, atitinkantys progresuojančio arba kintamo plastiškumo ribinius plastinio suirimo atvejus.
ASSESSMENT OF STRUCTURES SUBJECTED TO ACCIDENTAL ACTIONS USING CRISP AND UNCERTAIN FRAGILITY FUNCTIONS
Authors: Vaidogas Egidijus R. , Juocevičius Virmantas
Published: March 2009

An application of fragility functions to the assessment of potential damage due to an accidental action is analysed. The assessment is carried out as an estimation of the probability of a foreseeable damage event (damage probability). This probability is expressed as a mean value of a fragility function developed for the damage event under study. A Bayesian prior (posterior) distribution specified for this mean value is used as an estimate of the damage probability. The prior distribution is derived by transforming prior knowledge through the fragility function and “mapping” this knowledge on the scale of probability values. The technique of Bayesian bootstrap resampling is applied to update the prior distribution. The new information used for the updating consists of a relatively small number of experimental observations of the accidental action. To facilitate the updating, these observations are transformed into a fictitious statistical sample of fragility function values. The updating is first carried out with a fragility function which expresses aleatory uncertainty only. Then it is proposed how to perform the updating with the fragility function which quantifies both aleatory and epistemic uncertainty. This is done by discretising continuous distributions of the epistemic uncertainty related to values (parameters) of the fragility function. The proposed approach allows to utilise different sources of information for the damage assessment. A potential field of application of this approach is risk studies of hazardous industrial facilities. Santrauka Analizuojamas pažeidžiamumo funkcijų taikymas vertinant potencialius statybinių konstrukcijų pažeidimus avariniais poveikiais. Vertinimas atliekamas skaičiuojant galimos konstrukcijos pažaidos tikimybę. Ši tikimybė yra išreiškiama vidutine pažeidžiamumo funkcijos reikšme. Ta funkcija yra formuojama analizuojamam pažaidos įvykiui. Apriorinis ir aposteriorinis Bajeso skirstiniai yra taikomi pažaidos tikimybės reikšmei vertinti. Apriorinis skirstinys yra gaunamas pasinaudojant turima informacija apie avarinį poveikį ir transformuojant šią informaciją per pažeidžiamumo funkciją. Aposteriorinis skirstinys yra gaunamas pasitelkiant naują, eksperimentinę informaciją apie avarinį poveikį. Aposterioriniam skirstiniui gauti taikomas kartotinio statistinio ėmimo (būtstrapo) metodas. Naują informaciją sudaro eksperimentiniai avarinio poveikio charakteristikų matavimai, kurie tiksliai atitinka konstrukcijos ekspozicijos tiriamo poveikio situaciją. Apriorinis ir aposteriorinis skirstiniai išreiškia episteminį neapibrėžtumą vertinamos pažaidos tikimybės reikšmės atžvilgiu. Šie skirstiniai yra gaunami taikant tiek pažeidžiamumo funkciją, kuri išreiškia tik stochastinį neapibrėžtumą, tiek funkciją, kurios reikšmės yra neapibrėžtos epistemine prasme. Potenciali siūlomo metodo taikymo sritis yra pavojingų pramoninių objektų rizikos vertinimas.
Incorporation of medium chain fatty acids into fish oil triglycerides by chemical and enzymatic interesterification
Authors: Feltes Maria M. C. , De Oliveira Pitol L. , Gomes Correia J. F. , Grimaldi R. , Block J. Mara , Ninow Jorge L.
Published: March 2009

Structured triglycerides (STs) containing both medium-chain fatty acids (MCFA) and polyunsaturated fatty acids (PUFA) in the same molecule offer nutritional and therapeutic benefits. The aim of this work was to establish the incorporation of MCFA into fish oil triglycerides (TAGs), while maintaining substantial levels of docosahexaenoic and eicosapentaenoic acids. The effects of different acyl donors (capric acid methyl ester/MeC10 or medium chain triglyceride/TCM) and of the catalyst (chemical or enzymatic) on the fatty acid composition of the reaction product were studied. The fatty acid composition of the fish oil TAG was modified after interesterification to contain MCFA, and it depended on the catalyst and on the substrates. Thermograms obtained by Differential Scanning Calorimetry (DSC) showed that interesterification promoted noteworthy changes in the melting profile of the samples. STs of clinical nutrition interest containing both EPA and DHA obtained from fish oil along with MCFA were successfully produced.
Antimicrobial activity of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria
Authors: Kacem Mourad , Kazouz Fadhila , Merabet Chahinez , Rezki Meriem , De Lajudie Philippe , Bekki Abdelkader
Published: March 2009

In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the “small” bacteriocins described in other rhizobia.
Nutritional composition of new Peanut (Arachis hypogaea L.) cultivars
Authors: Campos-Mondragón M. G. , Calderón De La Barca A. M. , Durán-Prado A. , Campos-Reyes L. C. , Oliart-Ros R. M. , Ortega-García J. , Medina-Juárez L. A. , Angulo O.
Published: March 2009

