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Acquisition System (acquisition + system)
Kinds of Acquisition System Selected AbstractsAn automated pottery archival and reconstruction systemCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3 2003Martin Kampel Abstract Motivated by the current requirements of archaeologists, we are developing an automated archival system for archaeological classification and reconstruction of ceramics. Our system uses the profile of an archaeological fragment, which is the cross-section of the fragment in the direction of the rotational axis of symmetry, to classify and reconstruct it virtually. Ceramic fragments are recorded automatically by a 3D measurement system based on structured (coded) light. The input data for the estimation of the profile is a set of points produced by the acquisition system. By registering the front and the back views of the fragment the profile is computed and measurements like diameter, area percentage of the complete vessel, height and width are derived automatically. We demonstrate the method and give results on synthetic and real data. Copyright © 2003 John Wiley & Sons, Ltd. [source] Entities and frequency of neonatal diabetes: data from the diabetes documentation and quality management system (DPV)DIABETIC MEDICINE, Issue 6 2010J. Grulich-Henn Diabet. Med. 27, 709,712 (2010) Abstract Aims, The aim of this study was to elucidate the entities and the frequency of neonatal diabetes mellitus (NDM) in a large representative database for paediatric diabetes patients in Germany and Austria. Methods, Based on the continuous diabetes data acquisition system for prospective surveillance (DPV), which includes 51 587 patients with onset of diabetes before the age of 18 years from 299 centres in Germany and Austria, we searched for patients with onset of diabetes mellitus in the first 6 months of life. Results, Ninety patients were identified, comprising 0.17% of all paediatric cases in the DPV registry. This represented an incidence of approximately one case in 89 000 live births in Germany. A monogenic basis for NDM was established in 30 subjects (seven UPD6, 10 KCNJ11, seven ABCC8, two FOXP3, two PDX1, one INS, one EIF2AK3). Pancreatic hypoplasia or agenesis was reported in 10 patients and seven subjects were classified as having Type 1 diabetes by their centres. Transient neonatal diabetes (TNDM) accounted for approximately 10% of all cases with NDM. No aetiology was defined in 41 subjects, which may reflect incomplete genetic testing or novel genetic aetiologies. Conclusion, Based on a large database, we identified a higher rate of NDM in Germany than has been reported previously. Full molecular genetic testing should be performed in all patients diagnosed before 6 months of age. [source] The horse-racetrack interface: a preliminary study on the effect of shoeing on impact trauma using a novel wireless data acquisition systemEQUINE VETERINARY JOURNAL, Issue 7 2006B. L. DALLAP SCHAER Summary Reasons for performing study: There is a need to determine accelerations acting on the equine hoof under field conditions in order to better assess the risks for orthopaedic health associated with shoeing practices and/or surface conditions. Objectives: To measure the acceleration profiles generated in Thoroughbred racehorses exercising at high speeds over dirt racetracks and specifically to evaluate the effect of a toe grab shoe compared to a flat racing plate, using a newly developed wireless data acquisition system (WDAS). Methods: Four Thoroughbred racehorses in training and racing were used. Based on previous trials, each horse served as its own control for speed trials, with shoe type as variable. Horses were evaluated at speeds ranging from 12.0,17.3 m/sec. Impact accelerations, acceleration on break over and take-off, and temporal stride parameters were calculated. Impact injury scores were also determined, using peak accelerations and the time over which they occurred. Results: Recorded accelerations for the resultant vector (all horses all speeds) calculated from triaxial accelerometers ranged 96.3,251.1 g, depending on the phase of the impact event. An association was observed between shoe type and change in acceleration in individual horses, with 2 horses having increased g on initial impact with toe grab shoes in place. In the final impact phase, one horse had an increase of 110 g while wearing toe grab shoes. Increased accelerations were also observed on break over in 2 horses while wearing toe grab shoes. Conclusions: Shoe type may change impact accelerations significantly in an individual horse and could represent increased risk for injury. Further work is needed to determine if trends exist across a population. Potential relevance: The WDAS could be used for performance evaluation in individual horses to evaluate any component of the horse-performance surface interface, with the goal of minimising risk and optimising performance. [source] Use of low frequencies for sub-basalt imagingGEOPHYSICAL PROSPECTING, Issue 3 2003Anton Ziolkowski ABSTRACT Many prospective passive