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1

Alcune osservazioni sulle cause di tenuta del settore del franchising nelle fasi recessive  

Microsoft Academic Search

La ricerca esamina le imprese che operano in franchising attraverso microdati raccolti da Assofranchising, la principale associazione italiana nel campo del franchising. Mediante tecniche esplorative e multivariate si dimostra che, ceteris paribus, un aumento della scala delle reti, basata sulla crescita delle risorse umane e materiali, ha un effetto positivo sull’efficienza aziendale attraverso il miglioramento di indicatori strategici di produttività.

Antonio Bernardi

2011-01-01

2

Osservazioni sull'innervazione della cute fetale con particolare riguardo alle dita  

Microsoft Academic Search

Riassunto Gli autori riferiscono brevemente alcune delle osservazioni istochimiche compiute sulla cute delle dita di feti di età da 4 a 32 settimane impiegando la tecnica diKoelle eFriedenwald, modificata daGomori, per la dimostrazione delle colinesterasi; tecnica rivelatasi eccellente per mettere in chiara evidenza la rete nervosa sia superficiale che profonda della cute fetale.

F. Serri; W. Montagna; H. Mescon

1962-01-01

3

Metriche per la valutazione delle strategie di dialogo nei sistemi di dialogo parlato  

Microsoft Academic Search

In questo articolo è presentato un insieme di metriche da utilizzare per la valutazione di differenti strategie di gestione del dialogo in un sistema di riconoscimen - to vocale in tempo reale. L'insieme di metriche propo - sto cerca di offrire osservazioni utili alla valutazione di come particolari scelte, fatte a livello di gestione del dialogo possono influenzare la qualità

M. Danieli; E. Gerbino

4

Programma di fotometria CCD su minimi di binarie a eclisse. Osservazioni di OO Aquilae  

NASA Astrophysics Data System (ADS)

A campaign of CCD photometry aimed at detecting minima of eclipsing binaries is proposed. A "test" list of eclipsing binaries is presented. It contains relatively bright sources, with a possible comparison star in the typical field of a CCD applied to 15-40 cm telescopes. The possibility to perform useful photometry on variable stars using webcams is discussed, presenting the results obtained on V745 Cas. One time of minimum of the eclipsing binary OO Aql is also presented together with its updated O-C diagram.

Marino, Giuseppe

2006-06-01

5

Movimenti atmosferici attorno alla Grande Macchia Rossa di Giove: osservazioni e commenti  

NASA Astrophysics Data System (ADS)

The Italian Union of Amateur Astronomers (UAI) has a large collection of digital values of rotation periods of features on Jupiter's atmosphere. In this paper, the data obtained for visible features around the Great Red Spot are used to examine the nature of the Spot itself. It results (as it is well known) that the Taylor's column hypothesis is not acceptable. The data show that the Spot shares a large velocity field like the large atmospheric storms at low Earth latitudes. The approximate value of the vertical velocity inside the atmosphere is estimated. It is deduced that on large scale the Jovian atmosphere is stratified like, for example, water and oil. This condition is described by the hydrostatic equilibrium.

Braga, Raffaello

2003-03-01

6

Ambienti Circumstellari ed Interstellari di Supernovae di vario Tipo ed Applicazioni Astrofisiche  

NASA Astrophysics Data System (ADS)

Nella presente tesi vengono studiati gli ambienti circumstellari ed interstellari di supernovae (anche SNe; singolare SN) di vario tipo. In particolare si descrivono alcune applicazioni astrofisiche, relative a questi ambienti, che permettono di desumere informazioni sui sistemi stellari progenitori delle supernovae o di determinare le distanze a tali oggetti. L' emissione radio da supernovae, prodotta nell' ambiente circumstellare ad opera dell'interazione idrodinamica del gas di SN con l' ambiente circostante, puo' essere impiegata come mezzo di indagine del sistema di pre-supernova. In particolare si e' introdotta l'idea che tale emissione possa essere impiegata nel caso delle SNe di tipo Ia come test dei sistemi progenitori di tipo simbiotico. Il test e' stato effettuato sulla SN 1986G, per la quale avevamo ottenuto limiti superiori a lunghezze d'onda radio. Nel caso che un sistema simbiotico sia responsabile di una SN Ia, l'interazione tra l' ejecta e una shell circumstellare origina, in un'epoca molto prossima al massimo di luce, un'emissione radio rivelabile con strumenti tipo Very Large Array. Inoltre l'emissione radio fornisce informazioni circa gli stadi di pre-supernova nel caso di altri tipi di supernova. In questo lavoro di tesi vengono presentati i risultati ottenuti nel caso delle SNe di tipo II 1984E e 1986E. Queste due SNe non mostrano emissione radio: la prima, in prossimita del massimo ottico, stava interagendo con una shell circumstellare prodotta da un episodio di perdita di massa di breve durata in fase di pre-supernova; la seconda, invece e' la prima SN ``vecchia'' ad essere rivelata nell' ottico ma non nel radio (l' oggetto non ha ancora iniziato la fase di supernova remnant ed emette radiazione ottica prodotta ancora per interazione circumstellare). In ambiente circum-interstellare, gli echi di luce, prodotti dallo scattering della luce della supernova ad opera della polvere presente, possono essere utilizzati per determinare le distanze extra-galattiche per via puramente geometrica (Sparks 1994; 1996). Osservazioni da terra, in imaging e polarimetria, sono state utilizzate per selezionare un numero promettente di candidati, che mostrano emissione visibile alla posizione della supernova. Tali candidati sono promettenti non solo per l' applicazione del metodo descritto ma anche per dedurre informazioni circa le supernovae medesime e le relative popolazioni stellari.

Boffi, Francesca R.

7

STIMA DELLA VITA LCF E TMF DI ACCIAIO AUSTENITICO: CONFRONTO ANALITICO SPERIMENTALE DI MODELLI DI DANNEGGIAMENTO  

Microsoft Academic Search

Sommario La vita di un materiale metallico in presenza di so llecitazioni meccaniche e termiche variabili nel tempo in campo plastico può essere investigato mediante modelli di danneggiamento descritti dettagliatament e in letteratura. Per la calibrazione dei modelli costitutivi e di danneggia mento è necessario un numero di prove di caratterizzazione, standard e non, dipende nti dal livello di approfondimento

C. Delprete; R. Sesana; A. Vercelli

8

Drivers di valore, criteri di port selection e strategie di sviluppo portuale nel settore crocieristico  

Microsoft Academic Search

Drivers di valore, criteri di port selection e strategie di sviluppo portuale nel settore crocieristico (di Lara Penco) - Abstract: Con il presente contributo, si è tentato di esaminare i possibili contenuti delle strategie che un porto può adottare nel business del trasporto passeggeri su nave da crociera al fine di rendersi maggiormente attrattivo nei confronti delle compagnie crocieristiche. Volendo

Lara Penco

2001-01-01

9

ANALISI DI STABILITÀ DEL MODELLO DI UN AUTOVETTURA  

Microsoft Academic Search

Sommario Il lavoro è incentrato sull'analisi di biforcazione di un modello di vettura che sta affrontando una curva. Il modello ha 2 gradi di libertà, e le sue equazioni contengono le non linearità dovute alla curve caratteristiche degli pneumatici. Dopo aver analizzato l'andamento degli equilibri al variare di un parametro tramite metodi di continuazione, viene fatta l'analisi di biforcazione al

Giampiero Mastinu; Fabio Della Rossa; Vitaliano Nobile

10

Esiti di stroke e di frattura di femore a confronto: aspetti funzionali, qualitá di vita e costi riabilitativi  

Microsoft Academic Search

Introduzione Stroke e frattura di femore sono le due patologie più frequente- mente trattate nella riabilitazione intensiva ospedaliera. Con il nostro lavoro vogliamo dare un contributo all'analisi della situazione domiciliare a medio termine dall'evento acuto dei pazienti con esiti di stroke e dei pazienti con postumi di frattura di femore sotto quattro principali aspetti: funzionale, della qualità di vita, dei

A. BOCCIGNONE; C. FERRARO; S. VALARINI; G. PIGNATARO; A. C. FRIGO

11

Società italiana di flebologia.  

PubMed

tia venosa, con l'inizio dell'incedere bipede antropoide, nel periodo oligocenico: un graffito rupestre dell'Ennedi nel Sahara, risalente a tale epoca, rappresenta l'arto inferiore di un cacciatore chiaramente edematoso rispetto al contro-laterale. E che si riproducessero gli effetti di una malattia su una roccia, testimonia l'importanza attribuita al fenomeno per la probabile diffusione della patologia : potremmo individuare in questo i germi della nascita di un primo pensiero medico (flebologico). Cardine della odierna terapia flebologica, la correzione della stasi venosa con il bendaggio anelastico dell'arto inferiore, ma già nel 2600 a.C. Imhotep, grande chirurgo egizio, nel suo trattato di chirurgia raccomandava "il bendaggio ad X dell'arto in presenza di varici e piaghe delle gambe", più che la chirurgia. E possiamo individuare in un grande bassorilievo greco in marmo, ex-voto del IV° secolo a.C., il primo "stemma" ufficiale della Flebologia: vi è scolpita una grossa gamba con safena interna varicosa ! Nel Corpus Hippocraticum, grande compendio di tutta la medicina antica fino al IV° secolo a.C., il grande medico Koos sconsigliava la chirurgia delle varici; preconizzava invece punture ravvicinate delle vene lungo il decorso varicoso, così da conseguirne la totale obliterazione: venivano così proposte le prime idee della futura scleroterapia! E ancora, nel libro sulle ulcere, Ippocrate raccomandava il bendaggio compressivo delle gambe. Nel 400 d.C. Oribasio di Pergamo, sintetizzando tutto il sapere greco e romano fino ai suoi giorni in 70 volumi, descrisse in uno di questi con grande correttezza il suo intervento chirurgico delle varici: dall'isolamento della safena alla legatura e sezione della stessa e delle sue collaterali. Nel 600 d.C. Paolo di Eghina, nel sesto dei suoi sette libri di medicina, sistematizzò la safenectomia così come pedissequamente riproposta da Trendelemburg nel '900. Tanti secoli di "cultura flebologica" non potevano lasciare indifferenti un manipolo di giovani medici flebologi, "peones dell'angiologia" : così fondammo la SOCIETÀ ITALIANA di FLEBOLOGIA; era il 14 marzo 1986! Avversata fin dall'inizio da boriose società angiologiche dell'epoca, ignoranti la flebologia, la S.I.F. trovò proprio in ciò lo stimolo culturale che produsse i primi grandi studi sull'emodinamica venosa. Ann. Ital. Chir., 2014 85: 308 Nel 1990 nasceva così la prima Rivista Scientifica ufficiale della S.I.F.: "FLEBOLOGIA". Grazie al grande aiuto di Roberto Bisacci redattore capo e anima della stessa, riuscimmo ad avere grande risonanza europea, anzi mediterranea, per lo spessore degli studi e dei conseguenti articoli scientifici in essa pubblicati, tanto che si rese necessaria l'edizione in italiano, francese, inglese … e in arabo! Nel 1996, con l'intento di pacificare i grandi appetiti politici di altre associazioni flebologiche nate successivamente alla S.I.F., la Società Italiana di Flebologia promosse e sostenne la nascita del Collegio Italiano di Flebologia che, appena nato, divorò la Rivista "FLEBOLOGIA" per fare spazio al suo organo ufficiale "Acta Phlebologica". Ebbe però anche il grande merito della stesura delle prime linee guida flebologiche che oggi tutto il mondo scientifico cita. Ma i troppi appetiti politici stimolati dalla crescita del Collegio ne decretarono la fine, con l'uscita della S.I.F. dalla confederazione. Nel 2000 la Federazione Nazionale delle Società Medico Scientifiche riconosceva ufficialmente come Associata la Società Italiana di Flebologia, unica società flebologica. Nel 2006 il grande evento: la S.I.F. otteneva la Certificazione di Qualità ISO 9001: 2000. Nel 2014, con l'attuale Presidenza Marco Apperti e l'entusiastica collaborazione del Consigliere Gennaro Quarto, è giunto a compimento il progetto di poter fare riferimento alla rivista internazionale Annali Italiani di Chirurgia quale Giornale Ufficiale della Società Italiana di Flebologia, in virtù di un accordo collaborativo raggiunto con

Genovese, Giuseppe

2014-01-01

12

Diverticolo di Meckel  

Microsoft Academic Search

\\u000a Il diverticolo di Meckel rappresenta una malformazione dell’intestino tenue presente, molto spesso in forma asintomatica,\\u000a nel 2–4% circa dalla popolazione. La sua esistenza è legata a un difetto di obliterazione del dotto onfalo-mesenterico ed\\u000a è per questo allocato sul margine antimesenterico dell’ileo a una distanza dalla valvola ileocecale che varia, in media, dai\\u000a 40 ai 100 cm. Nella maggior parte

L. Montinaro

13

REALIZZAZIONE DI UN AMBIENTE VIRTUALE PER LA VALUTAZIONE DELL'ERGONOMIA E DELL'USABILITÀ DI ORGANI DI COMANDO DI APPARECCHIATURE  

Microsoft Academic Search

SOMMARIO Nel presente lavoro gli autori propongono lo sviluppo e l'arrangiamento di un ambiente virtuale per la validazione funzionale, ergonomica e di usabilità di organi di comando di apparecchiature. In particolare viene descritta la progettazione e la successiva realizzazione di un simulatore meccanico a quattro gradi di libertà (4DOF) per il posizionamento, nell'ambiente fisico di prova, di un dispositivo haptic

DI GIRONIMO; Stefano PAPA

14

PREVISIONE DELLA ROTTURA DUTTILE NEI PROCESSI DI IDROFORMATURA DI TUBI E LAMIERE UTILIZZANDO UN MODELLO DI DANNO NON LINEARE  

Microsoft Academic Search

Sommario L'idroformatura di tubi e lamiere è un processo di stampaggio che permette di ottenere, in un elemento integrato, oggetti che con i metodi di fabbricazione tradizionali sono realizzati a partire da più parti saldate, con notevoli vantaggi in termini di peso, caratteristiche meccaniche e costi di fabbricazione. Il processo consiste nel formare il tubo o la lamiera utilizzando l'elevata

M. Rossi; A. Ruggiero

15

INDAGINE DI PATOLOGIE DOVUTE A VARIAZIONI DI PARAMETRI ELETTROLITICI MEDIANTE ANALISI E RICONOSCIMENTO DI SEGNALI BIOLOGICI ECG  

Microsoft Academic Search

Una cellula cardiaca presenta una differenza di potenziale di membrana tra l'interno elettronegativo e l'esterno positivo. Esiste un potenziale transmembrana che, tuttavia, nel corso del ciclo cardiaco subisce una modificazione, nel senso che alcuni sistemi di pompa degli ioni (sodio, potassio, calcio e cloro) consentono la migrazione degli stessi e, di conseguenza, causano un cambiamento nella polarizzazione di membrana. In

A. Calisto; B. Azzerboni; G. Consolo; G. Finocchio; V. Puliafito; A. Romeo

16

Sessione di riferimento: Reti  

Microsoft Academic Search

Prendere una decisione è un atto di responsabilità, per arrivarci occorre conoscere il contesto e le ipotetiche conseguenze della possibile azione. Conoscere implica mettere in relazione numerosi elementi e attori per giustificare e\\/o consensualizzare un'azione. In tale ambito si intende analizzare i percorsi istituzionali che generano conoscenza \\/ azione e i loro effetti significativi sull'ambiente e sulla società. L'intento è

Alessandro GRELLA

17

La sincronizzazione nelle reti numeriche di trasporto  

Microsoft Academic Search

A partire dalla seconda metà degli anni '80 si è sviluppata un'intensa attività di ricerca e standardizzazione riguardante i sistemi e le reti basate sulla gerarchia di multiplazione numerica sincrona SDH. Tale sviluppo è stato favorito dalla concreta necessità di dare risposta alle crescenti esigenze, manifestate sia dall'utenza sia dai gestori di reti e servizi, di maggiore capacità e flessibilità

M. Carbonelli; D. De Seta; D. Perucchini

1993-01-01

18

Strategie di crescita nel settore delle agenzie di viaggio: sostenibilità finanziaria  

Microsoft Academic Search

Strategie di crescita nel settore delle agenzie di viaggio: sostenibilità finanziaria (di Ruggero Sainaghi) - ABSTRACT: Il presente scritto si propone di analizzare i risvolti finanziari delle strategie di crescita nel settore delle agenzie di viaggio (d’ora in poi AdV), focalizzando l’attenzione soprattutto sui flussi di cassa generati dalla gestione tipica. Tale riflessione trae origine dalle dinamiche competitive in atto

Ruggero Sainaghi

2001-01-01

19

Di(hydroxyphenyl)- benzimidazole monomers  

NASA Technical Reports Server (NTRS)

Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

Connell, John W. (inventor); Hergenrother, Paul M. (inventor); Smith, Joseph G. (inventor)

1993-01-01

20

VULNERABILITÀ DELLA REGIONE SARDEGNA AGLI EVENTI ESTREMI DI PRECIPITAZIONE  

Microsoft Academic Search

Verranno presentati alcuni risultati di un'analisi degli eventi estremi di precipitazione in Sardegna, che considera anche la presenza di trend. L'uso congiunto di tali risultati e delle informazioni sulla vulnerabilità del territorio rispetto, ad esempio, alla presenza di aree protette, di aree urbane o al potenziale rischio idrogeologico, può permettere di definire indici in grado di stimare l'impatto di tali

21

Un programma di Screening Prenatale per la Trisomia 21: 14 anni di esperienza torinese  

Microsoft Academic Search

SUMMARY Si descrive l'organizzazione dello screening prenatale per la trisomia 21, considerando che non si tratta di un semplice test di laboratorio, ma di un programma articolato e multidisciplinare rivolto alla popolazione delle gestanti. Si presentano le prove dell'efficacia e della appropriatezza di un programma di screening prenatale per la sindrome di Down organizzato su scala semi-regionale, alla luce dei

Marco Perona; Franco Altare; Carla Bollati; Daniela Dall; Varvara Guaraldo; Enza Pavanello; S. C. Chimica

22

SEMGRID: APPLICAZIONE A SCALA TERRITORIALE DI MODELLI EPIDEMIOLOGICI E COLTURALI  

Microsoft Academic Search

SemGrid è un software con funzionalità GIS raster, sviluppato presso l'Università di Udine, che permette l'applicazione territoriale di modelli di simulazione. E' uno strumento di generale e facile impiego nel trattamento di informazioni territoriali finalizzate alla valutazione, classificazione e gestione del territorio, anche attraverso l'uso diretto di modelli di simulazione sviluppati con l'ambiente di modellazione SEMoLa (Simple Easy Modelling Language).

F. Danuso; M. Sandra

23

L'ATTEGGIAMENTO MAGGIORITARIO NEI CONFRONTI DELLE STRATEGIE DI ACCULTURAZIONE MINORITARIE: L'IMPORTANZA DI CONSIDERARE PIÙ LIVELLI DI ANALISI  

Microsoft Academic Search

La ricerca psicosociale ha ampiamente evidenziato come l'acculturazione sia un processo che coinvolge sia i membri dei gruppi maggioritari sia quelli appartenenti ai gruppi minoritari. In proposito, Bourhis, Moise, Perreault e Senecal (1997) hanno proposto il modello di acculturazione interattiva, secondo cui l'esito del processo di acculturazione dipende dalla corrispondenza tra gli orientamenti di acculturazione espressi dai gruppi che entrano

Dino Giovannini; Andrea Pintus; Loris Vezzali

24

CARATTERIZZAZIONE MECCANICA DI UN FILM PLASTICO BIODEGRADABILE E COMPOSTABILE  

Microsoft Academic Search

Sommario I principi di sostenibilità, ecoefficienza e chimica verde sono alla base di un nuovo modo di intendere le materie plastiche, che si traduce in una progettazione che interessa l'intero ciclo di vita del prodotto. Il lavoro presentato è stato incentrato sull'analisi di un nuovo materiale plastico, compostabile e biodegradabile al 100%, al fine di definirne le caratteristiche e verificarne

C. Casavola; A. Mastrandrea; C. Pappalettere

25

Facoltà di Architettura - Corso di laurea magistrale in ARCHITETTURA  

Microsoft Academic Search

Recuperare città e paesaggio è, in Italia, uno dei più delicati compiti al quale le giovani generazioni possono candidarsi; le trasformazioni urbane e territoriali ingenti alle quali il paesaggio è stato comunque sinora sottoposto - con variabile consapevolezza politica e disciplinare soprattutto nel secondo dopoguerra - discendendo da processi di governo intricati, spesso sovrapposti, talvolta eccezionali, devono essere ancora valutate

Corso Socrates; Caterina Bini; Gioia Martini; Maria Grazia Arca; Alessio Carbone; Maria Grazia Giardinelli; Piero Grezzi; Lucia Guarino; Dania Marzo; Maria Teresa Idone

26

Modelli e misure di performance aziendale: analisi della letteratura e spunti di ricerca  

Microsoft Academic Search

I sistemi di misurazione delle performance (SMP) nascono e si diffondono con l’obiettivo di orientare in maniera dinamica i comportamenti dei responsabili aziendali verso l’attuazione delle strategie. L’esigenza di utilizzo di questi strumenti si rafforza peraltro con la presa d’atto che gli strumenti di controllo tradizionale, a base esclusivamente contabile, impediscono una lettura efficace dei risultati e delle relative cause

Nicola Castellano

2011-01-01

27

Strategie di caccia degli ultimi epigravettiani. Lo studio funzionale delle armature litiche di Riparo Cogola, livello 19  

Microsoft Academic Search

RIASSUNTO - Strategie di caccia degli ultimi epigravettiani. Lo studio funzionale delle armature litiche di Riparo Cogola, livello 19 - Oggetto di questo articolo è lo studio funzionale realizzato sulle armature litiche di Riparo Cogola (livello 19), ubicato a 1070 m s.l.m., in località Pragrande, sull'Altopiano di Folgaria (Trento). Lo scopo del lavoro è comprendere la destinazione funzionale di questi

Sara ZIGGIOTTI; Giampaolo DALMERI

28

Modello di valutazione dell'attitudine fisica del territorio per la realizzazione di impianti cedui da biomassa in Italia  

Microsoft Academic Search

Le piantagioni governate a ceduo a turno breve (short rotation forestry - SRF) rappresentano il modello di arboricoltura da legno maggiormente idoneo alla produzione di biomassa lignocellulosica da destinare a usi energetici. La limitata disponibilità di risorse e la rete sempre più complessa di relazioni che coinvolgono l'uso del territorio pon- gono l'esigenza di una attenta programmazione territoriale di questo

Riccardo Salvati; Gherardo Chirici; Piermaria Corona

2007-01-01

29

ANALISI TERMO-MECCANICA CON TECNICHE COMBINATE STRUTTURALI E CFD DEL COMPORTAMENTO DI UN FANALE AUTOVEICOLISTICO IN CONDIZIONI DI PROVA E DI UTILIZZO  

Microsoft Academic Search

Sommario Il lavoro si occupa della definizione di una metodologia completa per l'analisi termo-meccanica di componenti ottici per autoveicoli, prendendo le mosse da un problema industriale di criticità nel superamento di test previsti da normativa su fanali di \\

F. Cimolin; A. Menotti; M. Rabito; R. Vadori

30

The "Bestie di Satana" murders.  

PubMed

In recent years, satanic groups have been responsible for various types and degrees of crimes. We report the case of a number of murders committed in Italy by a group of young people calling themselves the "Bestie di Satana". Forensic psychiatric assessment of the members of a satanic sect charged with the crime revealed that all the young people had a fragile, immature personality, a very low level of education and were socially disadvantaged. The trial of the members of the "Bestie di Satana" sect was concluded with the verdict of deliberate murder, and all the members were given long jail sentences. This report should lead us to explore social and cultural responses to juvenile satanism, statistically shown to be a relatively rare phenomenon but with a high criminal potential. PMID:24117906

Birkhoff, Jutta; Candelli, Chiara; Zeroli, Stefania; La Tegola, Donatella; Carabellese, Felice

2013-11-01

31

Il ruolo di Guglielmo Marconi  

Microsoft Academic Search

\\u000a Marconi, come risulta dai verbali, non era molto assiduo alle riunioni del Direttorio del CNR. In quel periodo, nonostante\\u000a il manifestarsi dei primi sintomi dellamalattia cardiaca che l’avrebbe condotto alla morte nel 1937, continuava a dividersi\\u000a fra numerosi impegni: la Reale Accademia d’Italia di cui era stato nominato da poco presidente, la costruzione della prima\\u000a stazione radio del Vaticano, gli

Franco Foresta Martin; Geppi Calcara

32

Influenza delle politiche pubbliche sulle strategie logistiche di impresa  

Microsoft Academic Search

Lo sviluppo delle attività di trasporto, distribuzione e logistica avuto in Europa nel corso degli ultimi venti anni risulta strettamente connesso con lo sviluppo economico ed industriale e, in un secondo momento, con i processi di globalizzazione. Si amplia quindi il campo di riferimento della logistica che esce dai singoli confini nazionali e necessita di nuovi modelli gestionali e di

Claudia Burlando; Manuela Basta

2004-01-01

33

Elementi Per UNA Piattaforma Di Categorizzazione Semantico-Ontologica  

Microsoft Academic Search

I. Introdttzione Da alcuni anni it termine 'ontologia' sembra aver ottenuto piena cittadinanza anche in diversi ambiti legati a ricerche di intelligenza artificiale, ed in particolare in teoria delle basi di dati e di analisi del linguaggio naturale. Si tratta di un movimento in fase di rapida evoluzione che sembra riuscire a richiamare un crescente interesse. In altra sede ([Poli

Roberto Poli

2000-01-01

34

MISURE DI EVAPOTRASPIRAZIONE IN AMBIENTE SUBURBANO CON MINI-LISIMETRI  

Microsoft Academic Search

I lisimetri sono nati originariamente per la conduzione di studi sul bilancio idrico delle colture legati sia alla calibrazione e validazione delle equazioni di stima dell'ET0 sia alla determinazione dei coefficienti colturali (kc) necessari per trasformare i valori di ET0 in valori di ETM. In termini generali un lisimetro è un blocco di terreno inserito in un apposito contenitore e

Tommaso Maggiore; Luigi Mariani; Simone Parisi; Gabriele Cola

35

Produzione industriale di generatori e kit  

Microsoft Academic Search

\\u000a A partire dal giugno 1991, con il recepimento in Italia della Direttiva europea 89\\/343\\/CEE [1], il campo di applicazione della normativa in materia di specialità medicinali è stato esteso anche ai radiofarmaci, ai generatori,\\u000a ai kit e ai precursori radioattivi (radionuclidi utilizzati per la preparazione di sostanze radiomarcate prima della somministrazione).\\u000a In precedenza tali prodotti erano sottoposti a normative diverse

R. Pasqualini; A. Bugatti; E. Raspanti

36

La valorizzazione delle produzioni agroalimentari regionali e locali tra strategie di apprendimento e strategie di marketing  

Microsoft Academic Search

La valorizzazione delle produzioni agroalimentari regionali e locali tra strategie di apprendimento e strategie di marketing (di Ivan Malevolti) - ABSTRACT: The deep relation between managerial training and local and regional spread capability to develop entrepreneurial strategies is just shown here. Training, thanks to different courses for different farmers and business people, is important to improve knowledge in farm and

Ivan Malevolti

2000-01-01

37

LA MUSEALIZZAZIONE DEI REPERTI ORGANICI DI GRANDI DIMENSIONI DA SCAVI ARCHEOLOGICI . PROGETTO DI RICERCA  

Microsoft Academic Search

li ultimi anni hanno visto un notevole incremento delle scoperte archeologiche di relitti di imbarcazioni antiche , non soltanto in contesti subacquei ma anche terrestri , in siti un tempo occupati dalle acque. In molti di questi rinvenimenti sono stati recu - perati numerosi manufatti , soprattutto lignei, che hanno stimolato la sensibilità degli addetti ai lavori verso lo sviluppo

R. Albicocco

38

IL PROGRAMMA DI AZIONE LOCALE DI LOTTA ALLA SICCITÀ E DESERTIFICAZIONE IN EMILIA-ROMAGNA  

Microsoft Academic Search

Il Programma di Azione Locale di lotta alla siccità e desertificazione (PAL) per la Regione Emilia-Romagna intende affrontare il problema del rapporto tra irrigazione e squilibrio del bilancio idrico di bacino, valutando la sostenibilità delle scelte colturali, anche alla luce degli attuali e dei prossimi scenari climatici. La struttura concettuale proposta per il PAL Emilia-Romagna si rifà al sistema degli

Lucio Botarelli; Vittorio Marletto; William Pratizzoli; Andrea Spisni

39

Considerazioni generali sull’impostazione bayesiana di problemi non parametrici  

Microsoft Academic Search

Si fanno alcune considerazioni di natura generale sui problemi statistici non parametrici e sulla loro risoluzione dal punto\\u000a di vista bayesiano. Dopo aver posto in evidenza l’importanza delle medie associative come strumenti di analisi statistica\\u000a dei suddetti problemi, ci si propone di determinare la distribuzione iniziale e finale di una generica media associativa nell’ipotesi\\u000a che le misure di probabilit assegnabili

Donato Michele Cifarelli; Eugenio Regazzini

1979-01-01

40

CELLE A COMBUSTIBILE MCFC IN GEOMETRIA CILINDRICA DI PICCOLA TAGLIA  

Microsoft Academic Search

SOMMARIO Le celle a combustibile a carbonati fusi (MCFC) sono caratterizzate da alte temperature di funzionamento (600-700°C) e consentono la produzione di energia elettrica con elevati rendimenti. Tuttavia, allo stato attuale, sono state realizzate celle MCFC di grossa taglia (da qualche centinaio di kW a decine di MW). Nel presente lavoro sono illustrati i risultati dello studio di una cella

Umberto Di Matteo; Federico Rossi; Andrea Nicolini

41

Ricerche sulla componente dura della radiazione penetrante eseguite per mezzo di nuclei di ferro magnetizzati  

Microsoft Academic Search

Riassunto  Si descrive un complesso di esperienze eseguite parte a Roma, parte a Pian Rosà (presso Cervinia di Val d’Aosta) con lo scopo\\u000a di ottenere indicazioni sullo spettro energetico della componente dura della radiazione cosmica, utilizzando un dispositivo\\u000a di nuclei di ferro magnetizzati. L’interpretazione dei risultati sperimentali suggerisce quanto segue:\\u000a \\u000a \\u000a 1?) \\u000a \\u000a Se si ammette che lo spettro delle energieE dei mesoni,

M. Conversi; E. Scrocco

1943-01-01

42

Principali componenti di uno scanner TC  

Microsoft Academic Search

\\u000a I requisiti strutturali di una sala in cui si svolge attività diagnostica mediante tomografia computerizzata variano in funzione\\u000a del tipo di apparecchiatura prevista e della tipologia di esami che saranno effettuati. In linea generale, una diagnostica\\u000a TC prevede tre aree distinte.\\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Sala diagnostica: è il locale nel quale sono posizionati lo scanner TC (gantry e lettino porta-paziente), il generatore,

Simona Corona; Silvia Cavaliere; Cristiana Baggiani

43

Problematiche di sviluppo dell'e-learning in Italia: i risultati di un'indagine empirica  

Microsoft Academic Search

Problematiche di sviluppo dell’e-learning in Italia: i risultati di un’indagine empirica (di Gian Luca Gregori, Valerio Temperini) - ABSTRACT: Nell’era della società e dell’economia della conoscenza, si osserva una particolare attenzione per le soluzioni offerte dalla nuove tecnologie soprattutto in tema della formazione continua. E’ in tale contesto che l’e-learning sta suscitando un crescente interesse, grazie ai diversi vantaggi e

Gian Luca Gregori; Valerio Temperini

2007-01-01

44

Screening prenatale, ecografico e biochimico di cromosomopatie  

Microsoft Academic Search

L’interesse dei ricercatori nell’identificare marcatori di cromosomopatie nasce dalla considerazione che nelle gravide over\\u000a 35, mediante tecniche invasive, sono diagnosticate solo il 40% circa delle alterazioni cromosomiche mentre il 60% delle cromosomopatie\\u000a si rileva in nati da gestanti di età inferiore a 35 anni (molto più numerose delle gravide over 35) e senza indicazioni specifiche\\u000a alla diagnostica invasiva.

Antonio L. Borrelli; Maria Felicetti; Anna Domenico

45

PENGAJARAN DAN PEMBELAJARAN BAHASA MELAYU DI INSTITUSI PENDIDIKAN TINGGI SWASTA DI NEGERI SARAWAK  

Microsoft Academic Search

Abstrak: Kajian ini bertujuan untuk mendapatkan persepsi pelajar Institusi Pendidikan Tinggi Swasta (IPTS) yang belajar di negeri Sarawak tentang pengajaran dan pembelajaran Bahasa Melayu dalam kalangan tenaga pengajar di IPTS yang dikaji. Secara khusus, kajian ini bertujuan untuk meninjau persepsi pelajar Bumiputera dan bukan Bumiputera terhadap pendekatan pengajaran, perkaedahan pengajaran, sukatan pelajaran, bahan pengajaran dan penilaian pengajaran dalam pembelajaran Bahasa

Zamri Mahamod; Nik Mohd; Rahimi Nik Yusoff

46

Exclusive e+e-, di-photon and di-jet production at the Tevatron  

SciTech Connect

Results from studies on exclusive production of electron-position pair, di-photon, and dijet production at CDF in proton-antiproton collisions at the Fermilab Tevatron are presented. THe first observation and cross section measurements of exclusive e{sup +}e{sup -} and di-jet production in hadron-hadron collisions are emphasized.

Terashi, Koji; /Rockefeller U.

2007-05-01

47

Determinazione di soglie pluviometriche per l'innesco di frane in Emilia - Romagna  

Microsoft Academic Search

1. PREMESSA Come è noto, i movimenti franosi si attivano o riattivano pre- valentemente in seguito a precipitazioni più o meno intense e prolungate. Gli studi e le analisi degli eventi verificatisi in passato testimoniano che la maggior parte delle attivazioni di frane sono raggruppate in intervalli di tempo brevi e defi- niti e strettamente correlati a eventi meteorologici, costi-

Marco Pizziolo; Lorenzo Del Maschio; Giampiero Gozza; Sara Pignone

48

Differential binding of 2'-biotinylated analogs of c-di-GMP with c-di-GMP riboswitches and binding proteins.  

PubMed

C-di-GMP has emerged as a signalling molecule that regulates a variety of processes in several bacteria; therefore there is interest in the development of biotinylated analogs for the identification of binding partners. No detailed study has been done to evaluate if biotinylated analogs of c-di-GMP are capable of binding to c-di-GMP receptors. Herein, we evaluate the binding of commercially available 2'-biotinylated c-di-GMP and phosphorothioate 2'-biotinylated c-di-GMP, prepared via a facile solid-phase synthesis, to several c-di-GMP receptors. Docking, using Autodock vina software, as well as experimental studies of these analogs, with c-di-GMP class I and II riboswitches and binding proteins, reveal that some, but not all, c-di-GMP receptors can tolerate the 2'-modification of c-di-GMP with biotin. PMID:22182995

Luo, Yiling; Zhou, Jie; Watt, Sarah K; Lee, Vincent T; Dayie, T Kwaku; Sintim, Herman O

2012-03-01

49

[Di George syndrome, exemplary rhomboencephalic neurocristopathy].  

PubMed

Di George's syndrome associates hypocalcemia and hyperphosphoremia (phosphocalcic disorders from absence of the parathyroids), cell immunity disorders related to agenesis or hypoplasia of the thymus, and large vessels malformations (pulmonary artery, aorta) with cardiac lesions. The disorder is the result of deletion of rhomboencephalic neural crests cells, Di George's syndrome being an exemplary rhomboencephalic neurocristopathy. This organic syndrome is associated with early disorders of the same neurological region (the rhomboencephalon), expressed clinically by sucking and swallowing disturbances and cardiorespiratory regulatory disorders. Early rhomboencephalic lesions can lead to velopalatal division and microretrognathism secondary to a lingual motility disturbance. The association of this neurocristopathy with a neural tube lesion constitutes a dysneurulation. Fetal and neonatal retrognathism are evidence of bulbar involvement. Di George's and Pierre Robin's syndromes constitute two fairly similar clinical expressions of the same embryonic deficiency of rhomboencephalic neurulation. PMID:6574567

Couly, G; Lagrue, A; Griscelli, C

1983-01-01

50

21 CFR 178.3940 - Tetraethylene glycol di-(2-ethylhexoate).  

Code of Federal Regulations, 2010 CFR

...Aids § 178.3940 Tetraethylene glycol di-(2-ethylhexoate). Tetraethylene glycol di-(2-ethylhexoate) containing not more than 22 parts per million ethylene and/or diethylene glycols may be used at a level not to...

2010-01-01

51

21 CFR 178.3940 - Tetraethylene glycol di-(2-ethylhexoate).  

Code of Federal Regulations, 2013 CFR

...Aids § 178.3940 Tetraethylene glycol di-(2-ethylhexoate). Tetraethylene glycol di-(2-ethylhexoate) containing not more than 22 parts per million ethylene and/or diethylene glycols may be used at a level not to...

2013-04-01

52

21 CFR 178.3940 - Tetraethylene glycol di-(2-ethylhexoate).  

Code of Federal Regulations, 2010 CFR

...Aids § 178.3940 Tetraethylene glycol di-(2-ethylhexoate). Tetraethylene glycol di-(2-ethylhexoate) containing not more than 22 parts per million ethylene and/or diethylene glycols may be used at a level not to...

2009-04-01

53

Ecografia con mezzo di contrasto nelle patologie gastroenteriche  

Microsoft Academic Search

I mezzi di contrasto per ecografia, come già ampiamente argomentato, sono costituiti da microbolle delle dimensioni di 3–5\\u000a µm che, iniettate in bolo, aumentano il segnale ultrasonografico proveniente dal letto vascolare o capillare, e forniscono\\u000a un’adeguata rappresentazione del flusso ematico del microcircolo di un tessuto o di un organo (ecoangiografia perfusionale).\\u000a Poiché questi composti non si distribuiscono nei liquidi tissutali

Giovanni Maconi; Cristina Bezzio; Gabriele Bianchi Porro

54

Transcriptional Changes in Hepatic Tumors of Rats Induced by Di(2-ethylhexyl) phthalate and Di-n-Octyl phthalate.  

National Technical Information Service (NTIS)

Di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DOP) are nongenotoxic carcinogens found in drinking water, which induce mainly liver tumors. The mechanism of tumorigenesis by these chemicals remains to be elucidated. The present study was unde...

J. C. Kandala A. B. DeAngelo T. V. Reddy F. B. Daniel R. V. Guntaka

1993-01-01

55

LA REGIONALIZZAZIONE DEI MERCATI COME FATTORE DI INTEGRAZIONE GEOPOLITICA  

Microsoft Academic Search

Negli ultimi anni, i processi di frammentazione (balkanizzazione) dello spazio globale e di mondializzazione dei mercati nazionali o regionali hanno concorso, sinergicamente, a sostenere l'egemonia del maggiore attore globale, gli Stati Uniti d'America, e, conseguentemente, dei gruppi di pressione che ne esprimono la dirigenza. Tuttavia, l'attuale crisi economico-finanziaria del sistema \\

Tiberio Graziani

56

Petrogenesis of garnet lherzolite, Cima di Gagnone, Lepontine Alps  

Microsoft Academic Search

Garnet lherzolite at Cima di Gagnone has chemical and mineralogical properties similar to those of other garnet lherzolites in the lower Pennine Adula\\/Cima Lunga Nappe (Alpe Arami, Monte Duria). The Cima di Gagnone occurrence encloses mafic boudins that belong to an eclogite-metarodingite suite common in the numerous neighboring ultramafic lenses. The ultramafic rocks at Cima di Gagnone, including the garnet

Bernard W. Evans; Volkmar Trommsdorff

1978-01-01

57

ANALISI TEORICA DEL CAMPO DI SPOSTAMENTO PRODOTTO DA UN TERREMOTO SUL PROPRIO PIANO DI FAGLIA: EFFETTI SULLA GEOMETRIA E L'ORIENTAZIONE DELLA FAGLIA  

Microsoft Academic Search

L'approccio comunemente utilizzato per il calcolo teorico del campo di deformazione indotto da una sorgente sismica in un mezzo elastico è basato sull'equivalenza fra una dislocazione di taglio elementare e una doppia coppia di forze puntiformi. Il campo prodotto da una sorgente di dimensioni finite viene poi ottenuto tramite sovrapposizione lineare dei campi generati da una distribuzione di doppie coppie

S. Tinti; A. Armigliato; A. Manucci

58

Amylase activity of Torulopsis ingeniosa Di Menna.  

PubMed

Torulopsis ingeniosa DI MENNA was found to possess an alpha-amylase strongly attached to the cell wall, its pH optimum being at 5.5, optimum temperature at 50 degrees C, highly sensitive to thermal inactivation. The enzyme was found to be induced by starch but the synthesis is not subject to a glucose effect. PMID:33881

Moulin, G; Galzy, P

1978-01-01

59

Osteoporosi: la scienza di base, inquadramento, classificazione  

Microsoft Academic Search

L’osso è un tessuto connettivo specializzato, costituito da una matrice extracellulare mineralizzata e da una componente cellulare.\\u000a La matrice extracellulare del tessuto osseo è formata per il 40% da componenti organiche e per il 60% da componenti inorganiche.\\u000a La componente organica è rappresentata da collagene, proteoglicani, proteine non collageniche, fattori di crescita e citochine.

U. Tarantino; I. Cerocchi; A. Andreoli

60

CYCLIC DI-NUCLEOTIDE SIGNALLING ENTERS THE EUKARYOTE DOMAIN  

PubMed Central

SUMMARY Cyclic di-GMP (c-di-GMP) is the prevalent intracellular signalling intermediate in bacteria. It triggers a spectrum of responses that cause bacteria to shift from a swarming motile phase to sessile biofilm formation. However, additional functions for c-di-GMP and roles for related molecules, such as c-di-AMP and c-AMP-GMP continue to be uncovered. The first usage of cyclic-di-nucleotide (c-di-NMP) signalling in the eukaryote domain emerged only recently. In Dictyostelid social amoebas, c-di-GMP is a secreted signal that induces motile amoebas to differentiate into sessile stalk cells. In humans, c-di-NMPs, which are either produced endogenously in response to foreign DNA or by invading bacterial pathogens, trigger the innate immune system by activating the expression of interferon genes. STING, the human c-di-NMP receptor, is conserved throughout metazoa and their closest unicellular relatives, suggesting protist origins for human c-di-NMP signalling. Compared to the limited number of conserved protein domains that detect the second messengers cAMP and cGMP, the domains that detect the c-di-NMPs are surprisingly varied.

Schaap, Pauline

2014-01-01

61

L'esperienza piemontese su oltre 200.000 gravidanze sottoposte a test di screening prenatale per la sindrome di Down dal 1990 al 2008: risultati con Tritest, Test integrato, Test combinato  

Microsoft Academic Search

Differenti marcatori e differenti associazioni di marcatori sono stati proposti dalla fine degli anni '80 per fornire un efficiente screening prenatale alle donne di tutte le età allo scopo di ottenere una stima più accurata del rischio individuale di sindrome di Down. In Piemonte i test di screening sono stati offerti dal 1990 con crescenti livelli di adesione. Le caratteristiche

Daniela C. Dall; Carla Bollati; Elisabetta Muccinelli; Franco Altare; Enza Pavanello; Varvara Guaraldo; Guglielmo Bracco; Annarita Filippo; Daniela Fortina; Elsa Viora; Simona Bastonero; Giuseppe Errante; Andrea Sciarrone; Marco Pagliano; Elena Gullino; Maria Grazia Alemanno; Simona Sdei; Roberto Scali; Pietro Gaglioti; Tullia Todros

62

Brand extension nelle imprese di servizi sportivi: opportunità ed implicazioni manageriali nel caso del calcio  

Microsoft Academic Search

L’obiettivo del lavoro è di definire le opportunità e le implicazioni manageriali connaturate all’implementazione di strategie di sfruttamento dei brand all’interno delle imprese di servizi sportivi. L’interesse nei confronti delle strategie di brand discende da un lato dalla necessità per le imprese sportive di diversificare le proprie attività e di svincolare le performance economiche dai risultati sul campo e, dall’altro,

Tommasina Pianese

2010-01-01

63

Il pino d'Aleppo nell'arboricoltura da legno in ambiente mediterraneo. Un caso di studio: l'Azienda Mazzone (Cosenza)  

Microsoft Academic Search

La realizzazione di impianti con specie forestali rappresenta un significativo momento di recupero di terreni agricoli marginali e consente di produrre biomassa e, al contempo, di migliorare i suoli e creare soluzioni di continuità nel paesaggio agrario. La coltivazione di specie forestali per la produzione di legno configura un sistema bio-ecologico di tipo agrono- mico, caratterizzato da algoritmi colturali intensivi

Francesca Gentile; Vittoria Mendicino; Giuliano Menguzzato; Luca Pelle

2007-01-01

64

Di-interstitial defect in silicon revisited  

SciTech Connect

Infrared spectroscopy was used to study the defect spectrum of Cz-Si samples following fast neutron irradiation. We mainly focus on the band at 533 cm{sup ?1}, which disappears from the spectra at ?170 °C, exhibiting similar thermal stability with the Si-P6 electron paramagnetic resonance (EPR) spectrum previously correlated with the di-interstitial defect. The suggested structural model of this defect comprises of two self-interstitial atoms located symmetrically around a lattice site Si atom. The band anneals out following a first-order kinetics with an activation energy of 0.88 ± 0.3 eV. This value does not deviate considerably from previously quoted experimental and theoretical values for the di-interstitial defect. The present results indicate that the 533 cm{sup ?1} IR band originates from the same structure as that of the Si-P6 EPR spectrum.

Londos, C. A.; Antonaras, G. [Solid State Section, Physics Department, University of Athens, Panepistimiopolis, Zografos, 157 84 Athens (Greece)] [Solid State Section, Physics Department, University of Athens, Panepistimiopolis, Zografos, 157 84 Athens (Greece); Chroneos, A. [Engineering and Innovation, The Open University, Milton Keynes MK7 6AA (United Kingdom) [Engineering and Innovation, The Open University, Milton Keynes MK7 6AA (United Kingdom); Department of Materials, Imperial College London, London SW7 2BP (United Kingdom)

2013-11-21

65

Biomaterial based sulphur di oxide gas sensor  

NASA Astrophysics Data System (ADS)

Biomaterials are getting importance in the present research field of sensors. In this present paper performance of biomaterial based gas sensor made of gum Arabica and garlic extract had been studied. Extract of garlic clove with multiple medicinal and chemical utility can be proved to be useful in sensing Sulphur di Oxide gas. On exposure to Sulphur di Oxide gas the material under observation suffers some temporary structural change, which can be observed in form of amplified potentiometric change through simple electronic circuitry. Exploiting this very property a potentiometric gas sensor of faster response and recovery time can be designed. In this work sensing property of the said material has been studied through DC conductance, FTIR spectrum etc.

Ghosh, P. K.; Sarkar, A.

2013-06-01

66

Photochemistry of Matrix-Isolated Di-tert-butyldiazidosilane. Observation of Di-tert-butylsilylene and N,N'-Di-tert-butylsilanediimine,  

National Technical Information Service (NTIS)

The major product from 254-nm irradiation of matrix-isolated di-tert-butyldiazidosilane (3) is di-tert-butylsilylene (4), a highly reactive ground-state singlet species with lambda max 480 nm, which undergoes a subsequent photochemical C-H insertion to gi...

K. M. Welsh J. Michl R. West

1988-01-01

67

Cyclic di-AMP impairs potassium uptake mediated by a cyclic di-AMP binding protein in Streptococcus pneumoniae.  

PubMed

Cyclic di-AMP (c-di-AMP) has been shown to play important roles as a second messenger in bacterial physiology and infections. However, understanding of how the signal is transduced is still limited. Previously, we have characterized a diadenylate cyclase and two c-di-AMP phosphodiesterases in Streptococcus pneumoniae, a Gram-positive pathogen. In this study, we identified a c-di-AMP binding protein (CabP) in S. pneumoniae using c-di-AMP affinity chromatography. We demonstrated that CabP specifically bound c-di-AMP and that this interaction could not be interrupted by competition with other nucleotides, including ATP, cAMP, AMP, phosphoadenylyl adenosine (pApA), and cyclic di-GMP (c-di-GMP). By using a bacterial two-hybrid system and genetic mutagenesis, we showed that CabP directly interacted with a potassium transporter (SPD_0076) and that both proteins were required for pneumococcal growth in media with low concentrations of potassium. Interestingly, the interaction between CabP and SPD_0076 and the efficiency of potassium uptake were impaired by elevated c-di-AMP in pneumococci. These results establish a direct c-di-AMP-mediated signaling pathway that regulates pneumococcal potassium uptake. PMID:24272783

Bai, Yinlan; Yang, Jun; Zarrella, Tiffany M; Zhang, Yang; Metzger, Dennis W; Bai, Guangchun

2014-02-01

68

4-(Di-methyl-amino)-pyridinium trichlorido[4-(di-methyl-amino)-pyridine-?N]cobaltate(II)  

PubMed Central

In the anion of the title compound, (C7H11N2)[CoCl3(C7H10N2)], the CoII ion is coordinated by one N atom from a 4-(di­methyl­amino)­pyridine (DMAP) ligand and three Cl atoms, forming a CoNCl3 polyhedron with a distorted tetra­hedral geometry. In the crystal, cations and anions are linked via weak N—H?Cl and C—H?Cl hydrogen bonds. Double layers of complex anions stack along the b- axis direction, which alternate with double layers of 4-(di­methyl­amino)-pyridinium cations.

Guenifa, Fatiha; Hadjadj, Nasreddine; Zeghouan, Ouahida; Bendjeddou, Lamia; Merazig, Hocine

2013-01-01

69

Fair trade, premio di prezzo e fallimenti del mercato  

Microsoft Academic Search

Il premio di prezzo è solo una componente, non marginale, sicuramente la più caratteristica e facilmente comunicabile, ma certamente non decisiva nel modello Fair Trade. L’avere incentrato l’attenzione su questo specifico aspetto del meccanismo complessivo ha nascosto altri aspetti più rilevanti dello schema operativo. Nel presente lavoro si cerca di mostrare come l’impatto maggiore delle strategie di Fair Trade riguarda

A. Arrighetti

2007-01-01

70

Di-isophorone and related compounds. Part 10 13 C-nuclear magnetic resonance spectra of di-isophorone derivatives  

Microsoft Academic Search

13C-Nuclear magnetic resonance spectra of a series of di-isophorone derivatives have been mapped and the individual resonances assigned. Assignments were obtained by comparing and correlating the spectra of closely related di-isophorones of known structure. Estimates, based on approximate calculations, of the chemical shifts of the six methylene moieties of the di-isophorone skeleton are in fair agreement with the observed values.

Paul R. Davies; Alan R. Morgan; Frederick Kurzer

1983-01-01

71

ANALISI DI LAND SUITABILITY PER LA VALUTAZIONE DELL'IMPATTO DELLE VARIAZIONI CLIMATICHE SULLA COLTIVAZIONE DEL FRUMENTO NELLA PROVINCIA DI SETTAT, MAROCCO  

Microsoft Academic Search

Negli studi di Land Evaluation, la metodologia della Land Suitability consente di valutare la vocazionalità per la coltivazione di una data coltura in particolari condizioni pedo-climatiche. Tenendo conto dei dati disponibili e attraverso opportune modifiche della metodologia FAO, è stata valutata la vocazionalità della provincia di Settat (Marocco nord-occidentale) per il frumento nelle attuali condizioni climatiche e nelle condizioni climatiche

Valentina Mereu; Ileana Iocola; Donatella Spano; Andrea Motroni; Riad Balaghi; Pierpaolo Duce

72

Spin excitations in di-nuclear systems  

SciTech Connect

The spin excitations of products from two-body reactions have two sources: transfer of orbital motion into intrinsic spins via tangential friction and thermal excitations of di-nuclear spin modes. The relative importance of these two mechanisms is discussed for deep inelastic scattering, quasi-fission and spontaneous fission processes. The results of simple model calculations are compared to measured {gamma}-multiplicities in {sup 238}U induced quasi-fission reactions and it is concluded that the spin-excitation are only partially equilibrated during the interaction. 11 refs., 5 figs.

Back, B.B.