Six peanut (Arachis hypogaea L.) cultivars (Col-24-Gro, Col-61-Gto, VA-81-B, Ranferi Díaz, NC-2 and Florunner) were studied for agricultural yield, chemical composition (protein, fat, carbohydrates, fiber and ash), amino acid profile, digestibility, fatty acid profile, tocopherol and sterol contents. Results indicated that Ranferi Díaz and Col-61-Gto presented the highest yield (6.3 Ton/ha). Protein content was from 23.5 to 26.6% and fat content ranged from 49.8-53.4%. Mean digestibility was 86%. Lysine and threonine levels in all cultivars were sufficient to meet human requirements. Total saturated fatty acids ranged from 15-18%. The oleic/linoleic ratio was estimated 1.3-1.4. Tocopherol levels varied from 390 to 706 ppm. The highest tocopherol levels corresponded to the cultivars with the lowest yield. The alpha tocopherol content was estimated at 90-150 ppm, while gamma tocopherol was 270-570 ppm.The main sterol present was βsitosterol (approx. 65%). Ranferi Diaz variety presented the highest agronomic yield and the highest protein content but low oleic acid, low sterols and low total tocopherols. The differences among cultivars suggest differences in their applications.
Docosahexaenoic acid (DHA), an essential fatty acid for the proper functioning of neuronal cells: their role in mood disorders
Authors: Valenzuela B Alfonso
Published: March 2009

The brain and the nervous system are tissues with high contents of two polyunsaturated fatty acids: arachidonic acid (20:4, omega-6, AA) and docosahexaenoic acid (22:6, omega-3, DHA). Despite their abundance in these tissues, AA and DHA cannot be re-synthesized in mammals. However, the concentration of these fatty acids can be modulated by dietary intake. AA and DHA must be provided by the diet as such (preformed) or through the respective omega-6 and omega-3 precursors from vegetable origin. Linoleic acid, the precursor of AA is very abundant in the western diet and therefore the formation of AA from linoleic acid is not restrictive. On the other hand, alpha linolenic acid, the precursor of DHA is less available in our diet and preformed DHA is highly restrictive in some populations. During the last period of gestation and during the early post natal period, neurodevelopment occurs exceptionally quickly, and significant amounts of omega-6 and omega-3 polyunsaturated fatty acids, especially DHA, are critical to allow neurite outgrowth and the proper brain and retina development and function. In this review various functions of DHA in the nervous system, its metabolism into phospholipids, and its involvement in different neurological and mood disorders, such as Alzheimer’s disease, depression, and others are revised.
Lactic acid bacteria from "Sheep's Dhan", a traditional butter: Isolation, identification and major technological traits
Authors: Idoui Tayeb , Boudjerda Jamel , Leghouchi Essaid , Karam Nour-Eddine
Published: March 2009

Twenty six lactic acid bacteria were isolated from sheep’s Dhan, a traditional butter made from sheep’s milk in Jijel (East of Algeria). These strains belong to three genera: Lactococcus, Leuconostoc and Lactobacillus. The results showed that Lactococcus lactis ssp diacetylactis was the predominant species in this traditional butter. The results of the assessment of the technological aptitude indicate that a major strain has a good acidification aptitude, some of them show good proteolytic activity and only Leuconostoc mesenteroides ssp. dextranicum isolates were able to produce exopolysaccharide.
Antioxidant properties of some plants growing wild in Turkey
Authors: Serteser A. , Kargıoğlu M. , Gök V. , Bağci Y. , Özcan M. Musa , Arslan D.
Published: March 2009

In this study, the antioxidant activity of 50% aqueous methanol extracts of 38 plants growing in the Afyonkarahisar province of Turkey were evaluated by various antioxidant assay, including free radical scavenging, hydrogen peroxide (H2O2) scavenging and metal (Fe2+) chelating activities. The methanolic fruit extracts of the Cornus and Morus species (H2O2 and DPPH scavenging activities, Fe2+ chelating activity) and the methanolic leaf extracts of the Mentha species (DPPH scavenging activities) examined in the assay showed the strongest activities. These antioxidant properties depended on the concentration of samples.
Relationship between changes in peroxide value and conjugated dienes during oxidation of sunflower oils with different degree of unsaturation
Authors: Marmesat S. , Morales A. , Velasco J. , Ruiz-Méndez M. V. , Dobarganes M. C.
Published: March 2009

Peroxide value and the determination of conjugated dienes by UV absorption at 232 nm are normally applied alternatively for the evaluation of primary oxidation compounds. The objective of this study was to define the relationship between both indexes during oil oxidation in sunflower oils with different degree of unsaturation. The oils studied were conventional sunflower oil (SO) and high oleic sunflower oil (HOSO). For comparative purposes, methyl linoleate, whose hydroperoxides are conjugated diene hydroperoxides, was also studied. Samples were oxidized at 40 °C in the dark. In order to accelerate oxidation at 40 °C, the natural antioxidants present in the oils were removed, and a high surface to oil volume ratio (0.8 cm-1) was applied to guarantee total air availability. Linear regressions with high correlation coefficients between peroxide values and conjugated dienes were found for the three lipid systems studied (0.9988, 0.9991 and 0.9977 for methyl linoleate, SO and HOSO, respectively). Significant differences in the slopes of the lines were found (0.0974, 0.0854 and 0.0503 for methyl linoleate, SO and HOSO, respectively), indicating the formation of non-conjugated hydroperoxides from oleic acid in the oils, even in the oxidation of SO with a high degree of unsaturation. Consequently, only peroxide value would be reliable for the evaluation of primary oxidation compounds in oils of different degree of unsaturation, unless adequate calibration lines (peroxide value versus conjugated dienes) are applied.
FUZZY C-MEANS CLUSTERING FOR MYOCARDIAL ISCHEMIA ESTIMATION WITH PULSE WAVEFORM ANALYSIS
Authors: Liu Shing-Hong , Chang Kang-Ming , Tyan Chu-Chang
Published: March 2009

