bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New and Simple Concept to Replace “Film Effectiveness”
Authors: Adiutori Eugene F. 
Published: March 2015

Film effectiveness (η) is used to describe the adiabatic wall temperature (TAW) which results when a colder or hotter fluid is injected into the boundary layer. Eq (1) is the defining equation for η:(1)(TMS−TAW)=η(TMS−TF)where TF and TMS refer to the temperatures of the film and mainstream fluids.
Literature data indicate that η is a constant coefficient in Equation 1 only in applications where TF/TMS is restricted to a narrow band. If TF/TMS varies over a wide band, such as in gas turbines and rockets, then η is a variable in Eq 1.
This article demonstrates that, in applications where TF/TMS varies over a wide band, the film effectiveness concept is neither simple nor direct, and it complicates and confuses the solution of practical problems.
This article also presents a new and simple concept to replace film effectiveness. The new concept retains the TF/TMS parameter used in film effectiveness methodology, but it replaces η with TAW/TMS.
The particular advantage of the new concept is that it describes TAW in a simple and direct way even if TF/TMS varies over a wide band. The end result is that, in applications such as gas turbines and rockets, the new concept is much simpler and therefore much better than the film effectiveness concept it replaces.
A Low Noise Propulsion Concept for the Supersonic Transport
Authors: Champagne G. A. , Allen G. E. , Palmieri M. , Adler R. M. 
Published: March 2015

The major challenges with the design of propulsion systems for High speed Civil Transports (HSCT) are complying with FAR and EPA environmental standards while powering an economically acceptable aircraft. These issues create a dilemma in engine design because low exhaust jet velocities are required to meet takeoff noise regulations while high exhaust jet velocities are required for economical supersonic cruise operation. Previous studies have shown that to meet FAR Stage 3 noise regulations, engines incorporating mechanical/thermal noise suppression concepts must be oversized by 50 to 80% relative to the size that will provide the maximum aircraft economics.
In order to achieve the Stage 3 noise levels without oversizing the engine, the engine airflow must be increased by 120% during takeoff operation to reduce the average exhaust velocity to an acceptable level. This paper will examine a concept that brings in 74% additional airflow into the engine’s inlet and 46% into the engine’s exhaust nozzle. The impacts of this concept on engine design, performance, size and weight and on aircraft takeoff gross weight (TOGW) and range are evaluated. For the same TOGW aircraft, this noise reduction concept provides a 70% range improvement relative to engines which incorporate mechanical/thermal noise suppressors. This concept was developed under a NASA sponsored program.
Active Stabilization of Multistage Axial-Compressor Aerodynamic System Instabilities
Authors: Hosny W. M. , Leventhal L. , Steenken W. G. 
Published: March 2015

Active control of multistage axial-compressor aerodynamic instabilities has been studied analytically using a blade-row by blade-row compression system model. The instabilities considered are those which result from a global system instability. The control approach taken is to suppress the instability by actively changing the system damping characteristics. This was accomplished by varying dynamically the compressor stage characteristics to extend the region of the compression system operation. Specifically, the stator row of a compressor stage is actively dithered based on its inlet or exit pressure fluctuation measurement such that the stage characteristics are modified in such a way to improve the overall system stability.
The analytical model and the results of the stator dither study are presented in this paper. The results indicated a slight gain in the compressor stability limit line when the compressor stages are well matched. With increased interstage bleed, resulting in a mismatch between the front and the rear blocks of the compressor, the stabilization results indicated a significant gain in the stability limit line. In addition, the stator selection studies showed the importance of locating the active action near to and upstream of the stage where the system instability initiates.
Relationships Between Propulsion and Anthropometry in Paralympic Swimmers
Authors: Dingley Andrew A. , Pyne David B. , Burkett Brendan 
Published: March 2015