1990-01-01

73

Come diventare grandi rimanendo piccoli. Strategie di networking della Cooperazione Sociale ravennate  

Microsoft Academic Search

In numerosi paesi dell'Unione Europea, in questi ultimi anni, si assiste ad un processo di ridisegno (riforma) dei sistemi di welfare improntato da linee politiche che incentivano il passaggio da sistemi di finanziamento orientati al sostegno dell'offerta (gare di appalto, convenzionamento, ecc.) a sistemi volti al sostegno della domanda (buoni servizio, vouchers, accreditamento). All'interno di questi sistemi integrati di erogazione

Andrea Bassi

2008-01-01

74

Costruzione automatica di courseware in DyLOG  

Microsoft Academic Search

Nelle piattaforme di e-learning i corsi non possono seguire una struttura classica. I nuovi strumenti messi a disposizione dalla rete (chat, forum ipermedialita) impongono una rivisitazione della struttura dei contenuti e delle strategie didattiche utilizzate. In questo articolo si vuole descrivere un idea per aiutare i docenti nella definizione di un corso, inteso come materiale educativo e strategia didattica, avvalendosi

Laura Torasso

75

Supply Chain Management e competitività portuale: nuove prospettive di analisi  

Microsoft Academic Search

Supply Chain Management e competitività portuale: nuove prospettive di analisi (di Marcella De Martino, Alfonso Morvillo) - ABSTRACT: Nel dibattito recente sulla competitività portuale, grande rilevanza è stata data in letteratura all’approccio del Supply Chain Management quale nuovo paradigma per inquadrare strategie e posizionamento strategico dei porti. Il SCM sostiene lo sviluppo delle partnership tra gli attori della supply chain

Marcella De Martino; Alfonso Morvillo

2007-01-01

76

La gestione del rischio nelle apparecchiature di raffineria  

Microsoft Academic Search

Nella presente memoria viene illustrata la politica adottata dalla Raffineria di Milazzo per la valutazione dei rischi connessi all'esercizio delle apparecchiature. Vengono trattate le procedure attuate sia nei confronti delle attrezzature a pressione, con particolare attenzione alla metodica denominata Risk Based Inspection, che consente di indirizzare le ispezioni verso quegli items a cui è associato un maggior rischio, sia nei

Vincenzo Gazzotti; Giuseppe Chiofalo; Francesco Giacobbe; Salvatore Benedetto

77

Biological Effects Summary Report di(2-Ethylhexyl) Sebacate.  

National Technical Information Service (NTIS)

An evaluation of the health effects of di(2-ethylhexyl) sebacate (DEHS) was made to assess its potential use as substitute for di(2-ethylhexyl) phthalate (DEHP), which is used as a test aerosol in quantitative fit testing of respirators. A review of publi...

B. D. Silverstein O. White J. E. Brower N. M. Bernholc

1983-01-01

78

Caratterizzazione di una camera a estrapolazione come campione di misura per radiazione beta e realizzazione di un complesso di irraggiamento per la taratura di dosimetri. (Characterization of extrapolation chamber as measurement scale for beta radiations and implementation of irradiation equipment for dosimeter calibration).  

National Technical Information Service (NTIS)

A computerized system for beta dosimetry has been developed at the Divisione di Metrologia e Protezione delle Radiazioni Ionizzanti dell'ENEA Italian Agency for (New Technologies, Energy and Environment)di Bologna. The system allows an absolute measuremen...

E. Fantuzzi F. Monteventi

1993-01-01

79

Analisi numerica e sperimentale di nodi strutturali incollati per applicazioni automobilistiche  

Microsoft Academic Search

Sommario Il presente articolo contiene i risultati di una attività di studio dedicata ai nodo strutturali di un telaio automobilistico a traliccio, realizzato con elementi in materiale composito (tubi pultrusi), connessi ai nodi mediante incollaggio. Lo studio è stato condotto in collaborazione con la Picchio S.p.A. di Ancarano (Te), la quale sviluppa e produce autovetture da competizione e piccole serie

Enrico D'Amato; Marco Mancinelli; Giuseppe Carfagna

80

SAFE: un metodo per comprendere, ridurre ed accettare i rischi di progetto  

Microsoft Academic Search

Il presente lavoro descrive gli elementi fondamentali di un metodo di gestione del rischio di progetto che integra diversi approcci di pubblico dominio come il PRM body of knowledge del Project Management Institute, il CTC del Software Engineering Institute, il modello delle strategie Euromethod nonché quelli descritti da McFarlan, Archibald ed altri ancora. Benché originato nel campo delle Tecnologie dell'Informazione

Roberto Meli

2000-01-01

81

VALUTAZIONE DELLE PROPRIETA' MECCANICHE NEI MATERIALI IN ESERCIZIO CON PROVE DI LABORATORIO: LA FATICA TERMOMECCANICA  

Microsoft Academic Search

Le turbine a gas lavorano in condizioni operative estreme di temperatura e pressione per ottenere le massime presta- zioni dell'impianto energetico. Tali requisiti possono risultare al limite delle condizioni di progettazione delle pale, dei cuscinetti e dei numerosi componenti presenti nella camera di combustione. Di conseguenza la loro vita in esercizio può risultare limitata, come verosimilmente risulta dalla frequenza delle

M. Marchionni; S. Budano

2008-01-01

82

Percolazione di nutrienti e di fitofarmaci, consumo della risorsa idrica: l'agro- meteorologia può esprimere in modo compiuto la relazione suolo-pianta-atmosfera. Con il bilancio idrico e altri strumenti, soprattutto di carattere modellistico; è in grado di dare un supporto fondamentale alla tutela dell'ambiente e del territorio  

Microsoft Academic Search

sari al calcolo della domanda irrigua a diversa scala territoriale, dall'a- zienda alla regione, e permettono di valutare l'impatto ambientale delle tecniche agronomiche, deter- minando il rischio di contamina- zione delle acque di falda. La stima della percolazione pro- fonda e del ruscellamento superfi- ciale consente di calcolare il bilan- cio sia degli elementi nutritivi, quali azoto e fosforo, sia

L. Botarelli; Servizio IdroMeteo; Arpa Emilia-Romagna

2005-01-01

83

Thiophosphate Analogs of c-di-GMP: Impact on Polymorphism  

PubMed Central

Seven phosphorothioate analogs of c-di-GMP (all diastereomers of mono-, di-, and trithiophosphates) were prepared to assess the impact of the thioate substitutions on c-di-GMP polymorphism using 1D 1H and 31P NMR, along with 2D NOESY and DOSY, for both the Na+ and K+ salts. The K+ salts display more extensive higher order complex formation than the Na+ salts, resulting primarily in octamolecular complexes with K+, but tetramolecular complexes with Na+. Further, the presence of one or two [SP] sulfurs specifically stabilizes anti complexes and/or destabilizes syn complexes, while the presence of two [SP] sulfurs promotes extensive aggregation.

Zhao, Jianwei; Veliath, Elizabeth; Kim, Seho; Gaffney, Barbara L.

2009-01-01

84

4,6-Di-bromo-N-{3-[(4,6-di-bromo-2,3-di-methyl-phenyl)imino]butan-2-yl-idene}-2,3-di-methyl-aniline  

PubMed Central

The title compound, C20H20Br4N2, is a product of the condensation reaction of 4,6-di­bromo-2,3-di­methyl­aniline and butane-2,3-dione. The mol­ecule has a center of symmetry at the mid-point of the central C—C bond. The dihedral angle between the benzene ring and the 1,4-di­aza­butadiene plane is 78.3?(2)°. Niether hydrogen bonding nor aromatic stacking is observed in the crystal structure.

Huang, Lina; Du, Zhengyin; Liu, Wei; Che, Fushou

2013-01-01

85

Modelling Service Requirements Variability: The DiVA Way  

NASA Astrophysics Data System (ADS)

This chapter tackles the challenges of variability identification, modelling and implementation for service-based systems. The DiVA methodology is applied to the Mobile Phone Service Portability case-study to demonstrate its solutions to these challenges. The DiVA methodology utilises concepts of Aspect-Oriented Software Development to encapsulate service variants in distinct modules and uses Model-Driven Development techniques to analyse and transform conceptual designs into executable services. The DiVA approach provides a tool-supported methodology for managing dynamic variability in adaptive systems and taming system complexity.

Greenwood, Phil; Chitchyan, Ruzanna; Ayed, Dhouha; Girard-Reydet, Vincent; Fleurey, Franck; Dehlen, Vegard; Solberg, Arnor

86

Exposure and Risk Assessment for Phthalate Esters (Di(2-Ethylhexyl) Phthalate, Di-n-Butyl Phthalate, Dimethyl Phthalate, Diethyl Phthalate, Di-n-Octyl Phthalate, Butyl Benzyl Phthalate) (Revised).  

National Technical Information Service (NTIS)

This report assesses the risk of exposure to di(2-ethylhexyl) phthalate, di-n-butyl phthalate, dimethyl phthalate, diethyl phthalate, di-n-octyl phthalate, and butyl benzyl phthalate. This study is part of a program to identify the sources of and evaluate...

J. Perwak M. Goyer G. Schimke A. Eschenroeder J. Fiksel

1981-01-01

87

Vibrational frequencies and structural determinations of di-vinyl sulfone  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the structure and infrared spectra of di-vinyl sulfone. The vibrational frequencies of the di-vinyl sulfone molecule were analyzed using standard quantum chemical techniques. Frequencies were calculated at the MP2 and DFT levels of theory using the standard 6-311G* basis set. The structural transformation of the chemical agent bis(2-chloroehtyl) sulfide (HD, mustard gas) and the related symmetry to a previously study compounds [Spectrochim. Acta Part A 55 (1999) 121; Spectrochim. Acta Part A 57 (2001) 2417] makes the symmetry of the di-vinyl sulfone molecule an interesting candidate for study. The molecule exists normally in a C2 configuration. High-energy forms of di-vinyl sulfone with CS and C1 symmetries also exist.

Ellzy, Michael W.; Jensen, James O.; Kay, Jack G.

2003-03-01

88

Cyclic di-AMP: another second messenger enters the fray.  

PubMed

Nucleotide signalling molecules contribute to the regulation of cellular pathways in all forms of life. In recent years, the discovery of new signalling molecules in bacteria and archaea, as well as the elucidation of the pathways they regulate, has brought insights into signalling mechanisms not only in bacterial and archaeal cells but also in eukaryotic host cells. Here, we provide an overview of the synthesis and regulation of cyclic di-AMP (c-di-AMP), one of the latest cyclic nucleotide second messengers to be discovered in bacteria. We also discuss the currently known receptor proteins and pathways that are directly or indirectly controlled by c-di-AMP, the domain structure of the enzymes involved in its production and degradation, and the recognition of c-di-AMP by the eukaryotic host. PMID:23812326

Corrigan, Rebecca M; Gründling, Angelika

2013-08-01

89

Gli effetti delle agevolazioni finanziarie sulle decisioni di investimento e sulle performance delle imprese: una valutazione empirica della legge 488\\/92  

Microsoft Academic Search

La tematica delle agevolazioni finanziarie a favore delle imprese costituisce, da sempre, oggetto di notevole attenzione ed interesse da parte di studiosi, economisti e policy maker. La domanda di ricerca deriva da esigenze di policy - allo scopo di migliorare l’efficienza e l’efficacia delle norme di incentivazione - oltre che dalla richiesta di analisi empiriche per dare risposta a quesiti

Emilio Cardosi

2010-01-01

90

PCB Rogowski coils for high di\\/dt current measurement  

Microsoft Academic Search

In order to measure di\\/dt in the range of 10 to 20 kA\\/?s, air cored coils can be used. The coil's natural frequency limits the bandwidth of this probe. PCB coils have a natural frequency of 10 MHz or more. Theoretical analysis and measurements with di\\/dt of 5 kA\\/?s and 500 A are presented, employing the PCB coil in a

Nicolas Karrer; Patrick Hofer-Noser

2000-01-01

91

LA RIQUALIFICAZIONE DI COMPLESSI ARCHITETTONICI AD ALTA VALENZA STORICO-ARTISTICA DI PROPRIETÀ' DELLE AZIENDE USL: INDIVIDUAZIONE DI STRATEGIE METODOLOGICHE PER NUOVE IPOTESI DI IMPIEGO ALL'INTERNO DEL QUADRO NORMATIVO NAZIONALE  

Microsoft Academic Search

La presente memoria affronta il problema dell'applicazione ad una Azienda Sanitaria del Decreto Ministeriale del 6 febbraio 2004, emanato dalla Direzione Generale per i Beni Architettonici ed il Paesaggio di concerto con l'Agenzia del Demanio, che obbliga le pubbliche Amministrazioni a sottoporre alla verifica dell'interesse culturale i propri beni immobili. Il riconoscimento di interesse storico-artistico, secondo l'Art.12 del D. Lgs

L. Alberani; G. Cervato; M. Speciale; S. Mazzacane

92

DiZer: An Automatic Discourse Analyzer for Brazilian Portuguese  

Microsoft Academic Search

This paper presents DiZer, an automatic DIscourse analyZER for Brazilian Portuguese. Given a source text, the system automatically produces its corresponding rhetorical analysis, following Rhetorical Structure Theory - RST (Mann and Thompson, 1987). A rhetorical repository, which is DiZer main component, makes the automatic analysis possible. This repository, produced by means of a corpus analysis, includes discourse analysis patterns that

Thiago Alexandre Salgueiro Pardo; Maria Das Graças Volpe Nunes; Lucia Helena Machado Rino

2004-01-01

93

Dermatite atopica: dalla storia alle cure di oggi  

Microsoft Academic Search

La dermatite atopica (DA) è una malattia infiammatoria cronica della pelle, caratterizzata da cicli alternati di esacerbazioni\\u000a e stati clinici silenti. È stata definita come un problema di sanità pubblica a livello mondiale. Dati epidemiologici rilevano\\u000a una prevalenza compresa tra il 10% ed il 20% dei bambini, con variabilità in funzione dell’area geografica e dell’età. La\\u000a variabilità sarebbe legata non

Carlo Gelmetti

94

Light curves of DP CVn and DI Psc (Kovari+, 2013)  

NASA Astrophysics Data System (ADS)

Differential photometric magnitudes of DP CVn and DI Psc obtained with 'Wolfgang' (in Stroemgren b, y) and 'Amadeus' (in Johnson-Cousins V, Ic), the two automated photoelectric telescopes owned by the Leibniz-Institute for Astrophysics Potsdam (formerly of University of Vienna), located at Fairborn Observatory in Arizona, USA. Comparison stars were HD1095129 (for DP CVn) and HD217019 (for DI Psc). (8 data files).

Kovari, Zs.; Korhonen, H.; Strassmeier, K. G.; Weber, M.; Kriskovics, L.; Savanov, I.

2013-01-01

95

Synthesis, physicochemical, and tribological characterization of S-Di-n-octoxyboron-O,O'-di-n-octyldithiophosphate.  

PubMed

Dialkyldithiophosphates (DTPs) of zinc(II), copper(II), and other metals have been extensively used as multifunctional additives in lubricants to control friction and reduce wear in mechanical systems. Among these DTP compounds, zinc dialkyldithiophosphates (ZnDTPs) are the most common additives extensively used for more than 60 years. These additives form a protective film on steel surfaces and, thus, control friction and reduce wear. However, ZnDTPs contain zinc and large amounts of phosphorus and sulfur, which impair the environment, both directly and indirectly, by adversely affecting the performance of catalytic converters of various automobiles. For this reason, environmental legislation imposes limitations on concentrations of phosphorus, sulfur, and zinc in the lubricants. In this work, we report on zinc-free S-di-n-octoxyboron-O,O'-di-n-octyldithiophosphate (DOB-DTP) lubricant additive with amount of phosphorus and sulfur reduced by half in a molecule as compared with ZnDTPs. DOB-DTP was synthesized by a reaction in two steps under inert nitrogen atmosphere. The final product, a viscous liquid, was characterized by the elemental analysis, FT-IR, multinuclear (1)H, (13)C, (31)P, and (11)B NMR spectroscopy and thermal analyses. Tribological performance of a mineral oil with this new additive was evaluated in comparison with O,O'-di-n-butyl-dithiophosphato-zinc(II) (ZnDTP) using a four-ball tribometer. The surface morphology and the elemental composition of the tribofilms were characterized using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS). The results show that DOB-DTP has a considerably better antiwear performance and higher stability of the coefficient of friction with time as compared with ZnDTP. Both phosphorus and sulfur were detected by the EDS on the worn steel surfaces at all concentrations of additives in the base oil. PMID:20356164

Shah, Faiz Ullah; Glavatskih, Sergei; Antzutkin, Oleg N

2009-12-01

96

Bis(2,3-di-chloro-phen-yl) di-sulfide  

PubMed Central

The title compound, C12H6Cl4S2, features an S—S bond [2.0252?(8)?Å] that bridges two 2,3-di­chloro­phenyl rings with a C—S—S—C torsion angle of 88.35?(11)°. The benzene rings are normal one to the other with a dihedral angle of 89.83?(11)°. The crystal structure features inter­molecular Cl?Cl [3.4763?(11)?Å] and ?–? stacking inter­actions [centroid–centroid distances = 3.696?(1) and 3.641?(2)?Å]. Intra­molecular C—H?S inter­actions are also observed.

Osorio-Yanez, Rebeca Nayely; Crisostomo-Lucas, Carmela; Santacruz-Juarez, Ericka; Reyes-Martinez, Reyna; Morales-Morales, David

2014-01-01

97

Asteroidi  

NASA Astrophysics Data System (ADS)

Contents: Parte I: Asteroidi. 1. Introduzione. 2. Dinamica degli asteroidi. 3. Distribuzione degli asteroidi. 4. Proprietà fisiche degli asteroidi. 5. Interrelazioni nel Sistema Solare. Parte II: Le Osservazioni. 6. La pianificazione. 7. Astrometria. 8. Fotometria. Appendici: A. Tempo delle Effemeridi e Tempo Universale. B. Calcolo Effemeridi. C. Guida all'utilizzo del Minor Planet Software rel. 8. D. Determinazione della Coordinate Geografiche di una postazione di osservazione dalle Coordinate Metriche U.T.M. nella principale cartografia italiana.

Foglia, Sergio; Morbidelli, Alessandro; Masi, Gianluca; Carusi, Andrea

2006-10-01

98

The interphase in phenol–formaldehyde and polymeric methylene di-phenyl-di-isocyanate glue lines in wood  

Microsoft Academic Search

It has been proposed in the literature that the penetration of resin compounds into the wood cell wall may enhance the durability of adhesive bonds. In the study presented here, the diffusion of resin compounds into the cell wall of two systems, phenol–formaldehyde (PF) and polymeric methylene di-phenyl-di-isocyanate (pMDI), respectively, was evaluated making use of the UV-absorbance typical for both

Wolfgang Gindl; Thomas Schöberl; George Jeronimidis

2004-01-01

99

Biosynthesis of di-(2-ethylhexyl) phthalate (DEHP) and di- n-butyl phthalate (DBP) from red alga— Bangia atropurpurea  

Microsoft Academic Search

The contents of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) of red alga, Bangia atropurpurea, filaments cultured in artificial sea water medium were similar to those cultured in natural sea water medium. In the culture experiment, B. atropurpurea filaments were found to synthesize de novo phthalate esters. Additionally, DEHP and DBP contents in different species of algae grown in the

Chih Yu Chen

2004-01-01

100

Subchronic oral toxicity of di- n-octyl phthalate and di(2-ethylhexyl) phthalate in the rat  

Microsoft Academic Search

The subchronic oral toxicity of di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP) was studied. Groups of 10 male and 10 female Sprague-Dawley rats were administered DEHP in the diet at 0, 5, 50, 500 or 5000 ppm for 13 wk. In a separate study, groups of 10 male and 10 female Sprague-Dawley rats were given DNOP (5, 50, 500 and

R. Poon; P. Lecavalier; R. Mueller; V. E. Valli; B. G. Procter; I. Chu

1997-01-01

101

Biosynthesis of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) from red alga--Bangia atropurpurea.  

PubMed

The contents of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) of red alga, Bangia atropurpurea, filaments cultured in artificial sea water medium were similar to those cultured in natural sea water medium. In the culture experiment, B. atropurpurea filaments were found to synthesize de novo phthalate esters. Additionally, DEHP and DBP contents in different species of algae grown in the same environment were different significantly, suggesting that it was due to the intrinsic nature of algae. PMID:14769421

Chen, Chih Yu

2004-02-01

102

Stato dell'arte della regolamentazione del verde urbano in Italia. Prima indagine sui comuni capoluogo di provincia  

Microsoft Academic Search

Riassunto Nei capoluoghi di provincia esaminati (l'84 % degli esistenti), frequenti sono le norme di diverso genere (regolamenti di settore, ordinanze sindacali, deliberazioni comunali, norme di carattere edilizio ed urbanistico) che riguardano la realizzazione e gestione del verde urbano. Mentre la diffusione di regolamenti propriamente detti risulta essere ancora inferiore al 20 %, quasi il 3\\/4 delle amministrazioni censite hanno

Giovanni Sanesi

103

Migration of Di- and Tri-Interstitials in Silicon  

SciTech Connect

A comprehensive study on the migration of di- and tri-interstitials in silicon is performed using classical molecular dynamics simulations with the Stillinger-Weber potential. The initial di- and tri-interstitial configurations with the lowest formation energies are determined, and then, the defect migration is investigated for temperatures between 800 and 1600 K. The defect diffusivity and the self-diffusion coefficient per defect are calculated. Compared to the mono-interstitial, the di-interstitial migrates faster, whereas the tri-interstitial diffuses slower. The migration mechanism of the di-interstitial shows a pronounced dependence on the temperature. Like in the case of the mono-interstitial, the mobility of the di-interstitial is higher than the mobility of the lattice atoms during the defect diffusion. On the other hand, the tri-interstitial mobility is lower than the corresponding atomic mobility. The results are compared with data from the literature and the implications of the present results for the analysis of experimental data on defect evolution and migration are discussed.

Posselt, Matthias; Gao, Fei; Zwicker, D

2005-01-01

104

Tetrakis(2,6-di-methyl-pyridinium) di-hydrogen deca-vanadate dihydrate.  

PubMed

The structure of the title compound, (C7H10N)4[H2V10O28]·2H2O, was solved from a non-merohedrally twinned crystal (ratio of twin components ?0.6:0.4). The asymmetric unit consists of one-half deca-vanadate anion (the other half completed by inversion symmetry), two 2,6-di-methyl-pyridinium cations and one water mol-ecule of crystallization. In the crystal, the components are connected by strong N-H?O and O-H?O hydrogen bonds, forming a supra-molecular chain along the b-axis direction. There are weak C-H?O inter-actions between the chains. PMID:24940209

Rakovský, Erik; Krivosudský, Lukáš

2014-06-01

105

Tetrakis(2,6-di-methyl-pyridinium) di-hydrogen deca-vanadate dihydrate  

PubMed Central

The structure of the title compound, (C7H10N)4[H2V10O28]·2H2O, was solved from a non-merohedrally twinned crystal (ratio of twin components ?0.6:0.4). The asymmetric unit consists of one-half deca­vanadate anion (the other half completed by inversion symmetry), two 2,6-di­methyl­pyridinium cations and one water mol­ecule of crystallization. In the crystal, the components are connected by strong N—H?O and O—H?O hydrogen bonds, forming a supra­molecular chain along the b-axis direction. There are weak C—H?O inter­actions between the chains.

Rakovsky, Erik; Krivosudsky, Lukas

2014-01-01

106

Analysis of lustred ceramics of the Galleria Regionale di Palazzo Bellomo di Siracusa, Italy  

NASA Astrophysics Data System (ADS)

Several fragments of lustred pottery coming from the collection of the Galleria Regionale di Palazzo Bellomo and excavated in Siracusa, were studied through non-invasive ion beam techniques in the Centre de Recherche et de Restauration des Musees de France in Paris. Up to now only aesthetic and stylistic analysis were available for these objects, and their provenances and dating were unknown or uncertain; moreover, the question concerning a possible local production was still debated. Compositions of pottery and glazed parts were thus obtained by Particle Induced X-ray Emission analysis, while the depth distribution of element of the lustre was analyzed by the Rutherford Backscattering Spectrometry technique. The obtained results provided important information on possible origin and production period of the objects.

Politi, Giuseppe; Bouquillon, Anne; Aucouturier, Marc; Gueli, Anna; Troja, Sebastiano Olindo; Vella, Carmela; Pacheco, Claire; Pichon, Laurent; Moignard, Brice; Lemasson, Quentin

2014-07-01

107

Penta-aqua-(di-methyl-formamide)-cobalt(II) sulfate di-methyl-formamide monosolvate  

PubMed Central

The title compound, [Co(C3H7NO)(H2O)5]SO4·C3H7NO, contains five aqua ligands, a CoII atom, a sulfate ion and both a coordinating and a non-coordinating di­methyl­formamide (DMF) mol­ecule. The DMF solvent mol­ecule lies between the complex units, which are located along the b axis. The sulfate ion is for charge balance. The CoII atom has distorted octa­hedral coordination geometry, being ligated by five aqua ligands and the O atom of the DMF ligand. O—H?O hydrogen bonds between the aqua ligands and the sulfate anion and non-coordinating DMF molecule lead to the formation of a three-dimensional network. Since all constituents lie on a mirror plane, the H atoms of all methyl groups and of one of the aqua ligands are equally disordered over two positions.

Tas, Murat; Camur, Seval; Topal, Sevim

2013-01-01

108

Biological effects summary report di(2-ethylhexyl) sebacate  

SciTech Connect

An evaluation of the health effects of di(2-ethylhexyl) sebacate (DEHS) was made to assess its potential use as substitute for di(2-ethylhexyl) phthalate (DEHP), which is used as a test aerosol in quantitative fit testing of respirators. A review of published and unpublished information on toxicity of DEHS was made. The limited amount of data on DEHS indicated that it has a low level of toxicity to laboratory animals. No oral or inhalation toxicity studies on humans were found, but skin sensitization and irritation studies were negative. Insufficeint data exists at present to permit determination of DEHS carcinogenicity. Because of structural similarities of DEHS to DEHP and di(ethylhexyl) adipate, and because these latter two materials have been shown to be carcinogenic in rats and mice, DEHS is not recommended at this time as a DEHP substitute until lack of its carcinogenic potential is confirmed.

Silverstein, B.D.; White, O. Jr.; Brower, J.E.; Bernholc, N.M.

1983-10-01

109

40 CFR 721.8225 - 2-Propenamide, N-[3-di- methyl-amino)propyl]-.  

Code of Federal Regulations, 2013 CFR

... false 2-Propenamide, N-[3-di- methyl-amino)propyl]-. 721.8225 Section 721.8225 Protection of Environment...8225 2-Propenamide, N -[3-di- methyl-amino)propyl]-. (a) Chemical substance and significant new uses...

2013-07-01

110

Visualizing the perturbation of cellular cyclic di-GMP levels in bacterial cells.  

PubMed

Cyclic di-GMP (c-di-GMP) has emerged as a prominent intracellular messenger that coordinates biofilm formation and pathogenicity in many bacterial species. Developing genetically encoded biosensors for c-di-GMP will help us understand how bacterial cells respond to environmental changes via the modulation of cellular c-di-GMP levels. Here we report the design of two genetically encoded c-di-GMP fluorescent biosensors with complementary dynamic ranges. By using the biosensors, we found that several compounds known to promote biofilm dispersal trigger a decline in c-di-GMP levels in Escherichia coli cells. In contrast, cellular c-di-GMP levels were elevated when the bacterial cells were treated with subinhibitory concentrations of biofilm-promoting antibiotics. The biosensors also revealed that E. coli cells engulfed by macrophages exhibit lower c-di-GMP levels, most likely as a response to the enormous pressures of survival during phagocytosis. PMID:23289502

Ho, Chun Loong; Chong, Kavin Shi Jie; Oppong, Jamila Akosua; Chuah, Mary Lay Cheng; Tan, Suet Mien; Liang, Zhao-Xun

2013-01-16

111

Di-Neutron Correlation in Light Neutron-Rich Nuclei  

NASA Astrophysics Data System (ADS)

Using a three-body model with density-dependent contact interaction, we discuss the root mean square distance between the two valence neutrons in 11Li nuclues as a function of the center of mass of the neutrons relative to the core nucleus 9Li. We show that the mean distance takes a pronounced minimum around the surface of the nucleus, indicating a strong surface di-neutron correlation. We demonstrate that the pairing correlation plays an essential role in this behavior. We also discuss the di-neutron structure in the 8He nucleus.

Hagino, K.; Sagawa, H.; Schuck, P.

112

Target Search and Selection for the DI/EPOXI Spacecraft  

NASA Technical Reports Server (NTRS)

Upon completion of the Hartley 2 flyby in November 2010, the Deep Impact (DI) spacecraft resided in a solar orbit without possibility for gravity assist with any large body. Conservative estimates of remaining fuel were enough to provide only an 18 m/s impulse on the spacecraft. We present our method and results of our systematic scan of potential small body encounters for DI, and our criteria to narrow the selection to the asteroid 2002 GT as the target flyby body. The mission profile has two deterministic maneuvers to achieve the encounter, the first of which executed on November 25, 2011.

Grebow, Daniel J.; Bhaskaran, Shyam; Chesley, Steven R.

2012-01-01

113

Evidenze di disturbi sistemici nelle insonnie: le patologie cardio-cerebrovascolari  

Microsoft Academic Search

Riassunto Alcune ricerche epidemiologiche hanno evi- denziato che l'insonnia si associa ad un importante aumento della comorbilità internistica. Non sempre sono disponibili studi prospettici che consentono di compren- dere se l'insonnia è il risultato o la causa di patologie internistiche. Bisogna comunque considerare l'insonnia (o la privazione di sonno) e il funzionamento di due diversi sistemi: quello ormonale e quello

PROGETTO MORFEO

2006-01-01

114

Structural basis of ligand binding by a c-di-GMP riboswitch  

Microsoft Academic Search

The second messenger signaling molecule bis-(3?-5?)-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates many processes in bacteria, including motility, pathogenesis and biofilm formation. c-di-GMP–binding riboswitches are important downstream targets in this signaling pathway. Here we report the crystal structure, at 2.7 Å resolution, of a c-di-GMP riboswitch aptamer from Vibrio cholerae bound to c-di-GMP, showing that the ligand binds within a three-helix

Kathryn D Smith; Sarah V Lipchock; Tyler D Ames; Jimin Wang; Ronald R Breaker; Scott A Strobel

2009-01-01

115

Synthesis and photochemical properties of 1,3-di-9-anthryl-2-propanol, 1,3-di-9-anthrylacetone, and related propano-linked anthracenes  

SciTech Connect

9-anthryllithium reacts with epichlorohydrin to give 1,3-di-9-anthryl-2-propanol via 3-(9-anthryl)-1-chloro-2-hydroxypropane and 3-(9-anthryl)-1,2-epoxypropane. Oxidation of dianthryl-2-propanol with Dess-Martin reagent gave 1,3-di-9-anthrylacetone. Various other 1,3-bichromophoric anthracenes were synthesized by way of C-methylation of dianthrylacetone, 1,3-di-9-anthryl-1-propanone, and 1,3-di-9-anthrylpropenone. 9-Anthrylacetone, formed as byproduct in the reaction of anthryllithium with epichlorohydrin, was prepared from 9-anthrylacetaldehyde by Grignard reaction with methylmagnesium iodide and subsequent oxidation. The excited-state properties of dianthryl-2-propanol, dianthrylacetone, 1,3-di-9-anthryl-2-methyl-1-propanone, 1,3-di-9-anthryl-2-methyl-2-propanol, diastereomeric 1,3-di-9-anthryl-1-butanols, 1,3-di-9-anthryl-2-butanone, 1,3-di-9-anthryl-1-butanone, and diastereomeric 1,3-di-9-anthryl-2-methyl-1-butanones have been evaluated by fluorescence quantum yields, and by quantum yields for the isomerization by intramolecular 4{pi} + 4{pi} cycloaddition. Dianthryl-2-propanol, 1,3-di-9-antrhyl-2-methyl-2-propanol, dianthrylacetone, diastereomeric 1,3-di-9-anthryl-1-butanols, and 1,3-di-9-anthryl-2-butanone isomerize in their excited singlet state with quantum yields of 0.046, 0.021, 0.25, 0.23, and 0.22, respectively. The photochemical isomerization of those 1,3-bichromophoric anthrancenes which are characterized by a 9-anthroyl chromophore involves the excited triplet state, and the cyclization quantum yield may be as high as 0.72.

Becker, H.D.; Amin, K.A. (Chalmers Univ. of Technology, Gothenburg (Sweden))

1989-06-23

116

Exploring environmental control of cyclic di-GMP signaling in Vibrio cholerae by using the ex vivo lysate cyclic di-GMP assay (TELCA).  

PubMed

Vibrio cholerae senses its environment, including the surrounding bacterial community, using both the second messenger cyclic di-GMP (c-di-GMP) and quorum sensing (QS) to regulate biofilm formation and other bacterial behaviors. Cyclic di-GMP is synthesized by diguanylate cyclase (DGC) enzymes and degraded by phosphodiesterase (PDE) enzymes. V. cholerae encodes a complex network of 61 enzymes predicted to mediate changes to the levels of c-di-GMP in response to extracellular signals, and the transcription of many of these enzymes is influenced by QS. Because of the complexity of the c-di-GMP signaling system in V. cholerae, it is difficult to determine if modulation of intracellular c-di-GMP in response to different stimuli is driven primarily by changes in c-di-GMP synthesis or hydrolysis. Here, we describe a novel method, named the ex vivo lysate c-di-GMP assay (TELCA), that systematically measures total DGC and PDE cellular activity. We show that V. cholerae grown in different environments exhibits significantly different intracellular levels of c-di-GMP, and we used TELCA to determine that these differences correspond to changes in both c-di-GMP synthesis and hydrolysis. Furthermore, we show that the increased concentration of c-di-GMP at low cell density is primarily due to increased DGC activity due to the DGC CdgA. Our findings highlight the idea that modulation of both total DGC and PDE activity alters the intracellular concentration of c-di-GMP, and we present a new method that is widely applicable to the systematic analysis of complex c-di-GMP signaling networks. PMID:23793642

Koestler, Benjamin J; Waters, Christopher M

2013-09-01

117

MISURA, DOCUMENTAZIONE, RAPPRESENTAZIONE: STUDI PER L'ORGANIZZAZIONE DI UN SISTEMA INFORMATIVO REFERENZIATO. L'INSULA 104 NELLA REGIO VIII DELL'ANTICA CITTA' DI HIERAPOLIS DI FRIGIA (TURCHIA)  

Microsoft Academic Search

Nel campo delle tematiche archeologiche, le potenzialità che provengono dallo sviluppo informatico e dalle reti di telecomunicazioni hanno condotto ad un'azione sempre più interdisciplinare ai fini della documentazione, archiviazione e comunicazione delle attività coinvolte in un quadro di tutela, conservazione e valorizzazione dei beni. L'avvicinamento dell'Archeologia alla Geomatica e agli strumenti di gestione dei dati spaziali, e viceversa, è sentito

C. Bonfanti

118

Metodi radiometrici di misura delle acque potabili: esperienze e nuovi sviluppi  

Microsoft Academic Search

Il monitoraggio radiometrico delle acque potabili assume oggi particolare importanza anche alla luce delle nuove regolamentazioni nazionali ed internazionali. La molteplicità dei parametrici analitici necessari ad una completa definizione della qualità radiometrica dell'acqua e l'onerosità di questo tipo di misure rende necessaria una attenta valutazione preliminare che tenga conto del livello di dettaglio e delle sensibilità richieste, delle potenzialità strumentali

Maurizio Forte; Rosella Rusconi; Silvia Bellinzona; Maria Teresa Cazzaniga; Giuseppe Sgorbati

119

Mission, strategie e valutazione delle performance delle aziende nonprofit in un approccio di stakeholder management  

Microsoft Academic Search

Le aziende non profit (anp) sono particolari organizzazioni che hanno come obiettivo istituzionale non la creazione di profitto in senso economico ma la massimizzazione del valore sociale prodotto a vantaggio della collettività di riferimento. Tale valore è di natura intangibile e la sua definizione e misurazione dipendono in maniera fondamentale dalla percezione dei diversi stakeholder da esso a vario titolo

Ericka Costa; Tommaso Ramus

2010-01-01

120

Immunoglobulin deficiencies: the B-lymphocyte side of DiGeorge Syndrome.  

PubMed

DiGeorge syndrome is associated with a T-lymphocyte immunodeficiency. The prevalence of hypogammaglobulinemia has not been reported. We found that 3% of patients with DiGeorge syndrome were receiving immunoglobulin replacement therapy and 6% of patients over the age of 3 years had hypogammaglobulinemia. We conclude that DiGeorge syndrome is associated with significant humoral immune deficiency. PMID:22809661

Patel, Kiran; Akhter, Javeed; Kobrynski, Lisa; Benjamin Gathmann, M A; Gathman, Benjamin; Davis, Onika; Sullivan, Kathleen E

2012-11-01

121

Synthesis of new heteroaryldi(diindolyl)methanes: Colorimetric detection of DNA by di(diindolylmethyl)carbazoles  

Microsoft Academic Search

We have synthesized di(diindolylmethyl)carbazoles and di(diindolylmethyl)pyrroles by the reaction of substituted indoles with\\u000a the corresponding carbazole and pyrroledicarboxaldehydes by employing a new catalyst PPh3.CF3SO3H. We have also demonstrated the utility of di(diindolylmethyl) carbazole derivatives for the colourimetric and fluorometric\\u000a detection of DNA.

Ramu Meesala; Rajagopal Nagararajan

2009-01-01

122

Anaerobic degradation of diethyl phthalate, di- n-butyl phthalate, and di-(2-ethylhexyl) phthalate from river sediment in Taiwan  

Microsoft Academic Search

We investigated anaerobic degradation rates for three phthalate esters (PAEs), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di-(2-ethylhexyl) phthalate (DEHP), from river sediment in Taiwan. The respective anaerobic degradation rate constants for DEP, DBP, and DEHP were observed as 0.045, 0.074, and 0.027 1\\/day, with respective half-lives of 15.4, 9.4, and 25.7 days under optimal conditions of 30°C and pH7.0.

B. V. Chang; C. S. Liao; S. Y. Yuan

2005-01-01

123

Extraction of acids with DI-(2,4-diethyloctyl) amine  

SciTech Connect

The authors explain how being bases, amines extract acids by neutralization with the formation of the corresponding salts. This investigation describes a study of the extraction of mineral acids, and the measurement of the extraction constants. The extractant used was di-(2,4-diethyloctyl) amine, which is a secondary amine with a branched radical at the nitrogen atom.

Ul'yanov, V.S.; Sidorova, O.P.; Sokal'skaya, L.I.; Sviridova, R.A.; Tarasova, N.A.

1986-03-01

124

PLCs, DI, & RTI: A Tapestry for School Change  

ERIC Educational Resources Information Center

Rather than buying individual books about professional learning communities (PLCs), differentiated instruction (DI), and Response to Intervention (RTI), invest wisely in one resource that synthesizes all three. The text uses a tapestry analogy to weave together these critical topics to form a comprehensive framework for achieving continuous school…

Stoehr, Judy; Banks, Maria; Allen, Linda

2011-01-01

125

DiVerential integration of kinaesthetic signals to postural control  

Microsoft Academic Search

The purpose of the present experiment was to identify whether non-visual sensory cues involved in the maintenance of balance control could be weighted diVerently from one subject to another in condition during which kinaesthetic signals, stemming from the ankle proprioceptors and plantar pressure somatosensory sensors, were altered. A large popula- tion of blindfolded healthy young university students (n = 140)

Brice Isableu; Nicolas Vuillerme

126

Molecular organization in perylene tetracarboxylic di-imide solid films  

NASA Astrophysics Data System (ADS)

The vibrational spectra of thin solid films of three perylene tetracarboxylic di-imide derivatives (phenyl, methyl, and unsubstituted) are reported. A preferred molecular orientation in the evaporated solid films emerged for all three perylene derivatives from the i.r. data. Raman spectra obtained in resonance with the absorption band were characteristic of scattering via a Herzberg—Teller mechanism.

Akers, K.; Aroca, R.; Hort, A. M.; Loutfy, R. O.

127

di\\/dt Noise in CMOS Integrated Circuits  

Microsoft Academic Search

This is an overview paper presenting di\\/dtnoise from a designer‘s perspective. Analysis and circuit designtechniques are presented taking package parasitics into account.The main focus is on digital CMOS design, but analysis and designsuggestions can easily be extended to mixed-mode design.

Patrik Larsson

1997-01-01

128

Let's Talk Credentialing: An Interview with Mary DiGiovanni.  

ERIC Educational Resources Information Center

Presents an interview with the President of the Council for Standards in Human Service Education. Discusses DiGiovanni's participation in the development of the human service field on a national level, and involvement with the standardization of human service competencies as well as the credentialing of human service professionals. (Author/GCP)

McClam, Tricia

1999-01-01

129

Chemiluminescent emission spectra of tin mono- and di-halides  

Microsoft Academic Search

Chemiluminescent emission from flames of tin halides burning at low pressure in potassium vapor is found to include vibronic bands of mono- and di-halides. The emitters are, quite certainly, electrically neutral species. Bands from SnCl2 are analyzed with the aid of a Deslandres scheme and some vibrational constants are assigned to the upper and lower states.

David Naegeli; Howard B. Palmer

1966-01-01

130

ViDiO - Visual Distribution of Objects  

Microsoft Academic Search

The authors present a tool: Visual Distribution of Objects (ViDiO), for graphical deployment of CORBA objects. It allows easy association of hosts with IDL interfaces and produces client, server, and object code in Java based on the drawn diagram and provided XML based templates. It is based on a library designed for platform independent display of computer networks

Markus Aleksy; Ralf Gitzel

2001-01-01

131

Microbial degradation of di-n-butyl phthalate  

Microsoft Academic Search

Microorganisms capable of degrading di-n-butyl phthalate (DBP) were isolated. The characteristics of DBP biodegradation by immobilized and free cells were investigated. The experimental results showed that the rate of DBP degradation of immobilized cells was higher than that of free cells.

Wang Jianlong; Liu Ping; Qian Yi

1995-01-01

132

URINARY METABOLITES OF DI-N-OCTYL PHTHALATE IN RATS  

EPA Science Inventory

Di-n-octyl phthalate (DnOP) is a plasticizer used in polyvinyl chloride plastics, cellulose esters, and polystyrene resins. The metabolism of DnOP results in the hydrolysis of one ester linkage to produce mono-n-octyl phthalate (MnOP), which subsequently metabolizes to form oxida...

133

TOXICOLOGY OF MONO- AND DI-ALKYLTIN CHLORIDES  

EPA Science Inventory

Mono- and di-alkyltin chlorides are reactive compounds used in the production of stabilizers for polyvinyl chloride (PVC) plastics, primarily used for water distribution pipes. Health effects data were compiled or developed by the manufacturers for the EPA's HPV Challenge progra...

134

TOXICOLOGY OF MONO- AND DI-ALKYLTIN CHLORIDES.  

EPA Science Inventory

Mono- and di-alkyltin chlorides are reactive compounds used in the production of stabilizers for polyvinyl chloride (PVC) plastics, primarily used for water distribution pipes. Health effects data were compiled or developed by the manufacturers for the EPA's HPV Challenge progra...

135

Conditional Transgenesis Using Dimerizable Cre (DiCre)  

PubMed Central

Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. We have recently developed a conceptually new approach to regulate Cre recombinase, that we have called Dimerizable Cre or DiCre. It is based on splitting Cre into two inactive moieties and fusing them to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12-rapamycin associated protein), respectively. These latter can be efficiently hetero-dimerized by rapamycin, leading to the reinstatement of Cre activity. We have been able to show, using in vitro approaches, that this ligand-induced dimerization is an efficient way to regulate Cre activity, and presents a low background activity together with a high efficiency of recombination following dimerization. To test the in vivo performance of this system, we have, in the present work, knocked-in DiCre into the Rosa26 locus of mice. To evaluate the performance of the DiCre system, mice have been mated with indicator mice (Z/EG or R26R) and Cre-induced recombination was examined following activation of DiCre by rapamycin during embryonic development or after birth of progenies. No recombination could be observed in the absence of treatment of the animals, indicating a lack of background activity of DiCre in the absence of rapamycin. Postnatal rapamycin treatment (one to five daily injection, 10 mg/kg i.p) induced recombination in a number of different tissues of progenies such as liver, heart, kidney, muscle, etc. On the other hand, recombination was at a very low level following in utero treatment of DiCre×R26R mice. In conclusion, DiCre has indeed the potentiality to be used to establish conditional Cre-deleter mice. An added advantage of this system is that, contrary to other modulatable Cre systems, it offers the possibility of obtaining regulated recombination in a combinatorial manner, i.e. induce recombination at any desired time-point specifically in cells characterized by the simultaneous expression of two different promoters.

Jullien, Nicolas; Goddard, Isabelle; Selmi-Ruby, Samia; Fina, Jean-Luc; Cremer, Harold; Herman, Jean-Paul

2007-01-01

136

Considerazioni generali sull’impostazione Bayesiana di problemi non parametrici. Le medie associative nel contesto del processo aleatorio di Dirichlet parte II  

Microsoft Academic Search

Nei problemi statistici non parametrici la conoscenza della distribuzione iniziale e finale di una generica media associativa\\u000a si manifesta particolarmente utile. Se la classe delle possibili funzioni di ripartizione scelte per descrivere un fenomeno\\u000a retta da un processo di Dirichlet nel senso precisato in D. M. Cifarelli — E. Regazzini (1979), possibile pervenire ad\\u000a una rappresentazione esplicita della distribuzione iniziale

Donato Michele Cifarelli; Eugenio Regazzini

1979-01-01

137

Occupational exposure to diisononyl phthalate (DiNP) in polyvinyl chloride processing operations  

Microsoft Academic Search

Purpose  Diisononyl phthalate (DiNP) is primarily used as a plasticizer in polyvinyl chloride (PVC) materials. While information is\\u000a available on general population exposure to DiNP, occupational exposure data are lacking. We present DiNP metabolite urinary\\u000a concentrations in PVC processing workers, estimate DiNP daily intake for these workers, and compare worker estimates to other\\u000a populations.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We assessed DiNP exposure in participants from

Cynthia J. Hines; Nancy B. Hopf; James A. Deddens; Manori J. Silva; Antonia M. Calafat

138

RATE CONSTANTS FOR THE REACTIONS OF OH RADICALS AND CL ATOMS WITH DI-N-PROPYL ETHER AND DI-N-BUTYL ETHER AND THEIR DEUTERATED ANALOGS. (R825252)  

EPA Science Inventory

Using relative rate methods, rate constants for the gas-phase reactions of OH radicals and Cl atoms with di- n -propyl ether, di- n -propyl ether-d14, di- n -butyl ether and di- n -butyl ether-d18 have been measured at 296 ? 2 K and atmos...

139

Dimethyl 6-iodo-2-methyl-1,2-di-hydro-quinoline-2,4-di-carboxyl-ate  

PubMed Central

In the title compound, C14H14INO4, the di­hydro­pyridine ring adopts a twist conformation. In the crystal, pairs of N—H?O and C—H?O hydrogen bonds link the mol­ecules into inversion R 2 2(10) and R 2 2(18) dimers, forming infinite double chains running along the c axis.

Gultekin, Zeynep; Frey, Wolfgang; Hokelek, Tuncer

2013-01-01

140

Truncated form of the title: Mechanism of c-di-GMP signaling  

PubMed Central

Summary Cyclic dimeric guanosine monophosphate (c-di-GMP) is a common, bacterial second messenger that regulates diverse cellular processes in bacteria. Opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) control c-di-GMP homeostasis in the cell. Many microbes have a large number of genes encoding DGCs and PDEs that are predicted to be part of c-di-GMP signaling networks. Other building blocks of these networks are c-di-GMP receptors which sense the cellular levels of the dinucleotide. C-di-GMP receptors form a more diverse family, including various transcription factors, PilZ domains, degenerate DGCs or PDEs, and riboswitches. Recent studies revealing the molecular basis of c-di-GMP signaling mechanisms enhanced our understanding of how this molecule controls downstream biological processes and how c-di-GMP signaling specificity is achieved.

Sondermann, Holger; Shikuma, Nicholas J.; Yildiz, Fitnat H.

2012-01-01

141

Il raffreddamento a impulsi offre un'interessante possibilità di raffreddare uno stampo in modo uniforme. L' articolo illustra le potenzialità di questa tecnologia con i risultati di alcune simulazioni agli elementi finiti  

Microsoft Academic Search

Come noto, gli stampi per lo stampaggio dei termoplastici ricevono calore dal materiale iniettato in un processo discontinuo e, tipicamente, lo cedono al sistema di raffreddamento in un processo continuo. La temperatura della superficie delle cavità dello stampo viene in questo modo determinata primariamente dalla temperatura del mezzo di raffreddamento, ammessa una portata sufficiente. In alternativa a questa metodologia si

H. Schirrmacher

142

Periodici in Scambio con gli 'Annali dell'Istituto Superiore di Sanita': Quale Ruolo in Epoca di Open Access (Periodicals in Exchange with 'Annali dell'Istituto Superiore di Sanita': Which Role in the Open Access Era).  

National Technical Information Service (NTIS)

This report covers the detailed review work done by the Editorial Unit of the Istituto Superiore di Sanita (ISS) on all the journals received through its exchange programme with the quarterly periodical Annali dellIstituto Superiore di Sanita. It gives a ...

F. Napolitani L. Radiciotti M. G. Corsi

2007-01-01

143

LA BANCA DATI METEOROLOGICA STORICA DELLA REGIONE ABRUZZO: RICERCA DI UN METODO PER RAPPRESENTARE I DATI RILEVATI A FINI AGRONOMICI  

Microsoft Academic Search

Il lavoro riporta un'attività di servizio, finalizzata alla diffusione dei dati meteorologici archiviati presso le banche dati del Centro a supporto di Progetti di ricerca e sperimentazione attinenti ai diversi Servizi dell'Agenzia. L'elaborazione del regime termo-pluviomertrico per alcune località della piana del Fucino (Altopiano interno in provincia dell'Aquila), utilizzando alcuni metodi semplici di statistica descrittiva, ha consentito di ottenere report

144

The gas-phase structures of some highly strained compounds: di- t-butylmethane, di- t-butylamine and di- t-butyl ketone  

NASA Astrophysics Data System (ADS)

The geometric structures of di- t-butylmethane (DTBM) and di- t-butylamine (DTBA) have been reinvestigated by gas-phase electron diffraction (GED). In addition to these two compounds, di- t-butyl ketone (DTBK) has been studied by the same technique. The steric strain caused by the two adjacent t-butyl groups leads only to a slight lengthening of the central X?C bonds (X ?C or N) of about 0.01-0.02 Å relative to the corresponding methyl derivatives. The central bond angles, however, increase strongly: CCC = 123.3 (18)° in DTBM, CNC = 129.0 (20)° in DTBA and CCC = 124.9 (15)° in DTBK. The t-butyl groups are tilted away from each other by 5.6 (8)° in DTBM and 5.8 (7)° in DTBA. Only a small tilt of 1.6 (12)° is observed in DTBK. The t-butyl groups are rotated around the X?C bond away from the positions in which both groups eclipse each other (or each group staggers the opposite X?C bond) by 17 (3), 15 (3) and 27 (3)° in DTBM, DTBA and DTBK, respectively. The experimental geometries are well reproduced by MM3 and ab initio calculations (HF/4-21 for DTBM and DTBA which have been reported in the literature, and HF/3-21 G for DTBK). The theoretical values for the central bond angles are in perfect agreement with the experiments, except for the MM3 values in DTBK, which is about 3° smaller than the GED and ab initio results. The large tilt angles in DTBM and DTBA are reproduced correctly by the ab initio calculations, but are slightly underestimated by the MM3 method.

Liedle, Siegfried; Oberhammer, Heinz; Allinger, Norman L.

1994-01-01

145

URINARY AND AMNIOTIC FLUID LEVELS OF PHTHALATE MONOESTERS IN RATS AFTER THE ORAL ADMINISTRATION OF DI(2-ETHYLHEXYL) PHTHALATE AND DI-N-BUTYL PHTHALATE  

EPA Science Inventory

Two studies were designed to examine amniotic fluid and maternal urine concentrations of the di(2-ethylhexyl) phthalate (DEHP) metabolite mono(2-ethylhexyl) phthalate (MEHP) and the di-n-butyl phthalate (DBP) metabolite monobutyl phthalate (MBP) after administration of DEHP and D...

146

(Z)-N-[(Z)-3-(2,5-Di-methyl-phenyl-imino)-butan-2-yl-idene]-2,5-di-methyl-aniline  

PubMed Central

The asymmetric unit of the title compound, C20H24N2, contains one half-mol­ecule, with the single C—C bond of the 1,4-di­aza­butadiene fragment situated on a centre of symmetry. The benzene rings are inclined to the 1,4-di­aza­butadiene mean plane by 59.5?(1)°.