The purpose of this study is to build an automatic disease classification algorithm by pulse waveform analysis, based on a Fuzzy C-means clustering algorithm. A self designed three-axis mechanism was used to detect the optimal position to accurately measure the pressure pulse waveform (PPW). Considering the artery as a cylinder, the sensor should detect the PPW with the lowest possible distortion, and hence an analysis of the vascular geometry and an arterial model were used to design a standard positioning procedure based on the arterial diameter changed waveform for the X-axes (perpendicular to the forearm) and Z-axes (perpendicular to the radial artery). A fuzzy C-means algorithm was used to estimate the myocardial ischemia symptoms in 35 elderly subjects with the PPW of the radial artery. Two type parameters were used to make the features, one was a harmonic value of Fourier transfer, and the other was a form factor value. A receiver operating characteristics curve was used to determine the optimal decision function. The harmonic feature vector contain second, third and fourth harmonics ( H 2, H 3, H 4) performed at the level of 69% for sensitivity and 100% for specificity while the form factor feature vector derived from left hand (LFF) and right hand (RFF) performed at the level of 100% for sensitivity and 53% for specificity. The FCM- and ROC-based clustering approach may become an efficient alternative for distinguishing patients in the risk of myocardial ischemia, besides the traditional exercise ECG examination.
AUDITORY DISPLAY WITH SENSORY SUBSTITUTION FOR INTERNET-BASED TELEOPERATION: A FEASIBILITY STUDY
Authors: Liu Rong
Published: March 2009

A critical challenge in telerobotic system is data communication over networks without performance guarantee. This paper proposes a novel way of using auditory feedback as the sensory feedback to ensure that the teleoperated robotic system still functions in a real-time fashion under the unfavorable communication conditions, such as image losses, visual failures, and low-bandwidth communication links. The newly proposed method is tested through psychoacoustic experiments with 10 subjects conducting real-time robotic navigation tasks. The performance is analyzed according to an objective point of view (time to finish task, distance away to the target measurements), as well as subjective workload assessments for different sensory feedbacks. Moreover, the bandwidth consumed when auditory information is applied is considerably lower, compared with the visual information. Preliminary results demonstrate the feasibility of auditory display as a complement or substitute to visual display for remote robotic navigation.
THE DRUG RELEASE FROM LIPOSOMAL CARRIER WITHIN THE CHITOSAN MATRIX
Authors: Chiang Hongsen , Huang Yi-Cheng , Yeh Huei-Yu , Yeh Szu-Yi , Huang Yi-You
Published: March 2009

The release and regulation of growth factors are very important in the tissue regeneration. Optimal and suitable drug carrier systems combined with scaffold are needed to be exploited. In this study, we developed an injectable scaffold incorporated with drug release system for tissue regeneration. Hydrophilic or hydrophobic drugs can be encapsulated into liposomes and then dispersed in the temperature-reversible chitosan-glycerophosphate (GP) hydrogel. Experimental results show that liposomes provide excellent sustained drug release from chitosan matrix when compared with that of free drugs, especially for hydrophilic drugs. The negative charge of the liposome will complex with the positive charge of the chitosan's protonized amine group that results in controlling the drugs release.
THE BIOMECHANICAL ANALYSIS OF MYOSIN V IN MULTIPLE-PATHS MODEL
Authors: Hsu Hsiu-Hao , Huang Ming-Jer , Chou Pei-Hsi , Huang Yen-Po , Chen Hsin-Chieh , Chou You-Li
Published: March 2009

Myosin V, a two-headed motor protein, moves along actin filaments toward the positive end. Similar to other molecular motors, myosin V hydrolyzes Adenosine tri-phosphate (ATP) and releases its product to produce movement. This study proposes a multiple-paths model that considers the hydrolysis processes of catalytic sites at the two heads of myosin V as independent. The proposed model describes the myosin V transition process by seven states, with one load-dependent transition rate among these states. This model demonstrates how myosin V steps forward at different chemical reaction paths. This study also uses the enzyme kinetics to calculate the mean velocity. Stochastic processes are used to analyze the randomness as well. Analytical results reveal that the theoretical mean velocities, mean movement lengths, and randomness with various ATP concentrations under external load agree with the experimental data.
APPLICATIONS OF CHAMBER DEVICES WITH NONLINEAR OPTICAL IMAGE SYSTEM
Authors: Chen Te-Hsuen , Huang Yi-You
Published: March 2009