Purpose:To characterize relationships between propulsion, anthropometry, and performance in Paralympic swimming.Methods:A cross-sectional study of swimmers (13 male, 15 female) age 20.5 ± 4.4 y was conducted. Subject locomotor categorizations were no physical disability (n = 8, classes S13–S14) and low-severity (n = 11, classes S9–S10) or midseverity disability (n = 9, classes S6–S8). Full anthropometric profiles estimated muscle mass and body fat, a bilateral swim-bench ergometer quantified upper-body power production, and 100-m time trials quantified swimming performance.Results:Correlations between ergometer mean power and swimming performance increased with degree of physical disability (low-severity male r = .65, ±0.56, and female r = .68, ±0.64; midseverity, r = .87, ±0.41, and r = .79, ±0.75). The female midseverity group showed nearperfect (positive) relationships for taller swimmers’ (with a greater muscle mass and longer arm span) swimming faster, while for female no- and low-severity-disability groups, greater muscle mass was associated with slower velocity (r = .78, ±0.43, and r = .65, ±0.66). This was supported with lighter females (with less frontal surface area) in the low-severity group being faster (r = .94, ±0.24). In a gender contrast, low-severity males with less muscle mass (r = -.64, ±0.56), high skinfolds (r = .78, ±0.43), a longer arm span (r = .58, ±0.60) or smaller frontal surface area (r = -.93, ±0.19) were detrimental to swimming-velocity production.Conclusion:Low-severity male and midseverity female Paralympic swimmers should be encouraged to develop muscle mass and upper-body power to enhance swimming performance. The generalized anthropometric measures appear to be a secondary consideration for coaches.
Variability of PlayerLoad, Bowling Velocity, and Performance Execution in Fast Bowlers Across Repeated Bowling Spells
Authors: McNamara Dean J. , Gabbett Tim J. , Chapman Paul , Naughton Geraldine , Farhart Patrick 
Published: March 2015

Purpose:The use of wearable microtechnology to monitor the external load of fast bowling is challenged by the inherent variability of bowling techniques between bowlers. This study assessed the between-bowlers variability in PlayerLoad, bowling velocity, and performance execution across repeated bowling spells.Methods:Seven national-level fast bowlers completed two 6-over bowling spells at a batter during a competitive training session. Key dependent variables were PlayerLoad calculated with a MinimaxX microtechnology unit, ball velocity, and bowling execution based on a predetermined bowling strategy for each ball bowled. The between-bowlers coefficient of variation (CV), repeated-measures ANOVA, and smallest worthwhile change were calculated over the 2 repeated 6-over bowling spells and explored across 12-over, 6-over, and 3-over bowling segments.Results:From the sum of 6 consecutive balls, the between-bowlers CV for relative peak PlayerLoad was 1.2% over the 12-over bowling spell (P = .15). During this 12-over period, bowling-execution (P = .43) scores and ball-velocity (P = .31) CVs were calculated as 46.0% and 0.4%, respectively.Conclusions:PlayerLoad was found to be stable across the repeated bowling spells in the fast-bowling cohort. Measures of variability and change across the repeated bowling spells were consistent with the performance measure of ball velocity. The stability of PlayerLoad improved when assessed relative to the individual’s peak PlayerLoad. Only bowling-execution measures were found to have high variability across the repeated bowling spells. PlayerLoad provides a stable measure of external workload between fast bowlers.
Complete Sequence of a
bla
KPC
-Harboring Cointegrate Plasmid Isolated from Escherichia coli
Authors: Chavda Kalyan D. , Chen Liang , Jacobs Michael R. , Rojtman Albert D. , Bonomo Robert A. , Kreiswirth Barry N. 
Published: March 2015

ABSTRACT

Horizontal transfer of
bla
KPC
-harboring plasmids contributes significantly to the inter- and intraspecies spread of
Klebsiella pneumoniae
carbapenemase (KPC). Here we report the complete nucleotide sequence of a
bla
KPC
-harboring IncFIA plasmid, pBK32533, from
Escherichia coli
. pBK32533 is a cointegrate plasmid comprising of a 72-kb sequence identical to that of the nonconjugative pBK30661 plasmid plus an additional 170-kb element that harbors the genes for plasmid transfer. pBK32533 demonstrates how
bla
KPC
can be spread from a nonconjugative plasmid through cointegration.
β-Lactams Enhance Daptomycin Activity against Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium in
In Vitro
Pharmacokinetic/Pharmacodynamic Models
Authors: Smith Jordan R. , Barber Katie E. , Raut Animesh , Rybak Michael J. 
Published: March 2015

