bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolutionary and Functional Relationships among the Nontypeable
Haemophilus influenzae
HMW Family of Adhesins
Authors: Buscher Amy Z. , Burmeister Katie , Barenkamp Stephen J. , St. Geme Joseph W. 
Published: June 2004

ABSTRACT

Nontypeable
Haemophilus influenzae
(NTHi) is a common cause of localized respiratory tract disease and initiates infection by colonizing the nasopharynx. Approximately 75 to 80% of NTHi clinical isolates produce proteins that belong to the HMW family of adhesins, which are believed to facilitate colonization. The prototype HMW adhesins are designated HMW1 and HMW2 and were identified in NTHi strain 12. HMW1 and HMW2 are 71% identical and 80% similar overall, yet display differing cellular binding specificities. In the present study we set out to define more clearly the relationships between HMW1 and HMW2 and other members of the HMW family of adhesins. PCR analysis of 49 epidemiologically distinct isolates revealed that all strains possessing
hmw
genes as determined by Southern analysis contain two
hmw
loci in conserved, unlinked physical locations on the chromosome. Functional analysis of the HMW adhesins produced by three unrelated strains demonstrated that each isolate possesses one protein with HMW1-like adherence properties and another with HMW2-like adherence properties. These findings suggest that the
hmw1
and
hmw2
loci may have arisen via a gene duplication event in an ancestral strain. In addition, they support the hypothesis that the distinct binding specificities of HMW1 and HMW2 emerged early and have persisted over time, suggesting an ongoing selective advantage.
Heterologous Expression and Purification of Active Divercin V41, a Class IIa Bacteriocin Encoded by a Synthetic Gene in
Escherichia coli
Authors: Richard Christelle , Drider Djamel , Elmorjani Khalil , Marion Didier , Prévost Hervé 
Published: June 2004

ABSTRACT

Divercin V41, a class IIa bacteriocin with strong antilisterial activity, is produced by
Carnobacterium divergens
V41. To express a recombinant version of divercin V41, we constructed a synthetic gene that encodes the mature divercin V41 peptide and then overexpressed the gene in pET-32b by using the T7 RNA polymerase promoter in the
Escherichia coli
Origami (DE3)(pLysS) strain. The DvnRV41 peptide was expressed as a translational fusion protein with thioredoxin and accumulated in the cell cytoplasm in a soluble anti-
Listeria
active form. The fusion protein was then purified and cleaved to obtain pure, soluble, folded DvnRV41 (462 μg per 20 ml of culture). This paper describes the first design of a synthetic bacteriocin gene and the first bacteriocin expressed in the
E. coli
cytoplasm.
Recombination in the Genome ofChlamydia trachomatisInvolving the Polymorphic Membrane Protein C Gene Relative toompAand Evidence for Horizontal Gene Transfer
Authors: Gomes João P. , Bruno William J. , Borrego Maria J. , Dean Deborah 
Published: June 2004

ABSTRACTGenome sequencing ofChlamydia trachomatisserovar D has identified polymorphic membrane proteins (Pmp) that are a newly recognized protein family unique to theChlamydiaceaefamily. Cumulative data suggest that these diverse proteins are expressed on the cell surface and might be immunologically important. We performed phylogenetic analyses and statistical modeling with 18 reference serovars and 1 genovariant ofC. trachomatisto examine the evolutionary characteristics and comparative genetics of PmpC andpmpC, the gene that encodes this protein. We also examined 12 recently isolated ocular and urogenital clinical samples, since reference serovars are laboratory adapted and may not represent strains that are presently responsible for human disease. Phylogenetic reconstructions revealed a clear distinction for disease groups, corresponding to levels of tissue specificity and virulence of the organism. Further, the most prevalent serovars, E, F, and Da, formed a distinct clade. According to the results of comparative genetic analyses, these three genital serovars contained two putative insertion sequence (IS)-like elements with 10- and 15-bp direct repeats, respectively, while all other genital serovars contained one IS-like element. Ocular trachoma serovars also contained both insertions. Previously, no IS-like elements have been identified forChlamydiaceae. Surprisingly, 7 (58%) of 12 clinical isolates revealedpmpCsequences that were identical to the sequences of other serovars, providing clear evidence for a high rate of whole-gene recombination. Recombination and the differential presence of IS-like elements among distinct disease and prevalence groups may contribute to genome plasticity, which may lead to adaptive changes in tissue tropism and pathogenesis over the course of the organism's evolution.
Group I Intron Homing inBacillusPhages SPO1 and SP82: a Gene Conversion Event Initiated by a Nicking Homing Endonuclease
Authors: Landthaler Markus , Lau Nelson C. , Shub David. A. 
Published: June 2004

