Substrate, molecular structure, and solvent effects in 2D self-assembly via hydrogen and halogen bonding

Recently, halogen···halogen interactions have been demonstrated to stabilize two-dimensional supramolecular assemblies at the liquid–solid interface. Here we study the effect of changing the halogen, and report on the 2D supramolecular structures obtained by the adsorption of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine (TBPT) and 2,4,6-tris(4-iodophenyl)-1,3,5-triazine (TIPT) on both highly oriented pyrolytic graphite and the (111) facet of a gold single crystal. These molecular systems were investigated by combining room-temperature scanning tunneling microscopy in ambient conditions with density functional theory, and are compared to results reported in the literature for the similar molecules 1,3,5-tri(4-bromophenyl)benzene (TBPB) and 1,3,5-tri(4-iodophenyl)benzene (TIPB). We find that the substrate exerts a much stronger effect than the nature of the halogen atoms in the molecular building blocks. Our results indicate that the triazine core, which renders TBPT and TIPT stiff and planar, leads to stronger adsorption energies and hence structures that are different from those found for TBPB and TIPB. On the reconstructed Au(111) surface we find that the TBPT network is sensitive to the fcc- and hcp-stacked regions, indicating a significant substrate effect. This makes TBPT the first molecule reported to form a continuous monolayer at room temperature in which molecular packing is altered on the differently reconstructed regions of the Au(111) surface. Solvent-dependent polymorphs with solvent coadsorption were observed for TBPT on HOPG. This is the first example of a multicomponent self-assembled molecular networks involving the rare cyclic, hydrogen-bonded hexamer of carboxylic groups, R66(24) synthon.

The crystal structure of eulytite Pb3BiV3O12

The crystal structure of Pb3BiV3O12 was solved using single-crystal X-ray diffraction technique. The compound crystallizes in the cubic system View the MathML source (No. 220) with eulytite structure with a = 10.7490(7) Å, V = 1241.95(14) Å3 and Z = 4. The final R1 value of 0.0198 (wR2=0.0384) was achieved for 359 independent reflections during the structure refinement. The Pb2+ and Bi3+ cations occupy the special position (16c) while the oxygen anions occupy the general position (48e) in the crystal structure. Unlike many other eulytite compounds, all the crystallographic positions are fully occupied. The structure consists of edge-shared Pb/Bi octahedra linked at the corners to independent [VO4]3− tetrahedra units, generating a eulytite-type network in the crystal lattice.

Haemodialysis work environment contributors to job satisfaction and stress: A sequential mixed methods study

Background: Haemodialysis nurses form long term relationships with patients in a technologically complex work environment. Previous studies have highlighted that haemodialysis nurses face stressors related to the nature of their work and also their work environments leading to reported high levels of burnout. Using Kanters (1997) Structural Empowerment Theory as a guiding framework, the aim of this study was to explore the factors contributing to satisfaction with the work environment, job satisfaction, job stress and burnout in haemodialysis nurses. Methods: Using a sequential mixed-methods design, the first phase involved an on-line survey comprising demographic and work characteristics, Brisbane Practice Environment Measure (B-PEM), Index of Work Satisfaction(IWS), Nursing Stress Scale (NSS) and the Maslach Burnout Inventory (MBI). The second phase involved conducting eight semi-structured interviews with data thematically analyzed. Results: From the 417 nurses surveyed the majority were female (90.9 %), aged over 41 years of age (74.3 %), and 47.4 % had worked in haemodialysis for more than 10 years. Overall the work environment was perceived positively and there was a moderate level of job satisfaction. However levels of stress and emotional exhaustion (burnout) were high. Two themes, ability to care and feeling successful as a nurse, provided clarity to the level of job satisfaction found in phase 1. While two further themes, patients as quasi-family and intense working teams, explained why working as a haemodialysis nurse was both satisfying and stressful. Conclusions: Nurse managers can use these results to identify issues being experienced by haemodialysis nurses working in the unit they are supervising.

Low temperature fluorination of sulphur compounds with elemental fluorine

Low temperature fluorination technique is adopted for fluorination of the following sulphur compounds in freon-11 medium (1) Sulphur dioxide (2) Thionyl chloride (3) Sulphuryl chloride (4) Tetrasulphur tetra nitride and (5) Sulphur bromide. All the compounds undergo oxidative fluorination to give rise to sulphur-fluorine compounds except sulphuryl chloride which resists fluorination. Sulphuryl chloride thus behaves as a good solvent medium for fluorination of other reactive compounds like elemental sulphur. Details of the experimental procedures adopted and the identification of the products will be presented.

