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Longer Ones (longer + ones)

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Chemistry	40%

Selected Abstracts

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2010
Richard Knochenmuss
Abstract Molecular dynamics simulations of matrix-assisted laser desorption/ionization were carried out to investigate laser pulse width and fluence effects on primary and secondary ionization process. At the same fluence, short (35 or 350 ps) pulses lead to much higher initial pressures and ion concentrations than longer ones (3 ns), but these differences do not persist because the system relaxes toward local thermal equilibrium on a nanosecond timescale. Higher fluences accentuate the initial disparities, but downstream differences are not substantial. Axial velocities of ions and neutrals are found to span a wide range, and be fluence dependent. Total ion yield is only weakly dependent on pulse width, and consistent with experimental estimates. Secondary reactions of matrix cations with analyte neutrals are efficient even though analyte ions are ablated in clusters of matrix. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Long membrane helices and short loops predicted less accurately

PROTEIN SCIENCE, Issue 12 2002
Chien Peter Chen
3D, three-dimensional; DSSP, program assigning secondary structure (Kabsch and Sander 1983); HMM, hidden Markov model; PDB, Protein Data Bank of experimentally determined 3D structures of proteins (Bernstein et al. 1977; Berman et al. 2000); SWISS-PROT, database of protein sequences (Bairoch and Apweiler 2000); TM, transmembrane; TMH, transmembrane helix Abstract Low-resolution experiments suggest that most membrane helices span over 17,25 residues and that most loops between two helices are longer than 15 residues. Both constraints have been used explicitly in the development of prediction methods. Here, we compared the largest possible sequence,unique data sets from high- and low-resolution experiments. For the high-resolution data, we found that only half of the helices fall into the expected length interval and that half of the loops were shorter than 10 residues. We compared the accuracy of detecting short loops and long helices for 28 advanced and simple prediction methods: All methods predicted short loops less accurately than longer ones. In particular, loops shorter than 7 residues appeared to be very difficult to detect by current methods. Similarly, all methods tended to be more accurate for longer than for shorter helices. However, helices with more than 32 residues were predicted less accurately than all other helices. Our findings may suggest particular strategies for improving predictions of membrane helices. [source]

Analysis of BRCA1 and BRCA2 in breast and breast/ovarian cancer families shows population substructure in the Iberian peninsula

ANNALS OF HUMAN GENETICS, Issue 1 2002
A. VEGA
An estimated 5,10% of all breast and ovarian cancers are due to an inherited predisposition, representing a rather large number of patients. In Spain 1/13,1/14 women will be diagnosed with breast cancer during their lifetime. Two major breast cancer genes, BRCA1 and BRCA2, have been identified. To date, several hundred pathogenic mutations in these two genes have been published or reported to the Breast Cancer Information Core, BIC database (http://www.nhgri.nih.gov/Intramural_research_Labtransfer/Bic/index.html). In the present study, 30 Spanish breast and breast/ovarian cancer families (29 from Galicia, NW Spain, and 1 from Catalonia, NE Spain) were screened for mutations in the BRCA1 and BRCA2 genes. The analysis of these genes was carried out by SSCP for shorter exons and direct sequencing in the case of longer ones. Mutations were found in 8 of the 30 families studied (26.66%). It is important to note that all mutations were detected within the BRCA1 gene: 330 A>G, 910_913delGTTC, 2121 C>T, 3958_3962delCTCAGinsAGGC, and 5530 T>A. The BRCA1 330 A>G mutation was found in four unrelated families and accounted for 50% of all identified mutations. [source]

Dental implants placement in conjunction with osteotome sinus floor elevation: a 12-year life-table analysis from a prospective study on 588 ITI®implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2006
Nicola Ferrigno
Abstract Objectives: The purpose of this prospective study was to evaluate the clinical success of placing ITI dental implants in the posterior maxilla using the osteotome technique. Material and methods: All implants were placed following a one-stage protocol (elevating the sinus floor and placing the implant at the same time). Five hundred and eighty-eight implants were placed in 323 consecutive patients with a residual vertical height of bone under the sinus ranging from 6 to 9 mm. The mean observation follow-up period was 59.7 months (with a range of 12,144 months). This prospective study not only calculated the 12-year cumulative survival and success rates for 588 implants by life-table analysis but also the cumulative success rates for implant subgroups divided per implant length and the percentage of sinus membrane perforation were evaluated. Results: The 12-year cumulative survival and success rates were 94.8% and 90.8%, respectively. The analysis of implant subgroups showed slightly more favourable cumulative success rates for 12 mm long implants (93.4%) compared with 10 and 8 mm long implants (90.5% and 88.9%, respectively). During the study period, only 13 perforations of the Schneiderian membrane were detected with a perforation rate of 2.2% (13 perforations/601 treated sites). Ten perforations out of 13 were caused during the first half of the study period and of these, seven were detected during the first 3 years of this prospective study. Conclusion: Based on the results and within the limits of the present study, it can be concluded that ITI implant placement in conjunction with osteotome sinus floor elevation represents a safe modality of treating the posterior maxilla in areas with reduced bone height subjacent to the sinus as survival and success rates were maintained above 90% for a mean observation period of ,60 months. Shorter implants (8 mm implants) did not significantly fail more than longer ones (10 and 12 mm implants): the differences were small compared with the number of events; hence, no statistical conclusion could be drawn. But, from the clinical point of view, the predictable use of short implants in conjunction with osteotome sinus floor elevation may reduce the indication for complex invasive procedures like sinus lift and bone grafting procedures. [source]

