bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and Evaluation of Silicon Nitride Components for Ceramic Gas Turbine
Authors: Hara Yasushi , Matsubara Katsura , Mizuno Ken-ichi , Shimamori Toru , Yoshida Hiro 
Published: December 2014

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles.
In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1350 °C in accordance with the project goals, we developed two silicon nitride materials with further improved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles.
On applying these silicon nitride ceramics to CGT engine, we evaluated various properties of silicon nitride materials considering the environment in CGT engine. Particle impact testing is one of those evaluations. Materials used in CGT engine are exposed in high speed gas flow, and impact damage of these materials is considered to be a concern. We tested ST-1 in the particle impact test. In this test, we observed fracture modes, and estimated the critical impact velocity.
This paper summarizes the development of silicon nitride components, and the result of evaluations of these silicon nitride materials.
Ceramic Stationary Gas Turbine Development Program — Design and Test of a Ceramic Turbine Blade
Authors: Jimenez Oscar , McClain John , Edwards Bryan , Parthasarathy Vijay , Bagheri Hamid , Bolander Gary 
Published: December 2014

The goal of the Ceramic Stationary Gas Turbine (CSGT) Development Program, under the sponsorship of the United States Department of Energy (DOE), Office of Industrial Technologies (OIT), is to improve the performance (fuel efficiency, output power, and exhaust emissions) of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. This program, which is headed by Solar Turbines Incorporated and supported by various suppliers, and national research institutes, includes detailed engine and component design, procurement, and field testing.
A major challenge in the successful introduction of ceramic parts into a gas turbine is the design of the interface between the ceramic parts and metallic hardware. A turbine blade, which incorporated a dovetail root, was designed with such considerations. A relatively thin compliant layer between the ceramic-metallic loading surface was considered for equalizing pressure face load distributions.
Five monolithic siliocn nitride ceramic materials were considered: AS800 and GN10, AlliedSignal Ceramic Components; NT164, Norton Advanced Ceramics; SN281 and SN253, Kyocera Industrial Ceramics Corporation. The probability of survival using NASA/CARES for 30,000 hours of engine operation was calculated for each material. The blade frequencies, stresses, and temperatures were predicted. The influence of the dovetail angle was also analyzed to determine the most optimum configuration. Prior to engine installation all blades underwent extensive nondestructive evaluation and spin proof testing. This paper will review the design, life prediction, and testing of the first stage ceramic turbine blade for the Solar Turbines Centaur 5OS engine.
The Effect of Turbulence on the Heat Transfer in Closed Gas-Filled Rotating Annuli for Different Rayleigh Numbers
Authors: Bohn Dieter , Gier Jochen 
Published: December 2014

Higher turbine inlet temperatures are a common method of increasing the thermal efficiency of modern gas turbines. This development not only generates the need for more efficient turbine blade cooling but also demands a more profound knowledge of the mechanically and thermally stressed parts of the rotor. In order to determine thermal stresses from the temperature distribution in the rotor of a gas turbine, one has to encounter the convective heat transfer in rotor cavities. In the special case of a completely closed gas-filled rotating annulus the convective flow is governed by strong natural convection.
As shown in a previous paper by the authors, and for example by Owen, the presence of turbulence and its inclusion in the modeling of the flow has been found to cause significant differences in the flow development in rotating annuli. This influence in the special case of a closed rotating annulus has been recently investigated by the authors for a moderately high Rayleigh-Number. Based on this work an investigation was undertaken focusing on the development of turbulence and turbulence related changes in the flow structure for increasing Rayleigh-Numbers.
The flow is investigated numerically using a three-dimensional Navier-Stokes solver, based on a pressure correction scheme. To account for the turbulence, a low-Reynolds-number k-ε-model is employed. This model is complemented by an additional term for turbulence production due to buoyancy. The results are compared with experiments performed at the Institute of Steam and Gas Turbines. The computations demonstrate the considerable influence on the overall heat transfer as well as on the local heat transfer distribution.
The CNAO dose delivery system for modulated scanning ion beam radiotherapy
Authors: Giordanengo S. , Garella M. A. , Marchetto F. , Bourhaleb F. , Ciocca M. , Mirandola A. , Monaco V. , Hosseini M. A. , Peroni C. , Sacchi R. , Cirio R. , Donetti M. 
Published: December 2014

