bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical Outcomes Following Institution of Universal Leukoreduction of Blood Transfusions for Premature Infants
Authors: Fergusson Dean , Hébert Paul C. , Lee Shoo K. , Walker C. Robin , Barrington Keith J. , Joseph Lawrence , Blajchman Morris A. , Shapiro Stan 
Published: April 2003

ContextLeukocytes present in stored blood products can have a variety of biological effects, including depression of immune function, thereby increasing nosocomial infections and possibly resulting in organ failure and death. Premature infants, given their immature immune state, may be uniquely predisposed to the effects of transfused leukocytes.ObjectiveTo evaluate the clinical outcomes following implementation of a universal prestorage red blood cell (RBC) leukoreduction program in premature infants admitted to neonatal intensive care units (NICUs).Design and SettingRetrospective before-and-after study conducted in 3 Canadian tertiary care NICUs from January 1998 to December 2000.PatientsA total of 515 premature infants weighing less than 1250 g who were admitted to the NICU, received at least 1 RBC transfusion, and survived at least 48 hours were enrolled. The intervention group consisted of infants admitted in the 18-month period following the introduction of universal leukoreduction (n = 247) and the control group consisted of infants admitted during the 18 months prior to the introduction of universal leukoreduction (n = 268).Main Outcome MeasuresPrimary outcomes were nosocomial bacteremia and NICU mortality, compared before and after implementation of universal leukoreduction using multivariate regression. Secondary outcomes included bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and intraventricular hemorrhage.ResultsThe proportion of infants who acquired bacteremia after an RBC transfusion was 79/267 (29.6%) in the nonleukoreduction period and 63/246 (25.6%) in the leukoreduction period. For NICU mortality, there were 45 deaths (16.8%) in the nonleukoreduction period and 44 deaths (17.8%) in the leukoreduction period. The adjusted odds ratio (OR) for bacteremia was 0.59 (95% confidence interval [CI], 0.34-1.01) and for mortality was 1.22 (95% CI, 0.59-2.50). The adjusted ORs for bronchopulmonary dysplasia and retinopathy of prematurity were 0.42 (95% CI, 0.25-0.70) and 0.56 (95% CI, 0.33-0.93), respectively. The adjusted ORs for necrotizing enterocolitis and grade 3 or 4 intraventricular hemorrhage were 0.39 (95% CI, 0.17-0.90) and 0.65 (95% CI, 0.35-1.19), respectively. The adjusted OR for a composite measure of any major neonatal morbidity was 0.31 (95% CI, 0.17-0.56). Crude and adjusted rates for all secondary outcomes suggest that leukoreduction was associated with improved outcomes.ConclusionImplementation of universal prestorage leukoreduction was not associated with significant reductions in NICU mortality or bacteremia but was associated with improvement in several clinical outcomes in premature infants requiring RBC transfusions.
Improving the Process of Informed Consent in the Critically Ill
Authors: Davis Nicole , Pohlman Anne , Gehlbach Brian , Kress John P. , McAtee Jane , Herlitz Jean , Hall Jesse 
Published: April 2003