Lv, Wen-Xian; Li, Jian; Hu, Yu-Lai; Su, Ying-Peng; Huang, Dan-Feng

2014-01-01

147

DiRecT: A disaster recovery system  

NASA Astrophysics Data System (ADS)

We describe the design and ongoing research of a Disaster Recovery System that features uncertainty visualization and distributed computing. Our system, DiRect, is intended for use by firefighters, policemen, and rescue personnel to aid in disaster recovery missions. These missions can run the gamut from natural disasters like earthquakes and fire to situations like 9/11. The use of visuals and a distributed communication infrastructure will help rescuers make better informed, more accurate and quicker decisions. In this paper, we discuss the need for such a system as well as the resulting infrastructure architecture we have developed. We further describe how information is collected using ICS (Incident Command System) protocol and is stored and fused. Finally we describe how this information will be visualized by the system. A goal of DiRect is to capture the uncertainties of the information and visually present this for more informed decisions. Current results are presented.

Grewe, Lynne L.; Krishnagiri, Shruti; Cristobal, John J.

2004-08-01

148

A novel method for monitoring tumor proliferation in vivo using fluorescent dye DiD.  

PubMed

Monitoring single cell proliferation in vivo is difficult, but optimizing this technique is essential in order to expand our knowledge of the regulation of tumor proliferation. In this study, we used a lipophilic fluorescent dye, DiD, that rapidly and stably integrates into the phospholipid cell membrane. We cultured DiD-stained prostate cancer cell lines for 10 days and isolated cells by flow cytometry based on expression levels of DiD. We found that a decrease in DiD intensity was correlated to the reduction of EdU, where the DiD-high population proliferated more slowly than the DiD-low population and the DiD-low population exhibited a higher mitotic index. We also found that DiD was detected after 3 weeks of implantation in an in vivo setting. Importantly, DiD dye did not have any effect on normal cell growth, whereas a gold standard fluorescent dye for measuring cell proliferation, CFSE, slowed cell proliferation. Although further study is indicated, DiD can be useful for identifying the molecular mechanisms underlying tumor proliferation in vivo. © 2014 International Society for Advancement of Cytometry. PMID:24700602

Yumoto, Kenji; Berry, Janice E; Taichman, Russell S; Shiozawa, Yusuke

2014-06-01

149

Photochemistry of amorphous 1,2-di-(?-naphthyl)ethylene  

NASA Astrophysics Data System (ADS)

Photochemical reactions of the amorphous cis- and trans-1,2-di-(?-naphthyl)ethylenes (D?NE) in hydrosols were studied. Besides the cis—trans-photoisomerization and photocyclization taking place in solution, the amorphous D?NE was found to undergo dimerization, in this case the dimer is formed only from trans-D?NE. Efficient electronic excitation transfer from the trans- to the cis-isomer was found to occur.

Rachinsky, A. G.; Razumov, V. F.

1994-03-01

150

Chronic Toxicity of Di(2-ethylhexyl)phthalate in Rats  

Microsoft Academic Search

Fischer 344 rats were treated with 0, 100, 500, 2500, or 12,500 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at weeks 26, 52, 78, and 104 from 10 animals per sex per group. Survival was slightly but not statistically reduced for rats receiving 12,500 ppm DEHP. Body weights and food consumption

Raymond M. David; Michael R. Moore; Dean C. Finney; Derek Guest

2000-01-01

151

Autoimmune pancytopenia in a child with DiGeorge syndrome  

Microsoft Academic Search

We report on the development of auto-immune pancytopenia in a child with DiGeorge syndrome carrying the 22q11 microdeletion. She had congenital heart disease, dysmorphic facies, thymic hypoplasia, immunodeficiency, velopharyngeal insufficiency, scoliosis, and a hearing deficit. She had a low T-cell count with a normal CD4\\/CD8 ratio, IgA deficiency and a normal lymphoblastic response to mitogens. She has presented with pancytopenia

Bénédicte Bruno; Catherine Barbier; Anne Lambilliotte; Christian Rey; Dominique Turck

2002-01-01

152

Synthesis and characterization of di-disubstituted phthalocyanines  

Microsoft Academic Search

An improved approach to the synthesis of di-disubstituted phthalocyanines from two different phthalyl precursors is described. The method combines substituted 1,3 diiminoisoindoles and 6\\/7-nitro-1,3,3-trichloroisoindolenine to synthesize phthalocyanine. The method can be applied to the synthesis of hydrogen and metallo phtahlocyanine. The yields are variable, ranging from 17% to 72% depending on the substituents.

Joseph G. Young; William Onyebuagu

1990-01-01

153

PVT properties of di-(2-ethyl hexyl) phosphoric acid  

Microsoft Academic Search

Di-(2-ethyl hexyl) phosphoric acid (hereafter referred as D2EHPA) is an important solvent for solvent extraction industry.\\u000a It is also used in nuclear solvent extraction as a solvent for TALSPEAK and REVERSED TALSPEAK processes for actinide (III)–lanthanide\\u000a (III) separation. Its PVT properties are not available in literature. In this work, group-contribution approach was used to\\u000a predict its PVT properties as well

Shekhar KumarS; S. Balasubramonian; D. Sivakumar; U. Kamachi Mudali; R. Natarajan

154

Di(hydroxyphenyl)- 1,2,4-triazole monomers  

NASA Technical Reports Server (NTRS)

The di(hydroxyphenyl)- 1,2,4-triazole monomers were first synthesized by reacting bis (4-hydroxyphenyl) hydrazide with aniline hydrochloride at 250 C in the melt and also by reacting 1,3 or 1,4-bis- (4-hydroxyphenyl)- phenylene- dihydrazide with 2 moles of aniline hydrochloride in the melt. Purification of the di(hydroxyphenyl)- 1,2,4-triazole monomers was accomplished by recrystallization. Poly (1,2,4-triazoles) (PT) were prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)- 1,2,4-triazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions were carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. This synthetic route has provided high molecular weight PT of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides.

Connell, John W. (inventor); Hergenrother, Paul M. (inventor); Wolf, Peter (inventor)

1993-01-01

155

DiGeorge syndrome with vertebral and rib dysplasia  

SciTech Connect

DiGeorge syndrome results from defect in the development of the third and fourth pharyngeal pouches, and is characterized by conotruncal heart defects, aplasia or hypoplasia of thymus and parathyroid glands resulting in immune deficiency and hypocalcemia. Other associated abnormalities include renal, thyroid and diaphragmatic defects, oral clefting, etc. Etiologically, it is heterogeneous, with a microdeletion of 22q11 present in over 80% of cases. Our patient was born following a pregnancy complicated by insulin dependent gestational diabetes. There was truncus arteriosus type 2, absense of thymic shadow on CXR with severe deficiency of T cell function, and persistent hypocalcemia with low parathormone. Right kidney was absent. Dysplastic ribs including fused and bifid ribs were noted. Hypoplastic vertebrae and hemivertebrae were present through thoracic and lumbar regions. Chromosome analysis was normal, and metaphase FISH analysis with probe N25 representing locus D22S75 did not show any deletion of 22q11.2. The skeletal findings similar to these have not been previously reported in association with DiGeorge syndrome to our knowledge. Vertebral and rib abnormalities are known to occur with pregestational maternal diabetes. Maternal diabetes has also been suggested to be a possible etiology in a very small proportion of DiGeorge syndrome cases. It is possible that these findings occured together on account of gestational maternal diabetes in our case.

Puno-Cocuzza, C.; David, K.; Kogekar, N. [Brooklyn Hospital Center, NY (United States)

1994-09-01

156

Cyclic di-GMP mediates Mycobacterium tuberculosis dormancy and pathogenecity.  

PubMed

Dormancy of Mycobacterium tuberculosis is likely to be a major cause of extended chemotherapeutic regimens and wide prevalence of tuberculosis. The molecular mechanisms underlying M. tuberculosis dormancy are not well understood. In this study, single-copy genes responsible for synthesis (dgc) and degradation (pde) of the ubiquitous bacterial second messenger, cyclic di-GMP (c-di-GMP), were deleted in the virulent M. tuberculosis strain H37Rv to generate dgc(mut) and ?pde, respectively. Under aerobic growth conditions, the two mutants and wild-type cells showed similar phenotypes. However, dgc(mut) and ?pde exhibited increased and reduced dormancy, respectively, in both anaerobiosis-triggered and vitamin C-triggered in vitro dormancy models, as determined by survival and growth recovery from dormancy. The transcriptomes of aerobic cultures of dgc(mut) and wild-type H37Rv exhibited no difference, whereas those of anaerobic cultures showed a significant difference with 61 genes that are not a part of the dosR regulon. Furthermore, ?pde but not dgc(mut) showed decreased infectivity with human THP-1 cells. ?pde also showed attenuated pathogenicity in a C57BL/6 mouse infection model. These findings are explained by c-di-GMP-mediated signaling negatively regulating M. tuberculosis dormancy and pathogenicity. PMID:24080120

Hong, Yuzhi; Zhou, Xiaodan; Fang, Haihong; Yu, Dan; Li, Chuanyou; Sun, Baolin

2013-11-01

157

Syntheses of Methyl 2,3-di-O-Glycyl-?-D-glucopyranoside and 4,6-di-O-Glycyl-2,3-di-O-methyl-?-D-glucopyranoside, and Removal of Aminoacyl Groups from Sugar Moieties  

Microsoft Academic Search

To confirm the potential usefulness of amino acid residues as protecting groups for sugar hydroxyls, methyl 2,3-di-O-glycyl-?-D-glucopyranoside (5) and methyl 4,6-di-O-glycyl-2,3-di-O-methyl-?-D-gluco-pyranoside (7) were synthesized as reference compounds. Conditions were then established for the removal of these aminoacyl groups from the sugar molecules. The reference compounds were easily prepared by condensation of methyl ?-D-glucopyranoside derivatives with N-protected glycine in the presence

Keisuke Kinomura; Masahiro Tamura; Tetsuo Oga; Hideo Okai

1984-01-01

158

Di e-Hellman Key Exchange Protocol, Its Generalization and Nilpotent Groups  

Microsoft Academic Search

Abstract: Author: Ayan MahalanobisTitle: Di#e-Hellman Key Exchange Protocol,its Generalization and Nilpotent GroupsDissertation Advisor: Dr. Spyros MagliverasDegree: Doctor of PhilosophyYear: 2005This dissertation has two chapters. In the first chapter we talk about the discrete logarithmproblem, more specifically we concentrate on the Di#e-Hellman key exchange protocol. We surveythe current state of security for the Di#e-Hellman key exchange protocol. We also motivate thereader

Ayan Mahalanobis

2005-01-01

159

Structural Basis of Ligand Binding by a C-di-GMP Riboswitch  

SciTech Connect

The second messenger signaling molecule bis-(3{prime}-5{prime})-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates many processes in bacteria, including motility, pathogenesis and biofilm formation. c-di-GMP-binding riboswitches are important downstream targets in this signaling pathway. Here we report the crystal structure, at 2.7 {angstrom} resolution, of a c-di-GMP riboswitch aptamer from Vibrio cholerae bound to c-di-GMP, showing that the ligand binds within a three-helix junction that involves base-pairing and extensive base-stacking. The symmetric c-di-GMP is recognized asymmetrically with respect to both the bases and the backbone. A mutant aptamer was engineered that preferentially binds the candidate signaling molecule c-di-AMP over c-di-GMP. Kinetic and structural data suggest that genetic regulation by the c-di-GMP riboswitch is kinetically controlled and that gene expression is modulated through the stabilization of a previously unidentified P1 helix, illustrating a direct mechanism for c-di-GMP signaling.

Smith, K.; Lipchock, S; Ames, T; Wang, J; Breaker, R; Strobel, S

2009-01-01

160

Occurrence of Cyclic di-GMP-Modulating Output Domains in Cyanobacteria: an Illuminating Perspective  

PubMed Central

ABSTRACT Microorganisms use a variety of metabolites to respond to external stimuli, including second messengers that amplify primary signals and elicit biochemical changes in a cell. Levels of the second messenger cyclic dimeric GMP (c-di-GMP) are regulated by a variety of environmental stimuli and play a critical role in regulating cellular processes such as biofilm formation and cellular motility. Cyclic di-GMP signaling systems have been largely characterized in pathogenic bacteria; however, proteins that can impact the synthesis or degradation of c-di-GMP are prominent in cyanobacterial species and yet remain largely underexplored. In cyanobacteria, many putative c-di-GMP synthesis or degradation domains are found in genes that also harbor light-responsive signal input domains, suggesting that light is an important signal for altering c-di-GMP homeostasis. Indeed, c-di-GMP-associated domains are often the second most common output domain in photoreceptors—outnumbered only by a histidine kinase output domain. Cyanobacteria differ from other bacteria regarding the number and types of photoreceptor domains associated with c-di-GMP domains. Due to the widespread distribution of c-di-GMP domains in cyanobacteria, we investigated the evolutionary origin of a subset of genes. Phylogenetic analyses showed that c-di-GMP signaling systems were present early in cyanobacteria and c-di-GMP genes were both vertically and horizontally inherited during their evolution. Finally, we compared intracellular levels of c-di-GMP in two cyanobacterial species under different light qualities, confirming that light is an important factor for regulating this second messenger in vivo.

Agostoni, Marco; Koestler, Benjamin J.; Waters, Christopher M.; Williams, Barry L.; Montgomery, Beronda L.

2013-01-01

161

Synthesis and study of conjugated polymers containing Di- or Triphenylamine  

SciTech Connect

This thesis consists of two separate parts. The first part addresses the synthesis and study of conjugated polymers containing di- or triphenylamine. Two types of polymers: linear polymers and dendrimers, were synthesized. The polymers were characterized by NMR, IR, UV, GPC, TGA and DSC. Electronic and optical properties of the polymers were studied through the conductivity measurements and excitation- emission spectra. the second part of this thesis deals with a reaction of electron-rich acetylenes with TCNE. The discovery of the reaction from charge transfer complex studies and the investigation of this reaction on various electron-rich acetylenes are presented.

Sukwattanasinitt, M.

1996-06-21

162

Synthesis of Di- and trivalent. beta. -aluminas by ion exchange  

SciTech Connect

Many of the mono- di-, and trivalent cations in the periodic chart diffuse rapidly in the ..beta..-alumina structure. ..beta..-Aluminas containing multivalent cations can be synthesized by ion exchange reactions starting with the sodium form of the compound. These facile reactions make it possible to prepare a wide variety of ..beta..-alumina compositions, many of which are metastable and inaccessible by normal synthetic means. This paper describes the methods used to synthesize multivalent ..beta..-aluminas and the preparation of a number of specific transition metal and lanthanide forms of these compounds.

Sattar, S.; Ghosal, B.; Underwood, M.L.; Mertwoy, H.; Saltzberg, M.A.; Frydrych, W.S.; Rohrer, G.S.; Farrington, G.C.

1986-11-15

163

Balsacones D-I, dihydrocinnamoyl flavans from Populus balsamifera buds.  

PubMed

A phytochemical investigation of an ethanolic extract from Populus balsamifera L. buds resulted in the isolation and characterization of twelve new flavan derivatives consisting of six pairs of enantiomers. Structures of (+) and (-)-balsacones D-I were elucidated based on spectroscopic data (1D and 2D NMR, MS) and their absolute configurations were established using X-ray single crystal diffraction analysis and ECD computational calculations. Antibacterial activity and cytotoxicity of all purified enantiomers were evaluated in vitro against Staphylococcus aureus and human skin fibroblast cells, respectively. PMID:24485585

Simard, François; Legault, Jean; Lavoie, Serge; Pichette, André

2014-04-01

164

Dichlorido(di-2-pyridylamine)mercury(II)  

PubMed Central

In the mol­ecule of the title compound, [HgCl2(C10H9N3)], the HgII atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from the chelating di-2-pyridylamine ligand and by two Cl atoms. In the crystal structure, inter­molecular N—H?Cl hydrogen bonds link the mol­ecules into centrosymmetric dimers. There is a ?–? contact between the pyridine rings [centroid–centroid distance = 3.896?(5)?Å].

Yousefi, Mohammad; Allahgholi Ghasri, Mohammad Reza; Heidari, Amene; Amani, Vahid

2009-01-01

165

Rapporti ISTISAN 11/29: L'agricoltura sociale come opportunia di sviluppo rurale sostenibile: prospecttive di applicazione nel campo della salute mentale. (Social Farming as an Opportunity for Sustainable Rural Development: Perspectives of Application in Mental Health).  

National Technical Information Service (NTIS)

On April 19th 2011 the Department of Cell Biology and Neurosciences of the Istituto Superiore di Sanita, in collaboration with the Istituto Nazionale di Economia Agraria, has organized the meeting 'Social farming as opportunity for sustainable rural devel...

A. Berry E. Alleva F. Circulli M. Borgi N. Francia

2011-01-01

166

Attivita e Impegno dell'Istituto Superiore di Sanita nella Lotta Control il Cancro. (Activities and Commitment of the Istituto Superiore di Sanita in the Fight Against Cancer).  

National Technical Information Service (NTIS)

Cancer is a global issue and a major public health problem, which profoundly affects both industrialized and developing countries. The Istituto Superiore di Sanita (ISS) (the Italian National Institute of Health) has developed over the years different and...

F. Belardelli F. Moretti

2012-01-01

167

Lotta alla Contraffazione Farmaceutica: Le Attivita Dell'Istituto Superiore di Sanita (Fight against Pharmacuetical Counterfeiting: The Activities of Istituto Superiore di Sanita).  

National Technical Information Service (NTIS)

Pharmaceutical counterfeiting is a serious public health problem concerning both developing and industrialized countries, but with different diffusion and characteristics. This report resumes the activities that the Istituto Superiore di Sanita (ISS, the ...

A. L. Rodomonte B. Gallinella E. Antoniella L. Fucili L. Manna L. Romanini L. Rufini L. Valvo M. Bartolomei M. DiGregorio M. Mirra M. G. Gaudiano N. Muleri P. Bertocchi S. Alimonti S. Lucattini

2010-01-01

168

Host Immune Response to Bacterial Cyclic Diguanylic Acid (c-di-GMP).  

National Technical Information Service (NTIS)

This work tested the hypothesis that c-di-GMP is a novel immunostimulatory molecule that modulates the immune response. Intramammary treatment of mice with c-di-GMP before S. aureus challenge gave a protective effect and a 1O,OOO-fold reduction in CFUs in...

D. K. Karaolis J. P. Nataro

2009-01-01

169

The cyclic-di-GMP signaling pathway in the Lyme disease spirochete, Borrelia burgdorferi  

PubMed Central

In nature, the Lyme disease spirochete Borrelia burgdorferi cycles between the unrelated environments of the Ixodes tick vector and mammalian host. In order to survive transmission between hosts, B. burgdorferi must be able to not only detect changes in its environment, but also rapidly and appropriately respond to these changes. One manner in which this obligate parasite regulates and adapts to its changing environment is through cyclic-di-GMP (c-di-GMP) signaling. c-di-GMP has been shown to be instrumental in orchestrating the adaptation of B. burgdorferi to the tick environment. B. burgdorferi possesses only one set of c-di-GMP-metabolizing genes (one diguanylate cyclase and two distinct phosphodiesterases) and one c-di-GMP-binding PilZ-domain protein designated as PlzA. While studies in the realm of c-di-GMP signaling in B. burgdorferi have exploded in the last few years, there are still many more questions than answers. Elucidation of the importance of c-di-GMP signaling to B. burgdorferi may lead to the identification of mechanisms that are critical for the survival of B. burgdorferi in the tick phase of the enzootic cycle as well as potentially delineate a role (if any) c-di-GMP may play in the transmission and virulence of B. burgdorferi during the enzootic cycle, thereby enabling the development of effective drugs for the prevention and/or treatment of Lyme disease.

Novak, Elizabeth A.; Sultan, Syed Z.; Motaleb, Md. A.

2014-01-01

170

New compatible solutes related to Di-myo-inositol-phosphate in members of the order Thermotogales.  

PubMed Central

The accumulation of intracellular organic solutes was examined in six species of the order Thermotogales by nuclear magnetic resonance spectroscopy. The newly discovered compounds di-2-O-beta-mannosyl-di-myo-inositol-1,1'(3,3')-phosphate and di-myo-inositol-1,3'-phosphate were identified in Thermotoga maritima and Thermotoga neapolitana. In the latter species, at the optimum temperature and salinity the organic solute pool was composed of di-myo-inositol-1,1'(3,3')-phosphate, beta-glutamate, and alpha-glutamate in addition to di-myo-inositol-1,3'-phosphate and di-2-O-beta-mannosyl-di-myo-inositol-1,1'(3,3')-phosphate. The concentrations of the last two solutes increased dramatically at supraoptimal growth temperatures, whereas beta-glutamate increased mainly in response to a salinity stress. Nevertheless, di-myo-inositol-1,1'(3,3')-phosphate was the major compatible solute at salinities above the optimum for growth. The amino acids alpha-glutamate and proline were identified under optimum growth conditions in Thermosipho africanus, and beta-mannosylglycerate, trehalose, and glycine betaine were detected in Petrotoga miotherma. Organic solutes were not detected, under optimum growth conditions, in Thermotoga thermarum and Fervidobacterium islandicum, which have a low salt requirement or none.

Martins, L O; Carreto, L S; Da Costa, M S; Santos, H

1996-01-01

171

Forma e funzioni delle reti di imprese: evidenze da una ricerca nel settore vitivinicolo  

Microsoft Academic Search

Il tema delle reti di imprese, già da tempo studiato, si presenta ora in tutta la sua rilevanza. La rete, infatti, costituisce uno strumento per incrementare la competitività delle imprese e per decretare il successo delle strategie da queste adottate. Il recente intervento che ha introdotto il contratto di rete testimonia anche il vivo interesse del legislatore. L’attuazione dello strumento

Federica Casarosa; Marco Gobbato

2010-01-01

172

Specializzazione delle strategie ed eterogeneitad i una popolazione di firm in un mercato finanziario  

Microsoft Academic Search

Nei sistemi complessi quali sono i mercati finanziari sono note da tempo le leggi che regolano le grandezze macroscopiche come i rendimenti o la volatilita di uno stock. Queste leggi hanno carattere universale e non dipen- dono dal particolare mercato o periodo considerati e sono note in letteratura come fatti stilizzati. Queste grandezze sono pero il risultato di una inter-

Gabriella Vaglica; Fabrizio Lillo

173

TiDi browser: a novel photo browsing technique for mobile devices  

Microsoft Academic Search

Today's digital photos can be tagged with information about when and where they were taken. On stationary computers, this information is often used to drive photo browsing. This is not the case for mobile devices. We describe first results of our current research on a novel photo browsing technique called TiDi Browser. TiDi Browser exploits time and location information available

Gerald Bieber; Christian Tominski; Bodo Urban

2007-01-01

174

Di usion without false rumors: on propagating updates in a Byzantine environment  

Microsoft Academic Search

We study how to e5ciently di use updates to a large distributed system of data replicas, some of which may exhibit arbitrary (Byzantine) failures. We assume that strictly fewer than t replicas fail, and that each update is initially received by at least t correct replicas. The goal is to di use each update to all correct replicas while ensuring

Dahlia Malkhi; Yishay Mansour; Michael K. Reiter

175

The cutaneous manifestations of atypical complete DiGeorge syndrome: a histopathologic and immunohistochemical study.  

PubMed

DiGeorge syndrome is a congenital anomaly with a constellation of findings that includes thymic hypoplasia. Only a small subset of patients with DiGeorge syndrome has complete athymia, classified as complete DiGeorge anomaly; one third of these patients show an eczematous dermatitis, oligoclonal T-cells and lymphadenopathy, known as atypical complete DiGeorge anomaly. Six biopsies from six patients with the distinctive clinical phenotype of atypical complete DiGeorge anomaly were studied. Every biopsy showed exocytosis (100%), parakeratosis, often confluent and spongiosis (100%). Neutrophilic abscesses (50%), dyskeratosis (67%) and satellite cell necrosis (50%) were seen. Perieccrine and perivascular inflammation were seen in half of the cases. Eosinophils were identified (83%); most commonly in both the epidermis and dermis. All of lymphocytes were CD3 positive. Most (83%) of cases contained T-cell intracellular antigen 1 (TIA-1) positive cells. Special testing of the selected patients using spectratyping identified oligoclonal T-cell populations. The presence of dyskeratotic keratinocytes, satellite cell necrosis and parakeratotic scale with neutrophils characterizes the cutaneous rash seen in this subset of complete DiGeorge syndrome patients. Such skin lesions from patients with DiGeorge anomaly should alert the pathologist to the potential diagnosis of atypical complete DiGeorge anomaly. The pathophysiologic role of the oligoclonal T-cells in this entity requires additional study. PMID:18333898

Selim, Maria Angelica; Markert, Mary L; Burchette, James L; Herman, Christopher M; Turner, John W

2008-04-01

176

Aspiration pneumonia in the child with DiGeorge syndrome -A case report-  

PubMed Central

DiGeorge syndrome is associated with a chromosome 22q11.2 deletion and manifests with variable clinical findings. Aspiration pneumonia can be a perioperative complication of great concern in this syndrome. In this report, we present a case of a 16-month old child with DiGeorge syndrome undergoing cranioplasty. He developed perioperative aspiration pneumonia but was managed successfully.

Han, Yun-Joung

2011-01-01

177

Evidence for Cyclic Di-GMP-Mediated Signaling in Bacillus subtilis  

PubMed Central

Cyclic di-GMP (c-di-GMP) is a second messenger that regulates diverse cellular processes in bacteria, including motility, biofilm formation, cell-cell signaling, and host colonization. Studies of c-di-GMP signaling have chiefly focused on Gram-negative bacteria. Here, we investigated c-di-GMP signaling in the Gram-positive bacterium Bacillus subtilis by constructing deletion mutations in genes predicted to be involved in the synthesis, breakdown, or response to the second messenger. We found that a putative c-di-GMP-degrading phosphodiesterase, YuxH, and a putative c-di-GMP receptor, YpfA, had strong influences on motility and that these effects depended on sequences similar to canonical EAL and RxxxR—D/NxSxxG motifs, respectively. Evidence indicates that YpfA inhibits motility by interacting with the flagellar motor protein MotA and that yuxH is under the negative control of the master regulator Spo0A?P. Based on these findings, we propose that YpfA inhibits motility in response to rising levels of c-di-GMP during entry into stationary phase due to the downregulation of yuxH by Spo0A?P. We also present evidence that YpfA has a mild influence on biofilm formation. In toto, our results demonstrate the existence of a functional c-di-GMP signaling system in B. subtilis that directly inhibits motility and directly or indirectly influences biofilm formation.

Chen, Yun; Chai, Yunrong

2012-01-01

178

Brucella melitensis Cyclic di-GMP Phosphodiesterase BpdA Controls Expression of Flagellar Genes?†  

PubMed Central

Brucella melitensis encounters a variety of conditions and stimuli during its life cycle—including environmental growth, intracellular infection, and extracellular dissemination—which necessitates flexibility of bacterial signaling to promote virulence. Cyclic-di-GMP is a bacterial secondary signaling molecule that plays an important role in adaptation to changing environments and altering virulence in a number of bacteria. To investigate the role of cyclic-di-GMP in B. melitensis, all 11 predicted cyclic-di-GMP-metabolizing proteins were separately deleted and the effect on virulence was determined. Three of these cyclic-di-GMP-metabolizing proteins were found to alter virulence. Deletion of the bpdA and bpdB genes resulted in attenuation of virulence of the bacterium, while deletion of the cgsB gene produced a hypervirulent strain. In a Vibrio reporter system to monitor apparent alteration in levels of cyclic-di-GMP, both BpdA and BpdB displayed a phenotype consistent with cyclic-di-GMP-specific phosphodiesterases, while CgsB displayed a cyclic-di-GMP synthase phenotype. Further analysis found that deletion of bpdA resulted in a dramatic decrease in flagellar promoter activities, and a flagellar mutant showed similar phenotypes to the bpdA and bpdB mutant strains in mouse models of infection. These data indicate a potential role for regulation of flagella in Brucella melitensis via cyclic-di-GMP.

Petersen, Erik; Chaudhuri, Pallab; Gourley, Chris; Harms, Jerome; Splitter, Gary

2011-01-01

179

Il quadro finanziario pluriennale dell'Unione e la costruzione del processo di integrazione europea  

Microsoft Academic Search

Il quadro finanziario pluriennale dell'Unione e la costruzione del processo di integrazione europea (di Silvano Presa) - ABSTRACT: This paper assesses how the eu budget is going to be shaped over the next decade in view of meeting the challenge of growth. Firstly, the paper briefly recalls the main features of the European Union’s public finances. Secondly, it highlights the

Silvano Presa

2005-01-01

180

LC/MS/MS-based quantitative assay for the secondary messenger molecule, c-di-GMP.  

PubMed

The secondary messenger molecule, 3',5'-cyclic diguanosine monophosphate (c-di-GMP), controls various cellular processes in bacteria. Direct measurement of intracellular concentration of c-di-GMP is fast becoming an important tool for studying prokaryotic biology. Here, we describe a comprehensive extraction protocol from live bacteria and quantitative analysis using LC/MS/MS. PMID:24818912

Irie, Yasuhiko; Parsek, Matthew R

2014-01-01

181

The cyclic-di-GMP signaling pathway in the Lyme disease spirochete, Borrelia burgdorferi.  

PubMed

In nature, the Lyme disease spirochete Borrelia burgdorferi cycles between the unrelated environments of the Ixodes tick vector and mammalian host. In order to survive transmission between hosts, B. burgdorferi must be able to not only detect changes in its environment, but also rapidly and appropriately respond to these changes. One manner in which this obligate parasite regulates and adapts to its changing environment is through cyclic-di-GMP (c-di-GMP) signaling. c-di-GMP has been shown to be instrumental in orchestrating the adaptation of B. burgdorferi to the tick environment. B. burgdorferi possesses only one set of c-di-GMP-metabolizing genes (one diguanylate cyclase and two distinct phosphodiesterases) and one c-di-GMP-binding PilZ-domain protein designated as PlzA. While studies in the realm of c-di-GMP signaling in B. burgdorferi have exploded in the last few years, there are still many more questions than answers. Elucidation of the importance of c-di-GMP signaling to B. burgdorferi may lead to the identification of mechanisms that are critical for the survival of B. burgdorferi in the tick phase of the enzootic cycle as well as potentially delineate a role (if any) c-di-GMP may play in the transmission and virulence of B. burgdorferi during the enzootic cycle, thereby enabling the development of effective drugs for the prevention and/or treatment of Lyme disease. PMID:24822172

Novak, Elizabeth A; Sultan, Syed Z; Motaleb, Md A

2014-01-01

182

77 FR 18752 - Benzidine-Based Chemical Substances; Di-n  

Federal Register 2010, 2011, 2012, 2013

...Chemical Substances; Di-n-pentyl phthalate (DnPP); and Alkanes, C[ihel1...substances; a SNUR for di-n-pentyl phthalate (DnPP) (1,2-benzenedicarboxylic...CAS No. 131-18-0, an ortho-phthalate (or phthalate ester). B. What...

2012-03-28

183

MAgentA: Un Sistema Multi Agente per la Gestione di Agende e Riunioni  

Microsoft Academic Search

In questo articolo viene presentato MAgentA, un sistema multi-agente sviluppato nel contesto del progetto interu- niversitario ANEMONE allo scopo di gestire agende e pianificare riunioni tra gli utenti in modo semiautomatico. Ogni agenda è gestita da un agente che conosce gli impegni personali e le preferenze di un particolare utente, mentre le riunioni vengono organizzate da un apposito agente in

Pietro Baroni; Alfonso Gerevini; Paolo Toninelli

2005-01-01

184

Variabilità interannuale del fi toplancton del Lago di Tovel (Trentino, Italia)  

Microsoft Academic Search

RIASSUNTO - Variabilità interannuale del fi toplancton del Lago di Tovel (Trentino, Italia) - Lo studio del fi toplancton del Lago di Tovel nel periodo 2002-2004 ha avuto come principali obiettivi l'analisi della variabilità interannuale delle dinamiche stagionali nel Bacino Principale e nella Baia Rossa, il confronto tra le associazioni fi toplanctoniche attuali e passate (prima e dopo la scomparsa

Monica TOLOTTI; Dámaso CALLIARI; Flavio CORRADINI

185

A Basic Behavior of CNG DI Combustion in a Spark-Ignited Rapid Compression Machine  

Microsoft Academic Search

A basic characteristics of compressed natural gas direct-injection (CNG DI) combustion was studied by using a rapid compression machine. Results show that comparing with homogeneous mixture, CNG DI has short combustion duration, high pressure rise due to combustion, and high rate of heat release, which are considered to come from the charge stratification and the gas flow generated by the

Zuohua Huang; Seiichi Shiga; Takamasa Ueda; Nobuhisa Jingu; Hisao Nakamura; Tsuneaki Ishima; Tomio Obokata; Mitsuhiro Tsue; Michikata Kono

2002-01-01

186

A Descriptive Grammar of Sa'i:di Egyptian Colloquial Arabic. Janua Linguarum Series Practica 32.  

ERIC Educational Resources Information Center

This study presents the first descriptive analysis of the structure of Sa'i:di, the variety of Egyptian Arabic spoken by the inhabitants of the Nile Valley between Cairo and Aswan. It is hoped that this study, designed to describe the phonemics, morphemics, and syntax of Sa'i:di, will contribute to dialect studies of the varieties of Arabic spoken…

Khalafallah, Abdelghany A.

187

Crenoidrokinesiterapia e supplementazione di vit. D3: un efficace binomio per ridurre il rischio di caduta in donne osteoporotiche con ipovitaminosi d3  

Microsoft Academic Search

Introduzione L'osteoporosi è una patologia comune nelle donne dopo la menopausa e in età senile. È caratterizzata da fragilità dello schele- tro, ridotta densità minerale ossea e alta morbilità. Secondo un rap- porto fornito dall'Organizzazione Mondiale della Sanità (OMS), l'o- steoporosi è una patologia che colpisce più di 75 milioni di persone negli Stati Uniti d'America, in Giappone e in

D. M. CARLUCCI; G. ZANARDI; P. CHIODERA; V. COIRO

188

Trattamento fisioterapico secondo le linee guida KNGF vs trattamento motorio di ginnastica dolce in pazienti affetti da malattia di Parkinson (MP): studio randomizzato e controllato  

Microsoft Academic Search

Introduzione La malattia di Parkinson (MP) è una patologia degenerativa del sistema nervoso centrale (SNC) e costituisce una delle più frequenti malattie neurologiche dell'età medio-avanzata: nei paesi industrializ- zati la prevalenza nella popolazione superiore a 60 anni è dell'1%1. La perdita dei neuroni dopaminergici della pars compacta della sostanza nera, con gliosi e presenza di inclusioni eosinofile citopla- smatiche (corpi

S. DIPASQUALE; I. MESSINEO; C. CERRI; F. SASANELLI; V. FETONI

189

PENGEMBANGAN E-GOVERNMENT UNTUK PENINGKATAN TRANSPARANSI PELAYANAN PUBLIK Studi Kasus UPIK di Pemkot Jogjakarta dan E-Procurement di Pemkot Surabaya  

Microsoft Academic Search

Berbeda dengan penerapan teknologi informasi di kebanyakan organisasi swasta yang sudah menggunakan konsep e-commerce secara ekstensif, penerapan konsep e-government dalam organisasi publik di Indonesia masih tertinggal. Kendala yang dihadapi dalam organisasi publik bukan semata-mata ketersediaan teknologi atau dana, tetapi juga menyangkut berbagai persoalan politis dan manajerial yang sangat banyak dan memerlukan upaya pemecahan masalah yang begitu kompleks. Komitmen pimpinan organisasi

Wahyudi Kumorotomo

190

Urinary and amniotic fluid levels of phthalate monoesters in rats after the oral administration of di(2-ethylhexyl) phthalate and di- n-butyl phthalate  

Microsoft Academic Search

Two studies were designed to examine amniotic fluid and maternal urine concentrations of the di(2-ethylhexyl) phthalate (DEHP) metabolite mono(2-ethylhexyl) phthalate (MEHP) and the di-n-butyl phthalate (DBP) metabolite monobutyl phthalate (MBP) after administration of DEHP and DBP during pregnancy. In the first study, pregnant Sprague–Dawley rats were administered 0, 11, 33, 100, or 300mg DEHP\\/kg\\/day by oral gavage starting on gestational

Antonia M. Calafat; John W. Brock; Manori J. Silva; L. Earl Gray; John A. Reidy; Dana B. Barr; Larry L. Needham

2006-01-01

191

Critical cleaning agents for Di-2-ethylhexyl sebacate.  

SciTech Connect

It is required that Di-2-ethylhexyl Sebacate oil, also commonly known as Dioctyl Sebacate oil, be thoroughly removed from certain metals, in this case stainless steel parts with narrow, enclosed spaces. Dioctyl Sebacate oil is a synthetic oil with a low compressibility. As such, it is ideally used for high pressure calibrations. The current method to remove the Dioctyl Sebacate from stainless steel parts with narrow, enclosed spaces is a labor-intensive, multi-step process, including a detergent clean, a deionized (DI) water rinse, and several solvent rinses, to achieve a nonvolatile residue of0.04 mg per 50 mL rinse effluent. This study was undertaken to determine a superior detergent/solvent cleaning method for the oil to reduce cleaning time and/or the amount of detergent/solvent used. It was determined that while some detergent clean the oil off the metal better than the current procedure, using only solvents obtained the best result. In addition, it can be inferred, based on elevated temperature test results, that raising the temperature of the oil-contaminated stainless steel parts to approximately 50%C2%B0C will provide for improved cleaning efficacy.

Hartley, Mya; Archuleta, Kim M.

2013-08-01

192

OSSERVAZIONE CON TECNICA E.S.P.I. DEL COMPORTAMENTO A COMPRESSIONE DI MATERIALI QUASI-FRAGILI  

Microsoft Academic Search

Oggetto di questo lavoro è il perfezionamento di una tecnica interferometrica a luce laser E.S.P.I. per lo studio del comportamento a compressione di materiali quasi-fragili. Per lo sviluppo del sistema E.S.P.I. sono state effettuate prove di compressione su campioni prismatici in gasbeton, un particolare conglomerato aerato. Per misurare gli spostamenti verticali della superficie dei campioni, il setup E.S.P.I. è stato

Eva Coïsson; Daniele Ferretti

193

An Artificial Intelligence Approach to Industrial Design Support Un Approccio di Intelligenza Artificiale a Sostegno del Disegno Industriale  

Microsoft Academic Search

Il processo di Disegno Industriale si estende dalle analisi di mercato, dalla concettualizzazione, dalla generazione della forma alla formulazione di previsioni, all'ana- lisi ingegneristica, all'analisi dell'utente ecc. Questo richiede un ampio raggio di conoscen- za del design, e delle tecniche provenienti da discipline diverse. Il supporto al disegno in- dustriale basato sul computer è limitato perchè la maggioranza dei sistemi

Ming Xi Tang

194

Riboswitches in eubacteria sense the second messenger c-di-AMP  

PubMed Central

Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered bacterial second messenger implicated in the control of cell wall metabolism, osmotic stress responses, and sporulation. However, the mechanisms by which c-di-AMP triggers these physiological responses have remained largely unknown. Intriguingly, a candidate riboswitch class called ydaO associates with numerous genes involved in these same processes. Although a representative ydaO motif RNA recently was reported to weakly bind ATP, we report that numerous members of this noncoding RNA class selectively respond to c-di-AMP with sub-nanomolar affinity. Our findings resolve the mystery regarding the primary ligand for this extremely common riboswitch class and expose a major portion of the super-regulon of genes that are controlled by the widespread bacterial second messenger c-di-AMP.

Nelson, James W.; Sudarsan, Narasimhan; Furukawa, Kazuhiro; Weinberg, Zasha; Wang, Joy X.; Breaker, Ronald R.

2013-01-01

195

Disintegration of aerobic granules: role of second messenger cyclic di-GMP.  

PubMed

Loss of structural stability of aerobic granular process is the challenge for its field applications to treat wastewaters. The second messenger, cyclic diguanylate (c-di-GMP), is widely used by bacteria to regulate the synthesis of exopolysaccharide. This study for the first time confirmed the correlation between concentration of intracellular c-di-GMP and the granular stability under sequencing batch reactor (MBR) mode. In the presence of manganese ions (Mn(2+)), the concentrations of intracellular c-di-GMP and of extracellular polysaccharides and proteins in granules were declined. Clone library study revealed that the polysaccharide producers. Acinetobacter sp., Thauera sp., Bdellovibrio sp. and Paracoccus sp. were lost after Mn(2+) addition. The findings reported herein confirmed that the c-di-GMP is a key chemical factor epistatic to quorum sensing to determine granular stability. Stimulation of synthesis of intracellular c-di-GMP presents a potential way to enhance long-term stability of aerobic granules. PMID:23948271

Wan, Chunli; Zhang, Peng; Lee, Duu-Jong; Yang, Xue; Liu, Xiang; Sun, Supu; Pan, Xiangliang

2013-10-01

196

A Tangled Web: Regulatory Connections between Quorum Sensing and Cyclic Di-GMP  

PubMed Central

Bacteria sense and respond to environmental cues to control important developmental processes. Two widely conserved and important strategies that bacteria employ to sense changes in population density and local environmental conditions are quorum sensing (QS) and cyclic di-GMP (c-di-GMP) signaling, respectively. The importance of these pathways in controlling a broad variety of functions, including virulence, biofilm formation, and motility, has been recognized in many species. Recent research has shown that these pathways are intricately intertwined. Here we review the regulatory connections between QS and c-di-GMP signaling. We propose that the integration of QS with c-di-GMP allows bacteria to assimilate information about the local bacterial population density with other physicochemical environmental signals within the broader c-di-GMP signaling network.

Srivastava, Disha

2012-01-01

197

Interactions of the c-di-GMP riboswitch with its second messenger ligand  

PubMed Central

The c-di-GMP riboswitch is a macromolecular target in the c-di-GMP second messenger signaling pathway. It regulates many genes related to c-di-GMP metabolism as well as genes involved in bacterial motility, virulence and biofilm formation. The riboswitch makes asymmetric contacts to the bases and phosphate backbone of this symmetric dinucleotide. The phylogenetics suggested and mutagenesis has confirmed that this is a flexible motif where variants can make alternative interactions with each of the guanine bases of c-di-GMP. A mutant riboswitch has been designed that can bind a related molecule, c-di-AMP, confirming the most important contacts made to the ligand. The binding kinetics reveal that this is a kinetically controlled riboswitch and mutations to the riboswitch lead to increases in the off-rate. This riboswitch is therefore flexible in sequence as well as kinetic properties.

Smith, Kathryn D.; Strobel, Scott A.

2013-01-01

198

Di-alkylated paromomycin derivatives: targeting the membranes of gram positive pathogens that cause skin infections.  

PubMed

A collection of paromomycin-based di-alkylated cationic amphiphiles differing in the lengths of their aliphatic chain residues were designed, synthesized, and evaluated against 14 Gram positive pathogens that are known to cause skin infections. Paromomycin derivatives that were di-alkylated with C7 and C8 linear aliphatic chains had improved antimicrobial activities relative to the parent aminoglycoside as well as to the clinically used membrane-targeting antibiotic gramicidin D; several novel derivatives were at least 16-fold more potent than the parent aminoglycoside paromomycin. Comparison between a di-alkylated and a mono-alkylated paromomycin indicated that the di-alkylation strategy leads to both an improvement in antimicrobial activity and to a dramatic reduction in undesired red blood cell hemolysis caused by many aminoglycoside-based cationic amphiphiles. Scanning electron microscopy provided evidence for cell surface damage by the reported di-alkylated paromomycins. PMID:23602621

Berkov-Zrihen, Yifat; Herzog, Ido M; Feldman, Mark; Sonn-Segev, Adar; Roichman, Yael; Fridman, Micha

2013-06-15

199

Coordinated cyclic-di-GMP repression of Salmonella motility through YcgR and cellulose.  

PubMed

Cyclic di-GMP (c-di-GMP) is a secondary messenger that controls a variety of cellular processes, including the switch between a biofilm and a planktonic bacterial lifestyle. This nucleotide binds to cellular effectors in order to exert its regulatory functions. In Salmonella, two proteins, BcsA and YcgR, both of them containing a c-di-GMP binding PilZ domain, are the only known c-di-GMP receptors. BcsA, upon c-di-GMP binding, synthesizes cellulose, the main exopolysaccharide of the biofilm matrix. YcgR is dedicated to c-di-GMP-dependent inhibition of motility through its interaction with flagellar motor proteins. However, previous evidences indicate that in the absence of YcgR, there is still an additional element that mediates motility impairment under high c-di-GMP levels. Here we have uncovered that cellulose per se is the factor that further promotes inhibition of bacterial motility once high c-di-GMP contents drive the activation of a sessile lifestyle. Inactivation of different genes of the bcsABZC operon, mutation of the conserved residues in the RxxxR motif of the BcsA PilZ domain, or degradation of the cellulose produced by BcsA rescued the motility defect of ?ycgR strains in which high c-di-GMP levels were reached through the overexpression of diguanylate cyclases. High c-di-GMP levels provoked cellulose accumulation around cells that impeded flagellar rotation, probably by means of steric hindrance, without affecting flagellum gene expression, exportation, or assembly. Our results highlight the relevance of cellulose in Salmonella lifestyle switching as an architectural element that is both essential for biofilm development and required, in collaboration with YcgR, for complete motility inhibition. PMID:23161026

Zorraquino, Violeta; García, Begoña; Latasa, Cristina; Echeverz, Maite; Toledo-Arana, Alejandro; Valle, Jaione; Lasa, Iñigo; Solano, Cristina

2013-02-01

200

Responses to elevated c-di-GMP levels in mutualistic and pathogenic plant-interacting bacteria.  

PubMed

Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

Pérez-Mendoza, Daniel; Aragón, Isabel M; Prada-Ramírez, Harold A; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

2014-01-01

201

Cyclic Di-GMP modulates the disease progression of Erwinia amylovora.  

PubMed

The second messenger cyclic di-GMP (c-di-GMP) is a nearly ubiquitous intracellular signal molecule known to regulate various cellular processes, including biofilm formation, motility, and virulence. The intracellular concentration of c-di-GMP is inversely governed by diguanylate cyclase (DGC) enzymes and phosphodiesterase (PDE) enzymes, which synthesize and degrade c-di-GMP, respectively. The role of c-di-GMP in the plant pathogen and causal agent of fire blight disease Erwinia amylovora has not been studied previously. Here we demonstrate that three of the five predicted DGC genes in E. amylovora (edc genes, for Erwinia diguanylate cyclase), edcA, edcC, and edcE, are active diguanylate cyclases. We show that c-di-GMP positively regulates the secretion of the main exopolysaccharide in E. amylovora, amylovoran, leading to increased biofilm formation, and negatively regulates flagellar swimming motility. Although amylovoran secretion and biofilm formation are important for the colonization of plant xylem tissues and the development of systemic infections, deletion of the two biofilm-promoting DGCs increased tissue necrosis in an immature-pear infection assay and an apple shoot infection model, suggesting that c-di-GMP negatively regulates virulence. In addition, c-di-GMP inhibited the expression of hrpA, a gene encoding the major structural component of the type III secretion pilus. Our results are the first to describe a role for c-di-GMP in E. amylovora and suggest that downregulation of motility and type III secretion by c-di-GMP during infection plays a key role in the coordination of pathogenesis. PMID:23475975

Edmunds, Adam C; Castiblanco, Luisa F; Sundin, George W; Waters, Christopher M

2013-05-01

202

Cyclic Di-GMP Modulates the Disease Progression of Erwinia amylovora  

PubMed Central

The second messenger cyclic di-GMP (c-di-GMP) is a nearly ubiquitous intracellular signal molecule known to regulate various cellular processes, including biofilm formation, motility, and virulence. The intracellular concentration of c-di-GMP is inversely governed by diguanylate cyclase (DGC) enzymes and phosphodiesterase (PDE) enzymes, which synthesize and degrade c-di-GMP, respectively. The role of c-di-GMP in the plant pathogen and causal agent of fire blight disease Erwinia amylovora has not been studied previously. Here we demonstrate that three of the five predicted DGC genes in E. amylovora (edc genes, for Erwinia diguanylate cyclase), edcA, edcC, and edcE, are active diguanylate cyclases. We show that c-di-GMP positively regulates the secretion of the main exopolysaccharide in E. amylovora, amylovoran, leading to increased biofilm formation, and negatively regulates flagellar swimming motility. Although amylovoran secretion and biofilm formation are important for the colonization of plant xylem tissues and the development of systemic infections, deletion of the two biofilm-promoting DGCs increased tissue necrosis in an immature-pear infection assay and an apple shoot infection model, suggesting that c-di-GMP negatively regulates virulence. In addition, c-di-GMP inhibited the expression of hrpA, a gene encoding the major structural component of the type III secretion pilus. Our results are the first to describe a role for c-di-GMP in E. amylovora and suggest that downregulation of motility and type III secretion by c-di-GMP during infection plays a key role in the coordination of pathogenesis.

Edmunds, Adam C.; Castiblanco, Luisa F.; Sundin, George W.

2013-01-01

203

Enhanced healing of full-thickness burn wounds using di-rhamnolipid  

PubMed Central

The aim of this study was to investigate the properties of di-rhamnolipid [?-L-rhamnopyranosyl-(1–2)-?-L-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoic acid, also referred to as di-rhamnolipid BAC-3] relating to the process of cutaneous wound healing. Di-rhamnolipid was prepared in a eucerin ointment and applied topically on full-thickness burn wounds in normal Sprague–Dawley rats covering 5% of the total body surface area. The rate of wound closure was measured over the period of 45 days. The collagen content was evaluated microscopically, by performing densitometric analysis on Verhoeff’s stained histopathological slides of wound biopsies taken at the end of 45th day of di-rhamnolipid treatment. Di-rhamnolipid toxicity was assessed with the subcutaneous multi-dose study in Swiss–Webster mice. The treatment of full-thickness-burn wounds with topical 0.1% di-rhamnolipid accelerated the closure of wounds on day 21 of the treatment by 32% compared to the control ( p < 0.05). On day 35, the wounds closed in all animals-treated with 0.1% di-rhamnolipid ointment while some rats in the control group had open wounds on days 35 and even 45. Histologic comparisons have shown that di-rhamnolipid significantly decreased collagen content in burn wounds (47.5%, p < 0.05) as compared to the vehicle-treated (control) wounds. Di-rhamnolipid was well-tolerated. The results of this study raise the possibility of potential efficacy of di-rhamnolipid in accelerating normal wound healing and perhaps in overcoming defects associated with healing failure in chronic wounds.

Stipcevic, Tamara; Piljac, Ante; Piljac, Goran

2006-01-01

204

Coordinated Cyclic-Di-GMP Repression of Salmonella Motility through YcgR and Cellulose  

PubMed Central

Cyclic di-GMP (c-di-GMP) is a secondary messenger that controls a variety of cellular processes, including the switch between a biofilm and a planktonic bacterial lifestyle. This nucleotide binds to cellular effectors in order to exert its regulatory functions. In Salmonella, two proteins, BcsA and YcgR, both of them containing a c-di-GMP binding PilZ domain, are the only known c-di-GMP receptors. BcsA, upon c-di-GMP binding, synthesizes cellulose, the main exopolysaccharide of the biofilm matrix. YcgR is dedicated to c-di-GMP-dependent inhibition of motility through its interaction with flagellar motor proteins. However, previous evidences indicate that in the absence of YcgR, there is still an additional element that mediates motility impairment under high c-di-GMP levels. Here we have uncovered that cellulose per se is the factor that further promotes inhibition of bacterial motility once high c-di-GMP contents drive the activation of a sessile lifestyle. Inactivation of different genes of the bcsABZC operon, mutation of the conserved residues in the RxxxR motif of the BcsA PilZ domain, or degradation of the cellulose produced by BcsA rescued the motility defect of ?ycgR strains in which high c-di-GMP levels were reached through the overexpression of diguanylate cyclases. High c-di-GMP levels provoked cellulose accumulation around cells that impeded flagellar rotation, probably by means of steric hindrance, without affecting flagellum gene expression, exportation, or assembly. Our results highlight the relevance of cellulose in Salmonella lifestyle switching as an architectural element that is both essential for biofilm development and required, in collaboration with YcgR, for complete motility inhibition.

