bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study on the Effect of Pressure Balance Between the Second and Third Land of a Piston on Engine Oil Consumption
Authors: Ohno Yohei , Kikuhara Koji , Ito Akemi , Inui Masatsugu , Akamatsu Hirotaka 
Published: December 2014

Engine oil consumption causes particulate matter, poisoning of catalysts, abnormal combustion like pre-ignition in a gasoline engine, and an increase in customer’s running cost. Oil consumption, therefore, must be reduced.
It is well known that pressure at a piston second land sometimes becomes larger than the cylinder pressure in the latter half of the expansion stroke. Larger pressure at the second land causes an increase in engine oil consumption. For reducing the second land pressure, increasing volume of a piston second land is one of design schemes. Pressure at a piston second land is calculated in piston design stage. In the calculation, pressure at a piston third land is assumed as same as pressure at the crankcase.
This study aimed the effect of volume of the third land of a piston on engine oil consumption. The third and the second lands pressure were measured using an optical fiber type pressure sensor. It was found that the third land pressure showed a quite different trend from the crankcase pressure. It was also found that the pressure balance between the second land and the third land affected engine oil consumption. It was suggested that the third land pressure should be considered in the calculation for lands pressure of a piston and further investigation on third land design for reducing engine oil consumption may be required.
Investigation on Spray and Soot Lift-Off Length of an ABE-Diesel Blend in a Constant Volume Chamber With Diesel Engine Conditions
Authors: Wu Han , Nithyanandan Karthik , Li Boqi , Lee Timothy H. , Lee Chia-fon F. , Zhang Chunhua 
Published: December 2014

Acetone-Butanol-Ethanol (ABE), an intermediate product in the ABE fermentation process for producing bio-butanol, is considered as a promising alternative fuel because it not only preserves the advantages of oxygenated fuel, which typically emit less pollutants compared to conventional diesel, but also lowers the cost of fuel recovery for each individual component during the fermentation. In this work, 20% ABE with component ratio of 3:6:1 and 80% ultra-sulfur diesel by volume, referred as ABE20, and pure diesel, referred as D100, were injected and combusted in a constant volume chamber with the ability to mimic high temperature and high pressure conditions of real diesel cylinder near the top dead center. By adjusting intake partial pressure and injection timing, the ambient oxygen concentration and temperature for fuel injection can be controlled. Ambient temperatures were set at 1100K, 900K and 700K to cover conventional temperature combustion and low temperature combustion, while the ambient oxygen concentrations were set at 21%, 16% and 11% to cover different EGR ratios separately. Spray and natural flame images were captured by a high speed camera coupled with a copper vapor laser as a light source.
The results show that spray liquid penetration and soot lift-off length are shorter and much longer for ABE20 than those for D100 separately under all tested conditions, which form a much bigger gap from spray tip to the combustion area for ABE20. A big gap reduces the local equivalence ratio at the combustion area and then suppresses the soot formation due to the gap is the most effective area for air-fuel mixing processes. Indeed, the natural flame luminosity which represents the soot emission level of ABE20 is significantly lower than that of D100 at all tested conditions. At the same time, ABE20 performed a similar combustion phasing with D100 under high ambient temperature, but experienced an aggressive retardation under low ambient temperatures especially with low ambient oxygen concentrations. In addition, ABE20 did not show a stronger concentrated premixed combustion since its heat release rate peak is lower than that of D100, which was also confirmed by its longer combustion duration. Therefore, ABE20 expresses a high potential to reduce soot emissions but it also has to face combustion deterioration at low temperature combustion conditions.
Piston Ring and Groove Side Wear Analysis for Diesel Engines
Authors: Poort Mulyanto , Cheng Chao , Richardson Dan , Schock Harold 
Published: December 2014