ContextInvasive procedures are often performed emergently in the intensive care unit (ICU), and patients or their proxies may not be available to provide informed consent. Little is known about the effectiveness of intensivists in obtaining informed consent.ObjectivesTo describe the nature of informed consent in the ICU and to determine if simple interventions could enhance the process.Design, Setting, and PatientsProspective study of 2 cohorts of consecutively admitted patients (N = 270) in a 16-bed ICU at a university hospital. All patients admitted to the ICU during the baseline period from November 1, 2001, to December 31, 2001, and during the intervention period from March 1, 2002, to April 30, 2002, were included.InterventionA hospital-approved universal consent form for 8 commonly performed procedures (arterial catheter, central venous catheter, pulmonary artery catheter, or peripherally inserted central catheter placement; lumbar puncture; thoracentesis; paracentesis; and intubation/mechanical ventilation) was administered to patients or proxies. Handouts describing each procedure were available in the ICU waiting area. Physicians and nurses were introduced to the universal consent form during orientation to the ICU.Main Outcome MeasuresIncidence of informed consent for invasive procedures at baseline and after intervention; whether the patient or proxy provided informed consent; and understanding by the consenter of the procedure as determined by the responses on a questionnaire.ResultsFifty-three percent of procedures (155/292) were performed after consent had been obtained during the baseline period compared with 90% (308/340) during the intervention period (absolute difference, 37.4%; P&amp;lt;.001). During baseline, the majority (71.6%; 111/155) of consents were provided by proxies. This was also the case during the intervention period in which 65.6% (202/308) of consents were provided by proxies (absolute difference, 6.0%; P = .23). Comprehension by consenters of indications for and risks of the procedures was high and not different between the 2 periods (P = .75).ConclusionsInvasive procedures are frequent in the ICU and consent for them is often obtained by proxy. Providing a universal consent form to patients, proxies, and health care clinicians significantly increased the frequency with which consent was obtained without compromising comprehension of the process by the consenter.
Energetics and reproductive effort
Authors: Ellison Peter T. 
Published: April 2003

AbstractNatural selection favors the optimal allocation of energy and other limiting resources to reproduction. Human reproductive physiology displays characteristic patterns that can be viewed as mechanisms that help optimize reproductive effort in the face of environmental energetic constraints. Female ovarian function is particularly sensitive to energy balance and energy flux, resulting in a synchronization of conception with favorable energetic conditions. Reproductive effort during gestation is highly buffered from environmental energetic constraints, but the duration of gestation and final birthweight are both very sensitive to maternal energy availability. Milk production during lactation is relatively buffered from maternal energetic constraints as well, but the duration of lactational amenorrhea is sensitive to the relative metabolic load of lactation. Male gamete production is very insensitive to energetic constraints, but variation in testosterone production in response to both age and longer‐lasting energetic conditions contributes to the modulation of somatic and behavioral aspects of male reproductive effort, aspects that are more energetically costly for a male. There is also new evidence that testosterone may also help to modulate the trade‐off between male parenting and mating effort. Am. J. Hum. Biol. 15:342–351, 2003. © 2003 Wiley‐Liss, Inc.
Adult‐onset asthma and wheeze among irritant‐exposed bleachery workers
Authors: Andersson Eva , Olin Anna‐Carin , Hagberg Stig , Nilsson Ralph , Nilsson Tohr , Torén Kjell 
Published: April 2003

AbstractBackgroundWhether new‐onset asthma is associated with irritant exposure is unclear. The aim was to investigate if occupational exposure to irritant gases, especially repeated peak exposure (gassings), increased the risk of obstructive airways disease.MethodsData on airway symptoms and exposure among bleachery (n = 101) and paper department workers (n = 314) were collected by a questionnaire. Incidence rates and hazard ratios (HR) (Cox regression) were calculated. Non‐responders were interviewed by telephone.ResultsThe incidence rate for adult‐onset physician‐diagnosed asthma among bleachery workers reporting gassings giving rise to respiratory symptoms was 7.6/103 person‐years and for those without gassings 2.2/103 person‐years, compared to 1.0/103 person‐years for paper workers. In a Cox regression model for asthma (n = 12), stratified for sex, HR for gassings were 5.6 (95% confidence intervals (CI) 1.6–20), for hay fever 3.0 (95% CI 0.8–11), and for ever smoking 0.7 (95% CI 0.2–2.4). The same model for adult‐onset wheeze gave HR of 5.2 (95% CI 2.2–12), 1.7 (95% CI 0.6–5.4), and 1.1 (95% CI 0.5–2.7), respectively.ConclusionsRepeated peak exposure to irritant gases, here studied as gassings in the pulp industry, increased the risk for both adult‐onset asthma and wheeze. Am. J. Ind. Med. 43:532–538, 2003. © 2003 Wiley‐Liss, Inc.
Mastication. IX. Shear‐dependence of degradation on hot mastication
Authors: Mullins L. , Watson W. F. 
Published: April 2003