Zorraquino, Violeta; Garcia, Begona; Latasa, Cristina; Echeverz, Maite; Toledo-Arana, Alejandro; Valle, Jaione

2013-01-01

205

Cyclic di-GMP: the First 25 Years of a Universal Bacterial Second Messenger  

PubMed Central

SUMMARY Twenty-five years have passed since the discovery of cyclic dimeric (3??5?) GMP (cyclic di-GMP or c-di-GMP). From the relative obscurity of an allosteric activator of a bacterial cellulose synthase, c-di-GMP has emerged as one of the most common and important bacterial second messengers. Cyclic di-GMP has been shown to regulate biofilm formation, motility, virulence, the cell cycle, differentiation, and other processes. Most c-di-GMP-dependent signaling pathways control the ability of bacteria to interact with abiotic surfaces or with other bacterial and eukaryotic cells. Cyclic di-GMP plays key roles in lifestyle changes of many bacteria, including transition from the motile to the sessile state, which aids in the establishment of multicellular biofilm communities, and from the virulent state in acute infections to the less virulent but more resilient state characteristic of chronic infectious diseases. From a practical standpoint, modulating c-di-GMP signaling pathways in bacteria could represent a new way of controlling formation and dispersal of biofilms in medical and industrial settings. Cyclic di-GMP participates in interkingdom signaling. It is recognized by mammalian immune systems as a uniquely bacterial molecule and therefore is considered a promising vaccine adjuvant. The purpose of this review is not to overview the whole body of data in the burgeoning field of c-di-GMP-dependent signaling. Instead, we provide a historic perspective on the development of the field, emphasize common trends, and illustrate them with the best available examples. We also identify unresolved questions and highlight new directions in c-di-GMP research that will give us a deeper understanding of this truly universal bacterial second messenger.

Galperin, Michael Y.; Gomelsky, Mark

2013-01-01

206

Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria  

PubMed Central

Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels.

Perez-Mendoza, Daniel; Aragon, Isabel M.; Prada-Ramirez, Harold A.; Romero-Jimenez, Lorena; Ramos, Cayo; Gallegos, Maria-Trinidad; Sanjuan, Juan

2014-01-01

207

Cyclic di-GMP: the first 25 years of a universal bacterial second messenger.  

PubMed

Twenty-five years have passed since the discovery of cyclic dimeric (3'?5') GMP (cyclic di-GMP or c-di-GMP). From the relative obscurity of an allosteric activator of a bacterial cellulose synthase, c-di-GMP has emerged as one of the most common and important bacterial second messengers. Cyclic di-GMP has been shown to regulate biofilm formation, motility, virulence, the cell cycle, differentiation, and other processes. Most c-di-GMP-dependent signaling pathways control the ability of bacteria to interact with abiotic surfaces or with other bacterial and eukaryotic cells. Cyclic di-GMP plays key roles in lifestyle changes of many bacteria, including transition from the motile to the sessile state, which aids in the establishment of multicellular biofilm communities, and from the virulent state in acute infections to the less virulent but more resilient state characteristic of chronic infectious diseases. From a practical standpoint, modulating c-di-GMP signaling pathways in bacteria could represent a new way of controlling formation and dispersal of biofilms in medical and industrial settings. Cyclic di-GMP participates in interkingdom signaling. It is recognized by mammalian immune systems as a uniquely bacterial molecule and therefore is considered a promising vaccine adjuvant. The purpose of this review is not to overview the whole body of data in the burgeoning field of c-di-GMP-dependent signaling. Instead, we provide a historic perspective on the development of the field, emphasize common trends, and illustrate them with the best available examples. We also identify unresolved questions and highlight new directions in c-di-GMP research that will give us a deeper understanding of this truly universal bacterial second messenger. PMID:23471616

Römling, Ute; Galperin, Michael Y; Gomelsky, Mark

2013-03-01

208

The e ects of di usion mechanism and void structure on transport rates and tortuosity factors in complex porous structures  

Microsoft Academic Search

Tracer di usion simulations within random porous structures show that tortuosity factors are independent of di usion mechanism for all practical void fractions when an equivalent Knudsen di usivity is correctly de6ned. Previous studies concluded that tortuosity factors, a geometric property of the void space as de6ned, increase with increasing Knudsen number, Kn, a measure of the relative number of

M. Zalc

2004-01-01

209

N-[(2,6-Di-ethyl-phen-yl)carbamo-thio-yl]-2,2-di-phenyl-acetamide  

PubMed Central

In the title compound, C25H26N2OS, the diethyl-substituted benzene ring forms dihedral angles of 67.38?(9) and 55.32?(9)° with the terminal benzene rings. The mol­ecule adopts a trans–cis conformation with respect to the orientations of the di­phenyl­methane and 1,3-di­ethyl­benzene groups with respect to the S atom across the C—N bonds. This conformation is stabilized by an intra­molecular N—H?O hydrogen bond, which generates an S(6) ring. In the crystal, pairs of N—H?S hydrogen bonds link the mol­ecules into inversion dimers, forming R 2 2(6) loops. The dimer linkage is reinforced by a pair of C—H?S hydrogen bonds, which generate R 2 2(8) loops. Weak C—H?? and ?–? [centroid–centroid seperation = 3.8821?(10)?Å] inter­actions also occur in the crystal structure.

Yusof, Mohd Sukeri Mohd; Razali, Nur Rafikah; Arshad, Suhana; Rahman, Azhar Abdul; Razak, Ibrahim Abdul

2013-01-01

210

Chronic toxicity of di-n-butyl and di-n-octyl phthalate to Daphnia magna and the fathead minnow  

SciTech Connect

The toxicities of di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) were assessed by measuring the effect of exposure to these compounds on the fecundity of Daphnia magna and on the hatching and survival of the early life stages of the fathead minnow Pimephales promelas. For D. magna, exposure to 1.8 mg/L DBP or 1.0 mg/L DOP caused a significant reduction in reproduction. Doses of 0.56 mg/L DBP or 0.32 mg/L DOP had no significant effect in decreasing reproduction. Survival of fathead minnow embryos was decreased by exposure to 1.8 mg/L DBP; none of the embryos exposed to this dose hatched successfully. Hatching and larval survival were affected by exposure to 1.0 mg/L DBP, but not to 0.56 mg/L. Exposure to DOP did not affect survival of either early embryos or larvae of the fathead minnow at doses up to 10 mg/L (the highest dose tested). Hatching of the embryos was significantly decreased at 10 mg/L, but not at 3.2 mg/L DOP. 26 references, 4 figures, 11 tables.

McCarthy, J.F.; Whitmore, D.K.

1985-01-01

211

A new adjuvant delivery system 'cyclic di-GMP/YSK05 liposome' for cancer immunotherapy.  

PubMed

Cyclic dinucleotides are of importance in the field of microbiology and immunology. They function as second messengers and are thought to participate in the signal transduction of cytosolic DNA immune responses. One such dinucleotide, cyclic di-GMP (c-di-GMP), stimulates the immune system. It is thought that c-di-GMP is recognized by ATP dependent RNA helicase (DDX41) in the cytosol, forms a complex with the Stimulator of interferon genes protein (STING), triggers a signal via the tank binding kinase 1-interferon regulatory factor 3 (TBK1-IRF3) pathway and induces the production of type I interferons. Therefore c-di-GMP can be thought of as a new class of adjuvant. However, because c-di-GMP contains two phosphate groups, this prevents its use as an adjuvant because it cannot pass through the cell membrane, even though the target molecule of c-di-GMP is located in the cytoplasm. Our group has been developing a series of liposomal drug delivery systems and recently investigated YSK05 which is a synthetic, pH sensitive lipid that has a high fusogenicity. We utilized this lipid as a carrier to transport c-di-GMP into the cytosol to then use c-di-GMP as an adjuvant. Based on screening experiments, YSK05/POPE/cholesterol=40/25/35 was found to induce IFN-? in Raw264.7 cells. The induction of IFN-? from c-di-GMP liposomes was inhibited by adding BX795, a TBK1 inhibitor, indicating that the production of IFN-? caused the activation of the STING-TBK1 pathway. C-di-GMP liposomes also showed significantly higher levels of expression of CD80, CD86 and MHC class I. The c-di-GMP/YSK05 liposome facilitated antigen specific cytotoxic T cell activity and the inhibition of tumor growth in a mouse model. These findings indicate that c-di-GMP/YSK05 liposomes could be used, not only to transfer c-di-GMP to the cytosol and induce an innate immune system but also as a platform for investigating the mechanism of immune sensing with cyclic dinucleotides in vitro and in vivo. PMID:24727060

Miyabe, Hiroko; Hyodo, Mamoru; Nakamura, Takashi; Sato, Yusuke; Hayakawa, Yoshihiro; Harashima, Hideyoshi

2014-06-28

212

Diffusion boriding of a press tool of DI22 steel  

SciTech Connect

For the purpose of increasing the quality and thickness uniformity of the borided case on parts of complex configuration they used a method of boriding in a molten active low-melting transport metal making it possible to combine diffusion impregnation with subsequent heat treatment. The transport metal was lithium. The final purpose of this investigation was the development of a method of hardening coatings for press tools of DI22 (4Kh4VMFS) steel with (%) 0.37-0.44 C, 0.2-0.5 Mn, 3.2-4.0 Cr, 0.8-1.2 W, 0.6-0.9 V, 1.2-1.5 Mo, and 0.6-1.0 Si.

Duryagina, Z.A.; Pastukhova, L.V.; Kitsak, M.I.

1987-11-01

213

Molecular Structure of Di-t-butyl-peroxide  

NSDL National Science Digital Library

Di-tert-Butyl Peroxide is used as a polymerization initiator, curing agent and cross-linking agent. It is a highly reactive compound, which can be flammable when exposed to open flames and sparks. Upon exposure to heat, it undergoes gaseous decomposition. Its vapors are denser than air, hence it travels along the ground. It should be kept away from combustible material like wood, clothing, oil, and paper. This material may form flammable dust-air mixtures. Potential for a dust explosion may exist. Exposure to humans is mainly through inhalation, dermal contact. It can cause irritation to eye and skin, inhalation can cause cough, shortness of breath and sore throat, and ingestion can cause vomiting and abdominal cramps.

2002-09-27

214

dEs and the dI fundamental plane  

NASA Astrophysics Data System (ADS)

Despite much work, the connection between dwarf elliptical galaxies (dEs) and dwarf irregulars (dIs) remains unclear. Recently, we found that the surface brightness profiles (SBPs) of dIs in the near-infrared can be well fitted with a hyperbolic secant (sech) function. From sech fits, a tight relationship was derived between the absolute magnitude, central surface brightness, and 21cm line widths, which amounts to a fundamental plane for dIs. Here we examine how closely dEs fit into the dI fundamental plane using published data for 22 dEs in the Virgo cluster and the Local Group. Over a 9 mag interval in absolute magnitude the dEs fall in the plane defined by the dIs. The outstanding overlap suggests more than a casual relationship between the two classes.

Vaduvescu, Ovidiu; McCall, Marshall L.

215

Influence of quenched jets on di-hadron correlations  

SciTech Connect

A simple jet absorption model is used to study the influence of hadron pairs produced by quenched jets, on di-hadron angular correlations at intermediate transverse momentum (p{sub T}). We demonstrate that such pairs can dominate both the yield and the shape of angular correlations, and may account for the similar properties between the near-side 'ridge' and the away-side 'double-humped' structure seen in recent data. These hadron pairs also show azimuthal anisotropy which is sensitive to the emission angle of hadrons relative to that of the jet. Measurement of this anisotropy may provide a constraint for elucidating the production mechanism for near- and away-side hadron pairs at intermediate p{sub T}.

Jia Jiangyong [Department of Chemistry, Stony Brook University, Stony Brook, New York 11794 (United States); Physics Department, Brookhaven National Laboratory, Upton, New York 11796 (United States); Lacey, Roy [Department of Chemistry, Stony Brook University, Stony Brook, New York 11794 (United States)

2009-01-15

216

The addition of amides to group 14 (di)-metallenes.  

PubMed

The addition of a series of primary and secondary amides to the group 14 (di)metallenes Mes(2)Si=SiMes(2), Mes(2)Ge=GeMes(2) and (Me(3)Si)(2)Si=C(OSiMe(3))R, where R = t-Bu or R = 1-Ad, was examined. In general, the addition of primary and N-methyl amides gave amide adducts whereas the addition of N-phenyl amides gave imidate adducts. The regiochemistry of the additions was highly dependent upon the substituent bonded to the amide nitrogen. We propose that the formation of the adducts proceeds by way of a zwitterionic intermediate. The reactivity of tetramesityldigermene towards amides is used to predict the structure of the amide adducts formed on the Ge(100)-2 × 1 surface. PMID:22072155

Hardwick, Julie A; Pavelka, Laura C; Baines, Kim M

2012-01-14

217

Hexa-aqua-nickel(II) di-hydrogen hypodiphosphate  

PubMed Central

The asymmetric unit of the title compound, [Ni(H2O)6](H2P2O6), contains one-half of the hexa­aqua­nickel(II) cation and one-half of the di­hydrogen hypodiphosphate anion. In the complex cation, the Ni2+ atom is located on an inversion center and has an octa­hedral coordination sphere. The P—P distance in the centrosymmetric anion is 2.1853?(7)?Å. In the crystal, discrete [Ni(H2O)6]2+ cations and (H2P2O6)2? anions are stacked in columns parallel to the c axis and are linked into a three-dimensional network by medium-strength O—H?O hydrogen bonds.

Gjikaj, Mimoza; Wu, Peng; Pook, Niels-Patrick

2013-01-01

218

Functional Characterization of Core Components of the Bacillus subtilis Cyclic-Di-GMP Signaling Pathway  

PubMed Central

Bis-(3?-5?)-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger that regulates adaptation processes, including biofilm formation, motility, and virulence in Gram-negative bacteria. In this study, we have characterized the core components of a c-di-GMP signaling pathway in the model Gram-positive bacterium Bacillus subtilis. Specifically, we have directly identified and characterized three active diguanylate cyclases, DgcP, DgcK, and DgcW (formerly YtrP, YhcK, and YkoW, respectively), one active c-di-GMP phosphodiesterase, PdeH (formerly YuxH), and a cyclic-diguanylate (c-di-GMP) receptor, DgrA (formerly YpfA). Furthermore, elevation of c-di-GMP levels in B. subtilis led to inhibition of swarming motility, whereas biofilm formation was unaffected. Our work establishes paradigms for Gram-positive c-di-GMP signaling, and we have shown that the concise signaling system identified in B. subtilis serves as a powerful heterologous host for the study of c-di-GMP enzymes from bacteria predicted to possess larger, more-complex signaling systems.

Gao, Xiaohui; Mukherjee, Sampriti; Matthews, Paige M.; Hammad, Loubna A.; Kearns, Daniel B.

2013-01-01

219

The Mucosal Adjuvant Cyclic di-AMP Exerts Immune Stimulatory Effects on Dendritic Cells and Macrophages  

PubMed Central

The cyclic di-nucleotide bis-(3?,5?)-cyclic dimeric adenosine monophosphate (c-di-AMP) is a candidate mucosal adjuvant with proven efficacy in preclinical models. It was shown to promote specific humoral and cellular immune responses following mucosal administration. To date, there is only fragmentary knowledge on the cellular and molecular mode of action of c-di-AMP. Here, we report on the identification of dendritic cells and macrophages as target cells of c-di-AMP. We show that c-di-AMP induces the cell surface up-regulation of T cell co-stimulatory molecules as well as the production of interferon-?. Those responses were characterized by in vitro experiments with murine and human immune cells and in vivo studies in mice. Analyses of dendritic cell subsets revealed conventional dendritic cells as principal responders to stimulation by c-di-AMP. We discuss the impact of the reported antigen presenting cell activation on the previously observed adjuvant effects of c-di-AMP in mouse immunization studies.

Libanova, Rimma; Lienenklaus, Stefan; Weiss, Siegfried; Guzman, Carlos A.

2014-01-01

220

[Tratti psicopatologici, personalità e teoria della mente in un campione di studenti universitari].  

PubMed

riassunto. Scopo. Valutare i tratti psicopatologici, la personalità e la teoria della mente in un campione di studenti universitari e analizzarne le correlazioni con variabili socio-demografiche e accademiche. Materiali e metodi. Sono stati raccolti i dati socio-demografici e accademici di 228 studenti del secondo anno afferenti all'Università del Piemonte Orientale Amedeo Avogadro. Gli studenti hanno completato l'Eysenck Personality Questionnaire-R, la Symptom Checklist-90-R (SCL-90-R) e il test di Teoria della Mente (ToM). Risultati. Il 38,6% degli studenti presentava un elevato distress psicologico; il 30,3% aveva un punteggio anomalo al test ToM. Gli studenti con un punteggio del test ToM al di sotto del cut-off avevano una probabilità significativamente inferiore di avere ripetuto un esame per 3 o più volte rispetto a quelli con una normale performance al test. Non essere sposati ed essere in cura da uno psichiatra erano fattori che influenzavano significativamente la probabilità di ripetere un esame. Gli studenti con punteggio anomalo al test ToM mostravano inoltre caratteristiche specifiche per quanto concerne facoltà frequentata e punteggi all'SCL-90-R. Conclusioni. Si è trovata una correlazione tra performance al test ToM e alcuni indicatori di performance accademica. Gli studenti con un punteggio del test ToM inferiore al cut-off riportavano più sintomi psicopatologici e maggiore distress. Si discutono le implicazioni cliniche. PMID:25000889

Zeppegno, Patrizia; Gramaglia, Carla; Antona, Maria; Gili, Sabrina; Marchisio, Sara; Gogliani, Andrea; Ponzetti, Daniela; Torre, Eugenio

2014-01-01

221

Identification of c-di-GMP derivatives resistant to an EAL domain phosphodiesterase  

PubMed Central

The bacterial second messenger signaling molecule bis-(3?-5?)-cyclic dimeric guanosine monophosphate (c-di-GMP) controls important biological processes such as biofilm formation, virulence response, and motility. This second messenger is sensed by macromolecular targets inside the cell, both protein and RNA, which induce specific phenotypic responses critical for bacterial survival. One class of enzymes responsible for regulating the intracellular concentration of c-di-GMP, and therefore the physiological behavior of the cell, is the EAL domain phosphodiesterases, which degrade the second messenger to its linear form, pGpG. Here, we investigate how base and backbone modifications to c-di-GMP affect the rate of cyclic dinucleotide degradation by an EAL domain protein (CC3396 from Caulobacter crescentus). The doubly substituted thiophosphate analog is highly resistant to hydrolysis by this metabolizing enzyme but can still bind c-di-GMP riboswitch targets. We used these findings to develop a novel ribosyl-phosphate modified derivative of c-di-GMP containing 2?-deoxy and methylphosphonate substitutions that is charge neutral and demonstrate that this analog is also resistant to EAL domain catalyzed degradation. This suggests a general strategy for designing c-di-GMP derivatives with increased enzymatic stability that also possess desirable properties for development as chemical probes of c-di-GMP signaling.

Shanahan, Carly A.; Gaffney, Barbara L.; Jones, Roger A.; Strobel, Scott A.

2013-01-01

222

Structural and biochemical determinants of ligand binding by the c-di-GMP riboswitch†,‡  

PubMed Central

The bacterial second messenger c-di-GMP is used in many species to control essential processes that allow the organism to adapt to its environment. The c-di-GMP riboswitch (GEMM) is an important downstream target in this signaling pathway and alters gene expression in response to changing concentrations of c-di-GMP. The riboswitch selectively recognizes its second messenger ligand primarily through contacts with two critical nucleotides. However, these two nucleotides are not the most highly conserved residues within the riboswitch sequence. Instead, nucleotides that stack with c-di-GMP and that form tertiary RNA contacts are the most invariant. Biochemical and structural evidence reveals that the most common natural variants are able to make alternative pairing interactions with both guanine bases of the ligand. Additionally, a high resolution (2.3 Å) crystal structure of the native complex reveals that a single metal coordinates the c-di-GMP backbone. Evidence is also provided that after transcription of the first nucleotide on the 3?-side of the P1 helix, which is predicted to be the molecular switch, the aptamer is functional for ligand binding. Although large energetic effects occur when several residues in the RNA are altered, mutations at the most conserved positions, rather than at positions that base pair with c-di-GMP, have the most detrimental effects on binding. Many mutants retain sufficient c-di-GMP affinity for the RNA to remain biologically relevant, which suggests that this motif is quite resilient to mutation.

Smith, Kathryn D.; Lipchock, Sarah V.; Livingston, Alison L.; Shanahan, Carly A.; Strobel, Scott A.

2011-01-01

223

GTPase activity of Di-Ras proteins is stimulated by Rap1GAP proteins.  

PubMed

The Ras family is the largest and most diverse sub-group of Ras-like G proteins. This complexity is further increased by the high number of regulatory Guanine nucleotide Exchange Factors (GEFs) and GTPase Activating Proteins (GAPs) that target specific members of this subfamily. Di-Ras1 and Di-Ras2 are little characterized members of the Ras-like sub-group with still unidentified regulatory and effector proteins. Here we determined the nucleotide binding properties of Di-Ras1/Di-Ras2. The above nanomolar affinity and the inability to react with members of the Cdc25 RasGEF family might suggest that activation does not require a GEF. We identified Rap1GAP1 and Rap1GAP2 as specific GTPase activating proteins of the Di-Ras family. Dual-specificity GAPs of the GAP1(m) family could not activate Di-Ras proteins, despite the presence of the required catalytic residue. Although Di-Ras proteins share GAPs with Rap G proteins, no common effectors could be identified in vitro. PMID:21686267

Gasper, Raphael; Sot, Begoña; Wittinghofer, Alfred

2010-11-01

224

Functional characterization of core components of the Bacillus subtilis cyclic-di-GMP signaling pathway.  

PubMed

Bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger that regulates adaptation processes, including biofilm formation, motility, and virulence in Gram-negative bacteria. In this study, we have characterized the core components of a c-di-GMP signaling pathway in the model Gram-positive bacterium Bacillus subtilis. Specifically, we have directly identified and characterized three active diguanylate cyclases, DgcP, DgcK, and DgcW (formerly YtrP, YhcK, and YkoW, respectively), one active c-di-GMP phosphodiesterase, PdeH (formerly YuxH), and a cyclic-diguanylate (c-di-GMP) receptor, DgrA (formerly YpfA). Furthermore, elevation of c-di-GMP levels in B. subtilis led to inhibition of swarming motility, whereas biofilm formation was unaffected. Our work establishes paradigms for Gram-positive c-di-GMP signaling, and we have shown that the concise signaling system identified in B. subtilis serves as a powerful heterologous host for the study of c-di-GMP enzymes from bacteria predicted to possess larger, more-complex signaling systems. PMID:23893111

Gao, Xiaohui; Mukherjee, Sampriti; Matthews, Paige M; Hammad, Loubna A; Kearns, Daniel B; Dann, Charles E

2013-11-01

225

Genetic dissection of a motility-associated c-di-GMP signalling protein of Pseudomonas putida.  

PubMed

Lack of the Pseudomonas putida PP2258 protein or its overexpression results in defective motility on solid media. The PP2258 protein is tripartite, possessing a PAS domain linked to two domains associated with turnover of c-di-GMP - a cyclic nucleotide that controls the switch between motile and sessile lifestyles. The second messenger c-di-GMP is produced by diguanylate cyclases and degraded by phosphodiesterases containing GGDEF and EAL or HD-GYP domains respectively. It is common for enzymes involved in c-di-GMP signalling to contain two domains with potentially opposing c-di-GMP turnover activities; however, usually one is degenerate and has been adopted to serve regulatory functions. Only a few proteins have previously been found to have dual enzymatic activities - being capable of both synthesizing and hydrolysing c-di-GMP. Here, using truncated and mutant derivatives of PP2258, we show that despite a lack of complete consensus in either the GGDEF or EAL motifs, the two c-di-GMP turnover domains can function independently of each other, and that the diguanylate cyclase activity is regulated by an inhibitory I-site within its GGDEF domain. Thus, motility-associated PP2258 can be added to the short list of bifunctional c-di-GMP signalling proteins. PMID:23864570

Österberg, Sofia; Åberg, Anna; Herrera Seitz, M Karina; Wolf-Watz, Magnus; Shingler, Victoria

2013-08-01

226

Cytotoxic activity and apoptosis-inducing potential of di-spiropyrrolidino and di-spiropyrrolizidino oxindole andrographolide derivatives.  

PubMed

Anticancer role of andrographolide is well documented. To find novel potent derivatives with improved cytotoxicity than andrographolide on cancer cells, two series of di-spiropyrrolidino- and di-spiropyrrolizidino oxindole andrographolide derivatives prepared by cyclo-addition of azomethine ylide along with sarcosine or proline (viz. sarcosine and proline series respectively) and substitution of different functional groups (-CH3, -OCH3 and halogens) were examined for their cytotoxic effect on a panel of six human cancer cell lines (colorectal carcinoma HCT116 cells, pancreatic carcinoma MiaPaCa-2 cells, hepatocarcinoma HepG2 cells, cervical carcinoma HeLa cells, lung carcinoma A549 and melanoma A375 cells). Except halogen substituted derivatives of proline series (viz. CY2, CY14 and CY15 for Br, Cl and I substitution respectively), none of the other derivatives showed improved cytotoxicity than andrographolide in the cancer cell lines examined. Order of cytotoxicity of the potent compounds is CY2>CY14>CY15>andrographolide. Higher toxicity was observed in HCT116, MiaPaCa-2 and HepG2 cells. CY2, induced death of HCT116 (GI50 10.5), MiaPaCa-2 (GI50 11.2) and HepG2 (GI50 16.6) cells were associated with cell rounding, nuclear fragmentation and increased percentage of apoptotic cells, cell cycle arrest at G1 phase, ROS generation, and involvement of mitochondrial pathway. Upregulation of Bax, Bad, p53, caspases-3,-9 and cleaved PARP; downregulation of Bcl-2, cytosolic NF-?B p65, PI3K and p-Akt; translocation of P53/P21, NF-?B p65 were seen in CY2 treated HCT116 cells. Thus, three halogenated di-spiropyrrolizidino oxindole derivatives of andrographolide are found to be more cytotoxic than andrographolide in some cancer cells. The most potent derivative, CY2 induced death of the cancer cells involves ROS dependent mitochondrial pathway like andrographolide. PMID:23472133

Dey, Sumit Kumar; Bose, Dipayan; Hazra, Abhijit; Naskar, Subhendu; Nandy, Abhishek; Munda, Rudra Narayan; Das, Subhadip; Chatterjee, Nabanita; Mondal, Nirup Bikash; Banerjee, Sukdeb; Saha, Krishna Das

2013-01-01

227

Cytotoxic Activity and Apoptosis-Inducing Potential of Di-spiropyrrolidino and Di-spiropyrrolizidino Oxindole Andrographolide Derivatives  

PubMed Central

Anticancer role of andrographolide is well documented. To find novel potent derivatives with improved cytotoxicity than andrographolide on cancer cells, two series of di-spiropyrrolidino- and di-spiropyrrolizidino oxindole andrographolide derivatives prepared by cyclo-addition of azomethine ylide along with sarcosine or proline (viz. sarcosine and proline series respectively) and substitution of different functional groups (-CH3, -OCH3 and halogens) were examined for their cytotoxic effect on a panel of six human cancer cell lines (colorectal carcinoma HCT116 cells, pancreatic carcinoma MiaPaCa-2 cells, hepatocarcinoma HepG2 cells, cervical carcinoma HeLa cells, lung carcinoma A549 and melanoma A375 cells). Except halogen substituted derivatives of proline series (viz. CY2, CY14 and CY15 for Br, Cl and I substitution respectively), none of the other derivatives showed improved cytotoxicity than andrographolide in the cancer cell lines examined. Order of cytotoxicity of the potent compounds is CY2>CY14>CY15>andrographolide. Higher toxicity was observed in HCT116, MiaPaCa-2 and HepG2 cells. CY2, induced death of HCT116 (GI50 10.5), MiaPaCa-2 (GI50 11.2) and HepG2 (GI50 16.6) cells were associated with cell rounding, nuclear fragmentation and increased percentage of apoptotic cells, cell cycle arrest at G1 phase, ROS generation, and involvement of mitochondrial pathway. Upregulation of Bax, Bad, p53, caspases-3,-9 and cleaved PARP; downregulation of Bcl-2, cytosolic NF-?B p65, PI3K and p-Akt; translocation of P53/P21, NF-?B p65 were seen in CY2 treated HCT116 cells. Thus, three halogenated di-spiropyrrolizidino oxindole derivatives of andrographolide are found to be more cytotoxic than andrographolide in some cancer cells. The most potent derivative, CY2 induced death of the cancer cells involves ROS dependent mitochondrial pathway like andrographolide.

Hazra, Abhijit; Naskar, Subhendu; Nandy, Abhishek; Munda, Rudra Narayan; Das, Subhadip; Chatterjee, Nabanita; Mondal, Nirup Bikash; Banerjee, Sukdeb; Saha, Krishna Das

2013-01-01

228

Fluorescence-Based Reporter for Gauging Cyclic Di-GMP Levels in Pseudomonas aeruginosa  

PubMed Central

The increased tolerance toward the host immune system and antibiotics displayed by biofilm-forming Pseudomonas aeruginosa and other bacteria in chronic infections such as cystic fibrosis bronchopneumonia is of major concern. Targeting of biofilm formation is believed to be a key aspect in the development of novel antipathogenic drugs that can augment the effect of classic antibiotics by decreasing antimicrobial tolerance. The second messenger cyclic di-GMP is a positive regulator of biofilm formation, and cyclic di-GMP signaling is now regarded as a potential target for the development of antipathogenic compounds. Here we describe the development of fluorescent monitors that can gauge the cellular level of cyclic di-GMP in P. aeruginosa. We have created cyclic di-GMP level reporters by transcriptionally fusing the cyclic di-GMP-responsive cdrA promoter to genes encoding green fluorescent protein. We show that the reporter constructs give a fluorescent readout of the intracellular level of cyclic di-GMP in P. aeruginosa strains with different levels of cyclic di-GMP. Furthermore, we show that the reporters are able to detect increased turnover of cyclic di-GMP mediated by treatment of P. aeruginosa with the phosphodiesterase inducer nitric oxide. Considering that biofilm formation is a necessity for the subsequent development of a chronic infection and therefore a pathogenicity trait, the reporters display a significant potential for use in the identification of novel antipathogenic compounds targeting cyclic di-GMP signaling, as well as for use in research aiming at understanding the biofilm biology of P. aeruginosa.

Rybtke, Morten T.; Borlee, Bradley R.; Murakami, Keiji; Irie, Yasuhiko; Hentzer, Morten; Nielsen, Thomas E.; Givskov, Michael; Parsek, Matthew R.

2012-01-01

229

Cyclic di-GMP inhibits Vibrio cholerae motility by repressing induction of transcription and inducing extracellular polysaccharide production.  

PubMed

Cyclic di-GMP (c-di-GMP) controls the transition between sessility and motility in many bacterial species. This regulation is achieved by a variety of mechanisms including alteration of transcription initiation and inhibition of flagellar function. How c-di-GMP inhibits the motility of Vibrio cholerae has not been determined.?FlrA, a homologue of the c-di-GMP binding Pseudomonas aeruginosa motility regulator FleQ, is the master regulator of the V.?cholerae flagellar biosynthesis regulon. Here we show that binding of c-di-GMP to FlrA abrogates binding of FlrA to the promoter of the flrBC operon, deactivating expression of the flagellar biosynthesis regulon. FlrA does not regulate expression of extracellular Vibrio polysaccharide (VPS) synthesis genes. Mutation of the FlrA amino acids R135 and R176 to histidine abrogates binding of c-di-GMP to FlrA, rendering FlrA active in the presence of high levels of c-di-GMP. Surprisingly, c-di-GMP still inhibited the motility of V.?cholerae only expressing the c-di-GMP blind FlrA(R176H) mutant. We determined that this flagellar transcription-independent inhibition is due to activation of VPS production by c-di-GMP. Therefore, c-di-GMP prevents motility of V.?cholerae by two distinct but functionally redundant mechanisms. PMID:24134710

Srivastava, Disha; Hsieh, Meng-Lun; Khataokar, Atul; Neiditch, Matthew B; Waters, Christopher M

2013-12-01

230

Di-aqua-bis-(pyridine-2-carboxyl-ato-?(2) N,O)zinc di-methyl-formamide hemisolvate.  

PubMed

In the title compound, [Zn(C6H4NO2)2(H2O)2]·0.5C3H7NO, the Zn(II) ion is coordinated in a distorted octa-hedral N2O4 environment by two N,O-chelating pyridine-2-carboxyl-ate ligands and two cis water mol-ecules. The chelating pyridine-2-carboxyl-ate ligands create two five-membered Zn/N/C/C/O rings, which form a dihedral angle of 86.4?(2)°. In the crystal, O-H?O hydrogen bonds link the complex mol-ecules into a two-dimensional network parallel to (100). The di-methyl-formamide solvent mol-ecule is disordered about a twofold rotation axis. PMID:24109277

Croitor, Lilia; Chisca, Diana; Coropceanu, Eduard B; Fonari, Marina S

2013-01-01

231

Poly[(?3-5-tert-butyl-benzene-1,3-di-carboxyl-ato)di-pyridine-cobalt(II)  

PubMed Central

In the title compound, [Co(C12H12O4)(C5H5N)2]n, the CoII cation is coordinated by four O atoms from three 5-tert-butyl­benzene-1,3-di­carboxyl­ate anions and two N atoms from pyridine mol­ecules in a distorted octa­hedral geometry. One carboxyl­ate group of the anionic ligand chelates a CoII cation while another carboxyl­ate group bridges two CoII cations, resulting in a polymeric layer parallel to (101). Weak C—H?O hydrogen bonds occur between adjacent polymeric layers. In the crystal, one of pyridine mol­ecules is equally disordered over two positions.

Noh, Kyungkyou; Kim, Jaheon

2013-01-01

232

4,4'-{[1,2-Phenyl-enebis(methyl-ene)]bis-(-oxy)}di-benzoic acid di-methyl-formamide disolvate.  

PubMed

In the title solvate, C22H18O6·2C3H7NO, the complete dicarboxylic acid molecule is generated by a crystallographic twofold axis, which bisects the central benzene ring and one N,N-di-methyl-formamide solvent mol-ecule. The dihedral angle between the central and pendant benzene rings is 54.53?(5)° while that between the pendant rings is 45.44?(5)°. In the crystal, the acid molecules are linked to the solvent molecules via O-H?O and weak C-H?O hydrogen bonds. Further weak C-H?O inter-actions link adjacent acid mol-ecules into a three-dimensional network. PMID:24860345

Qiu, Zhen-Zhe; Jing, Bi; Li, Qiu-Xia; Zhu, Ai-Xin

2014-05-01

233

Cellular Levels and Binding of c-di-GMP Control Subcellular Localization and Activity of the Vibrio cholerae Transcriptional Regulator VpsT  

Microsoft Academic Search

The second messenger, cyclic diguanylate (c-di-GMP), regulates diverse cellular processes in bacteria. C-di-GMP is produced by diguanylate cyclases (DGCs), degraded by phosphodiesterases (PDEs), and receptors couple c-di-GMP production to cellular responses. In many bacteria, including Vibrio cholerae, multiple DGCs and PDEs contribute to c-di-GMP signaling, and it is currently unclear whether the compartmentalization of c-di-GMP signaling components is required to

Nicholas J. Shikuma; Jiunn C. N. Fong; Fitnat H. Yildiz

2012-01-01

234

Combination of diOlistic labeling with retrograde tract tracing and immunohistochemistry.  

PubMed

Neuronal staining techniques have played a crucial role in the analysis of neuronal function. Several different staining techniques have been developed to allow morphological analyses of neurons. DiOlistic labeling, in which beads are coated with a lipophilic dye and then ballistically ejected onto brain tissue, has recently been introduced as a useful and simple means to label neurons and glia in their entirety. Although diOlistic labeling provides detailed information on the morphology of neurons, combining this approach with other staining methods is a significant advance. We have developed protocols that result in high quality diOlistically- and retrogradely-labeled or diOlistically-immunohistochemically labeled neurons. These dual-label methods require modification of fixation parameters and the restricted use of detergents for tissue permeabilization, and are readily applicable to a wide range of tracers and antibodies. PMID:19712695

Neely, M Diana; Stanwood, Gregg D; Deutch, Ariel Y

2009-11-15

235

ProbDiVinE: A Parallel Qualitative LTL Model Checker  

Microsoft Academic Search

introduce a parallel model checker for checking Markov decision processes against linear time properties. The model checker extends the parallel model checker DiVinE and supports verification of qualitative properties.

J. Barnat; L. Brim; I. Cerna; M. Ceska; J. Tumova

2007-01-01

236

Disappearance of Tri-, Di-, and Monoglycerides From the Circulation of Dogs.  

National Technical Information Service (NTIS)

Artificial emulsions of cotton seed oil were rapidly infused intravenously into unanesthetized dogs. Arterial blood samples were withdrawn at timed intervals and plasma volume and plasma levels of tri-, di-, and monoglycerides were quantitatively measured...

E. W. Askew J. B. Vacca M. Nugent P. P. Waring R. M. Nims

1973-01-01

237

Zirconium and Niobium Extraction from HCl Media with di-N-Butyl Phosphorodithioic Acid.  

National Technical Information Service (NTIS)

The solvent extraction of zirconium and niobium di-n-butyl phosphoroditioate into organic diluents from HCl media is presented. The effect of extractant and mineral acid concentration on the zirconium and niobium distribution ratios as plots of lg. distri...

V. C. Iliescu

1978-01-01

238

Safety Assessment of Di(2-ethylhexyl)phthalate (DEHP) Released from PVC Medical Devices.  

National Technical Information Service (NTIS)

Patients undergoing medical procedures such as IV therapy, enteral and parenteral nutrition support, blood transfusion, hemodialysis and peritoneal dialysis, cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) can be exposed to di-...

2004-01-01

239

Reactions of (1 R,2 S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane and (1 R,2 S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties  

Microsoft Academic Search

Reactions of the title meso forms, (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane (1) and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane (2), with a two molar amount of TCNE in benzene at 25°C for 5h (for 1) and 48h (for 2) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl-1,4-dihydrocyclohepta[c,d]azulene (3) and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)-1,4-dihydrocyclohepta[c,d]azulene (4), respectively, in 74 and 21% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of

Shin-ichi Takekuma; Kenji Takahashi; Akio Sakaguchi; Masato Sasaki; Toshie Minematsu; Hideko Takekuma

2006-01-01

240

Selective Solvent Extraction of Palladium by the Use of Di-Normal-Hexyl Sulphide.  

National Technical Information Service (NTIS)

A general description of di-N-hexyl sulphide (DNHS) is given, including the synthesis, purification, toxicity, and recycling ability of the extractant. The following parameters were tested for the optimum conditions of separation: mode of mixing, amount a...

H. Renner

1985-01-01

241

BrlR from Pseudomonas aeruginosa is a c-di-GMP-responsive transcription factor.  

PubMed

The transcriptional regulator BrlR is a member of the MerR family of multidrug transport activators that contributes to the high-level drug tolerance of Pseudomonas aeruginosa biofilms. While MerR regulators are known to activate both the expression of multidrug efflux pump genes and their own transcription upon inducer binding, little is known about BrlR activation. We demonstrate using promoter reporter strains, in vivo and in vitro?DNA-binding assays combined with 5'RACE, that BrlR binds to its own promoter, likely via a MerR-like palindromic sequence. Unlike known MerR multidrug transport activators, BrlR and brlR expression are not activated by multidrug transporter substrates. Instead, BrlR-DNA binding was enhanced by the secondary messenger c-di-GMP. In addition to enhanced BrlR-DNA binding, c-di-GMP levels contributed to PbrlR promoter activity in initial attached cells with elevated c-di-GMP levels correlating with increased expression of brlR. While not harbouring amino acid motifs resembling previously defined c-di-GMP-binding domains, BrlR was found to bind c-di-GMP?in vitro at a ratio of one c-di-GMP per two BrlR. Cross-linking assays confirmed dimer formation to be enhanced in the presence of elevated c-di-GMP levels. Our findings demonstrate BrlR to be an unusual MerR-family member in that BrlR function and expression require the secondary messenger c-di-GMP. PMID:24612375

Chambers, Jacob R; Liao, Julie; Schurr, Michael J; Sauer, Karin

2014-05-01

242

PROGETTARE UNA CAMPAGNA DI CONTRO-MARKETING SUL TABACCO PER ADOLESCENTI AFROAMERICANI  

Microsoft Academic Search

L'articolo riporta i risultati di uno studio qualitativo volto a: 1) individuare temi ricorrenti e tattiche utilizzate dall'industria del tabacco per attirare i giovani afroamericani nel mercato delle sigarette e 2) far emergere le conoscenze, gli atteggiamenti, le intenzioni e le credenze dei ragazzi afroamericani in relazione al fumo e all'industria del tabacco, per aiutare a sviluppare campagne di contro-

Francesca Di Stefano

243

The prokaryote messenger c-di-GMP triggers stalk cell differentiation in Dictyostelium.  

PubMed

Cyclic di-(3?:5?)-guanosine monophosphate (c-di-GMP) is a major prokaryote signalling intermediate that is synthesized by diguanylate cyclases and triggers sessility and biofilm formation. We detected the first eukaryote diguanylate cyclases in all major groups of Dictyostelia. On food depletion, Dictyostelium discoideum amoebas collect into aggregates, which first transform into migrating slugs and then into sessile fruiting structures. These structures consist of a spherical spore mass that is supported by a column of stalk cells and a basal disk. A polyketide, DIF-1, which induces stalk-like cells in vitro, was isolated earlier. However, its role in vivo proved recently to be restricted to basal disk formation. Here we show that the Dictyostelium diguanylate cyclase, DgcA, produces c-di-GMP as the morphogen responsible for stalk cell differentiation. Dictyostelium discoideum DgcA synthesized c-di-GMP in a GTP-dependent manner and was expressed at the slug tip, which is the site of stalk cell differentiation. Disruption of the DgcA gene blocked the transition from slug migration to fructification and the expression of stalk genes. Fructification and stalk formation were restored by exposing DgcA-null slugs to wild-type secretion products or to c-di-GMP. Moreover, c-di-GMP, but not cyclic di-(3?:5?)-adenosine monophosphate, induced stalk gene expression in dilute cell monolayers. Apart from identifying the long-elusive stalk-inducing morphogen, our work also identifies a role for c-di-GMP in eukaryotes. PMID:22864416

Chen, Zhi-hui; Schaap, Pauline

2012-08-30

244

Cyclic di-GMP is Essential for the Survival of the Lyme Disease Spirochete in Ticks  

Microsoft Academic Search

Cyclic dimeric GMP (c-di-GMP) is a bacterial second messenger that modulates many biological processes. Although its role in bacterial pathogenesis during mammalian infection has been documented, the role of c-di-GMP in a pathogen's life cycle within a vector host is less understood. The enzootic cycle of the Lyme disease pathogen Borrelia burgdorferi involves both a mammalian host and an Ixodes

Ming He; Zhiming Ouyang; Bryan Troxell; Haijun Xu; Akira Moh; Joseph Piesman; Michael V. Norgard; Mark Gomelsky; X. Frank Yang

2011-01-01

245

Procedure di Mutuo Riconoscimento: Problematiche di Qualita dei Farmaci per Uso Umano Nei Dossier di Autorizzazione All'Immissione in Commercio (Mutual Recognition Procedures: Quality Problems in Dossiers for Marketing Authorization of Pharmaceutical Products for Human Use).  

National Technical Information Service (NTIS)

Quality of a medicinal product is an essential requirement for its safety and efficacy. This first report analyses the evaluation activity of the Istituto Superiore di Sanita (ISS, the National Institute of Health in Italy) on the Quality part of the doss...

I. Sestili M. Bartolomei M. C. Gaudiano

2006-01-01

246

Evoluzione di un Progetto Comunicativo Istituzionale: il Sito Web dell'Istituto Superiore di Sanita. (Evolution of an Institutional Communication Project: the Website of the Istituto Superiore di Sanita).  

National Technical Information Service (NTIS)

The chosen way, based on the accessibility of the Istituto Superiore di Sanitaa (ISS) website, under the current online version, has led to the publication of four previous versions in the last 3 years. At the same time of this technical updating, the ent...

C. Faralli E. Morassi M. Ferrari P. Roazzi S. Guderzo

2009-01-01

247

Two-generation reproduction toxicity studies of di-(C 7-C 9 alkyl) phthalate and di-(C 9-C 11 alkyl) phthalate in the rat  

Microsoft Academic Search

Di-(C7-C9 alkyl) phthalate (D79P) and di-(C9-C11 alkyl) phthalate (D911P), based on high-normality linear oxo-alcohols, have been assessed for their impact upon reproductive performance in Sprague–Dawley rats. Rats were continuously exposed to either D79P or D911P at dietary levels of 0%, 0.1%, 0.5%, or 1.0% over two generations. Selected F0 offspring (F1 generation) were exposed to the same dietary concentration of

Christopher R. Willoughby; Steven M. Fulcher; Dianne M. Creasy; Julian A. Heath; Robert A. J. Priston; Nigel P. Moore

2000-01-01

248

Developmental toxicity of di-(C 7-C 9 alkyl) phthalate and di-(C 9-C 11 alkyl) phthalate in the rat  

Microsoft Academic Search

Two phthalate esters, di-(C7-C9 alkyl) phthalate (D79P) and di-(C9-C11 alkyl) phthalate (D911P), have been assessed for their potential to cause developmental toxicity in the rat. Groups of 22 timed-mated Sprague-Dawley rats were administered 250, 500, or 1000 mg\\/kg D79P or D911P daily by oral gavage (5 ml\\/kg) between gestation days (GD) 1 and 19. Control animals received the vehicle (olive

Steven M. Fulcher; Christopher R. Willoughby; Julian A. Heath; Gauke E. Veenstra; Nigel P. Moore

2000-01-01

249

Cyclic di-GMP signalling and the regulation of bacterial virulence  

PubMed Central

Signal transduction pathways involving the second messenger cyclic di-GMP [bis-(3?-5?)-cyclic di-guanosine monophosphate] occur widely in bacteria where they act to link perception of environmental or intracellular cues and signals to specific alterations in cellular function. Such alterations can contribute to bacterial lifestyle transitions including biofilm formation and virulence. The cellular levels of the nucleotide are controlled through the opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs). The GGDEF domain of DGCs catalyses the synthesis of cyclic di-GMP from GTP, whereas EAL or HD-GYP domains in different classes of PDE catalyse cyclic di-GMP degradation to pGpG and GMP. We are now beginning to understand how alterations in cyclic di-GMP exert a regulatory action through binding to diverse receptors or effectors that include a small ‘adaptor’ protein domain called PilZ, transcription factors and riboswitches. The regulatory action of enzymically active cyclic di-GMP signalling proteins is, however, not restricted to an influence on the level of nucleotide. Here, I will discuss our recent findings that highlight the role that protein–protein interactions involving these signalling proteins have in regulating functions that contribute to bacterial virulence.

2013-01-01

250

Identification of ligand analogues that control c-di-GMP riboswitches.  

PubMed

Riboswitches for the bacterial second messenger c-di-GMP control the expression of genes involved in numerous cellular processes such as virulence, competence, biofilm formation, and flagella synthesis. Therefore, the two known c-di-GMP riboswitch classes represent promising targets for developing novel modulators of bacterial physiology. Here, we examine the binding characteristics of circular and linear c-di-GMP analogues for representatives of both class I and II c-di-GMP riboswitches derived from the pathogenic bacterium Vibrio choleae (class I) and Clostridium difficile (class II). Some compounds exhibit values for apparent dissociation constant (K(D)) below 1 ?M and associate with riboswitch RNAs during transcription with a speed that is sufficient to influence riboswitch function. These findings are consistent with the published structural models for these riboswitches and suggest that large modifications at various positions on the ligand can be made to create novel compounds that target c-di-GMP riboswitches. Moreover, we demonstrate the potential of an engineered allosteric ribozyme for the rapid screening of chemical libraries for compounds that bind c-di-GMP riboswitches. PMID:22646696

Furukawa, Kazuhiro; Gu, Hongzhou; Sudarsan, Narasimhan; Hayakawa, Yoshihiro; Hyodo, Mamoru; Breaker, Ronald R

2012-08-17

251

Structural Basis for c-di-GMP-Mediated Inside-Out Signaling Controlling Periplasmic Proteolysis  

PubMed Central

The bacterial second messenger bis-(3?–5?) cyclic dimeric guanosine monophosphate (c-di-GMP) has emerged as a central regulator for biofilm formation. Increased cellular c-di-GMP levels lead to stable cell attachment, which in Pseudomonas fluorescens requires the transmembrane receptor LapD. LapD exhibits a conserved and widely used modular architecture containing a HAMP domain and degenerate diguanylate cyclase and phosphodiesterase domains. c-di-GMP binding to the LapD degenerate phosphodiesterase domain is communicated via the HAMP relay to the periplasmic domain, triggering sequestration of the protease LapG, thus preventing cleavage of the surface adhesin LapA. Here, we elucidate the molecular mechanism of autoinhibition and activation of LapD based on structure–function analyses and crystal structures of the entire periplasmic domain and the intracellular signaling unit in two different states. In the absence of c-di-GMP, the intracellular module assumes an inactive conformation. Binding of c-di-GMP to the phosphodiesterase domain disrupts the inactive state, permitting the formation of a trans-subunit dimer interface between adjacent phosphodiesterase domains via interactions conserved in c-di-GMP-degrading enzymes. Efficient mechanical coupling of the conformational changes across the membrane is realized through an extensively domain-swapped, unique periplasmic fold. Our structural and functional analyses identified a conserved system for the regulation of periplasmic proteases in a wide variety of bacteria, including many free-living and pathogenic species.

Madden, Dean R.; O'Toole, George A.; Sondermann, Holger

2011-01-01

252

Mechanism of activation of bacterial cellulose synthase by cyclic di-GMP.  

PubMed

The bacterial signaling molecule cyclic di-GMP (c-di-GMP) stimulates the synthesis of bacterial cellulose, which is frequently found in biofilms. Bacterial cellulose is synthesized and translocated across the inner membrane by a complex of cellulose synthase BcsA and BcsB subunits. Here we present crystal structures of the c-di-GMP-activated BcsA-BcsB complex. The structures reveal that c-di-GMP releases an autoinhibited state of the enzyme by breaking a salt bridge that otherwise tethers a conserved gating loop that controls access to and substrate coordination at the active site. Disrupting the salt bridge by mutagenesis generates a constitutively active cellulose synthase. Additionally, the c-di-GMP-activated BcsA-BcsB complex contains a nascent cellulose polymer whose terminal glucose unit rests at a new location above BcsA's active site and is positioned for catalysis. Our mechanistic insights indicate how c-di-GMP allosterically modulates enzymatic functions. PMID:24704788

Morgan, Jacob L W; McNamara, Joshua T; Zimmer, Jochen

2014-05-01

253

Cyclic-di-GMP signalling regulates motility and biofilm formation in Bordetella bronchiseptica  

PubMed Central

The signalling molecule bis-(3?–5?)-cyclic-dimeric guanosine monophosphate (c-di-GMP) is a central regulator of diverse cellular functions, including motility, biofilm formation, cell cycle progression and virulence, in bacteria. Multiple diguanylate cyclase and phosphodiesterase-domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) modulate the levels of the second messenger c-di-GMP to transmit signals and obtain such specific cellular responses. In the genus Bordetella this c-di-GMP network is poorly studied. In this work, we evaluated the expression of two phenotypes in Bordetella bronchiseptica regulated by c-di-GMP, biofilm formation and motility, under the influence of ectopic expression of Pseudomonas aeruginosa proteins with EAL or GGDEF domains that regulates the c-di-GMP level. In agreement with previous reports for other bacteria, we observed that B. bronchiseptica is able to form biofilm and reduce its motility only when GGDEF domain protein is expressed. Moreover we identify a GGDEF domain protein (BB3576) with diguanylate cyclase activity that participates in motility and biofilm regulation in B. bronchiseptica. These results demonstrate for the first time, to our knowledge, the presence of c-di-GMP regulatory signalling in B. bronchiseptica.

Sisti, Federico; Ha, Dae-Gon; O'Toole, George A.; Hozbor, Daniela

2013-01-01

254

Francium sources at Laboratori Nazionali di Legnaro: Design and performance  

SciTech Connect

A facility for the production of radioactive francium is operating at the laboratories of the Istituto Nazionale di Fisica Nucleare (INFN) in Legnaro, Italy. The goal is to collect a cold sample of radioactive atoms in a magneto-optical trap for studies in atomic, nuclear, and particle physics. Production of francium is achieved via the fusion-evaporation reaction {sup 197}Au({sup 18}O,kn){sup 215-k}Fr generated by a {approx}100-MeV {sup 18}O{sup 6+} beam on a thick gold target. The production target is heated to {approx}1200 K and kept at a potential of +3 kV to enhance Fr diffusion and surface desorption. Average production rates are 0.7x10{sup 6} ions/s for {sup 210}Fr with a primary beam flux of 10{sup 12} particles/s, with peaks of 2x10{sup 6} ions/s. Details are given on the design and construction of the production targets and on the measurements that characterize their performance.

