bluuebunny/crossref_metadata_2025_split huggingface dataset:
New definitions of extended‐spectrum β‐lactamase conferring worldwide emerging antibiotic resistance
Authors: Lee Jung Hun , Bae Il Kwon , Hee Lee Sang 
Published: June 2010

AbstractAlthough there is no consensus of the precise definition of ESBL, three kinds of ESBL definitions have been proposed. First, the classical definition includes variants derived from TEM‐1, TEM‐2, or SHV‐1; K1 (KOXY) of Klebsiella oxytoca. Second, the broadened definition has stretched the classical definition of ESBL to include: (1) β‐lactamases (CTX‐M‐ESBLs, GES‐ESBLs, and VEB‐ESBLs), with spectra similar to those of TEM and SHV variants (designated as TEM‐ and SHV‐ESBLs, respectively) but derived from other sources; (2) TEM and SHV variants with borderline ESBL activity; e.g., TEM‐12; and (3) various β‐lactamases conferring wider resistance than their parent types but not meeting the definition for group 2be; e.g., OXA‐types (OXA‐ESBLs) and mutant AmpC‐types (AmpC‐ESBLs), with increased activity against oxyimino‐cephalosporins and with resistance to clavulanic acid. Third, the all‐inclusive definition includes: (1) ESBLA (named for class A ESBLs); (2) ESBLM (miscellaneous ESBLs), which has been subdivided into ESBLM‐C (class C; plasmid‐mediated AmpC) and ESBLM‐D (class D); and (3) ESBLCARBA (ESBLs with hydrolytic activity against carbapenems), which has been subdivided into ESBLCARBA‐A (class A carbapenemases), ESBLCARBA‐B (class B carbapenemases), and ESBLCARBA‐D (class D carbapenemases). The consensus view about the ESBL definition is that the classical ESBL definition must be expanded to class A non‐TEM‐ and non‐SHV‐ESBLs (CTX‐M‐, GES‐, VEB‐ESBLs, etc.). However, these three definitions evoke rational debate on the question “Which would be included in the category of ESBLs among AmpC‐ESBLs, OXA‐ESBLs, and/or carbapenemases?” Therefore, there is a great need for consensus in the precise definition of ESBL.  © 2010 Wiley Periodicals, Inc. Med Res Rev 32:216‐232, 2012
Potential of carbohydrate‐binding agents as therapeutics against enveloped viruses
Authors: François K. O. , Balzarini J. 
Published: June 2010

AbstractTwenty‐seven years after the discovery of HIV as the cause of AIDS more than 25 drugs directed against four different viral targets (i.e. reverse transcriptase, protease, integrase, envelope gp41) and one cellular target (i.e. CCR5 co‐receptor) are available for treatment. However, the search for an efficient vaccine is still ongoing. One of the main problems is the presence of a continuously evolving dense carbohydrate shield, consisting of N‐linked glycans that surrounds the virion and protects it against efficient recognition and persistent neutralization by the immune system. However, several lectins from the innate immune system specifically bind to these glycans in an attempt to process the virus antigens to provoke an immune response. Across a wide variety of different species in nature lectins can be found that can interact with the glycosylated envelope of HIV‐1 and can block the infection of susceptible cells by the virus. In this review, we will give an overview of the lectins from non‐mammalian origin that are endowed with antiviral properties and discuss the complex interactions between lectins of the innate immune system and HIV‐1. Also, attention will be given to different carbohydrate‐related modalities that can be exploited for antiviral chemotherapy. © 2010 Wiley Periodicals, Inc. Med Res Rev
5‐fluorouracil metabolite patterns in viable and necrotic tumor areas of murine colon carcinoma determined by 19F NMR spectroscopy
Authors: Kamm Yvonne J. L. , Heerschap Arend , Rosenbusch Gert , Rietjens Ivonne M. C. M. , Vervoort Jacques , Wagener D. J. Theo 
Published: June 2010

