bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Design of Free Standing Exhaust Stacks for Offshore Applications
Authors: Allison I. M. , Steel A. C. 
Published: March 2015

This paper describes the methods developed to optimize the mechanical design of a free standing exhaust stack and its supporting structure. These particular methods have been used for the design of three gas turbine exhaust systems on a UK sector offshore platform currently under construction. The driving force behind the choice of a free standing stack was to save weight and therefore cost. The move towards the development of marginal fields in deeper waters will only increase the need for lighter, and therefore more cost effective design solutions.
Although national standards which cover the basic design philosophy are available, these have serious limitations when applied to this type of structure. The aim of this paper is to demonstrate how the limitations may be overcome by undertaking fundamental design analysis, and also to indicate those critical areas which demand special consideration. The detailed design analysis presented here considers the possibility of failure due to local instability, the effect on the dynamic response of the flexible foundation provided by the platform, and the determination of thermal stresses at critical locations.
Although this design has been developed for offshore use, the techniques utilized can be applied equally to onshore applications.
Optimization Aspects of an Ejector Type Hypersonic Thrust Nozzle
Authors: Trittler G. , Eckert E. , Göing M. 
Published: March 2015

Hypersonic aircraft projects are highly dependant on efficient propulsion systems. High performance and integration within the airframe play a vital role in the overall concept. Particular attention must be paid to the exhaust system that is submitted to a wide range of operational requirements.
An optimization of the nozzle geometry for high flight Mach numbers will lead to a low performance at the transonic flight regime. The additional use of secondary ejector air flow at transonic speeds is one option to improve the thrust behaviour of the nozzle.
In the presented paper performance data of single expansion ramp ejector type nozzles are predicted using a calculation model based on a method-of-characteristics algorithm. For optimization purposes the effects of various design parameters on axial thrust coefficient and thrust vector angle are discussed. The geometric parameters investigated are the length of the lower nozzle wall and its deflection angle as well as the ejector slot location and its cross-section.
Expert Systems for the Simulation of Gas Turbine Engines
Authors: Torella G. 
Published: March 2015

The paper deals with the possibility to develop effective Expert Systems for the simulation, the monitoring and the diagnostics of engines.
The work concerns with the development of suitable Knowledge Bases and Expert Systems for different activities.
The approach to the problem deals with Expert Systems for engine simulation. These Systems give the operating limits of the engine and the required control laws for reaching assigned values of performance.
Other Expert Systems have been developed for fault simulation. The matrices of influence have proved to be suitable for constructing effective Knowledge Bases.
Finally Expert Systems for engine diagnostics have been set-up.
The paper shows in full detail the methods, the techniques and several applications of the developed codes.
State of the Art of Ultrasonic Liquid Flow Measurement and it’s Impact on Automated Leak Detection in Pipelines
Authors: Smulski Michael L. 
Published: March 2015

The state of the art of ultrasonic liquid flow measurement has improved greatly in the past decade to where this technology exhibits accuracy equivalent to turbine meter systems, while retaining several advantages over turbine meters.
Testing of a four path non-intrusive meter used for leak detection on the Trans–Alaska Pipeline is discussed. Performance is detailed, and future applications for ultrasonic flow measurement technology are reviewed.
Turbocompressor Antisurge Control, New Solution for an Old Problem
Authors: Gaston John R. 
Published: March 2015

The performance of many antisurge control systems is degraded because they do not adequately compensate for variable gas properties (primarily molecular weight). The consequences can range from inefficient operation to serious compressor damage due to surges.
To eliminate deficiencies previously experienced, a new, relatively simple (requires measuring only three process variables) system was developed for a machine which normally compresses a 24.2 molecular weight gas, but is also required to operate on other gas mixtures of approximately 40% lower molecular weight. The new method is explained and the results compared with two other widely used concepts.
Third-Generation-Cephalosporin-Resistant Klebsiella pneumoniae Isolates from Humans and Companion Animals in Switzerland: Spread of a DHA-Producing Sequence Type 11 Clone in a Veterinary Setting
Authors: Wohlwend Nadia , Endimiani Andrea , Francey Thierry , Perreten Vincent 
Published: March 2015