AbstractA comparison between the viscosity‐molecular weight relationships for natural rubber degraded in thin films at 130 and 140°C. and on cold and hot mastication indicates a greater similarity of distribution on degradation by the mastication treatments. The hot mastication process is further differentiated from ordinary thermal reactions by the dependence of rate of degradation on the rate of shear. It does, however, differ from cold mastication in being primarily an oxidative‐scission reaction. No differences were detected in the properties of networks prepared from rubbers masticated at high or low temperatures to the same level of degradation.
An apparatus for quantitative gas‐absorption measurements
Authors: Shelton J. Reid , McDonel E. T. 
Published: April 2003

AbstractAn apparatus for quantitative gas‐absorption measurements is described and illustrated with drawings and photograph. A commercially available aluminium block heating unit, adapted to accommodate glass sample tubes, is mounted in an octagonal frame. Gas burets and leveling bulbs are supported on the frame to provide an apparatus for measuring volume changes at a given pressure. Data on rate of heatup and temperature distribution within a sample tube are given. The apparatus has been used primarily for volumetric oxygen‐absorption measurements in studies related to the oxidation of rubber, but it is adaptable to studies involving other materials and other gaseous atmospheres at controlled temperatures. For example, studies have been made with polyethylene, epoxide coatings, and drying oils. The apparatus has also proved useful for curing polyurethanes under moisture‐free conditions and for the vulcanization of rubber in a nitrogen atmosphere.
Studies on orientation phenomena by fiber formation from polymer melts. Part II. Theoretical considerations
Authors: Ziabicki Andrzej 
Published: April 2003

AbstractThe mechanism for orientation of macromolecules through the melt‐spinning of synthetic fibers is analogous to that in polymer solutions flowing in capillaries or in a Couette apparatus. The differences between the two processes, with regard to the velocity field, molecular state, and time dependencies, have been discussed and the differential equations derived to describe the orientation of two extreme molecular models. The coefficients of orientation for fibers consisting of rigid particles (model I) and flexible, coiled chains (model II) have been defined. The specific conditions occuring in fiber‐spinning experiments have been shown, as well as the possibility of applying such experiments to the study of the behavior of macromolecules in the molten state.
The effect of the sorption process on the dynamic rigidity modulus of the wool fiber
Authors: Mackay B. H. , Downes J. G. 
Published: April 2003

AbstractUsing a torsion pendulum, measurements have been made of the dynamic modulus of rigidity of wool fibers during the process of sorbing or desorbing water (from the vapor phase). Anomalous behavior is observed, with low values of rigidity which cannot be accounted for in terms of equilibrium data. It appears that transient stresses occurring during sorption and desorption cause a temporary lowering of the rigidity modulus.
A vibrating reed apparatus for measuring the dynamic mechanical properties of polymers
Authors: Newman Seymour 
Published: April 2003

AbstractA vibrating reed apparatus for the measurement of dynamic Young's modulus has been constructed. The apparatus utilizes (a) a sensitive capacitance pick‐up to measure displacement of a reed having approximately 0.001 g. of silver painted on the free end of the reed, (b) a clamp assembly which permits placement of the specimen in small temperature‐controlled chambers, and (c) a linear variable differential transformer to facilitate maintenance of constant amplitude (independent of frequency) of the clamped end of the reed.
The measurement of molecular orientation in fibers by acoustic methods
Authors: Moseley W. W. 
Published: April 2003

AbstractIn the present work, the sound velocity in polymeric fibers or film strips is related to a quantitative measure of molecular orientation in the sample. It is shown that this measure of orientation can be calculated from two experimental quantities: the sound velocity in an oriented specimen and the velocity in a randomly oriented sample. Both the oriented and unoriented samples must have the same chemical composition, and both measurements must be made at the same temperature, below the glass transition temperature, Tg. Sound velocities were measured by a pulse technique. This method permitted a continuous measurement of orientation changes during conventional stress‐strain tests without interrupting the tests. In addition, the uniformity of orientation along the length of fibers was measured continuously during windup. Examples of these applications are given, and a comparison is drawn between acoustic and x‐ray measures of orientation.
Loss of antioxidants from polyethylene by evaporation and aqueous extraction
Authors: Hawkins W. L. , Worthington M. A. , Matreyek W. 
Published: April 2003