Conformational analysis of small disulfide loops. Spectroscopic and theoretical studies on a synthetic cyclic tetrapeptide containing cystine

The conformational analysis of the synthetic peptide Boc-Cys-Pro-Val-Cys-NHMe has been carried out, as a model for small disulfide loops, in biologically active polypeptides. 'H NMR studies (270 MHz) establish that the Val(3) and Cys(4) NH groups are solvent shielded, while 13C studies establish an all-trans peptide backbone. Circular dichroism and Raman spectroscopy provide evidence for a right-handed twist of the disulfide bond. Analysis of the vicinal (JaB)c oupling constants for the two Cys residues establishes that XI - *60° for Cys(4), while some flexibility is suggested at Cys( 1). Conformational energy calculations, imposing intramolecular hydrogen bonding constraints, favor a P-turn (type I) structure with Pro(2)-Va1(3) as the corner residues. Theoretical and spectroscopic results are consistent with the presence of a transannular 4 - 1 hydrogen bond between Cys( 1) CO and Cys(4) NH groups, with the Val NH being sterically shielded from the solvent environment.

Analysis of human immunodeficiency virus type 1 drug resistance in children receiving nucleoside analogue reverse-transcriptase inhibitors plus nevirapine, nelfinavir, or ritonavir (Pediatric AIDS Clinical Trials Group 377)

In Pediatric AIDS Clinical Trials Group 377, antiretroviral therapy-experienced children were randomized to 4 treatment arms that included different combinations of stavudine, lamivudine (3TC), nevirapine (Nvp), nelfinavir (Nfv), and ritonavir (Rtv). Previous treatment with zidovudine (Zdv), didanosine (ddI), or zalcitabine (ddC) was acceptable. Drug resistance ((R)) mutations were assessed before study treatment (baseline) and at virologic failure. Zdv(R), ddI(R), and ddC(R) mutations were detected frequently at baseline but were not associated with virologic failure. Children with drug resistance mutations at baseline had greater reductions in virus load over time than did children who did not. Nvp(R) and 3TC(R) mutations were detected frequently at virologic failure, and Nvp(R) mutations were more common among children receiving 3-drug versus 4-drug Nvp-containing regimens. Children who were maintained on their study regimen after virologic failure accumulated additional Nvp(R) and 3TC(R) mutations plus Rtv(R) and Nfv(R) mutations. However, Rtv(R) and Nfv(R) mutations were detected at unexpectedly low rates.

Cultural Discourses in CEF: How Do They Relate to ELF?

Tutkielmassa selvitetään englanti lingua francana (ELF) -näkökulman ilmenemistä kulttuurin ja sen opettamisen periaatteissa. Tarkastelun kohteina ovat viimeaikaiset kielenopetuksen ohjenuoria käsittelevät ohjelmat Euroopassa ja Suomessa: Euroopan neuvoston julkaisema Eurooppalainen viitekehys ja Suomen perus- ja lukio-opetuksen uusimmat vieraiden kielten opetussuunnitelmat. Tutkielmassa sovelletaan kriittisen diskurssianalyysin kolmiportaista analyysikehystä, jonka kuvausosiossa Viitekehyksestä analysoidaan esiin kulttuurisia diskursseja, tulkintaosiossa aineistoa tarkastellaan Euroopan neuvoston kielipolitiikan osana, ja selitysosiossa sitä verrataan opetussuunnitelmista hahmotettuihin diskursseihin. Viitekehyksestä nousi esiin neljä keskeistä diskurssia: 1) kohdekulttuuri-, 2) kulttuurien monimuotoisuus-, 3) monikulttuurisuus- ja 4) oppilaskeskeisyysdiskurssit. Näistä kahdessa viimeisessä oli piirteitä, joiden voi katsoa tukevan ELF-näkökulmaa. Tällaisia olivat mm. usean kulttuurin välillä liikkuminen ja oppilaiden tarpeiden korostaminen. Sen sijaan opetussuunnitelmissa keskitytään ELF:n kannalta liian kapea-alaisesti vain äidinkielisten ja ei-äidinkielisten väliseen viestintään. ELF-lähestymistavan kannalta olisikin tärkeää ymmärtää, että kansainvälisessä viestinnässä englannin kieltä ei voi yhdistää tiettyyn kohdekulttuuriin ja että monikielitaitoisuuden ja lingua francan ei tarvitse olla ristiriidassa keskenään.

