bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association of parental smoking behaviors and absences in school‐age children: Implications for the nurse practitioner
Authors: Birney Margaret Hamilton , Hardie Thomas L. , Crowley Evelyn M. 
Published: May 2006

AbstractPurpose:To examine the association between reported absences and parental smoking in school‐age children, aged 6–17, and to specifically explore the impact of maternal smoking on the health and attendance of school‐age children.Data sources:The sample of 7488 parent–child dyads was randomly selected from the 2002 National Health Interview Survey, a multipurpose cross‐sectional household interview survey conducted by the Centers for Disease Control and Prevention. The parent sample included 2673 men and 4375 women. Children’s ages ranged from 6 to 17 with a mean of 11.7 years.Conclusions:Maternal, but not paternal, present and past smoking behavior significantly impacts the child’s wellness and school attendance. The reasons for this disparity are unclear but may relate to synergistic effects of pre‐ and postnatal nicotine exposure, the traditional role of mother as caregiver, or specific smoking habits that increase environmental tobacco exposure.Implications for practice:Assessment and educational strategies for families regarding the hazards of childhood exposure to environmental tobacco smoke are indicated. Specific implications for the role of the nurse practitioner across diverse specialties are addressed with emphasis on the need for development of gender, age, and culturally sensitive smoking cessation programs and support networks.
Synergistic Effects in Mixed
Escherichia coli
Biofilms: Conjugative Plasmid Transfer Drives Biofilm Expansion
Authors: Reisner Andreas , Höller Brigitte M. , Molin Søren , Zechner Ellen L. 
Published: May 2006

ABSTRACT

Bacterial biofilms, often composed of multiple species and genetically distinct strains, develop under complex influences of cell-cell interactions. Although detailed knowledge about the mechanisms underlying formation of single-species laboratory biofilms has emerged, little is known about the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of
Escherichia coli
were monitored. Synergistic induction of biofilm formation resulting from the cocultivation of 403 undomesticated
E. coli
strains with a characterized
E. coli
K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of
E. coli
isolates (
n
= 56) exhibiting the strongest effects was most often linked to conjugative transmission of natural plasmids carried by the
E. coli
isolates (70%). Thus, the capacity of an isolate to promote the biofilm through cocultivation was (i) transferable to the K-12 strain, (ii) was linked with the acquisition of conjugation genes present initially in the isolate, and (iii) was inhibited through the presence in the cocultured K-12 strain of a related conjugative plasmid, presumably due to surface exclusion functions. Synergistic effects of cocultivation of pairs of natural isolates were also observed, demonstrating that biofilm promotion in this system is not dependent on the laboratory strain and that the described model system could provide relevant insights on mechanisms of biofilm development in natural
E. coli
populations.
Flavonoid-Inducible Modifications to Rhamnan O Antigens Are Necessary for
Rhizobium
sp. Strain NGR234-Legume Symbioses
Authors: Broughton W. J. , Hanin M. , Relić B. , Kopciñska J. , Golinowski W. , Şimşek Ş. , Ojanen-Reuhs T. , Reuhs B. , Marie C. , Kobayashi H. , Bordogna B. , Le Quéré A. , Jabbouri S. , Fellay R. , Perret X. , Deakin W. J. 
Published: May 2006

ABSTRACT

Rhizobium
sp. strain NGR234 produces a flavonoid-inducible rhamnose-rich lipopolysaccharide (LPS) that is important for the nodulation of legumes. Many of the genes encoding the rhamnan part of the molecule lie between 87° and 110° of pNGR234
a
, the symbiotic plasmid of NGR234. Computational methods suggest that 5 of the 12 open reading frames (ORFs) within this arc are involved in synthesis (and subsequent polymerization) of
l
-rhamnose. Two others probably play roles in the transport of carbohydrates. To evaluate the function of these ORFs, we mutated a number of them and tested the ability of the mutants to nodulate a variety of legumes. At the same time, changes in the production of surface polysaccharides (particularly the rhamnan O antigen) were examined. Deletion of
rmlB
to
wbgA
and mutation in
fixF
abolished rhamnan synthesis. Mutation of y4gM (a member of the ATP-binding cassette transporter family) did not abolish production of the rhamnose-rich LPS but, unexpectedly, the mutant displayed a symbiotic phenotype very similar to that of strains unable to produce the rhamnan O antigen (NGRΔ
rmlB-wbgA
and NGRΩ
fixF
). At least two flavonoid-inducible regulatory pathways are involved in synthesis of the rhamnan O antigen. Mutation of either pathway reduces rhamnan production. Coordination of rhamnan synthesis with rhizobial release from infection threads is thus part of the symbiotic interaction.
Étude quantitative des réactions d'ozonolyse. V. Sur le clivage de l'ozonide primaire des styrènes substitués dans le noyau
Authors: Fliszâr S. , Renard J. 
Published: May 2006