AbstractPolyethylene containing various types of antioxidants was either heated in a stream of nitrogen or placed in water maintained at several different temperatures under nitrogen. The polymer was then oxidized to determine how greatly the evaporation or extraction treatment had reduced the antioxidant effectiveness as compared with a control. Polymeric materials and carbon blacks were more completely retained than monomolecular organic compounds. The presence of carbon black did not greatly alter the rate of loss for any of these substances except Santonox, which was almost completely retained.
The mechanical properties of latex‐treated papers
Authors: Heyse W. T. , Sarkanen K. , Stannett V. 
Published: April 2003

AbstractThe effect of the amount and type of latex on the mechanical properties of the paper‐polymer combinations is described in detail. The treatment with latex increases the wet and dry strength properties of the paper considerably, together with improving the folding and tearing resistance. If the polymer in latex is below its film‐forming temperature, however, the beneficial effects of latex treatment are absent. Limitations to varying the rheological properties of plasticpaper combinations are imposed by the comparatively inextensible nature of the paper matrix. Methods of improving the extensibility of paper, including the use of synthetic fiber papers, are discussed, and the time‐dependent nature of the properties are outlined.
Effect of molecular structure on mechanical properties of epoxy resins
Authors: Erich Walter , Bodnar Michael J. 
Published: April 2003

AbstractThe effect of varying the molecular structure of epoxy resins on their mechanical properties when used as adhesives was studied. The work was directed toward preparation of bisphenols of the general formula HOϕCR(R′)ϕOH where R and R′ are either alkyl or alicylic substituents, in which case the benzhydryl carbon is incorporated in a cyclopentane or cyclohexane ring for use in the preparation of glycidyl polyethers having the formula:magnified imagewhere B is the divalent hydrocarbon radical of the bisphenol andnis an integer of the series 0, 1, 2, 3… Preparation of 13 epoxy resins which are liquids at room temperature is described. The effect of varying the structure of the dihydric phenol in the epoxy resin on the strength of adhesive‐bonded joints was determined. The results indicate that relative bonding strengths of epoxy resins synthesized from various bisphenols can probably be attributed to the symmetry and chain length of the substituents attached to the carbon atom connecting the two aromatic nuclei. There is a high correlation between adhesive properties and steric influence of a substituted methyl group. Although the qualitative features of substitution on the central carbon atom are shown to be fairly well understood, there are a number of points that still require clarification. For instance, a more conclusive picture of the effect of branching is desirable. Also, there are uncertainties about the magnitude of the temperature effect and the influence of the substituent on the impact values.
A modified helical spring stress relaxometer for automatic and manual operation
Authors: Dunn J. R. , Scanlan J. 
Published: April 2003

AbstractA relatively simple and inexpensive automatic and self‐recording apparatus giving good accuracy has been developed for measurement of chemical stress relaxation in elastomer vulcanizates. The apparatus is based on a previously described helical spring relaxometer intended for manual operation. Several improvements applicable to this manually controlled instrument are also described.
The gelation point of alkyd resins
Authors: Jonason M. 
Published: April 2003

AbstractUsing Flory's basic method, an equation is derived for the gelation point of oil‐modified alkyd resins in which account is taken of the different reactivities of the various carboxyl groups. The resultant modified equation is useful when phthalic anhydride is used as the dibasic acid because of the widely differing carboxyl group reactivities which occur in this case. If adipic or isophthalic acid is used as the dibasic acid, the gel point equation deduced by Flory's original method, which takes no account of reactivity differences, may be used. In such a case the difference between the observed and calculated gel point is about 5% when the polyhydric alcohol used is trifunctional and 8–9% when the polyhydric alcohol used is tetrafunctional. The modified gel point equation, applicable when phthalic anhydride is used as the dibasic acid, is shown to predict gel points with similar degrees of accuracy, discrepancies being also greater for alkyds using tetrahydric alcohols than for alkyds using trihydric alcohols. The discrepancy is believed to be due to the occurrence of intramolecular condensation, and it is contended that the degree of such intramolecular condensation in branching systems is proportional to some function of the branch unit functionality.
The permeability of some graft copolymers of polyethylene to gases and vapors
Authors: Myers A. W. , Rogers C. E. , Stannett V. , Szwarc M. , Patterson G. S. , Hoffman A. S. , Merrill E. W. 
Published: April 2003

