A new method for generation of quasi-periodic structures withn fold axes: Application to five and seven folds

A new geometrical method for generating aperiodic lattices forn-fold non-crystallographic axes is described. The method is based on the self-similarity principle. It makes use of the principles of gnomons to divide the basic triangle of a regular polygon of 2n sides to appropriate isosceles triangles and to generate a minimum set of rhombi required to fill that polygon. The method is applicable to anyn-fold noncrystallographic axis. It is first shown how these regular polygons can be obtained and how these can be used to generate aperiodic structures. In particular, the application of this method to the cases of five-fold and seven-fold axes is discussed. The present method indicates that the recursion rule used by others earlier is a restricted one and that several aperiodic lattices with five fold symmetry could be generated. It is also shown how a limited array of approximately square cells with large dimensions could be detected in a quasi lattice and these are compared with the unit cell dimensions of MnAl6 suggested by Pauling. In addition, the recursion rule for sub-dividing the three basic rhombi of seven-fold structure was obtained and the aperiodic lattice thus generated is also shown.

Coexistence curve of acetonitrile and cyclohexane liquid system

The paper reports a detailed determination of the coexistence curve for the binary liquid system acetonitrile+cyclohexane, which have very closely matched densities and the data points get affected by gravity only for t=(Tc−T)/ Tc[approximately-equal-to]10−6. About 100 samples were measured over the range 10−6liquids. The extrapolation properties of the Wegner expansion procedure is somewhat inferior to the extrapolation obtained using a renormalization group (RG) crossover expansion. The use of the new variables proposed by Johnston et al. and Vnuk in making the coexistence curve appear symmetric in the new variables is pointed out. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

Analyzing hysteresis behavior of capacitance-voltage characteristics of IZO/C₆₀/pentacene/Au diodes with a hole-transport electron-blocking polyterpenol layer by electric-field-induced optical second-harmonic generation measurement

By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, we analyzed hysteresis behavior of capacitance-voltage (C-V) characteristics of IZO/polyterpenol (PT)/C₆₀/pentacene/Au diodes, where PT layer is actively working as a hole-transport electron-blocking layer. The EFISHG measurement verified the presence of interface accumulated charges in the diodes, and showed that a space charge electric field from accumulated excess electrons (holes) that remain at the PT/C₆₀ (C₆₀/pentacene) interface is responsible for the hysteresis loop observed in the C-V characteristics.

Investigation of interfacial charging and discharging in double-layer pentacene-based metal-insulator-metal device with polyterpenol blocking layer using electric field induced second harmonic generation

Time-resolved electric field induced second harmonic generation technique was used to probe the carrier transients within double-layer pentacene-based MIM devices. Polyterpenol thin films fabricated from non-synthetic environmentally sustainable source were used as a blocking layer to assist in visualisation of single-species carrier transportation during charging and discharging under different bias conditions. Results demonstrated that carrier transients were comprised of charging on electrodes, followed by carrier injection and charging of the interface. Polyterpenol was demonstrated to be a sound blocking material and can therefore be effectively used for probing of double-layer devices using EFISHG.

Rapid microsatellite marker development for African mahogany ( Khaya senegalensis, Meliaceae) using next-generation sequencing and assessment of its intra-specific genetic diversity.

Khaya senegalensis (African mahogany or dry-zone mahogany) is a high-value hardwood timber species with great potential for forest plantations in northern Australia. The species is distributed across the sub-Saharan belt from Senegal to Sudan and Uganda. Because of heavy exploitation and constraints on natural regeneration and sustainable planting, it is now classified as a vulnerable species. Here, we describe the development of microsatellite markers for K. senegalensis using next-generation sequencing to assess its intra-specific diversity across its natural range, which is a key for successful breeding programs and effective conservation management of the species. Next-generation sequencing yielded 93943 sequences with an average read length of 234bp. The assembled sequences contained 1030 simple sequence repeats, with primers designed for 522 microsatellite loci. Twenty-one microsatellite loci were tested with 11 showing reliable amplification and polymorphism in K. senegalensis. The 11 novel microsatellites, together with one previously published, were used to assess 73 accessions belonging to the Australian K. senegalensis domestication program, sampled from across the natural range of the species. STRUCTURE analysis shows two major clusters, one comprising mainly accessions from west Africa (Senegal to Benin) and the second based in the far eastern limits of the range in Sudan and Uganda. Higher levels of genetic diversity were found in material from western Africa. This suggests that new seed collections from this region may yield more diverse genotypes than those originating from Sudan and Uganda in eastern Africa.

