bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurements of Heat Transfer Coefficients From Supercritical Carbon
Dioxide Flowing in Horizontal Mini/Micro Channels
Authors: Liao S. M. , Zhao T. S. 
Published: July 2002

Abstract
Heat transfer from supercritical carbon dioxide flowing in horizontal mini/micro circular tubes cooled at a constant temperature has been investigated experimentally. Six stainless steel circular tubes having inside-diameters of 0.50 mm, 0.70 mm, 1.10 mm, 1.40 mm, 1.55 mm, and 2.16 mm were tested. Measurements were carried out for the pressures ranging from 74 to 120 bar, the temperatures ranging from 20 to 110°C, and the mass flow rates ranging from 0.02 to 0.2 kg/min. It is found that the buoyancy effect was still significant, although supercritical CO2 was in forced motion through the horizontal tubes at Reynolds numbers up to 105. The experimental results also indicate that the existing correlations developed in the previous studies for large tubes deviate significantly from the experimental data for the present mini/micro tubes. Based on the experimental data, a correlation was developed for the axially averaged Nusselt number in terms of appropriate dimensionless parameters for forced convection of supercritical carbon dioxide in horizontal mini/micro tubes cooled at a constant temperature.
A Comprehensive Model to Predict Three-Way Catalytic Converter Performance
Authors: Shamim T. , Shen H. , Sengupta S. , Son S. , Adamczyk A. A. 
Published: July 2002

AbstractThis paper describes the development of a comprehensive mathematical and numerical model for simulating the performance of automotive three-way catalytic converters, which are employed to reduce engine exhaust emissions. The model simulates the emission system behavior by using an exhaust system heat conservation and catalyst chemical kinetic submodel. The resulting governing equations are solved numerically. Good agreements were found between the numerical predictions and experimental measurements under both steady-state and transient conditions. The developed model will be used to facilitate the converter design improvement efforts, which are necessary in order to meet the increasingly stricter emission requirements.
Allocating the Causes of Performance Deterioration in Combined Cycle Gas Turbine Plants
Authors: Mathioudakis K. , Stamatis A. , Bonataki E. 
Published: July 2002

AbstractA method for defining which parts of a combined cycle gas turbine (CCGT) power plant are responsible for performance deviations is presented. When the overall performances deviate from their baseline values, application of the method allows the determination of the component(s) of the plant, responsible for this deviation. It is shown that simple differentiation approaches may lead to erroneous conclusions, because they do not reveal the nature of deviations for individual components. Contributions of individual components are then assessed by separating deviations due to permanent changes and deviations due to change of operating conditions. A generalized formulation is presented together with the way of implementing it. Test cases are given, to make clearer the ideas put forward in the proposed method.
Stick-slip Whirl Interaction in Drillstring Dynamics
Authors: Leine R. I. , van Campen D. H. , Keultjes W. J. G. 
Published: July 2002

Abstract
This paper attempts to explain the complicated behavior of oilwell drillstring motion when both torsional stick-slip and lateral whirl vibration are involved. It is demonstrated that the observed phenomena in experimental drillstring data could be due to the fluid forces of the drilling mud. A Stick-slip Whirl Model is presented which consists of a submodel for the whirling motion and a submodel for the stick-slip motion, both as simple as possible. The Stick-slip Whirl Model is a simplification of a drillstring confined in a borehole wall with drilling mud. The model is as simple as possible to expose only the basic phenomena but is discontinuous. Bifurcation diagrams of this discontinuous model for varying rotation speeds reveal discontinuous bifurcations. The disappearance of stick-slip vibration when whirl vibration appears is explained by bifurcation theory. The numerical results are compared with the experimental data from a full-scale drilling rig.
Reactive ion etching related Si surface residues and subsurface damage: Their relationship to fundamental etching mechanisms
Authors: Oehrlein Gottlieb S. , Lee Young H. 
Published: July 2002