AbstractHigh‐resolution 19F NMR spectroscopy at 9.4 T was used to study the difference in the metabolite pattern of 5‐fluorouracil (5‐FU) between viable and necrotic tissues of C38 murine colon tumors grown in C57BI/6 mice. Studies were performed on perchloric acid extracts of these tumor fractions after 5‐FU treatment. The 19F nuclear magnetic resonance spectra exhibited resonances representing 5‐FU, the catabolites α‐fluoro‐β‐ureidopropionic acid and α‐fluoro‐β‐alanine, as well as several fluoronucleotide anabolites. The absolute concentrations of anabolites and catabolites and the anabolite‐to‐catabolite ratio were significantly lower in the necrotic fraction than in the viable tumor fraction 50 min after administration of 5‐FU, whereas the absolute concentration of 5‐FU was the same. Therefore, in 5‐FU metabolism studies with NMR spectroscopy, it is important to consider the necrotic contribution to the tumor volume.
Intracellular bimodal nanoparticles based on quantum dots for high‐field MRI at 21.1 T
Authors: Rosenberg Jens T. , Kogot Joshua M. , Lovingood Derek D. , Strouse Geoffrey F. , Grant Samuel C. 
Published: June 2010

AbstractMultimodal, biocompatible contrast agents for high magnetic field applications represent a new class of nanomaterials with significant potential for tracking of fluorescence and MR in vitro and vivo. Optimized for high‐field MR applications—including biomedical imaging at 21.1 T, the highest magnetic field available for MRI—these nanoparticles capitalize on the improved performance of chelated Dy3+ with increasing magnetic field coupled to a noncytotoxic Indium Phosphide/Zinc Sulfide (InP/ZnS) quantum dot that provides fluorescence detection, MR responsiveness, and payload delivery. By surface modifying the quantum dot with a cell‐penetrating peptide sequence coupled to an MR contrast agent, the bimodal nanomaterial functions as a self‐transfecting high‐field MR/optical contrast agent for nonspecific intracellular labeling. Fluorescent images confirm sequestration in perinuclear vesicles of labeled cells, with no apparent cytotoxicity. These techniques can be extended to impart cell selectivity or act as a delivery vehicle for genetic or pharmaceutical interventions. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
The history of the second‐trimester sonographic markers for detecting fetal Down syndrome, and their current role in obstetric practice
Authors: Benacerraf Beryl R. 
Published: June 2010

AbstractThis review summarizes the development, history and use of second‐trimester sonographic markers for the detection of fetal Down syndrome over three decades. Starting with the nuchal fold thickening in 1985 and culminating in the genetic sonogram in the 1990s. The combination of second‐trimester serum screening with the ultrasound markers improved the detection rate of affected fetuses but also allowed patients to decrease their risk of carrying a fetus with Down syndrome if the genetic sonogram was normal. More recently the role of the genetic sonogram and its markers have changed with the wide spread use of first‐trimester screening. This prior screening ultimately decreases the prevalence of fetal Down syndrome in the second trimester to less than 85% of what it was in the first‐trimester as most fetuses with Down syndrome are now identified early. Current interpretation of the second‐trimester Down syndrome markers must be based on the result of the first trimester and combined screening to achieve the most accurate risk estimate of an affected fetus. Copyright © 2010 John Wiley & Sons, Ltd.
Fetal cardiac scanning today
Authors: Allan Lindsey 
Published: June 2010

AbstractThe ability to examine the structure of the fetal heart in real‐time started over 30 years ago now. The field has seen very great advances since then, both in terms of technical improvements in ultrasound equipment and in dissemination of operator skills. A great deal has been learnt about normal cardiac function in the human fetus throughout gestation and how it is affected by pathologies of pregnancy. There is increasing recognition of abnormal heart structure during routine obstetric scanning, allowing referral for specialist diagnosis and counselling. It is now possible to make accurate diagnosis of cardiac malformations as early as 12 weeks of gestation. Early diagnosis of a major cardiac malformation in the fetus can provide the parents with a comprehensive prognosis, enabling them to make the most informed choice about the management of the pregnancy. Copyright © 2010 John Wiley & Sons, Ltd.
The 18‐week fetal examination and detection of anomalies
Authors: Eik‐Nes Sturla H. 
Published: June 2010