Generation of hydrogen peroxide on oxidation of NADH by hepatic plasma membranes

The oxidation of NADH by mouse liver plasma membranes was shown to be accompanied by the formation of H2O2. The rate of H2O2 formation was less than one-tenth the rate of oxygen uptake and much slower than the rate of reduction of artificial electron acceptors. The optimum pH for this reaction was 7.0 and theK m value for NADH was found to be 3×10–6 M. The H2O2-generating system of plasma membranes was inhibited by quinacrine and azide, thus distinguishing it from similar activities in endoplasmic reticulum and mitochondria. Both NADH and NADPH served as substrates for plasma membrane H2O2 generation. Superoxide dismutase and adriamycin inhibited the reaction. Vanadate, known to stimulate the oxidation of NADH by plasma membranes, did not increase the formation of H2O2. In view of the growing evidence that H2O2 can be involved in metabolic control, the formation of H2O2 by a plasma membrane NAD(P)H oxidase system may be pertinent to control sites at the plasma membrane.

Ranking of Prospective New Generation Location for a Power Network in a Deregulated System

In developing countries high rate of growth in demand of electric energy is felt, and so the addition of new generating units becomes necessary. In deregulated power systems private generating stations are encouraged to add new generations. Finding the appropriate location of new generator to be installed can be obtained by running repeated power flows, carrying system studies like analyzing the voltage profile, voltage stability, loss analysis etc. In this paper a new methodology is proposed which will mainly consider the existing network topology into account. A concept of T-index is introduced in this paper, which considers the electrical distances between generator and load nodes.This index is used for ranking significant new generation expansion locations and also indicates the amount of permissible generations that can be installed at these new locations. This concept facilitates for the medium and long term planning of power generation expansions within the available transmission corridors. Studies carried out on a sample 7-bus system, EHV equivalent 24-bus system and IEEE 39 bus system are presented for illustration purpose.

Reciprocal and advanced generation hybrids between Corymbia citriodora and C-torelliana: forestry breeding and the risk of gene flow

Corymbia F1 hybrids have high potential for plantation forestry; however, little is known of their reproductive biology and potential for genetic pollution of native Corymbia populations. This study aims to quantify the influence of reproductive isolating barriers on the success of novel reciprocal and advanced generation Corymbia hybrids. Two maternal taxa, Corymbia citriodora subsp. citriodora and Corymbia torelliana, were pollinated using five paternal taxa, C. citriodora subsp. citriodora, C. torelliana, one C. torelliana x C. citriodora subsp. citriodora hybrid and two C. torelliana x C. citriodora subsp. variegata hybrids. Pollen tube, embryo and seed development were assessed. Reciprocal hybridisation between C. citriodora subsp. citriodora and C. torelliana was successful. Advanced generation hybrids were also created when C. citriodora subsp. citriodora or C. torelliana females were backcrossed with F1 hybrid taxa. Prezygotic reproductive isolation was identified via reduced pollen tube numbers in the style and reduced numbers of ovules penetrated by pollen tubes. Reproductive isolation was weakest within the C. citriodora subsp. citriodora maternal taxon, with two hybrid backcrosses producing equivalent capsule and seed yields to the intraspecific cross. High hybridising potential was identified between all Corymbia species and F1 taxa studied. This provides opportunities for advanced generation hybrid breeding, allowing desirable traits to be amplified. It also indicates risks of gene flow between plantation and native Corymbia populations.

Elastic constants of galena down to liquid helium temperatures

The elastic constants of single crystal galena have been determined from the measured ultrasonic velocities down to liquid helium temperature. A cryostat incorporating an arrangement to inject the liquid bonding material at low temperature is described. At 5 K, the values of elastic constants are C11=14.90, C12=3.51 and C44=2.92×1010 N/m2.

Establishing the next generation at work: Leader generativity as a moderator of the relationships between leader age, leader-member exchange, and leadership success

In this study, the authors investigated leader generativity as a moderator of the relationships between leader age, leader-member exchange, and three criteria of leadership success (follower perceptions of leader effectiveness, follower satisfaction with leader, and follower extra effort). Data came from 128 university professors paired with one research assistant each. Results showed positive relationships between leader age and leader generativity, and negative relationships between leader age and follower perceptions of leader effectiveness and follower extra effort. Consistent with expectations based on leadership categorization theory, leader generativity moderated the relationships between leader age and all three criteria of leadership success, such that leaders high in generativity were better able to maintain high levels of leadership success at higher ages than leaders low in generativity. Finally, results of mediated moderation analyses showed that leader-member exchange quality mediated these moderating effects. The findings suggest that, in combination, leader age and the age-related construct of generativity importantly influence leadership processes and outcomes. © 2011 American Psychological Association.