Stancari, G.; Veronesi, S.; Corradi, L.; Atutov, S.N.; Calabrese, R.; Dainelli, A.; Mariotti, E.; Moi, L.; Sanguinetti, S.; Tomassetti, L. [Dipartimento di Fisica and INFN, 44100 Ferrara (Italy); Dipartimento di Fisica and INFN, 53100 Siena (Italy); INFN Laboratori Nazionali di Legnaro, 35020 Legnaro PD (Italy); Dipartimento di Fisica and INFN, 44100 Ferrara (Italy); INFN Laboratori Nazionali di Legnaro, 35020 Legnaro PD (Italy); Dipartimento di Fisica and INFN, 53100 Siena (Italy); Dipartimento di Fisica and INFN, 56127 Pisa (Italy); Dipartimento di Fisica and INFN, 44100 Ferrara (Italy)

2006-03-15

255

Mono-, Di-, or Trimorphism in Black Sea Ammonia sp.  

NASA Astrophysics Data System (ADS)

For the genus Ammonia, the size of proloculi was considered one of the valuable taxonomic landmarks, although it may split in first alternating generations. We analysed 140 living (stained) tests of Ammonia sp. from the outer shelf of the Black Sea, collected from 5 stations on a depth gradient (138 to 206 m water depth). Samples were treated by standard technologies, such as live staining, wet sieving, volume detection, counts, and measures by light microscopy. The size of the proloculi was detected, extended by biometric characterisations of 11 measures, 5 qualitative characters, and 4 numerical ratios. Surprisingly, the multitude of test parameters allows the definition of either one highly variable taxon, or several species, or either di- or trimorphism, exclusively resulting from the definition of 'decisive' or 'neglectable' parameters, or parameter subsets. We followed the general taxonomic definition for the species of the genera, and applied, discussed and rejected published criteria considered as taxonomically important. Surprisingly, in result none of the species described hitherto fully correlates with the morphological roundup observed. It is a new species. This conclusion mainly results from the balance of all morphologies, and not from the selection of an ultimate subset.

Altenbach, Alexander V.; Bassler, Barbara

2014-05-01

256

Francium sources at Laboratori Nazionali di Legnaro: Design and performance  

NASA Astrophysics Data System (ADS)

A facility for the production of radioactive francium is operating at the laboratories of the Istituto Nazionale di Fisica Nucleare (INFN) in Legnaro, Italy. The goal is to collect a cold sample of radioactive atoms in a magneto-optical trap for studies in atomic, nuclear, and particle physics. Production of francium is achieved via the fusion-evaporation reaction 197Au(18O,kn)215-kFr generated by a ~100-MeV 18O6+ beam on a thick gold target. The production target is heated to ~1200 K and kept at a potential of +3 kV to enhance Fr diffusion and surface desorption. Average production rates are 0.7×106 ions/s for 210Fr with a primary beam flux of 1012 particles/s, with peaks of 2×106 ions/s. Details are given on the design and construction of the production targets and on the measurements that characterize their performance.

Stancari, G.; Veronesi, S.; Corradi, L.; Atutov, S. N.; Calabrese, R.; Dainelli, A.; Mariotti, E.; Moi, L.; Sanguinetti, S.; Tomassetti, L.

2006-03-01

257

catena-Poly[[di-tert-butyl-tin(IV)]-?-oxalato  

PubMed Central

The title compound, [Sn(C4H9)2(C2O4)]n, an unexpected side product in the reaction of di-tert-butyl­tin(IV) oxide with nitric acid, represents the first diorganotin(IV) oxalate to be structurally characterized. The SnIV atom of the one-dimensional coordination polymer is located on a mirror plane and is coordinated by two chelating oxalate ions with two rather different Sn—O bond lengths of 2.150?(1) and 2.425?(1)?Å, and two t-butyl groups with Sn—C bond lengths of 2.186?(2) and 2.190?(2)?Å. The coordination polyhedron around the SnIV atom is a distorted tetra­gonal disphenoid. The centrosymmetric oxalate ion also has an asymmetric coordination geometry, as reflected by the two slightly different C—O bond lengths of 1.242?(2) and 1.269?(2)?Å. The chains of the polymer propagate along the b-axis direction. Only van der Waals inter­actions are observed between the chains.

Reichelt, Martin; Reuter, Hans

2014-01-01

258

Biotransformation of di(2-ethylhexyl)phthalate by rainbow trout  

SciTech Connect

The biotransformation of di(2-ethylhexyl)phthalate (DEHP) was studied in rainbow trout (Oncorhynchus mykiss) following intravascular administration. Methyl-esterified metabolites were identified using rodent-derived standards and non-linear gradient elution HPLC; metabolites were confirmed by gas chromatography. Similarities between the biotransformation of DEHP by rainbow trout and mammalian species included (a) mono-ethylhexyl phthalate (MEHP) appeared to be the obligatory first step in DEHP metabolism; (b) the phthalate ring was not oxidized; (c) phthalic acid was a minor metabolite; and (d) several metabolites contained multiple oxidations of the 2-ethylhexyl moiety of MEHP. No metabolites unique to rainbow trout were identified. However, fewer oxidized metabolites were identified in rainbow trout than in mammalian species, possibly due to limited mitochondrial metabolism of MEHP in rainbow trout. The amount of biliary MEHP glucuronide after intravascular administration of DEHP was substantially less than reported in rainbow trout exposed to DEHP via the water. Results confirmed that DEHP metabolism in rainbow trout proceeds by initial rapid formation of MEHP, followed by excretion or extensive oxidation by microsomal P450.

Barron, M.G. [RCG/Hagler Bailly, Inc., Boulder, CO (United States); Albro, P.W. [National Inst. of Environmental Health Sciences, Research Triangle Park, NC (United States); Hayton, W.L. [Ohio State Univ., Columbus, OH (United States). College of Pharmacy

1995-05-01

259

Forward di-hadron correlation study at STAR  

NASA Astrophysics Data System (ADS)

Quarks and Gluons, known generically as partons, are the current known fundamental constituents of the proton. The gluon density increases as the longitudinal momentum faction (x) of the gluon decreases, but it cannot increase without bound and saturation is expected at a certain low x value. The dynamics of quarks and gluons at low x is an open question. Studies of correlations between pairs of particles emitted in the forward direction at STAR aim to probe the small-x gluons in protons and in denser nuclear targets like gold. Suppression of back-to-back forward 0? - forward 0? azimuthal correlations which is consistent with Color Glass Condensate (CGC) prediction has been observed in central d+Au collisions at STAR. By studying the rapidity dependence of the forward triggered di-hadron correlations in p+p and d+Au collisions at ?s=200GeV, we aim to address the question of how sharp the transition is in going from a dilute parton gas to the dense parton state. STAR has nearly continuous electromagnetic calorimeter coverage in pseudo-rapidity -1

Li, Xuan

2012-10-01

260

Skin permeation and metabolism of di(2-ethylhexyl) phthalate (DEHP).  

PubMed

Phthalates are suspected to be endocrine disruptors. Di(2-ethylhexyl) phthalate (DEHP) is assumed to have low dermal absorption; however, previous in vitro skin permeation studies have shown large permeation differences. Our aims were to determine DEHP permeation parameters and assess extent of skin DEHP metabolism among workers highly exposed to these lipophilic, low volatile substances. Surgically removed skin from patients undergoing abdominoplasty was immediately dermatomed (800 ?m) and mounted on flow-through diffusion cells (1.77 cm(2)) operating at 32°C with cell culture media (aqueous solution) as the reservoir liquid. The cells were dosed either with neat DEHP or emulsified in aqueous solution (166 ?g/ml). Samples were analysed by HPLC-MS/MS. DEHP permeated human viable skin only as the metabolite MEHP (100%) after 8h of exposure. Human skin was able to further oxidize MEHP to 5-oxo-MEHP. Neat DEHP applied to the skin hardly permeated skin while the aqueous solution readily permeated skin measured in both cases as concentration of MEHP in the receptor liquid. DEHP pass through human skin, detected as MEHP only when emulsified in aqueous solution, and to a far lesser degree when applied neat to the skin. Using results from older in vitro skin permeation studies with non-viable skin may underestimate skin exposures. Our results are in overall agreement with newer phthalate skin permeation studies. PMID:24140552

Hopf, N B; Berthet, A; Vernez, D; Langard, E; Spring, P; Gaudin, R

2014-01-01

261

Laser Ablation Characterization in Laboratori Nazionali di Legnaro  

NASA Astrophysics Data System (ADS)

Using high power laser focalized into a target material generates plasma and it has the consequence to immediately extract and ionize atoms from the target itself. This process is the starting point to have a simple and compact ion source, usually named Laser Ion Source (LIS). This kind of sources are arising in the scenario of ion sources especially in refractory elements ions production, where the atomization of the material to ionize is the main issue because of its high evaporating temperature. These considerations and the fact that ion sources are becoming nowadays more and more important to several fields of science and technology, open an interesting line of research that our group at Laboratori Nazionali di Legnaro wants to investigate. Experiment involves characterization of produced ions by measuring charge state and amount of ions created. Measurements will be performed with several power densities and varying ions collector distance and potential respect to the target. These simple experiments are the necessary preliminary steps to characterize the system and to start a solid future development onto possible different and effective ways to perform ions sources using laser.

Scarpa, D.; Nicolosi, P.; Franci, A.; Tomaselli, A.; Manzolaro, M.; Corradetti, S.; Vasquez, J.; Rossignoli, M.; Calderolla, M.; Monetti, A.; Andrighetto, A.; Prete, G.

2014-04-01

262

L'evoluzione storica del modello di Biggs e della Student Approach to Learning : dall'Information Processing alla valutazione della qualità e delle variabili di contesto dei sistemi u niversitari  

Microsoft Academic Search

Attraverso l'analisi del modello sull'approccio all o studio di Biggs, è stata condotta una rassegna delle ricerche in grado di descrivere il contesto d i nascita e l'evoluzione della cornice teorica denominata Student Approach to Learning . Dalle iniziali ricerche sui processi di studio co ndotte nell'ambito dell' Information Processing , attraverso l'evoluzione dei modelli descrittivi e della ricerca, sino

R. G. Zuffo; M. Barattucci; A. Di Bari

263

Excess molar enthalpies for the binary and ternary mixtures of ether compounds ( di -isopropyl ether, di -butyl ether, propyl vinyl ether) with ethanol and isooctane at 298.15 K  

Microsoft Academic Search

Excess molar enthalpy (H\\u000a E\\u000a ) data at 298.15 K are reported for the binary systems di-isopropyl ether (1)+ethanol (2), di-isopropyl ether (1)+isooctane (2), ethanol (1)+isooctane (2), di-butyl ether (1)+ethanol (2), di-butyl ether (1)+isooctane (2), propyl vinyl ether (1)+ethanol (2) and propyl vinyl ether (1)+isooctane (2). These data were\\u000a obtained by using an isothermal flow calorimeter. The experimental binary H

Moon-Gab Kim; So-Jin Park; In-Chan Hwang

2008-01-01

264

Solidphase oxidation of 2,4Di tert -butylphenol and 3,6Di tert -butylpyrocatechol in the presence of alkali and alkaline earth metal halides under elastic deformation  

Microsoft Academic Search

Solid-phase oxidation of 2,4-di-tert-butylphenol to give 2,2?,4,4?-tert-butyl-6,6?-bisphenol and of 3,6-di-tert-butylpyrocatechol to afford 3,6-di-tert-butyl-l,2-benzoquinone was performed in the presence of alkali and alkaline earth metals halides under conditions of modified\\u000a extrusion. The formation of the corresponding metal 3,6-di-tert-butylsemiquinolates was registered by ESR method. The different behavior of chlorides, bromides, and iodides was observed\\u000a and rationalized basing on the dissimilar complexing ability

V. B. Vol’eva; A. I. Prokof’ev; I. S. Belostotskaya; A. Yu. Karmilov; N. L. Komissarova; T. I. Prokof’eva; V. V. Ershov

2000-01-01

265

Considerazioni sull'uso dei metodi di brain imaging e di strategie sottrattive per lo studio della cognizione e delle sue basi neurali  

Microsoft Academic Search

Metodi non invasivi per la visualizzazione dell'attività cerebrale (brain imaging) sono impiegati da ormai due decenni per lo studio della cognizione e delle sue basi neurali. Il loro impianto metodologico - basato su strategie sottrattive importate da studi comportamentali - si fonda su una serie complessa di assunzioni spesso non tematizzate nella letteratura. Nel loro insieme, queste assunzioni disegnano un

DARIO TARABORELLI

2003-01-01

266

Dinamica di Specie Algali Tossiche nei Laghi di Albano e Nemi (Toxic Algal Species Dynamic in the Lakes of Albano and Nemi).  

National Technical Information Service (NTIS)

The results of a 27 month study (January 2001- April 2003) carried out by the Istituto Superiore di Sanith (the Italian National Institute of Health) have pointed out the presence of two steady populations of the toxic Cyanophycea Planktothrix rubescens i...

M. Bruno V. Messineo D. Mattei S. Melchiorre

2005-01-01

267

De novo asymmetric synthesis of oligo-rhamno di- and tri-saccharides related to the anthrax tetrasaccharide  

PubMed Central

An asymmetric synthesis of the di- and trisaccharide portion of the naturally occurring anthrax tetrasaccharide from acetylfuran has been developed. The construction of the di- and trisaccharide subunits is based upon our previously disclosed route to anthrax tetrasaccharide. The approach uses iterative diastereoselective palladium-catalyzed glycosylations, Luche reductions, diastereoselective dihydroxylations, and regioselective protections for the assembly of the rhamno- di- and tri-saccharide. The route was also modified for the preparation of the mixed D-/L-disaccharide analogue.

Wang, Hua-Yu Leo; Guo, Haibing; O'Doherty, George A.

2013-01-01

268

Atropisomers of Cofacial Heteroaromatic Rings with Two Positive Charges. Derivatives of 1,8-Di(3'-pyridyl)naphthalene.  

PubMed

The two nitrogen atoms in 1,8-di(3'-pyridyl)naphthalene were quaternized by the addition of either benzyl or methyl groups to give dications; the latter was oxidatively converted to the di(6'-pyridone). N-Oxidation gave the mono- and di-N-oxides. All these compounds in DMSO-d(6) show anti-syn atropisomerism at ambient temperatures by (1)H NMR analysis; similar amounts of both diastereomers are present. PMID:11667602

Zoltewicz, John A.; Maier, Nobert M.; Fabian, Walter M. F.

1996-10-01

269

New di-ferrocenyl-ethynylpyridinyl triphenylphosphine copper halide complexes and related di-ferricenyl electro-crystallized materials.  

PubMed

Three new neutral di-ferrocenyl-ethynylpyridinyl copper complexes, [L2(CuCl)2(PPh3)2] (), [L2(CuBr)2(PPh3)2] (), and [L2(CuI)2(PPh3)2] () were synthesized from the ferrocenyl-ethynylpyridine ligand (L) (), the appropriate copper halide CuX (with X = Cl(-), Br(-), I(-)) and triphenylphosphine. These neutral complexes were fully characterized by spectroscopic methods and by single crystal X-ray crystallography. Cyclic voltammetry in dichloroethane revealed chemically reversible ferrocenyl oxidation signals followed by characteristic "stripping reduction peaks" showing evidence for oxidation-product electro-crystallization. Scanning electron microscopy confirmed spontaneous formation of crystalline oxidation products with three distinct morphologies for X = Cl(-), Br(-), I(-). Energy dispersive X-ray elemental analysis data show Fe?:?P ratios of 1?:?2.0, 1?:?2.1 and 1?:?2.1 for electro-crystallization products of complexes , , and , respectively, indicating the presence of two [PF6](-) anions in the vicinity of the dioxidized complexes, and suggesting product formulae [](2+)[PF6](-)2, [](2+)[PF6](-)2 and [](2+)[PF6](-)2. PMID:24824939

Shah, Hakikulla H; Al-Balushi, Rayya A; Al-Suti, Mohammed K; Khan, Muhammad S; Marken, Frank; Sudlow, Anna L; Kociok-Köhn, Gabriele; Woodall, Christopher H; Raithby, Paul R; Molloy, Kieran C

2014-06-01

270

[1,4-Bis(di-phenyl-phosphan-yl)butane-?2 P,P?]di-bromido-palladium(II)  

PubMed Central

In the title complex, [PdBr2(C28H28P2)], the PdII ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis­(di­phenyl­phosphan­yl)butane ligand and two Br? anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294?(7)?Å], making dihedral angles of 66.3?(2), 87.2?(2), 68.8?(2) and 86.8?(2)°. The butyl­ene chain is in a gauche conformation, with a C—C—C—C torsion angle of 57.0?(8)°. Inter­molecular C—H?Br hydrogen bonds link the complex mol­ecules into supra­molecular layers in the ab plane. Weak ?–? inter­actions, both intra- and inter­molecular [shortest inter-centroid distance = 4.598?(5)?Å], are also noted in the three-dimensional architecture.

Ha, Kwang; Song, Yo Soon

2014-01-01

271

[1,4-Bis(di-phenyl-phosphan-yl)butane-?(2) P,P']di-bromido-palladium(II).  

PubMed

In the title complex, [PdBr2(C28H28P2)], the Pd(II) ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis-(di-phenyl-phosphan-yl)butane ligand and two Br(-) anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294?(7)?Å], making dihedral angles of 66.3?(2), 87.2?(2), 68.8?(2) and 86.8?(2)°. The butyl-ene chain is in a gauche conformation, with a C-C-C-C torsion angle of 57.0?(8)°. Inter-molecular C-H?Br hydrogen bonds link the complex mol-ecules into supra-molecular layers in the ab plane. Weak ?-? inter-actions, both intra- and inter-molecular [shortest inter-centroid distance = 4.598?(5)?Å], are also noted in the three-dimensional architecture. PMID:24764813

Ha, Kwang; Song, Yo Soon

2014-02-01

272

Identification of FleQ from Pseudomonas aeruginosa as a c-di-GMP-responsive transcription factor  

PubMed Central

High levels of the intracellular signaling molecule cyclic diguanylate (c-di-GMP) supress motility and activate exopolysaccharide (EPS) production in a variety of bacterial species. In many bacteria part of the effect of c-di-GMP is on gene expression, but the mechanism involved is not known for any species. We have identified the protein FleQ as a c-di-GMP-responsive transcriptional regulator in Pseudomonas aeruginosa. FleQ is known to activate expression of flagella biosynthesis genes. Here we show that it also represses transcription of genes including the pel operon involved in EPS biosynthesis, and that this repression is relieved by c-di-GMP. Our in vivo data indicate that FleQ represses pel transcription and that pel transcription is not repressed when intracellular c-di-GMP levels are high. FleN, a known antiactivator of FleQ also participates in control of pel expression. In in vitro experiments we found that FleQ binds to pel promoter DNA and that this binding is inhibited by c-di-GMP. FleQ binds radiolabeled c-di-GMP in vitro. FleQ does not have amino acid motifs that resemble previously defined c-di-GMP binding domains. Our results show that FleQ is a new type of c-di-GMP binding protein that controls the transcriptional regulation of EPS biosynthesis genes in P. aeruginosa.

Hickman, Jason W.; Harwood, Caroline S.

2008-01-01

273

Nucleotide, c-di-GMP, c-di-AMP, cGMP, cAMP, (p)ppGpp signaling in bacteria and implications in pathogenesis.  

PubMed

For an organism to survive, it must be able to sense its environment and regulate physiological processes accordingly. Understanding how bacteria integrate signals from various environmental factors and quorum sensing autoinducers to regulate the metabolism of various nucleotide second messengers c-di-GMP, c-di-AMP, cGMP, cAMP and ppGpp, which control several key processes required for adaptation is key for efforts to develop agents to curb bacterial infections. In this review, we provide an update of nucleotide signaling in bacteria and show how these signals intersect or integrate to regulate the bacterial phenotype. The intracellular concentrations of nucleotide second messengers in bacteria are regulated by synthases and phosphodiesterases and a significant number of these metabolism enzymes had been biochemically characterized but it is only in the last few years that the effector proteins and RNA riboswitches, which regulate bacterial physiology upon binding to nucleotides, have been identified and characterized by biochemical and structural methods. C-di-GMP, in particular, has attracted immense interest because it is found in many bacteria and regulate both biofilm formation and virulence factors production. In this review, we discuss how the activities of various c-di-GMP effector proteins and riboswitches are modulated upon c-di-GMP binding. Using V. cholerae, E. coli and B. subtilis as models, we discuss how both environmental factors and quorum sensing autoinducers regulate the metabolism and/or processing of nucleotide second messengers. The chemical syntheses of the various nucleotide second messengers and the use of analogs thereof as antibiofilm or immune modulators are also discussed. PMID:23023210

Kalia, Dimpy; Merey, Gökçe; Nakayama, Shizuka; Zheng, Yue; Zhou, Jie; Luo, Yiling; Guo, Min; Roembke, Benjamin T; Sintim, Herman O

2013-01-01

274

Synthesis of 2,3UNSATURATED 4Amino Sugars and Cyclohexyl 2,3-Di-O-Acetyl-4,6-Di-O-Methyl-?-D-Manno-Pyranoside from Cyclohexyl 4,6-Di-O-Acetyl-2,3-Dideoxy-?-D-erythro-Hex-2-Enopyranoside  

Microsoft Academic Search

The synthesis of three 2,3-unsaturated 4-amino sugars 2-4 and cyclohexyl 2,3-di-O-acetyl-4,6-di-O-methyl-?-D-mannopyranoside 8 starting from cyclohexyl 4,6-di-O-acetyl-2,3-dideoxy-?-D-erythro-hex-2-enopyranoside 1 is described. The amino sugars were prepared by allylic substitution using a palladium catalyst.

Tânia M. B. de Brito; Ladjane P. da Silva; Valdenis L. Siqueira; R. M. Srivastava

1999-01-01

275

Constraint on di-nucleotides by codon usage bias in bacterial genomes.  

PubMed

It has been reported earlier that the relative di-nucleotide frequency (RDF) in different parts of a genome is similar while the frequency is variable among different genomes. So RDF is termed as genome signature in bacteria. It is not known if the constancy in RDF is governed by genome wide mutational bias or by selection. Here we did comparative analysis of RDF between the inter-genic and the coding sequences in seventeen bacterial genomes, whose gene expression data was available. The constraint on di-nucleotides was found to be higher in the coding sequences than that in the inter-genic regions and the constraint at the 2nd codon position was more than that in the 3rd position within a genome. Further analysis revealed that the constraint on di-nucleotides at the 2nd codon position is greater in the high expression genes (HEG) than that in the whole genomes as well as in the low expression genes (LEG). We analyzed RDF at the 2nd and the 3rd codon positions in simulated coding sequences that were computationally generated by keeping the codon usage bias (CUB) according to genome G+C composition and the sequence of amino acids unaltered. In the simulated coding sequences, the constraint observed was significantly low and no significant difference was observed between the HEG and the LEG in terms of di-nucleotide constraint. This indicated that the greater constraint on di-nucleotides in the HEG was due to the stronger selection on CUB in these genes in comparison to the LEG within a genome. Further, we did comparative analyses of the RDF in the HEG rpoB and rpoC of 199 bacteria, which revealed a common pattern of constraints on di-nucleotides at the 2nd codon position across these bacteria. To validate the role of CUB on di-nucleotide constraint, we analyzed RDF at the 2nd and the 3rd codon positions in simulated rpoB/rpoC sequences. The analysis revealed that selection on CUB is an important attribute for the constraint on di-nucleotides at these positions in bacterial genomes. We believe that this study has come with major findings of the role of CUB on di-nucleotide constraint in bacterial genomes. PMID:24333347

Satapathy, Siddhartha Sankar; Powdel, Bhes Raj; Dutta, Malay; Buragohain, Alak Kumar; Ray, Suvendra Kumar

2014-02-15

276

Cyclic-diGMP signal transduction systems in Vibrio cholerae: modulation of rugosity and biofilm formation.  

PubMed

Cyclic di-guanylic acid (c-diGMP) is a second messenger that modulates the cell surface properties of several microorganisms. Concentrations of c-diGMP in the cell are controlled by the opposing activities of diguanylate cyclases and phosphodiesterases, which are carried out by proteins harbouring GGDEF and EAL domains respectively. In this study, we report that the cellular levels of c-diGMP are higher in the Vibrio cholerae rugose variant compared with the smooth variant. Modulation of cellular c-diGMP levels by overexpressing proteins with GGDEF or EAL domains increased or decreased colony rugosity respectively. Several genes encoding proteins with either GGDEF or EAL domains are differentially expressed between the two V. cholerae variants. The generation and characterization of null mutants of these genes (cdgA-E, rocS and mbaA) revealed that rugose colony formation, exopolysaccharide production, motility and biofilm formation are controlled by their action. Furthermore, epistasis analysis suggested that cdgC, rocS and mbaA act in convergent pathways to regulate the phenotypic properties of the rugose and smooth variants, and are part of the VpsR, VpsT and HapR signal transduction pathway. PMID:16573684

Lim, Bentley; Beyhan, Sinem; Meir, James; Yildiz, Fitnat H

2006-04-01

277

Engineering a Novel c-di-GMP-Binding Protein for Biofilm Dispersal  

PubMed Central

SUMMARY Bacteria prefer to grow attached to themselves or an interface, and it is important for an array of applications to make biofilms disperse. Here we report simultaneously the discovery and protein engineering of BdcA (formerly YjgI) for biofilm dispersal using the universal signal 3,5-cyclic diguanylic acid (c-di-GMP). The bdcA deletion reduced biofilm dispersal, and production of BdcA increased biofilm dispersal to wild-type levels. Since BdcA increases motility and extracellular DNA production while decreasing exopolysaccharide, cell length, and aggregation, we reasoned that BdcA decreases the concentration of c-di-GMP, the intracellular messenger that controls cell motility through flagellar rotation and biofilm formation through synthesis of curli and cellulose. Consistently, c-di-GMP levels increase upon deleting bdcA, and purified BdcA binds c-di-GMP but does not act as a phosphodiesterase. Additionally, BdcR (formerly YjgJ) is a negative regulator of bdcA. To increase biofilm dispersal, we used protein engineering to evolve BdcA for greater c-di-GMP binding and found that the single amino acid change E50Q causes nearly complete removal of biofilms via dispersal without affecting initial biofilm formation.

Ma, Qun; Yang, Zhonghua; Pu, Mingming; Peti, Wolfgang; Wood, Thomas K.

2010-01-01

278

Production and structure elucidation of di- and oligosaccharide lipids (biosurfactants) from Tsukamurella sp. nov.  

PubMed

The bacterium Tsukamurella sp. nov., isolated from soil, was found to produce novel glycolipids when grown on sunflower oil as the sole carbon source. The glycolipids were isolated by chromatography on silica columns and their structures elucidated using a combination of multidimensional NMR and MS techniques. The three main components are 2,3-di-O-acyl-alpha-D-glucopyranosyl-(1-1)-alpha-D-glucopyranose, 2,3-di-O-acyl-beta-D-glucopyranosyl-(1-2)-4,6-di-O-acyl-alpha-D- glucopyranosyl-(1-1)-alpha-D-glucopyranose and 2,3-di-O-acyl-beta-D-glucopyranosyl-(1-2)-beta-D-galactopyranosyl- (1-6)-4,6-di-O-acyl-alpha-D-glucopyranosyl-(1-1)-alpha-D- glucopyranosyl which are linked to fatty acids varying in chain length from C4 to C18. The glycolipids are mainly extracellular but are also found attached to the cell walls. During the cultivation the composition of the glycolipids changed from disaccharide- to tri- and tetrasaccharide lipids. The glycolipids show good surface-active behaviour and have antimicrobial properties. PMID:9866171

Vollbrecht, E; Heckmann, R; Wray, V; Nimtz, M; Lang, S

1998-11-01

279

Structural insight into the mechanism of cyclic di-GMP hydrolysis by EAL domain phosphodiesterases  

PubMed Central

Cyclic diguanylate (c-di-GMP) is a ubiquitous second messenger regulating diverse cellular functions including motility, biofilm formation, cell cycle progression and virulence in bacteria. In the cell, degradation of c-di-GMP is catalyzed by highly specific EAL domain phosphodiesterases whose catalytic mechanism is still unclear. Here, we purified 13 EAL domain proteins from various organisms and demonstrated that their catalytic activity is associated with the presence of 10 conserved EAL domain residues. The crystal structure of the TDB1265 EAL domain was determined in a free state (1.8 Å) and in complex with c-di-GMP (2.35 Å) and unveiled the role of the conserved residues in substrate binding and catalysis. The structure revealed the presence of two metal ions directly coordinated by six conserved residues, two oxygens of the c-di-GMP phosphate, and potential catalytic water molecule. Our results support a two-metal-ion catalytic mechanism of c-di-GMP hydrolysis by EAL domain phosphodiesterases.

Tchigvintsev, Anatoli; Xu, Xiaohui; Singer, Alexander; Chang, Changsoo; Brown, Greg; Proudfoot, Michael; Cui, Hong; Flick, Robert; Anderson, Wayne F.; Joachimiak, Andrzej; Galperin, Michael Y.; Savchenko, Alexei; Yakunin, Alexander F.

2010-01-01

280

Diethyl 4-(2-meth-oxy-phen-yl)-2,6-di-methyl-1,4-di-hydro-pyridine-3,5-di-carboxyl-ate.  

PubMed

In the title compound, C20H25NO5, the di-hydro-pyridine ring adopts a flattened boat conformation. The meth-oxy-phenyl ring is almost perpendicular to the mean plane of the pyridine ring [dihedral angle = 88.42?(3)°]. The two carbonyl units adopt a synperiplanar conformation with respect to the double bonds in the di-hydro-pyridine ring. In the crystal, mol-ecules are connected by N-H?O hydrogen bonds into R 4 (4)(24) tetra-meric rings. A region of disordered electron density, located at the center of four adjacent mol-ecules, was treated with the SQUEEZE routine in PLATON [Spek (2009 ?). Acta Cryst. D65, 148-155]. It is probably the result of traces of the solvent of crystallization and was not taken into account during the structure refinement. PMID:23723929

Wang, Ke; Wang, Yifeng; Yao, Minjie; Xu, Danqian

2013-05-01

281

Bis(4-meth-oxy-3,4-di-hydro-quinazolin-1-ium) chloranilate.  

PubMed

IN THE TITLE COMPOUND [SYSTEMATIC NAME: bis-(4-meth-oxy-3,4-di-hydro-quinazolin-1-ium) 2,5-di-chloro-3,6-dioxo-cyclo-hexa-1,4-diene-1,4-diolate], 2C9H11N2O(+)·C6Cl2O4 (2-), the chloranil-ate anion lies about an inversion center. The 4-meth-oxy-3,4-di-hydro-quinazolin-1-ium cations are linked on both sides of the anion via bifurcated N-H?(O,O) and weak C-H?O hydrogen bonds, giving a centrosymmetric 2:1 aggregate. The 2:1 aggregates are linked by another N-H?O hydrogen bond into a tape running along [1-10]. The tapes are further linked by a C-H?O hydrogen bond into a layer parallel to the ab plane. PMID:24427103

Gotoh, Kazuma; Ishida, Hiroyuki

2013-01-01

282

MauG: a di-heme enzyme required for methylamine dehydrogenase maturation  

PubMed Central

Methylamine dehydrogenase (MADH) requires the cofactor tryptophan tryptophylquinone (TTQ) for activity. TTQ is a posttranslational modification that results from an 8-electron oxidation of two specific tryptophans in the MADH ?-subunit. The final 6-electron oxidation is catalyzed by an unusual c-type di-heme enzyme, MauG. The di-ferric enzyme can react with H2O2, but atypically for c-type hemes the di-ferrous enzyme can react with O2 as well. In both cases, an unprecedented bis-Fe(IV) redox state is formed, composed of a ferryl heme (Fe(IV)=O) and the second heme as Fe(IV) stabilized by His–Tyr axial ligation. Bis-Fe(IV) MauG acts as a potent 2-electron oxidant. Catalysis is long-range and requires a hole hopping electron transfer mechanism. This review highlights the current knowledge and focus of research into this fascinating system.

Wilmot, Carrie M.; Yukl, Erik T.

2012-01-01

283

6,8-Di-bromo-3-nitro-2-phenyl-2H-chromene.  

PubMed

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar (r.m.s. deviation from planarity = 0.0888?Å). The di-hydro-pyran ring adopts an envelope conformation with the phenyl-substituted C atom fused to the di-hydro-pyran ring as the flap. The dihedral angle between the plane defined by this C atom and the adjacent C and O atoms and the mean plane of the di-hydro-pyran ring excluding the phenyl-substituted C atom is 25.1?(3)°. The dihedral angle between the mean plane of the chromene unit and the phenyl ring is 85.7?(1)°. The crystal structure features C-H?O hydrogen bonds and Br?O contacts [3.289?(3)?Å] involving the nitro O atoms. PMID:23795054

Yan, Lin-Jie; Zhang, Sheng-Yong

2013-06-01

284

6,8-Di-bromo-3-nitro-2-phenyl-2H-chromene  

PubMed Central

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar (r.m.s. deviation from planarity = 0.0888?Å). The di­hydro­pyran ring adopts an envelope conformation with the phenyl-substituted C atom fused to the di­hydro­pyran ring as the flap. The dihedral angle between the plane defined by this C atom and the adjacent C and O atoms and the mean plane of the di­hydro­pyran ring excluding the phenyl-substituted C atom is 25.1?(3)°. The dihedral angle between the mean plane of the chromene unit and the phenyl ring is 85.7?(1)°. The crystal structure features C—H?O hydrogen bonds and Br?O contacts [3.289?(3)?Å] involving the nitro O atoms.

Yan, Lin-Jie; Zhang, Sheng-Yong

2013-01-01

285

Thermal remote sensing of Thom's discomfort index (DI): comparison with in-situ measurements  

NASA Astrophysics Data System (ADS)

The bioclimatic index most commonly used in urban climate studies to describe the level of thermal sensation that a person experiences due to the modified climatic conditions of an urban area, is the discomfort index (DI) of Thom. DI reflects the proportionate contribution of air temperature (Ta) and relative humidity (RH) on the human thermal comfort. In this study, the discomfort index is estimated using thermal infrared data as acquired by the Advanced Very High Resolution Radiometer (AVHRR) sensor on board the National Oceanic and Atmospheric Administration (NOAA) satellite. For this purpose, a dataset of AVHRR-14 daytime images collected during the warm season from June to August 2000 covering the Greater Athens Area, in Greece, was used. Air temperature was related to a split-window estimate of land surface temperature (Ts), whereas relative humidity was assessed in terms of dew point temperature (Td) and of a split-window estimate of atmospheric precipitable water (PW). AVHRR-estimated DI values were compared with coincident DI values obtained from air temperature and relative humidity observations recorded at standard meteorological stations. Statistical analysis showed a good agreement (r2 = 0.79) between the AVHRR-estimated and the station-observed DI values, with a root mean square error (RMSE) of 1.2oC and a bias of 0.9oC. Results demonstrate the potential of using AVHRR data for defining the spatial variation of the DI index at a higher resolution (1.1 km) than is feasible from meteorological stations.

Stathopoulou, Marina I.; Cartalis, Costas; Keramitsoglou, Iphigenia; Santamouris, Matheos

2005-10-01

286

40 CFR 721.1550 - Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic acid (1:1).  

Code of Federal Regulations, 2012 CFR

...Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic...Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic...benzenediazonium, 4-(dimethylamino)-, salt with...

2012-07-01

287

40 CFR 721.1550 - Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic acid (1:1).  

Code of Federal Regulations, 2011 CFR

...Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic...Benzenediazonium, 4-(di-methyl-amino)-, salt with 2-hy-droxy-5-sul-fo-benzoic...benzenediazonium, 4-(dimethylamino)-, salt with...

2011-07-01

288

40 CFR 721.2275 - N,N,Nâ²,Nâ²-Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine.  

Code of Federal Regulations, 2010 CFR

...Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine. 721.2275 Section 721.2275 Protection of...Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine. (a) Chemical substances and significant...

2010-07-01

289

40 CFR 721.2275 - N,N,Nâ²,Nâ²-Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine.  

Code of Federal Regulations, 2010 CFR

...Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine. 721.2275 Section 721.2275 Protection of...Tetrakis(oxi-ranyl- methyl)-1,3-cyclohexane di-meth-anamine. (a) Chemical substances and significant...

2009-07-01

290

Iron–sulphur–phosphorus Interactions: Implications for Sediment Buffering Capacity in a Mediterranean Eutrophic Lagoon (Sacca di Goro, Italy)  

Microsoft Academic Search

The interactions among sedimentary cycles of sulphur, iron and phosphorus were investigated in the eutrophic Sacca di Goro lagoon (Northern Adriatic coast, Italy) in order to assess the iron buffering capacity of the sediment. Three stations were chosen, which represented different primary producer communities, hydrodynamics and sediment characteristics. Station G was close to the outlet of the Po di Volano

Roberta Azzoni; Gianmarco Giordani; Pierluigi Viaroli

2005-01-01

291

Analysis of a Borrelia burgdorferi phosphodiesterase demonstrates a role for cyclic-di-GMP in motility and virulence  

PubMed Central

Summary The genome of Borrelia burgdorferi encodes a set of genes putatively involved in cyclic-di-GMP metabolism. Although BB0419 was shown to be a diguanylate cyclase, the extent to which bb0419 or any of the putative cyclic-di-GMP metabolizing genes impact B. burgdorferi motility and pathogenesis has not yet been reported. Here we identify and characterize a phosphodiesterase (BB0363). BB0363 specifically hydrolyzed cyclic-di-GMP with a Km of 0.054 ?M, confirming it is a functional cyclic-di-GMP phosphodiesterase. A targeted mutation in bb0363 was constructed using a newly developed promoterless antibiotic cassette that does not affect downstream gene expression. The mutant cells exhibited an altered swimming pattern, indicating a function for cyclic-di-GMP in regulating B. burgdorferi motility. Furthermore, the bb0363 mutant cells were not infectious in mice, demonstrating an important role for cyclic-di-GMP in B. burgdorferi infection. The mutant cells were able to survive within Ixodes scapularis ticks after a blood meal from naïve mice; however, ticks infected with the mutant cells were not able to infect naïve mice. Both motility and infection phenotypes were restored upon genetic complementation. These results reveal an important connection between cyclic-di-GMP, B. burgdorferi motility and Lyme disease pathogenesis. A mechanism by which cyclic-di-GMP influences motility and infection is proposed.

Sultan, Syed Z.; Pitzer, Joshua E.; Miller, Michael R.; Motaleb, Md. A.

2010-01-01

292

Health hazards associated with the use of di-(2-ethylhexyl) phthalate (commonly referred to as DOP) in HEPA filter test.  

National Technical Information Service (NTIS)

Di-(2-ethylhexyl) phthalate (DEHP), commonly referred to as di-octyl phthalate, is an important production chemical in the US. In addition to its major use as an additive in plastics, DEHP is widely used to evaluate the effectiveness of high efficiency pa...

1995-01-01

293

Superheavyweight missions SI versus DI: Ascent flight design options and recommendations  

NASA Technical Reports Server (NTRS)

AFD has completed the trade study on Standard Insertion (SI) vs Direct Insertion (DI) for STS-50. RSOC Range Safety has developed acceptable DI targets from 130 n.mi. to 150 n.mi. and the corresponding performance assessment for these targets using STS-50 data has been completed. This mission has sufficient performance capability to perform this mission as a DI to 160 n.mi. A reduced OMS load corresponding to a DI mission is required for this option. The increase in altitude over the AFP baseline (SI to 145 n.mi.) is highly desirable for this mission. The orientation on orbit for the orbiter/USML-1 payload is such that orbital decay is maximized (maximum frontal cross-sectional area with vehicle normal to velocity vector). Increasing the operational altitude reduces the amount of vernier thruster firings necessary to maintain a constant gravity gradient. The results of this trade study can also be applied to other superheavyweight missions (EDO flights) and will allow for use of the DI technique for lower orbital altitudes, thereby eliminating the SI option for due east, low altitude missions. STSOC transmittal form no. 330-330-130, which documents the technical issues and assumptions used for this trade study effort in detail, should be referenced for further information. The main reason that a DI is desired for STS-50 and other superheavyweight flights (low altitude) is that ESMC range safety has expressed reservations about SI missions in general. The concern is that the current SI design underspeed exposes Africa and Madagascar to potential ET debris impact. In the past range safety has waived the requirement that these areas be protected in the event of an engine failure. With the advent of the pre-MECO OMS dump, the viability of DI and the high casualty expectations from the ACTA press to MECO hazard study, range safety has become more reluctant to approve SI flights. It is felt that to perform an SI mission there would have to be a large decrease in design underspeed to protect these landmasses, which would result in possible gaps between a late TAL and PTA. The assumed limit on a DI has been to altitudes greater than 160 n.mi. It was assumed that for altitudes less than 160 n.mi. the nominal ET impact envelope would overlap the Gilbert Islands.

1990-01-01

294

Novel tricks played by the second messenger c-di-GMP in bacterial biofilm formation  

PubMed Central

EMBO J (2013) 32 3, 354–368 doi:10.1038/emboj.2012.315; published online 09302012 The ubiquitous bacterial second messenger bis-(3?-5?)-cyclic dimeric GMP (c-di-GMP) promotes biofilm formation by an astonishing variety of molecular mechanisms. Steiner et al (2012) now report that c-di-GMP directly stimulates interaction and enzymatic activity of two subunits of the membrane-integrated machinery that produces and secretes the poly-?-1,6-N-acetylglucosamine (PGA) exopolysaccharide in Escherichia coli.

Hengge, Regine

2013-01-01

295

Spectroscopic and structural studies of di-ureasils doped with lithium perchlorate  

Microsoft Academic Search

Di-urea cross-linked POE\\/siloxane hybrid ormolytes (di-ureasils) doped with a wide concentration range of lithium perchlorate trihydrate (LiClO4·3H2O) (200?n?0.5, where n expresses the salt content in terms of the number of ether oxygen atoms per Li+ ion) have been analysed by Fourier transform infrared and Raman (FT-IR and FT-Raman, respectively) spectroscopies and X-ray diffraction (XRD). The results obtained lead us to

S. C. Nunes; V. de Zea Bermudez; D. Ostrovskii; P. B. Tavares; P. C. Barbosa; M. M. Silva; M. J. Smith

2007-01-01

296

Discrete cyclic di-GMP-dependent control of bacterial predation versus axenic growth in Bdellovibrio bacteriovorus.  

PubMed

Bdellovibrio bacteriovorus is a Delta-proteobacterium that oscillates between free-living growth and predation on Gram-negative bacteria including important pathogens of man, animals and plants. After entering the prey periplasm, killing the prey and replicating inside the prey bdelloplast, several motile B. bacteriovorus progeny cells emerge. The B. bacteriovorus HD100 genome encodes numerous proteins predicted to be involved in signalling via the secondary messenger cyclic di-GMP (c-di-GMP), which is known to affect bacterial lifestyle choices. We investigated the role of c-di-GMP signalling in B. bacteriovorus, focussing on the five GGDEF domain proteins that are predicted to function as diguanylyl cyclases initiating c-di-GMP signalling cascades. Inactivation of individual GGDEF domain genes resulted in remarkably distinct phenotypes. Deletion of dgcB (Bd0742) resulted in a predation impaired, obligately axenic mutant, while deletion of dgcC (Bd1434) resulted in the opposite, obligately predatory mutant. Deletion of dgcA (Bd0367) abolished gliding motility, producing bacteria capable of predatory invasion but unable to leave the exhausted prey. Complementation was achieved with wild type dgc genes, but not with GGAAF versions. Deletion of cdgA (Bd3125) substantially slowed predation; this was restored by wild type complementation. Deletion of dgcD (Bd3766) had no observable phenotype. In vitro assays showed that DgcA, DgcB, and DgcC were diguanylyl cyclases. CdgA lacks enzymatic activity but functions as a c-di-GMP receptor apparently in the DgcB pathway. Activity of DgcD was not detected. Deletion of DgcA strongly decreased the extractable c-di-GMP content of axenic Bdellovibrio cells. We show that c-di-GMP signalling pathways are essential for both the free-living and predatory lifestyles of B. bacteriovorus and that obligately predatory dgcC- can be made lacking a propensity to survive without predation of bacterial pathogens and thus possibly useful in anti-pathogen applications. In contrast to many studies in other bacteria, Bdellovibrio shows specificity and lack of overlap in c-di-GMP signalling pathways. PMID:22319440

Hobley, Laura; Fung, Rowena K Y; Lambert, Carey; Harris, Maximilian A T S; Dabhi, Jayesh M; King, Simon S; Basford, Sarah M; Uchida, Kaoru; Till, Robert; Ahmad, Rashidah; Aizawa, Shin-Ichi; Gomelsky, Mark; Sockett, R Elizabeth

2012-02-01

297

Metal ion complexation in acetonitrile by di-ionized calix[4]arenes bearing two dansyl fluorophores  

Microsoft Academic Search

The influence of metal cations (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Ag+, Cd2+, Co2+, Fe2+, Hg2+, Mn2+, Pb2+, Zn2+ and Fe3+) on the spectroscopic properties of two dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims of\\u000a a series of three, structurally related, di-ionized calix[4]arenes was investigated by means of absorption and emission spectrophotometry.\\u000a Di(tetramethylammonium) salts of the

Ümmühan Ocak; Miraç Ocak; Kazimierz Surowiec; Richard A. Bartsch; Maryna G. Gorbunova; Chuqiao Tu; Malgorzata A. Surowiec

2009-01-01

298

Determination of mono-, di-, and triglycerides by molecular distillation and thin-layer chromatography  

Microsoft Academic Search

Analysis of mixtures of mono-, di-, and triglycerides by molecular distillation and thin-layer chromatography is described.\\u000a \\u000a Mono- and diglycerides undergo appreciable acyl migration through the effect of heat during molecular distillation. Nevertheless\\u000a this technique may be used for the quantitative analysis of mixtures of mono-, di-, and triglycerides, provided there are\\u000a no substances present which catalyze, disproportionation.\\u000a \\u000a \\u000a \\u000a Thin-layer chromatographic (TLC)

O. S. Privett; M. L. Blank; W. O. Lundberg

1961-01-01

299

(2-tert-Butyl-3-phenyl-2,3-di-hydro-isoxazole-4,5-di-yl)bis-(phenyl-methanone).  

PubMed

The phenyl and tert-butyl groups of the title compound, C27H25NO3, exhibit a trans configuration in agreement with the stereochemistry of the Z phenyl-N-tert-butyl-nitrone starting material. The attached carbonyl groups are not coplanar with the neighboring di-hydro-isoxazole ring and the phenyl rings they are bonded to, with torsion angles of 59.26?(8), 17.53?(11), 16.52?(12) and 52.86?(7)°. The dihedral angle between the di-hydro-isoxazole ring and the directly attached phenyl group is 86.86?(8)°. There are two nonclassical inter-molecular C-H?O hydrogen-bonding inter-actions that operate together with an inter-molecular C-H?? inter-action to form a supramolecular architecture in the crystal system. PMID:24109366

Sandhya, R; Sithambaresan, M; Prathapan, S; Kurup, M R Prathapachandra

2013-01-01

300

catena-Poly[[[tetra-aqua-magnesium]-trans-?-[(piperazine-1,4-diium-1,4-di-yl)bis-(methyl-ene)]di-phospho-nato] hemihydrate  

PubMed Central

The structure of the title polymer, }[Mg(C6H14N2O6P2)(H2O)4]·0.5H2O}n, is based on centrosymmetric MgO6 octahedra, which are linked by [(piperazine-1,4-diium-1,4-di­yl)bis­(methyl­ene)]di­phospho­nate ligands, forming chains parallel to [1-1-1]. These chains are connected via hydrogen bonds primarily formed between the phospho­nate groups and water mol­ecules. The latter constitute four of the corners of the MgO6 polyhedra and bind to the O atoms of the phospho­nate groups of neighbouring chains. The lattice water molecule is disordered around an inversion centre, exhibiting an occupancy of 0.25.

Schilling, Lars-Hendrik; Stock, Norbert

2013-01-01

301

Systematic analysis of cyclic di-GMP signaling enzymes and their role in biofilm formation and virulence in Yersinia pestis  

PubMed Central

Cyclic di-GMP (c-di-GMP) is a signaling molecule that governs the transition between planktonic and biofilm states. Previously we showed that the diguanylate cyclase HmsT and the putative c-di-GMP phosphodiesterase HmsP inversely regulate biofilm formation through control of HmsHFRS-dependent poly-?-1,6-N-acetylglucosamine synthesis. Here, we systematically examine the functionality of the genes encoding putative c-di-GMP metabolic enzymes in Yersinia pestis. We determine that, in addition to hmsT and hmsP, only the gene y3730 encodes a functional enzyme capable of synthesizing c-di-GMP. The seven remaining genes are pseudogenes or encode proteins that do not function catalytically or are not expressed. Furthermore, we show that HmsP has c-di-GMP-specific phosphodiesterase activity. We report that a mutant incapable of c-di-GMP synthesis is unaffected in virulence in plague mouse models. Conversely, an hmsP mutant, unable to degrade c-di-GMP, is defective in virulence by a subcutaneous route of infection due to poly-?-1,6-N-acetylglucosamine overproduction. This suggests that c-di-GMP signaling is not only dispensable but deleterious for Y. pestis virulence. Our results show that a key event in the evolution of Y. pestis from the ancestral Yersinia pseudotuberculosis was a significant reduction in the complexity of its c-di-GMP signaling network likely resulting from the different disease cycles of these human pathogens.

Bobrov, Alexander G.; Kirillina, Olga; Ryjenkov, Dmitri A.; Waters, Christopher M.; Price, Paul A.; Fetherston, Jacqueline D.; Mack, Dietrich; Goldman, William E.; Gomelsky, Mark; Perry, Robert D.

2011-01-01

302

Bi-modal Distribution of the Second Messenger c-di-GMP Controls Cell Fate and Asymmetry during the Caulobacter Cell Cycle  

PubMed Central

Many bacteria mediate important life-style decisions by varying levels of the second messenger c-di-GMP. Behavioral transitions result from the coordination of complex cellular processes such as motility, surface adherence or the production of virulence factors and toxins. While the regulatory mechanisms responsible for these processes have been elucidated in some cases, the global pleiotropic effects of c-di-GMP are poorly understood, primarily because c-di-GMP networks are inherently complex in most bacteria. Moreover, the quantitative relationships between cellular c-di-GMP levels and c-di-GMP dependent phenotypes are largely unknown. Here, we dissect the c-di-GMP network of Caulobacter crescentus to establish a global and quantitative view of c-di-GMP dependent processes in this organism. A genetic approach that gradually reduced the number of diguanylate cyclases identified novel c-di-GMP dependent cellular processes and unraveled c-di-GMP as an essential component of C. crescentus cell polarity and its bimodal life cycle. By varying cellular c-di-GMP concentrations, we determined dose response curves for individual c-di-GMP-dependent processes. Relating these values to c-di-GMP levels modeled for single cells progressing through the cell cycle sets a quantitative frame for the successive activation of c-di-GMP dependent processes during the C. crescentus life cycle. By reconstructing a simplified c-di-GMP network in a strain devoid of c-di-GMP we defined the minimal requirements for the oscillation of c-di-GMP levels during the C. crescentus cell cycle. Finally, we show that although all c-di-GMP dependent cellular processes were qualitatively restored by artificially adjusting c-di-GMP levels with a heterologous diguanylate cyclase, much higher levels of the second messenger are required under these conditions as compared to the contribution of homologous c-di-GMP metabolizing enzymes. These experiments suggest that a common c-di-GMP pool cannot fully explain spatiotemporal regulation by c-di-GMP in C. crescentus and that individual enzymes preferentially regulate specific phenotypes during the cell cycle.