Piston ring wear is a major factor determining a diesel engine’s life. A ring is subjected to wear between its front face and the cylinder wall as well as at the interfaces between the ring and groove top and bottom flanks. In many modern engines, ring and groove wear are becoming more of a limiting factor for ring durability than face wear. The focus of this paper is on ring to groove side wear only.
In this paper two fundamental mechanisms for ring/groove side wear are identified: (1) wear due to piston secondary motion and (2) wear due to ring twist. The time in the cycle where each of these mechanisms results in maximum wear is shown.
Then the effect of ring static twist and the resulting effect on the pressure distribution around the ring are studied. The pressure distribution affects the force acting on the ring that causes the ring/groove side wear. It is also shown that the pressure distribution and the resultant wear can be influenced by the land diameter below the piston ring.
Progressive wear is also studied, showing a good correlation between predicted wear and measured wear on both ring sides and groove sides. It is noted that as the corner of the ring/groove wears, the ultimate wear of the ring side can accelerate by a phenomenon named pressure infiltration. Pressure infiltration occurs because the bottom side of the ring groove wears exposing more of bottom side of the ring to lower pressure force. This ultimately causes a higher difference between the high pressure above the ring and the low pressure below the ring. As a result, the net force acting on the ring increases and wear increases.
In addition to the study of the first ring, the second ring wear was studied. A comparison was made between the top ring and second ring groove side wear (RGSW) predictions. Also the effect of the second ring static twist on both top and second ring/groove side wear is described in detail.
Limited-Sampling Strategies for Anidulafungin in Critically Ill Patients
Authors: van Wanrooy Marjolijn J. P. , Proost Johannes H. , Rodgers Michael G. G. , Zijlstra Jan G. , Uges Donald R. A. , Kosterink Jos G. W. , van der Werf Tjip S. , Alffenaar Jan-Willem C. 
Published: December 2014

ABSTRACT

Efficacy of anidulafungin is driven by the area under the concentration-time curve (AUC)/MIC ratio. Determination of the anidulafungin AUC along with MIC values can therefore be useful. Since obtaining a full concentration-time curve to determine an AUC is not always feasible or appropriate, limited-sampling strategies may be useful in adequately estimating exposure. The objective of this study was to develop a model to predict the individual anidulafungin exposure in critically ill patients using limited-sampling strategies. Pharmacokinetic data were derived from 20 critically ill patients with invasive candidiasis treated with anidulafungin. These data were used to develop a two-compartment model in MW\Pharm using an iterative 2-stage Bayesian procedure. Limited-sampling strategies were subsequently investigated using two methods, a Bayesian analysis and a linear regression analysis. The best possible strategies for these two methods were evaluated by a Bland-Altman analysis for correlation of the predicted and observed AUC from 0 to 24 h (AUC
0–24
) values. Anidulafungin exposure can be adequately estimated with the concentration from a single sample drawn 12 h after the start of the infusion either by linear regression (
R
2
= 0.99; bias, 0.05%; root mean square error [RMSE], 3%) or using a population pharmacokinetic model (
R
2
= 0.89; bias, −0.1%; RMSE, 9%) in critically ill patients and also in less severely ill patients, as reflected by healthy volunteers. Limited sampling can be advantageous for future studies evaluating the pharmacokinetics and pharmacodynamics of anidulafungin and for therapeutic drug monitoring in selected patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01047267.)
Assessment of Time to Clinical Response, a Proxy for Discharge Readiness, among Hospitalized Patients with Community-Acquired Pneumonia Who Received either Ceftaroline Fosamil or Ceftriaxone in Two Phase III FOCUS Trials
Authors: Lodise Thomas P. , Anzueto Antonio R. , Weber David J. , Shorr Andrew F. , Yang Min , Smith Alexander , Zhao Qi , Huang Xingyue , File Thomas M. 
Published: December 2014

ABSTRACT

The primary driver of health care costs for patients with community-acquired pneumonia (CAP) is the hospital length of stay (LOS). Unfortunately, hospital LOS comparisons are difficult to make from phase III CAP trials because of their structured designs and prespecified treatment durations. However, an opportunity still exists to draw inferences about potential LOS differences between treatments through the use of surrogates for hospital discharge. The intent of this study was to quantify the time to a clinical response, a proxy for the time to discharge readiness, among hospitalized CAP patients who received either ceftaroline or ceftriaxone in two phase III CAP FOCUS clinical trials. On the basis of the Infectious Diseases Society of America and American Thoracic Society CAP management guidelines and recent FDA guidance documents for community-acquired bacterial pneumonia, a
post hoc
adjudication algorithm was constructed
a priori
to compare the time to a clinical response, a proxy for the time to discharge readiness, between patients who received ceftaroline or ceftriaxone. Overall, 1,116 patients (ceftaroline,
n
= 562; ceftriaxone,
n
= 554) from the pooled FOCUS trials met the selection criteria for this analysis. Kaplan-Meier analyses showed that ceftaroline was associated with a shorter time, measured in days, to meeting the clinical response criteria (
P
= 0.03). Of the patients on ceftaroline, 61.0, 76.1, and 83.6% achieved a clinical response by days 3, 4, and 5, compared to 54.3, 69.8, and 79.3% of the ceftriaxone-treated patients. In the Cox regression, ceftaroline was associated with a shorter time to a clinical response (HR, 1.16,
P
= 0.02). The methodology employed here provides a framework to draw comparative effectiveness inferences from phase III CAP efficacy trials. (The FOCUS trials whose data were analyzed in this study have been registered at
ClinicalTrials.gov
under registration no. NCT00621504 and NCT00509106.)
Mechanisms of Action of Substituted β-Amino Alkanols on Leishmania donovani
Authors: Abengózar María Ángeles , Bustos Luis A. , García-Hernández Raquel , Fernández de Palencia Pilar , Escarcena Ricardo , Castanys Santiago , del Olmo Esther , Gamarro Francisco , San Feliciano Arturo , Rivas Luis 
Published: December 2014