ABSTRACT

Enterococcus faecalis
and
Enterococcus faecium
are frequently resistant to vancomycin and β-lactams. In enterococcal infections with reduced glycopeptide susceptibility, combination therapy is often administered. Our objective was to conduct pharmacokinetic/pharmacodynamic (PK/PD) models to evaluate β-lactam synergy with daptomycin (DAP) against resistant enterococci. One
E. faecalis
strain (R6981) and two
E. faecium
strains (R6370 and 8019) were evaluated. DAP MICs were obtained. All strains were evaluated for response to LL37, an antimicrobial peptide, in the presence and absence of ceftaroline (CPT), ertapenem (ERT), and ampicillin (AMP). After 96 h,
in vitro
models were run simulating 10 mg DAP/kg body weight/day, 600 mg CPT every 8 h (q8h), 2 g AMP q4h, and 1 g ERT q24h, both alone and in combination against all strains. DAP MICs were 2, 4, and 4 μg/ml for strains R6981, R6370, and 8019, respectively. PK/PD models demonstrated bactericidal activity with DAP-CPT, DAP-AMP, and DAP-ERT combinations against strain 8019 (
P
< 0.001 and log
10
CFU/ml reduction of >2 compared to any single agent). Against strains R6981 and R6370, the DAP-AMP combination demonstrated enhancement against R6370 but not R6981, while the combinations of DAP-CPT and DAP-ERT were bactericidal, demonstrated enhancement, and were statistically superior to all other regimens at 96 h (
P
< 0.001) against both strains. CPT, ERT, and AMP similarly augmented LL37 killing against strain 8019. In strains R6981 and R6370, CPT and ERT aided LL37 more than AMP (
P
< 0.001). Compared to DAP alone, combination regimens provide better killing and prevent resistance. Clinical research involving DAP combinations is warranted.
A Putative Cro-Like Repressor Contributes to Arylomycin Resistance in Staphylococcus aureus
Authors: Craney Arryn , Romesberg Floyd E. 
Published: March 2015

ABSTRACT

Antibiotic-resistant bacteria are a significant public health concern and motivate efforts to develop new classes of antibiotics. One such class of antibiotics is the arylomycins, which target type I signal peptidase (SPase), the enzyme responsible for the release of secreted proteins from their N-terminal leader sequences. Despite the essentiality, conservation, and relative accessibility of SPase, the activity of the arylomycins is limited against some bacteria, including the important human pathogen
Staphylococcus aureus
. To understand the origins of the limited activity against
S. aureus
, we characterized the susceptibility of a panel of strains to two arylomycin derivatives, arylomycin A-C
16
and its more potent analog arylomycin M131. We observed a wide range of susceptibilities to the two arylomycins and found that resistant strains were sensitized by cotreatment with tunicamycin, which inhibits the first step of wall teichoic acid synthesis. To further understand how
S. aureus
responds to the arylomycins, we profiled the transcriptional response of
S. aureus
NCTC 8325 to growth-inhibitory concentrations of arylomycin M131 and found that it upregulates the cell wall stress stimulon (CWSS) and an operon consisting of a putative transcriptional regulator and three hypothetical proteins. Interestingly, we found that mutations in the putative transcriptional regulator are correlated with resistance, and selection for resistance
ex vivo
demonstrated that mutations in this gene are sufficient for resistance. The results begin to elucidate how
S. aureus
copes with secretion stress and how it evolves resistance to the inhibition of SPase.
Fungal β-1,3-Glucan Increases Ofloxacin Tolerance of Escherichia coli in a Polymicrobial E. coli/Candida albicans Biofilm
Authors: De Brucker Katrijn , Tan Yulong , Vints Katlijn , De Cremer Kaat , Braem Annabel , Verstraeten Natalie , Michiels Jan , Vleugels Jef , Cammue Bruno P. A. , Thevissen Karin 
Published: March 2015