Purpose:This paper describes the system for the dose delivery currently used at the Centro Nazionale di Adroterapia Oncologica (CNAO) for ion beam modulated scanning radiotherapy.Methods:CNAO Foundation, Istituto Nazionale di Fisica Nucleare and University of Torino have designed, built, and commissioned a dose delivery system (DDS) to monitor and guide ion beams accelerated by a dedicated synchrotron and to distribute the dose with a full 3D scanning technique. Protons and carbon ions are provided for a wide range of energies in order to cover a sizable span of treatment depths. The target volume, segmented in several layers orthogonally to the beam direction, is irradiated by thousands of pencil beams which must be steered and held to the prescribed positions until the prescribed number of particles has been delivered. For the CNAO beam lines, these operations are performed by the DDS. The main components of this system are two independent beam monitoring detectors, called BOX1 and BOX2, interfaced with two control systems performing the tasks of real‐time fast and slow control, and connected to the scanning magnets and the beam chopper. As a reaction to any condition leading to a potential hazard, a DDS interlock signal is sent to the patient interlock system which immediately stops the irradiation. The essential tasks and operations performed by the DDS are described following the data flow from the treatment planning system through the end of the treatment delivery.Results:The ability of the DDS to guarantee a safe and accurate treatment was validated during the commissioning phase by means of checks of the charge collection efficiency, gain uniformity of the chambers, and 2D dose distribution homogeneity and stability. A high level of reliability and robustness has been proven by three years of system activity needing rarely more than regular maintenance and working with 100% uptime. Four identical and independent DDS devices have been tested showing comparable performances and are presently in use on the CNAO beam lines for clinical activity.Conclusions:The dose delivery system described in this paper is one among the few worldwide existing systems to operate ion beam for modulated scanning radiotherapy. At the time of writing, it has been used to treat more than 350 patients and it has proven to guide and control the therapeutic pencil beams reaching performances well above clinical requirements. In particular, in terms of dose accuracy and stability, daily quality assurance measurements have shown dose deviations always lower than the acceptance threshold of 5% and 2.5%, respectively.
In Vitro
Susceptibility of Characterized β-Lactamase-Producing Strains Tested with Avibactam Combinations
Authors: Li Henry , Estabrook Mark , Jacoby George A. , Nichols Wright W. , Testa Raymond T. , Bush Karen 
Published: December 2014

ABSTRACT

Avibactam, a broad-spectrum β-lactamase inhibitor, was tested with ceftazidime, ceftaroline, or aztreonam against 57 well-characterized Gram-negative strains producing β-lactamases from all molecular classes. Most strains were nonsusceptible to the β-lactams alone. Against AmpC-, extended-spectrum β-lactamase (ESBL)-, and KPC-producing
Enterobacteriaceae
or
Pseudomonas aeruginosa
, avibactam lowered ceftazidime, ceftaroline, or aztreonam MICs up to 2,048-fold, to ≤4 μg/ml. Aztreonam-avibactam MICs against a VIM-1 metallo-β-lactamase-producing
Enterobacter cloacae
and a VIM-1/KPC-3-producing
Escherichia coli
isolate were 0.12 and 8 μg/ml, respectively.
Multicenter, Randomized Clinical Trial To Compare the Safety and Efficacy of LFF571 and Vancomycin for Clostridium difficile Infections
Authors: Mullane Kathleen , Lee Christine , Bressler Adam , Buitrago Martha , Weiss Karl , Dabovic Kristina , Praestgaard Jens , Leeds Jennifer A. , Blais Johanne , Pertel Peter 
Published: December 2014