ABSTRACTMany group I introns encode endonucleases that promote intron homing by initiating a double-stranded break-mediated homologous recombination event. In this work we describe intron homing inBacillus subtilisphages SPO1 and SP82. The introns encode the DNA endonucleases I-HmuI and I-HmuII, respectively, which belong to the H-N-H endonuclease family and possess nicking activity in vitro. Coinfections ofB. subtiliswith intron-minus and intron-plus phages indicate that I-HmuI and I-HmuII are required for homing of the SPO1 and SP82 introns, respectively. The homing process is a gene conversion event that does not require the majorB. subtilisrecombination pathways, suggesting that the necessary functions are provided by phage-encoded factors. Our results provide the first examples of H-N-H endonuclease-mediated intron homing and the first demonstration of intron homing initiated by a nicking endonuclease.
Variation in the Effectors of the Type III Secretion System among
Photorhabdus
Species as Revealed by Genomic Analysis
Authors: Brugirard-Ricaud Karine , Givaudan Alain , Parkhill Julian , Boemare Noel , Kunst Frank , Zumbihl Robert , Duchaud Eric 
Published: June 2004

ABSTRACT

Entomopathogenic bacteria of the genus
Photorhabdu
s harbor a type III secretion system. This system was probably acquired prior to the separation of the species within this genus. Furthermore, the core components of the secretion machinery are highly conserved but the predicted effectors differ between
Photorhabdus luminescens
and
P. asymbiotica
, two highly related species with different hosts.
Characterization of Tn
916
S, a Tn
916
-Like Element Containing the Tetracycline Resistance Determinant
tet
(S)
Authors: Lancaster Holli , Roberts Adam P. , Bedi Raman , Wilson Michael , Mullany Peter 
Published: June 2004

ABSTRACT

We have characterized a transferable tetracycline resistance (Tc
r
) element from a
Streptococcus intermedius
isolate. The gene responsible for this resistance was identified by PCR and Southern hybridization as
tet
(S). Furthermore, the genetic support for this determinant was shown to be a conjugative transposon closely related to Tn
916
. This element has been designated Tn
916
S.
ALGEBRAIC APPROACH TO THE 1/N EXPANSION IN QUANTUM FIELD THEORY
Authors: HOLLANDS STEFAN 
Published: June 2004

The 1/N expansion in quantum field theory is formulated within an algebraic framework. For a scalar field taking values in the N by N hermitian matrices, we rigorously construct the gauge invariant interacting quantum field operators in the sense of power series in 1/N and the 't Hooft coupling parameter as members of an abstract *-algebra. The key advantages of our algebraic formulation over the usual formulation of the 1/N expansion in terms of Green's functions are (i) that it is completely local so that infrared divergencies in massless theories are avoided on the algebraic level and (ii) that it admits a generalization to quantum field theories on globally hypberbolic Lorentzian curved spacetimes. We expect that our constructions are also applicable in models possessing local gauge invariance such as Yang–Mills theories. The 1/N expansion of the renormalization group flow is constructed on the algebraic level via a family of *-isomorphisms between the algebras of interacting field observables corresponding to different scales. We also consider k-parameter deformations of the interacting field algebras that arise from reducing the symmetry group of the model to a diagonal subgroup with k factors. These parameters smoothly interpolate between situations of different symmetry.
NEUTRINO SPECTRUM DISTORTION DUE TO OSCILLATIONS AND ITS BBN EFFECT
Authors: KIRILOVA DANIELA 
Published: June 2004

We study the distortion of electron neutrino energy spectrum due to oscillations with the sterile neutrino νe↔νs, for different initial populations of the sterile state δNs at the onset of oscillations. The influence of this spectrum distortion on Big Bang Nucleosynthesis is analyzed. Only the case of an initially empty sterile state was studied in previous publications. The primordial abundance of 4He is calculated for all possible δNs:0≤δNs≤1 in the model of oscillations, effective after electron neutrino decoupling, for which the spectrum distortion effects on the neutron–proton transitions are the strongest. It is found that the spectrum distortion effect may be dominant, not only in the case of small δNs, but also in the case of large initial population of νs. For example, in the resonant case it may play a considerable role even for very large δNs~0.8. Cosmological constraints on neutrino mixing for small δNs are discussed.
α+-thalassemia protects African children from severe malaria
Authors: Mockenhaupt Frank P. , Ehrhardt Stephan , Gellert Sabine , Otchwemah Rowland N. , Dietz Ekkehart , Anemana Sylvester D. , Bienzle Ulrich 
Published: June 2004