Finnen-Bashing und Bindestrich-Kapitalismus : eine diskursanalytische Untersuchung der öffentlichen Diskussion zur Nokia-Werkschließung in Bochum

Tutkielmassa tarkastellaan matkapuhelinvalmistaja Nokian Bochumin tehtaan sulkemista käsittelevää julkista keskustelua Saksan johtavissa päivälehdissä, FRANKFURTER ALLGEMEINE ZEITUNGissa ja SÜDDEUTSCHE ZEITUNGissa. Työn tarkoitus on ymmärtää, kuinka erilaiset viitekehykset vaikuttavat tapausta käsittelevän julkisen keskustelun rakentumiseen ja kuinka yksittäiset kehykset voivat vaikuttaa ensisijaiseen tapaan tulkita tehtaan sulkemista yhteiskunnallisesti merkittävänä tapahtumana. Tutkielman teoreettis-metodologisena viitekehyksenä hyödynnetään Norman Fairclough’n kriittistä diskurssianalyysia (critical discourse analysis). Analyysi jakautuu kolmeen ulottuvuuteen, keskustelun aihepiirejä hahmottavaan ja kielitieteellisestä tutkimuksesta ammentavaan tekstianalyysiin, media-tekstien tuotantoa ja tekstigenrejä tarkastelevaan diskursiivisten käytäntöjen analyysiin sekä julkisen keskustelun yhteiskunnallista merkitystä tulkitsevaan sosiaalisen kontekstin analyysiin. Varsinaisessa tutkimustyössä hyödynnetään laadullista tekstianalyysia varten kehitettyä ATLAS.ti -tietokoneohjelmaa, joka auttaa aineiston temaattisessa luokittelussa. Aihekokonaisuuksien järjestelmällinen luokittelu helpottaa lukijaa ymmärtämään tutkijan tekemiä tulkintoja ja johtopäätöksiä. Diskurssianalyyttisen tarkastelun perusteella tutkittavan julkisen keskustelun diskursiivisen muodos-telman voidaan katsoa rakentuvan seitsemästä elementistä, diskursseista (1) solidaarisuus tehtaan työntekijöitä kohtaan, (2) yrityksen mielivaltainen toiminta, (3) poliitikkojen uskottavuus, (4) globalisaatiokeskustelu, (5) talousulottuvuus, (6) Suomi-konteksti ja puutteet yrityksen viestinnässä sekä elementistä (7) julkisen keskustelun kerronnallinen rakenne. Julkisen keskustelun yhteiskunnallista merkitystä tarkastellaan kolmen ulottuvuuden kautta, jotka perus-tuvat Faircloughn käsitykseen diskurssin taloudellisista, poliittisista ja kulttuurisista vaikutuksista. Nokia-ulottuvuus arvioi yrityksen imagon ja Suomi-kuvan suhdetta, Saksa-ulottuvuus pohtii demokratian toteu-tumista sekä politiikkaa käsittelevää uutisointia Saksassa ja globalisaatio-ulottuvuus pohtii eurooppalaisen ja globaalin mediajulkisuuden eroja sekä mahdollisuuksia vaikuttaa tai osallistua julkiseen keskusteluun ja toimintaan kansalaisena tai kuluttajana. Suomalaisten toimijoiden niukka osallistuminen Saksassa käytyyn keskusteluun ja toimijoiden yksi-puoliset kommentit saattavat vahvistaa suomalaista liiketoimintaa ja suomalaisuutta koskevia stereo-typioita Saksassa. Julkisen keskustelun pessimistinen luonne saattaa vahvistaa lukijoiden skeptistä suhtautumista poliittiseen toimintaan. Globalisaation monimutkaisten korrelaatiosuhteiden esittäminen voi aiheuttaa ongelmia myös johtaville päivälehdille, jotka joutuvat tasapainottelemaan kansallisen, eurooppalaisen ja globaalin uutisoinnin välillä.

Representation of functional dependencies in relational databases using linear graphs

Functional dependencies in relational databases are investigated. Eight binary relations, viz., (1) dependency relation, (2) equipotence relation, (3) dissidence relation, (4) completion relation, and dual relations of each of them are described. Any one of these eight relations can be used to represent the functional dependencies in a database. Results from linear graph theory are found helpful in obtaining these representations. The dependency relation directly gives the functional dependencies. The equipotence relation specifies the dependencies in terms of attribute sets which functionally determine each other. The dissidence relation specifies the dependencies in terms of saturated sets in a very indirect way. Completion relation represents the functional dependencies as a function, the range of which turns out to be a lattice. Depletion relation which is the dual of the completion relation can also represent functional dependencies and similarly can the duals of dependency, equipotence, and dissidence relations. The class of depleted sets, which is the dual of saturated sets, is defined and used in the study of depletion relations.