Abel, Soren; Hug, Isabelle; Kaever, Volkhard; Abel zur Wiesch, Pia; Jenal, Urs

2013-01-01

303

Character of the reaction of di- and polynucleotides with some pesticides  

Microsoft Academic Search

Lontrel, Sencor, Roundup, Kusagard, Tachigaren, Tilt, and Sethoxydim, as well as the bidentate Cu, Co, Ni, Mo, and Fe complexes of the herbicide Lontrel form molecular complexes with adenine heterocyclic compounds containing di- and polynucleotides. Sencor forms the strongest complexes, and Tilt has the lowest complexing constant. Lontrel, Sencor, Basagran, and Roundup totally destroy the cooperative character of the double

E. A. Saratovskikh; M. V. Lichina; B. L. Psikha; R. I. Gvozdev

1989-01-01

304

THE EMISSION CHARACTERISTICS OF A SMALL D.I. DIESEL ENGINE USING BIODIESEL BLENDED FUELS  

Microsoft Academic Search

Biodiesel and biodiesel blends provide low emissions without modification on the fuel system of conventional diesel engines. This study aims to develop a new domestic biodiesel production procedure which makes use of waste fryer vegetable oil by transesterification method, and further investigates the emission characteristics of a small D.I. diesel engine using biodiesel blends and diesel fuels, respectively. The 20\\/80

Yeou-Feng Lue; Yi-Yen Yeh; Chung-Hsing Wu

2001-01-01

305

Settepolesini di Bondeno (Ferrara - Eastern Po Valley): the first example of mammoth steppe in Italy  

Microsoft Academic Search

SUMMARY: Reported here is a deposit of the eastern Po Valley (Settepolesini di Bondeno - Ferrara) con- taining abundant examples of fauna from the Middle Würm, Late Glacial and Holocene (Roman Age). The excavation, carried out by a hydraulic dredge in a water bed, reaches a depth of twenty metres from the field surface. The oldest faunal association portrays, for

V. Gallini; B. Sala

306

Graft copolymers from unsaturated monomers and azo di-ester polyols and polyurethanes prepared therefrom  

US Patent & Trademark Office Database

Graft copolymers are prepared by the polymerization of an ethylenically unsaturated monomer, or a mixture of such monomers, in the presence of an azo di-ester polyol. Presence of the azo group in the polyol reactant itself serves as a free radical initiator site for the graft copolymerization reaction. The copolymers formed are utilized in the formulation of polyurethane compositions.

1982-11-16

307

[Fractionation of nucleosides and nucleoside-5'-mono-, di and triphosphates by thin layer chromatography in silufol].  

PubMed

New solvent systems--dioxane--isopropanol--water--ammonium (4:2:4:1) and dioxane--water--ammonium (6:4:1)--for rapid qualitative and quantitative estimation of nucleosides, nucleoside-5'-mono-, di- and triphosphates by thin layer chromatography is Silufol UV-254 are proposed. The Rf values for 40 ribo- and deoxyribonucleotides of these systems are given. PMID:435572

Kudelin, B K; Kaminski?, Iu L; Ivanova, I F; Gavrilin, S S

1979-02-01

308

Active coating to prolong the shelf life of Fior di latte cheese.  

PubMed

This study explains how active coating can serve to prolong the shelf life of Fior di latte cheese. The active coating was prepared by dissolving, in two sodium alginic acid solutions (5 and 8% w/v), different concentrations of lysozyme (0.25, 0.50 and 1.00 mg ml-1)+50 mm of Ethylene-Diamine Tetraacetic Acid (EDTA). Samples of Fior di latte cheese packaged in brine and active brine (lysozyme+EDTA, at the above concentrations) were also used as controls. The quality decay of the Fior di latte cheese stored at 10 degrees C was assessed by monitoring the viable cell concentration of the main spoilage microorganism, as well as its sensory quality (i.e., external appearance, consistency, colour and flavour). The concentration of rod-or coccus-shaped Lactic Acid Bacteria (LAB) was also monitored to assess the effect of the proposed packaging strategies on the flora type of Fior di latte cheese. The results show that an increase in the shelf life equal to 104% was recorded for the coated samples, compared with controls packaged in brine without active compounds. This shelf life increase is slightly lower than that recorded with samples packaged in the active brine (151%), as a result of a more pronounced microbial proliferation; however, the coating could be a better packaging solution for the reduced weight of tray. PMID:19889250

Alessandro Del Nobile, Matteo; Gammariello, Daniela; Di Giulio, Stefania; Conte, Amalia

2010-02-01

309

Genetic Modifiers of the Physical Malformations in Velo-Cardio-Facial Syndrome/DiGeorge Syndrome  

ERIC Educational Resources Information Center

Velo-cardio-facial syndrome/DiGeorge syndrome (VCFS/DGS), the most common micro-deletion disorder in humans, is characterized by craniofacial, parathyroid, and thymic defects as well as cardiac outflow tract malformations. Most patients have a similar hemizygous 3 million base pair deletion on 22q11.2. Studies in mouse have shown that "Tbx1", a…

Aggarwal, Vimla S.; Morrow, Bernice E.

2008-01-01

310

diRNA-Ago2-RAD51 complexes at double-strand break sites.  

PubMed

The way in which the DNA damage response signals the presence of DNA lesions and mediates DNA repair has not been fully elucidated. Now, Gao et al. reveal that diRNA-Ago2 complexes recruit RAD51 to the break sites. PMID:24722451

Yamanaka, Soichiro; Siomi, Haruhiko

2014-05-01

311

Spherulitic growth of single (Gd & Pr) and mixed (Di) rare earth heptamolybdates in silica gels  

Microsoft Academic Search

Single (Gd and Pr) and mixed rare earth (Di—a mixture of four rare earths La, Pr, Nd & Sm) heptamolybdates grow as platelet, multifacetted crystals and spherulites when corresponding rare earth chloride ions are made to react with ammonium paramolybdate. Various spherulitic formations are illustrated. It is shown that the spherulitic formations may be due to either fibres radially diverging

V. Hangloo; S. Pandita; K. K. Bamzai; P. N. Kotru; N. Sahni

2004-01-01

312

Delocalizzazione produttiva ad effetti territoriali complessi: il caso del Contratto di Programma Tarì Industriale  

Microsoft Academic Search

Territorial Innovation through Productive Delocalization: the Case of the Contratto di Programma Tarì Industriale in Campania - Objectives This article is a synthetic report of a one-year research aimed at evaluating the effectiveness of the CdP signed by \\

Ignazio Vinci

2008-01-01

313

Oxacalix[4]arene-supported di-, tetra- and undecanuclear copper(II) clusters.  

PubMed

Oxacalix[4]arenes containing either one or two oxa-bridges afford di and undecanuclear Cu(II) clusters respectively upon reaction with cupric nitrate under facile conditions. Variation in reaction conditions results in formation of a tetranuclear Cu(II) cluster with mono-oxacalix[4]arene, representing a structural expansion of the dinuclear assembly. PMID:24336905

Fairbairn, Robyn E; McLellan, Ross; McIntosh, Ruaraidh D; Palacios, Maria A; Brechin, Euan K; Dalgarno, Scott J

2014-04-14

314

EFFECTS OF SEWAGE SLUDGE ON DI-(2-ETHYLHEXYL) PHTHALATE UPTAKE BY PLANTS  

EPA Science Inventory

Di-(2-ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. reenhouse study was conducted to determine the effects of sludge on plant uptake of 14 C-DEHP (carbonyl labeled). lants grown included three food chain crops, lettuce (Lactuc...

315

Synthesis and characterization of DI-[3-(trimethylsilyl)-1-propylene] alkylenediphosphonic acids.  

SciTech Connect

A homologous series of alkylenediphosphonic acids was successfully esterified with 3-(trimethylsilyl)-1-propanol to the symmetrically-substituted diesters. The procedure, which has general applicability for incorporating silicon heteroatoms into diphosphonic acids, utilizes the esterification reagent dicyclohexyl-carbodiimide (DCC) to activate the acid. The aggregation properties of the di-[3-(trimethylsilyl)-1-propylene] alkylenediphosphonic acids were measured in toluene and 1-decanol.

Griffith-Dzielawa, J. A.; Barrans, R. E., Jr.; McAlister, D. R.; Dietz, M. L.; Herlinger, A. W.; Chemistry; Loyola Univ. of Chicago

2000-01-01

316

Difference gel electrophoresis (DiGE) identifies differentially expressed proteins in endoscopically-collected pancreatic fluid  

PubMed Central

Alterations in the pancreatic fluid proteome of individuals with chronic pancreatitis may offer insights into the development and progression of the disease. The endoscopic pancreas function test (ePFT) can safely collect large volumes of pancreatic fluid that are potentially amenable to proteomic analyses using difference gel electrophoresis (DiGE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pancreatic fluid was collected endoscopically using the ePFT method following secretin stimulation from three individuals with severe chronic pancreatitis and three chronic abdominal pain controls. The fluid was processed to minimize protein degradation and the protein profiles of each cohort, as determined by DiGE and LC-MS/MS, were compared. This DiGE-LC-MS/MS analysis reveals proteins that are differentially expressed in chronic pancreatitis compared to chronic abdominal pain controls. Proteins with higher abundance in pancreatic fluid from chronic pancreatitis individuals include: actin, desmoplankin, alpha-1-antitrypsin, SNC73, and serotransferrin. Those of relatively lower abundance include carboxypeptidase B, lipase, alpha-1-antichymotrypsin, alpha-2-macroglobulin, Arp2/3 subunit 4, glyceraldehyde-3-phosphate dehydrogenase, and protein disulfide isomerase. Endoscopic collection (ePFT) in tandem with DiGE-LC-MS/MS is a suitable approach for pancreatic fluid proteome analysis, however, further optimization of our protocol, as outlined herein, may improve proteome coverage in future analyses.

Paulo, Joao A.; Lee, Linda S.; Banks, Peter A.; Steen, Hanno; Conwell, Darwin L.

2012-01-01

317

A thermal lensing study of a photolysis of di- t-butyl peroxide  

NASA Astrophysics Data System (ADS)

A photolysis of di- t-butyl peroxide (BOOB) was studied by using a thermal lensing technique. This technique is found to be applicable to the determination Of the rate Constants of the decay of t-butoxy radical (BO ) and the hydrogen abstraction reaction.

Fuke, K.; Hasegawa, A.; Ueda, M.; Itoh, M.

1981-11-01

318

Effects of Injector Conditions on the Flame Lift-Off Length of DI Diesel Sprays.  

National Technical Information Service (NTIS)

The effects of injection pressure and orifice diameter on the lift-off length of a direct-injection (DI) diesel spray (defined as the farthest upstream location of high temperature combustion) were investigated using a natural light emission imaging techn...

D. L. Siebers B. S. Higgins

2000-01-01

319

The AGATA Demonstrator Array at Laboratori Nazionali di Legnaro: Status of the Project  

SciTech Connect

The AGATA Demonstrator Array is presently under installation at Laboratori Nazionali di Legnaro, Italy, where it will replace the CLARA array at the target position of the PRISMA magnetic spectrometer. In the present contribution, the details of the installation will be reviewed. Preliminary results from the first in-beam commissioning test will be given.

Farnea, E. [INFN Sezione di Padova, Padova (Italy)

2009-08-26

320

Meta-DiSc: a software for meta-analysis of test accuracy data  

PubMed Central

Background Systematic reviews and meta-analyses of test accuracy studies are increasingly being recognised as central in guiding clinical practice. However, there is currently no dedicated and comprehensive software for meta-analysis of diagnostic data. In this article, we present Meta-DiSc, a Windows-based, user-friendly, freely available (for academic use) software that we have developed, piloted, and validated to perform diagnostic meta-analysis. Results Meta-DiSc a) allows exploration of heterogeneity, with a variety of statistics including chi-square, I-squared and Spearman correlation tests, b) implements meta-regression techniques to explore the relationships between study characteristics and accuracy estimates, c) performs statistical pooling of sensitivities, specificities, likelihood ratios and diagnostic odds ratios using fixed and random effects models, both overall and in subgroups and d) produces high quality figures, including forest plots and summary receiver operating characteristic curves that can be exported for use in manuscripts for publication. All computational algorithms have been validated through comparison with different statistical tools and published meta-analyses. Meta-DiSc has a Graphical User Interface with roll-down menus, dialog boxes, and online help facilities. Conclusion Meta-DiSc is a comprehensive and dedicated test accuracy meta-analysis software. It has already been used and cited in several meta-analyses published in high-ranking journals. The software is publicly available at .

Zamora, Javier; Abraira, Victor; Muriel, Alfonso; Khan, Khalid; Coomarasamy, Arri

2006-01-01

321

SOLVENT EXTRACTION RECOVERY OF VANADIUM (AND URANIUM) FROM ACID LIQUORS WITH DI(2-ETHYLHEXYL) PHOSPHORIC ACID  

Microsoft Academic Search

Bench-scale studies were made on use of di(2ethylhexyl)-phosphoric acid ; in an organic diluent (Dapex process) for solvent extraction recovery of vanadium ; from acid leach liquors. Vanadium may be stripped from the solvent by either ; acidic or alkaline reagents, the former having been studied in considerably ; greater detail. A process for single-cycle recovery and separation of uranium

D. J. Crouse; K. B. Brown

1959-01-01

322

Method of dissolving metal oxides with di- or polyphosphonic acid and a redundant  

DOEpatents

A method of dissolving metal oxides using a mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.

Horwitz, Earl P. (Argonne, IL) [Argonne, IL; Chiarizia, Renato (Argonne, IL) [Argonne, IL

1996-01-01

323

Functional characterization of dI6 interneurons in the neonatal mouse spinal cord.  

PubMed

Our understanding of the neural control of locomotion has been greatly enhanced by the ability to identify and manipulate genetically defined populations of interneurons that comprise the locomotor central pattern generator (CPG). To date, the dI6 interneurons are one of the few populations that settle in the ventral region of the postnatal spinal cord that have not been investigated. In the present study, we utilized a novel transgenic mouse line to electrophysiologically characterize dI6 interneurons located close to the central canal and study their function during fictive locomotion. The majority of dI6 cells investigated were found to be rhythmically active during fictive locomotion and could be divided into two electrophysiologically distinct populations of interneurons. The first population fired rhythmic trains of action potentials that were loosely coupled to ventral root output and contained several intrinsic membrane properties of rhythm-generating neurons, raising the possibility that these cells may be involved in the generation of rhythmic activity in the locomotor CPG. The second population fired rhythmic trains of action potentials that were tightly coupled to ventral root output and lacked intrinsic oscillatory mechanisms, indicating that these neurons may be driven by a rhythm-generating network. Together these results indicate that dI6 neurons comprise an important component of the locomotor CPG that participate in multiple facets of motor behavior. PMID:22442567

Dyck, Jason; Lanuza, Guillermo M; Gosgnach, Simon

2012-06-01

324

The summit area (Antaeus\\/Pan di Zucchero) of the Mediterranean Ridge: a mud diapir field?  

Microsoft Academic Search

This paper presents a “state of knowledge” of the Antaeus\\/Pan di Zucchero field (the summit area of the Mediterranean Ridge) including morphological, geological, geophysical and micropaleontological data. The area is characterized by elongated elevations. The newly discovered Antaeus elevation is probably the highest point of the Mediterranean Ridge. Diapiric mud breccias have been found in two places: (1) in a

Werner Hieke; Maria B. Cita; G. Lorenzo Mirabile; Alessandra Negri; Friedrich Werner

1996-01-01

325

Accelerator-Driven Systems Neutronic Analyses at ENEA and Politecnico di Torino  

Microsoft Academic Search

A growing interest in accelerator-driven systems (ADSs) has led to the establishment in Italy of a basic research and development program aimed at the study of the physics and technological development needed to design an ADS for nuclear waste transmutation. In the framework of this program, ENEA and Politecnico di Torino are carrying out some neutronic analyses focused on an

M. Carta; K. W. Burn; A. DAngelo; V. Peluso; P. Ravetto

1999-01-01

326

MECHANISTIC CONSIDERATIONS FOR HUMAN RELEVANCE OF CANCER HAZARD OF DI(2-ETHYLHEXYL) PHTHALATE  

EPA Science Inventory

Di(2-ethylhexyl) phthalate (DEHP) is a peroxisome proliferator agent that is widely used as a plasticizer to soften polyvinylchloride plastics and non-polymers. Both occupational (e.g., by inhalation during its manufacture and use as a plasticizer of polyvinylchloride) and enviro...

327

Developmental immunotoxicity in male rats after juvenile exposure to di- n-octyltin dichloride (DOTC)  

Microsoft Academic Search

To determine relevant endpoints for evaluating developmental immunotoxicity due to juvenile exposure and optimal age of the animals at assessment, a wide range of immunological parameters were assessed in a juvenile toxicity study. Rats were exposed to di-n-octyltin dichloride (DOTC) by gavage from postnatal day (PND) 10 through PND 21 and via the diet after weaning using a benchmark dose

Elisa C. M. Tonk; Aart Verhoef; Liset J. J. de la Fonteyne; Ine D. H. Waalkens-Berendsen; André P. M. Wolterbeek; Henk van Loveren; Aldert H. Piersma

2011-01-01

328

Elastic Constants of Rare Earth and Transition Metal Di-Hydrides  

NASA Astrophysics Data System (ADS)

Determinations of the elastic constants of rare earth (RE=Er, La,) and some transition metal (TM=Sc, Ti, Zr) di-hydrides are extremely difficult. Single crystals of these di-hydrided metals can not be obtained because they break up into fine powders due to the large stresses in the materials caused by the crystallographic changes upon hydriding. However, polycrystalline thin films of these hydrided materials can be grown and are stable over a wide temperature and pressure range. In order to determine the elastic constants of thin metal di-hydride films ab-initio electronic structure calculations using the VASP code have been carried out. These calculations are then compared to bulk and shear moduli measured by a nano-indentation technique. Details and results of the calculations and measurements of the elastic constants of rare earth and transition metal di-hydride films will be presented and a discussion of future applications of this technique will be given.

Snow, C. S.; Knapp, J. A.; Browning, J. F.

2007-03-01

329

Heteroscorpionate complexes based on bis(3,5-di-tert-butylpyrazol-1-yl)dithioacetate.  

PubMed

The heteroscorpionate ligand bis(3,5-di-tert-butylpyrazol-1-yl)dithioacetate (bdtbpzdta) has been synthesized by reacting bis(3,5-di-tert-butylpyrazol-1-yl)methane with n-BuLi and CS2. The ligand was isolated as [bis(3,5-di-tert-butylpyrazol-1-yl)dithioacetato](tetrahydrofuran)lithium(I) tetrahydrofuran monosolvate, [Li(C24H39N4S2)(C4H8O)]·C4H8O or [Li(bdtbpzdta)(THF)]·THF, in which the lithium cation is bound by the ?(3)N,N',S-coordinated heteroscorpionate ligand. A similar coordination mode is observed for a zinc chloride complex bearing the bdtbpzdta ligand, namely [bis(3,5-di-tert-butylpyrazol-1-yl)dithioacetato]chloridozinc(II), [Zn(C24H39N4S2)Cl] or [Zn(bdtbpzdta)Cl], which exhibits ?(3)N,N',S-coordination and resembles the active site of zinc-containing peptide deformylases (PDFs). PMID:24005504

Tampier, Stefan; Burzlaff, Nicolai

2013-09-01

330

VITELLOGENIN GENE EXPRESSION IN MALE FATHEAD MINNOWS EXPOSED TO DI(2-ETHYLHEXYL)PHTHALATE  

EPA Science Inventory

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer used extensively in the plastics industry. DEHP has been shown to be ubiquitous in the environment and has been detected in ground and surface waters, sediment sludge and at several Superfund sites. Previous studies using rats ...

331

MONO-(3-CARBOXYPROPYL) PHTHALATE, A METABOLITE OF DI-N-OCTYL PHTHALATE  

EPA Science Inventory

Di-n-octyl phthalate (DnOP) is found as a component of mixed C6?C10 linear-chain phthalates used as plasticizers in various polyvinyl chloride applications, including flooring and carpet tiles. Following exposure and absorption, DnOP is metabolized to its hydrolytic monoester, mo...

332

Synthesis and Application of Palladium Precatalysts that Accommodate Extremely Bulky di-tert-Butylphosphino Biaryl Ligands  

PubMed Central

A series of palladacyclic precatalysts that incorporate electron-rich di-tert-butylphosphino biaryl ligands is reported. These precatalysts are easily prepared, and their use provides a general means of employing bulky ligands in palladium-catalyzed cross-coupling reactions. The application of these palladium sources to various C-N and C-O bond-forming processes is also described.

Bruno, Nicholas C.

2013-01-01

333

Dual reciprocity BEM applied to transient elastodynamic problems with diÄerential quadrature method in time  

Microsoft Academic Search

This paper is concerned with numerical analysis of the transient elastodynamic problems by the dual reciprocity BEM (DRBEM) in space combined with the diÄerential quadrature method (DQM) in time. Emphasis is placed on a comparative study of various time- marching schemes. Three numerical examples considered are for the longitudinal forced vibration of plates and the transverse free vibration of membranes.

Masataka Tanaka; Wen Chen

2001-01-01

334

I FENOMENI DI SPROFONDAMENTO: STATO DELLE CONOSCENZE ED ALCUNI ESEMPI IN ITALIA CENTRALE  

Microsoft Academic Search

RIASSUNTO Nella letteratura nazionale ed internazionale sono stati da tempo codificati numerosi termini per indicare i vari tipi di cavità che si apro- no nel terreno, attualmente però viene sempre più spesso utilizzato il termine sinkhole per definire queste forme, spesso omologhe, ma sviluppatesi attraverso processi genetici differenti. Così tale termine risulta piuttosto semplificativo e generico. Questo lavoro si propone

Stefania Nisio

335

Protection by some Carbamates against the Delayed Neurotoxic Effects of Di-isopropyl Phosphorofluoridate  

Microsoft Academic Search

ADMINISTRATION of a single dose of many organophosphorus esters to hens and other species produces a delayed neurotoxic effect characterized by a flaccid paralysis of hind limbs developing after a symptomless period of 8-14 days (for a review see ref. 1). We have studied the effect produced by di-isopropyl phosphorofluoridate (DFP) because it is a potent neurotoxic compound and does

M. K. Johnson; R. Lauwerys

1969-01-01

336

Effects of Sewage Sludge on Di- (2-Ethylhexyl) Phthalate Uptake by Plants.  

National Technical Information Service (NTIS)

Di-(2-ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. A greenhouse study was conducted to determine the effects of sludge on plant uptake of (14)C-DEHP (carbonyl labeled). Plants grown included three foo...

J. M. Aranda G. A. O'Connor G. A. Eiceman

1989-01-01

337

DEVELOPMENTAL EXPOSURE TO DI-N-BUTYLTIN DICHLORIDE (DBTC): IMMUNOTOXIC AND NEUROTOXIC EVALUATION  

EPA Science Inventory

Organotins are incorporated as stabilizers in PVC water supply pipe. Particularly when new, mono- and di-substituted methyl- and butyltins leach from the pipe and are thus of regulatory concern to EPA. These contaminants have adverse effects on both the immune and nervous systems...

338

The AGATA Demonstrator Array at Laboratori Nazionali di Legnaro: Status of the Project  

NASA Astrophysics Data System (ADS)

The AGATA Demonstrator Array is presently under installation at Laboratori Nazionali di Legnaro, Italy, where it will replace the CLARA array at the target position of the PRISMA magnetic spectrometer. In the present contribution, the details of the installation will be reviewed. Preliminary results from the first in-beam commissioning test will be given.

Farnea, E.

2009-08-01

339

Characterization of Violetto di Toscana, a typical Italian variety of artichoke ( Cynara scolymus L.)  

Microsoft Academic Search

This work regards the characterization of the phenolic compounds and the mineral composition of the variety Violetto di Toscana, which is typically cultivated in Tuscany for the flavour of its edible part. All the results achieved are compared with those of var. Terom, which is widely used in Italy. A systematic study was performed on the different plant parts: the

Annalisa Romani; Patrizia Pinelli; Claudio Cantini; Antonio Cimato; Daniela Heimler

2006-01-01

340

Plant compositions enriched in dehydrosoyasaponin I (D-I) and methods of producing such compositions  

US Patent & Trademark Office Database

There is provided a method of producing a plant composition comprising dehydrosoyasaponin I (D-I), the method comprising the steps of extracting a plant flour with a solvent capable of extracting soyasaponins to produce an extract, and treating the extract with light. Also provided are compositions produced according to the method of the present invention.

2012-08-21

341

Stimulatory actions of di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS), voltage-sensitive dye, on the BKCa channel in pituitary tumor (GH3) cells.  

PubMed

Di-8-ANEPPS (4-{2-[6-(dibutylamino)-2-naphthalenyl]-ethenyl}-1-(3-sulfopropyl)pyridinium inner salt) has been used as a fast-response voltage-sensitive styrylpyridinium probe. However, little is known regarding the mechanism of di-8-ANEPPS actions on ion currents. In this study, the effects of this dye on ion currents were investigated in pituitary GH(3) cells. In whole-cell configuration, di-8-ANEPPS (10 microM) reversibly increased the amplitude of Ca(2+)-activated K(+) current. In inside-out configuration, di-8-ANEPPS (10 microM) applied to the intracellular surface of the membrane caused no change in single-channel conductance; however, it did enhance the activity of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels with an EC(50) value of 7.5 microM. This compound caused a left shift in the activation curve of BK(Ca) channels with no change in the gating charge of these channels. A decrease in mean closed time of the channels was seen in the presence of this dye. In the cell-attached mode, di-8-ANEPPS applied on the extracellular side of the membrane also activated BK(Ca) channels. However, neither voltage-gated K(+) nor ether-à-go-go-related gene (erg)-mediated K(+) currents in GH(3) cells were affected by di-8-APPNES. Under current-clamp configuration, di-8-ANEPPS (10 microM) decreased the firing of action potentials in GH(3) cells. In pancreatic betaTC-6 cells, di-8-APPNES (10 microM) also increased BK(Ca)-channel activity. Taken together, this study suggests that during the exposure to di-8-ANEPPS, the stimulatory effects on BK(Ca) channels could be one of potential mechanisms through which it may affect cell excitability. PMID:17701422

Wu, Sheng-Nan; Lin, Ming-Wei; Wang, Ya-Jean

2008-01-01

342

Ultraviolet stimulated melanogenesis by human melanocytes is augmented by di-acyl glycerol but not TPA  

SciTech Connect

Epidermal melanocytes (MC) synthesize melanin in response to ultraviolet radiation (UVR). The mechanisms mediating the UV-induced activation of melanogenesis are unknown but since UVR induces turnover of membrane phospholipids generating prostaglandins (PGs) and other products, it is possible that one of these might provide the activating signal. We have examined the effects of prostaglandins (PGs) E1, E2, D2, F2 alpha, and di-acyl glycerol upon the UV-induced responses of cultured human MC and the Cloudman S91 melanoma cell line. The PGs had little effect on unirradiated cells and did not alter the response to UVR in either human MC or S91 melanoma cells. However, a synthetic analogue of di-acyl glycerol, 1-oleyl 2-acetyl glycerol (OAG), caused a significant (P less than 0.0001), dose-related augmentation of melanin content both in human MC (seven-fold) and S91 cells (three-fold). UVR caused a significant augmentation of the OAG-induced melanogenesis of both human MC and S91 cells. Since OAG is known to activate protein kinase C, it was possible that the observed modulation of the UVR signal could be via that pathway. Di-octanoyl glycerol, another di-acyl glycerol, which activates kinase C, caused a small (70%) increase in melanogenesis in MC which was not altered by UVR. However, 12-0 tetradecanoyl phorbol 13-acetate (TPA), a potent activator of protein kinase C, had no significant effect on either basal or UV-induced melanin synthesis in either cell type. These data suggest that the UV-induced signal activating melanogenesis could be mediated by di-acyl glycerol. Furthermore, they imply that the signal is transduced via an alternative, pathway that might be independent of protein kinase C.

Friedmann, P.S.; Wren, F.E.; Matthews, J.N. (Univ. of Newcastle upon Tyne (England))

1990-02-01

343

Analysis of tomographic mineralogical data using YaDiV—Overview and practical case study  

NASA Astrophysics Data System (ADS)

We introduce the 3D-segmentation and -visualization software YaDiV to the mineralogical application of rock texture analysis. YaDiV has been originally designed to process medical DICOM datasets. But due to software advancements and additional plugins, this open-source software can now be easily used for the fast quantitative morphological characterization of geological objects from tomographic datasets. In this paper, we give a summary of YaDiV's features and demonstrate the advantages of 3D-stereographic visualization and the accuracy of 3D-segmentation for the analysis of geological samples. For this purpose, we present a virtual and a real use case (here: experimentally crystallized and vesiculated magmatic rocks, corresponding to the composition of the 1991-1995 Unzen eruption, Japan). Especially the spacial representation of structures in YaDiV allows an immediate, intuitive understanding of the 3D-structures, which may not become clear by only looking on 2D-images. We compare our results of object number density calculations with the established classical stereological 3D-correction methods for 2D-images and show that it was possible to achieve a seriously higher quality and accuracy. The methods described in this paper are not dependent on the nature of the object. The fact, that YaDiV is open-source and users with programming skills can create new plugins themselves, may allow this platform to become applicable to a variety of geological scenarios from the analysis of textures in tiny rock samples to the interpretation of global geophysical data, as long as the data are provided in tomographic form.

Friese, Karl-Ingo; Cichy, Sarah B.; Wolter, Franz-Erich; Botcharnikov, Roman E.

2013-07-01

344

Revisiting the Anomalous Apsidal Motion of the Eccentric Eclipsing Binary DI Herculis  

NASA Astrophysics Data System (ADS)

In 1985, Guinan & Maloney presented the detailed analysis of the puzzling eclipsing binary system DI Herculis. This system is rare among main sequence stars in that its apsidal motion is dominated by the effects of General Relativity. The GR contribution to its theoretically predicted apsidal motion is 2.34 o/100 y., whereas the theoretically predicted classical contribution (due to tidal and rotational deformation of the component stars) is 1.93 o/100 y. The interesting fact is that the observed apsidal motion, determined from timings of the stars' mutual eclipses, is anomalously low: ˜1 o/100 y., well below the combined theoretical expectation of 4.27 o/100 y. Since Rudkj\\o bing's (1959) announcement of the special nature of DI Her, observers have been measuring light curves and radial velocity curves to determine the orbital parameters of the system and the stellar properties of its components. DI Her consists of two main sequence stars (B5V and B6V) in a 10.55 day eccentric orbit (e=0.489). Observations of times of minima reveal the system's apsidal motion, computed from the changing displacement of the secondary eclipse from the primary eclipse. Four decades of photoelectric measurements show that the observed apsidal motion remains below that predicted. Various explanations for this discrepancy have been offered, with the most promising involving the presence of a third component of the system. In a highly inclined orbit, the third body would diminish the rate of apsidal advance of the close pair. Adding photometry recently taken with the 0.8 m Four College Automatic Photoelectric Telescope, we present a new determination of the apsidal motion for DI Her. We also present the results from a new formalism for studying three-body interactions by Mardling in the DI Her system. This research is supported by NSF/RUI grant AST00-71260, which we gratefully acknowledge.

Maloney, F. P.; Guinan, E. F.; Barge, L. M.; Mardling, R. A.

2003-12-01

345

Gel-electrophoretic identification of hen brain neurotoxic esterase, labelled with tritiated di-isopropyl phosphorofluoridate.  

PubMed Central

The particulate fraction from hen brain was labelled with [3H]di-isopropyl phosphorofluoridate (DiPF) and separated by polyacrylamide-gel electrophoresis. Four radioactive protein bands (1--4) of molecular weights 155000, 92000, 60000, and 30000 were resolved. Most of the labelling of bands 2, 3 and 4 was inhibited by preincubation with Paraoxon. The residue in band 4 was sensitive to pH 5.2. Successive treatments with Paraoxon and pH 5.2 resulted in the abolition of bands 3 and 4. Bands 1 and 2 contained one and two polypeptides respectively, whose labelling was sensitive to Mipafox, but one, in band 2, was sensitive to higher concentrations of Paraoxon. The concentrations of the other two polypeptides were 6.7 and 1.95 pmol of DiPF bound/g of brain in bands 1 and 2 respectively. Both were as sensitive to Mipafox as neurotoxic esterase and were also sensitive to phenyl benzylcarbamate. 4-Nitrophenyl di-n-pentylphosphinate given in vivo inhibited neurotoxic esterase and the labelling of the band-1 polypeptide by 82% and 84% respectively, but inhibited the labelling of the band 2 polypeptide by 51%. The phosphinate in vitro produced 98% inhibition of the labelling of the band-1 polypeptide, with only 26% inhibition of the band-2 polypeptide, under conditions sufficient to inhibit neurotoxic esterase totally. Both neurotoxic esterase and the band-1 polypeptide were found in the forebrain at 1.74-fold their concentration in the rest of the brain, whereas the band-2 polypeptide was uniformly distributed. The evidence indicates that the Mipafox-sensitive polypeptide in band 1 is the [3H]DiPF-labelled active-site subunit of neurotoxic esterase. The catalytic-centre activity of the enzyme for phenyl valerate hydrolysis was found to be 2.6 x 10(5) min-1.

Williams, D G; Johnson, M K

1981-01-01

346

Late Quaternary tectonics of the Vallo di Diano basin (southern Apennines, Italy)  

NASA Astrophysics Data System (ADS)

We discuss new data concerning the late Quaternary tectonics of the Vallo di Diano basin, the largest intramontane depression in the southern Apennines chain (Italy). The southern Apennines axis is currently subject to NE-SW extension. Here, active NW-trending normal faults are associated with strong earthquakes ( M > 6), with average recurrence times >1 ka. The Vallo di Diano basin is a half-graben bounded by an extensional fault system VDFS (Vallo di Diano Fault System), featuring three major NW-trending, SW-dipping, ˜15-17 km long fault segments. Holocene faulting and possible historical seismicity have been documented only for the northern fault segment. No major historical earthquakes can be associated with the other fault segments, and the recent sedimentary and structural evolution of the basin is still poorly constrained. As a consequence, its seismogenetic potential has probably been underestimated. We found evidence of late Pleistocene-Holocene faulting in the relay zone of the central and southern fault segments bordering the basin. Here, late Pleistocene volcaniclastic layers at the apex of an alluvial fan are affected by normal displacements on the order of ˜1 m. Additionally, in the same area we recognized a previously unreported, 9 km long and 0.5-1.4 km wide set of scarplets (ranging in height between ˜1 m and 2.5 m) affecting late Pleistocene-late Holocene alluvial fans. The last deformation is younger than 3 ka BP. Due to the geometric arrangement of these scarplets and the long-term displacement along the Vallo di Diano Fault System, we hypothesize that the central and southern fault segments belong to a ˜32 km long hard-linked system, capable of generating Mw > 6.5 earthquakes. The Vallo di Diano basin is thus bounded to the east for its entire length (˜45 km) by an active segmented extensional fault system. Therefore it has to be considered one of the major seismogenic sources in southern Italy.

Villani, Fabio; Pierdominici, Simona

2010-11-01

347

Protection of hepatocytes against death due to mitochondrial failure: effect of di-Calciphor on antimycin A-induced toxicity.  

PubMed

Di-Calciphor is a synthetic derivative of prostaglandin B1 that protects against cerebral and cardiac ischemia apparently by preserving mitochondrial function. To determine whether di-Calciphor specifically protects against mitochondrial failure, we studied its effects on mitochondrial functions in hepatocytes treated with the specific mitochondrial poison, antimycin A. The results show that 1 microM di-Calciphor protects against cell death at concentrations of antimycin A that inhibited mitochondrial respiration and caused cellular ATP depletion. Di-Calciphor did not protect against loss of ATP but did protect against the loss of mitochondrial delta psi and delta pH. In addition, di-Calciphor protected against antimycin A-induced loading of phosphate into mitochondria and an associated mitochondrial swelling. Thus, these results show that di-Calciphor protects against a specific mitochondrial poison and support the interpretation that di-Calciphor is a mitochondrial protective agent. In addition, the results suggest that the protection of the mitochondria involves preservation of mitochondrial ionic and osmotic stability and does not involve improved ATP supply. PMID:8184430

Park, Y; Devlin, T M; Jones, D P

1994-05-01

348

Probing the activity of diguanylate cyclases and c-di-GMP phosphodiesterases in real-time by CD spectroscopy  

PubMed Central

Bacteria react to adverse environmental stimuli by clustering into organized communities called biofilms. A remarkably sophisticated control system based on the dinucleotide 3?–5? cyclic diguanylic acid (c-di-GMP) is involved in deciding whether to form or abandon biofilms. The ability of c-di-GMP to form self-intercalated dimers is also thought to play a role in this complex regulation. A great advantage in the quest of elucidating the catalytic properties of the enzymes involved in c-di-GMP turnover (diguanylate cyclases and phosphodiesterases) would come from the availability of an experimental approach for in vitro quantification of c-di-GMP in real-time. Here, we show that c-di-GMP can be detected and quantified by circular dichroism (CD) spectroscopy in the low micromolar range. The method is based on the selective ability of manganese ions to induce formation of the intercalated dimer of the c-di-GMP dinucleotide in solution, which displays an intense sigmoidal CD spectrum in the near-ultraviolet region. This characteristic spectrum originates from the stacking interaction of the four mutually intercalated guanines, as it is absent in the other cyclic dinucleotide 3?–5? cyclic adenilic acid (c-di-AMP). Thus, near-ultraviolet CD can be used to effectively quantify in real-time the activity of diguanylate cyclases and phosphodiesterases in solution.

Stelitano, Valentina; Brandt, Annegret; Fernicola, Silvia; Franceschini, Stefano; Giardina, Giorgio; Pica, Andrea; Rinaldo, Serena; Sica, Filomena; Cutruzzola, Francesca

2013-01-01

349

Cyclic di-AMP Is Critical for Listeria monocytogenes Growth, Cell Wall Homeostasis, and Establishment of Infection  

PubMed Central

ABSTRACT Listeria monocytogenes infection leads to robust induction of an innate immune signaling pathway referred to as the cytosolic surveillance pathway (CSP), characterized by expression of beta interferon (IFN-?) and coregulated genes. We previously identified the IFN-? stimulatory ligand as secreted cyclic di-AMP. Synthesis of c-di-AMP in L. monocytogenes is catalyzed by the diadenylate cyclase DacA, and multidrug resistance transporters are necessary for secretion. To identify additional bacterial factors involved in L. monocytogenes detection by the CSP, we performed a forward genetic screen for mutants that induced altered levels of IFN-?. One mutant that stimulated elevated levels of IFN-? harbored a transposon insertion in the gene lmo0052. Lmo0052, renamed here PdeA, has homology to a cyclic di-AMP phosphodiesterase, GdpP (formerly YybT), of Bacillus subtilis and is able to degrade c-di-AMP to the linear dinucleotide pApA. Reduction of c-di-AMP levels by conditional depletion of the di-adenylate cyclase DacA or overexpression of PdeA led to marked decreases in growth rates, both in vitro and in macrophages. Additionally, mutants with altered levels of c-di-AMP had different susceptibilities to peptidoglycan-targeting antibiotics, suggesting that the molecule may be involved in regulating cell wall homeostasis. During intracellular infection, increases in c-di-AMP production led to hyperactivation of the CSP. Conditional depletion of dacA also led to increased IFN-? expression and a concomitant increase in host cell pyroptosis, a result of increased bacteriolysis and subsequent bacterial DNA release. These data suggest that c-di-AMP coordinates bacterial growth, cell wall stability, and responses to stress and plays a crucial role in the establishment of bacterial infection.

Witte, Chelsea E.; Whiteley, Aaron T.; Burke, Thomas P.; Sauer, John-Demian; Portnoy, Daniel A.; Woodward, Joshua J.

2013-01-01

350

Self-assembling dicopper(II) complexes of di-2-pyridyl ketone Schiff base ligands derived from S-alkyldithiocarbazates  

Microsoft Academic Search

Condensation of di-2-pyridyl ketone with S-methyldithiocarbazate or S-benzyldithiocarbazate yields potentially bridging ligands of the form Py2CNNHC(S)SR; Hdpksme (R=Me; the di-2-pyridyl ketone Schiff base of S-methyldithiocarbazate) and Hdpksbz (R=Bz; the di-2-pyridyl ketone Schiff base of S-benzyldithiocarbazate). Complexation of these ligands with Cu(II) in a 1:1M ratio leads to the formation of dinuclear complexes of the general formula [Cu(NNNS)X]2 (X=Cl?, NO3?, H2O).

Mohammad Akbar Ali; Aminul H. Mirza; Ray J. Butcher; Paul V. Bernhardt; Mohammad Rezaul Karim

2011-01-01

351

Cellular Levels and Binding of c-di-GMP Control Subcellular Localization and Activity of the Vibrio cholerae Transcriptional Regulator VpsT  

PubMed Central

The second messenger, cyclic diguanylate (c-di-GMP), regulates diverse cellular processes in bacteria. C-di-GMP is produced by diguanylate cyclases (DGCs), degraded by phosphodiesterases (PDEs), and receptors couple c-di-GMP production to cellular responses. In many bacteria, including Vibrio cholerae, multiple DGCs and PDEs contribute to c-di-GMP signaling, and it is currently unclear whether the compartmentalization of c-di-GMP signaling components is required to mediate c-di-GMP signal transduction. In this study we show that the transcriptional regulator, VpsT, requires c-di-GMP binding for subcellular localization and activity. Only the additive deletion of five DGCs markedly decreases the localization of VpsT, while single deletions of each DGC do not impact VpsT localization. Moreover, mutations in residues required for c-di-GMP binding, c-di-GMP-stabilized dimerization and DNA binding of VpsT abrogate wild type localization and activity. VpsT does not co-localize or interact with DGCs suggesting that c-di-GMP from these DGCs diffuses to VpsT, supporting a model in which c-di-GMP acts at a distance. Furthermore, VpsT localization in a heterologous host, Escherichia coli, requires a catalytically active DGC and is enhanced by the presence of VpsT-target sequences. Our data show that c-di-GMP signaling can be executed through an additive cellular c-di-GMP level from multiple DGCs affecting the localization and activity of a c-di-GMP receptor and furthers our understanding of the mechanisms of second messenger signaling.

Shikuma, Nicholas J.; Fong, Jiunn C. N.; Yildiz, Fitnat H.

2012-01-01

352

Cellular levels and binding of c-di-GMP control subcellular localization and activity of the Vibrio cholerae transcriptional regulator VpsT.  

PubMed

The second messenger, cyclic diguanylate (c-di-GMP), regulates diverse cellular processes in bacteria. C-di-GMP is produced by diguanylate cyclases (DGCs), degraded by phosphodiesterases (PDEs), and receptors couple c-di-GMP production to cellular responses. In many bacteria, including Vibrio cholerae, multiple DGCs and PDEs contribute to c-di-GMP signaling, and it is currently unclear whether the compartmentalization of c-di-GMP signaling components is required to mediate c-di-GMP signal transduction. In this study we show that the transcriptional regulator, VpsT, requires c-di-GMP binding for subcellular localization and activity. Only the additive deletion of five DGCs markedly decreases the localization of VpsT, while single deletions of each DGC do not impact VpsT localization. Moreover, mutations in residues required for c-di-GMP binding, c-di-GMP-stabilized dimerization and DNA binding of VpsT abrogate wild type localization and activity. VpsT does not co-localize or interact with DGCs suggesting that c-di-GMP from these DGCs diffuses to VpsT, supporting a model in which c-di-GMP acts at a distance. Furthermore, VpsT localization in a heterologous host, Escherichia coli, requires a catalytically active DGC and is enhanced by the presence of VpsT-target sequences. Our data show that c-di-GMP signaling can be executed through an additive cellular c-di-GMP level from multiple DGCs affecting the localization and activity of a c-di-GMP receptor and furthers our understanding of the mechanisms of second messenger signaling. PMID:22654664

Shikuma, Nicholas J; Fong, Jiunn C N; Yildiz, Fitnat H

2012-01-01

353

Utero-vaginal aplasia (Mayer-Rokitansky-K?ster-Hauser syndrome) associated with deletions in known DiGeorge or DiGeorge-like loci  

PubMed Central

Background Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by congenital aplasia of the uterus and the upper part of the vagina in women showing normal development of secondary sexual characteristics and a normal 46, XX karyotype. The uterovaginal aplasia is either isolated (type I) or more frequently associated with other malformations (type II or Müllerian Renal Cervico-thoracic Somite (MURCS) association), some of which belong to the malformation spectrum of DiGeorge phenotype (DGS). Its etiology remains poorly understood. Thus the phenotypic manifestations of MRKH and DGS overlap suggesting a possible genetic link. This would potentially have clinical consequences. Methods We searched DiGeorge critical chromosomal regions for chromosomal anomalies in a cohort of 57 subjects with uterovaginal aplasia (55 women and 2 aborted fetuses). For this candidate locus approach, we used a multiplex ligation-dependent probe amplification (MLPA) assay based on a kit designed for investigation of the chromosomal regions known to be involved in DGS. The deletions detected were validated by Duplex PCR/liquid chromatography (DP/LC) and/or array-CGH analysis. Results We found deletions in four probands within the four chromosomal loci 4q34-qter, 8p23.1, 10p14 and 22q11.2 implicated in almost all cases of DGS syndrome. Conclusion Uterovaginal aplasia appears to be an additional feature of the broad spectrum of the DGS phenotype. The DiGeorge critical chromosomal regions may be candidate loci for a subset of MRKH syndrome (MURCS association) individuals. However, the genes mapping at the sites of these deletions involved in uterovaginal anomalies remain to be determined. These findings have consequences for clinical investigations, the care of patients and their relatives, and genetic counseling.

2011-01-01

354

Convegno. Medicina narrativa e malattie rare. Istituto Superiore di Sanita. Roma, 26 giugno 2009. (Meeting. Narrative Medicine and Rare Diseases. Istituto Superiore di Sanita. Rome, June 26, 2009. Proceedings).  

National Technical Information Service (NTIS)

Narrative medicine and rare diseases has been the first congress on these topics in Italy, organized by the National Centre for Rare Diseases at the Istituto Superiore di Sanita (Italian National Institute of Health); the congress aimed to promote narrati...

A. E. Gentile D. Taruscio I. Luzi S. Razeto

2009-01-01

355

Personale Femminile e Carriere delle Ricercatrici dell'Istituto Superiore di Sanita. Primo Rapporto. (Women's Presence and Careers of Female Researchers of the Istituto Superiore di Sanita. First Report.)  

National Technical Information Service (NTIS)

This report is a gender-oriented description of the human resources of the Istituto Superiore di Sanita (Italian National Institute of Health), and focuses on women's careers and incidence in research managerial bodies. The analysis accounts for several f...

M. Torre G. Calamandrei M. Orlando

2002-01-01

356

Relazione dell'Istituto Superiore di Sanita sui Risultati dell'Attivita Svolta nel 2005. (Report of the Istituto Superiore di Sanita on the Activities Carried Out in 2005.)  

National Technical Information Service (NTIS)

The document contains an overview of the present structure and rules of the Istituto Superiore di Sanita (ISS, the Italian National Institute of Health). A brief report of its research, control, prevention, advice and training activities is given for each...

2006-01-01

357

THE STATE OF MANGANESE IN THE PHOTOSYNTHETIC APPARATUS. I. EXAFS STUDIES ON CHLOROPLASTS AND di-u-oxo BRIDGED di-MANGANESE MODEL COMPOUNDS  

SciTech Connect

Extended X-ray Absorption Fine Structure (EXAFS) studies on the manganese contained in spinach chloroplasts and on certain di-u-oxo bridged manganese dimers of the form (X{sub 2}Mn)O{sub 2}(MnX{sub 2} (X=2,2'-bypyridine and 1,10-phenanthroline) are reported. From these studies, the manganese associated with photosynthetic oxygen evolution is suggested to occur as a bridged transition metal dimer with most likely another manganese. Extensive details on the analysis are included.

Kirby, J.A.; Robertson, A.S.; Smith, J.P.; Thompson, A.C.; Thompson, A.C.; Klein, M.P.

1980-11-01

358

Bis(?2-di-phenyl-phosphinamide-?2 O:O)bis-[bis(di-phenyl-phosphinamide-?O)lithium] dichloride aceto-nitrile disolvate  

PubMed Central

The asymmetric unit of the title compound, [Li2(C12H12NOP)6]Cl2·2CH3CN, contains one-half of the centrosymmetric dication, one chloride anion and one aceto­nitrile solvent mol­ecule. Each Li atom is coordinated by four O atoms [Li—O 1.891?(3) and 2.025?(3)?Å] from the four di­phenyl­phosphinamide ligands in a distorted tetra­hedral geometry. In the crystal, weak N—H?Cl hydrogen bonds link the anions and dications into columns extending along [100].

Li, Ai-Hong; Han, Jun-Ping; Li, Jing

2014-01-01

359

[N,N?-Bis(2,6-diethyl-4-phenyl-phen-yl)butane-2,3-di-imine-?2 N,N?]di-bromido-nickel(II)  

PubMed Central

The complex molecule in the title compound, [NiBr2(C36H40N2)], has mirror symmetry. The NiII atom and two Br atoms are located on the mirror plane. The NiII atom is four-coordinated by the two Br atoms and two N atoms from an N,N?-bis(2,6-diethyl-4-phenyl­phen­yl)butane-2,3-di­imine ligand in a distorted tetra­hedral geometry. The dihedral angle formed between the two adjacent benzene rings is 47.1?(1)°.

Yuan, Jianchao; Xia, Jingjing; Xu, Weibing; Mu, Yanqiong

2014-01-01

360

Bis(?2-di-phenyl-phosphinamide-?(2) O:O)bis-[bis(di-phenyl-phosphinamide-?O)lithium] dichloride aceto-nitrile disolvate.  

PubMed

The asymmetric unit of the title compound, [Li2(C12H12NOP)6]Cl2·2CH3CN, contains one-half of the centrosymmetric dication, one chloride anion and one aceto-nitrile solvent mol-ecule. Each Li atom is coordinated by four O atoms [Li-O 1.891?(3) and 2.025?(3)?Å] from the four di-phenyl-phosphinamide ligands in a distorted tetra-hedral geometry. In the crystal, weak N-H?Cl hydrogen bonds link the anions and dications into columns extending along [100]. PMID:24940208

Li, Ai-Hong; Han, Jun-Ping; Li, Jing

2014-06-01

361

Atomistic Study of the Migration of Di- and Tri-Interstitials in Silicon  

SciTech Connect

A comprehensive study on the migration of di- and tri-interstitials in silicon is performed using classical molecular dynamics simulations with a Stillinger-Weber potential. At first the structures and energetics of the di- and the tri-interstitial are investigated, and the accuracy of the interatomic potential is tested by comparing the results with literature data obtained by tight-binding and density-functional-theory calculations. Then the migration is investigated for temperatures between 800 and 1600 K. Very long simulation times, large computational cells and different initial conditions are considered. The defect diffusivity, the self-diffusion coefficient per defect and the corresponding effective migration barriers are calculated. Compared to a mono-interstitial, the di-interstitial migrates faster, whereas the tri-interstitial diffuses slower. The mobility of the di- and the mono-interstitial is higher than the mobility of the lattice atoms during the diffusion of these defects. On the other hand, the tri-interstitial mobility is lower than the corresponding atomic mobility. The migration mechanism of the di-interstitial shows a pronounced dependence on the temperature. At low temperature a high mobility on zigzag-like lines along a <110> axis within a {l_brace}110{r_brace} plane is found, whereas the change between equivalent <110> directions or equivalent {l_brace}110{r_brace} planes occurs seldomly and requires a long simulation time, but the rate of directional change increases with increasing temperature. During the diffusion within {l_brace}110{r_brace} planes the di-interstitial moves like a wave packet so that the atomic mobility is lower than that of the defect. On the other hand, the change between equivalent {l_brace}110{r_brace} migration planes is characterized by frequent atomic rearrangements. The visual analysis of the tri-interstitial diffusion reveals complex migration mechanisms and a high atomic mobility. The diffusivities and effective migration barriers obtained are compared with the few data from the literature. The implications of the present results for the explanation of experimental data on defect evolution and migration are discussed.

Posselt, Matthias; Gao, Fei; Zwicker, D

2005-06-22

362

Cyclic di-GMP is Essential for the Survival of the Lyme Disease Spirochete in Ticks  

PubMed Central

Cyclic dimeric GMP (c-di-GMP) is a bacterial second messenger that modulates many biological processes. Although its role in bacterial pathogenesis during mammalian infection has been documented, the role of c-di-GMP in a pathogen's life cycle within a vector host is less understood. The enzootic cycle of the Lyme disease pathogen Borrelia burgdorferi involves both a mammalian host and an Ixodes tick vector. The B. burgdorferi genome encodes a single copy of the diguanylate cyclase gene (rrp1), which is responsible for c-di-GMP synthesis. To determine the role of c-di-GMP in the life cycle of B. burgdorferi, an Rrp1-deficient B. burgdorferi strain was generated. The rrp1 mutant remains infectious in the mammalian host but cannot survive in the tick vector. Microarray analyses revealed that expression of a four-gene operon involved in glycerol transport and metabolism, bb0240-bb0243, was significantly downregulated by abrogation of Rrp1. In vitro, the rrp1 mutant is impaired in growth in the media containing glycerol as the carbon source (BSK-glycerol). To determine the contribution of the glycerol metabolic pathway to the rrp1 mutant phenotype, a glp mutant, in which the entire bb0240-bb0243 operon is not expressed, was generated. Similar to the rrp1 mutant, the glp mutant has a growth defect in BSK-glycerol medium. In vivo, the glp mutant is also infectious in mice but has reduced survival in ticks. Constitutive expression of the bb0240-bb0243 operon in the rrp1 mutant fully rescues the growth defect in BSK-glycerol medium and partially restores survival of the rrp1 mutant in ticks. Thus, c-di-GMP appears to govern a catabolic switch in B. burgdorferi and plays a vital role in the tick part of the spirochetal enzootic cycle. This work provides the first evidence that c-di-GMP is essential for a pathogen's survival in its vector host.