A 7-year life table analysis from a prospective study on ITI implants with special emphasis on the use of short implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2004
Results from a private practice
Abstract: This paper reports on a 7-year life table analysis on ITI titanium plasma-sprayed (TPS) and sandblasted and etched (SLA) implants placed in a private practice and loaded for at least 1 year. In 236 patients, 528 (264 TPS and 264 SLA) implants were placed, 351 (66.5%) implants rehabilitated the posterior region and 71.1% implants were ,11 mm. In the posterior mandible and maxilla, the mean implant length was 9.90 and 9.74 mm respectively. Implant length was determined through standard radiographs only. Increase of the number of implants or reduction of the width or the length of the rehabilitations was not specifically sought for the shorter implants. One hundred and twenty-two SLA implants were loaded within 63 days. All early loaded SLA implants resisted the applied 35 N cm without rotation or pain. Three implants failed, one early and two late failures, all were SLA implants placed in the mandible. Shorter implants did not fail more than longer ones. The cumulative success rate was 99.40%. The predictable use of short implants supporting single crowns and small fixed partial dentures of 2,4 units supported by two to three implants permitted (1) restricting the need for sophisticated and expensive presurgical procedures aimed to determine precisely the available bone height by computerized radiographic methods, (2) the placement of prosthetically driven restoration instead of surgically driven ones, (3) reducing the indications span for complex invasive procedures like sinus lift and bone grafting procedures, (4) facilitating the surgery, without attempting to place the longest implant and (5) avoiding the occurrence of sensation disturbance. The safe use of short implants in a private practice should make implant therapy simpler and accessible to a higher number of patients and practitioners. Résumé Ce manuscript rapporte une analyse sur sept ans d'implants ITI® TPS et SLA placés dans un cabinet privé et chargés pendant au moins une année. Chez 236 patients, 528 implants (264 TPS et 264 SLA) ont été placés, 351 (66,5%) d'entre eux pour reconstruire la région postérieure et 71,1 étaient ,11 mm. Dans les parties postérieures de la mandibule et du maxillaire la longueur implantaire moyenne était respectivement de 9,90 et 9,74 mm. La longueur de l'implant était déterminée à partir uniquement de radiographies standards. L'augmentation du nombre d'implants ou la réduction de la largeur ou la longueur des reconstructions n'étaient pas spécifiquement recherchées pour les implants les plus courts. Cent vingt-deux implants SLA ont été mis en charge avant 63 jours. Tous les implants SLA avec mise en charge précoce ont resistéà la force de 35 Ncm appliquée sans rotation ni douleur. Trois implants ont échoué: 1) de manière précoce et 2) plus tard, tous étaient des implants SLA placés dans la mandibule. Les implants les plus courts n'avaient pas davantage d'échec que les plus longs. Le taux de succès cumulatif était de 99,40%. L'utilisation prévisible des implants courts portant des couronnes uniques et des petites prothèses fixées de deux à quatre unités supportées par deux à trois implants permettait 1) de réduire la nécessité de processus préchirurgicaux sophistiqué et cher visant ,a d"terminer précisemnentla hauteur osseuse disponible par des méthodes radiographiques avec ordinateur, 2) le placement de restaurations axées sur la prothèse plutôt que sur la chirurgie, 3) de diminuer la portée des indications des processus invasifs complexes comme l'épaississement du plancher buccal et les processus de greffe osseuse, 4) de faciliter la chirurgie sans essayer de placer l'implant le plus long, 5) d'éviter l'apparition de troubles de sensation. L'utilisation s,re d'implants court dans une pratique privée pourrait rendre la thérapie plus simple et accessible à un polus grand nombre de patients et de