The role of silicon near-surface modifications caused by reactive ion etching in obtaining oxide-to-silicon etch selectivity has been studied by combining Si etch rate and plasma optical emission spectroscopy data with results from the analysis of etched Si surfaces. The nature of the near-surface modifications was established from the study of Si crystals subjected to overetching during CF4/x% H2 selective reactive ion etching of SiO2 on Si. The experimental techniques used included x-ray photoemission spectroscopy, He ion channeling, nuclear reaction techniques, and ellipsometry. Impurity penetration has been verified by nondestructive depth profiling using nuclear reaction and angular dependent core level photoemission techniques. Fluorocarbon film deposition, a highly disordered near-surface region (∼30 Å), and etching gas related impurity penetration into the Si lattice are among the Si substrate modifications observed. By nuclear reaction analysis, hydrogen at concentrations of the order 0.1 at. % has been detected at a depth of several 100 Å from the Si surface. By substituting deuterium for hydrogen in reactive ion etching and conducting secondary ion mass spectroscopy, deuterium at concentrations greater than 1017 atoms/cm3 has been detected more than 2000 Å from the Si surface after 1 min plasma exposure.
Direct observation of silicon–carbon bonds and silicon–hydrogen bonding in the modified Si layer was possible by photoemission and Raman scattering. The function of the Si near-surface modifications in the reactive ion etching process, specifically their role in achieving oxide-to-Si etch selectivity, has been elucidated. The etch rate of silicon is controlled by the thickness of the fluorocarbon layer on the silicon surface. It is consistent with a diffusion limited supply of F across the C,F film to the Si/C,F film interface and/or outdiffusion of etch product. The Si subsurface modifications, e.g., lattice disorder and impurities, do not contribute to the decrease of the Si etch rate; reactive ion etching (RIE) process modifications which minimize damage to the Si substrate are therefore discussed. Our results also demonstrate directly the recombinant/passivant model of etch anisotropy for the CF4/H2 RIE-Si etching system. Anisotropic etching of Si in a CF4/H2 plasma occurs via ion bombardment mediated C,F-layer thickness control. Energetic ion bombardment minimizes the thickness of the C,F layer and Si etching can proceed. Areas exposed to little ion bombardment (sidewalls) are covered by thicker C,F layers and no Si etching occurs.
Biotechnology: The Genomics Gamble
Authors: Cohen Jon 
Published: July 2002

Drug companies, biotechs, and Wall Street investors are putting their money down on efforts to unlock the secrets of human DNA. But when will genomics deliver on its promise of next-generation drugs and treatments?
RELATED WEB SITES:

http://www.ornl.gov/sci/techresources/Human_Genome/home.html
A U.S. government-maintained Web page for news, policy guidelines, and ethics discussions centered on the international Human Genome Project.

http://www3.techstocks.com/~wsapi/investor/stocktalk-10
A private site where small investors chat, often with scant insight, about a wide variety of biotech stocks.

http://www.tradesmart.com/rumor/
The Biotech Rumor Mill, a gossip zone about biotech companies, much of it anonymous. (See the
site review
in Science's Next Wave.)

http://www.recap.com/
Recombinant Capital, a San Francisco consulting group directed by Mark Edwards. With detailed analytical information on biotech companies, their capitalization, and past press releases.

http://www.sec.gov/cgi-bin/srch-edgar
The U.S. Securities and Exchange Commission's search engine for looking up recent disclosures filed by public companies.
In Vitro Antihepadnaviral Activities of Combinations of Penciclovir, Lamivudine, and Adefovir
Authors: Colledge Danni , Civitico Gilda , Locarnini Stephen , Shaw Tim 
Published: July 2002

ABSTRACTPenciclovir {9-[2-hydroxy-1-(hydroxymethyl)-ethoxymethyl]guanine [PCV]}, lamivudine ([−]-β-l-2′,3′-dideoxy-3′-thiacytidine [3TC]), and adefovir (9-[2-phosphonylmethoxyethyl]-adenine [PMEA]) are potent inhibitors of hepatitis B virus (HBV) replication. Lamivudine has recently received approval for clinical use against chronic human HBV infection, and both PCV and PMEA have undergone clinical trials against HBV in their respective prodrug forms {famciclovir and adefovir dipivoxil [bis-(POM)-PMEA]}. Since multidrug combinations are likely to be used to control HBV infection, investigation of potential interactions between PCV, 3TC, and PMEA is important. Primary duck hepatocyte cultures which were either acutely or congenitally infected with the duck hepatitis B virus (DHBV) were used to investigate in vitro interactions between PCV, 3TC, and PMEA. Here we show that the anti-DHBV effects of all the combinations containing PCV, 3TC, and PMEA are greater than that of each of the individual components and that their combined activities are approximately additive or synergistic. These results may underestimate the potential in vivo usefulness of PMEA-containing combinations, since there is evidence that PMEA has immunomodulatory activity and, at least in the duck model of chronic HBV infection, is capable of inhibiting DHBV replication in cells other than hepatocytes, the latter being unaffected by treatment with either PCV or 3TC. Further investigation of the antiviral activities of these drug combinations is therefore required, particularly since each of the component drugs is already in clinical use.
Mutations in
Plasmodium falciparum
Cytochrome
b
That Are Associated with Atovaquone Resistance Are Located at a Putative Drug-Binding Site
Authors: Korsinczky Michael , Chen Nanhua , Kotecka Barbara , Saul Allan , Rieckmann Karl , Cheng Qin 
Published: July 2002