ABSTRACT

Leishmaniasis is the protozoan disease second in importance for human health, superseded only by malaria; however, the options for chemotherapeutic treatment are increasingly limited due to drug resistance and toxicity. Under this perspective, a quest for new chemical compounds is urgently needed. An N-substituted 2-aminoalkan-1-ol scaffold has been shown to be a versatile scaffold for antiparasitic activity. Knowledge about its mechanism of action is still rather limited. In this work, we endeavored to define the leishmanicidal profile of such β-amino alkanol derivatives using a set of 15 N-mono- and disubstituted surrogates, tested on
Leishmania donovani
promastigotes and intracellular amastigotes. The best compound (compound 5), 2-ethylaminododecan-1-ol, had a 50% effective concentration (EC
50
) of 0.3 μM and a selectivity index of 72 for infected THP-1 cells and was selected for further elucidation of its leishmanicidal mechanism. It induced fast depletion of intracellular ATP content in promastigotes in the absence of vital dye intracellular entry, ruling out plasma membrane permeabilization as its origin. Confocal and transmission electron microscopy analyses showed that compound 5 induced severe mitochondrial swelling and vesiculation. Polarographic analysis using an oxygen electrode demonstrated that complex II of the respiratory chain (succinate reductase) was strongly inhibited by compound 5, identifying this complex as one of the primary targets. Furthermore, for other β-amino alkanols whose structures differed subtly from that of compound 5, plasma membrane permeabilization or interference with membrane traffic was also observed. In all, N-substituted β-amino alkanols were shown as appealing leishmanicidal candidates deserving further exploration.
Genomic Insights into Intrinsic and Acquired Drug Resistance Mechanisms in Achromobacter xylosoxidans
Authors: Hu Yongfei , Zhu Yuying , Ma Yanan , Liu Fei , Lu Na , Yang Xi , Luan Chunguang , Yi Yong , Zhu Baoli 
Published: December 2014

ABSTRACT

Achromobacter xylosoxidans
is an opportunistic pathogen known to be resistant to a wide range of antibiotics; however, the knowledge about the drug resistance mechanisms is limited. We used a high-throughput sequencing approach to sequence the genomes of the
A. xylosoxidans
type strain ATCC 27061 and a clinical isolate,
A. xylosoxidans
X02736, and then we used different bioinformatics tools to analyze the drug resistance genes in these bacteria. We obtained the complete genome sequence for
A. xylosoxidans
ATCC 27061 and the draft sequence for X02736. We predicted a total of 50 drug resistance-associated genes in the type strain, including 5 genes for β-lactamases and 17 genes for efflux pump systems; these genes are also conserved among other
A. xylosoxidans
genomes. In the clinical isolate, except for the conserved resistance genes, we also identified several acquired resistance genes carried by a new transposon embedded in a novel integrative and conjugative element. Our study provides new insights into the intrinsic and acquired drug resistance mechanisms in
A. xylosoxidans
, which will be helpful for better understanding the physiology of
A. xylosoxidans
and the evolution of antibiotic resistance in this bacterium.
Pharmacokinetics of First-Line Antituberculosis Drugs in HIV-Infected Children with Tuberculosis Treated with Intermittent Regimens in India
Authors: Ramachandran Geetha , Kumar A. K. Hemanth , Bhavani P. K. , Kannan T. , Kumar S. Ramesh , Gangadevi N. Poorana , Banurekha V. V. , Sekar L. , Ravichandran N. , Mathevan G. , Sanjeeva G. N. , Dayal Rajeshwar , Swaminathan Soumya 
Published: December 2014