ocean margins are covered by large areas of basalts. These basalts are often extremely heterogeneous and scatter the seismic energy of the conventional seismic reflection system so that it becomes difficult to obtain information on deeper reflectors. Since high frequencies are scattered more than low frequencies, we argue that the acquisition system for sub-basalt targets should be modified to emphasize the low frequencies, using much larger airguns, and towing the source and receivers at about 20 m depth. In the summer of 2001 we obtained seismic reflection data over basalt in the northeast Atlantic using a system modified to enhance the low-frequency energy. These new data show deep reflections that are not visible on lines shot in the same places with a conventional system. [source] Computational energy analysis of an innovative isothermal chamber for testing of the special equipment used in the transport of perishable productsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2004S. K. Chatzidakis Abstract This paper describes an improved numerical simulation study of an isothermal chamber recently constructed at Zografou Campus of the National Technical University of Athens (NTUA) for the testing of special equipment used for transporting perishable foodstuffs in accordance with the United Nations ATP agreement. Using a transient finite difference model, a simulation is developed for a modern ATP test chamber and a typical specimen refrigerated vehicle to be tested. The simulation results are compared to experimental measurements taken under real conditions by a data acquisition system and a refrigerated semi-trailer as specimen. Proportional,integral control is employed for the regulation of the cooling and heating system. The impact of various parameters on the time required to reach the set-point temperature (tset) is investigated and the energy consumption is simulated for a period of 22 h. In particular, the impact of specimen insulation thickness and the thickness of the chamber insulation floor are considered in detail. The total energy consumption increases by approximately 16% when the concrete floor layer thickness is increased from 8 to 16 cm for typical initial conditions and desired chamber and specimen temperatures of 32.5 and 7.5°C, respectively. Using a floor insulation of 6 cm extruded heavy strain-resistant polystyrene reduces the energy consumption by at least 13%. Specimen insulation thickness increase from U -value of 0.35 W m,2 K to 0.75 W m,2 K result to an increase in energy consumption by a percentage of 28%. Thermal capacity, temperature of car body and specimen dimensions are also treated as variables that affect the total duration of an ATP test and its total energy consumption. Copyright © 2004 John Wiley & Sons, Ltd. [source] Modeling Cooking Time to Inactivate Salmonella in Chicken Leg Quarters Cooked in an Air,Steam Impingement OvenJOURNAL OF FOOD SCIENCE, Issue 5 2006Tareq M. Osaili ABSTRACT:, Inadequate cooking of poultry products may lead to human foodborne infections. The use of mathematical models that describe heat transfer during cooking of chicken leg quarters may help in developing safer food products and minimizing time for cooking. The objective of this study was to develop regression models that predict cooking time required to reach internal temperatures of 71.1, 73.9, 76.7, and 82.2 °C in chicken leg quarters. Samples that had different weights, thicknesses, and initial internal temperatures were cooked in an air,steam impingement oven at temperature of 232.2 °C, humidity of 60%, and air velocity of 1.4 m/min. A thermocouple probe (type K) connected with a data acquisition system was inserted into the coldest point of each chicken leg quarter. Samples were cooked until they reached an internal temperature higher than 82.2 °C. The collected data of each sample in the data acquisition system were used to develop regression models that depend on sample weight, thickness, and initial temperature in predicting cooking times. Sample weight, thickness, and initial internal temperature had significant effects on the cooking time. The results of these models would be helpful for ready-to-eat poultry processors to meet lethality performance standards, and ensuring the safety and quality of skin on, bone in chicken leg quarters cooked via air,steam impingement ovens. [source] A new ferrous iron-uptake transporter, EfeU (YcdN), from Escherichia coliMOLECULAR MICROBIOLOGY, Issue 1 2006Cornelia Große Summary Escherichia coli possesses multiple routes for iron uptake. Here we present EfeU (YcdN), a novel iron acquisition system of E. coli strain Nissle 1917. Laboratory strains of E. coli such as K12 lack a functional (efeU) ycdN gene caused by a frameshift mutation. EfeU, a member of the oxidase-dependent iron transporters (OFeT), is a homologue of the iron permease Ftr1p from yeast. The ycdN gene is part of the ycdNOB tricistronic operon which is expressed in response to iron deprivation in a Fur-dependent manner. Expression of efeU resulted in improved growth of an E. coli mutant lacking all known