AbstractFrom its beginning in the fifties the use of ultrasound in gynaecology and obstetrics has expanded extensively. Ultrasound technology has taken us from a time when the mother was our prime focus to the present where it is the unborn baby. Ultrasound assessments may have significant consequences for pregnancy care by optimizing the time, the mode and the location of the delivery as well as preparing the postnatal staff for a prenatally defined fetal problem. A major factor in the development was the groundbreaking work of an obstetrician, Ian Donald, and an engineer, Tom Brown, at Queen Mother's Hospital in Glasgow, who produced an ultrasound instrument called the Diasonograph. The first screening program offering a systematic ultrasound examination to a large pregnant population began in Malmoe, in 1973 and aimed to detect twins. Since then the examination has evolved over the years to include a systematic evaluation of the intrauterine contents. A number of randomized controlled trials have been reported and several large studies have reported the efficiency of routine fetal examinations for the detection of anomalies. Detection rates for the various subsets are presented. The learning curve regarding the ability to detect anomalies and the importance of proper training has also been shown. The procedure ‘routine fetal examination’ has been significant in supporting the continuous development of fetal medicine. The consequences of the improved dating of every pregnancy and the in utero transport of a sick fetus rather than an emergency transportation of a sick neonate, have an established evidence base. Ultrasound technology has had a remarkable ability to trigger great technical minds to move the technology forward year after year. Through a continuous cooperation between technicians and clinicians, this impressive technology of ultrasound will continue to support our work for the unborn child. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient extraction of nucleolar proteins for interactome analyses
Authors: Chamousset Delphine , Mamane Sarah , Boisvert François‐Michel , Trinkle‐Mulcahy Laura 
Published: June 2010

AbstractThe efficient extraction of proteins from purified cellular organelles is critical for in vitro analyses, including identification of protein complex members by affinity purification‐based quantitative proteomic approaches. When applied to purified nucleoli, classic nuclear protein extraction methods inefficiently and selectively release only ∼50% of proteins. Here, we present a method that can extract up to 90% of nucleolar proteins, and apply it in a quantitative interactomic approach to identify nucleolar interaction partners for a mammalian protein phosphatase.
Proton and proton‐coupled electron transfer with paradigms towards single‐molecule systems
Authors: Kuznetsov A.M. , Ulstrup J. 
Published: June 2010

AbstractProton (PT), H‐atom and proton coupled electron transfer (PCET) are ubiquitously encountered in chemical and biological processes. PT and H‐atom transfer can belong to the partially or totally adiabatic limits representing ‘weak’ or ‘strong’ interactions between the donor and acceptor, reflected most conspicuously in large, i.e. ≫1 and small, i.e. 1–2, kinetic deuterium isotope effects (KIE). In view of the short proton/H‐atom transfer distances, the electronically adiabatic limit prevails in either case. The PCET notion applies from sequential PT and ET events to fully synchronous ET/PT as in H‐atom transfer. We first overview these notions. We then address several classes of PT reactions not commonly addressed in analytical condensed matter PT/H‐atom transfer theory. These include viscosity (relaxation) controlled PT and KIE < 1 in protein systems. Other classes are PT in strongly hydrogen bonded systems such as excess proton conduction in aqueous solution or in biological or synthetic membranes, and PT in the ‘inverted’ free energy region where excited proton vibrational states and a maximum in the Brønsted relation are important. We finally invoke an approach to single‐molecule PT and H‐atom transfer where the PT/H‐atom transferring molecules are enclosed between the substrate and tip in electrochemical (in situ) scanning tunnelling microscopy (STM) or between a pair of nanoscale electrodes. No data are presently available but could be within reach considering the recent success of in situ STM in single‐molecule electron transfer. Elusive notions such as PT/H‐atom transfer distances and distance dependent KIEs would become accessible based on this approach. Copyright © 2010 John Wiley & Sons, Ltd.
Particle size distribution in dilute liquid/liquid dispersions by light scattering
Authors: Lindsey E. E. , Chappelear D. C. , Sullivan D. M. , Augstkalns V. A. 
Published: June 2010

Abstract
Equal energy per unit mass (or volume) proved to be a valid scaling criterion for particle size distribution as well as mean particle size for geometrically similar vessels with a volume range of 4 to 1.
Binodal particle size distributions were observed. Although the coarse fraction varied as the −6/5 power of the agitation rate, the tine size was relatively independent of agitation rate.
The system with the greater drop viscosity gave a smaller fine‐fraction and a larger coarse‐fraction than the other system (IB/W).
Both systems approached equilibrium size slowly (many minutes). Equilibrium was approached more rapidly at high agitation rates. Differences were small between different tank sizes at equal energy dissipation rates per unit mass.
The average size of the fine fraction remains about the same through the run (although the amount increases). The size of the coarse fraction decreases with time. More experiments are necessary to elucidate the mechanism behind this.
Studies of the thermal behavior of polymers by torsional braid analysis
Authors: Gillham John K. , Lewis Armand F. 
Published: June 2010