Microbial life and deposits in paper machine circuits

Väitöskirjani käsittele mikrobien ja erilaisten kemikaalien rooleja saostumien ja biofilmien muodostumisessa paperi- ja kartonkikoneilla. "Saostuma" tässä työssä tarkoittaa kiinteän aineen kertymää konepinnoille tai rajapinnoille konekierroissa, jotka on tarkoitettu massasulppujen, lietteiden, vesien tai ilman kuljetukseen. Saostumasta tulee "biofilmi" silloin kun sen oleellinen rakennekomponentti on mikrobisolut tai niiden tuotteet. Väitöstyöni työhypoteesina oli, että i. tietämys saostumien koostumuksesta, sekä ii. niiden rakenteesta, biologisista, fysikaalis-kemiallisista ja teknisistä ominaisuuksista ohjaavat tutkijaa löytämään ympäristöä säästäviä keinoja estää epätoivottujen saostumien muodostus tai purkaa jo muodostuneita saostumia. Selvittääkseni saostumien koostumista ja rakennetta käytin monia erilaisia analytiikan työkaluja, kuten elektronimikroskopiaa, konfokaali-laser mikroskopiaa (CLSM), energiadispersiivistä röntgenanalyysiä (EDX), pyrolyysi kaasukromatografiaa yhdistettynä massaspektrometriaan (Py-GCMS), joninvaihtokromatografiaa, kaasukromatografiaa ja mikrobiologisia analyysejä. Osallistuin aktiivisesti innovatiivisen, valon takaisinsirontaan perustuvan sensorin kehittämistyöhön, käytettäväksi biofilmin kasvun mittaukseen suoraan koneen vesikierroista ja säiliöistä. Työni osoitti, että monet paperinvalmistuksessa käytetyistä kemikaaleista reagoivat keskenään tuottaen orgaanisia tahmakerroksia konekiertojen teräspinnoille. Löysin myös kerrostumia, jotka valomikroskooppisessa tarkastelussa oli tulkittu mikrobeiksi, mutta jotka elektronimikroskopia paljasti alunasta syntyneiksi, alumiinihydroksidiksi joka saostui pH:ssa 6,8 kiertokuitua käyttävän koneen viiravesistä. Monet paperintekijät käyttävät vieläkin alunaa kiinnitysaineena vaikka prosessiolot ovat muuttuneet happamista neutraaleiksi. Sitä pidetään paperitekijän "aspiriinina", mutta väitöstutkimukseni osoitti sen riskit. Löysin myös orgaanisia saostumia, joiden alkuperä oli aineiden, kuten pihkan, saippuoituminen (kalsium saippuat) niin että muodostui tahmankasvua ylläpitävä alusta monilla paperi- ja kartonkikoneilla. Näin solumuodoiltaan Deinococcus geothermalista muistuttavia bakteereita kasvamassa lujasti teräskoepalojen pintaan kiinnittyneinä pesäkkeinä, kun koepaloja upotettiin paperikoneiden vesikiertoihin. Nämä deinokokkimaiset pesäkkeet voivat toimia jalustana, tarttumisalustana muiden mikrobien massoille, joka selittäisi miksi saostumat yleisesti sisältävät deinokokkeja pienenä, muttei koskaan pääasiallisena rakenneosana. Kun paperikoneiden käyttämien vesien (raakavedet, lämminvesi, biologisesti puhdistettu jätevesi) laatua tutkitaan, mittausmenetelmällä on suuri merkitys. Koepalan upotusmenetelmällä todettu biofilmikasvu ja viljelmenetelmällä mitattu bakteerisaastuneisuus korreloivat toisiinsa huonosti etenkin silloin kun likaantumisessa oli mukana rihmamaiseti kasvavia bakteereja. Huoli ympäristöstä on pakottanut paperi- ja kartonkikoneiden vesikiertojen sulkemiseen. Vesien kierrätys ja prosessivesien uudelleenkäyttö nostavat prosessilämpötilaa ja lisäävät koneella kiertävien kolloidisten ja liuenneiden aineiden määriä. Tutkin kiertovesien pitoisuuksia kolmessa eriasteisesti suljetussa tehtaassa, joiden päästöt olivat 0 m3, 0,5 m3 ja 4 m3 jätevettä tuotetonnia kohden, perustuen puhdistetun jäteveden uudelleen käyttöön. Nollapäästöisellä tehtaalla kiertovesiin kertyi paljon orgaanisesti sidottua hiiltä (> 10 g L-1), etenkin haihtuvina happoina (maito-, etikka-, propioni- ja voi-). Myös sulfaatteja, klorideja, natriumia ja kalsiumia kertyi paljon, > 1 g L-1 kutakin. Pääosa (>40%) kaikista bakteereista oli 16S rRNA geenisekvenssianalyysien tulosten perusteella sukua, joskin etäistä (< 96%) ainoastaan Enterococcus cecorum bakteerille. 4 m3 päästävältä tehtaalta löytyi lisäksi Bacillus thermoamylovorans ja Bacillus coagulans. Tehtaiden saostumat sisälsivät arkkeja suurina pitoisuuksina, ≥ 108 g-1, mutta tunnistukseen riittävää sekvenssisamanlaisuutta löytyi vain yhteen arkkisukuun, Methanothrix. Tutkimustulokset osoittivat että tehtaan vesikiertojen sulkeminen vähensi rajusti mikrobiston monimuotoisuutta, muttei estänyt liuenneen aineen ja kiintoaineen mineralisoitumista.

Multiple liquid-crystals and NMR

The use of more than one liquid crystal solvents to determine molecular structure and conformation is discussed. Liquid crystals of similar and opposite signs of diamagnetic anisotropies are considered separately since they lead to different novel applications. Advantages of such experiments over those employing single solvents are pointed out with illustrative examples.