ABSTRACT

Clostridium difficile
infection causes serious diarrheal disease. Although several drugs are available for treatment, including vancomycin, recurrences remain a problem. LFF571 is a semisynthetic thiopeptide with potency against
C. difficile
in vitro
. In this phase 2 exploratory study, we compared the safety and efficacy (based on a noninferiority analysis) of LFF571 to those of vancomycin used in adults with primary episodes or first recurrences of moderate
C. difficile
infection. Patients were randomized to receive 200 mg of LFF571 or 125 mg of vancomycin four times daily for 10 days. The primary endpoint was the proportion of clinical cures at the end of therapy in the per-protocol population. Secondary endpoints included clinical cures at the end of therapy in the modified intent-to-treat (mITT) population, the time to diarrhea resolution, and the recurrence rate. Seventy-two patients were randomized, with 46 assigned to receive LFF571. Based on the protocol-specified definition, the rate of clinical cure for LFF571 (90.6%) was noninferior to that of vancomycin (78.3%). The 30-day sustained cure rates for LFF571 and vancomycin were 56.7% and 65.0%, respectively, in the per-protocol population and 58.7% and 60.0%, respectively, in the modified intent-to-treat population. Using toxin-confirmed cases only, the recurrence rates were lower for LFF571 (19% versus 25% for vancomycin in the per-protocol population). LFF571 was generally safe and well tolerated. The incidence of adverse events (AEs) was higher for LFF571 (76.1% versus 69.2% for vancomycin), although more AEs in the vancomycin group were suspected to be related to the study drug (38.5% versus 32.6% for LFF571). One patient receiving LFF571 discontinued the study due to an AE. (This study has been registered at ClinicalTrials.gov under registration no. NCT01232595.)
Fidaxomicin Therapy in Critically Ill Patients with Clostridium difficile Infection
Authors: Penziner Samuel , Dubrovskaya Yanina , Press Robert , Safdar Amar 
Published: December 2014

ABSTRACT

Fidaxomicin use to treat proven
Clostridium difficile
infection (CDI) was compared between 20 patients receiving care in critical care units (CCUs) and 30 patients treated on general medical floors. At baseline, the CCU patients had more initial CDI episodes, more severe and complicated disease, and more concurrent broad-spectrum antibiotic coverage. On multivariate analysis, the response to fidaxomicin therapy among the critically ill patients was comparable to that among patients in the general medical wards.
Antisecretory Factor Peptide AF-16 Inhibits the Secreted Autotransporter Toxin-Stimulated Transcellular and Paracellular Passages of Fluid in Cultured Human Enterocyte-Like Cells
Authors: Nicolas Valérie , Liévin-Le Moal Vanessa 
Published: December 2014

ABSTRACT

Both the endogenous antisecretory factor (AF) protein and peptide AF-16, which has a sequence that matches that of the active N-terminal region of AF, inhibit the increase in the epithelial transport of fluid and electrolytes induced by bacterial toxins in animal and
ex vivo
models. We conducted a study to investigate the inhibitory effect of peptide AF-16 against the increase of transcellular passage and paracellular permeability promoted by the
s
ecreted
a
utotransporter
t
oxin (Sat) in a cultured cellular model of the human intestinal epithelial barrier. Peptide AF-16 produced a concentration-dependent inhibition of the Sat-induced increase in the formation of fluid domes, in the mucosal-to-serosal passage of
d
-[1-
14
C]mannitol, and in the rearrangements in the distribution and protein expression of the tight junction (TJ)-associated proteins ZO-1 and occludin in cultured human enterocyte-like Caco-2/TC7 cell monolayers. In addition, we show that peptide AF-16 also inhibits the cholera toxin-induced increase of transcellular passage and the
Clostridium difficile
toxin-induced effects on paracellular permeability and TJ protein organization in Caco-2/TC7 cell monolayers. Treatment of cell monolayers by the lipid raft disorganizer methyl-β-cyclodextrin abolished the inhibitory activity of peptide AF-16 at the transcellular passage level and did not modify the effect of the peptide at the paracellular level.
Enterohemorrhagic Escherichia coli Colonization of Human Colonic Epithelium
In Vitro
and
Ex Vivo
Authors: Lewis Steven B. , Cook Vivienne , Tighe Richard , Schüller Stephanie 
Published: December 2014