ABSTRACT

Atovaquone is the major active component of the new antimalarial drug Malarone. Considerable evidence suggests that malaria parasites become resistant to atovaquone quickly if atovaquone is used as a sole agent. The mechanism by which the parasite develops resistance to atovaquone is not yet fully understood. Atovaquone has been shown to inhibit the cytochrome
bc
1
(CYT
bc
1
) complex of the electron transport chain of malaria parasites. Here we report point mutations in
Plasmodium falciparum
CYT
b
that are associated with atovaquone resistance. Single or double amino acid mutations were detected from parasites that originated from a cloned line and survived various concentrations of atovaquone in vitro. A single amino acid mutation was detected in parasites isolated from a recrudescent patient following atovaquone treatment. These mutations are associated with a 25- to 9,354-fold range reduction in parasite susceptibility to atovaquone. Molecular modeling showed that amino acid mutations associated with atovaquone resistance are clustered around a putative atovaquone-binding site. Mutations in these positions are consistent with a reduced binding affinity of atovaquone for malaria parasite CYT
b
.
The Ovine Cathelicidin SMAP29 Kills Ovine Respiratory Pathogens In Vitro and in an Ovine Model of Pulmonary Infection
Authors: Brogden K. A. , Kalfa V. C. , Ackermann M. R. , Palmquist D. E. , McCray P. B. , Tack B. F. 
Published: July 2002

ABSTRACT

Cathelicidins are antimicrobial peptides from sheep (SMAP29 and SMAP34), rabbits (CAP11 and CAP18), rodents (CRAMP), and humans (FALL39, LL37, and h/CAP18). In a broth microdilution assay against nine ovine pathogens, SMAP29, SMAP34, mouse CRAMP, CAP18, CAP18
31
, CAP18
28
, CAP18
22
, and CAP18
21a
were the most active, with MICs as low as 0.6 μg/ml. Other cathelicidins were less active. In lambs with pneumonia, 0.5 mg of SMAP29 reduced the concentration of bacteria in both bronchoalveolar lavage fluid and consolidated pulmonary tissues. Hence, the antimicrobial activity of SMAP29 suggests that it has applications in the treatment of respiratory tract infections.
In Vitro Killing of
Candida albicans
by Fatty Acids and Monoglycerides
Authors: Bergsson Gudmundur , Arnfinnsson Jóhann , Steingrı́msson Ólafur , Thormar Halldor 
Published: July 2002

ABSTRACT

The susceptibility of
Candida albicans
to several fatty acids and their 1-monoglycerides was tested with a short inactivation time, and ultrathin sections were studied by transmission electron microscopy (TEM) after treatment with capric acid. The results show that capric acid, a 10-carbon saturated fatty acid, causes the fastest and most effective killing of all three strains of
C. albicans
tested, leaving the cytoplasm disorganized and shrunken because of a disrupted or disintegrated plasma membrane. Lauric acid, a 12-carbon saturated fatty acid, was the most active at lower concentrations and after a longer incubation time.
Multidrug Resistance Is Mediated by Large Plasmids Carrying a Class 1 Integron in the Emergent
Salmonella enterica
Serotype [4,5,12:i:−]
Authors: Guerra Beatriz , Soto Sara M. , Argüelles Jose M. , Mendoza M. Carmen 
Published: July 2002

ABSTRACT

A multidrug-resistant
Salmonella enterica
serotype [4,5,12:i:−] clone carried a class 1 integron harboring
dfrA12
and
aadA2
gene cassettes and
bla
TEM-1
,
aac(3)-IV
,
cmlA1
, and
tetA
genes located in large plasmids of about 140 kb (carrying
spv
) or 120 kb (lacking
spv
). Several segregants, lacking multidrug resistance, contained a plasmid smaller than the parental one and no longer hybridized with probes for the lost resistances. The genes mediating resistance to ampicillin, chloramphenicol, and tetracycline in the [4,5,12:i:−] clone are different from those found in the pentadrug-resistant serotype Typhimurium DT104 clone.
Single- and Multiple-Dose Pharmacokinetics of Caspofungin in Healthy Men
Authors: Stone Julie A. , Holland Sherry D. , Wickersham Peter J. , Sterrett Andrew , Schwartz Michael , Bonfiglio Cynthia , Hesney Michael , Winchell Gregory A. , Deutsch Paul J. , Greenberg Howard , Hunt Thomas L. , Waldman Scott A. 
Published: July 2002