ABSTRACT

In the past, biofilm-related research has focused mainly on axenic biofilms. However, in nature, biofilms are often composed of multiple species, and the resulting polymicrobial interactions influence industrially and clinically relevant outcomes such as performance and drug resistance. In this study, we show that
Escherichia coli
does not affect
Candida albicans
tolerance to amphotericin or caspofungin in an
E. coli/C. albicans
biofilm. In contrast, ofloxacin tolerance of
E. coli
is significantly increased in a polymicrobial
E. coli
/
C. albicans
biofilm compared to its tolerance in an axenic
E. coli
biofilm. The increased ofloxacin tolerance of
E. coli
is mainly biofilm specific, as ofloxacin tolerance of
E. coli
is less pronounced in polymicrobial
E. coli/C. albicans
planktonic cultures. Moreover, we found that ofloxacin tolerance of
E. coli
decreased significantly when
E. coli/C. albicans
biofilms were treated with matrix-degrading enzymes such as the β-1,3-glucan-degrading enzyme lyticase. In line with a role for β-1,3-glucan in mediating ofloxacin tolerance of
E. coli
in a biofilm, we found that ofloxacin tolerance of
E. coli
increased even more in
E. coli/C. albicans
biofilms consisting of a high-β-1,3-glucan-producing
C. albicans
mutant. In addition, exogenous addition of laminarin, a polysaccharide composed mainly of poly-β-1,3-glucan, to an
E. coli
biofilm also resulted in increased ofloxacin tolerance. All these data indicate that β-1,3-glucan from
C. albicans
increases ofloxacin tolerance of
E. coli
in an
E. coli/C. albicans
biofilm.
Complete Nucleotide Sequences of
bla
CTX-M
-Harboring IncF Plasmids from Community-Associated Escherichia coli Strains in the United States
Authors: Li Jun-Jie , Spychala Caressa N. , Hu Fupin , Sheng Ji-Fang , Doi Yohei 
Published: March 2015

ABSTRACT

Community-associated infections due to
Escherichia coli
producing CTX-M-type extended-spectrum β-lactamases are increasingly recognized in the United States. The
bla
CTX-M
genes are frequently carried on IncF group plasmids. In this study,
bla
CTX-M-15
-harboring plasmids pCA14 (sequence type 131 [ST131]) and pCA28 (ST44) and
bla
CTX-M-14
-harboring plasmid pCA08 (ST131) were sequenced and characterized. The three plasmids were closely related to other IncFII plasmids from continents outside the United States in the conserved backbone region and multiresistance regions (MRRs). Each of the
bla
CTX-M-15
-carrying plasmids pCA14 and pCA28 belonged to F31:A4:B1 (FAB [FII, FIA, FIB] formula) and showed a high level of similarity (92% coverage of pCA14 and 99% to 100% nucleotide identity), suggesting a possible common origin. The
bla
CTX-M-14
-carrying plasmid pCA08 belonged to F2:A2:B20 and was highly similar to pKF3-140 from China (88% coverage of pCA08 and 99% to 100% nucleotide identity). All three plasmids carried multiple antimicrobial resistance genes and modules associated with virulence and biochemical pathways, which likely confer selective advantages for their host strains. The
bla
CTX-M
-carrying IncFII-IA-IB plasmids implicated in community-associated infections in the United States shared key structural features with those identified from other continents, underscoring the global nature of this plasmid epidemic.
Efficacy of the Investigational Echinocandin ASP9726 in a Guinea Pig Model of Invasive Pulmonary Aspergillosis
Authors: Wiederhold Nathan P. , Najvar Laura K. , Matsumoto Satoru , Bocanegra Rosie A. , Herrera Monica L. , Wickes Brian L. , Kirkpatrick William R. , Patterson Thomas F. 
Published: March 2015

ABSTRACT

ASP9726 is an investigational echinocandin with
in vitro
activity against
Aspergillus
species. We evaluated the pharmacokinetics and efficacy of this agent in an established guinea pig model of invasive pulmonary aspergillosis. ASP9726 plasma concentrations were measured in guinea pigs administered either a single dose or multiple doses of this agent at 2.5, 5, and 10 mg/kg of body weight/day by subcutaneous injection. Immunosuppressed guinea pigs were inoculated with
A. fumigatus
AF293, and ASP9726 (2.5, 5, and 10 mg/kg/day), voriconazole (10 mg/kg by oral gavage twice daily), or caspofungin (3 mg/kg/day by intraperitoneal injection) was administered for 8 days. Changes in fungal burden were measured by enumerating CFU and by quantitative PCR of specimens from within the lungs, as well as by analysis of serum (1→3)-β-
d
-glucan and galactomannan. Lung histopathology was also evaluated. ASP9726 plasma concentrations increased in a dose-proportional manner, and the drug was well tolerated at each dose. Each dose of ASP9726, voriconazole, and caspofungin significantly reduced pulmonary fungal burden as measured by quantitative PCR and by determining (1→3)-β-
d
-glucan and galactomannan levels, but only voriconazole significantly reduced numbers of CFU. ASP9726 at 5 mg/kg also significantly improved survival. Histopathology demonstrated morphological changes in hyphae in animals exposed to ASP9726 and caspofungin, consistent with the activities of the echinocandins. These results suggest that ASP9726 may be efficacious for the treatment of invasive pulmonary aspergillosis.
Potential of Novel Antimicrobial Peptide P3 from Bovine Erythrocytes and Its Analogs To Disrupt Bacterial Membranes
In Vitro
and Display Activity against Drug-Resistant Bacteria in a Mouse Model
Authors: Zhang Qinghua , Xu Yanzhao , Wang Qing , Hang Bolin , Sun Yawei , Wei Xiaoxiao , Hu Jianhe 
Published: March 2015