For the ozonization of ring-substituted styrènes, the proportions of the two ways of cleavage yielding (a) [Formula: see text]and (b) [Formula: see text]are related by the equation [Formula: see text] to Hammett's σ and ρ constants (x = proportion of cleavage following route a; ▵▵Go≠ (0.22 kcal/mole at 25°C) = Gibbs activation energy difference between assumed transition states of the primary styrene ozonide). The interpretation in terms of transition states concludes that the zwitterion is preferentially formed at the carbon atom with the highest electron density.
The influence of pH and inhibitors on the kinetics of enzyme reactions involving two intermediates
Authors: Kaplan Harvey , Laidler Keith J. 
Published: May 2006

General steady-state equations are worked out for enzyme reactions which occur according to the scheme[Formula: see text]Equations showing the pH dependence of the kinetic parameters are developed in a form which distinguishes between essential and nonessential ionizing groups. The pK dependence of[Formula: see text], the second-order constant extrapolated to zero substrate constant, gives pK values for groups which ionize on the free enzyme, but reveals such a pK only if the corresponding group is also involved in the breakdown of the Michaelis complex. General steady-state equations are also developed for the case in which an inhibitor can combine with the free enzyme, the enzyme–substrate complex, and also a second intermediate (e.g. an acyl enzyme). The equations are given in a form that is convenient for analyzing the experimental results, and a number of special cases are considered. It is shown how the type of inhibition depends not only on the nature of the inhibitor but also on that of the substrate, an important factor being the rate-determining step of the reaction. Examples of the various kinds of behavior are given.
The γ-radiolysis of cysteine in deaerated 1 N HClO4 solutions
Authors: Wilkening Verna Gaye , Lal Manohar , Arends Meta , Armstrong David A. 
Published: May 2006

The G values for the formation of H2, H2S, alanine (CyH), and cystine ((CyS)2) in the 60Co γ-radiolysis of 10−3 and 10−2 M solutions of cysteine (CySH) in 1 N perchloric acid at 23 °C have been determined. They are quantitatively consistent with the following reaction mechanism. [Formula: see text]The yields of H2 and H2S have also been measured at 1 ± 1°C. If H atoms are assumed to be the only reducing species in 1 N perchloric acid, k1/k2 was found to be 3.5 at 23 °C and 8 at 1 °C.
Concurrent ion–molecule reactions. III. Reactions in mixtures of HCl and HCN with D2 and CD4
Authors: Harrison A. G. , Thynne J. C. J. 
Published: May 2006

The concurrent ion–molecule reactions in mixtures of HCl and HCN with D2 and CD4 have been studied by the ratio plot method. The following reactions have been detected in mixtures with HCN and their cross sections determined at 10.5 V cm−1 repeller field strength. [Formula: see text]In mixtures of D2 and CD4 with HCl the following reactions have been detected and cross sections determined. [Formula: see text]Rate constants for the self-reactions in HCN and HCl have been measured both at 10.5 V cm1 repeller field and at thermal ion energies.
Substitution of acyclic sugar acetals. Is the acid-catalyzed substitution of erythro and threo l,2,3,4,5-penta-O-acetyl-l-arabinose S-ethyl monothioacetals anchimerically assisted?
Authors: Painter Edgar Page , Kurihara Norman H. 
Published: May 2006

The rate constants for the inversion and for the 14C-acetoxy exchange of the diastereomeric 1,2,3,4,5-penta-O-acetyl S-ethyl monothioacetals show that the substitution is not anchimerically assisted by the C2-acetoxy group. The substitution of acyclic poly-O-acetyl sugar monoacetals is best explained by the formation of the acyclic intermediate [Formula: see text] (X = S or O) in the rate-determining step.
Electrochemical reactions at PbO2 electrodes. Part I. The passivation of β-PbO2 in perchloric acid
Authors: Hampson N. A. , Jones P. C. , Phillips R. F. 
Published: May 2006