ABSTRACT

The objective of this report was to study the pharmacokinetics of rifampin (RMP), isoniazid (INH), and pyrazinamide (PZA) in HIV-infected children with tuberculosis (TB) treated with a thrice-weekly anti-TB regimen in the government program in India. Seventy-seven HIV-infected children with TB aged 1 to 15 years from six hospitals in India were recruited. During the intensive phase of TB treatment with directly observed administration of the drugs, a complete pharmacokinetic study was performed. Drug concentrations were measured by high-performance liquid chromatography. A multivariable regression analysis was done to explore the factors impacting drug levels and treatment outcomes. The proportions of children with subnormal peak concentrations (
C
max
) of RMP, INH, and PZA were 97%, 28%, and 33%, respectively. Children less than 5 years old had a lower median
C
max
and lower exposure (area under the time-concentration curve from 0 to 8 h [AUC
0–8
]) of INH (
C
max
, 2.5 versus 5.1 μg/ml, respectively [
P
= 0.016]; AUC
0–8
, 11.1 versus 22.0 μg/ml · h, respectively [
P
= 0.047[) and PZA (
C
max
, 34.1 versus 42.3 μg/ml, respectively [
P
= 0.055]; AUC
0–8
, 177.9 versus 221.7 μg/ml · h, respectively [
P
= 0.05]) than those more than 5 years old. In children with unfavorable versus favorable outcomes, the median
C
max
of RMP (1.0 versus 2.8 μg/ml, respectively;
P
= 0.002) and PZA (31.9 versus 44.4 μg/ml, respectively;
P
= 0.045) were significantly lower. Among all factors studied, the PZA
C
max
influenced TB treatment outcome (
P
= 0.011; adjusted odds ratio, 1.094; 95% confidence interval, 1.021 to 1.173). A high proportion of children with HIV and TB had a subnormal RMP
C
max
. The PZA
C
max
significantly influenced treatment outcome. These findings have important clinical implications and emphasize that drug doses in HIV-infected children with TB have to be optimized.
Complete Nucleotide Sequence of the IncN Plasmid Encoding IMP-6 and CTX-M-2 from Emerging Carbapenem-Resistant Enterobacteriaceae in Japan
Authors: Kayama Shizuo , Shigemoto Norifumi , Kuwahara Ryuichi , Oshima Kenshiro , Hirakawa Hideki , Hisatsune Junzo , Jové Thomas , Nishio Hisaaki , Yamasaki Katsutoshi , Wada Yasunao , Ueshimo Takeshi , Miura Tetsuya , Sueda Taijiro , Onodera Makoto , Yokozaki Michiya , Hattori Masahira , Ohge Hiroki , Sugai Motoyuki 
Published: December 2014

ABSTRACT

We have determined the DNA sequence of
Klebsiella pneumoniae
multidrug resistance plasmid pKPI-6, which is a self-transmissible IncN-type plasmid. pKPI-6 harboring
bla
IMP-6
and
bla
CTX-M-2
confers a stealth-type carbapenem resistance phenotype on members of the family
Enterobacteriaceae
that is not detectable with imipenem. pKPI-6 is already epidemic in Japan, favoring the dissemination of IMP-6 and CTX-M-2 in members of the family
Enterobacteriaceae
.
The Tyrosine Kinase BceF and the Phosphotyrosine Phosphatase BceD of Burkholderia contaminans Are Required for Efficient Invasion and Epithelial Disruption of a Cystic Fibrosis Lung Epithelial Cell Line
Authors: Ferreira Ana S. , Silva Inês N. , Fernandes Fábio , Pilkington Ruth , Callaghan Máire , McClean Siobhán , Moreira Leonilde M. 
Published: December 2014