In this study, we use laser to fabricate the plastic chamber for animal experiments in vivo. Laser cutting plastics process offers to cut a complex shape at high speed with the absence of hot stress and deformation. We combine this novel method to fabricate the dorsal skinfold plastic chamber and the ear plastic chamber. The chamber was applied on the nude mice and combined with optical system to improve the time of observation and the position of accuracy. The plastic dorsal skinfold chamber (DSC) exhibited good properties than the metallic DSC. The metallic DSC only offered monitoring for more than seven days after implantation. In contrast with the metallic DSC, the plastic DSC enabled monitoring to be observed for more than 12 days after implantation. This plastic DSC and ear chamber are more applications on short-term and long-term mode of disease. These chamber techniques combined with nonlinear microscopy will have many applications in clinic. The nonlinear optical effects have advantages for monitoring the biological processes, such as cellular autofluorescences were excited by two photons excitation and collagen structures were observed by second harmonic generation. The chamber model combines with nonlinear optical microscopy to visualizing cells and tissue structures in vivo. This chamber model allows repeat observation of the same sites for long periods of time and investigation of cells and collagen structures interaction without histological staining and sacrificed animals.
Nutritional, developmental, and genetic influences on relative sitting height at high altitude
Authors: Stinson Sara
Published: March 2009

The study explores how nutritional status, developmental exposure to high‐altitude hypoxia, and genetic ancestry influence relative sitting height in two groups of high‐altitude Bolivian children aged 8 through 13 years of age: 253 rural Aymara children of very low socioeconomic status and 273 children of upper socioeconomic status from the capital city of La Paz. The rural Aymara children on average have longer trunks relative to stature, but there is also overlap in body proportions between the two groups of children. The 20% of each sample in the region of overlap was examined to investigate influences on relative sitting height. Nutritional effects on relative sitting height are suggested by the finding that Aymara children with relatively long legs are taller, heavier, and fatter than other Aymara children. Developmental and genetic influences on relative sitting height are suggested by the finding that high relative sitting heights in elite urban children are associated with a greater percentage of time lived at high altitude and with parents born in Bolivia. Separating developmental and ancestry effects is difficult because the two are closely interconnected in the urban children. The results of this study suggest that influences on growth in relative trunk and leg length are similar to those that affect other aspects of growth in Andean populations. They also highlight the fact that because relative sitting height gradually decreases prior to adolescence and then increases, the interpretation of variation in body proportions in children is not always straightforward. Am. J. Hum. Biol. 2009. © 2009 Wiley‐Liss, Inc.
Malaria during pregnancy in endemic areas: A lens for examining maternal–fetal conflict
Authors: Abrams Elizabeth T. , Meshnick Steven R.
Published: March 2009

Most of our knowledge about maternal–fetal conflict derives from the battle over scarce nutritional resources. How do other stressors like infectious diseases alter the maternal–fetal relationship? In this article, we use the example of malaria infection during pregnancy to explore the altered maternal–fetal relationship in the presence of an infectious disease. While adults living in regions endemic to Plasmodium falciparum malaria are generally immune, pregnant women experience significantly more frequent and severe infections. These infections generally resolve within a few days of birth and rarely cross the placenta, but the infants often experience poor birth outcomes, particularly low birth weight. This article summarizes what is known about the proximate, or physiological, mechanisms by which malaria causes more severe or frequent infections for pregnant versus nonpregnant women in endemic regions and then utilizes an evolutionary approach to focus on the altered maternal–fetal relationship during malaria‐infected pregnancy. Am. J. Hum. Biol. 2009. © 2009 Wiley‐Liss, Inc.
Iron Polyoxometalate Single‐Molecule Magnets
Authors: Compain Jean‐Daniel , Mialane Pierre , Dolbecq Anne , Mbomekallé Israël Martyr , Marrot Jérôme , Sécheresse Francis , Rivière Eric , Rogez Guillaume , Wernsdorfer Wolfgang
Published: March 2009

Wolframate mit Eisenfüllung: Zwei neue Polyoxowolframate mit paramagnetischen Eisen(III)‐Ionen (siehe Struktur, W blau, Fe gelb, O rot) haben Grundzustände mit S=15/2 und S=5. Beide Verbindungen sind Einzelmolekülmagnete, und die Hexaeisen‐Spezies zeigt eine starke Hysterese (siehe Diagramm) sowie Quantentunneleffekte bei tiefen Temperaturen. Elektrochemischen Untersuchungen zufolge sollten die Spezies in Lösung über einen großen pH‐Bereich beständig sein.

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How Do Redox Groups Behave around a Rigid Molecular Platform? Hexa(ferrocenylethynyl)benzenes and Their “Electrostatic” Redox Chemistry
Authors: Diallo Abdou K. , Daran Jean‐Claude , Varret François , Ruiz Jaime , Astruc Didier
Published: March 2009

Durch die Negishi‐Kupplung von Ethinylferrocenen mit C6Br6 wurde eine neue Familie von Hexakis(ferrocenylethinyl)benzolen synthetisiert, die reversibel zu stabilen Hexaferrocenium‐Salzen oxidiert werden können (siehe Bild, ArF=[3,5‐C6H3(CF3)2]). Je nach Gegenion und Zahl der Methylsubstituenten an den Ferrocenylgruppen zeigen die Cyclovoltammogramme eine einzelne Sechselektronenwelle, drei Zweielektronenwellen oder eine Kaskade von sechs Einelektronenwellen.