The cathodic passivation of β-PbO2 electrodes in electrolytes based on perchlorate ion has been studied as a function of current density and electrolyte composition.Before passivation the electrode remains free of films based on Pb(II).Passivation results are correlated in the form of a modified diffusion equation incorporating two parameters kp and i1. [Formula: see text]
Addition of alkoxide ions to alkenes. The HR– scale
Authors: Kroeger D. J. , Stewart Ross 
Published: May 2006

By using α-cyanostilbenes as Lewis acids, Lewis acidity scales have been established in ethanolic and methanolic dimethyl sulfoxide containing the appropriate 0.01 M sodium alkoxide and in the system sodium methoxide – methanol. This scale, designated [Formula: see text], describes the ability of the solvent to add an alkoxide ion to an alkene. The [Formula: see text] values range from 11.73 in methanol to 21.74 in 93.27 mole % dimethyl sulfoxide in ethanol.The most acidic indicator used to establish the scale was α-cyano-2,4-dinitrostilbene, with a pKA of 12.73 in dimethyl sulfoxide – methanol. The least acidic was α-cyano-3-trifluoro-methylstilbene, with a pKA of 21.98 in dimethyl sulfoxide – ethanol.The increase in the system's ability to add alkoxide ion to the cyanostilbenes as the dimethyl sulfoxide concentration rises is ascribed chiefly to its effect on the activity of the alkoxide ion. The functions H− and [Formula: see text], unlike their analogues in acid systems (H0 and Hr), do not diverge greatly as the concentration of the hydroxylic solvent component is decreased.
Conformational analysis of trans-1,4-dihalocyclohexanes
Authors: Wood Gordon , Woo E. P. 
Published: May 2006

The conformational equilibria of trans-1,4-dibromo- (I), trans-1,4-dichloro- (II), and trans-1,4-bromochloro-cyclohexane (III) were determined by integration of the separate axial and equatorial proton signals at low temperature. The [Formula: see text] values for compounds I, II, and III were found to be approximately 200 cal/mole.
Amino acid radicals produced chemically in aqueous solutions. Electron spin resonance spectra and relation to radiolysis products
Authors: Armstrong W. A. , Humphreys W. G. 
Published: May 2006

Amino acid radicals were generated by the reaction of titanium trichloride with hydrogen peroxide in the presence of an amino acid, and were identified by electron spin resonance spectroscopy. An amino acid analyzer was used to show that the products of this reaction were the same as those of the corresponding γ-irradiated, oxygenated aqueous amino acid solution. Cysteine, cystine, and homocystine gave identical spectra which were attributed to [Formula: see text]·radicals, whereas penicillamine gave [Formula: see text]·radicals. Most other amino acid radicals were formed by the abstraction of a hydrogen atom from the C2 position (numbered from the amino group). This was true for dl-α-alanine, β-alanine, taurine, dl-aspartic acid, γ-aminoisobutyric acid, dl-serine, and dl-valine, although with valine a lower concentration of the radical resulting from the removal of a hydrogen atom from C3 was also observed. Abstraction from the C3 position also occurred with dl-threonine. These facts are consistent with the view that the strong negative inductive effect of the NH3+ group deactivates the neighboring C—H bond towards attack by the electrophilic hydroxyl radical. Glycine formed one radical by the loss of a hydrogen atom from the C1 position, and a second by deamination.
Decomposition pressures and enthalpies of formation of some transition metal diarsenides and diselenides
Authors: Murray J. J. , Heyding R. D. 
Published: May 2006

The phase relations for the systems Pt/As, Os/As, Os/Se, and Ru/Se have been examined in the range 850–1 250 °K. Using the torsion effusion method, the decomposition pressures of PtAs2, OsAs2, OsSe2, and RuSe2 have been measured as a function of temperature. The apparatus and procedures were verified by measuring the vapor pressure of liquid silver. Equilibrium pressures were obtained for PtAs2 and RuSe2. OsAs2 exhibited an orifice area dependent nonequilibrium behavior and OsSe2 exhibited a time dependent nonequilibrium behavior. Equilibrium pressures were estimated in these latter two cases. Total equilibrium decomposition pressures (Pt), i.e. the pressure of arsenic or selenium vapors in equilibrium with each phase, are best described by the equations: [Formula: see text]Literature data on the equilibria between the various molecular species in selenium and arsenic vapor indicate that at these pressures and temperatures the vapor in equilibrium with the selenides is essentially pure Se2, but the vapor over the arsenides is a mixture of As2 and As4.The heats and entropies of decomposition of PtAs2, OsAs2, OsSe2, and RuSe2 have been calculated from the decomposition pressure data. The standard heats of formation at 298 °K are −42.0 ± 3.5, −18.5 ± 2.0, −32.5 ± 5.0, and −42.9 ± 3.5 kcal/mole, respectively. Heats of formation of MnSe2, CoSe2, NiSe2, and RhSe2 have been estimated using the heats of formation of OsSe2 and RuSe2, the Born–Mayer equation, and the Born–Haber cycle. These are −96 ± 8, −70 ± 8, −41 ± 8, and −12 ± 12 kcal/mole, respectively.
Reaction of active nitrogen with oxygen
Authors: Vlastaras A. S. , Winkler C. A. 
Published: May 2006