ABSTRACT

Characterization of third-generation-cephalosporin-resistant
Klebsiella pneumoniae
isolates originating mainly from one human hospital (
n
= 22) and one companion animal hospital (
n
= 25) in Bern (Switzerland) revealed the absence of epidemiological links between human and animal isolates. Human infections were not associated with the spread of any specific clone, while the majority of animal infections were due to
K. pneumoniae
sequence type 11 isolates producing plasmidic DHA AmpC. This clonal dissemination within the veterinary hospital emphasizes the need for effective infection control practices.
Profiling of β-Lactam Selectivity for Penicillin-Binding Proteins in Escherichia coli Strain DC2
Authors: Kocaoglu Ozden , Carlson Erin E. 
Published: March 2015

ABSTRACT

Penicillin-binding proteins (PBPs) are integral players in bacterial cell division, and their catalytic activities can be monitored with β-lactam-containing chemical probes. Compounds that target a single PBP could provide important information about the specific role(s) of each enzyme, making identification of such molecules important. We evaluated 22 commercially available β-lactams for inhibition of the PBPs in live
Escherichia coli
strain DC2. Whole cells were titrated with β-lactam antibiotics and subsequently incubated with a fluorescent penicillin derivative, Bocillin-FL (Boc-FL), to label uninhibited PBPs. Protein visualization was accomplished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation and fluorescent scanning. The examined β-lactams exhibited diverse PBP selectivities, with amdinocillin (mecillinam) showing selectivity for PBP2, aztreonam, piperacillin, cefuroxime, cefotaxime, and ceftriaxone for PBP3, and amoxicillin and cephalexin for PBP4. The remaining β-lactams did not block any PBPs in the DC2 strain of
E. coli
or inhibited more than one PBP at all examined concentrations in this Gram-negative organism.
Identification and Characterization of Multidrug-Resistant Salmonella enterica Serotype Albert Isolates in the United States
Authors: Folster Jason P. , Campbell Davina , Grass Julian , Brown Allison C. , Bicknese Amelia , Tolar Beth , Joseph Lavin A. , Plumblee Jodie R. , Walker Carrie , Fedorka-Cray Paula J. , Whichard Jean M. 
Published: March 2015

ABSTRACT

Salmonella enterica
is one of the most common causes of bacterial foodborne illness in the United States. Although most
Salmonella
infections are self-limiting, antimicrobial treatment of invasive salmonellosis is critical. The primary antimicrobial treatment options include fluoroquinolones or extended-spectrum cephalosporins, and resistance to these antimicrobial drugs may complicate treatment. At present,
S. enterica
is composed of more than 2,600 unique serotypes, which vary greatly in geographic prevalence, ecological niche, and the ability to cause human disease, and it is important to understand and mitigate the source of human infection, particularly when antimicrobial resistance is found. In this study, we identified and characterized 19
S. enterica
serotype Albert isolates collected from food animals, retail meat, and humans in the United States during 2005 to 2013. All five isolates from nonhuman sources were obtained from turkeys or ground turkey, and epidemiologic data suggest poultry consumption or live-poultry exposure as the probable source of infection.
S. enterica
serotype Albert also appears to be geographically localized to the midwestern United States. All 19 isolates displayed multidrug resistance, including decreased susceptibility to fluoroquinolones and resistance to extended-spectrum cephalosporins. Turkeys are a likely source of multidrug-resistant
S. enterica
serotype Albert, and circulation of resistance plasmids, as opposed to the expansion of a single resistant strain, is playing a role. More work is needed to understand why these resistance plasmids spread and how their presence and the serotype they reside in contribute to human disease.
Sequence Elements Upstream of the Core Promoter Are Necessary for Full Transcription of the Capsule Gene Operon in Streptococcus pneumoniae Strain D39
Authors: Wen Zhensong , Sertil Odeniel , Cheng Yongxin , Zhang Shanshan , Liu Xue , Wang Wen-Ching , Zhang Jing-Ren 
Published: March 2015