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The Fluorine‐Iminium Ion Gauche Effect: Proof of Principle and Application to Asymmetric Organocatalysis
Authors: Sparr Christof , Schweizer W. Bernd , Senn Hans Martin , Gilmour Ryan
Published: March 2009

Der gauche‐Effekt, der bei der reversiblen Bildung eines Iminiumions (siehe Struktur: F grün, N blau) auftritt, bietet eine nützliche Möglichkeit, die räumliche Ausrichtung von Intermediaten in durch sekundäre Amine katalysierten Reaktionen zu steuern. Dieses Phänomen wurde beim Entwurf eines neuartigen Organokatalysators genutzt und bei der stereoselektiven Epoxidierung von α,β‐ungesättigten Aldehyden angewendet.

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Hohe elektrische Leitfähigkeit einzelner Moleküle – eine Herausforderung in der Reihe der konjugierten Oligomere
Authors: Meier Herbert
Published: March 2009

Auf dem Weg zu molekularer Elektronik: Ausgedehnte konjugierte Oligomere sind wünschenswert für die molekulare Elektronik, ihre elektrische Leitfähigkeit sollte hierfür jedoch einen niedrigen Abklingfaktor aufweisen. Nun wurden die abgebildeten Zink‐komplexierten Oligo(ethinylenporphyrindiylethinylene) entwickelt, die sich durch ultraniedrige Abklingfaktoren der Einzelmolekül‐Leitfähigkeit auszeichnen.

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Relative Orientation of Rigid Nitroxides by PELDOR: Beyond Distance Measurements in Nucleic Acids
Authors: Schiemann Olav , Cekan Pavol , Margraf Dominik , Prisner Thomas F. , Sigurdsson Snorri Th.
Published: March 2009

Show me your angle: Incorporation of the rigid spin labelÇallows determination of both distance and orientation of two nitroxide spin labels in DNA by PELDOR experiments at common X‐band frequencies. The orientational information is obtained by varying the position of the detection pulses over the nitroxide spectrum. Simulation of the set of time traces yields very precise distances and angles.

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A Dinuclear Nickel(I) Dinitrogen Complex and its Reduction in Single‐Electron Steps
Authors: Pfirrmann Stefan , Limberg Christian , Herwig Christian , Stößer Reinhard , Ziemer Burkhard
Published: March 2009

Electron by electron: β‐Diketiminato nickel(I) complex fragments are capable of activating N2 through coordination. The resulting complex can be reduced in two single‐electron steps, which further activates the NN bond. The picture shows the structure of the singly reduced complex with μ‐η1:η1‐bound N2.

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Complete Chiral Resolution Using Additive‐Induced Crystal Size Bifurcation During Grinding
Authors: Noorduin Wim L. , van der Asdonk Pim , Meekes Hugo , van Enckevort Willem J. P. , Kaptein Bernard , Leeman Michel , Kellogg Richard M. , Vlieg Elias
Published: March 2009

Grinding them down: By using a tailor‐made additive, even in the absence of racemization in solution, abrasive grinding can yield an enantiopure solid state. This novel chiral resolution technique is based on an asymmetric bifurcation in the crystal size distribution as a result of stereoselective hampered crystal growth. R=o‐tolyl.

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The Regio‐ and Stereoselective Synthesis of trans‐2,3‐Dihydropyridine N‐oxides and Piperidines
Authors: Andersson Hans , Gustafsson Magnus , Boström Dan , Olsson Roger , Almqvist Fredrik
Published: March 2009

Reactivity NOwn: Pyridine N‐oxides can be used for the complete regio‐ and stereoselective synthesis of trans‐substituted piperidines. The sequential addition of Grignard reagents and aldehydes or ketones to pyridine N‐oxides yields a complete regio‐ and stereoselective trans 2,3‐addition reaction in high yields, and the substituted 2,3‐dihydropyridine N‐oxide can be reduced to form 2,3‐trans‐substituted piperidines (see scheme).

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Formation of Ammonia from an Iron Nitrido Complex
Authors: Scepaniak Jeremiah J. , Young Jessica A. , Bontchev Ranko P. , Smith Jeremy M.
Published: March 2009

Radical ideas: Reaction of the iron(IV) nitrido complex [PhB(MesIm)3FeN] (see picture, Mes=2,4,6‐Me3C6H2) with TEMPO‐H (1‐hydroxy‐2,2,6,6‐tetramethylpiperidine) results in high yields of ammonia and quantitative formation of [PhB(MesIm)3Fe(tempo)]. The mechanism likely involves hydrogen‐atom transfer from TEMPO‐H to the nitrido complex. Similar reaction with the triphenylmethyl radical yields [PhB(MesIm)3FeNCPh3].

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The Fluorine‐Iminium Ion Gauche Effect: Proof of Principle and Application to Asymmetric Organocatalysis
Authors: Sparr Christof , Schweizer W. Bernd , Senn Hans Martin , Gilmour Ryan
Published: March 2009

The gauche effect that is induced upon reversible formation of an iminium ion (see structure: green F, blue N) provides a powerful method for the preorganization of transient intermediates that are central to secondary amine catalyzed processes. This phenomenon has been exploited in the design of a novel organocatalyst and is showcased in the stereoselective epoxidation of α,β‐unsaturated aldehydes.