The maximum yields of oxygen atoms, estimated at different levels in a long-tube reactor by gas-phase "titration" with NO2, were equal for the reactions of active nitrogen with NO and O2. In this reactor, the maximum oxygen-atom production from the oxygen reaction, determined by the amount of N2O3 produced with excess NO2, was found to correspond to the NO "titration" value for the active nitrogen and not to the maximum amount of HCN produced in the active nitrogen – ethylene reaction. A second-order rate constant, [Formula: see text] [Formula: see text]was obtained for the active nitrogen – oxygen reaction.Experiments in a short reactor showed that the validity of the analytical method based on the trapping of N2O3 depended upon adequate reaction time for the NO + NO2 reaction to occur.
The infrared spectra of theobromine salts
Authors: Cook Denys , Regnier Zephyr R. 
Published: May 2006

From the infrared spectra of theobromine salts it is concluded that the salts are probably arranged in hydrogen-bonded centrosymmetric pairs involving [Formula: see text] interactions. [Formula: see text] anion− hydrogen bonds are formed by protonation of the free nitrogen atom (N9) in the imidazole ring. Infrared absorption bands arising from the former hydrogen bond constantly appear near 3 000 cm−1, whereas those from the latter shift from 2 580 to 3 300 cm−1, depending on the anion. In-plane NH and N+H deformation modes give bands near 1 485 and 1 160 cm−1, respectively. Out-of-plane NH modes have been located, but precise assignments are not possible.The assignments for some other bands which show deuteration shifts are detailed, and the carbonyl stretching vibrations which increase in frequency on protonation of the free base are identified.
Ion–molecule reactions in gaseous methyl amine
Authors: Jones E. G. , Harrison A. G. 
Published: May 2006

The ion–molecule reactions in gaseous methyl amine have been studied. The following reactions have been identified and their rate coefficients (all in cm3 molecule−1 s−1 units) determined for ions of 3.4 eV ion exit energy. [Formula: see text]Reactions [a] and [c] were also studied at thermal ion energies and little variation of the rate coefficients with ion energy was found in contrast with theoretical predictions.
How artificial intelligence tools can be used to assess individual patient risk in cardiovascular disease: problems with the current methods
Authors: Grossi Enzo 
Published: May 2006

Abstract

Background
In recent years a number of algorithms for cardiovascular risk assessment has been proposed to the medical community. These algorithms consider a number of variables and express their results as the percentage risk of developing a major fatal or non-fatal cardiovascular event in the following 10 to 20 years

Discussion
The author has identified three major pitfalls of these algorithms, linked to the limitation of the classical statistical approach in dealing with this kind of non linear and complex information. The pitfalls are the inability to capture the disease complexity, the inability to capture process dynamics, and the wide confidence interval of individual risk assessment.
Artificial Intelligence tools can provide potential advantage in trying to overcome these limitations. The theoretical background and some application examples related to artificial neural networks and fuzzy logic have been reviewed and discussed.

Summary
The use of predictive algorithms to assess individual absolute risk of cardiovascular future events is currently hampered by methodological and mathematical flaws. The use of newer approaches, such as fuzzy logic and artificial neural networks, linked to artificial intelligence, seems to better address both the challenge of increasing complexity resulting from a correlation between predisposing factors, data on the occurrence of cardiovascular events, and the prediction of future events on an individual level.
Intra-cluster correlation coefficients in adults with diabetes in primary care practices: the Vermont Diabetes Information System field survey
Authors: Littenberg Benjamin , MacLean Charles D 
Published: May 2006

Abstract

Background
Proper estimation of sample size requirements for cluster-based studies requires estimates of the intra-cluster correlation coefficient (ICC) for the variables of interest.