ABSTRACT

Bacterial tyrosine kinases and their cognate protein tyrosine phosphatases are best known for regulating the biosynthesis of polysaccharides. Moreover, their roles in the stress response, DNA metabolism, cell division, and virulence have also been documented. The aim of this study was to investigate the pathogenicity and potential mechanisms of virulence dependent on the tyrosine kinase BceF and phosphotyrosine phosphatase BceD of the cystic fibrosis opportunistic pathogen
Burkholderia contaminans
IST408. The insertion mutants
bceD
::Tp and
bceF
::Tp showed similar attenuation of adhesion and invasion of the cystic fibrosis lung epithelial cell line CFBE41o- compared to the parental strain
B. contaminans
IST408. In the absence of
bceD
or
bceF
genes,
B. contaminans
also showed a reduction in the ability to translocate across polarized epithelial cell monolayers, demonstrated by a higher transepithelial electrical resistance, reduced flux of fluorescein isothiocyanate-labeled bovine serum albumin, and higher levels of tight junction proteins ZO-1, occludin, and claudin-1 present in monolayers exposed to these bacterial mutants. Furthermore,
bceD
::Tp and
bceF
::Tp mutants induced lower levels of interleukin-6 (IL-6) and IL-8 release than the parental strain. In conclusion, although the mechanisms of pathogenicity dependent on BceD and BceF are not understood, these proteins contribute to the virulence of
Burkholderia
by enhancement of cell attachment and invasion, disruption of epithelial integrity, and modulation of the proinflammatory response.
Expression Analysis of the Pseudomonas aeruginosa AlgZR Two-Component Regulatory System
Authors: Pritchett Christopher L. , Little Alexander S. , Okkotsu Yuta , Frisk Anders , Cody William L. , Covey Christopher R. , Schurr Michael J. 
Published: December 2014

ABSTRACT

Pseudomonas aeruginosa
virulence components are subject to complex regulatory control primarily through two-component regulatory systems that allow for sensing and responding to environmental stimuli. In this study, the expression and regulation of the
P. aeruginosa
AlgZR two-component regulatory system were examined. Primer extension and S1 nuclease protection assays were used to identify two transcriptional initiation sites for
algR
within the
algZ
coding region, and two additional start sites were identified upstream of the
algZ
coding region. The two
algR
transcriptional start sites, RT1 and RT2, are directly regulated by AlgU, consistent with previous reports of increased
algR
expression in mucoid backgrounds, and RpoS additionally plays a role in
algR
transcription. The expression of the first
algZ
promoter, ZT1, is entirely dependent upon Vfr for expression, whereas Vfr, RpoS, or AlgU does not regulate the second
algZ
promoter, ZT2. Western blot, real-time quantitative PCR (RT-qPCR), and transcriptional fusion analyses show that
algZR
expression is Vfr dependent. The
algZ
and
algR
genes also are cotranscribed in both nonmucoid and mucoid backgrounds. Furthermore,
algZR
was found to be cotranscribed with
hemCD
by RT-PCR. RT-qPCR confirmed that
hemC
transcription in the PAO1 Δ
algZ
mutant was 40% of the level of the wild-type strain. Taken together, these results indicate that
algZR
transcription involves multiple factors at multiple start sites that control individual gene expression as well as coexpression of this two-component system with heme biosynthetic genes.
Role of the Streptococcus mutans CRISPR-Cas Systems in Immunity and Cell Physiology
Authors: Serbanescu M. A. , Cordova M. , Krastel K. , Flick R. , Beloglazova N. , Latos A. , Yakunin A. F. , Senadheera D. B. , Cvitkovitch D. G. 
Published: December 2014

ABSTRACT

CRISPR-Cas systems provide adaptive microbial immunity against invading viruses and plasmids. The cariogenic bacterium
Streptococcus mutans
UA159 has two CRISPR-Cas systems: CRISPR1 (type II-A) and CRISPR2 (type I-C) with several spacers from both CRISPR cassettes matching sequences of phage M102 or genomic sequences of other
S. mutans
. The deletion of the
cas
genes of CRISPR1 (ΔC1S), CRISPR2 (ΔC2E), or both CRISPR1+2 (ΔC1SC2E) or the removal of spacers 2 and 3 (ΔCR1SP13E) in
S. mutans
UA159 did not affect phage sensitivity when challenged with virulent phage M102. Using plasmid transformation experiments, we demonstrated that the CRISPR1-Cas system inhibits transformation of
S. mutans
by the plasmids matching the spacers 2 and 3. Functional analysis of the
cas
deletion mutants revealed that in addition to a role in plasmid targeting, both CRISPR systems also contribute to the regulation of bacterial physiology in
S. mutans
. Compared to wild-type cells, the ΔC1S strain displayed diminished growth under cell membrane and oxidative stress, enhanced growth under low pH, and had reduced survival under heat shock and DNA-damaging conditions, whereas the ΔC2E strain exhibited increased sensitivity to heat shock. Transcriptional analysis revealed that the two-component signal transduction system VicR/K differentially modulates expression of
cas
genes within CRISPR-Cas systems, suggesting that VicR/K might coordinate the expression of two CRISPR-Cas systems. Collectively, we provide
in vivo
evidence that the type II-A CRISPR-Cas system of
S. mutans
may be targeted to manipulate its stress response and to influence the host to control the uptake and dissemination of antibiotic resistance genes.