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On the Function and Structure of Synthetically Modified Porins
Authors: Reitz Simon , Cebi Menekse , Reiß Philipp , Studnik Gregor , Linne Uwe , Koert Ulrich , Essen Lars‐Oliver
Published: March 2009

The attachment of modulators to a trimeric porin ion channel was investigated (see picture of the trimer with a crown ether modulator (orange)). The interplay of modulator and protein is essential for the conformational heterogeneity of the hybrid channel. Single‐site attachment in large pores is not sufficient to change the electrophysiological characteristics of the pores—such change requires additional noncovalent interactions or second‐site attachments.

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Effect of air flow rate on the foam fractionation of a mixture of egg white and egg yolk
Authors: Stowers Chris C. , Makarov Viktor , Walker Andy , Edwards Ross A. , Tanner Robert D.
Published: March 2009

Foam fractionation was previously shown to be an effective tool for the separation of the two visible phases in a chicken egg: egg white and the egg yolk.1 This study is a continuation of the previous study with the objective of determining the optimal separation condition in terms of air flow rate. Our results show that air flow rate is a critical operational parameter when separating these protein‐rich mixtures of egg white and egg yolk. The results show that respective concentrations of egg yolk and egg white phases change independently with respect to the air flow rate, leading to the observation that air flow rate could be exploited as a processing variable to selectively remove proteins from one section of the egg over the other section. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
An integrated analysis of prospects for advanced coal‐fired power technology in China
Authors: Li Aijun
Published: March 2009

With energy‐saving and pollution abatement policy becoming stricter and stronger, advanced coal‐fired power technology will undoubtedly play a significant role in China for the new style in industrialization of power industry. In order to forecast coal consumption for power generation from the view of Chinese economic development, firstly this paper simulates total energy consumption and loss during energy transformation in 2030 by computable general equilibrium model. Then power generation by various advanced coal‐fired power technologies such as air pollution controlling, green coal‐fired power and combined heat and power (CHP) in 2030 is estimated, thus their effects on abatement of air pollution emissions are assessed. Finally, some policy suggestions are given for developing highly efficient and super clean coal‐fired power technology in China. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Performance and characterization of irradiated poly(vinyl alcohol)/polyvinylpyrrolidone composite hydrogels used as cartilages replacement
Authors: Zheng Yudong , Huang Xiaoshan , Wang Yingjun , Xu Hong , Chen Xiaofeng
Published: March 2009

In this article, hydrogels were prepared by compounding polyvinylpyrrolidone (PVP) with poly(vinyl alcohol) (PVA), which is used as artificial cartilages, by means of repeating freezing and thawing and irradiation, for improving their mechanical and surface lubricative properties. The structures and properties, including gel content, crystallized degree, elastic modulus, and frictional coefficients of the compound hydrogels with different PVP contents and irradiative conditions, were examined and compared. The existence of PVP macromolecules interfered with the crystallization of PVA hydrogels resulted in the decrease of gel contents and elastic modulus, as well as the unstable external frictional coefficient in water. After irradiation treatment, these performances increased with irradiation intensity in lower dose ranges. The solubility and exudation of PVP in water were prevented and reduced because of the chemical crosslink of PVA and PVP, and the lubricative properties of PVA/PVP hydrogels in water were improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A sophisticated library search strategy using folksonomies and similarity matching
Authors: Pera Maria Soledad , Lund William , Ng Yiu‐Kai
Published: March 2009

Libraries, private and public, offer valuable resources to library patrons. As of today, the only way to locate information archived exclusively in libraries is through their catalogs. Library patrons, however, often find it difficult to formulate a proper query, which requires using specific keywords assigned to different fields of desired library catalog records, to obtain relevant results. These improperly formulated queries often yield irrelevant results or no results at all. This negative experience in dealing with existing library systems turns library patrons away from directly querying library catalogs; instead, they rely on Web search engines to perform their searches first, and upon obtaining the initial information (e.g., titles, subject headings, or authors) on the desired library materials, they query library catalogs. This searching strategy is an evidence of failure of today's library systems. In solving this problem, we propose an enhanced library system, which allows partial, similarity matching of (a) tags defined by ordinary users at a folksonomy site that describe the content of books and (b) unrestricted keywords specified by an ordinary library patron in a query to search for relevant library catalog records. The proposed library system allows patrons posting a query Q using commonly used words and ranks the retrieved results according to their degrees of resemblance with Q while maintaining the query processing time comparable with that achieved by current library search engines.
Tuning the Electronic Structure of Graphene by Molecular Charge Transfer: A Computational Study
Authors: Manna Arun K , Pati Swapan K
Published: March 2009

Insulating semiconducting conductors? The electronic properties of graphene can be tuned through molecular charge transfer, induced by organic electron donor (acceptor), TTF (TCNE, TCNQ), molecules. Such molecular‐charge‐transfer process has significant effects on optical and transport properties, in particular the characteristic Raman spectra of graphene.