iron-uptake systems and mediated increased iron uptake into cells. Furthermore, the presence of other divalent metal cations did not impair growth of strains expressing efeU. The EfeU protein functioned as ferrous iron permease in proteoliposomes in vitro. Topology analysis indicated that EfeU is an integral cytoplasmic membrane protein exhibiting seven transmembrane helices. Two REXXE motifs within transmembrane helices of OFeT family members are implicated in iron translocation. Site-directed mutagenesis of each REGLE motif of EfeU diminished iron uptake in vivo and growth yield. In vitro the EfeU variant protein with an altered first REGLE motif was impaired in iron permeation, whereas activity of the EfeU variant with a mutation in the second motif was similar to the wild-type protein. [source] Adaptation of the brucellae to their intracellular nicheMOLECULAR MICROBIOLOGY, Issue 3 2004R. Martin Roop II Summary Members of the bacterial genus Brucella are facultative intracellular pathogens that reside predominantly within membrane-bound compartments within two host cell types, macrophages and placental trophoblasts. Within macrophages, the brucellae route themselves to an intracellular compartment that is favourable for survival and replication, and they also appear to be well-adapted from a physiological standpoint to withstand the environmental conditions encountered during prolonged residence in this intracellular niche. Much less is known about the interactions of the Brucella with placental trophoblasts, but experimental evidence suggests that these bacteria use an iron acquisition system to support extensive intracellular replication within these host cells that is not required for survival and replication in host macrophages. Thus, it appears that the brucellae rely upon the products of distinct subsets of genes to adapt successfully to the environmental conditions encountered within the two cell types within which they reside in their mammalian hosts. [source] Characterization of HasB, a Serratia marcescens TonB-like protein specifically involved in the haemophore-dependent haem acquisition systemMOLECULAR MICROBIOLOGY, Issue 4 2001Annick Paquelin In Gram-negative bacteria, the TonB,ExbB,ExbD inner membrane multiprotein complex is required for active transport of diverse molecules through the outer membrane. We present evidence that Serratia marcescens, like several other Gram-negative bacteria, has two TonB proteins: the previously characterized TonBSM, and also HasB, a newly identified component of the has operon that encodes a haemophore-dependent haem acquisition system. This system involves a soluble extracellular protein (the HasA haemophore) that acquires free or haemoprotein-bound haem and presents it to a specific outer membrane haemophore receptor (HasR). TonBSM and HasB are significantly similar and can replace each other for haem acquisition. However, TonBSM, but not HasB, mediates iron acquisition from iron sources other than haem and haemoproteins, showing that HasB and TonBSM only display partial redundancy. The reconstitution in Escherichia coli of the S. marcescens Has system demonstrated that haem uptake is dependent on the E. coli ExbB, ExbD and TonB proteins and that HasB is non-functional in E. coli. Nevertheless, a mutation in the HasB transmembrane anchor domain allows it to replace TonBEC for haem acquisition. As the change affects a domain involved in specific TonBEC,ExbBEC interactions, HasB may be unable to interact with ExbBEC, and the HasB mutation may allow this interaction. In E. coli, the HasB mutant protein was functional for haem uptake but could not complement the other TonBEC -dependent functions, such as iron siderophore acquisition, and phage DNA and colicin uptake. Our findings support the emerging hypothesis that TonB homologues are widespread in bacteria, where they may have specific functions in receptor,ligand uptake systems. [source] Tool command language automation of the modular ion cyclotron data acquisition system (MIDAS) for data-dependent tandem Fourier transform ion cyclotron resonance mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2003Michael A. Freitas This manuscript describes the addition of data-dependent automation to the modular ion cyclotron resonance data acquisition system (MIDAS). The automation is made possible by developments and incorporation of a tool command language (Tcl) interpreter for automated acquisition. To accomplish the automation, real-time generation of excitation waveforms and scriptable data post-processing has been implemented into the MIDAS source code. In addition a new excitation event has also been added to allow for run-time generation of a single notch stored waveform inverse Fourier transform (SWIFT) excitation event. Examples of these new features and discussion of their enhancement to the existing data station are presented. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effects of low dose dexamethasone treatment on basal cardiovascular and endocrine function in fetal sheep during late gestationTHE JOURNAL OF PHYSIOLOGY, Issue 2 2002Andrew J. W. Fletcher This study investigated the effects on ovine fetal basal cardiovascular and endocrine functions of fetal intravenous dexamethasone treatment, resulting in circulating concentrations that were one-fifth of the values measured clinically in human infants following maternal antenatal glucocorticoid therapy. Between 117-120 days gestation (dGA; term: ca 145 dGA), 26 Welsh Mountain sheep fetuses were surgically prepared under general anaesthesia with vascular catheters and a Transonic flow probe positioned around a femoral artery. At 125 ± 1 dGA, fetuses were infused with dexamethasone (2.06 ± 0.13 ,g kg,1 h,1i.v.; n= 13) or saline (n= 13) for 48 h. Daily fetal arterial blood samples were taken and cardiovascular data were recorded continuously (data acquisition system). Pressor, vasoconstrictor and chronotropic responses to exogenously administered doses of phenylephrine, angiotensin II and arginine vasopressin (AVP) were determined at 124 ± 1 (pre-infusion), 126 ± 1 (during infusion) and 128 ± 1 (post-infusion) dGA. Fetal cardiac baroreflex curves were constructed using peak pressor and heart rate responses to phenylephrine. Dexamethasone treatment elevated fetal mean arterial blood pressure by 8.1 ± 1.0 mmHg (P < 0.05), increased femoral vascular resistance by 0.65 ± 0.12 mmHg (ml min,1),1 (P < 0.05), depressed plasma noradrenaline concentrations and produced a shift in set-point, but not sensitivity, of the cardiac baroreflex (P < 0.05). Elevations in fetal arterial blood pressure, but not femoral vascular resistance and the shift in baroreflex set-point, persisted at 48 h following dexamethasone treatment. By 48 h following dexamethasone infusion, basal plasma noradrenaline concentration was restored, whilst plasma adrenaline and neuropeptide Y (NPY) concentrations were enhanced, compared with controls (P < 0.05). Fetal dexamethasone treatment did not alter the fetal pressor or femoral vasoconstrictor responses to adrenergic, vasopressinergic or angiotensinergic agonists. These data show that fetal treatment with low concentrations of dexamethasone modifies fetal basal cardiovascular and endocrine functions. Depending on the variable measured, these changes may reverse, persist or become enhanced by 48 h following the cessation of treatment. [source] Fresh-frozen vs. embalmed bone: is it possible to use formalin-fixed human bone for biomechanical experiments on implants?CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2009Ayhan Cömert Abstract Purpose: As formalin is an extremely reactive electrophilic chemical that reacts with tissues, the purpose of this study was to explore whether formalin fixation could potentially alter the mechanical properties of bone tissue and have an effect on the primary stability measurements of implants. Material and methods: ,3.3 × 8 mm, ,4.1 × 8 mm, and ,4.8 × 8 mm implants were placed on sockets prepared into the anterior surface of the radius of two fresh-frozen human cadavers. The insertion torque of each implant was quantified using a strain-gauged torque-wrench connected to a data acquisition system at a sample rate of 10 KHz, and resonance frequency analysis measurements were also undertaken for each implant. The cadavers were then subjected to embalment with 10% formalin for 3 months, and the same experiments were undertaken on the contra lateral radius of the cadavers. Results: The insertion torques before and after chemical fixation were similar for ,3.3 mm (P>0.05), and higher values were obtained for ,4.1 mm and ,4.8 mm implants after chemical fixation (P<0.05). The resonance frequency analysis values before and after chemical fixation were similar for all implants (P>0.05). Conclusions: Implants have higher insertion torque values in formalin-fixed bone than fresh-frozen human bone, but similar implant stability quotients in both cases. The insertion torque technique can detect the difference between formalin-fixed and fresh-frozen human bone, but resonance frequency analysis cannot. [source] Human ex vivo bone tissue strains around immediately loaded implants supporting maxillary overdenturesCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2005vanç Akça Abstract Purpose: To evaluate ex vivo bone tissue strains around maxillary implants supporting immediately loaded bar-retained overdentures. Material and methods: Ninety degree two-element rosette strain gauges were bonded on the labial bone of four ITI® dental implants placed in the maxillary anterior region of four completely edentulous maxilla of fresh human cadavers. The installation torque value (ITV) of each implant was measured by a custom-made torque wrench and resonance frequency analyses (RFAs) were undertaken. A bar-retained overdenture was fabricated for each cadaver, and two miniature load cells were integrated in the first molar region of the overdentures for controlled loading experiments. Strain measurements were performed at a sample rate of 10 kHz and under a maximum load of 100 N, simultaneously monitored from a computer connected to a data acquisition system. Finally, removal torque values (RTVs) of the implants were measured. Results: RFA values did not mirror ITVs, while RTVs of implants were slightly lower than the ITVs. Any correlation could not be obtained between RFA values and ITVs or RTVs. Maximum strains around loaded implants ranged between ,100 and ,550 ,, under 25,100 N. The axial and lateral strain values of posterior implants of both sides were higher than those of anterior implants under all loads (P<0.05). Conclusion: Because occlusal forces in humans tend to decrease because of age-related factors, maximum strains around immediately loaded implants supporting maxillary overdentures fall within physiologic levels. Résumé Le but de cette étude a été d'évaluer les tensions du tissu osseux ex vivo autour d'implants maxillaires portant des prothèses amovibles retenues sur une barre placée immédiatement après l'insertion des implants. Deux jauges de force en rosette à 90° ont été attachées au côté lingual de l'os de quatre implants dentaires ITI® placés dans la région antérieure du maxillaire de quatre cadavres humains frais aux maxillaires édentées. La valeur du couple de torsion lors de l'installation (ITV) de chaque implant a été mesurée par un couple fabriqué et des analyses de fréquence de résonnance (RFA) ont été faites. Une prothèse retenue par une barre a été fabriquée pour chaque cadavre et deux cellules de charge miniatures ont été intégrées dans la région de la première molaire de ces prothèses pour les expériences de charge contrôlées. Les mesures de force ont été effectuées à un taux d'échantillonnage de 10 kHz et sous une charge maximale de 100 N, suivies simultanément par un ordinateur connectéà un système d'acquisition de données. Finalement les valeurs des couples de torsion à l'enlèvement (RTV) des implants ont été mesurées. Les valeurs RFA n'étaient pas en ligne avec les ITV tandis que les RTV des implants étaient légèrement inférieurs aux ITV. Aucune corrélation n'a pûêtre établie entre les valeurs RFA et ITV ou RTV. Les forces maximales autour des implants chargés s'étalaient de ,100 ,e à,550 ,e sous 25 N à 100 N. Les valeurs des forces axiales et latérales des implants postérieurs des deux côtés étaient supérieures à celles des implants antérieurs sous toutes les charges (P<0.05). Zusammenfassung Ziel: Es war das Ziel dieser Arbeit, an bis vor kurzem vitalen Knochengewebe Spannungen um Oberkieferimplantate zu untersuchen, welche sofortbelastete und stegverankerte Hybridprothesen tragen. Material und Methoden: Auf den labialen Knochen von vier ITI-Implantaten in der vorderen Region des zahnlosen Oberkiefers von vier frisch verstorbenen Menschen klebte man Dehnmessinstrumente an. Man mass den Wert der Eindrehkraft (ITV) jedes einzelnen Implantates mit einem handelsblichen Drehmomentschlssel und fhrte eine Resonanzfrequenzanalyse (RFA) durch. Man stellte fr jede Leiche eine stegverankerte Hybridprothese her und man baute in der Region der ersten Molaren zwei kleine Messgerte ein, die kontrollierte Belastungsexperimente erlaubten. Dehnmessungen fhrte man mit einer Frequenz von 10 kHz und einer maximalen Belastung von 100 N durch, simultan aufgezeichnet von einem mit dem Messsystem verbundenen Komputer. Schliesslich mass man auch die Krfte, die es brauchte um die Implantate wieder auszudrehen (RTV). Resultate: Die RFA wiederspiegelte die ITV-Werte nicht, whrenddem die RTV-Werte der Implantate geringfgig tiefer waren als die ITV-Werte. Man konnte weder zwischen der RFA, den ITV-Werten oder den RTV-Werten eine Korrelation herstellen. Die maximalen Dehnungen um die Implantate erreichte Werte zwischen ,100 E und ,550 E bei einer Belastung zwischen 25 N und 100 N. Die axialen und lateralen Dehnkrfte bei posterioren Implantaten waren unter smtlichen getesteten Belastungen beidseits grsser als diejenigen der anterioren Implantate (P<0.05). Resumen Propósito: Evaluar las tensiones del tejido óseo ex vivo alrededor de implantes maxilares soportando sobredentaduras retenidas por barras con carga inmediata. Material y Métodos: Se pegaron dos indicadores de tensión de roseta de dos elementos de 90° en el hueso labial de cuatro implantes dentales ITI® colocados en la región maxilar anterior de cuatro maxilares completamente edéntulos de cadáveres humanos frescos. Se midió el valor del torque de instalación (ITV) de cada implante por medio de una chicharra de torque hecha a medida y se llevó a cabo análisis de frecuencia de resonancia (RFA). Se fabricó una sobredentadura retenida por barras para cada cadáver y se integraron dos células miniatura de carga en la región del primer molar de las sobredentaduras para los experimentos de carga controlada. Se llevaron a cabo mediciones de la tensión a un índice de muestra de 10 kHz y bajo una carga máxima de 100 N, simultáneamente monitorizada desde un ordenador conectado a sistema de adquisición de datos. Finalmente, se midieron los valores del torque de remoción (RTV) de los implantes. Resultados: Los valores de RFA no se reflejaron en los ITVs, mientras que los RTVs de los implantes fueron ligeramente más bajos que los ITVs. No se pudieron obtener correlaciones entre