ABSTRACT

With the emergence of many antibiotic-resistant strains worldwide, antimicrobial peptides (AMPs) are being evaluated as promising alternatives to conventional antibiotics. P3, a novel hemoglobin peptide derived from bovine erythrocytes, exhibited modest antimicrobial activity
in vitro
. We evaluated the antimicrobial activities of P3 and an analog, JH-3, both
in vitro
and
in vivo
. The MICs of P3 and JH-3 ranged from 3.125 μg/ml to 50 μg/ml when a wide spectrum of bacteria was tested, including multidrug-resistant strains. P3 killed bacteria within 30 min by disrupting the bacterial cytoplasmic membrane and disturbing the intracellular calcium balance. Circular dichroism (CD) spectrometry showed that P3 assumed an α-helical conformation in bacterial lipid membranes, which was indispensable for antimicrobial activity. Importantly, the 50% lethal dose (LD
50
) of JH-3 was 180 mg/kg of mouse body weight after intraperitoneal (i.p.) injection, and no death was observed at any dose up to 240 mg/kg body weight following subcutaneous (s.c.) injection. Furthermore, JH-3 significantly decreased the bacterial count and rescued infected mice in a model of mouse bacteremia. In conclusion, P3 and an analog exhibited potent antimicrobial activities and relatively low toxicities in a mouse model, indicating that they may be useful for treating infections caused by drug-resistant bacteria.
Photochemotherapeutic Strategy against Acanthamoeba Infections
Authors: Aqeel Yousuf , Siddiqui Ruqaiyyah , Anwar Ayaz , Shah Muhammad Raza , Khoja Shahrukh , Khan Naveed Ahmed 
Published: March 2015

ABSTRACT

Acanthamoeba
is a protist pathogen that can cause serious human infections, including blinding keratitis and a granulomatous amoebic encephalitis that almost always results in death. The current treatment for these infections includes a mixture of drugs, and even then, a recurrence can occur. Photochemotherapy has shown promise in the treatment of
Acanthamoeba
infections; however, the selective targeting of pathogenic
Acanthamoeba
has remained a major concern. The mannose-binding protein is an important adhesin expressed on the surface membranes of pathogenic
Acanthamoeba
organisms. To specifically target
Acanthamoeba
, the overall aim of this study was to synthesize a photosensitizing compound (porphyrin) conjugated with mannose and test its efficacy
in vitro
. The synthesis of mannose-conjugated porphyrin was achieved by mixing benzaldehyde and pyrrole, yielding tetraphenylporphyrin. Tetraphenylporphyrin was then converted into mono-nitrophenylporphyrin by selectively nitrating the
para
position of the phenyl rings, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. The mono-nitrophenylporphyrin was reduced to mono-aminophenylporphyrin in the presence of tin dichloride and confirmed by a peak at
m/z
629. Finally, mono-aminoporphyrin was conjugated with mannose, resulting in the formation of an imine bond. Mannose-conjugated porphyrin was confirmed through spectroscopic analysis and showed that it absorbed light of wavelengths ranging from 425 to 475 nm. To determine the antiacanthamoebic effects of the derived product, amoebae were incubated with mannose-conjugated porphyrin for 1 h and washed 3 times to remove extracellular compound. Next, the amoebae were exposed to light of the appropriate wavelength for 1 h. The results revealed that mannose-conjugated porphyrin produced potent trophicidal effects and blocked excystation. In contrast,
Acanthamoeba castellanii
incubated with mannose alone and porphyrin alone did not exhibit an antiamoebic effect. Consistently, pretreatment with mannose-conjugated porphyrin reduced the
A. castellanii
-mediated host cell cytotoxicity from 97% to 4.9%. In contrast, treatment with porphyrin, mannose, or solvent alone had no protective effects on the host cells. These data suggest that mannose-conjugated porphyrin has application for the targeted photodynamic therapy of
Acanthamoeba
infections and may serve as a model in the development of therapeutic interventions against other eukaryotic infections.