He, Ming; Ouyang, Zhiming; Troxell, Bryan; Xu, Haijun; Moh, Akira; Piesman, Joseph; Norgard, Michael V.; Gomelsky, Mark; Yang, X. Frank

2011-01-01

363

Central radio galaxies in groups: cavities, bubbles and the history of AGN heating  

NASA Astrophysics Data System (ADS)

E' noto che le regioni centrali degli ammassi e gruppi di galassie costituiscono un ambiente in cui gas caldo e plasma radioemittente proveniente dalle galassie dominanti interagiscono tra loro. In particolare, si pensa che la radioemissione dell'AGN centrale ed i suoi possibili cicli di attivita', siano strettamente legati alla presenza di cavita' e "bubbles" nel gas intergalattico. Si presentera' lo status di un progetto osservativo effettuato con il Giant Metrewave Radio Telescope (GMRT, India) su di un campione di 18 gruppi di galassie, osservati a tre frequenze radio (235 MHz, 325 MHz e 610 MHz). Lo studio della morfologia radio degli AGN centrali e la relativa analisi spettrale permettono di ottenere stime sull'eta' di questi oggetti, e sulla loro energia totale, che a loro volta sono in relazione con le proprieta' X dei gruppi stessi. Per tutti gli oggetti del campione sono disponibili osservazioni Chandra di proprieta'. Per due oggetti del campione, 4C+24.36 (al centro di AWM04) e NGC741 (al centro di RSOG17) verra' presentato uno studio dettagliato.

Giacintucci, S.; Venturi, T.; Raychaudhury, S.; Vrtilek, J.

2008-10-01

364

An investigation into the molecular stability of zinc di-alkyl-di-thiophosphates (ZDDPs) in relation to their use as anti-wear and anti-corrosion additives in lubricating oils  

Microsoft Academic Search

The electronic energies and structures of the monomeric, neutral and basic forms of the important lubricating oil additive zinc di-alkyl-di-thiophosphate (ZDDP) are examined by molecular optimisation techniques using semi-empirical quantum chemistry calculations (MNDO). The optimised geometries reveal good agreement with known crystallographic data. The molecular stability is found to be highest for the basic form of ZDDP. For all forms,

D. R Armstrong; E. S Ferrari; K. J Roberts; D Adams

1997-01-01

365

An X-ray absorption spectroscopy examination of structural changes to zinc di-alkyl-di-thiophosphate (ZDDP) following milling in the presence of iron oxides and subsequent thermal processing  

Microsoft Academic Search

Solid-state mixtures of the lubricating oil additive zinc di-alkyl-di-thiophosphate (ZDDP) with two different iron oxide phases (FeO and Fe2O3) prepared by milling are examined using X-ray absorption spectroscopy (EXAFS). The changes of the local atomic environment around the zinc atomic site within ZDDP, both in the presence of iron and following subsequent temperature profiling, are discussed. The thermal decomposition behaviour

E. S Ferrari; K. J Roberts; D Adams

2002-01-01

366

Oxidation of 2,6-di-tert-butyl-4-methylphenol. The structure of C14H22O3  

USGS Publications Warehouse

The acidic compound C14H22O3, previously reported without assignment of structure as an oxidation product of 2,6-di-tert-butyl-4-methylphenol, is now believed to be DL-trans-5,6-di-tert-butyl-2-hydroxy-1,4-diketo-2-cyclohexene (I). Chemical properties are described and infrared spectra are presented in support of this structure. This structure is of interest in relation to the problem of the existence of o-di-tert-alkylbenzene derivatives. The relatively easy racemization of optically active I suggests that its completely enolized form, 5,6-di-tert-butyl-1,2,4-trihydroxybenzene, is capable of transitory existence.

Yohe, G. R.; Dunbar, J. E.; Lansford, M. W.; Pedrotti, R. L.; Scheidt, F. M.; Lee, F. G. H.; Smith, E. C.

1959-01-01

367

Vibrio cholerae VpsT regulates matrix production and motility by directly sensing cyclic di-GMP*  

PubMed Central

Microorganisms can switch from a planktonic, free-swimming life style to a sessile, colonial state, called a biofilm, conferring resistance to environmental stress. Conversion between the motile and biofilm life style has been attributed to increased levels of the prokaryotic second messenger cyclic di-guanosine monophosphate (c-di-GMP), yet the signaling mechanisms mediating such a global switch are poorly understood. Here we show that the transcriptional regulator VpsT from Vibrio cholerae directly senses c-di-GMP to inversely control extracellular matrix production and motility, identifying VpsT as a master regulator for biofilm formation. Rather than being regulated by phosphorylation, VpsT undergoes a change in oligomerization upon c-di-GMP binding.

Krasteva, Petya V.; Fong, Jiunn C.N.; Shikuma, Nicholas J.; Beyhan, Sinem; Navarro, Marcos V.A.S.; Yildiz, Fitnat H.; Sondermann, Holger

2010-01-01

368

Vibrio cholerae VpsT regulates matrix production and motility by directly sensing cyclic di-GMP.  

PubMed

Microorganisms can switch from a planktonic, free-swimming life-style to a sessile, colonial state, called a biofilm, which confers resistance to environmental stress. Conversion between the motile and biofilm life-styles has been attributed to increased levels of the prokaryotic second messenger cyclic di-guanosine monophosphate (c-di-GMP), yet the signaling mechanisms mediating such a global switch are poorly understood. Here we show that the transcriptional regulator VpsT from Vibrio cholerae directly senses c-di-GMP to inversely control extracellular matrix production and motility, which identifies VpsT as a master regulator for biofilm formation. Rather than being regulated by phosphorylation, VpsT undergoes a change in oligomerization on c-di-GMP binding. PMID:20150502

Krasteva, Petya V; Fong, Jiunn C N; Shikuma, Nicholas J; Beyhan, Sinem; Navarro, Marcos V A S; Yildiz, Fitnat H; Sondermann, Holger

2010-02-12

369

Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono, Di and Trihalogenated DBPs - SLIDES  

EPA Science Inventory

Examination of bromine incorporation in emerging DBPs vs that of regulated DBPs Study of predominance of di- vs trihalogenated species in different DBP classes Better understand and characterize exposure to DBPs of health concern...

370

Indagine sull'attivita di Procreazione Medicalmente Assistita in Italia (Survey of Assisted Reproductive Activity in Italy).  

National Technical Information Service (NTIS)

In 2001, the Italian Minister of Health asked an appointed Working Group of clinicians and some epidemiologists of the Istituto Superiore di Sanita (ISS, the Italian National Institute of Health) to conduct a survey on the activities of Assisted Reproduct...

A. Spinelli G. Scaravelli V. Vigiliano S. Diemoz

2003-01-01

371

Inactivation of Cyclic Di-GMP Binding Protein TDE0214 Affects the Motility, Biofilm Formation, and Virulence of Treponema denticola  

PubMed Central

As a ubiquitous second messenger, cyclic dimeric GMP (c-di-GMP) has been studied in numerous bacteria. The oral spirochete Treponema denticola, a periodontal pathogen associated with human periodontitis, has a complex c-di-GMP signaling network. However, its function remains unexplored. In this report, a PilZ-like c-di-GMP binding protein (TDE0214) was studied to investigate the role of c-di-GMP in the spirochete. TDE0214 harbors a PilZ domain with two signature motifs: RXXXR and DXSXXG. Biochemical studies showed that TDE0214 binds c-di-GMP in a specific manner, with a dissociation constant (Kd) value of 1.73 ?M, which is in the low range compared to those of other reported c-di-GMP binding proteins. To reveal the role of c-di-GMP in T. denticola, a TDE0214 deletion mutant (Td?214) was constructed and analyzed in detail. First, swim plate and single-cell tracking analyses showed that Td?214 had abnormal swimming behaviors: the mutant was less motile and reversed more frequently than the wild type. Second, we found that biofilm formation of Td?214 was substantially repressed (?6.0-fold reduction). Finally, in vivo studies using a mouse skin abscess model revealed that the invasiveness and ability to induce skin abscesses and host humoral immune responses were significantly attenuated in Td?214, indicative of the impact that TDE0214 has on the virulence of T. denticola. Collectively, the results reported here indicate that TDE0214 plays important roles in motility, biofilm formation, and virulence of the spirochete. This report also paves a way to further unveil the roles of the c-di-GMP signaling network in the biology and pathogenicity of T. denticola.

Bian, Jiang; Liu, Xiangyang; Cheng, Yi-Qiang

2013-01-01

372

Vibrio cholerae VpsT Regulates Matrix Production and Motility by Directly Sensing Cyclic di-GMP  

Microsoft Academic Search

Microorganisms can switch from a planktonic, free-swimming life-style to a sessile, colonial state, called a biofilm, which confers resistance to environmental stress. Conversion between the motile and biofilm life-styles has been attributed to increased levels of the prokaryotic second messenger cyclic di-guanosine monophosphate (c-di-GMP), yet the signaling mechanisms mediating such a global switch are poorly understood. Here we show that

Petya V. Krasteva; Jiunn C. N. Fong; Nicholas J. Shikuma; Sinem Beyhan; Marcos V. A. S. Navarro; Fitnat H. Yildiz; Holger Sondermann

2010-01-01

373

Complex c-di-GMP Signaling Networks Mediate Transition between Virulence Properties and Biofilm Formation in Salmonella enterica Serovar Typhimurium  

PubMed Central

Upon Salmonella enterica serovar Typhimurium infection of the gut, an early line of defense is the gastrointestinal epithelium which senses the pathogen and intrusion along the epithelial barrier is one of the first events towards disease. Recently, we showed that high intracellular amounts of the secondary messenger c-di-GMP in S. typhimurium inhibited invasion and abolished induction of a pro-inflammatory immune response in the colonic epithelial cell line HT-29 suggesting regulation of transition between biofilm formation and virulence by c-di-GMP in the intestine. Here we show that highly complex c-di-GMP signaling networks consisting of distinct groups of c-di-GMP synthesizing and degrading proteins modulate the virulence phenotypes invasion, IL-8 production and in vivo colonization in the streptomycin-treated mouse model implying a spatial and timely modulation of virulence properties in S. typhimurium by c-di-GMP signaling. Inhibition of the invasion and IL-8 induction phenotype by c-di-GMP (partially) requires the major biofilm activator CsgD and/or BcsA, the synthase for the extracellular matrix component cellulose. Inhibition of the invasion phenotype is associated with inhibition of secretion of the type three secretion system effector protein SipA, which requires c-di-GMP metabolizing proteins, but not their catalytic activity. Our findings show that c-di-GMP signaling is at least equally important in the regulation of Salmonella-host interaction as in the regulation of biofilm formation at ambient temperature.

Le Guyon, Soazig; Streck, Elena; Barthel, Melanie; Peters, Verena; Hardt, Wolf-Dieter; Romling, Ute

2011-01-01

374

c-di-GMP Turn-Over in Clostridium difficile Is Controlled by a Plethora of Diguanylate Cyclases and Phosphodiesterases  

Microsoft Academic Search

Clostridium difficile infections have become a major healthcare concern in the last decade during which the emergence of new strains has underscored this bacterium's capacity to cause persistent epidemics. c-di-GMP is a bacterial second messenger regulating diverse bacterial phenotypes, notably motility and biofilm formation, in proteobacteria such as Vibrio cholerae, Pseudomonas aeruginosa, and Salmonella. c-di-GMP is synthesized by diguanylate cyclases

Eric Bordeleau; Louis-Charles Fortier; François Malouin; Vincent Burrus

2011-01-01

375

SO2Cl2, SOCl2: energy dispersive X-ray diÄraction, ab initio and molecular dynamics calculation  

Microsoft Academic Search

This work reports a new protocol for achieving microscopic structural information from theoretical (quantum- chemical (QC) and molecular dynamic (MD) calculations) and experimental methods (X-ray diÄraction). The Lennard- Jones (L-J) parameters of the force field (FF) fit satisfactorily the X-ray diÄraction results of the liquid samples. The study has been carried out on SOCl2 and SO2Cl2 molecular liquids. \\

S. Meloni; A. Pieretti; L. Bencivenni; V. Rossi Albertini; C. Sadun; R. Caminiti

2001-01-01

376

1-(3,5-Di-meth-oxy-phen-yl)-4,5-dimethyl-2-phenyl-1H-imidazole  

PubMed Central

In the title mol­ecule, C19H20N2O2, the imidazole ring makes dihedral angles of 57.29?(5) and 31.54?(5)° with the attached di­meth­oxy­phenyl residue and the phenyl ring, respectively. The dihedral angle between the di­meth­oxy­phenyl and phenyl rings is 61.15?(5)°. In the crystal, pairs of C—H?N hydrogen bonds connect the mol­ecules into inversion dimers.

Divya, G.; Saravanan, K.; Santhiya, S.; Chandralekha, K.; Lakshmi, S.

2013-01-01

377

Inter-population diVerences in the tolerance of a marsupial folivore to plant secondary metabolites  

Microsoft Academic Search

Plant secondary metabolites (PSMs) strongly inXuence diet selection by mammalian herbivores. Concen- trations of PSMs vary within and among plant species, and across landscapes. Therefore, local adaptations may cause diVerent populations of herbivores to diVer in their ability to tolerate PSMs. Here, we tested the food intake responses of three populations of a marsupial folivore, the common brushtail possum (Trichosurus

Jane L. DeGabriel; Ben D. Moore; Lisa A. Shipley; Andrew K. Krockenberger; Ian R. Wallis; Christopher N. Johnson; William J. Foley

378

The c-di-GMP recognition mechanism of the PilZ domain of bacterial cellulose synthase subunit A.  

PubMed

In some Proteobacteria and Firmicutes such as Pseudomonas aeruginosa, Vibrio cholerae, Xanthomonas campestris, and Clostridium difficile, cyclic dimeric guanosine monophosphate (c-di-GMP) is known to regulate cellular processes, including motility, biofilm formation, and virulence, as a second messenger. Cellulose production in Acetobacter xylinum, a model organism of cellulose biosynthesis, also depends on by cellular c-di-GMP level. In cellulose-synthesizing bacteria, a terminal complex localized in the cell membrane synthesizes cellulose and regulates the production of cellulose sensed by c-di-GMP. Although previous studies indicated that the PilZ domain conserved in cellulose synthase subunit A (CeSA) was part of a receptor for c-di-GMP, the recognition mechanism by PilZ domain of CeSA remains unclear. In the present study, we studied the interaction between c-di-GMP and the PilZ domain of CeSA from a structural viewpoint. First, we solved the crystal structure of the PilZ domain of CeSA from A. xylinum (AxCeSA-PilZ) at 2.1Å resolution. Then, comparison of the sequence and structure of AxCeSA-PilZ to those of known structures of PilZ, such as VCA0042, PP4397, and PA4608, indicated the involvement of Lys573 and Arg643 of AxCeSA-PilZ in the recognition of c-di-GMP besides the RxxxR motif. Finally, the binding characteristics of c-di-GMP to AxCeSA-PilZ and mutants were determined with isothermal titration calorimetry, indicating that the residues corresponding to Lys573 and Arg643 in AxCeSA-PilZ generally contribute to the binding of c-di-GMP to PilZ. PMID:23291177

Fujiwara, Takaaki; Komoda, Keisuke; Sakurai, Naofumi; Tajima, Kenji; Tanaka, Isao; Yao, Min

2013-02-22

379

Diisobutyl phthalate has comparable anti-androgenic effects to di- n-butyl phthalate in fetal rat testis  

Microsoft Academic Search

Phthalates are widely used as plasticizers in various consumer products and building materials. Some of the phthalates are known to interfere with male reproductive development in rats, and di-n-butyl phthalate (DBP), diethylhexyl phthalate (DEHP) and butyl benzyl phthalate (BBP) were recently banned for use in toys in the EU mainly due to their reproductive toxicity. Diisobutyl phthalate (DiBP) has similar

Julie Borch; Marta Axelstad; Anne Marie Vinggaard; Majken Dalgaard

2006-01-01

380

Negative magnetoresistance and spin filtering of spin-coupled di-iron-oxo clusters  

NASA Astrophysics Data System (ADS)

Spin-dependent transport has been computationally studied for an open-shell singlet di-iron-oxo cluster. Currents and magnetoresistances have been investigated as a function of spin state within the nonequilibrium Green's function approach. The applied bias can be used to tune the sign of the observed magnetoresistance. A colossal magnetoresistance has been determined for hydrogen anchoring. Applied biases lower than 0.3 V, in conjunction with sulfur anchoring, induce a negative magnetoresistance due to lowering of the anchor-scatterer tunneling barrier. The di-iron-oxo cluster displays nearly perfect spin filtering for parallel alignment of the iron magnetic moments due to the energetic proximity, relative to the Fermi level, of its highest occupied molecular orbitals.

Wang, Rui-Ning; Rodriguez, Jorge H.; Liu, Wu-Ming

2014-06-01

381

Simulating water, solute, and heat transport in the subsurface with the VS2DI software package  

USGS Publications Warehouse

The software package VS2DI was developed by the U.S. Geological Survey for simulating water, solute, and heat transport in variably saturated porous media. The package consists of a graphical preprocessor to facilitate construction of a simulation, a postprocessor for visualizing simulation results, and two numerical models that solve for flow and solute transport (VS2DT) and flow and heat transport (VS2DH). The finite-difference method is used to solve the Richards equation for flow and the advection-dispersion equation for solute or heat transport. This study presents a brief description of the VS2DI package, an overview of the various types of problems that have been addressed with the package, and an analysis of the advantages and limitations of the package. A review of other models and modeling approaches for studying water, solute, and heat transport also is provided. ?? Soil Science Society of America. All rights reserved.

Healy, R. W.

2008-01-01

382

Deubiquitinating Enzyme Specificity for Ubiquitin Chain Topology Profiled by Di-Ubiquitin Activity Probes  

PubMed Central

Summary Posttranslational modification with ubiquitin (Ub) controls many cellular processes, and aberrant ubiquitination can contribute to cancer, immunopathology, and neurodegeneration. The versatility arises from the ability of Ub to form polymer chains with eight distinct linkages via lysine side chains and the N terminus. In this study, we engineered Di-Ub probes mimicking all eight different poly-Ub linkages and profiled the deubiquitinating enzyme (DUB) selectivity for recognizing Di-Ub moieties in cellular extracts. Mass spectrometric profiling revealed that most DUBs examined have broad selectivity, whereas a subset displays a clear preference for recognizing noncanonical over K48/K63 Ub linkages. Our results expand knowledge of Ub processing enzyme functions in cellular contexts that currently depends largely on using recombinant enzymes and substrates.

McGouran, Joanna F.; Gaertner, Selina R.; Altun, Mikael; Kramer, Holger B.; Kessler, Benedikt M.

2013-01-01

383

Deubiquitinating enzyme specificity for ubiquitin chain topology profiled by di-ubiquitin activity probes.  

PubMed

Posttranslational modification with ubiquitin (Ub) controls many cellular processes, and aberrant ubiquitination can contribute to cancer, immunopathology, and neurodegeneration. The versatility arises from the ability of Ub to form polymer chains with eight distinct linkages via lysine side chains and the N terminus. In this study, we engineered Di-Ub probes mimicking all eight different poly-Ub linkages and profiled the deubiquitinating enzyme (DUB) selectivity for recognizing Di-Ub moieties in cellular extracts. Mass spectrometric profiling revealed that most DUBs examined have broad selectivity, whereas a subset displays a clear preference for recognizing noncanonical over K48/K63 Ub linkages. Our results expand knowledge of Ub processing enzyme functions in cellular contexts that currently depends largely on using recombinant enzymes and substrates. PMID:24290882

McGouran, Joanna F; Gaertner, Selina R; Altun, Mikael; Kramer, Holger B; Kessler, Benedikt M

2013-12-19

384

New solid-state sensing materials for gaseous dimethylcadmium, di- iso-propyltelluride and dimethylmercury  

NASA Astrophysics Data System (ADS)

Simple solid-state colorimetric sensors for precursors used in and toxic by-products of metal organic vapour-phase epitaxy (MOVPE) of mercury cadmium telluride (MCT) are described. 2,2'-Bipyridine and its commercially available 4,4'-dimethyl-, 5,5'-dimethyl- and 4,4'-di- tert-butyl-dialkyl derivatives have been found to change colour from white or off-white to yellow in the presence of dimethylcadmium at concentrations as low as 13 ppm. The red form of mercury(II) iodide has been tested in both hydrogen and helium gas streams and found to change colour to yellow or white in the presence of gaseous di- iso-propyltelluride at concentrations as low as 1.5 ppm. This form of mercury(II) iodide also reacts photochemically with Me 2Hg in a helium or hydrogen gas stream down to a concentration of 37 ppm.

Pardoe, Jennifer A. J.; Cole-Hamilton, David. J.; Hails, Janet E.

2005-01-01

385

First principle evaluation of the chiroptical activity of the di-phenyl-diazene derivatives  

NASA Astrophysics Data System (ADS)

Azobenzene (di-phenyl-diazene) is well-known as a photoisomerisable molecule and has been widely studied as a molecular photoswitcher. Molecular rods, where di-phenyl arms are bound to the diazene moiety, have been also synthesized. In this article we explore by first principle density functional theory calculations the chiroptical properties (electronic circular dichroism spectra, ECD) of azobenzene and its homologues with polyphenyl arms. In particular, we demonstrate that for molecules in the cis configuration the intrinsic chirality of the distorted cis diazene group dominates the ECD response, while for trans species the non-planarity of the polyphenyl arms induces peaks in the ECD spectrum. Finally, the possibility of obtaining a light-controlled chiral switch by proper functionalization is also speculated.

Benassi, Enrico; Corni, Stefano

2012-09-01

386

The Identification of Mono-, Di-, Tri-, and Tetragalactosyldiacylglycerols and their Natural Estolides in Oat Kernels†  

PubMed Central

Oat kernels were extracted with methanol, and glycolipid-enriched fractions were prepared using silica solid phase extraction. Using direct infusion electrospray ionization (ESI) tandem mass spectrometry (MS), high performance liquid chromatography (HPLC)-ESI-MS, and HPLC-atmospheric pressure chemical ionization (APCI)-MS, we confirmed previous reports that digalactosyldiacylglycerol (DGDG) was the most abundant glycolipid in oat kernels and confirmed a previous report of the presence of a DGDG mono-estolide in oat kernels. In the current study we also identified several additional natural galactolipid estolides: two new DGDG estolides (di- and tri-estolides), two trigalactosyldiacylglycerol (TriGDG) estolides (mono- and di-estolides), and one tetragalactosyldiacylglycerol (TetraGDG) estolide (monoestolide). The levels of total galactolipid estolides in oat kernels were estimated to be about 29% of the total glycolipid fraction. To our knowledge, this report is the first evidence of natural diand tri-estolides of polar lipids.

Moreau, Robert A.; Doehlert, Douglas C.; Welti, Ruth; Isaac, Giorgis; Roth, Mary; Tamura, Pamela; Nunez, Alberto

2014-01-01

387

Carbon Nanofiber Incorporated Silica Based Aerogels with Di-Isocyanate Cross-Linking  

NASA Technical Reports Server (NTRS)

Lightweight materials with excellent thermal insulating properties are highly sought after for a variety of aerospace and aeronautic applications. (1) Silica based aerogels with their high surface area and low relative densities are ideal for applications in extreme environments such as insulators for the Mars Rover battery. (2) However, the fragile nature of aerogel monoliths prevents their widespread use in more down to earth applications. We have shown that the fragile aerogel network can be cross-linked with a di-isocyanate via amine decorated surfaces to form a conformal coating. (3) This coating reinforces the neck regions between secondary silica particles and significantly strengthens the aerogels with only a small effect on density or porosity. Scheme 1 depicts the cross-linking reaction with the di-isocyanate and exhibits the stages that result in polymer cross-linked aerogel monoliths.

Vivod, Stephanie L.; Meador, Mary Ann B.; Capadona, Lynn A.; Sullivan, Roy M.; Ghosn, Louis J.; Clark, Nicholas; McCorkle, Linda

2008-01-01

388

Two DHH Subfamily 1 Proteins in Streptococcus pneumoniae Possess Cyclic Di-AMP Phosphodiesterase Activity and Affect Bacterial Growth and Virulence  

PubMed Central

Cyclic di-AMP (c-di-AMP) and cyclic di-GMP (c-di-GMP) are signaling molecules that play important roles in bacterial biology and pathogenesis. However, these nucleotides have not been explored in Streptococcus pneumoniae, an important bacterial pathogen. In this study, we characterized the c-di-AMP-associated genes of S. pneumoniae. The results showed that SPD_1392 (DacA) is a diadenylate cyclase that converts ATP to c-di-AMP. Both SPD_2032 (Pde1) and SPD_1153 (Pde2), which belong to the DHH subfamily 1 proteins, displayed c-di-AMP phosphodiesterase activity. Pde1 cleaved c-di-AMP into phosphoadenylyl adenosine (pApA), whereas Pde2 directly hydrolyzed c-di-AMP into AMP. Additionally, Pde2, but not Pde1, degraded pApA into AMP. Our results also demonstrated that both Pde1 and Pde2 played roles in bacterial growth, resistance to UV treatment, and virulence in a mouse pneumonia model. These results indicate that c-di-AMP homeostasis is essential for pneumococcal biology and disease.

Bai, Yinlan; Yang, Jun; Eisele, Leslie E.; Underwood, Adam J.; Koestler, Benjamin J.; Waters, Christopher M.; Metzger, Dennis W.

2013-01-01

389

Two DHH subfamily 1 proteins in Streptococcus pneumoniae possess cyclic di-AMP phosphodiesterase activity and affect bacterial growth and virulence.  

PubMed

Cyclic di-AMP (c-di-AMP) and cyclic di-GMP (c-di-GMP) are signaling molecules that play important roles in bacterial biology and pathogenesis. However, these nucleotides have not been explored in Streptococcus pneumoniae, an important bacterial pathogen. In this study, we characterized the c-di-AMP-associated genes of S. pneumoniae. The results showed that SPD_1392 (DacA) is a diadenylate cyclase that converts ATP to c-di-AMP. Both SPD_2032 (Pde1) and SPD_1153 (Pde2), which belong to the DHH subfamily 1 proteins, displayed c-di-AMP phosphodiesterase activity. Pde1 cleaved c-di-AMP into phosphoadenylyl adenosine (pApA), whereas Pde2 directly hydrolyzed c-di-AMP into AMP. Additionally, Pde2, but not Pde1, degraded pApA into AMP. Our results also demonstrated that both Pde1 and Pde2 played roles in bacterial growth, resistance to UV treatment, and virulence in a mouse pneumonia model. These results indicate that c-di-AMP homeostasis is essential for pneumococcal biology and disease. PMID:24013631

Bai, Yinlan; Yang, Jun; Eisele, Leslie E; Underwood, Adam J; Koestler, Benjamin J; Waters, Christopher M; Metzger, Dennis W; Bai, Guangchun

2013-11-01

390

Evaluation of microbial diversity during the manufacture of Fior di Latte di Agerola, a traditional raw milk pasta-filata cheese of the Naples area.  

PubMed

Microbial diversity of the raw milk for the production of Fior di Latte di Agerola and its changes during cheesemaking were studied. Viable counts showed that at the end of curd ripening, loads of lactic acid bacteria, both mesophilic and thermophilic rods and cocci, higher than those commonly evidenced in similar cheeses produced by using natural or commercial starters, were detected. Identification of 272 isolates, supported by molecular diagnostic aids, evidenced representative cultures of a high number of bacterial taxa of interest as participating in the process, although most of the isolates belonged to Lactococcus lactis and Lactobacillus helveticus species. RAPD-PCR and REA-PFGE biotyping were performed for the isolates of the above species and it was shown that most of the strains isolated from the raw milk occurred during the whole cheesemaking process, and an active role of these strains in the fermentation was supposed. The results offer further proof of the importance of the raw milk as source of technologically interesting strains of lactic acid bacteria capable of driving the fermentation of traditional cheeses. PMID:16569276

Coppola, Salvatore; Fusco, Vincenzina; Andolfi, Rosamaria; Aponte, Maria; Blaiotta, Giuseppe; Ercolini, Danilo; Moschetti, Giancarlo

2006-08-01

391

Composition and structure of complexes formed in the reaction of uranyl di(2-ethylhexyl)phosphate and tributyl phosphate or di-n-octyl sulfoxide in benzene solutions  

SciTech Connect

This paper reports on {sup 31}P NMR and IR studies of the interaction of tributyl phosphate (TBP) and di-n-octyl sulfoxide (DOSO) with polymer molecules of uranyl di-2-ethylhexyl phosphate (UO{sub 2}X{sub 2})p (I) in C{sub 6}H{sub 6} solutions. Detailed interpretations of the {sup 31}P NMR spectra and the v{sub as}(POO) IR bands and determination of the fraction of nonequivalent phosphorus atoms of X{sup -} anions and uranium (VI) atoms as well as the concentration of U(VI)-bonded TBP in I have shown that only a single TBP or DOSO molecule is coordinated to the uranium atoms of polymer I at C{sub TBP} = 0.1-2 M or C{sub DOSO}=0.1-0.5 M. In the case of 100% TBP, two TBP molecules are coordinated to some U(VI) atoms. Distribution of TBP (DOSO) molecules along the polymer chain agrees with the mean statistical value. The portion of terminal chelate POO-groups of X{sup -} anions is determined. The dependence of the degree of (UO{sub 2}X{sub 2})p{center_dot}nL (L = TBP, DOSO) polymerization on C{sub L} is obtained. Saturation of solutions with water only slightly affects the terminal POO-groups and has no effect on the distribution of L along the polymer chain of I.

Stoyanov, E.S.; Mikhailov, V.A.; Torgov, V.G. [and others

1995-05-01

392

Extraction of Np(IV) by Di-n-butylphosphoric and di-iso-amylphosphoric acids from aqueous HNO{sub 3}  

SciTech Connect

The interaction of Np(IV) with di-n-butylphosphoric (DBP) and di-iso-amylphosphoric (DIAP) acids is studied at room temperature in the biphasic extraction systems H{sub 2}O-HNO{sub 3}-TBP(TIAP)-n-decane (CCL{sub 4}) (TBP = tributylphosphate, TIAP = tri-iso-amylphosphate) for DBP (DIAP) concentrations from 0.91{center_dot}10{sup -3} to 4.16{center_dot}10{sup -2} M, HNO{sub 3} {le} 12 M, and TBP (TIAP) {le} 1.1 M. If n-decane is used as the solvent, Np concentrates mainly in the interfacial crud (IFC). As (HNO{sub 3}) in the aqueous phase and (TBP) (TIAP) in the organic phase increase, the amount of Np(IV) concentrated in the IFC decreases. In systems with CCl{sub 4}, Np(IV) does not concentrate in the IFC. Increasing (TBP) (TIAP) in the organic phase inhibits the interaction of Np(IV) with DBP (DIAP) in CCl{sub 4} and n-decane.

Solovkin, A.S.; Lobanov, A.V.

1994-07-01

393

Chamber studies on mass-transfer of di(2-ethylhexyl)phthalate (DEHP) and di- n-butylphthalate (DnBP) from emission sources into house dust  

NASA Astrophysics Data System (ADS)

For a number of phthalates and especially for di(2-ethylhexyl)phthalate (DEHP), surprisingly high house dust concentrations are reported in the literature. Therefore, the uptake of the most prominent compounds DEHP and di- n-butylphthalate (DnBP) from plasticized indoor materials into house dust samples of different organic content has been experimentally determined. The experiments have been performed within 45 days which is sufficient for the more volatile phthalate (DnBP) to reach equilibrium conditions. DnBP reaches considerably higher concentrations in the chamber air compared to real room measurements and, thus, also elevated dust concentrations. In contrast, the mass transfer of DEHP in the dust via the gas phase was significantly lower. However, small chamber experiments showed elevated mass transfer of DEHP in case of direct contact between emission source and sink. This aspect is experimentally determined using an plasticized PVC polymer with and without direct contact to house dust. A transfer into the dust could be observed in dependence of the initial concentration in the material. However, the results do not allow the differentiation between the two uptake mechanisms via capillary forces and contact to the material's boundary layer. The results illustrate that the reasons for elevated DEHP concentrations in dust indoors can be traced back to direct contact of source and sink, abrasion from the source, and transport via airborne particles.

Schripp, Tobias; Fauck, Christian; Salthammer, Tunga

2010-08-01

394

The bacterial second messenger c-di-GMP: Probing interactions with protein and RNA binding partners using cyclic dinucleotide analogs  

PubMed Central

The ability of bacteria to adapt to a changing environment is essential for their survival. One mechanism used to facilitate behavioral adaptations is the second messenger signaling molecule bis-(3?-5?)-cyclic dimeric guanosine monophosphate (c-di-GMP). c-di-GMP is widespread throughout the bacterial domain and plays a vital role in regulating the transition between the motile planktonic lifestyle and the sessile biofilm forming state. This second messenger also controls the virulence response of pathogenic organisms and is thought to be connected to quorum sensing, the process by which bacteria communicate with each other. The intracellular concentration of c-di-GMP is tightly regulated by the opposing enzymatic activities of diguanlyate cyclases and phosphodiesterases, which synthesize and degrade the second messenger, respectively. The change in the intracellular concentration of c-di-GMP is directly sensed by downstream targets of the second messenger, both protein and RNA, which induce the appropriate phenotypic response. This review will summarize our current state of knowledge of c-di-GMP signaling in bacteria with a focus on protein and RNA binding partners of the second messenger. Efforts towards the synthesis of c-di-GMP and its analogs are discussed as well as studies aimed at targeting these macromolecular effectors with chemically synthesized cyclic dinucleotide analogs.

Shanahan, Carly A.; Strobel, Scott A.

2013-01-01

395

Mutation in the C-Di-AMP Cyclase dacA Affects Fitness and Resistance of Methicillin Resistant Staphylococcus aureus  

PubMed Central

Faster growing and more virulent strains of methicillin resistant Staphylococcus aureus (MRSA) are increasingly displacing highly resistant MRSA. Elevated fitness in these MRSA is often accompanied by decreased and heterogeneous levels of methicillin resistance; however, the mechanisms for this phenomenon are not yet fully understood. Whole genome sequencing was used to investigate the genetic basis of this apparent correlation, in an isogenic MRSA strain pair that differed in methicillin resistance levels and fitness, with respect to growth rate. Sequencing revealed only one single nucleotide polymorphism (SNP) in the diadenylate cyclase gene dacA in the faster growing but less resistant strain. Diadenylate cyclases were recently discovered to synthesize the new second messenger cyclic diadenosine monophosphate (c-di-AMP). Introduction of this mutation into the highly resistant but slower growing strain reduced resistance and increased its growth rate, suggesting a direct connection between the dacA mutation and the phenotypic differences of these strains. Quantification of cellular c-di-AMP revealed that the dacA mutation decreased c-di-AMP levels resulting in reduced autolysis, increased salt tolerance and a reduction in the basal expression of the cell wall stress stimulon. These results indicate that c-di-AMP affects cell envelope-related signalling in S. aureus. The influence of c-di-AMP on growth rate and methicillin resistance in MRSA indicate that altering c-di-AMP levels could be a mechanism by which MRSA strains can increase their fitness levels by reducing their methicillin resistance levels.

Dengler, Vanina; McCallum, Nadine; Kiefer, Patrick; Christen, Philipp; Patrignani, Andrea; Vorholt, Julia A.; Berger-Bachi, Brigitte; Senn, Maria M.

2013-01-01

396

Synthesis and optical\\/chemical properties of triphenylamine derivatives based mono-, di-, and tri-indanedione  

Microsoft Academic Search

In this contribution, three triphenylamine derivatives were synthesized and their spectral properties were investigated. Knoevenagel\\u000a condensation of mono-, di-, and tri-aldehydes of triphenylamine with 1,3-indanedione yields D-?-A type dyes with push-pull\\u000a chromophores. The absorption and luminescence properties of the dyes were discussed in terms of their electronic structures.\\u000a The results of molecular orbital computer simulations, based on Material Studio, were

Xiaochuan Li; Young-Sung Kim; Sung-Hoon Kim; Kun Jun; Young-A Son

2009-01-01

397

Radical Polymerization of n-BMA Using a Di-Site Phase Transfer Catalyst  

Microsoft Academic Search

The di-site phase transfer catalyzed radical polymerization of butyl methacrylate with the phase transfer catalyst N,N?-diheptyl-N,N,N?,N?-tetramethyl-1,2-ethanediammonium dibromide (DHTMEDADB) was carried out in an aqueous-organic biphase system at 60 ± 1°C under nitrogeneous atmosphere at fixed pH and ionic strength. A suitable kinetic scheme has been proposed and its significance was discussed. The polymers obtained were investigated and characterized (FTIR, H-NMR and XRD

J. Usha; M. J. Umapathy

2009-01-01

398

Synthesis of thienylhydrogermanes and their transformations in the presence of di( tert -butyl) peroxide  

Microsoft Academic Search

A method was developed for the synthesis of thienylhydrogermanes RnGeH4?n (where R=2-thienyl, n=1–3), involving the reduction of the corresponding ethoxygermanes by lithium aluminum hydride under the conditions of phase-transfer catalysis. The transformations of thienylhydrogermanes under the influence of di(tert-butyl) peroxide were studied. Features of the mass-spectrometric behavior of thienylethoxygermanes were analyzed.

E. Lukevics; O. A. Pudova; I. Mazheika; S. Grinberga

1997-01-01

399

Coordination compounds based on 4,6-di- tert -butyl-2-nitrosophenol  

Microsoft Academic Search

New metal mono-, bis-, and tris(chelates) based on 4,6-di-tert-butyl-2-nitrosophenol were synthesized and their physicochemical properties were studied. Conclusions concerning the structures\\u000a of the complexes and the influence of the nature of the complexing metal on the electronic structure of the coordinated ligand\\u000a were drawn from X-ray diffraction, 1H NMR, magnetochemical, and electronic spectroscopy data.

S. N. Lyubchenko; A. M. Ionov; I. N. Shcherbakov; G. G. Aleksandrov; V. A. Kogan; A. Yu. Tsivadze

2006-01-01

400

Development and evaluation of systems for controlling parallel high di/dt thyratrons  

SciTech Connect

Increasing numbers of high power, high repetition rate applications dictate the use or thyratrons in multiple of hard parallel configurations to achieve the required rate of current rise, di/dt. This in turn demands the development of systems to control parallel thyratron commutation with nanosecond accuracy. Such systems must be capable of real-time, fully-automated control in multi-kilohertz applications while still remaining cost effective. This paper describes the evolution of such a control methodology and system.

Litton. A.; McDuff, G.

1982-01-01

401

Two-generation reproduction studies in Rats fed di-isodecyl phthalate  

Microsoft Academic Search

Di-isodecyl phthalate (DIDP) is a commercial plasticizer with low toxicity in many animal studies. The effects of dietary DIDP administration on fertility and developmental parameters were assessed in Sprague-Dawley rats utilizing two generation reproductive toxicity studies generally consistent with current regulatory guidelines. Dietary levels ranged from 0.02 to 0.8% (or approximately 15 to 600 mg\\/kg\\/day). In the reproductive studies, there

Leslie J. Hushka; Stacey J. Waterman; Laura H. Keller; Gary W. Trimmer; James J. Freeman; Jeffrey L. Ambroso; Mark Nicolich; Richard H. McKee

2001-01-01

402

Gas chromatographic analysis of synthetic glycidol esters, mono-, di- and triglycerides.  

PubMed

The gas chromatographic analysis of glycidol esters and mono-, di-,and triglycerides of palmitic-, stearic-, and oleic acid mixtures is described. The composition of the products was determined by gas chromatography on OV-17 after trimethylsilylation. Base-line separations between 1- and 2-monoglycerides and between 1,2- and 1,3-diglycerides were obtained. Isomerisation of the trimethylsilyl ethers of monoglycerides was not observed, contrary to published work. PMID:1269067

Engbersen, J A; van Stijn, F

1976-03-01

403

Potential of Ipomoea aquatica cultivars in phytoremediation of soils contaminated with di- n-butyl phthalate  

Microsoft Academic Search

Five different genotypic cultivars of Ipomoea aquatica commonly grown in Southeast Asia were cultivated to investigate their accumulation variation of di-n-butyl phthalate (DBP) and their potential for phytoremediation of three soils contaminated with DBP (4.5, 10.3 and 22.5mgkg?1). The results indicated different cultivar tolerance to DBP. DBP concentration in the shoots of the cultivars and residual DBP concentration in the

Quan-Ying Cai; Ce-Hui Mo; Qiao-Yun Zeng; Qi-Tang Wu; Jean-François Férard; Blanca Antizar-Ladislao

2008-01-01

404

USSAERO version D computer program development using ANSI standard FORTRAN 77 and DI-3000 graphics  

NASA Technical Reports Server (NTRS)

The D version of the Unified Subsonic Supersonic Aerodynamic Analysis (USSAERO) program is the result of numerous modifications and enhancements to the B01 version. These changes include conversion to ANSI standard FORTRAN 77; use of the DI-3000 graphics package; removal of the overlay structure; a revised input format; the addition of an input data analysis routine; and increasing the number of aeronautical components allowed.

Wiese, M. R.

1986-01-01

405

Rapid aging of neurotoxic esterase after inhibition by di-isopropyl phosphorofluoridate  

PubMed Central

1. It was proposed [Johnson (1974) J. Neurochem. 23, 785–789] that an essential step in the genesis of delayed neuropathy caused by some organophosphorus esters was aging of phosphorylated neurotoxic esterase, involving generation of a charged monosubstituted phosphoric acid residue on the protein. 2. Neurotoxic esterase of hen brain was inhibited with di-isopropyl phosphorofluoridate either unlabelled or mixed-labelled with 3H and 32P. 3. Reactivation of inhibited enzyme by KF was possible only immediately after a brief inhibition:aging at pH8.0 and 37°C occurred with a half-life of about 2–4min. 4. When the radiolabelled enzyme was studied no loss of label was observed during the expected aging period, but a change in the nature of the bound radioisotopes occurred (half-life=3.25min). 5. Alkaline hydrolysis of labelled enzyme liberated di-isopropyl phosphate at early times after labelling, but increasing amounts of monoisopropyl phosphate plus a volatile tritiated compound (possibly propan-2-ol) at later times. 6. Treatment of labelled enzyme with KF released di-isopropyl phosphate and caused reactivation of enzyme to similar degrees. It is concluded that the chemical change from di-isopropyl phosphoryl-enzyme to mono-isopropyl phosphoryl-enzyme and the loss of reactivatibility are related. 7. The rate of aging is similar at pH5.2, 6.5 and 8. Aging is unaffected by addition of reduced glutathione and imidazole at pH5.2 or 8, and none of the transferred 3H is trapped by these reagents. The mechanism of aging must be different from the better-known dealkylation aging of the cholinesterases.

Clothier, Bruce; Johnson, Martin K.

1979-01-01

406

Physical Realizations of Quantum Computing Are the DiVincenzo Criteria Fulfilled in 2004?  

NASA Astrophysics Data System (ADS)

Preface -- Obituary: Martti Mikael Salomaa -- DiVincenzo criteria and beyond / M. M. Salomaa and M. Nakahara -- Single-electron charge and spin qubit in semiconductor quantum dots / T. Fujisawa -- Superconducting quantum computing: status and prospects / F. K. Wilhelm and K. Semba -- Controlling three atomic qubits / H. Häffner ... [et al.] -- Liquid-state NMR quantum computer: Hamiltonian formalism and experiments / Y. Kondo, M. Nakahara and S. Tanimura -- Optical quantum computation / K. Nemoto and W. J. Munro.

Nakahara, Mikio; Kanemitsu, Shigeru; Salomaa, Martti M.; Takagi, Shin

2006-03-01

407

An artificial di-iron oxo-protein with phenol oxidase activity.  

PubMed

Here we report the de novo design and NMR structure of a four-helical bundle di-iron protein with phenol oxidase activity. The introduction of the cofactor-binding and phenol-binding sites required the incorporation of residues that were detrimental to the free energy of folding of the protein. Sufficient stability was, however, obtained by optimizing the sequence of a loop distant from the active site. PMID:19915535

Faiella, Marina; Andreozzi, Concetta; de Rosales, Rafael Torres Martin; Pavone, Vincenzo; Maglio, Ornella; Nastri, Flavia; DeGrado, William F; Lombardi, Angela

2009-12-01

408

Manufacture of Fior di Latte cheese by incorporation of probiotic lactobacilli.  

PubMed

This work aimed to select heat-resistant probiotic lactobacilli to be added to Fior di Latte (high-moisture cow milk Mozzarella) cheese. First, 18 probiotic strains belonging to Lactobacillus casei, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus reuteri were screened. Resistance to heating (65 or 55°C for 10 min) varied markedly between strains. Adaptation at 42°C for 10 min increased the heat resistance at 55°C for 10 min of all probiotic lactobacilli. Heat-adapted L. delbrueckii ssp. bulgaricus SP5 (decimal reduction time at 55°C of 227.4 min) and L. paracasei BGP1 (decimal reduction time at 55°C of 40.8 min) showed the highest survival under heat conditions that mimicked the stretching of the curd and were used for the manufacture of Fior di Latte cheese. Two technology options were chosen: chemical (addition of lactic acid to milk) or biological (Streptococcus thermophilus as starter culture) acidification with or without addition of probiotics. As determined by random amplified polymorphic DNA-PCR and 16S rRNA gene analyses, the cell density of L. delbrueckii ssp. bulgaricus SP5 and L. paracasei BGP1 in chemically or biologically acidified Fior di Latte cheese was approximately 8.0 log(10)cfu/g. Microbiological, compositional, biochemical, and sensory analyses (panel test by 30 untrained judges) showed that the use of L. delbrueckii ssp. bulgaricus SP5 and L. paracasei BGP1 enhanced flavor formation and shelf-life of Fior di Latte cheeses. PMID:22281315

Minervini, F; Siragusa, S; Faccia, M; Dal Bello, F; Gobbetti, M; De Angelis, M

2012-02-01

409

Effect of di- n-butyl phthalate (DBP) on activated sludge  

Microsoft Academic Search

The effects of di-n-butyl-phthalate (DBP) on both acclimated and unacclimated activated sludge were investigated in batch reactors. The IC50 values on the basis of maximum specific growth rate (?m), the chemical oxygen demand (COD) removal efficiency and the oxygen uptake rate (OUR) of unacclimated activated sludge was determined and found to be 78.8, 52.2 and 50.1mg\\/l, respectively. The COD removal

Wang Jianlong

2004-01-01

410

NEONATAL EXPOSURE TO DI(N-BUTYL) PHTHALATE (DBP) ALTERS MALE REPRODUCTIVE-TRACT DEVELOPMENT  

Microsoft Academic Search

The purpose of this study was to evaluate male reproductive-organ development in early postnatal male rats following neonatal exposure to di(n-butyl) phthalate (DBP) and identify a mechanism of action. Neonatal male rats were injected subcutaneously from d 5 to 14 after birth with corn oil (control) and DBP (5, 10, or 20 mg\\/animal). Animals were killed at postnatal day (PND)

Hyung Sik Kim; Tae Sung Kim; Jae-Ho Shin; Hyun Ju Moon; Il Hyun Kang; In Young Kim; Ji Young Oh; Soon Young Han

2004-01-01

411

Enzymatic activities in constructed wetlands and di- n-butyl phthalate (DBP) biodegradation  

Microsoft Academic Search

The bioaccumulation of phthalate acid esters (PAEs) from industrial products and their mutagenic action has been suggested to be a potential threat to human health. The effects of the most frequently identified PAE, Di-n-butyl phthalate (DBP), and its biodegradation, were examined by comparison of two small scale plots (SSP) of integrated vertical-flow constructed wetlands. The influent DBP concentration was 9.84mgl?1

Q. H. Zhou; Z. B. Wu; S. P. Cheng; F. He; G. P. Fu

2005-01-01

412

Microbial metabolism of di-butyl phthalate (DBP) by a denitrifying bacterium  

Microsoft Academic Search

The microbial degradation of di-n-butyl phthalate (DBP) by a denitrifying bacterium, with nitrate as the only electron acceptor, was investigated. The isolated denitrifying bacterium degraded up to 1.25 mM DBP within 100 h. A total of 10.0 mM nitrate severely inhibited cell growth by the toxic effect of the accumulated nitrite. The optimum nitrate concentration for cell growth and DBP

Wang Jianlong; Liu Ping; Qian Yi

1999-01-01

413

Testicular effects of di- n -butyl phthalate (DBP): Biochemical and histopathological alterations  

Microsoft Academic Search

Di-n-butyl phthalate (DBP) was administered to young male rats by gavage at the doses of 250, 500 and 1000 mg\\/kg body weight\\/day for 15 days. A significant decrease in testes weight was observed at 500 and 1000 mg\\/kg doses of DBP. Histopathological examination revealed marked degeneration of seminiferous tubules. The activities of testicular enzymes associated with postmeiotic spermatogenic cells, such

S. P. Srivastava; D. K. Saxena; S. V. Chandra; P. K. Seth

1990-01-01

414

Spectroscopic Ellipsometry Characterization of Variable Cu Concentration in Copper Indium Gallium di-Selenide Photovoltaic Films  

Microsoft Academic Search

Copper indium gallium di-selenide (CIGS) is among the most promising thin-film photovoltaic (PV) materials. Solar cells, using CIGS as an absorber layer, have achieved greater than 18 percent power conversion efficiencies on the laboratory scale. The best CIGS based photovoltaics have been created by utilizing the so-called three-stage process for the growth of the absorber layer. Standard substrates consist of

J. C. Verley; T. E. Furtak

2000-01-01

415

Diatom response to mid-Holocene climate change in Lago di Massaciuccoli (Tuscany, Italy)  

Microsoft Academic Search

A sedimentary sequence from the Mediterranean coastal basin of Lago di Massaciuccoli (Tuscany, Italy) was analyzed for diatoms,\\u000a covering two periods over the past ca. 7,000 years. The site was selected because it is situated in a sensitive position at\\u000a the limit between Mediterranean and Central European climates and biomes. Our focus is on the impact of accelerated human\\u000a activity during

Aldo Marchetto; Daniele Colombaroli; Willy Tinner

2008-01-01

416

Synthesis, mass spectrometry, and nuclear magnetic resonance characterization of Di-guerbet esters  

Microsoft Academic Search

Several Di-Guerbet esters (DGE) suitable for lubricant applications were synthesized from branched Guerbet alcohols and Guerbet\\u000a acids. The mass spectra of DGE under electron-ionization and positive chemical-ionization (PCI) conditions were recorded.\\u000a Gas chromatography-mass spectrometry, especially in PCI mode with methane as reagent gas, is an effective method for analyzing\\u000a DGE. In methane positive chemical-ionization mass spectrometry, the DGE give molecular

Gerhard Knothe; Kenneth D. Carlson

1998-01-01

417

A Bacterial Hemerythrin Domain Regulates Activity of a Vibrio cholerae Di-Guanylate Cyclase  

PubMed Central

The first demonstrated example of a regulatory function for a bacterial hemerythrin (Bhr) domain is reported. Bhrs have a characteristic sequence motif providing ligand residues for a type of non-heme diiron site that is known to bind O2 and undergo autoxidation. The amino acid sequence encoded by the gene, VC1216, from Vibrio cholerae O1 biovar El Tor str. N16961 contains an N-terminal Bhr domain connected to a C-terminal domain characteristic of bacterial di-guanylate cyclases (DGCs) that catalyze formation of cyclic di-(3?,5?)-guanosine monophosphate (c-di-GMP) from GTP. This protein, Vc Bhr-DGC, was found to contain two tightly bound non-heme iron atoms per protein monomer. The as-isolated protein showed the spectroscopic signatures of oxo/dicarboxylato-bridged non-heme diferric sites of previously characterized Bhr domains. The diiron site was capable of cycling between diferric and diferrous forms, the latter of which was stable only under anaerobic conditions, undergoing rapid autoxidation upon exposure to air. Vc Bhr-DGC showed approximately 10-times higher DGC activity in the diferrous relative to the diferric form. The level of intracellular c-di-GMP is known to regulate biofilm formation in Vibrio cholerae. The higher DGC activity of the diferrous Vc Bhr-DGC is consistent with induction of biofilm formation in low dioxygen environments. The non-heme diiron cofactor in the Bhr domain thus represents an alternative to heme or flavin for redox and/or diatomic gas sensing and regulation of DGC activity.