los valores de RFA y los ITVs o RTVE. Las tensiones máximas alrededor de los implantes cargados variaron entre ,100 ,, y ,550 ,, bajo 25 N a 100 N. Los valores de las tensiones axiales y laterales de los implantes posteriores de ambos lados fueron mayores que aquellos implantes anteriores bajo todas las cargas (P<0.05). [source] Data Preparation for Real-time High Quality Rendering of Complex ModelsCOMPUTER GRAPHICS FORUM, Issue 3 2006Reinhard Klein The capability of current 3D acquisition systems to digitize the geometry reflection behaviour of objects as well as the sophisticated application of CAD techniques lead to rapidly growing digital models which pose new challenges for interaction and visualization. Due to the sheer size of the geometry as well as the texture and reflection data which are often in the range of several gigabytes, efficient techniques for analyzing, compressing and rendering are needed. In this talk I will present some of the research we did in our graphics group over the past years motivated by industrial partners in order to automate the data preparation step and allow for real-time high quality rendering e.g. in the context of VR-applications. Strength and limitations of the different techniques will be discussed and future challenges will be identified. The presentation will go along with live demonstrations. [source] Differential expression of Bordetella pertussis iron transport system genes during infectionMOLECULAR MICROBIOLOGY, Issue 1 2008Timothy J. Brickman Summary Temporal expression patterns of the Bordetella pertussis alcaligin, enterobactin and haem iron acquisition systems were examined using alcA,, bfeA, and bhuR,tnpR recombinase fusion strains in a mouse respiratory infection model. The iron systems were differentially expressed in vivo, showing early induction of the alcaligin and enterobactin siderophore systems, and delayed induction of the haem system in a manner consistent with predicted changes in host iron source availability during infection. Previous mixed infection competition studies established the importance of alcaligin and haem utilization for B. pertussis in vivo growth and survival. In this study, the contribution of the enterobactin system to the fitness of B. pertussis was confirmed using wild-type and enterobactin receptor mutant strains in similar competition infection experiments. As a correlate to the in vivo expression studies of B. pertussis iron systems in mice, sera from uninfected and B. pertussis -infected human donors were screened for antibody reactivity with Bordetella iron-repressible cell envelope proteins. Pertussis patient sera recognized multiple iron-repressible proteins including the known outer membrane receptors for alcaligin, enterobactin and haem, supporting the hypothesis that B. pertussis is iron-starved and responds to the presence of diverse iron sources during natural infection. [source] Iron transport and regulation, cell signalling and genomics: lessons from Escherichia coli and PseudomonasMOLECULAR MICROBIOLOGY, Issue 5 2002Paolo Visca Summary A variety of bacterial species secrete and take up chelating compounds that enable acquisition of iron (siderophores). It has become clear that a common feature in regulation of different iron acquisition systems is the involvement of alternative sigma factor proteins of the extracytoplasmic function (ECF) family. Two of these proteins, PvdS from Pseudomonas aeruginosa and FecI from Escherichia coli K-12, have been studied extensively. PvdS directs transcription of genes required for the biosynthesis of a siderophore, pyoverdine, and FecI causes ex-pression of genes for uptake of ferric citrate. FecI forms part of a signalling system that responds to the presence of ferric citrate. Here, we review recent advances in understanding of PvdS and of the Fec signalling system. PvdS and FecI are part of a distinct subfamily of ECF sigma factors involved in iron acquisition and hence named the iron-starvation sigmas. Analysis of microbial genome sequences shows that Fec-like signalling systems are present in a wide range of species and many such systems may be present in a single species. The availability of tools for large-scale genome analysis is likely to lead to rapid advances in our understanding of this expanding family of proteins. [source] Three-dimensional surface acquisition systems for the study of facial morphology and their application to maxillofacial surgeryTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 2 2007Chung How Kau Abstract Background There has been a growing interest in three-dimensional (3D) surface imaging devices over the last few years. Methods This comprehensive review discusses the various emerging technologies in this field of 3D imaging and applies the use of technology to oral and maxillofacial imaging. Results The paper shows that there is increased awareness and application of technology to the field. Conclusion 3D surface acquisition technology is improving at a rapid pace and has a place in oral and maxillofacial surgery. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||