ABSTRACT

Streptococcus pneumoniae
is a major bacterial pathogen in humans. Its polysaccharide capsule is a key virulence factor that promotes bacterial evasion of human phagocytic killing. While
S. pneumoniae
produces at least 94 antigenically different types of capsule, the genes for biosynthesis of almost all capsular types are arranged in the same locus. The transcription of the capsular polysaccharide (
cps
) locus is not well understood. This study determined the transcriptional features of the
cps
locus in the type 2 virulent strain D39. The initial analysis revealed that the
cps
genes are cotranscribed from a major transcription start site at the −25 nucleotide (G) upstream of
cps2A
, the first gene in the locus. Using unmarked chromosomal truncations and a luciferase-based transcriptional reporter, we showed that the full transcription of the
cps
genes not only depends on the core promoter immediately upstream of
cps2A
, but also requires additional elements upstream of the core promoter, particularly a 59-bp sequence immediately upstream of the core promoter. Unmarked deletions of these promoter elements in the D39 genome also led to significant reduction in CPS production and virulence in mice. Lastly, common
cps
gene (
cps2ABCD
) mutants did not show significant abnormality in
cps
transcription, although they produced significantly less CPS, indicating that the CpsABCD proteins are involved in the encapsulation of
S. pneumoniae
in a posttranscriptional manner. This study has yielded important information on the transcriptional characteristics of the
cps
locus in
S. pneumoniae
.
ThefsrQuorum-Sensing System and Cognate Gelatinase Orchestrate the Expression and Processing of Proprotein EF_1097 into the Mature Antimicrobial Peptide Enterocin O16
Authors: Dundar Halil , Brede Dag A. , La Rosa Sabina Leanti , El-Gendy Ahmed Osama , Diep Dzung B. , Nes Ingolf F. 
Published: March 2015

ABSTRACTA novel antimicrobial peptide designated enterocin O16 was purified fromEnterococcus faecalis. Mass spectrometry showed a monoisotopic mass of 7,231 Da, and N-terminal Edman degradation identified a 29-amino-acid sequence corresponding to residues 90 to 119 of the EF_1097 protein. Bioinformatic analysis showed that enterocin O16 is composed of the 68 most C-terminal residues of the EF_1097 protein. Introduction of an in-frame isogenic deletion in theef1097gene abolished the production of enterocin O16. Enterocin O16 has a narrow inhibitory spectrum, as it inhibits mostly lactobacilli. Apparently,E. faecalisis intrinsically resistant to the antimicrobial peptide, as no immunity connected to the production of enterocin O16 could be identified.ef1097has previously been identified as one of three loci regulated by thefsrquorum-sensing system. The introduction of a nonsense mutation intofsrBconsistently impaired enterocin O16 production, but externally added gelatinase biosynthesis-activating pheromone restored the antimicrobial activity. Functional genetic analysis showed that the EF_1097 proprotein is processed extracellularly into enterocin O16 by the metalloprotease GelE. Thus, it is evident that thefsrquorum-sensing system constitutes the regulatory unit that controls the expression of the EF_1097 precursor protein and the protease GelE and that the latter is required for the formation of enterocin O16. On the basis of these results, this study identified antibacterial antagonism as a novel aspect related to the function offsrand provides a rationale for whyef1097is part of thefsrregulon.IMPORTANCEThefsrquorum-sensing system modulates important physiological functions inE. faecalisvia the activity of GelE. The present study presents a new facet offsrsignaling. The system controls the expression of three primary target operons (fsrABCD,gelE-sprE, andef1097-ef1097b). We demonstrate that the concerted expression of these operons constitutes the elements necessary for the production of a bacteriocin-type peptide and that antimicrobial antagonism is an intrinsic function offsr. The bacteriocin enterocin O16 consists of the 68 most C-terminal residues of the EF_1097 secreted proprotein. The GelE protease processes the EF_1097 proprotein into enterocin O16. In this manner,fsrsignaling enablesE. faecalispopulations to express antimicrobial activity in a cell density-dependent manner.
Evolution of Molybdenum Nitrogenase during the Transition from Anaerobic to Aerobic Metabolism
Authors: Boyd Eric S. , Costas Amaya M. Garcia , Hamilton Trinity L. , Mus Florence , Peters John W. 
Published: March 2015

ABSTRACTMolybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Phylogenetic evidence indicates that oxygen (O2)-sensitive Nif emerged in an anaerobic archaeon and later diversified into an aerobic bacterium. Aerobic bacteria that fix N2have adapted a number of strategies to protect Nif from inactivation by O2, including spatial and temporal segregation of Nif from O2and respiratory consumption of O2. Here we report the complement of Nif-encoding genes in 189 diazotrophic genomes. We show that the evolution of Nif during the transition from anaerobic to aerobic metabolism was accompanied by both gene recruitment and loss, resulting in a substantial increase in the number ofnifgenes. While the observed increase in the number ofnifgenes and their phylogenetic distribution are strongly correlated with adaptation to utilize O2in metabolism, the increase is not correlated with any of the known O2protection mechanisms. Rather, gene recruitment appears to have been in response to selective pressure to optimize Nif synthesis to meet fixed N demands associated with aerobic productivity and to more efficiently regulate Nif under oxic conditions that favor protein turnover. Consistent with this hypothesis, the transition of Nif from anoxic to oxic environments is associated with a shift from posttranslational regulation in anaerobes to transcriptional regulation in obligate aerobes and facultative anaerobes. Given that fixed nitrogen typically limits ecosystem productivity, our observations further underscore the dynamic interplay between the evolution of Earth's oxygen, nitrogen, and carbon biogeochemical cycles.IMPORTANCEMolybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Nif emerged in an anaerobe and later diversified into aerobes. Here we show that the transition of Nif from anaerobic to aerobic metabolism was accompanied by both gene recruitment and gene loss, resulting in a substantial increase in the number ofnifgenes. While the observed increase in the number ofnifgenes is strongly correlated with adaptation to utilize O2in metabolism, the increase is not correlated with any of the known O2protective mechanisms. Rather, gene recruitment was likely a response to more efficiently regulate Nif under oxic conditions that favor protein turnover.
Acupuncture for Joint Symptoms Related to Aromatase Inhibitor Therapy in Postmenopausal Women with Early-Stage Breast Cancer: A Narrative Review
Authors: Halsey Elizabeth J , Xing Mei , Stockley Rachel C 
Published: March 2015

Background Aromatase inhibitor-induced musculoskeletal syndrome (AIMSS) leads to discontinuation of aromatase inhibitor therapy in a significant proportion of patients with breast cancer. Acupuncture is popular among cancer patients and has previously been shown to improve symptoms in a range of musculoskeletal complaints. Aim To determine the effectiveness and safety of acupuncture for the management of AIMSS in postmenopausal women with early-stage breast cancer. Methods A literature search was carried out for randomised controlled trials (RCTs) on acupuncture for AIMSS in postmenopausal women with early-stage breast cancer. Characteristics of trials and outcomes were extracted from the retrieved articles, which were also assessed for risk of bias and quality of reporting. Results Four RCTs were retrieved of sample size 32–67 (totalling 190 participants). Compliance with treatment was high and rates of adverse events were low. Of the three two-arm RCTs, two found no difference between acupuncture and sham acupuncture and one found that acupuncture was statistically superior to sham acupuncture. The fourth RCT, which incorporated three arms, found acupuncture and sham acupuncture to be statistically superior to usual care but there was no difference between true and sham acupuncture. Three trials that used non-penetrating sham as the control found no effect of acupuncture over sham, but the one trial that used superficial needle insertion found acupuncture to be superior. Conclusions Acupuncture is safe and results in improvement in AIMSS symptoms, but similar benefits are also elicited by non-penetrating sham acupuncture. Future research should seek to establish the durability of improvements.
Aetiology of arthritis in hospitalised children: an observational study
Authors: Aupiais Camille , Ilharreborde Brice , Doit Catherine , Blachier Audrey , Desmarest Marie , Job-Deslandre Chantal , Mazda Keyvan , Faye Albert , Bonacorsi Stéphane , Alberti Corinne , Lorrot Mathie 
Published: March 2015