Abstract
The high frequency of α+-thalassemia in malaria-endemic regions may reflect natural selection due to protection from potentially fatal severe malaria. In Africa, bearing 90% of global malaria morbidity and mortality, this has not yet been observed. We tested this hypothesis in an unmatched case-control study among 301 Ghanaian children with severe malaria and 2107 controls (62% parasitemic). In control children, α+-thalassemia affected neither prevalence nor density of Plasmodium falciparum. However, heterozygous α+-thalassemia was observed in 32.6% of controls but in only 26.2% of cases (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.56-0.98). Protection against severe malaria was found to be pronounced comparing severe malaria patients with parasitemic controls (adjusted OR in children &lt; 5 years of age, 0.52; 95% CI, 0.34-0.78) and to wane with age. No protective effect was discernible for homozygous children. Our findings provide evidence for natural selection of α+-thalassemia in Africa due to protection from severe malaria.
Gastric Cancer Surgery: Morbidity and Mortality Results From a Prospective Randomized Controlled Trial Comparing D2 and Extended Para-Aortic Lymphadenectomy—Japan Clinical Oncology Group Study 9501
Authors: Sano Takeshi , Sasako Mitsuru , Yamamoto Seiichiro , Nashimoto Atsushi , Kurita Akira , Hiratsuka Masahiro , Tsujinaka Toshimasa , Kinoshita Taira , Arai Kuniyoshi , Yamamura Yoshitaka , Okajima Kunio 
Published: June 2004

Purpose Radical gastrectomy with regional lymphadenectomy is the only curative treatment option for gastric cancer. The extent of lymphadenectomy, however, is controversial. The two European randomized trials only reported an increase in operative morbidity and mortality, but failed to show survival benefit, in the D2 lymphadenectomy group. We conducted a randomized controlled trial to compare the Japanese standard D2 and D2 + para-aortic nodal dissection. Patients and Methods Only experienced surgeons in both procedures from 24 Japanese institutions participated in the study. Patients with potentially curable gastric adenocarcinoma (T2-subserosa, T3, or T4) who were surgically fit were intraoperatively randomized. Postoperative morbidity and hospital mortality were recorded prospectively in a fixed format and were compared between the two groups in this study. Results A total of 523 patients were randomized between July 1995 and April 2001. Postoperative complications were reported in 24.5% of all patients. Although the morbidity for the extended surgery group (28.1%) was slightly higher than the standard group (20.9%), there was no difference in the incidence of four major complications (anastomotic leak, pancreatic fistula, abdominal abscess, pneumonia) between the two groups. Hospital mortality was reported at 0.80%: one patient in each group died of operative complications, while one from each group died of rapid progressive cancer while inpatient. Conclusion Specialized surgeons could safely perform gastrectomy with D2 lymphadenectomy in patients with low operative risks. Para-aortic lymphadenectomy could be added without increasing major surgical complications in this setting.
Surgical Factors Influence Bladder Cancer Outcomes: A Cooperative Group Report
Authors: Herr Harry W. , Faulkner James R. , Grossman H. Barton , Natale Ronald B. , deVere White Ralph , Sarosdy Michael F. , Crawford E. David 
Published: June 2004

Purpose A randomized, cooperative group trial (Southwest Oncology Group 8710, Intergroup 0080) reported that neoadjuvant chemotherapy improved the survival of patients with locally advanced bladder cancer who were treated with radical cystectomy. We evaluated whether surgical factors from patients enrolled onto the study predicted bladder cancer outcomes. Patients and Methods Surgical and tumor factors were recorded from surgical and pathologic reports from 268 patients with muscle-invasive bladder cancer who received radical cystectomy. Cystectomies were performed by 106 surgeons in 109 institutions. Half of the patients received neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) chemotherapy. Variables were tested in univariate and multivariate analyses for associations with postcystectomy survival (PCS) and local recurrence (LR) in all patients receiving cystectomy. Results Five-year PCS and LR rates were 54% and 15%, respectively. A multivariate model adjusted for MVAC (P = .97), age (P = .03), pathologic stage (P = .0002), and node status (P = .04) showed that surgical variables associated with longer PCS were negative margins (v positive; hazard ratio [HR], 0.37; P = .0007), and ≥ 10 nodes removed (v < 10; HR, 0.51; P = .0001). These associations did not differ by treatment arms (P > .21 for all tests of interactions between treatment and surgical variables). Predictors of LR in a multivariate model adjusted for MVAC (P = .16), pathologic stage (P = .02), and node status (P = .37) were positive margins (v negative; odds ratio [OR], 11.2; P = .0001) and fewer than 10 nodes removed (v ≥ 10; OR, 5.1; P = .002). Conclusion Surgical factors influence bladder cancer outcomes after cystectomy, after adjustment for pathologic factors and neoadjuvant chemotherapy usage.
Prevalence of High C-Reactive Protein in Persons with Serum Lipid Concentrations within Recommended Values
Authors: Ajani Umed A , Ford Earl S , Mokdad Ali H 
Published: June 2004