Methods
We calculated the ICC for 112 variables measured as part of the Vermont Diabetes Information System, a cluster-randomized study of adults with diabetes from 73 primary care practices (the clusters) in Vermont and surrounding areas.

Results
ICCs varied widely around a median value of 0.0185 (Inter-quartile range: 0.006, 0.037). Some characteristics (such as the proportion having a recent creatinine measurement) were highly associated with the practice (ICC = 0.288), while others (prevalence of some comorbidities and complications and certain aspects of quality of life) varied much more across patients with only small correlation within practices (ICC<0.001).

Conclusion
The ICC values reported here may be useful in designing future studies that use clustered sampling from primary care practices.
Estimating and projecting HIV prevalence and AIDS deaths in Tanzania using antenatal surveillance data
Authors: Somi Geofrey R , Matee Mecky IN , Swai Roland O , Lyamuya Eligius F , Killewo Japhet , Kwesigabo Gideon , Tulli Tuhuma , Kabalimu Titus K , Ng'ang'a Lucy , Isingo Raphael , Ndayongeje Joel 
Published: May 2006

Abstract

Background
The Estimations and Projections Package (EPP 2005) for HIV/AIDS estimates and projects HIV prevalence, number of people living with HIV and new HIV infections and AIDS cases using antenatal clinic (ANC) surveillance data. The prevalence projection produced by EPP can be transferred to SPECTRUM, a demographic projectionmodel, to calculate the number of AIDS deaths. This paper presents estimates and projections of HIV prevalence, new cases of HIV infections and AIDS deaths in Tanzania between 2001 and 2010 using the EPP 2005 and SPECTRUM soft-wares on ANC data.

Methods
For this study we used; the 1985 – 2004 ANC data set, the 2005 UN population estimates for urban and rural adults, which is based on the 2002 population census, and results of the 2003 Tanzania HIV Indicator Survey. The ANC surveillance sites were categorized into urban and rural areas on the basis of the standard national definitions of urban and rural areas, which led to 40 urban and 35 rural clinic sites. The rural and urban epidemics were run independently by fitting the model to all data and on level fits.

Results
The national HIV prevalence increased from 0% in 1981 to a peak of 8.1% in 1995, and gradually decreased to 6.5% in 2004 which stabilized until 2010. The urban HIV epidemic increased from 0% in 1981 peaking at 12.6% in 1992 and leveled to between 10.9% and 11.8% from 2003 to 2010. The rural epidemic peaked in 1995 at 7.0% and gradually declined to 5.2% in 2004, and then stabilized at between 5.1% and 5.3% from 2005 to 2010. New infections are projected to rise steadily, resulting in 250,000 new cases in 2010. Deaths due to AIDS started in 1985 and rose steadily to reach 120,000 deaths in 2010, with more females dying than men.

Conclusion
The fact that the number of new infections is projected to increase steadily to reach 250,000 per year in 2010 calls for more concerted efforts to combat the spread of HIV infection particularly in the rural areas where the infrastructure needed for prevention programmes such as counseling and testing, condom accessibility and AIDS information is less developed.
Self-reported drug utilization, health, and lifestyle factors among 70–74 year old community dwelling individuals in Western Norway. The Hordaland Health Study (HUSK)
Authors: Brekke Mette , Hunskaar Steinar , Straand Jørund 
Published: May 2006

Abstract

Background
To examine the level and patterns of self-reported medication use (prescription and non-prescription drugs) among 70–74 year old individuals living in the community, and to explore self-reported indications for use, and factors possibly predictive of drug use.

Methods
A health survey carried out in 1997–99 in the county of Hordaland (Western Norway) in the setting of a population study. A self-administered questionnaire was mailed to 4338 persons born in 1925–27, and a health check-up was offered. Drug use the previous day was reported (point prevalence). 3341 (77.0%) persons who responded, comprise the material for the analyses.

Results
Between one third (males) and one quarter (females) did not take any drug the previous day. Mean number of drugs among users was 2.8 (men and women). 32% used three or more drugs and 11.5% five or more. Hypertension and other cardiovascular problems were by far the most common reasons for drug use, followed by respiratory, musculoskeletal and mental health problems. Self-reported poor health, a high Body Mass Index (BMI), and being an ex-smoker (but not currently a smoker) correlated with increasing number of drugs taken.

Conclusion
Among 70–74-year old individuals living in the community no use of medication was more common than major polypharmacy (5+ drugs). Persons who had fallen ill and were put on regular medication, probably tended to quit smoking, while those who remained healthy, continued to smoke.