Adducts of Silicon Tetrafluoride with Aminocyclophosphazenes : Synthesis and Characterization

Stable solid adducts of SiF4 with the following aminocyclophosphazenes have been synthesized : N3P3(NHCH2CH2NH)(NMe2)4(,1 ) ; N3P3(NHCH2CH2NH)C14(,2 ) ; N3P3(NMe2)4C12(,3 ) ; N3P3(NHMe),,(4) ; N3P3(NMe2),, (5) ; N,P,(NHMe),, (6) ; N4P4(NMe2),, (7) ; and N,P,(NHBu'),, (8). They have been characterized by elemental analysis, i.r., and n.m.r. ( H, 31 P, and 19F) spectroscopy. The composition of the adducts varies depending on the ring size and also on the nature of the substituents on the phosphorus. The number of SiF4 molecules accommodated by the ligands is larger when the ring size is large, while it is less when the ligands contain chlorine. Except in the cases of ligands (1) and (2), bonding is through the ring nitrogens. With (I), both exocyclic nitrogen and ring nitrogen atoms, and with (2) only exocyclic nitrogen atoms, participate in co-ordination. In these two cases the silicon is six-co-ordinated, while in the other cases it is five-co-ordinated.

The ontogeny of serum immunoreactive pancreatic lipase and cationic trypsinogen in the premature human infant

We evaluated the development of the exocrine pancreas in 16 healthy preterm infants (29.3 ± 1.6 weeks). The infants were fed breast milk with formula supplements (n=8) or formula alone (n=8). Growth was monitored weekly for 12 weeks then at 3, 6, 9, 12 months. At the same intervals sera were determined for pancreatic lipase and cationic trypsinogen. In addition, cord blood samples were analysed from another 33 preterm (27.6 ± 5.2 weeks) and 75 healthy full-term infants. Serum pancreatic lipase in the cord blood of term (3.7 ± 0.4 μg/l) and preterm infants (1.8 ± 0.2 μg/l) was significantly below values reported for older children (10.5 ± 0.9 μg/l; p < 0.001). In the preterm infant, serum lipase was also significantly lower than values obtained at term (p < 0.001). At birth, serum trypsinogen for preterm (16.8 ± 1.3 μg/l) and term infants (23.3 ± 1.9 μg/l) were below those for older children (31.4 ± 3.7 μg/l; p < 0.05). Over the first 3 weeks of life, serum lipase and trypsinogen increased significantly. From 3 weeks to 12 months of age, serum trypsinogen values remained unchanged, but serum lipase increased dramatically after 10 weeks of age. Thus, at 6 and 12 months of age, the preterm infants had significantly higher serum lipase values than infants of the same age born at term. These two pancreatic enzymes appear to show independent age-related maturation in infants born before term. The rate of maturation of lipase appears to be accelerated by exposure to the extrauterine environment.

Photosynthetic responses of seven tropical seagrasses to elevated seawater temperature

This study uses chlorophyll a fluorescence to examine the effect of environmentally relevant (1-4 h) exposures of thermal stress (35-45 [deg]C) on seagrass photosynthetic yield in seven tropical species of seagrasses. Acute response of each tropical seagrass species to thermal stress was characterised, and the capacity of each species to tolerate and recover from thermal stress was assessed. Two fundamental characteristics of heat stress were observed. The first effect was a decrease in photosynthetic yield (Fv / Fm) characterised by reductions in F and Fm'. The dramatic decline in Fv / Fm ratio, due to chronic inhibition of photosynthesis, indicates an intolerance of Halophila ovalis, Zostera capricorni and Syringodium isoetifolium to ecologically relevant exposures of thermal stress and structural alterations to the PhotoSystem II (PSII) reaction centres. The decline in Fm' represents heat-induced photoinhibition related to closure of PSII reaction centres and chloroplast dysfunction. The key finding was that Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis and Thalassia hemprichii were more tolerant to thermal stress than H. ovalis, Z. capricorni and S. isoetifolium. After 3 days of 4 h temperature treatments ranging from 25 to 40 [deg]C, C. rotundata, C. serrulata and H. uninervis demonstrated a wide tolerance to temperature with no detrimental effect on Fv / Fm' qN or qP responses. These three species are restricted to subtropical and tropical waters and their tolerance to seawater temperatures up to 40 [deg]C is likely to be an adaptive response to high temperatures commonly occurring at low tides and peak solar irradiance. The results of temperature experiments suggest that the photosynthetic condition of all seagrass species tested are likely to suffer irreparable effects from short-term or episodic changes in seawater temperatures as high as 40-45 [deg]C. Acute stress responses of seagrasses to elevated seawater temperatures are consistent with observed reductions in above-ground biomass during a recent El Nino event.