AbstractGraft copolymers of polyethylene were prepared by gamma irradiation of polyethylene films immersed in the appropriate monomer. The majority of gas permeability measurements were made by Barrer's high vacuum technique; others were made by measuring volumetric change as a function of time. Sorption isotherms were obtained by using a quartz helix microbalance. Temperature dependent permeability constants have been obtained for permeation of oxygen, nitrogen, and carbon dioxide through styrene, acrylonitrile, and vinylpyridine grafted to low‐density polyethylene. Permeability constants at 25°C. have also been determined as a function of water vapor partial pressure for the above systems. Some values for permeation of carbon dioxide through styrene grafted to high density or linear polyethylene are also given. Organic vapors studied were methyl bromide and isobutene, permeability constants at 0°C. being determined for styrene and acrylonitrile–polyethylene graft copolymers as a function of organic vapor pressure. The data show clearly that permeation through acrylonitrile and vinylpyridine–polyethylene grafts is primarily a diffusion process, while in permeation through polyethylene–styrene grafts, there is also a crystallite solution effect. Percentage grafts varied from 0 to 100 parts monomer per 100 parts by weight polyethylene.
Catalysis of the isocyanate‐hydroxyl reaction
Authors: Britain J. W. , Gemeinhardt P. G. 
Published: April 2003

AbstractThe reaction of toylene diisocyanate (80/20 mixture of 2,4 and 2,6‐isomer) with a secondary hydroxyl‐containing polyoxypropylene triol was studied in the presence of numerous compounds to test their catalytic effect on the reaction. The reaction was studied by determination of the gelation time of the reaction mixture. Many metallic compounds were found to be good catalysts for the isocyanate‐hydroxyl reaction. Compounds in roughly descending catalytic activity are: Bi, Pb, Sn, triethylenediamine, strong bases, Ti, Fe, Sb, U, Cd, Co, Th, Al, Hg, Zn, Ni, trialkylamines, Ce, Mo, V, Cu, Mn, Zr, trialkyl phosphines. Similar gelation tests were made with m‐xylene diisocyanate and the same triol and also with hexamethylene diisocyanate and the triol. In these tests the order of strength of the catalysts was found to be different than when tolylene diisocyanate was used. In decreasing order of activity: Bi, Fe, Sn, Pb, Ti, Sb, strong bases, Co, Zn, triethylenediamine, trialkyl amines. A mechanism is proposed for the way in which a metal compound may catalyze the isocyanate‐hydroxyl reaction. Steric hinderance is suggested to explain the differing catalytic activity observed with tolylene diisocyanate and the unhindered aliphatic diisocyanates.
Measurement of adhesion by a blister method
Authors: Dannenberg Hans 
Published: April 2003

AbstractAn instrument for the measurement of the adhesion of organic coatings has been developed. It is based on the formation of a blister by injecting a liquid (generally mercury) under pressure between the coating and the substrate. The work of detachment, i.e., the energy needed to detach 1 cm.2 of coating, is determined by recording the liquid pressure as a function of the injected volume and computing the area under this curve. Extraneous factors such as deformation of the film and compressibility of the liquid are eliminated through a blank run. The design and operation of the instrument are described, an evaluation of its performance and limitations is given, and examples of its application are presented. The method should be useful for accurate measurement of adhesion of many types of surface coatings to metal and, possibly, to other substrates, as well as for studies of the various factors that influence adhesion.