Abstract
Background: C-Reactive protein (CRP) has been shown to be a strong predictor of coronary heart disease (CHD) and is being considered in cardiovascular disease risk assessment. The number of normolipidemic individuals who are eligible for evaluation of CRP in overall CHD risk assessment is not known.
Methods: We analyzed data from the National Health and Nutrition Examination Survey 1999–2000 and computed the prevalence of high CRP (&gt;3 mg/L) among normolipidemic adults. We also computed the prevalence among individuals free of CHD and diabetes. In addition, we examined the prevalence stratified by body mass index.
Results: The prevalence of high CRP among those with lipid concentrations within recommended values ranged from 28.8% to 35.3%, depending on the lipid fraction examined. Exclusion of individuals with CHD or diabetes and those with CRP concentrations &gt;10 mg/L reduced the prevalence range (23.1–27.1%). Prevalence increased with increasing body mass index.
Conclusions: In 2000, ∼12 million adults in the United States considered normolipidemic had high CRP concentrations. Additional studies to explore the role of CRP in cardiovascular disease risk assessment are needed.
Evaluation of Warfarin Initiation Regimens in Elderly Inpatients
Authors: O'Connell Mary Beth , Kowal Paul R. , Allivato Caren J. , Repka Tanya L. 
Published: June 2004

Study Objective. To compare initial warfarin doses of 5 mg or below and doses above 5 mg in hospitalized elderly.Design. Retrospective review of charts identified from computerized pharmacy records.Setting. County teaching hospital.Patients. Inpatients aged 65 years or older receiving at least three warfarin doses.Intervention. We measured the time to first international normalized ratio (INR) of 2.0 or greater, bleeding complications, number of warfarin doses held, and vitamin K use.Measurements and Main Results. The average initial low dose (33 patients) was 4.8 ± 0.8 mg and the average initial high dose (40 patients) was 9.0 ± 1.2 mg. The mean time to first INR of 2.0 or greater was similar, 3.4 and 3.0 days, respectively (p=0.38). The low‐dose group had fewer bleeds (7 vs 13, p=0.28) and doses held (11 vs 18 patients, p=0.27, 30 vs 50 doses). Four patients in each group received vitamin K (p=0.8). Forty‐four percent of patients with an INR of 4 or above and 48% of patients who had a dose held were on a long‐term drug or had a new drug added that could cause a major drug interaction with warfarin.Conclusion. In this pilot study, hospitalized elderly who received a low versus high initial dose of warfarin achieved therapeutic INRs in a similar time and had lower but not significantly different safety outcomes.
A robust air‐gap flux estimation for speed sensorless vector control of double‐star induction machine
Authors: Mimouni M.F. , Dhifaoui R. 
Published: June 2004

AbstractThe paper presents a new direct field‐oriented control (DFOC) for double‐star induction machine (DSIM) drives using the stator currents. First, we propose a new algorithm to estimate air‐gap flux for speed sensorless air‐gap flux orientation control. Compared to the previous DFOC schemes the new one is independent from any motor parameter variation, specially on the stator resistance. Then, the DFOC is associated with a low pass filter (LPF) to solve the dc drift problems caused by the pure integration of air‐gap flux. In the present paper, the rotor resistance is estimated by an algorithm using Lyapunov theory. Good results have been obtained in the benchmark simulations. Copyright © 2004 John Wiley & Sons, Ltd.
Towards a Transparent, Highly Conductive Poly(3,4‐ethylenedioxythiophene)
Authors: Ha Y.‐H. , Nikolov N. , Pollack S. K. , Mastrangelo J. , Martin B. D. , Shashidhar R. 
Published: June 2004