Schaller, Ruth A.; Ali, Syed Khalid; Klose, Karl E.; Kurtz, Donald M.

2012-01-01

418

TBX1 Is Responsible for Cardiovascular Defects in Velo-Cardio-Facial\\/DiGeorge Syndrome  

Microsoft Academic Search

Velo-cardio-facial syndrome (VCFS)\\/DiGeorge syndrome (DGS) is a human disorder characterized by a number of phenotypic features including cardiovascular defects. Most VCFS\\/DGS patients are hemizygous for a 1.5–3.0 Mb region of 22q11. To investigate the etiology of this disorder, we used a cre-loxP strategy to generate mice that are hemizygous for a 1.5 Mb deletion corresponding to that on 22q11. These

Sandra Merscher; Birgit Funke; Jonathan A. Epstein; Joerg Heyer; Anne Puech; Min Min Lu; Ramnik J. Xavier; Marie B. Demay; Robert G. Russell; Stephen Factor; Kazuhito Tokooya; Bruno St. Jore; Melissa Lopez; Raj K. Pandita; Marie Lia; Danaise Carrion; Hui Xu; Hubert Schorle; James B. Kobler; Peter Scambler; Anthony Wynshaw-Boris; Arthur I. Skoultchi; Bernice E. Morrow; Raju Kucherlapati

2001-01-01

419

Molecular Characterization of Tetralogy of Fallot Within DiGeorge Critical Region of the Chromosome 22  

Microsoft Academic Search

.   The purpose of this study was to determine whether the levels of heterozygosity and microdeletion of specific loci within\\u000a the DiGeorge critical region (del22q11) are associated with different phenotypes of tetralogy of Fallot (TF). Examinations\\u000a were conducted on 84 sporadic TF patients and their unaffected parents for del22q11, using the following 9 simple tandem repeat\\u000a polymorphic microsatellite markers: D22S420,

J.-H. Lu; M.-Y. Chung; H. Betau; H.-P. Chien; J.-K. Lu

2001-01-01

420

ProbDiVinE-MC: Multi-Core LTL Model Checker for Probabilistic Systems  

Microsoft Academic Search

We present a new version of ProbDiVinE - a parallel tool for verification of probabilistic systems against proper- ties formulated in linear temporal logic. Unlike the pre- vious release (1), the new version of the tool allows for both quantitative and qualitative model-checking. It is also strictly multi-threaded, therefore, protects users f rom unwanted burden of parallel computing in a

Lubos Brim; Jana Tumov

421

Strength and nature of hydrogen bonding interactions in mono- and di-hydrated formamide complexes.  

PubMed

In this work, mono- and di-hydrated complexes of the formamide were studied. The calculations were performed at the MP2/6-311++G(d,p) level of approximation. The atoms in molecules theory (AIM), based on the topological properties of the electronic density distribution, was used to characterize the different types of bonds. The analysis of the hydrogen bonds (H-bonds) in the most stable mono- and di-hydrated formamide complexes shows a mutual reinforcement of the interactions, and some of these complexes can be considered as "bifunctional hydrogen bonding hydration complexes". In addition, we analyzed how the strength and the nature of the interactions, in mono-hydrated complexes, are modified by the presence of a second water molecule in di-hydrated formamide complexes. Structural changes, cooperativity, and electron density redistributions demonstrate that the H-bonds are stronger in the di-hydrated complexes than in the corresponding mono-hydrated complexes, wherein the ?- and ?-electron delocalization were found. To explain the nature of such interactions, we carried out the atoms in molecules theory in conjunction with reduced variational space self-consistent field (RVS) decomposition analysis. On the basis of the local Virial theorem, the characteristics of the local electron energy density components at the bond critical points (BCPs) (the 1/4? (2)?(b) component of electron energy density and the kinetic energy density) were analyzed. These parameters were used in conjunction with the electron density and the Laplacian of the electron density to analyze the characteristics of the interactions. The analysis of the interaction energy components for the systems considered indicates that the strengthening of the hydrogen bonds is manifested by an increased contribution of the electrostatic energy component represented by the kinetic energy density at the BCP. PMID:21506592

Angelina, Emilio L; Peruchena, Nélida M

2011-05-12

422

Investigating Self-Assembly and Metal Nanoclusters in Aqueous Di-Block Copolymer Solutions  

SciTech Connect

Self-assembling properties of di-block copolymers/ surfactant hybrids in aqueous solution can be exploited to obtain metal nanoparticles stable dispersion. Results will be presented here for polystyrene-block-poly(ethylene oxide) solutions. A SANS structural investigation has been performed over different molecular weights of both hydrophilic and hydrophobic block, by varying temperature and concentration of the copolymer. A SAXS characterization of micellar systems containing Pt nanoparticles is reported.

Lo Celso, F.

2002-12-01

423

Predictive zero-dimensional combustion model for DI diesel engine feed-forward control  

Microsoft Academic Search

An innovative zero-dimensional predictive combustion model has been developed for the estimation of HRR (heat release rate) and in-cylinder pressure traces. This model has been assessed and applied to conventional and PCCI (premixed charge compression ignition) DI diesel engines for model-based feed-forward control purposes.The injection rate profile is calculated on the basis of the injected fuel quantities and on the

Andrea Emilio Catania; Roberto Finesso; Ezio Spessa

2011-01-01

424

MoBiDiCK: A Tool for Distributed Computing on the Internet  

Microsoft Academic Search

We have developed a system for distributed computing called MoBiDiCK. This system can be used to marshal a large number of processors across the Internet in order to have the m collaborate on a single computation. CGI programs on the volunteer processors perfo rm the computations. These utilize a message-passing API and control\\/synchronization f ormalism we have developed that uses

Moyez Dharsee; Christopher W. V. Hogue

2000-01-01

425

Separation and determination of mono-, Di, and triglycerides in monoglyceride concentrates  

Microsoft Academic Search

Summary  Monoglyceride concentrates are quantitatively separated into mono-, di-, and triglyceride components on silica gel columns\\u000a by an adsorption chromatographic technique. The separated glycerides are determined gravimetrically. The adsorption on silica\\u000a gel is dependent on the number of hydroxyl groups in the molecule, and the influence of unsaturation and chain length is minimized.\\u000a Combinations of benzene and ethyl ether are used

Patricia Quinlin; Herman J. Weiser

1958-01-01

426

An artificial di-iron oxo-protein with phenol oxidase activity  

PubMed Central

Here we report the de novo design and NMR structure of a four-helical bundle di-iron protein with phenol oxidase activity. The introduction of the cofactor-binding and phenol-binding sites required the incorporation of residues that were detrimental to the free energy of folding of the protein. Sufficient stability was, however, obtained by optimizing the sequence of a loop distant from the active site.

Faiella, Marina; Andreozzi, Concetta; de Rosales, Rafael Torres Martin; Pavone, Vincenzo; Maglio, Ornella; Nastri, Flavia; DeGrado, William F; Lombardi, Angela

2013-01-01

427

Characterization and biological effects of di-hydroxylated compounds deriving from the lipoxygenation of ALA.  

PubMed

We have recently described a di-hydroxylated compound called protectin DX (PDX) which derives from docosahexaenoic acid (DHA) by double lipoxygenation. PDX exhibits anti-aggregatory and anti-inflammatory properties, that are also exhibited by similar molecules, called poxytrins, which possess the same E,Z,E conjugated triene geometry, and are synthesized from other polyunsaturated fatty acids with 22 or 20 carbons. Here we present new biological activities of di-hydroxylated metabolites deriving from ?-linolenic acid (18:3n-3) treated by soybean 15-lipoxygenase (sLOX). We show that 18:3n-3 is converted by sLOX into mainly 13(S)-OH-18:3 after reduction of the hydroperoxide product. But surprisingly, and in contrast to DHA which is metabolized into only one di-hydroxylated compound, 18:3n-3 leads to four di-hydroxylated fatty acid isomers. We report here the complete characterization of these compounds using high field NMR and GC-MS techniques, and some of their biological activities. These compounds are: 9(R),16(S)-dihydroxy-10E,12E,14E-octadecatrienoic acid, 9(S),16(S)-dihydroxy-10E,12E,14E-octadecatrienoic acid, 9(S),16(S)-dihydroxy-10E,12Z,14E-octadecatrienoic acid, and 9(R),16(S)-dihydroxy-10E,12Z,14E-octadecatrienoic acid. They can also be synthesized by the human recombinant 15-lipoxygenase (type 2). Their inhibitory effect on blood platelet and anti-inflammatory properties were compared with those already reported for PDX. PMID:23740966

Liu, Miao; Chen, Ping; Véricel, Evelyne; Lelli, Moreno; Béguin, Laetitia; Lagarde, Michel; Guichardant, Michel

2013-08-01

428

Investigation on Particulate Oxidation from a DI Diesel Engine Fueled with Three Fuels  

Microsoft Academic Search

In this study, particles generated from a direct-injection (DI) diesel engine fueled with biodiesel, ultra low sulfur diesel (ULSD, <10ppm-wt), and low sulfur diesel (LSD, <500ppm-wt) were investigated experimentally for their oxidation properties, using the thermogravimetry analysis (TGA), at five engine loads. Kinetics analysis of particulate oxidation was conducted based on the mass loss curves obtained from the TGA. The

Tian Lu; C. S. Cheung; Zhen Huang

2012-01-01

429

Aerobic biodegradation of di- n -butyl phthalate by Xiangjiang River sediment and microflora analysis  

Microsoft Academic Search

Di-n-butyl phthalate (DBP), one of phthalate acid esters (PAEs), was investigated to determine its biodegradation rate using Xiangjiang\\u000a River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated\\u000a with an initial concentration of DBP of 100 mg\\/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the

Hong-bo Zhou; Feng Lin; Pei-lei Hu; De-cai Jing; Hong-qiang Ren; Jing Zhao; Guan-zhou Qiu

2009-01-01

430

Evaluation of Di-Sansalvamide A derivatives: Synthesis, structure-activity relationship, and mechanism of action  

PubMed Central

Described is the SAR of 18 Di-Sansalvamide A derivatives and the mechanism of action of the most potent compound. We show that this scaffold is a promising lead in the development of novel cancer therapeutics because it is: cytotoxic at nanomolar potency, inhibits a well-established oncogenic target (Hsp90), and does not share structural motifs with current drugs on the market.

Alexander, Leslie D.; Sellers, Robert P.; Davis, Melinda R.; Ardi, Veronica C.; Johnson, Victoria A.; Vasko, Robert C.; McAlpine, Shelli R.

2009-01-01

431

Thermal field-flow fractionation of colloidal materials: Methylmethacrylate-styrene linear di-block copolymers  

Microsoft Academic Search

Summary  Model methylmethacrylate-styrene, linear di-block, copolymers were used to investigate the respective influnnces of temperature,\\u000a of molar mass and of chemical composition on their Soret coefficient, sT, by means of thermal field-flow fractionation (thermal FFF) in toluene and in THF. A recently developed thermal FFF retention\\u000a model, which takes into account the variation of the basic FFF parameter ? with temperature,

C. Van Batten; M. Hoyos; M. Martin

1997-01-01

432

Di(2-ethylhexyl)-phthalate affects lipid profiling in fetal rat brain upon maternal exposure  

Microsoft Academic Search

Lipids, especially essential fatty acids (EFAs), play critical roles in guiding proper fetal development. Exposure to xenobiotics\\u000a that may alter the fetal supply of EFAs\\/lipids could potentially lead to fetotoxicity. In this study, we investigated the\\u000a effects of the peroxisome proliferator chemical, di-(2-ethylhexyl)-phthalate (DEHP), on the lipid metabolomic profile of the\\u000a rat fetal brain upon maternal exposure during gestation. Female

Yan Xu; Shruti Agrawal; Thomas J. Cook; Gregory T. Knipp

2007-01-01

433

Photoluminescent, transparent and flexible di-ureasil hybrids containing CdSe\\/ZnS quantum dots  

Microsoft Academic Search

We describe, in this paper, the sol–gel synthesis of di-ureasil based nanocomposites prepared in situ in the presence of organically capped CdSe quantum dots (QDs) or CdSe QDs which have been coated with a ZnS shell. For the latter a new chemical route to coat the CdSe QDs with ZnS shells was investigated and is now reported. The QDs became

Márcia C Neves; Manuel A Martins; Paula C R Soares-Santos; Protima Rauwel; Rute A S Ferreira; Teresa Monteiro; Luís D Carlos; Tito Trindade

2008-01-01

434

Testicular toxicity of di-(2-ethylhexyl)phthalate in young Sprague–Dawley rats  

Microsoft Academic Search

Di-(2-ethylhexyl)phthalate (DEHP), used widely in the manufacture of plastics, is a well-known reproductive toxicant. It causes apoptosis and loss of spermatogenic cells, resulting in testicular atrophy. Reports are scarce in the literature on the progression of apoptosis following repeated doses of phthalates. DEHP's mechanism of inducing testicular atrophy has been associated with depletion of zinc in the testis. ZnT-1 is

Jung D Park; Sultan S. M Habeebu; Curtis D Klaassen

2002-01-01

435

Kinetics of di-(2-ethylhexyl)phthalate mineralization in sludge-amended soil  

Microsoft Academic Search

Sewage sludge is frequently used as a soil fertilizer although it may contain elevated concentrations of priority pollutants including di-(2-ethylhexyl)phthalate (DEHP). In the present study, the kinetics of microbial [[sup 14]C]DEHP mineralization was studied in laboratory microcosms with sewage sludge and agricultural soil. A biphasic model with two independent kinetic expressions was used to fit the mineralization data. The initial

Peter Lindequist Madsen; Jesper Bandsholm Thyme; Kaj Henriksen; P. Moeldrup; Peter Roslev

1999-01-01

436

Recovery of Chromium from Electroplating Wastewater Using DI 2?(Ethylhexyl) Phosphoric Acid  

Microsoft Academic Search

Extraction of chromium (III) using D2EHPA (di 2?ethylhexyl phosphoric acid) in kerosene was carried out. A study was carried out to optimize the conditions, namely pH, carrier D2EHPA, aqueous and organic ratio, and reaction time. The effect of chloride and sulphate concentration on the extraction process was studied. The tri?butyl phosphate (TBP) was used as a phase modifier to facilitate

J. Senthilnathan; S. Mohan; K. Palanivelu

2005-01-01

437

Mono(3-Carboxypropyl) Phthalate, A Metabolite of Di-n-Octyl Phthalate  

Microsoft Academic Search

Di-n-octyl phthalate (DnOP) is found as a component of mixed C6–C10 linear-chain phthalates used as plasticizers in various polyvinyl chloride applications, including flooring and carpet tiles. Following exposure and absorption, DnOP is metabolized to its hydrolytic monoester, mono-n-octyl phthalate (MnOP), and other oxidative products. The urinary levels of one of these oxidative metabolites, mono-(3-carboxypropyl) phthalate (MCPP), were about 560-fold higher

Antonia M. Calafat; Manori J. Silva; John A. Reidy; L. Earl Gray; Ella Samandar; James L. Preau Jr; Arnetra R. Herbert; Larry L. Needham

2006-01-01

438

Integrated biosorption and photocatalytic oxidation treatment of di(2-ethylhexyl)phthalate  

Microsoft Academic Search

Di(2-ethylhexyl)phthalate (DEHP), a toxic phthalate ester, is a ubiquitous contaminant due to its extensive use and persistence.\\u000a No available treatment method can cost-effectively remove it from industrial wastewater. In a previous study, DEHP was effectively\\u000a removed from aqueous solution by adsorption onto the biomass of selected seaweed, i.e., beached seaweed and Sargassum siliquastrum. Since biosorption cannot detoxify DEHP, the degradation

H. W. Chan; C. M. Chan; P. O. Ang; P. K. Wong

2007-01-01

439

HMQV: A High-Performance Secure Di-e-Hellman Protocol (Extended Abstract) ?  

Microsoft Academic Search

The MQV protocol of Law, Menezes, Qu, Solinas and Van- stone is possibly the most e-cient of all known authenticated Di-e- Hellman protocols based on public-key authentication. In addition to great performance, the protocol has been designed to achieve a remark- able list of security properties. As a result MQV has been widely stan- dardized, and has recently been chosen

Hugo Krawczyk

440

Tris(diisopropyl di-thio-phosphato-?2 S,S?)ruthenium(III)  

PubMed Central

In the title complex, [Ru(C6H14O2PS2)3], the coordination environment of the RuIII atom is distorted octa­hedral, defined by six S atoms from three S,S?-bidentate diisopropyl di­thio­phosphate ligands. The average Ru—S bond length is 2.41?(1)?Å and the average S—Ru—S bite angle is 81.13?(19)°.

Chao, Guo-Ping; Wu, Xiuli; Shi, Hua-Tian; Chen, Qun; Zhang, Qian-Feng

2013-01-01

441

Scanning Tunneling Microscopy investigation of multilayer diF-TES-ADT on Au(111)  

NASA Astrophysics Data System (ADS)

Organic thin film transistors (OTFT) partially composed of solution processed 2,8-difluoro-5,11-bis(triethylsilylethynyl)-anthradithiophene (diF-TES-ADT) have shown high performance with hole mobilities up to 1 cm^2/(V s). Pretreatment of the gold electrodes results in growth of large diF-TES-ADT crystals extending well out into the channel of the OTFT. Without electrode pretreatment, the crystal sizes are small and possess a non-preferred molecular orientation. We have chosen to investigate the reasons for the reduced crystal size of these films on untreated gold electrodes by studying a model system generated by vapor deposition of multilayers of diF-TES-ADT on Au(111). The initial wetting layer forms a highly ordered film such that the anthradithiophene backbone is oriented parallel to the substrate and the unit cell is 1.49 nm x 1.25 nm with an included angle of 56.8^o. The second layer is poorly ordered with only weak evidence of crystallinity in small regions. Growth beyond the second layer appears essentially bulk-like and crystalline with domain sizes that are potentially limited by the disordered bilayer growth.

Huston, Shawn; Wang, Jiuyang; Loth, Marsha; Anthony, John; Conrad, Brad; Dougherty, Daniel

2013-03-01

442

DiGeorge Syndrome Presenting as Hypocalcaemia-Induced Seizures in Adulthood  

PubMed Central

Introduction. DiGeorge syndrome is a developmental defect commonly caused by a microdeletion on the long arm of chromosome 22 or less frequently by a deletion of the short arm of chromosome 10. Case report. We report a case of a gentleman with mild dysmorphic features who presented with hypocalcaemia-induced seizures and an associated thyroid mass with a background of learning difficulties and abnormal immune function. Discussion. DiGeorge syndrome was initially described in 1967 by Angelo DiGeorge. The majority of cases are due to a novel mutation. The resulting learning difficulties, congenital heart disease, palatal abnormalities, hypoplasia/aplasia of the parathyroid and thymus glands, and immune deficiency generally lead to diagnosis in childhood. Presentation in adulthood is rare but must be borne in mind when dealing with cases of hypocalcaemia even in the absence of florid phenotypic features. A link with malignant disease has also been reported and should lead to prompt investigation of concerning masses.

Grech Marguerat, Deborah; Psaila, Josephine; Attard, Alexander

2013-01-01

443

Di- or polysulphide-bound biomarkers in sulphur-rich geomacromolecules as revealed by selective chemolysis  

NASA Astrophysics Data System (ADS)

Three types of sulphur-rich high-molecular-weight material in the alkylsulphide, the polar, and the asphaltene fractions isolated from the bitumen of an immature bituminous shale from the Vena del Gesso basin (Italy) were desulphurised using Raney Ni and were treated with MeLi/MeI, a chemical degradation method which cleaves selectively and quantitatively di- or polysulphide linkages. The products formed were characterised by gas chromatography-mass spectrometry. Raney Ni desulphurisation revealed that these S-rich macromolecules are in substantial part composed of sulphur-linked biomarkers with linear, branched, isoprenoid, steroid, hopanoid, and carotenoid carbon skeletons. MeLi/Mel treatment provided evidence that a major part of the total amount of macromolecularly bound biomarkers are linked via di- or polysulphide moieties to the macromolecular network. Since the di- or polysulphide linkages are attached at specific positions of the bound biomarkers it is proposed that they are formed by intermolecular incorporation reactions of HS x- into low-molecular-weight functionalised biological lipids during early diagenesis. The different properties (solubility and molecular weight) of the sulphur-rich macromolecules in the alkylsulphide, the resin, and the asphaltene fractions can be explained simply by differences in degree of sulphur cross-linking.

Kohnen, Math E. l.; Sinninghe Damsté, Jaap S.; Kock-van Dalen, A. c.; Jan, W. De Leeuw

1991-05-01

444

Fluorescent labeling of dendritic spines in cell cultures with the carbocyanine dye "DiI"  

PubMed Central

Analyzing cell morphology is a key component to understand neuronal function. Several staining techniques have been developed to facilitate the morphological analysis of neurons, including the use of fluorescent markers, such as DiI (1,1?-dioctadecyl-3,3,3?,3?-tetramethylindocarbocyanine perchlorate). DiI is a carbocyanine membrane dye that exhibits enhanced fluorescence upon insertion of its lipophilic hydrocarbon chains into the lipid membrane of cells. The high photostability and prominent fluorescence of the dye serves as an effective means of illuminating cellular architecture in individual neurons, including detailed dendritic arborizations and spines in cell culture and tissue sections. Here, we specifically optimized a simple and reliable method to fluorescently label and visualize dissociated hippocampal neurons using DiI and high-resolution confocal microscopic imaging. With high efficacy, this method accurately labels neuronal and synaptic morphology to permit quantitative analysis of dendritic spines. Accurate imaging techniques of these fine neuronal specializations are vital to the study of their morphology and can help delineate structure-function relationships in the central nervous system.

Cheng, Connie; Trzcinski, Olivia; Doering, Laurie C.

2014-01-01

445

Novel Mono-, Di-, and Trimethylornithine Membrane Lipids in Northern Wetland Planctomycetes  

PubMed Central

Northern peatlands represent a significant global carbon store and commonly originate from Sphagnum moss-dominated wetlands. These ombrotrophic ecosystems are rain fed, resulting in nutrient-poor, acidic conditions. Members of the bacterial phylum Planctomycetes are highly abundant and appear to play an important role in the decomposition of Sphagnum-derived litter in these ecosystems. High-performance liquid chromatography coupled to high-resolution accurate-mass mass spectrometry (HPLC-HRAM/MS) analysis of lipid extracts of four isolated planctomycetes from wetlands of European north Russia revealed novel ornithine membrane lipids (OLs) that are mono-, di-, and trimethylated at the ?-nitrogen position of the ornithine head group. Nuclear magnetic resonance (NMR) analysis of the isolated trimethylornithine lipid confirmed the structural identification. Similar fatty acid distributions between mono-, di-, and trimethylornithine lipids suggest that the three lipid classes are biosynthetically linked, as in the sequential methylation of the terminal nitrogen in phosphatidylethanolamine to produce phosphatidylcholine. The mono-, di-, and trimethylornithine lipids described here represent the first report of methylation of the ornithine head groups in biological membranes. Various bacteria are known to produce OLs under phosphorus limitation or fatty-acid-hydroxylated OLs under thermal or acid stress. The sequential methylation of OLs, leading to a charged choline-like moiety in the trimethylornithine lipid head group, may be an adaptation to provide membrane stability under acidic conditions without the use of scarce phosphate in nutrient-poor ombrotrophic wetlands.

Hopmans, Ellen C.; Rijpstra, W. Irene C.; Villanueva, Laura; Dedysh, Svetlana N.; Kulichevskaya, Irina S.; Wienk, Hans; Schoutsen, Frans; Sinninghe Damste, Jaap S.

2013-01-01

446

Di- or polysulphide-bound biomarkers in sulphur-rich geomacromolecules as revealed by selective chemolysis  

SciTech Connect

Three types of sulphur-rich high-molecular-weight material in the alkylsulphide, the polar, and the asphaltene fractions isolated from the bitumen of an immature bituminous shale from the Vena del Gesso basin (Italy) were desulphurised using Raney Ni and were treated with MeLi/MeI, a chemical degradation method which cleaves selectively and quantitatively di- or polysulphide linkages. The products formed were characterized by gas chromatography-mass spectrometry. Raney Ni desulphurisation revealed that these S-rich macromolecules are in substantial part composed of sulphur-linked biomarkers with linear, branched, isoprenoid, steroid, hopanoid, and carotenoid carbon skeletons. MeLi/MeI treatment provided evidence that a major part of the total amount of macromolecularly bound biomarkers are linked via di- or polysulphide moieties to the macromolecular network. Since the di- or polysulphide linkages are attached at specific positions of the bound biomarkers it is proposed that they are formed by intermolecular incorporation reactions of HS{sub x}{sup {minus}} into low-molecular-weight functionalized biological lipids during early diagenesis. The different properties (solubility and molecular weight) of the sulphur-rich macromolecules in the alkylsulphide, the resin, and the asphaltene fractions can be explained simply by differences in degree of sulphur cross-linking.

Kohnen, M.E.L.; Sinninghe Damste, J.S.; Kock-Van Dalen, A.C.; De Leeuw, J.W. (Delft Univ. of Technology (Netherlands))

1991-05-01

447

Photoluminescent, transparent and flexible di-ureasil hybrids containing CdSe/ZnS quantum dots.  

PubMed

We describe, in this paper, the sol-gel synthesis of di-ureasil based nanocomposites prepared in situ in the presence of organically capped CdSe quantum dots (QDs) or CdSe QDs which have been coated with a ZnS shell. For the latter a new chemical route to coat the CdSe QDs with ZnS shells was investigated and is now reported. The QDs became well dispersed in the final nanocomposites, whose microstructural homogeneity was evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses. In order to understand the optical behaviour of di-ureasil containing QDs, a detailed photoluminescent study was undertaken for a selected particle size distribution of ZnS coated CdSe QDs (d?4.5 nm). Emission quantum yields up to 0.11 were measured in the final nanocomposites that present a huge (between 3 and 6 orders of magnitude) increase in the lifetime of the QDs (relative to that of isolated ones), as a result of energy transfer occurring between the intimately mixed di-ureasil host and the QDs. PMID:21825615

Neves, Márcia C; Martins, Manuel A; Soares-Santos, Paula C R; Rauwel, Protima; Ferreira, Rute A S; Monteiro, Teresa; Carlos, Luís D; Trindade, Tito

2008-04-16

448

Neuronally expressed Ras-family GTPase Di-Ras modulates synaptic activity in Caenorhabditis elegans.  

PubMed

Ras-family GTPases regulate a wide variety of cellular functions including cell growth and differentiation. Di-Ras, which belongs to a distinct subfamily of Ras-family GTPases, is expressed predominantly in brain, but the role of Di-Ras in nervous systems remains totally unknown. Here, we report that the Caenorhabditis elegans Di-Ras homologue drn-1 is expressed specifically in neuronal cells and involved in synaptic function at neuromuscular junctions. Loss of function of drn-1 conferred resistance to the acetylcholinesterase inhibitor aldicarb and partially suppressed the aldicarb-hypersensitive phenotypes of heterotrimeric G-protein mutants, in which acetylcholine release is up-regulated. drn-1 mutants displayed no apparent defects in the axonal distribution of the membrane-bound second messenger diacylglycerol (DAG), which is a key stimulator of acetylcholine release. Finally, we have identified EPAC-1, a C. elegans Epac homologue, as a binding partner for DRN-1. Deletion mutants of epac-1 displayed an aldicarb-resistant phenotype as drn-1 mutants. Genetic analysis of drn-1 and epac-1 showed that they acted in the same pathway to control acetylcholine release. Furthermore, DRN-1 and EPAC-1 were co-immunoprecipitated. These findings suggest that DRN-1 may function cooperatively with EPAC-1 to modulate synaptic activity in C. elegans. PMID:22897658

Tada, Minoru; Gengyo-Ando, Keiko; Kobayashi, Tetsuo; Fukuyama, Masamitsu; Mitani, Shohei; Kontani, Kenji; Katada, Toshiaki

2012-09-01

449

Biodegradation of di-n-butyl phthalate by a newly isolated halotolerant Sphingobium sp.  

PubMed

A Gram-negative strain (TJ) capable of growing aerobically on mixed phthalate esters (PAEs) as the sole carbon and energy source was isolated from the Haihe estuary, Tianjin, China. It was identified as belonging to the Sphingobium genus on the basis of morphological and physiological characteristics and 16S rRNA and gyrb gene sequencing. The batch tests for biodegradation of di-n-butyl phthalate (DBP) by the Sphingobium sp. TJ showed that the optimum conditions were 30 °C, pH 7.0, and the absence of NaCl. Stain TJ could tolerate up to 4% NaCl in minimal salt medium supplemented with DBP, although the DBP degradation rates slowed as NaCl concentration increased. In addition, substrate tests showed that strain TJ could utilize shorter side-chained PAEs, such as dimethyl phthalate and diethyl phthalate, but could not metabolize long-chained PAEs, such as di-n-octyl phthalate, diisooctyl phthalate, and di-(2-ethyl-hexyl) phthalate. To our knowledge, this is the first report on the biodegradation characteristics of DBP by a member of the Sphingobium genus. PMID:24336064

Jin, Decai; Kong, Xiao; Cui, Bingjian; Bai, Zhihui; Zhang, Hongxun

2013-01-01

450

Cytogenetic findings in a prospective series of patients with DiGeorge anomaly.  

PubMed

High-resolution cytogenetics analysis of peripheral blood lymphocytes was done prospectively on 27 of 28 patients with features of DiGeorge anomaly. Twenty-two patients (81%) had normal chromosome studies with no detectable deletion in chromosome 22. Five patients (18%) had demonstrable chromosome abnormalities. Three patients had monosomy 22q11, one due to a 4q;22q translocation, one due to a 20q;22q translocation, and one due to an interstitial deletion of 22q11. One patient had monosomy 10p13, and one patient had monosomy 18q21.33, although the latter had subsequent resolution of T-cell defects. These findings are consistent with the heterogeneity of DiGeorge anomaly but confirm the association with monosomy 22q11 in some cases. However, monosomy 10p13 may also lead to this phenotype. Because of these associated chromosome findings, cytogenetic analyses should be done on patients with suspected DiGeorge anomaly. This is particularly important since many of the abnormalities involving chromosome 22 are translocations that can be familial with a higher recurrence risk. Since only one subtle, interstitial deletion of chromosome 22 was observed, it is not clear whether high-resolution cytogenetic analysis is cost beneficial for all such patients. PMID:3189331

Greenberg, F; Elder, F F; Haffner, P; Northrup, H; Ledbetter, D H

1988-11-01

451

LtmA, a novel cyclic di-GMP-responsive activator, broadly regulates the expression of lipid transport and metabolism genes in Mycobacterium smegmatis  

PubMed Central

In a bis-(3?-5?)-cyclic dimeric guanosine monophosphate (c-di-GMP)/transcription factor binding screen, we identified Mycobacterium smegmatis Ms6479 as the first c-di-GMP-responsive transcriptional factor in mycobacteria. Ms6479 could specifically bind with c-di-GMP and recognize the promoters of 37 lipid transport and metabolism genes. c-di-GMP could enhance the ability of Ms6479 to bind to its target DNA. Furthermore, our results establish Ms6479 as a global activator that positively regulates the expression of diverse target genes. Overexpression of Ms6479 in M. smegmatis significantly reduced the permeability of the cell wall to crystal violet and increased mycobacterial resistance to anti-tuberculosis antibiotics. Interestingly, Ms6479 lacks the previously reported c-di-GMP binding motifs. Our findings introduce Ms6479 (here designated LtmA for lipid transport and metabolism activator) as a new c-di-GMP-responsive regulator.

Li, Weihui; He, Zheng-Guo

2012-01-01

452

Crystal structure of an HD-GYP domain cyclic-di-GMP phosphodiesterase reveals an enzyme with a novel trinuclear catalytic iron centre.  

PubMed

Bis-(3',5') cyclic di-guanylate (c-di-GMP) is a key bacterial second messenger that is implicated in the regulation of many crucial processes that include biofilm formation, motility and virulence. Cellular levels of c-di-GMP are controlled through synthesis by GGDEF domain diguanylate cyclases and degradation by two classes of phosphodiesterase with EAL or HD-GYP domains. Here, we have determined the structure of an enzymatically active HD-GYP domain protein from Persephonella marina (PmGH) alone, in complex with substrate (c-di-GMP) and final reaction product (GMP). The structures reveal a novel trinuclear iron binding site, which is implicated in catalysis and identify residues involved in recognition of c-di-GMP. This structure completes the picture of all domains involved in c-di-GMP metabolism and reveals that the HD-GYP family splits into two distinct subgroups containing bi- and trinuclear metal centres. PMID:24176013

Bellini, Dom; Caly, Delphine L; McCarthy, Yvonne; Bumann, Mario; An, Shi-Qi; Dow, J Maxwell; Ryan, Robert P; Walsh, Martin A

2014-01-01

453

Single-factor scoring validation for the Health Assessment Questionnaire-Disability Index (HAQ-DI) in patients with systemic sclerosis and comparison with early rheumatoid arthritis patients  

Microsoft Academic Search

Objective  Structural validity for the Health Assessment Questionnaire-Disability Index (HAQ-DI) has recently been provided for patients with rheumatoid arthritis (RA). The goal of the current study was to examine the structural validity of the HAQ-DI in patients with systemic sclerosis (SSc, scleroderma) and to compare its performance with that in patients with RA.Methods  The HAQ-DI structural validity was first assessed in a

Jason C. Cole; Dinesh Khanna; Philip J. Clements; James R. Seibold; Donald P. Tashkin; Harold E. Paulus; Michael R. Irwin; Sarosh J. Motivala; Daniel E. Furst

2006-01-01

454

BifA, a Cyclic-Di-GMP Phosphodiesterase, Inversely Regulates Biofilm Formation and Swarming Motility by Pseudomonas aeruginosa PA14  

Microsoft Academic Search

The intracellular signaling molecule, cyclic-di-GMP (c-di-GMP), has been shown to influence bacterial behaviors, including motility and biofilm formation. We report the identification and characterization of PA4367, a gene involved in regulating surface-associated behaviors in Pseudomonas aeruginosa. The PA4367 gene encodes a protein with an EAL domain, associated with c-di-GMP phosphodiesterase activity, as well as a GGDEF domain, which is associated

Sherry L. Kuchma; Kimberly M. Brothers; Judith H. Merritt; Nicole T. Liberati; Frederick M. Ausubel; George A. O'Toole

2007-01-01

455

The Second Messenger Cyclic Di-GMP Regulates Clostridium difficile Toxin Production by Controlling Expression of sigD  

PubMed Central

The Gram-positive obligate anaerobe Clostridium difficile causes potentially fatal intestinal diseases. How this organism regulates virulence gene expression is poorly understood. In many bacterial species, the second messenger cyclic di-GMP (c-di-GMP) negatively regulates flagellar motility and, in some cases, virulence. c-di-GMP was previously shown to repress motility of C. difficile. Recent evidence indicates that flagellar gene expression is tightly linked with expression of the genes encoding the two C. difficile toxins TcdA and TcdB, which are key virulence factors for this pathogen. Here, the effect of c-di-GMP on expression of the toxin genes tcdA and tcdB was determined, and the mechanism connecting flagellar and toxin gene expressions was examined. In C. difficile, increasing c-di-GMP levels reduced the expression levels of tcdA and tcdB, as well as that of tcdR, which encodes an alternative sigma factor that activates tcdA and tcdB expression. We hypothesized that the C. difficile orthologue of the flagellar alternative sigma factor SigD (FliA; ?28) mediates regulation of toxin gene expression in response to c-di-GMP. Indeed, ectopic expression of sigD in C. difficile resulted in increased expression levels of tcdR, tcdA, and tcdB. Furthermore, sigD expression enhanced toxin production and increased the cytopathic effect of C. difficile on cultured fibroblasts. Finally, evidence is provided that SigD directly activates tcdR expression and that SigD cannot activate tcdA or tcdB expression independent of TcdR. Taken together, these data suggest that SigD positively regulates toxin genes in C. difficile and that c-di-GMP can inhibit both motility and toxin production via SigD, making this signaling molecule a key virulence gene regulator in C. difficile.

McKee, Robert W.; Mangalea, Mihnea R.; Purcell, Erin B.; Borchardt, Erin K.

2013-01-01

456

PdeB, a Cyclic Di-GMP-Specific Phosphodiesterase That Regulates Shewanella oneidensis MR-1 Motility and Biofilm Formation  

PubMed Central

Shewanella oneidensis MR-1, a gammaproteobacterium with respiratory versatility, forms biofilms on mineral surfaces through a process controlled by the cyclic dinucleotide messenger c-di-GMP. Cellular concentrations of c-di-GMP are maintained by proteins containing GGDEF and EAL domains, which encode diguanylate cyclases for c-di-GMP synthesis and phosphodiesterases for c-di-GMP hydrolysis, respectively. The S. oneidensis MR-1 genome encodes several GGDEF and EAL domain proteins (50 and 31, respectively), with a significant fraction (?10) predicted to be multidomain (e.g., GGDEF-EAL) enzymes containing an additional Per-Arnt-Sim (PAS) sensor domain. However, the biochemical activities and physiological functions of these multidomain enzymes remain largely unknown. Here, we present genetic and biochemical analyses of a predicted PAS-GGDEF-EAL domain-containing protein, SO0437, here named PdeB. A pdeB deletion mutant exhibited decreased swimming motility and increased biofilm formation under rich growth medium conditions, which was consistent with an increase in intracellular c-di-GMP. A mutation inactivating the EAL domain also produced similar swimming and biofilm phenotypes, indicating that the increase in c-di-GMP was likely due to a loss in phosphodiesterase activity. Therefore, we also examined the enzymatic activity of purified PdeB and found that the protein exhibited phosphodiesterase activity via the EAL domain. No diguanylate cyclase activity was observed. In addition to the motility and biofilm phenotypes, transcriptional profiling by DNA microarray analysis of biofilms of pdeB (in-frame deletion and EAL) mutant cells revealed that expression of genes involved in sulfate uptake and assimilation were repressed. Addition of sulfate to the growth medium resulted in significantly less motile pdeB mutants. Together, these results indicate a link between c-di-GMP metabolism, S. oneidensis MR-1 biofilm development, and sulfate uptake/assimilation.

Chao, Lily; Rakshe, Shauna; Leff, Maija

2013-01-01

457

Synthesis, 1 H-NMR conformational analysis and complexation studies of two di-imidazolyl acetamido p - tert -butylcalix[4]arenes  

Microsoft Academic Search

The synthesis of a new di-imidazolyl-di-methoxy acetamido p-tert-butylcalix[4]arene 4 is reported. 4 has been prepared by reacting the corresponding di-methyl ester di-methoxy derivative with histamine in 1:1 mixture of methanol:\\u000a toluene. The binding properties of 4 towards alkali, alkaline earth, transition (Zn2+, Co2+) and heavy (Pb2+, Cd2+) metals have been investigated along with the complexes stoichiometries. The 1H-NMR spectra of

Najah Cheriaa; Rym Abidi; Jacques Vicens

2008-01-01

458

DarR, a TetR-like Transcriptional Factor, Is a Cyclic Di-AMP-responsive Repressor in Mycobacterium smegmatis*  

PubMed Central

Cyclic dinucleotides, including cyclic di-AMP (c-di-AMP), are known to be ubiquitous second messengers involved in bacterial signal transduction. However, no transcriptional regulator has been characterized as a c-di-AMP receptor/effector to date. In the present study, using a c-di-AMP/transcription factor binding screen, we identified Ms5346, a TetR family regulator in Mycobacterium smegmatis, as a c-di-AMP receptor in bacteria. Ms5346 could specifically bind c-di-AMP with Kd of 2.3 ± 0.5 ?m. Using EMSA and DNase I footprinting assays, c-di-AMP was found to stimulate the DNA binding activity of Ms5346 and to enhance its ability to protect its target DNA sequence. A conserved 14-bp palindromic motif was identified as the DNA-binding site for Ms5346. Further, Ms5346 was found to negatively regulate expression of three target genes including Ms5347 (encoding a major facilitator family transporter), Ms5348 (encoding a medium chain fatty acyl-CoA ligase), and Ms5696 (encoding a cold shock protein, CspA). Ms5346 is the first cyclic di-AMP receptor regulator to be identified in bacteria, and we have designated it as DarR. Our findings enhance our understanding of the function and regulatory mechanism of the second messenger c-di-AMP in bacteria.

Zhang, Lei; Li, Weihui; He, Zheng-Guo

2013-01-01

459

1-(2,3-Di-hydroxy-prop-yl)-4-{2-[4-(di-methyl-amino)-phen-yl]vin-yl}pyridinium chloride  

PubMed Central

The title compound, C18H23N2O2 +·Cl?, crystallizes with two independent cations and anions per cell. Each cation has twofold rotational disorder about the linking vinyl groups but with unequal occupancies [0.963?(5):0.037?(5) and 0.860?(8):0.140?(8)]. The two independent cations are close to being related by an inversion centre but the data does not support the expected centrosymmetric space-group assignment. The conclusion is that the differing rotational disorder has lead to an overall non-centrosymmetric lattice. In the crystal, the mol­ecules pack in layers parallel to (133) and (-13-3), chain-linked with motif C 1 2(7) by the di­hydroxy­propyl O–H?Cl?H–O hydrogen bonds. Other lattice binding is provided by O—H?Cl, C—H?Cl and C—H?N inter­actions.

Gainsford, Graeme J.; Bhuiyan, M. Delower H.; Kay, Andrew J.

2014-01-01

460

E88, a new cyclic-di-GMP class I riboswitch aptamer from Clostridium tetani, has a similar fold to the prototypical class I riboswitch, Vc2, but differentially binds to c-di-GMP analogs.  

PubMed

C-di-GMP has emerged as a ubiquitous second messenger, which regulates the transition between sessile and motile lifestyles and virulence factor expression in many pathogenic bacteria using both RNA riboswitches and protein effectors. We recently showed that two additional class I c-di-GMP riboswitch aptamers (Ct-E88 and Cb-17B) bind c-di-GMP with nanomolar affinity, and that Ct-E88 RNA binds 2'-F-c-di-GMP 422 times less tightly than class I Vc2 RNA. Based on sequence comparison, it was concluded that the global folds of Ct-E88 and Vc2 RNAs were similar and that differences in ligand binding were probably due to differences in binding site architectures. Herein, we utilized EMSA, aptamer sensing spinach modules, SAXS and 1D NMR titration to study the conformational transitions of Ct-E88. We conclude that whereas the global folds of the bound states of Vc2 and Ct-E88 RNAs are similar, the unbound states are different and this could explain differences in ligand affinities between these class I c-di-GMP riboswitches. PMID:24430255

Luo, Yiling; Chen, Bin; Zhou, Jie; Sintim, Herman O; Dayie, T Kwaku

2014-03-01

461

Associations between hazard indices of di-n-butylphthalate and di-2-ethylhexylphthalate exposure and serum reproductive hormone levels among occupationally exposed and unexposed Chinese men.  

PubMed

The knowledge on the dose-response relationships between cumulative phthalate exposure and reproductive hormones in human are lacking. To assess the characteristics of the associations between hazard index (HI) of cumulative di-n-butylphthalate (DBP) and di-2-ethylhexylphthalate (DEHP) exposures and serum concentrations of free testosterone (fT), estradiol, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), we used restricted cubic spline function to characterize the dose-response curves between the HI values and reproductive hormones for 74 male workers occupationally exposed to high levels of DBP and DEHP, and 63 male construction workers as comparison group matched for age and smoking status. The median of HI value was 5.30 for exposed workers, 53.0-fold that of unexposed workers (0.10). 89.2% of exposed workers and 1.6% of unexposed workers have HI over 1.00. We observed a borderline significantly negative association between HI and fT in exposed workers (r=-0.195, p=0.096), but not in unexposed workers. The exposed workers showed inverted long-tailed J-shaped fT and FSH curves, and small changes in the LH curve, whereas unexposed workers had inverted and flattened-S-shaped fT and mirror-S-shaped LH and FSH curves. Both T production and hypothalamo-pituitary-testis (HPT) axis function were damaged in workers with high HI of phthalate exposures. HPT feedback function was activated in workers with both high and low HI, and plays an important role in preventing fT level from further decreasing with a rise in HI. PMID:21790659

Pan, G; Hanaoka, T; Yu, L; Na, J; Yamano, Y; Hara, K; Ichiba, M; Nakadate, T; Kishi, R; Wang, P; Yin, H; Zhang, S; Feng, Y

2011-10-01

462

Deciphering the Mechanism of Defective Interfering RNA (DI RNA) Biogenesis Reveals That a Viral Protein and the DI RNA Act Antagonistically in Virus Infection  

PubMed Central

Potato mop-top virus (PMTV) produces a defective RNA (D RNA) encompassing the 5?-terminal 479 nucleotides (nt) and 3?-terminal 372 nt of RNA-TGB (where TGB is triple gene block). The mechanism that controls D RNA biogenesis and the role of D RNA in virus accumulation was investigated by introducing deletions, insertions, and point mutations into the sequences of the open reading frames (ORFs) of TGB1 and the 8-kilodalton (8K) protein that were identified as required for efficient production of the D RNA. Transient expression of RNA-TGB in the absence of RNA-Rep (which encodes the replicase) did not result in accumulation of D RNA, indicating that its production is dependent on PMTV replication. The D RNA could be eliminated by disrupting a predicted minus-strand stem-loop structure comprising complementary sequences of the 5? TGB1 ORF and the 3? 8K ORF, suggesting intramolecular template switching during positive-strand synthesis as a mechanism for the D RNA biogenesis. Virus accumulation was reduced when the 8K ORF was disrupted but D RNA was produced. Conversely, the virus accumulated at higher titers when the 8K ORF was intact and D RNA production was blocked. These data demonstrate that the D RNA interferes with virus infection and therefore should be referred to as a defective interfering RNA (DI RNA). The 8K protein was shown to be a weak silencing suppressor. This study provides an example of the interplay between a pathogen and its molecular parasite where virus accumulation was differentially regulated by the 8K protein and DI RNA, indicating that they play antagonistic roles and suggesting a mechanism by which the virus can attenuate replication, decreasing viral load and thereby enhancing its efficiency as a parasite.

Lukhovitskaya, Nina I.; Thaduri, Srinivas; Garushyants, Sonya K.; Torrance, Lesley

2013-01-01

463

Focusing the lens of language experience: Perception of Ma'di stops by Greek and English bilinguals and monolinguals  

PubMed Central

Monolingual listeners are constrained by native language experience when categorizing and discriminating unfamiliar non-native contrasts. Are early bilinguals constrained in the same way by their two languages, or do they possess an advantage? Greek–English bilinguals in either Greek or English language mode were compared to monolinguals on categorization and discrimination of Ma'di stop-voicing distinctions that are non-native to both languages. As predicted, English monolinguals categorized Ma'di prevoiced plosive and implosive stops and the coronal voiceless stop as English voiced stops. The Greek monolinguals categorized the Ma'di short-lag voiceless stops as Greek voiceless stops, and the prevoiced implosive stops and the coronal prevoiced stop as Greek voiced stops. Ma'di prenasalized stops were uncategorized. Greek monolinguals discriminated the non-native voiced-voiceless contrasts very well, whereas the English monolinguals did poorly. Bilinguals were given all oral and written instructions either in English or in Greek (language mode manipulation). Each language mode subgroup categorized Ma'di stop-voicing comparably to the corresponding monolingual group. However, the bilinguals’ discrimination was unaffected by language mode: both subgroups performed intermediate to the monolinguals for the prevoiced-voiceless contrast. Thus, bilinguals do not possess an advantage for unfamiliar non-native contrasts, but are nonetheless uniquely configured language users, differing from either monolingual group.

Antoniou, Mark; Best, Catherine T.; Tyler, Michael D.

2013-01-01

464

Focusing the lens of language experience: perception of Ma'di stops by Greek and English bilinguals and monolinguals.  

PubMed

Monolingual listeners are constrained by native language experience when categorizing and discriminating unfamiliar non-native contrasts. Are early bilinguals constrained in the same way by their two languages, or do they possess an advantage? Greek-English bilinguals in either Greek or English language mode were compared to monolinguals on categorization and discrimination of Ma'di stop-voicing distinctions that are non-native to both languages. As predicted, English monolinguals categorized Ma'di prevoiced plosive and implosive stops and the coronal voiceless stop as English voiced stops. The Greek monolinguals categorized the Ma'di short-lag voiceless stops as Greek voiceless stops, and the prevoiced implosive stops and the coronal prevoiced stop as Greek voiced stops. Ma'di prenasalized stops were uncategorized. Greek monolinguals discriminated the non-native voiced-voiceless contrasts very well, whereas the English monolinguals did poorly. Bilinguals were given all oral and written instructions either in English or in Greek (language mode manipulation). Each language mode subgroup categorized Ma'di stop-voicing comparably to the corresponding monolingual group. However, the bilinguals' discrimination was unaffected by language mode: both subgroups performed intermediate to the monolinguals for the prevoiced-voiceless contrast. Thus, bilinguals do not possess an advantage for unfamiliar non-native contrasts, but are nonetheless uniquely configured language users, differing from either monolingual group. PMID:23556605

Antoniou, Mark; Best, Catherine T; Tyler, Michael D

2013-04-01

465

Structural and Functional Analysis of STING Sheds New Light on Cyclic di-GMP Mediated Immune Signaling Mechanism  

PubMed Central

SUMMARY STING is an essential signaling molecule for DNA and cyclic di-GMP (c-di-GMP)-mediated type I interferon (IFN) production via TANK-binding kinase 1 (TBK1) and Interferon regulatory factor 3 (IRF3) pathway. It contains an N-terminal transmembrane region and a cytosolic C-terminal domain (CTD). Here, we describe crystal structures of STING CTD alone and complexed with c-di-GMP in a unique binding mode. The strictly conserved AA153-173 region was shown to be cytosolic and participated in dimerization via hydrophobic interactions. The STING CTD functions as a dimer and the dimerization was independent of post-translational modifications. Binding of c-di-GMP enhanced interaction of a shorter construct of STING CTD (residues 139-344) with TBK1. This suggests an extra TBK1 binding site, other than Ser358. This study provides a glimpse into the unique architecture of STING and sheds new light on the mechanism of c-di-GMP-mediated TBK1 signaling.

Ouyang, Songying; Song, Xianqiang; Wang, Yaya; Ru, Heng; Shaw, Neil; Jiang, Yan; Niu, Fengfeng; Zhu, Yanping; Qiu, Weicheng; Parvatiyar, Kislay; Li, Yang; Zhang, Rongguang; Cheng, Genhong; Liu, Zhi-Jie

2012-01-01

466

Specific Control of Pseudomonas aeruginosa Surface-Associated Behaviors by Two c-di-GMP Diguanylate Cyclases  

PubMed Central

The signaling nucleotide cyclic diguanylate (c-di-GMP) regulates the transition between motile and sessile growth in a wide range of bacteria. Understanding how microbes control c-di-GMP metabolism to activate specific pathways is complicated by the apparent multifold redundancy of enzymes that synthesize and degrade this dinucleotide, and several models have been proposed to explain how bacteria coordinate the actions of these many enzymes. Here we report the identification of a diguanylate cyclase (DGC), RoeA, of Pseudomonas aeruginosa that promotes the production of extracellular polysaccharide (EPS) and contributes to biofilm formation, that is, the transition from planktonic to surface-dwelling cells. Our studies reveal that RoeA and the previously described DGC SadC make distinct contributions to biofilm formation, controlling polysaccharide production and flagellar motility, respectively. Measurement of total cellular levels of c-di-GMP in ?roeA and ?sadC mutants in two different genetic backgrounds revealed no correlation between levels of c-di-GMP and the observed phenotypic output with regard to swarming motility and EPS production. Our data strongly argue against a model wherein changes in total levels of c-di-GMP can account for the specific surface-related phenotypes of P. aeruginosa.

Merritt, Judith H.; Ha, Dae-Gon; Cowles, Kimberly N.; Lu, Wenyun; Morales, Diana K.; Rabinowitz, Joshua; Gitai, Zemer; O'Toole, George A.

2010-01-01

467

Construction of the new polarised hot neutrons single-crystal diffractometer POLI-HEiDi at FRM-II  

NASA Astrophysics Data System (ADS)

A new hot neutrons single-crystal diffractometer for magnetic structure investigations with polarised neutrons is under construction now at FRM-II near Munich. The problems by implementing the polarised neutron option on the existing instrument HEiDi lead to the decision to build a parallel instrument especially designed for this purpose, called Polarisation Investigator-HEiDi (POLI-HEiDi). Both options, zero field for spher