AbstractThe application of the torsional braid technique to the thermal analysis of polymers (and monomers) is demonstrated. Included in this work are details of a visual method for estimating the dynamic mechanical damping factor of a freely oscillating system. Studies of a thermoplastic polymer and a thermosettiiig resin are presented in which their thermal behavior is demonstrated with respect to first and second order transitions, cure, thermal crosslinking and degradation. Isotactic polypropylene is studied as an example of a semi crystalline thermoplastic polymer. The monomer 1,3,5‐tria. crylylhexahydro‐8‐triazine represents an example of a thermosetting material. The dynamic mechanical data are compared with the results obtained by differential thermal analysis, thermo‐gravimetric analysis, and infrared spectroscopy.
Estimation of Z‐average molecular weight by light scattering in good solvents
Authors: Badley Jack H. 
Published: June 2010

AbstractThe unimodal molecular weight distributions found in many synthetic polymers can be fairly well characterized by the measurement of three different average molecular weights: the number‐, weight‐, and Z‐averages. The first two are easily measured; rhe third is more difficult to determine. This paper describes a light‐scattering method for the estimation of the Z‐average molecular weight which is applicable to random coil polymers in the molecular weight range between 0.2 × 106 and 2 × 106 and for which a suitable solvent is available. The solvent may be either a theta solvent or a good solvent for which the relation between intrinsic viscosity and molecular weight is known. The method depends on the fact, that, when angular dissymmetry of scattered light is observed, the Z‐average mean‐square radius of gyration of the polymer molecules, r2 can be determined. In a thela solvent, r2 is proportional to M, so that measurement of rz2 is equivalent to the determination of M̄z. In good solvents, r2 = kMb, and the corresponding molecular weight, called M̄d, is slightly different. The parameters k and b are derived from the relation between intrinsic viscosity and molecular weight in the test solvent. Provided that the dispersion of molecular weight is not too great, M̄d does not differ widely from M̄z, as b cannot exceed 1.2 for random coil molecules. Experimental tests in toluene on narrow molecular weight fractions of poly‐a‐methyl‐styrene and binary combinations of them gave results in accord with theory.
Diffusion in amorphous polymers
Authors: Paul D. R. , DiBenedetto A. T. 
Published: June 2010

AbstractDiffusion and solubility coefficients are presented for He, Ne, Ar, and N2 in three ethylene‐propylene copolymers, two styrene‐butadiene copolymerg and a cis‐poly‐butadiene for five temperature levels in the range 0–50°C. The data were obtained by using a slightly modified Dow Gas Transmission Cell and analyzed by a new modified time‐lag technique which properly accounts for the increase in pressure on the downstream side of the cell. Activation energies were calculated for the twenty‐four diffusion systems and correlated with the polymer intermolecular forces and the gas molecule sizes by using ii cell theory for amorphous polymers which employs a potential energy depth parameter, ϵ*, a range parameter, p*, the number of degrees of freedom per structural unit (center), 3Cm, and the number of centers per unit cell, n. The first three parameters were evaluated from thermodynamic data, while n was evaluated from the diffusion data. It is believed that n is an indication of the number of backbone carbon atoms active in polymer segmental motion. The values obtained here (5–9) agree well with existing values estimated from polymer viscous flow data. A correlation for the solubility data is shown and a linear free energy relationship is discussed.
Gamma‐Radiation‐Induced Polymerization of Ethylene
Authors: Kukacka L. E. , Colombo P. , Steinberg M. 
Published: June 2010