ABSTRACT

Caspofungin, a glucan synthesis inhibitor, is being developed as a parenteral antifungal agent. The pharmacokinetics of caspofungin following 1-h intravenous infusions in healthy men was investigated in four phase I studies. In an alternating two-panel (six men each), rising-single-dose study, plasma drug concentrations increased proportionally with the dose following infusions of 5 to 100 mg. The β-phase half-life was 9 to 10 h. The plasma drug clearance rate averaged 10 to 12 ml/min. Renal clearance of unchanged drug was a minor pathway of elimination (∼2% of the dose). Multiple-dose pharmacokinetics were investigated in a 2-week, serial-panel (5 or 6 men per panel) study of doses of 15, 35, and 70 mg administered daily; a 3-week, single-panel (10 men) study of a dose of 70 mg administered daily; and a parallel panel study (8 men) of a dose of 50 mg administered daily with or without a 70-mg loading dose on day 1. Moderate accumulation was observed with daily dosing. The degree of drug accumulation and the time to steady state were somewhat dose dependent. Accumulation averaged 24% at 15 mg daily and ∼50% at 50 and 70 mg daily. Mean plasma drug concentrations were maintained above 1.0 μg/ml, a target selected to exceed the MIC at which 90% of the isolates of the most clinically relevant species of
Candida
were inhibited, throughout therapy with daily treatments of 70 or 50 mg plus the loading dose, while they fell below the target for the first 2 days of a daily treatment of 50 mg without the loading dose. Caspofungin infused intravenously as a single dose or as multiple doses was generally well tolerated. In conclusion, the pharmacokinetics of caspofungin supports the clinical evaluation of once-daily dosing regimens for efficacy against fungal infections.
Characterization of Wild-Type and Cidofovir-Resistant Strains of Camelpox, Cowpox, Monkeypox, and Vaccinia Viruses
Authors: Smee Donald F. , Sidwell Robert W. , Kefauver Debbie , Bray Mike , Huggins John W. 
Published: July 2002

ABSTRACTCidofovir {[(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine] [HPMPC]}-resistant forms of camelpox, cowpox, monkeypox, and vaccinia viruses were developed by prolonged passage in Vero 76 cells in the presence of drug. Eight- to 27-fold-higher concentrations of cidofovir were required to inhibit the resistant viruses than were needed to inhibit the wild-type (WT) viruses. Resistant viruses were characterized by determining their cross-resistance to other antiviral compounds, examining their different replication abilities in two cell lines, studying the biochemical basis of their drug resistance, and assessing the degrees of their virulence in mice. These viruses were cross resistant to cyclic HPMPC and, with the exception of vaccinia virus, to (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)adenine. Three of the four resistant cowpox and monkeypox viruses exhibited reduced abilities to infect and replicate in 3T3 cells compared to their abilities in Vero 76 cells. Compared to the WT virus polymers the resistant cowpox virus DNA polymerase was 8.5-fold less sensitive to inhibition by cidofovir diphosphate, the active form of the drug. Intracellular phosphorylation of [3H]cidofovir was not stimulated or inhibited by infection with resistant cowpox virus. In intranasally infected BALB/c mice, WT cowpox virus was 80-fold more virulent than the resistant virus. Cidofovir treatment (100 mg/kg of body weight, given one time only as early as 5 min after virus challenge) of a resistant cowpox virus infection could not protect mice from mortality. However, the drug prevented mortality in 80 to 100% of the mice treated with a single 100-mg/kg dose at 1, 2, 3, or 4 days after WT virus challenge. By application of these results to human orthopoxvirus infections, it is anticipated that resistant viruses may be untreatable with cidofovir but their virulence may be attenuated. Studies will need to be conducted with cidofovir-resistant monkeypox virus in monkeys to further support these hypotheses.
Development of 16S rRNA-Based Probes for the
Coriobacterium
Group and the
Atopobium
Cluster and Their Application for Enumeration of
Coriobacteriaceae
in Human Feces from Volunteers of Different Age Groups
Authors: Harmsen Hermie J. M. , Wildeboer-Veloo Alida C. M. , Grijpstra Jan , Knol Jan , Degener John E. , Welling Gjalt W. 
Published: July 2002