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We have studied the modification in the electronic structure, as well as optical and transport properties of graphene induced by molecular charge transfer using ab initio density functional theory. Our results from first‐principles spin‐polarized calculations are compared with those of the available data from Raman spectroscopic studies of modified graphene systems. We find that electron donor and acceptor molecules adsorbed onto the graphene surface exhibit effective molecular charge transfer, giving rise to mid‐gap molecular levels with tuning of the band gap region near the Dirac point. The molecular charge transfer causes the stiffening or softening of the Raman G‐band frequency in graphene, and we find that it also has a significant impact on the intensity ratio of the D‐ to G‐band, corroborating experimental findings. We suggest that these charge transfer mechanisms can be probed through the low‐frequency profile of the optical conductivity.
An improved high‐performance liquid chromatography method for quantification of methotrexate polyglutamates in red blood cells of children with juvenile idiopathic arthritis
Authors: Hroch Miloš , Tuková Jana , Doležalová Pavla , Chládek Jaroslav
Published: March 2009

Methotrexate is used widely in the pharmacotherapy of juvenile idiopathic arthritis. Polyglutamates of methotrexate are active metabolites which accumulate in cells including erythrocytes. Their intracellular concentration may reflect methotrexate bioavailability and, at the same time, may serve as a bioindicator for optimization of methotrexate therapy and drug monitoring. Therefore, a simple and selective isocratic reversed phase chromatographic method with fluorescence detection (excitation/emission wavelengths of 370/463 nm) was developed which quantifies the sum of all methotrexate polyglutamates in erythrocytes as methotrexate after their enzymatic conversion with γ‐glutamylhydrolase. Separation was carried out on a Phenomenex GEMINI C18 column using a mobile phase flowing at a rate of 0.6 ml/min and consisting of a mixture (110:890:0.25 v/v) of acetonitrile, ammonium acetate buffer (0.05 m, pH=5.5) and hydrogen peroxide 30% (w/w). The method was found linear over the concentration range of 25–400 nmol/l. Its intra‐ and inter‐day precision and accuracy were characterized by coefficients of variation and relative errors less than 20%. The limits of detection and quantification achieved 10.9 and 32.9 nmol/l, respectively. The method was proved suitable for monitoring the concentration of methotrexate polyglutamates in erythrocytes of patients with juvenile idiopathic arthritis. Copyright © 2009 John Wiley & Sons, Ltd.
Stabwerke und Teilflächenbelastung nach DIN 1045‐1 und Eurocode 2 – Modelle und Anwendungen
Authors: Empelmann Martin , Wichers Marco
Published: March 2009

Stabwerkmodelle sind leistungsfähige Werkzeuge zur Beschreibung des Tragverhaltens und zur Bemessung von Stahl‐ und Spannbetonbauteilen. Ein wesentliches Anwendungsgebiet liegt in der Abbildung und Berechnung von so genannten Diskontinuitätsbereichen. Ein ebenso häufig auftretendes und mit den Stabwerkmodellen eng verknüpftes Problem ist das der Teilflächenbelastung. Im Vergleich zur Biege‐ oder Schubbemessung sind die Angaben der Normenwerke zur Anwendung von Stabwerkmodellen bzw. zum Nachweis von Teilflächenbelastungen begrenzt. Daher hat der planende Ingenieur in der Praxis die Aufgabe, auf Basis der Normenansätze geeignete Stabwerkmodelle zu finden. Der vorliegende Artikel vergleicht hierzu die wesentlichen Angaben der DIN 1045‐1 und des Eurocodes 2 (DIN EN 1992‐1‐1) bezüglich der Nutzung von Stabwerkmodellen sowie der Nachweisführung bei Teilflächenbelastungen und gibt zusätzliche Hinweise für ausgewählte Anwendungsfälle.
Der Skybarturm Neue Mitte Lehen West – Berechnung und Ausführung
Authors: Olipitz Michael , Holzleitner Regina
Published: March 2009

Der Stadtteil Lehen zählt zu den am dichtest besiedelten Gebieten von Salzburg. Hier entstand in einer Bauzeit von ca. zwölf Monaten das derzeit größte multifunktionale Bauvorhaben. Herausragend mit den weit auskragenden Bibliotheksgeschossen und der Skybar ist das Westgebäude. “Schiefe Türme benötigen einen Rückhalt” ist das Motto der Entwurfsoptimierung am Skybarturm.

Der folgende Aufsatz widmet sich den technischen Herausforderungen bei der Errichtung des Skybarturms, der zur Gänze in Stahlbeton hergestellt wurde. Mit einer Schiefstellung von 19.5° gegen die Vertikale und einer Gesamthöhe von 30 m mit einer außermittig aufgesetzten Skybar aus Stahl waren höchste Anforderungen gestellt. Die unterschiedlichen Maßnahmen zur Reduzierung der Turmverformung sowie dynamische Betrachtungen bilden den Schwerpunkt. Hybride Konstruktionen erfordern nicht nur das Zusammenspiel unterschiedlicher Materialien sondern auch der unterschiedlichen Gewerke, wie sie an Hand dieses Bauvorhabens beispielhaft vorgezeigt wurde.
Using goal setting, self‐monitoring, and feedback to increase calorie expenditure in obese adults
Authors: Donaldson Jeanne M. , Normand Matthew P.
Published: March 2009

Obesity has become a leading cause of health problems in America, many of which can be combated by increasing physical activity. As a result, interventions targeting increased physical activity are greatly needed. In this study, a package intervention consisting of goal setting, self‐monitoring, and feedback was evaluated across five participants in a multiple baseline design with a brief reversal for three of the five participants. The intervention package increased calorie expenditure for all five participants. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of response blocking and competing stimuli on stereotypic behavior
Authors: Hagopian Louis P. , Toole Lisa M.
Published: March 2009