Background and objectiveArthritis in children has many causes and includes septic and viral arthritis, reactive arthritis and juvenile idiopathic arthritis (JIA). We aimed to describe the different types of arthritis among children hospitalised for a first episode of arthritis.DesignRetrospective, descriptive case series study.SettingA French tertiary care centre.PatientsChildren under 16 years of age hospitalised for an arthritis episode between 1 January 2008 and 31 December 2009.Main outcome measuresDemographic and clinical features were compared with χ2or Fisher's exact tests and non-parametric tests.Results173 children were hospitalised for a first episode of arthritis during the study period, with a male/female ratio of 1.14. The most frequent cause of hospitalisation was septic arthritis (43.4% of cases, 69.3% of which were due toKingella kingaeand 10.7% toStaphylococcus aureus). JIA was responsible for 8.1% of cases and arthritis without any definitive diagnosis for 40.4%. Median age at diagnosis was 2.7 years (IQR 0.3–14.6) and was lower in the septic arthritis group (1.5 years; 1.1–3.4) than in the JIA group (4.7 years; 2.5–10.9) (p<0.01). Septic arthritis involved a single joint in 97.3% of cases, while JIA involved four joints in 14.3% of cases and two to four joints in 28.6% of cases (p<0.01).ConclusionsSeptic arthritis was the most frequent cause of arthritis in hospitalised children. Despite the increasing application of microbiological molecular methods to synovial fluid analysis, further measures are required to improve the diagnosis of arthritis of unknown cause.
Outcome of patients admitted with acute coronary syndrome on palliative treatment: insights from the nationwide AMIS Plus Registry 1997–2014
Authors: Erne Paul , Radovanovic Dragana , Seifert Burkhardt , Bertel Osmund , Urban Philip 
Published: March 2015

ObjectiveCompliance with guidelines is increasingly used to benchmark the quality of hospital care, however, very little is known on patients admitted with acute coronary syndromes (ACS) and treated palliatively. This study aimed to evaluate the baseline characteristics and outcomes of these patients.DesignProspective cohort study.SettingEighty-two Swiss hospitals enrolled patients from 1997 to 2014.ParticipantsAll patients with ACS enrolled in the AMIS Plus registry (n=45 091) were analysed according to three treatment groups: palliative treatment, defined as use of aspirin and analgesics only and no reperfusion; conservative treatment, defined as any treatment including antithrombotics or anticoagulants, heparins, P2Y12inhibitors, GPIIb/IIIa but no pharmacological or mechanical reperfusion; and reperfusion treatment (thrombolysis and/or percutaneous coronary intervention during initial hospitalisation). The primary outcome measure was in-hospital mortality and the secondary measure was 1-year mortality.ResultsOf the patients, 1485 (3.3%) were palliatively treated, 11 119 (24.7%) were conservatively treated and 32 487 (72.0%) underwent reperfusion therapy. In 1997, 6% of all patients were treated palliatively and this continuously decreased to 2% in 2013. Baseline characteristics of palliative patients differed in comparison with conservatively treated and reperfusion patients in age, gender and comorbidities (all p<0.001). These patients had more in-hospital complications such as postadmission onset of cardiogenic shock (15.6% vs 5.2%; p<0.001), stroke (1.8% vs 0.8%; p=0.001) and a higher in-hospital mortality (25.8% vs 5.6%; p<0.001).The subgroup of patients followed 1 year after discharge (n=8316) had a higher rate of reinfarction (9.2% vs 3.4%; p=0.003) and mortality (14.0% vs 3.5%; p<0.001).ConclusionsPatients with ACS treated palliatively were older, sicker, with more heart failure at admission and very high in-hospital mortality. While refraining from more active therapy may often constitute the most humane and appropriate approach, we think it is important to also evaluate these patients and include them in registries and outcome evaluations.Clinical trial numberClinicalTrials.gov Identifier: NCT01 305 785.