Congruence in QTL for adventitious rooting in Pinus elliottii x Pinus caribaea hybrids resolves between and within-species effects

Targeting between-species effects for improvement in synthetic hybrid populations derived from outcrossing parental tree species may be one way to increase the efficacy and predictability of hybrid breeding. We present a comparative analysis of the quantitative trait loci (QTL) which resolved between from within-species effects for adventitious rooting in two populations of hybrids between Pinus elliottii and P. caribaea, an outbred F1 (n=287) and an inbred-like F2 family (n=357). Most small to moderate effect QTL (each explaining 2-5% of phenotypic variation, PV) were congruent (3 out of 4 QTL in each family) and therefore considered within-species effects as they segregated in both families. A single large effect QTL (40% PV) was detected uniquely in the F2 family and assumed to be due to a between-species effect, resulting from a genetic locus with contrasting alleles in each parental species. Oligogenic as opposed to polygenic architecture was supported in both families (60% and 20% PV explained by 4 QTL in the F 2 and F1 respectively). The importance of adventitious rooting for adaptation to survive water-logged environments was thought in part to explain oligogenic architecture of what is believed to be a complex trait controlled by many hundreds of genes.

Conformations of the amino aterminal tetrapeptide of emerimicins and antiamoebins in solution and in the solid state

The conformations of Boc-l-Phe-(AiB)3-OH (1) and Boc-l-Phe-(Aib)3-OMe (2) which correspond to the amino terminal sequence of the emerimicins and antiamoebins have been studied in solution using 270 MHz 1H n.m.r. In dimethyl sulphoxide solution both peptides show the presence of two strongly solvent shielded Aib NH groups, consistent with a consecutive β-turn conformation, involving the Aib(3) and Aib(4) NH groups in intramolecular 4 → I hydrogen bonds. This folded conformation is maintained for 2 in chloroform solution. Nuclear Overhauser effect studies provide evidence for a Type II Phe-Aib β-turn. An X-ray diffraction study of Boc-(d,l)-Phe-(Aib)3-OH establishes a single type III(III′) β-turn conformation with Aib(2)-Aib(3) as the corner residues. A single intramolecular 4 → I hydrogen bond between Phe(I) CO and Aib(4) NH groups is observed in the crystal. The solution conformation may incorporate a consecutive type II-III′ structure for the Phe(1)-Aib(2)-Aib(3) segment, with the initial type II β-turn being destabilized by intermolecular interactions in the solid state.

Sekä että : Ironia koherenssina ja inkoherenssina

The interpretation of irony in this study is seen as being crucially dependent on the notion of coherence. Coherence depends on a complex interplay of contextual features, which is why all interpretations must be seen as socio-cultural processes. An utterance is perceived as coherent if it makes sense and if it hangs together. Incoherent utterances can result in an ironic interpretation; however, the incoherence must also be perceived as being intentional, and intentionality in turn is a sign of the ironist's rejecting stance. The study does not encompass the notion of irony of fate nor situational irony that is unintentional. Irony is defined in this study as a combination of five components. It is seen as (1) a negative attitude that reflects (2) the intention of the ironist, and (3) has a target and most often (4) a victim too. Essential to irony is its fifth component, the fact that one or more of these four components must be inferred from co- or context. The componential definition of irony is crucial in deciding whether an interpretation is ironic or not, and the definition makes it possible to discern the differences as well as the similarities between different kinds of irony. The method of the study is experimental: 12 Finnish newspaper texts that could be considered to be ironic were interpreted by 107 informants. The interpretation of one of the texts was based on unelicited feedback given by readers of a weekly magazine. The responses were analyzed to determine (a) whether the texts were perceived as being coherent or incoherent and (b) whether the informants appealed to any of the five components of irony. The results of the analyses of the informants' responses indicate that differences between the ironic and non-ironic interpretations of the texts can be explained in terms of whether or not the informant regarded the text as being coherent. The thesis also discusses the shortcomings of other accounts of irony: the Gricean theory of conversational implicature, speech act theory, irony as rhetoric, irony as pretense, irony as echoic mention, and irony as framing. In contrast to these other accounts, the study focuses on irony as a textual phenomenon and underlines the importance of socio-cultural context in the interpretation of irony. Key words: irony, coherence, incoherence, the componential definition of irony, interpretation of linguistic utterances.