The effects of response blocking and competing stimuli on stereotypy and aggression were examined in an analysis conducted with a young girl diagnosed with autism and intellectual disability. A functional analysis of the stereotypic behavior revealed that blocking stereotypy increased aggression. The treatment analysis revealed that the provision of competing stimuli, without response blocking resulted in decreases in both topographies. Findings suggest that the provision of competing stimuli may be less likely to occasion other behaviors than blocking. Copyright © 2009 John Wiley & Sons, Ltd.
Signaling stimulus presentation during treatment with noncontingent reinforcement: Visual versus vocal signals
Authors: Schadler John J. , Wilder David A. , Blakely Elbert
Published: March 2009

The independent effects of two signals implemented during treatment with noncontingent reinforcement (NCR) were examined. First, functional analyses showed that problem behavior exhibited by two individuals with developmental disabilities was sensitive to social positive reinforcement. A reversal design was then used to compare the effectiveness of a timer (NCR‐visual) to a vocal statement (NCR‐vocal) indicating when the stimulus would be returned in the context of a NCR procedure. Results showed that NCR reduced problem behavior for both participants. In addition, for one participant, the NCR‐visual condition reduced problem behavior to a greater degree than the NCR‐vocal condition. Copyright © 2009 John Wiley & Sons, Ltd.
Protection of dystrophic muscle cells with polyphenols from green tea correlates with improved glutathione balance and increased expression of 67LR, a receptor for (−)‐epigallocatechin gallate
Authors: Dorchies Olivier M. , Wagner Stéphanie , Buetler Timo M. , Ruegg Urs T.
Published: March 2009

Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease caused by the absence of the protein dystrophin. Because oxidative stress contributes to the pathogenesis of DMD, we investigated if a green tea polyphenol blend (GTP) and its major polyphenol (−)‐epigallocatechin gallate (EGCg), could protect muscle cell primary cultures from oxidative damage induced by hydrogen peroxide (H2O2) in the widely used mdx mouse model. On‐line fluorimetric measurements using an H2O2‐sensitive probe indicated that GTP and EGCg scavenged peroxide in a concentration‐dependent manner. A 48 h exposure to EGCg increased glutathione content but did not alter the expression of proteins involved in membrane stabilization and repair. Pretreatment of dystrophic cultures with GTP or EGCg 48 h before exposure to H2O2 improved cell survival. Normal cultures were protected by GTP but not by EGCg. 67LR, a receptor for EGCg, was seven times more abundant in dystrophic compared with normal cultures. Altogether our results demonstrate that GTP and EGCg protect muscle cells by scavenging H2O2 and by improving the glutathione balance. In addition, the higher levels of 67LR in dystrophic muscle cells compared with normal ones likely contribute to EGCg‐mediated survival. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
Chaperone‐like activities of different molecular forms of β‐casein. Importance of polarity of N‐terminal hydrophilic domain
Authors: Yousefi Reza , Shchutskaya Yulia Y. , Zimny Jaroslaw , Gaudin Jean‐Charles , Moosavi‐Movahedi Ali A. , Muronetz Vladimir I. , Zuev Yuriy F. , Chobert Jean‐Marc , Haertlé Thomas
Published: March 2009

As a member of intrinsically unstructured protein family, β‐casein (β‐CN) contains relatively high amount of prolyl residues, adopts noncompact and flexible structure and exhibits chaperone‐like activity in vitro. Like many chaperones, native β‐CN does not contain cysteinyl residues and exhibits strong tendencies for self‐association. The chaperone‐like activities of three recombinant β‐CNs wild type (WT) β‐CN, C4 β‐CN (with cysteinyl residue in position 4) and C208 β‐CN (with cysteinyl residue in position 208), expressed and purified from E. coli, which, consequently, lack the phosphorylated residues, were examined and compared with that of native β‐CN using insulin and alcohol dehydrogenase as target/substrate proteins. The dimers (β‐CND) of C4‐β‐CN and C208 β‐CN were also studied and their chaperone‐like activities were compared with those of their monomeric forms. Lacking phosphorylation, WT β‐CN, C208 β‐CN, C4 β‐CN and C4 β‐CND exhibited significantly lower chaperone‐like activities than native β‐CN. Dimerization of C208 β‐CN with two distal hydrophilic domains considerably improved its chaperone‐like activity in comparison with its monomeric form. The obtained results demonstrate the significant role played by the polar contributions of phosphorylated residues and N‐terminal hydrophilic domain as important functional elements in enhancing the chaperone‐like activity of native β‐CN. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 623–632, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
From gene mutation to protein characterization
Authors: Moffet David A.
Published: March 2009

A seven‐week “gene to protein” laboratory sequence is described for an undergraduate biochemistry laboratory course. Student pairs were given the task of introducing a point mutation of their choosing into the well studied protein, enhanced green fluorescent protein (EGFP). After conducting literature searches, each student group chose the mutation they wanted to introduce into EGFP. Students designed their sequence‐specific mutagenic primers and constructed their desired mutation. The resulting EGFP mutant proteins were expressed in E. coli, purified and characterized. This laboratory sequence connected the major concepts of molecular biology and biochemistry, while incorporating the thrill of novel discovery in an undergraduate‐level biochemistry laboratory course.