ABSTRACT

Two 16S rRNA-targeted probes were developed: one for the
Coriobacterium
group and the other for the
Atopobium
cluster (which comprises most of the
Coriobacteriaceae
species, including the
Coriobacterium
group). The new probes were based on sequences of three new
Coriobacteriaceae
strains isolated from human feces and clinical material and sequences from databases. Application of the probes to fecal samples showed that formula-fed infants had higher numbers of
Coriobacterium
group cells in their feces than breast-fed infants. In addition, based on the presented results, it is hypothesized that with the increasing age of a person, the diversity of
Atopobium
cluster species present in the feces increases.
Microscale Diversity of the GenusNitrobacterin Soil on the Basis of Analysis of Genes Encoding rRNA
Authors: Grundmann G. L. , Normand P. 
Published: July 2002

ABSTRACTWe looked at the diversity of NO2−oxidizers at field scale by examining isolates at clump scale and in microsamples of soil (diameter, 50 μm). The genetic distances (as determined by amplified ribosomal DNA restriction analysis performed withNitrobacter-specific primers) in a small clump of soil were as large as those between reference strains from large geographical areas. Diversity in individual microsamples was shown by serotyping.
Isolation and Characterization of aHelicobactersp. from the Gastric Mucosa of Dolphins,Lagenorhynchus acutusandDelphinus delphis
Authors: Harper Claudia M. G. , Dangler Charles A. , Xu Shilu , Feng Yan , Shen Zeli , Sheppard Barbara , Stamper Andrew , Dewhirst Floyd E. , Paster Bruce J. , Fox James G. 
Published: July 2002

ABSTRACTGastric ulcerations in dolphins have been reported for decades. Some of these lesions were associated with parasitic infections. However, cases of nonparasitic gastric ulcers with no clearly defined etiology also have been reported in wild and captive dolphins. Considerable speculation exists as to whether dolphins haveHelicobacter-associated gastritis and peptic ulcer disease. The stomachs of seven stranded Atlantic white-sided dolphins,Lagenorhynchus acutus, and 1 common dolphin,Delphinus delphis, were assessed for the presence ofHelicobacterspecies. NovelHelicobacterspecies were identified by culture in the gastric mucosa of two of the eight dolphins studied and by PCR in seven of the eight dolphins. The gram-negative organisms were urease, catalase, and oxidase positive. Spiral to fusiform bacteria were detected in gastric mucosa by Warthin Starry staining. Histopathology revealed mild to moderate diffuse lymphoplasmacytic gastritis within the superficial mucosa of the main stomach. The pyloric stomach was less inflamed, and bacteria did not extend deep into the glands. The lesions parallel those observed inHelicobacter pylori-infected humans. Bacteria from two dolphins classified by 16S rRNA analysis clustered with gastric helicobacters and represent a novelHelicobactersp. most closely related toH. pylori. These findings suggest that a novelHelicobactersp. may play a role in the etiopathogenesis of gastritis and gastric ulcers in dolphins. To our knowledge this represents the first isolation and characterization of a novelHelicobactersp. from a marine mammal and emphasizes the wide host distribution and pathogenic potential of this increasingly important genus.
Characterization and Chromosomal Mapping of Antimicrobial Resistance Genes inSalmonella entericaSerotype Typhimurium
Authors: Daly M. , Fanning S. 
Published: July 2002

ABSTRACTTwo hundred and twenty-sixSalmonella entericaserotype Typhimurium isolates were examined for the presence of integron-associated gene cassettes. All but two of the non-DT104 isolates, together with DT104 isolates, contained gene cassettes. Amplicons of 1.5 kbp each were found in two non-DT104 isolates, encoding adhfrIgene (trimethoprim resistance) linked to anaadAgene (streptomycin and spectinomycin resistance), by site-specific recombination. DT104 isolates of resistance (R) type ACSSuT possessed the recently described 1.0- and 1.2-kbp gene cassettes. Macrorestriction analysis withXbaI and DNA probing mappedant(3")-1a,blaPSE-1, anddhfrIgenes to large multiresistant gene clusters in a DT170a isolate and a DT193 isolate. In contrast, all DT104 isolates (R-type ACSSuT) possessed a conserved 10-kbpXba1DNA fragment. Our study highlights the occurrence of integrons (and antimicrobial resistance determinants) among serotype Typhimurium isolates other than DT104. Larger and previously unrecognized multiresistance gene clusters were identified in these isolates by DNA probing.