ABSTRACT

Enterohemorrhagic
Escherichia coli
(EHEC) is an important foodborne pathogen causing gastroenteritis and more severe complications, such as hemorrhagic colitis and hemolytic uremic syndrome. Pathology is most pronounced in the colon, but to date there is no direct clinical evidence showing EHEC binding to the colonic epithelium in patients. In this study, we investigated EHEC adherence to the human colon by using
in vitro
organ culture (IVOC) of colonic biopsy samples and polarized T84 colon carcinoma cells. We show for the first time that EHEC colonizes human colonic biopsy samples by forming typical attaching and effacing (A/E) lesions which are dependent on EHEC type III secretion (T3S) and binding of the outer membrane protein intimin to the translocated intimin receptor (Tir). A/E lesion formation was dependent on oxygen levels and suppressed under oxygen-rich culture conditions routinely used for IVOC. In contrast, EHEC adherence to polarized T84 cells occurred independently of T3S and intimin and did not involve Tir translocation into the host cell membrane. Colonization of neither biopsy samples nor T84 cells was significantly affected by expression of Shiga toxins. Our study suggests that EHEC colonizes and forms stable A/E lesions on the human colon, which are likely to contribute to intestinal pathology during infection. Furthermore, care needs to be taken when using cell culture models, as they might not reflect the
in vivo
situation.
Activation of the σ
E
-Dependent Stress Pathway by Conjugative TraR May Anticipate Conjugational Stress
Authors: Grace Elicia D. , Gopalkrishnan Saumya , Girard Mary E. , Blankschien Matthew D. , Ross Wilma , Gourse Richard L. , Herman Christophe 
Published: December 2014

ABSTRACT

Horizontal gene transfer by conjugation plays a major role in bacterial evolution, allowing the acquisition of new traits, such as virulence and resistance to antibacterial agents. With the increased antibiotic resistance in bacterial pathogens, a better understanding of how bacteria modulate conjugation under changing environments and the genetic factors involved is needed. Despite the evolutionary advantages conjugation may confer, the process can be quite stressful for the donor cell. Here, we characterize the ability of TraR, encoded on the episomal F′ plasmid, to upregulate the σ
E
extracytoplasmic stress pathway in
Escherichia coli
. TraR, a DksA homolog, modulates transcription initiation through the secondary channel of RNA polymerase. We show here that TraR activates transcription directly; however, unlike DksA, it does so without using ppGpp as a cofactor. TraR expression can stimulate the σ
E
extracytoplasmic stress response independently of the DegS/RseA signal transduction cascade. In the absence of TraR, bacteria carrying conjugative plasmids become more susceptible to external stress. We propose that TraR increases the concentrations of periplasmic chaperones and proteases by directly activating the transcription of σ
E
-dependent promoters; this increased protein folding capacity may prepare the bacterium to endure the periplasmic stress of sex pilus biosynthesis during mating.
Transcriptional Regulation of the Vanillate Utilization Genes (
vanABK
Operon) of Corynebacterium glutamicum by VanR, a PadR-Like Repressor
Authors: Morabbi Heravi Kambiz , Lange Julian , Watzlawick Hildegard , Kalinowski Jörn , Altenbuchner Josef 
Published: December 2014

ABSTRACT

Corynebacterium glutamicum
is able to utilize vanillate, the product of lignin degradation, as the sole carbon source. The vanillate utilization components are encoded by the
vanABK
operon. The
vanA
and
vanB
genes encode the subunits of vanillate
O
-demethylase, converting vanillate to protocatechuate, while VanK is the specific vanillate transporter. The
vanABK
operon is regulated by a PadR-type repressor, VanR. Heterologous gene expression and variations of the
vanR
open reading frame revealed that the functional VanR contains 192 residues (21 kDa) and forms a dimer, as analyzed by size exclusion chromatography.
In vivo
, ferulate, vanillin, and vanillate induced P

vanABK

in
C. glutamicum
, while only vanillate induced the activity of P

vanABK

in
Escherichia coli
lacking the ferulate catabolic system. Differential scanning fluorimetry verified that vanillate is the only effector of VanR. Interaction between the P

vanABK

DNA fragment and the VanR protein had an equilibrium dissociation constant (

K
D

) of 15.1 ± 1.7 nM. The VanR-DNA complex had a dissociation rate constant (

K
d

) of (267 ± 23) × 10
−6
s
−1
, with a half-life of 43.5 ± 3.6 min. DNase I footprinting localized the VanR binding site at P

vanABK

, extending from +9 to +45 on the coding strand. Deletion of the nucleotides +18 to +27 inside the VanR binding site rendered P

vanABK

constitutive. Fusion of the T7 promoter and the wild-type VanR operator, as well as its shortened versions, indicated that the inverted repeat AACTAACTAA(N
4
)TTAGGTATTT is the specific VanR binding site. It is proposed that the VanR-DNA complex contains two VanR dimers at the VanR operator.
Long-term effect of computer-assisted decision support for antibiotic treatment in critically ill patients: a prospective ‘before/after’ cohort study
Authors: Nachtigall I , Tafelski S , Deja M , Halle E , Grebe M C , Tamarkin A , Rothbart A , Uhrig A , Meyer E , Musial-Bright L , Wernecke K D , Spies C 
Published: December 2014