AbstractA detailed investigation of the processing parameters influencing the oxidative polymerization of 3,4‐ethylenedioxythiophene (EDOT) and a methanol‐substituted derivative (EDOT–CH2OH) was performed with the goal of maximizing the conductivity of the polymer. We show that the conductivity can be significantly enhanced by varying the monomer, oxidant (iron(III) p‐toluenesulfonate (Fe(OTs)3)), weak base (imidazole (Im)), solvent (various alcohols), and solution concentrations. The effect of each variable on the final materials properties is investigated, and the parameters have been optimized to achieve conductivities as high as 900 S cm–1. Surface resistance below 150 Ω/□ for 80–90 nm thick films with visible‐spectrum transparency exceeding 80 % is achieved. The combination of these properties makes the films highly suitable for numerous device applications.
Electric‐Field‐Directed Growth of Gold Nanorods in Aqueous Surfactant Solutions
Authors: Pérez‐Juste J. , Liz‐Marzán L. M. , Carnie S. , Chan D. Y. C. , Mulvaney P. 
Published: June 2004

AbstractThe factors affecting the nucleation and growth of gold nanorods, (Jana et al., Adv. Mater. 2001, 13, 1389) have been investigated. It is shown that the size and aspect ratio can be controlled through the use of different sized seed particles. The length of the rods can be tuned from 25–170 nm, while the width remains almost constant at 22–25 nm. The formation of rods requires the presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB). Lower temperature favors rod formation, although this reduces CTAB solubility. The addition of chloride ions or the use of dodecyltrimethylammonium bromide (DTAB) leads to shorter‐aspect rods. AuIII and AuI are shown to be quantitatively bound to the CTAB micelles. We propose an electrochemical mechanism for rod formation, whereby the flux of AuI bound to cationic micelles to the seed surface is maximized at points of highest curvature, where the electrical double layer gradient is highest. Initial numerical solutions to the electric potential and field around an ellipsoid in a 1:1 electrolyte are provided, which indicate that the field at the particle tip scales linearly with the aspect ratio. Mean free passage times for ions are found to be shortest at the tips. The results provide a general explanation for the formation of non‐equilibrium crystal habits and a mechanism for controlling crystal growth.
Surface Molecularly Imprinted Polymer Core–Shell Particles
Authors: Carter S. R. , Rimmer S. 
Published: June 2004

AbstractCore–shell molecularly imprinted polymers (CS‐MIPs) have been prepared by aqueous emulsion polymerization using water‐soluble template molecules. An amphiphilic binding monomer, oleyl phenyl hydrogen phosphate and ethylene glycol dimethacrylate were used in the formation of highly crosslinked surfaces around divinyl benzene crosslinked polystyrene core colloids. Evidence was obtained by transmission electron microscopy (TEM) for a change in surface morphology when the polymer shell was formed in the presence of a template. The caffeine‐imprinted polymers were shown to bind caffeine in preference to theophylline from an equimolar mixture of the compounds in aqueous solution at pH 7.0, whilst concentration–binding (Scatchard) curves revealed the presence of two populations of binding sites in aqueous phosphate buffer at pH 8.0 for caffeine and theophylline. Similar studies were also carried out for (S)‐propranolol and (S)‐atenolol at pH 5.5, which also revealed the presence of two populations of binding sites for core–shell particles imprinted with these compounds. (S)‐Propranolol was selectively removed from a solution of (S)‐propranolol and (S)‐atenolol by both of the CS‐MIPs, whereas the non‐imprinted particle showed no selectivity for either component.
Well‐Aligned ZnO Nanowire Arrays Fabricated on Silicon Substrates
Authors: Geng C. , Jiang Y. , Yao Y. , Meng X. , Zapien J. A. , Lee C. S. , Lifshitz Y. , Lee S. T. 
Published: June 2004

AbstractArrays of well‐aligned single‐crystal zinc oxide (ZnO) nanowires of uniform diameter and length have been synthesized on a (100) silicon substrate via a simple horizontal double‐tube system using chemical vapor transport and condensation method. X‐ray diffraction and transmission electron microscopy (TEM) characterizations showed that the as‐grown nanowires had the single‐crystal hexagonal wurtzite structure with detectable defects and a <0002> growth direction. Raman spectra revealed phonon confinement effect when compared with those of ZnO bulk powder, nanoribbons, and nanoparticles. Photoluminescence exhibited strong ultraviolet emission at 3.29 eV under 355 nm excitation and green emission at 2.21 eV under 514.5 nm excitation. No catalyst particles were found at the tip of the nanowires, suggesting that the growth mechanism followed a self‐catalyzed and saturated vapor–liquid–solid (VLS) model. Self‐alignment of nanowires was attributed to the local balance and steady state of vapor flow at the substrate. The growth technique would be of particular interest for direct integration in the current silicon‐technology‐based optoelectronic devices.