AbstractThe kineties and product characteristics of the Co60 gamma‐radiation‐induced polymerization of ethylene have been studied as a function of pressure, radiation intensity, and temperature. Experiments were carried out under conditions which ranged in pressure from 170 to 1360 atm., in temperature from 20° to 200°C., and in radiation intensity from 5.8 × 1014 to 8.5 × 105 rad./hr. Activation energies of 0.2 and 14.5 kcal./mole were determined for the temperature ranges 20° to 100°C and 120° to 200°C., respectively. Empirical relationships for the rate of polymerization and the radiation yield for the range of pressure and radiation intensity studied and for temperatures between 20 and 100°C., are as follows: Q = (1.39 ± 0.37) × 10−8e−200/RT p2.7I0.5; G = (3.50 ± 0.95)e−200RTp2.5I−0.5, where Q = polymerization rate, g./l.‐hr., G = radiation yield, molecules/100 e.v., P = pressure, atm., and I = radiation intensity, rad./hr. The 0.5 power dependence of the intensity on rate indicates a free radical mechanism. The polymers produced over the entire range of conditions were found to be completely soluble. Densities ranged from 0.95 g./cc. for material formed at 20°C. to 0.91 g./cc. for material formed at 120°C. The weight average molecular weight decreased from 1.5 × 1016 to 4.7 × 104 over the same temperature range. The molecular weight was found to increase with pressure and with decreasing radiation intensity. All polymers formed at temperatures below 120°C. had a melt index of < 0.06 g./10 min.
Thermodynamic and molecular properties of amorphous high polymers
Authors: Paul D. R. , Dibenedetto A. T. 
Published: June 2010

AbstractA potential energy function and an equation of state for amorphous polymers are developed by using a mathematical, quasi‐lattice model to represent the molecular structure. The potential energy function, obtained by dividing a polymer chain into a linked series of interaction centers, is described by three molecular parameters: e*, a force constant which measures the strength of interaction between two polymer segments, p*, a range parameter which measures the minimum separation between point centers on adjacent segments, and l, a structural parameter which indicates the size of the molecular units. A theoretical equation of state is then developed by defining a cell partition function for a polymer segment in terms of the potential energy function and one additional parameter, 3Cm, which is a measure of the number of external degrees of freedom possessed by an interaction center. It is shown that the theoretical equation for the thermal expansion at constant pressure simplifies to:

Similar expressions are developed for compressibility, internal pressure, and cohesive energy density. Experimental data for 13 polymers are then correlated using the theoretical equations. Densities, thermal expansion coefficients, and internal pressure measurements are used to evaluate the molecular parameters. Internal pressures over a range of temperatures are correlated to within 1% (in the best case). The cohesive energy density and the glass transition temperature are also interpreted in terms of the model. The molecular force parameters are also evaluated by a modified Slater‐Kirkwood calculation, and the results are compared to the experimentally determined values. A physical interpretation is then discussed in light of these calculations. The tentative conclusions are that the thermodynamic properties of amorphous polymers can be correlated with a model containing four molecular parameters. Two of these parameters, e* and p*, are associated with the nature of the interaction potential between structural units along the chain and can perhaps be estimated theoretically. The parameter l, a measure of the size of a structural unit on a polymer chain, has a strong effect on the repulsion between polymer segments and must be evaluated from experimental data. The parameter 3Cm is a measure of the mobility and freedom of a polymer chain and must be evaluated from experimental data. The change of a given polymer from a rubbery to a glassy state probably can be related to large changes in this latter parameter.
Étude par Spectrographie Infra‐rouge de Quelques Modifications de la Structure des Fibres de Polyamides Provoquées par les Traitements d'Ennoblissement (Fixage Thermique, Texturation)
Authors: Bouriot P. , Parisot A. 
Published: June 2010

AbstractStructural changes induced in nylon 66 fibers by heat‐treatment during industrial texturizing processes (at 165 and 200°C.), whether or not followed by steam‐setting at 130°C., have been investigated by means of infrared spectroscopy. Variations observed in the optical density of crystalline (935 cm.−1) and amorphous (1140 cm.−1) bands show a general increase in crystallinity of the polyamide, owing to heat treatment, chiefly in the water vapor phase. The crystallizing effect of steam‐setting seems all the stronger as the initial crystallinity of the specimen is smaller. In the case of dry‐heat treatments, crystallinity rises in the order of increasing temperatures. Likewise, heavy‐water accessibility diminishes also, owing to heat‐treatment, and chiefly in the water vapor phase. The examination by polarized light of NH and ND groups in fibers treated with heavy water shows a decrease in the degree of orientation of inaccessible and accessible areas under the influence of heat. This denotes some disorientation of the structure as a whole. No significant changes can be observed in the mean energy of hydrogen interactions, however. A general interpretation of the phenomena observed is suggested.