ObjectivesAntibiotic resistance has risen dramatically over the past years. For individual patients, adequate initial antibiotic therapy is essential for clinical outcome. Computer-assisted decision support systems (CDSSs) are advocated to support implementation of rational anti-infective treatment strategies based on guidelines. The aim of this study was to evaluate long-term effects after implementation of a CDSS.DesignThis prospective ‘before/after’ cohort study was conducted over four observation periods within 5 years. One preinterventional period (pre) was compared with three postinterventional periods: directly after intensive implementation efforts (post1), 2 years (post2) and 3 years (post3) after implementation.SettingFive anaesthesiological-managed intensive care units (ICU) (one cardiosurgical, one neurosurgical, two interdisciplinary and one intermediate care) at a university hospital.ParticipantsAdult patients with an ICU stay of >48 h were included in the analysis. 1316 patients were included in the analysis for a total of 12 965 ICU days.InterventionImplementation of a CDSS.Outcome measuresThe primary end point was percentage of days with guideline adherence during ICU treatment. Secondary end points were antibiotic-free days and all-cause mortality compared for patients with low versus high guideline adherence.Main resultsAdherence to guidelines increased from 61% prior to implementation to 92% in post1, decreased in post2 to 76% and remained significantly higher compared with baseline in post3, with 71% (p=0.178). Additionally, antibiotic-free days increased over study periods. At all time periods, mortality for patients with low guideline adherence was higher with 12.3% versus 8% (p=0.014) and an adjusted OR of 1.56 (95% CI 1.05 to 2.31).ConclusionsImplementation of computerised regional adapted guidelines for antibiotic therapy is paralleled with improved adherence. Even without further measures, adherence stayed high for a longer period and was paralleled by reduced antibiotic exposure. Improved guideline adherence was associated with reduced ICU mortality.Trial registration numberISRCTN54598675.
Perceived barriers to smoking cessation in selected vulnerable groups: a systematic review of the qualitative and quantitative literature
Authors: Twyman Laura , Bonevski Billie , Paul Christine , Bryant Jamie 
Published: December 2014

ObjectivesTo identify barriers that are common and unique to six selected vulnerable groups: low socioeconomic status; Indigenous; mental illness and substance abuse; homeless; prisoners; and at-risk youth.DesignA systematic review was carried out to identify the perceived barriers to smoking cessation within six vulnerable groups.Data sourcesMEDLINE, EMBASE, CINAHL and PsycInfo were searched using keywords and MeSH terms from each database's inception published prior to March 2014.Study selectionStudies that provided either qualitative or quantitative (ie, longitudinal, cross-sectional or cohort surveys) descriptions of self-reported perceived barriers to quitting smoking in one of the six aforementioned vulnerable groups were included.Data extractionTwo authors independently assessed studies for inclusion and extracted data.Results65 eligible papers were identified: 24 with low socioeconomic groups, 16 with Indigenous groups, 18 involving people with a mental illness, 3 with homeless groups, 2 involving prisoners and 1 involving at-risk youth. One study identified was carried out with participants who were homeless and addicted to alcohol and/or other drugs. Barriers common to all vulnerable groups included: smoking for stress management, lack of support from health and other service providers, and the high prevalence and acceptability of smoking in vulnerable communities. Unique barriers were identified for people with a mental illness (eg, maintenance of mental health), Indigenous groups (eg, cultural and historical norms), prisoners (eg, living conditions), people who are homeless (eg, competing priorities) and at-risk youth (eg, high accessibility of tobacco).ConclusionsVulnerable groups experience common barriers to smoking cessation, in addition to barriers that are unique to specific vulnerable groups. Individual-level, community-level and social network-level interventions are priority areas for future smoking cessation interventions within vulnerable groups.Trial registration number:A protocol for this review has been registered with PROSPERO International Prospective Register of Systematic Reviews (Identifier: CRD42013005761).