praticiens. Zusammenfassung Diese Arbeit berichtet über eine 7 Jahre Life Time Analyse von ITI TPS und SLA Implantaten, welche in einer Privatpraxis gesetzt wurden und für mindestens 1 Jahr unter Belastung standen. Bei 236 Patienten wurden 528 Implantate (264 TPS und 264 SLA) eingesetzt, 351 Implantate (66.5%) dienten der Wiederherstellung der posterioren Region und 71.1% der Implantate waren 11 mm lang. In der posterioren Mandibula bzw. Maxilla betrug die mittlere Implantatlänge 9.9 bzw. 9.74 mm. Die Implantatlänge wurde nur auf Standardröntgenbildern bestimmt. Bei Rekonstruktionen mit kurzen Implantaten wurden nicht speziell mehr Implantate verwendet oder die Breite oder die Länge der Rekonstruktionen reduziert. 122 SLA Implantate wurden innerhalb von 63 Tagen belastet. Alle frühbelasteten SLA Implantate widerstanden den applizierten 35Ncm ohne Rotation oder Schmerzen. 3 Implantate zeigten Misserfolge, einen Früh- und 2 Spätmisserfolge. Es handelte sich dabei ausschliesslich um SLA Implantate, welche im Unterkiefer eingesetzt worden waren. Kurze Implantate zeigten nicht mehr Misserfolge als lange. Die kumulative Erfolgsrate betrug 99.4%. Die Verwendung von kurzen Implantaten, welche Einzelkronen und kleine festsitzende Brücken mit 2,4 Einheiten auf 2,3 Implantanten trugen, erlaubte, 1) die Notwendigkeit von komplizierten und teuren prächirurgischen Abklärungen zur genauen Bestimmung der zur Verfügung stehenden Knochenhöhe durch computerisierte radiologische Methoden zu beschränken, 2) die Platzierung von prothetisch diktierten Rekonstruktionen anstelle von chirurgisch diktierten Rekonstruktionen, 3) eine Reduktion der Indikationsbreite von komplexen invasiven Prozeduren wie Sinuslift und Knochentransplantationen, 4) eine Erleichterung der Chirurgie indem nicht ein möglichst langes Implantat gesetzt werden musste, 5) das Auftreten von Sensibilitätsstörungen zu vermeiden. Die sichere Verwendung von kurzen Implantaten in einer Privatpraxis sollte die Implantattherapie einfacher machen. Dadurch sollte die Behandlung mit Implantaten einer grösseren Anzahl Patienten und Praktikern zugänglich werden. Resumen Este estudio informa sobre un análisis de un cuadro de vida de implantes ITI TPS y SLA colocados en una consulta privada y cargados durante al menos un año. Se colocaron 528 implantes (264 TPS y 264 SLA) en 236 pacientes, 351 implantes (66.5%) rehabilitaron el maxilar posterior y el 71.1% de los implantes fueron ,11 mm. La longitud media de los implantes en la mandíbula posterior y el maxilar fue de 9,90 y 9.74 mm respectivamente. La longitud del implante se determinó solamente a través de radiografías. No se buscaron específicamente incrementos en el número de implantes o reducción en la anchura o longitud de las rehabilitaciones para los implantes cortos. Se cargaron 122 implantes dentro de los 63 días. Todos los implantes SLA cargados tempranamente resistieron la fuerza de 35 Ncm aplicada sin rotación ni dolor. 3 implantes fracasaron, uno tempranamente y 2 tardíos, todos fueron implantes SLA colocados en la mandíbula. Los implantes mas cortos no fracasaron más que los implantes largos. El índice acumulativo de éxito fue del 99.4%. El uso predecible de implantes cortos soportando coronas unitarias y pequeñas prótesis fijas parciales de 2,4 unidades soportadas por 2,3 implantes permitieron, 1) restringir la necesidad de procedimientos quirúrgicos sofisticados y costosos con la intención de determinar con precisión la altura de hueso disponible por medio de métodos de radiografías computarizadas, 2) la colocación de restauraciones orientadas prosteticamente en vez de quirúrgicamente, 3) reducir el abanico de indicaciones para procedimientos complejos invasivos tales como procedimientos de elevación del seno e injertos, 4) facilitar la cirugía, sin intentar colocar el implante mas largo, 5) evitar la aparición de sensación de molestia. El uso seguro de implantes cortos en una consulta privada debería hacer el tratamiento de implantes mas simple y accesible para un mayor número de pacientes y profesionales. [source]